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1. WO1996004649 - OPTICAL PICKUP APPARATUS

Publication Number WO/1996/004649
Publication Date 15.02.1996
International Application No. PCT/JP1995/001511
International Filing Date 28.07.1995
IPC
G11B 11/105 2006.01
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
11Recording on, or reproducing from, the same record carrier wherein for these two operations the methods or means are covered by different main groups of groups G11B3/-G11B7/212; Record carriers therefor
10using recording by magnetisation or demagnetisation
105using a beam of light or a magnetic field for recording and a beam of light for reproducing, e.g. light-induced thermo-magnetic recording, Kerr effect reproducing
G11B 7/12 2012.01
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 7/135 2012.01
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 7/125 2012.01
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
125Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
CPC
G11B 11/10543
GPHYSICS
11INFORMATION STORAGE
BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
11Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
10using recording by magnetic means ; or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
105using a beam of light or a magnetic field for recording ; by change of magnetisation; and a beam of light for reproducing, ; i.e. magneto-optical,; e.g. light-induced thermo-magnetic recording, ; spin magnetisation recording,; Kerr ; or Faraday; effect reproducing
10532Heads
10541for reproducing
10543using optical beam of radiation
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 7/126
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
125Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
126Circuits, methods or arrangements for laser control or stabilisation
G11B 7/1365
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
1365Separate or integrated refractive elements, e.g. wave plates
Applicants
  • SONY CORPORATION [JP/JP]; 7-35, Kitashinagawa 6-chome Shinagawa-ku Tokyo 141, JP (AllExceptUS)
  • EGUCHI, Naoya [JP/JP]; JP (UsOnly)
  • WIECHMANN, Werner [DE/JP]; JP (UsOnly)
Inventors
  • EGUCHI, Naoya; JP
  • WIECHMANN, Werner; JP
Agents
  • KOIKE, Akira ; No. 11 Mori Building 6-4, Toranomon 2-chome Minato-ku Tokyo 105, JP
Priority Data
6/17820529.07.1994JP
6/26500928.10.1994JP
Publication Language Japanese (JA)
Filing Language Japanese (JA)
Designated States
Title
(EN) OPTICAL PICKUP APPARATUS
(FR) APPAREIL DE LECTURE OPTIQUE
Abstract
(EN)
Since an S-polarized laser beam sent out from a laser diode is ordinary ray with respect to an optical element having birefringent characteristics, it enters a quarter-wave plate with its optical path not changed. The quarter-wave plate turns this laser beam into circularly polarized light. An objective lens condenses the laser beam of circularly polarized light on a signal recording surface of a disk. The return light reflected on the signal recording surface of the disk enters the quarter-wave plate again through the objective lens. The quarter-wave plate turns this incident return light into P-polarized light. A laser beam of this P-polarized light becomes abnormal light with respect to an optical element (2) having birefringent characteristics. The optical element having birefringent characteristics changes the optical path of the P-polarized laser beam, the abnormal light. Accordingly, the return light from the disk does not return to the laser diode but to a light condensing surface of a photodetector.
(FR)
Etant donné qu'un rayon laser à polarisation S envoyé par une diode laser est un rayon ordinaire par rapport à un élément optique à caractéristiques biréfringentes, il pénètre dans une plaque quart d'onde sans que son trajet optique soit modifié. Ladite plaque quart d'onde transforme ce rayon laser en en lumière polarisée de manière circulaire. Un objectif condense le rayon laser de lumière polarisée de manière circulaire sur la surface d'enregistrement de signaux d'un disque. La lumière réfléchie par la surface d'enregistrement de signaux du disque pénètre dans la plaque quart d'onde une nouvelle fois par l'objectif. La plaque quart d'onde transforme cette lumière renvoyée incidente en lumière à polarisation P. Un rayon laser constitué de cette lumière à polarisation P devient de la lumière anormale par rapport à un élément optique (2) à caractéristiques biréfringentes. L'élément optique à caractéristiques biréfringentes modifie le trajet optique du rayon laser à polarisation P, qui est la lumière anormale. De ce fait, la lumière renvoyée par le disque ne retourne pas dans la diode laser, mais va vers la surface de condensation de la lumière d'un photodétecteur.
Also published as
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