Patent ID: 6353289
Filing Date: 2002-03-05
Classification: H01J,H05B,Y02B

Abstract:
A metal halide discharge lamp which essentially permits disusing mercury, comprising:(a) a refractory and light-transmitting hermetic vessel; (b) a pair of electrodes fixed to said hermetic vessel; and (c) a discharge medium sealed in the hermetic vessel and containing a first halide, a second halide, and Xe gas, (i) said first halide being a halide of at least one metal selected from the group consisting of sodium, scandium, and a rare earth metal, (ii) said second halide having a relatively high vapor pressure so as to act as a buffer gas to maintain a lamp voltage and being a halide of at least one metal which emits a visible light less than that emitted by the metal of the first halide, and (iii) said Xe gas being sealed in a pressure of at least one atmosphere; wherein a combination of said first halide, second halide, and Xe gas sealed in the hermetic vessel causes light emitted from the metal halide lamp to fall within a range of chromaticity of white color immediately after lighting.