| 摘要 |
PURPOSE:To stably restart each discharge lamp and reduce flickering of each lamp and stabilize color luminescence by making a voltage higher during the stopping period than during the lighting period of each discharge lamp when applying the voltage to the series circuit of each discharge lamp and each switching element. CONSTITUTION:Frequencies at which switching elements S4, S5 are turned on and off are set by an inverter driving circuit 4 in such a manner that a frequency f1 for use during the lighting period of each discharge lamp L1 to L3 is higher than a frequency f2 for use during the stopping period of each discharge lamp. The frequencies at which time elements S4, S5 of the inverter circuit 1 are turned on and off are varied during a fixed stopping period in which all of elements S1 to S3 connected in series to the respective discharge lamps L1 to L3 are turned off before being turned on, so as to heighten the output voltage of the circuit 1. Thereby a voltage required for restarting can be applied to each discharge lamp L1 to L3 and discharge would not become unstable at the restart of each discharge lamp L1 to L3. |
