US4939711A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arrangement for minimizing effects of leakage magnetic fields in optomagnetic recording/reproducing apparatus
Assignee: Olympus Corp
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Filing: 1988-02-24
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Granted: 1990-07-03
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Expires: 2008-02-24
Abstract
Abstract In an optomagnetic recording/reproducing apparatus, an objective lens is actuated by a lens actuator having focusing and tracking magnetic circuits so that a light beam is focused on an optical disk and is directed to a predetermined area of the optical disk. The lens actuator is mounted on a pickup body which is driven in a radial direction of the disk by a driving magnetic circuit. The optical disk is clamped on a turntable by a magnetic clamp mechanism. First leakage magnetic fields produced from each of the focusing and tracking magnetic circuits, second leakage magnetic fields are produced from the driving magnetic circuit and the magnetic clamp mechanism, and the first and second magnetic fields are directed in mutually opposite directions relative to the optical disk.
Inventors
- 👤 Yoshiro Yoda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:59
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/1055; G11B11/10576; G11B11/10556; G11B11/10567; G11B11/10571
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
159 words
An optomagnetic recording/reproducing apparatus, comprising: a light source for generating a light beam; focusing means for focusing the light beam emitted from said light source; a recording medium having a recording surface to be irradiated with the light beam focused by said focusing means; pickup means for detecting the light beam from said recording medium; bias magnetic field generating means for applying a bias magnetic field onto said recording medium; and first magnetic field generating means for generating a first magnetic field, and second magnetic field generating means for generating a second magnetic field, the first and the second magnetic field generating means being associated with components of the recording/reproducing apparatus other than said bias magnetic field generating means, the first and the second magnetic fields being directed in directions opposite to one another onto that region of said recording medium which is irradiated with the light beam for minimizing interference with said bias magnetic field at said region.
Claim 2
Dependent Claim
159 words
An optomagnetic recording/reproducing apparatus, comprising: a light source for generating a light beam; focusing means for focusing the light beam emitted from said light source; a recording medium having a recording surface to be irradiated with the light beam focused by said focusing means; pickup means for detecting the light beam from said recording medium; bias magnetic field generating means for applying a bias magnetic field onto said recording medium; and first magnetic field generating means for generating a first magnetic field, and second magnetic field generating means for generating a second magnetic field, the first and the second magnetic field generating means being associated with components of the recording/reproducing apparatus other than said bias magnetic field generating means, the first and the second magnetic fields being directed in directions opposite to one another onto that region of said recording medium which is irradiated with the light beam for minimizing interference with said bias magnetic field at said region.
Claim 3
Dependent Claim
32 words
The apparatus according to claim 1, wherein the surface of said recording medium is composed of a thin film of a magnetic material magnetized in a direction substantially perpendicular to the surface.
Claim 4
Dependent Claim
26 words
The apparatus according to claim 1, wherein one of said first and second magnetic field generating means includes a lens actuator for driving said focusing means.
Claim 5
Dependent Claim
26 words
The apparatus according to claim 1, wherein one of said first and second magnetic field generating means includes a pickup driver for driving said pickup means.
Claim 6
Dependent Claim
33 words
The apparatus according to claim 1, wherein one of said first and second magnetic field generating means includes clamp means for clamping said recording medium at a predetermined position by a magnetic attraction.
Claim 7
Dependent Claim
21 words
The apparatus according to claim 1, wherein said recording medium is formed into a disk-like shape having a rotational center thereof.
Claim 8
Dependent Claim
15 words
The apparatus according to claim 6, further comprising driving means for rotating said recording medium.
Claim 9
Dependent Claim
37 words
The apparatus according to claim 7, wherein one of said first and second magnetic field generating means includes clamp means arranged in said driving means for clamping said recording medium at a predetermined position by magnetic attraction.
Claim 10
Dependent Claim
36 words
The apparatus according to claim 7, wherein one of said first and second magnetic field generating means includes a magnetic sensor for detecting a rotational speed of said disc-like recording medium rotated about the rotational center.
Claim 11
Dependent Claim
164 words
An optomagnetic recording/reproducing apparatus, comprising: a light source for generating a light beam; focusing means for focusing the light beam emitted from said light source; a recording medium having a recording surface to be irradiated with the light beam focused by said focusing means; pickup means for detecting the light beam from said recording medium; bias magnetic field generating means for applying a bias magnetic field onto said recording medium; lens actuator means for generating a first magnetic field, so as to drive said focusing means, the first magnetic field being applied in a first direction perpendicular to the surface of the recording medium onto that region of the medium which is irradiated with the light beam; and magnetic field generating means for generating a second magnetic field so that said first and said second magnetic fields substantially cancel one another, said second magnetic fields being applied in a second direction opposite to said first direction onto said irradiated region of the recording medium.
Claim 12
Dependent Claim
164 words
An optomagnetic recording/reproducing apparatus, comprising: a light source for generating a light beam; focusing means for focusing the light beam emitted from said light source; a recording medium having a recording surface to be irradiated with the light beam focused by said focusing means; pickup means for detecting the light beam from said recording medium; bias magnetic field generating means for applying a bias magnetic field onto said recording medium; lens actuator means for generating a first magnetic field, so as to drive said focusing means, the first magnetic field being applied in a first direction perpendicular to the surface of the recording medium onto that region of the medium which is irradiated with the light beam; and magnetic field generating means for generating a second magnetic field so that said first and said second magnetic fields substantially cancel one another, said second magnetic fields being applied in a second direction opposite to said first direction onto said irradiated region of the recording medium.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |