DUAL TUBULAR TYPE METAL-HALIDE LAMP

摘要

PROBLEM TO BE SOLVED: To suppress cracking of a sealing part in a dual tubular type metal-halide lamp. SOLUTION: In the dual tubular type metal-halide lamp, at least a translucent outer tube is arranged so as to surround at least a light-emitting tubular part 11 at the outside of a translucent air-tight container 1 having the light-emitting tubular part 11 that has an electric discharge medium sealed inside, and the air-tight container 1 and the outer tube 7 are mutually joined by dissolving each other's one part, while a relationship between a thermal expansion coefficient a1 of the air-tight container 1 and a thermal expansion coefficient a2 of the outer tube 7 is 1.25≤a2/a1≤1.55. COPYRIGHT: (C)2007,JPO&INPIT