| 摘要 |
PURPOSE:To increase the maximum cooling point of a glow tube, improve the efficiency without increasing the tube wall load, and elminate light and color unevenness by providing a transparent heat screening plate at the lower electrode sealing area at least while it is lighting. CONSTITUTION:A metal halide lamp lights vertically with the metallic cap 14 facing upward, the temperature at the vicinity of the neck area of the outer tube 13 is lower than those of remaining areas. Therefore, the maximum cooling point of the rear electrode area of the glow lamp 1 is cooled due to the convection of inert gas sealed in the outer tube 13, but it is checked by the heat screening plate 11 which is provided at the electrode sealing area 10 and the maximum cooling point is heat-insulated. It is also heat-insulated by the infrared reflection of the heat screening plate 11. |
