Lamination type inductor array

Details Lamination type inductor array Lamination type inductor array

1999-07-02

2001-02-20

Pascal, Robert (Department: 2817)

Wave transmission lines and networks

Coupling networks

Frequency domain filters utilizing only lumped parameters

C336S232000

Reexamination Certificate

active

06191667

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lamination type inductor array and more particularly, to a lamination type inductor array to be used as a noise filter or other electronic component in high-frequency electronic circuits and other electronic circuits.
2. Description of the Related Art
One example of such a conventional lamination type inductor array is shown in
FIGS. 10 and 11
. This lamination type inductor array
15
includes a first insulating sheet
1
having internal conductors
5
a
-
8
a
disposed on a surface thereof, a second insulating sheet
2
having second internal conductors
5
b
-
8
b
disposed on a surface thereof, and a protective sheet
3
. The linear internal conductors
5
a
-
8
a
and
5
b
-
8
b
are arranged so as to extend from and to opposite edges of the sheets
1
,
2
, respectively.
The sheets
1
-
3
are stacked on one another, and are integrally baked to define a laminated body
10
as shown in FIG.
11
. On the opposite side surfaces of the laminated body
10
, external input electrodes
11
a
-
14
a
and external output electrodes
11
b
-
14
b
are provided, respectively. The internal conductors
5
a
and
5
b
are connected in parallel between the external electrodes
11
a
and
11
b,
and define a linear inductor
5
. The internal conductors
6
a
and
6
b
are connected in parallel between the external electrodes
12
a
and
12
b,
and define a linear inductor
6
. The internal conductors
7
a
and
7
b
are connected in parallel between the external electrodes
13
a
and
13
b,
and define a linear inductor
7
. The internal conductors
8
a
and
8
b
are connected in parallel between the external electrodes
14
a
and
14
b,
and define a linear inductor
8
.
In the conventional lamination type inductor array
15
, the internal conductors
5
a,
5
b,
6
a,
6
b,
7
a,
7
b,
8
a,
and
8
b
have the same shape, respectively, and the shape of the inductors
5
-
8
is the same. When the external dimensions of the laminated body
10
are made smaller so that the inductor array
15
becomes small-sized, the distance d1 (see
FIGS. 10 and 11
) between the end surfaces in the length direction of the laminated body
10
and the inductors
5
and
8
located adjacent the end surface becomes smaller than the distance d2 between the inductors
5
-
8
.
Because of this fact, the cross section of the magnetic paths which are defined between the inductors
5
,
8
on the side of the end surfaces of the laminated body
10
and the end surfaces and along which the magnetic lines of force &phgr; of the inductors
5
and
8
pass, becomes smaller. Therefore, the magnetic reluctance of the magnetic paths of the inductors
5
and
8
is increased, and the inductance of the inductors
5
and
8
becomes smaller than that of the inductors
6
and
7
.
For example, the actual values at the time when the laminated body
10
has a relative magnetic permeability of 20 is shown in FIG.
13
. When the distance d1 is less than 0.5 mm, the inductance of the inductors
5
and
8
on the side of the end surfaces begins to be reduced. When the distance d1 is 0.2 mm, the inductance of the inductors
5
and
8
is about five percent smaller than that of the inner inductors
6
and
7
. When the distance d1 is 0.1 mm, the inductance of the inductors
5
,
8
is about 13 percent smaller than that of the inductors
6
,
7
. Even if the sheets
1
-
3
have a relative magnetic permeability other than 20, the result described above still occurs.
Accordingly, there is a problem with the conventional lamination type inductor array
15
in that the inductance of the inductors
5
and
8
on the side of the end surfaces varies from that of the inner inductors
6
and
7
. As a result, dispersion of the electrical characteristics such as noise elimination capability of the inductors
5
-
8
occurs because of the characteristics which are dependent on the location of the inductors inside the laminated body
10
.
SUMMARY OF THE INVENTION
To overcome the problems described above, preferred embodiments of the present invention provide a lamination type inductor array in which each of the inductors has a substantially equal inductance regardless of the location inside of the laminated body.
According to one preferred embodiment of the present invention, a lamination type inductor array includes a laminated body having insulating material layers and substantially linear internal conductors stacked on each other, a plurality of pairs of external input and output electrodes provided on a surface of the laminated body, and a plurality of inductors arranged in such a manner that both ends of each of the internal conductors are connected to the external input and output electrodes, wherein the shape of the internal conductors of the inductors located adjacent to the end surfaces of the laminated body is different from the shape of the internal conductors of the inductors disposed inside the inductors located adjacent to the end surfaces of the laminated body so that the inductance of each of the inductors is substantially equal. Based on the above construction, each of the inductors has internal conductors having a shape which is dependent on the location of the internal conductors, and the inductance of each of the inductors is substantially equal.
By making the conductor length of the internal conductors of the inductors located adjacent to the end surfaces of the laminated body longer than the conductor length of internal conductors of the inductors disposed inside of the inductors located adjacent to the end surfaces of the laminated body, the number of magnetic lines of force generated by the inductors adjacent to the end surfaces of the laminated body is increased. Because of the increased number of magnetic lines of force, any reduction in inductance caused by the decreased cross section of the magnetic path of the inductors located adjacent to the end surfaces of the laminated body is compensated so as to be negated.
Further, by arranging the internal conductors which are located adjacent to the end surfaces of the laminated body to extend in a meandering line toward the side of the inductors located inside of the inductors adjacent to the end surfaces of the laminated body, the cross section of the magnetic path of the inductors adjacent to the end surface of the laminated body is greatly increased. Because of the increased cross section, the magnetic reluctance of the magnetic path of the inductors adjacent to the end surfaces of the laminated body is suppressed.
Further, by making the conductor width of the internal conductors of the inductors disposed inside of the inductors adjacent to the end surfaces of the laminated body wider than the conductor width of the internal conductors of the inductors adjacent to the end surfaces, the cross section of the magnetic paths in which the magnetic lines of force of the inductors disposed inside of the inductors adjacent to the end surfaces of the laminated body pass is significantly reduced. Therefore, the magnetic reluctance of the magnetic paths of the inductors disposed inside is increased. Because of this increased magnetic reluctance, the inductance of the inductors located adjacent to the end surfaces of the laminated body is substantially equal to the inductance of the inductors located inside of the inductors.
Furthermore, a lamination type inductor array according to preferred embodiments of the present invention has a laminated body which is substantially rectangular parallelepiped and has inductors arranged along a longitudinal direction of the laminated body. A distance between the end surfaces in the longitudinal direction of the laminated body and the internal conductors of the inductors located adjacent to the end surfaces is preferably less than about 0.5 mm. With the above construction, it is possible to significantly reduce the size of the inductor array and to make the inductance of each of the inductors nearly equal.
For the purpose of illustrating the invention, there is

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