US4565734A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1984-03-14
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Granted: 1986-01-21
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Expires: 2004-03-14
Abstract
Abstract A magnetic recording medium comprises a non-magnetic substrate, a thin magnetic metal film layer overlaid on the substrate, a metallic oxide layer formed on the surface of the thin magnetic metal film layer, and a polymer film formed by plasma polymerization. The polymer film is overlaid on the metallic oxide layer to improve the corrosion resistance and durability of the magnetic recording medium.
Inventors
- 👤 Yoshihiro Arai
- 👤 Akira Nahara
- 👤 Kiyotaka Fukino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:59
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/722; G11B5/726; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/24975; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T428/31678; Y10T428/31692; Y10T428/31699
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
48 words
A magnetic recording medium comprising a nonmagnetic substrate, a thin magnetic metal film layer provided on the surface thereof with a metallic oxide layer, and a polymer film formed by plasma polymerization which is overlaid on said metallic oxide layer so as to cover said metallic oxide layer.
Claim 2
Dependent Claim
48 words
A magnetic recording medium comprising a nonmagnetic substrate, a thin magnetic metal film layer provided on the surface thereof with a metallic oxide layer, and a polymer film formed by plasma polymerization which is overlaid on said metallic oxide layer so as to cover said metallic oxide layer.
Claim 3
Dependent Claim
26 words
A magnetic recording medium as defined in claim 1 wherein said non-magnetic substrate is a flexible plastic film exhibiting surface roughness of 0.012 μm or less.
Claim 4
Dependent Claim
37 words
A magnetic recording medium as defined in claim 1 wherein said thin magnetic metal film layer is composed of a material selected from the group consisting of cobalt, a cobalt alloy, and a cobalt alloy containing oxygen.
Claim 5
Dependent Claim
23 words
A magnetic recording medium as defined in claim 1 wherein said thin magnetic metal film layer has an obliquely deposited columnar grain structure.
Claim 6
Dependent Claim
23 words
A magnetic recording medium as defined in claim 1 wherein said thin magnetic metal film layer has a thickness of about 1,400 Å.
Claim 7
Dependent Claim
28 words
A magnetic recording medium as defined in claim 1 wherein said metallic oxide layer has a thickness within the range of about 50 Å to about 200 Å.
Claim 8
Dependent Claim
29 words
A magnetic recording medium as defined in claim 1 wherein said polymer film formed by plasma polymerization has a thickness within the range of 20 Å to 800 Å.
Claim 9
Dependent Claim
38 words
A magnetic recording medium as defined in claim 1 wherein said polymer film formed by plasma polymerization is prepared by polymerizing plasma of an organic monomer gas selected from the group consisting of methane, ethylene, tetrafluoroethylene, and octafluorocyclobutane.
Claim 10
Dependent Claim
28 words
A magnetic recording medium as defined in claim 1 wherein a lubricating layer is overlaid at least on the surface of said polymer film formed by plasma polymerization.
Claim 11
Dependent Claim
49 words
A magnetic recording medium as defined in claim 9 wherein said lubricating layer is composed of a material selected from the group consisting of a higher fatty acid, an ester of a fatty acid, and a combination of a higher fatty acid with an ester of a fatty acid.
References Cited (Backward Citations)
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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) | 1989-01-20 | 1989-07-22 | 1990-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-20 | 1993-07-22 | 1994-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-20 | 1997-07-22 | 1998-01-21 | $7700.00 | Window Closed / Lapsed |