OPTICAL DISK SYSTEM AND SPHERICAL ABERRATION CORRECTION CONTROL UNIT

摘要

PROBLEM TO BE SOLVED: To overcome deterioration of recording and reproduction performance of an optical disk due to spherical aberration, which appears due to tilt of an objective lens for canceling coma aberration appearing in an optical beam spot with a warp of the disk.

SOLUTION: The optical disk system has a lens tilt section which tilts an objective lens such that the coma aberration appearing in an optical beam spot focused on a data surface is corrected; a spherical aberration correction section for correcting the spherical aberration appearing in the optical beam spot focused on the data surface; and a control section of correction of lens tilt spherical-aberration for controlling the spherical aberration correction section such that a correction level of the spherical aberration corrected by the spherical aberration correction section depending on tilt of the objective lens tilted by the lens tilt section.

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