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1. (WO1997015923) OPTICAL HEAD
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1997/015923 International Application No.: PCT/JP1996/003141
Publication Date: 01.05.1997 International Filing Date: 28.10.1996
Chapter 2 Demand Filed: 07.05.1997
IPC:
G11B 7/09 (2006.01) ,G11B 7/095 (2006.01) ,G11B 7/13 (2012.01) ,G11B 7/135 (2012.01)
G PHYSICS
11
INFORMATION STORAGE
B
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7
Recording 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
08
Disposition or mounting of heads or light sources relatively to record carriers
09
with 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
G PHYSICS
11
INFORMATION STORAGE
B
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7
Recording 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
08
Disposition or mounting of heads or light sources relatively to record carriers
09
with 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
095
specially adapted for discs, e.g. for compensation of eccentricity or wobble
G PHYSICS
11
INFORMATION STORAGE
B
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7
Recording 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
12
Heads, e.g. forming of the optical beam spot or modulation of the optical beam
13
Optical detectors therefor
G PHYSICS
11
INFORMATION STORAGE
B
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
7
Recording 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
12
Heads, e.g. forming of the optical beam spot or modulation of the optical beam
135
Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
Applicants:
MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. [JP/JP]; 1006, Oaza Kadoma Kadoma-shi Osaka 571, JP (AllExceptUS)
NAGATA, Takayuki [JP/JP]; JP (UsOnly)
ARAI, Akihiro [JP/JP]; JP (UsOnly)
NAKAMURA, Toru [JP/JP]; JP (UsOnly)
HAYASHI, Takao [JP/JP]; JP (UsOnly)
Inventors:
NAGATA, Takayuki; JP
ARAI, Akihiro; JP
NAKAMURA, Toru; JP
HAYASHI, Takao; JP
Agent:
AOYAMA, Tamotsu ; Aoyama & Partners IMP Building 3-7, Shiromi 1-chome Chuo-ku, Osaka-shi Osaka 540, JP
Priority Data:
7/28037227.10.1995JP
Title (EN) OPTICAL HEAD
(FR) TETE OPTIQUE
Abstract:
(EN) An optical head comprises a photodetector (8) having divided photosensitive areas to detect light (13) reflected from an optical disk (7), means (10, 11, 12) for obtaining tracking error signal by operating signals from the photosensitive areas. The photodetector (8) has a first division line (9a) parallel to an information track on the optical disk and second and third division lines (9b, 9c) perpendicular to the first division line (9a) and symmetrical to the optical axis. Further, a light-shielding area (8i) for shielding a part of the reflected light between the division lines (9b and 9c). The signals are operated to reduce offset of the tracking error signal due to shift of object lens and tilt of the optical disk. Then, the optical head has small offset of tracking error signal with a simple structure as prior art optical head of push-pull technique.
(FR) La présente invention concerne une tête optique constituée d'un photodétecteur (8) comportant des zones de division photosensibles permettant de détecter la lumière (13) réfléchie par un disque optique (7), et des organes (10, 11, 12) produisant un signal d'erreur de poursuite de piste par exploitation de signaux provenant des zones photosensibles. Le photodétecteur (8) présente une première ligne de division (9a) parallèle à une piste d'informations du disque optique, et une deuxième et troisième ligne (9b et 9c), perpendiculaires à la première ligne de division (9a), et symétriques à l'axe optique. En outre, une zone faisant écran à la lumière (8i) arrête une partie de la lumière réfléchie entre les lignes de division (9b et 9c). Les signaux sont mis en ÷uvre de façon à réduire le décalage affectant le signal d'erreur de poursuite de piste par suite d'une translation de l'objectif ou d'une inclinaison du disque optique. Cette conception permet de réaliser une tête optique caractérisée par un faible décalage du signal d'erreur de poursuite de piste et par une structure simple en comparaison aux têtes optiques utilisant, selon l'état antérieur de la technique, un système à va-et-vient.
Designated States: CN, JP, KR, SG, US
European Patent Office (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE)
Publication Language: English (EN)
Filing Language: English (EN)
Also published as:
SG53183EP0882292US20010055248US6275463JPH11513835 CN1204414
KR1019990067081