| 摘要 |
PROBLEM TO BE SOLVED: To prevent damage on an anode when lighting up in a short arc type discharge lamp having the anode wherein a front zone for receiving electron collision is made from tungsten and a rear zone for not receiving electron collision is made from molybdenum.SOLUTION: In the short arc type discharge lamp wherein the anode 7 and a cathode 8 are oppositely arranged in a light-emitting tube, a head 71 of the anode 7 at a side opposite to the cathode 8 is made from tungsten, and a body 72 continued to the head 71 is made from molybdenum. A ring-shaped or a plurality of projections 71a', 71b', and 71c' are formed on a joint surface at ahead side of the joint surfaces of the head 71 and body 72, and the joint surface at a body side is formed to surround the projections 71a', 71b', and 71c'. Damage on the anode 7 can be restrained since thermal stress acting on the tungsten zone of the head 71 meshed with the molybdenum zone of the body 72 or the molybdenum zone of the body 72 meshed with the tungsten zone of the head 71 is relieved. |
