| 摘要 |
PROBLEM TO BE SOLVED: To realize a uniform starting characteristic in spite of errors in production, when electric power larger than the rated electric power is supplied in the time of starting of the discharge lamp to secure the sufficient amount of light from just after the starting, in the time of the constant power control of the lamp. SOLUTION: A microcomputer circuit 21 stores detected lamp voltage at the time of stable lighting of the high-pressure discharge lamp 7 in an EEPROM 29, in every lighting. During initial phases of the operating, if the lamp voltage is lower than, for example, 68V, the microcomputer circuit 21 controls a lighting circuit 5 to supply electric power larger than the rated power to the high- pressure discharge lamp 7. In this case, a CPU 26 of an arithmetic circuit 22 reads the detected lamp voltage in the time of the previous lighting from the EEPROM 29. And the CPU 26 looks up a data table stored in a ROM 27 to regulate a load characteristic of the high-pressure discharge lamp 7, according to the lamp voltage read in from the EEPROM 29. |
