| 摘要 |
PURPOSE:To make a thickness size of a specular surface as small as possible by making the short axis direction of plural laser beam spots having an elliptical light quantity distribution coincide with the revolving shaft direction of a rotary polyhedram mirror, and making them incident. CONSTITUTION:The first semiconductor laser 1A and a collimator lens 37A are provided in a stepped hole of a horizontal part 34b of a laser beam generating unit 30, and the second semiconductor laser 1B and the second collimator lens 37B are installed in a stepped hole of a vertical part 34c. Laser beams 2A, 2B from the semiconductor lasers 1A, 1B are made incident in a parallel state on a rotary polyhedral mirror 3, but in that case, beam spots 2a, 2b having elliptical light quantity distribution are placed so that its short axis direction coincides with the revolving shaft direction of the polyhedral mirror 3. Therefore, the thickness direction size of the specular surface can be made as small as possible. |
