Patent ID: 7379398

Claim:
An optical disc apparatus, comprising: a focus position changing section operable to change a focus position of a light beam with which an optical disc is irradiated; a spherical aberration amount changing section operable to change a spherical aberration amount which is generated in a spot of the light beam formed on an information surface of the optical disc; a tracking error detecting section for detecting a tracking error indicating a positional shift between the spot of the light beam and a track on the information surface of the optical disc and generating a tracking error signal indicating the tracking error; a tracking control section for performing a tracking control in accordance with the tracking error signal; a reproduced signal quality index generating section for generating a reproduced signal quality index indicating a quality of a reproduced signal from the information surface of the optical disc; and a control section for controlling the focus position changing section, the spherical aberration amount changing section and the tracking control section; wherein the control section is operable to switch an on/off state of the tracking control, the control section performs a first search while the tracking control is in the off state, the first search for searching for a plurality of sets of the focus positions of the light beam and the spherical aberration amounts such that an amplitude of the tracking error signal is greater than a predetermined value by controlling the focus position changing section to change the focus position of the light beam and controlling the spherical aberration amount changing section to change the spherical aberration amount, and the control section performs a second search while the tracking control is in the on state, the second search for determining a set of the focus position of the light beam and the spherical aberration amount such that the reproduced signal quality index is substantially optimal, among the plurality of sets of the focus positions of the light beam and the spherical aberration amounts obtained in the first search.