US Patent 7800989 Disc-driving apparatus and method for controlling the same

A disc-driving apparatus has an optical pickup including an objective lens. The objective lens has an optical axis that is met on a line excluding a central axis of revolution of a disc. The apparatus has storage device that stores plural correction values obtained by detecting fluctuations in amplitude of a tracking error signal with respect to a radial direction of the disc or a quantity of de-tracking with respect to the radial direction thereof. The apparatus has control device that reads the correction value from the storage device and, when the optical pickup is operating, corrects the tracking error signal to conduct servo control based on the corrected tracking error signal.