US5475657A
Expired / Lapsed
US
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Overwrite capable magnetooptial recording apparatus
Assignee: Nikon Corp
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Filing: 1993-07-16
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Granted: 1995-12-12
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Expires: 2013-07-16
Abstract
Abstract An overwrite capable magnetooptical recording apparatus comprises a moving magnetooptical recording medium to which is applied an initial magnetic field and a laser beam which irradiates the moving medium. The beam intensity is modulated, in accordance with binary data to be recorded, between a high beam intensity level that provides the medium with a first temperature suitable for forming one of a first bit having upward-magnetization and a second bit having downward-magnetization, and a low beam intensity level that provides the medium with a second temperature suitable for forming the other bit. A bias magnetic field is applied to a portion of the medium irradiated by the beam.
Inventors
- 👤 Masatoshi Sato
- 👤 Jun Saito
- 👤 Hideki Akasaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:25
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10517; G11B11/10519; G11B11/10504; G11B11/10506; G11B11/10521; G11B11/10582; G11B11/10586; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S430/00; Y10S430/146; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12951
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
148 words
An overwrite capable magnetooptical recording apparatus characterized by comprising: (a) means for moving a magnetooptical recording medium; (b) initial field applying means for applying an initial magnetic field to the moving medium; (c) a laser beam source for radiating a laser beam to the moving medium; (d) means for pulse modulating a beam intensity of the laser beam, before the beam reaches the medium, in accordance with binary data to be recorded to obtain (1) high level that provides, to said medium, a first temperature suitable for forming one of a first bit having upward-magnetization and a second bit having downward-magnetization, and to obtain (2) low level that provides, to said medium, a second temperature suitable for forming the other of said first and second bits; and (e) bias field applying means for applying a bias magnetic field to a portion of the medium irradiated by the beam.
Claim 2
Dependent Claim
148 words
An overwrite capable magnetooptical recording apparatus characterized by comprising: (a) means for moving a magnetooptical recording medium; (b) initial field applying means for applying an initial magnetic field to the moving medium; (c) a laser beam source for radiating a laser beam to the moving medium; (d) means for pulse modulating a beam intensity of the laser beam, before the beam reaches the medium, in accordance with binary data to be recorded to obtain (1) high level that provides, to said medium, a first temperature suitable for forming one of a first bit having upward-magnetization and a second bit having downward-magnetization, and to obtain (2) low level that provides, to said medium, a second temperature suitable for forming the other of said first and second bits; and (e) bias field applying means for applying a bias magnetic field to a portion of the medium irradiated by the beam.
Claim 3
Dependent Claim
42 words
An apparatus according to claim 1, wherein both said bias field applying means and said initial field applying means are fixed applying means having a length corresponding to that along a radial direction of a recording region of a disk-shaped recording medium.
Claim 4
Dependent Claim
20 words
An apparatus according to claim 1, wherein said bias field applying means also serves as said initial field applying means.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-12-11 | 1999-06-12 | 1999-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-11 | 2003-06-12 | 2003-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-11 | 2007-06-12 | 2007-12-12 | $7700.00 | Window Closed / Lapsed |