Patent ID: 6928034
Filing Date: 2005-08-09
Classification: G11B

Abstract:
1. An optical disc apparatus in which a laser beam from an optical pickup is shone onto a recording surface of an optical disc, and information is read from the optical disc, comprising: a servo constant changing section, which successively changes a servo constant; a jitter measurement section, which measures a jitter value of an output signal from the optical pickup; a minimum jitter measurement section, which establishes a minimum jitter value from each jitter value measured in response to a successively changed servo constant; a jitter threshold value setting section, which sets a jitter threshold value by multiplying the minimum jitter value by a prescribed ratio; a servo constant establishing section, which of jitter values measured in correspondence to a successively changed servo constant, sets at least two jitter values substantially equal to the jitter threshold value, and establishes a servo constant corresponding to the set jitter values; and an optimum servo constant setting section, which, based on the servo constant corresponding to the minimum of two jitter constants, sets an optimum servo constant.