US4548871A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1983-12-16
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Granted: 1985-10-22
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Expires: 2003-12-16
Abstract
Abstract A magnetic recording medium which comprises a magnetic layer formed on a substrate and comprising Co, or Co and one to three elements selected from the group consisting of Ni, Cr and O, said magnetic layer comprising sequentially from the substrate side, a first portion composed of crystal particles which are not inclined relative to the normal line of the principal plane of the substrate, a second portion composed of columnar crystal particles which are inclined relative to the normal line of the principal plane of the substrate, and a third portion composed of crystal particles which are not inclined relative to the normal line of the principal plane of the substrate.
Inventors
- 👤 Kouji Kobayashi
- 👤 Kiyoshi Noguchi
- 👤 Suguru Takayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:51
CPC Classifications
C; C23; C23C; C23C14/00; C23C14/22; C23C14/225; C23C14/226; G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/658; G11B5/68; G11B5/70; G11B5/716; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/1234; Y10T428/12465; Y10T428/12493; Y10T428/12639; Y10T428/12646; Y10T428/1266; Y10T428/12771; Y10T428/12861; Y10T428/12931
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
112 words
A magnetic recording medium which comprises a magnetic layer formed on a substrate and comprising Co, or Co and one to three elements selected from the group consisting of Ni, Cr and O, said magnetic layer comprising sequentially from the substrate side, a first portion composed of crystal particles which are not inclined relative to the normal line of the principal plane of the substrate, a second portion composed of columnar crystal particles which are inclined relative to the normal line of the principal plane of the substrate, and a third portion composed of crystal particles which are not inclined relative to the normal line of the principal plane of the substrate.
Claim 2
Dependent Claim
112 words
A magnetic recording medium which comprises a magnetic layer formed on a substrate and comprising Co, or Co and one to three elements selected from the group consisting of Ni, Cr and O, said magnetic layer comprising sequentially from the substrate side, a first portion composed of crystal particles which are not inclined relative to the normal line of the principal plane of the substrate, a second portion composed of columnar crystal particles which are inclined relative to the normal line of the principal plane of the substrate, and a third portion composed of crystal particles which are not inclined relative to the normal line of the principal plane of the substrate.
Claim 3
Dependent Claim
21 words
The magnetic recording medium according to claim 1, wherein the first portion has a thickness of from 50 to 2,000 A.
Claim 4
Dependent Claim
21 words
The magnetic recording medium according to claim 1, wherein the second portion has a thickness of from 500 to 5,000 A.
Claim 5
Dependent Claim
21 words
The magnetic recording medium according to claim 1, wherein the third portion has a thickness of from 50 to 500 A.
Claim 6
Dependent Claim
21 words
The magnetic recording medium according to claim 1 wherein the magnetic layer has a thickness of from 600 to 5,000 A.
Claim 7
Dependent Claim
24 words
The magnetic recording medium according to claim 1, wherein the magnetic layer contains Ni, and the weight ratio of Co/Ni is at least 1.5.
Claim 8
Dependent Claim
27 words
The magnetic recording medium according to claim 1, wherein the magnetic layer contains Cr, and the weight ratio of Cr/(Co or Co+Ni) is from 0.001 to 0.1.
Claim 9
Dependent Claim
26 words
The magnetic recording medium according to claim 1, wherein the magnetic layer contains O, and the weight ratio of O/(Co or Co+Ni) is at most 0.2.
References Cited (Backward Citations)
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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) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |