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Patent US4816334A successfully refreshed from Google Patents.
US4816334A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1987-04-03
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Granted: 1989-03-28
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Expires: 2007-04-03
Abstract
Abstract In a magnetic recording medium wherein a metal thin film magnetic layer, a protective film or carbon, and a topcoat layer are formed on a rigid substrate in this order, the topcoat layer is from an organic fluorine compound by gas phase deposition.
Inventors
- 👤 Kenji Yokoyama
- 👤 Masatoshi Nakayama
- 👤 Fumio Maruta
- 👤 Kunihiro Ueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:20
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/725; G11B5/7253; G11B5/7257; 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; Y10T428/30; Y10T428/31504; Y10T428/3154; Y10T428/31544
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
112 words
A magnetic recording medium comprising: a rigid substrate, a metal thin film magnetic layer on the substrate, a protective film of carbon on the magnetic layer wherein the film at its surface is plasma treated, and a topcoat layer of 3 to 300 Å of an organic fluorine compound formed on the protective film by gas phase deposition, wherein the organic fluorine compound is at least one member selected from the group consisting of (1) perfluoropolyethers; (2) carboxy perfluoropolyethers and salts and esters thereof; and (3) fluorocarbon resins selected from polytetrafluoroethylene of molecular weight of 1,000 to 10,000, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-ethylene copolymers, tetrafluoroethylene-perfluoro-alkylvinyl ether copolymers and chlorotrifluoroethylene-ethylene copolymers.
Claim 2
Dependent Claim
112 words
A magnetic recording medium comprising: a rigid substrate, a metal thin film magnetic layer on the substrate, a protective film of carbon on the magnetic layer wherein the film at its surface is plasma treated, and a topcoat layer of 3 to 300 Å of an organic fluorine compound formed on the protective film by gas phase deposition, wherein the organic fluorine compound is at least one member selected from the group consisting of (1) perfluoropolyethers; (2) carboxy perfluoropolyethers and salts and esters thereof; and (3) fluorocarbon resins selected from polytetrafluoroethylene of molecular weight of 1,000 to 10,000, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-ethylene copolymers, tetrafluoroethylene-perfluoro-alkylvinyl ether copolymers and chlorotrifluoroethylene-ethylene copolymers.
Claim 3
Dependent Claim
27 words
The magnetic recording medium of claim 1 which further comprises a nonmagnetic metal protective layer between the metal thin film magnetic layer and the carbon protective film.
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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) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |