Patent ID: 7855941

Claim:
An optical disk device for performing recording or playback of information by irradiating a laser beam on an optical disk, the optical disk device comprising: an optical detector module that outputs an electric signal corresponding to an amount of reflected light from the optical disk; a servo error signal generating module that generates a servo error signal from an output signal of the optical detector module; a control module that executes feedback control by generating a driving signal that drives a servo actuator in accordance with the servo error signal; a disk rotating module that rotates the optical disk; a rotation synchronous signal generating module that generates a signal synchronous with the rotation from an output of the disk rotating module; a rotation period information acquiring module that acquires rotation period information of the optical disk; a summing module that sums a compensation signal to a predetermined signal in a servo loop, the compensation signal being used to compensate for a periodical disturbance input into a servo system of the optical disk device in units of a rotation angle of the disk rotating module; a storing module that stores an output signal of the summing module in a zero-order hold manner, synchronously with the output signal of the rotation synchronous signal generating module; and a phase lead imparting module that imparts a predetermined amount of phase lead to the output signal of the storing module and that outputs the predetermined amount of phase lead as the compensation signal, wherein the predetermined amount of phase lead is determined in accordance with the rotation period information.