| abstract |
(57) [Abstract] [Purpose] A metal vapor discharge lamp containing iron, thallium, and bismuth was loaded at a load of 1 cm 2 on the inner wall of the arc tube. When the light is turned on at more than 58 W / cm 2 over W / cm 2 , the thin film of iron is prevented from being formed by the action of thallium, and thallium is uniformly distributed in the tube axis direction. [Arrangement] Mercury, noble gas, iron, halogen, thallium, and bismuth are enclosed in the arc tube 1, and the arc tube inner wall is 1 cm. The load per 2 beyond the 25W / cm 2 58W / cm Turn on at 2 or less. Then, the gram atom number ratio (Bi / Tl) of bismuth to thallium is set to 1/8 to 5/1. More preferably, the sum of the number of gram atoms of thallium and bismuth is 2 × 10 per volume of 1 cm 3 in the arc tube 1. -8 to 2.5 × 10 -7 . |