Who said LCD technology couldn't compete with PDP?

[PC-Engine]

http://gizmag.com/go/3414/

40,000:1 CR

 

[Nick]

Using a LED per pixel was the obvious thing to do. But I'm not sure how well they can control color accuracy with this. It would require current control per pixel (is that the box below it)? Either way it sounds very promising and I'm looking forward to any technology to improve flat screens!

Edit: Oops, I should have read the details: "Each individually controlled LED backlights a small region of the LCD panel. This has the effect of multiplying the modulation of the two displays which provides the substantial gain in dynamic range. Thanks to software correction algorithms and the natural effects of scattered light in the human eye the blur introduced by the low resolution LED image is imperceptible, and the result is a high resolution, high dynamic range final image."

 

[PC-Engine]

These displays were shown at ACM Siggraph 2004 and could be seen at Nvidia's booth.

 

[Leto]

Sry but how do they measure it to 40.000 / 1 CR, when the max luminance is 200.000 cd/m2 and the minimum is nill (because the led is off). 200k cd/m2 how much is that compared to a cars headlights? (it sounds kinda dangerous)

 

[Guden Oden]

Powerful LEDs, such as ones used in many optical mice etc have outputs around 8k Cd, and they are definitely uncomfortable, bordering on painful to the eye when looking straight into them... 200k, well, uhhmm... I guess that thing could light up a whole room quite comfortably.

 

[PC-Engine]

Power consumption in the HDR display is first order linearly related to the average image brightness. We are using 759 LED at 1 Watt each so the highest total power consumption of the display would be approximately 759W (plus some for the drive electronics, etc). The system is not designed to do this and in fact has build in methods to prevent this from happening.
Almost all images have most of their content in the luminance range of normal displays (which corresponds to the bottom 5-10% or so of the HDR display) and only a few highlights and bright areas. We have taken random samples of images from the web (mixed indoor and outdoor) established the average power consumption to be in the range of 150-80W. Outdoor scenes are generally in the higher end of this range and indoor at the lower end. Of course, a lot of images are lower than this range such as dim indoor images and all conventional 8-bit images (unless extended in some way). Few images exceed this range, as they would be unpleasant to the eye.This is comparable to CRTs of the same size and slightly higher than LCD power consumption. Obviously, reducing the peak luminance, currently 20x higher than any other conventional display, can shift this this relationship.

 

[Leto]

Hackers could make your browser show high luminance images and blind you Norton Sunglasses

 

[PC-Engine]

 

[Killer-Kris]

Following the logic of YUV and the other luminance color schemes wouldn't it have made more sense to have the backlighting be high resolution and the LCD a lower resolution.

Of course after reading the bit about the power consumption I definitely see how that wouldn't be possible, but if you could do that with lower power LEDs wouldn't that actually go a long way towards a better image as well?

 

[Basic]

Have you seen a price tag on it?
The only thing I've seen was an article that had this subtitle for the part about Sunnybrook's monitor:
"$90,000 for a Monitor?"

If that was true, ouch.

Btw, does anyone know how efficient a high power LED is? I guess it beats a normal incandescent light quite easily, but does it beat fluorescent lights also?
I know that all 759 LEDs aren't supposed to be on max power at the same time, but I think it's still interesing. If it's anything like 759W of fluorescent lights, then thats an insane amount of light.

But I don't understand that they've built this kind of monitor, which use a normal LCD unit, but didn't get a better LCD. Why not use the same LED-resolution, but spread them a bit more and use a 20" 1600x1200 screen. It seems like a strange place to save money. Or have they hit the limit on the LCD resolution vs LED resolution?


Killer-Kris:
I assume you think:
LED - luminance
LCD - chrominance.

But that's not how it's done. It's:
LED - peak(?) luminance over area,
LCD - detailed luminance, and chrominance.

It's done that way since it's much easier to get high res from the LCD than with LED's. If they were able to make LED displays with high enough res for the luminance, they could just as well skip the LCD all together. They could just use colored LEDs instead.

So until we see any high intensity OLED displays, this is a good way.

 

[Guden Oden]

but does it beat fluorescent lights also?

From what I've read, no. Not yet at least, will hopefully happen with quantum spot LED tech or other esotheric techniques.

If they were able to make LED displays with high enough res for the luminance, they could just as well skip the LCD all together.

I don't know if the resolution is the real issue, it's probably rather a question of straight LED displays aren't practical. Three LEDs per pixel at above-megapixel res means a silly number of LEDs, and they need to be near-microscopic in size or else the monitor will become the size of a wall.

 

[Killer-Kris]

Killer-Kris:
I assume you think:
LED - luminance
LCD - chrominance.

Yup, that's pretty much how a envisioned it...

But that's not how it's done. It's:
LED - peak(?) luminance over area,
LCD - detailed luminance, and chrominance.

And a few minutes after posting I thought about it a few more minutes and realized that something like that might be a problem. But definitely a big thank you for putting into better words than I ever could have hoped for.

It's done that way since it's much easier to get high res from the LCD than with LED's. If they were able to make LED displays with high enough res for the luminance, they could just as well skip the LCD all together. They could just use colored LEDs instead.

I had always thought/heard that colored LEDs have a hard time doing accurate color representation. Or is that something of the past?

 

[Basic]

Oden:
The silly number of LEDs, and the size they need to be to get a reasonabely sized monitor, is the reason why high res is impractical. I don't think we disagree on atnything there.

I had always thought/heard that colored LEDs have a hard time doing accurate color representation. Or is that something of the past?

I must admit that I haven't looked much into that. I've always thought that LEDs usualy produce a reasonabely narrow banded light, which would be good for color generation. But it's probably a different color gamut than used in CRT/TFT monitors, so you'd need to convert from usual RGB to LED-RGB. I might be wrong about that though.

Or it could be that a LED-RGB triple could generate all colors you want. But you'd still need to calibrate each pixel separately, since the current needed for a certain intensity could vary a lot from LED to LED. (LEDs are binned for both color and intensity.)


I found another news clip about the price.

AV Pro Magazine[/url]]Seetzen estimates that when the technology is commercially available in late 2004, an HDR display will cost 15 percent to 20 percent more than a conventional LCD display.

That's certainly more promissing than what I read earlier. But it does seem rather optimistic.

[Edit]
And one more clip:

Seetzen[/url]]For a 20 inch medical LCD the added costs will probably be around $500 or so

Which seems more reasonable. Maybe he was talking about a conventional medical LCD above. (Which are far from what I would call a conventional LCD, considering the extreme resolution they often have.)

 

[Simon F]

Hackers could make your browser show high luminance images and blind you Norton Sunglasses

+1 Funny

 

[micb]

Powerful LEDs, such as ones used in many optical mice etc have outputs around 8k Cd, and they are definitely uncomfortable, bordering on painful to the eye when looking straight into them... 200k, well, uhhmm... I guess that thing could light up a whole room quite comfortably.

LED's like the the ones on a optical mouse have a narrow degree beam, some of the blue torches I have made use 15 degree beams.

A monitor like LCD has a far wider degree angle of light.

 

[Mintmaster]

I always thought it would be kind of neat if someone applied this to rear-projection technology. Imagine a low-res DLP chip (taking the place of the LED array), and a transmissive LCD screen in front. Then you could get extremely high contrast ratio (better than DLP alone), you don't need a colour wheel (and thus no rainbows) but still only need 1 DLP chip, and you could get the benefits of LCD for HT purposes (better for SD, supposedly better colour).

Anyone else here following RP technology?

 

[Sxotty]

If you could fix LED's that broke and it wasn't a ridiculous price it could be nifty.