Here's a really cool advance in lighting.LED Evolution Could Replace Light Bulbs
Evolution of Versatile LEDs Could One Day Make Thomas Edison's Light Bulb a Thing of the Past
Patrick Durand of Lumileds glows green under LED backlighting at the Lightfair International lighting convention in New York Tuesday, April 12, 2005. (AP Photo/Gregory Bull)
By PETER SVENSSON
The Associated PressThe Associated Press
NEW YORK Apr 14, 2005 — If a time traveler from a hundred years ago were to visit a home today, much of the technology would be completely alien. The television, cordless phone and computer would probably leave him flabbergasted.
But on seeing a light bulb, he might say, "Ah! Here's something I recognize. A few of those grace my home, too."
If the visitor comes back in 15 years, the fruit of Thomas Edison's bright idea may be gone. The likely replacement: light-emitting diodes, or LEDs.
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Current white LEDs will last up to 50,000 hours, about 50 times as long as a 60-watt bulb. That's almost six years if they're on constantly.
That makes them attractive for places where changing bulbs is difficult or expensive like on the outside of buildings or in swimming pools. Osram Sylvania, the lighting subsidiary of German manufacturer Siemens AG, makes 27-foot long strips of flexible, adhesive tape covered in LEDs for such applications.
Hotels are interested in using LEDs in bedside lamps to save them the trouble of replacing burned-out bulbs, said Jim Anderson of Lamina Ceramics, which showed off a 6-watt array of LEDs that produce light equivalent to a 20-watt halogen bulb.
LEDs are also durable. Being solid-state, they can resist the vibrations in aircraft and cars, according to Narendran, who has worked with Boeing Co. on designs for aircraft cabins.
General Electric Co. and smaller iLight Technologies of Evanston, Ill., make glowing LED signs that look like neon.
Neon lighting is a leading cause of fires at restaurants and the signs are vulnerable to vandalism. By contrast, LED signs made of Plexiglas are tough. At the trade show, iLight exhibited an LED sign that still worked after taking a blast from a shotgun.
The limitation: iLight's signs can't be made economically on a one-off basis, as done at small neon-sign shops around the country.
The feature of LEDs likely to propel them into homes is aesthetic, not practical. Arrays that mix red, green and blue LEDs can produce any color of the rainbow. Instead of a dimmer, you might have three sliding knobs that let you mix color.
"On a very hot day you might want blue light to cool it down a bit, or on a winter day you may want to simulate sunlight," said Steve Landau of Lumileds Lighting, an LED-making joint venture of Agilent Technologies Inc. and Philips Lighting.
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Qantas Airways Ltd., the Australian airline, recently outfitted its first-class cabin with LED lighting that shines a deep blue when it's time to sleep.
A system like that would be too expensive for most homes, but industry experts believe the price will come down in a few years as the technology develops.
"We are still in a very young research environment," said Norbert Hiller, vice president at Cree Inc. of Durham, N.C., which produces blue and green LEDs. "Our researchers keep surprising us."
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