| 摘要 |
PURPOSE:To form plural erasing spots highly accurate in shaping and positioning by one light source by providing an optical path polarizer produced by bonding two transparent conductors different in refraction factor in the optical path of a laser beam made incident to the surface of a recording material. CONSTITUTION:The light from a semiconductor laser 4 goes to a parallel beam by a collimator lens 5 and made incident to an optical path polarizer 9. This polarizer 9 consists of the incidence side transparent conductor 10 and the out-going side transparent conductor 11,and the juncture part is formed with a plane (e) and that (g) which are angled to each other in an angle theta2. A light beam that passed the juncture plane (e) and an objective lens 7 is condensed on a recording material 8 intensity distribution (c). On the other hand, a light beam after passing through the plane (g) bent to the plane (e) by the angle theta2 transmits through the lens 7 whose optical path is bent, and the beam is condensed on the recording material 8 in the intensity disribution (d). The less the difference between the refraction factors of the incidence side conductor 10 and the out-going side conductor 11 are, the more accurately the distance between erasing spots (c) and (d) are obtained. |
