| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect a reference position of a lens moved in the optical axis direction in a relay lens system. <P>SOLUTION: In the optical pickup apparatus 10A in which a relay lens system 17 correcting spherical aberration caused by a thickness error of a transparent cover layer Db formed between a laser beam incident plane Da and a signal plane Dc of an optical disk D is provided between a laser light source 11 and an objective lens 19, a shielding plate 37 moved in the optical axis direction integrally with the lens 17A is provided in a relay lens drive mechanism part 30 which controls movement of at least one lens 17A in this lens system 17 in the optical axis direction so that spherical aberration is reduced based on an output of a spherical aberration detecting means 40A, and the apparatus is provided with a photodetecting means detecting a reference position being movement reference of the lens 17A when at least a part of the laser light L is shielded by the shielding plate 37, the photodetecting means shares a photodetector 16 for front monitor previously provided between the laser light source 11 and the objective lens 19. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
