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LG 55EA8800 Gallery OLED TV at CES 2014 - Page 2

post #31 of 52
Quote:
Originally Posted by xrox View Post
 
Quote:
Originally Posted by tgm1024 View Post

I'd like to see the presentation if you could PM it to me.  I'm totally up for that part of this to be true either way: I have no skin in the game, and would love to learn.  BTW, I'm frustrated with LG.  It seems that every time someone over there tries to explain something they contradict it later.  It's almost as if their marketing team just cant shut up long enough for the engineers to talk properly.

I want to know more about the stacking interactions as well.

The dichromatic blue + yellow phosphor in the documents is a confusing one.  Because they both are emission entities, they get labled blue + yellow, and sometimes blue + red/green carelessly.  I went with the information and explanation from ynotgoal a long time ago because it followed the kodak patent that presumably everything was based upon.

That, and I believe that dichromatic white from a blue LED and yellow phosphor was the first way a white LED was created a long time ago.

In the LG case the yellow (or red/green) emitter is NOT a photo excited phosphor like you see in LEDs/Plasma/Fluourescent light bulbs. They are seperate red and green phosphorescent EL materials (ie - singlet+triplet).

 

I don't doubt you on this detail, but I would love confirmation from this in engineering paper form.  ynotgoal's argument was exceedingly convincing months ago.  BTW, curious: a phosphorescent driven how?  A thin film luminescent just like the OLED underneath current/voltage driven?

 

PS.  Thanks for the image over PM Slacker.  I look forward to seeing more.

 

What we may be seeing here is the difference between what the engineers within LG would tell us vs. how the reps and marketing were told to explain it.  This of course could mean it goes either way.

post #32 of 52
Quote:
Originally Posted by tgm1024 View Post

I need confirmation from this in engineering paper form.  BTW, curious: a phosphorescent driven how?  A thin film luminescent just like the OLED underneath current/voltage driven?
Yes, electron hole recombination process. Phosphorescent OLED materials emit light from both the singlet and triplet states. This is why they tend to have such higher efficiencies than fluorescent EL materials.
Edited by xrox - 1/20/14 at 10:50am
post #33 of 52
Quote:
Originally Posted by xrox View Post
 
Quote:
Originally Posted by tgm1024 View Post

I need confirmation from this in engineering paper form.  BTW, curious: a phosphorescent driven how?  A thin film luminescent just like the OLED underneath current/voltage driven?
Yes, electron hole recombination process. Phosphorescent OLED materials emit light from both the singlet and triplet states. This is why they tend to have such higher efficiencies than luminescent materials.

 

Thanks.  This raises a ton of questions.  Are you saying that's entirely non-excited by the blue underneath (no stokes shift) and driven by current/voltage of its own?  Why then not replace the underlying OLED with that?  How do they mitigate the output of that R/G later (a single Y layer or two?) to match a decaying blue?  And I'm assuming that this is superior because phosphors tend to be "noisy" and emit too broadly in the EM spectrum (compared to dedicated spectral emitters like LED/OLED, etc).

post #34 of 52
Quote:
Originally Posted by tgm1024 View Post

I don't doubt you on this detail, but I would love confirmation from this in engineering paper form.  ynotgoal's argument was exceedingly convincing months ago.  BTW, curious: a phosphorescent driven how?  A thin film luminescent just like the OLED underneath current/voltage driven?

PS.  Thanks for the image over PM Slacker.  I look forward to seeing more.

What we may be seeing here is the difference between what the engineers within LG would tell us vs. how the reps and marketing were told to explain it.  This of course could mean it goes either way.

What Slacker and xrox are saying is correct and is the same thing I was saying. I think it would be helpful to you to not think in terms of LED or phosphors at all.
post #35 of 52
Quote:
Originally Posted by ynotgoal View Post
 
Quote:
Originally Posted by tgm1024 View Post

I don't doubt you on this detail, but I would love confirmation from this in engineering paper form.  ynotgoal's argument was exceedingly convincing months ago.  BTW, curious: a phosphorescent driven how?  A thin film luminescent just like the OLED underneath current/voltage driven?

PS.  Thanks for the image over PM Slacker.  I look forward to seeing more.

What we may be seeing here is the difference between what the engineers within LG would tell us vs. how the reps and marketing were told to explain it.  This of course could mean it goes either way.

What Slacker and xrox are saying is correct and is the same thing I was saying. I think it would be helpful to you to not think in terms of LED or phosphors at all.

 

I agree.  I went back and re-read your posts.  I was confusing the electrically driven phosphorescents with blue excited yellow phosphor.

 

Note to others reading, this is a very tightly constrained discussion only interested to those interested in the bottom layer physics of the device.

 

My questions are now:

  1. Is the red/green (yellow layer) in every way the same thing physically as an OLED?
  2. Are they actively throttling down that yellow layer to match a decaying blue, and if so how?

Edited by tgm1024 - 1/20/14 at 9:04am
post #36 of 52
Quote:
Originally Posted by tgm1024 View Post

My questions are now:
  1. Is the red/green (yellow layer) in every way the same thing physically as an OLED?
  2. Are they actively throttling down that yellow layer to match a decaying blue, and if so how?

Someone can correct me here if I'm wrong but reading the papers from Kodak I interpret the Blue and RG emitter layer function to be the same (aside from the triplet state emission in the RG). Since the Blue emitter is seperate from the RG emitter there must be a charge generator in between them in order to enable hole-electron pairs to combine in both emitter sites at the same time. In the Kodak paper this generator is the adjacent injection layers (HIL/EIL combination layer).

One way to control luminance of seperate emitting layers within a stacked subpixel is to control the layer thickness. I don't think they could ever modulate the seperate emitters within a subpixel if that is what you mean. This is my interpretation anyway.
post #37 of 52
Quote:
Originally Posted by xrox View Post
 
Quote:
Originally Posted by tgm1024 View Post

My questions are now:
  1. Is the red/green (yellow layer) in every way the same thing physically as an OLED?
  2. Are they actively throttling down that yellow layer to match a decaying blue, and if so how?

Someone can correct me here if I'm wrong but reading the papers from Kodak I interpret the Blue and RG emitter layer function to be the same (aside from the triplet state emission in the RG). Since the Blue emitter is seperate from the RG emitter there must be a charge generator in between them in order to enable hole-electron pairs to combine in both emitter sites at the same time. In the Kodak paper this generator is the adjacent injection layers (HIL/EIL combination layer).

One way to control luminance of seperate emitting layers within a stacked subpixel is to control the layer thickness. I don't think they could ever modulate the seperate emitters within a subpixel if that is what you mean. This is my interpretation anyway.

 

I don't think so either (regarding modulation tailoring of the RG to match the blue wear).  Perhaps with an extremely odd feedback from the blue (some electrical characteristic must change as it wears) that alters the modulation current to the RG emitter, but that's beyond guessing.

 

Regarding the Kodak patents, I can't quite discern what they're saying.

post #38 of 52
You can believe the OLED material is in pixels if it helps you, but it isn't. It's not pushed through a screen, it's not patterned using any kind of mask, there is no litho-type process. There is simply a layer of OLED material deposited across the substrate. I understand that the driving of that OLED material on a sub-pixel basis is complex electrically, but that's why I made the analogy to LCOS. Really, the analogy applies somewhat to liquid crystal in general, though you will find that your TV has some structure in place to ensure that the liquid stays in each pixel... The LG OLED doesn't have to worry about that because one the OLED material returns to solid form, it's just there.

The ability to evenly place a micro-thin layer of OLED material across a 55-inch TV is obviously not proving as easy as was once hoped. But they are simply not patterning the OLED layer. There is no mask. If there were, the technology would provide no advantage over what Samsung is doing from a manufacturing standpoint. It would only have the drawback of also requiring color filters. (It still might have long-term intra-pixel stability advantages, but those do not explain why LG is pursuing it, manufacturing ease does.)
post #39 of 52
Quote:
Originally Posted by rogo View Post

You can believe the OLED material is in pixels if it helps you, but it isn't.

 

No one is saying that there is OLED material physically packetized into discrete quantities.  You're insisting on a distinction that shouldn't exist for this discussion.  Once you power on the cathode/anode pair, you end up with regions of emission that are then cleaned up by what looks like a blocking grid between the RGB (and W if they use one) filters.  Each of those is a subpixel.  Doesn't matter that it's merely an activated section of a unified layer underneath---this doesn't change the term pixel or subpixel at all.  What forms the subpixel is the region underneath activated by current/voltage, PLUS the filter (and if you wish to regard a blocking region, then that as well).  And the subpixels collectively form a pixel.

 

What I find really interesting is what Slacker discussed above.  Plus I don't understand the activation characteristics of that yellow (R/G) layer.  Understanding this is as important as it was to understand, say, the characteristics of the LCD elements for LCD's.  Understanding the underpinnings helps to unravel the causes of all subsequent issues of the display.


Edited by tgm1024 - 1/21/14 at 5:42am
post #40 of 52
Quote:
Originally Posted by tgm1024 View Post

  Doesn't matter that it's merely an activated section of a unified layer underneath---this doesn't change the term pixel or subpixel at all. 

It matters gigantically. The OLED doesn't have to be formed/patterned into pixels. Pixels only happen thanks to the transistors and color filters. That's a multi-billion-dollar difference from how RGB OLED is made. I'm sorry you can't see how that matters.
Quote:
What forms the subpixel is the region underneath activated by current/voltage, PLUS the filter (and if you wish to regard a blocking region, then that as well).  And the subpixels collectively form a pixel.

Of course they form a pixel, but the OLED material is almost incidental to the equation.
Quote:
What I find really interesting is what Slacker discussed above.  Plus I don't understand the activation characteristics of that yellow (R/G) layer.  Understanding this is as important as it was to understand, say, the characteristics of the LCD elements for LCD's.  Understanding the underpinnings helps to unravel the causes of all subsequent issues of the display.

Knock yourself out on understanding the technology and then leading yourself to believe you can understand picture-quality or other issues 3-5 years down the road. That seems like a pointless endeavor to me, but if you enjoy it feel free.

We still have pretty lousy understanding on the forums of why LCDs have terrible uniformity in most cases. People still believe completely untrue things about backlight bleed, which is ridiculously easy to understand, for example. But they have no trouble hating the bleed despite no ability to fix it.

I don't understand how your personal knowledge of how LG's technology works will let you enjoy or improve the picture down the road. But if it does, great.

In the meantime, I am done explaining how the displays are made. If people want to continue under some misapprehension, they are free to do so.
post #41 of 52
Quote:
Originally Posted by rogo View Post
 
Quote:
Originally Posted by tgm1024 View Post

  Doesn't matter that it's merely an activated section of a unified layer underneath---this doesn't change the term pixel or subpixel at all. 

It matters gigantically. The OLED doesn't have to be formed/patterned into pixels. Pixels only happen thanks to the transistors and color filters. That's a multi-billion-dollar difference from how RGB OLED is made. I'm sorry you can't see how that matters.

 

Rogo, of course I see how that matters in terms of how the TVs are made, maybe might last, maybe might cost more or less, etc.  What I am saying doesn't matter is this strange definition of yours that LG isn't using pixels or subpixels.  "Pixels only happen thanks to the transistors and color filters".  I don't care.  They're pixels.  They're also subpixels.  And the OLED material underneath, with or without a wall around it, along with it's stack is what we're discussing.

 

Look, it's clear that you seem to think that there's a fundamental misunderstanding here regarding the sheet of OLED material, or whatever you want to call it.  There just isn't.  When we refer to subpixels, we're talking about the totality of the stack, not how it's made.  It's a region that is triggered into light by the electronics.

 

You seem to think that I don't understand that it's not a walled off chunk of OLED material.  That I view it as some kind of bucket of OLED, or droplet, or whatever.  That's unfortunate, but I'll live with it.

post #42 of 52
Quote:
Originally Posted by xrox View Post
 
Quote:
Originally Posted by tgm1024 View Post

I need confirmation from this in engineering paper form.  BTW, curious: a phosphorescent driven how?  A thin film luminescent just like the OLED underneath current/voltage driven?
Yes, electron hole recombination process. Phosphorescent OLED materials emit light from both the singlet and triplet states. This is why they tend to have such higher efficiencies than fluorescent EL materials.

 

I read through Unversal Display Corporation's explanation of PHOLED, and it's beyond my understanding currently.  According to the Motley Fool (Rumored LG Deal: Apple's OLED iWatch Is on the Way), they have about 3000 OLED patents and license some of them to LG.  Is the UDC's PHOLED what is driving the LG OLED TVs?

 

 

post #43 of 52
Quote:
Originally Posted by tgm1024 View Post

I read through Unversal Display Corporation's explanation of PHOLED, and it's beyond my understanding currently.  According to the Motley Fool (Rumored LG Deal: Apple's OLED iWatch Is on the Way), they have about 3000 OLED patents and license some of them to LG.  Is the UDC's PHOLED what is driving the LG OLED TVs?


It is their red/green phosphorescent materials that make up the "yellow" emitter layer in LG's televisions. The blue fluorescent materials are supplied by another company.

They are also the supplier for the red and green emitter materials in Samsung's smartphones and at least the red in the Samsung televisions.
post #44 of 52
As I said, tgm, I give up. You are entitled to your beliefs.
post #45 of 52
Quote:
Originally Posted by rogo View Post

As I said, tgm, I give up. You are entitled to your beliefs.

 

Ironically, I was just going to add almost this exact same line to my post this morning.  Walking away from this one is the only sensible move for each of us.  I can't possibly say any more toward it...there's seriously nothing left.

post #46 of 52
Nobody is talking about burn in screen's with OLED.
post #47 of 52
Finally they have hit the streets, who's got one ???
post #48 of 52
smile.gif
post #49 of 52
Quote:
Originally Posted by Cleveland Plasma View Post

Finally they have hit the streets, who's got one ???

An imaginary one for now, are you also going to be selling the 55 4k version?
post #50 of 52
Quote:
Originally Posted by 6athome View Post

Nobody is talking about burn in screen's with OLED.

 

We do from time to time, but we really should be talking about it more.

 

Right now the OLED's have these issues, not in order(AFAICT):

  • Not bright enough for blur mitigation yet?
  • 4K not available yet
  • Potential/Unverified IR/BI --- We saw a floor display with one pretty bad, but not much since then, have we?
  • Lifespan.  Related to IR/BI: uneven wear.  Blue fade, etc., etc., etc.....
  • Only 55" or price goes nuts.

 

I can't tell if I envy those buying one now, or feel bad for them.

post #51 of 52
Based on how the positive is largely outweighing the negative in all pro reviews and owner impressions so far, I wouldn't feel too bad. 30k hours before blue fade seems to be the figure I saw quoted prior. That's less than plasma and LCD but watching an average of 8 hours a day should afford 10 years of usable life before any noticeable degradation. Of course, getting an ext. warranty on these is probably a wise move.

EDIT: Leaving this post up for posterity's sake. Talk about premature.
Edited by vinnie97 - 4/2/14 at 11:32am
post #52 of 52
Quote:
Originally Posted by remush View Post

An imaginary one for now, are you also going to be selling the 55 4k version?
You bet wink.gif
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