US5232791A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium having a carbon rich coating
Assignee: 3M Co
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Filing: 1991-12-23
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Granted: 1993-08-03
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Expires: 2011-12-23
Abstract
Abstract The present invention provides a magnetic recording medium that includes a polymeric flexible substrate and a magnetic layer coating thereon, with a binderless carbon rich layer adhered to the magnetic layer. The present invention also provides a process for the plasma deposition of the carbon rich coating onto a magnetic medium comprising the steps of: a. providing a magnetic medium in a vacuum chamber; b. generating carbon rich plasma in the vacuum chamber by injecting a plasma gas suitable to provide a carbon rich coating into an elongated hollow cathode; and providing a sufficient voltage to create and maintain plasma; and maintaining a vacuum in the vacuum chamber sufficient for the plasma; and c. exposing the magnetic medium to the plasma while the magnetic medium is influenced by a radio frequency bias electrode to accelerate the plasma towards the magnetic medium and deposit the carbon rich coating on the magnetic medium.
Inventors
- 👤 Gunter A. Kohler
- 👤 Richard W. Duerst
- 👤 Daniel P. Stubbs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:17
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/22; C23C16/26; C23C16/44; C23C16/50; C23C16/513; G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/725; G11B5/7253; G11B5/7257; G11B5/726; G11B5/7262; G11B5/7264; G11B5/7266; G11B5/727; G11B5/84; G11B5/8408; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
95 words
A magnetic recording medium comprising a substrate and a magnetic layer, comprising magnetizable particles in a binder, coated thereon, which is characterized by: 1) a carbon rich layer comprising at least 50 at . % of carbon that does not include a binder, located on the side of said magnetic layer opposite the substrate, said carbon rich layer being characterized by: (a) a thickness of 10-100 nanometers, and (b) a surface resistivity of about 10 8 -10 12 ohms/square; and 2) said substrate being polymeric and having a bending stiffness, D, less than about 36.
Claim 2
Dependent Claim
95 words
A magnetic recording medium comprising a substrate and a magnetic layer, comprising magnetizable particles in a binder, coated thereon, which is characterized by: 1) a carbon rich layer comprising at least 50 at . % of carbon that does not include a binder, located on the side of said magnetic layer opposite the substrate, said carbon rich layer being characterized by: (a) a thickness of 10-100 nanometers, and (b) a surface resistivity of about 10 8 -10 12 ohms/square; and 2) said substrate being polymeric and having a bending stiffness, D, less than about 36.
Claim 3
Dependent Claim
20 words
The magnetic recording medium of claim 1 wherein said carbon rich layer comprises about 50 to 95 atom percent carbon.
Claim 4
Dependent Claim
20 words
The magnetic recording medium of claim 2 wherein said carbon rich layer comprises about 0.1% to 20 atom percent nitrogen.
Claim 5
Dependent Claim
20 words
The magnetic recording medium of claim 2 wherein said carbon rich layer is substantially impervious to water vapor and oxygen.
Claim 6
Dependent Claim
17 words
The magnetic recording medium of claim 2 which further comprises fluorocarbon lubricant on the carbon rich layer.
Claim 7
Dependent Claim
27 words
The magnetic recording medium of claim 3 wherein said carbon rich layer further includes 0.1 to 20 atom percent oxygen and 0.1 to 40 atom percent hydrogen.
Claim 8
Dependent Claim
97 words
A magnetic recording medium comprising a substrate and a magnetic layer, comprising magnetizable particles in a binder, coated thereon, which is characterized by: 1) a carbon rich layer comprising at least 50 at . % of carbon, that does not include a binder, located on the side of the magnetic layer opposite the substrate, said carbon rich layer being characterized by: (a) a thickness of 10-100 nanometers, and (b) a water vapor transmission rate of less than 2 g/m 2 -day; and 2) said substrate being polymeric and having a bending stiffness, D, less than about 36.
Claim 9
Dependent Claim
97 words
A magnetic recording medium comprising a substrate and a magnetic layer, comprising magnetizable particles in a binder, coated thereon, which is characterized by: 1) a carbon rich layer comprising at least 50 at . % of carbon, that does not include a binder, located on the side of the magnetic layer opposite the substrate, said carbon rich layer being characterized by: (a) a thickness of 10-100 nanometers, and (b) a water vapor transmission rate of less than 2 g/m 2 -day; and 2) said substrate being polymeric and having a bending stiffness, D, less than about 36.
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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) | 1996-08-02 | 1997-02-01 | 1997-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-02 | 2001-02-01 | 2001-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-02 | 2005-02-01 | 2005-08-03 | $7700.00 | Window Closed / Lapsed |