Optical disc tilt control apparatus

摘要

An optical disc apparatus corrects the tilting of the optical disc with a high accuracy using first and second tracking error signals. A first tracking error signal, which is an output of subtractor (125), obtained by the push-pull method is corrected by detecting a second tracking error signal. The second tracking error signal is obtained by using the difference of amplitude of first and second signals, which are outputs of adder (130). The first signal is obtained when the light beam passes over a first pit sequence formed in a position offset in one direction orthogonal to the track of disc (100). The second signal is obtained when the light beam passes over a second pit sequence formed in a position offset in the other direction orthogonal to the track.