Patent ID: 8089838

Claim:
An optical disc apparatus, comprising: a rotation section to rotate an optical disc including a track that is a spiral track or a concentric track formed with a predetermined track center as a center, the center being a rotational center of the optical disc; a light source to emit a light beam; an objective lens to collect the light beam on the optical disc; a lens drive section to drive the objective lens in a tracking direction that traverses the track; a light-receiving section to receive a reflected light beam that is reflected by the track formed on the optical disc and generate a light-receiving signal; a tracking error signal generation section to generate a first tracking error signal that represents a distance between the track and a focus of the light beam in the tracking direction based on the light-receiving signal; an eccentric-state acquisition section to acquire an eccentric state of the center with respect to the rotational center of the optical disc; a correction section to generate a corrected tracking error signal that represents a distance with respect to the track with the rotational center of the optical disc as the center by correcting the first tracking error signal based on the eccentric state; and a drive control section to drive the objective lens in the tracking direction by the lens drive section based at least in part on the corrected tracking error signal, wherein the optical disc has a reference direction that is defined with respect to a rotational angle with the rotational center as the center, wherein the eccentric-state acquisition section acquires an eccentric distance that is a distance from the rotational center of the optical disc to the center and an eccentric angle that is an angle formed by the center and the reference direction with the rotational center of the optical disc as the center, wherein the tracking error signal generation section determines an irradiation spot angle that is an angle formed by an irradiation spot of the light beam and the reference direction with the rotational center of the optical disc as the center based on the light-receiving signal, and wherein the correction section generates the corrected tracking error signal by correcting the first tracking error signal by using the irradiation spot angle, the eccentric angle, and the eccentric distance.