Patent ID: 7907481
Filing Date: 2011-03-15
Classification: G11B

Abstract:
1. An optical disc drive device comprising: an FE signal generator which generates a focus error signal; a TE signal generator which generates a tracking error signal; a return beam detector which detects a return beam reflected by an optical disc after irradiated by an optical pickup to generate a return beam level signal; a return beam gain setting part which sets amplitude adjustment amount of the return beam level signal so that a signal level of the return beam level signal generated by the return beam detector coincides with a predetermined reference level; an FE gain setting part which sets amplitude adjustment amount of the focus error signal in accordance with the signal level of the return beam level signal adjusted by the return beam gain setting part so that a signal amplitude of the focus error signal is constant; and a TE gain setting part which sets amplitude adjustment amount of the tracking error signal in accordance with the signal level of the return beam level signal adjusted by the return beam gain setting part so that a signal amplitude of the tracking error signal is constant; wherein the return beam gain setting part includes: a first amplitude adjustment part which adjusts an amplitude of a difference between the signal level of the return beam level signal and the reference level by a first amplitude adjustment coefficient corresponding to the return beam level signal; and a first cumulative adder which calculates a cumulative adding value of the difference adjusted by the first amplitude adjustment coefficient, the FE gain setting part includes: a second amplitude adjustment part which adjusts the amplitude of the difference by a second amplitude adjustment coefficient corresponding to the focus error signal; and a second cumulative adder which calculates a cumulative adding value of the difference adjusted by the second amplitude adjustment coefficient, the TE gain setting part includes: a third amplitude adjustment part which adjusts the amplitude of the difference by a third amplitude adjustment coefficient corresponding to the tracking error signal; and a third cumulative adder which calculates a cumulative adding value of the difference adjusted by the third amplitude adjustment coefficient.