| 摘要 |
PURPOSE:To provide an optical disk reader in which a hologram element is controlled easily. CONSTITUTION:When a luminous flux from a disk 7 is reflected by a hologram element 3, a plurality of divided fluxes are formed and respective divided fluxes reflected by the effective reflecting region 3A of the hologram element 3 are guided to a plurality of light-receiving regions (a)-(d) of a photoelectric conversion element 9. The luminous flux reflected by a non-effective reflecting region 3B is guided to a special light-receiving region (e). When the hologram element 3 is moved so that the output from the light-receiving region (e) is minimized by the use of a monitor 11, the deviation of an effective flux from the effective reflecting region can be controlled to the minimum and the control for directing of the effective flux from the disk 7 to the effective reflecting region 3A of the hologram element 3 is made easy. |
