OLED TVs: Technology Advancements Thread - Page 114

Two of the key features of White OLED (yes, it's multi-layer device that includes Blue) for display purposes are its lifetime and its excellent color stability: all emitters decrease at the same rate. There is plenty of technical documentation from Kodak on the web as pointed out in several topics. One documented example has virtually unchanged CIE coordinates (less than 0.003 CIE units) after the 50% lifetime period, so that aging effects on color balance and grey scale should be minimal.

Ferro, I'm not arguing that point so much as pointing out the mechanism by which it's achieved -- presuming that it pans out in real-world use.

The stacking method doesn't magically allow the blue to age evenly when blue aging has been a problem. What it appears to be doing, however, is allowing for the use of a blue that can't be use in a non-stacked, non-white OLED. And that blue doesn't suffer the aging issue.

It's a technical point.

Anyway, I actually trust that LG isn't bringing anything to market that won't perform well for at least 5 years of heavy use (and 10 years of lighter use). But I believe Samsung will manage to achieve the same using their entirely different approach as well.

^^^ I would think that's "magical" I still don't understand why that would be the case.


And your quote on the other thread. I just want to ask: How long does it take for OLED 4" top reach LCD 4" in cost parity? Don't you think it took faster than either of us even expected?


It's OLED. Not LED. And it is not white. It is RGB stacked to produce white and later separated with RGBW color filter.There are many reasons why they do this.


Yes, but genuine question: Does AM automatically means it is sample and hold? Most of the literature I read is that it is pulse based. And it is current driven vs LCD which is voltage driven though both are AM. Here's xrox's recent post:



Thanks for the info. I'll have to read up more. I'm obviously falling behind because I've not read anything producing 120fps natively. What graphics card setup do you use?

Any "3D Vision" capable display will accept a 100/120Hz input, and any modern graphics card should be capable of sending it that. (it was introduced in 2008) Most of these displays are TN LCDs, though there are some DLP projectors as well.

Most games these days are console ports, where the graphics hardware is less powerful than PC GPUs by at least an order of magnitude. If you have SLI, it's not difficult to reach 120fps with most modern games. (personally, I find microstutter from SLI to be problematic, and stick to playing all games at 60fps)

If you aren't playing the very latest gameswhich is often the case with competitive gamingyou can run just about anything at 120fps.

It is still Sample and Hold, but since OLED doesn't have backlight or pixel response issues, you can simulate pluses very accurately without introducing flicker or brightness dip.

Also it has to be done due to the short lifespan of OLED.

You should dump NVIDIA and move to our side

120Hz cuts lag by ~8ms (from ~16ms).

Most consoles games are still 20-30fps, which has lag of 33.3 to 50ms. Add that on top of lag caused by the controller, processing and TV, well ...

Based on all the published material about the LG WOLED TV's, they are using White OLED with colorfilters. Which means that the blue filter will have the same deterioration (or non deterioration) as the other color filters.
Also no indication of stacked OLED layer(s).

Do you have any more accurate information that LG is using "stacked color OLED or are you confusing LG WOLED with Samsung's "Super" OLED?






Background informations about LG Displays WOLED-TV technology

I think you're right, Coolscan.

Yesterday I posted on the LG Official Announces 55" OLED thread that it appears LG is using four stacked white OLEDs, with three being filtered RGB, and one unfiltered (white). I posted a link to this article:
http://www.oled-info.com/kodak/kodak..._and_interview

I also bemoaned the fact that I couldn't find a diagram I had seen that supports this, but you just posted it.

So the stability of the white is the reason for the color stability of LG's WOLED. They get around the blue issue entirely by making blue (and red and green) with a filter.

You know, every time I see the name Kodak (who also developed digital photography, ironically, I feel sad that the US sells its patents, and that we presently are unable in many instances to conceive, develop, and manufacture in this country.

At least we're back up and running with the auto industry.

Frankly, I see no reason why Kodak couldn't develop this WOLED further and started selling it's own panels to others, except for financial difficulties they're in, but I think the company couldn't change fast enough and personally I think it didn't believe in it's own new tech, that it will take over so quickly.
Of course it's always 20/20 vision after the fact, but still I think Kodak wasn't changing it's ways fast enough even with the headstart they had. It's a shame, because Kodak was an Icon.

Kodak sold all their OLED assets to LG in 2009, so I don't think this is possible.

Yeah. You have the great engineers and technicians, and then you have business people, marketers, lawyers and the rest who either support the innovators correctly, or screw it up.

Kodak was an icon, and now it seems they're focusing on printing technology. Funny, because the deposition of OLED material on panels is like and may become more like printing.

And you're quite right, ferro. Kodak gave up its patents.

According to the most recent rumors, Apple has dropped Sharp as a supplier for the iPad 3.

The reports so far have been a little light on details so it would be tough to say if this is a "They can't build enough displays for us" issue or an "IGZO isn't ready for prime time issue".

Makes me wonder what it means, if anything, for LG's OLED mass production plans. Is IGZO really gonna be a solution for OLEDs in the near term?

I vaguely remember them retaining the right to use their own technology for some number of years. Anyone know if anything like this occurred?

Moot point- I don't think Kodak could do anything with it now.

It's not quite there yet. Most of Samsung's phone lineup for 2012 uses LCD (yes, really). Only the higher end lines use OLED. But, yes, they've done well to drive cost down. Perhaps faster than we would've hoped, although in fairness to Samsung, they've also sold a ton of those phones -- more than we would've guessed. More screens = more learning curve effects = lower prices.


Color filters don't deteriorate meaningfully over time any more. The issue is that the white is made of three layers of OLED material and in the past blue OLED has deteriorated more quickly. As addressed elsewhere, the blue LG is using should have much less of a problem (or none) in this regard.)

I'm not confused, some of you are, however.



Listen, what you just wrote is true and unbelievably misleading -- as is that diagram.


No, that's 100% wrong. They get around the blue issue mostly by using a blue OLED material that is fluorescent and wouldn't work at all in a "conventional" RGB OLED. Why does it work for LG? Because all they need from their blue is for it emit a blue light true enough such that with their red and green OLED, the final output is white.

I've explained exactly how LG is doing this several times, but I'll have to draw a diagram that actually reflects their method, because the ones people keep linking do not.

The key facts are that:

1) Every pixel on screen does have 4 sub-pixels. The emitters for those pixels are all white OLEDs.

2) Every pixel on screen has three tiny flecks of color filter, one each for red, green and blue. In that regard, they make light almost exactly the same way an LCD does -- light passes through the color filter which is bonded to the screen front (or very nearly depending on protective layers and where the BEFs and ambient filters wind up). The reasons why this is better than LCD involve the pinpoint control of the light source, whereas LCD uses a light valve approach. The light emitters are very close to the screen on OLED, so the viewing angles will be better than LCD -- even using LG's method.

3) There is no need to "pattern" the OLED material at all. It's applied in three layers using vacuum deposition. I'm not sure of the order, but for our purposes, imagine it goes red, then green, then blue. Since OLED is transparent by nature, the light all passes through the layers and comes out as white before you see it. Each transistor on the backplane controls the equivalent of one sub-pixels worth of OLED emission... One fourth of a pixel of white light. Whether that light emerges from the panel as red, green, blue or white is determined by the patterning of the color filters placed in front of the OLED layers.

4) It's convoluted to do this. Take red green and blue to make white only to use white to make red green and blue... But it results in much simpler manufacturing and allows for two key layers -- the TFT backplane and the color-filter front -- to be almost identical to what's being done on LG's existing LCD production. They aren't identical since LCD uses 3-subpixels on LCD not 4 and therefore patterns its color filters very differently, but the basics are very similar. LG is already more than expert at making TFT backplanes and color filters...

And their method of depositing OLED material is very simple. I suspect their only real challenge in manufacturing is getting the deposition just right so that the backplane illuminates the OLED material in a uniform fashion so that those 8 million sub-pixels turn on as expected and are all very similar in brightness.

Kodak's method appears to have been genius, even though it will result in a more power-thirsty display than Samsung's "true" RGB OLED. LG's displays will still use less power than LCDs (which require a lot of light because of the way the LC material blocks so much of it and the polarization requires much light to be tossed) and will be slim and lightweight. LG's method is not entirely optimal for making mobile displays, but that's not a market they are currently tackling with this method anyway.

^^ Just want to add that:
1) The subpixel you see is the color filter
2) It should be FOUR tiny flecks of color filter: RGBW

There is no white emitting layer. They probably condense it as white as the net result of the RGB emitter is white.


This is breaking news if true as the whole supply have been ramping for iPad3 since December. Can you please provide link?

Interesting... So it is PERCEIVED as a pulse even though it is actually S&H? It is more platypus than I thought.


Probably that's the problem with using Tom's Hardware as a reference.

I wish they stop trying pulse driving on current LCDs. All it does is creates multiple ghost images

http://english.etnews.com/news/detai...d=201201100006

I believe that was the original source. There are about ten billion other articles out in the last week saying Sharp has been dropped as a supplier for the iPad 3.

It'll be interesting to find out if that has anything to do with IGZO TFT quality/yields.

Really? 10bio? Amazing how cute people can get overnight. Do you actually know how much capacity Sharp has committed to this project?

I would take ETnews with a pitch of salt. Sharp was meant to replace CMI which cannot make retina display, and to a lesser extent Samsung for obvious reasons. I would be keen to see what Sharp say early next month during their earnings results

I wasn't trying to be cute, I was just pointing out that the ET article has been parroted by just about every single Apple fanboy site on the internet.

I wrote three tiny flecks, because where the white emission occurs, there won't be any color filter in theory. The white will simply pass through the front glass.

Yep.

It's been mentioned a few times already and seemingly over looked when I read this thread.

There is no such thing as a "white" OLED subpixel with today's tech they're using. They use a blue OLED which also emits energy (light) near ultra violet and they add a mix of phosphors. The mix of phosphors causes some of that near UV spectrum to be converted into red and green. Thus you end up with a "white" OLED when it all combines.

So technically speaking the LG unit is all blue OLEDs + phosphors...

There's a lot of things to discuss, like are they really doing this for the color blue?

BLUE OLED + phosphors = white output -> blue color filter

Seems a bit inefficient to me but maybe you get a better blue out of it to hit the CIE target.

Or is there some organic material they can use to make an efficient white OLED? I've seen some documented for prototypes but they all seemed to have issues.

Perhaps I have my info wrong, anyone?

Articles like this make it sound just peachy
http://www.oled-display.net/backgrou...tv-technology/



Perhaps my question should be what is LG using for a white source?

Not true. Polychromatic single layer white OLEDs are made by doping RGB emitting materials into the single layer IIRC.

I'm not sure what exactly LG's design is. I suspect it is a version of a two stacked design combining monochromatic single layer blue with polychromatic single layer Red and Green.

Thank you for this information, and for your informed posts in general. Given that LG has not released much material about their design, all of this is a real learning curve.

Perhaps I mis-spoke.

I said...

Covered the other designs I've read about

I've seen stacked designs and or aggregate side by side designs that combine RGB to make white but they are all prototypes. And they all still have stability issues/compromises.

LG claims to have a 100,000+ hour stable white. In order to make that claim they would have to use an inorganic blue I would think as you said. Or have hit a home run on their materials for blue

Perhaps I misunderstood?

I thought you meant that WOLED had to be three distinct RGB layers. Sorry.


The blue is not inorganic? The LG papers that I have only cover a two stacked design using blue fluorescent material and a seperate RGY phosphorescent material mixture. They claim a synergistic brightness effect is achieved using this design.

They claim increased blue life via new ETL and non-carbazole HTM.

Based on articles about Kodak's work with Novaled, it appears that LG is using Novaled's stacked White OLED. The same 100,000 hour lifetime is mentioned.

http://www.oled-info.com/lifetime/no...ent_white_oled

http://www.novaled.com/news/2011_07_13_pr.html

... but this doesn't mean the shift in brightness won't occur. So burn-in is still possible. Do you guys know any manufacturing method for compensating the life curve of oled materials in per-pixel (not per panel) regime?

Correct that makes sense, yes burn in will be possible. My thoughts when making those posts was 100% directed towards the color of white (white balance) being stable in the long run.

I read a patent on a compensation algorithm last year sometime for the white balance. Wish I would have posted it now. Finding it again will probably be a pain.

Thanks, that'll help fill in some of the gaps for me. If these numbers jive LG's OLED set should be really good.

Be interesting to see how Samsung is doing their blue emitter.

Filling in the gaps is an apt way of putting it. Understanding LG's design is a work in process for all of us.

It sure looks promising, even at this point.