Patent US3661537A successfully refreshed from Google Patents.
US4575475A
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1984-07-10
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Granted: 1986-03-11
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Expires: 2004-07-10
Abstract
Abstract In a magnetic recording medium comprising a plastic base film and a magnetic layer formed thereon, the base film is plasma treated at frequencies in the range of 10 kHz to 200 kHz in an inorganic gas such as argon and nitrogen and preferably, in an inorganic gas containing at least 5% of oxygen.
Inventors
- 👤 Masatoshi Nakayama
- 👤 Haruyuki Morita
- 👤 Yuichi Kubota
- 👤 Keiko Tsuchiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:24
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/62; G11B5/73; G11B5/7368; G11B5/739; G11B5/73923; G11B5/73927; G11B5/73933; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
45 words
A magnetic recording medium comprising a base film and a magnetic layer formed thereon, the base film being plasma treated at a frequency in the range of 10 to 200 kilohertz in an atmosphere consisting essentially of an inorganic gas and 5-100% oxygen by volume.
Claim 2
Dependent Claim
45 words
A magnetic recording medium comprising a base film and a magnetic layer formed thereon, the base film being plasma treated at a frequency in the range of 10 to 200 kilohertz in an atmosphere consisting essentially of an inorganic gas and 5-100% oxygen by volume.
Claim 3
Dependent Claim
35 words
The magnetic recording medium according to claim 1 wherein the base film is plasma treated at a frequency in the range of 10 to 200 kilohertz in an atmosphere comprising an inorganic gas containing oxygen.
Claim 4
Dependent Claim
25 words
The magnetic recording medium according to claim 1 or 2 wherein the inorganic gas is selected from argon, neon, helium, nitrogen, hydrogen, and mixtures thereof.
Claim 5
Dependent Claim
21 words
The magnetic recording medium according to claim 1 wherein the atmosphere comprises argon and 5 to 100% by volume of oxygen.
Claim 6
Dependent Claim
21 words
The magnetic recording medium according to claim 1 wherein the atmosphere comprises nitrogen and 5 to 100% by volume of oxygen.
Claim 7
Dependent Claim
24 words
The magnetic recording medium according to claim 1 or 2 wherein the magnetic layer is formed on the base film through an undercoat layer.
Claim 8
Dependent Claim
19 words
The magnetic recording medium according to claim 1 or 2 wherein the base film is formed of a polyester.
Claim 9
Dependent Claim
18 words
The magnetic recording medium according to claim 7 wherein the base film is formed of a polyethylene terephthalate.
Claim 10
Dependent Claim
19 words
The magnetic recording medium according to claim 1 or 2 wherein the magnetic layer is a continuous thin layer.
Claim 11
Dependent Claim
47 words
The magnetic recording medium according to claim 9 wherein the magnetic layer is formed from a magnetic metal selected from the group consisting of iron, cobalt and nickel, and mixtures thereof, by a technique selected from the group consisting of vacuum deposition, ion plating, sputtering, and electroplating.
Claim 12
Dependent Claim
29 words
The magnetic recording medium according to claim 1 or 2 wherein the magnetic layer is formed from a composition comprising a magnetic metal powder and a binder by coating.
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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) | 1989-03-10 | 1989-09-09 | 1990-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-10 | 1993-09-09 | 1994-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-10 | 1997-09-09 | 1998-03-11 | $7700.00 | Window Closed / Lapsed |