JPH07176408A - Voltage-dependent nonlinear resistor ceramic element - Google Patents

Abstract

PURPOSE:To provide a voltage dependent nonlinear resistor ceramic element which has high reliability without change in electric characteristics even if part of solder enters between a pin and the element in the element having capacitor characteristics and varistor characteristics to be used to protect a semiconductor and a circuit of an apparatus against an abnormally high voltage, noise, static electricity generated in electric and electronic apparatuses. CONSTITUTION:Semiconductor ceramics containing SrTiO3 as a main ingredient are formed in a multi-stage cylindrical shape of a protruding section having a through hole at a center in such a manner that a length of a cylindrical part having a large diameter is less than 1/2 of the length of the entirety as an element 13. An inner peripheral electrode 11 is formed on an inner periphery of the hole of the element 13 and an outer peripheral element 12 is formed on an outer periphery except both ends. Thus, since the inner periphery of the cylindrical shape is integrated as one electrode (inner peripheral electrode 11), even if conductive adhesive such as solder, etc., enters a gap between a pin and the element 13, an apparent distance between the electrodes is not varied. Further, since a connection to an external terminal is facilitated and an adhesive strength can be increased, excellent electric characteristics and reliability are obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage dependency having a capacitor characteristic and a varistor characteristic used for the purpose of protecting semiconductors and circuits of equipment from abnormally high voltage, noise and static electricity generated in electric equipment and electronic equipment. The present invention relates to a non-linear resistor ceramic element.

[0002]

2. Description of the Related Art Conventionally, SiC having a voltage-dependent non-linear resistance characteristic for absorbing abnormal high voltage, eliminating noise, eliminating sparks, and preventing static electricity in various electric and electronic devices.
Varistors and ZnO-based varistor are used.
The voltage-current characteristic of such a varistor can be approximately expressed by the following equation.

[0003]

[Equation 1]

Here, I is a current, V is a voltage, C is a constant unique to a varistor, and α is a voltage-current nonlinear index.

Α of a SiC varistor is about 2 to 7, ZnO
In some system varistors, α is as high as 50. Although such a varistor has excellent performance in absorbing a relatively high voltage, it has almost no effect in absorbing a relatively low voltage below the varistor voltage due to its low dielectric constant and small intrinsic capacitance. Is not shown, and the dielectric loss tan δ is 5 to 10%.
It was a big one.

On the other hand, in removing these low-voltage noises, the apparent dielectric constant is about 5 × 10 ⁴ , and tan δ is 1.
% Semiconductor capacitors are used. But,
When a voltage or current exceeding a certain limit is applied to such a semiconductor capacitor due to a surge or the like, the electrostatic capacitance is reduced or destroyed, and the semiconductor capacitor does not function as a capacitor.

Therefore, recently, a material containing SrTiO ₃ as a main component and having both functions of varistor characteristics and capacitor characteristics has been developed, and semiconductor elements and circuits such as ICs and LSIs in electronic devices such as computers are protected and electronically protected. It is used to remove noise that enters from cables and connectors that connect devices to each other.

FIG. 7 shows the structure of an element having the above-mentioned element having the functions of both a varistor and a capacitor mainly composed of SrTiO ₃ and used for removing noise that enters from a connector or the like. In FIG. 7, 1 and 2 are electrodes and 3 is S
It is an element composed of a semiconductor ceramic having rTiO ₃ as a main component and having a voltage-dependent nonlinear resistance characteristic. When such an element is incorporated into a connector, it is generally as shown in FIG. In FIG. 8, 4 is a pin, 5 and 6 are solders as a conductive connecting member, and 7 is a common terminal.

[0009]

However, in the above-mentioned conventional structure, when the same element is assembled in the connector as shown in FIG. 8, a part of the solder 5 flows into the gap between the pin 4 and the element 3 and apparently appears. There is a drawback that the distance between the electrodes is reduced, the varistor voltage is lowered, the varistor voltage is polarized, and the insulation resistance is lowered.

The present invention solves the above problems and provides an element having a structure in which the varistor voltage does not change even if a part of the solder flows into the gap between the pin and the element, the varistor voltage has no polarity, and the insulation resistance does not change. It is intended to be provided.

[0011]

In order to solve the above-mentioned problems, the voltage-dependent nonlinear resistor ceramic element according to the present invention is composed of SrTiO _{3 as} a main component and has a convex cross-section with a through hole in the center. A semiconductor ceramic having a multi-stage cylindrical shape and a large-diameter cylindrical portion whose length is less than 1/2 of the entire length has an inner peripheral electrode on the inner peripheral surface of the through hole and an outer periphery excluding both end surfaces. The outer peripheral electrode is formed on the surface.

[0012]

With this structure, since the inner peripheral electrode is integrated as one electrode, even if a conductive adhesive such as solder flows into the gap between the pin and the element, it is on the integrated electrode and apparently The distance between the electrodes does not change. Therefore, the electrical characteristics are stable, the varistor voltage does not change, the varistor voltage has no polarity, and the insulation resistance does not change.

Further, when the outer peripheral electrode is connected to the common terminal with a conductive adhesive such as solder, the connection is easy and the adhesive strength is increased, and excess conductive adhesive such as solder is dripped into the multi-stage cylindrical shape. It is possible to prevent the apparent distance between the electrodes from changing by stopping at the plane portion of the multi-stage boundary portion of. Even if the conductive adhesive such as solder sags, it sags in the direction away from the outer peripheral electrode, so the apparent distance between the electrodes does not change.

Further, by providing the outer peripheral electrode also on the above-mentioned plane portion, when the common terminal is connected by a conductive adhesive or the like, the contact area becomes large, the connection is easy, and the connection can be made from two directions. The adhesion between the common terminal and the element can be increased, the mechanical strength can be improved, and the deterioration of characteristics due to the temperature cycle test can be reduced, and the reliability can be improved. .

If the uppermost layers of the inner and outer peripheral electrodes and the common terminal are plated with solder, for example, the gap between the pin and the inner peripheral electrode and the gap between the outer peripheral electrode and the common terminal can be made small, a conductive adhesive can be obtained. Even without the above, the inner peripheral electrode, the outer peripheral electrode, and the solder plating of the uppermost layer of the common terminal can be melted and connected to each other only by performing the heat treatment.

In order to sufficiently bring out the electrical characteristics of the device, one or more kinds of Cu plating, Ni plating, Cr plating, Sn plating, Pb plating, Au plating, Ag plating, Pd plating, and solder plating are used. By overlapping the plating of the above, the electrical characteristics of the element can be fully brought out without forming a barrier at the interface between the element and the electrode, and it can be easily soldered to form multiple types of multilayer plating structures. By doing so, the solder heat resistance can be further improved.

[0017]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be specifically described.

SrCO ₃ , CaCO ₃ , BaCO ₃ , Mg
CO ₃ and TiO ₂ were weighed at various composition ratios as shown in (Table 1) and (Table 2) below, and then weighed with a ball mill or the like.
Mix for 0 hours. Next, after being dried, it is baked at 1075 ° C. for 3 hours, pulverized again by a ball mill for 20 hours, and then dried to obtain the first component.

[0019]

[Table 1]

[0020]

[Table 2]

Next, the first component, the second component and the third component were weighed so as to have the composition ratios shown in (Table 1) and (Table 2), mixed for 24 hours with a ball mill or the like, and then dried. 10% organic binder such as polyvinyl alcohol
After adding wt% and granulating, the press pressure is 1 ton / cm ² and the small outer diameter part of the multi-stage cylinder shown in FIG.
4 mm in height and 2.5 mm in height, large outer diameter part is 6 mm in outer diameter and 0.5 mm in height, and the through hole has an inner diameter of 1.4 mm in a multi-stage cylindrical shape and fired in air at 1150 ° C for 5 hours. Remove the binder.

Next, a reducing atmosphere such as N ₂ : H ₂ =
Bake for 5 hours at 1400 ° C. in 9: 1 gas. After that, at 4 ° C at 1105 ° C in an oxidizing atmosphere such as air.
Bake for hours. A conductive ohmic paste made of Zn or the like is formed on the inner peripheral surface of the through hole and the outer peripheral surface excluding both end surfaces of the thus obtained sintered body by a method such as roller transfer.

After that, it is dried at 120 ° C. for 10 minutes, and then a non-ohmic conductive paste is similarly provided thereon by a method such as roller transfer, and at 120 ° C. for 1 minute.
Drying for 0 minutes and baking at 650 ° C. for 10 minutes to form an inner peripheral electrode and an outer peripheral electrode, and the device thus obtained is shown in FIG.

In FIG. 1, 11 is an inner peripheral electrode provided on the entire inner peripheral surface of the multi-stage cylindrical through hole, 12 is an outer peripheral electrode provided on the entire outer peripheral surface excluding both end surfaces of the multi-stage cylindrical shape, and 13 is SrTiO 3. It is an element made of a semiconductor ceramic having a voltage-dependent nonlinear resistance characteristic of ₃ as a main component, and a cylindrical through hole is formed in the central part of a multistage cylindrical shape.

FIG. 2 shows a state in which the voltage-dependent nonlinear resistor ceramic element 13 according to the present invention is incorporated in a connector. In FIG. 2, 14 and 15 are conductive connecting members such as solder and conductive adhesive, 16 is a pin, 17 is a common terminal, 18
Indicates a case.

As described above, according to the present invention, the inner peripheral electrode 11 formed in the multi-stepped cylindrical through hole is integrated as one electrode, so that conductive adhesive such as solder is attached to the gap between the pin 16 and the element 13. Even if the agent 14 flows in, the apparent inter-electrode distance does not change because it is on the integrated inner peripheral electrode 11.

Therefore, the electrical characteristics are stable, the varistor voltage does not change, the varistor voltage has no polarity, and the insulation resistance does not change. In addition, since the outer peripheral electrodes 12 are provided on the outer peripheral surfaces of the multi-stage cylindrical shape excluding both end surfaces, when connecting the common terminal 17 with the conductive adhesive 15 or the like, the flat surface portion of the stepped portion can be used and the contact can be made. Since the area to be used is large and the connection is easy, and since the common terminal 17 can be connected from two directions, the adhesive force between the common terminal 17 and the element 13 can be increased, and the mechanical strength can be improved. In addition, the deterioration of characteristics due to the temperature cycle test can be reduced, and the reliability can be improved.

Further, a conductive adhesive 15 such as extra solder is used.
It is possible to prevent the apparent distance between the electrodes from changing by stopping the sagging in the above plane. Even if the conductive adhesive 15 such as solder sags, it will sag in a direction away from the outer peripheral electrode 12, so that the apparent inter-electrode distance does not change. Further, by providing the flat surface portion, the surface insulation distance can be widened, the electrical characteristics are stable, the varistor voltage does not change, the varistor voltage does not have polarity, and the insulation resistance does not change. Even when assembled into a connector, the effect that the change in the characteristics before and after the assembly is extremely small and stable can be obtained, and it is possible to improve the life span characteristics and improve the reliability.

(Example 2) After obtaining a fired body in the same manner as in Example 1, a conductive ohmic layer made of Zn or the like is formed on the inner peripheral surface of the through hole of the sintered body and the outer peripheral surface excluding both end surfaces. After forming the pastes by a method such as roller transfer, the pastes are dried at 120 ° C. for 10 minutes and baked at 630 ° C. for 3 minutes.

Next, the conductive portion is activated by a weak acid or the like, and only the portion activated by electroless is Cu-plated-N.
i-plating is performed, and electrolytic solder plating is further applied thereon to form a three-layer structure to form the inner peripheral electrode 11 and the outer peripheral electrode 12. Next, as shown in FIG. 2, the pins 16 and the common terminal 17 are attached by using conductive connecting members 14 and 15 such as solder, filled with a resin such as butadiene rubber, and cured by heating. The characteristics of the element 13 obtained in this way are compared with those of the element 1
Table 3 and Table 4 show the three individual components and the assembled connector.

[0031]

[Table 3]

[0032]

[Table 4]

It should be noted, V _1mA is the voltage applied across the element 13 to that which causes 1mA current, the polarity of V _1mA in a difference in the positive direction of V _1mA and the negative direction of the V _1mA in the positive direction of V _1mA The insulation resistance is the insulation resistance value between the pin 16 and the common terminal 17 when the applied voltage is 12 VDC. Also,
The evaluation of the temperature cycle test is shown by the change rate of V _1mA after 500 cycles at -20 to 85 ° C.

As described above, in the present embodiment, the uppermost layer of the inner peripheral electrode 11, the outer peripheral electrode 12 and the common terminal 17 is solder-plated so that, for example, the gap between the pin 16 and the inner peripheral electrode 11 or the outer peripheral electrode 12 and the common terminal is formed. If the gap of 17 is made small, the inner peripheral electrode 11 and the outer peripheral electrode 12 and the common terminal 17 can be processed by heat treatment without the conductive adhesives 14 and 15.
The uppermost layer of the solder plating melts each other to make a connection.

Further, in order to bring out the electrical characteristics of the element 13 sufficiently, Cu plating, Ni plating, Cr plating, S
n plating, Pb plating, Au plating, Ag plating, Pd
By arranging one or more kinds of plating among plating and solder plating, the electric characteristics of the element 13 can be sufficiently obtained without forming a barrier at the interface between the element 13 and the electrode. It can be easily soldered, and the solder heat resistance can be improved by using a plurality of types of multilayer plating structures. Further, by making the shape of the element 13 a multistage cylindrical shape, the length of the element 13 becomes long,
Since the size of the element 13 can be reduced in the radial direction, the distance between the pins 16 of the connector can be reduced, which is extremely effective for downsizing the connector, and the effect of the present invention is extremely large.

In the above embodiment, the first component Sr
Although only a part of the ratio of substituting Ca, Ba, and Mg for a part of the above is shown, it does not matter as long as it is within the range of having the varistor characteristic and the capacitor characteristic at the same time as the characteristics of the element 13. . Further, the ratio of A site and B site is shown only for equimolar amounts, but it may be A site rich or B site rich, and if the ratio is within the range of having both varistor characteristics and capacitor characteristics as the characteristics of the element 13. It doesn't matter what it is. Further, the second component and the third component are shown only for some combinations in the embodiment, but any component may be used as long as it is within the range of simultaneously having the varistor characteristic and the capacitor characteristic as the characteristics of the element 13. . Further, as the ohmic electrode, there are Ag, Cu, Ni, etc. in addition to Zn, but any other electrode may be used as long as ohmic connection can be made at the interface between the element 13 and the electrode. . The plating method may be electrolytic or electroless, and may be acid plating, basic plating or neutral plating.

Further, the voltage-dependent nonlinear resistor porcelain element 13 according to the present invention may be connected to an inductance composed of, for example, a ferrite, a coil or a toroidal coil to improve the noise removing effect.

(Embodiment 3) A third embodiment of the present invention will be specifically described below.

SrCO ₃ , CaCO ₃ , BaCO ₃ , Mg
CO ₃ and TiO ₂ are weighed at various composition ratios as shown in (Table 5) below and mixed for 24 hours with a ball mill or the like. Next, after being dried, it is baked at 1050 ° C. for 4 hours, pulverized again by a ball mill or the like for 24 hours, and then dried to obtain the first component.

[0040]

[Table 5]

[0041]

[Table 6]

Next, the first component, the second component and the third component were weighed so as to have the composition ratios shown in (Table 5) and (Table 6), mixed with a ball mill for 24 hours and then dried. 10% organic binder such as polyvinyl alcohol
After adding wt% and granulating, the press pressure is 1 ton / cm ² , and the small outer diameter part of the multi-stage cylinder shown in FIG.
4 mm in height and 2.5 mm in height, large outer diameter part is 6 mm in outer diameter and 0.5 mm in height, and the inner diameter of the through hole is 1.4 mm in a multi-stage cylindrical shape and fired in air at 1200 ° C for 10 hours. Remove the binder.

Next, a reducing atmosphere such as N ₂ : H ₂ =
Bake for 5 hours at 1425 ° C. in 9: 1 gas. After that, at 5 ° C. at 1120 ° C. in an oxidizing atmosphere such as air.
Bake for hours. The conductive ohmic paste made of Zn or the like is applied to the inner peripheral surface of the through hole of the sintered body thus obtained and the outer peripheral surface excluding a fixed distance from both end surfaces and the end portion on the cylindrical portion side having a large diameter, such as roller transfer. Are formed by the above method.

After that, it is dried at 120 ° C. for 10 minutes, and a non-ohmic conductive paste is similarly provided thereon by a method such as roller transfer, and at 120 ° C. for 1 minute.
It is dried for 0 minutes and baked at 630 ° C. for 3 minutes to form the inner peripheral electrode 21 and the outer peripheral electrode 22, and the element thus obtained is shown in FIG.

In FIG. 3, reference numeral 21 denotes an inner peripheral electrode provided on the entire inner peripheral surface of the multi-stepped cylindrical through hole, and reference numeral 22 denotes a fixed distance from both end surfaces of the multi-stepped cylindrical shape and the end on the side of the large diameter cylindrical portion. Except for the outer peripheral electrodes provided on the entire outer peripheral surface, 23 is Sr
It is an element made of a semiconductor ceramic having TiO ₃ as a main component and having voltage-dependent non-linear resistance characteristics, and a cylindrical through hole is formed in the central portion of a multistage cylindrical shape.

FIG. 4 shows a state in which the voltage-dependent nonlinear resistor ceramic element 23 according to the present invention is incorporated in a connector. In FIG. 4, 14 and 15 are conductive connecting members such as solder and conductive adhesive, 16 is a pin, 17 is a common terminal, 18
Indicates a case.

The voltage-dependent non-linear resistance ceramic element 23 of the present invention having the above-described structure has the same effect as that of the element 13 described in the first embodiment.
Detailed description is omitted.

(Embodiment 4) After obtaining a fired body in the same manner as in the above-mentioned Embodiment 3, a constant amount is obtained from the inner peripheral surface of the through hole of this sintered body, both end surfaces and the end portion on the cylindrical portion side having a large diameter. An ohmic conductive paste of Zn or the like is formed on the outer peripheral surface excluding the distance by, for example, a method such as roller transfer, and after providing an electrode, it is dried at 120 ° C. for 10 minutes and baked at 630 ° C. for 3 minutes. Next, the conductive portion is activated by a weak acid or the like, and only the portion activated by electroless is Cu-plated-N.
The i-plating is performed, and the electroplating is further performed by solder plating to form a three-layer structure to form the inner peripheral electrode 21 and the outer peripheral electrode 22.

Next, as shown in FIG. 4, the pins 16 and the common terminal 17 are attached by conductive connecting members 14 and 15 such as solder, and resin such as butadiene rubber is filled.
Heat cure. The characteristics of the element 23 obtained in this way are shown after the element 23 is singly assembled with the connector (Table 7).
And (Table 8).

[0050]

[Table 7]

[0051]

[Table 8]

[0052] Incidentally, V _1mA is the voltage applied across the element 23 when the flow of 1mA current, the polarity of V _1mA in a difference in the positive direction of V _1mA and the negative direction of the V _1mA in the positive direction of V _1mA The insulation resistance is the insulation resistance value between the pin 16 and the common terminal 17 when the applied voltage is 12 VDC. Also,
The evaluation of the temperature cycle test is shown by the change rate of V _1mA after 500 cycles at -20 to 85 ° C.

The voltage-dependent non-linear resistance ceramic element 23 of the present invention having the above-described structure has the same effect as that of the element 13 described in the second embodiment.
Detailed description is omitted.

In the above-described embodiments, the ratio of substituting a part of Sr of the first component with Ca, Ba and Mg was shown only in the embodiments, but the characteristics of the element 23 are varistor characteristics. Any capacitor may be used as long as it has a capacitor characteristic at the same time. Furthermore, A
Although the ratio of sites and B sites is shown only for equimolar amounts, it may be A site-rich or B site-rich, and the ratio may be any as long as the voltage-dependent nonlinear resistance characteristic is obtained. . The second component and the third component are shown only for some combinations in the embodiments, but any component may be used as long as it is within the range of simultaneously having the varistor characteristic and the capacitor characteristic as the characteristics of the element 23.

As the ohmic electrode, there are Ag, Cu, Ni, etc. in addition to Zn. Any other electrode can be used as long as ohmic connection can be made at the interface between the element 23 and the electrode. I don't care. Moreover, although only a part of the components to be plated and the combination thereof are shown, the components and combinations other than these are not limited to these as long as the same effect can be obtained. The plating method may be electrolytic or electroless, acidic plating, basic plating or neutral plating.

Further, the voltage-dependent nonlinear resistor porcelain element 23
A noise removing effect can be improved by adopting a configuration in which an inductance including a ferrite, a coil, a toroidal coil, or the like is connected to the above.

(Fifth Embodiment) Hereinafter, a fifth embodiment of the present invention will be described in detail.

SrCO ₃ , CaCO ₃ , BaCO ₃ , Mg
CO ₃ and TiO ₂ are weighed at various composition ratios as shown in (Table 9) below, and mixed for 20 hours with a ball mill or the like. Next, after being dried, it is baked at 1050 ° C. for 4 hours, pulverized again by a ball mill or the like for 24 hours, and then dried to obtain the first component.

[0059]

[Table 9]

[0060]

[Table 10]

Next, the first component, the second component, and the third component were weighed so as to have the composition ratios shown in (Table 9) and (Table 10), mixed with a ball mill for 30 hours, and then dried. 10% organic binder such as polyvinyl alcohol
After adding wt% and granulating, the small outer diameter part of the multi-stage cylindrical shape shown in FIG. 5 has an outer diameter of φ4 with a press pressure of 1 ton / cm ² .
mm in height 2.5 mm, large outer diameter part is 6 mm in outer diameter and 0.5 mm in height, and the inner diameter of the through hole is 1.4 mm in a multi-stage cylindrical shape and fired in air at 1100 ° C for 6 hours. Remove the binder. Next, a reducing atmosphere, for example N ₂ : H ₂ = 9:
Baking for 4 hours at 1375 ° C. in the gas of 1. Further, thereafter, firing is performed at 1105 ° C. for 4 hours in an oxidizing atmosphere, for example, air.

Inner peripheral surface of the through hole of the sintered body thus obtained
And from both end surfaces and the end surface on the side of the cylinder with a small diameter
The conductive outer surface made of Zn or the like is formed on the entire outer peripheral surface excluding the distance.
Mick paste by a method such as roller transfer
Set up. Then, dry at 120 ° C for 10 minutes, and then
Apply non-ohmic conductive paste from above
Provided by a method such as roller transfer, at 120 ° C for 10 minutes
And dry for 5 minutes at 550 ° C.
1. The peripheral electrode 32 is formed, and the element thus obtained is
The offspring are shown in FIG. In FIG. 5, 31 is a multi-stage cylindrical through
Inner electrode provided on the entire inner surface of the hole, 32 is a multi-stage cylinder
Constant from both ends of the shape and the end of the small diameter cylinder
The outer peripheral electrodes 33 provided on the entire outer peripheral surface excluding the distance,
SrTiO ₃-Dependent Non-Linear Resistance Characteristic Consisting of
Is an element made of semiconductor ceramic having
A cylindrical through hole is formed at the center of the cylinder.

FIG. 6 shows a state in which the voltage-dependent nonlinear resistor porcelain element 33 according to the present invention is incorporated in a connector. 6, 14 and 15 are conductive connecting members such as solder and conductive adhesive, 16 is a pin, 17 is a common terminal, 18
Indicates a case.

The voltage-dependent nonlinear resistance porcelain element 33 of the present invention having the above-described structure has the same effect as that of the element 13 described in the first embodiment.
Detailed description is omitted.

(Example 6) After obtaining a fired body in the same manner as in the above-mentioned Example 5, the inner peripheral surface of the through hole of this sintered body, both end surfaces, and the end portion on the side of the cylindrical portion having a small diameter are fixed. A conductive ohmic paste made of Zn or the like is formed on the entire outer peripheral surface excluding the distance by, for example, a method such as roller transfer, and after providing an electrode, it is dried at 120 ° C. for 10 minutes, and 600
Bake at ℃ for 7 minutes.

Next, the conductive portion is activated by a weak acid or the like, and only the portion activated by electroless is Cu-plated-N.
i plating, and then electrolytic solder plating on it,
An inner peripheral electrode 31 and an outer peripheral electrode 32 are formed in a three-layer structure. Next, as shown in FIG. 6, the pins 16 and the common terminal 17 are attached by the conductive connecting members 14 and 15 such as solder, and the resin such as butadiene rubber is filled and heat-cured. The characteristics of the element 33 thus obtained are compared with those of the element 3
It shows in (Table 11) and (Table 12) after assembling 3 single parts and a connector.

[0067]

[Table 11]

[0068]

[Table 12]

[0069] Incidentally, V _1mA is the voltage applied across the element 33 when the flow of 1mA current, the polarity of V _1mA in a difference in the positive direction of V _1mA and the negative direction of the V _1mA in the positive direction of V _1mA The insulation resistance is the insulation resistance value between the pin 16 and the common terminal 17 when the applied voltage is 12 VDC. Also,
The evaluation of the temperature cycle test is shown by the change rate of V _1mA after 500 cycles at -20 to 85 ° C.

The voltage-dependent nonlinear resistor porcelain element 33 of the present invention having the above-mentioned structure has the same effect as that of the element 13 described in the second embodiment.
Detailed description is omitted.

In the above-mentioned embodiments, the ratio of substituting a part of Sr of the first component with Ca, Ba, and Mg was shown only in the embodiments, but the characteristics of the element 33 are varistor characteristics. Any capacitor may be used as long as it has a capacitor characteristic at the same time. Furthermore, A
Although the ratios of sites and B sites are shown only for equimolar amounts, they may be A site rich or B site rich, and the ratio may be any as long as it has both varistor characteristics and capacitor characteristics. Further, the second component and the third component are shown only for some combinations in the embodiment, but any component may be used as long as it is within the range of simultaneously having the varistor characteristic and the capacitor characteristic as the characteristics of the element 33.

As the ohmic electrode, there are Ag, Cu, Ni, etc. in addition to Zn. Any other electrode can be used as long as ohmic connection can be made at the interface between the element 33 and the electrode. I don't care. Further, only a part of the components to be plated and the combination thereof are shown, but the components and combinations other than these are not limited to these as long as the same effect can be obtained. The plating method may be electrolytic or electroless, acidic plating, basic plating or neutral plating. Further, the voltage-dependent nonlinear resistor porcelain element 33 is connected to an inductance such as a ferrite, a coil, a toroidal coil or the like to improve the noise removing effect.

[0073]

As described above, in the voltage-dependent nonlinear resistor porcelain element according to the present invention, the inner peripheral electrode formed in the multi-stage cylindrical through hole is integrated as one electrode, so that the gap between the pin and the element is increased. Even if a conductive adhesive such as solder flows in, the apparent distance between the electrodes does not change because it is on the integrated inner peripheral electrodes.

Therefore, the electrical characteristics are stable, the varistor voltage does not change, the varistor voltage has no polarity, and the insulation resistance does not change.

Also, a constant distance is removed from the entire outer peripheral surface excluding both end surfaces of the multi-stage cylindrical shape or from both end surfaces and the end portion on the side of the large diameter cylindrical portion or the end portion on the side of the small diameter cylindrical portion. Since the outer peripheral electrode is provided on the entire outer peripheral surface, the flat surface of the stepped portion can be used when connecting the common terminal with a conductive adhesive, etc., and the contact area becomes large, and the connection is easy and common. Since the terminals can be connected from the upper and lower sides, the adhesive force between the common terminal and the element can be increased, the mechanical strength can be improved, and the deterioration of the characteristics due to the temperature cycle test can be reduced. Therefore, the reliability can be improved.

Further, by stopping the sagging of the conductive adhesive such as extra solder at the flat surface portion, the apparent distance between the electrodes can be kept unchanged. Even if the conductive adhesive such as solder sags, it sags in the direction away from the outer peripheral electrode, so the apparent distance between the electrodes does not change. Further, by providing the above flat portion,
The surface insulation distance can be wide, the electrical characteristics are stable, the varistor voltage does not change, the varistor voltage has no polarity, the insulation resistance does not change, and the characteristics change before and after assembly even when the element is assembled into the connector. Has an effect of being extremely small and stable, and it is possible to improve the life characteristics of voltage application and reliability.

If the uppermost layers of the inner and outer peripheral electrodes and the common terminal are plated with solder, for example, the gap between the pin and the inner peripheral electrode and the gap between the outer peripheral electrode and the common terminal can be reduced, the conductive adhesive Even without the above, the inner peripheral electrode, the outer peripheral electrode, and the solder plating of the uppermost layer of the common terminal can be melted and connected to each other only by performing the heat treatment.

Further, in order to sufficiently bring out the electrical characteristics of the element, Cu plating, Ni plating, Cr plating, Sn
By forming one or more kinds of plating among plating, Pb plating, Au plating, Ag plating, Pd plating, and solder plating, it is possible to electrically connect the elements without forming a barrier at the interface between the elements and the electrodes. It is possible to bring out the desired characteristics sufficiently, it is possible to easily solder, and it is possible to improve the heat resistance of the solder by using a plurality of types of multilayer plating structures. In addition, although the length of the element is increased by making the shape of the element into a multi-stage cylindrical shape, the dimension of the element can be reduced in the radial direction, so that the pin interval of the connector can be reduced and the connector can be miniaturized. Many effects such as being extremely effective are obtained, and the practical effects according to the present invention are extremely large.

[Brief description of drawings]

FIG. 1 is a sectional view showing a voltage-dependent nonlinear resistor ceramic element according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the same element of FIG. 1 assembled into a connector.

FIG. 3 is a sectional view showing a voltage-dependent nonlinear resistor porcelain element according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of the same element of FIG. 3 assembled into a connector.

FIG. 5 is a sectional view showing a voltage-dependent nonlinear resistor ceramic element according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of the same element of FIG. 5 assembled into a connector.

FIG. 7 is a cross-sectional view showing a conventional voltage-dependent nonlinear resistor ceramic element.

8 is a cross-sectional view of the same element of FIG. 7 assembled into a connector.

[Explanation of symbols]

 11 Inner peripheral electrode 12 Outer peripheral electrode 13 Element 14, 15 Conductive connection member 16 Pin 17 Common terminal 18 Case 21 Inner peripheral electrode 22 Outer peripheral electrode 23 Element 31 Inner peripheral electrode 32 Outer peripheral electrode 33 Element

Claims (7)

[Claims] 1. A multi-stage cylindrical shape having a convex cross-section with a through hole in the center, the main component of which is SrTiO ₃ , and the length of the large-diameter cylindrical portion is less than 1/2 of the entire length. A voltage-dependent nonlinear resistor porcelain element having an inner peripheral electrode formed on the inner peripheral surface of the through hole and an outer peripheral electrode formed on the outer peripheral surface excluding both end surfaces of the formed semiconductor ceramic element. 2. The outer peripheral electrode is formed by providing an electrodeless portion for a certain distance from the end on either the end on the side of the large diameter cylindrical portion or the end on the side of the small diameter cylindrical portion. The voltage-dependent nonlinear resistor ceramic element according to claim 1. 3. The voltage-dependent nonlinear resistor porcelain element according to claim 1 or 2, wherein the inner peripheral electrode and the outer peripheral electrode are ohmic electrodes as a base and non-ohmic electrodes are laminated on the upper layer. . 4. An inner peripheral electrode, an outer peripheral electrode is an ohmic electrode as a base, and the upper layer is plated with Cu, Ni, Cr, Sn, Pb, Au, Ag, Pd, or solder. The method according to claim 1 or 2, wherein one or a plurality of types of plating are stacked.
The voltage-dependent nonlinear resistor porcelain element described. 5. The inner peripheral electrode and the outer peripheral electrode are overlaid with one or more kinds of platings of Cu plating, Ni plating, Cr plating, Sn plating, Pb plating, Au plating, Ag plating, Pd plating, and solder plating. The voltage-dependent nonlinear resistor porcelain element according to claim 1 or 2, which is a 6. The voltage-dependent nonlinear resistor porcelain element according to claim 1 or 2, wherein the uppermost layers of the inner and outer electrodes are solder plated. 7. The voltage-dependent nonlinear resistor porcelain element according to claim 1 or 2, wherein a part of Sr as a main component is replaced with at least one element of Ca, Ba and Mg.