HIGH-PRESSURE VAPOR DISCHARGE LAMP

摘要

PROBLEM TO BE SOLVED: To prevent elevation of a lamp voltage and evaporation of an alumina tube during the life, and realize the safe and stable property of a lamp without the breakage of outer tube in a high-pressure vapor discharge lamp in which a light translucent ceramic tube is used for a light emission tube and in which the rated lamp electric power is 220 W to 250 W. SOLUTION: This is the high-pressure discharge lamp in which a light emission tube made by light translucent alumina is incorporated in a glass outer tube wherein the inner part pressure is maintained at 0.2 Pa or less, and which has a structure wherein a glass pipe is installed whose thickness is 1.4 mm to 1.8 mm in order to surround all the side faces of the light emission main tube between the outer tube and the light emission tube, in which the rated lamp electric power Wt of the high-pressure discharge lamp is 220 W<=Wt<=250 W, and in which the maximum outer diameter of the light emission tube is 15 mm to 18 mm and the inner diameter of the glass pipe is 24 mm or more.