Patent EP0785557A1 successfully refreshed from Google Patents.
EP0785557A1
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EP
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Composite magnetic material and product for eliminating electromagnetic interference
Assignee: Tokin Corp
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Filing: 1996-07-22
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Granted: —
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Expires: 2016-07-22
Abstract
Abstract A composite magnetic material is provided for use as an electromagnetic interference suppressor member for effectively suppressing an electromagnetic interference within a high frequency apparatus including a mobile communication terminal. The composite magnetic material consists essentially of a soft magnetic powder and an organic binder and is electrically non-conductive and has at least two magnetic resonances caused by at lest two anisotropic magnetic fields (Hk). In the composite magnetic material, the anisotropic magnetic fields (Hk) are different in strength from each other. <IMAGE>
Inventors
- 👤 Shigeyoshi Yoshida
- 👤 Mitsuharu Sato
- 👤 Eishu Sugawara
- 👤 Yutaka Shimada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 12:36
CPC Classifications
H; H05; H05K; H05K9/00; H05K9/0073; H05K9/0081; H05K9/0083; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/20; H01F1/22; H01F1/24; H01F1/26; H01F1/34; H01F1/36; H01F1/37; H05K1/00; H05K1/02; H05K1/0213; H05K1/0216; H05K1/023; H05K1/0233; H10; H10W; H10W42/00; H10W42/20; H10W42/281; H10W42/287; H10W44/00; H10W44/20; H05K1/03; H05K1/0313; H05K1/0353; H05K1/0373; H05K2201/00; H05K2201/08; H05K2201/083; H05K2201/086; H05K2201/10; H05K2201/10613; H05K2201/10621; H05K2201/10689
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
36 words
A composite magnetic material consisting essentially of a soft magnetic powder and an organic binder, said composite magnetic material having electrical non-conductivity and having at least two magnetic resonances in frequency regions different from each other.
Claim 2
Dependent Claim
33 words
A composite magnetic material as claimed in claim 1, wherein said magnetic resonances in frequency regions different from each other are caused by anisotropic magnetic fields (Hk) different in strengths from each other.
Claim 3
Dependent Claim
59 words
An electromagnetic interference suppressor member comprising a composite magnetic material, said composite magnetic material having electrical non-conductivity and consisting essentially of a soft magnetic powder and an organic binder, said electromagnetic interference suppressor member having at least two magnetic resonances in a microwave frequency region by at least two anisotropic magnetic fields (Hk) different in strength from each other.
Claim 4
Dependent Claim
76 words
An electromagnetic interference suppressor member as claimed in claim 3, wherein said composite magnetic material has a plurality of magnetic resonances, said plurality of magnetic resonances occurring in different frequency regions corresponding to the anisotropic magnetic fields of different strength of anisotropic magnetic fields, respectively, the lowest one of said magnetic resonances occurring in a frequency region lower than a lower limit of the electromagnetic interference suppression frequency band caused by said magnetic interference suppressor member.
Claim 5
Dependent Claim
35 words
An electromagnetic interference suppressor member as claimed in claim 4, wherein said soft magnetic powder is a mixture of at least two kinds of soft magnetic powder having different anisotropy in strength from each other.
Claim 6
Dependent Claim
19 words
A magnetic interference suppressor member as claimed in claim 5, wherein said soft magnetic powder has surface oxide layer.
Claim 7
Independent Claim
68 words
A method of producing a composite magnetic material comprising the steps of, mixing at least two kinds of soft magnetic powder having the magnetic anisotropy different in strength from each other and an organic binder, and shaping the mixture to produce said composite magnetic material which is electrically non-conductive and has at least two magnetic resonances given by anisotropic magnetic fields (Hk) with strengths different from each other.
Claim 8
Dependent Claim
16 words
A method as claimed in claim 7, wherein said soft magnetic powder has surface oxide layer.
Claim 9
Dependent Claim
48 words
A method as claimed in claim 7, further comprising a step of oxidizing said soft magnetic powder in an gas atmosphere containing oxygen by use of a process of vapor-phase-slow-oxidation or liquid-phase-slow-oxidation before or during the step of the mixing said soft magnetic powder with said organic binder.
Claim 10
Dependent Claim
87 words
A printed circuit board comprising a printed wiring substrate, wiring conductors on at least one surface thereof, a conductive support and layers of composite soft magnetic material formed on both surfaces of said conductive support, said composite magnetic material having insulation, each of said composite magnetic layers comprising a composite magnetic material which consists essentially of a soft magnetic powder and an organic binder and has electrical non-conductivity, and at least two magnetic resonances caused by at least two anisotropic magnetic fields (Hk) different from each other.
Claim 11
Dependent Claim
23 words
A printed circuit board as claimed in claim 10, wherein at least one of said layers has a dielectric layer on the surface.
Claim 12
Dependent Claim
20 words
A printed circuit board as claimed in claim 10, wherein at least one of said layers contains a dielectric powder.
Claim 13
Dependent Claim
70 words
A printed circuit board as claimed in claim 10, wherein said composite magnetic material has a plurality of magnetic resonances, said plurality of magnetic resonances occurring in different frequency regions corresponding to anisotropic magnetic fields different in strength from each other, the lowest one of said magnetic resonances being in a frequency region lower than a lower limit of electromagnetic interference suppression frequency band caused by said composite magnetic material.
Claim 14
Dependent Claim
35 words
A printed circuit board as claimed in claim 13, wherein said soft magnetic powder is a mixture of at least two kinds of soft magnetic powder having magnetic anisotropy different in strength from each other.
Claim 15
Dependent Claim
34 words
A printed circuit board as claimed in claim 14, wherein said soft magnetic powder is at least one powders selected from the group of Sendust, iron-nickel alloy, spinel type ferrite, and planar type ferrite.
Claim 16
Dependent Claim
83 words
An electronic apparatus comprising a printed circuit board and an active element mounted on said printed circuit hoard, said active element radiating an inductive noise, said electronic apparatus further comprising an insulating soft magnetic layer formed around said active element, said composite magnetic material layer consisting essentially of a soft magnetic powder and an organic binder, and having electrical non-conductivity and at least two magnetic resonances which are caused by at least two anisotropic magnetic fields (Hk) different in strength from each other.
Claim 17
Dependent Claim
74 words
An electronic apparatus as claimed in claim 16, wherein said composite magnetic material has a plurality of magnetic resonances, said plurality of magnetic resonances occurring in frequency regions different from each other corresponding to anisotropic magnetic fields different in strength from each other, the lowest one of said magnetic resonances being in a frequency region lower than a lower limit of an electromagnetic interference suppression frequency band caused by said composite magnetic material layer.
Claim 18
Dependent Claim
34 words
An electronic apparatus as claimed in claim 17, wherein said soft magnetic powder is a mixture of at least two kinds of soft magnetic powder having magnetic anisotropy different in strength from each other.
Claim 19
Dependent Claim
33 words
An electronic apparatus as claimed in claim 18, wherein said soft magnetic powder is at least one powder selected from the group of Sendust, iron-nickel alloy, spinel type ferrite, and planar type ferrite.
Claim 20
Dependent Claim
25 words
An electronic apparatus as claimed in claim 16, wherein said composite magnetic material layer is formed between said printed circuit board and said active element.
Claim 21
Dependent Claim
34 words
An electronic apparatus as claimed in claim 16, wherein said printed circuit board has a plurality of conductive patterns on the surface thereof, said composite magnetic material layer being formed between said conductive patterns.
Claim 22
Dependent Claim
31 words
An electronic apparatus as claimed in claim 16, wherein said composite magnetic material layer is formed inside a cover, said cover covering said active element together with said printed circuit board.
References Cited (Backward Citations)
No citation records indexed.
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