| 摘要 |
PROBLEM TO BE SOLVED: To provide a state judging method of a discharge lamp which is little restricted by the types of filament and which is easy to measure. SOLUTION: The discharge lamp 8 is glow-discharged and a lamp voltage value is detected at that time. Then, deterioration state of the discharge lamp is judged according to this lamp voltage value. For example, when the lamp voltage value exceeds a previously set prescribed value, the discharge lamp is judged to have come to the end of life. Moreover, by informing the result by displaying it and by reducing or stopping output of a lighting device 2, inconveniences caused by the fact that discharge lamp at the terminal period of life continues lighting are prevented. COPYRIGHT: (C)2007,JPO&INPIT |
