Metal halide lamps with rare earth additives

Abstract

The construction and characteristics of one particular range of high pressure mercury lamps incorporating halide additives of the rare earths dysprosium and holmium are discussed in the broad context of other halide and high pressure discharge sources. Metal halide lamps with these rare earth additives have high luminous efficacies and excellent colour-rendering properties, making them particularly suitable for applications such as lighting for outdoor colour television where it may be necessary to supplement daylight. After reviewing the principles of operation, the construction and performance of ellipsoidal and linear forms of lamps used for general lighting, high pressure compact source types, and lamps designed for immediate restarting while hot are described, Dimensions and performance data are given.