US5413873A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium having a glass or amorphous carbon substrate, vanadium or molybdenum precoat layer, chromium primer layer and cobalt magnetic layer
Assignee: JVCKenwood Corp
•
Filing: 1993-07-26
•
Granted: 1995-05-09
•
Expires: 2013-07-26
Abstract
Abstract A magnetic recording medium comprising: a precoat layer, having a thickness of 30 to 14000 ANGSTROM , consisting of any of V (vanadium), Mo (molybdenum), NiP (nickel-phosphorus), C (carbon), Zr (zirconium) or Al (aluminum) formed on a non-magnetic, mirror-surface substrate 1, and a Cr (chromium) layer as a primer layer 3 and a Co (cobalt) alloy layer as a magnetic layer 4 laminated in order on the precoat layer 2.
Inventors
- 👤 Makoto Mizukami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:54
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73911; G11B5/73921; G11B5/7368; G11B5/7369; G11B5/73923; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/12493; Y10T428/12771; Y10T428/12806; Y10T428/12819; Y10T428/12826; Y10T428/12833; Y10T428/12847; Y10T428/12854; Y10T428/12993; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/24975; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/30; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
107 words
A magnetic recording medium comprising: a non-magnetic, mirror-surface substrate selected from the group consisting of glass and amorphous carbon, said substrate having a mirror surface which is not texture-treated; a precoat layer consisting of any of V and Mo formed on the non-magnetic mirror-surface substrate, said precoat layer having a thickness of about 30-4,000 Å; a primer layer laminated on the precoat layer, said primer layer being Cr and having a thickness of about 60-4000 Å; and a magnetic layer laminated on the primer layer, said magnetic layer being selected from the group consisting of CoCrTa, CoCrPt and CoCrTaPt and having a thickness of about 100-2000 Å.
Claim 2
Dependent Claim
107 words
A magnetic recording medium comprising: a non-magnetic, mirror-surface substrate selected from the group consisting of glass and amorphous carbon, said substrate having a mirror surface which is not texture-treated; a precoat layer consisting of any of V and Mo formed on the non-magnetic mirror-surface substrate, said precoat layer having a thickness of about 30-4,000 Å; a primer layer laminated on the precoat layer, said primer layer being Cr and having a thickness of about 60-4000 Å; and a magnetic layer laminated on the primer layer, said magnetic layer being selected from the group consisting of CoCrTa, CoCrPt and CoCrTaPt and having a thickness of about 100-2000 Å.
Claim 3
Dependent Claim
19 words
A magnetic recording medium according to claim 1 wherein the precoat layer is at least more than one layer.
Claim 4
Dependent Claim
21 words
A magnetic recording medium according to claim 1 further comprising a carbon layer and a lubricant layer on the magnetic layer.
References Cited (Backward Citations)
US3243269A
Cited
US4552820A
Cited
JPS61188732A
Cited
JPS61222021A
Cited
US4816311A
Cited
JPS61243928A
Cited
JPS62205517A
Cited
US4725840A
Cited
US4833020A
Cited
US4876117A
Cited
US5024903A
Cited
US5122423A
Cited
EP0399747A2
Cited
US5242728A
Cited
US5314745A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-05-08 | 1998-11-07 | 1999-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-05-08 | 2002-11-07 | 2003-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-05-08 | 2006-11-07 | 2007-05-09 | $7700.00 | Window Closed / Lapsed |