Pioneer Demos New Plasma TVs

Pioneer, which is sticking to making plasma flat-panel TVs as other manufacturers are switching to LCD TVs, have announced they will be demonstrating a prototype set that emits no light in black areas of the picture, improving contrast and image quality.

Neither plasma nor LCD sets on the market today can display a perfect black unless they're off. The cells of a plasma display need a constant "priming current" to stay active, which makes them glow faintly.

Liquid-crystal displays, or LCDs, contain a backlight, which the liquid-crystal layer cannot block completely, meaning light shines through even in the darkest areas of the picture.

The difference between a set's minimum and maximum brightness is expressed as a contrast ratio: a good set may be 30,000 times brighter in its highlights compared to the blacks. With no light emitted from the black areas of the picture, the Pioneer prototype effectively has an infinite contrast ratio.

Pioneer said it would show the prototype at International Consumer Electronics Show in Las Vegas, which starts Monday.

In the LCD camp, manufacturers are improving contrast ratios by replacing the fluorescent backlight with light-emitting diodes, or LEDs. They can be turned off in zones, improving overall contrast ratios, but don't enable pixel-by-pixel control of emitted light.

Another display technology, organic LEDs, or OLEDs, does allow for a perfect black. But for now, those displays are too expensive for the mainstream market. Sony Corp. sells an 11-inch set for about $1,700.

OLED sets also can be very thin, down to an eighth of an inch. Pioneer is countering by showing a plasma prototype that is just 9 millimeters thick, or 3/8 of an inch, claiming it is the thinnest 50-inch set ever.

"There's so much noise getting around about all these technologies, we thought it was important to show what (plasma) displays can do today," said Russ Johnston, an executive at Pioneer Electronics (USA) Inc.

Johnston said neither the thin display nor the perfect black technology will be ready for the market in 2008. "It's close, but not that close," he said in an interview.