US4717622A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording media
Assignee: Panasonic Holdings Corp
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Filing: 1986-03-11
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Granted: 1988-01-05
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Expires: 2006-03-11
Abstract
Abstract A magnetic recording medium has a protective layer made of high hardness carbon synthesized under a low-temperature and a low-pressure by blowing hydrocarbon gas plasma onto a magnetic recording layer. The resistance thereof is large, and therefore, high density magnetic recording can be realized in a magnetic recording system wherein the magnetic head contacts the magnetic recording medium. Durability of the magnetic recording medium is substantially improved.
Inventors
- 👤 Hideo Kurokawa
- 👤 Tsutomu Mitani
- 👤 Taketoshi Yonezawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:36
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/727; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/30; Y10T428/31504; Y10T428/31536
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
106 words
A magnetic recording medium, comprising: a base material made of non-magnetic material; a recording layer disposed on said base material, said recording layer being made of a ferromagnetic material; and a protective layer disposed on said recording layer; said protective layer being constituted by a diamond-like film of carbon having a Vicker's hardness of more than 2000 kg/mm 2 and a specific resistance of 10 7 Ω·cm to 10 13 Ω·cm; and said ferromagnetic material comprising an element which forms a carbide with carbon of said protective layer, in which said element is bonded to said carbon by covalent bonding or forms an intermetallic compound therewith.
Claim 2
Dependent Claim
106 words
A magnetic recording medium, comprising: a base material made of non-magnetic material; a recording layer disposed on said base material, said recording layer being made of a ferromagnetic material; and a protective layer disposed on said recording layer; said protective layer being constituted by a diamond-like film of carbon having a Vicker's hardness of more than 2000 kg/mm 2 and a specific resistance of 10 7 Ω·cm to 10 13 Ω·cm; and said ferromagnetic material comprising an element which forms a carbide with carbon of said protective layer, in which said element is bonded to said carbon by covalent bonding or forms an intermetallic compound therewith.
Claim 3
Dependent Claim
21 words
The magnetic recording medium of claim 1, wherein: said protective layer is an amorphous carbon layer consisting mainly of diamond-structure carbon.
Claim 4
Dependent Claim
15 words
The magnetic recording medium of claim 2, wherein: said protective layer also includes graphitic carbon.
Claim 5
Independent Claim
86 words
A method for making a magnetic recording medium, comprising: (a) providing a base material made of non-magnetic material; (b) successively, and in the same chamber, (i) forming on said base material a recording layer made of ferromagnetic material by one of sputtering and vapor deposition, and (ii) forming on said recording layer a protective layer of amorphous diamond by blowing a hydrocarbon gas plasma onto said recording layer while accelerating towards said recording layer ions of at least one chemical and electronic constituency in said plasma.
Claim 6
Independent Claim
86 words
A method for making a magnetic recording medium, comprising: (a) providing a base material made of non-magnetic material; (b) successively, and in the same chamber, (i) forming on said base material a recording layer made of ferromagnetic material by one of sputtering and vapor deposition, and (ii) forming on said recording layer a protective layer of amorphous diamond by blowing a hydrocarbon gas plasma onto said recording layer while accelerating towards said recording layer ions of at least one chemical and electronic constituency in said plasma.
Claim 7
Dependent Claim
39 words
The method of claim 4, wherein: said protective layer is constituted by a diamond-like film of carbon having a Vicker's hardness of more than 2000 kg/mm 2 and a specific resistance of 10 7 Ω·cm to 10 13 Ω·cm.
Claim 8
Dependent Claim
40 words
The method of claim 5, wherein: said ferromagnetic material comprises an element which forms a carbide with carbon of said protective layer, in which said element is bonded to said carbon by covalent bonding or forms an intermetallic compound therewith.
Claim 9
Dependent Claim
19 words
The method of claim 6, wherein: said protective layer is an amorphous carbon layer consisting mainly of diamond-structure carbon.
Claim 10
Dependent Claim
13 words
The method of claim 7, wherein: said protective layer also includes graphitic carbon.
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) | 1991-01-04 | 1991-07-06 | 1992-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-04 | 1995-07-06 | 1996-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-04 | 1999-07-06 | 2000-01-05 | $7700.00 | Window Closed / Lapsed |