Improve the Look of Your LCD

If you ask anyone who cares about the look of their HDTV or graphics workstation display, they'll tell you the same thing: LCDs don't reproduce color very well. But over the next few years, that situation may change, thanks to improved backlighting using LED technology.

Sony's Qualia 005
Don't make your purchasing plans just yet, however. Sony plans to ship the first line of LED-backlit TVs, dubbed Qualia 005, in November, but--as is the case with many other emerging technologies--only in Japan. Currently the company has no plans for a U.S. release.

And these televisions won't be cheap. The 46-inch model will cost 1,102,500 yen (about $10,000); the 40-incher will cost 840,000 yen (about $7600).

Sony designed its LED technology, called Triluminos, with the help of Lumiled Lighting. The latter company, which calls its LED backlighting technology Luxeon, will supply Sony with the LEDs. Lumiled has a similar relationship with NEC, which is also working on LED-backlit LCD monitors.

Behind the Screens

"Most people don't realize that LCDs are limited in the color spectrum because of the lights behind them," says IDC analyst Bob O'Donnell. If you improve the backlight, you improve the color, he says.

Conventional flat-panel LCDs use cold cathode fluorescent lamps for backlighting. The colors of light that a CCFL emits span the range of the visible spectrum, and a person looking at the backlight sees this mixture of frequencies as white light.

Each pixel has three tiny filters, one red, one green, and one blue; adjusting the amount of light through those filters yields mixtures of various quantities of red, green, and blue light. Because of the way the human eye works, different mixtures of those primary colors are all it takes for a person to perceive all the different colors across the visible spectrum.

Luxeon emitter
Instead of a CCFL, Luxeon and Triluminos technologies use an array of red, green, and blue LEDs; again, humans perceive the mix of these lights as white. But when, for instance, the green and blue are filtered out of a pixel, you get the pure, saturated red of a red LED (unlike with the "white" light source of the CCFL, which permits a range of red frequencies through the filter). And these purer primary colors yield better-looking mixtures, as well.

According to Lumiled, the results are dramatic. Sony's new TVs are supposed to deliver a color gamut equivalent to 105 percent of the NTSC color space. By comparison, most LCDs manage only 65 to 75 percent, and even CRT monitors generally provide around 80 percent.

IDC's O'Donnell is enthusiastic about the new approach. "I think it's a great technology.... Color purists still don't want to go with LCD monitors because of [the displays' color] limitations. Well, guess what? Now they can."

Taking Control

In addition to better colors, LED backlighting gives you more control, allowing you to fine-tune the colors on your set. And according to Mark Pugh, Lumiled vice president, Sony's new TVs will even be self-correcting.

"We have a sensor that detects red, green, and blue" and will maintain your color settings, "even though LEDs vary over time," he says.

The technology has other advantages, too. According to both Pugh and IDC's O'Donnell, LEDs pose less potential hazard to the environment than CCFLs because they don't contain mercury. They also have a longer lifetime and are less prone to breaking. On the other hand, they use more power, which is why you probably won't see them in notebooks any time soon.

In fact, unless you're reasonably affluent, you probably won't see them in your living room soon, either. O'Donnell predicts, "In the near future, [they won't be] common because they'll be too expensive. But in two or three years, they'll be common." They are, he adds, "clearly the way to go."

This story, "Improve the Look of Your LCD" was originally published by PCWorld.

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