Patent ID: 7755987

Claim:
An optical disk replay device, comprising: an optical pickup which irradiates laser light upon a track of an optical disk and receives light reflected therefrom; a tracking actuator for shifting an objective lens of the optical pickup in a tracking direction; a tracking error signal detection circuit which outputs, a push-pull tracking error signal based upon the reflected light received by the optical pickup; a phase compensation circuit which generates a tracking drive signal corresponding to the push-pull tracking error signal and outputs the tracking drive signal to the tracking actuator; and a system controller which measures a balance amount of change of the push-pull tracking error signal relative to a voltage value of the tracking drive signal, measures a balance compensation amount of the push-pull tracking error signal relative to a balance compensation value, and obtains, on a condition that the balance amount is equal to the balance compensation amount, a slope β which represents a ratio between balance compensation value and the voltage value of the tracking drive signal, wherein the system controller comprises: a balance compensation value calculation circuit which calculates, by using the slope β, a balance compensation value for the push-pull tracking error signal relative to the tracking drive signal outputted by the phase compensation circuit; a balance compensation circuit which compensates, by using the balance compensation value calculated by the balance compensation value calculation circuit, the push-pull tracking error signal detected by the tracking error signal detection circuit, and inputs this compensated push-pull tracking error signal to the phase compensation circuit; and the phase compensation circuit which generates the tracking drive signal based up on the push-pull tracking error signal compensated by the balance compensation circuit.