| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp that realizes a long lifetime and high stability, equivalent to those of one using a thorium tungsten electrode that does not use thorium in an electrode material, as to one of a high load and at high luminance. SOLUTION: A cathode and an anode are arranged, facing inside an encapsulated arc tube, of which the cathode is made of tungsten containing at least one oxide of a group of metal consisting of lanthanam, cerium, gadolinium, and yttrium, and is provided with at least one substance from among a group of zirconium, zirconium oxide, zirconium carbide, hafnium, hafnium oxide, and hafnium carbide, a tungsten carbide layer at least at a part of the outer surface of the cathode, excluding its tip part, and a hydrogen storage body storing hydrogen inside the arc tube. Additionally, the hydrogen storage body is, preferably, constituted of either tantalum, niobium, or zirconium as hydrogen storage material. COPYRIGHT: (C)2010,JPO&INPIT
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