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OLED TVs: Technology Advancements Thread - Page 212

post #6331 of 9427
Quote:
Originally Posted by tgm1024 View Post

I'd like GM to confirm that the RGB stack image is *indeed* from LG themselves.  Because frankly, this is getting confusing.  Unless they're regarding the "yellow" emitter as "red/green" like they did in the image that ynotgoal supplied.

That image is from LG, but the image alone says nothing since you are looking at the color filter part of the LG, which of course contains R G and B color filters.

As for whether the sandwich contains three colors, I was told it was, ynotgoal seems to know otherwise (though many of the linked documents he's pulled are so old and irrelevant, I wonder what his sources are).

I fail to see why it matters. They use a stack, they make white light, they filter the light back to R G and B and unfiltered white.
post #6332 of 9427
Quote:
Originally Posted by rogo View Post

Quote:
Originally Posted by tgm1024 View Post

I'd like GM to confirm that the RGB stack image is *indeed* from LG themselves.  Because frankly, this is getting confusing.  Unless they're regarding the "yellow" emitter as "red/green" like they did in the image that ynotgoal supplied.

That image is from LG, but the image alone says nothing since you are looking at the color filter part of the LG, which of course contains R G and B color filters.

 

No, this image shows the RGB underpinnings as discrete layers.

 

 

 

Quote:
Originally Posted by rogo View Post

I fail to see why it matters. They use a stack, they make white light, they filter the light back to R G and B and unfiltered white.


It matters because of what might happen when the blue fades.  For a while there it really looked like a blue OLED with a yellow phosphor (the blue and yellow "emitters").  This has a dramatically different effect as blue fades than it would if the 3 colors were just blasting out independently.

 

To a large extent, none of any of what we talk about matters, but the denizens here are deeply interested in video technology.

post #6333 of 9427
The OLED stack is definitely made up of a yellow emitter layer and a blue emitter layer. The source of that info is the supplier of the materials, Universal Display.

The yellow emitter is basically the green emitter with a small amount of red emitter added to the layer.
post #6334 of 9427
Quote:
Originally Posted by slacker711 View Post

The OLED stack is definitely made up of a yellow emitter layer and a blue emitter layer. The source of that info is the supplier of the materials, Universal Display.

The yellow emitter is basically the green emitter with a small amount of red emitter added to the layer.

 

As the Thin Film Luminescent itself, or as a phosphor activated by the blue?

post #6335 of 9427
Quote:
Originally Posted by tgm1024 View Post

Quote:
Originally Posted by slacker711 View Post

The OLED stack is definitely made up of a yellow emitter layer and a blue emitter layer. The source of that info is the supplier of the materials, Universal Display.

The yellow emitter is basically the green emitter with a small amount of red emitter added to the layer.

 

As the Thin Film Luminescent itself, or as a phosphorescent activated by the blue?

post #6336 of 9427
Quote:
Originally Posted by tgm1024 View Post

As the Thin Film Luminescent itself, or as a phosphor activated by the blue?

Dont think of this like a LED with a yellow phosphor on top of a blue LED.

The yellow material itself emits light when a current is applied (as does the blue). I hadnt heard the term Thin Film Luminescent but I think that applies.

The term phosphorescent refers to the type of OLED material. The first materials discovered were fluorescent materials (by Kodak). These only emitted 25% of the possible light and thus use a considerable amount of power. Universal Display later discovered phosphorescent materials which allowed for a 100% internal quantum efficiency.

The yellow material in the LG television is phosphorescent (as is the red/green in Samsung's TV's). The blue in both is fluorescent since they have yet to make a phosphorescent blue with a decent lifetime.
post #6337 of 9427
Quote:
Originally Posted by tgm1024 View Post

No, this image shows the RGB underpinnings as discrete layers.







It matters because of what might happen when the blue fades.  For a while there it really looked like a blue OLED with a yellow phosphor (the blue and yellow "emitters").  This has a dramatically different effect as blue fades than it would if the 3 colors were just blasting out independently.

To a large extent, none of any of what we talk about matters, but the denizens here are deeply interested in video technology.

Quote:
Originally Posted by ynotgoal View Post



Just to add to Slacker's post. Look at the "white EL" in the graph. The blue emitter produces the steep left peak in the blue spectrum but almost nothing in the red and green spectrum. The yellow emitter produces the rest with the two peaks in the red and green spectrum. This is why LG and most everyone will show it as red, green and blue emitter even though it is physically only two material layers.
post #6338 of 9427
Just to knock this out of the box, what about this TLED info? Will TLED "assimilate" OLED if it works out? Three to four times the efficiency of while light produced, run thru "LCD" filters might make this a whole new ball game.
post #6339 of 9427
Quote:
Originally Posted by tgm1024 View Post

No, this image shows the RGB underpinnings as discrete layers.

Sure enough, it does.
Quote:
It matters because of what might happen when the blue fades.  For a while there it really looked like a blue OLED with a yellow phosphor (the blue and yellow "emitters").  This has a dramatically different effect as blue fades than it would if the 3 colors were just blasting out independently.

It simply does not matter whether the green and red are together in yellow or separate with respect to the blue. The blue is the weak link. I don't know why you think it matters if there are 3 or 2 layers, but it doesn't.
Quote:
Originally Posted by slacker711 View Post

The OLED stack is definitely made up of a yellow emitter layer and a blue emitter layer. The source of that info is the supplier of the materials, Universal Display.

The yellow emitter is basically the green emitter with a small amount of red emitter added to the layer.

Thanks Slacker. In my mind, that's confirmation (given you are the source, with a reference cited.
Quote:
Originally Posted by slacker711 View Post

Dont think of this like a LED with a yellow phosphor on top of a blue LED.

The yellow material itself emits light when a current is applied (as does the blue). I hadnt heard the term Thin Film Luminescent but I think that applies.

The term phosphorescent refers to the type of OLED material. The first materials discovered were fluorescent materials (by Kodak). These only emitted 25% of the possible light and thus use a considerable amount of power. Universal Display later discovered phosphorescent materials which allowed for a 100% internal quantum efficiency.

The yellow material in the LG television is phosphorescent (as is the red/green in Samsung's TV's). The blue in both is fluorescent since they have yet to make a phosphorescent blue with a decent lifetime.

Honestly, the fluorescent blue doesn't have a decent lifetime either. It has a lifetime that allows them to contemplate making TVs, but it's hardly impressive. The good news is a lot of people will probably never experience problems. The bad news is there needs to be a 50,000+ hour material, ideally phosphorescent, in the long run. A dozen years into the OLED era, no such thing has been developed.
Quote:
Originally Posted by ynotgoal View Post


Just to add to Slacker's post. Look at the "white EL" in the graph. The blue emitter produces the steep left peak in the blue spectrum but almost nothing in the red and green spectrum. The yellow emitter produces the rest with the two peaks in the red and green spectrum. This is why LG and most everyone will show it as red, green and blue emitter even though it is physically only two material layers.

Reasonable.
post #6340 of 9427
So any other theories (besides to attract attention) as to why both companies released curved models ahead of the flat ones? Could there be a manufacturing advantage that improves yield on a curved surface? Maybe it allows them to rotate the panel relative to some equipment thanks to the constant distance of the surface.
Edited by Wizziwig - 7/23/13 at 11:26pm
post #6341 of 9427
Pure marketing strategy.
post #6342 of 9427
Quote:
Originally Posted by rogo View Post

Quote:
It matters because of what might happen when the blue fades.  For a while there it really looked like a blue OLED with a yellow phosphor (the blue and yellow "emitters").  This has a dramatically different effect as blue fades than it would if the 3 colors were just blasting out independently.

It simply does not matter whether the green and red are together in yellow or separate with respect to the blue. The blue is the weak link. I don't know why you think it matters if there are 3 or 2 layers, but it doesn't.

 

The point is mooted now, because the yellow emitter has been established as a non-phosphor (phosphors can also be considered emitters), but if you read what I said carefully, you'll see that if it was indeed a yellow phosphor then as blue dies, the yellow "dies" (emits less).  Not strictly 1:1 because there's a problem with the efficiency of the stokes shift, but very close for all practical purposes and certainly closer than two OLED's.  A single blue oled + Y phoshor would mean that as the blue dies down the effect would be a shift downward maintaining a clean gray component (not chromatically "tinged").  So an aging blue would be countered by simply making driving it harder over time (assuming they were kept at a lesser amount earlier).

 

Now that we have confirmation (I'll certainly take it as such: slacker & ynotgoal seem solid folks to me) that the yellow emitter is in fact an OLED, then we now do see that there's a problem with color shifting over time.

post #6343 of 9427
Quote:
Originally Posted by Wizziwig View Post

So any other theories (besides to attract attention) as to why both companies released curved models ahead of the flat ones? Could there be a manufacturing advantage that improves yield on a curved surface? Maybe it allows them to rotate the panel relative to some equipment thanks to the constant distance of the surface.

 

With all new technologies, there is a perceived need to establish yourself as either:

  • the pioneer (no pun), or
  • at least not falling behind

 

I believe when you put a marketing hat on, you need to think more like a mob does than any one individual.  As individuals we recognize things as stupid.  As an aggregate force though, we are all swayed by silly impressions.

post #6344 of 9427
Quote:
Originally Posted by tgm1024 View Post

Not for $15,000 displays they're not.  Besides, regardless, I'm concerned about a big distinction here that I'm not sure many are considering.  A pretty bad "what if".
Do you forget that this is what plasma was like when it was new?
Quote:
Originally Posted by tgm1024 View Post

On a plasma set, if you display a big bright "X" in the middle of a black screen and hold it there for a long time, you'll eventually get some IR....perhaps eventual burn. If, however, you display for only a second at a time, interspersed with 3 seconds of random patterns, then the IR doesn't show up.

HOWEVER, if the burn in on an OLED comes from age, then the only thing that those 3 seconds will do will be to make it take 4x longer for the burn in to occur.  There is likely no pixel-orbiter or cycling pattern "repair" effect to come to the rescue.
Burn-in is an accumulative process with Plasma displays as well, and in my experience it's not that difficult to burn them if you are primarily using them for playing games, or have essentially permanent uneven wear from watching 2.37:1 films all the time.
post #6345 of 9427
^^^

my first plasma was a Pioneer 50 inch purchased new in 1999: it was $14,950.00: and it never had burn in
post #6346 of 9427
Quote:
Originally Posted by markrubin View Post

^^^

my first plasma was a Pioneer 50 inch purchased new in 1999: it was $14,950.00: and it never had burn in

I had two of those.
I gave one to my father and it had burn n since he watches mostly news.
I am not sure any what this proves.

It appears that these panels will have uneven wear for the color primaries.
That will produce burn in.
I have also seen Samsung phones with severe burnin on the display units.

- Rich
post #6347 of 9427
Quote:
Quote:
Originally Posted by ynotgoal View Post


Just to add to Slacker's post. Look at the "white EL" in the graph. The blue emitter produces the steep left peak in the blue spectrum but almost nothing in the red and green spectrum. The yellow emitter produces the rest with the two peaks in the red and green spectrum. This is why LG and most everyone will show it as red, green and blue emitter even though it is physically only two material layers.

 

WHOA, WAIT A MINUTE.  That graph cannot be showing the emitters in the stack, they're showing the resulting subpixels: white, red, green, blue.  If they were showing the emitters, they'd be showing only 3 lines: the blue, the yellow, and the "resulting" addition of the two as perceived by our eyes---the white.

 

It's true that the yellow emitter is producing the non-blue regions, (that is the whole point and nothing new----it's how I started this whole dichromatic discussion in the first place), but that's not what that graph is technically showing.....how could it?

post #6348 of 9427
Quote:
Originally Posted by Chronoptimist View Post

Quote:
Originally Posted by tgm1024 View Post

Not for $15,000 displays they're not.  Besides, regardless, I'm concerned about a big distinction here that I'm not sure many are considering.  A pretty bad "what if".
Do you forget that this is what plasma was like when it was new?

 

Of course I don't.  Those were bad buying decisions back then too.  Will OLED grow out of it?  Sure.  But how long has an over-exaggerated worry about plasma hung around plasma's neck?  A long time.  I would argue that the early releasing of plasma back then (while not technically a bad idea, nor even a stoppable one) is a great analogy to how troubling problems can be a long term disaster to a technology---whether that problem ends up being mostly fixed or not.

 

 

Quote:
Quote:
Originally Posted by tgm1024 View Post

On a plasma set, if you display a big bright "X" in the middle of a black screen and hold it there for a long time, you'll eventually get some IR....perhaps eventual burn. If, however, you display for only a second at a time, interspersed with 3 seconds of random patterns, then the IR doesn't show up.

HOWEVER, if the burn in on an OLED comes from age, then the only thing that those 3 seconds will do will be to make it take 4x longer for the burn in to occur.  There is likely no pixel-orbiter or cycling pattern "repair" effect to come to the rescue.
Burn-in is an accumulative process with Plasma displays as well, and in my experience it's not that difficult to burn them if you are primarily using them for playing games, or have essentially permanent uneven wear from watching 2.37:1 films all the time.

 

Not exactly the same way though.  Plasma's burn most horribly when an image is held static and not broken up by interspersed pseudo random images.  OLED's I'm guessing just burn based upon age, regardless of how long a subpixel was held at a certain level consecutively.

post #6349 of 9427
Quote:
Originally Posted by tgm1024 View Post

WHOA, WAIT A MINUTE.  That graph cannot be showing the emitters in the stack, they're showing the resulting subpixels: white, red, green, blue.  If they were showing the emitters, they'd be showing only 3 lines: the blue, the yellow, and the "resulting" addition of the two as perceived by our eyes---the white.

It's true that the yellow emitter is producing the non-blue regions, (that is the whole point and nothing new----it's how I started this whole dichromatic discussion in the first place), but that's not what that graph is technically showing.....how could it?

White EL is the combined output of the emitters. Red, green and blue CF are color filters. The point, as you surmised, is blue dying out doesn't affect the output in the red and green. Note that JWhip indicated the burn in area was affected the same in a green screen as it was in a blue screen.
post #6350 of 9427
Quote:
Originally Posted by ynotgoal View Post

Quote:
Originally Posted by tgm1024 View Post

WHOA, WAIT A MINUTE.  That graph cannot be showing the emitters in the stack, they're showing the resulting subpixels: white, red, green, blue.  If they were showing the emitters, they'd be showing only 3 lines: the blue, the yellow, and the "resulting" addition of the two as perceived by our eyes---the white.

It's true that the yellow emitter is producing the non-blue regions, (that is the whole point and nothing new----it's how I started this whole dichromatic discussion in the first place), but that's not what that graph is technically showing.....how could it?

White EL is the combined output of the emitters. Red, green and blue CF are color filters. The point, as you surmised, is blue dying out doesn't affect the output in the red and green. Note that JWhip indicated the burn in area was affected the same in a green screen as it was in a blue screen.

 

Yeah, a guess of mine and others is that a skewed white filtered red is still pretty close to a non-skewed white filtered red.  Samsung doesn't have this, so we'll have to see what THEY look like.

post #6351 of 9427
Quote:
Originally Posted by tgm1024 View Post

Yeah, a guess of mine and others is that a skewed white filtered red is still pretty close to a non-skewed white filtered red.  Samsung doesn't have this, so we'll have to see what THEY look like.

One of the benefits of LG's approach is supposed to be the stability of the white light.

Here is a paper from Kodak talking about a white OLED with yellow and blue emitters. There are other papers that express a similar sentiment.

http://lib.semi.ac.cn:8080/tsh/dzzy/wsqk/SPIE/vol5214/5214-233.pdf
Quote:
The spectrum of these white devices is largely insensitive to drive current density and operational aging:

Now I will admit that this is a case where a little knowledge may be dangerous. The materials in these papers are going to be different and I cant say for certain what structure LG has used, but generally my understanding is that color stability is supposed to be a strength of white OLED's.
post #6352 of 9427
Quote:
Originally Posted by slacker711 View Post

Quote:
Originally Posted by tgm1024 View Post

Yeah, a guess of mine and others is that a skewed white filtered red is still pretty close to a non-skewed white filtered red.  Samsung doesn't have this, so we'll have to see what THEY look like.

One of the benefits of LG's approach is supposed to be the stability of the white light.

Here is a paper from Kodak talking about a white OLED with yellow and blue emitters. There are other papers that express a similar sentiment.

http://lib.semi.ac.cn:8080/tsh/dzzy/wsqk/SPIE/vol5214/5214-233.pdf
Quote:
The spectrum of these white devices is largely insensitive to drive current density and operational aging:

Now I will admit that this is a case where a little knowledge may be dangerous. The materials in these papers are going to be different and I cant say for certain what structure LG has used, but generally my understanding is that color stability is supposed to be a strength of white OLED's.

 

This is going to take some sorting through to get right.

post #6353 of 9427
There are curved screen OLED TVs from LG and Samsung appearing in the US. They are not yet available here and I would be interested in the following.

I gather the LG cannot be wall-mounted. Is this also true for the Samsung?

Does the Samsung come with the frame shown on some photos? Or can it be removed?

I also wondered about the curved screen, and whether there is any distortion when viewing it other than from straight ahead.

eek.gif
post #6354 of 9427
The OLED layers are deposited and excited separately (whether it's a yellow + blue or a red, green and blue). The idea that there is some magic color stability of the LG even though the blue will age faster is false. The Kodak paper is either (a) complete fiction or (b) based on having a yellow OLED that is equally terrible to the blue in terms of lifetime, which simply isn't the case.
post #6355 of 9427
Quote:
Originally Posted by mypretty1 View Post

There are curved screen OLED TVs from LG and Samsung appearing in the US. They are not yet available here and I would be interested in the following.

I gather the LG cannot be wall-mounted. Is this also true for the Samsung?

Does the Samsung come with the frame shown on some photos? Or can it be removed?

I also wondered about the curved screen, and whether there is any distortion when viewing it other than from straight ahead.

eek.gif

Regarding distortion, maybe this old video will help:
post #6356 of 9427
Quote:
Originally Posted by rogo View Post

The OLED layers are deposited and excited separately (whether it's a yellow + blue or a red, green and blue). The idea that there is some magic color stability of the LG even though the blue will age faster is false. The Kodak paper is either (a) complete fiction or (b) based on having a yellow OLED that is equally terrible to the blue in terms of lifetime, which simply isn't the case.

 

Again, it's mooted already, but this is precisely why I was trying to relentlessly get a sense as to what that yellow layer truly is, and if it's affected by the blue underneath in any way at all that a YAG-yellow (or similar) phosphor would be in order to better auto-correct the white naturally.

 

By the way, there's no way in hell that a Kodak paper is complete fiction.  It's far more likely that we're misreading something.

 

The problem with white papers written by scientists is they *always* write to the wrong target.  Their descriptions always are written to other scientists who would be making the same fundamental assumptions they do as to the meanings, and it throws everyone else for a loop.

post #6357 of 9427
Quote:
Originally Posted by markrubin View Post

^^^

my first plasma was a Pioneer 50 inch purchased new in 1999: it was $14,950.00: and it never had burn in

The difference is plasma had to overcome economies of scale to reduce price, whereas OLED has to overcome technical problems of 90% failure rates. And to that, pressure by 4K marketing and 2K OLED for the home theater market is all but dead. We are back to waiting for the holy grail again. Namely, someone to find a better and cheaper way to produce large 4K OLED panels.
post #6358 of 9427
So I guess we all got lucky that some idiot at Harrod's burned-in both of their OLEDs. Without such abuse we may not have known the true burn-in potential on the LG for many months (or never) given the low sales and internet posts. What are the chances we'll get that lucky again on the Samsung?

The largest Samsung OLED I have any experience with was the 7.7" version. It was used on one of their tablets and a similar model from Toshiba. Both would show signs of Android status-bar burn-in after just a few weeks of use. Maybe that's why they disappeared from the market. All of Samsung's current tablets use LCD.

Is there any reason to believe they have somehow succeeded where LG failed on their 55" panel?
post #6359 of 9427
Quote:
Originally Posted by sytech View Post

Quote:
Originally Posted by markrubin View Post

^^^

my first plasma was a Pioneer 50 inch purchased new in 1999: it was $14,950.00: and it never had burn in

The difference is plasma had to overcome economies of scale to reduce price, whereas OLED has to overcome technical problems of 90% failure rates.

 

Sure, but failure rates for plasma on TV sized screens (37", etc.) were exceedingly high in the very beginning too, no?

post #6360 of 9427
Quote:
Originally Posted by mypretty1 View Post


I gather the LG cannot be wall-mounted. Is this also true for the Samsung?

Does the Samsung come with the frame shown on some photos? Or can it be removed?

Found some additional info. See page 8 of the quick-start guide here:

http://downloadcenter.samsung.com/content/EM/201307/20130701161910466/[S9C]BN68-05356A-01Kor-0624-2.pdf

You will see the frame comes pre-attached to the TV and is not removable. Only the little "kick-stand" like device in the center is installed by the user. Neither the LG or Samsung have any mounting holes on the back.
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