US5108781A
Expired / Lapsed
US
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Process for manufacturing selectively textured magnetic recording media
Assignee: Magnetic Peripherals Inc
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Filing: 1991-03-26
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Granted: 1992-04-28
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Expires: 2011-03-26
Abstract
Abstract Magnetic recording media are controllably textured, particularly over areas designated for contact with data transducing heads. In connection with rigid media, the process includes polishing an aluminum nickel-phosphorous substrate to a specular finish, then rotating the disc while directing pulsed laser energy over a limited portion of the radius, thus forming an annular head contact band while leaving the remainder of the surface specular. The band is formed of multiple individual laser spots, each with a center 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 disc surface. On a larger scale, the frequency of firing the laser in combination with disc rotational speed controls the pattern or arrangement of laser spots. 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 textured media.
Inventors
- 👤 Rajiv Y. Ranjan
- 👤 David N. Lambeth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:21
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/50; G11B23/505; G11B5/00; G11B5/48; G11B5/58; G11B5/60; G11B5/6005; G11B5/74; G11B5/82; G11B5/84; G11B5/8404
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
157 words
A process for manufacturing magnetic media operated in conjunction with magnetic transducing heads for the recording and reading of magnetic data, including the steps of: forming a specular substrate surface on a non-magnetizable substrate body, said substrate surface being substantially planar and having a nominal roughness; depositing a magnetizable film over said substrate surface as a layer substantially uniform in thickness to provide a recording surface; and concentrating radiant energy selectively upon a plurality of locations over a treatment area 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 a distance substantially less than the length dimension and width dimension of a magnetic transducing head positioned proximate said magnetic film for recording and reading magnetic data, the roughness of said selected surface throughout said treatment area being at least twice said nominal roughness.
Claim 2
Dependent Claim
157 words
A process for manufacturing magnetic media operated in conjunction with magnetic transducing heads for the recording and reading of magnetic data, including the steps of: forming a specular substrate surface on a non-magnetizable substrate body, said substrate surface being substantially planar and having a nominal roughness; depositing a magnetizable film over said substrate surface as a layer substantially uniform in thickness to provide a recording surface; and concentrating radiant energy selectively upon a plurality of locations over a treatment area 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 a distance substantially less than the length dimension and width dimension of a magnetic transducing head positioned proximate said magnetic film for recording and reading magnetic data, the roughness of said selected surface throughout said treatment area being at least twice said nominal roughness.
Claim 3
Dependent Claim
27 words
The process of claim 1 wherein: said radiant energy is pulsed laser energy, and forms laser marks comprising rounded depressions in the selected surface at said locations.
Claim 4
Dependent Claim
31 words
The process of claim 2 wherein: said treatment area consists of a designated region of said selected surface comprising less than ten percent of the surface area of the selected surface.
Claim 5
Dependent Claim
149 words
The process of claim 3 wherein: the substrate is a disc, and said step of concentrating energy includes the substeps of: (a) rotating the disc at a controlled rotational velocity; (b) simultaneously providing said pulsed laser energy at a controlled frequency corresponding to the rotational velocity to form a first ring comprised of a series of said depressions; (c) after forming said ring, displacing said laser radially relative to the disc. (d) providing said pulse laser energy at said controlled frequency while rotating said disc at said rotational velocity to form a subsequent ring comprised of a subsequent series of said 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 said designated region is an annular band.
Claim 6
Dependent Claim
37 words
The process of claim 4 wherein: the width dimension of said transducer is aligned substantially radially of the disc, and said band has a width in the radial direction at least as great as said transducer width.
Claim 7
Dependent Claim
108 words
The process of claim 3 wherein: said step of concentrating energy includes the substeps of: (a) moving said substrate at a controlled velocity in longitudinal direction; (b) simultaneously directing a beam of said pulsed laser energy upon said surface at a controlled frequency to form a first row of said depressions; (c) displacing said beam transversely a selected pitch, and providing said beam of laser energy while longitudinally moving said substrate, to form a subsequent row of said depressions parallel to the first row; and (d) repeating step (d) a selected number of time to form the designated region as a longitudinal band of a selected transverse width.
Claim 8
Dependent Claim
16 words
The process of claim 2 wherein: said step of concentrating energy is performed on the substrate.
Claim 9
Dependent Claim
17 words
The process of claim 7 wherein: said substrate body is substantially rigid and is formed of aluminum.
Claim 10
Dependent Claim
39 words
The process of claim 8 wherein: said substrate body further includes a layer of a nickel-phosphorous alloy plated onto the aluminum, as a layer substantially uniform in thickness, said substrate surface being a surface of the nickel-phosphorous alloy layer.
Claim 11
Dependent Claim
36 words
The process of claim 2 including the further step of: 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 12
Dependent Claim
45 words
The process of claim 10 including a further step of: depositing a non-magnetizable underlayer on said substrate surface prior to depositing said magnetizable film over said substrate surface, said non-magnetizable underlayer having a substantially uniform thickness and replicating the surface contours of the substrate surface.
Claim 13
Dependent Claim
49 words
The process of claim 1 wherein: said radiant energy forms, at each of said locations, a rounded central depression extending inwardly of a nominal surface plane of the selected surface, and a generally circular and rounded rim surrounding the central depression and extending outwardly of the nominal surface plane.
Claim 14
Dependent Claim
25 words
The process of claim 12 wherein: said step of concentrating energy includes selecting said locations to distribute the depressions generally uniformly over the designated area.
Claim 15
Dependent Claim
24 words
The process of claim 13 wherein: said step of concentrating energy further includes forming said depressions over at least one-half of the designated region.
Claim 16
Dependent Claim
16 words
The process of claim 1 wherein: said treatment area comprises substantially all of said selected surface.
Claim 17
Dependent Claim
194 words
A process for manufacturing a magnetic disc normally operated in controlled spaced apart relation to a magnetic transducing head for recording and reading magnetic data, including the steps of: forming a substantially planar outer substrate surface on a rigid, non-magnetizable substrate; depositing a non-magnetizable underlayer on said substrate at a generally uniform thickness to provide an outer underlayer surface substantially parallel to said substrate surface; depositing a magnetizable film over said non-magnetizable underlayer, said magnetizable film having a substantially uniform thickness to provide an outer film surface substantially parallel to said underlayer surface; forming a non-magnetizable cover layer over said magnetizable film, said cover layer having a substantially uniform thickness to provide an exposed outer cover surface substantially parallel to said film surface; and concentrating energy upon multiple locations over a selected one of said outer surfaces to form a mark comprising an inwardly extended depression and an outwardly extended rounded rim surrounding the depression at each of the locations, thereby to increase the surface roughness of said selected surface throughout a selected treatment area thereof from a nominal value of at most 0.1 microinches to an enhanced value of at least 0.2 microinches.
Claim 18
Dependent Claim
194 words
A process for manufacturing a magnetic disc normally operated in controlled spaced apart relation to a magnetic transducing head for recording and reading magnetic data, including the steps of: forming a substantially planar outer substrate surface on a rigid, non-magnetizable substrate; depositing a non-magnetizable underlayer on said substrate at a generally uniform thickness to provide an outer underlayer surface substantially parallel to said substrate surface; depositing a magnetizable film over said non-magnetizable underlayer, said magnetizable film having a substantially uniform thickness to provide an outer film surface substantially parallel to said underlayer surface; forming a non-magnetizable cover layer over said magnetizable film, said cover layer having a substantially uniform thickness to provide an exposed outer cover surface substantially parallel to said film surface; and concentrating energy upon multiple locations over a selected one of said outer surfaces to form a mark comprising an inwardly extended depression and an outwardly extended rounded rim surrounding the depression at each of the locations, thereby to increase the surface roughness of said selected surface throughout a selected treatment area thereof from a nominal value of at most 0.1 microinches to an enhanced value of at least 0.2 microinches.
Claim 19
Dependent Claim
41 words
The process of claim 16 wherein: said selected surface is the substrate surface, and said steps of depositing the underlayer, the magnetizable film and the cover layer are performed in succession after the step of concentrating energy on the substrate surface.
Claim 20
Dependent Claim
74 words
The process of claim 17 wherein: the step of concentrating energy upon the substrate surface includes the substeps of: (a) rotating the disc at a predetermined rotational velocity; (b) simultaneously directing a pulsed beam of laser energy upon said substrate surface to form a multiplicity of the marks, one mark corresponding to each of said locations; and (c) varying the radial position of said substrate surface to which said laser energy beam is directed.
Claim 21
Dependent Claim
197 words
A process for manufacturing magnetic media operated in conjunction with magnetic transducing heads for the recording and reading of magnetic data, including the steps of: forming a specular substrate surface on a non-magnetizable substrate body, said substrate surface being substantially planar and having a nominal roughness; depositing a magnetizable film over said substrate surface as a layer substantially uniform in thickness to provide a recording surface; and concentrating energy selectively upon a plurality of locations over a treatment area on a selected one of said substrate surface and recording surface, to form at each said location a rounded central depression extending inwardly of a nominal surface plane of the selected surface and a generally circular and rounded rim surrounding the central depression and extending outwardly of the nominal surface plane, thus to controllably alter the topography of the selected surface at each of the locations, adjacent locations being spaced apart from one another a distance substantially less than the length dimension and width dimension of a magnetic transducing head positioned proximate said magnetic film for recording and reading magnetic data, the roughness of said selected surface throughout said treatment area being at least twice said nominal roughness.
Claim 22
Dependent Claim
197 words
A process for manufacturing magnetic media operated in conjunction with magnetic transducing heads for the recording and reading of magnetic data, including the steps of: forming a specular substrate surface on a non-magnetizable substrate body, said substrate surface being substantially planar and having a nominal roughness; depositing a magnetizable film over said substrate surface as a layer substantially uniform in thickness to provide a recording surface; and concentrating energy selectively upon a plurality of locations over a treatment area on a selected one of said substrate surface and recording surface, to form at each said location a rounded central depression extending inwardly of a nominal surface plane of the selected surface and a generally circular and rounded rim surrounding the central depression and extending outwardly of the nominal surface plane, thus to controllably alter the topography of the selected surface at each of the locations, adjacent locations being spaced apart from one another a distance substantially less than the length dimension and width dimension of a magnetic transducing head positioned proximate said magnetic film for recording and reading magnetic data, the roughness of said selected surface throughout said treatment area being at least twice said nominal roughness.
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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) | 1995-04-28 | 1995-10-28 | 1996-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-28 | 1999-10-28 | 2000-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-28 | 2003-10-28 | 2004-04-28 | $7700.00 | Window Closed / Lapsed |