| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device avoiding a phase advancing action, mitigating the overload of an inverter, and making a smooth shift to the lighting mode. SOLUTION: Preheating start frequency fa, ignition frequency fb, full lighting frequency fc, and dimming frequency fd are all set higher than the preheating resonance frequency before the ignition of the discharge lamp of a resonance circuit so that full lighting frequency fc < ignition frequency fb < dimming frequency fd. When a lighting device is set to the fully lighting mode, a shift is made in the order of the preheating start frequency fa, ignition frequency fb and dimming frequency fd. The discharge lamp is temporarily lighted at the ignition frequency fb in any case, then a shift is made to the fully lighting frequency fc slightly lower than the ignition frequency fb or the dimming frequency fd slightly higher than the ignition frequency fb. The brightness change caused by the last shift is slight. |
