| 摘要 |
PURPOSE:To obtain a separable optical head which does not cause offset in track deviation detecting signals or out-of-focus detecting signals. CONSTITUTION:A diffraction grating 25, beam splitter 26 and mirror prism 29 are arranged in a movable optical system 6, and a sub-beam for the detection of the track deviation (or for the focus detection) is separated in the movable optical system 6. Also, the direction of a reflection beam 30 emitted from the movable optical system 6 is made parallel to an emitted beam 24 from a fixed optical system 5, and a detecting optical system is arranged in the fixed optical system 5. Consequently by the access movement of the movable optical system, no offset is caused in the track deviation detecting signals or the focus deviation detecting signals, and the movable optical system is made light weight. |
