LAMP vs. LED

[Shinma]

Originally Posted by welwynnick

Can't wait to see the back of lamps, though I don't think the potential of LEDs has been exploitd yet. The tests I saw said the contrast was lower because of the lack of a dynamic iris, but I don't think that's anything to do with LEDs in themselves. LED sets seem to have potentially the best colour performance of all, though the forthcoming Mitsubishi laser TVs should be good as well.

Nick

As long as the LEDs aren't so dim, and the light so structured, that when they diffuse the array of LEDs to remove the structure the light is transmitted at higher angles than that of a florescent system, I don't see a fundamental reason why the LED TVs should have a worse contrast ratio at the same refresh rate. I would think the LCD portion itself should be the same..... Although, if they are trying to drive them 3 times as fast to cycle the colors, that would have an impact on at least color accuracy, if not contrast.

LEDs have two possible advantages for color performance. The exact color anchoring points are more arbitrary because they aren't constrained by peaks from phosphor, and the band should be more narrow. This last one isn't fundamental, because you could filter the tube output to an even more narrow wavelength range, but you don't want to give up that much light. The laser TVs, on the other hand, have as narrow a band as you can get, but technology limitations may not anchor those colors at the ideal points to cover the largest gamut. With today's technology, high efficiency laser output is pretty constrained to specific wavelengths once you approach wavelengths shorter than mid-red. While they aren't ideal, I think they are far better than the constraints of phosphor, so I anticipate these TVs will look really nice. I'm not sure it's a really fair comparison though, since I think the laser TVs that are coming out are rear projection and not being used as illumination for an LCD screen. Because of price/power and coherence issues, I'm not sure I see them being used as back lighting for an LCD panel.