Optical disc apparatus

An optical disc apparatus comprising:

• an optical pickup for irradiating a laser beam onto an optical disc, and receiving the laser beam reflected from the optical disc so as to read a signal recorded on the optical disc;
• a tilt angle varying unit for varying a tilt angle of the optical pickup relative to the optical disc either from inward to outward of the optical disc or from outward to inward of the optical disc;
• an amplitude storage unit for storing amplitude values of the signal of the reflected laser beam when the tilt angle varying unit varies the tilt angle of the optical pickup;
• and
• an optimum tilt angle calculation unit for calculating a tilt angle to give a maximum value of the amplitude of the signal of the reflected laser beam,
• wherein the optimum tilt angle calculation unit calculates the tilt angle by approximating, with a cubic curve, amplitude values of the signal of the reflected laser beam corresponding to tilt angles of the optical pickup at predetermined angular intervals, the amplitude values being stored in the amplitude storage unit.