Patent US5202810A successfully refreshed from Google Patents.
US5202810A
Expired / Lapsed
US
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Magnetic disk having an improved surface configuration
Assignee: HGST Japan Ltd
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Filing: 1990-04-24
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Granted: 1993-04-13
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Expires: 2010-04-24
Abstract
Abstract A magnetic disk includes a non-magnetic substrate with a surface processed layer having fine irregularities formed at least on a main surface thereof, and at least thin film magnetic film and a protective film formed in that order on the non-magnetic substrate in such a manner that the fine irregularities are duplicated thereof. The surface of the surface processed layer of the non-magnetic substrate has protrusions whose surfaces are made flat and a configuration which exhibits a three-dimensional bearing curve in which the bearing ratio at a section taken at a depth from the top of the surface which corresponds to the portion of the top portion deformed by the head load during the contact start-stops drive is between 0.1% and 10%. The protrusions formed on the surface processed layer have a height ranging from several nm to several tens of nm. The bearing ratio is a value obtained at a depth of 5 to 10 nm from the top of the protrusions.
Inventors
- 👤 Takao Nakamura
- 👤 Nobuya Sekiyama
- 👤 Masaki Ohura
- 👤 Yoshiki Kato
- 👤 Noriaki Okamoto
- 👤 Masami Masuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 04:42
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/8404; G11B5/74; G11B5/82; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
118 words
A magnetic disk comprising a non-magnetic substrate with a surface processed layer having fine irregularities formed at least on a main surface thereof, said surface processed layer of said non-magnetic substrate having protrusions whose surfaces are essentially made level, and having a surface configuration, which exhibits a three-dimensional bearing curve, and has a bearing ratio of between 0.1% and 10% at a depth from a top of the protrusions which corresponds to a portion of the surface processed layer deformed by a head load during contact start-stop operation, and a thin film magnetic layer and a protecting layer are formed in that order on said non-magnetic substrate in such a manner that said fine irregularities are duplicated thereon.
Claim 2
Dependent Claim
118 words
A magnetic disk comprising a non-magnetic substrate with a surface processed layer having fine irregularities formed at least on a main surface thereof, said surface processed layer of said non-magnetic substrate having protrusions whose surfaces are essentially made level, and having a surface configuration, which exhibits a three-dimensional bearing curve, and has a bearing ratio of between 0.1% and 10% at a depth from a top of the protrusions which corresponds to a portion of the surface processed layer deformed by a head load during contact start-stop operation, and a thin film magnetic layer and a protecting layer are formed in that order on said non-magnetic substrate in such a manner that said fine irregularities are duplicated thereon.
Claim 3
Dependent Claim
38 words
A magnetic disk according to claim 1, wherein said non-magnetic surface processed layer has a surface configuration which exhibits a three-dimensional bearing curve in which a portion of the curve which represents a surface layer thereof is flat.
Claim 4
Dependent Claim
88 words
A magnetic disk according to claim 1, wherein said surface processed layer of said non-magnetic metal substrate has a surface characteristic in which a micro groove having a depth of at least 100 nm is present within a length thereof corresponding to the width of a head slider sliding surface and in which a symmetry of a sectional curve thereof is equal to or smaller than a negative value -0.7, wherein the negative value represents that the sectional curve has a larger depth component than a protrusions component.
Claim 5
Dependent Claim
34 words
A magnetic disk according to claim 1, wherein said irregularities on said surface processed layer comprise regular grooves and protrusions formed on a recording surface of said magnetic disk in a circumferential direction thereof.
Claim 6
Dependent Claim
20 words
A magnetic disk according to claim 4, wherein said regular grooves and protrusions are formed by a plastic working technique.
Claim 7
Dependent Claim
16 words
A magnetic disk according to claim 4, wherein said regular protrusions have a polished top portion.
Claim 8
Dependent Claim
28 words
A magnetic disk set forth in claim 4, wherein said substrate is used so as to make a recording surface transferred by using a duplicate of said substrate.
Claim 9
Dependent Claim
51 words
A magnetic disk according to claim 4, wherein said grooves and said protrusions are formed by means of a cylindrical, drum-like, spherical or conical plastic working tool which is rotatable about a central axis thereof and which has a surface on which micro grooves are formed in a circumferential direction thereof.
Claim 10
Dependent Claim
38 words
A magnetic disk according to claim 1, wherein a non-magnetic intermediate film and a magnetic medium film are coated on the surface of said substrate, and wherein micro grooves and protrusions are formed on said magnetic medium film.
Claim 11
Dependent Claim
124 words
A magnetic disk comprising a non-magnetic substrate with a surface processed layer having fine irregularities formed at least on a main surface thereof, said surface processed layer of said non-magnetic metal substrate having protrusions whose height ranges from several nanometers to several tens of nanometers and whose surface characteristics are essentially made level, and having a surface configuration which exhibits a three-dimensional bearing curve, and has a bearing ratio of between 0.1% and 10% at a section taken at a depth of 5 to 10 nm from a top of the protrusions, and at least a thin film magnetic layer and a protecting layer are formed in that order on said non-magnetic substrate in such a manner that said fine irregularities are duplicated thereon.
Claim 12
Dependent Claim
124 words
A magnetic disk comprising a non-magnetic substrate with a surface processed layer having fine irregularities formed at least on a main surface thereof, said surface processed layer of said non-magnetic metal substrate having protrusions whose height ranges from several nanometers to several tens of nanometers and whose surface characteristics are essentially made level, and having a surface configuration which exhibits a three-dimensional bearing curve, and has a bearing ratio of between 0.1% and 10% at a section taken at a depth of 5 to 10 nm from a top of the protrusions, and at least a thin film magnetic layer and a protecting layer are formed in that order on said non-magnetic substrate in such a manner that said fine irregularities are duplicated thereon.
Claim 13
Dependent Claim
38 words
A magnetic disk according to claim 10, wherein said non-magnetic surface processed layer has a surface configuration which exhibits a three-dimensional bearing curve in which a portion of the curve which represents a surface layer thereof is flat.
Claim 14
Dependent Claim
89 words
A magnetic disk according to claim 10, wherein said surface processed layer of said non-magnetic metal substrate has a surface character in which a micro groove having a depth of at least 100 nm is present within a length thereof corresponding to the width of a head slider sliding surface and in which the symmetry of a sectional curve thereof Rsk is equal to or smaller than a negative value -0.7, wherein the negative value represents that the sectional curve has a larger depth component than a protrusion component.
Claim 15
Dependent Claim
34 words
A magnetic disk according to claim 10, wherein said irregularities on said surface processed layer comprise regular grooves and protrusions formed on a recording surface of said magnetic disk in a circumferential direction thereof.
Claim 16
Dependent Claim
38 words
A magnetic disk according to claim 10, wherein a non-magnetic intermediate film and a magnetic medium film are coated on the surface of said substrate, and wherein micro grooves and protrusions are formed on said magnetic medium 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) | 1996-04-12 | 1996-10-12 | 1997-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-12 | 2000-10-12 | 2001-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-12 | 2004-10-12 | 2005-04-13 | $7700.00 | Window Closed / Lapsed |