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You are ignoring other reasons why one might change sub-pixel geometry that have nothing to do with color efficiency. The driving circuits for each sub-pixel need to go somewhere and are not symmetrical in layout for all 4 colors. This is why you get those weird shapes instead of simple rectangles of various sizes for each color. They have buried circuit traces and components inside some of those indentations. The spare room varies by pixel pitch which is why the shapes change with panel size. Obviously color efficiency plays a role too but it needs to be balanced with what they can fit in the available "dead space" of the panel.
I’m well-aware if that.

In the end, the pixel full-factor depends on the ‘dead space’ needed for subpixel circuitry, the minimum inter-subpixel distances required, and the dead space caused by any top traces routed in non-transparent metal (is that what causes the large black lines between WOLED rows?).

But no matter the pixel size and no matter how much dead space is needed for curcuitry, in the end it all translates to relative mm^2 (or rather um^2) of W, R, G and B subpixels.

Subpixel size determines current density and lifetime / aging and the only reason you’d choose a different set of active subpixel area ratios is if you decided to match performance / specifications of a larger panel with larger fill factor to the performance of a smaller panel with smaller fill factor (meaning you’ve got excess real-estate / subpixel area to burn).

I circled back and had another look at the 88Z9 subpixel shot by HDTVTEST, since that’s the smallest subpixel we’ve seen (4K @ 44” equivalent). The 88Z9 has a larger white subpixel relative to the colored subpixel than any of the other designs we’ve seen. I’d characterize it as G < B < R << W, and this should mean higher peak whites but at the expense of lower peak fully-saturated colors.

So comparing 2019 WOLED sub-pixels for different panel sizes, we’ve got:

88Z9: G < B < R << W
55C9: G = B < R < W
77C9: G < B < R < W
(and 83C1: G < B < R = W)

Obviously, this is very handwavy and wend need someone with the wherewithal to translate these pictures and eyeball estimates into measured % for each subpixel to confirm this trend definitively.

But that being said, to me it seems likely that LGD has made the decision to maintain peak white levels across different panel sizes of a generation and to use additional available pixel space on larger panel sizes to increase peak fully-saturated color levels (or just to increase lifetime if they’ve decided to fully-match color volume, even at the fully-saturated extremes).

Geometry / design changes to accommodate subpixel circuitry, but overall area does not (need to, at least)…
 

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OLED emission material market to grow 9% per year until 2025
 

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Yes, ‘On Track’ with the plan to send out samples for evaluation this month for a September ‘Market Evaluation’ checkpoint.

‘Samsung Display is set to release pilot products of the quantum-dot (QD) display for TVs and monitors this month and send them to its clients for further testing, according to the sources.’

Whether production starts this year depends critically on whether Sony says the technology is ‘good enough’ and is ready to commit some orders.

We already know what Samsung Visual Display’s feedback is likely to be (‘keep working on it for another year’) but the agreement is to allow Sony to provide an impartial 3rd-party assessment…

My guess is the chance of Samsung actually launching QD-BOLED this year is down under 10% (hugely supported by the recent rumors of communications to employees and suppliers about continued LCD production through 2022…).
 

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You could be correct - the only subpixel pictures I have access to are those from Rtings which are always from sub-77” panels.

Do you have access to any older 77” subpixel pictures?

The key point is that it’s been proven/confirmed that LGD used the same subpixel design in 2020 and 2021 for the smaller panel sizes (48”, 55”, 65”) and that that subpixel layout was designed to support either the ‘old’ (2016) 3S3C/WBC/non-Evo WOLED stack or the ‘new’ (2020) 3S4C/WBE/Evo-capable WOLED stack, while the 77” and 83” panels were not intended to support panel/stack mixing and so could have been designed for optimal WBE performance without needing to worry about WBC performance.

LGD certainly had the freedom to introduce new / optimized subpixels at 77” than they used in 2019/2020, but that doesn’t mean they did. The only way to have any idea would be to see 77” subpixel pictures from a 77C9 and a 77CX…

And while we’re on the subject, are you aware of any comparisons between color volume of different WOLED panel sizes?
Not all 77CX have the old panel. Some also have the WBE panel, so it is likely that the sub pixel structure also has not changed.
 

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Reviews show that the G1 consumes much less power. Do you people think that this means that LG could have released a G1 with a much higher peak brightness (while still having the same burn-in risk as a CX), but decided not to to reduce the burn-in risk compared to the CX?
 

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Reviews show that the G1 consumes much less power. Do you people think that this means that LG could have released a G1 with a much higher peak brightness (while still having the same burn-in risk as a CX), but decided not to to reduce the burn-in risk compared to the CX?
Yes (and the new G1-exclusive 5-year warranty is pretty solid confirmation of this).
 

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Solus to supply LG Display with HTL for OLED panels
 

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We would like to inform you that we have confirmed that a trademark for a cute mark has been applied for.
And the guessing game is over that quick.
 

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Would love to understand what guessing game you think is over…

What Samsung Display will call their QD-BOLED when it finally launches?
Samsung launching WOLED. Idk, maybe I'm wrong. The reduced power consumption of Evo seems like it's a part of this. QD OLED deserves a cooler name than eco.
 

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The State-of-the Art in IJP of OLEDs and QDs

I’ve seen multiple reports of QD-BOLED (including the one from OLED-A linked above) reporting that Samsung’s June QD-BOLED prototypes are still based on a 4S1C 4-layer blue OLED stack:

‘In Samsung’s QD-OLED manufacturing process, multiple (4) blue layer stacks are vacuum deposited and the diver supplies 4x the voltage of a single layer, which is converted is converted to a standard current across each layer, generating higher luminance at the same current.’

If this is true, either Samsung has switched to High Efficiency Blue or these June QD-BOLED prototypes are still not going to bright enough to be acceptable to Sony.

If we assume Samsung is using 4 Deuterim-based Florescent layers similar to the 2 DuPont Blue layers LGD is using in their new Evo stack, that means QD-BOLED will have ~2X the blue output of Evo-WOLED.

But that Blue Luminance is driving Red and Green (through Quantum Dots) a well as Blue, and since D65 White is composed of ~10% Blue, ~30% Red and ~60% Red, Samsung will need to size their colored subpixels accordingly and peak Blue output will be ~2X the blue light through a blue subpixel which is sized at ~10% of overall pixel area rather than the ~30% Blue subpixel size on WOLED, or 1/3rd of 200% = 67%.

So 4-layer QD-BOLED will have only 2/3rd the peak blue output of WOLED. QD-BOLED has no Blue Filter where WOLED does, so that may more than close the gap for blue, but is unlikely to close the gap for red and green where both QD-BOLED and WOLED have color filters.

Worse, when outputting white, WOLED has no color filter and so achieves a peak brightness level proportional to 2 blue layers through a white subpixel which is ~30% of total pixel area, meaning it requires green output which is ~6-times that level (through both white subpixel as well as green subpixel). So we can summarize WOLEDs peak white as composed of:

Blue = 2 layers x 30% white subpixel = 0.6
Red = ~3 x 0.6 = ~1.8
Green = ~6 x 0.6 = ~3.6
TOTAL = 5.0

Compare that to 4S1C QD-BOLED where we get:

Blue = 4 layers x 10% blue subpixel = 0.4
Red = 4 layers x 30% red subpixel = 1.2
Green = 4 layers x 60% green subpixel = 2.4
TOTAL = 4.0

Because of the much poorer efficiency of driving green through a blue Florescent OLED emitter versus the much higher efficiency with which WOLED is able to drive teen through a green Phosphorescent OLED emitter (~10 times higher efficiency per layer), peak white output of 4S1C QD-BOLED will be only ~80% of 3S4C WOLED.

Of course, QD-BOLED will be RGB color pure, and that increased color volume in the fully-saturated extremes of the gamut may more than compensate for the ~20% loss of peak white output, but it’s certainly not a slam-dunk.

If we assume the A90J has achieved ~900 Nit peak levels at 1% using a heatsink, Sony would be looking at ~720 Nit peak white levels at power consumption levels which are ~133% those of WOLED (because of 4 layers versus 3).

The one reason for hope is I don’t understand how Samsung could brand a new OLED technology ‘Evo’ if it consumes 33% more power…

So the other read is that the June prototypes are based on phosphorescent blue that does not yet achieve the full lifetime Samsung would like.

Phosphorescent blue has an efficiency that is more tan 300% that if florescent blue, so in a heartbeat, a 20% peak white deficit turns into a +140% advantage (over 2100 Nits peak instead of 720 Nits peak).

But lifetime is only ~10% of what’s needed (at last report).

But if you limit peak brightness back down to 1/3 of what it could be, you’ve got the same 20% peak white deficit (back to 720 Nits peak), but now at 44% the power consumption of WOLED rather than 133% (and hence ‘Evo’).

That would still result in a lifetime that is only ~33% of what’s needed, but if Samsung Display has found further lifetime improvements of 3x or possibly even 2x, this dog could hunt…

The recent branding of Eco must mean that Samsung is planning on launching Phosogirescebt-blue-based QD-BOLED, and so the only question is whether they can deliver the lifetime Sony considers the minimum needed to Go To Market…
 

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I’ve seen multiple reports of QD-BOLED (including the one from OLED-A linked above) reporting that Samsung’s June QD-BOLED prototypes are still based on a 4S1C 4-layer blue OLED stack:

‘In Samsung’s QD-OLED manufacturing process, multiple (4) blue layer stacks are vacuum deposited and the diver supplies 4x the voltage of a single layer, which is converted is converted to a standard current across each layer, generating higher luminance at the same current.’

If this is true, either Samsung has switched to High Efficiency Blue or these June QD-BOLED prototypes are still not going to bright enough to be acceptable to Sony.

If we assume Samsung is using 4 Deuterim-based Florescent layers similar to the 2 DuPont Blue layers LGD is using in their new Evo stack, that means QD-BOLED will have ~2X the blue output of Evo-WOLED.

But that Blue Luminance is driving Red and Green (through Quantum Dots) a well as Blue, and since D65 White is composed of ~10% Blue, ~30% Red and ~60% Red, Samsung will need to size their colored subpixels accordingly and peak Blue output will be ~2X the blue light through a blue subpixel which is sized at ~10% of overall pixel area rather than the ~30% Blue subpixel size on WOLED, or 1/3rd of 200% = 67%.

So 4-layer QD-BOLED will have only 2/3rd the peak blue output of WOLED. QD-BOLED has no Blue Filter where WOLED does, so that may more than close the gap for blue, but is unlikely to close the gap for red and green where both QD-BOLED and WOLED have color filters.

Worse, when outputting white, WOLED has no color filter and so achieves a peak brightness level proportional to 2 blue layers through a white subpixel which is ~30% of total pixel area, meaning it requires green output which is ~6-times that level (through both white subpixel as well as green subpixel). So we can summarize WOLEDs peak white as composed of:

Blue = 2 layers x 30% white subpixel = 0.6
Red = ~3 x 0.6 = ~1.8
Green = ~6 x 0.6 = ~3.6
TOTAL = 5.0

Compare that to 4S1C QD-BOLED where we get:

Blue = 4 layers x 10% blue subpixel = 0.4
Red = 4 layers x 30% red subpixel = 1.2
Green = 4 layers x 60% green subpixel = 2.4
TOTAL = 4.0

Because of the much poorer efficiency of driving green through a blue Florescent OLED emitter versus the much higher efficiency with which WOLED is able to drive teen through a green Phosphorescent OLED emitter (~10 times higher efficiency per layer), peak white output of 4S1C QD-BOLED will be only ~80% of 3S4C WOLED.

Of course, QD-BOLED will be RGB color pure, and that increased color volume in the fully-saturated extremes of the gamut may more than compensate for the ~20% loss of peak white output, but it’s certainly not a slam-dunk.

If we assume the A90J has achieved ~900 Nit peak levels at 1% using a heatsink, Sony would be looking at ~720 Nit peak white levels at power consumption levels which are ~133% those of WOLED (because of 4 layers versus 3).

The one reason for hope is I don’t understand how Samsung could brand a new OLED technology ‘Evo’ if it consumes 33% more power…

So the other read is that the June prototypes are based on phosphorescent blue that does not yet achieve the full lifetime Samsung would like.

Phosphorescent blue has an efficiency that is more tan 300% that if florescent blue, so in a heartbeat, a 20% peak white deficit turns into a +140% advantage (over 2100 Nits peak instead of 720 Nits peak).

But lifetime is only ~10% of what’s needed (at last report).

But if you limit peak brightness back down to 1/3 of what it could be, you’ve got the same 20% peak white deficit (back to 720 Nits peak), but now at 44% the power consumption of WOLED rather than 133% (and hence ‘Evo’).

That would still result in a lifetime that is only ~33% of what’s needed, but if Samsung Display has found further lifetime improvements of 3x or possibly even 2x, this dog could hunt…

The recent branding of Eco must mean that Samsung is planning on launching Phosogirescebt-blue-based QD-BOLED, and so the only question is whether they can deliver the lifetime Sony considers the minimum needed to Go To Market…
A few more tidbits on Samsung’s progress working to improve UDC’s deep blue PHOLED emitter can be found here: OLED Universal Display Corp Message Board - Msg: 33272927

Display Week 2021 includes the following invited paper:

27.1 - Invited Paper: Blue Phosphorescent Organic Light-Emitting Diodes for Future Displays Jinwon Sun, Changwoong Chu
Samsung Display, Co., Ltd. Yongin South Korea


The device lifetime of a blue phosphorescent OLED was extended more than tenfold over existing device architecture, further enhancing the improved chemical stability of a blue phosphorescent emitter. The authors' current work shows that blue phosphorescent OLED will become actively adopted in display products in the near future.’[/QUOTE]

More than 10-fold compared to what baseline is the $1000 question, but the same Author reported on a 5-fold improvement in 2020:

6.4 Late-News Paper: Realizing Deep Blue Emission in Blue Phosphorescent Organic Light- Emitting Diodes (12:10 PM - 12:30 PM)
Jinwon Sun, Hyein Jeong, Jaejin Lyu
Samsung Display, Co., Ltd. Yongin South Korea

The origin of spectrum broadening in blue phosphorescent organic light-emitting diodes (OLEDs) was investigated in order to improve color purity of the OLED device aiming to realize efficient blue phosphorescent OLED with deep blue emission. Assuming the formation of exciplex between host and guest (H-G) material from intermolecular charge transfer (CT) state of the two, the experiment was performed controlling the distance between H-G for the verification. The exciplex formation was observed dependent on the distance of H-G, indicating that the spectrum broadening occurred due to H-G CT state. The critical distance to avoid H-G CT state was found which can be further utilized in designing host and dopant materials for blue phosphorescent OLEDs. The efficiency and the stability of the blue phosphorescent device were enhanced by 1.2 and 5 times, respectively, by minimizing H-G CT state.’


And that 2020 report of 5-fold improvement appears to have included the following chart repeated by DSCC:

A4807B00-81F0-4626-A4F1-8528BF213874.png


So a 563.5% improvement reported in 2020 appears to now have further improved to ‘more than tenfold’ by this Spring - so pretty solid evidence that Samsung achieved a further ~doubling in UDC’s deep blue PHOLED lifetime over the past year.

OLED Info shows that UDC’s Light Blue PHOLED Emitter has an LT95 lifetime of 700 hours, so that’s probably an upper limit for the Deep Blue baseline Samsung was starting from:OLED Lifetime: introduction and market status | OLED-Info

And I found this table which could be from Cynora or Kyulux but probably provides a lower bound of 280 hours of Deep Blue LT95 Lifetime that Samsung probably started with:

896748A2-7264-4BA0-A2D8-20A6C78B4DBF.jpeg


So a realistic swag is that Samsung started with a Deep Blue PHOLED emitter from UDC delivered 280h to 700h of LT95 Lifetime, that they improved that by 563.5% by 2020 to 1580h to 4000 hours by 2022 and further improved in by ~2X to between 3000h and 8000h by this Spring.

I continue to believe the smart money is on another year of QD-BOLED delay, but at least I now understand why Samsung Visual Display wanted to be ready for a GO decision in September and invested some effort in getting OLED Eco branding teed-up in advance…

If we take the more likely lower end of that range but now use 4 layers to effectively quadruple blue lifetime (by reducing current to 1/4), we’re up to 12,000 hours to LT95, which starts getting within striking distance of the Florescent Blue Lifetime used by WOLED or the 14,000 hours delivered by UDC’s Deep Red PHOLED emitter used by WOLED…

Still a great deal of speculation but it’s looking to me that Samsung may be within a factor of 1.5 to 2 of where they need to be on Deep Blue PHOLED lifetime rather than another factor of 5-10…
 

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Solus’ HTL supply to LG for OLED is bad news for Merck
 
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