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How will OLED compare to LED/LCD on blur reduction by 2018?

  • No better than a 60Hz LED/LCD (same as today - no improvement)

    Votes: 3 25.0%
  • Equivalent to a 120Hz native refresh LED/LCD with 2X frame interpolation (resulting in 120fps SOE)

    Votes: 0 0.0%
  • Equivalent to a 240Hz effective refresh rate LED/LCD with 2X frame interpolation and 1/2 backlight s

    Votes: 0 0.0%
  • Equivalent to a 240Hz native refresh LED/LCD with 4X extreme frame interpolation (resulting in 240fp

    Votes: 0 0.0%
  • Equivalent to a 360Hz effective reresh rate LED/LCD with 2X frame interpolation and 1/3 backlight sc

    Votes: 0 0.0%
  • Equivalent to a 480Hz effective refresh rate LED/LCD with 2X frame interpolation and 1/4 backlight s

    Votes: 0 0.0%
  • Equivaent to a 480 effective refresh rate LED/LCD with 4X extreme frame interpolation and 1/2 backli

    Votes: 0 0.0%
  • Equivalent to plasma one way or the other (600Hz equivalent, ~1200 lines of motion resolution)

    Votes: 2 16.7%
  • Better than plasma and close to CRT (the Holy Grail)

    Votes: 7 58.3%

  • Total voters
    12
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Discussion Starter #1
LGs WOLED is a sample and hold display reported by HDTVTEST to have 300 lines of motion resolution (the same as a 60Hz LCD, about as bad as it can get).


I'm curious in anyone's view on how this can be improved upon.


If the refresh rate can be increased to 120Hz and eventually 240Hz native, this combined with full motion interpolation ought to result in similar improvements to what LED/LCD has achieved with motion blur reduction, though with a more severe 'Soap Opera Effect'


Impulse mode would require increased current density through the individual TFTs of the backplane, and since I am beginning to suspect threshold-voltage-shift related issues caused by current density as the Achilles Heel of LGs existing WOLED technology, it does not appear that OLED has an easy path to capitalizing on impulse mode.


Is there any understanding of maximum current-density and/or peak light output from OLED pixels?

If OLED technology is fundamentally limited to a slower refresh rate than state-of-the-art LCD and if it is already operating at close to peak light output per pixel, I don't see how it's ever going to be able to offer the same (barely acceptable) improvements in blur reduction that today's leading LED/LCDs have achieved.


Is there something I am missing?
 

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Quote:
Originally Posted by fafrd  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof/0_50#post_24649287


LGs WOLED is a sample and hold display reported by HDTVTEST to have 300 lines of motion resolution (the same as a 60Hz LCD, about as bad as it can get).


I'm curious in anyone's view on how this can be improved upon.
Software interpolation or trying to emulate an impulse display. Basically the same things LCDs have done. Any active matrix OLED is by it's very nature going to be a sample and hold display. We know the videophile crowd won't like the first solution. Unfortunately, emulating an impulse display will be tricky because you will have to drive it harder for a shorter duration to achieve the same perceived brightness. This means you're stressing the phosphors more and are reducing their lifetime. The shorter the on time, the harder you have to drive it.


There needs to be a breakthrough in efficiency to get more lumens/watt out of them. This will reduce heat buildup and increase brightness. I don't know where they're at currently for lm/W, so I can't say the feasibility or likelihood of this.
 

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Quote:
Originally Posted by NintendoManiac64  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof/0_100#post_24655067


The Oculus DK2 is relevant to this thread, it uses a 75Hz OLED 1080p (pentile though) display with black-frame insertion, resulting in only 2ms persistence.


Relevant thread and posts from the Chief Blur Buster himself:
https://developer.oculusvr.com/forums/viewtopic.php?f=26&t=7181
Because it's running games, the Oculus is not restricted to 60Hz like televisions are, which is what enables them to do this.


75Hz has a frame time of 13.3ms, so 2ms of image persistence means that the display is blanked for 11.3ms

If you wanted to achieve 2ms persistence at 60Hz (16.7ms) it means the display is blanked for 14.7ms - far longer, which means that you are going to have more flicker, and the display is going to be quite a bit dimmer.



The only real solution is to move away from old standards.

24Hz has a frame time of 41.7ms!


2ms persistence is basically impossible with that. You need a display which is significantly brighter than we have today, and even if you solved that part, you would have so much flicker it would be unwatchable.


Your only options are to either:

1. Increase the persistence to reduce flicker, which means worse motion handling.

2. Repeat frames to increase the refresh rate. E.g. 24x3 = 72Hz, so flicker would be tolerable, but repeating frames introduces judder.

3. Use motion interpolation to increase the framerate. Interpolate to 120Hz and you will have extremely low flicker, but are almost certainly introducing artifacts.

4. Move away from 24fps altogether, and start shooting films at 48fps or greater.


I would rather see films shot at multiples of 60 rather than 24 though, if we are dropping the legacy formats.

It's a higher framerate, and 60Hz works on just about anything. 48Hz is unsupported on 99% of the displays currently out there.
 

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I would just like to point out that the OP did not ask about OLED TVs but about OLED panel technology in general.


Therefore the Oculus Rift is still relevant.
 

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Discussion Starter #6

Quote:
Originally Posted by NintendoManiac64  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24655556


I would just like to point out that the OP did not ask about OLED TVs but about OLED panel technology in general.


Therefore the Oculus Rift is still relevant.

Yes, any means by which OLED can increase peak light output opens up the possibility of an impulse mode to reduce motion blur in the same way as LCDs with a bright scanning backlight.


So any insight on what limits the peak light output on OLEDs and whether LGs current generation of WOLED TVs. for example, would be able to double peak light output while halving the pixel ON time would be interesting.


If OLEDs are already pretty much peak-light-output limited, than impulse mode is not going to offer much of a solution to reducing motion blur If the limitation on OLED light output is some sort of cumulative power measure, so twice as bright for half as long is essentially no worse than leaving the pixel on for the entire time but at half intensity, they should eventually be able to offer an impulse mode like CRT and approximated by scanning backlights to reduce pixel persistence and motion blur with it.


I'm just not familiar with what the physics are underlying OLED light output limitations.


If the Oculus RIFT is able to employ an impulse mode, that is great, but if can only be done because the light output is effectively very low because you are wearing a headset designed to capitalize on your eyes sensitivity in very dark surroundings, that is less great and means the same solution may not be easily deployed in flat-panel OLED televisions (which can't be designed to only work in pitch black surroundings).
 

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As soon as I saw this square yard of options:
Quote:
No better than a 60Hz LED/LCD (same as today - no improvement)

Equivalent to a 120Hz native refresh LED/LCD with 2X frame interpolation (resulting in 120fps SOE)

Equivalent to a 240Hz effective refresh rate LED/LCD with 2X frame interpolation and 1/2 backlight scanning (120fps SOE)

Equivalent to a 240Hz native refresh LED/LCD with 4X extreme frame interpolation (resulting in 240fps SOE)

Equivalent to a 360Hz effective reresh rate LED/LCD with 2X frame interpolation and 1/3 backlight scanning (120fps SOE)

Equivalent to a 480Hz effective refresh rate LED/LCD with 2X frame interpolation and 1/4 backlight scanning (120fps SOE)

Equivaent to a 480 effective refresh rate LED/LCD with 4X extreme frame interpolation and 1/2 backlight scanning (240fps SOE)

Equivalent to plasma one way or the other (600Hz equivalent, ~1200 lines of motion resolution)

Better than plasma and close to CRT (the Holy Grail)
....I knew you were the author of it.  LOL....

 

I don't view CRT as the Holy Grail.

 

I also think we need to retire this concept of "lines of motion resolution"...These days I think the metrics need to be expressed separately (persistence, GtG, frame rate, max luminosity).
 

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Discussion Starter #8

Quote:
Originally Posted by tgm1024  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24661003


As soon as I saw this square yard of options:
Quote:
No better than a 60Hz LED/LCD (same as today - no improvement)


Equivalent to a 120Hz native refresh LED/LCD with 2X frame interpolation (resulting in 120fps SOE)


Equivalent to a 240Hz effective refresh rate LED/LCD with 2X frame interpolation and 1/2 backlight scanning (120fps SOE)


Equivalent to a 240Hz native refresh LED/LCD with 4X extreme frame interpolation (resulting in 240fps SOE)


Equivalent to a 360Hz effective reresh rate LED/LCD with 2X frame interpolation and 1/3 backlight scanning (120fps SOE)


Equivalent to a 480Hz effective refresh rate LED/LCD with 2X frame interpolation and 1/4 backlight scanning (120fps SOE)


Equivaent to a 480 effective refresh rate LED/LCD with 4X extreme frame interpolation and 1/2 backlight scanning (240fps SOE)


Equivalent to plasma one way or the other (600Hz equivalent, ~1200 lines of motion resolution)


Better than plasma and close to CRT (the Holy Grail)
....I knew you were the author of it.  LOL....


I don't view CRT as the Holy Grail.


I also think we need to retire this concept of "lines of motion resolution"...These days I think the metrics need to be expressed separately (persistence, GtG, frame rate, max luminosity).

Guilty as charged



The poll was stupid but what I was hoping to get a bit better understanding of is the fundamental limits of OLED and which avenues OLED may have to reduce motion blur (persistence).


I don't understand if there is a peak brightness limit on OLED and if they already operating at close to that limit or not.


I just saw that the LG WOLED supports passive 3D, so that ought to mean that there is at least a 2X increase in brightness possible in 2D mode.


The speed of OLED is supposed to be very good, so if there is a 2X increase in brightness possible, that should mean persistence can be reduced by at least 50%.


And then in terms of native refresh rate, I don't know if 60fps is the max or if OLED can refresh at 120Hz and take advantage of motion interpolation.


Just trying to understand if LED has a fundamental disadvantage versus LED/LCD in the area of image blur or if it can make use of similar techniques to reduce motion blur in the future.


p.s. and you are right, lines of motion resolution is a dumb spec - pixel ON time or persistence and corresponding brightness is more accurate but more cumbersome.
 

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Quote:
Originally Posted by fafrd  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24661861



I don't understand if there is a peak brightness limit on OLED and if they already operating at close to that limit or not.

They are no where near peak brightness for OLED's. The functional limitation right now is power consumption and lifetime. The S5 has a peak brightness of nearly 700 nits but Samsung purposely made it so that brightness was outside of the user's control. You can only hit that peak when you are in bright sunlight and the automatic brightness control is on.


This Lumiblade OLED lighting system shows a maximum luminance of 2,000 nits per OLED.

http://www.lumiblade-experience.com/assets/journalists/documents/Product%20Sheet%20LivingSculpture%203D%20module%20system%20(GB)%20102013.pdf


As the materials get more efficient, vendors will have to balance maximum luminance with lifetime. I would expect continuance improvement with this spec over time and a discontinuous jump if anybody manages to create a phosphorescent blue material with a good lifetime.
 

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Discussion Starter #10

Quote:
Originally Posted by slacker711  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24662128

Quote:
Originally Posted by fafrd  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24661861



I don't understand if there is a peak brightness limit on OLED and if they already operating at close to that limit or not.

They are no where near peak brightness for OLED's. The functional limitation right now is power consumption and lifetime. The S5 has a peak brightness of nearly 700 nits but Samsung purposely made it so that brightness was outside of the user's control. You can only hit that peak when you are in bright sunlight and the automatic brightness control is on.


This Lumiblade OLED lighting system shows a maximum luminance of 2,000 nits per OLED.

http://www.lumiblade-experience.com/assets/journalists/documents/Product%20Sheet%20LivingSculpture%203D%20module%20system%20(GB)%20102013.pdf


As the materials get more efficient, vendors will have to balance maximum luminance with lifetime. I would expect continuance improvement with this spec over time and a discontinuous jump if anybody manages to create a phosphorescent blue material with a good lifetime.

Thanks for the info. So if brightness is doubled for half the time (meaning average power is identical), does it mean that aging is accelerated or not?


If they have lots of headroom to increase brightness and panel refresh is quick enough to achieve 240 or 480 Hz, it seems like there would be lots of ways to make use of an impulse mode to reduce persistence / motion blur. And even if the refresh rate can not be accelerated to much more than 60fps, a few pseudo-global signals and some simple pixel logic would allow for the equivalent of a scanning backlight (light up segments sequentially).
 

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Quote:
Originally Posted by fafrd  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24662636


Thanks for the info. So if brightness is doubled for half the time (meaning average power is identical), does it mean that aging is accelerated or not?


If they have lots of headroom to increase brightness and panel refresh is quick enough to achieve 240 or 480 Hz, it seems like there would be lots of ways to make use of an impulse mode to reduce persistence / motion blur. And even if the refresh rate can not be accelerated to much more than 60fps, a few pseudo-global signals and some simple pixel logic would allow for the equivalent of a scanning backlight (light up segments sequentially).

The relationship between luminance and lifetime isnt linear so doubling the brightness while halving the "on-time" would reduce the overall lifetime of the materials. The drop-off doesnt look terrible though when I look at these numbers from LG Chem for a white OLED.




My guess though is that LG would first concentrate on improving lifetimes before making the trade-off down the road.
 

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Quote:
Originally Posted by slacker711  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof/0_60#post_24662762

 
Quote:
Originally Posted by fafrd  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24662636


Thanks for the info. So if brightness is doubled for half the time (meaning average power is identical), does it mean that aging is accelerated or not?


If they have lots of headroom to increase brightness and panel refresh is quick enough to achieve 240 or 480 Hz, it seems like there would be lots of ways to make use of an impulse mode to reduce persistence / motion blur. And even if the refresh rate can not be accelerated to much more than 60fps, a few pseudo-global signals and some simple pixel logic would allow for the equivalent of a scanning backlight (light up segments sequentially).

The relationship between luminance and lifetime isnt linear so doubling the brightness while halving the "on-time" would reduce the overall lifetime of the materials. The drop-off doesnt look terrible though when I look at these numbers from LG Chem for a white OLED.




My guess though is that LG would first concentrate on improving lifetimes before making the trade-off down the road.
 

^^^Did you post the right graph?
 

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Quote:
Originally Posted by tgm1024  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24662938


^^^Did you post the right graph?

The graph isnt for OLED displays, but it does give the relationship between luminance and lifetime for OLED lighting. I cant say for certain that the ratio holds exactly for lower luminance levels, but the fundamental idea that doubling the luminance will more than halve the lifetime of the materials is true.
 

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Yes, an OLED only passes 300 lines on the MOTION TEST. Find me 1 complaint about motion with ACTUAL CONTENT, either from a reviewer or owner. Most reviews only mention the motion res test, which by the way was specifically created to favor plasma, but fail to run other tests such as image smearing/trailing motion tests, or phophor lag tests. These additional tests would clearly show that LED LCD with scanning backlight and plasma, clearly have some serious motion issues and they all pass 1080 lines on the "motion resolution test". Don't drink the motion test coolaid and believe that it's the only measurement for great motion.


I'm one of the pickiest SOBs when it comes to motion and almost every tech other then CRT has caused me issues with motion. I have every motion test known to man, and ran them all on the LG OLED and many LCDs, Plasmas, DLPs, and LCOS projectors and I can definitely say that overall the OLED is only second to CRT. **** the one single motion test they do run. They should test overall motion with many more varied tests.


BTW, as a few reviews have mentioned, it's possible to run the LG OLED with Dejudder and Deblur at setting of 0 which raises the motion res to over 600 lines and doesn't add SOE at all. NOt sure how they do this technically, and one would assume frame interpolation but their is no evidence of SOE with these settings, so I'd say the motion res right now is 600 lines for ALL CONTENT.


I'm not saying it wouldn't be nice to have some kind of Dark frame insertion in the future, but as of now the motion is GREAT on OLED and I don't think people will have any issues what so ever. I will be certainly buying the upcoming 4K 65", even if the motion res is still only 600.
 

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What we really need is higher frame rate content, e.g. 120fps instead of the traditional 60fps. That's the only way to improve motion that doesn't create new problems (problems like: visible flicker, motion interpolation artifacts, and reduced brightness, depending on the method).
 

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Discussion Starter #16

Quote:
Originally Posted by Luke M  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24664682


What we really need is higher frame rate content, e.g. 120fps instead of the traditional 60fps. That's the only way to improve motion that doesn't create new problems (problems like: visible flicker, motion interpolation artifacts, and reduced brightness, depending on the method).

What is the refresh rate of an LG WOLED? Can the frame rate be increased in future generations and if so, to what?
 

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Quote:
Originally Posted by conan48  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof/0_60#post_24664524


I have every motion test known to man
 

What motion tests would those be?
 

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Quote:
Originally Posted by fafrd  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof/0_100#post_24664745


What is the refresh rate of an LG WOLED? Can the frame rate be increased in future generations and if so, to what?

According to

http://www.displaymate.com/LG_OLED_TV_ShootOut_1.htm


it's 120Hz. The response time is far superior to LCD (LG claims 0.1ms), so much higher refresh rates would be possible.
 

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According Fafrd true scanning backlight would solve all motion problems, no disadvantages, all it requires is a brighter backlight .. So why just not start a ''When will there be a true scanning backlight OLED'' thread?

.


Part of the motion problems are source related, there is nothing a TV can do about that.. Also we need higher frame rates.
 

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Discussion Starter #20

Quote:
Originally Posted by 8mile13  /t/1529060/outlook-for-blur-reduction-in-oled-or-the-lack-thereof#post_24665546


According Fafrd true scanning backlight would solve all motion problems, no disadvantages, all it requires is a brighter backlight .. So why just not start a ''When will there be a true scanning backlight OLED'' thread?

.


Part of the motion problems are source related, there is nothing a TV can do about that.. Also we need higher frame rates.

It's not so much 'scanning backlight OLED' as 'impulse mode OLED'


And the objective is not to eliminate ALL motion problems (such as those that are source-related) but to approach CRT-like motion blur, generally considered the gold standard.


CRT is much brighter over a much shorter persistence period than virtually any other mainstream display technology. Even with 60fps source material, it does a good job avoiding motion blur. If instantaneous brightness of OLED can be increased and persistence decreased (the pixel is pulsed ON for only a short portion of the full 16.7ms @ 60Hz refresh), the apparent motion blur of OLED to be closer to that of CRT.


CRT is raster, the entire screen is not strobed at once, and scanning backlight of LED/LCD approach the same raster-like strobing behavior by strobing a sequence of segments rather than the entire screen at once. An impulse mode OLED could do the same, and taken to the extreme, entire lines could be strobed on in sequence, which would deliver a raster-like strobing effect very similar to that delivered by CRT.


The increased instantaneous brightness is the key, and if increased light output, even for a decreased time, results in shortened lifespan for OLED, that may be the reason this is not a viable solution. Or there may be other more important fish to fry for the first generation OLEDs, such as assuring that the panels don't become swiss cheese during the first months of use...
 
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