Patent ID: 8068393

Claim:
An optical disc apparatus which detects information recorded in a rotating optical disc by using a laser beam and reproduces data, comprising: an emitting unit configured to emit a laser beam to the rotating optical disc; a divided photodetector including a first divided portion and a second divided portion disposed in a light path of the reflected beam or transmitted beam from the optical record disc, wherein the first divided portion outputs a first photodetector signal, and the second divided portion outputs a second photodetector signal; a phase difference detector configured to produce a phase difference signal from a phase difference between the first photodetector signal and the second photodetector signal detected by the phase difference detector; an integrator configured to produce an integral signal from an integration of the phase difference signal; a tracking controller configured to perform tracking control of the emitting unit based on the integral signal outputted from the integrator; an amplitude detector configured to detect an amplitude of a DPD detection signal obtained from the optical disc; a setting unit configured to set an amplitude for limiting based on a window amount depending on information corresponding to a reproduction speed of the optical disc and a reference value of the window amount for digitalizing generated using the amplitude detected by the amplitude detector; and a limiter configured to limit the DPD detection signal to be supplied from the divided photodetector to the phase difference detector or the integral signal to be supplied from the phase difference detector to the integrator, when the amplitude detected by the amplitude detector is not more than the amplitude for limiting set by the setting unit.