| 摘要 |
PROBLEM TO BE SOLVED: To provide a short arc type discharge lamp having a cathode which can prevent illuminance fluctuations by supplying an electron emissive material stably to arc from the tungsten cathode. SOLUTION: The short arc type discharge lamp has a pair of cathode and anode arranged in opposition inside an arc tube. The cathode 20 is made of a tungsten material containing an electron emissive material and has: a taper part 24 which becomes smaller in diameter toward the tip; a tip face 25 formed on tip side of the taper part 24; and a fine hole 26 extending from the tip face through inside the cathode. The fine hole 26 is formed extending over two or more tungsten crystal grains at the tip face. COPYRIGHT: (C)2011,JPO&INPIT
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