Optical pickup device

Abstract

The optical pickup device according to the present invention includes: a light source which emits a first light at a first wavelength, a second light at a second wavelength and a third light at a third wavelength; an optical path combining unit which combines vectors of the first, second and third light emitted by the light source, and matches optical axes of the first light and the third light; a light collection unit which condenses the light from the optical path combining unit into the optical information storage medium; a diffraction element which diffracts reflected light from the optical information storage medium; a first photo detector, a second photo detector and a third photo detector which receives the diffracted light from the first diffraction element; and a prevention unit formed between the first diffraction element and the first photo detector, the second photo detector and the third photo detector, and which prevents irradiation of + first-order diffracted light diffracted by the first diffraction element into the first photo detector, the second photo detector, and the third photo detector.