JPH1069961A - surge absorber - Google Patents

Abstract

(57) Abstract: The present invention relates to a surge absorber that absorbs a surge voltage applied to an electronic device, which can be easily mounted on a surface, has high reliability against repeated discharge, and has a low cost. Provide a surge absorber with a built-in capacitor. SOLUTION: A first electrode 2, a conductive film 5 having a micro gap 3, and a second electrode 3 are formed concentrically on a flat insulating substrate 1, and a multilayer substrate is formed inside the substrate 1. The conductor films 13 and 14 constituting the capacitor are arranged by using the technique described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surge absorber for absorbing a surge voltage applied to an electronic device.

[0002]

2. Description of the Related Art Conventionally, there has been known a surge absorber which is used for protecting an electronic device and absorbs a surge voltage applied to the electronic device. For example,
In Japanese Patent No. 57918, a conductive ceramic thin film is formed on the surface of a cylindrical insulating material, and a microgap is formed in a circumferential direction so as to divide the conductive ceramic thin film. A surge absorber having a structure sealed in a cylindrical glass in a closed state is disclosed. Also, Japanese Patent Publication No. 7-107867, Shokai 4
Japanese Patent Application Laid-Open No. 9-80351 proposes a surge absorber in which a spire electrode having a pointed tip toward a microgap is formed on a flat insulating substrate.

[0003]

However, among the surge absorbers proposed in the prior art, those having a structure sealed in a cylindrical glass have a cylindrical outer shape and lead wires extend from both ends of the cylinder. There is a problem that surface mounting and automatic mounting are difficult. In addition, since this structure has a cylindrical outer shape, it is difficult to use a material other than glass as an airtight covering material.

[0004] Among the conventionally proposed surge absorbers, those having a structure in which an electrode and a microgap are formed on a flat plate have a spire shape in the electrode in the microgap portion. There is a problem that the tip of the spire electrode is easily damaged, and the life to repeated discharge is short. In addition, this type of surge absorber cannot remove high-frequency noise having a small voltage and high frequency.When it is necessary to remove high-frequency noise, a surge absorber is used in combination with a high-frequency removal capacitor. In this case, it is necessary to mount a capacitor separately from the surge absorber, which causes problems such as an increase in mounting area and mounting cost. In order to solve this problem, a surge absorber having a built-in capacitor has been proposed (Japanese Patent Laid-Open No. 8-8367).
0, JP-A-8-83691, JP-A-8-1
No. 02355), these surge absorbers have an original structure that is complicated regardless of whether a capacitor is incorporated or not, and further increasing the cost by incorporating the capacitor leads to a demand for cost reduction. Not satisfied.

In view of the above circumstances, an object of the present invention is to provide a surge absorber with a built-in capacitor which can be easily mounted on a surface, has high reliability against repetitive discharges, and is reduced in cost.

[0006]

A surge absorber according to the present invention that achieves the above object has the following features. (1) A flat insulating substrate (2) An annular gap is formed on an insulating substrate and is concentric with the gap. (3) a first electrode disposed at the center of the conductive film; and (4) an annular ring disposed at the periphery of the conductive film and concentric with the gap. Second electrode (5) In cooperation with the insulating substrate, an airtight covering material (6) that seals the conductive film, the first electrode, and the second electrode in a state where a predetermined gas is filled therein. A) a first terminal disposed outside the hermetic crown material and electrically connected to the first electrode; and (7) a second terminal disposed outside the hermetic crown material is electrically connected to the first electrode. (8) Spread parallel to each other and at least one of the second terminals has the insulating property. Composed of a plurality of conductive films extending in the interior of the plate,
A capacitor is provided between the first terminal and the second terminal.

Here, in the surge absorber of the present invention, the area of a portion where a plurality of conductive films constituting the capacitor overlap and the interval between the conductive films are determined so that a capacitance suitable for noise to be removed can be obtained. Is selected. When a large capacitance is required, the capacitance can be increased by increasing the number of conductive film layers constituting the capacitor.

As a material of the multilayer substrate having a conductor film formed therein, a glass ceramic which can be fired at a low temperature is desirable, and its dielectric constant is determined from the viewpoint of how much capacitor is required. . In the surge absorber of the present invention, since the first electrode, the second electrode, the conductive film, and the micro gap are all disposed on the same plane on the flat insulating substrate, the outer shape can be easily formed into a flat plate. And surface mounting is easy.

Further, since the outer shape can be easily made into a flat plate shape, a ceramic material such as alumina can be used as the material of the hermetic capping material. Furthermore, in the surge absorber according to the present invention, the first electrode, the second electrode, the conductive film, and the micro gap are all formed on the same plane and are formed concentrically. Discharge occurs uniformly, and even if a part of the conductive film is lost due to the discharge, the discharge starting voltage is hardly changed, and the reliability for repeated discharge is high.

In addition, since the surge absorber of the present invention has a built-in capacitor, high frequency noise having a small voltage and a high frequency can be removed. The conductor film that forms the capacitor for removing high-frequency noise is formed inside or on the back of the insulating substrate, so mounting the capacitor for removing high-frequency noise on the surge absorber increases the size of the element and increases the mounting area. No problem. This capacitor for removing high-frequency noise can be formed by using a conventional method for manufacturing a multilayer substrate, and cost can be reduced.

Since the basic structure and principle of the surge absorber of the present invention are the same as those disclosed in Japanese Patent Publication No. 63-57918, the surge absorber of the present invention is disclosed in The excellent surge absorption characteristics and high reliability possessed by the same are directly followed.

[0012]

Embodiments of the present invention will be described below. FIGS. 1 to 3 show a first embodiment of a surge absorber according to the present invention. FIG. 1 is a perspective view showing the internal structure of a cap with a part of the cap broken away, FIG. FIG. 2 is a cross-sectional view as viewed in a direction indicated by an arrow AA in FIG.

As shown in FIG. 3, a multi-layer substrate 1 having conductor films 13, 14 and through holes 11 formed therein as shown in FIG.
And a conductor film 1 on the front and back surfaces of the substrate 1, respectively.
0, 12 are formed, first and second terminals 8, 9 are formed on the side surface of the substrate 1, and Ti is formed as a conductive film 5 on the surface of the substrate 1.
After N is deposited by sputtering, a circular microgap 3 having a width of about 50 μm is formed by photoetching.
Is formed, the conductive film 5 is formed into a desired circular shape, and the first electrode 2 and the second electrode 4 are mounted concentrically with the micro gap 3 so as to be in contact with the conductive film 5.

Further, the micro gap 3 is sealed in Ar gas by welding a cap 6 made of alumina ceramic with frit glass 7. The first electrode 2 and the conductor film 14 inside the substrate 1 are connected to each other by a through hole 11 provided in the substrate 1, and further connected to the first terminal 8 by a conductor film 12 on the back surface of the substrate 1.

The conductor film 13 formed inside the substrate 1
Has a hole in the part where the through hole 11 penetrates,
Further, a portion is exposed to the end face of the substrate on the side of the second terminal 9 to be connected to the second terminal 9, and this and the conductive film 10 are connected to the second electrode 4. This realizes a surge absorber that has a flat outer shape, is suitable for surface mounting, has high reliability against repeated discharges, and absorbs high-frequency noise.

FIG. 4 shows a second embodiment of the surge absorber of the present invention.
It is a sectional view of an embodiment. Here, as the insulating substrate, a conductive film 1 is formed inside by a conventionally known technique.
7 and 18, a conductive film 10 and a conductive film 12 are formed on the front and back surfaces of the substrate 15, respectively, and the side surfaces of the substrate 1 are formed in the same manner as in the first embodiment. After forming the first and second terminals 8 and 9 and depositing TiN as a conductive film 5 on the substrate 1 by sputtering, a circular microgap 3 having a width of about 50 μm is formed by photoetching and the conductive film 5 is formed. The first electrode 2 and the second electrode 4 are formed in a desired circular shape, and the conductive film 5 is formed concentrically with the micro gap 3.
Attach to

Further, the cap 6 made of alumina ceramic is welded with frit glass 7 to seal the micro gap 3 in Ar gas. First electrode 2
The conductive film 18 inside the substrate 1 is connected to each other by a via hole 16 provided in the substrate 1.
Is connected to the first terminal 8 by exposing a part of the substrate to the end face of the substrate on the first terminal 8 side.

The conductor film 17 formed inside the substrate 1
Is connected to the second terminal 9 by being partially exposed to the end face of the substrate on the side of the second terminal 9, and is connected to the second electrode 4 by this and the conductor film 10. As described above, also in the second embodiment, as in the first embodiment, a surge absorber that has a flat outer shape, is suitable for surface mounting, has high reliability against repeated discharge, and also absorbs high-frequency noise is realized. I do.

In each of the above embodiments, two conductor films constituting the capacitor are formed inside the substrate, but one of those two films is formed on the back surface of the substrate. You may. Further, in each of the above-described embodiments, the capacitor has two conductive films, but when a large-capacity capacitor is required, the capacitor may be configured with three or more conductive films.

[0020]

As described above, according to the present invention,
A surge absorber with a flat outer shape, easy surface mounting, and a concentric arrangement achieves a highly reliable surge absorber against repeated discharges. Further, according to the present invention, at least one capacitor including a plurality of conductive films formed inside the substrate is built in, and high-frequency noise is also removed. This capacitor can be formed by a conventional method of manufacturing a multilayer substrate, and low cost is achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an internal structure of a surge absorber according to a first embodiment of the present invention with a cap partially cut away.

FIG. 2 is a plan view of the surge absorber according to the first embodiment of the present invention as seen through a cap.

FIG. 3 is a cross-sectional view of the surge absorber according to the first embodiment of the present invention, as viewed in a direction indicated by arrows AA in FIGS. 1 and 2;

FIG. 4 is a sectional view of a second embodiment of the surge absorber according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 first electrode 3 micro gap 4 second electrode 5 conductive film 6 cap 7 frit glass 8 first terminal 9 second terminal 10 conductive film 11 through hole 12, 13, 14 conductive film 15 multilayer substrate 16 Via holes 17, 18 Conductive film

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[Procedure amendment]

[Submission date] September 30, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

FIG. 4 shows a second embodiment of the surge absorber of the present invention.
It is a sectional view of an embodiment. Here, as the insulating substrate, a conductive film 1 is formed inside by a conventionally known technique.
7, 18, using a multi-layer substrate 15 via hole 16 is formed, similarly to the first embodiment described above, respectively to form a conductive film 10 and the conductor film 12 on the front and back surfaces of the substrate 15, the side surface of the substrate 15 After forming the first and second terminals 8 and 9 and depositing TiN as a conductive film 5 on the substrate 15 by sputtering, a circular microgap 3 having a width of about 50 μm is formed by photoetching and the conductive film 5 is formed. The first electrode 2 and the second electrode 4 are formed in a desired circular shape, and are attached to the conductive film 5 concentrically with the micro gap 3.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

Further, the cap 6 made of alumina ceramic is welded with frit glass 7 to seal the micro gap 3 in Ar gas. First electrode 2
A substrate 15 inside the conductive film 18 are connected to each other by via holes 16 provided in the substrate 15, the first terminal 8 by further part of the conductor film 18 is exposed to the substrate end face of the first terminal 8 side It is connected to the.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

The conductor film 1 formed inside the substrate 15
7 is connected to the second terminal 9 by being partially exposed to the end face of the substrate on the side of the second terminal 9.
Are connected to the second electrode 4. in this way,
In the second embodiment, as in the first embodiment, a surge absorber that has a flat outer shape, is suitable for surface mounting, has high reliability against repeated discharge, and absorbs high-frequency noise is also realized.

Claims (1)

[Claims] 1. A flat insulating substrate, a conductive film having a circular gap formed on the insulating substrate and formed concentrically with the gap, and a central portion of the conductive film A first electrode disposed; an annular second electrode disposed at a peripheral portion of the conductive film and forming a concentric circle with the gap; and cooperating with the insulating substrate, the conductive film, A hermetic capping member for sealing the first electrode and the second electrode in a state in which a predetermined gas is filled therein; and a first electrode disposed outside the hermetic capping material. A first terminal electrically connected; a second terminal disposed outside the hermetic capping material and electrically connected to the second electrode; A first conductive film extending in the insulating substrate and extending in parallel with each other; Surge absorber, characterized in that a capacitor formed between the child second terminal.