Patent ID: 7460459
Filing Date: 2008-12-02
Classification: G11B

Abstract:
1. An optical pickup apparatus for recording and/or reproducing information for an optical disk, the optical pickup apparatus comprising: a first light source for emitting a first light flux having a first wavelength λ a second light source for emitting a second light flux having a second wavelength λ a third light source for emitting a third light flux having a third wavelength λ an objective optical element wherein the optical pickup apparatus records and/or reproduces information by converging the first light flux onto the information recording surface of the first optical disk, by converging the second light flux onto the information recording surface of the second optical disk, and by converging the third light flux onto the information recording surface of the third optical disk, wherein the objective optical element comprises an optical surface comprising a central area and a peripheral area surrounding the central area, the central area comprises a first optical path difference providing structure, and the peripheral area comprises a second optical path difference providing structure, wherein the objective optical element converges the first light flux which passes through the central area of the objective optical element onto the information recording surface of the first optical disk so that the optical pickup apparatus can record and/or reproduce information on the information recording surface of the first optical disk, the objective optical element converges the second light flux which passes through the central area of the objective optical element onto the information recording surface of the second optical disk so that the optical pickup apparatus can record and/or reproduce information on the information recording surface of the second optical disk, the objective optical element converges the third light flux which passes through the central area of the objective optical element onto the information recording surface of the third optical disk so that the optical pickup apparatus can record and/or reproduce information on the information recording surface of the third optical disk, the objective optical element converges the first light flux which passes through the peripheral area of the objective optical element onto the information recording surface of the first optical disk so that the optical pickup apparatus can record and/or reproduce information on the information recording surface of the first optical disk, and the objective optical element converges the second light flux which passes through the peripheral area of the objective optical element onto the information recording surface of the second optical disk so that the optical pickup apparatus can record and/or reproduce information on the information recording surface of the second optical disk, and wherein the first optical path difference providing structure comprises at least a first basic structure, the first basic structure is an optical path difference providing structure wherein the second optical path difference providing structure comprises a predetermined basic structure, the predetermined basic structure is an optical path difference providing structure where x is an integer excluding 0, y is an integer excluding 0, n