High pressure metal vapor electric-discharge lamp

Abstract

Abstract PURPOSE:To enable an arc fluctuation to be effectively prevented by making the inner diameter of the center part of an emission tube larger than that of its ends, and adjusting the ratio of the length (l) of the thickened part to the distance (L) between electrodes to within the range of 0.2-0.8. CONSTITUTION:When an electric discharge lamp having an emission tube the center part of which is thickened is suppressed, mercury contained in the emission tube congeals in larger amount in the center part of the emission tube than in its ends. Owing to such a phenomenon, when a once suppressed lamp is lighted again, an arc fluctuation is effectively prvented since the density of mercury is higher in the center part than in the ends of the emission tube. In addition, by adjusting the relationship between the length (l) of the center part and the distance (L) between electrodes to within the range of 0.2<=l/L<=0.8, the rated life can be accomplished with causing almost no arc fluctuations.

Inventors

• 👤 Katsuhiro Kawai
• 👤 河合　勝弘

Bibliographic Details