| 摘要 |
PROBLEM TO BE SOLVED: To control to keep an optical output of a discharge lamp almost constant with a simple construction without using a special construction if there is an adaptable lamp having different rated life. SOLUTION: The discharge lamp lighting device comprises a high frequency lighting device 2 for energizing a fluorescent lamp 3; a timer 6 for counting a lighting time of the fluorescent lamp; a nonvolatile memory 7 for cumulatively storing the lighting time counted by the timer; a light control signal generating portion 8 for generating a light control signal having the on-duty controlled based on the cumulated lighting time of the fluorescent lamp stored in the memory and a life time of the rated life set in advance; and a main control portion 9 for controlling lighting of the fluorescent lamp in response to the light control signal at an initial light control level of 70% at first when exchanged, then increasing the light control level gradually in proportion to the increase of the cumulated counted lighting time, and controlling lighting by setting the light control level to almost 100% when the cumulated counted lighting time reaches the rated life time set in advance, wherein a lamp having a rated life almost the same as that of the set rated life time is used for the fluorescent lamp. COPYRIGHT: (C)2006,JPO&NCIPI |
