US4675240A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording disk using silicon substrate
Assignee: HGST Netherlands BV
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Filing: 1984-05-23
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Granted: 1987-06-23
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Expires: 2004-05-23
Abstract
Abstract A magnetic recording disk includes a silicon substrate which is extremely flat and essentially asperity-free. A nonmagnetic underlayer is deposited on the silicon to enhance the magnetic performance of the magnetic layer which is deposited on the underlayer. A protective nonmagnetic overlayer is deposited on the magnetic layer.
Inventors
- 👤 Joel R. Weiss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:16
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; H; H01; H01F; H01F10/00; H01F10/26; H01F10/30; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12674; Y10T428/12771; Y10T428/12806; Y10T428/12812; Y10T428/12826; Y10T428/12833; Y10T428/12847; Y10T428/12854; Y10T428/12861; Y10T428/12931; Y10T428/12951; Y10T428/26; Y10T428/266; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
92 words
A rotatable magnetic recording disk comprising: a thin silicon substrate consisting essentially of single crystal silicon, having at least one flat surface that is essentially asperity-free; a magnetic layer on at least one such flat surface of said substrate; a nonmagnetic underlayer interposed between and in contact with each magnetic layer and the substrate to enhance adhesion of the magnetic layer to said flat surface and enhance magnetic performance of the magnetic layer; and said silicon substrate constituting the sole support for said layers and any others constituting said magnetic recording disk.
Claim 2
Dependent Claim
92 words
A rotatable magnetic recording disk comprising: a thin silicon substrate consisting essentially of single crystal silicon, having at least one flat surface that is essentially asperity-free; a magnetic layer on at least one such flat surface of said substrate; a nonmagnetic underlayer interposed between and in contact with each magnetic layer and the substrate to enhance adhesion of the magnetic layer to said flat surface and enhance magnetic performance of the magnetic layer; and said silicon substrate constituting the sole support for said layers and any others constituting said magnetic recording disk.
Claim 3
Dependent Claim
20 words
A magnetic recording disk in accordance with claim 1, including a hard nonmagnetic protective overcoat layer covering each magnetic layer.
Claim 4
Dependent Claim
20 words
A magnetic recording disk according to claim 1, wherein said silicon substrate haas a thickness not exceeding about 0.032 inch.
Claim 5
Dependent Claim
14 words
A magnetic recording disk according to claim 1, wherein said nonmagnetic underlayer comprises Cr.
Claim 6
Dependent Claim
101 words
A rotatable magnetic recording disk consisting of: a thin silicon substrate consisting essentially of single crystal silicon, having at least one flat surface that is essentially smooth; a magnetic layer applied to at least one such flat surface; a nonmagnetic Cr-containing underlayer interposed between and in contact with each magnetic layer and the substrate to enhance adhesion of said magnetic layer to such associated flat surface and enhance magnetic performance of the associated magnetic layer; a hard nonmagnetic protective overcoat layer covering each magnetic layer; and said silicon substrate constituting the sole support for said layers constituting said magnetic recording disk.
Claim 7
Dependent Claim
101 words
A rotatable magnetic recording disk consisting of: a thin silicon substrate consisting essentially of single crystal silicon, having at least one flat surface that is essentially smooth; a magnetic layer applied to at least one such flat surface; a nonmagnetic Cr-containing underlayer interposed between and in contact with each magnetic layer and the substrate to enhance adhesion of said magnetic layer to such associated flat surface and enhance magnetic performance of the associated magnetic layer; a hard nonmagnetic protective overcoat layer covering each magnetic layer; and said silicon substrate constituting the sole support for said layers constituting said magnetic recording disk.
Claim 8
Dependent Claim
20 words
A magnetic recording disk according to claim 5, wherein said silicon substrate has a thickness not exceeding about 0.032 inch.
Claim 9
Dependent Claim
26 words
A magnetic recording disk in accordance with claim 5, in which said nonmagnetic underlayer is sputtered Cr and in which said magnetic layer is sputtered Fe:Co:Cr.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-22 | 1990-12-22 | 1991-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-22 | 1994-12-22 | 1995-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-22 | 1998-12-22 | 1999-06-23 | $7700.00 | Window Closed / Lapsed |