Patent US4988535A successfully refreshed from Google Patents.
US4988535A
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1988-09-12
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Granted: 1991-01-29
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Expires: 2008-09-12
Abstract
Abstract A magnetic recording medium comprises a non-magnetic substrate and a magnetic film which is formed on the non-magnetic substrate and the major component of which is iron nitride-oxide.
Inventors
- 👤 Yoshihiro Arai
- 👤 Tadashi Yasunaga
- 👤 Ryuji Shirahata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:47
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/658; G11B5/84; G11B5/851; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
96 words
A method of forming a non-binder type magnetic recording medium comprising the steps of providing a non-magnetic substrate; and depositing on the non-magnetic substrate a magnetic film layer by oblique incidence deposition where the magnetic film layer is, during its formation, exposed to oxygen gas and ionized nitrogen; whereby a major component of the magnetic film layer is iron nitride-oxide which extends from the upper surface of the magnetic film layer to the non-magnetic substrate, and said magnetic film layer is formed of a material having a composition represented by formula Fe.sub.1-y N.sub.x O.sub.y wherein 0.25<x+y<0.60.
Claim 2
Independent Claim
96 words
A method of forming a non-binder type magnetic recording medium comprising the steps of providing a non-magnetic substrate; and depositing on the non-magnetic substrate a magnetic film layer by oblique incidence deposition where the magnetic film layer is, during its formation, exposed to oxygen gas and ionized nitrogen; whereby a major component of the magnetic film layer is iron nitride-oxide which extends from the upper surface of the magnetic film layer to the non-magnetic substrate, and said magnetic film layer is formed of a material having a composition represented by formula Fe.sub.1-y N.sub.x O.sub.y wherein 0.25<x+y<0.60.
Claim 3
Dependent Claim
12 words
A method as in claim 1 where x is larger than y.
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) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |