| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of lighting a discharge lamp under a suitable condition. SOLUTION: In this discharge lamp lighting device, when starting a metal halide lamp HID, if the voltage of a capacitor C3 rises and reaches a break-over voltage, a trigger element Q3 is switched on, and if it exceeds the dielectric breakdown voltage of a gap element 34 by inducing a voltage in a secondary winding Tr1b, it is raised by a choke coil 12, and a high voltage starting pulse is given to the metal halide lamp. If the metal halide lamp is lighted, the capacitor C3 gets no more charging and the operation of a start-up circuit 31 stops. A light emitting diode LED does not generate light, a timer circuit 33 measures a constant by switching off a photo-transistor Q2, a control driving circuit 25 controls a lamp current at a relatively high current, and after a certain time has elapsed, the control driving circuit 25 lowers it down to a further lower current by changing the frequency of a means of lighting. |
