Patent US3947993A successfully refreshed from Google Patents.
Patent EP0369784A2 successfully refreshed from Google Patents.
EP0369784A2
Expired / Lapsed
EP
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Magnetic disk and production method thereof
Assignee: Toshiba Corp
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Filing: 1989-11-16
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Granted: —
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Expires: 2009-11-16
Abstract
Abstract The present magnetic disk comprises a substrate layer which has a plurality of grooves formed almost concentrically in the circumferential direction of the magnetic disk so that the angle between the disk tangent and a groove increases as the groove approaches the disk periphery, and a magnetic recording layer formed on the substrate layer. In the central area of the disk, good magnetic force resistance Hc, coercive squareness ratio, and recording density can be obtained and in the peripheral area, the OWM characteristics can be improved.
Inventors
- 👤 Koutaro C/O Patent Division Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 11:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/8404; G11B5/012; G11B5/02; G11B5/09; G11B5/74; G11B5/82
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
52 words
A magnetic disk comprising: a substrate which has a plurality of grooves formed almost concentrically in the circumferential direction of said magnetic disk so that the angle between the disk tangent and a groove increases as the groove approaches the disk periphery, and a magnetic recording layer formed on said substrate layer.
Claim 2
Dependent Claim
52 words
A magnetic disk comprising: a substrate which has a plurality of grooves formed almost concentrically in the circumferential direction of said magnetic disk so that the angle between the disk tangent and a groove increases as the groove approaches the disk periphery, and a magnetic recording layer formed on said substrate layer.
Claim 3
Dependent Claim
33 words
A magnetic disk according to Claim 1, wherein said angle is approximately 0 to 5 degrees in the innermost area of said disk and approximately 5 to 30 degrees in the outermost area.
Claim 4
Dependent Claim
53 words
A production method of magnetic disks comprising steps of forming a plurality of grooves almost concentrically in a circular substrate of a magnetic disk so that the angle between the disk tangent and a groove increases as the groove approaches the disk periphery, and forming a magnetic recording layer on said substrate layer.
Claim 5
Dependent Claim
53 words
A production method of magnetic disks comprising steps of forming a plurality of grooves almost concentrically in a circular substrate of a magnetic disk so that the angle between the disk tangent and a groove increases as the groove approaches the disk periphery, and forming a magnetic recording layer on said substrate layer.
Claim 6
Dependent Claim
33 words
A production method according to Claim 3, wherein said angle is approximately 0 to 5 degrees in the innermost area of said disk and approximately 5 to 30 degrees in the outermost area.
Claim 7
Dependent Claim
22 words
A production method according to Claim 3, wherein said grooves are formed by rotating said substrate and spraying hard powder on it.
Claim 8
Dependent Claim
32 words
A production method according to Claim 3, wherein said grooves are formed by rotating said substrate and moving an abrasive tape in the radial direction while keeping in contact with said layer.
References Cited (Backward Citations)
No citation records indexed.
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