Quick OLED Summary

M

MrWTF

Guest
I've been watching the progression of (Polymer) Organic Light Emitting Diodes (P)OLED (previously called LEP - light emitting polymers) since around 2001. I thought I'd share some of the information I've absorbed over this time as a followup to the FAQ sticky. Please feel free to offer corrections as appropriate.

The core of the technology is the concept using polymers which glow red, green or blue when electricity is passed through them.

This has the following advantages:
  • the polymers can be a liquid and therefore inkjet printing of a screen is possible
  • because they are self illuminating there is no requirement for a traditional backlight
  • screens can be paper thin, roll up etc.
  • power consumption based purely on scene intensity = lower power consumption over LCD/Plasma
  • vastly improved black contrast over LCD/Plasma
  • vastly cheaper to mass produce large screens
  • potential to be applied to any surface
The main constraint on P-OLED is the lifetime of each colour. The colours degrade as electricity is passed through them as follows:
  • The fastest to decompose is blue (62,000 hrs)
  • then red (420,000hrs)
  • finally green (445,000hrs)
More intensity results in faster degradation - these values are based on 400cd/m^2 which is roughly the intensity of a traditional LCD TV.

The main leader in the technology appears to have been Cambridge Display Technology (CDT). They have achieved 62,000 hours of blue lifetime at 400cd/m^2.

CDT were purchased by Sumitomo corporation in 2007 which seems to imply that their technology was superior to their main competitor Universal Display Corporation.

P-OLEDs are already in use in many small devices with short lifetimes such as mobile phones, electric razors and small LED displays.

CDT has also discovered that when light shines on P-OLEDs electricity is produced. This means OLEDs in reverse can act as efficient solar cells and will be vastly cheaper to produce than traditional solar cells. What this means is cheap self powered displays on everyday items like food packaging could soon be possible.

Working proof of concept prototypes have been produced, including this 40inch OLED TV by Epson in 2004.
 

NicolasB

Distinguished Member
You might like to add some details about which companies have promised to deliver what type of OLED device and when....
 

KyoDash

Novice Member
Are these displays fixed pixel like LCD or Plasma, or are they capable of doing multiple resolutions without scaling (like CRT)?
 

KyoDash

Novice Member
What a shame, we've just taken the biggest leap backwards in 40 years with display technology.:thumbsdow

Upscaling will ever match native resolutions, we haven't got anywhere near the processing power to do it in real time 60 frames per second.
 

NoDad

Novice Member
.......
  • The fastest to decompose is blue (62,000 hrs)
  • then red (420,000hrs)
  • finally green (445,000hrs)
I presume these are the times to half brightness?

If the output degradation is know, it could be automatically compensated for but I accept that increasing the current to compensate for the drop off in brightness will only cause the brightness to degrade even faster.

If the blue could be sorted out, the potential is tremendous. On the other hand, if the display can be "printed", why not recycle it, because the cost should be very low. It also seems that these displays could be screen printed with precision stainless steel screens (as used for printed circuit board solder paste deposition).

Things are certainly getting very interesting on a number of fronts. I personally can see me changing TVs several times in the next 10 years. :D:laugh:
 

NoDad

Novice Member
........Upscaling will ever match native resolutions, we haven't got anywhere near the processing power to do it in real time 60 frames per second.
I don't agree with this. A good upscaler will produce a far superior picture on a large screen to a large screen with big pixels. On a small screen, native resolution will always look better but the whole point is that screens are getting bigger.

Can you imagine 720 x 576 pixels on a 52" display. The steps in diagonal lines and lines just off the horizontal would look terrible. A good scaler will smooth these steps out over several pixels, producing a far better picture.

As for processing power, I do agree to some extent but processors and dedicated asics are getting faster every day. Things will get better and better for less and less notes.
 

KyoDash

Novice Member
Can you imagine 720 x 576 pixels on a 52" display. The steps in diagonal lines and lines just off the horizontal would look terrible. A good scaler will smooth these steps out over several pixels, producing a far better picture.
Not true for all displays. There are 60" CRT projection arcade monitors which suffer practically no pixelation or noticeable scan lines at that res, though can be slighly blurry if not set up right.

See some of the ones Sega use in Ghost Squad and Outrun2SP

The average person though does not have room for a 'large screen' TV, with most buying between 26" and 32". For the home user and especially gamers, a multi res capable display would be best.

I've yet to see upscaling match a resolution being displayed natively, and that being on a small 26" screen. The upscaling just made things look blurrier than before, lacking shapness and clarity overall, especially on text, counters and fine details etc.

As for processing power, I do agree to some extent but processors and dedicated asics are getting faster every day. Things will get better and better for less and less notes.
I agree, but how long is it going to take for scaling to match a resolution being displayed natively. I don't want to spend twenty years of my life waiting for a TV to be able to 480p decently again.

In my opinion fixed pixel tech is completely the wrong way to go, and in a few years they could have a CRT that is only 3" deep, and multi-sync. A flat display which doesn't remove features for the sake of style.

The current situation is both dipressing and completely avoidable.
 

NoDad

Novice Member
KyoDash, don't forget that CRTs have fixed pixel pitch (in fact on wide screen CRTs they are not even that - if you look at the pixel stripes on a widescreen CRT they get bigger as you move away from the centre of the screen). For computer CRTs the dot pitch is fixed on CRTs. The "analogue" scanning which produces the picture overlays the actual pixel size on top of this fixed pixel pitch, which can mean that 1.5 pixels on the screen are used for 1 pixel of information.
Compound this with anamorphic 16:9, where 720 x 576 pixels are stretched horizontally, resulting in rectangular pixels and you begin to see what a compromise CRT is. At least with 1920 x 1080 you are getting exact pixel mapping of the picture data to the display.
When a 1080 native display is used to display a 720 x 576 signal, the lower resolution pixel detail is (in crude terms) stretched over several pixels, to fill the screen, as with a CRT. What scalers do, which CRTs do not do, is analyse adjacent pixels to provide smoother transitions between what would be big pixel steps.
If you want the same "multi resolution" effect as a CRT, the way to do it would be to have many more pixels on the screen than were needed, so that the same crude scanning technique could be applied. I can't see any display manufacturer doing this because it would cost a fortune and be moving away from 1:1 pixel mapping.
 

juLZ007

Novice Member
how would my 25" 10+ year old sony crt handle hd tv? or is that not possible?

for example when analogue gets switched off in 2012 (in london), will it be possible to watch hi def tv as a broadcast through an analogue tv?
 

LV426

Administrator
Staff member
how would my 25" 10+ year old sony crt handle hd tv? or is that not possible?

for example when analogue gets switched off in 2012 (in london), will it be possible to watch hi def tv as a broadcast through an analogue tv?
Way, way off topic!

Short answer: it won't.
Longer answer: it won't need to. At least in the medium term, all broadcasts will be available as, or boxes will be able to convert to, standard PAL TV resolutions, for use by people with TVs such as yours.

(Please continue THIS subject in, say, the CRT TV forum, thanks).
 

kiran_mk2

Member
I've been watching the progression of (Polymer) Organic Light Emitting Diodes (P)OLED (previously called LEP - light emitting polymers) since around 2001. I thought I'd share some of the information I've absorbed over this time as a followup to the FAQ sticky. Please feel free to offer corrections as appropriate.

The core of the technology is the concept using polymers which glow red, green or blue when electricity is passed through them.

This has the following advantages:
  • the polymers can be a liquid and therefore inkjet printing of a screen is possible
  • because they are self illuminating there is no requirement for a traditional backlight
  • screens can be paper thin, roll up etc.
  • power consumption based purely on scene intensity = lower power consumption over LCD/Plasma
  • vastly improved black contrast over LCD/Plasma
  • vastly cheaper to mass produce large screens
  • potential to be applied to any surface
The main constraint on P-OLED is the lifetime of each colour. The colours degrade as electricity is passed through them as follows:
  • The fastest to decompose is blue (62,000 hrs)
  • then red (420,000hrs)
  • finally green (445,000hrs)
More intensity results in faster degradation - these values are based on 400cd/m^2 which is roughly the intensity of a traditional LCD TV.

The main leader in the technology appears to have been Cambridge Display Technology (CDT). They have achieved 62,000 hours of blue lifetime at 400cd/m^2.

CDT were purchased by Sumitomo corporation in 2007 which seems to imply that their technology was superior to their main competitor Universal Display Corporation.

P-OLEDs are already in use in many small devices with short lifetimes such as mobile phones, electric razors and small LED displays.

CDT has also discovered that when light shines on P-OLEDs electricity is produced. This means OLEDs in reverse can act as efficient solar cells and will be vastly cheaper to produce than traditional solar cells. What this means is cheap self powered displays on everyday items like food packaging could soon be possible.

Working proof of concept prototypes have been produced, including this 40inch OLED TV by Epson in 2004.
I work in conjunction with Sumation UK (the joint venture between CDT and Sumitomo) on white PLEDs for lighting so I know what's going on in the industry. The reason Sumitomo bought out CDT was because a few years ago Sumitomo bought out the LEP technology from Dow and therefore it made sense to go with CDT rather than UDC or Philips who are working on small molecule emitters. In terms of performance, small molecules are destroying the polymers in terms of performance. The German firm Novaled have got devices lasting over 1,000,000 hours at 1000cd/m^2. However, whilst the materials are just about ready for production, the engineering techniques aren't. The reason the small-molecule emitters are so good is that the devices contain lots of different layers all of which have to be evaporated at 1 millionth atmospheric pressure and high temperatures which isn't cheap. This is why the performance is there but there is no availability beyond small screens for phones etc. The advantage of LEPs is they can be "wet-processed" through techniques such as gravure printing and inkjet. This is a lot cheaper to do but the technology isn't quite there yet. If you think LCDs were invented in the 70s but it wasn't until a few years ago that they could be reliably and cheaply made so it's taken about 30 years. OLEDs have been around for 20 years so don't expect that 40" anytime before 2010 at the very earliest.
 

Spiderkid

Active Member
Fascinating concept. Does this mean that in a few years time (ok, maybe 5+) we could see TV's being produced almost like wallpaper? So you flat screen TV really could be flat against a wall (or even on your ceiling as I assume they're a lot lighter), and almost any size?

As for advances in technology, as little as 5 years ago you could pay up to £5000 for a portable 7" lcd DVD player, now they give them away!
 

kiran_mk2

Member
There are several components - the encasing, the OLED and the electronics. At the moment the electronics are still based on traditional rigid silicon, but organic (ie plastic) TFTs are coming (http://www.youtube.com/watch?v=rYc4dnVs4RM) which will permit flexy displays. Then you'd have to hope we've gone to wireless HDMI and wireless power too.
 

Tatra-Man

Active Member
Are these displays fixed pixel like LCD or Plasma, or are they capable of doing multiple resolutions without scaling (like CRT)?
Fixed pixel. Everything is and forever will be fixed-pixel apart from CRT.
even SED or FED? or laser tv for that matter
Not true.:nono: Various projection methods can have no pixel patterning and be truly analogue such as the Eidophor, anything similar using the Schlieren effect, anything using separate primary displays (such as three CRTs) and anything using optical scanning (via rotating, oscillating or deforming prisms, mirrors, lenses etc.) with a modulated light source.:lesson:

KyoDash, don't forget that CRTs have fixed pixel pitch (in fact on wide screen CRTs they are not even that - if you look at the pixel stripes on a widescreen CRT they get bigger as you move away from the centre of the screen). For computer CRTs the dot pitch is fixed on CRTs. The "analogue" scanning which produces the picture overlays the actual pixel size on top of this fixed pixel pitch, which can mean that 1.5 pixels on the screen are used for 1 pixel of information.
Compound this with anamorphic 16:9, where 720 x 576 pixels are stretched horizontally, resulting in rectangular pixels and you begin to see what a compromise CRT is.
Not true.:nono: What you say only applies to single tube displays, not optically combined displays from three separate CRTs.
 

onkeh

Novice Member
Not true for all displays. There are 60" CRT projection arcade monitors which suffer practically no pixelation or noticeable scan lines at that res, though can be slighly blurry if not set up right.

See some of the ones Sega use in Ghost Squad and Outrun2SP

The average person though does not have room for a 'large screen' TV, with most buying between 26" and 32". For the home user and especially gamers, a multi res capable display would be best.

I've yet to see upscaling match a resolution being displayed natively, and that being on a small 26" screen. The upscaling just made things look blurrier than before, lacking shapness and clarity overall, especially on text, counters and fine details etc.



I agree, but how long is it going to take for scaling to match a resolution being displayed natively. I don't want to spend twenty years of my life waiting for a TV to be able to 480p decently again.

In my opinion fixed pixel tech is completely the wrong way to go, and in a few years they could have a CRT that is only 3" deep, and multi-sync. A flat display which doesn't remove features for the sake of style.

The current situation is both dipressing and completely avoidable.
Why on earth would you want to shape the future of display technologies around a source that won't even exist in 10 years time? Pretty much the only arguments CRTs have going for them is the black level and response time, which have already been equalled/surpassed by OLED.

CRTs can perform well at a variety of resolutions but don't come anywhere close to fixed-pixel displays running at native resolution. Knobbling the potential for the sake of legacy sources is incredibly short-sighted.
 

KyoDash

Novice Member
It is indeed, but for the next 5 to 10 years in the UK at least, most sources being used will be between 480i and 1080p, with 480i/480p/720p and 1080i being the most used.

Even HD is divided up into three resolutions, SKY insist on 1080i (best suited to CRT, with gaming being largerly 720p, and BluRay 1080p.

Also PC monitors really need to be multi-res native. Case in point, I use 800x600 or 1024x768 for web browsing and most desktop uses, and 1280x1024 for any Imaging or Graphics work I might be doing. I don't need extremely small pin sharp text for Word, Internet and gaming.

My biggest issue with fixed-pixel displays other than scaling, is the fact that most are too sharp for current gaming, producing a more artificial look even when correctly calibrated. LCDs more so than CRT PC monitors, which on some resolutions look too sharp around the edges. More a case of much needed enhancements in real time rendering than an issue with the display (Video or film sources don't suffer from this problem).

I don't see why we as consumers cannot have the choice of superior technology which can do what CRT has been doing for years.

Anyway I'll be waiting for OLED as I find phosphor based displays more pleasing to the eye, Plasma, CRT. Hopefully they will put decent scalers inside these TVs, even if the cost of a 26" will be double the price of an LCD equivilent.

So far I've found LCDs with glass screens to produce a better image than those without, but they don't seem to make TVs like this, just monitors. Another annoyance.

Currently I'm stuck with a 4:3 240p/480i CRT as the picture on LCDs just doesn't cut it for me, compared with a good 480p CRT, which I'm too late to really get hold of (too much waiting on Samsung for their poor excuse for a HD CRT).

I just hope that with OLED they really deliver.

Knobbling the potential for the sake of legacy sources is incredibly short-sighted.
So who is going to support legacy sources then. Seeing as most are still in healthy use today, more so in Asia then here in the UK, but we are still far form adopting regular HD TV broardcast for most channels.
 

onkeh

Novice Member
It is indeed, but for the next 5 to 10 years in the UK at least, most sources being used will be between 480i and 1080p, with 480i/480p/720p and 1080i being the most used.

Even HD is divided up into three resolutions, SKY insist on 1080i (best suited to CRT, with gaming being largerly 720p, and BluRay 1080p.
1080i doesn't require scaling and 720p for gaming is just the limit of the current console generation. I'd be amazed if games don't run at 1080p standard in the next gen.

Also PC monitors really need to be multi-res native. Case in point, I use 800x600 or 1024x768 for web browsing and most desktop uses, and 1280x1024 for any Imaging or Graphics work I might be doing. I don't need extremely small pin sharp text for Word, Internet and gaming.
This can be easily be rectified via software on the PC-end with no need for going out of native res. I purport that the reason no accessible method exists currently is because only a handful of people notice/care.

My biggest issue with fixed-pixel displays other than scaling, is the fact that most are too sharp for current gaming, producing a more artificial look even when correctly calibrated. LCDs more so than CRT PC monitors, which on some resolutions look too sharp around the edges. More a case of much needed enhancements in real time rendering than an issue with the display (Video or film sources don't suffer from this problem).
This is down to personal preference (at a guess I would say you're in the minority) and could easily be resolved by source-end filters. The suggestion to use a visually inferior tech to cover up flaws in the source is very misguided.

I don't see why we as consumers cannot have the choice of superior technology which can do what CRT has been doing for years.
Which superior technology is this?

Anyway I'll be waiting for OLED as I find phosphor based displays more pleasing to the eye, Plasma, CRT. Hopefully they will put decent scalers inside these TVs, even if the cost of a 26" will be double the price of an LCD equivilent.
You already can buy monstrously expensive LCDs that claim to have superior scaling so I don't see why not.

Currently I'm stuck with a 4:3 240p/480i CRT as the picture on LCDs just doesn't cut it for me, compared with a good 480p CRT, which I'm too late to really get hold of (too much waiting on Samsung for their poor excuse for a HD CRT).

So who is going to support legacy sources then. Seeing as most are still in healthy use today, more so in Asia then here in the UK, but we are still far form adopting regular HD TV broardcast for most channels.
Yeah that's great but we're talking about the FUTURE of TV, not the present.
 

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