Patent ID: 8971162
Filing Date: 2015-03-03
Classification: G11B

Abstract:
1. An optical disc device comprising: an optical pickup including an objective lens which focuses a laser light from a predetermined light source on any position on an optical disc, and a receiver unit configured to receive light reflected off the optical disc; a signal processing unit configured to generate a main push-pull signal and a sub push-pull signal from signals from the receiver unit, and subtract, from the main push-pull signal, a signal obtained by multiplying the sub push-pull signal K times, to generate a tracking-error signal; and a control unit configured to perform tracking control in response to the tracking-error signal and a lens-error signal which indicates displacement of the objective lens, wherein the control unit is configured to perform: a midpoint servo process of aligning a radial position of the objective lens with a midpoint location; an offset process of adding an offset value to the lens-error signal after a start of the midpoint servo process; a stabilization awaiting process of waiting for oscillation of the optical disc to stabilize, after performing the offset process; a measurement process of measuring the tracking-error signal using the signal processing unit, after performing the stabilization awaiting process; and a K value adjusting process of adjusting a value of the K, in response to a result of the measurement process.