Patent ID: 8509040
Filing Date: 2013-08-13
Classification: G11B

Abstract:
1. An optical pickup device comprising: a semiconductor laser that emits a optical beam; an objective lens that irradiates the optical beam emitted from the semiconductor laser to an optical disc; a polarization diffraction grating that diffracts a first optical beam and a second optical beam from the optical beam reflected by the optical disc, a polarization state of the first optical beam being different from that of the second optical beam; an optical detector having a plurality of light receiving parts for receiving the optical beam diverged by the polarization diffraction grating; a diverging element which diverges a light path from the semiconductor laser to the optical disc and a light path from the optical disc to the optical detector; and a polarization device which transmits an optical beam having a predetermined polarization component; wherein the polarization diffraction grating and the polarization device are mounted between the diverging element and the optical detector; wherein the first optical beam and the second optical beam diffracted by the polarization diffraction grating enter the optical detector through the polarization device; and wherein the polarization device includes at least a first domain that transmits the first optical beam and fades the second optical beam and a second domain that transmits the second optical beam and fades the first optical beam.