| 摘要 |
PROBLEM TO BE SOLVED: To prevent the breakage of circuit components or ignition during discharge by arranging a mechanism which always monitors lamp voltage during lighting of a high-pressure discharge lamp and displays power supply stoppage or abnormality when abnormality is detected. SOLUTION: DC current is supplied to a lighting main circuit 2 having a current limiting function and an adjusting function, such as constant power control from a DC power source 1, and a short arc high-pressure discharge lamp 4 is started through a starting circuit 3. A lamp voltage monitoring means 5 always monitors lamp voltage, a detection output is sent to an abnormality judging means 7, a stable lighting recognition means 6 recognizes that the high-pressure discharge lamp 4 has moved to stable lighting, and permits the abnormality judging means 7 to make judging operation to, and when the lamp voltage after lighting is lowered compared to the specified value, the abnormality judging means 7 judges it as being abnormal, and a control means 8 stops power supply from the lighting main circuit 2 to the high-pressure discharge lamp 4 or displays abnormality. Generation of slow leak in the high pressure discharge lamp 4 is surely detected, and damage in circuit components or ignition is prevented. |
