| 摘要 |
PROBLEM TO BE SOLVED: To form a high-resolution and clear image by arranging lenses by deviating the center of the curvature of the curved surface of the lens which is nearest the scanning surface of a laser beam from an incident optical axis. SOLUTION: A cylindrical lens for correction 8b is arranged at a similar position to a conventional cylindrical lens for correction in plan view as shown in figure (a). However, when it is viewed from the cross section of the lens as shown in figure (b), the lens 8b is arranged, so that the center of the radius of the curvature of the curved surface 81b thereof is positioned at a point Qb, deviated from the incident optical axis of the laser beam 2. When the beam 2 is made incident on the lens 8b, a primary reflected beam 2b is emitted in a direction which is different from a beam 2a transmitted without being reflected and the image thereof is formed at the image-forming position 15 of an image-forming surface 10. As a result, the image-forming position 14 of the beam 2a transmitted without being reflected, and the image forming position 15 of the beam 2b are distant. Thus, the beam 2b does not turn into noise light.
|
