Optical head, disc recording/reproducing apparatus, and objective lens drive method

摘要

An optical head includes an integrated unit (9) having a light-receiving portion for converting reflected light from a disc-shape recording medium (13) into an electric signal and a light source, an objective lens (11), a tracking coil (18a) for driving the objective lens (11) in a radial direction of the disc-shape recording medium (13), a focusing coil (18b) for driving the objective lens (11) in a focus direction of the disc-shape recording medium (13), a signal generation portion (102) for generating a focus error signal and a tracking error signal from the electric signal converted at the light-receiving portion, and a control portion (101) for controlling the tracking coil (18a) and the focusing coil (18b) on the basis of the focus error signal and the tracking error signal. The control portion calculates a defocus amount corresponding to a shift amount of the objective lens in the radial direction due to the tracking coil and applies an offset signal generated on the basis of the defocus amount to the focus error signal.