Kyoto, Japan —Engineers at Panasonic are claiming an electrodeless lamp will last as much as 10×longer than conventional lamps, yet measures 10×smaller than other electrodeless designs. The new lamp's improved efficiency and overall characteristics of emitted light, they say, are the result of two design features: 1) use of indium-halide (InX) as the emission material, and 2) deployment of a vane-type resonator as the energy supply.
"Conventional electrodeless lamps use a cavity type resonator to discharge the energy," says Akira Hochi, a researcher at Panasonic's Lighting Research Laboratory. "Cavity resonators tend to be large because it is hard to concentrate microwave energy into a small space." The company claims the size of the luminous element used to create light in the electrodeless vane-type resonator is 3 mm as opposed to 30 mm for a cavity resonator.
Indium-halide proved to be the best gas to produce white light practical for projection. "An electrodeless sulfur lamp emits a strong continuous spectrum with a peak wavelength of around 500 nm," explains Hochi. "It is highly efficient but it produces a greenish white light not suitable for lighting in general." Tungsten or rhenium metal clusters have also been used in previous lamp designs because of high rendering properties. However, in these lamps the light reproduction is inefficient as they can only operate under narrow plasma temperature conditions.
Indium-halide, Hochi says, produces peak wavelengths of 410 and 451 nm that produce a strong blue emission. "We found, however, that when powered with a microwave, it produces a light with high color-rendering properties close to natural sunlight."
The company plans to release the product in 2002 and to market the lamp for fiber-optic applications, spotlight design, and LCD camera projection.