Patent US3781476A successfully refreshed from Google Patents.
US3781476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head having a combination core formed from a pretreated magnetic layer
Assignee: Hitachi Ltd
•
Filing: 1971-12-27
•
Granted: 1973-12-25
•
Expires: 1991-12-27
Abstract
Abstract A magnetic head for use in a magnetic disc of a computer, a magnetic drum or a video tape recorder manufactured through by a thin film technique. A first portion of the magnetic core thereof is a pretreated rolled permalloy which reduces the magnetic reluctance of the core to almost one-half of that of the conventional cores. This first portion taken with a second portion form a somewhat U-shaped core. Between the open ends is disposed a conductive layer surrounded by one or more dielectric layers. A supporting insulating layer may be provided over the second portion of the core.
Inventors
- 👤 M Hanazono
- 👤 O Asai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:55
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3163; G11B5/3109; G11B5/313
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
16 words
A magnetic head according to claim 1 wherein said first pretreated magnetic sheet is rolled permalloy.
Claim 2
Dependent Claim
18 words
A magnetic head according to claim 1 further comprising a supporting insulating layer formed over said magnetic layer.
Claim 3
Dependent Claim
32 words
A magnetic head according to claim 1 wherein said pre-treated magnetic sheet is selected from the group consisting of permalloy and alloys of Ni-Fe-Mo, Ni-Co, Fe-Ni-Co-Al, Cu, Fe-Cu-Ni, Fe-Cu-Ni-Co, Fe-Co or Mn-Bi.
Claim 4
Dependent Claim
30 words
A magnetic head according to claim 1 wherein said first and second dielectric film layers are selected from the group consisting of SiO2, Al2O3, Ta2O3, TaN, ZnFe2O4, CdFe2O5 and glass.
Claim 5
Dependent Claim
24 words
A magnetic head according to claim 1 wherein said magnetic layer is selected from the group permalloy, MnFeO4, NiFe2O4, (NiZn)Fe2O4 or alloys of Ni-Co.
Claim 6
Dependent Claim
40 words
A magnetic head according to claim 1, wherein the pretreated magnetic substrate sheet has a magnetic path length approximately one-half the total magnetic path length of a magnetic core member formed of the magnetic substrate sheet and the magnetic layer.
Claim 7
Dependent Claim
21 words
A magnetic head according to claim 7, wherein the magnetic core member has a magnetic reluctance which is reduced by one-half.
Claim 8
Dependent Claim
167 words
A magnetic head comprising: a pretreated magnetic substrate sheet having a first edge and a second edge located at opposite sides of the major surfaces thereof, said magnetic substrate sheet having a high magnetic permeability; a first dielectric film disposed on said magnetic sheet extending to said first edge but not to said second edge thereof such that the surface portion of said magnetic sheet adjacent said second edge is uncovered by said first dielectric film; a conductive layer formed on a central portion of said first dielectric film such that first and second surface portions of said first dielectric film respectively juxtaposed to said first edge and the exposed surfacE portion of said magnetic sheet are exposed; a second dielectric film formed over said conductive layer and the first and second exposed portions of said first dielectric film; a magnetic layer disposed on said second dielectric film and in contact with that part of the uncovered portion of said magnetic sheet adjacent said first dielectric film.
Claim 9
Dependent Claim
30 words
A magnetic head according to claim 9 further comprising a third dielectric film disposed on the surface of said magnetic sheet between said second edge thereof and said magnetic layer.
Claim 10
Dependent Claim
18 words
A magnetic head according to claim 9 further comprising a supporting insulating layer provided over said magnetic layer.
Claim 11
Dependent Claim
24 words
A magnetic head according to claim 11 wherein said supporting layer extends laterally beyond the intersection of said magnetic sheet and said magnetic 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) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |