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1. US20040156299 - Light integration unit, optical pickup device using the unit, and optical disk device

Office
United States of America
Application Number 10478263
Application Date 05.11.2002
Publication Number 20040156299
Publication Date 12.08.2004
Grant Number 7315502
Grant Date 01.01.2008
Publication Kind B2
IPC
G11B 7/135
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation, reproducing using an optical beam at lower power; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
135Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
G11B 7/09
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation, reproducing using an optical beam at lower power; Record carriers therefor
08Disposition or mounting of heads or light sources relatively to record carriers
09with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
G11B 7/12
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation, reproducing using an optical beam at lower power; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
G11B 7/13
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation, reproducing using an optical beam at lower power; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
13Optical detectors therefor
CPC
G11B 7/1353
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
135Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
1353Diffractive elements, e.g. holograms or gratings
G11B 7/0901
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
08Disposition or mounting of heads or light sources relatively to record carriers
09with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
0901for track following only
G11B 7/094
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
08Disposition or mounting of heads or light sources relatively to record carriers
09with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
094Methods and circuits for servo offset compensation
G11B 7/123
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
123Integrated head arrangements, e.g. with source and detectors mounted on the same substrate
G11B 7/131
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation ; by modifying optical properties or the physical structure; , reproducing using an optical beam at lower power ; by sensing optical properties; Record carriers therefor
12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
13Optical detectors therefor
131Arrangement of detectors in a multiple array
Applicants Sharp Kabushiki Kaisha
Inventors Sakai Keiji
Miyake Takahiro
Ueyama Tetsuo
Miki Renzaburo
Makioka Hiroshige
Fujita Noboru
Miyazaki Osamu
Agents Manus Peter J.
Conlin David G.
Edwards Angell Palmer & Dodge LLP
Priority Data 2001345072 09.11.2001 JP
2002115922 18.04.2002 JP
2002248479 28.08.2002 JP
Title
(EN) Light integration unit, optical pickup device using the unit, and optical disk device
Abstract
(EN)

An object of the present invention is to attain stable tracking servo performance by suppressing an offset caused by a shift of an object lens or a tilt of a disk, despite the one-beam method which does not cause reduction in light quantity of the main beam. A diffraction grating is provided between a hologram and a light receiving section, and a diffraction efficiency of the diffraction grating is varied in a grating longitudinal direction. For example, if an incident light beam on the diffraction grating is shifted in the grating longitudinal direction, the quantity of received light in each light receiving section varies to cause offset. By performing tracking servo so as to cancel the change, it is possible to correct the offset, thereby attaining stable tracking servo performance.