| 摘要 |
PURPOSE:To provide good lighting performance by sufficiently long taking a period, in which a lamp current flows after applying a high voltage pulse, so as to facilitate establishing an arc discharge, in a lighting device for starting an electric discharge lamp by applying the high voltage pulse overlapped with stationary device voltage to the electric discharge lamp. CONSTITUTION:In an inverter 3, rectangular wave AC voltage of prescribed frequency is generated. In an igniter circuit 9, a capacitor C2 is charged in each half cycle of negative polarity of this rectangular wave AC voltage. In the point of start time in each half cycle of positive polarity of the rectangular wave AC voltage, a thyristor Q is ignited, and a charge of the capacitor C2 flows in a primary coil L21 of a pulse transformer PT, to generate a high voltage pulse in a secondary coil L22. This high voltage pulse is overlapped with the head part of a half cycle of positive polarity and applied to an electric discharge lamp 12. In the electric discharge lamp, a lamp current is started to flow, by applying the high voltage pulse, and continued to flow over a total period of the half cycle of positive polarity, and as a result, an arc discharge is established in the electric discharge lamp 12 to arrive at lighting it. |
