Inductor devices – Coil or coil turn supports or spacers – Printed circuit-type coil
Reexamination Certificate
1998-07-23
2001-01-30
Gellner, Michael L. (Department: 2832)
Inductor devices
Coil or coil turn supports or spacers
Printed circuit-type coil
C336S083000, C336S212000, C336S223000
Reexamination Certificate
active
06181232
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to coil elements, for example, transformers and common mode choke coils.
2. Description of the Related Art
FIG. 4
is a perspective view which shows an example of a common mode choke coil comprising a coil element, and
FIG. 5
is an assembly view of the common mode choke coil shown in FIG.
4
. The common mode choke coil
1
is disclosed in Japanese Patent Publication No.8-203737, and includes, as shown in
FIG. 4
, a composite member
7
disposed on a first magnetic substrate
3
, a second magnetic substrate
10
disposed on the composite member
7
and an adhesive layer
8
located therebetween, and external electrodes
11
located on the outer surfaces of the first magnetic substrate
3
, the composite member
7
, the adhesive layer
8
, and the second magnetic substrate
10
.
As shown in
FIG. 5
, the composite member
7
includes a plurality of layers deposited by a thin-film fabricating technique such as sputtering, wherein an insulating layer
6
a
composed of a non-magnetic insulating material, for example, a polyimide resin and an epoxy resin, is deposited on the first magnetic substrate
3
, leading electrodes
12
a
and
12
b
are disposed on the insulating layer
6
a,
an insulating layer
6
b
is disposed on the leading electrodes
12
a
and
12
b,
a coil pattern
4
and a leading electrode
12
c
extending from the coil pattern
4
are disposed on the insulating layer
6
b,
an insulating layer
6
c
is disposed on the coil pattern
4
and the leading electrode
12
c,
and a coil pattern
5
and a leading electrode
12
d
extending from the coil pattern
5
are disposed on the insulating layer
6
c.
One end of the coil pattern
4
is electrically connected to the leading electrode
12
a
through a via hole
13
a
provided in the insulating layer
6
b
and the leading electrode
12
a
is electrically connected to an external electrode
11
a.
The other end of the coil pattern
4
is electrically connected to an external electrode
11
c
via the leading electrode
12
c.
One end of the coil pattern
5
is electrically connected to the leading electrode
12
b
through a via hole
13
c
provided in the insulating layer
6
c
and a via hole
13
b
provided in the insulating layer
6
b,
and the leading electrode
12
b
is connected to an external electrode
11
b.
The other end of the coil pattern
5
is electrically connected to an external electrode
11
d
via the leading electrode
12
d.
When the common mode choke coil
1
is assembled into a circuit by electrically connecting the individual external electrodes
11
to respective connectors of the circuit, the coil pattern
4
and the coil pattern
5
are assembled into the circuit.
Since the common mode choke coil
1
can be manufactured by a thin-film fabricating technique, for example, sputtering and evaporation, it is easily miniaturized and high productivity can be obtained.
It is important to increase the degree of electromagnetic coupling between coil patterns in a coil element such as, for example, a common mode choke coil or a transformer to improve the electrical characteristics of the coil element. For example, the above-mentioned common mode choke coil can be configured so as to have a high impedance to common mode noise, and thus, the capability of the coil element eliminating common mode noise can be enhanced. Also, a transformer can be configured so as to decrease an energy loss and to increase a bandwidth thereof.
In the common mode choke coil
1
shown in FIG.
4
and
FIG. 5
, since the insulating layers
6
can be made by a thin-film fabricating technique as described above, the thicknesses of the insulating layers
6
can be reduced. That is, the space between the coil pattern
4
and the coil pattern
5
can be reduced. As the space between the coil patterns
4
and
5
becomes narrower, the degree of electromagnetic coupling between the coil patterns
4
and
5
increases, and thus, the impedance of the common mode choke coil
1
can be increased.
However, in order to reliably provide a certain minimum required insulation quality between the coil pattern
4
and the coil pattern
5
, the thicknesses of the insulating layers
6
cannot be reduced limitlessly. Therefore, in the method for increasing the degree of electromagnetic coupling by reducing the thicknesses of the insulating layers
6
, and increasing the impedance of the common mode choke coil
1
, there are limits to an amount of improvement to the electromagnetic coupling and impedance characteristics. As a result, satisfactory elimination of common mode noise cannot be achieved.
SUMMARY OF THE INVENTION
The preferred embodiments of the present invention overcome the problems described above by providing a coil element which has excellent electrical characteristics obtained by significantly improving the degree of electromagnetic coupling between coil patterns to meet the demand for a common mode choke coil having higher impedance.
To solve the problems of the prior art, the preferred embodiments of the present invention a coil element includes a composite member disposed on a first magnetic substrate. The composite member includes coil patterns and insulating layers which are alternately arranged. A second magnetic substrate is disposed on the composite member with an adhesive layer disposed therebetween. The adhesive layer preferably includes a material having a relative magnetic permeability of more than about 1.0.
In another preferred embodiment, a coil element includes a composite member disposed on a first magnetic substrate. The composite member includes coil patterns and insulating layers which are alternately arranged. A second magnetic substrate is disposed on the composite member with an adhesive layer disposed therebetween. The adhesive layer is composed of a material having a relative magnetic permeability of more than about 1.0, and the insulating layers, excluding a portion which surrounds an overlapping region of the coil patterns, are composed of a material having a relative magnetic permeability of more than about 1.0.
In accordance with another preferred embodiment of the present invention, a coil element includes a composite member disposed on a first magnetic substrate. The composite member includes coil patterns and insulating layers being alternately arranged. A second magnetic substrate is disposed on the composite member with an adhesive layer therebetween. The adhesive layer is composed of a material having a relative magnetic permeability of more than about 1.0, and the insulating layers are provided with holes formed in the central regions surrounded by the coil patterns. The holes in the insulating layers are filled with the material of the adhesive layer.
In accordance with another preferred embodiment of the present invention, a coil element is provided with the structure according to the preferred embodiments described above, wherein the material having a relative magnetic permeability of more than about 1.0 is an insulating material which contains magnetic particles.
In accordance with a fifth aspect of the present invention, the magnetic particles according to the fourth aspect of the present invention are composed of a ferrite. The ferrite magnetic particles according to this preferred embodiment may be Ni—Zn-based or Mn—Zn-based ferrite magnetic particles.
In accordance with preferred embodiments of the present invention having the structures described above, at least the adhesive layer is composed of a material having a relative magnetic permeability of more than about 1.0. Magnetic lines of force generated by the coil patterns form a closed magnetic circuit, for example, which starts from the first magnetic substrate, passes through the insulating layers of the composite member and the adhesive layer in the central region surrounded by coil patterns to reach the second magnetic substrate, passes through the second magnetic substrate, passes through the adhesive layer and the insulating layers of the composite
Gellner Michael L.
Keating & Bennett LLP
Mai Anh
Murata Manufacturing Co. Ltd.
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