Patent ID: 8477576
Filing Date: 2013-07-02
Classification: G11B

Abstract:
1. An optical disc apparatus for recording or reproducing information by irradiating a laser beam on an optical disc, comprising: an optical disc rotating portion configured to rotate said optical disc centering around a predetermined rotation axis; a light emission power changing portion configured to change a light emission power of said laser beam; an objective lens configured to focus the light spot of said laser beam on said optical disc; an actuator configured to drive said objective lens; a photo detector portion configured to output an electric signal depending on an amount of reflection light from said optical disc; a focus error signal producing portion configured to produce a focus error signal from the output signal of said photo detector portion; a tracking error signal producing portion configured to produce a tracking error signal from the output of said photo detector portion; a focus controlling portion configured to conduct focus control upon the basis of said focus error signal; a tracking controlling portion configured to conduct tracking control upon the basis of said tracking error signal; a lens shifting detecting portion configured to detect lens shifting of said objective lens; and a minimum recording unit boundary detecting portion configured to detect a boundary of a minimum recording unit of said optical disc, wherein the light emission power of said laser beam is lowered from a recording power down to a reproducing power, in synchronism with the boundary of said minimum recording unit, thereby to stop recording of the information, in response to said lens shifting detecting portion detecting that lens shifting of said objective lens is larger than a predetermined amount during recording of the information on said optical disc.