Patent ID: 8634281

Claim:
An optical disc device employing an optical pickup which reproduces or records information by reading or writing data from/to a disc having a data layer and a servo layer, the optical disc device comprising: an objective lens which moves in a radial direction of the disc and thereby moves focusing positions of first and second beam spots in the radial direction of the disc; a tracking actuator which drives the objective lens in the radial direction of the disc; a first detector which converts reflected light of the first beam spot from the data layer into an electric signal; a second detector which converts reflected light of the second beam spot from the servo layer into an electric signal; a first tracking error signal generating unit which generates a first tracking error signal based on the output of the first detector; a second tracking error signal generating unit which generates a second tracking error signal based on the output of the second detector; a tracking control unit which generates a control signal for positioning the first beam spot or the second beam spot at a prescribed track based on the output of the first tracking error signal generating unit or the second tracking error signal generating unit; a tracking actuator driving unit which drives the tracking actuator based on the output of the tracking control unit; and a tracking error level detecting unit which detects a tracking error level based on the output of the first tracking error signal generating unit or the second tracking error signal generating unit, wherein: the tracking control unit drives the tracking actuator based on the output of the first detector in normal data reproduction, and the tracking control unit detects that the output of the first tracking error signal generating unit has exceeded a prescribed range based on the output of the tracking error level detecting unit and then operates to drive the tracking actuator based on the output of the second detector, and the tracking control unit detects that the output of the second tracking error signal generating unit has come within a prescribed range based on the output of the tracking error level detecting unit and then operates to drive the tracking actuator based on the output of the first detector again.