FOCUS CONTROLLING DEVICE AND METHOD, AND FOCUS CONTROL PROGRAM

摘要

A focus controlling device comprises an optical pickup (4) for converting reflected light of a laser beam applied to a disk into an electrical signal. The optical pickup (4) has an objective lens (42) for applying the laser beam and receiving the reflected light and a two-axis actuator (43) for driving the objective lens (42). The focus controlling device further comprises a focus error signal detecting section (52) for detecting an actuator drive signal according to the electrical signal from the optical pickup (4), an actuator drive section (56) for controlling the driving of the two-axis actuator (43) according to the actuator drive signal so that the objective lens (42) is focused, a focus gain setting section for setting the focus gain of the actuator drive signal, and a focus gain control section (54) for clipping the drive signal waveform.