Patent US4889767A successfully refreshed from Google Patents.
US4889767A
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US
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1987-04-23
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Granted: 1989-12-26
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Expires: 2007-04-23
Abstract
Abstract In a magnetic recording medium wherein a metal thin film magnetic layer and a topcoat layer of an organic fluorine compound are formed on a nonmagnetic substrate, the surface of the magnetic layer is plasma treated or plasma oxidized, enhancing the bond between the adjoining layers. A protective film of carbon may be disposed between the magnetic layer and the topcoat, with the surface of the protective carbon film plasma treated. Instead, a protective film of plasma-polymerized organometallic compound may be used.
Inventors
- 👤 Kenji Yokoyama
- 👤 Masatoshi Nakayama
- 👤 Toru Shimozawa
- 👤 Kunihiro Ueda
- 👤 Fumio Maruta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/722; G11B5/726; G11B5/7262; G11B5/7264; G11B5/7266; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
80 words
In a magnetic recording medium comprising a nonmagnetic substrate having opposed major surfaces, a metal thin film magnetic layer on one major surface of the substrate, a protective film of carbon on the magnetic layer, and a topcoat layer 3-300 Å thick comprising an organic fluorine compound on the protective film, the improvement wherein the surface of any underlying layer to which said protective carbon film is contiguous and optionally, the surface of said protective carbon film are plasma treated.
Claim 2
Dependent Claim
80 words
In a magnetic recording medium comprising a nonmagnetic substrate having opposed major surfaces, a metal thin film magnetic layer on one major surface of the substrate, a protective film of carbon on the magnetic layer, and a topcoat layer 3-300 Å thick comprising an organic fluorine compound on the protective film, the improvement wherein the surface of any underlying layer to which said protective carbon film is contiguous and optionally, the surface of said protective carbon film are plasma treated.
Claim 3
Dependent Claim
30 words
The magnetic recording medium of claim 1 wherein the topcoat comprises at least one member selected from carboxyperfluoropolyethers and salts and esters thereof, and perfluoroethylene polymers, and a mixture thereof.
Claim 4
Dependent Claim
18 words
The magnetic recording medium of claim 1 wherein the topcoat is a coated or gas phase deposited film.
Claim 5
Dependent Claim
21 words
The magnetic recording medium of claim 3 wherein the gas phase deposited film is formed by evaporation, sputtering or ion plating.
Claim 6
Dependent Claim
33 words
The magnetic recording medium of claim 1 wherein the metal thin film magnetic layer predominantly comprises cobalt and at least one optional member selected from the group consisting of Ni, Cr, and P.
Claim 7
Dependent Claim
25 words
The magnetic recording medium of claim 1 or 2 which further comprises an undercoat layer between the substrate and the metal thin film magnetic layer.
Claim 8
Dependent Claim
35 words
The magnetic recording medium of claim 1 which further comprises an intermediate layer of a nonmagnetic metal disposed contiguous to the surface of the metal thin film magnetic layer on the side of the substrate.
Claim 9
Dependent Claim
15 words
The magnetic recording medium of claim 3 wherein the undercoat layer has an irregular surface.
Claim 10
Dependent Claim
15 words
The magnetic recording medium of claim 1 wherein the substrate is a rigid nonmagnetic substrate.
Claim 11
Dependent Claim
23 words
The magnetic recording medium of any one of claim 1-5 or 7, wherein the surface of said protective carbon film is plasma treated.
Claim 12
Dependent Claim
63 words
A magnetic recording medium comprising a nonmagnetic substrate having opposed major surfaces, a metal thin film magnetic layer on one major surface of the substrate, a protective layer of non-magnetic metal on said magnetic layer, a plasma-polymerized film of an organometallic compound on the protective non-magnetic layer, and a topcoat layer 3-300 Å thick comprising an organic fluorine compound on the plasma-polymerized film.
Claim 13
Dependent Claim
63 words
A magnetic recording medium comprising a nonmagnetic substrate having opposed major surfaces, a metal thin film magnetic layer on one major surface of the substrate, a protective layer of non-magnetic metal on said magnetic layer, a plasma-polymerized film of an organometallic compound on the protective non-magnetic layer, and a topcoat layer 3-300 Å thick comprising an organic fluorine compound on the plasma-polymerized film.
Claim 14
Dependent Claim
16 words
The magnetic recording medium of claim 11 wherein the metal thin film magnetic layer comprises cobalt.
Claim 15
Dependent Claim
26 words
The magnetic recording medium of claim 11 wherein the plasma-polymerized organometallic film has an atomic ratio M/C of metal to carbon atom of 0.05:1 to 1.0:1.
Claim 16
Dependent Claim
20 words
The magnetic recording medium of claim 11 wherein the plasma-polymerized organometallic film has a thickness of 30 to 300 Å.
Claim 17
Dependent Claim
30 words
The magnetic recording medium of claim 11 wherein the topcoat comprises at least one member selected from carboxyperfluoropolyethers and salts and esters thereof, and perfluoroethylene polymers, and a mixture thereof.
Claim 18
Dependent Claim
18 words
The magnetic recording medium of claim 11 wherein the topcoat is a coated or gas phase deposited film.
Claim 19
Dependent Claim
21 words
The magnetic recording medium of claim 16 wherein the gas phase deposited film is formed by evaporation, sputtering or ion plating.
Claim 20
Dependent Claim
23 words
The magnetic recording medium of claim 11 which further comprises an undercoat layer between the substrate and the metal thin film magnetic layer.
Claim 21
Dependent Claim
35 words
The magnetic recording medium of claim 11 which further comprises an intermediate layer of a nonmagnetic metal disposed contiguous to the surface of the metal thin film magnetic layer on the side of the substrate.
Claim 22
Dependent Claim
19 words
The magnetic recording medium of claim 11 wherein the surface of said protective nonmagnetic metal layer is plasma treated.
Claim 23
Dependent Claim
23 words
The magnetic recording medium of claim 11 which further comprises a protective layer of carbon between the plasma-polymerized organometallic film and the topcoat.
Claim 24
Dependent Claim
18 words
The magnetic recording medium of claim 21 wherein the surface of said protective carbon layer is plasma treated.
Claim 25
Dependent Claim
15 words
The magnetic recording medium of claim 18 wherein the undercoat layer has an irregular surface.
Claim 26
Dependent Claim
15 words
The magnetic recording medium of claim 11 wherein the substrate is a rigid nonmagnetic substrate.
Claim 27
Dependent Claim
75 words
A magnetic recording medium comprising a nonmagnetic substrate having opposed major surfaces, a metal thin film magnetic layer disposed on one major surface of the substrate and having opposed surfaces adjacent to and remote from said substrate, the magnetic layer surface remote from said substrate being plasma oxidized, a protective layer of non-magnetic metal on said magnetic layer, and a topcoat layer 3-30 Å thick comprising an organic fluorine compound on the protective non-magnetic layer.
Claim 28
Dependent Claim
75 words
A magnetic recording medium comprising a nonmagnetic substrate having opposed major surfaces, a metal thin film magnetic layer disposed on one major surface of the substrate and having opposed surfaces adjacent to and remote from said substrate, the magnetic layer surface remote from said substrate being plasma oxidized, a protective layer of non-magnetic metal on said magnetic layer, and a topcoat layer 3-30 Å thick comprising an organic fluorine compound on the protective non-magnetic layer.
Claim 29
Dependent Claim
16 words
The magnetic recording medium of claim 25 wherein the metal thin film magnetic layer comprises cobalt.
Claim 30
Dependent Claim
31 words
The magnetic recording medium of claim 26 wherein in the metal thin film magnetic layer further comprising oxygen, the average atomic ratio of oxygen to cobalt ranges from 0.01 to 0.3.
Claim 31
Dependent Claim
31 words
The magnetic recording medium of claim 26 the metal thin film magnetic layer further comprising oxygen, wherein oxygen is rich at a surface region of the metal thin film magnetic layer.
Claim 32
Dependent Claim
81 words
The magnetic recording medium of claim 26 wherein in the metal thin film magnetic layer further comprising oxygen, the average atomic ratio of oxygen to cobalt in the region of the magnetic layer that extends from its surface remote from said substrate to 1/10th of its thickness is at least 3 times the average atomic ratio of oxygen to cobalt in the region of the magnetic layer that extends from its surface adjacent to said substrate to 1/10th of its thickness.
Claim 33
Dependent Claim
30 words
The magnetic recording medium of claim 25 wherein the topcoat comprises at least one member selected from carboxyperfluoropolyethers and salts and esters thereof, and perfluoroethylene polymers, and a mixture thereof.
Claim 34
Dependent Claim
20 words
The magnetic recording medium of claim 25 or 30 wherein the topcoat is a coated or gas phase deposited film.
Claim 35
Dependent Claim
21 words
The magnetic recording medium of claim 31 wherein the gas phase deposited film is formed by evaporation, sputtering or ion plating.
Claim 36
Dependent Claim
23 words
The magnetic recording medium of claim 25 which further comprises an undercoat layer between the substrate and the metal thin film magnetic layer.
Claim 37
Dependent Claim
33 words
The magnetic recording medium of claim 25 which further comprises an intermediate layer of a nonmagnetic metal disposed contiguous to the surface of the metal thin film magnetic layer adjacent to the substrate.
Claim 38
Dependent Claim
19 words
The magnetic recording medium of claim 29 wherein the surface of said protective nonmagnetic metal layer is plasma treated.
Claim 39
Dependent Claim
24 words
The magnetic recording medium of claim 29 which further comprises a protective layer of carbon between the protective nonmagnetic metal layer and the topcoat.
Claim 40
Dependent Claim
18 words
The magnetic recording medium of claim 36 wherein the surface of said protective carbon layer is plasma treated.
Claim 41
Dependent Claim
15 words
The magnetic recording medium of claim 33 wherein the undercoat layer has an irregular surface.
Claim 42
Dependent Claim
15 words
The magnetic recording medium of claim 25 wherein the substrate is a rigid nonmagnetic substrate.
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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) | 1992-12-25 | 1993-06-26 | 1993-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-25 | 1997-06-26 | 1997-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-25 | 2001-06-26 | 2001-12-26 | $7700.00 | Window Closed / Lapsed |