| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in a simple structure for properly preheating a discharge lamp. SOLUTION: A direct current from a DC power supply E is transformed into a high frequency current by an inverter circuit 11 to preheat filaments FL1a, FL1b. In such a state, a discharge detecting circuit 12 does not form a DC closed circuit, so that a direct current is not applied to a capacitor C3 and the capacitor C3 is not charged. When a fluorescent lamp FL1 is discharged and lit, the DC component is applied to the capacitor C3 and, when voltage is higher than a reference power supply E1, the fluorescent lamp FL1 is judged to be discharged and lit. When discharge is detected in a preheating required condition, the output of the inverter circuit 11 is decreased by negative feedback and the filaments FL1a, FL1b are preheated again by glow discharge. After they are sufficiently preheated, the voltage of the reference power supply E1 is increased by using a timer and the output of the inverter circuit 11 is increased to start and light the fluorescent lamp FL1. |
