Patent ID: 8279730
Filing Date: 2012-10-02
Classification: G11B

Abstract:
1. An optical disc apparatus for performing both the operation of writing data on an optical disc and the operation of reading data that is stored on the optical disc, the apparatus comprising: a motor for rotating the optical disc; an optical pickup, which irradiates the optical disc with a light beam and detects the light that has been reflected from the optical disc; an evaluation section for obtaining an indicative parameter of the distortion of a signal waveform representing the light reflected from a data stored part on the optical disc while the optical disc is being rotated by the motor; a control section for changing the number of revolutions of the optical disc per unit time if a variation in the indicative parameter of the distortion per rotation of the optical disc exceeds a threshold value while the optical disc is being rotated by the motor; and a measuring section for measuring the magnitude of eccentricity of the optical disc being rotated by the motor, wherein when the magnitude of eccentricity of the optical disc measured exceeds a reference value, the evaluation section detects the indicative parameter of the distortion.