AVS Forum Archive 2 - Why does the kd34xbr960 need 1400 line of resolution.

subysouth

11-14-04, 02:36 AM

Originally posted by gdg
I'm perceiving a fundamental conceptual problem here. Are scan lines not the same as lines of resolution? (because 480i technically requires 960 scan lines)

Ps I'm guessing you're going to tell me they're not the same but in that case how is it possible to have ~480 "lit up" lines and the same number of dark lines if each line was not a separate line of resolution.

480i is exactly 480 horizontal lines(counted vertically) and no specified horizontal resolution but a 4:3 profile scanned in an interlaced fashion.

The electron beam acts like a thin paintbrush moving back and forth horizontally across the screen painting the image. The ideal image in no overlap but no gaps between the lines - a completely painted canvas. You dont want to see the lines if possible, thats why progessive scanning is better.

When you heard the set manufacturers claiming horizontal lines of reolution in the old days they were making claims(often wildly inaccurate) about how many horizontal pixels their sets could do. The vertical resolution was non-negotiable, it was always 480 in an interlaced fashion. So the only way they could differentiate their sets would be to claim their higher priced sets did 900 horizontal lines/pixels of res vs say 600 on another set. It often was wildly exaggerated but who really cared right? Again the vertical was fixed at 480 regardless.

Enter SD digital which began specifying a horizontal res at 640. SD NTSC digital is supposed to be 640x480i.

Next enter ATSC also specifying both horizontal and vertical resolution. 1080i = 1920x1080i. 720p = 1280x720p.

Problem is CRT tech cant make that leap in resolution for technical reasons on medium to large CRT screens. But CRT was the prevalent tech and set manufacturers needed to start making "HD" sets, and thus began the truth stretching on the CRTs.

ss

subysouth

11-14-04, 02:41 AM

Couple of ninja post deletes eh?

Caught and responded to anyway.

ss:)

gdg

11-14-04, 02:51 AM

I'm beginning to understand and, being an audiophile, am familiar with the game of specmanship that gets played. Having said that, trying to impose (paint/light up) 1080 lines over 517 (or 623 for that matter) is obviously a waste of time. It would seem that many of the extra lines in the Sony will simply repeat information. So why can one see such a large improvement when viewing an HD source on a CRT? According to what you are telling me, virtually all the extra info is lost. Is it mainly the horizontal that actually benefits?

gdg

11-14-04, 02:53 AM

Ps Does one have to go to Plasma or LCD to get the real benefit of HD?

gdg

11-14-04, 03:06 AM

Pps.
Bottom line, what is your opinion on the Sony and why the general consensus that the crt still gives the best picture (assuming size and weight are not an issue). Is Princeton the way to go?

subysouth

11-14-04, 03:53 PM

Originally posted by gdg
I'm beginning to understand and, being an audiophile, am familiar with the game of specmanship that gets played. Having said that, trying to impose (paint/light up) 1080 lines over 517 (or 623 for that matter) is obviously a waste of time. It would seem that many of the extra lines in the Sony will simply repeat information. So why can one see such a large improvement when viewing an HD source on a CRT? According to what you are telling me, virtually all the extra info is lost. Is it mainly the horizontal that actually benefits?

Its the huge increase in the inherent info in the signal itself that is the biggest increase in picture quality. Even though ALL of it is not being displayed, the amount that is still absolutely trumps what most people are used to.

Consider that much analog 480i only carried about 350 distinct pixels in both the horizontal and maybe slightly les than that in the vertical. [Don't get caught up on the vertical line count being 480, just because its 480 doesnt mean the actual signal carried 480 distinct vertical pixels, they can repaet the same info in adjacent lines.] Lets call the actual resolution of an avergae NTSC analog cable channel 350x300 for arguments sake.

Now juxtapose that against 1080i or 720p. The original mandates for ATSC were defining both horizontal and vertical resolutions. It didnt take long for broadcasters to work on some leniency in the horizontal range(just like they had been enjoying in the NTSC signal.) So depending on who you ask, while the vertucal resolution of 1080i and 720p are non-negotiable the horizontal rates are. And in the defense of the broadcasters, the data content(and bandwidth required to dispense it) is hugely different from NTSC to ATSC. It would be like telling auto manufacturers that in 6 years all their cars need to be able to get 50mpg. Its a big transition and big transitions cut into profits. Signal providers are already flush with subscribers, how does it help their bottom line giving a better signal at more expense to them when they already have the subscribers? It doesnt, so theyve been throwing roadblocks in the path the whole. But for satellite, ATSC might have been scuttled entirely by the cable providers.

Are you seeing how the game works?

Thats the long answer, even the horizontally deprived 1080i signal thats being sent over the lines today(mostly 1440x1080i) has about 13-16 times more actual content than your avergae old NTSC channel did. Even though this Sony cant actually reproduce it all, it still is lightyears better than what you had, thus the WOW factor. And the reason a lot of the chain bringing HD to the consumers is like "why bother"? They know they could have wowed consumers on an average TV set(say 42" and under) with a heck of a lot less inherent resolution than 720p or 1080i. That kinda content is unnecessary on the average sized TV set unless you are sitting really close. It is however necessary on legitimate home theater displays(say 60"+).

Sony would still WOW the heck out of people if they drove their sets at their actual resolution(say 620p on the 34XBR960) but it wouldnt fall into "HD" but the picture would be even better than it is now because it would eliminate line redraw and be progressive. The reason you dont see scan lines on 1080i on the Sony is cause it doesnt have the lines to ignore in each field.

To ask widely varying screen sizes to do the same or similar resolutions at relatively the same distances is the inherent illogic of the HD standards.

Starting to make sense? Its a lot more complicated game than the simple surface would imply.

ss

subysouth

11-14-04, 04:00 PM

Originally posted by gdg
Pps.
Bottom line, what is your opinion on the Sony and why the general consensus that the crt still gives the best picture (assuming size and weight are not an issue). Is Princeton the way to go?

The reason is the signal range a CRT produces and the speed it transitions is very human eye friendly. The human is very sensitive to subtle color changes and precisely can divide motion. The CRT is just the best device going that can do all these things well. Plasmas are getting better and operate a lot like a CRT in some ways. Problem with CRTs is their size limits(

SED is showing real promise of bringing CRT picture quality to a larger display.

Time will tell.

If I were to buy a 34" CRT right now, I would be looking for a now defunct Sampo or one of the other more reliable 34" units based on a high volume CRT unit. But know that youre gonna have to invest the effort in a HTPC to make it work right.

I personally am loooking at an ED 42" plasma beacuse of my viewing distance (10'.) Thats a little beyond its sweet spot, but I have exceptional vision.

ss

gdg

11-14-04, 05:47 PM

The problem is that, each answer, generates more questions. That said I'll understand when you run out of patience.

Here's a couple more:

When you say high volume CRT do you mean, mass produced? Couldn't one somehow bypass the Sony's processing and drive it by a computer?

Also, is there any way to calculate how much of an actual increase in resolution the Sony practically produces over the classic NTSC display?
In other words, though shortchanged, just how close does the 960 actually get to the potential offered by HD?
Or...... are there simply too many variables in the original content to say?

Finally, can you suggest the best place where I might research the aspects of HTPC that I would need in order to push a CRT to it's limits if driven by a computer?
Why isn't this capability built into some high end devices? Is it because the sources vary too widely and each situation has to be custom tailored?

subysouth

11-14-04, 06:52 PM

Originally posted by gdg
The problem is that, each answer, generates more questions. That said I'll understand when you run out of patience.

Here's a couple more:

When you say high volume CRT do you mean, mass produced? Couldn't one somehow bypass the Sony's processing and drive it by a computer?

Also, is there any way to calculate how much of an actual increase in resolution the Sony practically produces over the classic NTSC display?
In other words, though shortchanged, just how close does the 960 actually get to the potential offered by HD?
Or...... are there simply too many variables in the original content to say?

Finally, can you suggest the best place where I might research the aspects of HTPC I would need in order to push a CRT to it's limits if driven by a computer?
Why isn't this capability built into some high end devices? Is it because the sources vary too widely and each situation has to be custom tailored?

I always try my best to be patient with people who are ready to truly understand something. And there is no easy answer thats why each answer creates more questions. There is no perfect boxed solution out there right now in the CRT HD arena, but I just today learned there may be one close - see below.

When I say high volume I mean you want a tube and as many electronics possible with a proven track record. Even the handful of sets that offer computer input are built by larger corporations and sold to these lower volume sellers for modification to their specs. Princeton doesnt make their tubes, they order them to their specs or order already engineered sets and build-in further control over their inherent resolution. The only fully custom CRT tv tube I am aware of ever being built was the PG AF3.0HD, driven by the input of Joe Kane. But there are a lot of great tubes out there that if correctly driven would be great displays.

It would be possible I think to convert the Sony to digital input but not easily and would require a huge skills set. Also I am not sure thats the best choice(getting past the difficulty of it) because the smaller pitch of the Sony screen is only a benefit if you sit closer(sub 6') and it does have a downside in that it reduces light output. [Thats why I think the Sony's have the light fogging in the tube is because they are overdriving the smaller phosphors to equal the light output of the larger pixel sets.] Other 34" sets with larger pixels and lower inherent res might be better if you are sitting at more typical distances. The Sampo 34" as a choice come to mind.

Interms of what this Sony is doing with the only HD signal it supports,1080i, I think I covered it pretty well above. It is scanning 1080i lines over about 623 of actual available vertical resoution and whatever the horizontal content of the 1080i signal is(the braodcasters are already "cheating" on that part lets call it 1400) to about 1100 of available horizontal resolution.

So youre getting ~623 pixels of muddied vertical resolution and about 1100 of horizontal resolution(also muddied because of the line redraw.) It still looks great compared to NTSC becasue as I explained above NTSC is horribly pixel deficient(say 350x300.)

Now since my last posting I did find a bit of good news in the 34" CRT arena. The Toshiba 34HF84 and 34HXF84 allow for all inputs(including 720p and 1080i) to be scaled to 540p which is very close to the sets actual inherent resolution. I was unaware that any of the big name brands(Panasonic, JVC, Sanyo, Sony, or Toshiba) were supporting 540p on a 34" set. Simply put, it may be the best looking easiest to use HD set out there because of its approach and allowance for 540p. I am still reading about the set but my belief in progressive scanning near actual resoution puts that 34" at the top of the heap of sets that lack scalable computer input. Look hard at this set if you like 34" CRTs.

ss

subysouth

11-14-04, 07:07 PM

Originally posted by gdg
Finally, can you suggest the best place where I might research the aspects of HTPC that I would need in order to push a CRT to it's limits if driven by a computer?
Why isn't this capability built into some high end devices? Is it because the sources vary too widely and each situation has to be custom tailored?

Missed the last two. Look here for starters on general HTPC info:

http://www.keohi.com/keohihdtv/experttips/markrejhon/htpc_superguide.html

Why not on high volume sets even the expensive ones? Because A) few people actually understand it or why it would be a benefit B) cost and C) potential service calls by confused customers and trying to track the problem to the set or the input. Tell them its an HD, make the picture look pretty good and most people are happy. The only way to convince them would be show them even better, then they could drive manufacturers to include such features.

I personally would be thrilled if Sony just said look, the sets native resolution is 1100x625 and were driving everything at that rate progressively. The catch is, it wouldnt be HD. And it saying HD sells.

All that adds up to the set manufacturers have no reason to do it.

Faroudja does make a device that works very similary in the scaling aspects to a HTPC, the Native Rate scaler, but they are AFAIK still limited to a group of established output resolution rates(800x600, 1280x720, 1366x768 etc.)

True pixel mapping can only be done on HTPC with variable pixel output rates. The weird actual rates of direct view CRTs can only be fully explored by a HTPC.

Getting close, see the Toshiba info above, is good enough for 99% of people. I think I am in that 99% because the Toshiba is very appealing in its direct simplicity. I am now considering the 42" ED plasmas and those 540p Toshiba sets. I am a little far at 10' for the Toshiba set, but that beautiful CRT picture is enticing.

ss

gdg

11-14-04, 09:03 PM

I have a Toshiba 34hf83 sitting here in my bedroom that I was about to sell in favor of the Sony. It also has user selectable 540p. I noticed this when I bought it but thought it was just Toshiba playing with the numbers.
I decided to "upgrade" because I was finding that the black wasn't as deep as I had experienced with the earlier flagship Toshiba CW34XC2 (Canadian model). In the mean time (since I made the decision to sell) I've gotten a high def PVR and discovered that it's only on low quality SD that the Toshiba is less than satisfactory. Maybe I should keep it and sell the Sony. I got a great deal and shouldn't have any trouble.

When I decided to sell the Tosh I was also a little concerned about the fact that the 34hf83 only used a "wide band" video amplifier rather than the "ultra wide band" amp used on the hfx version. Some people claim this is not an issue. In audio, even though speakers only go up to about 20khz it is desirable to have an amp that goes much higher in order to minimize harmonic distortions (if I understand correctly). I'm not sure the same holds true for video.
That said, the picture on the Sony does strike me as more "vibrant" and "3 dimensional" than the Tosh . (That's after I used the Avia test DVD to back off the red push typical on Sony's.) On the other hand I should note that another real plus with the Tosh is the fact that the geometry is almost dead bang on right out of the box.
I know from experience that sometimes simpler and/or cheaper can be better. ie The original Panasonic RP56 DVD player ( and later the 82) which contained the Farouja deinterlacer chip was not even advertised and yet provided a level of technology that, not only equaled, but surpassed high end players costing 5 to 10 times as much.

Ps Are you sure that Sony isn't driving the TV at 625p? I probably have to think about this some more but I've noticed that on zoomed 4:3 I can see very thin scan lines while on an HD feed the picture is absolutely continuous.

subysouth

11-14-04, 10:39 PM

I'm confused, what Sony do you have?

Without a doubt I would keep the Toshiba.

On the Sony at 625p I am positive its not at that rate, they dont even claim its trying it let alone doing it. [625p would be a significantly higher scanning frequency than 1080i btw.] Scan lines are actually dead space between active lines or the dead space allows you to differentiate the active lines from each other. The gap is the problem no matter which way you look at it. When you zoom in 4:3 you should see the scan lines, you should also see scan lines on 1080i, but you dont. Thats becuase too many lines are trying to be laid in too little space. On 1080i on curent CRTs, not only do they leave no gap they almost fully overlap. Thats another reason the image looks better or fuller, but overlapping it muddies(1st field line info laid over 2nd field line info etc etc) the image.

A progressive image drawn on exaclty the line count the set has gives a full picture without overlap and no gaps between the lines(scan lines.)

Put your Toshiba on 540p for all sources - now. :) That is all.

ss

Dearth

11-14-04, 10:57 PM

Hey is this Gary Merson review in "The Perfect Vision" mag just wrong?

"Right out of the gate, the 34XBR910 wins the resolution race for its size category. This TV boasts a whopping 65% increase in horizontal resolution compared to all previous and current Sony widescreen “standard” direct views, with 1401 horizontally-measured aperture grille slots (see sidebar) in its new “Super Fine Pitch” CRT versus the 847 in Sony’s standard-pitch widescreen tubes. It has higher resolution than competing-brand direct views such as the Sampo 34", which has around 1000 shadow-mask holes. It also exceeds the resolution capability of the highest-resolving plasmas, which have 852 horizontal pixels for 32" and 1024 for 42" screens, and of LCD panels, which currently max out at 1280 horizontal pixels for screens from 30" to 37"."

Now I know that some newer LCDs have even more resolution this article was from late 2003.

http://www.theperfectvision.com/newsletter/tpv51/sony_kv34xbr910.html

subysouth

11-14-04, 11:25 PM

Originally posted by Dearth
Hey is this Gary Merson review in "The Perfect Vision" mag just wrong?

"Right out of the gate, the 34XBR910 wins the resolution race for its size category. This TV boasts a whopping 65% increase in horizontal resolution compared to all previous and current Sony widescreen “standard” direct views, with 1401 horizontally-measured aperture grille slots (see sidebar) in its new “Super Fine Pitch” CRT versus the 847 in Sony’s standard-pitch widescreen tubes. It has higher resolution than competing-brand direct views such as the Sampo 34", which has around 1000 shadow-mask holes. It also exceeds the resolution capability of the highest-resolving plasmas, which have 852 horizontal pixels for 32" and 1024 for 42" screens, and of LCD panels, which currently max out at 1280 horizontal pixels for screens from 30" to 37"."

Now I know that some newer LCDs have even more resolution this article was from late 2003.

http://www.theperfectvision.com/newsletter/tpv51/sony_kv34xbr910.html

Note Gary uses the word theoretical. Slot openings are one of the things that defines horizontal resolution on a Sony set, the others are beam spot size and phosphor triad count. In order for the Sony to have 1400 unique horizontal pixels it would have to have a pitch of .54mm screenwide, which is possible, but would be extraordinary. The info I recall was .68mm. But the easy way to resolve it is to count the seperate phosphor triads visible on the surface of the screen - you dont have to count them all just a measure and multiply it out. If you had the set you could do it in minutes with a slide rule.

I find it curious that Sony lists no specific resolution on any of their data nor lists any pitch size.

ss

jonnyozero3

11-14-04, 11:35 PM

In audio, even though speakers only go up to about 20khz it is desirable to have an amp that goes much higher in order to minimize harmonic distortions (if I understand correctly). I'm not sure the same holds true for video.

I don't know what is recommended in an amp in this regard, but I am pretty sure that if you increase the bandwidth of the amplifier you will actually be accepting MORE harmonics of the original signal in the reciever that is being amplified. This is actually a good thing in theory, as I understand it, since the more harmonics that are "allowed in" the more accurate or true the resulting output signal becomes to the originial input. Note: I am NOT saying that it would be good for a speaker or amp to produce harmonics unless they were there in the original signal in the first place :)

Also, I think the human ear is probably the limiting factor around 20khz rather than the speaker.

Subysouth - you have some great facts and science to back up your opinions info (nice that this is a civil conversation by the way), but if gdg says:

That said, the picture on the Sony does strike me as more "vibrant" and "3 dimensional" than the Tosh

Than I would say, no matter what the resolution debate turns out to be, if he (gdg) had both sets calibrated correctly and running under the same circumstances than either:
A) The sony is indeed the better set, either by resolution or some other factor.
or
B) gdg's eyes are lying to him...:P

No matter which is true, I'd say, don't tell him to get rid of the set that looks the best to him.

Finally, Dearth: the link on the Sony/Sampo comparison is very interesting, seems to disagree quite a bit....

This is fun :cool:

gdg

11-14-04, 11:40 PM

In answer to your question I currently have the Sony kd34xbr960 and the Tosh 34hf83. One will have to go.
There are still 2 things that puzzle me about this discussion.
1) Why would Sony retool and develop an entirely new level of technology if there are no real practical benefits and possibly some drawbacks (overdriving phosphors can't be good in terms of longevity)
2) Why has the 960 received almost universal acclaim as state of the art amoung reviewers. Surely they're not all sucked in by the numbers. Any good reviewer knows that the real proof is in the pudding.

jonnyozero3

11-14-04, 11:49 PM

Note Gary uses the word theoretical

Good catch Subysouth.

So, are you saying that the Sony XBR does indeed have a higher resolution than the Toshiba HFX--but, due to the Sony's mismatch between displayed output resolution and the 1080i input, and the Tosh's closer match at 540p, even at a lower resolution, that the Tosh displays a theoretically (I like that word ;)) better picture?

I have to say, that in my small amount of tv shopping experience I have found the Sony XS and XBR lines to be the best to my eyes. I think I did see some Tosh's but they had terrible geometry problems...these were floor models, of course...I pretty much dismissed them then.

subysouth

11-14-04, 11:58 PM

Originally posted by gdg
In answer to your question I currently have the Sony kd34xbr960 and the Tosh 34hf83. One will have to go.
There are still 2 things that puzzle me about this discussion.
1) Why would Sony retool and develop an entirely new level of technology if there are no real practical benefits and possibly some drawbacks (overdriving phosphors can't be good in terms of longevity)
2) Why has the 960 received almost universal acclaim as state of the art amoung reviewers. Surely they're not all sucked in by the numbers. Any good reviewer knows that the real proof is in the pudding.

It would depend on a lot of things.

Did the reviewer test only using HD 1080i signals at native rate on both sets? The higher inherent resolution of the Sont and lower line overlap would make it look better on 1080i, but IMO neither of them should be driven at 1080i. 540p on the other hand is closer to the Toshibas native rate. Also the Sony with its finer pitch might look subjectively higher res at the same distance. Meaning the two devices shouldnt be viewed at the same distance for a level comparison because one has a smaller pixel. I wouldnt mind seeing acomparo with the 1080i HD input on the Toshiba driving 540p from 8' and the Sony on 1080i at 6'.

gdg is uniquely set up to pull this off...

At my distance - 10', the Sonys resolution advantage is wasted.

So many variables.....

I dont even know where gdg is viewing from for instance. If hes close sub 6' I have no doubt the Sony would probably look better. My computer monitor would make the XBR960 look bad at 3'. Distance is key to the right decision on display device. If I havent said it enough let me say it again.

ss

gdg

11-15-04, 12:00 AM

One other point, regarding how good something looks. My experience with high end audio gear suggests that if one is interested primarily in "Hi Fidelity", then accuracy is the holy grail. Unfortunately, in audio, qualities that attract ones ear, or more importantly one's fancy, are often in reality, at best, deviations from accuracy or, at worst, actual distortions. It seems to be a truism that the more accurate a piece of equipment, the less attention it draws to itself, revealing sources for what they are, both good and bad.
Having said that I would not write off the Toshiba strictly on the basis that the Sony looks better, since as in audio, what attracts the eye is not always what is most accurate, hence the outrageous factory settings boosting both contrast, sharpness and red, to name a few.

Ps I'd like to do a side by side but at the moment I'm alone and can't move the suckers (165 and 199lbs).

jonnyozero3

11-15-04, 12:01 AM

Hmmm, I'm learning some good stuff tonight.

I wouldnt mind seeing acomparo with the 1080i HD input on the Toshiba driving 540p from 8' and the Sony on 1080i at 6'.

I would also be interested in hearing some impressions.

subysouth

11-15-04, 12:02 AM

Originally posted by jonnyozero3
Good catch Subysouth.

So, are you saying that the Sony XBR does indeed have a higher resolution than the Toshiba HFX--but, due to the Sony's mismatch between displayed output resolution and the 1080i input, and the Tosh's closer match at 540p, even at a lower resolution, that the Tosh displays a theoretically (I like that word ;)) better picture?

I have to say, that in my small amount of tv shopping experience I have found the Sony XS and XBR lines to be the best to my eyes. I think I did see some Tosh's but they had terrible geometry problems...these were floor models, of course...I pretty much dismissed them then.

YESSSSSSSSS!

And when viewed at an appropraite distance for each sets pixel size. You shouldnt be viewing a .68mm(assuming thats the Sony's) and .84mm pixel size devices at the same distance. They are built for different distances whether the manufacturer is making that clear or not. Your eyes resolution doesnt vary, so if you vary the pixel you have to vary your distance to be fair. And of course you need choose a device that jives with your viewing distance altogether.

ss

gdg

11-15-04, 12:09 AM

I'm actually between 8 and 10 feet away depending on how far back I lean in my Lazy Boy. That said,what really seems to stand out is the vibrancy of color in the Sony. I'm not convinced that this is better though, since, using the user menu and the Avia disc I still find there's more red "push" than on the Tosh, which can be set (via the user menu) almost dead accurate.

subysouth

11-15-04, 12:15 AM

And just another bit on the Sony's outright resolution. Heres Joel Brinkleys take on the same set:

http://www.ultimateavmag.com/directviewandptvtelevisions/104sony/

He puts his estimate of actual horizontal resolution between 1000-1200 lines. My hats off to Gary if he actually counted the slits in the shadow mask(I guess he dismantled the set?) but if he was that close, why not close the deal with beam spot size and phosphor count. He certainly has the testing equipment at his disposal.

And again why isnt Sony playing this up? If my large fromat set was running a .54mm pitch size, I'd be singing it from the hilltops. On the downside, .54mm would come out pretty dim unless something is being done to boost light output.

Joe Kane was wrestling with properly calibrated light output on the .62mm pitch AF3.0HD. Controlling room light was a requirement not a luxury. Theres a big tradeoff somewhere if Sony's running a .54mm pitch. And again if its .54mm, the average person should be sitting at ~4.5' to get the full resolution. Thats mighty close.

ss

jonnyozero3

11-15-04, 12:20 AM

Ahhh, gotcha. This is so friggin complicated. heh. I still have questions but can't even figure out what's nagging my brain still. Anyhow...

That said,what really seems to stand out is the vibrancy of color in the Sony. I'm not convinced that this is better though, since, using the user menu and the Avia disc I still find there's more red "push" than on the Tosh, which can be set (via the user menu) almost dead accurate.

Quick question: Have you set the color decoder settings on your XBR (in the picture menu, advanced settings) to "monitor" instead of "default". I noticed that this takes out most if not all of the red push. (Checked by eye not by avia). This may be what you mentioned but I wasn't sure.

Can you tell I've spent too much time at the local B&M shops? I don't even own one of these, haha.:p

gdg

11-15-04, 12:28 AM

One thing is for sure, Sony has both, the (technical) ability to excell and, at the same time the lack of scruples to market a BS idea because it serves their purpose. ie They are capable, and have built truely state of the art CD players (top ES models) while at the same time they are pushing a technologically flawed audio format in order to serve their own corporate ends. (won't go into that now)

jonnyozero3

11-15-04, 12:29 AM

Joe Kane was wrestling with properly calibrated light output on the .62mm pitch AF3.0HD. Controlling room light was a requirement not a luxury. Theres a big tradeoff somewhere if Sony's running a .54mm pitch. And again if its .54mm, the average person should be sitting at ~4.5' to get the full resolution. Thats mighty close.

4.5 feet would put you close to THX's recommended viewing angle...
http://www.myhometheater.homestead.com/viewingdistancecalculator.html

Not to sidetrack too much, thought it was interesting. It's also close enough for fully resolved HDTV (which I know these TVs do not do), but I see the basis for your 4.5' measurement.

jonnyozero3

11-15-04, 12:36 AM

SS -

Did you see this (from your ultimate AV mag link)?

"The KV-34XBR910 displays all high-definition programming at 1080i unless its Digital Reality Creation (DRC) scaler is set to Progressive—in which case the display is 540p. Sony recommends using the Progressive setting only for still images and text, such as from a Memory Stick. In any case, 720p high-definition programming is converted to 1080i. In addition, DRC scales 480i signals to 960i"

gdg

11-15-04, 12:39 AM

I have everything set as neutral as possible. VSM off, color temp:neutral, color decoder: monitor etc etc. These settings still resulted in some red push. Hence, I had to bump up color 4 steps and back off the hue by 1. That was as close as I could get and if I remember correctly red still seemed to be bumped up between (5 and 10%). On the Tosh I was able to get less than a 5% deviaton from neutral.

Note: The Avia color and hue calibrations do not appear to be dependent on ones ability to differentiate color, but rather in one's perception of color gradients (vibrating boxes disappear into the backround). I would assume then that individual variations in color perception should not be a factor and I've done the best job without going into service menu.

jonnyozero3

11-15-04, 12:46 AM

Okay, I figured as much. Just thought I would check.

I must say I wish I had those two TVs in my place right now...if I had my house yet I'd take that Sony off your hands, :)

Getting back on track though, I'm waiting with baited breath to see if this 540p quote changes things...

I am also wondering how upconverting DVD players factor into this equation? Better to use 720p or 1080i? Or would it be better to stick with a standard 480p player?

gdg

11-15-04, 01:06 AM

Note that 480i is scaled to 960i. That's what I was refferring to when I said I could see the interlacing dark lines (not as obvious as on a standard TV) but did not see them on the HD sources.

gdg

11-15-04, 01:13 AM

I'm sticking with 480p since I have the Panny RP-82 with the Farouja deinterlacer. It's the motion artifacts that are problematic on 24 frame film converted for TV and that is were the Farouja shines. It's state of the art technology and I can't see any advantage in upconverting. I seriously doubt that the Sony handles 3:2 reverse pulldown better.

gdg

11-15-04, 03:22 AM

I cannot alter the settings I choose such as "interlaced", "progressive" or "DRC" once I'm locked onto a high def signal. That means the set either defaults to 1080i or, once the TV is set for 540p, it cannot be changed on the "fly". I suspect it simply defaults to 1080i and the Toshiba probably does the same since it has virtually the same 3 choices in it's menu.

If, on the other hand, the set can actually be set for 540p on HD sources than I have to wonder whether it incorporate some kind of variable scaling via the user adjustable *DRC mode which, along with progressive 540 option, is one of the 3 choices available in the advanced menu. ie. interlaced (4x density for moving pictures), progressive (4x density for still images and apparently 540p) or USER ADJUSTABLE DRC (for film based material). If the DRC actually incorporates some kind of scaling then the set is a lot more sophisticated than people realize and would explain why Sony reps insist the 960, with it's more advanced DRC, is capable of a better picture than the 955 on ALL sources. I've seen it in the past where the user is given control of a fairly sophisticated aspect of the technolgy, but it is given a dumbed down label and a limited number of choices. For example, if I remember correctly, on the Panasonic RP82 one can actually choose varying degrees of dither in combination different low pass filters. Since it would be useless to explain to the average person what the choices actually mean, the feature is simply called "Remaster" in the menu.

*I havn't explored the DRC and on the surface it appears to incorporate 3:2 reverse pulldown in combination with upconversion (with appropriate source material) and possibly some level of scaling.

gdg

11-15-04, 04:28 AM

Scratch that. On the Toshiba, one can only choose between 540p and 1080i as a "display fomat" when upconverting from 480i.
That appears to be the case on the Sony as well.

Interesting conversation I'm having with myself.;)

Dearth

11-15-04, 07:59 AM

No the Sony displays 480i as 960i or as 540p depending on if you choose interlaced or progressive/cinemotion. I am certain of the 960i the 540p I have seen in a few articles but who knows.

Also Suby that Merson review doesn't have him physically counting the slots but he calculated it using test patterns from the HD DVE source:

"This set upconverts 720p input signals to 1080i so I choose the 1080i version of the tape for my tests. DVE contains an extensive array of test patterns and some original HD content. I concentrated on its multi-burst patterns, which are used to examine HD display resolution capabilities. The top pattern I could resolve was the 22MHz pattern, which by no coincidence matches up to the set’s super-fine picture tube’s 1400+ horizontal resolution."

rickypicky

11-15-04, 10:21 AM

Subysouth,

How many horizontal lines (counted vertically) does my Toshiba 26HF84 have?

How many vertical lines?

PaulGo

11-15-04, 10:36 AM

Originally posted by gdg
Scratch that. On the Toshiba, one can only choose between 540p and 1080i as a "display format" when upconverting from 480i.
That appears to be the case on the Sony as well.

Interesting conversation I'm having with myself.;)

According to my manual the Toshiba (30HF83) 540p will work only with a 480p source not a 480i source. The 480i gets converted to 1080i.
This is confirmed with my observations where the 540p/1080i switch in the menu only works with a 480p source (such as a progressive scan DVD or my Motorola 6200 HD cable box where the 480i signal is changed to 480p - the HD signal is output at 1080i).

rickypicky

11-15-04, 10:57 AM

rd001

11-15-04, 12:31 PM

Originally posted by subysouth

I find it curious that Sony lists no specific resolution on any of their data nor lists any pitch size. Exactly. If Sony is so superior, this should be the first selling point in their marketing info.

If they do enjoy such an overwhelming advantage, why are they so quiet about stating it in writing, the kind of statement that could be tested later in a class action lawsuit if it turned out they were 'fibbing'.

Love your posts.

montreal

11-15-04, 01:08 PM

Originally posted by rd001
If Sony is so superior, this should be the first selling point in their propaganda marketing info.

Well they actually did that in their press release when they introduced the XBR910. They stated the aperture grill pitch in millimeters as measured at the center and at the edge of the screen and when I compared these specs to my 34XBR800 which I measured at about 850 sets of slots, it was apparent that the newer super-fine pitch grill had over 1400 slots.

Nevertheless, it is obvious that Sony and the others don't want to make or break their sales success by focusing only on one important and measurable feature whose advantage is at the mercy of so many other factors outside the TV set.

The problem is that to fully benefit from the finer pitch, you need to receive a signal via OTA coming live from a HD-CAM in the studio.

When you have a signal that has been prerecorded and later transmitted using compression, I doubt if you will be able to truly appreciate the capability of the 1400 horizontal resolution.

When we start getting HDDVD's in the future, then many of you will be glad you chose a 1400 pitch Sony back in the year 2004. I wish these sets had been available 2 years ago.

Also, don't compare audio resolution and video resolution. With video, you can physically approach a screen to see more detail if its available. With audio, for a fixed decibel level, there is no way to force your ears to better hear high frequencies after you've cleaned out all the ear wax.

rd001

11-15-04, 01:41 PM

Originally posted by montreal
[B]Well they actually did that in their press release when they introduced the XBR910. They stated the aperture grill pitch in millimeters as measured at the center and at the edge of the screen and when I compared these specs to my 34XBR800 which I measured at about 850 sets of slots, it was apparent that the newer super-fine pitch grill had over 1400 slots.
...
The problem is that to fully benefit from the finer pitch, you need to receive a signal via OTA coming live from a HD-CAM in the studio.
...
When you have a signal that has been prerecorded and later transmitted using compression, I doubt if you will be able to truly appreciate the capability of the 1400 horizontal resolution.
Interesting points.

I'd like to see Sony state explicitly that their high-end fine-pitch tubes actually resolve and display these 1400x1080 pixels. This should be a verifiable fact. And yet, they don't seem to claim it.

Let them put it in writing. And the fact that they made the claim for the XBR910 but have since apparently backed off the claim for subsequent models would indicate to me that they are concerned about false advertising liability.

Sony has told more than a few fibs in its marketing history.

dt_dc

11-15-04, 01:55 PM

Originally posted by Dearth
No the Sony displays 480i as 960i or as 540p depending on if you choose interlaced or progressive/cinemotion.The Sony sets have 480p, 960i, and 1080i native scan rates. 480i input is converted to 480p for display if DRC is set to progressive or cinemtion. 480i input is converted to 960i if DRC is set to interlaced.

At least, that's the way the 800s / 900s worked.

I hadn't seen anything about Sony going the 540p route (like Toshiba).

montreal

11-15-04, 02:52 PM

Originally posted by rd001
I'd like to see Sony state explicitly that their high-end fine-pitch tubes actually resolve and display these 1400x1080 pixels. This should be a verifiable fact. And yet, they don't seem to claim it.

There are many parameters of a TV set that are difficult for a layman to measure. The aperture pitch is not one of these. Anyone can take a ruler and a magnifying glass and count the number of red stripes that traverse an inch's worth of ruler and then estimate the number of red stripes that span the full width of the CRT.

All HD ready sets resolve and display 1080 lines vertically. Each transmitted line is discreet.

Can a high-end fine-pitch tube resolve and display 1400 pixels horizontally?

Of course it can because the electronics have a video bandwidth of over 30 mhz. and if your goal was to turn on every second pixel of the 1400 while scanning horizontally, then you would only have to feed the CRT gun with a 23 mhz sine wave, this being well within the set's capabilities.

23 mhz is calculated by allocating one cycle of sine wave for every 2 pixels horizontally, so 1400 divided by 2, times the horizontal scanning frequency of 33 khz gives approximately 23 mhz. Most HD analog signals leaving a STB rarely do better than 15 mhz, slightly better than progressive DVDs at 13.5 mhz.

Additionally, the electron beam has to be focused sharply enough to only illuminate an area of phosphor about a half a millimeter by a half a millimeter. When Sony first introduced their high pitch tube, they also advertised the fact that their electron guns had sharper focusing than previous generations.

In my books, the XBR960 has all the cookies to deliver a 1400 by 1080 image, and then some.

subysouth

11-15-04, 04:58 PM

Originally posted by jonnyozero3
SS -

Did you see this (from your ultimate AV mag link)?

"The KV-34XBR910 displays all high-definition programming at 1080i unless its Digital Reality Creation (DRC) scaler is set to Progressive—in which case the display is 540p. Sony recommends using the Progressive setting only for still images and text, such as from a Memory Stick. In any case, 720p high-definition programming is converted to 1080i. In addition, DRC scales 480i signals to 960i"

I did and had various thoughts about it.

Take the Toshiba set using a dot mask and having a res somewhere near 960x540, if you run that at 540p youre golden.

The Sony on the other hand while moving closer to 1080i slightly with their fine pitch screen has moved farther off 540 vertical lines, a regular rate. Lets call the Sony 625 vertical for arguments sake. If you run 540p on a screen with 625 vertical lines you are now gonna see those 85 dead lines if youre close enough. I think thats why Sony is not encouraging it. On the Toshibe you will see few if any dead lines at 540p, but you need to sit farther back.

Sony has moved the viewer closer and moved the actual line count into no-mans land with the super fine pitch screen IMO. They need to define its native rate and run everything to it progressively. No screen can do both 480p and 1080i well, it doesnt work like that.

ss

subysouth

11-15-04, 05:04 PM

Originally posted by montreal
There are many parameters of a TV set that are difficult for a layman to measure. The aperture pitch is not one of these. Anyone can take a ruler and a magnifying glass and count the number of red stripes that traverse an inch's worth of ruler and then estimate the number of red stripes that span the full width of the CRT.

All HD ready sets resolve and display 1080 lines vertically. Each transmitted line is discreet.

Can a high-end fine-pitch tube resolve and display 1400 pixels horizontally?

Of course it can because the electronics have a video bandwidth of over 30 mhz. and if your goal was to turn on every second pixel of the 1400 while scanning horizontally, then you would only have to feed the CRT gun with a 23 mhz sine wave, this being well within the set's capabilities.

23 mhz is calculated by allocating one cycle of sine wave for every 2 pixels horizontally, so 1400 divided by 2, times the horizontal scanning frequency of 33 khz gives approximately 23 mhz. Most HD analog signals leaving a STB rarely do better than 15 mhz, slightly better than progressive DVDs at 13.5 mhz.

Additionally, the electron beam has to be focused sharply enough to only illuminate an area of phosphor about a half a millimeter by a half a millimeter. When Sony first introduced their high pitch tube, they also advertised the fact that their electron guns had sharper focusing than previous generations.

In my books, the XBR960 has all the cookies to deliver a 1400 by 1080 image, and then some.

Either you have good knowledge of the workings of a CRT and have an agenda or you have a passing knowledge of CRTs all together.

Everything you just said is about 1/4 of what it takes for a CRT to define visual info. All that is lumped under scanning. I for one and I dont think anyone else here disputes the Sony is scanning the full 1080i HD signal it is receiving. That doesnt mean its displaying it.

Scanning the lines to the screen discretely doesnt mean they will be displayed discretely. One in no way, shape, or form, guarantees the other.

Care to dispute that?

ss

subysouth

11-15-04, 05:08 PM

subysouth

11-15-04, 05:12 PM

Originally posted by PaulGo
According to my manual the Toshiba (30HF83) 540p will work only with a 480p source not a 480i source. The 480i gets converted to 1080i.
This is confirmed with my observations where the 540p/1080i switch in the menu only works with a 480p source (such as a progressive scan DVD or my Motorola 6200 HD cable box where the 480i signal is changed to 480p - the HD signal is output at 1080i).

Allegedly the newest 34HF and HFX84 allow 540p output on any and all sources. 480p, 1080i, 720p. IMO that feature cant be overstated in importance.

That is the kind of output that is very appropriate to these screens. I cant speak to the 83 series, I am going by the Toshiba website on current models.

ss

Dearth

11-15-04, 06:02 PM

Originally posted by subysouth
Either you have good knowledge of the workings of a CRT and have an agenda or you have a passing knowledge of CRTs all together.

Everything you just said is about 1/4 of what it takes for a CRT to define visual info. All that is lumped under scanning. I for one and I dont think anyone else here disputes the Sony is scanning the full 1080i HD signal it is receiving. That doesnt mean its displaying it.

Scanning the lines to the screen discretely doesnt mean they will be displayed discretely. One in no way, shape, or form, guarantees the other.

Care to dispute that?

ss

If anyone seems to have an agenda it is you. Nearly all of your posts come off as very anti-sony I mean no CRTs display full HD, how recent are the LCDs that can do 1920? I dont' see what the big dispute is Sony's super fine pitch has 1401 slots... like you say it is up to debate if that is utilized properly yet you keep pulling some heresay numbers out that lead you to believe that it has ~1100.... who cares most the sets you seem to favor like the Tosh don't have nearly that many and are more in line with the older sony xbr 847 lines.

Put that Tosh side by side with the xbr960 or any available TV set that is under ~$5,000 and assuming both are properly calibrated (which is critical) the sony will destroy the others.

Have you seen a properly calibrated 960... of for that matter how about your darling Tosh or is it that because you think it might do 540p that it might somehow better suit a 34" set so it MUST look better.

You can only do so much figuring with a pencil and paper go out there and preview a few sets like they do in the mags.... then realize why everyone gushes over a properly calibrated 910 or 960 even over the vaunted older Sampo.

There isn't some huge conspiracy, if a JVC or a Panny or Toshiba had a picture as good as the fine pitch sonys it would be all over the place. Sure sony is pricey but in the case of the fine pitch sets you get most of what you pay for as the best direct view TV picture and the best TV picture period for anything within a few thousand dollars.

subysouth

11-15-04, 06:13 PM

Originally posted by Dearth
If anyone seems to have an agenda it is you. Nearly all of your posts come off as very anti-sony I mean no CRTs display full HD, how recent are the LCDs that can do 1920? I dont' see what the big dispute is Sony's super fine pitch has 1401 slots... like you say it is up to debate if that is utilized properly yet you keep pulling some heresay numbers out that lead you to believe that it has ~1100.... who cares most the sets you seem to favor like the Tosh don't have nearly that many and are more in line with the older sony xbr 847 lines.

Put that Tosh side by side with the xbr960 or any available TV set that is under ~$5,000 and assuming both are properly calibrated (which is critical) the sony will destroy the others.

Have you seen a properly calibrated 960... of for that matter how about your darling Tosh or is it that because you think it might do 540p that it might somehow better suit a 34" set so it MUST look better.

You can only do so much figuring with a pencil and paper go out there and preview a few sets like they do in the mags.... then realize why everyone gushes over a properly calibrated 910 or 960 even over the vaunted older Sampo.

There isn't some huge conspiracy, if a JVC or a Panny or Toshiba had a picture as good as the fine pitch sonys it would be all over the place. Sure sony is pricey but in the case of the fine pitch sets you get most of what you pay for as the best direct view TV picture and the best TV picture period for anything within a few thousand dollars.

Whoa there pal. You might want to back up a couple of steps before trying to put words in my mouth.

No where have I said Sony is unique in exaggerating their sets abilities. I have said as much about all the "HD" CRTs. If you think so, you havent read enough of my posts to be expressing an opinion. I am a multi-brand turner-outter. The topic of this thread happens to be that Sony set.

The above poster is demonstrating some knowledge about CRTs then staing "if its scanning it, its resolving it." I stand by my statement. Either he just doesnt know or knows and has an agenda.

None of these sets can do anything approaching HD. Sony is closest because of their finer pitch screen, but how you use what resolution you have trumps outright resolution. If you dont understand this I am sorry. The Sony is also going to look better closer, which sways peoples opinions on quality. Unfortunately that smaller pitch size is wasted unless you are sitting close in your regular viewing setting. I dispute that the Sony will destroy any other CRT PQwise at any distance.

I dont dislike Sonys, I dislike misinformation. There are 2 sony CRTs within 7 feet of me right now. I am typing this message on a Sony CRT. Your attack is groundless.

You a sensitive 960 owner perhaps?

Huge conspiracy is in the eye of the beholder I guess. If you think its appropriate that last year Sony et al were selling "HD" 1080i sets with ~850-900 horizontal res, thats cool. I personally dont like that approach. I guess what you dont know cant hurt you.

ss

Dearth

11-15-04, 06:39 PM

My post was made tongue in cheek, I don't take you for a Sony hater by any means. You say that you dislike misinformation but most of the posts I read from you, you like to muddy the waters with fuzzy math and mainly here-say.

I have no doubt you probably actually know much more about CRTs than I do but I'm not sure why you go around urinating in our cheerios when people ask questions about the super fine pitch Sonys :)

I agree that CRTs aren't giving you the full HD but no one does it better than the super fine pitch Sonys and yes I have a 910 over in the corner and am staring at an old E500 as we speak as well.

Do you not agree that it is clear the best 34 inch CRT picture is the Super fine pitch sony hands down? You seem to agree but again you like to tweak people who have read the reviews and seen for themselves the outstanding picture these sets have.

I don't think there is anything within a couple thousand of a 960 that has a better picture.

If someone starts a thread asking what is the best 34 inch direct view there really shouldn't be much of an argument... now if he wants to sit 11 feet away he can save some money or if he has a budget then OK I like the Tosh set second best after the three Sonys but it is distant to the super fine pitch sets.

Overall I enjoy your posts since you call people on misinformation. The reason people find you intriguing is that you use some here-say pitch numbers from somewhere and hold onto them like they are gospel, pretty much ignoring magazine reviewers who test using multi-burst patterns. Then, on the other hand you belittle other people as having a lack of knowledge (which many admittedly do) and/or having an agenda which is a pretty stiff accusation and one you clearly didn't like having reflected back to you.

Addressing your edit about the old sonys having about 847 lines... yeah and they still do and so do many of the shadow masks etc. That isn't some big revelation the super fine pitch is a 65% improvement over the old admittedly low number of ~850. The sampo is quoted as having 1000 shadow mask openings a great number for its time and still very competitive with most direct view CRTs from any manufacturer.

subysouth

11-15-04, 06:59 PM

I admitted several weeks ago I couldnt re-verify my info on the pitch of these screens but I have a weird memory with numbers. I was told it was .68mm and it would have been someone in the biz I would have believed. You dont have to believe it though. Barring montreal(which I hope he does) producing this Sony press release I am gonna go with what I remember.

The point is my take at .68mm is pretty reasonable against what I know about CRTs. Thats a very fine pitch in itself, unheard of in a large format set(most were about .9mm.) The needed pitch to pull off 1400 actual horizontal res is incredible in a large format set.

I dont agree the Sony is the clear winner. There so many variables in there. [Lets ignore color which btw CNET found bad in two parameters on the Sony after calibration.] Sticking to the screen res usage issue, the line overlap is muddying the picture(as it is on all the current "HD" crts trying to do 1080i.) The Sony will likely look better closer than any of the other sets because pixelization will outweigh the muddying issue. You cant compare this Sony set straight up with another set a any set distance - well you could but it wouldnt be helpful. The Sony's finer pitch is wasted further away but is better up close. Like I said in the other thread I would like to see a calibrated comparo of a Toshiba 34" at 8' on 540p vs a XBR960 at 6' with 1080i. Thats a reasonable comparo. I think you might find the results suprising. Not because it has better resolution but its using it better.

Sub 6'(where most people view sets in stores) the Sony's gonna win due to its finer pitch.

All that I can agree to and no harm no foul.:)

I guess what I am saying about Sony and all other manufacturers is if they were selling sets that needed to do 1920x1080i that they knew were doing 847h x unknownv, why do you believe them now. The set may well have 1401 slots, that doesnt mean its doing 1400 actual resolution. They dont even claim it does if you read it. They handily avoid stating actually resolution. You think they dont know it?

ss

Joxer

11-15-04, 08:36 PM

The Toshiba can only produce 540p from a 480p input. 480i, 720p, and 1080i can only be displayed at 1080i on the Toshiba.

gdg

11-15-04, 08:37 PM

I'm no engineer so you'll have to forgive any misuse of terms. It seems to me that if you think about it, trying to scan a higher frequency (resolution) signal onto a lower resolution display is problematic (vertically anyway). A simple diagram superimposing say 4 lines onto 3 illustrates the problem. It seems to me that unless the the vertical scanning frequency/resolution is an integer multiple of the screen resolution one will not be able to realize the full potential of the display. In fact if this multiple relationship does not exist I would hazard to say that, in practical terms, one will actually get lower overall resolution by going to a higher resolution display (if it is not an integer factor of the scan resolution). If I am conceptualizing correctly one will lose real info and at the same time get redundant duplication as a result of redraw. That's utterly ridiculous and I can't believe Sony would do something that stupid just to say they have better specs.
That said, I cannot believe the issue is that simple. It seems to me that Sony could easily claim to accept 1080i (thus HD) and then downconvert/scale to the native resolution of the display in order to scan at that resolution. Why would some of the most advanced engineers on the planet do something so obviously stupid as the try and scan 1080 lines onto 650 (or what ever it is)? As SS says, that would result in less actual displayed information than if they just stayed with 540 lines vertically. Something doesn't jibe here. Sure companies like to play with specs, but at the expense of actual performance? That's just silly and while some people do get sucked in by specs, the average Joe, still buys a Sony because they perceive a real performance advantage.

gdg

11-15-04, 08:47 PM

Sony may not state it's actual resolution but who does?
Also, I seriously doubt that the new Toshiba has made the fairly significant change of allowing selectable 540p on all sources when on previous sets it only allowed this when upconverting 480i. This is very clear on the hf83.

subysouth

11-15-04, 10:54 PM

Your are starting to see the illogic of doing this, but think also of how an engineer is supposed to make a tv that supports current 480i, 480p and at least one HD source, in this case 1080i, becasue its an easier scan rate.

The HD standard is putting all the CRT direct-view manufacturers against the wall, not just Sony. The CRT technology itself is not very HD friendly, they are running out of gun speed trying to perform HD on large format sets. But lots of buyers for good reason favor the CRT for its natural PQ. The system is backing them into a corner. You are unlikley to see HD on a direct view CRT the size requiring even 720p let alone 1080i. But they cant do 720p cause it would be difficult to scan and blatant overlap, worse even than interlaced overlap PQ wise.

As I posted earlier in the thread, the shadow mask hole count on Panasonics $6500 1st gen 480p/1080i 34" set is precisely 1118 x 611. This info can be found in WSR. That was the absolute limit that the resolution could be(like the Sony it could be less) and that set was being sold as a 480p/1080i set. How do you figure Panasonic is gonna pull off 1920x1080 with only 1118x611 holes? Theres only one way to do it - line redraw.

Maybe Sony has refined its screen to 1400x1080 distinct pixels in 4 years. It would require a .39mm beam spot size in addition to a screen wide .54mm pitch. I suppose anything is possible. I am gonna remain in the skeptic camp until I see some better evidence.

ss

subysouth

11-15-04, 11:02 PM

Originally posted by Joxer
The Toshiba can only produce 540p from a 480p input. 480i, 720p, and 1080i can only be displayed at 1080i on the Toshiba.

And I quote from Toshibas website on the 34HF84:

Crystal Scan HDSC upconverts all video signals to (including 480i/p) to 1080iHD resulting in a significant reduction in jagged line artifacts creating the sharpest, most realistic picture from every source. For users who want to display a progressive image from a progressive scan source, selectable 540p is available via the on-screen menu.

Another part says:
CrystalScan HDSC™ (All time 1080i) with User Selectable 540p

SEBcanadaceo has the set and says he has 540p selected for everything except his vcr IIRC. Check his thread on the 34HXF84 and Toshibas site for more info.

ss

gdg

11-15-04, 11:24 PM

My question for an engineer would be "does the Sony actually scan at 1080i or is the source signal scaled down to the resolution of the TV?"
Since 1080i is the standard (not variable) it would require a fairly simple mathematical algorithm to scale to whatever the native res is. That said, I'm still skeptical that this isn't being done since, as evidenced by most reviewers, the consensus seems to be that the Sony picture actually is superior (which according to this debate it shouldn't be). If this is what is happening they are surely not going to confuse the issue and the consumer by advertising it, even if it is the right way to go.

jonnyozero3

11-15-04, 11:51 PM

subysouth

11-16-04, 12:02 AM

Originally posted by gdg
My question for an engineer would be "does the Sony actually scan at 1080i or is the source signal scaled down to the resolution of the TV?"
Since 1080i is the standard (not variable) it would require a fairly simple mathematical algorithm to scale to whatever the native res is. That said, I'm still skeptical that this isn't being done since, as evidenced by most reviewers, the consensus seems to be that the Sony picture actually is superior (which according to this debate it shouldn't be). If this is what is happening they are surely not going to confuse the issue and the consumer by advertising it, even if it is the right way to go.

I think viewers are subjectively rating higher because it does better with a 1080i feed than other 34" sets and it has finer pixels so it looks better close.

If the tests are limited to 1080i, the Sony is going to win hands down, even if its not the best way to drive the set.

You should see the glowing reviews WSR gave the Panasonic set I mentioned above. It was better than anything they had seen(including Sony's 34" set for that year.) It doesnt mean it couldnt be better if it were driven appropriately.

Again I would like to see a different test. How about the Sony vs the Toshiba at 540p or a Sampo at a custom res off a HTPC and at approprate distances for each set.

Its a lot easier and lees dangerous for Sony to claim theyre doing 1080i than to resample to the sets inherent resolution. If they are doing a legitmate 1080i, what are the 600 other lines doing on 480p?

ss

gdg

11-16-04, 12:37 AM

As noted before one thing I've noticed on the Sony is that on 480i source, no matter how I set my TV (progressive or DRC) I can easily see the scan lines which I couldn't on the Tosh. That confuses me, since at the very least the Sony should be upconverting to 960i and I wouldn't expect to see lines at that scan rate. At least that explains what's happening to the other 600 lines on 480p....nothing!
Ps As noted, on HD no lines whatsoever (what gives, the difference between 1080i and 960i isn't that much) ?

gdg

11-16-04, 01:30 AM

Be carefull how you interpret the menu/specs. On my Tosh 34hf83 I can select 540p but that doesn't mean that it works on all sources just because it's selected. It's my impression that the set defaults to 1080i on HD. Note SEB talks about his DVD (480) in particular and that's no big deal.
I don't see anything on the Tosh website that makes it clear that one can set this all sources.

So what's the consensus here? Can the 83 and/or 84 do 540p on all sources?

PaulGo

11-16-04, 09:57 AM

'So what's the consensus here? Can the 83 and/or 84 do 540p on all sources"

Absolutely not as I have stated above - it only does the conversion on 480p as it is clearly stated in the manual and verified by observation on doing the switch on a 480p source vs a 480i source or HD 1080i source.

From the advertising specs from my set:

"CrystalScan HDSC™ upconverts all video signals (including 480i/p) to 1080i HD. This results in a significant reduction in jagged-line artifacts which produces a smoother, more natural image. Selectable 540p, for users who want to display a progressive scan image from a progressive scan source, is available via the on-screen menu"

From the 30HF83 manual:

"The DISPLAY FORMAT feature is available only for 480p input. 1080i is always output when a signal other than 480p is input. If you notice flickering in a 480p image, try setting the DISPLAY FORMAT to 540p."

montreal

11-16-04, 11:48 AM

With aperture grills (like the Sony) , the phosphor stripes run continuously down the screen and the vertical amplifier can place the scan lines closer together or farther apart because the vertical resolution is infinite as long as the focus of the beam is infinitesimal. In reality, beams are not perfectly focused and horizontal lines may blend together. Indeed, 4:3 format TVs do this with vertical compression for anamorphic DVDs and it is the TVs with aperture grills that do this compression best. I've never heard anyone complain that their vertically compressed image is bad because the lines melt together by being so close.

Now horizontal resolution is a different matter from vertical resolution. Where vertical resolution is clearly related to discrete vertical scan lines, traditionally, the horizontal line has always been treated as a continuous analog wave and black and white TVs simply modulated the electron beam to mimic the original analog wave coming out of the studio camera.

Modern HD studio cameras which use CCD arrays generate a series of numbers that try to mimic the analog signal of older days because numbers are easier to store and transmit in today's world.

Just as in the world of audio where the analog signal is golden, so much that there is a war on between which hi-res audio format (SACD/DVD-AUDIO) approximates best the original analog audio signal, so is it the same in the video world.

All this to say that the best horizontal signal is an analog one.

This means that slicing the horizontal line up into 1920 parts is better than slicing it up into 1280 parts. It is the job of the TV's electronics to take the 1920 parts and try to construct an ideal analog waveform and all HD sets will do this fairly well. A problem arises when its time to deliver the analog waveform to the inside surface of the CRT coated with a phosphor pattern.

Imagine separating a 35 mm. photo slide into 3 transparencies of primary colors. Then imagine slicing each transparency into 1400 vertical stripes. Then imagine taking the 4200 pieces of celluloid and arranging them all side by side in a sequentially repeating order of RED, Green, and BLUE. You end up with a image which is 3 times as wide as the original slide , but you can correct for this if your original photo was proportionally shrunk with a special lens. It is obvious that the end result is going to look cleaner as the width of each celluloid stripe becomes narrower.

It is not an issue if the original camera shot the 35 mm. slide photo through a screen door that had 1920 holes across. We just make sure that the 1920 horizontal elements melt together during the development process before we re-slice each transparency into 1400 new elements. The TV does this melting electronically.

The point is that 1920 pixels helps you more horizontally than 1280 and 1400 aperture grill slits helps you more horizontally than 850.

Because the TV electronics take numeric pixels and make them analog and then project the continuous analog signal back onto a pattern of discrete phosphor areas, it is less important how the numbers relate mathematically and more important that they have as high a numeric value as possible.

dt_dc

11-16-04, 12:03 PM

Originally posted by gdg
As noted before one thing I've noticed on the Sony is that on 480i source, no matter how I set my TV (progressive or DRC) I can easily see the scan lines which I couldn't on the Tosh. That confuses me, since at the very least the Sony should be upconverting to 960i and I wouldn't expect to see lines at that scan rate.Difference between a shadow mask and an aperture grill ...

Yes, when the Sony is displaying 480p or 960i you can see (if you're close enough) some space between the scan lines. You wouldn't think there's that much visible difference between 1080i and 960i ... but ... there is. For the scan lines to not overlap in 1080i ... there's got to be some space between them at 960i and 480p. On an aperture grill ... you're going to be able to see that space.

dt_dc

11-16-04, 12:54 PM

Re: Digital scaling to match CRTs aperture grill / shadow mask prior to display

You're kidding me right?

Digital scaling to match the display has to be done for a fixed panel.

Doing so for a CRT would have horrendous results. If geometry or convergence is the slightest bit off ... it's going to be downright unwatchable.

You want as accurate a picture as possible (true to the original source) behind the grill / mask. After that ... you have to accept the limitations (and benefits) in front of the grill / mask.

Compounding the limitations / artifacts of digital scaling with the limitations / imperfections of a CRT ... putting in an uneeded A -> D -> A for 480p and 1080i component input ... throwing away the benfits of analog scaling (and there are some) over digital scaling ... not being able to take advantage of the benefits of digital scaling (and there are some) over analog scaling ...

You're kidding me right?

rd001

11-16-04, 01:43 PM

Originally posted by montreal
Well they actually did that in their press release when they introduced the XBR910. They stated the aperture grill pitch in millimeters as measured at the center and at the edge of the screen and when I compared these specs to my 34XBR800 which I measured at about 850 sets of slots, it was apparent that the newer super-fine pitch grill had over 1400 slots.

I located what seems to be the original Sony press release on the XBR910.

SONY DEVELOPS HIGHER RESOLUTION FD TRINITRON WEGA TVS FOR PREMIUM CRT PICTURE PERFORMANCE (http://news.sel.sony.com/pressrelease/print/3065)

Of interest in the following:Created especially for displaying high resolution pictures like high-definition broadcast, the new Super Fine Pitch CRT features the proprietary Super Fine Pitch Aperture Grill with 65 percent increased number of vertical "slits," which improve image resolution, for crisp, brilliant, highest picture quality reproduction from corner to corner.

Together with a new electron gun and high intensity luminescent phosphor, the Super Fine Pitch CRT delivers exceptional picture performance. The improvement is immediately noticeable, with no visible vertical lines on the screen and higher resolution to all corners.

Given your premise that the earlier Sony tubes had 850 slots, we can readily see that 850*1.65=1402.5. Let's call it the 1401 'pixels' that is claimed for the Fine Pitch tubes.

Anyway, the mention of 'corner to corner' and 'higher resolution to all corners' begs the question of the precision of the earlier Sony models in accuracy of reproductioin as one moves toward the corners of the display. It seems impossible to disregard these two distinct mentions of the merits of the Fine Pitch tubes without reflecting on what it tells us about previous Sony tubes and those which are offered on Sony's current non-XBR CRTs.

So, are the phosphors and the slots of the non-XBR Sony's producing their finest resolution only toward the center of the screen? As one approaches the edges of the screen, are there fewer phosphors or less accuracy in the electron gun? That seems to be what Sony is hinting here, though never saying directly.

And this, it would seem, would directly impact on the quality of Sony's current offerings that are non-XBR sets, which are also pretty high priced when compared to some competitors. So it seems to me that even if we grant the Sony XBR's their 1401 pixels horizontally and ignore any overscan (at 5% overscan, for instance, that would be 70 pixels not visible), the discussion still does bear directly on the quality of the entire Sony product line and the value of each unit as compared to its price.

So the suggestion some have made about Sony in some way protecting its high-end line by shading its marketing information might actually instead indicate that Sony is actually shielding the deficiencies of its non-XBR offerings.

The press release also suggests pretty directly that the advantage of the XBR is primarily in high-bandwidth OTA signals, something that should represent the true value of the product as compared to its price and that of its competitors like the Toshibas. Your remarks about the merits of an XBR purchase now becoming more of an advandtage when we get HD-DVD are worth discussing but we don't know when that is, how much the players will cost, how quickly we'll see a substantial library of video offered in this format. And we don't know what will be happening in the meantime to SED, LCD and plasma in price or resolution. For many people, like me, who are looking to get an HDTV now but regard it as almost inevitably an intermediate HDTV step while waiting for prices to stabilize and the offerings of HDTV in cable/satellite/OTA/DVD/HDVD to improve, the XBR may offer substantial benefit now or it may be significantly overpriced for the uses many buyers might be seeking in their own actual usage and given their own viewing setup and personal viision ability.

At any rate, I'm saying that even granted the most generous reading of Sony's claims, you really do need to have sound reasons to pay the premium for Sony 's XBR Fine Pitch. At present, that would seem to be the very highest bandwidth from sources like OTA or perhaps Voom or Showtime HD. But ordinary HD cable offerings and many HD satellite broadcasts clearly would not benefit. And, depending on your DVD player, it may not benefit them greatly either over less expensive models.

Well, I've written too much and said too little but wanted to press these points of dollar value and usefullness of the present video signal sources. It seems to me that this is the real question: resolution vs. price vs. performance in current signals vs. viewing distance vs. viewers' vision.

rd001

11-16-04, 02:04 PM

Originally posted by montreal
Modern HD studio cameras which use CCD arrays generate a series of numbers that try to mimic the analog signal of older days because numbers are easier to store and transmit in today's world.Excellent points. The question then becomes: how many broadcast or fixed media sources are available currently that take advantage of the (granted) higher resolution of the Sony XBR Fine Pitch CRTs.

It would seem that the cost of these Fine Pitch Sonys might be more justifiable in the future than at present. That is, if LCD or plasma or Samsung's offerings don't equal or exceed it in price-performance in the meantime.

It again comes down to how much content is actually available to justify the premium price, even assuming that you are seated close enough and have good enough vision to appreciate the Fine Pitch CRT's resolution.

For many viewers and many pocketbooks, it doesn't add up to automatic value in the Sony. Still, it seems its reputation in the Fine Pitch units has some merit but only so long as you have content which actually utilizes the XBR's higher resolution. And at present, the threads which detail the current OTA and other offerings don't offer great hope that Sony's premium picture will be fully utilized. You have to use that resolution to justify paying the premium price.

It's much the same thing as if I went out to buy an 8000x8000 pixel video card. What use, other than bragging rights, would it be without an affordable monitor to display it on?

montreal

11-16-04, 02:11 PM

Originally posted by rd001
I located what seems to be the original Sony press release on the XBR910.

SONY DEVELOPS HIGHER RESOLUTION FD TRINITRON WEGA TVS FOR PREMIUM CRT PICTURE PERFORMANCE (http://news.sel.sony.com/pressrelease/print/3065)

. [/B]

Here's a excerpt from the Sony Press release that stated the pitch in millimeters. It's from the Sony Asian site and was published when the fine-pitch tube went to market in Asia 3 years before arriving in North America. What they call a 36" and 32" diagonal tube is what we call 34" and 30" respectively.

http://ne.nikkeibp.co.jp/english/2000/08/0828sony_dtv.html

"According to Sony, the number one selling point of its new product lineup is the high picture quality. The receiver unit is equipped with super fine pitch FD Trinitron. The center pitch of conventional receiver units used to be 0.77mm for 36-inch TV and 0.65mm for 32-inch TV. For the new products, however, the center pitch was made 0.47mm for 36-inch TV and 0.42mm for 32-inch TV, as a result of which the number of horizontal slits has increased by approximately 60%. The corner pitch has also been changed from 0.97mm to 0.61mm for 36-inch TV and from 0.90mm to 0.58mm for 32-inch TV. The image output circuit is compliant with 30MHz. On the audio side, the new products will realize Tru Surround function using six three-way speakers."

Not mentioned here is the fact that the narrow focus gun that Sony had been using on their high end CRT RPTV migrated to the new DA-4 chassis that hosted the new fine-pitch tubes. They knew that to target a 0.47 mm. wide pixel, they would need to replace the traditional guns on the XBR800.

Originally posted by rd001
The question then becomes: how many broadcast or fixed media sources are available currently that take advantage of the (granted) higher resolution of the Sony XBR Fine Pitch CRTs.

Video bandwidth gives you crispness, that being the time it takes for the gun to go from full off to full on. This has nothing to do with pitch. It just means that you can have two adjacent pixels side by side and in the time it takes the gun to scan from one to the next, the gun can go from off to on.

When you make the pitch finer, it allows the viewer to approach the screen to notice details that he can't see from further back. Given two identical sets with the same video bandwidth but different pitches, at a certain distance (say 8'), the eye will see identical crispness and identical detail, so unless you plan to view from 4 to 6 feet, pitch won't make a difference.

As time goes on, we are going to acquire signals with higher detail, so even if today, the bandwidth ceiling of the source is at say 18 mhz, when it eventually passes 23 mhz. on the way to 32 mhz., the XBR960 will be realizing its full potential.

dt_dc

11-16-04, 02:53 PM

Originally posted by rd001
Anyway, the mention of 'corner to corner' and 'higher resolution to all corners' begs the question of the precision of the earlier Sony models in accuracy of reproductioin as one moves toward the corners of the display. It seems impossible to disregard these two distinct mentions of the merits of the Fine Pitch tubes without reflecting on what it tells us about previous Sony tubes and those which are offered on Sony's current non-XBR CRTs.. All Direct View CRTs have problems towards the edges ... and even more problems towards the corners. Sony or otherwise ... that is inherent in the technology. Any engineer designing a new CRT ... Sony or otherwise ... is going to attempt to improve performance on the edges / corners (or at least mitigate the problems).

This year's Hondas have better gas milage than last year's Hondas ... this year's Fords have the same gas milage as last year's Fords ... therefore last year's Fords must have better gas milage than last year's Hondas?

The Insight gets better gas mileage than the Pilot ... The Escape gets the same gas mileage as the Taurus ... therefore the Taurus gets better gas mileage than the Insight?

Quite a leap in logic there.

The Toshiba 34HFX84 contains a "MegaBand Wideband Video Amplifier" which "improves video amplification by 50% allowing significant increases in video resolution to accurately reproduce HD video signals". The Toshiba 34HF84 doesn't. Which means exactly what when comparing the 34HF84 to some other set? I guess it means that the 34HF84 can't "accurately reproduce HD video signals" while other sets can? Of course not.

subysouth

11-16-04, 04:18 PM

Originally posted by montreal

"According to Sony, the number one selling point of its new product lineup is the high picture quality. The receiver unit is equipped with super fine pitch FD Trinitron. The center pitch of conventional receiver units used to be 0.77mm for 36-inch TV and 0.65mm for 32-inch TV. For the new products, however, the center pitch was made 0.47mm for 36-inch TV and 0.42mm for 32-inch TV, as a result of which the number of horizontal slits has increased by approximately 60%. The corner pitch has also been changed from 0.97mm to 0.61mm for 36-inch TV and from 0.90mm to 0.58mm for 32-inch TV. The image output circuit is compliant with 30MHz. On the audio side, the new products will realize Tru Surround function using six three-way speakers."

Those are the horizontal pitch numbers it needed to do as I said above to pull off 1400. My hats off to them, I will accept that they did and officially stand corrected. Its still well shy of 1920 but it is a commendably higher figure than other current sets. It is still only gonna be a benefit at close range.

The vertical resolution is still gonna be a source of debate.....

Be back later.

ss

dt_dc

11-16-04, 04:32 PM

Originally posted by montreal
Here's a excerpt from the Sony Press release that stated the pitch in millimeters.http://ne.nikkeibp.co.jp/english/2000/08/0828sony_dtv.htmlThen again ... from the same press release:Sony has announced its lineup of BS digital Hi-Vision TV:D :D :D

You'd think the translator could have come up with somthing a little better ...

montreal

11-16-04, 05:14 PM

[QUOTE]Originally posted by subysouth
The vertical resolution is still gonna be a source of debate..... /QUOTE]

I guess your question is - can all 1080 lines be displayed without each line being too far apart from its neighbor or too close?

Suppose you take that new Sony HD Cam that generates 1440 by 1080i and photograph a thin vertical red line down the center of a black rectangle posted on a wall.

Now feed that signal directly into the 34XBR960. The RED gun is going to turn on for a brief moment on every one of the 1080 scans that it takes to complete each frame. The question now is - will you see a column of 1080 red spots on the screen where each spot is barely touching its adjacent neighbor above and below itself?

The distance between the center of each spot to the center of the one below it will be about 0.4 mm (16.5 inches of vertical screen height divided by 1080 lines). But will the focus of the gun be sharp enough so that the diameter of the spot is also about 0.4 mm. in order to keep each spot from overlapping with its neighbor above?

I think yes because there would be no point in SONY creating an aperture grill with a pitch of 0.47 mm if your gun focus is considerably larger than this dimension.

So IMO, the XBR960 with its extra fine focusing beam allows all 1080 scan lines to be displayed without significant overlap. The use of phosphor bars that run continuously down the screen helps each vertical spot to have the same size and shape.

We now have 100% the vertical resolution and 73% of the horizontal resolution already achieved.

Right now, TV stations are transmitting 100% of the optimum vertical resolution and about 65% of the optimum horizontal resolution, so for the time being, Sony has a good match.

BigGreenMat

11-16-04, 06:05 PM

Alright well this thread has been awfully informative to me the noob as far as the actual physics and such involved in CRT technology. The question I have is why can't a CRT television produce greater resolutions? Haven't CRT PC Monitors been doing as great or great resoultions at >60hz for YEARS now? I mean you can easily get a 17" monitor that can display 1600x1200. According to what you all are stating here is the PC actually only showing at most 1100 lines by 625? This entire thread I constantly thought 'Why can't we have full 1080i resolution on such a large tube' and 'What is with all the problems with conversion'. CRT monitors have been doing these things for a while quite a bit better than any LCD technology. What am I missing here?

Oh and given all the things you have all stated is there any reason then that I should get say a Samsung CRT HDTV over a Samsung CRT EDTV? Is the question only one of what signals they receive or is the actual display different? Will an EDTV actually DISPLAY at 480p? Since HDTVs obviously don't display at 720p or 1080i.

gdg

11-16-04, 08:16 PM

I actually currently own both the Tosh 34hf83 and the Sony kd34xbr960. I mention this because I would like to think that I would assess both the sets on their merits and not based on the fact that I psychologically need to justify a purchase. One will have to go, and I don't really care which it is. The only difference is that if I keep the Sony it will have cost me a lot more money. On the other hand , and fortunately, if I sell it I probably won't loose a cent due to the fact I got a great deal and brought it into Canada where it's currently unavailable.
That said, I have to say that, from 8 feet back, on HD I find the Sony more subjectively involving. It seems more vibrant and dynamic that the Tosh. From that distance it's probably not the rez that's responsible so I'd just like to remind people that resolution is not the only thing Sony does well. I don't know how they do it, but there colors seem to "pop" more.
Also, looking at the Tosh screen, one can CLEARLY see that, while the front is flat, the back surface, upon which the picture is actually displayed, has quite a bit of curvature (particularly vertically). The flat front almost appears to have been designed to "fool" the eye into thinking the display is truly flat. The Sony, on the other hand, "appears" to be a lot closer to flat.
The 960 is a flagship TV from an industry leader and one can notice attention to detail in every aspect, not just in it's ability to resolve better than the competition. So once again, if one is concerned with PQ, I don't believe one can assess it's merits by focusing exclusively on it's "super fine pitch technology". (though that's where I started this thread)

Artwood

11-16-04, 08:22 PM

If Sony is able to achieve 1400 in 34-inch Widescreen and 36-inch 4:3, do you think they would have the technical expertise to boldly go where no one has gone before and dream the impossible dream and do the same 1400 in a larger size set? I'm sorry for being ridiciulous. Everyone knows that might decrease sales of 42-inch Rear Projection LCD. Making money is always more important than Picture Quality!

Geise

11-16-04, 08:25 PM

I personally would rather they spend their efforts on getting to a true 1080 resolution in ANY sized CRT :)

gdg

11-16-04, 09:05 PM

On one hand, and I've noticed it repeatedly, many people are critical of the fact that true HD is neither broadcast nor is current 34" CRT technology up to the task of reproducing it. More RESOLUTION dammit!!!!

On the other hand a number of the same people are claiming that, at realistic viewing distances, the eye can't even resolve the detail that is currently available. Sony is just playing a numbers game!!!!

Let's make up our mind. WHICH IS IT???
Do we want more resolution or not? Is a more resolving CRT a good thing or not? It seems to me it can't be both.:confused:

subysouth

11-16-04, 09:13 PM

Originally posted by montreal
[QUOTE]Originally posted by subysouth
The vertical resolution is still gonna be a source of debate..... /QUOTE]

I guess your question is - can all 1080 lines be displayed without each line being too far apart from its neighbor or too close?

Suppose you take that new Sony HD Cam that generates 1440 by 1080i and photograph a thin vertical red line down the center of a black rectangle posted on a wall.

Now feed that signal directly into the 34XBR960. The RED gun is going to turn on for a brief moment on every one of the 1080 scans that it takes to complete each frame. The question now is - will you see a column of 1080 red spots on the screen where each spot is barely touching its adjacent neighbor above and below itself?

The distance between the center of each spot to the center of the one below it will be about 0.4 mm (16.5 inches of vertical screen height divided by 1080 lines). But will the focus of the gun be sharp enough so that the diameter of the spot is also about 0.4 mm. in order to keep each spot from overlapping with its neighbor above?

I think yes because there would be no point in SONY creating an aperture grill with a pitch of 0.47 mm if your gun focus is considerably larger than this dimension.

So IMO, the XBR960 with its extra fine focusing beam allows all 1080 scan lines to be displayed without significant overlap. The use of phosphor bars that run continuously down the screen helps each vertical spot to have the same size and shape.

We now have 100% the vertical resolution and 73% of the horizontal resolution already achieved.

Right now, TV stations are transmitting 100% of the optimum vertical resolution and about 65% of the optimum horizontal resolution, so for the time being, Sony has a good match.

Whoa not so fast there. Theres only one big problem with that approach.

There isnt just one beam exiting that aperature grill, there are three. One for each red, blue and green phosphor. Unless Sony has been able to figure a way also to cycle the beam current 4200 times per line and use a single gun. The widescreen profile itself makes scaning an aperature pitch grille more challenging.

So now you have to figure a way that Sony can have a .45-61mm horizontal pitch and a .39mm average vertical stripe pitch(will be shorter in the center) and the horizontal has to comprise three distinct addressable phosphors arranged horizontally being addressed by three seperate guns with in theory three round beam spots. And no bleed or overlap.

Much taller order than 1400 lines horizontally. I dont share your assumption of 1080i without overlap. I think thats why you see a full picture at 1080i instead of scan lines as gdg noted. And it only has to muddy in one direction to muddy both directions.

ss

subysouth

11-16-04, 09:22 PM

Originally posted by gdg
On one hand, and I've noticed it repeatedly, many people are critical of the fact that true HD is neither broadcast nor is current 34" CRT technology up to the task of reproducing it. More RESOLUTION dammit!!!!

On the other hand a number of the same people are claiming that, at realistic viewing distances, the eye can't even resolve the detail that is currently available. Sony is just playing a numbers game!!!!

Let's make up our mind. WHICH IS IT???
Do we want more resolution or not? Is a more resolving CRT a good thing or not? It seems to me it can't be both.:confused:

I can say I dont want more resolution than about a .85mm pitch on a 34" screen. That equates to about 7' for viewing distance at full resolution . Again I would like to see better use of the resolution based on that pixel size.

Some people want it to look better closer, but there are tradeoffs to smaller pixels on CRTs.

ss

subysouth

11-16-04, 09:26 PM

Originally posted by Artwood
If Sony is able to achieve 1400 in 34-inch Widescreen and 36-inch 4:3, do you think they would have the technical expertise to boldly go where no one has gone before and dream the impossible dream and do the same 1400 in a larger size set? I'm sorry for being ridiciulous. Everyone knows that might decrease sales of 42-inch Rear Projection LCD. Making money is always more important than Picture Quality!

It you will research a bit on the way a CRT functions you will find that they are and have been running into real physical limitations to the CRT for years. Gun speed is a big problem. Yoke deflection is another. Drawing an image on a relatively flat large screen is filled with inherent hurdles. Not to mention the weight of such a finished product. 350lb 42" CRT anyone?

If you like CRT displays and want larger look to plasmas now as a compromise and SED in the future. SED solves all the CRTs inherent problems if they can figure a way to reliably create the arc.

ss

subysouth

11-16-04, 09:31 PM

Originally posted by BigGreenMat
Alright well this thread has been awfully informative to me the noob as far as the actual physics and such involved in CRT technology. The question I have is why can't a CRT television produce greater resolutions? Haven't CRT PC Monitors been doing as great or great resoultions at >60hz for YEARS now? I mean you can easily get a 17" monitor that can display 1600x1200. According to what you all are stating here is the PC actually only showing at most 1100 lines by 625? This entire thread I constantly thought 'Why can't we have full 1080i resolution on such a large tube' and 'What is with all the problems with conversion'. CRT monitors have been doing these things for a while quite a bit better than any LCD technology. What am I missing here?

Oh and given all the things you have all stated is there any reason then that I should get say a Samsung CRT HDTV over a Samsung CRT EDTV? Is the question only one of what signals they receive or is the actual display different? Will an EDTV actually DISPLAY at 480p? Since HDTVs obviously don't display at 720p or 1080i.

Yes an EDTV will easily pull off 480p. The wider a range in vertical resolution you ask the set to do, the worse will be its performance on one or more of them.

IMO 540p on one of these sets, particulary a dot shadow mask set, would look quite nice. The jury seems to still be out as to whether the Toshiba will do 540p on its latest sets on most input resolutions. If so that would deserve a hard look.

ss

gdg

11-16-04, 09:45 PM

SS
Why not just phone or email Toshiba? I'm 95% convinced 540p is not a universally applicable display option. Again, Sebceocanada (I think it was), talks specifically about DVD and non specific about HD sources. I would also point out that Toshiba is even worse than Sony in terms of overstating and exagerating it's feature's. I love there "proprietary" Colorstream technology. That's a "Good One"!!!;)

subysouth

11-16-04, 10:23 PM

Originally posted by gdg
SS
Why not just phone or email Toshiba? I'm 95% convinced 540p is not a universally applicable display option. Again, Sebceocanada (I think it was), talks specifically about DVD and non specific about HD sources. I would also point out that Toshiba is even worse than Sony in terms of overstating and exagerating it's feature's. I love there "proprietary" Colorstream technology. That's a "Good One"!!!;)

Yea they all love the words they can cobble together and then trademark. I will try to call them Thurs, I have a trip tomorrow during business hours.

I am personally leaning towards an ED plasma at this point largely because of my viewing distance. I am getting a set for the bedroom and my viewing distance is now a little over 10'.

ss

gdg

11-16-04, 10:54 PM

I guess those network logos don't worry you?:D

subysouth

11-16-04, 11:15 PM

Originally posted by gdg
I guess those network logos don't worry you?:D

It does worry me a little, but allegedly on these newer sets burn-in has been relegated to a temporary annoyance.

At least thats what theyre saying.....

They have extended the lifespan on the glass so that should coincide with a drop in burn-in potential....I hope.

Its gonna be a patch til better things come along I am also hoping. SED really has the potential of being the true CRT repalcement in larger sizes and lower weights and consistent screenwide performance.

ss

montreal

11-16-04, 11:20 PM

Originally posted by subysouth
Whoa not so fast there. Theres only one big problem with that approach.

There isn't just one beam exiting that aperture grill, there are three. One for each red, blue and green phosphor. Unless Sony has been able to figure a way also to cycle the beam current 4200 times per line and use a single gun. The widescreen profile itself makes scanning an aperture pitch grille more challenging.

There are three beams but they all move in tandem at the same time. When I talk about drawing a single vertical red line, only one gun will cycle on and off per scan line, 1080 times each frame. The Blue and Green guns remain silent. The only thing that changes with a widescreen profile is that the beam has to travel a longer distance to illuminate the edges of the screen and this means that the focus will be larger and the projection of the beam on the phosphors will be oval instead of round. That is why the pitch must be larger at the edges than in the center, but that just means that the wires that are strung vertically to form the grill are spaced a little more apart on the edges.

Originally posted by subysouth
So now you have to figure a way that Sony can have a .45-61mm horizontal pitch and a .39mm average vertical stripe pitch(will be shorter in the center) and the horizontal has to comprise three distinct addressable phosphors arranged horizontally being addressed by three separate guns with in theory three round beam spots. And no bleed or overlap.

Much taller order than 1400 lines horizontally. I don't share your assumption of 1080i without overlap. I think thats why you see a full picture at 1080i instead of scan lines as gdg noted. And it only has to muddy in one direction to muddy both directions.
ss

I agree that if it's going to muddy in one direction then its going to muddy in the other direction as well. And there is probably overlap because the beam diameter may actually be be fatter to allow the horizontal lines to all blend together when displaying 480p. Doing 1080i with this same beam means that the lines of alternate frames will definitely overlap the lines of the previous frames, but because of the decay of the phosphors, the eye tends to pick up 1080 lines of distinct visual information.

If I reword the question that the original poster asked:
Once you have optimized the diameter of a round shaped beam so that all 1080 horizontal lines can be scanned with minimum overlap, do you really need a horizontal pitch that is finer than the vertical thickness of the horizontal lines?

My answer would be no unless there is a way to create an electron beam which has a greater height than width. Does anyone know if the grid of the gun can allow the shape the beam to be "sculpted" ?

montreal

11-16-04, 11:34 PM

Originally posted by BigGreenMat
The question I have is why can't a CRT television produce greater resolutions? Haven't CRT PC Monitors been doing as great or great resolutions at >60hz for YEARS now? I mean you can easily get a 17" monitor that can display 1600x1200. What am I missing here?

The problem is that as resolution increases by making the holes in the mask smaller and closer together or by making an aperture grill with more vertical wires, the electron beams end up spending more time colliding with the mask and there are less electrons that hit the phosphors. The result is a screen that looks great from one foot away like a PC monitor but looks very dim when viewed from 6 feet back. That is why there is a balance struck between light output and detail, bearing in mind that when viewers are placed at a comfortable distance, there is a limit as to how much detail they can see.

subysouth

11-17-04, 12:29 AM

Originally posted by montreal
There are three beams but they all move in tandem at the same time. When I talk about drawing a single vertical red line, only one gun will cycle on and off per scan line, 1080 times each frame. The Blue and Green guns remain silent. The only thing that changes with a widescreen profile is that the beam has to travel a longer distance to illuminate the edges of the screen and this means that the focus will be larger and the projection of the beam on the phosphors will be oval instead of round. That is why the pitch must be larger at the edges than in the center, but that just means that the wires that are strung vertically to form the grill are spaced a little more apart on the edges.

I agree that if it's going to muddy in one direction then its going to muddy in the other direction as well. And there is probably overlap because the beam diameter may actually be be fatter to allow the horizontal lines to all blend together when displaying 480p. Doing 1080i with this same beam means that the lines of alternate frames will definitely overlap the lines of the previous frames, but because of the decay of the phosphors, the eye tends to pick up 1080 lines of distinct visual information.

If I reword the question that the original poster asked:
Once you have optimized the diameter of a round shaped beam so that all 1080 horizontal lines can be scanned with minimum overlap, do you really need a horizontal pitch that is finer than the vertical thickness of the horizontal lines?

My answer would be no unless there is a way to create an electron beam which has a greater height than width. Does anyone know if the grid of the gun can allow the shape the beam to be "sculpted" ?

They move together as a horizontally aligned trio of theoretically round beams. Like this OOO (which is basically what the Trinitron sets look like with associated sizable gaps between lines to maintain squareness.) It would need to look like this llll to squeeze that many pixels on the set and have 480p be viewable at all. Maybe sculpting the three beams like that is possible but any changes in power are going to amplify changes in vertical bleed.

You did hit on a key point I do agree with. The beam spot is likely oversized to reduce gaps on 480p, so the likelihood is you are already getting some overlap at a line count well short of 1080.

The more I have been pondering this the more I have realized a couple of things. Only on the Sony or another aperature grille equipped set would we even be having this discussion. The aperature due to its theoretically unlimited vertical reolution and horizontally aligned phosphors is uniquely equipped to have an argument's stab at HD and I see why Sony et al lobbied for softness on the horizontal HD resolution first. The comment that bothered me that you made in the other thread montreal was all the current HD monitors are supporting a 1080 vertical line count. Only the Sony and other aperature grille sets might do 1080. Theres no negotiating vertical resolution on a dot mask set, it either is or isnt and the ill effects of lower line counts on those sets would be amplified compared to an aperature grille set in some ways. Meaning they dont bleed anywhere near as much as the aperature grille types and 480p vs 1080i if they were doing it would be immediately and painfully obvious on the same set. I can think of some ways Sony or other aperature grille sets could work it back and forth to get average performance on both ends.

It has sparked a great discussion regardless and made me at least recall and outright learn how these sets actually work.

Im gonna still say that the max resolvable vertical is well below 1080. Where it is I dont know but logic would say Sony should err towards somewhere in the middle of 480 and 1080.

I still think for my viewing pleasure I would prefer a larger dot pitch(with more point control of light output) screen driven progressively to its native resolution. I dont want to be stuck in no mans land on a set trying to do two widely different line counts. And again I question whether the size pixels on this set in particular are useful for the average person and worry about what was done to maintain light output against that smaller pitch/beam spot.

ss

dt_dc

11-17-04, 01:34 AM

Originally posted by subysouth
I dont share your assumption of 1080i without overlap. I think thats why you see a full picture at 1080i instead of scan lines as gdg noted. And it only has to muddy in one direction to muddy both directions.Easy enough to test for overlapping scan lines ...

To gdg and anyone else with a Sony Direct View:

As always, properly calibrate using Video Essentials or Avia. Once you have an otherwise well-calibrated set ...

1) Pull up some HD content. A relatively bright, uniform scene will make this easier.
2) Turn Picture setting (aka contrast, aka white level) all the way down.
3) Look very very closely ... you should see very slight gap between scan lines. Hard to see, but they should be there.
4) Now that you know what you're looking for ... slowly start turning Picture back up
5) Stop exactly at the point when the scan lines dissapear
6) Picture setting should be very close to where it started ... whites should appear white ... and the set should be reasonably bright

- If you can't see scan lines in #3, set is most likely out of focus.
- Any Direct View set that achieves #6 has shown some fairly impressive characteristics.

For kicks I did the above on my 34XBR800 ... no overlapping scan lines.

dt_dc

11-17-04, 01:54 AM

Originally posted by montreal
And there is probably overlap because the beam diameter may actually be be fatter to allow the horizontal lines to all blend together when displaying 480p.Except that scan lines DON'T blend at 480p or 960i. There's a noticable gap between scan lines when not running at 1080i.

Well, noticeable at 2 ft. ... not noticable at 6 ft.

gdg

11-17-04, 03:00 AM

Originally posted by subysouth
....and worry about what was done to maintain light output against that smaller pitch/beam spot.

ss

Well, Sony has decided to back up the 960 with a full 2 year warranty. They must have, at least some, faith in the durability of their new technology. I believe that Toshiba's full warranty is only for 1 year.

montreal

11-17-04, 10:34 AM

Originally posted by subysouth
The comment that bothered me that you made in the other thread montreal was all the current HD monitors are supporting a 1080 vertical line count.

What I meant by that is that all these monitors will cause the guns to sweep across the screen 1080 times every thirtieth of a second. Whether you see 1080 distinct lines vertically without too much overlap will depend on how sharp the focus is.

If it is true, as some claim, that the beam focus is sharp enough so that the resulting horizontal lines do indeed have a thickness of about 0.4 mm. (thin enough so that there is actually a slight gap visible between horizontal lines when viewed up close at 480p), then that means that the beam might also allow an average aperture grill pitch of about 0.55 mm. to deliver optimum results.

Again, why would Sony have gone to the trouble to place the phosphor stripes so closely together without improving the sharpness of the electron beams at the same time? When the XBR910 was introduced, I remember reading in the Sony catalog that their MICROFOCUS guns had been included. Formerly, MICROFOCUS guns had only been used on large CRT RPTVs.

In the case of a shadow mask versus an aperture grill and the ability of each to reduce bleeding, one would have to know the physical dimensions of the openings in the metal screening relative to the space between the openings in order to draw any conclusions.

gdg

11-17-04, 02:03 PM

Any opinion on whether there is any real advantage in the "megaband" wide band video amplifier, used in the Tosh 34hfx83/84, over the "regular" wideband video amplifier, used in the 34hf83/84?
Or is this, as some have suggested, just a marketing gimmick with no realistically practical advantage.

montreal

11-17-04, 03:12 PM

Originally posted by gdg
Any opinion on whether there is any real advantage in the "megaband" wide band video amplifier, used in the Tosh 34hfx83/84, over the "regular" wideband video amplifier, used in the 34hf83/84?
Or is this, as some have suggested, just a marketing gimmick with no realistically practical advantage.

Having an amplifier that passes higher frequencies is always better even when you don't have a fine pitch mask/grill that can take advantage of this.

The reason is that the amplifier can switch the guns on and off faster (slew rate) provided the input signal has a high frequency content. Switching a gun on faster means that the phosphor elements become fully activated more quickly at the position of transition where we are going from full black to full light. Even if our focus is large and muddy, the transitions are still crisper.

For Sony models, the wider band amplifier is commercially called the HD Detailer and was introduced with the XBR800 to pass up to 30 mhz which is way above what my aperture grill of 850 slots can display.

PaulGo

11-17-04, 03:53 PM

Originally posted by gdg
Any opinion on whether there is any real advantage in the "megaband" wide band video amplifier, used in the Tosh 34hfx83/84, over the "regular" wideband video amplifier, used in the 34hf83/84?
Or is this, as some have suggested, just a marketing gimmick with no realistically practical advantage.

Unless Toshiba discloses the specification of these "wideband" video amplifiers (was 2003 different from 2004?) who knows. The best test is taking these sets and using test patterns determine if their is a difference in resolution. However at normal viewing distances I doubt you could tell the difference. From what I have read at Keohi HDTV their was a major improvement between 2002 and 2003. In 2002 the video amplifier could not produce a satisfactory resolution on even DVDs. According to them Toshiba redesigned the circuitry for 2003 and it now produces all the resolution a DVD is capable of (and I assume it greatly helped HDTV resolution also).

subysouth

11-18-04, 12:13 AM

Originally posted by montreal
What I meant by that is that all these monitors will cause the guns to sweep across the screen 1080 times every thirtieth of a second. Whether you see 1080 distinct lines vertically without too much overlap will depend on how sharp the focus is.

If it is true, as some claim, that the beam focus is sharp enough so that the resulting horizontal lines do indeed have a thickness of about 0.4 mm. (thin enough so that there is actually a slight gap visible between horizontal lines when viewed up close at 480p), then that means that the beam might also allow an average aperture grill pitch of about 0.55 mm. to deliver optimum results.

Again, why would Sony have gone to the trouble to place the phosphor stripes so closely together without improving the sharpness of the electron beams at the same time? When the XBR910 was introduced, I remember reading in the Sony catalog that their MICROFOCUS guns had been included. Formerly, MICROFOCUS guns had only been used on large CRT RPTVs.

In the case of a shadow mask versus an aperture grill and the ability of each to reduce bleeding, one would have to know the physical dimensions of the openings in the metal screening relative to the space between the openings in order to draw any conclusions.

When 1080 lines are laid over the back of a aperature grille screen it is debatable whether all of the lines are discretely displayed. When 1080 lines are a laid across the back of a dot mask screen with 611(an example found in the 1st gen Panny 34") vertical dots, there is no longer a debate. The maximum vertical resolution possible is 611, it may be less but never more.

The aperature grille is a compromise in brightness vs bleed. There is NO vertical delineation of phosphor triad stripes and minimal horizontal. Vertical bleed in a set of this nature is IMO a guarantee. Its almost unavoidable.

On the other hand is much more easy to eliminate bleed entirely on a dot mask set because so much material is dedicated to the mask. The downside is lower brightness given the same general screen size. Dimmer but sharper. You are correct that exact opening vs mask dimensions would firm it up, but especially in the vertical some mask is much more likely to reduce bleed than no mask at all correct?

ss

subysouth

11-18-04, 12:19 AM

Originally posted by gdg
Any opinion on whether there is any real advantage in the "megaband" wide band video amplifier, used in the Tosh 34hfx83/84, over the "regular" wideband video amplifier, used in the 34hf83/84?
Or is this, as some have suggested, just a marketing gimmick with no realistically practical advantage.

As others have said, if it works it would be better, but theres little gorunds for actual comparison. Have to just take their word. It wouldnt be a pro or con for me.

The nastiest test pattern to test bandwidth is a square wave single pixel alternate black/white vertical stripe pattern. If it can do this well at the target scan rate it can do anything you need.

I dont think bandwidth is really an issue on these sets. It has already been demonstrated bandwidths can be higher than these sets need to function properly.

ss

subysouth

11-18-04, 12:32 AM

Originally posted by dt_dc
Easy enough to test for overlapping scan lines ...

To gdg and anyone else with a Sony Direct View:

As always, properly calibrate using Video Essentials or Avia. Once you have an otherwise well-calibrated set ...

1) Pull up some HD content. A relatively bright, uniform scene will make this easier.
2) Turn Picture setting (aka contrast, aka white level) all the way down.
3) Look very very closely ... you should see very slight gap between scan lines. Hard to see, but they should be there.
4) Now that you know what you're looking for ... slowly start turning Picture back up
5) Stop exactly at the point when the scan lines dissapear
6) Picture setting should be very close to where it started ... whites should appear white ... and the set should be reasonably bright

- If you can't see scan lines in #3, set is most likely out of focus.
- Any Direct View set that achieves #6 has shown some fairly impressive characteristics.

For kicks I did the above on my 34XBR800 ... no overlapping scan lines.

dt, I want you to think about another possible outcome to this test.

Picture the aperature grille in question and lets just for arguments sake say that the line count is some what deficient.

Picture the Sony laying say a .6mm tall beamspot size on .4mm line centers. What is the resultant image on an apearture grille screen? The areas of overlap are actually brighter than the native scan lines themselves. In a relative sense the native lines appear like "scan lines" or a darkened area between lines. I have seen this effect on CRT front projectors and based on the continuous vertical phospors on the Sony, I cant see why such and effect couldnt occur.

You can see this efect in overlapping the two circles generated by two falshlights. The overlapped area will be brighter than the un-overlapped areas.

You would need to examine the screen closely to be sure or be able to progressively increase vertical line count so that the appraoch to overlap is more readily visible. You can do this on a computer monitor. My 19" computer monitor for instance is supposed to support 1600x1200 but the magic full screen without line overlap at reasonable brightness is about 1280x1024. At 1600x1200 you do get this weird bright and brighter scan lines.

ss

subysouth

11-18-04, 12:34 AM

Isnt Joe kane working on an HD DVE? A 1000 line vertical test pattern would be just the ticket.

ss

gdg

11-18-04, 02:16 AM

Strangely, the 960 doesn't appear to be capable of converting to 480p or 540p itself. I can see lines in 480i broadcasts on all picture display modes ie progressive, DRC or interlaced. On the other hand it seems to do fine if fed a progressive signal. The picture displayed from my Panansonic RP82 is pristine, with no lines visible. That Ok with me because I would never get the TV to do the progressive conversion when I have a DVD player with a state of the art (or close to it) Farouja de-interlacer.

Dearth

11-18-04, 08:28 AM

Originally posted by subysouth
Isnt Joe kane working on an HD DVE? A 1000 line vertical test pattern would be just the ticket.

ss

.... it has been out for a long while, again here is a clip from the Gary Merson review of the 34xbr910 in which he uses the HD DVE to test the resolution and concludes it lines up with 1400 lines. I guess you can lead a horse to water but you can't make him drink.

"I moved on to HDTV signals. I have on hand Joe Kane’s new HD Digital Video Essentials (DVE) on D-VHS D-Theater tape. There are two versions, 720p and 1080i. This set upconverts 720p input signals to 1080i so I choose the 1080i version of the tape for my tests. DVE contains an extensive array of test patterns and some original HD content. I concentrated on its multi-burst patterns, which are used to examine HD display resolution capabilities. The top pattern I could resolve was the 22MHz pattern, which by no coincidence matches up to the set’s super-fine picture tube’s 1400+ horizontal resolution."

And again another link to the full article if you want to actually read it this time ;)

http://www.theperfectvision.com/newsletter/tpv51/sony_kv34xbr910.html

montreal

11-18-04, 10:23 AM

Originally posted by subysouth
When 1080 lines are laid over the back of a aperture grille screen it is debatable whether all of the lines are discretely displayed. When 1080 lines are a laid across the back of a dot mask screen with 611(an example found in the 1st gen Panny 34") vertical dots, there is no longer a debate. The maximum vertical resolution possible is 611, it may be less but never more.

The aperture grille is a compromise in brightness vs bleed. There is NO vertical delineation of phosphor triad stripes and minimal horizontal. Vertical bleed in a set of this nature is IMO a guarantee. Its almost unavoidable.

On the other hand is much more easy to eliminate bleed entirely on a dot mask set because so much material is dedicated to the mask. The downside is lower brightness given the same general screen size. Dimmer but sharper. You are correct that exact opening vs mask dimensions would firm it up, but especially in the vertical some mask is much more likely to reduce bleed than no mask at all correct?

ss

I agree with you 100%, that masking, whether vertical or horizontal, reduces bleeding in those respective directions.

I am less concerned about vertical bleeding compared to horizontal bleeding because it has been shown that the human eye/visual perception process is much more sensitive to horizontal resolution than vertical resolution. Try turning your head sideways for a while reading this text and see how the demarcation between horizontal lines of text (graphics) becomes sharper.

I also agree with you that if the Panny has 611 holes vertically, then it is going to behave like a fixed pixel display with 611 vertical elements. The difference being that for the fixed display, there is a computer trying to intelligently remap 1080 lines to about 700 and in the case of the Panny, the remapping is done mechanically by the shadow mask in a hit or miss fashion.

montreal

11-18-04, 10:39 AM

Originally posted by subysouth
The nastiest test pattern to test bandwidth is a square wave single pixel alternate black/white vertical stripe pattern.

Does anyone know the maximum pixel format of the photos stored on a Sony Memory Stick taken by a digital Sony camera?

I think the XBR960 tries to remap this high density format into its own internal format, but I don't know what internal format it chooses, 480p or 960i, or 1080i.

Would creating a custom JPEG test pattern with Adobe Photoshop and then displaying it on the XBR960 using the stick reader give us a better idea of how sharp the beam really is?

subysouth

11-18-04, 11:32 AM

Originally posted by Dearth
.... it has been out for a long while, again here is a clip from the Gary Merson review of the 34xbr910 in which he uses the HD DVE to test the resolution and concludes it lines up with 1400 lines. I guess you can lead a horse to water but you can't make him drink.

"I moved on to HDTV signals. I have on hand Joe Kane’s new HD Digital Video Essentials (DVE) on D-VHS D-Theater tape. There are two versions, 720p and 1080i. This set upconverts 720p input signals to 1080i so I choose the 1080i version of the tape for my tests. DVE contains an extensive array of test patterns and some original HD content. I concentrated on its multi-burst patterns, which are used to examine HD display resolution capabilities. The top pattern I could resolve was the 22MHz pattern, which by no coincidence matches up to the set’s super-fine picture tube’s 1400+ horizontal resolution."

And again another link to the full article if you want to actually read it this time ;)

The resolution in question at this juncture is the vertical not the horizontal.

ss

subysouth

11-18-04, 11:55 AM

Originally posted by montreal
I agree with you 100%, that masking, whether vertical or horizontal, reduces bleeding in those respective directions.

I am less concerned about vertical bleeding compared to horizontal bleeding because it has been shown that the human eye/visual perception process is much more sensitive to horizontal resolution than vertical resolution. Try turning your head sideways for a while reading this text and see how the demarcation between horizontal lines of text (graphics) becomes sharper.

I also agree with you that if the Panny has 611 holes vertically, then it is going to behave like a fixed pixel display with 611 vertical elements. The difference being that for the fixed display, there is a computer trying to intelligently remap 1080 lines to about 700 and in the case of the Panny, the remapping is done mechanically by the shadow mask in a hit or miss fashion.

I do agree that the human is somewhat more sensitve in the horizontal by design, however vertical bleed can contribute to an overall softened picture especially if there is more than just bleed, outright overlap.

Is the Panny set not knowingly repainting a large percentage of those next 540 field lines on the same exact phosphors it just painted in the preceding field? It cant light the phosphor triads correctly if it doesnt know their location and count. The Panny set knows its not doing a legitimate 1080i because it doesnt have the seperate pixels to lay the info on, same as the Sony sets know they arent painting more than 850 or 1400 of the theoretical 1920 in the horizontal. These sets know exactly how many horizontal triads they have and in the case of the Panasonic, exactly the vertical too. The Sony gun could be shooting for a given location in the vertical and not an exact triad group because the phosphor is borderless in the vertical. I am however dramatically more comfortable believing the resolution numbers on the Sony H and Panny H&V(albeit much lower.) That Sony V is still loaded with potential issues IMO.

I think all CRTs should function like a fixed pixel device. Any thing above or below the sweet spot of resolution the set is not doing well. Sets should not be being asked to do both 480p and 1080i if a quality picture is desired. There are huge compromises when this is done. For instance, that Panny IMO should always be driven at 611p with all sources. CRTs are really no more or less variable resolution devices than any other display, in that varying the resolution has compromises. Same as it would on a plasma. You could force a 768p plasma to display 480p. The plasma manufacturers have not allowed you at this juncture to shoot yourself in the foot that way, and yet CRT manufacturers are doing it for you. If I believed these sets were truly capable of 1080i or 720p or whatever actual resolution, I would say scale everything to that. I still believe widely disparate sets are bieng asked to do unrealistic things to satisfy "HD" display. If the best picture is really the goal, IMO there is a better way, native rates for all.

ss

subysouth

11-18-04, 12:06 PM

Originally posted by montreal
Does anyone know the maximum pixel format of the photos stored on a Sony Memory Stick taken by a digital Sony camera?

I think the XBR960 tries to remap this high density format into its own internal format, but I don't know what internal format it chooses, 480p or 960i, or 1080i.

Would creating a custom JPEG test pattern with Adobe Photoshop and then displaying it on the XBR960 using the stick reader give us a better idea of how sharp the beam really is?

I for one am satisified(and was as soon as I saw montreal's numbers on horizontal pitch) that the Sony can do the 1400 H res and I think bandwidth isnt gonna be a problem either. Other "lesser" 34" sets have exceeded this bandwidth already by a pretty healthy margin.

I would concentrate on resolving the 1080 vertical line performance question. It would seem likely its gonna lock into a lower line count progressive display for still pictures. It would be interesting to see what it did with a 1080 vertical alternating black/white line picture though.

ss

dt_dc

11-18-04, 12:49 PM

Originally posted by subysouth
dt, I want you to think about another possible outcome to this test.
1) With Picture turned all the way down, you can see a (very small) distinct, sharp, black gap between scan lines. In your scenerio above, overlapping scan lines would not provide small black line /(sharp transition)/ white line (OK, actually with Picture/Contrast turned down it's small black line / grey line) ... they would provide white line /(fuzzy transition)/ whiter line. Black line / white line is what I'm seeing ... which to me indicates an actual gap.
2) Joe Kane, Guy Kuo, Gary Merson, and others have talked about sets with the inability to properly seperate scan lines for ... well, for longer than I have been in to home theater. It is so easy to test for ... the end results are so obvious. Unfortunately, I don't have a DVHS deck and Digital Video Essentials (or an HD signal generator). However, anyone who 1) does and 2) is at all competent would be able to test this extremely quickly (and would do so while reviewing the set).
3) If, as your suggested, the results at the end of my test above were that scan lines were actually overlapping by 50% ... the reulting picture would be so poor ...

That being said ... yes ... alot of people probably are running their set with overlapping scan lines ...One caveat: Do not bump the Contrast/Picture parameter too high. If you do, the resolution will not realize its full potential. With HDTV sources, we ended up with a setting of about 30 percent, which produced approximately 18 footlamberts. That brightness is fine for viewing the TV in dim rooms with the lights off. For DVD and other sources, we were able to switch to around 40 percent and get a significantly brighter picture.
http://hardware.gamespot.com/Story-ST-1341-x-10-11-x

The old light-output vs. resolution issue for CRTs ... which is a valid issue for people looking at this set (will your viewing environment allow for the resolution you're paying $$$ for).

Now, unfortunately I don't have a test to ensure the set is actually scanning at 1080i. The old 'resolvable resolution' vs. 'actual resolution' ... and how CRTs are constructed ... prevents me from knowing how to actually test for that. Perhaps there is a way, but I don't know of it.

However, since
1) Sony explicitly states that it does
2) It's part of the CEA's labeling requirements for HDTV ... over manufacturers would likely take issue if it didn't
3) I have seen no credible information to suggest otherwise

I'm going to go with 1080i ... not overlapping.

subysouth

11-18-04, 01:19 PM

Originally posted by dt_dc
1) With Picture turned all the way down, you can see a (very small) distinct, sharp, black gap between scan lines. In your scenerio above, overlapping scan lines would not provide small black line /(sharp transition)/ white line (OK, actually with Picture/Contrast turned down it's small black line / grey line) ... they would provide white line /(fuzzy transition)/ whiter line. Black line / white line is what I'm seeing ... which to me indicates an actual gap.
2) Joe Kane, Guy Kuo, Gary Merson, and others have talked about sets with the inability to properly seperate scan lines for ... well, for longer than I have been in to home theater. It is so easy to test for ... the end results are so obvious. Unfortunately, I don't have a DVHS deck and Digital Video Essentials (or an HD signal generator). However, anyone who 1) does and 2) is at all competent would be able to test this extremely quickly (and would do so while reviewing the set).
3) If, as your suggested, the results at the end of my test above were that scan lines were actually overlapping by 50% ... the reulting picture would be so poor ...

That being said ... yes ... alot of people probably are running their set with overlapping scan lines ...
http://hardware.gamespot.com/Story-ST-1341-x-10-11-x

The old light-output vs. resolution issue for CRTs ... which is a valid issue for people looking at this set (will your viewing environment allow for the resolution you're paying $$$ for).

Now, unfortunately I don't have a test to ensure the set is actually scanning at 1080i. The old 'resolvable resolution' vs. 'actual resolution' ... and how CRTs are constructed ... prevents me from knowing how to actually test for that. Perhaps there is a way, but I don't know of it.

However, since
1) Sony explicitly states that it does
2) It's part of the CEA's labeling requirements for HDTV ... over manufacturers would likely take issue if it didn't
3) I have seen no credible information to suggest otherwise

I'm going to go with 1080i ... not overlapping.

Maybe - maybe not. Without out an appropriate test pattern or a known line deficient count on the set(particularly with you dropping contrast) I am not sure what you are seeing isnt what I described.

On your quoted paragraph, increasing contrast effectively increases beam spot size along with brightness. You might interpret the above to say, that too high a contrast creates line overlap and that a relatively low contrast is required to control it.

Also on the issue of manufacturers calling each other on actual resolution or the feds calling them on it.

Like I cited earlier Gary Merson and WSR KNEW and published that the $6500 1st gen set by Panasonic being sold as a 1080i set had only 611 vertical hole count in its dot mask. Even if you ignored the horizontal, which was still defined at that point at 1920, for 1080i, the 1080 still had to be satisfied, but it clearly wasnt on the Panny by a large margin. Theres no discussion on what its full vertical res potential was. Its maximum is 1117x611 and yet no feds stopped Panasonic from selling the set and Sony et al didnt call them on it. Wanna know why I think that is? People in glass houses dont throw stones. Even if by some miracle the latest Sony 34" "HD" sets are producing 1400x1080i(still not full 1080i,) what about all the earlier non-Super Fine pitch sets Sony et al have already sold as HD? You think they want to open that can of worms? You get consumers begining to question what 1080i is and the consensus is gonna turn out at 1920x1080i, and other consumers will agree. Can you see the probs?

We can because of the design of Sony's set have an interesting discussion about what its vertical res potential is. Other dot mask sets dont have that luxury. And just because we can discuss it on the Sony, doesnt mean its doing the 1080 vertical lines IMO - the jury is still way out on that point. Like I said earlier my hat is off for Sony dialing in 1400 in the horizontal(although youre gonna need to sit close to appreciate) but by comparison thats a cakewalk compared to doing the V 1080 without overlap on an aperature grille set. There should be a vertical test pattern on HD DVE.

ss

montreal

11-18-04, 01:42 PM

Originally posted by subysouth
Is the Panny set not knowingly repainting a large percentage of those next 540 field lines on the same exact phosphors it just painted in the preceding field? It cant light the phosphor triads correctly if it doesn't know their location and count.

Most modern TVs use digital timers and precision DACs to make sure that as the vertical amplifier places each new horizontal line below the previous one, the line positioning on the alternate frame is exactly a half line height lower than the line positioning of the previous frame. This slight offset is all the difference that there is between 540p and 1080i (or 480p and 960i). In spite of this, the guns blindly paint the lines not knowing how well the beams are going to line up with the shadow mask holes.

It is impossible to record the X Y coordinate position of each of the half million holes in the mask into the computer memory so that the beam position can be dynamically corrected on the fly for each hole location.

Assuming you could achieve such a perfect alignment in the factory, by the time the TV gets transported to the owner and gets subject to all the thermal, magnetic, and mechanical stresses that take place over time, the original performance would be so badly corrupted that no advantage would have been gained by this exercise.

So the general approach is to just shoot all the electron bullets in a fixed mechanical way and hope that the net result looks reasonable. Anyone who has ever done a static convergence of the three guns on a color TV knows what I mean when I say that CRTs are a compromise taken to reconcile many competing forces. We accept these geometric compromises because in return we get an image with a greater contrast ratio and perhaps better color purity than with fixed pixel displays.

Originally posted by subysouth
[B]The Panny set knows its not doing a legitimate 1080i because it doesn't have the separate pixels to lay the info on, same as the Sony sets know they aren't painting more than 850 or 1400 of the theoretical 1920 in the horizontal.B]

The world is not made up of visual textures boxed at 1920 units per panorama width. The world is an analog place. We chop the image up into an arbitrarily chosen format of 1920 units for transmission purposes but quickly try to melt the 1920 units back into one continuous streak as faithfully as audio CDs try to recreate music by blending 44 thousand samples together each second. The goal in audio is not to synchronize the sampling rate with the frequency of the guitar string. It to make analog momentarily digital and then analog again.

Therefore the Sony and Panny need not care if the analog scan line painted by each gun takes into account the number of horizontal holes in the shadow mask and the number of pieces of data in a transmission signal. The guns have already forgotten that the signal arrived as 1920 discrete units of data per line. To do its job properly the gun doesn't want to know this fact. Each gun just wants to spray a continuously varying stream of electrons squarely onto the solid block of monotone phosphor that it sees laying behind the holes in the mask. Each gun sees a block of a different primary color. (The Sony may have one gun, but this single gun has three different barrels spaced side by side.)

It is the precision mechanical positioning of the mask in the factory that determines if there is a straight line of site between each red phosphor spot on the inside of the screen and the end of the barrel of the red gun located some 20 inches back. Same for the other two colors. Because it is hard to get this perfect for all half million red phosphor spots, purity magnets have to be added afterward to coax the beam to bend slightly to prevent corruption on the edges of the screen. Once this is done, you are stuck with what might be slight bowing of vertical and horizontal lines that may appear at different locations on the screen. To correct these, the computer can slightly adjust the deflection amplifiers dynamically, but these corrections are generalized over large areas and not particular locations on the screen where bowing is occurring.

xrox

11-18-04, 02:52 PM

Originally posted by montreal
It is impossible to record the X Y coordinate position of each of the half million holes in the mask into the computer memory so that the beam position can be dynamically corrected on the fly for each hole location.

So the general approach is to just shoot all the electron bullets in a fixed mechanical way and hope that the net result looks reasonable. Anyone who has ever done a static convergence of the three guns on a color TV knows what I mean when I say that CRTs are a compromise taken to reconcile many competing forces. We accept these geometric compromises because in return we get an image with a greater contrast ratio and perhaps better color purity than with fixed pixel displays.
I absolutely agree. The gun does not directly target a single specific phosphor dot. It has absolutely no positional information of the phosphor dots.

Also, correct me if I'm wrong, but doesn't color selection occur in CRTs solely due to the angle of the gun and nothing to do with targeting only a specific color dot.

http://www.uniklinikum-giessen.de/kis-ris-pacs/archiv/2001/mi1240.pdf

Although montreal, what you speak of has been done in the F!T tube. There is a photodetector for each triad which sends feedback (actual information of position, brightness) to the gun that then adjusts to compensate for any errors.

dt_dc

11-18-04, 03:16 PM

Originally posted by subysouth
Also on the issue of manufacturers calling each other on actual resolution or the feds calling them on it.The HDTV labeling requirements for CRT are explicitly based on SCAN RATE. Not resolution of the actual mask ... or resolvable details ... or anything of the sort.

They are based on SCAN RATE.

Once again ... SCAN RATE.

Let's say it again ... SCAN RATE.

Yes, this was intentionally done because everyone (manufacturers, FCC, anyone who took the time to examine) knew they COULD make a CRT scan at 1080i while they couldn't actually fully resolve the detail.

Lots of people pointed this out when the labeling requirements came out.

That's why the labeling requirements are based on SCAN RATE.

That's (merely one of) the reasons I listed why I felt sure that when Sony says it's SCAN RATE is 1080i ... it's SCAN RATE is 1080i.

As noted several times here ... manufacturers don't (usually) make (explicit) resolution claims.

But they do explicitly state their SCAN RATE ... and if they were off, someone would likely call them on it.

SCAN RATE (sorry, had to do it one more time).

subysouth

11-18-04, 03:57 PM

Originally posted by montreal
Most modern TVs use digital timers and precision DACs to make sure that as the vertical amplifier places each new horizontal line below the previous one, the line positioning on the alternate frame is exactly a half line height lower than the line positioning of the previous frame. This slight offset is all the difference that there is between 540p and 1080i (or 480p and 960i). In spite of this, the guns blindly paint the lines not knowing how well the beams are going to line up with the shadow mask holes.

It is impossible to record the X Y coordinate position of each of the half million holes in the mask into the computer memory so that the beam position can be dynamically corrected on the fly for each hole location.

Assuming you could achieve such a perfect alignment in the factory, by the time the TV gets transported to the owner and gets subject to all the thermal, magnetic, and mechanical stresses that take place over time, the original performance would be so badly corrupted that no advantage would have been gained by this exercise.

So the general approach is to just shoot all the electron bullets in a fixed mechanical way and hope that the net result looks reasonable. Anyone who has ever done a static convergence of the three guns on a color TV knows what I mean when I say that CRTs are a compromise taken to reconcile many competing forces. We accept these geometric compromises because in return we get an image with a greater contrast ratio and perhaps better color purity than with fixed pixel displays.

The world is not made up of visual textures boxed at 1920 units per panorama width. The world is an analog place. We chop the image up into an arbitrarily chosen format of 1920 units for transmission purposes but quickly try to melt the 1920 units back into one continuous streak as faithfully as audio CDs try to recreate music by blending 44 thousand samples together each second. The goal in audio is not to synchronize the sampling rate with the frequency of the guitar string. It to make analog momentarily digital and then analog again.

Therefore the Sony and Panny need not care if the analog scan line painted by each gun takes into account the number of horizontal holes in the shadow mask and the number of pieces of data in a transmission signal. The guns have already forgotten that the signal arrived as 1920 discrete units of data per line. To do its job properly the gun doesn't want to know this fact. Each gun just wants to spray a continuously varying stream of electrons squarely onto the solid block of monotone phosphor that it sees laying behind the holes in the mask. Each gun sees a block of a different primary color. (The Sony may have one gun, but this single gun has three different barrels spaced side by side.)

It is the precision mechanical positioning of the mask in the factory that determines if there is a straight line of site between each red phosphor spot on the inside of the screen and the end of the barrel of the red gun located some 20 inches back. Same for the other two colors. Because it is hard to get this perfect for all half million red phosphor spots, purity magnets have to be added afterward to coax the beam to bend slightly to prevent corruption on the edges of the screen. Once this is done, you are stuck with what might be slight bowing of vertical and horizontal lines that may appear at different locations on the screen. To correct these, the computer can slightly adjust the deflection amplifiers dynamically, but these corrections are generalized over large areas and not particular locations on the screen where bowing is occurring.

So your position is any number of discrete horizontal triads can display HD as long as the product looks good? I'm afraid I can even remotely agree with that if thats your position. If it doesnt have a seperate triad to support that bit of pixel info, its not discrete. If you want 1920 of horizontal you need 1920 triads and they need to be addressed discretely. It cant be any other way IMO, regardless of how subjectively good the finished product is.

Following your logic why not just take a 640x480 set and throw 1920x1080 at a 16:9 window therein and call it HD? Why even try to raise actual resolution of any set? Sony spent all that money on research for their news Super Fine pitch screens cause they like people? Or they are trying to take a better stab at producing something they know they havent been producing?

If the three discrete guns of set cant locate the particular target phosphors at a very high rate of success how does the picture generally turn out correct? I have no doubt that all pixels are not addressed correctly on each set, but by and large they are. They generally pull this off by making the spot of the beams somewhat larger than their target to increase chances of lighting them correctly.

ss

subysouth

11-18-04, 04:03 PM

Originally posted by dt_dc
The HDTV labeling requirements for CRT are explicitly based on SCAN RATE. Not resolution of the actual mask ... or resolvable details ... or anything of the sort.

They are based on SCAN RATE.

Once again ... SCAN RATE.

Let's say it again ... SCAN RATE.

Yes, this was intentionally done because everyone (manufacturers, FCC, anyone who took the time to examine) knew they COULD make a CRT scan at 1080i while they couldn't actually fully resolve the detail.

Lots of people pointed this out when the labeling requirements came out.

That's why the labeling requirements are based on SCAN RATE.

That's (merely one of) the reasons I listed why I felt sure that when Sony says it's SCAN RATE is 1080i ... it's SCAN RATE is 1080i.

As noted several times here ... manufacturers don't (usually) make (explicit) resolution claims.

But they do explicitly state their SCAN RATE ... and if they were off, someone would likely call them on it.

SCAN RATE (sorry, had to do it one more time).

So again as above. You believe when a consumer buys an HD set they are buying scan lines placed over an arbitrary number of actually resolvable pixels?

Actually producing a 1920x1080i res picture is a luxury eh? Somehow I dont think everyone thinks that. I am fairly certain most buyers of HD sets believe they are buying a producable resolution, not a scan rate which represetns only a small part od producing an HD picture. I can hear them bragging about the scan rates and caring little about the actual picture. You are welcome to believe what you like though.

Hey I'm fine with your overall assessment because I dont beleive theyre actually producing the resolution anyway. I might not be so forgiving if I had actually purchased on of these "HD" sets.

ss

montreal

11-18-04, 04:10 PM

Originally posted by xrox
Also, correct me if I'm wrong, but doesn't color selection occur in CRTs solely due to the angle of the gun and nothing to do with targeting only a specific color dot.

Colors are originally detected in the studio camera and split up into three different blocks of data (signals) corresponding to primary colors so that when three images prepared with the blocks of data are superimposed on one another, they blend together to create a faithful reproduction.

Along the way, the information, whether in analog or digital form, may be encoded to pass as one single stream, but eventually, each CRT gun receives only the information belonging to a single primary color as it existed in the studio camera. So the colors are not really "selected", they are more or less kept separate from start to finish until they reach the guns. And the beams generated by the guns are kept separate until they arrive at phosphor spots by using physical obstacles (holes) to mechanically guide the beams.

The red gun simply emits a stream of electrons whose volume varies in proportion to the intensity of the red input signal. This beam wants to travel straight forward and hit a spot in the center of the screen. It is the job of the deflection plates and coils to bend this beam (in fact all 3 beams in parallel) so the beam(s) gets evenly sprayed over the complete backside surface of the shadow mask.

Someone in the factory has preprinted a pattern of phosphors on the inside of the screen and has punched a grid of holes in a sheet of thin metal foil at precise distances apart and has suspended this foil at a precise distance back from the phosphor coating.

The result is that as the beams pass through the holes, the beams are no longer bending at this point, and merely continue in straight lines and strike only phosphor dots belonging to the same primary color family.

XROX, when we look at the diagrams of your attachment showing the arrangement of guns, mask and phosphors, we are given the false impression that the holes are much smaller than the amount of metal between the holes.

In fact the opposite is true. In this diagram, if we could place the guns,mask and phosphors at positions that are proportional to the actual positions in a real CRT, we would see that as the beams get constantly bent during scanning, they nevertheless pass through all the holes in a way that the final part of each trajectory brings each beam in contact only with all the dots of one color.

subysouth

11-18-04, 04:14 PM

For you guys who think the guns dont know where the phosphor dots are, how do you think the set works? The phosphors are not horizontally continuous. As a matter of fact on dot mask sets the triad configuration flips each triad, if the gun didnt know where the discrete phosphors were, you couldnt correctly display a solid blue field for instance.

The gun knows where the triads and subsequent phosphor dots are or the set wouldnt work.

Here are some close up pics of several fields on a dot mask set, note how specific phosphors at exact relative levels are lit on each field:

http://www.infocellar.com/hardware/monitor/shadowmask-colors3.jpg

If the set didnt know where the specific dots are it couldnt do this. And theyre again flipping each triad. You guys are underestimating the CRTs skills and alignment with the screen.

ss

xrox

11-18-04, 04:23 PM

montreal,

So are you saying that the signal determines color selection. Yes but what I meant was how does the CRT guns selectively excite colors. Maybe I used the wrong term.

Actually no, all the crt papers i read in sid always state color seclection is done by the mask. There is one opening in the mask for threee colors (see link)

What I mean is if one red dot is excited by the red gun (the only dot on the screen) and you move this one dot picture across the screen there is no way in hell it can excite any other color other than red because that is the angle it makes with the mask. Yes the three beams come together at a point through the mask hole but the angles are maintained afterwords.

Look at the link in my previous post: under "color selection"

Also
http://an.hitchcock.org/repairfaq/REPAIR/F_crtfaq.html#CRTFAQ_006

Maybe I'm just misinterpreting it.

Geise

11-18-04, 04:38 PM

Your diagram illustrates what Montreal just posted about masks and beams and phosphors and such (from what I can tell :)). One thing I don't understand is if CRT's are as "fixed" as you and montreal just mentioned, how the heck can they scale different resolutions so well and accurately?

subysouth

11-18-04, 04:59 PM

Originally posted by xrox
montreal,

So are you saying that the signal determines color selection. Yes but what I meant was how does the CRT guns selectively excite colors. Maybe I used the wrong term.

Actually no, all the crt papers i read in sid always state color seclection is done by the mask. There is one opening in the mask for threee colors (see link)

What I mean is if one red dot is excited by the red gun (the only dot on the screen) and you move this one dot picture across the screen there is no way in hell it can excite any other color other than red because that is the angle it makes with the mask. Yes the three beams come together at a point through the mask hole but the angles are maintained afterwords.

Look at the link in my previous post: under "color selection"

Also
http://an.hitchcock.org/repairfaq/REPAIR/F_crtfaq.html#CRTFAQ_006

Maybe I'm just misinterpreting it.

The colors of the phosphor dots are set at production, red dots dont do blue. The beams can be flipped though. Meaning the back end is where the flipping and intensity variance comes from. All the beams do is say which phosphor is lit and how bright, but to work correctly it has to be pointing exactly at the correct color phosphor dot. It is anything but arbitrary.

And again just to show how competent it is view those test patterns. Those beams are rotating(flipping vertically) each horizontal triad and turning off and back on on each triad too. The CRT addresses each phosphor individually.

Bow down before the skills oh non-believers.:p

ss

subysouth

11-18-04, 05:03 PM

montreal

11-18-04, 05:05 PM

Originally posted by subysouth
So your position is any number of discrete horizontal triads can display HD as long as the product looks good? I'm afraid I can't even remotely agree with that if that's your position. If it doesn't have a separate triad to support that bit of pixel info, its not discrete. If you want 1920 of horizontal you need 1920 triads and they need to be addressed discretely. It cant be any other way IMO, regardless of how subjectively good the finished product is.

At six feet back I can't see 1920 pixels across a 34" screen so I'm not going to press Sony to improve the aperture pitch. If I was watching a 60" projection TV screen from 6 feet back then I might want to have 1920 slots (triads) across. A CRT is not supposed to be discrete. It's just supposed to give as crisp an image as possible. We aren't doing AUTOCAD drawings here. If you're doing graphics (games) you need a fixed pixel device to take full advantage of the available detail.

Originally posted by subysouth
Following your logic why not just take a 640x480 set and throw 1920x1080 at a 16:9 window therein and call it HD? Why even try to raise actual resolution of any set? Sony spent all that money on research for their news Super Fine pitch screens cause they like people? Or they are trying to take a better stab at producing something they know they haven't been producing?

You're right, if HD is by definition the realization of the full potential from the 1920 by 1080 individual bytes of information that is available, then only a fixed pixel screen of 1920 by 1080 elements will fit the bill and perhaps it is wrong to advertise that one's product is HD if it really doesn't respect this definition.

[QUOTE]Originally posted by subysouth
[B]If the three discrete guns of the TV set can't locate the particular target phosphors at a very high rate of success how does the picture generally turn out correct? I have no doubt that all pixels are not addressed correctly on each set, but by and large they are. They generally pull this off by making the spot of the beams somewhat larger than their target to increase chances of lighting them correctly.ss

The guns indeed have a great rate of success locating the targets of like colors even though they are firing off in a blind manner. The success has to do with the fact that you can punch holes in a metal foil at precise distances and position the foil properly and make the holes of a proper diameter so that the blind but fairly repetitive trajectories of the electrons always pass through the holes at the proper angles. There is no need to bloom up the focal point of the beam to achieve some sort of overkill.

In fact each of the 600 odd vertical holes of that Panny may be of a large enough diameter and the focus of the beam may be sharp enough that two horizontal lines that are adjacent to each other (on successive frames) may appear separate due to the fact at a beam passes through the same hole but at a slightly different angle due to a minute change in the deflection amplifier as the frames unroll. Here we have one hole, one triad, but we may in fact see the alternate illumination the upper and lower part if the same phosphor spot.

There were plenty of monochromatic displays used in CADCAM that had a continuous sheet of phosphor coating and at the same time they had remarkably sharp focusing that allowed extremely thin lines to be drawn. Why can't the same phenomena be happening within the confines of a single color dot?

subysouth

11-18-04, 05:14 PM

Originally posted by montreal
At six feet back I can't see 1920 pixels across a 34" screen so I'm not going to press Sony to improve the aperture pitch. If I was watching a 60" projection TV screen from 6 feet back then I might want to have 1920 slots (triads) across. A CRT is not supposed to be discrete. It's just supposed to give as crisp an image as possible. We aren't doing AUTOCAD drawings here. If you're doing graphics (games) you need a fixed pixel device to take full advantage of the available detail.

The guns indeed have a great rate of success locating the targets of like colors even though they are firing off in a blind manner. The success has to do with the fact that you can punch holes in a metal foil at precise distances and position the foil properly and make the holes of a proper diameter so that the blind but fairly repetitive trajectories of the electrons always pass through the holes at the proper angles. There is no need to bloom up the focal point of the beam to achieve some sort of overkill.

In fact each of the 600 odd vertical holes of that Panny may be of a large enough diameter and the focus of the beam may be sharp enough that two horizontal lines that are adjacent to each other (on successive frames) may appear separate due to the fact at a beam passes through the same hole but at a slightly different angle due to a minute change in the deflection amplifier as the frames unroll. Here we have one hole, one triad, but we may in fact see the alternate illumination the upper and lower part if the same phosphor spot.

There were plenty of monochromatic displays used in CADCAM that had a continuous sheet of phosphor coating and at the same time they had remarkably sharp focusing that allowed extremely thin lines to be drawn. Why can't the same phenomena be happening within the confines of a single color dot?

Youre kind avoiding the question.

Would you be fine with someone selling you a sub resolution device as an HD? I know all about subjective resolution at x distance and the pointlessness generally of HD on small sets. Those are seperate points. I am not selling sets as HD - they are.

Your second bit is a set manufacturers argument "it could light seperate phosphor dots in seperate pixels." However what hapens if you need red and you only have blue and green at your disposal in that portion of the triad(very likely btw)? Doesnt work does it?

The only reasonable assessment of any direct-view CRT maximum resolution is its amount of discrete triads. Anything else is rationalizing IMO.

The guns are not even remotely firing off blindly. Each of the 3 electron guns is precisely aimed at individual phosphor dots addressing a single triad at a time. There is absolutely nothing blind about it.

ss

xrox

11-18-04, 05:21 PM

Originally posted by subysouth
Masks dont do anything but help assist the guns hit only the phosphor dots theyre aiming at. That is all. ss

But that is what I said whas it not?

Take this example: If there was not a mask and absolute perfect focus and geometry, then what happens when you adjust the picture position (move it vertically or horizontally). Without a mask the red beam would now mover over the green or blue to get to another red dot. The mask in place prevents this because the ONE hole in the mask per triad has a SPECIFIC angle that is only met by the RED beam.

unless of course the link is wrong :)

Tell me the following:

1 - Is there an opening in the mask per dot? or per triad? If it is per triad then how can there not be an angle dependance?

2 - What do they mean in the SID journals when they say that CRT masks are needed for color selection?

If possible I don't just want an interpretation (as admittedly this is mine) but rather some proof (link or something)

Thanks
Cheers

montreal

11-18-04, 05:40 PM

Originally posted by Geise
Your diagram illustrates what Montreal just posted about masks and beams and phosphors and such (from what I can tell :)). One thing I don't understand is if CRT's are as "fixed" as you and montreal just mentioned, how the heck can they scale different resolutions so well and accurately?

The screens are fixed and optimized for one vertical resolution - 540p (and 1080i which is two frames of 540p where the second frame is slightly offset from the first). The vertical dot pitch will be chosen to more or less match the 540 different trajectories from the gun to the screen where these trajectories must pass through a column of 600 odd holes. It is in fact the computer which does such a good job of mapping 525i, 480p, and 720p to 540 horizontal lines. Because Sony has continuous vertical phosphor stripes, it can support 480 horizontal lines per frame as easily as it can support 540 scan lines per frame because the beam doesn't have to pass through a hole.

Remember that these masks have to be compatible around the world where the number of scan lines varies slightly from one continent to another. It appears that Panny's 611 verticals holes are the best fit for 540 lines in one country and 625 lines in another country.

xrox

11-18-04, 05:43 PM

Originally posted by montreal
The guns indeed have a great rate of success locating the targets of like colors even though they are firing off in a blind manner. The success has to do with the fact that you can punch holes in a metal foil at precise distances and position the foil properly and make the holes of a proper diameter so that the blind but fairly repetitive trajectories of the electrons always pass through the holes at the proper angles. There is no need to bloom up the focal point of the beam to achieve some sort of overkill.

I'm with you on this one :)

Question about scan lines: Would I be wrong to think that 1080 is resolvable due to the fact that when "vertical squeeze" is turned on there is a noticeable attenuation of the spaces between scan lines? Not to mention an improvement in picture.

subysouth

11-18-04, 05:44 PM

Originally posted by xrox
But that is what I said whas it not?

Take this example: If there was not a mask and absolute perfect focus and geometry, then what happens when you adjust the picture position (move it vertically or horizontally). Without a mask the red beam would now mover over the green or blue to get to another red dot. The mask in place prevents this because the ONE hole in the mask per triad has a SPECIFIC angle that is only met by the RED beam.

unless of course the link is wrong :)

Tell me the following:

1 - Is there an opening in the mask per dot? or per triad? If it is per triad then how can there not be an angle dependance?

2 - What do they mean in the SID journals when they say that CRT masks are needed for color selection?

If possible I don't just want an interpretation (as admittedly this is mine) but rather some proof (link or something)

Thanks
Cheers

When you move the picture horizontally or vertically the set readjusts for the know triads now under its gun. It has a rather accurate map of where the triads are, all youre doing is choosing which ones you want to use by moving the picture(raster) on the screen. You cant trick the set. It knows when youre moving/resizing the image, its a step ahead of you always.

1. One opening per triad that all three beams enter and exit at different angles. The mask stops bleed to adjacent pixels - that is all. It mildy adjusts the beams by fanning them a bit but its not a requirement. The aperature grille for instance is almost like having no mask at all.

2. I have no idea what they are saying.

Pic:
http://www.infocellar.com/hardware/monitor/shadowmask-beams.gif

ss

xrox

11-18-04, 05:52 PM

Originally posted by subysouth

1. One opening per triad that all three beams enter and exit at different angles. The mask stops bleed to adjacent pixels - that is all. It mildy adjusts the beams by fanning them a bit but its not a requirement. The aperature grille for instance is almost like having no mask at all.

2. I have no idea what they are saying.

Pic:
http://www.infocellar.com/hardware/monitor/shadowmask-beams.gif

ss

thanks subs,

so there is an angle dependence, even with an arpeture grill (see my link)

I took my scope up to my computer screen and watched as I moved the picture both vertically and horizontally and I was right. When a red beam moves over a blue or green dot (which it does) there is no excitation because the angle is incorrect!! But when it reaches the next red dot it lights it up.

subysouth

11-18-04, 05:54 PM

Originally posted by montreal
The screens are fixed and optimized for one vertical resolution - 540p (and 1080i which is two frames of 540p where the second frame is slightly offset from the first). The vertical dot pitch will be chosen to more or less match the 540 different trajectories from the gun to the screen where these trajectories must pass through a column of 600 odd holes. It is in fact the computer which does such a good job of mapping 525i, 480p, and 720p to 540 horizontal lines. Because Sony has continuous vertical phosphor stripes, it can support 480 horizontal lines per frame as easily as it can support 540 scan lines per frame because the beam doesn't have to pass through a hole.

Remember that these masks have to be compatible around the world where the number of scan lines varies slightly from one continent to another. It appears that Panny's 611 verticals holes are the best fit for 540 lines in one country and 625 lines in another country.

Dont mean to contradict but this is absolutely incorrect. The guns themselves are at a fixed point in space, the screen is fixed. Only the seperation of the guns(distance also fixed) themselves allows one point on the gun to hit three on the screen.

Start thinking now about what you just said. You are saying the computer is changing the laws of physics?

Those beams leaving those guns passing through a fixed hole are always gonna hit one and only one triad.

You get 540 out of 611 by turning off 71 lines of triads or scaling 540p to 611p which we have no evidence its doing.

ss

montreal

11-18-04, 05:55 PM

Originally posted by xrox

Tell me the following:

1 - Is there an opening in the mask per dot? or per triad? If it is per triad then how can there not be an angle dependence?

2 - What do they mean in the SID journals when they say that CRT masks are needed for color selection?

If possible I don't just want an interpretation (as admittedly this is mine) but rather some proof (link or something)

Thanks
Cheers

WE are using different words but we appear to have exactly the same understanding of the situation. There is one hole per triad (triangle formed by three different colored dots) and the guns are arranged in an upside down triangle. At any point in time, all three beams can be passing simultaneously through the same hole en-route to three different spots in the same triad. It is the ratio of intensity between the three beams during that instant that determines how strongly each of the three individually colored phosphor dots in the triad turns on. It is the eye ,at a reasonable distance, that mixes the three minute sources of light into one color. So in a manner of speaking, color is uniquely determined by signal strength of each of the three input signals and not by any magical targeting of a myriad of colored spots by some intelligent gun(s).

subysouth

11-18-04, 05:59 PM

Originally posted by montreal
WE are using different words but we appear to have exactly the same understanding of the situation. There is one hole per triad (triangle formed by three different colored dots) and the guns are arranged in an upside down triangle. At any point in time, all three beams can be passing simultaneously through the same hole en-route to three different spots in the same triad. It is the ratio of intensity between the three beams during that instant that determines how strongly each of the three individually colored phosphor dots in the triad turns on. It is the eye ,at a reasonable distance, that mixes the three minute sources of light into one color. So in a manner of speaking, color is uniquely determined by signal strength of each of the three input signals and not by any magical targeting of a myriad of colored spots by some intelligent gun(s).

You are contradicting yourself. You say its happening but its arbitrary. There is nothing arbitrary about. The guns know exactly what triad theyre pointing at at all times and vary their signals to generate the correct color and intensity on the three dots. And then it turns itself off shifts guns and moves to the next triad and repeats. Each sucessive triad has a different alignment - triangle, upside down triangle, triangle, etc.

Youre right its not magic, its physics and skills. And its a lot more complicated and precise than you apparently understand.

ss

montreal

11-18-04, 06:00 PM

Originally posted by xrox
I'm with you on this one :)

Question about scan lines: Would I be wrong to think that 1080 is resolvable due to the fact that when "vertical squeeze" is turned on there is a noticeable attenuation of the spaces between scan lines? Not to mention an improvement in picture.

Your right. When anamorphic DVDs are vertically squeezed, the lines begin to overlap and there is less vertical detail. But compared to the alternative where the 480p lines are letter-boxed and many scan lines are wasted on the black bars leaving fewer viewable lines to display the image, it is better to have the image using 480 lines that overlap then say 350 lines which don't.

xrox

11-18-04, 06:03 PM

Originally posted by montreal
WE are using different words but we appear to have exactly the same understanding of the situation. There is one hole per triad (triangle formed by three different colored dots) and the guns are arranged in an upside down triangle. At any point in time, all three beams can be passing simultaneously through the same hole en-route to three different spots in the same triad. It is the ratio of intensity between the three beams during that instant that determines how strongly each of the three individually colored phosphor dots in the triad turns on. It is the eye ,at a reasonable distance, that mixes the three minute sources of light into one color. So in a manner of speaking, color is uniquely determined by signal strength of each of the three input signals and not by any magical targeting of a myriad of colored spots by some intelligent gun(s).

Ahh I see, you were thinking about color reproduction (greyscale). I was trying to describe how the mask selectively excited single colors by using an angle dependance (ie - there is no way you can make the red gun excite a blue phosphor)

Cheers :)

BTW, if you don't recall, you and dt_dc taught me pretty much everything I know about CRTs a long while back!

Thanks again

subysouth

11-18-04, 06:12 PM

Originally posted by xrox
thanks subs,

so there is an angle dependence, even with an arpeture grill (see my link)

I took my scope up to my computer screen and watched as I moved the picture both vertically and horizontally and I was right. When a red beam moves over a blue or green dot (which it does) there is no excitation because the angle is incorrect!! But when it reaches the next red dot it lights it up.

Its not the angle. See the phosphor triad flip bit - trianlge, upside down triangle bit.

You moving the picture has nothing to do with moving the triads on the screen or the gun. The screen is being refreshed likely 60/sec. Its telling the gun to light up the next available red as you relocate the image. Its way ahead of you. Youre arent moving the image, youre telling it to move the image or manipulate it, its doing that with its known set of triads.

Its fly by wire not direct geometry movement. If you could move the geometry like that the screen would be constantly misaligned.

ss

montreal

11-18-04, 06:20 PM

Originally posted by subysouth
You are contradicting yourself. You say its happening but its arbitrary. There is nothing arbitrary about. The guns knows exactly what triad they're pointing at at all times and varies their signals to generate the correct color and intensity on the three dots.

You're right its not magic, its physics and skills.

ss

It is arbitrary in the sense that the guns have no idea where the holes are but since there is very little metal between the holes, no matter where a beam lands on the mask, many of the electrons are going to pass through a hole at any point in time. Arbitrary also due to the fact that the scan line positioning may not be a perfect match to the vertical dot pitch. Arbitrary does not mean random or reckless. There is indeed a near perfect electro-mechanical clockwork to it all, that repeats in such a predictable manner that success is assured.

You appear to understand what is physically happening, but to suggest that the guns have some sort of knowledge, or that the computer knows where all the holes and triads are located, is incorrect. SD CRT color TVs worked very well long before computers were added to them. HD CRT color TVs work better simply because the parts are smaller. The computer can translate incoming formats to the native resolution, but its still the same dumb CRT color TV. Like a car with the same old cylinders but the carburetor has been replaced by injectors. Sorry I have to go. See you all tomorrow.

PS. this is not fly by wire. Fly by wire is where you replace a mechanical linkage with an electronic communications circuit and then feed back the attempted movement to the steering wheel to create a sensation that there is a mechanical linkage. The gun receives no such confirmation as to how the trajectory of its beam is doing. It simply hopes for the best.

dt_dc

11-18-04, 06:20 PM

Originally posted by subysouth
So again as above. You believe when a consumer buys an HD set they are buying scan lines placed over an arbitrary number of actually resolvable pixels?

Actually producing a 1920x1080i res picture is a luxury eh?No, that's not what I said at all.

You seemed to say two things:

1) The Sony sets can't possibly be actually scanning at 1080i

2) If they were ... the scan lines must be overlapping

I was just showing 1 and 2 (when the set is properly calibrated) to be false.

With an aperture grill that gives you ...

subysouth

11-18-04, 06:23 PM

Originally posted by dt_dc
No, that's not what I said at all.

You seemed to say two things:

1) The Sony sets can't possibly be actually scanning at 1080i

2) If they were ... the scan lines must be overlapping

I was just showing 1 and 2 (when the set is properly calibrated) to be false.

With an aperture grill that gives you ...

How did you show these were false again? I must have missed that. You have definitive proof the Sony is doing 1080 V?

ss

subysouth

11-18-04, 06:31 PM

Originally posted by montreal
It is arbitrary in the sense that the guns have no idea where the holes are but since there is very little metal between the holes, no matter where a beam lands on the mask, many of the electrons are going to pass through a hole at any point in time. Arbitrary also due to the fact that the scan line positioning may not be a perfect match to the vertical dot pitch. Arbitrary does not mean random or reckless. There is indeed a near perfect electro-mechanical clockwork to it all, that repeats in such a predictable manner that success is assured.

You appear to understand what is physically happening, but to suggest that the guns have some sort of knowledge, or that the computer knows where all the holes and triads are located, is incorrect. SD CRT color TVs worked very well long before computers were added to them. HD CRT color TVs work better simply because the parts are smaller. The computer can change translate incoming formats to the native resolution, but its still the same dumb CRT color TV. Like a car with the same old cylinders but the carburetor has been replaced by injectors. Sorry I have to go. See you all tomorrow.

Thats just not true. The set knows exactly where its pointing, its the only way it works. Again it has to put the red beam specifically on the red phosphor, light it accordingly, shut off, realigns for the next riad and lights it, etc. The only way you can generate the precise images you see on CRTs is with a precise relationship between set and screen.

Or you could believe in magic.

There is nothing digital or analog about pointing a gun at a set of phosphors or the set knowing what phosphors its hitting. The set addresses each triad specifically based upon a map of those triads. If you dont believe it take a look at the test patterns again. There is nothing arbitrary about the sets behavior, it is demonstrating exact per triad control.

ss

Edit: And montreal there is no implicit of feedback in fly-by-wire, it could or could not have any feedback at all. The case I meant was when you locate a raster on a CRT, you arent mechanically re-locatiing the image, youre doing it electronically. And in the case of CRTs its way ahead on your behavior. Your are manipulating the image and its electronically producing the results against its capabilities set. You cant make a set light the wrong phosphors by manipulating the image on the screen. It wont let you.

dt_dc

11-18-04, 06:38 PM

One caveat: Do not bump the Contrast/Picture parameter too high. If you do, the resolution will not realize its full potential. With HDTV sources, we ended up with a setting of about 30 percent, which produced approximately 18 footlamberts. That brightness is fine for viewing the TV in dim rooms with the lights off. For DVD and other sources, we were able to switch to around 40 percent and get a significantly brighter picture.
http://hardware.gamespot.com/Story-ST-1341-x-10-11-x
Originally posted by subysouth
On your quoted paragraph, increasing contrast effectively increases beam spot size along with brightness. You might interpret the above to say, that too high a contrast creates line overlap and that a relatively low contrast is required to control it.You could read it that way because that's exactly what it says. Quite honestly it's a much more important point than "is there 1400 or 1100 slots".

It's more appropriate on a calibration thread, but this has become a catch-all so ...

Perfectly calibrated, the set produces 18 footlamberts. That's bright enough for my basement theater (no windows) with the overhead lights dimmed (not off, but dimmed). It's NOT bright enough for my living room (windows) durring the day. Honestly, it's not even bright enough for my basement with all the lights (a few halogens in there) on.

If I put the set in my living room, or turn on all the lights in my basement, I've got a choice:
1) Turn up contrast and start loosing detail
2) Keep contrast low ... but the picture is too dark to enjoy

This is a CLASSIC compromise with CRT.

However, if I keep the set in my basement ... and the lights dimmed ... I can enjoy a bright enough image at maximum detail.

If I turn all the lights on (like my wife likes to do) ... well, I've got a compromised setting for that.

If I move the set up to the living room ... I'd have a compromised setting for that too.

There are some CRTs (used to be LOTS of CRTs) that can't even produce enough light output in my dark, windowless basement when contrast is properly set.

The different settings for DVD vs. HD is a good point ... I hadn't thought about that and it's an important reminder for calibrating each source.

subysouth

11-18-04, 06:44 PM

Originally posted by dt_dc
http://hardware.gamespot.com/Story-ST-1341-x-10-11-x
You could read it that way because that's exactly what it says. Quite honestly it's a much more important point than "is there 1400 or 1100 slots".

It's more appropriate on a calibration thread, but this has become a catch-all so ...

Perfectly calibrated, the set produces 18 footlamberts. That's bright enough for my basement theater (no windows) with the overhead lights dimmed (not off, but dimmed). It's NOT bright enough for my living room (windows) durring the day. Honestly, it's not even bright enough for my basement with all the lights (a few halogens in there) on.

If I put the set in my living room, or turn on all the lights in my basement, I've got a choice:
1) Turn up contrast and start loosing detail
2) Keep contrast low ... but the picture is too dark to enjoy

This is a CLASSIC compromise with CRT.

However, if I keep the set in my basement ... and the lights dimmed ... I can enjoy a bright enough image at maximum detail.

If I turn all the lights on (like my wife likes to do) ... well, I've got a compromised setting for that.

If I move the set up to the living room ... I'd have a compromised setting for that too.

There are some CRTs (used to be LOTS of CRTs) that can't even produce enough light output in my dark, windowless basement when contrast is properly set.

The different settings for DVD vs. HD is a good point ... I hadn't thought about that and it's an important reminder for calibrating each source.

None of that constitutes proof. Its all opinions. There are other things that could explain those results, like I mentioned before.

Proof would be an HD vertical test pattern such as I imagine is on HD DVE, but I dont have a copy.

ss

montreal

11-18-04, 06:48 PM

Originally posted by subysouth
Thats just not true. The set knows exactly where its pointing, its the only way it works. Again it has to put the red beam specifically on the red phosphor, light it accordingly, shut off, realigns for the next triad and lights it, etc. The only way you can generate the precise images you see on CRTs is with a precise relationship between set and screen.

Or you could believe in magic.

There is nothing digital or analog about pointing a gun at a set of phosphors or the set knowing what phosphors its hitting. The set addresses each triad specifically based upon a map of those triads. If you don't believe it take a look at the test patterns again. There is nothing arbitrary about the sets behavior, it is demonstrating exact per triad control.

ss

Last post.
No matter where the red beam lands due to it being bent by the deflection circuits, it has no choice but to land on a red spot. That is completely due to the geometric relationship between the position of the spot, the hole, and the gun as well as the size of the hole. There is no need to position, fire, realign, fire again, and so on. The beam never shuts off, it flows continuously, the deflection flows continuously. That is what analog is all about.

For the most part, we have the same understanding of the path the bullets take. We even agree that the bullet hits its target due to the "precise relationship between set and screen". You seem to imply that the deflection circuits must be intelligently controlled and the guns need to be switched on and off like pulsed lasers in order for this all to be happening.

I'm just saying that this would all be happening in the same way by simply using a simple ramp generator to feed the deflection circuits like in the good old days. Bye

xrox

11-18-04, 06:51 PM

Originally posted by subysouth
Its not the angle. See the phosphor triad flip bit - trianlge, upside down triangle bit.

You moving the picture has nothing to do with moving the triads on the screen or the gun. The screen is being refreshed likely 60/sec. Its telling the gun to light up the next available red as you relocate the image. Its way ahead of you. Youre arent moving the image, youre telling it to move the image or manipulate it, its doing that with its known set of triads.

Its fly by wire not direct geometry movement. If you could move the geometry like that the screen would be constantly misaligned.

ss

That's not what I saw!

A fully red dot looks like the setting sun when I move the picture, and the top and bottom adjacent red dots becom partially illuminated. then as I continue to move the picture the next red dot looks like the risinig sun. It is selective excitation.

The picture show that for three beams to enter a single hole (per triad) they must be focused to a point then each seperate beam continues on seperately at different ANGLES to the mask.

Question : if the red dot is always to the left of the mask hole how can it be excited by the red gun if the three beems meet at a point in the mask (draw it out and you'll see it)

No more ryhmes I mean it!!!!!!!!!

Anybody want a peanut?

Anyway here's my interpretation: If there are angles between the beams and they are subsequently focused into a point then the angles are maintained beyond that point (NO MATTER WHERE THAT POINT IS!!!!). The shadow mask combined with this effect makes it impossible to excite a red dot with the blue gun!!!!

dt_dc

11-18-04, 06:56 PM

Originally posted by subysouth
Proof would be an HD vertical test pattern such as I imagine is on HD DVE, but I dont have a copy.Actually it wouldn't be proof ... but we're going to have to reach that point slowly.

Sorry for getting in to white level / contrast. That blurb was not 'proof' of anything. It's just something that's very important for (anyone) who wants to understand how a CRT works ... and anyone who's purchasing (or looking in to) a high-end CRT.

subysouth

11-18-04, 07:02 PM

Originally posted by montreal
Last post.
No matter where the red beam lands due to it being bent by the deflection circuits, it has no choice but to land on a red spot. That is completely due to the geometric relationship between the position of the spot, the hole, and the gun as well as the size of the hole. There is no need to position, fire, realign, fire again, and so on. The beam never shuts off, it flows continuously, the deflection flows continuously. That is what analog is all about.

For the most part, we have the same understanding of the path the bullets take. We even agree that the bullet hits its target due to the "precise relationship between set and screen". You seem to imply that the deflection circuits must be intelligently controlled and the guns need to be switched on and off like pulsed lasers in order for this all to be happening.

I'm just saying that this would all be happening in the same way by simply using a simple ramp generator to feed the deflection circuits like in the good old days. Bye

Hmmm, I thought there was a problem somewhere. Most of what you just said is just incorrect. The gun may not cycle off and on but it could, it has that ability. It addresses each triad as a speciifc event in that linear progression. Remember I mentioned the brutal cycle(square wave) of off one triad on the next or alternating vertical black and white stripes one triad wide? Thats as bad as it gets for a crts processing ability.

Lemme show you a pic of a phosphor stripe:
http://www.infocellar.com/hardware/monitor/crt-line1.gif

Note the position of just say the red phosphor as you move down the stripe. The phosphor dots relocate each triad and yet the guns relocate to light them. If the set didnt know the location of each individual phosphor the set couldnt do this. Nothing arbitrary or lucky about it. The set knows the location of each triad and phosphor dot. What or how you want the image displayed on them is up to you, but it controls the phosphors behavior intimately.

The deflection control of the electron beams IMO exceeds intelligent, its nigh on genius by design. Because that control is analog in no way diminishes the effectiveness of the act itself.

ss

xrox

11-18-04, 07:05 PM

xrox

11-18-04, 07:08 PM

If the three beams come together to a spot and then continue on after in a straight line there is a fundamental angle dependence (LAWS OF MATH). Since that spot corresponds with the mask hole there is only ONE PLACE that RED beam is goin.........

to a RED DOT!

subysouth

11-18-04, 07:14 PM

Originally posted by xrox
That's not what I saw!

A fully red dot looks like the setting sun when I move the picture, and the top and bottom adjacent red dots becom partially illuminated. then as I continue to move the picture the next red dot looks like the risinig sun. It is selective excitation.

The picture show that for three beams to enter a single hole (per triad) they must be focused to a point then each seperate beam continues on seperately at different ANGLES to the mask.

Question : if the red dot is always to the left of the mask hole how can it be excited by the red gun if the three beems meet at a point in the mask (draw it out and you'll see it)

No more ryhmes I mean it!!!!!!!!!

Anybody want a peanut?

Anyway here's my interpretation: If there are angles between the beams and they are subsequently focused into a point then the angles are maintained beyond that point (NO MATTER WHERE THAT POINT IS!!!!). The shadow mask combined with this effect makes it impossible to excite a red dot with the blue gun!!!!

I see the problem. There is some key event we're missing here. Clearly the guns are able to relocate the phosphors each sucessive triad but how can it light portions of two lines with the same beam in the same pass.

The beam shouldnt be in two places at once. But for the relocation of the phosphors in the stripe I could see the angle thing.

Unfortunately I havent seen a test pattern that shows a scan line seperation with more than one set of triad colors in two vertial stripes lit simultaneously.

Something is missing and I'm tapped out.

ss

subysouth

11-18-04, 07:17 PM

Originally posted by xrox
%^%%$ isn't that what I just said and was told was wrong. ANGLES PEOPLE :)

Thats an aperature grille. Thats also correct, but it doesnt apply as near as I can tell to the dot mask strip.

ss

xrox

11-18-04, 07:18 PM

And you know what else, since the angles are three dimensional (triangle) the angle dependaence is also 3D (vertical and horizontal)

What does that mean, well..........IMO

The gun can paint a scan line any #$#$@$@# place it wants to as long as the three beams are focused to an absolute point (which it is not)

Any misalignment and color purity will be lost!

subysouth

11-18-04, 07:51 PM

Originally posted by xrox
And you know what else, since the angles are three dimensional (triangle) the angle dependaence is also 3D (vertical and horizontal)

What does that mean, well..........IMO

The gun can paint a scan line any #$#$@$@# place it wants to as long as the three beams are focused to an absolute point (which it is not)

Any misalignment and color purity will be lost!

This angle thing may be it but honestly my brain hurts and I cant put it together.

Lets look at it again tomorrow.

ss

montreal

11-18-04, 07:58 PM

While my supper's heating up in the microwave, i'd like to stop for a moment and heap some praise on subysouth and xrox for bringing forth excellent pictorial evidence to support their points of view. I admire each of you for your passion in wanting to dissect the situation and discover new truths. It is due to people like you that engineers strive to make small and large improvements in technology over time.

From what I've read in this thread, we all seem to have a fairly clear idea about who does what, when, and why. Because we use different words to describe how we understand the situation, we, at least I, seem to assume that because we describe things differently, then we can't possibly be talking about the same thing, when in fact we are, but are observing this reality using our different experiences as reference points.

If we accept that we all understand what goes where and why, we seem to get bogged down in deciding how important each component is in the final outcome. A component that I might call banal, another might call significant, yet the end result is the same and we seem to agree on that.

I suppose that is what a forum is all about and it is this healthy tug and pull using different words to describe different things, or the same things, that give this forum its sense of sport.

This thread started with the suggestion that the XBR960 was more than it need be or less than it need be. The discussion has moved along with a microscopic look at the inner workings of tha' thing.

Without someone weighing in with some fresh measurements, we will be stuck debating the qualitative aspects and less the quantitative aspects.

It is the quantitative aspects that I enjoy the most. I'll leave it to others to take joy or pain in reading the qualitative aspects of the discussion.

I feel at this point that I have no new knowledge to share on this topic but I look forward to witnessing its evolution

This has been the most enjoyable thread since the ongoing discussion of the infamous "scrolling vertical bar at 1080i on Sony".

Thanks to you all for your participation thus far.

xrox

11-18-04, 08:02 PM

Just imagine holding the three guns RGB like a weapon and you had to focus the three beams through small holes with a white screen behind it.

You'd get a nice little "PREDATOR" pattern on the screen if you shot through a hole.

The point is the same pattern will show up no matter what hole you shoot through.

It would be impossible to change the order of the RGB triangle...........................

Anyway, think predator and have a good night! :) I have a headache from that stupid scope

kdb209

11-18-04, 08:54 PM

Looking at the nice graphic subysouth posted of the phosphor stripe,
I think I may have an explanation of the seemingly reversing RGB triads
down the stripe.

What if the dot mask is not a cartesian grid, but alternating rows with
openings offset by 1/2 a triad spacing.

What looks like reversing RGB Triads is actually an alternating pattern of
(for example):

1 - A triad with an apex of Red and a base of Green/Blue
2 - The base (Green/Blue) of the triad for the previous dot mask row and the apex
(Red) for the next dot mask row.

This gives the same pattern of phosphors as shown in the graphic, but the
orientation of RGB in the triad is fixed for all triads and the beam angle
becomes the sole detrmining factor in color selection

Originally posted by subysouth
I see the problem. There is some key event we're missing here. Clearly the guns are able to relocate the phosphors each sucessive triad but how can it light portions of two lines with the same beam in the same pass.

The beam shouldnt be in two places at once. But for the relocation of the phosphors in the stripe I could see the angle thing.

Unfortunately I havent seen a test pattern that shows a scan line seperation with more than one set of triad colors in two vertial stripes lit simultaneously.

Something is missing and I'm tapped out.

ss

gdg

11-19-04, 12:28 AM

As I've learned as an audiophile, regardless of the technology implemented, the proof is in the pudding. Often, widely divergent engineering approaches, paradoxically, lead to convergent results. Furthermore, in any consumer grade product the real art of the engineer is, not in producing perfection (impractical), but rather in balancing compromise in the most efficient manner. Since that is the reality of engineering, no amount of technical debate can truly ascertain the merit of a piece of technology. One needs comprehensive testing and end user evaluation.

That said, the most technically comprehensive testing for the consumer I've seen is done by the people at "Secrets of Home Theater and Hi-Fidelity". The work they did on DVD players set the review industry standard and was light years ahead of the competition. I'd sure love to see them step up and apply the same rigorous testing standards to the Sony kd34xbr960 (and maybe a few other CRTs just for comparisons sake).

gdg

11-19-04, 01:02 AM

I was just playing around with the suggestion that contrast (white level) should be backed off to between 30% and 40% (depending on source). I find that if I back off my contrast to 40% (from the 50% I was using) my shadow detail is a real problem. Using the Avia DVD , in order to bring the shadow detail up to a bare minimum standard I need to jack up brightness (black level) to about 65%. Does that seem reasonable?

My instinct is more along the lines of 45% contrast and 56% brightness.
(28/62, 35/62 respectively on Sony's scale)

subysouth

11-19-04, 01:48 PM

On a fresh view this day I am still tapped out as to how the guns address that dot mask screen.

I spoke to a tech at KDS this am and I wish I could say he explained it but he didnt. He was Indian and I was having trouble explaining my question, he was also puzzled as to why I wanted to know. :p

He did say that the set should be only lighting up a single horizontal line of triads per line and that when driven to a lower line rate it simply should turn off lines or not scan them. I ran my computer monitor down to its lowest resolution and sure enough the dead lines were obvious.

What we couldnt clear up was how the guns addressed sucessive rotated triads in a horizontal line but he did agree the guns did this and that I should be able to see that on my monitor. He did not know how they did it.

How the heck is this happening? Why are portions of more than one line of triads being lit?

Seldom do we run into a point in the internet era that is unexplainable. And how this set works is key to how its resolution is displayed. I sure would like to know but I am at a loss. As montreal said thanks to everyone who contributed and TIA for anyone who can step in and explain it.

ss

subysouth

11-19-04, 01:56 PM

Originally posted by kdb209
Looking at the nice graphic subysouth posted of the phosphor stripe,
I think I may have an explanation of the seemingly reversing RGB triads
down the stripe.

What if the dot mask is not a cartesian grid, but alternating rows with
openings offset by 1/2 a triad spacing.

What looks like reversing RGB Triads is actually an alternating pattern of
(for example):

1 - A triad with an apex of Red and a base of Green/Blue
2 - The base (Green/Blue) of the triad for the previous dot mask row and the apex
(Red) for the next dot mask row.

This gives the same pattern of phosphors as shown in the graphic, but the
orientation of RGB in the triad is fixed for all triads and the beam angle
becomes the sole detrmining factor in color selection

I am trying to understand this but I am becoming confused.

Are we only looking at this single line? Not the line above or below it? What are you addressing when you say row - same as a line?

You seem to be suggesting the beam is kinda bouncing up and down maybe? Taking portions of the row/line above and below while mainataining the same triangular orientation?

ss

subysouth

11-19-04, 02:14 PM

kdb's expanation is correct I believe.

DOH! The evidence is in the pic I linked above showing the three beams exiting the shadow mask. Look at the pattern of the holes on the dot mask itself. That lines up exactly with what I think kdb is saying.

That line I posted is only lit every other triad and dots of the top and bottom row of that stripe are lit in the line above and below.

Difficult to picture in action vs the apearture grille approach and more difficult to picture the actual scan lines in action as they are "interlaced" together.

ss

edit: So that single phosphor stripe I linked in a numerical(not actual) sense = 1.5 scan lines correct?

xrox

11-19-04, 02:16 PM

Originally posted by subysouth
What we couldnt clear up was how the guns addressed sucessive rotated triads in a horizontal line but he did agree the guns did this and that I should be able to see that on my monitor. He did not know how they did it.

How the heck is this happening? Why are portions of more than one line of triads being lit?

Seldom do we run into a point in the internet era that is unexplainable. And how this set works is key to how its resolution is displayed. I sure would like to know but I am at a loss. As montreal said thanks to everyone who contributed and TIA for anyone who can step in and explain it.
ss

The guns do not have to tagret specific dots. All they have to do is focus the three beams to a point that coincides with a mask hole or arpeture. Once that is complete then the laws of math and geometry take over.

That is why they space the mask at a specific disntance from the phosphors.

As long as the gun keeps it's focus then it just has to scan that focul point across the screen and the proper RGB seperation will occur.

subysouth

11-19-04, 02:23 PM

Originally posted by xrox
The guns do not have to tagret specific dots. All they have to do is focus the three beams to a point that coincides with a mask hole or arpeture. Once that is complete then the laws of math and geometry take over.

That is why they space the mask at a specific disntance from the phosphors.

As long as the gun keeps it's focus then it just has to scan that focul point across the screen and the proper RGB seperation will occur.

Well thats kinda the same thing. Old tv sets didnt have masks at all and worked the same way. If the the beams do hit the hole in the mask they will hit the phosphors, even if the mask werent there. They may also hit other phosphors to though. The mask cleans up the beam - kills the overage.

It was the interlacing of the triads thats the key as kdb posted I think.

kdb gets the Wile E. Coyote supergenius award for the day in my book.:)

ss

subysouth

11-19-04, 02:27 PM

Is anybody good with graphics programs?

If so could someone post a block of dot mask color triads with alternating lines turned off?

ss

xrox

11-19-04, 02:33 PM

Originally posted by subysouth
Well thats kinda the same thing. Old tv sets didnt have masks at all and worked the same way. If the the beams do hit the hole in the mask they will hit the phosphors, even if the mask werent there. They may also hit other phosphors to though. The mask cleans up the beam - kills the overage.

It was the interlacing of the triads thats the key as kdb posted I think.

kdb gets the Wile E. Coyote supergenius award for the day in my book.:)

ss

I didn't say he was incorrect. In fact he is completely correct. It is just what montreal and I have been saying all along. The combination of the mask and the beam angles provides color selection.

Without that you cannot make a color CRT!

xrox

11-19-04, 02:44 PM

To put it simply, my interpretation is that the single most important aspect of color CRT is the focus of the 3 beams to a single spot. If this is accomplished then whatever signal is sent from the red gun will excite only red dots and so on... (due to the angle dependence)

When one opening in the mask lets electons in from that focused beam there is an emmission with proper RGB seperation.

Therefore the mask can be variable (ie 800 holes or 1400 whatever) and the CRT will still work just fine. It is just that the 1400 hole mask will be able to more accurately accept the focused beams in regards to the original signal.

But it is still not perfect.

Cheers

kdb209

11-19-04, 02:46 PM

Hopefully this attempt at a proportional font diagram works:

[FONT=courier new]

Shadow Mask:

Row0...........O...........O...........O...........O...........
Row1.....O...........O...........O...........O...........O.....
Row2...........O...........O...........O...........O...........
Row3.....O...........O...........O...........O...........O.....
Row4...........O...........O...........O...........O...........

Phosphor Triads:

.........R1..G0..B0..R1..G0..B0..R1..G0..B0..R1..G0..B0..R1..
.......G1..B1..R2..G1..B1..R2..G1..B1..R2..G1..B1..R2..G1..B1..
.........R3..G2..B2..R3..G2..B2..R3..G2..B2..R3..G2..B2..R3..
.......G3..B3..R4..G3..B3..R4..G3..B3..R4..G3..B3..R4..G3..B3..

R1/G1/B1 - RGB Triad for Shadow Mask Row 1
R2/G2/B2 - RGB Triad for Shadow Mask Row 2
R3/G3/B3 - RGB Triad for Shadow Mask Row 3
etc

[/FONT]

The stripe you showed in your graphic contains the triads for one shadow mask line
interleaved with partial triads from the previous and next shadow mask lines -
Just take any 2 rows from the diagram above.

Originally posted by subysouth
I am trying to understand this but I am becoming confused.

Are we only looking at this single line? Not the line above or below it? What are you addressing when you say row - same as a line?

You seem to be suggesting the beam is kinda bouncing up and down maybe? Taking portions of the row/line above and below while mainataining the same triangular orientation?

ss

xrox

11-19-04, 02:51 PM

Originally posted by subysouth
Is anybody good with graphics programs?

If so could someone post a block of dot mask color triads with alternating lines turned off?

ss

No need to draw,

just look close at the link I already posted (Color Selection)

Look at the mask that matches the grill and the phosphor stripes. The mask opening alternate to match up with the correct triad.

http://www.uniklinikum-giessen.de/kis-ris-pacs/archiv/2001/mi1240.pdf

subysouth

11-19-04, 02:54 PM

Originally posted by xrox
I didn't say he was incorrect. In fact he is completely correct. It is just what montreal and I have been saying all along. The combination of the mask and the beam angles provides color selection.

Without that you cannot make a color CRT!

Without the part of the interlaced triads your explanation was incomplete and invalid. The locations of the three guns creating different angles of incidence was first brought up by me if you might scroll back.

The mask is not necessary in any case.

The question was, how does the dot mask set address sucessive triads in a single row? The answer is there arent single rows and the guns therefore dont. kdb I think explained that best.

But xrox, if you need some credit - you can have a Wile E. award too.:)

My thanks to all.

Now the interesting part is figuring resolution by trying to count triads. Its doable just slightly more complicated.

ss

dt_dc

11-19-04, 04:55 PM

The problem with graphics like the following:
http://www.infocellar.com/hardware/monitor/shadowmask-beams.gif
http://graphics.tomshardware.com/display/20011128/images/shadowmask.gif
Sorry ... image blocked ... See:
http://graphics.tomshardware.com/display/20011128/crt-01.html
(top graphic)

Is that they are implying something that is not true ...

That the beam coming from the gun is the exact same size as the holes ...

In the secord graphic above ...
1) move the mask up / down / sideways a little
2) make the beam (BEFORE it hits the mask) bigger or smaller than the holes

That's what's actually happening.

BUT WAIT! What if a beam is too big and spills on to a surrounding hole!?!

Doesn't matter ... it's still going to hit the correct colored dot / phosphor area.

BUT WAIT! What if a beam is too small and doesn't paint an entire dot!?!

Doesn't matter ... it'll paint the rest of the dot on the next pass.

I'm going to have to go back through this thread ... don't know how we came to the (incorrect) conclusion that the scan rate / mask / beam size are perfectly in synch.

xrox

11-19-04, 05:13 PM

Originally posted by dt_dc
The problem with graphics like the following:
http://www.infocellar.com/hardware/monitor/shadowmask-beams.gif
http://graphics.tomshardware.com/display/20011128/images/shadowmask.gif
Sorry ... image blocked ... See:
http://graphics.tomshardware.com/display/20011128/crt-01.html
(top graphic)

Is that they are implying something that is not true ...

That the beam coming from the gun is the exact same size as the holes ...

In the secord graphic above ...
1) move the mask up / down / sideways a little
2) make the beam (BEFORE it hits the mask) bigger or smaller than the holes

That's what's actually happening.

BUT WAIT! What if a beam is too big and spills on to a surrounding hole!?!

Doesn't matter ... it's still going to hit the correct colored dot / phosphor area.

BUT WAIT! What if a beam is too small and doesn't paint an entire dot!?!

Doesn't matter ... it'll paint the rest of the dot on the next pass.

I'm going to have to go back through this thread ... don't know how we came to the (incorrect) conclusion that the scan rate / mask / beam size are perfectly in synch.

I didn't know it was implied? (guess I missed it)

The size (width) of the beam is irrelevent because the mask hole sets the beam width after passing through it.

Up to 80% of the beam is absorbed by the screen

There is still a complete angle dependance.

As I said before it doesn't matter where the beam is.

P.S. - Also, good point abou the beam being wide enough to spill onto an adjacent hole. It will still hit the correct color due to angle dependence and this could be why we see partial dot excitation!

Cheers

dt_dc

11-19-04, 05:38 PM

Originally posted by xrox
I didn't know it was implied? (guess I missed it)

The size (width) of the beam is irrelevent because the mask hole sets the beam width after passing through it.Exactly ... couldn't agree more ... beam could be smaller ... beam could be larger ...

Subysouth told me that this thread had 'proved' the 1:1 beam/hole/dot size ratio ... and that my images posted here ( http://www.avsforum.com/avs-vb/showthread.php?postid=4683467#post4683467 ) couldn't possibly be accurate.

I think maybe it was in the following?[QUOTE]Originally posted by subysouthDOH! The evidence is in the pic I linked above showing the three beams exiting the shadow mask. Look at the pattern of the holes on the dot mask itself. That lines up exactly with what I think kdb is saying.

That line I posted is only lit every other triad and dots of the top and bottom row of that stripe are lit in the line above and below.
Here's a more 'accurate' picture:
http://static.howstuffworks.com/gif/tv-cathode.gif
http://static.howstuffworks.com/gif/tv-cathode.gif

Too ... many ... threads ...

subysouth

11-19-04, 05:44 PM

Originally posted by dt_dc
The problem with graphics like the following:
http://www.infocellar.com/hardware/monitor/shadowmask-beams.gif
http://graphics.tomshardware.com/display/20011128/images/shadowmask.gif
Sorry ... image blocked ... See:
http://graphics.tomshardware.com/display/20011128/crt-01.html
(top graphic)

Is that they are implying something that is not true ...

That the beam coming from the gun is the exact same size as the holes ...

In the secord graphic above ...
1) move the mask up / down / sideways a little
2) make the beam (BEFORE it hits the mask) bigger or smaller than the holes

That's what's actually happening.

BUT WAIT! What if a beam is too big and spills on to a surrounding hole!?!

Doesn't matter ... it's still going to hit the correct colored dot / phosphor area.

BUT WAIT! What if a beam is too small and doesn't paint an entire dot!?!

Doesn't matter ... it'll paint the rest of the dot on the next pass.

I'm going to have to go back through this thread ... don't know how we came to the (incorrect) conclusion that the scan rate / mask / beam size are perfectly in synch.

I dont think anyone said they are perfectly in synch, they are very close to perfectly in synch. The dot mask approach is more likely to hit the intended target than say the aperature grille approach however given all other things are equal.

1. Neither the gun nor the mask move. the electron beams move as I understand it. What are you saying there?

If the guns generally arent converging on a specific hole at a specific time, the set isnt functioning correctly. The fact that computer monitors generate razor sharp graphics down to .25mm shows that the vast majority of the time the guns are exactly where they need to be. It not perfect, but then what is?

ss

subysouth

11-19-04, 05:57 PM

Originally posted by dt_dc
Exactly ... couldn't agree more ... beam could be smaller ... beam could be larger ...

Subysouth told me that this thread had 'proved' the 1:1 beam/hole/dot size ratio ... and that my images posted here ( http://www.avsforum.com/avs-vb/showthread.php?postid=4683467#post4683467 ) couldn't possibly be accurate.

I think maybe it was in the following?
Here's a more 'accurate' picture:
http://static.howstuffworks.com/gif/tv-cathode.gif
http://static.howstuffworks.com/gif/tv-cathode.gif

Too ... many ... threads ...

Man I am honestly getting confused.

I dont know what youre talking about my saying anything 1:1 was proven. I believe 1 pixel per triad should be the norm and the native rate for all CRTs. But I never said it was - it isnt tho. I wish it was. ????

You were posting an example on a dot mask phoshor stripe. The pic above looks like a slot mask approach which is quite different(and the beam size to slot are totally out of dimension-the beams are larger than the opening and the beams are oriented incorrectly.)

Your example in the other thread appeared to show a single scan line lighting up a distance below a single scan line tall. CRTs AFAIK have a beam spot a minimum of a the dot pitch in diameter(they have to be by nature) and the holes in the slot mask are near this size as well. So how can you light up something narrower than the beam can be even by displacing the scan line? You can light up fraction of triads horozontally by cycling the gun off as ots passing but I dont see how you can cut the beam spot size in half. Meaning even if you move the scan line vertically on the image there will still be at least a line height minimum being painted.

??????

ss

dt_dc

11-19-04, 06:15 PM

Originally posted by subysouth
CRTs AFAIK have a beam spot a minimum of a the dot pitch in diameter(they have to be by nature)And ... here we are.

A CRT's beam spot can be smaller (or larger) than the dot pitch in diameter. Much bigger ... much smaller ... doesn't matter ...

subysouth

11-19-04, 06:36 PM

Originally posted by dt_dc
And ... here we are.

A CRT's beam spot can be smaller (or larger) than the dot pitch in diameter. Much bigger ... much smaller ... doesn't matter ...

The tech at KDS says beam spot is fixed when the set is built and will bloom slightly based on contrast etc but not much and not without problems. The beam spot is permanently set to be slightly larger than pitch on a direct view CRT. Thats why low line counts yield scan lines. If the beam spot were variable you could increase beam spot for lower line counts and always have a full screen. It doesnt happen. You get beam spot at triad pitch plus a little over-bleed(or possibly a lot of over-bleed in an aperature grille approach.)

Even beam spot on a seperate 3 gun array is barely variable and not without ill effects. The trick to properly scaling a 3-gun CRT array is getting a line count that matches the vertical size of line x beam spot.

ss

edit: And dt if you think about it, if the beam spot is smaller than the pitch you cant light all the phosphors in a triad in one pass. You couldnt do white without two passes and then youd run smack into that angular problem. And youre scanning rate would have to exceed your vertical screen/pitch just to cover the screen. I think at minimum(and maximum) pitch and beam spot size are basically very similar and set the day the set is built.

gdg

11-19-04, 07:01 PM

Have you reached any conclusions regarding the merits/drawbacks of Sony's new CRT technology? Or are you even talking about the Sony any more? (shadow mask, dot triad etc etc don't apply do they?)

Ps Without a basic understanding of the internal parts of a CRT you lost me a long time ago.:confused:

subysouth

11-19-04, 07:49 PM

Originally posted by gdg
Have you reached any conclusions regarding the merits/drawbacks of Sony's new CRT technology? Or are you even talking about the Sony any more? (shadow mask, dot triad etc etc don't apply do they?)

Ps Without a basic understanding of the internal parts of a CRT you lost me a long time ago.:confused:

Not really, but I for one have learned a lot.

The aperature grille on the Sony IMO is inherently more prone to vertical(and horizontal) bleed due to the lack of any metal dividers in the vertical(except a couple of stiffening wires) and minimal separtion in the horizontal.

However the Sony's undivided vertical stripe makes an argument of actual 1080 vertical resolution possible. Aperature grille sets are uniquely built to possibly support 1080.

The dot and slot mask sets are limited at least by the holes in their mask.

The best test would be an HD vertical resolution pattern.

ss

gdg

11-19-04, 09:57 PM

Originally posted by subysouth

.....The best test would be an HD vertical resolution pattern.

ss

Like I said, the guys at "Secrets" should start testing CRTs. I can't understand why they don't. There is a real niche, which they are ideally suited to fill, for rigorous technical analysis.

subysouth

11-20-04, 04:21 PM

Originally posted by gdg
Like I said, the guys at "Secrets" should start testing CRTs. I can't understand why they don't. There is a real niche, which they are ideally suited to fill, for rigorous technical analysis.

gdg, I read a couple of the display device reviews on their site and while they may delve deep in some other arenas, their display reviews are pretty non-technical.

In my experience so far, WSR and TPV are the most unbiased and skeptical reviewers(unless Joe Kane gets his hands on a particular device.) Maybe in the future they will ratchet up the testing to more explore actual resolution.

I sent them an e-mail asking as much. Maybe if more people did they would.

ss

gdg

11-20-04, 06:23 PM

You're right, they don't do much in the area of TVs, or in fact in anything other than DVD players. That said, just for the heck of it, you should check out their "Benchmark" dvd tests that show virtually everthing out their in a comprehensive and ranked chart. It's absolutely outstanding, and involves the most exhaustive set of tests I've ever seen. (there is a table near the top of the page I've linked to)

http://www.hometheaterhifi.com/cgi-bin/shootout.cgi?function=search&articles=all&type=&manufacturer=0&maxprice=0&deInt=0&mpeg=0

dt_dc

11-21-04, 03:12 AM

The beam spot is permanently set to be slightly larger than pitch on a direct view CRT.Incorrect.

CRT 101:
Beam spot size is based on scan rate. Height of screen / number of scan lines = ideal beam spot size*.

For example,
1280x1024p ... Hieght of screen / 1024 = beam spot size
1024x768p ... Height of screen / 768 = beam spot size

Beam spot size has absolutely nothing to do with mask / grill / pitch.

If you follow the path of a beam ... just for the heck of it, let's follow the red beam ... that beam is going to go all the way accross the screen, go down to the next line (for simplicity, we'll make this a progressive example), go all the way accross the screen ... and keep doing this for however many scan lines there are.

The beam is going to scan a line accross the screen ... scan line ...however many times neccessary ...

Like This:
http://members.cox.net/dt_dc/ScanLine1.GIF
Etc ... on down to the bottom of the screen ...

Beam spot size = height of screen / number of scan lines.

Let's say the above is the 768p example.

The 1024p example is going to have more scan lines ... smaller beam spot. Like this:
http://members.cox.net/dt_dc/ScanLine2.GIF
Note: I didn't do the exact calculations here for an exactly proportional image ... point is, beam spot is smaller for a higher scan rate.

To clear up some misconceptions from earlier in this thread ...

The red beam pictured above isn't somehow trying to 'miss' the blue and green phosphors. It isn't trying to only 'hit' the red phosphors. It isn't trying to somehow turn off and then only turn on when it's time for a red phosphor. The red beam takes the path above ... always 'on' ... all the way accross the screen ... line by line ... from top to bottom. It's the mask / grill that ENSURES that the red beam is only going to strike red phosphors ... NOT some sort of intentional aiming of the guns at red phosphors.

The red beam pictured above is hitting multiple triads at the same time! Yes, so what? We can get in to this later ... but this is actually a very good thing. It improves picture quality.
The tech at KDS says beam spot is fixed when the set is builtBeam spot is fixed when the set is built ... for each SCAN RATE.beam spot is fixed when the set is built and will bloom slightly based on contrastBlooming has absolutely NOTHING to do with beam spot size. Blooming is caused when contrast is set too high ... but not because the beam spot is 'too large'. Blooming is caused by the beam current being too high for the phosphors. I mean high as in quantity ... not location. You can think of it as the beam being too 'bright'. It over-excites the phosphors ... phosphors OUTSIDE the beam are creating light. Again, blooming is NOT because the beam spot is too large. I guess I'll have to explain this more in another post.Thats why low line counts yield scan lines. If the beam spot were variable you could increase beam spot for lower line counts and always have a full screen. It doesnt happen.It does happen. However, this is where the "ideal beam spot size*" above comes in. Based on the design of the CRT, there are limits to the min/max spot beam size. It all comes down to focus. It's a (relatively) simple matter to adjust focus on the beam and ... change the beam size. However, there are limits (built in to the CRT) how much you can do this. You basically start getting in to problems of consistancy / uniformaty / and sharpness.

Now, it is pretty complex to have to change the focus accross the entire screen as the beam is sweeping accross (and for each line). This is exactly what's required from a flat screen monitor. If a CRT wasn't able to 'adjust' beam size ... CRT flat screens would be impossible. You'd have a small beam in the middle of the screen ... large beam at the top / bottom / sides.

But ... scaling the beam spot size to some degree accross the entire screen ... no problem (within limits).

HOWEVER, even if a beam spot can't be adjusted to the ideal for the scan rate, it's going to travel as drawn above. It's Going to be centered within the white lines ... and either spill over (or fail to fill) a little. There's still absolutely NO inherent relationship to pitch size.The trick to properly scaling a 3-gun CRT array is getting a line count that matches the vertical size of line x beam spot.Yes ... which has absolutely nothing to do with the mask pitch.And dt if you think about it, if the beam spot is smaller than the pitch you cant light all the phosphors in a triad in one pass. You couldnt do white without two passesAnd why wouldn't the following look white?http://members.cox.net/dt_dc/TriadsSplit.GIForhttp://members.cox.net/dt_dc/TriadsPartial.GIF

Couple questions? Why do you think a CD front projector array beam size can be variable ... and a TV / Monitor's can't? What do you think happens when you change your PC montor's can rate between two resolutions where you can't see scan lines?

subysouth

11-21-04, 03:46 AM

Originally posted by dt_dc
Incorrect.

CRT 101:
Beam spot size is based on scan rate. Height of screen / number of scan lines = ideal beam spot size*.

For example,
1280x1024p ... Hieght of screen / 1024 = beam spot size
1024x768p ... Height of screen / 768 = beam spot size

Beam spot size has absolutely nothing to do with mask / grill / pitch.

If you follow the path of a beam ... just for the heck of it, let's follow the red beam ... that beam is going to go all the way accross the screen, go down to the next line (for simplicity, we'll make this a progressive example), go all the way accross the screen ... and keep doing this for however many scan lines there are.

The beam is going to scan a line accross the screen ... scan line ...however many times neccessary ...

Like This:
http://members.cox.net/dt_dc/ScanLine1.GIF
Etc ... on down to the bottom of the screen ...

Beam spot size = height of screen / number of scan lines.

Let's say the above is the 768p example.

The 1024p example is going to have more scan lines ... smaller beam spot. Like this:
http://members.cox.net/dt_dc/ScanLine2.GIF
Note: I didn't do the exact calculations here for an exactly proportional image ... point is, beam spot is smaller for a higher scan rate.

To clear up some misconceptions from earlier in this thread ...

The red beam pictured above isn't somehow trying to 'miss' the blue and green phosphors. It isn't trying to only 'hit' the red phosphors. It isn't trying to somehow turn off and then only turn on when it's time for a red phosphor. The red beam takes the path above ... always 'on' ... all the way accross the screen ... line by line ... from top to bottom. It's the mask / grill that ENSURES that the red beam is only going to strike red phosphors ... NOT some sort of intentional aiming of the guns at red phosphors.

The red beam pictured above is hitting multiple triads at the same time! Yes, so what? We can get in to this later ... but this is actually a very good thing. It improves picture quality.
Beam spot is fixed when the set is built ... for each SCAN RATE.Blooming has absolutely NOTHING to do with beam spot size. Blooming is caused when contrast is set too high ... but not because the beam spot is 'too large'. Blooming is caused by the beam current being too high for the phosphors. I mean high as in quantity ... not location. You can think of it as the beam being too 'bright'. It over-excites the phosphors ... phosphors OUTSIDE the beam are creating light. Again, blooming is NOT because the beam spot is too large. I guess I'll have to explain this more in another post.It does happen. However, this is where the "ideal beam spot size*" above comes in. Based on the design of the CRT, there are limits to the min/max spot beam size. It all comes down to focus. It's a (relatively) simple matter to adjust focus on the beam and ... change the beam size. However, there are limits (built in to the CRT) how much you can do this. You basically start getting in to problems of consistancy / uniformaty / and sharpness.

Now, it is pretty complex to have to change the focus accross the entire screen as the beam is sweeping accross (and for each line). This is exactly what's required from a flat screen monitor. If a CRT wasn't able to 'adjust' beam size ... CRT flat screens would be impossible. You'd have a small beam in the middle of the screen ... large beam at the top / bottom / sides.

But ... scaling the beam spot size to some degree accross the entire screen ... no problem (within limits).

HOWEVER, even if a beam spot can't be adjusted to the ideal for the scan rate, it's going to travel as drawn above. It's Going to be centered within the white lines ... and either spill over (or fail to fill) a little. There's still absolutely NO inherent relationship to pitch size.Yes ... which has absolutely nothing to do with the mask pitch.And why wouldn't the following look white?http://members.cox.net/dt_dc/TriadsSplit.GIForhttp://members.cox.net/dt_dc/TriadsPartial.GIF

Couple questions? Why do you think a CD front projector array beam size can be variable ... and a TV / Monitor's can't? What do you think happens when you change your PC montor's can rate between two resolutions where you can't see scan lines?

I dont think a CRT front projector changes beam spot size in a meaningful way except when you change power to it. The more power the more of the surrounding phosphors get washed with stray energy because of the lack of a mask to refine the beam. However there is an ideal line count on a FP that is a combo of no line overlap based on an essentially fixed beam spot size and a given color balance. Ask any ISF tuner what the possible resolution of a CRT front projector is and he'll tell you it depends on beam spot size inherent to the calibrated gun vs tube size.

The tech at KDS said beam spot size does not change and is similar to but slightly larger than pitch Do you have a link to something documenting this changing beam spot size? I cant take your word for it. I Google varying beam spot size and return zero hits. Thats a big deal so lets back that one up.

Lemme show you what I mean by blooming relative to power. The higher the intensity the beam the more it disperses outward from the edges of the hole in the shadow mask. I had never thought about it but, that may indeed be what causes blooming in the sense youre using it, I dont know. In any event blooming is not limited to that one use, I dont know If theyre linked but your reference is not how I intended it. Here's a pic of what I am talking about:

http://www.infocellar.com/hardware/monitor/aperture-dispersion.jpg

Also CRT color monitors existed before shadow masks so your statement that the mask is key to hitting any color phopshor is incorrect. The mask cleans up the shot but isnt key to it. The need for clear text on computer monitors lead to the development of the shadow mask.

ss

edit: What happens when the CRT increases resolution on the computer monitor? More of the entire field is covered. On my monitor in particular its rated to a maximum 1600x1200 but the lines fully overlap at about 1280x1024. Beyond that they over-overlap. So the beam spot size is a bit large for the actual pitch(typical btw per the KDS guy so the lower resolutions dont look to line deficient.) If you back the line count down, more and more of the screen goes black and the scan lines become larger. That wouldnt be happening if your graphs were correct. The screen IMO is acting in a way consistent with a slightly oversized compared to pitch but consistent beam spot size. The tech at KDS could be wrong or didnt understand my question but he seemed pretty firm about it. I asked him three times and made him explain it to me three times. This should be an answerable question though.

Also there are several tricks that CRT manufacurers use to equalize response across the screen. The beam spot naturally changes around the screen(flashlight effect) and the manufacturers try to reduce this as much as possible, I dont think they change the beam spot in a vertical resize like you are describing though. Here's some techniques for countering beam splatter:

-Make the back of the screen curved even though the front is flat.
-Reduce power to the center pixels of the screen
-Space the pixels at the edges farther apart but supply more power than the middle so the ovate beam spot creates a similar effect.
-Various proprietary techniques for focusing the beam spot away from ovate, not changing its size vertically across the screen though.

subysouth

11-21-04, 12:09 PM

Originally posted by dt_dc
HOWEVER, even if a beam spot can't be adjusted to the ideal for the scan rate, it's going to travel as drawn above. It's Going to be centered within the white lines ... and either spill over (or fail to fill) a little. There's still absolutely NO inherent relationship to pitch size.Yes ... which has absolutely nothing to do with the mask pitch.And why wouldn't the following look white?http://members.cox.net/dt_dc/TriadsSplit.GIForhttp://members.cox.net/dt_dc/TriadsPartial.GIF

Just continuing to try to sort this out.

I am assuming based on your pictures that these are both images of a dot mask screen.

I for one have been using beam spot size inappropriately. A better term would be beams strike area. The beam spot size on a direct view CRT is close to the opening size in the dot mask. The strike area is quite a bit larger than this and similar to pitch due to the spread caused by the locations of the guns to each other in space and being converged at the mask.

I am realizing another reason the above pics are impossible. The area lit by the electron beams at their fullest is limited by the unchanging hole in the shadow mask. Thats why no matter what it is, it cant be smaller than at least a pitch tall(again built in at the fixed gun locations and converged at the mask) because if it ever was lower than a pitch tall it would require the electron guns themselves relocating themselves closer to each other in space and changing the angles of incidence. And this would also require the beams to be smaller and converged inside the diameter of the shadow mask opening, something none of us have been willing to give the crt credit for doing.

Also in order for a dot mask set to generate white in the way you are displaying it it would take inter-line collaboration to resolve sub single triad height white lines and a sub triad beam strike size. That would seen to fly in the face of a the way a CRT is built. The partial two and single line shots above are impossible unless there is interline collaboration which opens up a whole seperate can of worms. The design of the dot mask set inherently as kdb descibed above interlaces the lines together, the signal processing I dont think views the lines that way, it views them as vertically stacked lines of a complete image. I cant see how it would know to take advantage of that overlap to create a wide version of white uses triads from seperate lines.

dt can you give us a field of one line on - one line off on the dot mask matrix? It will make what kdb described much clearer and show which parts go with which lines. Use red as the top of all triads for simplicity. I dont know which color is the actual to of each triad.

ss

gdg

11-21-04, 04:45 PM

[QUOTE]Originally posted by subysouth
about:

http://www.infocellar.com/hardware/monitor/aperture-dispersion.jpg

QUOTE]

I'm just following along here, mostly in a fog, since I have no basic technical. knowledge of how a CRT works. On the other hand I do have a BSc in Physics (from years ago) and, if memory serves me correctly, the concept of blooming, at least the way it's presented above, is fundamentally flawed. Photons and electrons behave like particles and travel in STRAIGHT lines. It could be argued that they do exhibit wave properties as well, but the behavior of electrons, when "fired" from an electron gun, can be most closely modeled along the lines of discrete particles (projectiles).

The misconception probably arises when viewing the way a spotlight appears to spread out from the source. This is an atmospheric effect and is actually a result of photons being scattered by particles in the atmosphere (and indeed the molecules that make up the atmosphere). As I understand it a CRT tube is a VACUUM.

Note: Another factor which results in a beam "appearing " to spread would be related to the construction of the reflecting surface used to project light from a point source. (not applicable in this case)

Geise

11-21-04, 07:45 PM

There are so many different thoughts on how a CRT actually works it scares me to think anyone would come to this forum for CRT advice :D I wish just one person here could be a CRT engineer, that would end all this :)

subysouth

11-21-04, 09:12 PM

gdg even in a vaccuum I think I could see the effect pictured although not as much as pictured. I think its physically feasible. I dont think its as pronounced as the picture though.

I think we are pecking away at it, but I agree it would be nice for an engineer to just come in and lay it all out.

ss

dt_dc

11-22-04, 01:41 AM

Originally posted by subysouth
edit: What happens when the CRT increases resolution on the computer monitor? More of the entire field is covered. On my monitor in particular its rated to a maximum 1600x1200 but the lines fully overlap at about 1280x1024. Beyond that they over-overlap. So the beam spot size is a bit large for the actual pitch(typical btw per the KDS guy so the lower resolutions dont look to line deficient.) If you back the line count down, more and more of the screen goes black and the scan lines become larger. That wouldnt be happening if your graphs were correct. The screen IMO is acting in a way consistent with a slightly oversized compared to pitch but consistent beam spot size.Yes ... your perfect world is something like this?
http://members.cox.net/dt_dc/TriadsPerfect.gif
And you're saying that when you run 1280x1024 ... the above is what it SHOULD look like ... however the beam is a little wider than pictured above ... so you're getting overlap? Is that correct so far?

I'm asking ... describe the path of the beam when you then run 1280x1024.

gdg

11-22-04, 02:21 AM

Originally posted by subysouth
even in a vaccuum I think I could see the effect pictured although not as much as pictured. I think its physically feasible.

ss

Actually no. The wave behavior of subatomic particles is manifest at the level of of the particles wavelength. This is many magnitudes smaller than what you are describing here. I only brought up the fact that sub atomic particles display both particle and wave properties because I figured someone might erroneously make the wrong connection. For our purposes and at the level CRT's are engineered at, for all intents and purposes, an electron may be considered a particle. Particles travel in straight paths unless influenced by an outside force (Newton). The edges of an opening cannot deflect a particle as you have described. ( A very small number of particles could conceivably bounce off one edge and across to the other side. A few might even go beyond the edge of the beam at the other side, but the flux density would be utterly insignificant.

dt_dc

11-22-04, 11:15 AM

Originally posted by subysouth
Also CRT color monitors existed before shadow masks so your statement that the mask is key to hitting any color phopshor is incorrect. The mask cleans up the shot but isnt key to it. The need for clear text on computer monitors lead to the development of the shadow mask.A direct view CRT without a shadow mask is called ... a black and white TV or monochrome monitor.

There were a few prototypes of other systems back when they were first implementing color TV.

However, when the first color TVs arrived in stores from RCA ... they contained ... shadow masks. Shadow masks were part of the 'RCA Color System' proposed and implemented by the FCC. Shadow masks were exactly what allowed a system to be (easily, cost effectively) built where the exact same TV signal could support both color televisions and black and white televisions.

Masks were not first implemented because if computer monitors. They (or grills) are integral to all current direct view (color) CRTs.

http://www.princetoninfo.com/200111/11114c01.html
http://www.novia.net/~ereitan/Color_Sys_RCA.html

subysouth

11-22-04, 12:05 PM

Originally posted by dt_dc
Yes ... your perfect world is something like this?
http://members.cox.net/dt_dc/TriadsPerfect.gif
And you're saying that when you run 1280x1024 ... the above is what it SHOULD look like ... however the beam is a little wider than pictured above ... so you're getting overlap? Is that correct so far?

I'm asking ... describe the path of the beam when you then run 1280x1024.

No.

You still dont have the lines correct as I understand them. They are interlaced. and in the area you have 2 lines are actually parts of three lines(one full line and two half lines.)

For arguments sake lets say all lines are composed of triads with red at the top(they are all composed of equally oriented triads I think, I just dont know which color is at the top and it doesnt really matter.) Again could you paint a one line on one line off based on all lines being composed of red dot topped triads as kdb described earlier?

ss

subysouth

11-22-04, 12:28 PM

Originally posted by dt_dc
A direct view CRT without a shadow mask is called ... a black and white TV or monochrome monitor.

There were a few prototypes of other systems back when they were first implementing color TV.

However, when the first color TVs arrived in stores from RCA ... they contained ... shadow masks. Shadow masks were part of the 'RCA Color System' proposed and implemented by the FCC. Shadow masks were exactly what allowed a system to be (easily, cost effectively) built where the exact same TV signal could support both color televisions and black and white televisions.

Masks were not first implemented because if computer monitors. They (or grills) are integral to all current direct view (color) CRTs.

http://www.princetoninfo.com/200111/11114c01.html
http://www.novia.net/~ereitan/Color_Sys_RCA.html

Both great reads. Here the quote I was basing my info on:

Masks - Refining the Electron Beams

Televisions have the same type of faceplate as monitors do - with a an inner coating of color phosphor. A problem occurren when they tried to use TV screen for computer monitors - the text was blurry. It seemed the CRT could not define crisp, clear edges. This is fine for television, since the text that is used is just credits at the end of a show, and usually it is quite large. Monitors require much tighter control.

The electron beams, upon leaving their respective Red Green and Blue guns, disperse slightly, and lose their sharp edges. It was found that if a sheet of metal was placed in front of the phosphor with tiny holes drilled into it - it "chopped off" the blurry edges of the circular beam and directed an exact, tight circle of energy onto the phosphor. This was known as a "shadow mask"

Today, manufacturers now place an ultra-thin metal covering behind the phosphor in all monitors, that directs and refines the electron beams. There are two types - shadow mask, and aperture grill. The shadow mask has been around a long time, and is simply a sheet of metal perforated with holes. The other type, introduced by Sony with their Trinitron Monitors, and now very common - is called the "Aperture Grill". As the name implies, a "grill" with vertical slats is laid down behind the phosphor. The metal strips allow the beams to penetrate as vertical slats that run up and down the screen.

I stand corrected, I still dont believe that the mask is a necessity however. I think it improves the image but is not a requirement in producing the signal. Sony's apearture grille is minimalistic - no break vertically and little horizontally.

ss

dt_dc

11-22-04, 12:53 PM

The tech at KDS said beam spot size does not change and is similar to but slightly larger than pitch
I for one have been using beam spot size inappropriately. A better term would be beams strike area. The beam spot size on a direct view CRT is close to the opening size in the dot mask. The strike area is quite a bit larger than this and similar to pitch due to the spread caused by the locations of the guns to each other in space and being converged at the mask.
Well then, at what point is 'beam spot size' ... or 'strike area' 'similar to but slightly larger than pitch'? The picture above shows a beam spot (with your terms) size equal to pitch ... and the 'strike area' limited only by the functionlity of the mask.
http://members.cox.net/dt_dc/TriadsPerfect.gif
Now you say ... no ... 'beam spot size' is actually about equal to actual holes in the mask and 'strike area' is equal to the pitch? Hole diameter is about 1/3 of pitch ... so somehow ... the 'strike area' is 3 times the size of the mask holes ... about 3 times (a tad smaller) the 'beam spot' in your terms? The beam is getting 3 times as large in the tiny amount of space between the mask and the phosphors ... yet the beam is remaining the same size BEHIND the mask? Well ... that's impossible. If the beam is expanding ... it's expanding ... at the same rate behind and in front of the mask. The gun would have to be just about the same distance from the mask as the mask is from the phosphors.

You're suggesting something like this:
http://members.cox.net/dt_dc/NotHappeningCRT.GIF
However, the guns on a CRT are MUCH further away than the mask is from the phosphors ... so that would require something like this:
http://members.cox.net/dt_dc/ImpossibleCRT.GIF
Well, this is impossible.

No ... the electron beams maintain a constant diameter from the time they leave the gun to the time they hit the mask. What passes through the mask maintains a contant diameter to the time it hits the phosphors. This is (as pointed out above) ... the whole point of the vacuum in a CRT.

subysouth

11-22-04, 12:58 PM

Originally posted by gdg
Actually no. The wave behavior of subatomic particles is manifest at the level of of the particles wavelength. This is many magnitudes smaller than what you are describing here. I only brought up the fact that sub atomic particles display both particle and wave properties because I figured someone might erroneously make the wrong connection. For our purposes and at the level CRT's are engineered at, for all intents and purposes, an electron may be considered a particle. Particles travel in straight paths unless influenced by an outside force (Newton). The edges of an opening cannot deflect a particle as you have described. ( A very small number of particles could conceivably bounce off one edge and across to the other side. A few might even go beyond the edge of the beam at the other side, but the flux density would be utterly insignificant.

Then why does the electron beam disperse at all in the relatively extremely short distance between the gun and the screen that it would require the mask at all? If the beam acts as ideally as you are suggesting, why not just engineer the beam spot sizes accordingly and dismiss the mask/grille entirely?

And recall its not just a single beam in most cases converging on that point it is all three.

ss

subysouth

11-22-04, 01:08 PM

Originally posted by dt_dc
Well then, at what point is 'beam spot size' ... or 'strike area' 'similar to but slightly larger than pitch'? The picture above shows a beam spot (with your terms) size equal to pitch ... and the 'strike area' limited only by the functionlity of the mask.
http://members.cox.net/dt_dc/TriadsPerfect.gif
Now you say ... no ... 'beam spot size' is actually about equal to actual holes in the mask and 'strike area' is equal to the pitch? Hole diameter is about 1/3 of pitch ... so somehow ... the 'strike area' is 3 times the size of the mask holes ... about 3 times (a tad smaller) the 'beam spot' in your terms? The beam is getting 3 times as large in the tiny amount of space between the mask and the phosphors ... yet the beam is remaining the same size BEHIND the mask? Well ... that's impossible. If the beam is expanding ... it's expanding ... at the same rate behind and in front of the mask. The gun would have to be just about the same distance from the mask as the mask is from the phosphors.

You're suggesting something like this:
http://members.cox.net/dt_dc/NotHappeningCRT.GIF
However, the guns on a CRT are MUCH further away than the mask is from the phosphors ... so that would require something like this:
http://members.cox.net/dt_dc/ImpossibleCRT.GIF
Well, this is impossible.

No ... the electron beams maintain a constant diameter from the time they leave the gun to the time they hit the mask. What passes through the mask maintains a contant diameter to the time it hits the phosphors. This is (as pointed out above) ... the whole point of the vacuum in a CRT.

The strike area is caused by the divergence of the three beams after exiting the mask. Assuming the beam spot is similar in diameter to a SINGLE phosphor dot, the collective stike areas of the three beam spots are 3x the area of a single beam spot. The three beams converge and are trimmed by the shadow mask then diverge after exiting the shadow mask to strike a single phosphor triad - hopefully.

The problem with your pic is as I posted above. Your are demonstrating lighting triads of three seperate lines with a single line pass. It cant be done the way you have it posted because of the angular problem and the fact that there arent holes in the shadow mask behind all the triads of that line at that level. The locations of the three phosphor dots relative to each other doesnt change we now know, meaning the colrs of each lit triad in identical in location. The key is understanding the seperate triad lines is that they are half-interlaced and all oriented identically as kdb explained earlier. I am thinking you dont understand this.

When you post a field of one line on - one line off it will become clear.

And I have absolutely no idea what your last two images depict, so I dont know that I am suggesting it either.

ss

dt_dc

11-22-04, 01:43 PM

Televisions have the same type of faceplate as monitors do - with a an inner coating of color phosphor. A problem occurren when they tried to use TV screen for computer monitors - the text was blurry. It seemed the CRT could not define crisp, clear edges. This is fine for television, since the text that is used is just credits at the end of a show, and usually it is quite large. Monitors require much tighter control.This is all true. However, the conclusions the author draws are horribly innacurate.The electron beams, upon leaving their respective Red Green and Blue guns, disperse slightly, and lose their sharp edges. It was found that if a sheet of metal was placed in front of the phosphor with tiny holes drilled into it - it "chopped off" the blurry edges of the circular beam and directed an exact, tight circle of energy onto the phosphor. This was known as a "shadow mask".1) Shadow masks have been around since color TV was invented. They aren't 'new' or 'only required' with PC monitors.
2) All direct-view CRT sets sold from the introduction of color TV to the time the PC monitor was introduced contained shadow masks.
3) So all TVs were capable of "chopping off" the blurry edges of the circular beam and direct an exact, tight circle of energy onto the phosphor (as the author would put it). According to the author, this is adequate for presenting sharp text (yet they weren't).
4) Therefore, the shadow mask must NOT have been invented merely to make text sharp on PC monitors.
5) The author's conclusions are false.

I wouldn't put too much stock in this quote ... the author doesn't seem to know what they are talking about.

However, yes, the shadow masks they used for televisions were not sufficient for PC monitors. Text did appear blurry when displayed on standard televisions. The reason for this is that the shadow masks were too course. Sharp text requires finer shadow masks ... smaller dots ... more of them.

xrox

11-22-04, 02:02 PM

Sorry if I'm stating the obvious here but I want to make sure I have this clear:

1. Beam Angle (to the mask): determines color selection and purity

2. Beam Angle (to other beams): This is called convergence or focus, all three beams must land on a Single hole on the mask. Better convergence means better color purity

3. Beam width : is irrelevant unless the beam width exceeds the distance between successive holes on the mask

Cheers

subysouth

11-22-04, 02:15 PM

Originally posted by dt_dc
This is all true. However, the conclusions the author draws are horribly innacurate.1) Shadow masks have been around since color TV was invented. They aren't 'new' or 'only required' with PC monitors.
2) All direct-view CRT sets sold from the introduction of color TV to the time the PC monitor was introduced contained shadow masks.
3) So all TVs were capable of "chopping off" the blurry edges of the circular beam and direct an exact, tight circle of energy onto the phosphor (as the author would put it). According to the author, this is adequate for presenting sharp text (yet they weren't).
4) Therefore, the shadow mask must NOT have been invented merely to make text sharp on PC monitors.
5) The author's conclusions are false.

I wouldn't put too much stock in this quote ... the author doesn't seem to know what they are talking about.

However, yes, the shadow masks they used for televisions were not sufficient for PC monitors. Text did appear blurry when displayed on standard televisions. The reason for this is that the shadow masks were too course. Sharp text requires finer shadow masks ... smaller dots ... more of them.

In the grand scheme of things its a minor issue. The shadow mask is a refining tool only. The fact that Sony builds sets with a negligible mask is evidence of that.

Larger issues abound.

-Does beam spot resize for multiples rates or does beam spot stay consistant regardless of scan rate. You have said it changes but again I have searched and found nothing supporting this. Have you found something supporting this? This is a huge issue in CRT function.

-Do you understand what a scan line comprises on a dot mask set? You have posted several graphics which show a scan line lighting all of one line and parts of two others. Do you understand what triads are affected on an individual scan line?

ss

subysouth

11-22-04, 02:20 PM

Originally posted by xrox
Sorry if I'm stating the obvious here but I want to make sure I have this clear:

1. Beam Angle (to the mask): determines color selection and purity

2. Beam Angle (to other beams): This is called convergence or focus, all three beams must land on a Single spot on the mask. Better convergence means better color purity

3. Beam width : determines scan line width

Cheers

2. I would put hole where you said spot.

I agree with all those accept 3.

http://www.infocellar.com/hardware/monitor/shadowmask-beams.gif

Each of the incoming beams is an inidivual beam spot, the strike area is comprised of three beam spots. I am used to using beam spot in reference to FPs which use 3-tube arrays which only have the single gun to each tube. Strike area and beam spot size are equal on single color tubes and B&w sets.

ss

dt_dc

11-22-04, 02:23 PM

Originally posted by subysouth
The key is understanding the seperate triad lines is that they are half-interlaced and all oriented identically as kdb explained earlier. I am thinking you dont understand this.

When you post a field of one line on - one line off it will become clear.I see what you and kdh are saying. It isn't right ... but it's going to take some time to go over this point by point so ...

I think the keys to showing this are going to be:
1) What happens when I switch scan rates on the display?
2) How can I get 'overlapping scan lines' in your example above at 1600x1200 ... a potential 'gap' between scan lines at 800x600 ...
3) What happens when I fine-tune some of the controls (Zoom/Overscan ... HPOS ... HSIZ ... VPOS ... VSIZ ... Rotation ... Pincusion ... etc.

Anyway, in the mean time ...http://www.arcadecontrols.com/files/Miscellaneous/crtfaq.htm
(From: Bob Myers (myers@fc.hp.com).)

Here is where some words of explanation are in order.

What many people fail to realize is that the phosphor triads of the screen *do not* correspond to pixels in the image; they are not kept in alignment with the image pixels/lines/whatever, nor is there are reason for them to be.Unfortunately, I don't think the above link goes into the detail needed to show that point clearly ...

Be back soon ...

dt_dc

11-22-04, 02:32 PM

Originally posted by xrox
all three beams must land on a Single spot on the maskThis is very wrong. Beams can (and usually do) span multiple holes in the mask. On a typical PC monitor beams span 2 ... 3 ... often even more holes in the mask. This is very desireable. It improves the quality of the picture. When beam size starts to get smaller ... and approach the size of holes in the mask ... detail starts to get lost. Typical analog color TVs are set up so that beam size is only slightly larger than mask hole size (1.25x, 1.5x, etc). That's why text appears 'blurry' on them. Finer masks were needed for PC monitors ... allowing beam size 2x, 3x, etc. the size of holes in the mask were needed to get the 'sharp' detail of PC monitors.

xrox

11-22-04, 02:32 PM

Originally posted by subysouth
2. I would put hole where you said spot.

I agree with all those accept 3.

ss

3 would only be correct if the beam diameter was larger than the distance between successive mask holes. Below that diameter the width is determined by the combination of 1 and 2

I will edit my post

Thanks.

xrox

11-22-04, 02:34 PM

Originally posted by dt_dc
This is very wrong. Beams can (and usually do) span multiple holes in the mask. On a typical PC monitor beams span 2 ... 3 ... often even more holes in the mask. This is very desireable. It improves the quality of the picture. When beam size starts to get smaller ... and approach the size of holes in the mask ... detail starts to get lost. Typical analog color TVs are set up so that beam size is only slightly larger than mask hole size (1.25x, 1.5x, etc). That's why text appears 'blurry' on them. Finer masks were needed for PC monitors ... allowing beam size 2x, 3x, etc. the size of holes in the mask were needed to get the 'sharp' detail of PC monitors.

Sorry dt_dc I think you misunderstood me. I said on the mask, not on the phosphors.

The threee beams must converge onto the mask. they never do perfectly however!

dt_dc

11-22-04, 02:37 PM

Originally posted by xrox
Sorry dt_dc I think you misunderstood me. I said on the mask, not on the phosphors.

The threee beams must converge onto the mask. they never do perfectly however! No misunderstanding ... the beam spans multiple holes on the mask. This improves picture quality and is required for 'sharp text'.

xrox

11-22-04, 02:48 PM

Originally posted by dt_dc
No misunderstanding ... the beam spans multiple holes on the mask. This improves picture quality and is required for 'sharp text'.

I'd have to disagree. Unless you are describing beam width being large enough to cover multiple holes (then I agree). But what I am saying is that all threee RGB beams are focused so all beams come together on one area (convergence). The size of that area may span several holes......

here is my theory again followed by a proof.

1. Beam Angle (to the mask): determines color selection and purity

2. Beam Angle (to other beams): This is called convergence or focus, all three beams must land on a Single hole on the mask. Better convergence means better color purity

3. Beam width : is irrelevant unless the beam width exceeds the distance between successive holes on the mask

Dot pitch: 0.3 mm
| |
_____________________________ Phosphor screen
G B R G B R G B R G B R G B ^
\|/ 15 mm
- ----- ----- ----- ----- --------- Shadow mask
/|\ ^
/ | \ |
/ | \ 350 mm
/ | \ |
/ | \ v
B-gun G-gun R-gun ---------------- Electron guns
| |
Gun pitch: 7 mm

and some more reading:

4.18) Principles of purity and convergence adjustment

Purity involves bending all 3 of the beams so that they cross the space
between shadow mask and screen at the proper angle and will land at a
different place on the phosphors. Convergence involves adjusting the aim of 1 or 2 of the beams at a different angle so that they all land at the same
place on the mask.

Dynamic convergence circuitry is now virtually non-existent, except in high
resolution monitor tubes and in Sony Trinitron tubes (they require a very
basic horizontal convergence). All other tubes have the convergence
correction built into the design of the tube and the coil. Sony has chosen a
different trade-off between price and performance (which includes also
sharpness).

Most CRTs have a series - usually 3 pairs - of ring magnets mounted on the
neck near the socket end. These are used for part of the purity adjustment
and static convergence. (Coarse purity is set by the position of the yoke and
dynamic convergence is set by the tilt of the yoke.) These rings consist of
multi-pole magnets which due to their field configuration are able to affect
the electron beams from the 3 guns in different ways.

subysouth

11-22-04, 03:00 PM

Originally posted by dt_dc
I see what you and kdh are saying. It isn't right ... but it's going to take some time to go over this point by point so ...

I think the keys to showing this are going to be:
1) What happens when I switch scan rates on the display?
2) How can I get 'overlapping scan lines' in your example above at 1600x1200 ... a potential 'gap' between scan lines at 800x600 ...
3) What happens when I fine-tune some of the controls (Zoom/Overscan ... HPOS ... HSIZ ... VPOS ... VSIZ ... Rotation ... Pincusion ... etc.

Anyway, in the mean time ...Unfortunately, I don't think the above link goes into the detail needed to show that point clearly ...

Be back soon ...

So how would you suggest the beams act to light all the phosphors in a continuous row? I think you are still where I was several days ago thinking the beams rotated or cycled. The guns dont rotate though, that was the inherent problem, you cant light an inverted and noninverted triangle sequentially.

Think about it youll get it.

kdb's explanation solves all the address issues and is also graphically played out in the picture above. Note the staggered holes in the mask. Picture how and where the beams fall following that pattern with a fixed three part gun. If your pic were correct there would be holes vertically aligned with each other in successive lines AND you would still have to figure out how it would do inverted triangles sequentially with non-moving guns.

ss

edit: Picture it just like I said above, all non-inverted triads with red at the top are addressable triads. That gives you the scan lines.

subysouth

11-22-04, 03:03 PM

Originally posted by dt_dc
No misunderstanding ... the beam spans multiple holes on the mask. This improves picture quality and is required for 'sharp text'.

Covering multiple holes on the mask(feeding multiple triads) leads to less diefined text not more. The more discrete the info the sharper the text. More hole coverage with the same info = less discrete.

ss

subysouth

11-22-04, 03:05 PM

Originally posted by xrox
I will edit my post

Thanks.

I now completely agree.:)

ss

xrox

11-22-04, 03:38 PM

Here is a little graphic of my interpretation. The angles have been exagerated to show more spatial seperation.

The angle between each beam and the mask determine color selection and the angle between the beams themselves is called convergence. All three beams land on the same area on the the mask.

Perfect convergence would mean the exact centre of each beam intersect at the mask

Cheers

dt_dc

11-22-04, 04:20 PM

Just looking over my pictures above ... realized I had left something out ...

This is actually the exact same thing that ss and kdb have above so I didn't think to include it ... but ...

Looking from the front of the CRT ...
http://members.cox.net/dt_dc/FullCRT.GIF
Where the shaded white-ish dots are the holes in the shadow mask ...

And the colored dots are the phosphors ...

Electron beams are going to be coming straight(ish) at us (not shown yet) ...

This is basically an exact graphical representation of what kdb posted earlier ...

No arguments so far I hope.

subysouth

11-22-04, 04:29 PM

You nailed it. The opening loactions compared to the triads will vary across the screen, but for purposes of demonstration, thats correct.

Now you can see what a line is. A horizontal row of the lit triads.

ss

dt_dc

11-22-04, 05:33 PM

Originally posted by subysouth
The opening loactions compared to the triads will vary across the screen, but for purposes of demonstration, thats correct.Yes absolutely ...dt_dc - yes, I'm quoting myself
Electron beams are going to be coming straight(ish) at us ...And one other clarification, sorry ... the electron beams are coming straight-ish as us but at a very slight angle so the right beams hit the right colored phosphors. I just want to make sure that no one thinks I need to 'space out' the mask holes and phosphor dots so they don't overlap when looking at the CRT straight-on ...
ss
Unless you are describing beam width being large enough to cover multiple holes (then I agree). But what I am saying is that all threee RGB beams are focused so all beams come together on one area (convergence). The size of that area may span several holes......Yes, I agree with your definition of convergence. All three beams have to hit the same area of the mask at the same time.

I am surprised you agree that the electron beam CAN be large enough to cover multiple holes. I was thinking that you were arguing that a beam can only strike one (and only one) mask hole at a time.

Yes, I'm saying the beam CAN be large enough to cover multiple holes. Ok so far?

Now, where we are (still) disagreeing ...

You are saying that the beam HAS to cover an entire mask hole (or some multiple 2x, 3x) exactly. It must entirely cover the hole as it passes it. Curious as to why you think this ... I think I can see the basis in some sort of attempt to perfectly match each triad to a pixel in the original source ... and some hideously complex mechanics if this isn't the case ... but don't worry ... I can go back through the thread and see where you came to this.

I am saying the beam doesn't have to cover an entire mask hole. It doesn't have to be a perfect multiple. It can cover 1.5 holes ... and that is quite allright. The beam(s) just happily scan across the shadow mask in a straight line and the rest is taken care of. If a beam only partially fills a hole (and only lights part of a phosphor triad) ... that's fine because it will fill in the rest on the next pass ... the next scan line.

I'll get to this disagreement in my next post ... just want to make sure to find the common point of agreement / disagreement ...

xrox

11-22-04, 05:48 PM

Originally posted by dt_dc

Now, where we are (still) disagreeing ...

You are saying that the beam HAS to cover an entire mask hole (or some multiple 2x, 3x) exactly. It must entirely cover the hole as it passes it. Curious as to why you think this ... I think I can see the basis in some sort of attempt to perfectly match each triad to a pixel in the original source ... and some hideously complex mechanics if this isn't the case ... but don't worry ... I can go back through the thread and see where you came to this.

I am saying the beam doesn't have to cover an entire mask hole. It doesn't have to be a perfect multiple. It can cover 1.5 holes ... and that is quite allright. The beam(s) just happily scan across the shadow mask in a straight line and the rest is taken care of. If a beam only partially fills a hole (and only lights part of a phosphor triad) ... that's fine because it will fill in the rest on the next pass ... the next scan line.

I'll get to this disagreement in my next post ... just want to make sure to find the common point of agreement / disagreement ...

you talkin to me? :)

We are just confusing each others interpretations. I have never said what you say here. I totally agree with your interpretations, I just stated it with different words.

The beam width is IRRELEVANT when it comes to color selection. It can cover 30 holes or 0.25 holes and still only hit the correct color as long as the beam angle to the mask is correct!

Cheers :)

dt_dc

11-22-04, 06:31 PM

Originally posted by xrox
you talkin to me? :)

We are just confusing each others interpretations. I have never said what you say here. I totally agree with your interpretations, I just stated it with different words.

The beam width is IRRELEVANT when it comes to color selection. It can cover 30 holes or 0.25 holes and still only hit the correct color as long as the beam angle to the mask is correct!Yes ... I agree with this. And, going back over your original 1, 2, 3 list ...1. Beam Angle (to the mask): determines color selection and purity

2. Beam Angle (to other beams): This is called convergence or focus, all three beams must land on a Single spot on the mask. Better convergence means better color purity

3. Beam width : determines scan line widthSorry, I read 'spot' as mask-hole. With the clarification above, I completely agree with this list (except that focus is different from convergence ... however that is a minor point).

The new list ... however ...2. Beam Angle (to other beams): This is called convergence or focus, all three beams must land on a Single hole on the mask. Better convergence means better color purity

3. Beam width : is irrelevant unless the beam width exceeds the distance between successive holes on the mask#2 now seems to contradict "The beam width is IRRELEVANT when it comes to color selection. It can cover 30 holes or 0.25 holes and still only hit the correct color as long as the beam angle to the mask is correct" however. I don't understand why beam width is irrelevant ... yet the beam must land on a single hole in the mask. I agreed with the first version ... I don't agree with the second. I think ss has the opposite opinion (he agrees with the second version but not the first).

#3 Again, I agreed with the first version, but not the second. Are you saying beam width CAN'T be wider than the space between two holes in the shadow mask ... or that beam width doesn't matter UNTILL the beam is wider than the space between two holes in the shadow mask?

xrox

11-22-04, 06:35 PM

Originally posted by dt_dc
Yes ... I agree with this. And, going back over your original 1, 2, 3 list ...Sorry, I read 'spot' as mask-hole. With the clarification above, I completely agree with this list (except that focus is different from convergence ... however that is a minor point).

The new list ... however ...#2 now seems to contradict "The beam width is IRRELEVANT when it comes to color selection. It can cover 30 holes or 0.25 holes and still only hit the correct color as long as the beam angle to the mask is correct" however. I don't understand why beam width is irrelevant ... yet the beam must land on a single hole in the mask. I agreed with the first version ... I don't agree with the second. I think ss has the opposite opinion (he agrees with the second version but not the first).

#3 Again, I agreed with the first version, but not the second. Are you saying beam width CAN'T be wider than the space between two holes in the shadow mask ... or that beam width doesn't matter UNTILL the beam is wider than the space between two holes in the shadow mask?

Just word confusion, sorry!

Maybe "area" is a better word.

All that matters is that the centre of each beam intersects (or as closely intersects) at the mask.

:) sound better?

dt_dc

11-22-04, 06:37 PM

Unless you are describing beam width being large enough to cover multiple holes (then I agree). But what I am saying is that all threee RGB beams are focused so all beams come together on one area (convergence). The size of that area may span several holes......Sorry ... I attributed this quote to ss instead of xrox earlier.

ss - I take it you are still saying that the electron beam must hit one (and only one) hole in the shadow mask at the same time?

dt_dc

11-22-04, 06:38 PM

Originally posted by xrox
All that matters is that the centre of each beam intersects (or as closely intersects) at the mask.Yes ... this I agree with 100%!

Artwood

11-22-04, 06:43 PM

Let me ask all of you Direct-view CRT geniuses a question: if Sony were manufacturing DLPs now and had never decided to go the Rear Projection LCD route would we be seeing better Picture Quality in Direct-view CRT sets today? I think the answer to that question is an unequivocable yes. The only way that I think there will be anymore improvement in Direct-view CRT is if Samsung or LG puts money into narrower CRTs with great Picture Quality. If the Picture Quality isn't better than the Sony 34XBR960 and if the screen size of the sets aren't at least as big then the answer to the original question of this thread will be: The 34XBR960 NEEDED 1400 lines(whether this is true or not it doesn't matter) to establish the superiority of Sony in Direct-view displays. This will be the final chapter in Direct-view resolution unless someone else can challenge Sony. I wish we could have both MORE resolution and LARGER sizes of Direct-view CRT, but that is probably a pipe dream. If you want to blame anybody blame TI who alone makes DLP chips, Sony who is so greedy they won't buy them from TI and want to make ALL the money and Rear Projection LCD which even though it has less Picture Quality than Direct-view CRT--makes Sony MORE Money. Also blame the naysayer posters who aid Sony by propogating the ridiculous notion that larger size Direct-view is impossible. It isn't.

PaulGo

11-22-04, 07:05 PM

Sony will soon be producing a LCoS (SXRD) derivative a 70" RPTV that list for $10,000 and does 1080p. I think ultimately it will replace the Sony LCD RPTVs. They have front projectors using this technology that has won critical acclaim for the picture quality. The RPTV (pre-production unit) was recently demoed and received great reviews. I think Sony is trying to go upscale and sell premium products (at a premium price).

Artwood

11-22-04, 09:41 PM

If they are that would be a good strategy to pursue. I just wish if they were going to go high end why not give us a 36-inch version of the XBR960? I think Sony has the technological prowess to accomplish the feat and since most of the action in Direct-view will be coming from Korea and China in low priced models why not see if you can make things just a little bit larger. I'll agree that another 40-inch 4:3 set would probably be too large, but I think if anybody could make a quality 38-inch Widescreen it would be Sony and I think that size would please alot of people--especially if they could give it a Microfine sort of tube. I think that that would be the ultimate Direct-view set.

gdg

11-22-04, 10:24 PM

Originally posted by subysouth
Then why does the electron beam disperse at all in the relatively extremely short distance between the gun and the screen that it would require the mask at all? If the beam acts as ideally as you are suggesting, why not just engineer the beam spot sizes accordingly and dismiss the mask/grille entirely?

And recall its not just a single beam in most cases converging on that point it is all three.

ss

I will speculate based purely on logic.

I suspect that the shadow mask is not attempting to compensate for beam dispersion, but rather, for inaccuracies in the aim of the gun. Making the beam a little too wide and then only allowing the portion through that is directly on target would allow for a wider range of tolerances in both, gun construction and tracking ability. It would also compensate for other variables (such as stray fields) that might deflect the beam slightly.
Once again, this is just an educated guess on my part.;)

subysouth

11-22-04, 10:42 PM

Originally posted by dt_dc
Sorry ... I attributed this quote to ss instead of xrox earlier.

ss - I take it you are still saying that the electron beam must hit one (and only one) hole in the shadow mask at the same time?

I think the term is SHOULD not must. The tech at KDS said its not uncommon for the beam to cover more than one shadow mask hole at a time. But its NOT a good thing, its a lack of build quality thing. As I understand it based on waht he said, is it will fully strike one line and maybe partially two others, but the intent is one line only.

Getting to things I have a problem with still:

The sub-triad line graphs you posted earlier are still incorrect IMO. Only a misalignment of the beam vertically with the openings will yield a half covered phosphor dot vertically. If this occurs, the beam will be half dotting the same color in the full scan line above, if not slightly more. The gun cant cut its own height in half, at minimum ultimately a pitch height is gonna be covered at all times, likely a shade more per the KDS guy. They always want to make the area where the beam strikes the back of the mask larger than the mask opening so their not erring on the side of losing even more light output I am thinking.

And segueing into the next part. I still have no reason to believe the beam spots resize to cover more scan lines at varying line rates.

Those are still the points of contention, being able to resize beam spot size and being able to do fractions of a pitch in height.

ss

subysouth

11-22-04, 10:47 PM

Originally posted by gdg
I will speculate based purely on logic.

I suspect that the shadow mask is not attempting to compensate for beam dispersion, but rather, for inaccuracies in the aim of the gun. Making the beam a little too wide and then only allowing the portion through that is directly on target would allow for a wider range of tolerances in both, gun construction and tracking ability. It would also compensate for other variables (such as stray fields) that might deflect the beam slightly.
Once again, this is just an educated guess on my part.;)

Mechanics of electrons is just not my balliwick but with that many converging and hitting the edges of the hole in the mask, even as small as they are there has to be some effect on the ones making it through the mask. And the mask surface is also emitting some x-rays from all that bombardment. I would be really curious that furious praticle/ray traffic around the shadow mask opening under that bombardment.

But again probably tangential to our larger issues anyway.

ss

PaulGo

11-23-04, 09:59 AM

"but I think if anybody could make a quality 38-inch Widescreen it would be Sony"

The current technology makes these sets just too heavy so many people will not opt for this. The cost of developing another tube size is considerable and even charging a premium a company would not be able to recover their costs if it did not have wide acceptance. Most people today would prefer a LCD if the cost was about the same. Their are however some companies developing thinner lighter weight tube sets, if this catches on you may see the tube based market revitalized.

dt_dc

11-23-04, 01:47 PM

Originally posted by subysouth
The sub-triad line graphs you posted earlier are still incorrect IMO. Only a misalignment of the beam vertically with the openings will yield a half covered phosphor dot vertically.Allright ... looking back over this thread ... I now see where ss's and my interpretation diverted dramatically.

ss:
You are attempting to make each electron beam hit the exact same spot/hole on the shadow mask at the exact same time. 'Perfect' convergence for you would mean each beam hitting the same hole at the same time. Those pictures (from various How CRT Works sites) posted earleir (seem to) show that. It (at first) seems to make alot of sense.

I can actually see where you came to this ... I actually almost fell in to this trap thinking it over ...

dt:
The beams aren't aimed at the same stop/hole on the mask ... they are aimed at exact same area of phosphors. Ie, without the mask ...
I see 'perfect' convergence as each electron beam aimed at the exact same spot/area of the phosphor area.

The mask makes sure each beam hits a correctly colored phosphor. However, if the mask wasn't there ... and you froze the electron beams at a single point in time ... you'd get a nice perfect O on the screen (at the phosphor area).

Ok ... now I see where we are.

I'll both:
- start working backwords from ss's point of view and show why it can't be right
- start working forwards from my point of view and show why it is right.

Originally posted by subysouth Those are still the points of contention, being able to resize beam spot size and being able to do fractions of a pitch in height.[/B]Yes, I'm getting to those ...

I wanted to track down our base disagreement first ... and track through this thread and see how you came to your conclusions. Sorry ... I seem to be at a much lower post-per-minute than yourself. :)

This idea of "the beams are aimed at a single mask hole" vs. "the beams are aimed at a single area on the phosphor screen" seems to be at the heart of it.

xrox

11-23-04, 03:19 PM

Originally posted by dt_dc
dt:
The beams aren't aimed at the same stop/hole on the mask ... they are aimed at exact same area of phosphors. Ie, without the mask ...
I see 'perfect' convergence as each electron beam aimed at the exact same spot/area of the phosphor area.

The mask makes sure each beam hits a correctly colored phosphor. However, if the mask wasn't there ... and you froze the electron beams at a single point in time ... you'd get a nice perfect O on the screen (at the phosphor area).

I'm gonna have to disagree with you (for the first time :)). The electron beams converge on the mask and then diverge after the mask.

Yes, they do not target holes in the mask but they also do not target areas on the screen. ALL that is necessary is that the three beams converge on the mask (regardless of the area on the mask).

Take this scenario:

The guns either scan 1000 lines or 10 lines. In both cases the three beams converge onto the mask to allow for proper color selection.

Now you can put whatever definiton mask in front of those guns (100 holes, or 10 million holes) and as long as a triad is in front of each hole and the angle dependance is maintained you will get proper color selection.

But the 10 million hole mask will more closely reproduce the INTENDED picture for both the 1000 line guns and the 10 line guns!!!!!!!

edit: 10 million holes might bring the holes too close together and angle dependance would break down and there would be a loss of color selection. This could be a limiting factor in the production of hi-res CRTs

dt_dc

11-23-04, 03:28 PM

Ok ... so this is my picture of how the mask / beams / phosphors work ... and what perfect convergence would be.
http://members.cox.net/dt_dc/convergeFinal.GIF
Black = Shadow Mask
3 Beams ... each hitting their respective color phosphor
I extended the edge-lines to show where each beam would hit w/o the mask ... at the same place ... w/o the shadow mask. Obviously, in actuality, the beams are blocked and only the 'solid' area gets through.

This is the xrox and ss image correct?
http://www.avsforum.com/avs-vb/attachment.php?s=&postid=4696955&fullpage=1

dt_dc

11-23-04, 03:35 PM

Originally posted by xrox
The guns either scan 1000 lines or 10 lines. In both cases the three beams converge onto the mask to allow for proper color selection.

Now you can put whatever definiton mask in front of those guns (100 holes, or 10 million holes) and as long as a triad is in front of each hole and the angle dependance is maintained you will get proper color selection.

But the 10 million hole mask will more closely reproduce the INTENDED picture for both the 1000 line guns and the 10 line guns!!!!!!!How is my picture above not performing color seperation?

And I agree ... the more holes ... (and corresponding phosphor dots) ... the more accurate the picture ... whatever else is going on.

In what way is my picture not allowing that?

You do, of course, run in to problems with light output / etc with too many holes ...

xrox

11-23-04, 03:38 PM

dt_dc

11-23-04, 03:54 PM

Originally posted by xrox
In my mind this would not work because you could get poor color purity as you scan along the mask. One color would shut off before the other two.

You have to converge on the mask so when a hole is penetrated by the coverged beams, all three colors enter no matter what! What do you mean by 'shut off'? Do you mean phosphor on/off? That .001 seconds between when one gun hits the screen and the other is NOT going to be noticed by the eye. It can't see the difference between when the top left triad on the screen is hit vs. the bottom right ... keep in mind phosphor lag ...

Or do you mean 'shut off' as in accuracy of the picture (ie, not all the red phosphor is lit)?
Go through the some cases using this picture:
http://members.cox.net/dt_dc/FullCRT.GIF
You actually get a MUCH more accurate picture ...

I'll be doing that in a bit.

xrox

11-23-04, 04:01 PM

montreal

11-23-04, 04:04 PM

Originally posted by dt_dc
Ok ... so this is my picture of how the mask / beams / phosphors work ... and what perfect convergence would be.
http://members.cox.net/dt_dc/convergeFinal.GIF
Black = Shadow Mask
3 Beams ... each hitting their respective color phosphor
I extended the edge-lines to show where each beam would hit w/o the mask ... at the same place ... w/o the shadow mask. Obviously, in actuality, the beams are blocked and only the 'solid' area gets through.

Also remember that all three beams are moved in tandem by the same deflection plates/coils, so it is impossible to force all three to be perfectly converged throughout the screen.

Often a horizontal white line drawn at the center will be slightly bowed at each end and there you will see how the white line splits into three colored lines. It is impossible to get all three beams to focus simultaneously on their respective phosphors within a triad because there is not an independent deflection circuit for each beam. All three beams are subject to the same electromagnetic and electrostatic forces of deflection and because the guns are minutely positioned apart, the beams they emit do not bend identically.

Also XROX, in your very accurate diagram (IMO), if you turn off the BLUE and GREEN color guns and take away the mask, then the remaining RED color gun will strike not only the red phosphors, but whatever other different color phosphors that happen to lie in its (not always) perfect horizontal path. This is where SUBYSOUTH and I began to disagree and since he is sticking to his guns, I don't want to preach to the unconvertible any more.

xrox

11-23-04, 04:12 PM

Originally posted by montreal
if you turn off the BLUE and GREEN color guns and take away the mask, then the remaining RED color gun will strike not only the red phosphors, but whatever other different color phosphors that happen to lie in its (not always) perfect horizontal path. This is where SUBYSOUTH and I began to disagree and since he is sticking to his guns, I don't want to preach to the unconvertible any more.

sticking to his guns.........:) good one.

The question arises, is there a limit in the number of triads due to angles/color selection (as well as brightness)?

Cheers

subysouth

11-23-04, 04:43 PM

I dont really see a lot of disagreement currently on how the screen is addresed. We have resolved what the dot mask lines are comprised of, which was a big deal. We have resolved that the intherent angles built into the guns relative to the holes in the mask dictate which phosphor triad is hit.

The bigger questions to me a how many holes at one time is the gun trying to hit. The guy at KDS says one. Hitting more than one at a time intentionally essentially halves the resolution or worse. I think the set tries to hit one but often due to low build quality hits more than one unintentionally. Then rescans a more saturated correct image over it on the next pass.

I also still have no reason to believe that beam spot re-sizes for varying scan rates.

For the record this generally is much closer IMO to what is happening(posted before):

http://www.infocellar.com/hardware/monitor/shadowmask-beams.gif

Its much closer to correct scale on the angles of the guns to each other and the resultant beams are correct IMO. Just make those electron beams hitting the back of the mask about 2.5 times larger in diameter(enough to partially overlap 2 scans lines if vertically misaligned) and you essentially have the average dot mask CRT. Other than that I believe the INTENDED function of the set is identical to this pic. Addressing, one triad sequentially at a time. There are lots of design compromises in mass-produced sets, but the intent is as above.

BTW as near as I can tell that image was taken from a PHD thesis on display techs by an OSU student named Bender. I believe it to be very accurate.

ss

montreal

11-23-04, 04:49 PM

Originally posted by xrox
The question arises, is there a limit in the number of triads due to angles/color selection (as well as brightness)?

In theory, by shrinking everything proportionally, you could add more holes and have each hole and each phosphor dot have a smaller diameter and at the same time have the total surface area of the mask minus the total surface area of the holes in the mask remain constant. This should allow the same number of electrons to pass through the holes to the phosphor dots as before. The overall picture would be less grainier, but not necessarily display more detail, because detail depends primarily on the high frequency content of the signal and the sharpness of the focus.

In practical terms, there is a limit to how thin you can make the spaces of metal between the holes because this metal is fragile like the screen on a electric shaver and constantly under bombardment by atomic particles having some mass (electrons). The electrons coming out of the guns of your TV are driven by a harder voltage than your computer monitor because the anode is farther away.

Also, how do you keep shrinking the diameter of the phosphor dots? The fascinating article above about the construction of the CRT describes how white light passes through the permanent mask to photographically expose the different color phosphor coatings on the glass. No matter how minutely different each mask is from another, the phosphor coating of the CRT where it will reside is customized for it.

We are able to expose millions of transistors per square inch on silicon wafers using light, so it is not a big leap of faith to imagine that we could make phosphor dots to have a diameter of say 0.03 mm instead of the usual 0.15. If we use laser light to expose, then we might actually get a really small phosphor dot, but I still think it is the mechanical limits of the mask that will hold us back. We can only etch the holes in the metal so small. If we could get each gun to be independently aim-able, then we might be able to do away with the mask.

subysouth

11-23-04, 04:53 PM

Originally posted by montreal
Also remember that all three beams are moved in tandem by the same deflection plates/coils, so it is impossible to force all three to be perfectly converged throughout the screen.

Often a horizontal white line drawn at the center will be slightly bowed at each end and there you will see how the white line splits into three colored lines. It is impossible to get all three beams to focus simultaneously on their respective phosphors within a triad because there is not an independent deflection circuit for each beam. All three beams are subject to the same electromagnetic and electrostatic forces of deflection and because the guns are minutely positioned apart, the beams they emit do not bend identically.

Also XROX, in your very accurate diagram (IMO), if you turn off the BLUE and GREEN color guns and take away the mask, then the remaining RED color gun will strike not only the red phosphors, but whatever other different color phosphors that happen to lie in its (not always) perfect horizontal path. This is where SUBYSOUTH and I began to disagree and since he is sticking to his guns, I don't want to preach to the unconvertible any more.

Where am I sticking to my guns incorrectly?

ss

subysouth

11-23-04, 05:01 PM

Originally posted by montreal
In theory, by shrinking everything proportionally, you could add more holes and have each hole and each phosphor dot have a smaller diameter and at the same time have the total surface area of the mask minus the total surface area of the holes in the mask remain constant. This should allow the same number of electrons to pass through the holes to the phosphor dots as before. The overall picture would be less grainier, but not necessarily display more detail, because detail depends primarily on the high frequency content of the signal and the sharpness of the focus.

In practical terms, there is a limit to how thin you can make the spaces of metal between the holes because this metal is fragile like the screen on a electric shaver and constantly under bombardment by atomic particles having some mass (electrons). The electrons coming out of the guns of your TV are driven by a harder voltage than your computer monitor because the anode is farther away.

Also, how do you keep shrinking the diameter of the phosphor dots? The fascinating article above about the construction of the CRT describes how white light passes through the permanent mask to photographically expose the different color phosphor coatings on the glass. No matter how minutely different each mask is from another, the phosphor coating of the CRT where it will reside is customized for it.

We are able to expose millions of transistors per square inch on silicon wafers using light, so it is not a big leap of faith to imagine that we could make phosphor dots to have a diameter of say 0.03 mm instead of the usual 0.15. If we use laser light to expose, then we might actually get a really small phosphor dot, but I still think it is the mechanical limits of the mask that will hold us back. We can only etch the holes in the metal so small. If we could get each gun to be independently aim-able, then we might be able to do away with the mask.

Not only difficult to do but likely pointless in most cases due to viewing distance too. To appreciate an estimated .13mm dot pitch, you literally would need to be on top of the screen.

ss

xrox

11-23-04, 05:04 PM

montreal

11-23-04, 05:06 PM

Originally posted by subysouth
IThe bigger questions to me a how many holes at one time is the gun trying to hit. The guy at KDS says one. Hitting more than one at a time intentionally essentially halves the resolution or worse. I think the set tries to hit one but often due to low build quality hits more than one unintentionally. Then rescans a more saturated correct image over it on the next pass.

I also still have no reason to believe that beam spot re-sizes for varying scan rates.

For the record this generally is much closer IMO to what is happening(posted before):

http://www.infocellar.com/hardware/monitor/shadowmask-beams.gif

Its much closer to correct scale on the angles of the guns to each other and the resultant beams are correct IMO. Just make those electron beams hitting the back of the mask about 2.5 times larger in diameter(enough to partially overlap 2 scans lines if vertically misaligned) and you essentially have the average dot mask CRT. Other than that I believe the INTENDED function of the set is identical to this pic. Addressing, one triad sequentially at a time. There are lots of design compromises in mass-produced sets, but the intent is as above.

BTW as near as I can tell that image was taken from a PHD thesis on display techs by an OSU student named Bender. I believe it to be very accurate.

ss

I agree with you, that we are ideally trying to do exactly as the diagram suggests. And it does not matter if one beam arrives at the hole a few microseconds before the other two. But I have worked with CRTs enough over the years to believe that the beam diameters are slightly larger than the hole diameter and that there is enough mis-convergence that even if the beams were sharper, they would never pass through all half million holes in unison.

I also agree with you that the beam is probably not resized for various scan rates, at least not on TV sets. I don't know if the focus can be changed under electronic control, but given that the SONY does 480 and 540 line spacing, there is not enough difference between the two vertical line pitches to require an adjustment to the beam spot size.

Glad to see that SUBYSOUTH and I agree more and more on some basic ideas.

subysouth

11-23-04, 05:09 PM

Originally posted by montreal
I agree with you, that we are ideally trying to do exactly as the diagram suggests. And it does not matter if one beam arrives at the hole a few microseconds before the other two. But I have worked with CRTs enough over the years to believe that the beam diameters are slightly larger than the hole diameter and that there is enough mis-convergence that even if the beams were sharper, they would never pass through all half million holes in unison.

I also agree with you that the beam is probably not resized for various scan rates, at least on TV sets. I don't know if the focus can be changed under electronic control, but given that the SONY does 480 and 540 line spacing, there is not enough difference between the two vertical line pitches to require an adjustment to the beam spot size.

Glad to see that SUBYSOUTH and I agree more and more on some basic ideas.

Cool. I also completely agree with your above post on screen area v mask area.

What am I unconvertible on?

ss

Edit and back to the Sony in question for a sec, now that we have a "working" description of dot mask and shadow mask sets and the fact that dot mask sets partially interlace their vertical lines(angular relation of seperate triads) and aperature grille sets in theory do not(vertical orientation of triads,) are we seeing my inherent skepticism at doing both 480p and 1080i without obvious screen real estate loss? The better Sony discretely displays the vertical resolution the worse the differences in these line counts will be. Still very skeptical of 1080i on the Sonys(or any 34" set.)

montreal

11-23-04, 05:24 PM

Just for the record, because the mask is so close to the front screen, the mask hole diameter is very similar to that of the phosphor dot diameter. A close up view of your screen (monitor) will show you that the color dots are crammed one on top of the other with very little space between dots. Likewise there is not a whole lot of metal between holes, but at least the total area of all metal bridges must be 200% of the total area of all holes. (IE: holes make up exactly 1/3 of the total mask area.)

So while the various diagrams display very well the triangular relationships, I hope you all appreciate that the sizing of all these holes and spots is way out of scale. Knowing this helps you to better discuss the subjects of bleeding and overscaning, and ultimately resolution.

See you tomorrow.

montreal

11-23-04, 05:45 PM

Originally posted by subysouth
are we seeing my inherent skepticism at doing both 480p and 1080i without obvious screen real estate loss? The better Sony discretely displays the vertical resolution the worse the differences in these line counts will be. Still very skeptical of 1080i on the Sonys(or any 34" set.)

I agree that if the Sony is to be optimized for 540 lines per frame, then it should do a vertical compression by about 11% so that the vertical distance between scan lines remains constant for 480p. To do so would result in black bars above and below the raster. To not do so means that we now have potentially a gap between the lines at 480 lines per frame. I suspect, that the beam spot diameter is larger than the ideal that both you and I would hope for and it is that slight over scanning that makes any weakness between the lines at 480 disappear at the expense of slightly blurring the 540 lines together. For dot masks, the trade offs would be slightly different, but I don't know of any TV sets with dot masks and two native scan rates. If you were to get the vertical pitch of the dot masks to match perfectly the vertical distances between scan lines, then you might get a moire pattern at some parts of the screen as the beams fail to move perfectly.

As some musical instruments have to be tuned slightly off perfect pitch to sound right, I suspect that the PANNY with its 611 vertical holes had that number chosen to avoid having a 100% hit or miss situation.

subysouth

11-23-04, 10:38 PM

Originally posted by montreal
I agree that if the Sony is to be optimized for 540 lines per frame, then it should do a vertical compression by about 11% so that the vertical distance between scan lines remains constant for 480p. To do so would result in black bars above and below the raster. To not do so means that we now have potentially a gap between the lines at 480 lines per frame. I suspect, that the beam spot diameter is larger than the ideal that both you and I would hope for and it is that slight over scanning that makes any weakness between the lines at 480 disappear at the expense of slightly blurring the 540 lines together. For dot masks, the trade offs would be slightly different, but I don't know of any TV sets with dot masks and two native scan rates. If you were to get the vertical pitch of the dot masks to match perfectly the vertical distances between scan lines, then you might get a moire pattern at some parts of the screen as the beams fail to move perfectly.

As some musical instruments have to be tuned slightly off perfect pitch to sound right, I suspect that the PANNY with its 611 vertical holes had that number chosen to avoid having a 100% hit or miss situation.

But what of 1080i? I have no problem accepting good performance on 480 and 540p, its that leap to 1080i I am most concerned with(not it doing it, but whether its doing it.) And if its not doing it, why scan it that way? It would be better scanned progressively close to its actual res.

The old analog sets that were being asked to do 480i, actually have about 480 seperate available vertical phosphors triads(again I have actually counted them on my Panny-came out to 485.) So if we dont have the 1080 seperate vertical triads in a the new dot mask sets, we've had paradigm shift in resolution of actual versus theoretical. The Sony is harder to pin dwon because of the continuos vertical stripe, but if it is doing 480p somethings giving somewhere. Or there is something else afoot.

I think I would be more comfortable with the Sony's res if they claimed and ran all of it to 1080i. Its doing the widely spread resolutions I dont think is good. Too many compromises.

ss

dt_dc

11-24-04, 03:05 AM

Originally posted by xrox
Look at your picture above. The three beam centers do not intersect at the mask. So when scanning takes place (downwards) the red beam will be blocked by the mask while the other two enter the hole.

Look at my picture of the three beams. The centers intersect at the mask. Therefore during scanning all three beams will enter a hole NO MATTER WHAT. This is actually an AWSOME point. However, it works in the opposite way. Converging on the screen is the only way to guarauntee that every beam will hit a phosphor on the next scan line.

So according to this:
http://members.cox.net/dt_dc/convergeFinal.GIF

Let's look at what happens when we go from line to line:

I'm going to make it a curved screen ... because the angles are much easier to figure out (just like in real CRTs). We also have to move the electron guns closer together. The math still all works out when the are exagerated like above, but it gets very hard to see.

Here's line 1:
http://members.cox.net/dt_dc/ConvOne.gif

And Here's line 2:
http://members.cox.net/dt_dc/ConvTwo.gif

Here's both together:
http://members.cox.net/dt_dc/ConvBoth.gif

Ok, I gotta admit it's easier without the colors ... just black and white with lables. I'll post that if need be.

However, doing the above guarauntees that everything will work all around the screen. Every gun ... is hitting corectly colored phosphor ... as it moves anywhere around the screen ... and every gun is totally prevented from hitting the wrong colored phosphor.

Converging at the mask starts running in to problems as we move around the screen.

xrox

11-24-04, 10:15 AM

Originally posted by dt_dc
This is actually an AWSOME point. However, it works in the opposite way. Converging on the screen is the only way to guarauntee that every beam will hit a phosphor on the next scan line.

So according to this:
http://members.cox.net/dt_dc/convergeFinal.GIF

Let's look at what happens when we go from line to line:

I'm going to make it a curved screen ... because the angles are much easier to figure out (just like in real CRTs). We also have to move the electron guns closer together. The math still all works out when the are exagerated like above, but it gets very hard to see.

Here's line 1:
http://members.cox.net/dt_dc/ConvOne.gif

And Here's line 2:
http://members.cox.net/dt_dc/ConvTwo.gif

Here's both together:
http://members.cox.net/dt_dc/ConvBoth.gif

Ok, I gotta admit it's easier without the colors ... just black and white with lables. I'll post that if need be.

However, doing the above guarauntees that everything will work all around the screen. Every gun ... is hitting corectly colored phosphor ... as it moves anywhere around the screen ... and every gun is totally prevented from hitting the wrong colored phosphor.

Converging at the mask starts running in to problems as we move around the screen.

I'm not going to say you are wrong because I really don't know. But my interpretation just makes more sense to me right now.

What you are describing is what a projector needs to do (convergence on the screen). All the RGB beams must overlap for "additive color".

A direct view CRT must seperate the RGB components. Therefore the mask acts like the projectors screen and since the phosphors are placed beyond the mask it allows for divergence and color seperation.

http://graphics.tomshardware.com/display/20020319/crt-02.html

Your graphic shows a lack of convergence and hence poor color purity during scanning.

IMO of course :)