Patent ID: 7542637
Filing Date: 2009-06-02
Classification: G02B,G11B

Abstract:
1. A coupling optical system for use in are optical pickup apparatus which comprises a light source, and an objective lens, and which records and/or reproduces information by converging a light flux emitted from the light source onto an information recording surface of an optical information recording medium through the objective lens, the coupling optical system being arranged between the light source and the objective lens, the coupling optical system comprising: a first optical element with a power adopted to be arranged in a non-parallel light flux between the light source and the objective lens; and a second optical element with a positive power arranged between the first optical element and the objective lens, wherein the first optical element comprises wherein when a non-parallel light flux emitted from the light source enters into the out-effective-aperture section, the light-reduction structure reduces a light flux to be emitted from the second optical element in a direction getting closer to an optical axis of the second optical element in comparison with a direction traveling parallel to the optical axis.