Ultra high luminance (UHL) lamp with SCA envelope

摘要

An Ultra High Luminance (UHL) high intensity discharge (HID) lamp is described. The lamp envelope is made of single crystal alumina (SCA) material. The fill consists mainly of mercury at densities in the range of 0.3 to 0.7 mg/mm³. The lamp is designed for applications in the projection field where small light modulation imaging devices are used. The lamp design includes a variety of burner (lamp vessel ) geometries and sealing arrangements. This lamp technology represents a major departure from the Ultra High Pressure (UHP) fused silica envelope, mercury filled, HID lamps that are currently used and overcomes the adverse effect of convection. The preferred, and described, alternative burner (vessel ) geometries are envelopes with non-uniform wall thickness, which are thicker at the tops and thinner at the bottoms; a bulbous shape which is more curved at the top than at the bottom; and placing the arc off the center axis, so that the arc is closer to the bottom than it is to the top. The vessel, preferably, is manufactured as a monolithic SCA crystal so that traditional end plugs are not needed.