US4670807A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic write head with smooth frequency response
Assignee: US Philips Corp
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Filing: 1985-01-10
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Granted: 1987-06-02
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Expires: 2005-01-10
Abstract
Abstract A core of a soft-magnetic material with a comparatively low saturation magnetization has layers of a soft-magnetic material with a higher saturation magnetization on the gap-bounding faces. To compensate for the uneven frequency response cause by the non-magnetic transition zones between the material of the core and the layers of soft-magnetic material, the layers of soft-magnetic material on the gap-bounding faces have different thicknesses.
Inventors
- 👤 Frederik W. Gorter
- 👤 Jean-Paul G. R. Morel
- 👤 Jacobus J. M. Ruigrok
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:34
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/265; G11B5/2652; G11B5/187; G11B5/1875
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
198 words
A magnetic head including a core of a soft-magnetic material with a comparatively low saturation magnetization, for writing signals on a magnetic medium during relative motion between the medium and said head in a given direction, said core having two gap-bounding faces extending transversely to said direction, each of said gap-bounding faces being coated with a respective layer of soft-magnetic material having a higher saturation magnetization than the material of the core, said layers defining a gap therebetween, said gap having a given thickness in said direction, and the head further having two respective transition zones which are poor magnetic conductors formed between the gap bounding faces and the respective layers of soft-magnetic material, said zones having a thickness in said direction substantially less than said given thickness, said zones being formed by intermediate layers of non-magnetic material which are applied to said gap bounding faces of the core to bond the respective layers of soft-magnetic material to the material of the core, said layers of soft-magnetic material having thicknesses, in said given direction, which differ in a ratio of at least 1.15 to 1, the exact ratio being determined by the desired frequency characteristic of the head.
Claim 2
Dependent Claim
198 words
A magnetic head including a core of a soft-magnetic material with a comparatively low saturation magnetization, for writing signals on a magnetic medium during relative motion between the medium and said head in a given direction, said core having two gap-bounding faces extending transversely to said direction, each of said gap-bounding faces being coated with a respective layer of soft-magnetic material having a higher saturation magnetization than the material of the core, said layers defining a gap therebetween, said gap having a given thickness in said direction, and the head further having two respective transition zones which are poor magnetic conductors formed between the gap bounding faces and the respective layers of soft-magnetic material, said zones having a thickness in said direction substantially less than said given thickness, said zones being formed by intermediate layers of non-magnetic material which are applied to said gap bounding faces of the core to bond the respective layers of soft-magnetic material to the material of the core, said layers of soft-magnetic material having thicknesses, in said given direction, which differ in a ratio of at least 1.15 to 1, the exact ratio being determined by the desired frequency characteristic of the head.
Claim 3
Dependent Claim
26 words
A head as claimed in claim 1, characterized in that the ratio of the thicknesses of said layers of soft-magnetic material is between 1.15 and 2.
Claim 4
Dependent Claim
15 words
A head as claimed in claim 2, characterized in that said ratio is approximately 1.25.
Claim 5
Dependent Claim
46 words
A head as claimed in claim 1, characterized in that said transition zones are formed by intermediate layers of non-magnetic material which are applied to said gap bounding faces of the core to bond the respective layers of soft-magnetic material to the material of the core.
Claim 6
Dependent Claim
18 words
A head as claimed in claim 4 wherein the transition zones are of at least approximately equal thickness.
Claim 7
Dependent Claim
29 words
A head as claimed in claim 1, wherein the thickest layer of soft magnetic material is provided on that side of the gap where the tape leaves the gap.
Claim 8
Dependent Claim
18 words
A head as claimed in claim 6, wherein the transition zones are of at least approximately equal thickness.
References Cited (Backward Citations)
NL92346C
Cited
US3143603A
Cited
US4180835A
Cited
SU652605A1
Cited
JPS57103116A
Cited
JPS58159219A
Cited
WO1983003918A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-01 | 1990-12-01 | 1991-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-01 | 1994-12-01 | 1995-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-01 | 1998-12-01 | 1999-06-02 | $7700.00 | Window Closed / Lapsed |