High luminance electrodeless projection lamp

摘要

An Electrodeless High Intensity Discharge (EHID) lamp for projection applications. The lamp has a small (nominal dimensions: 2 mm I.D., 3 mm O.D., 6 mm internal length) capsule, which is constricted in a mid-portion thereof. The constriction squeezes the plasma within the capsule and provides a higher power density. This in turn produces a higher luminance in the center of the arc. This focal point of the projection system is constant over the life of the lamp, owing to the fact that the system is electrodeless. The arc tube or capsule is thickened in the vicinity of the constriction to permit heat transfer through the vitreous silica (commonly called quartz). The thickening carries the heat away from the now hotter mid-portion area. This thickening cools by virtue of increasing the thermal conduction through the glass.