US4522848A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of preparing a recording member having a variable thickness recording layer
Assignee: Poly-Disc Systems Inc
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Filing: 1983-04-28
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Granted: 1985-06-11
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Expires: 2003-04-28
Abstract
Abstract A magnetic recording disk is constructed wherein a disk substrate is overlayed with at least one non-recording layer. A recording layer is then overlayed on the non-recording layer with the thickness of the recording layer at those areas corresponding to the inner track zone located toward the central hub area of the disk being thinner than the intermediate track zone radially displaced outwardly from the inner track zone toward the periphery of the recording disk.
Inventors
- 👤 Pravin K. Patel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:04
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/656; G11B5/73; G11B5/7368; G11B5/74; G11B5/82; G11B5/84; G11B5/858
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
134 words
A process of preparing a magnetic recording disk which comprises: electrolessly depositing upon a disk shaped substrate a metal containing non-recording support layer; contacting said support layer with an anodic metal, said anodic metal comprising a metal which is more electro-positive than cobalt, said support layer contacted at an area proximal to that area which will underlay the inner track zone of said recording disk, said contact with said anodic material producing an area of positive charge at said area of said support layer which will underlay said inner track zone; electrolessly depositing upon said support layer a cobalt containing recording layer, the thickness of said cobalt containing recording layer at said area of positive charge being less than the thickness of said cobalt containing recording layer overlaying the remainder of said support layer.
Claim 2
Dependent Claim
134 words
A process of preparing a magnetic recording disk which comprises: electrolessly depositing upon a disk shaped substrate a metal containing non-recording support layer; contacting said support layer with an anodic metal, said anodic metal comprising a metal which is more electro-positive than cobalt, said support layer contacted at an area proximal to that area which will underlay the inner track zone of said recording disk, said contact with said anodic material producing an area of positive charge at said area of said support layer which will underlay said inner track zone; electrolessly depositing upon said support layer a cobalt containing recording layer, the thickness of said cobalt containing recording layer at said area of positive charge being less than the thickness of said cobalt containing recording layer overlaying the remainder of said support layer.
Claim 3
Dependent Claim
53 words
The process of claim 1 wherein: said depositing of said recording layer is inhibited at said area of positive charge such that the thickness of said recording layer deposited at said area of positive charge is from about 5% to about 20% less than the thickness of the remainder of said recording layer.
Claim 4
Dependent Claim
37 words
The process of claim 2 wherein: said thickness of said recording layer deposited at said area of positive charge is from about 10% to about 15% less than the thickness of the remainder of said recording layer.
Claim 5
Dependent Claim
75 words
The process of claim 3 including: said substrate disk having a central opening; said anodic metal shaped as a mandrel capable of fitting into said central opening in said substrate disk and contacting said central opening to produce said area of positive charge about said central opening; locating said substrate disk containing said support layer on said mandrel to produce said area of positive charge prior to depositing said recording layer on said support layer.
Claim 6
Dependent Claim
15 words
The process of claim 4 including: electrolessly depositing a further layer onto said recording layer.
Claim 7
Dependent Claim
51 words
The process of claim 3 including: forming said substrate disk from said anodic metal; forming said support layer to include a discontinuity in said support layer to expose said anodic metal substrate disk at said discontinuity to create said area of positive charge proximal to said discontinuity in said support layer.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-10 | 1988-12-10 | 1989-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-10 | 1992-12-10 | 1993-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-10 | 1996-12-10 | 1997-06-11 | $7700.00 | Window Closed / Lapsed |