OPTICAL HEAD,DISC RECORDING/REPRODUCING APPARATUS,AND OBJECTIVE LENS DRIVE METHOD

摘要

An optical head comprises an integrated unit (9) having a photosensitive block for converting a reflected light from a disc−shaped recording medium (13) into an electric signal and a light source, an objective lens (11), a signal generation block (102) for generating a focus error signal and a tracking error signal from the electric signal converted from the reflected light by the photosensitive block, and a control block (101) for controlling a tracking coil (18a) and a focusing coil (18b) in accordance with the focus error signal and the tracking error signal. The control block calculates the defocus amount in accordance with the shift amount of the objective lens in the radial direction by the tracking coil and applies an offset signal generated in accordance with the defocus amount to the focus error signal.