Patent US4925733A successfully refreshed from Google Patents.
US4925733A
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Magnetic recording medium
Assignee: Canon Inc
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Filing: 1988-03-28
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Granted: 1990-05-15
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Expires: 2008-03-28
Abstract
Abstract A magnetic recording medium with a recording layer composed of a magnetic film formed on a substrate, in which an intermediate layer and a plasma-polymerized film are formed in succession on the recording layer.
Inventors
- 👤 Hiroyuki Imataki
- 👤 Mizuho Hiraoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:56
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/72; G11B5/726; G11B5/7262; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/3154; Y10T428/31544
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
117 words
A magnetic recording medium, comprising: a substrate; a recording layer composed of a magnetic film formed on said substrate; an intermediate layer for protecting said magnetic film from monomer gas during plasma polymerization, said intermediate layer formed over said recording layer by either vacuum evaporation or sputtering and being composed of Al 2 O 3 , BaO, BeO, CeO 2 , In 2 O 3 , SiO 2 , SiO, SnO 2 , Ta 2 O 5 , TiO 2 , ThO 2 , ZrO 2 , MgF 2 , CeF 4 , LaF 3 or a mixture of two or more of the foregoing compounds; and an anticorrosive layer formed on said intermediate layer by plasma-polymerization.
Claim 2
Dependent Claim
117 words
A magnetic recording medium, comprising: a substrate; a recording layer composed of a magnetic film formed on said substrate; an intermediate layer for protecting said magnetic film from monomer gas during plasma polymerization, said intermediate layer formed over said recording layer by either vacuum evaporation or sputtering and being composed of Al 2 O 3 , BaO, BeO, CeO 2 , In 2 O 3 , SiO 2 , SiO, SnO 2 , Ta 2 O 5 , TiO 2 , ThO 2 , ZrO 2 , MgF 2 , CeF 4 , LaF 3 or a mixture of two or more of the foregoing compounds; and an anticorrosive layer formed on said intermediate layer by plasma-polymerization.
Claim 3
Dependent Claim
23 words
A magnetic recording medium according to claim 1, wherein said intermediate layer has a thickness in a range from 60 to 10,000 Å.
Claim 4
Dependent Claim
20 words
A magnetic recording medium according to claim 2, wherein said intermediate layer has a thickness less than approximately 5,000 Å.
Claim 5
Dependent Claim
19 words
A magnetic recording medium according to claim 1, wherein said anticorrosive layer film is formed from a fluorinated monomer.
Claim 6
Dependent Claim
31 words
A magnetic recording medium according to claim 4, wherein said anticorrosive layer film is formed from tetrafluoroethylene, hexafluoropropene, hexafluoro-2-butyne, hexafluoro-1,3-butadiene, hexafluorobenzene, octafluoro-2-butene, octafluorocyclobutane, chlorotrifluoroethylene, trifluoroethyne, hexafluoropropylene, vinyl fluoride or vinylidene fluoride.
Claim 7
Dependent Claim
19 words
A magnetic recording medium according to claim 1, wherein said anticorrosive layer film is formed from a hydrocarbon monomer.
Claim 8
Dependent Claim
22 words
A magnetic recording medium according to claim 6, wherein said anticorrosive layer film is formed from ethylene, acetylene, methane, styrene or benzene.
Claim 9
Dependent Claim
25 words
A magnetic recording medium according to claim 1, wherein said anticorrosive layer film has a thickness in a range form 50 Å to 4000 Å.
Claim 10
Dependent Claim
24 words
A magnetic recording medium according to claim 1, further comprising a second said anticorrosive layer film formed between said substrate and said magnetic film.
Claim 11
Dependent Claim
17 words
A magnetic recording medium according to claim 9, wherein said substrate is composed of polymethyl methacrylate (PMMA).
Claim 12
Dependent Claim
23 words
A magnetic recording medium according to claim 1, wherein said anticorrosive layer film is formed from a monomer by capacitative or inductive discharge.
Claim 13
Dependent Claim
19 words
A magnetic recording medium according to claim 1, wherein said recording layer is composed of an amorphous magnetic 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) | 1993-05-14 | 1993-11-13 | 1994-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-14 | 1997-11-13 | 1998-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-14 | 2001-11-13 | 2002-05-15 | $7700.00 | Window Closed / Lapsed |