JPH06244001A - Electronic components - Google Patents

Abstract

PURPOSE:To protect electronic components from characteristic changes or deteriorations induced by high voltage load generated by surges or noises intrud ing from outside by way of outside terminals of electronic components or pyroe lectric load. CONSTITUTION:Varistor powder containing ZnO, SrTiO3 or SiC, a hardening agent and a filler or the like are added to a thermosetting resin, such as epoxy resin and kneaded, thereby obtaining a sealing resin material 20 having a varistor function. An outside terminal 17 of an electronic component main body 15 is inserted into a through hole 19 of a bottom cover 14. The electronic component main body 15 is housed into a case main body 13 whose bottom is opened while the bottom opening of the case main body 13 is closed with the bottom cover 14 as well. The through hole 19 of the bottom cover 14 where the outside terminal 17 is pulled out is sealed with the sealing resin material 10 while the outside terminals 17 are electrically connected with each other with the sealing resin material 20.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to electronic components. More specifically, it relates to an electronic component in which an electronic component body is packaged in a case.

[0002]

2. Description of the Related Art There are various kinds of electronic parts such as ceramic filters, ceramic capacitors, resistor networks, and ICs, and the appearance of these electronic parts can be seen broadly. It consists of and. In addition, these electronic components are packaged in a case made of plastic, metal, or the like due to their use or design problems, and the lead-out portions of the external terminals are sealed with resin or the like. Conventionally, in these electronic components, since it is necessary to maintain insulation between external terminals, the external terminals are pulled out from the insulating part of the case and are sealed with an insulating resin or the like. It was

However, with an insulating resin such as an epoxy resin which has been conventionally used for sealing electronic parts, it is possible to prevent surges and noises that enter the electronic part body from the outside through external terminals of the electronic part. There wasn't. Also, depending on the type of electronic component, electric charge may be generated from the electronic component body itself due to temperature change or the like, such as a piezoelectric component, and a high voltage may be applied to the electronic component body. These noises, high-voltage loads, and the like have a problem that the deterioration of the electronic component body is accelerated or the characteristics of the electronic component are changed.

For example, consider the case of a ceramic filter in which an electronic component body made of piezoelectric ceramic is packaged in a plastic case. FIG. 2 is a partially cutaway perspective view showing a structure of a typical ceramic filter 1. As shown in FIG. 3 (a), the ceramic filter 1 includes a plurality of piezoelectric ceramic plates 2 having electrodes 3 on both surfaces, and a predetermined circuit configuration (for example, a ladder) formed by external terminals 4 and terminals 5 for internal connection. Type filter) to form the electronic component body 6 by connecting
The electronic component body 6 is housed in a case body 7 having a bottom surface opening, the bottom surface opening of the case body 7 is closed by a bottom lid 8, and the external terminal 4 is penetrated through the bottom lid 8 and pulled out to the outside to form an external terminal of the bottom lid 8. Portions from which 4 is drawn are sealed with a resin (not shown). The piezoelectric ceramic plate 2 is generally made of PbTiO ₃ —PbZ.
rO ₃ ceramics and the like are widely used.

When the piezoelectric ceramic plate 2 is once heated to a high temperature state [Fig. 3 (a)] and then returned to room temperature [Fig. 3 (b)], as in the case of soldering the ceramic filter 1 as described above. ] To the piezoelectric ceramic plate 2
A pyroelectric charge 9 is generated on the surface of the. This pyroelectric charge 9 produces an electric field Ep in the direction opposite to the polarization direction P of the piezoelectric ceramics plate 2 as shown in FIG. 3B, and this electric field Ep causes the degree of orientation of spontaneous polarization in the piezoelectric ceramics plate 2. Changes, and the resonance frequency and anti-resonance frequency of the ceramic filter 1 change. In order to prevent this, it is necessary to use the piezoelectric ceramic plate 2 having a small insulation resistance, and there is a drawback that there is little room for selecting a piezoelectric material.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and an object of the present invention is to provide surges or the like which enter from the outside through external terminals of electronic parts. It is to prevent characteristic changes and deterioration of electronic parts due to high voltage load generated by noise, pyroelectric charge or the like.

[0007]

The electronic component of the present invention has a varistor function in a through hole of a case in which an external terminal is inserted in an electronic component in which the body of the electronic component is housed in a case such as a plastic case or a metal case. It is characterized by being sealed by the resin material that it has.

[0008]

In the electronic component of the present invention, the through hole of the case into which the external terminal is inserted is sealed with a resin material having a varistor function. Therefore, the same effect as connecting the varistor element to the external terminal of the electronic component is obtained. Play.

That is, noise or surge that has entered from the external terminals of the electronic component can be absorbed by the sealing resin material having a varistor function, and the noise or surge can be prevented from flowing into the electronic component body. Further, even if a high voltage is generated due to pyroelectric charge or the like generated in the internal piezoelectric ceramics, if the voltage reaches the varistor voltage of the resin material having the varistor function, the resistance of the resin having the varistor function suddenly increases. Therefore, it is possible to prevent a high voltage load from being applied to the internal electronic component body due to a current flowing through the external terminal so as to cancel the electric field due to the pyroelectric charge.

On the other hand, since the sealing resin maintains the insulating property (high resistance) when a high voltage or the like is not applied, it does not impair the original function of the case.

[0011]

1 shows the structure of a ceramic filter 11 according to an embodiment of the present invention. The case 12 is composed of a plastic case body 13 and a bottom lid 14 which are open on the lower surface, and an electronic component body 15 is housed in the case 12. The electronic component body 15 is formed by alternately stacking a piezoelectric ceramics plate 16 having electrodes formed on both surfaces, an external terminal 17 and a terminal 18 for internal connection, and forming a desired circuit such as a ladder type filter. The external terminal 17 is the bottom cover 14
Through the through hole 19 of the external terminal 17
The through-hole 19 of the bottom lid 14 through which is drawn is sealed with a sealing resin material 20 having a varistor function. Moreover, the sealing resin material 20 electrically connects the external terminals 17.

Sealing resin material 2 having a varistor function
0 is, for example, Zn in thermosetting resin such as epoxy resin.
Varistor powders such as O type, SrTiO ₃ type and SiC type are kneaded and dispersed.

If the sealing resin material 20 having such a varistor function is used to seal the external terminals 17 to each other, the external terminals 1 of the electronic component body 15 are sealed.
Since the same effect as connecting a varistor element between 7 can be obtained, noise and surge that enter from the outside through the external terminal 17 of the ceramic filter 11 are absorbed by the sealing resin material 20, and The component body 15 can be protected from noise and surge.

Further, it is possible to prevent electric charges generated from the electronic component body 15 and a high voltage load due to the electric charges. For example, in the case of the ceramic filter 11 as shown in FIG. 1, the external terminals 17 are connected by the sealing resin material 20 having a varistor function, but in a normal state, the sealing resin material 20 maintains the insulating property. is doing. But,
When pyroelectric charge is generated on the surface of the piezoelectric ceramic plate 16 due to thermal shock due to soldering or the like, when the voltage due to the pyroelectric charge reaches the varistor voltage of the sealing resin material 20, the sealing resin material 20 (that is, varistor powder). The resistance is rapidly reduced, and charges are transferred through the sealing resin material 20 and the external terminals 17 so as to cancel the electric field due to the pyroelectric charge, so that the depolarization of the spontaneous polarization due to the pyroelectric charge can be prevented.

By using a resin material having a varistor function as the sealing resin material of the electronic component, the electronic component, which is the original purpose of the sealing resin material, can be sealed, and at the same time, the electronic component main body can be sealed. It is possible to prevent changes in the characteristics of the electronic component body due to loads such as noise and voltage. Moreover, the external shape of the electronic component does not become large unlike the case of connecting individual varistor elements to the electronic component, and the cost can be reduced.

Specific Examples Hereinafter, as specific examples of the present invention, a method of manufacturing a sealing resin material in which ZnO varistor powder is dispersed in a thermosetting epoxy resin will be described. Further, a ceramic filter sealed by using the sealing resin material according to this example and a ceramic filter sealed by using the sealing resin material according to the conventional example were manufactured, and resonance and anti-reflection of each ceramic filter of the example and the conventional example were manufactured. The change in resonance frequency was measured.

First, an embodiment of the present invention will be described.
As a ceramic powder having a varistor function, 9
ZnO having a purity of 9.9% or more, Sb ₂ O ₃ , Mn
A ZnO-based varistor manufactured by a so-called solid phase method using O ₂ and CoO as raw materials was used. in this case,
The firing of the raw material powder was performed at 1000 ° C to 1100 ° C.
However, at the time of firing, the raw material powder was fired as it was, then pulverized and sieved into particles having a certain particle size or less. This powder was used as a raw material varistor powder.

An epoxy resin having a thermosetting temperature of 107 ° C. was used as the thermosetting resin serving as the base resin.

Next, 80 parts by weight of varistor powder and 20 parts by weight of epoxy resin are mixed, a ketone solvent is added as a curing agent, silica is added as a filler, and a simple mixing is performed with a stirring blade. Then, a resin material for sealing was obtained. Then, this sealing resin material was kneaded with a roll.

The piezoelectric ceramic plate used for the electronic component body is (Pb _0.99 La _0.01 ) (Ti _0.50 Zr _0.50 ) O ₃ +0.2
It is made of wt% Cr ₂ O ₃ and has an electrode pattern formed by baking Ag paste or the like on the surface, and has been subjected to polarization treatment. The piezoelectric ceramic plate, the external terminals, and the terminals for internal connection were alternately arranged to form an electronic component body (ladder type filter).

The external terminals of this electronic component body were inserted into the through holes of the bottom lid, the electronic component body was housed in the case body whose bottom surface was opened, and the bottom surface opening of the case body was closed by the bottom lid to manufacture a ceramic filter. Then, the above-mentioned sealing resin material was applied to the through-holes through which the external terminals of the bottom lid were drawn out. At this time, sealing was performed so that the external terminals were connected to each other by a sealing resin material having a varistor function. Then, the resin material for sealing was cured in a 120 ° C. temperature bath.

Conventional Example On the other hand, as a conventional example, 100 parts by weight of a sealing resin material containing no varistor powder epoxy resin is prepared, and the same electronic component body as that of the embodiment is housed in the same case. The through hole was sealed under the same conditions as in the example.

Measurement Results The ceramic filter of the example thus produced and the ceramic filter of the conventional example were placed in a temperature bath of 250 ° C. for 3 minutes for heat treatment, taken out from the temperature bath, and then left at room temperature for 2 hours. did. The variation ΔFr of the resonance frequency before and after the heating and the variation ΔFa of the anti-resonance frequency at this time were examined for the example and the conventional example, respectively.
The measurement results are shown in Table 1.

[0024]

[Table 1]

As can be seen from Table 1, according to the present embodiment, the resonance
Both the frequency changes ΔFr and ΔFa of the anti-resonance frequency could be made extremely small.

Although the above-mentioned embodiment shows the case where the invention is applied to a ceramic filter, the present invention can be applied to all electronic parts sealed with a sealing resin material. For example, when used for a ceramic capacitor, by sealing with a sealing resin material having a varistor function, the internal capacitor body can be protected even if noise having a voltage higher than the withstand voltage occurs. As for various other types of electronic components, it is needless to say that the electronic component body can be protected from surges and noises by using a sealing resin material having a varistor function. Also, instead of electrically connecting the external terminals with the sealing resin material that seals the lead-out portion of the external terminals, you can prevent surges by contacting the sealing resin material with the ground part, etc. can do.

[0027]

According to the present invention, in an electronic component in which an electronic component main body is housed in a plastic or metal case, the lead-out portion of the external terminal is sealed by a sealing resin material having a varistor function. It is possible to obtain a multifunctional electronic component having both the original function of the electronic component and the function of the varistor.

Therefore, it is possible to protect the electronic component from noise and surge by absorbing the noise and surge coming from the outside through the external terminals of the electronic component by the resin material for sealing. Further, it is possible to remove electric charges such as pyroelectric charges generated from the electronic component main body and a high voltage load due to the electric charges through the resin material for sealing.

Therefore, the life of the electronic component can be remarkably extended. In addition, it is possible to prevent the characteristics of the electronic component body from changing or deteriorating due to a load such as noise.
Furthermore, since the electronic component body can be protected from noise, high voltage load, etc. by the sealing resin material having the varistor function, there is an advantage that the range of selection of the material used for the electronic component body can be widened.

[Brief description of drawings]

FIG. 1 is a sectional view showing a ceramic filter according to an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view showing a conventional ceramic filter.

3 (a) and 3 (b) are explanatory views showing a mechanism of generating a pyroelectric charge on a piezoelectric ceramic plate.

[Explanation of symbols]

 11 Ceramic Filter 12 Case 13 Case Body 14 Bottom Lid 16 Piezoelectric Ceramics Plate 17 External Terminal 19 Through Hole 20 Resin Material for Sealing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunobu Yoneda 2 26-10 Tenjin Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. An electronic component in which an electronic component body is housed in a case such as a plastic case or a metal case, wherein a through hole of the case into which an external terminal is inserted is sealed with a resin material having a varistor function. Electronic components.