Patent US4716078A successfully refreshed from Google Patents.
US4716078A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Substrate for a magnetic disc and method manufacturing same
Assignee: Kao Corp
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Filing: 1984-08-08
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Granted: 1987-12-29
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Expires: 2004-08-08
Abstract
Abstract A substrate for magnetic discs, which are to be used as external storage in data processors, is formed from glass-like carbon materials by themselves or contained in a thermosetting resin matrix. The glass-like carbon materials have excellent thermal resistance, can be finished to a mirror-like surface, and have less surface defects than aluminum substrates. Magnetic materials can be adhered directly onto the surface of such substrates shaped in the form of a disc. The resulting disc has good hardness, is resistant to elevated temperatures, is less likely to deform, and is low in cost.
Inventors
- 👤 Nobuyuki Kishine
- 👤 Tetsuya Imamura
- 👤 Michihide Yamauchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:33
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/62; G11B5/73; G11B5/739; G11B5/73923; G11B5/73925; G11B5/74; G11B5/82; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/30
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
38 words
A thermal-resistant magnetic memory storage disc comprising: a disc of a non-magnetic, molded, glass-like carbon substrate having a flat, smooth, mirror-like surface, and a continuous, thin film of magnetic material deposited on the smooth surface of said substrate.
Claim 2
Dependent Claim
38 words
A thermal-resistant magnetic memory storage disc comprising: a disc of a non-magnetic, molded, glass-like carbon substrate having a flat, smooth, mirror-like surface, and a continuous, thin film of magnetic material deposited on the smooth surface of said substrate.
Claim 3
Dependent Claim
35 words
The magnetic memory storage disc of claim 1 in which the substrate is a composite material comprising at least 40 volume percent glass-like carbon and the balance consisting essentially of at least one thermosetting resin.
Claim 4
Dependent Claim
17 words
The magnetic memory storage disc of claim 1 capable of withstanding temperatures of at least 350° C.
Claim 5
Dependent Claim
21 words
The magnetic memory storage disc of claim 1 in which the glass-like carbon in the substrate includes a carbonized thermosetting resin.
Claim 6
Dependent Claim
22 words
The magnetic memory storage disc of claim 1 in which the glass-like carbon in the substrate includes a carbonized, amorphous thermoplastic resin.
Claim 7
Dependent Claim
20 words
The magnetic memory storage disc of claim 2 in which the composite forming the substrate also contains carbon particle fillers.
Claim 8
Dependent Claim
30 words
A magnetic disc substrate molded from a hard, glass-like carbon and having at least one smooth, flat, mirror-like surface; said substrate capable of withstanding temperatures in excess of 350° C.
Claim 9
Dependent Claim
30 words
A magnetic disc substrate molded from a hard, glass-like carbon and having at least one smooth, flat, mirror-like surface; said substrate capable of withstanding temperatures in excess of 350° C.
Claim 10
Dependent Claim
22 words
A magnetic disc substrate molded from a composite containing at least 40 volume percent glass-like carbon particles in a thermosetting resin matrix.
Claim 11
Dependent Claim
22 words
A magnetic disc substrate molded from a composite containing at least 40 volume percent glass-like carbon particles in a thermosetting resin matrix.
Claim 12
Dependent Claim
13 words
The magnetic disc substrate of claim 8 which additionally contains carbon particle fillers.
Claim 13
Dependent Claim
22 words
The magnetic memory storage disc according to claim 1 wherein said film is deposited on said substrate by a reaction sputtering method.
Claim 14
Dependent Claim
18 words
The magnetic memory storage disc according to claim 10 wherein said film is about 1 μm in thickness.
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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) | 1990-12-28 | 1991-06-29 | 1991-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-28 | 1995-06-29 | 1995-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-28 | 1999-06-29 | 1999-12-29 | $7700.00 | Window Closed / Lapsed |