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US5422865A
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Light modulation method for magneto-optical recording device
Assignee: Sharp Corp
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Filing: 1993-12-07
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Granted: 1995-06-06
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Expires: 2013-12-07
Abstract
Abstract A magneto-optical recording method includes the steps of applying an external magnetic field perpendicularly onto the magnetic thin film with perpendicular magnetization of a magneto-optical recording medium and projecting a light beam onto the magneto-optical recording medium; and modulating the intensity of the light beam between the first light intensity and the second light intensity in response to the information to be recorded while shifting a spot of the light beam, thereby recording information. In the above method, the first light intensity is set such that by reducing the coercive force of the magnetic thin film with perpendicular magnetization, a magnetic domain is formed on the magnetic thin film with perpendicular magnetization, and that the magnetic domain is moved as the spot of the light beam is shifted. The second light intensity is set such that by increasing the coercive force of the magnetic thin film with perpendicular magnetization, the magnetic domain is fixed to the position.
Inventors
- 👤 Hiroyuki Katayama
- 👤 Junji Hirokane
- 👤 Junichiro Nakayama
- 👤 Akira Takahashi
- 👤 Kenji Ohta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:10
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10502; G11B11/10504; G11B11/10506; G11B11/10517; G11B11/10519; G11B11/10521
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
149 words
A magneto-optical recording method comprising the steps of: applying an external magnetic field perpendicularly onto a magnetic thin film with perpendicular magnetization of a magneto-optical recording medium and projecting a light beam onto said magneto-optical recording medium; and modulating an intensity of the light beam between a first light intensity and a second light intensity in response to information to be recorded while a spot of the light beam is being shifted, wherein the first light intensity is set such that by reducing a coercive force of the magnetic thin film with perpendicular magnetization, a magnetic domain is formed on the magnetic thin film with perpendicular magnetization and that the magnetic domain moves as the spot of the light beam is shifted, and the second light intensity is set such that by increasing the coercive force of the magnetic thin film with perpendicular magnetization, the magnetic domain is fixed.
Claim 2
Dependent Claim
149 words
A magneto-optical recording method comprising the steps of: applying an external magnetic field perpendicularly onto a magnetic thin film with perpendicular magnetization of a magneto-optical recording medium and projecting a light beam onto said magneto-optical recording medium; and modulating an intensity of the light beam between a first light intensity and a second light intensity in response to information to be recorded while a spot of the light beam is being shifted, wherein the first light intensity is set such that by reducing a coercive force of the magnetic thin film with perpendicular magnetization, a magnetic domain is formed on the magnetic thin film with perpendicular magnetization and that the magnetic domain moves as the spot of the light beam is shifted, and the second light intensity is set such that by increasing the coercive force of the magnetic thin film with perpendicular magnetization, the magnetic domain is fixed.
Claim 3
Dependent Claim
53 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium comprises a substrate a property that light can be transmitted therethrough, whereon a first dielectric film, a recording layer composed of a magnetic thin film with perpendicular magnetization and a second dielectric film are formed in this order.
Claim 4
Dependent Claim
46 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium comprises a glass substrate whereon a first dielectric film made of AlN, a recording layer made of Gd0.27Dy0.18Fe0.55 and a second dielectric film made of AlN are formed in this order.
Claim 5
Dependent Claim
46 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium comprises a glass substrate whereon a first dielectric film made of AlN, a recording layer made of Gd0.20Tb0.20Fe0.60 and a second dielectric film made of AlN are formed in this order.
Claim 6
Dependent Claim
46 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium comprises a glass substrate whereon a first dielectric film made of AlN, a recording layer made of Gd0.28Dy0.19Fe0.53 and a second dielectric film made of AlN are formed in this order.
Claim 7
Dependent Claim
57 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium comprises a substrate having a property that light can be transmitted therethrough, whereon a first dielectric film, a recording layer composed of a magnetic thin film with perpendicular magnetization, a second dielectric film and a reflective film are formed in this order.
Claim 8
Dependent Claim
52 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium comprises a glass substrate whereon a first dielectric film made of AlN, a recording layer made of Gd0.29Dy0.18Fe0.53, a second dielectric film made of AlN and a reflective film made of AlN are formed in this order.
Claim 9
Dependent Claim
78 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium comprises a substrate having a property that light can be transmitted therethrough, whereon a first dielectric film, a readout layer composed of a magnetic thin film with perpendicular magnetization made of a magnetic substance having a large magnetic Kerr rotation angle, a recording layer composed of a magnetic thin film with perpendicular magnetization and a second dielectric film are formed in this order.
Claim 10
Dependent Claim
52 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium comprises a glass substrate whereon a first dielectric film made of AlN, a readout layer made of Dy0.46Fe0.45Co0.09, a recording layer made of Gd0.28Dy0.19Fe0.53 and a second dielectric film made of AlN are formed in this order.
Claim 11
Dependent Claim
19 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium is a magneto-optical disk.
Claim 12
Dependent Claim
19 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium is a magneto-optical tape.
Claim 13
Dependent Claim
19 words
The magneto-optical recording method as set forth in claim 1, wherein said magneto-optical recording medium is a magneto-optical card.
References Cited (Backward Citations)
US4939717A
Cited
US5038338A
Cited
US5257256A
Cited
US5144601A
Cited
JPH01311440A
Cited
JPH04146543A
Cited
JPH04325946A
Cited
JPH04355236A
Cited
JPH05151638A
Cited
JPH05182272A
Cited
JPH05290435A
Cited
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| 3.5 Years (Year 4) | 1998-06-05 | 1998-12-05 | 1999-06-06 | $2000.00 | Window Closed / Lapsed |
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