| 摘要 |
An object of the invention is to provide an optical pickup apparatus which, using a single optical system having a large NA objective lens, can compensate for the spherical aberration caused due to manufacturing errors in the thickness of recording media, as well as the spherical aberration caused due to the recording surface position in the thickness direction which differs depending on the type of recording medium, and can thus perform recording or playback on different types of recording media. A lens assembly having a plurality of lenses each of which is independently displaceable along its optical axis is interposed between a light source and an objective lens, and the lenses in the lens assembly are moved by a lens driving means independently of each other along their respective optical axes in such a manner as to reduce a spherical aberration caused due to the thickness of the light transmitting layer of the recording medium and spherical aberrations on optical surfaces of the optical system.
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