METAL HALIDE LAMP

PURPOSE:To provide a metal halide lamp having a light source color having an arbitrary color temperature within a range of 2000-6000K by stabilizing characteristics as a light source adopting a light interference filter films, so as to reduce fluctuation, selecting the metal halide lamp having a high color temperature, and utilizing a color temperature decreasing effect of the light interference filter film. CONSTITUTION:Electrodes 2, 3 are sealed at both ends of a light emitting tube 1, into which dysprosium iodide, neodium iodide, cesium iodide, mercury and argon gas are enclosed. Heat insulating films 4, 5 are formed at the outer surface at the end of the light emitting tube 1. Light interference filter films 6 are disposed at the outer surface held between the heat insulating films 4, 5. The light interference filter film has the two-layer structure, where a first layer is made of tantalum oxide while a second layer is composed of silicon dioxide.