<title>Short-arc metal halide lamp suitable for projector application</title>

Abstract

Recently, progress has been made in the development of projectors used for large screen displays. Projection systems employing high luminous efficiency Metal Halide Lamps as a light source demonstrate unique and desirable features. For example, compared to conventional lamps, a Metal Halide Lamp has longer life, higher luminous efficiency, the shortest arc length possible, and higher color-rendering characteristics, resulting in an overall superior performance. Several lamps, including Metal Halide, Xenon, and Halogen lamps, are used in HDTV (High Definition Television). Recently, Metal Halide Lamps have become accepted as the light source of choice. The reason for this is the high brightness, color balance, and long life of the Metal Halide Lamp. The fundamental operating principal for Metal Halide Lamps is almost the same as that of Mercury lamps. A Metal Halide Lamp has very different characteristics in that, the spectrum of illumination can be varied by varying the mixture of Metal Halide generated in the lamp. For these lamps, we have improved the electrode, the chemical composition of the Metal Halide, and the glass envelope. We have achieved a longer average life (greater than 2500 hours) for a compact, single-bulb, projection-type lamp.