US4761330A
Expired / Lapsed
US
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Optomagnetic recording medium
Assignee: Yamaha Corp
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Filing: 1986-04-01
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Granted: 1988-08-02
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Expires: 2006-04-01
Abstract
Abstract In production of an optomagnetic recording medium having a porous anode oxidized coat on a base plate, a thin film of magnetic material of high saturated magnetization is developed after grinding and etching following formation of the anode oxidized coat in order to increase the effective reflection plane, thereby greatly raising accuracy of detection of the polarization angle at reading-out of signals.
Inventors
- 👤 Tadao Tokushima
- 👤 Makato Shiraki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:11
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/74; G11B5/743; B; B82; B82Y; B82Y10/00; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10593; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249967; Y10T428/24997; Y10T428/249987; Y10T428/24999; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
165 words
An optomagnetic recording medium, comprising: a base plate comprising aluminum; an anode oxidized coat formed on said base plate, said coat having pores therein extending inwardly from an upper surface of said oxidized coat such that each said pore has an open end at said upper surface; a first magnetic material packed in said pores of said anode oxidized coat; and a thin film of a second magnetic material having a saturation magnetization effective to allow magnetic flux to penetrate from said first magnetic material to an upper surface of said second magnetic material, said second material covering said open end of said pores and being accessible by light emitted from a source above and spaced from said upper surface of said anode oxidized coat; said film having a thickness effective to prevent penetration of light into said oxidized coat, yet being sufficiently thin to permit anisotropy in the vertical direction and to prevent interference between magnetic fluxes from said magnetic material in adjacent pores.
Claim 2
Dependent Claim
165 words
An optomagnetic recording medium, comprising: a base plate comprising aluminum; an anode oxidized coat formed on said base plate, said coat having pores therein extending inwardly from an upper surface of said oxidized coat such that each said pore has an open end at said upper surface; a first magnetic material packed in said pores of said anode oxidized coat; and a thin film of a second magnetic material having a saturation magnetization effective to allow magnetic flux to penetrate from said first magnetic material to an upper surface of said second magnetic material, said second material covering said open end of said pores and being accessible by light emitted from a source above and spaced from said upper surface of said anode oxidized coat; said film having a thickness effective to prevent penetration of light into said oxidized coat, yet being sufficiently thin to permit anisotropy in the vertical direction and to prevent interference between magnetic fluxes from said magnetic material in adjacent pores.
Claim 3
Dependent Claim
29 words
The optomagnetic recording medium according to claim 1 in which said first magnetic material comprises a metal selected from the group consisting of iron, nickel, cobalt and their alloys.
Claim 4
Dependent Claim
29 words
The optomagnetic recording medium according to claim 1 in which said second magnetic material comprises a metal selected from the group consisting of iron, nickel, cobalt and alloys thereof.
Claim 5
Dependent Claim
25 words
The optomagnetic recording medium according to claim 1 in which the thickness of said thin film is in a range from 5 to 100 nm.
Claim 6
Dependent Claim
22 words
The optomagnetic recording medium according to claim 1 in which the saturation magnetization of said second magnetic material is 0.5T or larger.
Claim 7
Dependent Claim
17 words
The optomagnetic recording medium according to claim 5 in which said saturation magnetization is 1.OT or larger.
Claim 8
Dependent Claim
23 words
The optomagnetic recording medium according to claim 1 in which the thickness of said anode oxidized coat is not more than 6 μm.
Claim 9
Dependent Claim
19 words
The optomagnetic recording medium according to claim 7 in which said thickness is not more than about 3 μm.
Claim 10
Dependent Claim
27 words
The optomagnetic recording medium according to claim 1 in which the diameter of said pores in said anode oxidized coat not more than about is 100 nm.
Claim 11
Dependent Claim
27 words
The optomagnetic recording medium according to claim 9 in which the ratio of the depth of said pores to said diameter is no less than about 10.
Claim 12
Dependent Claim
163 words
An optomagnetic recording medium comprising: (a) a base plate comprising aluminum; (b) an anode oxidized coat formed on a face of said base plate, said anode oxidized coat having pores therein extending inwardly from an upper surface of said oxidized coat such that each said pore has an open end at said upper surface; (c) a first magnetic material packed in said pores of said anode oxidized coat; and (d) a thin film of a second magnetic material covering said open ends of said pores and the portion of said upper surface of said oxidized coat immediately surrounding said open ends; said second magnetic material being accessible by light emitted from a source above and spaced from said upper surface of said anode oxidized coat and having saturation magnetization effective to allow magnetic flux to penetrate from said first magnetic material to an upper surface of said second magnetic material; said film having a thickness from about 5 nm to about 100 nm.
Claim 13
Dependent Claim
163 words
An optomagnetic recording medium comprising: (a) a base plate comprising aluminum; (b) an anode oxidized coat formed on a face of said base plate, said anode oxidized coat having pores therein extending inwardly from an upper surface of said oxidized coat such that each said pore has an open end at said upper surface; (c) a first magnetic material packed in said pores of said anode oxidized coat; and (d) a thin film of a second magnetic material covering said open ends of said pores and the portion of said upper surface of said oxidized coat immediately surrounding said open ends; said second magnetic material being accessible by light emitted from a source above and spaced from said upper surface of said anode oxidized coat and having saturation magnetization effective to allow magnetic flux to penetrate from said first magnetic material to an upper surface of said second magnetic material; said film having a thickness from about 5 nm to about 100 nm.
Claim 14
Dependent Claim
18 words
The optomagnetic recording medium according to claim 11, wherein said base plate comprises an aluminum predominant metallic material.
Claim 15
Dependent Claim
23 words
The optomagnetic recording medium according to claim 11, wherein said second magnetic material substantially covers said upper face of said anode oxidized coat.
Claim 16
Dependent Claim
36 words
The optomagnetic recording medium according to claim 11, wherein said second magnetic material has sufficient saturation magnetization to substantially preserve magnetic flux intensity from said first magnetic material to the upper surface of said second material.
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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) | 1991-08-02 | 1992-02-01 | 1992-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-02 | 1996-02-01 | 1996-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-02 | 2000-02-01 | 2000-08-02 | $7700.00 | Window Closed / Lapsed |