JP3208899B2 - Electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component. More specifically, the present invention relates to an electronic component in which an electronic component is packaged in a case.

[0002]

2. Description of the Related Art There are a wide variety of electronic components, such as filters, oscillators, discriminators, traps, and the like. These electronic components are generally composed of an electronic component body and external terminals. Have been. Many of these electronic components are packaged in various cases made of plastic, metal, or the like due to their use or design problems, and the lead portions of the external terminals are sealed with resin or the like. Conventionally, in these electronic components, it is necessary to maintain insulation between the external terminals. Therefore, the external terminals are drawn out from the insulating portion of the case to the outside, and are sealed with an insulating resin or the like. Was.

However, in the case of an insulating resin such as an epoxy resin which has been conventionally used for sealing electronic components, electric charges are generated from the electronic component main body due to a temperature change or the like, a high voltage is applied to the electronic component main body, and the electronic component main body is applied. It was not possible to prevent problems such as accelerating the deterioration of the device and changing the characteristics. In particular, when the electronic component body is made of piezoelectric ceramics, pyroelectric charges are generated by a high-temperature load during soldering, and there is a problem that the characteristics are degraded due to polarization depolarization.

[0004] For example, consider a case of a ceramic filter in which an electronic component whose main body is made of piezoelectric ceramics is packaged in a plastic case. FIG. 2 is a partially broken perspective view showing the structure of a typical ceramic filter 1. In this ceramic filter 1, a plurality of piezoelectric ceramic plates 2 having electrodes 3 arranged on both sides are connected by an external terminal 4 and an internal connection terminal 5 so as to form a predetermined circuit configuration (for example, a ladder filter). The electronic component body 6 is housed in a case body 7 having a lower surface opening, the lower surface opening of the case body 7 is closed by a bottom cover 8, and the external terminals 4 are penetrated through the bottom cover 8 to form an external component. And the portions of the bottom cover 8 from which the external terminals 4 are drawn out are sealed with resin (not shown). The piezoelectric ceramic plate 2 has
Generally, PbTiO ₃ -PbZrO ₃ ceramics and the like are widely used.

[0005] In such a ceramic filter 1, as in the case of soldering, the piezoelectric ceramic plate 2
Is once brought to a high temperature state, the spontaneous polarization of the piezoelectric ceramic plate 2 becomes small due to the high temperature load, and FIG.
The state shown in FIG. 3A changes from the state shown in FIG. 3B to the state shown in FIG. 3B, and pyroelectric charges 9 (charges generated on the crystal surface due to a temperature change in spontaneous polarization) are generated on the surface of the piezoelectric ceramic plate 2.
As shown in FIG. 3B, the pyroelectric charges 9 generate an electric field Edp that depolarizes the polarization P of the piezoelectric ceramic plate 2, and the electric field Edp changes the degree of orientation in the piezoelectric ceramic plate 2. And ceramic filter 1
However, there is a disadvantage that the frequency characteristics change. In order to prevent this, a piezoelectric ceramic plate 2 having a small insulation resistance must be used, and there is a problem that there is less room for selecting a piezoelectric material.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has as its object to prevent a characteristic change or deterioration of electronic components due to a high voltage load generated by pyroelectric charges or the like. It is in.

According to the electronic component of the present invention, in an electronic component in which the electronic component body is housed in a case such as a plastic case or a metal case, the through hole of the case into which the external terminal is inserted is sealed with a resin material having a sudden change thermistor function. It is characterized by doing.

[0008]

According to the electronic component of the present invention, a sudden change thermistor (hereinafter, abbreviated as CTR) in which the resistance value suddenly decreases at a certain temperature through a through hole of a case into which an external terminal is inserted.
Since the sealing is performed with the resin material having the function, the same effect as when the CTR element is connected to the external terminal of the electronic component can be obtained.

That is, even when a high-temperature load is applied to the electronic component body by soldering or the like, when the temperature reaches the critical temperature of the sealing resin material, the resistance of the resin portion having the CTR function rapidly decreases. Even if pyroelectric charges are generated on the surface of the piezoelectric ceramic due to the pyroelectric charges, if the temperature drops again, it is discharged through the resin part in the low-resistance state, and the electric field due to the pyroelectric charges can be eliminated. It is possible to prevent a high voltage load from being applied to the electronic component body. Also, when using a CTR, the resistance of the resin decreases more rapidly than when using an NTC thermistor, so that the electric field due to the pyroelectric charge can be canceled immediately, and the high voltage load is effectively prevented from being applied. Can be.

On the other hand, the sealing resin maintains insulation (high resistance) when a high voltage or the like is not applied, so that the original function of the case is not impaired.

[0011]

FIG. 1 shows a structure of a ceramic filter 11 according to an embodiment of the present invention. The case 12 includes a plastic case body 13 and a bottom cover 14 that are open at the bottom, and an electronic component body 15 is housed in the case 12. The electronic component body 15 is configured by alternately stacking a piezoelectric ceramic plate 16 having electrodes formed on both sides, an external terminal 17 and an internal connection terminal 18 to form a desired circuit such as a ladder filter. The external terminals 17 are drawn out from the through holes 19 of the bottom cover 14, and the through holes 19 of the bottom cover 14 from which the external terminals 17 are drawn are electrically connected between the external terminals 17 by a sealing resin material 20 having a CTR function. Connected.

A sealing resin material 20 having a CTR function
For example, CTR is applied to thermosetting resin such as epoxy resin.
The powder is kneaded and dispersed.

If the external terminals 17 are sealed by, for example, connecting the external terminals 17 with a sealing resin material having such a CTR function, it is the same as connecting a CTR element between the external terminals 17 of the electronic component body 15. Therefore, it is possible to prevent charges generated from the electronic component body 15 and a high voltage load due to the charges. For example, FIG.
In the case of the ceramic filter 11 as shown in FIG. 1, between the external terminals 17 is a sealing resin material 20 having a CTR function.
However, in a normal state, the sealing resin material 20 retains the insulating property and fulfills the purpose of the original sealing resin. However, when the temperature of the electrode surface rises due to soldering and the surface temperature reaches the critical temperature of the CTR, the sealing resin material 20 (that is,
When the spontaneous polarization is restored again due to the temperature drop, the pyroelectric charge generated on the surface by the thermal shock due to the soldering is reduced by the low-resistance sealing resin material 20 and the external terminals. 17 and the like, the generation of the electric field Edp due to the pyroelectric charge can be prevented, and the depolarization of spontaneous polarization due to the pyroelectric charge can be prevented.

[0014] By using a resin material having a CTR function as the sealing resin material for the electronic component as described above, the sealing of the electronic component, which is the original purpose of the sealing resin material, can be performed, and at the same time, the sealing of the electronic component body can be performed. A change in characteristics of the electronic component body due to a load such as a voltage can be prevented. Moreover, unlike the case where individual CTR elements are connected to the electronic component, the outer shape of the electronic component does not increase, and the cost can be reduced.

Specific Examples Hereinafter, as specific examples of the present invention, V ₇₅ Ge ₁₀ P ₅
A method for producing a sealing resin material in which a CTR powder having a composition of Sr ₁₀ O _x is dispersed in a thermosetting epoxy resin,
A ceramic filter sealed using the sealing resin material will be described. Further, a ceramic filter sealed by using a sealing resin material according to the conventional example was manufactured, and changes in the resonance frequency and the anti-resonance frequency of each of the ceramic filters of the example and the conventional example were measured.

First, an embodiment of the present invention will be described.
CTR powders having a CTR function include V ₂ O ₅ , (NH ₄ ) ₂ HPO ₄ , SrCO ₃ , and G having a purity of 99.9% or more.
eO was used as starting material. These raw materials are weighed and mixed in a predetermined ratio, melted red-hot in a porcelain crucible, poured into water to form glass-like flakes, heat-treated in a weak reducing atmosphere at 200 to 300 ° C., crushed again, and crushed. The particles were sieved to those having a particle size equal to or less than the particle size. This powder was used as a raw material CTR powder (V ₇₅ Ge ₁₀ P ₅ Sr ₁₀ O _x ).

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 the CTR powder and 20 parts by weight of the epoxy resin are mixed, a ketone solvent is added as a curing agent, and silica is added as a filler, and simple mixing is carried out with a stirring blade. A resin material for sealing was obtained.
Thereafter, the sealing resin material was kneaded with a roll.

The piezoelectric ceramic plate used for the electronic component body is made of (Pb _0.99 La _0.01 ) (Ti _0.50 Zr _0.50 ) O ₃ +0.2 wt% Cr ₂ O ₃ , and has an electrode formed by baking an Ag paste on the surface. A pattern is formed and polarization processing is performed.
An electronic component body (ladder-type filter) was formed by alternately arranging the piezoelectric ceramic plate, external terminals, and internal connection terminals.

The external terminals of the electronic component main body were inserted into the through holes of the bottom cover, and the electronic component main body was housed in the case main body with the lower surface opened, and the lower surface opening of the case main body was closed with the bottom lid to produce a ceramic filter. Then, the above-mentioned resin material for sealing was applied to the through hole from which the external terminal of the bottom cover was 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 CTR function. Thereafter, the sealing resin material was cured in a 120 ° C. temperature bath.

Conventional Example On the other hand, as a conventional example, a sealing resin material of 100 parts by weight of an epoxy resin containing no CTR powder was prepared, and the external terminals of a ceramic filter in which the same electronic component body as in the embodiment was housed in the same case were pulled out. The through hole was sealed under the same conditions as in the example.

Measurement Results The ceramic filter of the embodiment and the ceramic filter of the prior art thus prepared were placed in a 250 ° C. temperature bath for 3 minutes to perform a heat treatment, taken out of the temperature bath, and left at room temperature for 2 hours. did. At this time, the change amount ΔFr of the resonance frequency and the change amount ΔFa of the antiresonance frequency before and after heating were examined for the example and the conventional example, respectively.
Table 1 shows the measurement results.

[0023]

[Table 1]

As can be seen from Table 1, according to the present embodiment, the resonance of the ceramic filter is smaller than that of the conventional example.
Both the frequency change amounts ΔFr and ΔFa of the anti-resonance frequency could be made very small.

Although the above embodiment shows a case where the present invention is applied to a ceramic filter, the present invention can be used for all electronic parts sealed with a sealing resin material. For example, when used for a ceramic oscillator,
By sealing with a sealing resin material having a CTR function, fluctuations in the oscillation frequency can be prevented even after a high-temperature load such as soldering. For various other types of electronic components, the use of a sealing resin material having a CTR function can, of course, prevent the electronic component body from being deteriorated in characteristics after a high-temperature load.

In addition, even if a piezoelectric material has been conventionally used but cannot be used due to its insulation resistance being too high even if it has excellent piezoelectric characteristics, it can be reduced by a high temperature load by sealing with a sealing resin material having a CTR function. Poles can be prevented.

[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, a lead portion of an external terminal is sealed with a sealing resin material having a CTR function. It is possible to obtain a multifunctional electronic component having both the original function of the component and the function of the CTR.

Thus, charges such as pyroelectric charges generated from the electronic component main body and a high-voltage load due to the charges can be removed by the sealing resin material.

Therefore, the life of the electronic component can be significantly extended. In addition, since the electronic component main body can be protected from a high voltage load or the like by the resin material having the CTR function, there is an advantage that the range of choice of the material used for the electronic component main body can be expanded.

[Brief description of the drawings]

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

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

FIGS. 3A and 3B are explanatory diagrams showing a mechanism of generating a pyroelectric charge on a piezoelectric ceramic plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Ceramic filter 12 Case 13 Case main body 14 Bottom cover 16 Piezoelectric ceramic plate 17 External terminal 19 Through hole 20 Resin material for sealing

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Tachibana ▲ Taka ▼ Toshihiko 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Murata Manufacturing Co., Ltd. (56) References JP-A-3-49271 (JP, A) JP-A-1-96548 (JP, A) JP-A-57-95766 (JP, U) JP-A-1-270301 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 5/00-5/06 H03H 9/02

Claims (1)

(57) [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 a case through which an external terminal is inserted is sealed with a resin material having a sudden change thermistor function. Electronic components.