SID 2011: LCD Weight Loss

I want to tell you about what I saw yesterday that could have major implications for LCD HDTVs. A new technology from 3M can save weight and drive out all sorts of cost from large LCD panels.

A typical panel for an LED edgelit LCD has a reflective layer in back along with a bunch of free-standing optical films: a light guide, diffusers, collimators, and so on. 3M has come up with a way to use a single, multi-layer optical film that is applied directly to the back of the LCD panel, the rear reflector, and nothing else. The air gap between the two layers does a far more efficient job of mixing the light from the LEDs, creating a uniform backlight.

The most obvious advantage is that it eliminates 90% of the light management materials, which can amount for as much as 6.6 pounds in a 55-inch set. That saves material and assembly costs, as well reducing shipping costs due to the lower weight. So far, so good.

But designers can also use fewer LEDs for the edge light. The standard spacing is 12 mm between LEDs; anything less, and you get a “headlight” effect where you can see bright spots for each LED along the edge of the panel. The 3M solution mixes the light better; the company has demonstrated a uniform backlight with LEDs spaced 60 mm apart. Wider spacing means lower assembly costs and possible improvements in heat management.

The better mixing also means that less expensive LEDs can be used. Instead of the expensive binned units with precisely the desired color temperature, a mix of “warmer” and “cooler” LEDs can produce the same color backlight for less money.

This new technology has additional advantages that will help designers wring even more cost out of LCD displays, which will make consumers happy as it will help continue the downward price trend that we have come to expect.