US4399013A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing a magnetic recording medium
Assignee: Panasonic Holdings Corp
•
Filing: 1981-03-04
•
Granted: 1983-08-16
•
Expires: 2001-03-04
Abstract
Abstract There is provided a method of producing a magnetic recording medium having a magnetic layer composed mostly of Co and Cr. The method is characterized by vacuum vapor deposition of components which are to form the magnetic layer under conditions where atoms of the evaporated components are in the discharge state.
Inventors
- 👤 Ryuji Sugita
- 👤 Toshiaki Kunieda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/656; G11B5/84; G11B5/851; H; H01; H01F; H01F41/00; H01F41/14; H01F41/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
100 words
A method of producing a perpendicular magnetic recording medium, including a step of forming a magnetic layer as a thin film composed predominantly of cobalt and chromium on a substrate, wherein said thin film is formed by vacuum vapor deposition under conditions which comprise: producing a vapor composed predominantly of cobalt and chromium from an evaporation source, causing electrons to be produced in proximity to said evaporation source and causing these electrons to reach the substrate surface in an amount sufficient to cause the atoms of vaporized film-forming material at or near the substrate to be in the discharge state.
Claim 2
Independent Claim
100 words
A method of producing a perpendicular magnetic recording medium, including a step of forming a magnetic layer as a thin film composed predominantly of cobalt and chromium on a substrate, wherein said thin film is formed by vacuum vapor deposition under conditions which comprise: producing a vapor composed predominantly of cobalt and chromium from an evaporation source, causing electrons to be produced in proximity to said evaporation source and causing these electrons to reach the substrate surface in an amount sufficient to cause the atoms of vaporized film-forming material at or near the substrate to be in the discharge state.
Claim 3
Dependent Claim
69 words
The method of producing a magnetic recording medium as claimed in claim 1, wherein at least one evaporation source for at least one component of said film-forming material is an evaporation source associated with an electron gun and the electric power supplied to said electron gun during the formation of said magnetic layer is sufficiently large to cause the atoms of vaporized material to be in the discharge state.
Claim 4
Dependent Claim
33 words
The method for producing a magnetic recording medium as claim in claim 2, wherein an evaporation source is used which is insulated from the environment except for action of said associated electron gun.
Claim 5
Dependent Claim
66 words
The method of producing a magnetic recording medium as claimed in claim 1, wherein at least one evaporation source for at least one component of said film-forming material is an evaporation source associated with an electron gun and said vacuum vapor deposition is carried out with said substrate or the vicinity of said substrate being maintained at a positive potential with respect to said evaporation source.
Claim 6
Dependent Claim
72 words
The method of producing a magnetic recording medium as claimed in claim 1, wherein said vacuum vapor deposition is carried out by applying a high frequency voltage to a high frequency electrode positioned between said substrate and an evaporation source for film-forming material to thereby ionize atoms of said film-forming material, with said substrate or the vicinity of said substrate being maintained at a positive potential with respect to said evaporation source.
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) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |