| 摘要 |
PURPOSE:To facilitate the angle adjustment of the diffraction grating of an optical head incorporated in an optical information recording and reproducing device by turning the diffraction grating holder of the optical head due to the rotation of an eccentric pin and adjusting the inclination of the diffraction grating. CONSTITUTION:Laser light emitted from a semiconductor laser 1 is diffracted by the diffraction grating 2, and 0th order light and + or - 1st order light form an optical spot on a disk through a half prism 3 and objective lens 4. The reflected light goes reversely, is reflected by the prism 3 and is made incident on a photodetector 6 through a lens 5. For adjusting the diffraction grating, a driver, etc., are fitted in the driver groove 8e of the eccentric pin 8, and said pin 8 is rotated. Then its shaft part 8b of the pin 8 inserted into the pin receiving hole 8c of a diffraction grating holder 7 rotates to turn the diffraction holder 7 in the direction of an arrow A, whereby the inclination of the diffraction grating 2 can be adjusted.
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