| 摘要 |
PURPOSE:To obtain the stable laser beam output and to prolong the laser life by using a gas laser as the laser beam generating means and minimizing the laser beam quantity except the reading period. CONSTITUTION:A laser beam 17, which is a film reading beam emitted from a gas laser device 11 by a laser control device 10 that makes a laser beam output into the desired value at a series of the reading period only and keeps to a small output except a series of the reading period, transmits the wavelength area of the laser beam only to a filter 12. By deflecting the laser beam 17, the light is made incident on a galvanometer mirror 18 through an acoustooptic element 13 to emit and quench equally the laser beam 17 for a film 20 and a pin hole of a shielding plate 14. When the acoustooptic element 13 is operated, the laser beam 17 is branched along light paths 201-204, the pin hole 23 is provided to the shielding plate 14, the the laser beam is equally emitted and quenched.
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