| 摘要 |
PURPOSE:To reduce the size and weight of the light pickup of an optical disk device. CONSTITUTION:A trapezoid prism 1 is used which consists of a first face 2 vertical to an optical disk panel and whose inner surface is a reflection surface, a second face 4 forming an angle of approximately 45 degrees and reflecting a laser beam incident from the first face 2 to the optical disk panel, a reflection type hologram 12 vertical to the first face 2, forming an angle of 45 degrees and using the optical axis of a semiconductor laser 9 as its center and a transmission type grating objective lens 17 around the reflection hologram 12. Thus, an optical path length can be secured by the reciprocal reflection of the laser beam, and an extremely small light pickup can be constructed by integrating the semiconductor laser 9 with a multi-partitite photosensor 27. |
