Patent US5082709A successfully refreshed from Google Patents.
US5082709A
Expired / Lapsed
US
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Thin film-type magnetic disk
Assignee: Panasonic Holdings Corp
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Filing: 1990-02-05
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Granted: 1992-01-21
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Expires: 2010-02-05
Abstract
Abstract A thin film-type magnetic disk includes a non-magnetic substrate having fine particle-like projections provided over at least the entirety of the recording areas of the magnetic disk. The fine particle-like projections are formed either on bulged portions of the substrate or are provided in the form of bands. The bulged portions and the bands extend substantially parallel to a direction of movement of a magnetic head relative to the magnetic disk. A magnetic layer, a protective layer and a lubricant layer are sequentially formed on the substrate.
Inventors
- 👤 Takashi Suzuki
- 👤 Yoshiaki Kai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:08
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/74; G11B5/82; G11B5/62; G11B5/72; G11B5/726; G11B5/7262; G11B5/7264; G11B5/7266; G11B5/73; G11B5/739; G11B5/73911; G11B5/73913; G11B5/73917; G11B5/73919; G11B5/73921; G11B5/73923; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/24; Y10T428/24355
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
134 words
A magnetic disk, comprising: a thin-film magnetic layer; a non-magnetic substrate having bulged portions which extend substantially parallel to a direction of movement of a magnetic head relative to the magnetic disk, said substrate having fine particle-like projections formed at least on said buldged portions, said projections having a height in a range of 100 to 500 Angstroms, a ratio of height to width of said projections in a direction of a plane of said substrate being greater than or equal to 0.1 and a surface density of said projections being in a range of 1 × 10 7 /mm 2 to 1 × 10 9 mm 2 , said magnetic layer being formed on said substrate; a protective layer formed on said magnetic layer; and a lubricant layer formed on said protective layer.
Claim 2
Dependent Claim
134 words
A magnetic disk, comprising: a thin-film magnetic layer; a non-magnetic substrate having bulged portions which extend substantially parallel to a direction of movement of a magnetic head relative to the magnetic disk, said substrate having fine particle-like projections formed at least on said buldged portions, said projections having a height in a range of 100 to 500 Angstroms, a ratio of height to width of said projections in a direction of a plane of said substrate being greater than or equal to 0.1 and a surface density of said projections being in a range of 1 × 10 7 /mm 2 to 1 × 10 9 mm 2 , said magnetic layer being formed on said substrate; a protective layer formed on said magnetic layer; and a lubricant layer formed on said protective layer.
Claim 3
Dependent Claim
146 words
A magnetic disk, comprising; a thin-film magnetic layer; a non-magnetic substrate having fine particle-like projections, said projections having a height in a range of 100 to 500 Angstroms, a ratio of height to width of said projections in a direction of a plane of said substrate being greater than or equal to 0.1 and being arranged to include bands thereof extending substantially parallel to a direction of movement of a magnetic head relative to the magnetic disk, a surface density of said projections at regions of said bands being in a range of 1 × 10 7 /mm 2 to 1 × 10 9 /mm 2 which is higher than a surface density of said projections at regions outside said bands, said magnetic layer being formed on said substrate; a protective layer formed on said magnetic layer; and a lubricant layer formed on said protective layer.
Claim 4
Dependent Claim
146 words
A magnetic disk, comprising; a thin-film magnetic layer; a non-magnetic substrate having fine particle-like projections, said projections having a height in a range of 100 to 500 Angstroms, a ratio of height to width of said projections in a direction of a plane of said substrate being greater than or equal to 0.1 and being arranged to include bands thereof extending substantially parallel to a direction of movement of a magnetic head relative to the magnetic disk, a surface density of said projections at regions of said bands being in a range of 1 × 10 7 /mm 2 to 1 × 10 9 /mm 2 which is higher than a surface density of said projections at regions outside said bands, said magnetic layer being formed on said substrate; a protective layer formed on said magnetic layer; and a lubricant layer formed on said protective layer.
Claim 5
Dependent Claim
124 words
A magnetic disk, comprising: a thin-film magnetic layer; a non-magnetic substrate having bands of fine particle-like projections which extend substantially parallel to a direction of movement of a magnetic head relative to the magnetic disk, said projections having a height in a range of 100 to 500 Angstroms, a ratio of height to width of said projections in a direction of a plane of said substrate being greater than or equal to 0.1 and a surface density of said projections being in a range of 1 × 10 7 /mm 2 to 1 × 10 9 mm 2 , said magnetic layer being formed on said substrate; a protective layer formed on said magnetic layer; and a lubricant layer formed on said protective layer.
Claim 6
Dependent Claim
124 words
A magnetic disk, comprising: a thin-film magnetic layer; a non-magnetic substrate having bands of fine particle-like projections which extend substantially parallel to a direction of movement of a magnetic head relative to the magnetic disk, said projections having a height in a range of 100 to 500 Angstroms, a ratio of height to width of said projections in a direction of a plane of said substrate being greater than or equal to 0.1 and a surface density of said projections being in a range of 1 × 10 7 /mm 2 to 1 × 10 9 mm 2 , said magnetic layer being formed on said substrate; a protective layer formed on said magnetic layer; and a lubricant layer formed on said protective layer.
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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) | 1995-01-20 | 1995-07-22 | 1996-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-20 | 1999-07-22 | 2000-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-20 | 2003-07-22 | 2004-01-21 | $7700.00 | Window Closed / Lapsed |