The Green (and blue, red, and white) lights of the future

Dec 17, 2008

A revolution in energy-efficient, environmentally-sound, and powerfully-flexible lighting is coming to businesses and homes, according to a paper in latest special energy issue of Optics Express, the Optical Society's open-access journal.

The paper envisions the future of lighting -- a future with widespread use of light emitting diodes (LEDs), which offer a number of obvious and subtle advantages over traditional light bulbs.

"We are at the verge of a revolution," says the paper's senior author E. Fred Schubert, a professor of electrical engineering and physics at Rensselaer Polytechnic Institute in Troy, NY. "There are tremendous opportunities that open up with LED lighting."

LEDs are more rugged, resembling something closer to hard plastic than thin glass. They are also more environmentally sound, since their manufacture does not require toxic substances such as mercury.

As an alternative to the traditional incandescent light bulb, LED lights provide significant energy savings. They can be 2,000 percent more efficient than conventional light bulbs and 500 percent more efficient than compact fluorescent bulbs. Schubert predicts that widespread use of LEDs over the course of 10 years would save more than $1 trillion in energy costs, eliminate the need for nearly a billion barrels of oil over 10 years, and lead to a substantial reduction in emissions of carbon dioxide, the most common greenhouse gas.

All of these advantages make LEDs a good replacement light source, says Schubert, adding that this is why there has been a tremendous recent expansion of the LED industry, which is growing by double-digit rates. However, he adds, the true potential of LED lighting lies in their ability to transform -- rather than simply replace -- lighting technology.

"Replacement is fine," says Schubert. "But we must look beyond the replacement paradigm to see the true benefits of LED lights." Schubert envisions a day when light switches give way to light switchboards that control not only the brightness of a light, but its color temperature and hue. Light spectra could be custom-tailored for all wavelengths, accurately matching the sun's light qualities and vary these characteristics according to the time of day, for instance. This could revolutionize indoor agriculture and help night-shift workers and people who are jet-lagged. The use of polarized light from LEDs could also improve computer displays and lower the glare from car headlights.

In his article, Schubert lays out how such future, "smart" light sources, can harness the huge potential of LEDs.

Paper: "Transcending the Replacement Paradigm of Solid-State Lighting," E. Fred Schubert and Jong Kyu Kim, Optics Express, Vol. 16, Issue 6, December 22, 2008, Focus Issue on Solar Energy edited by Alan Kost, University of Arizona.

Source: Optical Society of America

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User comments : 5

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5 / 5 (6) Dec 17, 2008
Hopefully people will "warm up" to LED lighting sooner rather than later! :)
3.7 / 5 (6) Dec 17, 2008
"...accurately matching the sun's light qualities and vary these characteristics according to the time of day, for instance."

People have made it abundantly clear that they don't want this. They want the irritating dull orange/yellow 2700 K lighting of incandecent lighting.

Concentrate on imitating incandecent lights first and then branch out to niche products over time.
3.8 / 5 (4) Dec 17, 2008
Hopefully people will "warm up" to LED lighting sooner rather than later! :)

Standard sized fluorescent lighting never took off in the consumer market because it couldn't fit into regular E-13 and E-27 screw sockets. CFLs managed to grab a little bit of market share, but are limited by the high cost of initial purchase(even though they provide decent cost savings over their life for any light source used a significant amount of time) and lack of dimming.

Make them cheap, annoying 2700 K orange-yellow and fitting into standard sockets and people will buy them. Until you can do that(or if you ban incandecent lighting, until you can compete in those respects with CFLs) LEDs are going to keep losing.
4.3 / 5 (3) Dec 17, 2008
And not a moment too soon. But I must agree that I've gotten used to the warm glow of incandescents, and wouldn't gladly switch to coldly efficient alternatives.
5 / 5 (3) Dec 17, 2008
As the article pointed out, tunable lighting is relatively easy with LEDs. I'd love to have one that produces solar-spectrum light for working, reading, and taking pictures. The "warm" incandescent light is closer to dusk or dawn, and would be perfectly suited for relaxing activities. If the same bulb could produce both, even if it was simply a two-position switch, that would be ideal.

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