HDR LEDs

[Kamakazie]

HDR LCD


Thought you all might be interested in this. It certainly looks promising but i dunno wether the likes of SED may be more "user friendly". What with the extremely bright whites etc. causing a blooming effect. I think its something that im gonna have to see for me to really believe its gonna be the next big thing.

Reckon this is related to Phillips ClearLCD or whatever it is? with the LED backlight etc....

[Tef]

Originally Posted by Kamakazie

HDR LCD


Thought you all might be interested in this. It certainly looks promising but i dunno wether the likes of SED may be more "user friendly". What with the extremely bright whites etc. causing a blooming effect. I think its something that im gonna have to see for me to really believe its gonna be the next big thing.

Reckon this is related to Phillips ClearLCD or whatever it is? with the LED backlight etc....

200,000 : 1 contrast

[Kamakazie]

yeah but thats not accurate as because it has a ax lumi of 4000cd/m2 and a min of 0cd/m2 then inr eality its an infinite contrast... the next smallest cd/m2 is something like 0.005 and so they used this to work it out.
That said the new Sharp it mentions claims a 1,000,000 cd/m2 but has a much smaller dynamic range, max of 500 and min of 0.0005... man that will have some awesome blacks!!!

[Reiner]

Very interesting. Thanks for posting that, Kamakazie.

Any place I can buy stocks of that company?

[Kamakazie]

no problem.
suprised its not got more replies but then ive not linked to it in any of the other sections... specifically in the LCD forum.

heh shares might be a good idea but then in these times with SED and Sonys FED etc. theres so many technologies in the pipeline i dont know if this might just miss the bandwagon.

[mavice]

My 2 pence worth

I read the whole article and downloaded the trailers.

Whilst the idea is simplicity itself (I have been mulling over of a way to backlight individual pixels on my PJ for years now to give perfect contrast) I was not entirely sold by the way it was applied.

I understand that 8 bit more signal info limits the number of White LED's that can be addressed but the obvious perfect backlight would have 1 White LED per RGB LED.

This way the brightness of each pixel could be controlled rather than in 'groups'.

The 'Blooming' effect which was touted as a reproduction of the human eye looked blooming awful IMO, (sorry ) from the screen shots and in the LOTR trailer, alot of detail was lost in the image around any bright areas of the screen due to this blooming.

The white rectangle test, the rectangle looked elipticle due to blooming.

Give me 1 White LED per Pixel and let my eyes do their own blooming. OR, even better - make the LCD pixels coloured LED's (oh, thats been done I think...OLED?) so that no backlight is required.

Otherwise, pretty impressive - the futures bright, the futures BLOOMING bright

thanks for the link - interesting reading

[Kamakazie]

Originally Posted by mavice

I understand that 8 bit more signal info limits the number of White LED's that can be addressed but the obvious perfect backlight would have 1 White LED per RGB LED.

This way the brightness of each pixel could be controlled rather than in 'groups'.

The 'Blooming' effect which was touted as a reproduction of the human eye looked blooming awful IMO, (sorry ) from the screen shots and in the LOTR trailer, alot of detail was lost in the image around any bright areas of the screen due to this blooming.

1 LED per pixel is gonna be impossible, you just would never be able to get that many LEDs in a matrix. OLED is he way forward in this respect but as all tech. it has its own drawbacks.

As for the blooming effect, i wasn;t that impressed with the screenshots but then we all know that pictures never do any display panel justice. The camera is in a dark room so all the bright whites are gonna be over exposed and blown out. Id definately want to see this in the flesh before making any assumptions about how it really looks. Im going by what the reviewer said, he said it looked amazing and so im gonna have to take his word for it. Pictures really cant represent the look. THe LOTR thing is again, gonna be overexposed due to the camera.

[Dogboats]

IMHO, after contrast levels, the big problem with LCD picture quality is the "sample and hold" effect. Apparently, it is this effect that is responsible for juddering in fast moving pictures and it's a problem that is still apparent on HD fed LCD displays.

CRTs don't suffer from this problem because the pixels flash rather than hold. The Clear LCD technology from Philips is supposed to fix this by flashing the appropriate backlight for the pixel that have just been refreshed. It will be intersting to see if this introduces flicker - one of the things I don't like about CRTs.

Although it looks like IMLED provides superb contrast, I couldn't see any info on how it might improve "sample and hold" jerkiness.

[mavice]

Originally Posted by Kamakazie

1 LED per pixel is gonna be impossible, you just would never be able to get that many LEDs in a matrix. OLED is he way forward in this respect but as all tech. it has its own drawbacks.

nothing is impossible if enough money can be made from it

In fact, the larger the panel, the easier it gets. The pixel size of a HiDef 60" panel would really not be that small.
LED's are after all just a Silicon Diode and can be make very small if printed on a Silicon wafer / panel.

As suggested in the article, I would guess that the LED size is not the issue - it is the efficiency and subsequent heat dissipation of current white LED's, which is a problem for the current prototype anyway. ...Better to have 1 per pixel and have them RGB too as coloured LED's are way more efficient and hence run cooler.

Very interesting anyway to see how the technology progresses.

[Rimmer]

Originally Posted by Dogboats

IMHO, after contrast levels, the big problem with LCD picture quality is the "sample and hold" effect. Apparently, it is this effect that is responsible for juddering in fast moving pictures and it's a problem that is still apparent on HD fed LCD displays.

CRTs don't suffer from this problem because the pixels flash rather than hold. The Clear LCD technology from Philips is supposed to fix this by flashing the appropriate backlight for the pixel that have just been refreshed. It will be intersting to see if this introduces flicker - one of the things I don't like about CRTs.

Although it looks like IMLED provides superb contrast, I couldn't see any info on how it might improve "sample and hold" jerkiness.

Brightside's HDR technology is said to modulate each LED faster than video refresh rates. Difficult to say what effect if any this will have on traditional LCD sample-and-hold issues. Perhaps there will be no difference?

According to an HCC article ClearLCD converts 50Hz to 75Hz. While 75Hz scanning should suit 25Hz speed feature films, I can't help thinking that it will introduce unwanted juddering on 50Hz video sources. 100Hz progressive scanning would avoid this problem.

[Dave163]

Not being a TV engineer myself perhaps someone wiser than me can explain why a much simpler solution hasn't been tried. Assuming I'm right that LCD screens work by essentially having lots of tiny red, green and blue pixels with a single white backlight covering the whole of the screen behind the pixels, why not have a second layer of pixels sandwiched between the "front" pixels and the backlight to increase the contrast ratio? If the front layer of pixels manage say 500 gradations from fully transparent to fully opaque (at least, as transparent and as opaque as LCDs can get), and there was a layer of pixels immediately behind this layer that offered, for each level of brightness, a further 500 levels between white and black, you'd have 500x500 potential levels of blackness ie contrast ratio of 250,000.

OK, lining up a matrix of 1080 by 720 pixels with a second layer of pixels 1080 by 720 would be tricky. But if it's possible to compromise by having a matrix of only around 40 by 40 white LEDs with variable levels of brightness in place of the backlight to create the HDR LED sets, at a cost of $40,000, would it not be cheaper to have a layer of LCD material sandwiched between the coloured pixels and the backlight that was only say only 40 by 40 giant "pixels" - each of which was behind dozens or hundreds of the front layer of pixels, and each of which could modulate its transparency to let in different amounts of the backlight in the same way each LED lets in diferent amounts of light? Problem solved for a fraction of the cost.

Perhaps I should rush a patent through before someone else tries it...

Dave163

[Kamakazie]

Originally Posted by mavice

In fact, the larger the panel, the easier it gets. The pixel size of a HiDef 60" panel would really not be that small.
LED's are after all just a Silicon Diode and can be make very small if printed on a Silicon wafer / panel.

As suggested in the article, I would guess that the LED size is not the issue - it is the efficiency and subsequent heat dissipation of current white LED's, which is a problem for the current prototype anyway. ...Better to have 1 per pixel and have them RGB too as coloured LED's are way more efficient and hence run cooler.

i agree to an extent but then are LEDs that small gonna put out enough light to backlight an LCD reasonably?

[Daddy k]

lets not forget a lot of problems that are coming up now is not how to get the pixels/led's lighting up quick etc, its getting em to turn off quick enough!