| 摘要 |
PURPOSE:To extinguish the end glow by providing an operation stopping device temporarily stopping the operation of a high-frequency generator in response to the pulse signal and a pulse signal blocking device blocking the feed of the pulse signal to the operation stopping device while the lighting signal is fed. CONSTITUTION:When the lighting signal is fed, a lamp L is instantly lit, a high-frequency generating circuit F continuously feeds the lighting power and the preheating power while the signal is fed, and the lamp L continues to be normally lit. On the other hand, when there is no lighting signal, the lamp L is turned off, the preheating current flows during this time, the high-frequency generating circuit F is temporarily stopped in response to the pulse signal while the lamp L is turned off, and the heating current is temporarily stopped. Arcs are ignited on filaments L1 and L2 to form the end glow immediately after the lamp L is turned off, the end glow is extinguished when the next preheating current is stopped, and no re-ignition occurs because ions already disappear when the next preheating current flows again. Since the continuing time of the end glow is very short, the blocking caused by the end glow can be prevented. |
