Patent ID: 6243349
Filing Date: 2001-06-05
Classification: G02B,G11B

Abstract:
An optical pickup apparatus for reproducing formation recorded in optical information recording media having a plurality of substrate thicknesses, comprising:a light source for emitting light flux;a converging optical system including an objective lens having an optical axis, a first portion, a second portion, and a third portion, the third portion being farther from the optical axis than the first portion, and the second portion being provided between the first portion and the third portion; anda photo detector, wherein in case that the objective lens converges a first light flux which passes through the first portion and a third light flux which passes through the third portion on a first image forming position, the objective lens converges a second light flux which passes through the second portion on a second image forming position which is away from the first image forming position by the distance of 4 .mu.m to 27 .mu.m and is closer to the objective lens than the first image forming position.