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TwitterThis is part of IEEE Spectrum's special R&D report: They Might Be Giants: Seeds of a Tech Turnaround.
Kevin Dowling points the light at me and suddenly, in a head-splitting blaze of white, I'm ready to confess. It's true, I'm ready to blubber; I had been thinking that light-emitting diodes (LEDs) were basically just dim and dowdy indicator lights. I had no idea that they had become bright enough to make an iguana squint.
The light Dowling is wielding consists of 56 white and 7 amber-colored LEDs. The total package occupies an area not much bigger than a letter-sized sheet of paper and it throws about 1900 lumens—more than both headlights on the average automobile. And this little demonstrator is not even state of the art. Outfitted with the brightest of the white LEDs on the market, it would throw an astounding 7500 lm—almost as much as a typical sodium-vapor street light.
Dowling, who is vice president for strategy and technology at the start-up company Color Kinetics Inc. (Boston), is one of the hundreds of researchers harboring some very big dreams for some specks of gallium nitride roughly a millimeter square. With impressive longevity and potentially mind-boggling efficiency, these chips pour out photons in almost any color and with dazzling intensity. The idea that these tiny semiconductors might replace the venerable incandescent light bulb—a technology so successful that it has become the very symbol of innovative insight—has gone from preposterous to plausible indeed.
The key development in that transformation was the invention of the gallium nitride (GaN) LED, which made it possible to get white light from a semiconductor. It has been more than six years since a then-little-known researcher named Shuji Nakamura, at Nichia Corp. (Anan, Japan), stunned semiconductor researchers by coaxing beautiful blues, greens, and purples out of GaN—and doing so reliably. Nakamura has since decamped to the University of California, Santa Barbara, but the revolution he launched is just starting to get interesting.
GaN LEDs are already quietly transforming specialized illumination, including architectural and stage lighting, indoor and outdoor accent lighting, traffic and railway signaling, commercial and retail signs and displays, and outdoor illumination on bridges, walkways, gardens, and fountains. Every night, the almost surreally saturated hues of LEDs bathe a suspension bridge in Philadelphia, a nightclub in Miami, a movie palace in New York, hotels in Japan, the United States, and Europe, casinos everywhere, and too many other buildings to count. All told, the market for LEDs that throw at least several lumens of light was US $1.2 billion last year, according to Robert Steele, an analyst at the market research firm Strategies Unlimited (Mountain View, Calif.).
But the brightest is yet to come, researchers say. They have set their sights on the $12 billion-a-year market for sources of white light, including light bulbs and fluorescent tubes. In fact, you can already light your home with them, if you managed to escape the collapse of the tech bubble with vats and vats of cash.
You can now buy, from Lumileds Lighting LLC (San Jose, Calif.), a GaN-based white-light LED that throws about 120 lm. Six of them will use just 30 W but give you almost as much light as a 60-W incandescent bulb. Unfortunately, those six LEDs could cost you about US $120. A Lucerne, Switzerland-based bank lights its boardroom with white LEDs. And Osram-Sylvania (Danvers, Mass.) used 11 300 white LEDs and 5700 amber ones to light up part of the Jefferson Memorial (Washington, D.C.). White LEDs are also lighting the dashboards of a few luxury cars, and prototype vehicles with LED headlights have been unveiled [see photo]. Coming generations of cell phones are expected to use white LEDs for backlights.
Of course, semiconductor specialists have plenty of work to do before they can turn this expensive novelty into a mass-market source of illumination. Lumen for lumen, white LEDs cost roughly 100 times as much as an incandescent bulb. Not to worry, say researchers. Not only will they get the cost down, they are going to dazzle us with devices that will be 10 times as efficient as an incandescent and will last 100 times as long. By mixing light from LEDs of different colors, the devices will provide 1000 shades of white—or any hue under the sun—at the twist of a dial.
"The ability to change both intensity and color—that is going to bring on a new way of thinking about illumination," says Ihor Lys, an IEEE member and cofounder of Color Kinetics, which uses LEDs in sophisticated color lighting systems. What transforms the idea of a future lit by chips into more than just a vivid pipe dream is the fact that every one of the world's top lighting manufacturers, including General Electric [ranked (43) among the Top 100 R&D Spenders], Osram-Sylvania, and Philips (24), has sizable LED-lighting research efforts and joint ventures under way.
