Patent ID: 8203917
Filing Date: 2012-06-19
Classification: G11B

Abstract:
1. An optical pickup apparatus, comprising: a laser light source; an objective lens for converging a laser light emitted from the laser light source on a recording medium; a photodetecting section for receiving the laser light reflected by the recording medium; and an optical system for guiding the laser light emitted from the laser light source to the objective lens and also for guiding the laser light reflected by the recording medium to the photodetecting section as a convergent light, wherein the photodetecting section comprises: first and second photodetectors disposed at positions at which a first part of the target laser light and a second part different from the first part are respectively received, the positions being separated further from the optical system than a convergence position of a target laser light reflected by an irradiation-target recording layer, out of the laser light reflected by the recording medium, and a third photodetector disposed at a position closer to the optical system than the convergence position of the target laser light, the position being a position where the second part of the target laser light impinges upon the third photodetector.