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US 8,509,040 B2Granted
Optical pickup device and optical disc apparatus
AssigneeHitachi Media Electronics Co., Ltd.
InventorKazuyoshi Yamazaki
Life of this patent
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Abstract
An optical pickup device includes a polarization diffraction grating to diverge an optical beam reflected from an optical disc and an optical detector to receive the optical beam diverged by the polarization diffraction grating, a polarization of 0 order diffracted light diffracted through the polarization diffraction grating is substantially perpendicular to that of a +1 order diffracted light diffracted therethrough, and a polarization filter having a plurality of domains is mounted between the polarization diffraction grating and the optical detector.
Claims18
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.
8 more elements
An optical disc apparatus comprising:
- an optical pickup device that comprises
- a semiconductor laser to emit an optical beam,
- an objective lens to irradiate the optical beam emitted from the semiconductor laser,
- a polarization diffraction grating to diffract a first optical beam and a second optical beam from the optical beam reflected by an 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 to receive 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;
- a laser actuation circuit that drives the semiconductor laser in the optical pickup device;
- a servo signal generation circuit that generates a focusing error signal and a tracking error signal by using a signal detected from the optical detector in the optical pickup device;
- and
- an information signal reproducing circuit that reproduces information signal recorded in an optical disc.
11 more elements
An optical pickup device comprising:
- a semiconductor laser that emits an 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;
- 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 fades the first optical beam and transmits the second optical beam and a second domain that fades the second optical beam and transmits the first optical beam.
7 more elements
Dependencies are inferred from the claim text.