| 摘要 |
PROBLEM TO BE SOLVED: To perform a safe operation by reliably detecting an end of a lifetime of a discharge lamp. SOLUTION: A temperature fuse 4a to open a filament circuit by detecting an end of a lamp lifetime by a temperature in the neighborhood of the filament in an arc tube bulb is provided in a discharge lamp 4, on the other hand, a detecting part 5 to reduce or stop an output of an inverter circuit 3 by detecting the end of the lamp lifetime by half-wave discharge of the discharge lamp 4, and a safe operation is performed by either one of the above operations. |
