| 摘要 |
PURPOSE:To obtain an optical pickup which has a large S/N and can perform the stable reproduction by projecting the direction vertical to the junction face of a semiconductor laser in the direction having a slope toward the tangent line of a disk track. CONSTITUTION:For an optical pickup of an optical disk, the direction vertical to the junction face of a semiconductor laser 1 is projected on a track in the direction where an angle theta has about 70 deg. slope in the tangent line direction of the track vertical to the radius direction B of a disk 5. For this purpose, a laser beam is made incident on a half prism 2 and a collimator lens 3. Then the parallel beams are focused on the disk 5 through an objective lens 4. The reflected beam given from the disk track is led to a photodiode 7 having a photodetecting surface through a lens 4, the lens 3 and the prism 2 and then a cylindrical lens 6. Thus a circular and equivalent focused image is formed on the photodetecting face of the diode 7. Thus a stable far field pattern FFP is obtained to ensure the excellent reproduction.
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