| 摘要 |
PURPOSE:To enable desired rising characteristics to favorably last over a long period by using a high-melting-point metallic material as a base body to be coated with an indium film. CONSTITUTION:An auxiliary amalgam 20 is installed between a filament 17 and the opening of a fine tube 18. The auxiliary amalgam 20 is prepared by coating a base body 21 consisting of high-melting-point metallic foil with a thin indium film 22 by plating, vapor deposition or similar method. Therefore, even when the auxiliary amalgam 20 is heated to high temperature, due to the high melting point of the base body 21, the base body 21 is maintained stable and almost no alloying reaction proceeds between the base body 21 and the indium film, thereby suppressing the thickness decrease and the deterioration of the indium film. Consequently, it is possible to favorably continue desired rising characteristics of luminous flux until the last stage of the life of the lamp. |
