Laminate type varistor

Details Laminate type varistor Laminate type varistor

1998-12-18

2002-02-12

Easthom, Karl D. (Department: 2832)

Electrical resistors

Resistance value responsive to a condition

Current and/or voltage

C338S020000, C338S204000, C338S314000

Reexamination Certificate

active

06346871

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a laminate type varistor adapted for being incorporated into a small-capacitance high-frequency circuit, or the like.
2. Description of the Related Art
Conventionally, as shown in
FIG. 5
, a laminate type varistor is configured in the following manner. That is, at least two inner electrodes
20
a
and
20
b
making a pair to each other and a varistor layer
21
are laminated. Ceramic layers
22
and
23
are provided as outermost layers for protecting the laminate. The inner electrodes
20
a
and
20
b
are electrically connected to outer electrodes
24
and
25
respectively. The varistor layer
21
has a dielectric constant. The inner electrodes
20
a
and
20
b
are formed to have surfaces W facing each other through the varistor layer
22
(Unexamined Japanese Patent Publication (kokai) Nos. Hei. 5-6806 and Hei. 5-6807).
Similarly, conventionally, also in the case where pairs of inner electrodes
30
a,
30
b;
31
a,
31
b;
. . . are provided in a laminate type varistor as shown in FIG.
6
. The laminate type varistor is configured in the following manner. That is, the inner electrodes
30
a,
30
b;
31
a,
31
b;
. . . are formed so that the inner electrodes have surfaces W facing each other through varistor layers
32
a,
32
b
. . . respectively. Protection ceramic layers
33
and
34
are provided as outermost layers. The inner electrodes
30
a,
30
b;
31
a,
31
b;
. . . are electrically connected to outer electrodes
35
and
36
respectively (Unexamined Japanese Patent Publication (kokai) Nos. Hei. 5-283208 and Hei. 8-55710).
In the laminate type varistor configured as described above, the capacitance increases as the facing surfaces W of the inner electrodes
20
a,
20
b,
30
a,
30
b,
31
a,
31
b
. . . increase in terms of areas. However, if the capacitance is large, a high-frequency signal may be passed through the varistor or the waveform of the signal may be distorted in the case where the varistor is used in a high-frequency circuit. To prevent this problem, it is necessary to set the capacitance to a value of about several tens of pF. In the aforementioned configuration, however, it is difficult to set the capacitance to a value of about several tens of Pf.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a laminate type varistor in which capacitance can be set to a small value while a varistor voltage is kept in a value equivalent to that of a conventional varistor.
A laminate type varistor according to the present invention comprises at least one pair of first and second inner electrodes; a varistor layer, the at least one pair of first and second electrodes and the varistor layer being laminated; and a first outer electrode and a second outer electrode electrically connected to the first inner electrode and a second inner electrode, respectively, wherein the first inner electrode and the first inner electrode are separated by a predetermined distance from the outer electrode so that the first inner electrode has no electrode surface facing to an electrode surface of the second inner electrode.
A laminate type varistor according to the present invention comprises: a ceramic sintered body comprising at least one pair of first and second inner electrodes; a varistor layer, the at least one pair of first and second electrodes and the varistor layer being laminated; and protection ceramic layers as outermost layers of the ceramic sintered body; and a first outer electrode and a second outer electrode electrically connected to the first inner electrode and a second inner electrode, respectively; wherein a width of the ceramic sintered body is equal to or longer than the sum of the lengths of the first and second inner electrodes.


REFERENCES:
patent: 4729058 (1988-03-01), Gupta et al.
patent: 5034709 (1991-07-01), Azumi et al.
patent: 5155464 (1992-10-01), Cowman et al.
patent: 5245309 (1993-09-01), Kawase et al.
patent: 5324986 (1994-06-01), Ueno et al.
patent: 6008717 (1999-12-01), Kawase et al.
patent: 6087923 (2000-07-01), Ahn et al.
patent: 5-6806 (1993-01-01), None
patent: 5-6807 (1993-01-01), None
patent: 5-283208 (1993-10-01), None
patent: 6-13206 (1994-01-01), None
patent: 7235406 (1995-09-01), None
patent: 8-55710 (1996-02-01), None
U.S. application No. 09/017,229, filed Feb. 2, 1998.
U.S. application No. 09/215,134, filed Dec. 18, 1998.
Patent Abstracts of Japan, vol. 017, No. 261 (E-1369), May 21, 1993, JP 05 006806, Jan. 14, 1993.

Affiliated with

Also associated with

Rating

Laminate type varistor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Laminate type varistor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laminate type varistor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2962163