Patent ID: 8243566

Claim:
An optical disk recording and/or reproducing apparatus that uses an optical disk as a recording medium, and has an optical pickup that records and reproduces a signal into/from the recording medium, the optical pickup comprising: a laser diode that generates laser light for performing the recording and reproducing; an objective lens for irradiating the laser light from the laser diode onto the recording medium, and condensing reflected light from the recording medium; an actuator that is mounted with the objective lens, and performs at least focus adjustment of the objective lens, tracking adjustment of the objective lens to a recording track of the recording medium, and tilt adjustment for adjusting tilt of the objective lens for facing the recording medium; a spherical aberration correction element for correcting spherical aberration of the objective lens; a detector that detects laser light condensed by the objective lens and converts the light into an electric signal; and a temperature sensor that detects internal temperature of the optical pickup, wherein the optical disk recording/reproducing apparatus comprises: a signal generation circuit that calculates the electric signal outputted from the detector to generate at least a focusing error signal and a tracking error signal; a focus-drive-signal generation module that generates a focus drive signal for focus adjustment of the actuator based on the focusing error signal generated by the signal generation circuit; a tracking-drive-signal generation module that generates a tracking drive signal for tracking adjustment of the actuator based on the tracking error signal generated by the signal generation circuit; a signal variation measurement module that measures signal variation of at least one of the focusing error signal, the tracking error signal, the focus drive signal, and the tracking drive signal; a spherical-aberration-correction drive signal generation module that determines the signal variation measured by the signal variation measurement module, and generates a spherical-aberration-correction drive signal in the case that the signal variation is larger than a predetermined value; and a spherical-aberration-correction element drive circuit that is inputted with the spherical-aberration-correction drive signal from the spherical-aberration-correction drive signal generation module to drive the spherical aberration correction element, and wherein the spherical-aberration-correction drive signal generation module measures amount of temperature rise of the objective lens with respect to the internal temperature detected by the temperature sensor based on the signal variation measured by the signal variation measurement module, and generates the spherical-aberration-correction drive signal in the case that change in temperature as the sum of the amount of temperature rise and the internal temperature is larger than a predetermined value.