OPTICAL GUIDE TYPE OPTICAL PICKUP

摘要

PURPOSE:To detect the change in the distance of a disk as the change in the light collecting spot at the light receiving face by transmitting the light beam of light collection and divergence of the reflected return light from a disk through a transparent base used in common for the optical guide path and the diffraction grating in common obliquely. CONSTITUTION:The light emitted from the semiconductor laser 4 is coupled with the optical guide path 2 and propagated. The propagated light is radiated as a divergent beam in a direction deviated from the perpendicular direction of the base into space from the grating coupler 3 and collected onto the surface of an optical disk 6 by the focusing lens 5. The light reflected in the surface is changed for the intensity in response to the information recorded on the disk and reaches the base 1 through reverse path and a part is coupled to the path 2 by the grating 3. Then the light is transmitted through the transparent base 1 and the transmitted light is formed directly near the center of the photodetector 7 divided into four.