US4423454A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording disk
Assignee: Emtec Magnetics GmbH
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Filing: 1980-06-26
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Granted: 1983-12-27
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Expires: 2000-06-26
Abstract
Abstract A magnetic recording disk comprising a non-magnetic substrate and two or more firmly adhering magnetizable layers applied to one or both sides thereof, the layer located directly on the substrate being magnetically isotropic, while the second layer and any additional layers exhibit orientation of the anisotropic magnetic particles parallel to the substrate and to the envisaged recording direction.
Inventors
- 👤 Peter Felleisen
- 👤 Dieter Mayer
- 👤 Eberhard Koester
- 👤 Friedrich Domas
- 👤 Paul Deigner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/716; G11B5/718; G11B5/84; G11B5/842; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
95 words
A magnetic recording disk comprising a non-magnetic substrate and at least two firmly adhering magnetizable layers applied to one or both sides thereof, wherein the layer located directly on the substrate is magnetically isotropic and exhibits a random orientation with no magnetic preferred direction, whilst the second layer exhibits orientation of the anisotropic magnetic particles parallel to the substrate and parallel to the envisaged recording direction, such that relatively low frequency signals are magnetically, longitudinally stored predominantly within the isotropic layer whereas relatively high frequency signals are magnetically, longitudinally stored predominantly within the anisotropic layer.
Claim 2
Dependent Claim
95 words
A magnetic recording disk comprising a non-magnetic substrate and at least two firmly adhering magnetizable layers applied to one or both sides thereof, wherein the layer located directly on the substrate is magnetically isotropic and exhibits a random orientation with no magnetic preferred direction, whilst the second layer exhibits orientation of the anisotropic magnetic particles parallel to the substrate and parallel to the envisaged recording direction, such that relatively low frequency signals are magnetically, longitudinally stored predominantly within the isotropic layer whereas relatively high frequency signals are magnetically, longitudinally stored predominantly within the anisotropic layer.
Claim 3
Dependent Claim
25 words
A disk as claimed in claim 1 wherein there is provided a plurality of anisotropic layers having orientation ratios improving upwardly from layer to layer.
Claim 4
Dependent Claim
47 words
A disk as claimed in claim 1 or 2 wherein said layers consist essentially of magnetic materials finely dispersed in a polymeric binder with conventional additives and such that said magnetic particles contained in said magnetic material are circularly oriented parallel to the plane of the substrate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-26 | 1987-06-27 | 1987-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-26 | 1991-06-27 | 1991-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-26 | 1995-06-27 | 1995-12-27 | $7700.00 | Window Closed / Lapsed |