US4724156A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1986-09-02
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Granted: 1988-02-09
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Expires: 2006-09-02
Abstract
Abstract In manufacturing a magnetic recording medium, a flow of iron vapor is formed in a nitrogen atmosphere and iron vapor particles in the flow of iron vapor are deposited on a non-magnetic substrate together with nitrogen particles to form an iron nitride film thereon. Before deposition on the non-magnetic substrate, the nitrogen particles are ionized by an ion beam generating means and the iron vapor particles are ionized by a high-frequency discharge.
Inventors
- 👤 Yoshihiro Arai
- 👤 Tadashi Yasunaga
- 👤 Ryuji Shirahata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:43
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/85; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70605; G11B5/70615
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
78 words
A method of manufacturing a magnetic recording medium in which a magnetic iron nitride film is deposited on a non-magentic substrate, comprising the steps of: (a) generating an iron vapor, (b) ionizing nitrogen by an ion beam to form a nitrogen ion beam, (c) ionizing said iron vapor by high frequency discharge to form an iron ion beam which intersects said nitrogen ion beam of (b) and, (d) thus forming said iron nitride film on said non-magnetic substrate.
Claim 2
Independent Claim
78 words
A method of manufacturing a magnetic recording medium in which a magnetic iron nitride film is deposited on a non-magentic substrate, comprising the steps of: (a) generating an iron vapor, (b) ionizing nitrogen by an ion beam to form a nitrogen ion beam, (c) ionizing said iron vapor by high frequency discharge to form an iron ion beam which intersects said nitrogen ion beam of (b) and, (d) thus forming said iron nitride film on said non-magnetic substrate.
References Cited (Backward Citations)
US4557944A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-08 | 1991-08-10 | 1992-02-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-08 | 1995-08-10 | 1996-02-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-08 | 1999-08-10 | 2000-02-09 | $7700.00 | Window Closed / Lapsed |