Patent EP0447025A1 successfully refreshed from Google Patents.
EP0447025A1
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Magnetic recording media and processes for manufacture thereof
Assignee: Seagate Technology International
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Filing: 1991-01-28
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Granted: —
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Expires: 2011-01-28
Abstract
Abstract A magnetic recording disk (16) is controllably texturized, over areas designated for contact with a data transducing head. The process includes polishing an aluminium, nickel-phosphorous substrate to a specular finish, then rotating the disk while directing a beam (46) of pulsed laser energy from a laser (44) over a limited portion of the radius, thus forming an annular head contact band (32) while leaving the remainder of the surface 48 specular. The band is formed of multiple individual laser spots, each with a central depression surrounded by a substantially circular raised rim. The depth of the depressions and height of the rims are controlled primarily by laser power and firing pulse duration. The shape of individual laser spots can be altered by varying the laser beam inclination relative to the disk surface. The smooth, rounded contours of the depressions and surrounding rims, as compared to the acicular character of mechanically textured surfaces, is a primary factor contributing to substantially increased durability of laser texturized media.
Inventors
- 👤 Rajiv Y. Ranjan
- 👤 David N. Lambeth
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 13:34
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/50; G11B23/505; G11B5/00; G11B5/48; G11B5/58; G11B5/60; G11B5/6005; G11B5/6082; G11B5/74; G11B5/82; G11B5/84; G11B5/8404; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12229; Y10T428/12236; Y10T428/12243; Y10T428/12472; Y10T428/12493; Y10T428/12736; Y10T428/1275; Y10T428/12993
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
60 words
A process for manufacturing magnetic recording media, including a plurality of layers, at least one of which is a substrate of non-magnetizable material and at least one of which is magnetizable film, characterised in that the surface of one of the layers is subjected to selective energy concentration application to roughen the surface at least in a treatment area thereof.
Claim 2
Dependent Claim
144 words
A process for manufacturing magnetic recording media, including the steps of forming a specular substrate surface (48) on a non-magnetizable substrate body, said substrate surface being substantially planar and having a nominal roughness; and depositing a magnetizable film (52) over said substrate surface as a layer substantially uniform in thickness with a recording surface, characterised by concentrating energy selectively upon a plurality of locations over a treatment area (32) on a selected one of said substrate surface and recording surface, to controllably alter the topography of the selected surface at each of the locations, adjacent locations being spaced apart from one another by a distance substantially less than the length or width of a magnetic transducing head positionable adjacent the surface of the magnetic film (52), and the roughness of said selected surface in the treatment area being at least twice said nominal roughness.
Claim 3
Dependent Claim
159 words
A process as claimed in claim 2, wherein the substrate body is a disk, characterised in that the step of concentrating energy includes: (a) rotating the disk at a controlled rotational velocity; (b) simultaneously providing pulsed laser energy at a controlled frequency corresponding to the rotational velocity to form a first ring comprised of a series of rounded depressions (56) in the substrate surface; (c) after forming the ring, displacing the laser radially relative to the disk; (d) providing pulsed laser energy at the controlled frequency while rotating the disk at the rotational velocity to form another ring comprised of another series of depressions concentric with the first ring and radially spaced apart from the first ring by a pitch corresponding to the amount of laser radial displacement; and (e) repeating steps (c) and (d) to form a selected number of concentric rings, whereby the treatment area consists of a designated region in the form of an annular band.
Claim 4
Dependent Claim
108 words
A process as claimed in claim 2 characterised in that the step of concentrating energy includes: (a) moving the substrate at a controlled velocity in the longitudinal direction; (b) simultaneously directing a beam of pulsed laser energy upon the surface at a controlled frequency to form a first row of depressions; (c) displacing the beam transversely by a selected pitch, and providing the beam of laser energy while longitudinally moving the substrate, to form a subsequent row of depressions parallel to the first row; and (d) repeating step (c) a selected number of times to form the designated region as a longitudinal band of a selected transverse width.
Claim 5
Dependent Claim
49 words
A process as claimed in claim 1, 2, 3 or 4 wherein the substrate body includes a layer (40) of a nickel-phosphorous alloy plated onto a rigid aluminium body as a layer substantially uniform in thickness, the treated substrate surface being a surface of the nickel-phosphorous alloy layer (40).
Claim 6
Dependent Claim
39 words
A process as claimed in claim 1, 2, 3, 4 or 5, including depositing a protective cover layer over said magnetizable film, said cover layer having a substantially uniform thickness and replicating the surface contours of said magnetizable film.
Claim 7
Dependent Claim
46 words
A process as claimed in any preceding claim including depositing a non-magnetizable underlayer (50) on the substrate surface prior to depositing the magnetizable film (52) over the substrate surface, the non-magnetizable underlayer having a substantially uniform thickness and replicating the surface contours of the substrate surface.
Claim 8
Dependent Claim
72 words
A magnetic recording medium comprising a non-magnetizable body with a magnetizable film deposited thereover as a layer of substantially uniform thickness, characterised in that a specular substrate surface on the body or a recording surface on the film has a treatment area with depressions formed at a plurality of locations by selective energy concentration, the roughness of the treatment area being at least twice the nominal roughness of the specular substrate surface.
Claim 9
Dependent Claim
138 words
A medium as claimed in claim 8, in which the medium is a disk including a substantially rigid, non-magnetizable substrate having a substantially planar substrate surface, said disk further including a magnetizable film deposited over said substrate surface as a layer substantially uniform in thickness, and said disk having an outer surface having a nominal surface plane; characterised in that the outer surface includes a plurality of marks, each comprising a depression extended inwardly of the nominal plane toward said substrate a distance in the range of from 12.7 to 254 nm (0.5 to 10 microinches), and a rounded rim substantially surrounding each depression and extended outwardly of the nominal surface plane by a height of at least 5.08 nm (0.2 microinches), each of the rims having a diameter in the range of from 0.1 to 5 mils.
Claim 10
Dependent Claim
75 words
A medium as claimed in claim 9, wherein the outer surface includes a first area adapted for surface engagement with a magnetic transducing head, and a second area adapted for storage of magnetic data, wherein said head during recording and reading operations is maintained in spaced apart relation to the second area by an air film generated by rotation of said disk, and wherein said depressions and rims are formed only throughout the first area.
References Cited (Backward Citations)
DE3629582A1
Cited
GB2221425A
Cited
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