HDTV Almanac - CES 2010: LED Backlights Take Over

[alfredpoor]

LEDs are a solid state light source that have extraordinarily long lifetimes, and do not use mercury or other environmentally hazardous chemicals that are found in the fluorescent lamps traditionally used as backlights for LCD panels in devices such as computer monitors, notebook displays, and HDTVs. In addition, LED backlights provide better color performance, resulting [...]

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[lmarks]

You wrote

"LEDs are a solid state light source that have extraordinarily long lifetimes, and do not use mercury or other environmentally hazardous chemicals that are found in the fluorescent lamps traditionally used as backlights for LCD panels in devices such as computer monitors, notebook displays, and HDTVs. "

Actually, LEDs are made of various compounds including gallium arsenide, gallium aluminum arsenide, gallium aluminum arsenide nitride, etc. The arsenide is Arsenic in compound. Some people might classify this as hazardous, although the arsenic in these doesn't readily transfer to the environment as mercury does.

[alfredpoor]

lmarks: you're certainly correct. The difference is that the amount of arsenic in an LED -- or all the LEDs ina single TV -- is tiny compared with the amount of mercury used by an equivalent fluorescent backlight. And, as you point out, it is much less likely to find its way back into the environment in any significant way.

Alfred

[Roger Halstead]

Now if they'd just come up with a retrofit that would allow the use of LEDs to replace original backlights for LCDs. Or have they?

[alfredpoor]

Very few LCD panels make provisions for replacement of backlights, let alone retrofits. After the five years or so that it would take for a computer monitor backlight to dim appreciably, it would no doubt be cheaper and easier to replace the entire display than try to find a compatible fluorescent backlight. Replacing the backlight with LEDs would require new light guides, diffusers, light recovery layers, as well as major changes to the controller circuitry (which probably exists on a monolithic board that does not change components easily). And when you're done, it's possible that the color filters used on the LCD panel will not be optimized for the new LED light source.

Yes, you can drop a classic Ford 289 V8 into a VW Beetle chassis, but it's not easy and probably not worth the expense. A similar case would apply to LCD displays.

Alfred