| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting device capable of detecting precisely the end of lifetime of a fluorescent lamp. SOLUTION: In the lighting device having a fluorescent lamp as a light source, a detection circuit is provided in which a first voltage showing a peak value of a positive potential and a second voltage showing a peak value of a negative potential are respectively detected regarding the voltage across both ends of the fluorescent lamp at the time of lighting of the fluorescent lamp, and the difference in the absolute values of the first voltage and the second voltage is obtained, and it is decided whether or not the difference is within a prescribed range, and if it is decided that it is not within the prescribed range, a detection signal is output. COPYRIGHT: (C)2009,JPO&INPIT |
