Fantasy shootout....SED vs OLED?

[stuartbrown21]

I know this will probably never happen as SED is unlikely ever to get to market, but in theory, which one of these technologies would give the most 'perfect' performance?

As I understand it they both have huge advantages in terms of black levels / contrast / response time, compared to current flat screen technologies.......

[Phantoma]

Well I remember reading that SED was a type of rear projection so it probably would have had a viewing angle limitation whereas OLED doesn't.

[NicolasB]

Originally Posted by Phantoma

Well I remember reading that SED was a type of rear projection so it probably would have had a viewing angle limitation whereas OLED doesn't.

No.

The best way to imagine SED is that it's like CRT, but instead of a single, scanning electron beam sweeping across the whole screen, each individual sub-pixel has its own dedicated electron gun. So you end up with a display that has all of the benefits of CRT (because you're generating the image the same way - electron beam stimulating phosphors) but avoids most of CRT's disadvantages (e.g. the need for a long tube, imperfect geometry, convergence issues, overscan that varies with picture brightness, etc.).

I would speculate that SED would initially be better suited for large-screen displays - what is currently the plasma market - while OLED would begin with smaller devices - the current LCD market.

[Otto J]

Originally Posted by stuartbrown21

I know this will probably never happen as SED is unlikely ever to get to market, but in theory, which one of these technologies would give the most 'perfect' performance?

As I understand it they both have huge advantages in terms of black levels / contrast / response time, compared to current flat screen technologies.......

I would believe SED would have superior performance potential. I have no evidence of this theory, but the fact that OLED has an issue with the lifetime of the panels, especially that they're different for each color, tells me that there will probably be issues with color performance over time, and also probably with uniformity (although I must state again that I'm just guessing here). SED should perform similar to plasma in this regard.

Also, the areas where OLED is supposed to outperform current technologies, are - apart from contrast ratio - areas that we don't really need to improve in: Light output, and color gamut. The light output of most PDP's and LCD's are basically sufficient for use in normal living room conditions, and the color gamut of most tv's already exceeds the color gamut of the source material available, to the point where one of the most important performance attributes has been how far away the TV's have become from the source gamut, and the set's ability to emulate the gamut of the source.

Basically, we shouldn't get too carried away with the promises of these new technologies, simply because of the fact that the performance limitation in today's sets for the most part doesn't have much to do with the limitations of the technologies at hand. SED and OLED will deliver very little in terms of performance, that the Pioneer PDP panels don't already have. Small increases in the "cleanness" of the image (getting rid of, or decreasing, dithering for instance) will be noticeable, but small steps in the right direction. But most of the issues with TV's today has to do with the manufacturers deliberately not trying to deliver accurate pictures. 95% of the TV's available on the market today, would not match the performance of a Pioneer, if you changed the panel to SED or OLED, and left all other performance attributes untouched. Just because sets will become available with newer technologies, doesn't mean that they will actually deliver the performance that is theoretically reachable with that tech, just as no LCD TV currently deliver the performance that should be available from LCD from this point, and even Pioneer don't deliver the performance that could be reached with PDP - simply because of limitations in the signal processing. You can correct much of this with an outboard video processor, but it will never be as good as if the tv's were perfectly constructed from scratch.

I personally believe, that if you took basically any decent panel currently available, and built a TV around it using the design concept that Joe Kane has developed for the Samsung projectors, you would end up with easily the best TV on the market. Currently, no manufacturer comes close to delivering truly accurate pictures, and I sadly don't see why that should change, just because we introduce SED or OLED to the mix. On the contrary, these techs will introduce new ways for the manufacturers to deliberately diverge from the standards.

[NicolasB]

Originally Posted by Otto J

I would believe SED would have superior performance potential. I have no evidence of this theory, but the fact that OLED has an issue with the lifetime of the panels, especially that they're different for each color, tells me that there will probably be issues with color performance over time, and also probably with uniformity (although I must state again that I'm just guessing here). SED should perform similar to plasma in this regard.

CRT and plasma have problems with "uniformity" - otherwise known as screen-burn. They also suffer from unequal ageing of different colour elements: blue phosphors age faster than red and green phosphors. Recent OLED displays have done away with blue OLEDs entirely, and now use white OLEDs with a blue filter instead; this should more or less eliminate ageing issues. If anything I think OLED would probably be less prone to ageing effects than SED would be.

Originally Posted by Otto J

Also, the areas where OLED is supposed to outperform current technologies, are - apart from contrast ratio - areas that we don't really need to improve in: Light output, and color gamut. The light output of most PDP's and LCD's are basically sufficient for use in normal living room conditions, and the color gamut of most tv's already exceeds the color gamut of the source material available, to the point where one of the most important performance attributes has been how far away the TV's have become from the source gamut, and the set's ability to emulate the gamut of the source.

I'm not sure that's entirely true. One of the major drivers behind using LEDs or lasers as the light source in projection systems is that the light sources used tend to have poor spectral distribution. UHP bulbs used in projectors, for example, tend to be deficient in red to the extent that if the white point is properly callibrated it severely damages the contrast ratio, and sometimes even the gamma curve (because you have turn up the red gain and turn blue and green gain down).

Off the top of my head I'm not sure how good the spectral distribution is for LCD light sources, but I wouldn't be surprised if it had similar issues. Certainly the descriptions of LCDs with LED backlights suggest major performance gains compared with current-generation devices.

As well as contrast ratio, there's also the question of response times and motion artefacts. LCD has problems with motion because each frame is displayed for the full duration of that frame before switching rapidly to the next; this makes for much less authentic motion than (say) CRT where the frame is only flashed up for a split second and then turns dark. LCDs that use LED backlights can achieve this, but conventional LCDs can't.

Plasma has motion artefacts and "rainbow" effects of its own because of the way it operates: instead of varying the brightness of a subpixel it is always either full on or full off, and perceived brightness is controlled by lighting it for a greater or lesser percentage of each frame. That creates various visual problems. 3-chip DLP systems suffer from similar issues (and 1-chip DLP is an unholy, rainbowed mess). With OLED and SED we can go back to a tech where each individual pixel can have its brightness directly controlled (unlike plasma or DLP) and where the image can be scanned (unlike present-day LCD).

Originally Posted by Otto J

Basically, we shouldn't get too carried away with the promises of these new technologies, simply because of the fact that the performance limitation in today's sets for the most part doesn't have much to do with the limitations of the technologies at hand.

I disagree. (See above).

Originally Posted by Otto J

SED and OLED will deliver very little in terms of performance, that the Pioneer PDP panels don't already have.

(cough)

I'm sure Pioneer would like you to believe that, but don't confuse their "concept" devices with actual shipping products; remember that Pioneer isn't going to be making plasma panels any more (merely rebadging panels made by someone else) so we won't be seeing any of Pioneer's interesting technical breakthroughs in any real plasma device.

Even just in terms of black level there's a huge difference between what SED and OLED have to offer and what any actual device now on the market can produce - and that likely applies to many future devices too.

[Otto J]

Originally Posted by NicolasB

CRT and plasma have problems with "uniformity" - otherwise known as screen-burn. They also suffer from unequal ageing of different colour elements: blue phosphors age faster than red and green phosphors. Recent OLED displays have done away with blue OLEDs entirely, and now use white OLEDs with a blue filter instead; this should more or less eliminate ageing issues. If anything I think OLED would probably be less prone to ageing effects than SED would be.

You may be right, as I said, I'm merely guessing.

Originally Posted by NicolasB

I'm not sure that's entirely true. One of the major drivers behind using LEDs or lasers as the light source in projection systems is that the light sources used tend to have poor spectral distribution. UHP bulbs used in projectors, for example, tend to be deficient in red to the extent that if the white point is properly callibrated it severely damages the contrast ratio, and sometimes even the gamma curve (because you have turn up the red gain and turn blue and green gain down)..

For light sources in projectors, definately there are improvements to be made by newer technology. This is arguably THE area that needs the most improvement right now (apart from LCD's having loads of room for improvement...) But this thread isn't about projectors...

Originally Posted by NicolasB

Off the top of my head I'm not sure how good the spectral distribution is for LCD light sources, but I wouldn't be surprised if it had similar issues. Certainly the descriptions of LCDs with LED backlights suggest major performance gains compared with current-generation devices.

As well as contrast ratio, there's also the question of response times and motion artefacts. LCD has problems with motion because each frame is displayed for the full duration of that frame before switching rapidly to the next; this makes for much less authentic motion than (say) CRT where the frame is only flashed up for a split second and then turns dark. LCDs that use LED backlights can achieve this, but conventional LCDs can't..

Well... I wasn't comparing the new technologies to LCD, since I believe LCD's are far from the benchmark of todays flatscreens. I do belive that any technology available today can be bettered, certainly plasma as well, however, considering the performance of Pioneer's plasma panels, I believe the improvements gained from removing the issues with these panels will have less impact on actual picture quality, than it would to simply make the manufacturers get things right. Of course, one doesn't rule out the other, but if we consider the Pioneer PDP-LX5080, let's imagine we have two possibilities: A: keep the panel, but upgrade the scaling engine to Radiance/VP50Pro class and deliver truly linear color performance. B: Keep the scaling and color properties, but insert "new panel type" that removes all plasma-related picture issues. Which would be the better performer? I vote A. If we take it one step further, and evaluate the performance pre-calibration, and imagine scenario A includes decent oob factory settings, and scenario B with the same settings as today (including DNR, Dynamic contrast etc), scenario A will _definately_ be better.

[stevieboy]

very interesting,the current "KURO" range of pdp is without doubt the finest available at present and by finest i mean in all aspect of panel assessment. its interesting ten that pioneer will no longer produce their own panels ,buying in from ?????? and releying on propietry tech to "fix" the picture.Hmmmmm!
informed comment would sugest that pio can no longer afford the dosh to keep producing prime panels as the pdp market is begining to wilt in the face of increasing competition from cheaper and increasingly equivelant lcd panels.OLED etal will underscore the rising star that is lcd whereas pdp will never speciate,ie spawn a natural succesor.
SED may well have been an ideal evolution of the pdp/crt family line but has suffered from political bukk crap and stunted growth.