US4911967A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Substrate for magnetic disk memory and production process
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1988-02-03
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Granted: 1990-03-27
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Expires: 2008-02-03
Abstract
Abstract Substrate for magnetic disk memory and production process. The substrate comprises an aluminium wafer (10) and two plastic sheets (39,41) pressed hot against the wafer. The outer faces (38,40) have a good flatness or smoothness, as a result of the surface state of the pressing plates. Application to the production of substrates used in the manufacture of disks for magnetic recording purposes.
Inventors
- 👤 Jean-Pierre Lazzari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:27
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/74; G11B5/82; G11B5/62; G11B5/73; G11B5/739; G11B5/73911; G11B5/73917; G11B5/73919; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24479; Y10T428/2457; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
62 words
A magnetic disk memory comprising a substrate having at least one major surface and a magnetic layer deposited on said major surface, said substrate comprising an aluminum wafer covered on said major surface by an organic plastic sheet hot pressed onto the wafer, and offering a smooth outer surface on which said magnetic layer is formed, said sheet, after pressing, bearing grooves.
Claim 2
Dependent Claim
62 words
A magnetic disk memory comprising a substrate having at least one major surface and a magnetic layer deposited on said major surface, said substrate comprising an aluminum wafer covered on said major surface by an organic plastic sheet hot pressed onto the wafer, and offering a smooth outer surface on which said magnetic layer is formed, said sheet, after pressing, bearing grooves.
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) | 1993-03-26 | 1993-09-25 | 1994-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-26 | 1997-09-25 | 1998-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-26 | 2001-09-25 | 2002-03-27 | $7700.00 | Window Closed / Lapsed |