| 摘要 |
PURPOSE:To increase the luminous efficiency of a high pressure sodium lamp and inhibit suppression of ignition by charging the emitter tube with sodium vapor, mercury vapor and xenon at a xenon partial pressure of at least 130V so that the ignition suppression voltage becomes at most 180V for a lamp voltage of at least 130V. CONSTITUTION:An emitter tube 3 made of a translucent ceramic member and installed in the outer bulb 1 of a high pressure sodium lamp is charged with sodium vapor, mercury vapor and xenon with a xenon partial pressure of at least 300Torr so that the ignition suppression voltage becomes at most 18V for a lamp voltage of at least 130V. And, the load applied to the wall of the emitter tube 3 during lighting is adjusted to be within the range of 15-30W/cm<2>. Therefore, the maximum luminous efficiency of the lamp can be increased by reducing the loss of heat caused by conduction by increasing the partial pressure of xenon gas. Furthermore, it is possible to prevent suppression of ignition by reducing the restrike voltage. |
