| 摘要 |
PURPOSE:To provide a metal halide lamp with low starting voltage and good optical flux maintainability rate by setting the hydroxyl group content of the molding work section of quartz that forms a luminous tube to less than 10ppm. CONSTITUTION:A small diameter quartz tube 18 and an intermediate diameter quartz tube 19 are heated and softened by a burner and are molded and worked in a tapered shape. Then after these are joined with each end of a large diameter quartz tube 20, an exhaust tube 21 is joined to the central part and a quartz tube (luminous tube bulb 22) with a shape shown in Figure d is obtained. After this luminous tube 22 is heated and processed for 8hr at 1,075 deg.C under the argon atmosphere, a preset amount of iodide such as sodium, thallium, or indium is entered in the inner part and is exhausted under vacuum, a preset pressure of neon-argon mixed gas is sealed and a luminous tube 1 shown in Figure (e) is completed by chipping on an exhaust tube 21. The hydroxyl group content of the molding work sections 2a and 2b of this luminous tube is set to less than 10ppm and the moisture content discharged in the luminous tube is reduced while a lamp is lighting and the lamp with low starting voltage and good luminous flux maintainability rate is obtained. |
