| 摘要 |
PURPOSE:To attain high efficiency of a metal vapor electric-discharge lamp, which contains a heat insulating film provided at the end of an emission tube, by adjusting the molar ratio of a sodium halide to a scandium halide charged in the emission tube within the range of 6-40, and selecting the height of the said heat insulting film of a main electrode. CONSTITUTION:The amount of scandium iodide charged into an emission tube 1 is adjusted to 9mg constantly. The molar ratio of sodium iodide to scandium iodide charged into the tube 1 is adjusted within the range of 6-40. In addition, the ratio H/L of the height H of a heat insulating film to the length L of a main electrode protruding from the bottom surface of the sealing part is adjusted within the range of 1.2-3.2. As a result, the efficiency of the lamp is enhanced. |
