7 ms·

Mini-LED, Micro-LED and OLED displays: present status and future perspectives

66 points by zeristor 6y ago

gtm1260 6y ago
Very excited for the new display technologies on the horizon. Sure, current Tv's and Monitors are pretty good, but I can't wait to see the picture quality that we're going to get. Linus Tech Tips has a pretty easy to understand video (much higher level though) on this stuff. He goes into the manufacturer roadmap which I think is pretty good to know in terms of the time horizon for these technologies. https://www.youtube.com/watch?v=RTTiQeXXrhI https://www.youtube.com/watch?v=RTTiQeXXrhI
- spuz 6y ago
  Thanks, that was an excellent video.
muska3 6y ago
Very interesting. One thing I don't fully understand is the difference between mLED and uLED. As I understand, mLED have a an array of separately controllable backlights, but what exactly is uLED?
- branko_d 6y ago
  The pixels are self-emitting (similar to OLED).
- xt00 6y ago
  miniLED means that they place small LED's that are basically equivalent to the present level of LED technology behind an LCD array. So instead of the normal LCD backlight design where you shoot LED light sideways from the LCD module edge into a series of films that direct the light from the sideways direction to the normal viewing axis direction, the LED's are placed in a regular grid behind the LCD array itself, but you need a large number of these mini LED's to cover the entire surface of the display panel, as well as some diffusers to reduce hotspots. The main advantage is that the peak brightness you could get using this technique could be quite high. And in a sense you can get high contrast ratios by selectively dimming certain zones. So comparing two zones the contrast can be quite high, but comparing within a zone the contrast ratio is still the same as a normal LCD. uLED means that you are attempting to place one LED chip for every pixel. Equivalent to how they build those large LED signs at sports arenas. In the smart phone situation, the LED chips would need to be crazy small -- on the order of say 10-50 microns -- so the name uLED (microLED) makes sense.
  - zokier 6y ago
    FALD has been a thing long since before mled was spun up. As far as I can tell, mled is just a marketing term for slightly higher number of dimming zones.
    - nitrogen 6y ago
      If the number of dimming zones approaches the number of pixels, that could make a pretty big difference.
      - zokier 6y ago
        Approaches, but very slowly. Jumping from 1000 zones to 10000 zones might seem impressive, but it is still pretty far cry from 8+ million pixels of a typical 4k screen.
    - TheAdamist 6y ago
      Mini led is supposed to be quite a lot higher number of zones, but it looks like the controllers / algorithms aren't ready yet. Regular FALD tvs generally have 16-800 zones. The tcl 8 series tv is the only miniled one i know of, and has 25000 minileds. Unfortunately they are grouped such that there are only about 900 zones, which is very disappointing. Hopefully the next generation of miniled will deliver the hype.
- deleted 6y ago
  [deleted]
xt00 6y ago
One problem I see with microLED's taking off is that the primary parameter the microLED design helps with is power for a given brightness. If the uLED tech costs more than a normal smartphone display (seems to be likely to be true for some time) then getting improved power efficiency I'm not sure would cause a big wave of adoption similar to what has happened with OLED over the past 3-4 years. OLED compared to LCD tends to have both better color gamut and contrast ratio, and when using dark mode UI's the power savings can be pretty high. Hard to see how uLED would be able to differentiate itself from OLED except for showing HDR images in a power efficient way. I'm probably missing something else about why uLED is good though?
- baybal2 6y ago
  > I'm probably missing something else about why uLED is good though? The fancy VR/AR goggles category. It's pretty much the one, and only way to make battery powered goggles usable outdoors. The one who gets there first with patents wins the game.
  - corey_moncure 6y ago
    Also the "doesn't degrade/burn-in/shift whitepoint after a year of ordinary use" category.
    - s9w 6y ago
      This is the main concern I think. It's what's always being brought up with OLEDs.
- ksec 6y ago
  Yes and OLED has a decent roadmap of Cost Reduction in the next 3- 5 years along with other quality improvements. So I dont think uLED would replace them on Smartphone. Not to mention the possibility of screen without the cover glass. So your smartphone with reduction in weight, does not break the panel when fall, and thinner. But for Desktop applications and VR Glasses uLED will have an advantage with no burn in issues. I do sometimes wonder if WOLED could scale down to those needs. But I dont see any intention of LG going down that path. Correct me if I am wrong.
baybal2 6y ago
One elephant in the room that wasn't mentioned: Samsung is years ahead of anybody with self emissive quantum dots, and new types of TFT matrices. Samsung can commercialise cheap self emissive qdots within 2-3 years if they want, and then microleds will be automatically obsolete, probably with exception of displays for VR goggles. Samsung has another ace in the sleeve they don't get public about: they know a trick how to grow GaN leds on amorphous substrates. Their papers from 2012 showed them being in a quite advanced stage already. If they can get advanced with the later, they can not only bust the display market, but pretty much everything LED. If LEDs can be grown on a much cheaper, and less finicky substrate than sapphire, we can talk about them getting n-times cheaper.
- Exmoor 6y ago
  Link? > Samsung can commercialise cheap self emissive qdots within 2-3 years if they want Fantastic if true, but I'll believe it when I purchase one for a price competitive with similarly performing technologies. I've seen enough promised display technologies that were "2-3 years away" to be very skeptical.
  - baybal2 6y ago
    https://www.sci-hub.tw/10.1038/nphoton.2011.253 https://www.sci-hub.tw/10.1038/nphoton.2011.253 https://www.sait.samsung.com/saithome/mobile/about/press_view.do?new_seq=1032 https://www.sait.samsung.com/saithome/mobile/about/press_vie... https://www.sci-hub.tw/10.1016/j.apmt.2019.100541 https://www.sci-hub.tw/10.1016/j.apmt.2019.100541
- gruez 6y ago
  So if samsung is so ahead, why aren't we seeing it in present displays? Is it because it's too expensive? Or are they hoarding it for a rainy day?
  - baybal2 6y ago
    > Or are they hoarding it for a rainy day? Very much it, that's how "big semi" operated through the years. R&D offices produce motherlodes worth of research for directors to pick depending on market situation on the moment notice.
Sloppy 6y ago
This report doesn't seem to mention burn-in directly. This is IMHO the achilles heel of the current crop of OLED TVs. This is a very hidden fact. Everyone talks about how great they are and say they're the hands-down winner among popular TVs but after having owned one for 2 years it displayed horrible burn-in. They are fantastic while they last then they are awful. It would be nice to know how mLeds, uLeds, and the new tech sizes up for burn-in.
- fabian2k 6y ago
  Whether burn-in is still an issue depends very heavily on how you use the OLED TV. I have my OLED TV for almost three years and no burn-in. I know there are tests that show that you can provoke burn-in, but that is with rather extreme scenarios. If you don't have static elements on for hours at a time, you generally shouldn't have an issue. One thing I've heard, but that doesn't apply to my usage is that e.g. putting on TV stations with static chyrons in bold colors can lead to burn-in.
  - CuriousSkeptic 6y ago
    I first noticed the yellow button from the youtube app burnt in (after about three years). Then it was a smear of green in the middle probably from all the yellow highlighting of objects in the witcher(Xbox game). Also some lines from subtitles are starting to show, and lately I’ve been able to read Netflix written in the lower right corner. It seems there are some ui-patterns involved that could perhaps, at least for the webos apps, be avoided through interface standards.
  - SloopJon 6y ago
    Here is one of those tests: https://www.rtings.com/tv/learn/real-life-oled-burn-in-test https://www.rtings.com/tv/learn/real-life-oled-burn-in-test Is it extreme? Sure, but it's not contrived--five hours on, one hour off. If the TV in the office break room was an OLED, it would absolutely exhibit this level of burn in.
- Shivetya 6y ago
  Seriously it is not. I have a LG C9 and bought it after recommendation from friends who game on theirs. If you are going to leave it on the same screen all day long there are better choices, like having it on a new station that has a permanent ticker or channels which insist on a permanent logo. You have to go out of your way to force burn in, there has been some good 3rd party testing [0] Oh, as for the TV, the colors are astounding and its thinness is just a bit on the silly side, seriously from one third on up from the base it is as thick as iPad I expect micro LED to over take it one day but for now if you are a movie aficionado there is no subsistute, this is especially true when dealing with letter boxed movies as there is no bleed into the black borders [0] https://www.rtings.com/tv/learn/real-life-oled-burn-in-test https://www.rtings.com/tv/learn/real-life-oled-burn-in-test
rado 6y ago
Please already replace the LED LCD of the last 20 years, whose backlight bleed is ridiculously bad.
fabian2k 6y ago
I'm somewhat disappointed in the lack of progress on OLEDs the last few years. For TVs, LG is the only company that actually produces panels, every single OLED TV uses their panels. And even though there are new models every year, all OLED TVs of the last few years use the same old panel.
- ksec 6y ago
  That is not true at all. While LG is the only OLED TV panel manufacture on the market, they have been making progress every year in their WOLED panel. And many more technical innovations in the pipeline. And older panel drop in price as they improve yield, that is why you start seeing affordable OLED. They differ in colour accuracy, refresh rate, QA, max brightness etc. To say they are the same panel every year give very little credit to LG's WOLED engineering.
  - fabian2k 6y ago
    My information is from various reviews, and the image quality has stayed pretty much the same the last three years according to that. The image processing has changed, but the panels seem to be pretty much the same within the differences you get per-panel anyway.
  - zmarty 6y ago
    Max brightness progress is marginal at best for the past 4-5 years.
    - ksec 6y ago
      Because that is at the expense of the panel's longevity that most people not prefer as a trade offs?
    - darkteflon 6y ago
      I’ve never looked at my C9 and thought “I wish it was brighter”. Does seem to bother some people though so YMMV.
- brokenmachine 6y ago
muska3 6y ago
One major question I have: how come we haven't seen any innovations to desktop monitors? Most of the innovations come first to TV's and smartphone displays. It seems like the pace of desktop monitor innovation is slower.
- saagarjha 6y ago
  Smaller market?
- JulianMorrison 6y ago
  My guess is that most desktop monitor buyers are very price sensitive and largely quality insensitive.
- njharman 6y ago
  Total PC 2019 255.7 Mobile Phone 2019 1,743.10 and is 4k, higher refresh rates, curved displays, ultra ultra wide, very very thin (comparying my new to old monitor, and less energy usage; not innovations?
- stubish 6y ago
  I'm more interested in why TVs and monitors are considered separate markets. The difference between a TV and a monitor is software, and maybe a display port input for the highest resolutions or refresh rates. This large TV I use as a monitor is great, apart from lack of suspend and an annoying banner that pops up every time the resolution or audio inputs change. And much cheaper, assuming I could find a 43" 4k computer display at all in my region.
  - darkteflon 6y ago
    Spot on. I switched to a 40” 4k Phillips VA panel (BDM4065) a few years back and can’t imagine switching back to anything smaller. Quite cheap, too. Might not be suitable for colour-sensitive work but perfectly serviceable for VS Code and a browser.
sroussey 6y ago
Why not sandwich two LCDs together — one B&W lower resolution, and then the 4K color one? Align them so one B&W pixel switches for the three sub pixels of RGB.
- randyrand 6y ago
  People want HDR. hard to make a brighter display by removing more light.
  - TheAdamist 6y ago
    They also want better black levels that oled provides. Its relatively easy to get lcds bright, but then the black level suffers. But yeah, ive read these dual layer lcds are horribly inefficient power wise.
    - dungdang 6y ago
      how do you get blacker than 'no light emitted' when the oled pixel is off? in other words, how does a light bulb in your desk lamp produce less light than zero?
- phonypc 6y ago
  These exist, called dual-layer LCD. IIRC mostly reserved for professional applications, with some consumer stuff on the horizon.
- TheAdamist 6y ago
  Hi-sense has one coming to market. Dual layer lcd. Ive read somewhere that i cant find currently that due to the second layer its much worse energy efficiency wise than current backlit tvs and may fail energy standards from various organizations and may not be able to be sold. (EU maybe). Oled is coming down in price though, itll be interesting to see if its price competitive. https://www.cnet.com/news/look-out-oled-hisense-unveils-dual-lcd-tv-tech-aimed-at-lower-price/ https://www.cnet.com/news/look-out-oled-hisense-unveils-dual... Great idea, but i dont think id buy first gen.

66 points by zeristor 6y ago

Very excited for the new display technologies on the horizon. Sure, current Tv's and Monitors are pretty good, but I can't wait to see the picture quality that we're going to get. Linus Tech Tips has a pretty easy to understand video (much higher level though) on this stuff. He goes into the manufacturer roadmap which I think is pretty good to know in terms of the time horizon for these technologies. https://www.youtube.com/watch?v=RTTiQeXXrhI https://www.youtube.com/watch?v=RTTiQeXXrhI

spuz 6y ago
Thanks, that was an excellent video.

muska3 6y ago

Very interesting. One thing I don't fully understand is the difference between mLED and uLED. As I understand, mLED have a an array of separately controllable backlights, but what exactly is uLED?

branko_d 6y ago
The pixels are self-emitting (similar to OLED).
xt00 6y ago
miniLED means that they place small LED's that are basically equivalent to the present level of LED technology behind an LCD array. So instead of the normal LCD backlight design where you shoot LED light sideways from the LCD module edge into a series of films that direct the light from the sideways direction to the normal viewing axis direction, the LED's are placed in a regular grid behind the LCD array itself, but you need a large number of these mini LED's to cover the entire surface of the display panel, as well as some diffusers to reduce hotspots. The main advantage is that the peak brightness you could get using this technique could be quite high. And in a sense you can get high contrast ratios by selectively dimming certain zones. So comparing two zones the contrast can be quite high, but comparing within a zone the contrast ratio is still the same as a normal LCD. uLED means that you are attempting to place one LED chip for every pixel. Equivalent to how they build those large LED signs at sports arenas. In the smart phone situation, the LED chips would need to be crazy small -- on the order of say 10-50 microns -- so the name uLED (microLED) makes sense.
- zokier 6y ago
  FALD has been a thing long since before mled was spun up. As far as I can tell, mled is just a marketing term for slightly higher number of dimming zones.
  - nitrogen 6y ago
    If the number of dimming zones approaches the number of pixels, that could make a pretty big difference.
    - zokier 6y ago
      Approaches, but very slowly. Jumping from 1000 zones to 10000 zones might seem impressive, but it is still pretty far cry from 8+ million pixels of a typical 4k screen.
  - TheAdamist 6y ago
    Mini led is supposed to be quite a lot higher number of zones, but it looks like the controllers / algorithms aren't ready yet. Regular FALD tvs generally have 16-800 zones. The tcl 8 series tv is the only miniled one i know of, and has 25000 minileds. Unfortunately they are grouped such that there are only about 900 zones, which is very disappointing. Hopefully the next generation of miniled will deliver the hype.
deleted 6y ago
[deleted]

xt00 6y ago

One problem I see with microLED's taking off is that the primary parameter the microLED design helps with is power for a given brightness. If the uLED tech costs more than a normal smartphone display (seems to be likely to be true for some time) then getting improved power efficiency I'm not sure would cause a big wave of adoption similar to what has happened with OLED over the past 3-4 years. OLED compared to LCD tends to have both better color gamut and contrast ratio, and when using dark mode UI's the power savings can be pretty high. Hard to see how uLED would be able to differentiate itself from OLED except for showing HDR images in a power efficient way. I'm probably missing something else about why uLED is good though?

baybal2 6y ago
> I'm probably missing something else about why uLED is good though? The fancy VR/AR goggles category. It's pretty much the one, and only way to make battery powered goggles usable outdoors. The one who gets there first with patents wins the game.
- corey_moncure 6y ago
  Also the "doesn't degrade/burn-in/shift whitepoint after a year of ordinary use" category.
  - s9w 6y ago
    This is the main concern I think. It's what's always being brought up with OLEDs.
ksec 6y ago
Yes and OLED has a decent roadmap of Cost Reduction in the next 3- 5 years along with other quality improvements. So I dont think uLED would replace them on Smartphone. Not to mention the possibility of screen without the cover glass. So your smartphone with reduction in weight, does not break the panel when fall, and thinner. But for Desktop applications and VR Glasses uLED will have an advantage with no burn in issues. I do sometimes wonder if WOLED could scale down to those needs. But I dont see any intention of LG going down that path. Correct me if I am wrong.

baybal2 6y ago

One elephant in the room that wasn't mentioned: Samsung is years ahead of anybody with self emissive quantum dots, and new types of TFT matrices. Samsung can commercialise cheap self emissive qdots within 2-3 years if they want, and then microleds will be automatically obsolete, probably with exception of displays for VR goggles. Samsung has another ace in the sleeve they don't get public about: they know a trick how to grow GaN leds on amorphous substrates. Their papers from 2012 showed them being in a quite advanced stage already. If they can get advanced with the later, they can not only bust the display market, but pretty much everything LED. If LEDs can be grown on a much cheaper, and less finicky substrate than sapphire, we can talk about them getting n-times cheaper.

Exmoor 6y ago
Link? > Samsung can commercialise cheap self emissive qdots within 2-3 years if they want Fantastic if true, but I'll believe it when I purchase one for a price competitive with similarly performing technologies. I've seen enough promised display technologies that were "2-3 years away" to be very skeptical.
- baybal2 6y ago
  https://www.sci-hub.tw/10.1038/nphoton.2011.253 https://www.sci-hub.tw/10.1038/nphoton.2011.253 https://www.sait.samsung.com/saithome/mobile/about/press_view.do?new_seq=1032 https://www.sait.samsung.com/saithome/mobile/about/press_vie... https://www.sci-hub.tw/10.1016/j.apmt.2019.100541 https://www.sci-hub.tw/10.1016/j.apmt.2019.100541
gruez 6y ago
So if samsung is so ahead, why aren't we seeing it in present displays? Is it because it's too expensive? Or are they hoarding it for a rainy day?
- baybal2 6y ago
  > Or are they hoarding it for a rainy day? Very much it, that's how "big semi" operated through the years. R&D offices produce motherlodes worth of research for directors to pick depending on market situation on the moment notice.

Sloppy 6y ago

This report doesn't seem to mention burn-in directly. This is IMHO the achilles heel of the current crop of OLED TVs. This is a very hidden fact. Everyone talks about how great they are and say they're the hands-down winner among popular TVs but after having owned one for 2 years it displayed horrible burn-in. They are fantastic while they last then they are awful. It would be nice to know how mLeds, uLeds, and the new tech sizes up for burn-in.

fabian2k 6y ago
Whether burn-in is still an issue depends very heavily on how you use the OLED TV. I have my OLED TV for almost three years and no burn-in. I know there are tests that show that you can provoke burn-in, but that is with rather extreme scenarios. If you don't have static elements on for hours at a time, you generally shouldn't have an issue. One thing I've heard, but that doesn't apply to my usage is that e.g. putting on TV stations with static chyrons in bold colors can lead to burn-in.
- CuriousSkeptic 6y ago
  I first noticed the yellow button from the youtube app burnt in (after about three years). Then it was a smear of green in the middle probably from all the yellow highlighting of objects in the witcher(Xbox game). Also some lines from subtitles are starting to show, and lately I’ve been able to read Netflix written in the lower right corner. It seems there are some ui-patterns involved that could perhaps, at least for the webos apps, be avoided through interface standards.
- SloopJon 6y ago
  Here is one of those tests: https://www.rtings.com/tv/learn/real-life-oled-burn-in-test https://www.rtings.com/tv/learn/real-life-oled-burn-in-test Is it extreme? Sure, but it's not contrived--five hours on, one hour off. If the TV in the office break room was an OLED, it would absolutely exhibit this level of burn in.
Shivetya 6y ago
Seriously it is not. I have a LG C9 and bought it after recommendation from friends who game on theirs. If you are going to leave it on the same screen all day long there are better choices, like having it on a new station that has a permanent ticker or channels which insist on a permanent logo. You have to go out of your way to force burn in, there has been some good 3rd party testing [0] Oh, as for the TV, the colors are astounding and its thinness is just a bit on the silly side, seriously from one third on up from the base it is as thick as iPad I expect micro LED to over take it one day but for now if you are a movie aficionado there is no subsistute, this is especially true when dealing with letter boxed movies as there is no bleed into the black borders [0] https://www.rtings.com/tv/learn/real-life-oled-burn-in-test https://www.rtings.com/tv/learn/real-life-oled-burn-in-test

rado 6y ago

Please already replace the LED LCD of the last 20 years, whose backlight bleed is ridiculously bad.

fabian2k 6y ago

I'm somewhat disappointed in the lack of progress on OLEDs the last few years. For TVs, LG is the only company that actually produces panels, every single OLED TV uses their panels. And even though there are new models every year, all OLED TVs of the last few years use the same old panel.

ksec 6y ago
That is not true at all. While LG is the only OLED TV panel manufacture on the market, they have been making progress every year in their WOLED panel. And many more technical innovations in the pipeline. And older panel drop in price as they improve yield, that is why you start seeing affordable OLED. They differ in colour accuracy, refresh rate, QA, max brightness etc. To say they are the same panel every year give very little credit to LG's WOLED engineering.
- fabian2k 6y ago
  My information is from various reviews, and the image quality has stayed pretty much the same the last three years according to that. The image processing has changed, but the panels seem to be pretty much the same within the differences you get per-panel anyway.
- zmarty 6y ago
  Max brightness progress is marginal at best for the past 4-5 years.
  - ksec 6y ago
    Because that is at the expense of the panel's longevity that most people not prefer as a trade offs?
  - darkteflon 6y ago
    I’ve never looked at my C9 and thought “I wish it was brighter”. Does seem to bother some people though so YMMV.
brokenmachine 6y ago

muska3 6y ago

One major question I have: how come we haven't seen any innovations to desktop monitors? Most of the innovations come first to TV's and smartphone displays. It seems like the pace of desktop monitor innovation is slower.

saagarjha 6y ago
Smaller market?
JulianMorrison 6y ago
My guess is that most desktop monitor buyers are very price sensitive and largely quality insensitive.
njharman 6y ago
Total PC 2019 255.7 Mobile Phone 2019 1,743.10 and is 4k, higher refresh rates, curved displays, ultra ultra wide, very very thin (comparying my new to old monitor, and less energy usage; not innovations?
stubish 6y ago
I'm more interested in why TVs and monitors are considered separate markets. The difference between a TV and a monitor is software, and maybe a display port input for the highest resolutions or refresh rates. This large TV I use as a monitor is great, apart from lack of suspend and an annoying banner that pops up every time the resolution or audio inputs change. And much cheaper, assuming I could find a 43" 4k computer display at all in my region.
- darkteflon 6y ago
  Spot on. I switched to a 40” 4k Phillips VA panel (BDM4065) a few years back and can’t imagine switching back to anything smaller. Quite cheap, too. Might not be suitable for colour-sensitive work but perfectly serviceable for VS Code and a browser.

sroussey 6y ago

Why not sandwich two LCDs together — one B&W lower resolution, and then the 4K color one? Align them so one B&W pixel switches for the three sub pixels of RGB.

randyrand 6y ago
People want HDR. hard to make a brighter display by removing more light.
- TheAdamist 6y ago
  They also want better black levels that oled provides. Its relatively easy to get lcds bright, but then the black level suffers. But yeah, ive read these dual layer lcds are horribly inefficient power wise.
  - dungdang 6y ago
    how do you get blacker than 'no light emitted' when the oled pixel is off? in other words, how does a light bulb in your desk lamp produce less light than zero?
phonypc 6y ago
These exist, called dual-layer LCD. IIRC mostly reserved for professional applications, with some consumer stuff on the horizon.
TheAdamist 6y ago
Hi-sense has one coming to market. Dual layer lcd. Ive read somewhere that i cant find currently that due to the second layer its much worse energy efficiency wise than current backlit tvs and may fail energy standards from various organizations and may not be able to be sold. (EU maybe). Oled is coming down in price though, itll be interesting to see if its price competitive. https://www.cnet.com/news/look-out-oled-hisense-unveils-dual-lcd-tv-tech-aimed-at-lower-price/ https://www.cnet.com/news/look-out-oled-hisense-unveils-dual... Great idea, but i dont think id buy first gen.