Patent US4495242A successfully refreshed from Google Patents.
US4495242A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-04-01
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Granted: 1985-01-22
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Expires: 2002-04-01
Abstract
Abstract A nonbinder type of magnetic recording medium is disclosed. The binder is comprised of a non-magnetic support having thereon, in sequence, a thin magnetic metal film laminated using the evaporation technique and a protecting film, with the thin magnetic metal film converted in its surface part alone to a metal oxide layer by being oxidized with oxygen plasma, to a metal nitride layer by being nitrided with nitrogen plasma or to a glow discharge-processed layer. The protecting film includes a high molecular weight compound, a higher fatty acid, a fatty acid ester or a combination thereof, laminated on the metal oxide layer, the metal nitride layer or the glow discharge-processed layer.
Inventors
- 👤 Yoshihiro Arai
- 👤 Akira Nahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:04
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/64; G11B5/66; G11B5/672; G11B5/84; G11B5/851; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
107 words
A magnetic recording medium, comprising: a non-magnetic support; a thin film of a magnetic metal evaporated on the non-magnetic support, wherein the surface part of the film is converted to the metal oxide layer, wherein the total thickness of the thin film of magnetic metal ranges from about 200 Å to 20,000 Å, and the thickness of the metal oxide layer is less than 300 Å; and a protecting film composed of a high molecular weight compound, a higher fatty acid, a fatty acid ester or a combination thereof, laminated on said metal oxide layer, wherein the thickness of the protecting film is less than 500 Å.
Claim 2
Dependent Claim
107 words
A magnetic recording medium, comprising: a non-magnetic support; a thin film of a magnetic metal evaporated on the non-magnetic support, wherein the surface part of the film is converted to the metal oxide layer, wherein the total thickness of the thin film of magnetic metal ranges from about 200 Å to 20,000 Å, and the thickness of the metal oxide layer is less than 300 Å; and a protecting film composed of a high molecular weight compound, a higher fatty acid, a fatty acid ester or a combination thereof, laminated on said metal oxide layer, wherein the thickness of the protecting film is less than 500 Å.
Claim 3
Dependent Claim
107 words
A magnetic recording medium, comprising: a non-magnetic support; a thin film of a magnetic metal evaporated on the non-magnetic support, wherein the surface part of the film is converted to a metal nitride layer, wherein the total thickness of the thin film of magnetic metal ranges from about 200 Å to 20,000 Å, and the thickness of the metal nitride layer is less than 300 Å; and a protecting film composed of a high molecular weight compound, a higher fatty acid, and a fatty acid ester or a combination thereof, laminated on said nitride layer, wherein the thickness of the protecting film is less than 500 Å.
Claim 4
Dependent Claim
107 words
A magnetic recording medium, comprising: a non-magnetic support; a thin film of a magnetic metal evaporated on the non-magnetic support, wherein the surface part of the film is converted to a metal nitride layer, wherein the total thickness of the thin film of magnetic metal ranges from about 200 Å to 20,000 Å, and the thickness of the metal nitride layer is less than 300 Å; and a protecting film composed of a high molecular weight compound, a higher fatty acid, and a fatty acid ester or a combination thereof, laminated on said nitride layer, wherein the thickness of the protecting film is less than 500 Å.
Claim 5
Dependent Claim
92 words
A magnetic recording medium, comprising a non-magnetic support; a thin film of a magnetic layer evaporated on the non-magnetic support, wherein the surface part of the film is converted to glow discharge-process layer, wherein the thickness of the thin film of magnetic metal ranges from about 200 Å to 20,000 Å; and a protecting film composed of a high molecular weight compound, a higher fatty acid, a fatty acid ester or a combination thereof, laminated on the glow discharge-process layer, wherein the thickness of the protecting film is less than 500 Å.
Claim 6
Dependent Claim
92 words
A magnetic recording medium, comprising a non-magnetic support; a thin film of a magnetic layer evaporated on the non-magnetic support, wherein the surface part of the film is converted to glow discharge-process layer, wherein the thickness of the thin film of magnetic metal ranges from about 200 Å to 20,000 Å; and a protecting film composed of a high molecular weight compound, a higher fatty acid, a fatty acid ester or a combination thereof, laminated on the glow discharge-process layer, wherein the thickness of the protecting film is less than 500 Å.
Claim 7
Dependent Claim
31 words
A magnetic recording medium as claimed in any of claims 1, 2 or 3, wherein said magnetic metal film has a thickness of from about 500 Å to about 10,000 Å.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-22 | 1988-07-23 | 1989-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-22 | 1992-07-23 | 1993-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-22 | 1996-07-23 | 1997-01-22 | $7700.00 | Window Closed / Lapsed |