| 摘要 |
PROBLEM TO BE SOLVED: To prevent the illumination time of a lamp from being misintegrated even if a short-time power failure is repeated. SOLUTION: Integrated illumination time information on a light source 1 is written to a memory 7 in specified cycles. An elapsed time counting circuit 11 counts the elapsed time from the writing timing to power failure timing and when recovery from a power failure is made, the elapsed time information that the elapsed time counting circuit 11 counts is added to integrated illumination time information held in the memory 7. Further, the elapsed time counting circuit counts the elapsed time from the writing timing to the recovery according to power failure time information that a power failure time detecting circuit 10 detects. When the integrated illumination time information reaches a predetermined time set value, a control circuit 6 controls a replacement display circuit 8 to make display urging lamp replacement of the light source 1. Such constitution can prevent the integrated illumination time from being misintegrated even at a power failure. COPYRIGHT: (C)2004,JPO&NCIPI
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