JPH06342702A - Voltage dependent nonlinear resistor element and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a voltage dependent nonlinear resistor different in a voltage- current curve, from the same process. CONSTITUTION:At least one kind out of bismuth oxide and lead oxide is made to exist in the state of diffusion or combination, on the interface of porcelain- electrode turning to a voltage dependent nonlinear resistor. The manufacturing method is as follows; after bismuth oxide or lead oxide is spread and baked on the surface of porcelain turning to a voltage dependent nonlinear resistor, conductive paste whose main component is metal powder glass frit is spread and baked on the above baked surface, thereby forming a metal electrode. Another method is as folows; conductive paste whose main component is metal powder glass frit and which contains bismuth oxide or lead oxide is spread and baked on the surface of the pocelain turning to the voltage dependent nonlinear resistor, thereby simultaneously performing the formation of metal electrode and the diffusion.combination of the porcelain surface of bismuth oxide or lead oxide. The conductive paste wherein bismuth oxide or lead oxide is fused in glass frit or added in the form of bismuth lead compound is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a voltage non-linear resistor element, a so-called varistor, whose resistance value is rapidly reduced by a high voltage applied, and a method of manufacturing the same. .

[0002]

2. Description of the Related Art The resistance to noise of a recent electronic device which makes heavy use of ICs that operate at low voltage and minute current has been reduced, and malfunctions due to noise are often seen. In particular, when an abnormal impulse voltage such as a high-voltage pulse or static electricity generated outside the electronic device enters the equipment, the abnormal impulse voltage may cause the electronic device to malfunction or be destroyed in the worst case. . On the contrary, a device having a contact inside the commutator motor or the like causes a spark discharge at the contact, and an impulse voltage generated by the spark discharge is radiated to the outside to invade another device such as an electronic device or malfunction or May cause adverse effects such as destruction.

In order to cope with such a problem, a voltage non-linear resistor element, which is a so-called varistor whose resistance value is rapidly decreased by voltage, is used to bypass the impulse voltage and prevent the impulse voltage from entering the electronic device. Or, the radiation of the impulse voltage to the equipment is prevented.

This varistor is disclosed in JP-A-57-2073.
No. 19, JP-A-60-206001, JP-A-61-44405, and the like, and a varistor in which a varistor layer is formed on the outside of a ceramic, and JP-B-43-2.
9500, Japanese Patent Laid-Open No. 57-27001 and the like, there is a varistor in which a varistor layer is formed at a grain boundary in a ceramic.

In these voltage non-linear resistors, electrodes are attached in order to make an electrical connection with the outside. In that case, Ag-A is used as a material for obtaining ohmic contact.
Although Cu is used as an electrode material for obtaining non-ohmic contact, an electrode material such as 1, Ag-InGa, Ag-Zn is used, but in the case of an electrode material containing only Ag as a metal powder, an electrode-porcelain interface is formed at the time of baking. Since the existence of the high resistance layer formed on the substrate causes characteristic fluctuation, it is necessary to destroy this high resistance layer by applying a pulse voltage during manufacturing.

The electrical characteristics of the voltage non-linear resistance element vary greatly depending on the type of electrode material and the forming method.
In particular, since the non-linearity which is the main electrical characteristic of the voltage non-linear resistance element is determined by the composition and treatment of the ceramic substrate, it is not possible to obtain voltage non-linear resistances with different voltage-current curves from the same process. . Therefore, it is necessary to change the manufacturing process of the ceramic substrate for each required voltage-current curve.

[0007]

SUMMARY OF THE INVENTION The present invention replaces the above-mentioned conventional voltage non-linear resistor in which the manufacturing process of the ceramic substrate has to be changed for each desired voltage-current curve.
An object of the present invention is to provide a voltage non-linear resistor and a method for manufacturing the voltage non-linear resistor that can obtain voltage non-linear resistors having different voltage-current curves from the same process.

[0008]

In order to solve the above-mentioned problems, in the present application, a non-linear resistor element in which bismuth oxide or lead oxide forms a compound with a diffusion layer or a porcelain surface at a ceramic substrate-electrode interface and its manufacture Invention of the method, that is, "voltage nonlinear resistor element characterized in that at least one kind of bismuth oxide or lead oxide is present in a diffused or combined state at the porcelain-electrode interface to be a voltage nonlinear resistor" And a bismuth oxide or lead oxide is applied and baked on the surface of the porcelain to be the voltage non-linear resistor, and then a conductive paste containing metal powder glass frit as a main component is applied and baked on the metal. Method for manufacturing voltage non-linear resistance element characterized by forming electrodes "," Metal powder glass on porcelain surface to be voltage non-linear resistance element " A non-voltage characteristic characterized by simultaneously forming and forming a metal electrode and diffusing / combining bismuth oxide or lead oxide on the porcelain surface by applying and baking a conductive paste containing lit as a main component and containing bismuth oxide or lead oxide. Method for manufacturing linear resistor element "," Bismuth oxide or lead oxide is a voltage non-linear resistor element characterized by using a conductive paste melted in glass frit or added in the form of bismuth, lead compound The manufacturing method of the invention is provided.

[0009]

In the present invention having the above structure, the voltage non-linearity of the element changes depending on the thickness of the diffusion layer and the concentration of bismuth oxide or lead oxide.

Embodiments of the present invention will be described with reference to the drawings and tables. First Embodiment FIG. 1 shows a process chart of a first embodiment of the manufacturing method of the present invention.

(1) SrTiO 3 as a ceramic substrate
₃ Ceramics are used, 1480 ℃ neutral atmosphere (N ₂ )
Firing was performed in it to obtain a ceramic.

(2) 10 each of Bi ₂ O ₃ and Pb ₃ O ₄
A first paste is obtained by dispersing 0 parts in 50 parts vehicle.

(3) Bi on the surface of the ceramic substrate
A paste obtained by dispersing 100 parts of each of ₂ O ₃ and Pb ₃ O _{4 in} 50 parts of a vehicle is applied by printing at a coating amount of 0 to 0.3 mg / cm ² .

(4) Stabilize in air at 800 ° C. to 20
Heat treatment for minutes to obtain a voltage non-linear resistance ceramic.

(5) Second, by dispersing 100 parts of Ag powder and 3 parts of glass containing ZnO as a main component in 30 parts of a vehicle.
Get the paste.

(6) The obtained second paste is applied to the surface of the voltage non-linear resistance ceramic by screen printing and dried.

(7) An Ag electrode is formed by heat treatment at 800 ° C. for 10 minutes.

Further, instead of the step of forming the Ag electrode of the first embodiment (5), (6) and (7), the step of the second embodiment of forming a Cu electrode, that is, (5 ') A second paste is obtained by dispersing 100 parts of Cu powder and 3 parts of glass containing ZnO as a main component in 30 parts of a vehicle. (6 ') The obtained second paste is applied and dried by screen printing. (7 ') C at 800 ° C in a neutral atmosphere for 10 minutes
The u electrode is formed. It is also possible to use the process of.

The coating amount of the first paste is 0.05 mg each
/ Cm ² , 0.1 mg / cm ² , 0.2 mg / cm ² , 0.3 mg /
cm ^2, and shows the varistor voltage E ₁₀ for each of the voltage nonlinear resistor samples, nonlinearity coefficient alpha, the result of measurement for the solder heat after E ₁₀ conversion and resistant pulses after E ₁₀ change rate in Table 1.

These data are obtained as follows. The varistor voltage E ₁₀ is a voltage value required to flow a current of 10 mA through the voltage nonlinear resistor. The nonlinear coefficient α is 1 / (l when the voltage value required to flow a current of 1 mA through the voltage nonlinear resistor is E _1.
ogE ₁₀ / E ₁ ). E ₁₀ rate of change after solder heat resistance is calculated by using eutectic solder with a tip temperature of 35
E ₁₀ change rate (%) after soldering at 0 ° C. for 3 seconds. The E ₁₀ change rate after the pulse resistance is the change rate (%) of E ₁₀ after the pulse voltage of 30 V and 60 V was applied.

As a comparative example, measurement results of an electrode formed by the InGa amalgam method are also shown. The results are shown in Table 1.

[Table 1]

As is clear from Table 1, sample Nos. 2 to 1
In No. 9, although Ag or Cu is used as the electrode material, the change amount of E ₁₀ is at a practical level as the coating amount of Bi ₂ O ₃ or Pb ₃ O ₄ increases.

Second Example In the second example, the particle size was 0.1 to 0.3 μm on the surface of the porcelain obtained in the step (1) under the same conditions as in the first example.
Of Cu powder of 100 parts, 3 parts of glass containing ZnO as a main component, and 0 to 5 parts of Bi ₂ O ₃ and Pb ₃ O ₄ respectively are dispersed in 30 parts of a vehicle and a paste is applied, and then a neutral atmosphere at 800 ° C. A Cu electrode was formed by heat-treating for 10 minutes.

Table 2 shows the results of the same evaluation as that of the first embodiment performed on the voltage nonlinear resistor sample of the second embodiment thus obtained.

[Table 2]

From Table 2, Bi ₂ O ₃ or P in the electrode
As shown in Table 1, the varistor voltage and α increase with increasing b ₃ O _4.
It is clear that the voltage non-linearity can be controlled by the electrode material even with the same resistor, since the increase in the voltage is observed.

[0026]

As described above, the voltage non-linear resistor element obtained by the present invention is a material which exhibits varistor characteristics even when the same ceramic substrate is used.
The voltage nonlinearity can be controlled by diffusion of i ₂ O ₃ or Pb ₃ O _{4 on} the surface of the ceramic substrate or formation of a compound. Industrially, as shown in the second embodiment, Bi ₂ O ₃ or Pb ₃ O ₄ was used as the electrode material.
The method of adding is considered to be more suitable.

[Brief description of drawings]

 1 is a process diagram of a first embodiment of the manufacturing method of the present invention.

Claims (4)

[Claims] 1. A voltage non-linear resistance element, wherein at least one kind of bismuth oxide or lead oxide is present in a state of being diffused or combined at a porcelain-electrode interface to be a voltage non-linear resistance. 2. A bismuth oxide or lead oxide is applied and baked on the surface of a porcelain which is a voltage non-linear resistor, and then a conductive paste containing metal powder glass frit as a main component is applied and baked on the porcelain to form a metal electrode. A method of manufacturing a voltage non-linear resistor element, which is characterized by being formed. 3. The formation of a metal electrode and the formation of bismuth oxide or oxidation by applying and baking a conductive paste containing metal powder glass frit as a main component and containing bismuth oxide or lead oxide on the surface of a porcelain serving as a voltage nonlinear resistor. A method of manufacturing a voltage non-linear resistance element, which comprises simultaneously diffusing and compounding a surface of lead porcelain. 4. A method of manufacturing a voltage non-linear resistor element, wherein a conductive paste in which bismuth oxide or lead oxide is melted in a glass frit or added in the form of a bismuth or lead compound is used.