US5629909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magneto-optical recording medium with initializing layer for initializing different regions in different directions
Assignee: Canon Inc
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Filing: 1996-02-08
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Granted: 1997-05-13
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Expires: 2016-02-08
Abstract
Abstract A magneto-optical recording medium consists of a plurality of magnetic layers, and at least one of the plurality of magnetic layers always maintains a magnetization orientation state in which magnetization is oriented in a given direction in a region, where the recording mark string is formed, on a central portion of a recording track, and magnetization is oriented in a direction anti-parallel to the given direction in regions at two sides of the region, where the recording mark string is formed, on side portions of the recording track. With this arrangement, even when recording laser power fluctuates or a tracking control error occurs during an optical modulation over-write operation, generation of an unerased portion of initially recorded information can be suppressed.
Inventors
- 👤 Tsutomu Shiratori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:12
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10502; G11B11/10504; G11B11/10506
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
249 words
A magneto-optical recording medium having at least first and second magnetic layers and being capable of overwriting a recording mark string recorded in a recording region of said first magnetic layer by using (i) a first kind of recording process in which the direction of magnetization of the first magnetic layer is oriented in a direction that is stable with respect to an exchange-coupling force of the second magnetic layer, which has been initialized, by a heating/cooling process in which the medium is heated to a first temperature, and (ii) a second kind of recording process in which the direction of magnetization of the second magnetic layer is reversed by a heating/cooling process in which the medium is heated to a second temperature and thereafter the direction of magnetization of the first magnetic layer is oriented in a direction that is stable with respect to the exchange-coupling force of the second magnetic layer, characterized in that said magneto-optical recording medium includes an initializing magnetic layer for initializing the direction of magnetization of the second magnetic layer, and wherein said initializing magnetic layer (i) initializes, in a first direction, the direction of magnetization in a first region of the second magnetic layer that corresponds to the recording region of the first magnetic layer for forming the recording mark string, and (ii) initializes, in a direction opposite to the first direction, the direction of magnetization in other regions of the second magnetic layer located on two sides of the first region.
Claim 2
Dependent Claim
249 words
A magneto-optical recording medium having at least first and second magnetic layers and being capable of overwriting a recording mark string recorded in a recording region of said first magnetic layer by using (i) a first kind of recording process in which the direction of magnetization of the first magnetic layer is oriented in a direction that is stable with respect to an exchange-coupling force of the second magnetic layer, which has been initialized, by a heating/cooling process in which the medium is heated to a first temperature, and (ii) a second kind of recording process in which the direction of magnetization of the second magnetic layer is reversed by a heating/cooling process in which the medium is heated to a second temperature and thereafter the direction of magnetization of the first magnetic layer is oriented in a direction that is stable with respect to the exchange-coupling force of the second magnetic layer, characterized in that said magneto-optical recording medium includes an initializing magnetic layer for initializing the direction of magnetization of the second magnetic layer, and wherein said initializing magnetic layer (i) initializes, in a first direction, the direction of magnetization in a first region of the second magnetic layer that corresponds to the recording region of the first magnetic layer for forming the recording mark string, and (ii) initializes, in a direction opposite to the first direction, the direction of magnetization in other regions of the second magnetic layer located on two sides of the first region.
Claim 3
Dependent Claim
22 words
A magneto-optical recording medium according to claim 1, wherein each of said magnetic layers consists of a rare earth-iron group amorphous alloy.
Claim 4
Dependent Claim
49 words
A magneto-optical recording medium according to claim 1, further comprising a transparent substrate which supports said first and second magnetic layers and said initializing magnetic layer and which is provided with a plurality of groove and land portions, wherein the recording mark string is formed on the land portions.
Claim 5
Dependent Claim
36 words
A magneto-optical recording medium according to claim 1, further comprising a transparent substrate which supports said first and second magnetic layers and said initializing magnetic layer and on which a format for sample servo is formed.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-05-12 | 2000-11-11 | 2001-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-05-12 | 2004-11-11 | 2005-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-05-12 | 2008-11-11 | 2009-05-13 | $7700.00 | Window Closed / Lapsed |