| 摘要 |
PURPOSE:To prevent the deterioration of the lamp life by soft-starting a hot cathode type discharge lamp in response to the ambient temperature. CONSTITUTION:When the operation of a high-frequency generating device 1 is started for starting a discharge lamp 2, the output voltage of the device 1 is made lower than the starting voltage of the discharge lamp 2 by a soft-start circuit 3. After it is preheated for a preset time under this condition, the voltage of the starting voltage or above is outputted for lighting. When the temperature of the discharge lamp 2 is higher than its ambient temperature, a temperature sensing device 4 senses the ambient temperature and controls the circuit 3, thereby the voltage lower than that at the ordinary temperature is outputted by the device 1. The discharge lamp 2 is lighted after being preheated for the same time as for the ordinary temperature. When the ambient temperature is higher, preheating is performed with the lower output voltage than that for the ordinary temperature, then the discharge lamp 2 is lighted. A soft-start is performed in response to the ambient temperature, thus a cold-start can be prevented even when the ambient temperature is high and the discharge lamp is easily lighted, and the deterioration of the lamp life is suppressed. |
