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US4656547A
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US
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Composite type magnetic head for recording and reproducing high frequency signals
Assignee: Hitachi Ltd
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Filing: 1984-05-09
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Granted: 1987-04-07
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Expires: 2004-05-09
Abstract
Abstract There is provided a structure of a composite type magnetic head and its manufacturing method. The composite type magnetic head comprises: two high permeability ferrite blocks with projections having nearly edged sections formed thereon; magnetic films having a high saturation flux density deposited on the side faces of the projections, the magnetic films confronting each other via a functional gap near front ends of said projections; guard films deposited over the magnetic films comprising a non-magnetic material; and non-magnetic materials filled on the guard films up to side face of the coil. This magnetic head exhibits excellent recording and reproducing characteristics. The contour effect is negligibly small. The reaction between the magnetic film and the non-magnetic material is prevented by the guard film.
Inventors
- 👤 Noriyuki Kumasaka
- 👤 Hideo Fujiwara
- 👤 Shigekazu Otomo
- 👤 Takeo Yamashita
- 👤 Shinji Takayama
- 👤 Noritoshi Saito
- 👤 Mitsuhiro Kudo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:05
CPC Classifications
A; A01; A01K; A01K89/00; A01K89/01; G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/1871; G11B5/1872; G11B5/1874
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
156 words
A composite type magnetic head comprising: two high permeability ferrite blocks having projections projecting towards each other in a sectional view seen from a side of a surface facing a magnetic recording medium, said ferrite blocks at a front end of each of said projections having a width smaller than a track width of a recording track of the magnetic recording medium; magnetic substances deposited over at least both side faces of said projections of said ferrite blocks, each of said magnetic substances having a saturation flux density larger than that of said ferrite blocks, said magnetic substances confronting each other via a functional gap near front ends of said projection; guard films deposited over said magnetic substances around side faces of said projections of said ferrite blocks, said guard films comprising a non-magnetic material; and non-magnetic materials filled over said guard films up to a side face of a core formed by said ferrite blocks.
Claim 2
Dependent Claim
156 words
A composite type magnetic head comprising: two high permeability ferrite blocks having projections projecting towards each other in a sectional view seen from a side of a surface facing a magnetic recording medium, said ferrite blocks at a front end of each of said projections having a width smaller than a track width of a recording track of the magnetic recording medium; magnetic substances deposited over at least both side faces of said projections of said ferrite blocks, each of said magnetic substances having a saturation flux density larger than that of said ferrite blocks, said magnetic substances confronting each other via a functional gap near front ends of said projection; guard films deposited over said magnetic substances around side faces of said projections of said ferrite blocks, said guard films comprising a non-magnetic material; and non-magnetic materials filled over said guard films up to a side face of a core formed by said ferrite blocks.
Claim 3
Dependent Claim
26 words
A composite type magnetic head according to claim 1, wherein the width of said projections becomes larger as the distance from said functional gap is increased.
Claim 4
Dependent Claim
20 words
A composite type magnetic head according to claim 2, wherein a functional gap plane is formed by said magnetic substances.
Claim 5
Dependent Claim
31 words
A composite type magnetic head according to claim 3, wherein the width of said ferrite at the front ends of said projections is not larger than half of the track width.
Claim 6
Dependent Claim
25 words
A composite type magnetic head according to claim 3, wherein the width of said ferrite at the front ends of said projections is nearly zero.
Claim 7
Dependent Claim
25 words
A composite type magnetic head according to claim 2, wherein the thickness of said magnetic substances is not larger than half of the track width.
Claim 8
Dependent Claim
23 words
A composite type magnetic head according to claim 5, wherein the thickness of said magnetic substances is nearly half of the track width.
Claim 9
Dependent Claim
24 words
A composite type magnetic head according to claim 2, wherein a functional gap forming surface is formed by said magnetic substance and said ferrite.
Claim 10
Dependent Claim
42 words
A composite type magnetic head according to claim 8, wherein the width of said magnetic substance of said functional gap plane in the track width direction is at least twice the width of said ferrite at the front end of said projection.
Claim 11
Dependent Claim
20 words
A composite type magnetic head according to claim 2, wherein said high permeability ferrite comprises Mn-Zn ferrite or Ni-Zn ferrite.
Claim 12
Dependent Claim
27 words
A composite type magnetic head according to claim 2, wherein said magnetic substance comprises a Fe-Si alloy, Fe-Al-Si alloy, Ni-Fe alloy, or a high permeability amorphous alloy.
Claim 13
Dependent Claim
41 words
A composite type magnetic head according to claim 2, wherein the front end of each of said ferrite projections has at least one indentation that is indented from an operation gap when seen from a side facing the magnetic recording medium.
Claim 14
Dependent Claim
19 words
A composite magnetic head according to claim 2, wherein a magnetic substance forms a loop around said coil-winding window.
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) | 1990-04-06 | 1990-10-06 | 1991-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-06 | 1994-10-06 | 1995-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-06 | 1998-10-06 | 1999-04-07 | $7700.00 | Window Closed / Lapsed |