| 摘要 |
PROBLEM TO BE SOLVED: To detect that the light quantity of a light emitting source is changed in the lapse of time and to automatically correct the light quantity of the light emitting source in a short time. SOLUTION: After respectively comparing 1st, or 2nd detection data held by each data storing means 33 and 34 and 1st, or 2nd detection data detected by a part for detecting the light quantity of the light source 22 and a reflected light quantity detecting part 23, the fluctuation states of the emitted light quantity and the reflected light quantity are decided by a take-in value deciding part 35. After correcting the emitted light intensity value by a emitted light intensity setting means 36 based on the decision results, the emitted light intensity value corrected and set is converted to a voltage signal by a D/A converter 24, then, a constant current based on the converted voltage signal is impressed on the light emitting source 21 by a constant current circuit part 25 so as to control the emitted light quantity. |
