| 摘要 |
PURPOSE:To record and reproduce stably an information signal by detecting a clock signal which is used to read other information signal, e.g. recording information signal accurately independently of a recording information signal recorded by using magnetooptic effect. CONSTITUTION:Light from a semiconductor laser 7 is converted by a coupling lens 8 into parallel luminous flux, which is made incident on an objective lens 10 through a beam splitter 11 to form a fine spot on a disk 6. The objective lens 10 is fitted to a voice coil 9 so that it is moved following up vertical oscillations of the disk 6. Reflected light from the disk 6 is passed through the objective lens 10 and split by the beam splitter 11, and the light is guided to an optical path different from irradiated laser luminous flux and further separated into two optical paths through a half-prism 12. One piece of luminous flux is passed through an analyzer 14 to select a specific plane thetaa2 of polarization, its passing light is photodetected by a photodetector 15; and the other piece of luminous flux is passed through an analyzer 13 to select a specific plane thetaa1 of polarization, and its passing light is photodetected by a photodetector 16. |
