EP0332408A1
Expired / Lapsed
EP
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Magneto-optical recording device
Assignee: Hitachi Ltd
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Filing: 1989-03-07
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Granted: —
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Expires: 2009-03-07
Abstract
Abstract A magneto-optical recording device is provided which is capable of erasing, recording and/or reproducing information on the same track of a magneto-optical disc recording medium apparently at the same time. Three separate laser sources (2, 10, 12) are provided for emitting an erasing light beam, a recording light beam and a reproduction light beam to the recording medium, with each of the laser sources being adapted to irradiate the same track on recording medium with a light spot in such a manner that the light spots from the three laser sources are arranged in this order from the upstream side of the advancing track. Constant magnetic bias fields in opposite directions are generated at locations where the light beams from the first, erasing, and second, recording, light beam laser sources are irradiated.
Inventors
- 👤 Yoshito 1816-4 Shimoinayoshi Tanaka
- 👤 Hideo 2-24-9 Keyakidai Fujiwara
- 👤 Yasunori Kanazawa
- 👤 Takeshi Haitsu Asahi 102 Nakao
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 19:59
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10515; G11B11/10517; G11B11/10519; G11B11/1055; G11B11/10576
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
156 words
A magneto-optical recording device comprising a first laser source (2) for emitting an erasing light beam to a magneto-optical recording medium (1); a second laser source (10) for emitting a recording light beam to said magneto-optical recording medium (1); a third laser source (12) for emitting a reproduction light beam to said magneto-optical recording medium (1); each of said laser sources (2, 10, 12) being adapted to irradiate a same track (1A) on said magneto-optical recording medium (1) with a light spot (S1, S2, S3) in such a manner that said light spots (S1, S2, S3) from said first, second and third laser sources (2, 10, 12) are arranged in this order from an upstream side of the advancing track (1A); and a magnetic field generation means (29) for generating constant magnetic bias fields in opposite directions at locations (1N, 1R) where said light beams from said first and second laser sources (2, 10) are irradiated.
Claim 2
Dependent Claim
156 words
A magneto-optical recording device comprising a first laser source (2) for emitting an erasing light beam to a magneto-optical recording medium (1); a second laser source (10) for emitting a recording light beam to said magneto-optical recording medium (1); a third laser source (12) for emitting a reproduction light beam to said magneto-optical recording medium (1); each of said laser sources (2, 10, 12) being adapted to irradiate a same track (1A) on said magneto-optical recording medium (1) with a light spot (S1, S2, S3) in such a manner that said light spots (S1, S2, S3) from said first, second and third laser sources (2, 10, 12) are arranged in this order from an upstream side of the advancing track (1A); and a magnetic field generation means (29) for generating constant magnetic bias fields in opposite directions at locations (1N, 1R) where said light beams from said first and second laser sources (2, 10) are irradiated.
Claim 3
Dependent Claim
78 words
A magneto-optical recording device according to Claim 1, wherein a laser diode chip for said second laser source (10) and a laser diode chip for said third laser source (12) are received in the same package, and said light beams emitted from said second and third laser sources (10, 12) are led onto said magneto-optical recording medium (1) through a same optical system (16, 17, 18) to form said light spots (S2, S3) at a given distance therebetween.
Claim 4
Dependent Claim
106 words
A magneto-optical recording device according to Claim 1, wherein said magnetic field generation means (29) comprises a permanent magnet and is placed at a side of said recording medium (1) opposite to a side to which said light spots (S1, S2, S3) are irradiated from said laser sources (2, 10, 12) with said magneto-optical recording medium (1) interposed therebetween, the permanent magnet (29) as being mounted on a same carriage (30) as detection means (8, 21) for detecting the light beams of said light spots (S1, S2, S3) reflected from said recording medium (1) so as to be moved in a direction crossing said track (1A)
Claim 5
Dependent Claim
40 words
A magneto-optical recording device according to Claim 3, wherein said magnetic field generation means (29) is stationarily held by said carriage (30) at a position 0.5 mm or more apart from a reference surface of said magneto-optical recording medium (1).
Claim 6
Dependent Claim
45 words
A magneto-optical recording device according to Claim 3, wherein said magnetic field generation means (29) is so controlled as to be kept placed at a given distance from the surface of said magneto-optical recording medium (1) by an actuator (38) provided on said carriage (30).
References Cited (Backward Citations)
EP0126596A2
Cited
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