Incandescent light bulbs may have a bright future after all
By Alan Brandon
July 15, 2009
In the face of legislation being enacted around the world, the future of the trusty incandescent light bulb has been looking dim. Ireland has banned the sale of incandescent bulbs, and the United States is set to phase them out by 2012. And it’s no wonder -- the apple of Thomas Edison’s eye is something of an energy hog, especially when compared with modern bulbs such as compact fluorescent (CFL) bulbs and LED-based lights. But now a new technology from Deposition Sciences Inc of Santa Rosa, California, is promising a brighter future for the venerable incandescent.
The New York Times reports that Deposition Sciences, a producer of optical thin-film coatings, has developed an enhanced silver coating that it says provides superior reflector performance and increased lumen output. In a traditional incandescent bulb, only a small portion of the energy used is converted into light. The rest is emitted as heat. In the new bulb design, the Deposition Sciences coating is applied to a gas-filled capsule that surrounds the bulb’s filament. The coating reflects heat back to the filament, where a portion of it is transformed into additional light.
The first of these new bulbs to reach consumers are Philips Lighting’s Halogena Energy Savers. While more expensive than traditional incandescent bulbs, the Halogena Energy Savers are 30% more efficient. Philips says its 70-watt Halogena Energy Saver produces the same amount of light as a traditional 100-Watt bulb and lasts about three times as long.
Deposition Sciences says it has already achieved a 50% increase in efficiency in the laboratory, and hopes a lighting manufacturer will bring this latest technology to market soon.
Other developments in incandescent bulb technology include research at the University of Rochester using lasers to pit the surface of the tungsten filament, and work at Rensselaer Polytechnic Institute that employs an iridium-coated filament that recycles wasted heat.