Patent ID: 7141932
Filing Date: 2006-11-28
Classification: H01J

Abstract:
1. A metal halide lamp comprising: a hermetic vessel which is fire resistant and translucent; a pair of electrodes sealed in the hermetic vessel facing each other at a distance of 5 mm or less; and a discharge medium substantially containing no mercury, sealed in the hermetic vessel, and containing first halides mainly including scandium halide and sodium halide, a second halide for mainly providing a lamp voltage, the second halide emitting substantially no visible light, and a xenon gas at 5 atmospheres or higher at a temperature of 25° C., the amounts of scandium halide and sodium halide sealed in the hermetic vessel satisfying the formula: where reference character a denotes the mass of scandium halide and reference character b denotes the mass of sodium halide, in a stable state, the metal halide lamp is turned on with a lamp power of 60 W or lower; and wherein the second halide comprises one or more halides of metals selected from among Mg, Co, Cr, Zn, Mn, Sb, Re, Fe, Al, Ti, Zr, and Hf.