Patent ID: 7295498

Claim:
A disk apparatus which reproduces information by irradiating an optical beam to a disk, the disk apparatus comprising: a photodetector which comprises two or more photodetection cells, receives a reflected light from a disk, and outputs a photodetection signal based on the received reflected light; a first tracking error signal generator which detects a phase difference between the photodetection signals from the photodetector, and generates a first tracking error signal corresponding to the phase difference; a first variable amplifier which varies an amplitude of the first tracking error signal; a second tracking error signal generator which detects a level difference between the photodetection signals from the photodetector; and generates from the photodetection signal a second tracking error signal corresponding to the level difference; a second variable amplifier which varies an amplitude of the second tracking error signal; an adder which adds the first and second tracking error signals generated by the first and second variable amplifiers to provide an added tracking error signal; a muting unit which mutes the first tracking error signal when the first tracking error signal amplitude is lower than a predetermined reference, and mutes the second tracking error signal when the second tracking error signal amplitude is lower than a predetermined reference; and a tracking control unit which controls tracking by using the added error signal provided from the adder.