Patent ID: 7164638
Filing Date: 2007-01-16
Classification: G11B

Abstract:
1. An optical head for recording a signal in an optical recording medium or reproducing a signal recorded in the optical recording medium, the optical head comprising: a light source; an objective lens for focusing light emitted from the light source on the optical recording medium; a tilt-related-aberration correcting means for correcting an aberration that occurs when the optical recording medium tilts; and a driving amount determining means for determining a driving amount necessary for the tilt-related-aberration correcting means, wherein the tilt-related-aberration correcting means is a means for tilting the objective lens which is provided with the driving amount determined by the driving amount determining means according to information concerning a tilt of the optical recording medium and information concerning a substrate thickness of the optical recording medium; the objective lens has a certain set numerical aperture (NA), and a tilted amount of the objective lens is varied according to the substrate thickness of the optical recording medium.