US5082709A
Expired / Lapsed
US
⏱️ 0.0 years remaining
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 10:57
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.
References Cited (Backward Citations)
US4326229A
Cited
US4873138A
Cited
US4828899A
Cited
US4698251A
Cited
US4725470A
Cited
US4735840A
Cited
US4804590A
Cited
US4939614A
Cited
US4973496A
Cited
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 |