Patent ID: 7852733
Filing Date: 2010-12-14
Classification: G11B

Abstract:
1. An optical pickup apparatus for shining light on an optical disk having two recording layers and for detecting reflected light from the optical disk, comprising: a light source configured to shine the light on the optical disk; an optical system situated on a path of a light beam returning from the optical disk inclusive of light reflected by a first recording layer of the optical disk and light reflected by a second recording layer of the optical disk, said optical system including: a light condensing optical unit to turn the returning light beam into a condensing light beam; and a light beam regulating unit to extract from the condensing light beam a partial-cross-section light beam corresponding to only a part of a cross section of the condensing light beam; and one or more photo detectors, situated between a first position where the light reflected by the first recording layer contained in the partial-cross-section light beam is condensed and a second position where the light reflected by the second recording layer contained in the partial-cross-section light beam is condensed, said one or more photo detectors having a first photo detecting section to detect the light reflected by the first recording layer and a second photo detecting section to detect the light reflected by the second recording layer, and the first and second positions being spaced apart from each other along an optical axis of the light condensing optical unit, wherein substantially no light reflected by the first recording layer reaches the second photo detecting section, and substantially no light reflected by the second recording layer reaches the first photo detecting section that is in contact with and adjoins the second photo detecting section, the light shone by the light source on the optical disk being focused selectively on one of the first recording layer and the second recording layer.