Patent ID: 9082429
Filing Date: 2015-07-14
Classification: G11B

Abstract:
1. An optical disc device compatible with multilayer optical discs having a plurality of recording layers on one side, comprising: an optical pickup for applying light to an optical disc to detect return light from the optical disc by a photodetector; a focus-error-signal generation section for generating a focus error signal of a differential astigmatic method by using a parameter and an electric signal outputted from the photodetector; a control section for controlling the optical pickup to make a focus jump operation such that a focus position of the light is moved from a first recording layer to a second recording layer of the optical disc; and a parameter value changing section for temporarily changing a value of the parameter to be used to generate the focus error signal of the differential astigmatic method by the focus-error-signal generation section while the focus jump operation is performed by using the focus error signal of the differential astigmatic method, wherein the parameter value changing section temporarily changes a value of a multiplication coefficient by which a sub-beam component of the return light detected by the photodetector is multiplied.