[HN Gopher] Tandem OLED is OLED's latest weapon in holding off M...
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Tandem OLED is OLED's latest weapon in holding off MicroLED, QDEL
Author : rbanffy
Score : 45 points
Date : 2024-09-24 10:23 UTC (3 days ago)
(HTM) web link (arstechnica.com)
(TXT) w3m dump (arstechnica.com)
| bluSCALE4 wrote:
| What's annoying is that this tech already existed for LCD
| screens. It supposedly had deep black that OLED brings but at LCD
| prices. If the quality is similar / no better, it's frustrating
| to see tandem tech never made it out of China.
| jsheard wrote:
| Those Hisense tandem LCDs had some significant issues that they
| weren't able to iron out, they had trouble with poor response
| times, ghosting, and color banding. Flanders Scientific also
| used to make tandem LCDs for ultra-high-end professional
| monitoring, which was a market that could tolerate high prices
| and poor power efficiency in the name of performance, but even
| they have migrated their HDR monitors over to QD-OLED now so I
| think the consensus is that tandem LCD is a dead end.
| kingsleyopara wrote:
| Dual-layer LCD is best thought of as a separate technology from
| tandem OLED, due to being transmissive rather than emissive. In
| many respects, it surpasses OLED, which is why mastering
| monitors used in Hollywood still employ this technology.
| Unfortunately, the poor efficiency and excessive energy
| consumption/heat output have hindered its adoption in the
| consumer market.
| jsheard wrote:
| > In many respects, it surpasses OLED, which is why mastering
| monitors used in Hollywood still employ this technology.
|
| Flanders Scientific were the main champions of dual LCDs in
| that market, and even they have phased out all of their dual
| LCD models in favor of QD-OLED ones now. I think they just
| brute force through OLEDs usual brightness limits by actively
| cooling the panel.
| rbanffy wrote:
| And speaking of high-brightness LED panels, I can swear I
| got a tan from one during a conference where the panel was
| sitting with the back towards the panel.
|
| Those things are hot and very bright.
| porphyra wrote:
| Dual LCDs also have poor brightness since a lot less light
| gets through the two layers. That can be overcome by a much
| stronger backlight, which produces tons of heat that
| require active cooling.
| kuschku wrote:
| Sony also makes dual-layer LCDs, they even introduced a new
| model in 2023:
| https://pro.sony/en_GB/products/broadcastpromonitors/bvm-
| hx3...
| jsheard wrote:
| Good to know, but that spec sheet neatly demonstrates the
| efficiency challenges of dual-layer LCD. That's a 31"
| panel which burns up to 610 watts!
| formerly_proven wrote:
| That's probably illegal to sell in the EU?
| wmf wrote:
| It's a professional reference monitor not a TV so maybe
| there's an exception.
| kuschku wrote:
| Those rules and regulations only apply to consumer
| products, business/professional products are exempt. This
| product is obviously not a consumer product.
| anamexis wrote:
| Also, it costs $25,000. But that might not be related to
| it being a dual-layer LCD, but rather other exacting
| tolerances for professional mastering use.
| fngjdflmdflg wrote:
| >It supposedly had deep black that OLED brings
|
| How does stacking displays let you get pixel level light
| emission of OLED or better blacks in general? The issue with
| LCD is that there is a display wide backlight so you have to
| actively block out the the backlight to make black. Even if
| there was some tech to stack something that added more blocking
| (I guess, adding another liquid crystal layer? Another
| polarizer? I admit to not really understanding the tech beyond
| a surface level, just trying to understand.), it doesn't seem
| to be the same tech as stacking OLEDs which is to get more
| brightness/less burnout. And if you mean stacking more light
| emission as in the case of OLED, that also wouldn't seem to
| contribute to better blacks.
| mapt wrote:
| Two LCDs, front to back, provide much better contrast by
| blocking more of the light in the liquid crystal layers.
|
| The rear one is greyscale.
|
| https://www.reddit.com/r/hardware/comments/w0u2rf/did_dual_l.
| ..
|
| https://www.rtings.com/tv/reviews/hisense/u9dg
| rbanffy wrote:
| OTOH, an LCD, at best, let's 50% of the light pass through
| it, so, for two stacked LCD panels, you'll need a much
| brighter backlight.
| toast0 wrote:
| LCDs work on polarization... you typically have an
| unpolarized source, run it through a polarized filter
| which is where your 50% loss comes from, then the LCD
| changes or doesn't the polarization, and you run it
| through a filter again. If you stacked a second LCD, you
| shouldn't see a second 50% loss, the light is already
| polarized by the first LCD.
| fngjdflmdflg wrote:
| >The rear one is grayscale.
|
| If I understand correctly, you're saying that there is a
| rear LCD that only either lets light in or blocks it
| without caring about the color? That's interesting. As for
| why they aren't investing in this then, it's might be at
| least in part due to the power usage which would make it
| unsuitable for battery powered devices such as the iPad
| mentioned in the article.
| Kirby64 wrote:
| Due to the way LCDs work it's never useful for a consumer
| monitor. The backlights needed to punch enough lumens through 2
| layers of LCD is prohibitively large/expensive, and the cooling
| needed to make sure you don't burn it out leads to a pretty
| thick and bulky design. Take a look at the professional
| monitors like this... there's a reason why they're so thick,
| and it's not because they're "industrial" or something. Also,
| power consumption is atrocious.
| rbanffy wrote:
| This sounds like a problem that PixelQi tech could solve - it
| used prisms instead of filters for colours, which reduced
| light absorption on inactive LCD pixels, so if the lower LCD
| is a PixelQi panel, you can add a set of filters with the
| second LCD panel and drive the backlight harder to gain
| better contrast (a problem with PixelQi) within the same
| power envelope of a "regular" LCD.
| tedunangst wrote:
| There's a diy perks video about making your own which goes into
| the pros and cons for the curious.
| cayleyh wrote:
| I thought MicroLED was not really ready to compete outside a TV-
| sized form factor due to the difficulty & costs to manufacture it
| at competitive resolution density for phones/tablets? Has that
| changed substantially since Apple cancelled it's MicroLED project
| for the Apple watch?
| porphyra wrote:
| yea it seems that microled is good at either being really big
| (110" TVs) or really small (VR headsets), but nothing in
| between yet.
| ivewonyoung wrote:
| > or really small (VR headsets)
|
| That's MicroOLED in the Apple Vision Pro, not MicroLED.
| Confusing, I know.
| porphyra wrote:
| I'm not talking about micro OLED. I'm talking about
| microled which is indeed made in small chips with VR and AR
| as the target market.
|
| For example the recently announced Meta Orion is said to
| use microled [1].
|
| At the recent microled connect conference there were lots
| of VR/AR focused talks [2].
|
| [1] https://www.microled-info.com/meta-announces-10000-ar-
| glasse...
|
| [2] https://www.microledconnect.com/current-agenda
| refulgentis wrote:
| Er, no.
|
| It's not shipping today for anything smaller than 8 foot
| TVs, and doesn't have a path.
|
| It's been 5 years away for at least a decade.
|
| OP is referencing Apple Watch cancellation because that
| was Apple throwing in the towel in microLED after a
| decade of investment, making it likely no one expects it
| to be solved soon.
|
| [1] Facebook is using a MicroLED _projector_ and
| expressly says the display is an unknown unknown, because
| they can 't ship this one if they wanted to. The failure
| rates are too high (see manufacturing process in [2]).
|
| [2] has been happening for at least 8 years. It'd be
| awesome for VR, but that's the least likely near term
| option because right now it boils down to "manually place
| 8,294,400 pixels and if any have errors, do it again."
| Its shipping at eye-watering prices in Samsung TVs > 100"
| (read: have "huge" pixel sizes so they can be manually
| placed)
| throwaway48476 wrote:
| They're still doing pick and place with millions of individual
| LEDs.
| siffin wrote:
| All I have to say is that the tandem oled on my ipad pro still,
| everytime I use it, makes me wow. It is an absolute pleasure to
| look at and watch things on. It feels like I'm watching real life
| and I love it.
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