MICROFABRICATED HIGH-INTENSITY DISCHARGE LAMPS

Miniaturization of high intensity discharge lamps can lead to cheaper, more efficient, and novel lighting systems for the lighting industry. We are applying micromachining and techniques used for manufacturing integrated circuits, to develop such miniature lamps. We have fabricat ed electrodeless and electroded high-pressure mercury discharge lamps in quartz substrates using integrated circuit and micromachining techn iques, such as photolithography, etching, and wafer bonding. Patterned quartz wafers were bonded together using fusion wafer bonding. The re sulting cavities are strong enough to withstand the high pressures (12 4 atm) and high temperatures (1000 degrees C) in these lamps. Lamps co ntaining varying amounts of mercury were fabricated to obtain high-pre ssure discharges in the range of 10-175 atm. The electrodeless lamps w ere excited by a microwave source, operating at 2.45 GHz and the elect roded lamps with a dc voltage. Lamp efficacies over 40 lumens (lm)/W w ere obtained for the electrodeless lamps and over 50 lm/W for the elec troded lamps. These results demonstrate that high-pressure mercury dis charges can be sustained in the lamp cavities formed by micromachining techniques. In addition, these cavities are not only hermetically sea led, but can also withstand the high-pressure and high-temperature env ironment of high-pressure mercury discharges. (C) 1997 American Vacuum Society.