| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrode for a discharge lamp that has a little loss of emitter by evaporation wearing even for a long-term operation. SOLUTION: A tip of a cathode 4 is cone-shaped and has a hole 7 from its tip part to an interior of the cathode with gradually reducing diameter toward the tip. An emitter containing layer 8 comprising a mixture of powders of the emitter and a high melting-point metal has been packed in the hole with increased density as coming closer to the tip, and sintered. The manufacturing method has the following processes: First, the hole is formed at the tip face of the cathode by machining and the mixed powder of the emitter and a high melting-point metal is pressed into the hole. Then sinter processing is conducted, followed by machining a tip face 42 of the cathode into the prescribed cone shape. It is further swaged by means of a metal member having a cone-shaped concave bottom corresponding to the cathode tip.
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