Research With a Bright Future: GE Develops Flexible, Thin, Lightweight Sheets That Could Someday Replace Light Bulbs

Jun. 23--NISKAYUNA -- The piece of plastic is clear, until Anil Duggal begins fiddling with some knobs as he applies electric current.

Soon, the plastic is glowing blue and then red -- a bright little sheet of light -- as he moves the knobs on an attached power pack.

Duggal, advanced technology leader in organic electronics at the GE Global Research Center, hopes these glowing sheets of light will some day replace less efficient incandescent and more expensive fluorescent bulbs. He has been working on developing these organic light-emitting diodes, or OLEDs, since at least 1999.

In that time, he and other researchers have been able to make the OLEDs more efficient. They've also managed to place them on flexible plastic that bends and to scale them up to larger sizes.

Traditional light-emitting diodes are basically semiconductors, carefully fabricated in batch processes. And the light they produce is distinct. Even in a traffic light, the individual dots of red that make up the light are apparent.

"LEDs are more naturally a point source" of light, Duggal said. "OLEDs are more naturally a diffuse source" -- like a fluorescent bulb.

"You'd never make a flashlight out of a fluorescent bulb," he said. But you would light a room with it, just as you would light a room with OLEDs.

The organic material includes carbon, hydrogen and oxygen, arrayed in a proprietary structure that is especially effective at emitting bright light.

Because of their two-dimensional appearance, OLEDs could be used almost as wallpaper, or maybe even as curtains, that light up a room. Because they're flexible, they could take on different shapes.

Duggal's research team is working on ways to inexpensively produce the OLEDs.

They envision printing the organic material on a roll of foil or plastic substrate in a continuous process. Duggal compares it to producing a newspaper.

This approach could cut costs. One hurdle, sealing the organic materials from water and oxygen, has been accomplished with the development of a barrier, or encapsulation, technology that GE has already licensed to TOKKI Corp. of Tokyo.

Other challenges -- making the OLEDs last longer and improving the light output per watt -- are also being tackled.

"From 2003 to now, we went from 15 lumens (a unit of light measurement) to 64 lumens per watt with white OLEDs," Duggal said. But that's still below the 100 lumens per watt produced by fluorescent lights.

The researchers also are working on ways to make the OLEDs last longer.

In March, GE announced an alliance with Konica Minolta Technology Center Inc. and Konica Minolta Holdings Inc. to accelerate the commercialization of the technology.

"Having such unprecedented attractive features as flexible, thin, lightweight and sheet form, OLED lighting is considered one of the most promising new business opportunities for us in the future," said Masatoshi Matsuzaki, president of the Konica Minolta Technology Center.

The goal is to bring the OLEDs to market by 2010.

"We're hoping ... to have some more niche products, to get our feet wet, and understand what our market will be," Duggal said.

Eric Anderson can be reached at 454-5323 or by e-mail at eanderson@timesunion.com.

Organic light-emitting diodes -- or OLEDs -- promise to be less expensive to produce than traditional LEDs and have surpassed incandescent light bulbs in efficiency. Here's how OLEDs compare as a source of light. Light source \\\ Lumens per watt Incandescent bulb \\\ 15 OLED, in 2003 \\\ 15 OLED, current \\\ 64 Fluorescent bulb \\\ 100 Source: GE Global Research Center

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