| 摘要 |
PURPOSE:To lighten the movable part of an optical head and to improve an access speed by deflecting these optical paths between an objective lens and an optical system containing a laser light source and a light receiving means and making to coincide reciprocal optical axies by a fixed deflection means. CONSTITUTION:Between a fixed optical system 7 containing the laser light source 8, a photodetector 9 and an objective lens 6 driven in the direction of seeking, a thin type prism body 10 is provided which deflects these optical paths and whose incident plane 10a is prolonged and present in the movable range of the movable part 5. The optical axis from the optical system 7 is deflected 90 degree by the prism 10, and a transparent plate is rotated in accordance with the position of the movable part 5 by a radial direction driving part 14 and the optical path of the incident/emitting light beam of the optical system 7 is moved in parallel. Then, by using the prism body 10 deflecting 90 degree even when the angle forming with the optical path is smaller than 45 degree, the volume of the optical head is reduced. Thus, the movable part of the optical part 4 is lightened and the access speed is improved, and a device is thinned and miniaturized. |
