Quartz glass arc tube and pinch seals for an arc discharge lamp

摘要

An arc tube has a pair of molybdenum foils (12) that pinch sealed at both ends with a spherical portion (4a) of quartz glass tube in between. The surface roughness of the molybdenum foils and the glass tube is no less than 1 micro m (reference of 0.08 mm) at a ten point average roughness. An Independent claim describes a method for fabricating the tube such that the gas pressure in the tube is 100 torr or less. Preferably the pinch seal is heated to 2000-2300 deg C.