US4588653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic memory disk
Assignee: NORTHWEST VENTURE PARTNERS A LP
•
Filing: 1984-06-11
•
Granted: 1986-05-13
•
Expires: 2004-06-11
Abstract
Abstract A magnetic memory disk which has controlled magnetic characteristics in the radial direction is provided by controlling the thickness and composition of the magnetic layer which is formed on the disk. The thickness of the layer may be varied in the radial direction to control the remanence of the disk and the composition of the magnetic layer varied to control the coercivity of the disk. The magnetic layer is formed by an electroplating operation employing one or more rotating apertured masks in an electrolyte solution between an anode and a disk (cathode) which is to be plated. The thickness of the plated layer is determined by the configuration of the apertures in the mask, and the relative composition of the layer is determined by the variation and distance of the mask to the disk in the radial direction. Thickness characteristics of layers other than the magnetic layer may also be precisely controlled in the radial direction to achieve desired characteristics.
Inventors
- 👤 Daniel X. Wray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:07
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/858; C; C25; C25D; C25D17/00; C25D17/008; C25D5/00; C25D5/02; C25D5/022; C25D7/00; C25D7/001; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12389; Y10T428/12458; Y10T428/12493; Y10T428/12736; Y10T428/12771; Y10T428/12785; Y10T428/12792; Y10T428/12861; Y10T428/12944
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
69 words
A magnetic memory disk, comprising: a disk-shaped substrate; an electroplated base layer over a surface of the disk; and an electroplated magnetic layer formed on the base layer, said magnetic layer comprising an alloy of at least two metals varying in relative concentrations in the alloy in a controlled fashion radially along the disk and providing a controlled varying value of coercivity in the radial direction of the disk.
Claim 2
Dependent Claim
69 words
A magnetic memory disk, comprising: a disk-shaped substrate; an electroplated base layer over a surface of the disk; and an electroplated magnetic layer formed on the base layer, said magnetic layer comprising an alloy of at least two metals varying in relative concentrations in the alloy in a controlled fashion radially along the disk and providing a controlled varying value of coercivity in the radial direction of the disk.
Claim 3
Dependent Claim
15 words
A magnetic memory disk according to claim 1 wherein the alloy includes cobalt and nickel.
Claim 4
Dependent Claim
37 words
A disk according to claim 1 wherein the magnetic layer has a predetermined thickness which varies in a controlled fashion in the radial direction to provide predetermined remanence characteristics which vary along the radius of the disk.
Claim 5
Dependent Claim
36 words
A disk according to claim 1, wherein the substrate is aluminum and including a zinc layer formed on the surface of the substrate, wherein said base layer is formed on the surface of the zinc layer.
Claim 6
Dependent Claim
81 words
A magnetic memory disk, comprising: a disk-shaped substrate; an electroplated base layer formed over a surface of the substrate; and an electroplated magnetic layer formed on the base layer, said magnetic layer having a controlled varying thickness in the radial direction to provide predetermined magnetic response characteristics, said magnetic layer being comprised of an alloy of at least two metals, wherein the relative concentration of the metals varies in a controlled fashion in the radial direction to provide predetermined coercivity characteristics.
Claim 7
Dependent Claim
81 words
A magnetic memory disk, comprising: a disk-shaped substrate; an electroplated base layer formed over a surface of the substrate; and an electroplated magnetic layer formed on the base layer, said magnetic layer having a controlled varying thickness in the radial direction to provide predetermined magnetic response characteristics, said magnetic layer being comprised of an alloy of at least two metals, wherein the relative concentration of the metals varies in a controlled fashion in the radial direction to provide predetermined coercivity characteristics.
Claim 8
Dependent Claim
15 words
A memory disk according to claim 5 wherein the magnetic layer includes cobalt and nickel.
Claim 9
Dependent Claim
16 words
A memory disk according to claim 5 wherein the magnetic layer includes cobalt, nickel and phosphorus.
Claim 10
Dependent Claim
36 words
A disk according to claim 5, wherein the substrate is aluminum and including a zinc layer formed on the surface of the substrate, wherein said base layer is formed on the surface of the zinc layer.
References Cited (Backward Citations)
CA615314A
Cited
US3466156A
Cited
US4029541A
Cited
JPS5212802A
Cited
US4144160A
Cited
JPS5573931A
Cited
EP0026496A1
Cited
JPS56156934A
Cited
EP0041321A1
Cited
US4304641A
Cited
JPS56156935A
Cited
JPS5774831A
Cited
JPS5885933A
Cited
US4359375A
Cited
JPS58164032A
Cited
US4469566A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-12 | 1989-11-11 | 1990-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-12 | 1993-11-11 | 1994-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-12 | 1997-11-11 | 1998-05-13 | $7700.00 | Window Closed / Lapsed |