| 摘要 |
PURPOSE:To switch reliably polarity of high voltage impressed on light emitting tubes, and start the light emitting tubes to be started in prescribed order by operating a high voltage generating device after switching the polarity of the high voltage generated by a switching means. CONSTITUTION:Plural light emitting tubes 71 and 72, a high voltage generating device 9 and a polarity switching means 10 are provided. The light emitting tubes 71 and 72 are arranged in parallel with AC electric power supply 1, and have proximity conductors 81 and 82 connected to polarity different from voltage polarity of the AC electric power supply 1. The high voltage generating device 9 generates high voltage to start selectively the light emitting tubes 71 and 72 in a half cycle in either a positive or a negative of AC voltage, and starts and lights either one of the light emitting tubes 71 and 72, and the switching means 10 switches polarity of the high voltage generated by the high voltage generating device 9. Thereby, operation time of the high voltage generating device 9 and the switching means 10 is controlled in such the relationship as the high voltage generating means 9 outputs the high voltage after polarity switching is completed by the switching means 10. |
