| 摘要 |
PROBLEM TO BE SOLVED: To suppress the increase of the number of components of an optical scanner and to reduce the cost of the optical scanner. SOLUTION: In an exposure device 120, a laser beam is emitted from a laser diode 10 and a film is scanned in a scanning direction by the laser beam. Photodiodes 17 and 18 are provided on a start point within a scanning range and the photodiodes 17 and 18 detect the level of a light quantity of the incident laser beam and output detection signals of the detected level to a sample-and- hold circuit 24. The sample-and-hold circuit 24 outputs output signals according to the level of the detection signal from the photodiode 17 to an A/D conversion part 25 and maintains the peak level even after the level of the detection signal from the photodiode 17 reaches the peak. Then, when the level of the detection signal from the photodiode 18 rises, the sample-and-hold circuit 24 turns the level of the output signals to a low level. COPYRIGHT: (C)2003,JPO
|
