| 摘要 |
PURPOSE:To enable the setting of heating power suitable for each discharge lamp without any influence upon a resonance condition and prevent interference between discharge lamps in a luminous condition. CONSTITUTION:An electrode F used as a heater in common for a discharge lamp 1 lighting on an inverter system, is separately provided with a high frequency power supply circuit via diodes 8 and 9 having rectifying directions different from each other. The aforesaid power supply circuit is provided with a capacitor 7 for a current limiting element. Consequently, preheating power is adjusted without any influence upon a high frequency oscillation circuit C via the adjustment of the capacity of the capacitor 7 for each discharge lamp 1. Also, interference between the discharge lamps 1 is prevented in a luminous condition resulting from the selection of a switch 10 after preheating and connecting the electrode F to an inductor 3. According to the aforesaid construction, the supply of preheating electric power is optimally adjusted without any influence upon a resonance condition for each discharge lamp to be selected between preheating and lighting with a single switch. Interference between the discharge lamps in a luminous condition is thereby prevented. |
