Patent ID: 7965590
Filing Date: 2011-06-21
Classification: G11B

Abstract:
1. An optical disc apparatus for recording information on an optical disc, comprising: a laser diode that emits a laser light; a lens that focuses the laser light on the optical disc; lens adjustment means that adjusts a position of the lens; means that divides the laser light into a main beam and a sub beam; means that detects the main beam to output a main push-pull signal; means that detects the sub beam to output a sub push-pull signal; means that outputs a differential push-pull signal from the main push-pull signal and the sub push-pull signal; laser intensity detecting means that detects a laser intensity; offset amount detecting means that detects an offset amount for each of the main push-pull signal, the sub push-pull signal, and the differential push-pull signal; and adjustment means that adjusts the offset amount on the differential push-pull signal in accordance with a variation of the offset amounts on the main push-pull signal, the sub push-pull signal, and the differential push-pull signal, in relation to the laser intensity; wherein the laser diode emits the laser light having at least a first laser intensity P wherein the offset amount detecting means detects an offset amount Mof wherein the adjustment means varies an amplification degree of the sub push-pull signal in accordance with a variation of the offset amounts on the main push-pull signal and the sub push-pull signal in relation to a variation of a laser intensity derived from the first and second laser intensities P