High-pressure metal vapor discharge lamp with characteristic fuse action

摘要

A high-pressure metal vapor discharge lamp comprising an outer tube, a light emitting tube located within the outer tube and made of a light-transmissive ceramics material, and a fuse electrically connected in series with the light emitting tube, in which said fuse has such a blowing characteristic as given by the following equation and at a rated output during the lighting of the lamp the density of a current through the fuse is not more than 23.9 A/mm2: log T1<AlogI+B A=-1.02x10-2(D2t)-0.885 B=2.64x10-2(D2t)+1.01 T: required blowing time (seconds) of the fuse I: blowing current (A) of the fuse D: inner diameter (mm) of the light emitting tube t: wall thickness (mm) of the light emitting tube.