| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to detect no lighting of a lamp due to the breakage of the lamp so as to distinguish no lighting of the lamp due to a high temperature in a device for lighting the lamp as an illuminating light source for a liquid crystal projector or the like. SOLUTION: When a power supply is turned on, a timer 11 is set and an ignitor 13 is driven. When the lamp 1 is not turned on, an output signal Du from a lighting/no-lighting detection circuit 31 is turned to a high level. When the lamp 1 is broken, an output signal Tb from the timer 11, the output signal Du of the circuit 31 and an output signal Dt from a temperature detection circuit 33 are turned to high levels immediately after a driving period set by the timer 11 and an output signal Da of an AND circuit 34 is turned to a high level, so that the breakage of the lamp 1 can be detected. Since an LED 39 is turned on at the time, a user can know the breakage of the lamp 1. COPYRIGHT: (C)2003,JPO |
