JPH0963804A - Resistor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resistor which is hardly affected by external factors and excellent in productivity, and a manufacturing method of the resistor. SOLUTION: A first, a second, and a third metal oxide covering films 2, 3, 4 are formed, in this order, on the surface of an insulating substrate 1. Resistivity of the second metal oxide covering film 3 is smaller than that of the first metal oxide covering film 2. Resistivity of the first metal oxide covering film 2 is equal to that of the third metal oxide covering film 4, or resistivity of the third metal oxide covering film 4 is larger than that of the first metal oxide covering film 2. Thereby, a resistor which is hardly affected by external factors and excellent in productivity, and a manufacturing method of the resistor are obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor having a three-layer metal oxide film and a method for manufacturing the same.

[0002]

2. Description of the Related Art A conventional technique will be described below.

As a prior art, Japanese Patent Laid-Open No. 23860/1990
No. 2, “A metal oxide film has a first metal oxide film in direct contact with the surface of an insulating substrate, and a first metal oxide film coated on the first metal oxide film and having a specific resistance larger than that of the first metal oxide film. Two
And a third metal oxide film having a smaller specific resistance than the second metal oxide film, which is further coated on the second metal oxide film. ing.

Further, in Japanese Patent Laid-Open No. 2-253601, "A metal oxide film is a first metal oxide film which is in direct contact with the surface of an insulating substrate, and a first metal oxide film is coated on the first metal oxide film. A second metal oxide film having a specific resistance smaller than that of the metal oxide film, and further coated on the second metal oxide film,
A three-layer metal oxide film comprising a third metal oxide film having a smaller specific resistance than the first metal oxide film and a specific resistance different from that of the second metal oxide film is disclosed.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In No. 38602, since the third metal oxide film has a smaller specific resistance than the second metal oxide film, there is a problem that the third metal oxide film exhibiting the main resistance characteristic is susceptible to external factors such as moisture. Was there.

Further, in the above-mentioned Japanese Patent Application Laid-Open No. 2-253601, the second and third metal oxide films have a smaller specific resistance than the first metal oxide film, and therefore the second and third metal oxide films exhibiting a main resistance characteristic.
The third metal oxide film has a problem that it is susceptible to external factors such as moisture.

Further, in both of the conventional manufacturing methods described above, the resistance liquid is sprayed directly onto the insulating substrate, so that the liquid is deposited on the entire device heating the insulating base material, resulting in a large loss of the resistance liquid. Had.

The present invention solves the above-mentioned conventional problems, and provides a resistor which is less affected by external factors and is excellent in mass productivity, and a method of manufacturing the same.

[0009]

In order to solve the above conventional problems, the structure of the present invention has an insulating base, a first metal oxide film provided on the surface of the insulating base, and a first oxide. A second metal oxide film having a specific resistance value smaller than that of the first metal oxide film on the surface of the metal film, and a second metal oxide film having a specific resistance value equal to that of the first metal oxide film on the surface of the second metal oxide film. The metal oxide film of No. 3 is provided.

Further, the structure of the present invention is such that an insulating substrate, a first metal oxide film provided on the surface of the insulating substrate, and a surface of the first metal oxide film which is higher than that of the first metal oxide film. A second metal oxide film having a small resistance value and a third metal oxide film having a larger specific resistance value than the first metal oxide film are provided on the surface of the second metal oxide film.

Further, according to the manufacturing method of the present invention, the heated insulating substrate is passed through a smoke-like first resistance film gas to form a first metal oxide film on the surface of the insulating substrate. And heating the insulating substrate having the metal oxide film formed thereon to pass through a second resistance film gas to form a second metal oxide film, and heating the insulating substrate having the second metal oxide film formed thereon. Then, a step of forming a third metal oxide film by passing through the gas of the third resistance film is provided.

[0012]

With the above structure, the influence of external factors is less likely to occur.

Further, the above manufacturing method is excellent in mass productivity.

[0014]

【Example】

(Embodiment 1) Hereinafter, a resistor according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a resistor according to an embodiment of the present invention. In the figure, 1 is a columnar insulating substrate,
It is a porcelain substrate whose main component is alumina. Reference numeral 2 is a first metal oxide film containing tin oxide as a main component provided on the surface of the insulating substrate 1, and is provided so as to prevent deterioration of characteristics of other metal oxide films described later due to an alkali component generated from the insulating substrate 1. It is a thing. The second metal oxide film 3 is provided on the surface of the first metal oxide film 2 and has a smaller specific resistance than the first metal oxide film 2 and exhibits main resistance characteristics. The second metal oxide film 3 contains tin oxide as a main component and contains at least antimony / iron.・ Vanadium ・ Chrome ・
It contains at least one of nickel, molybdenum, manganese, copper, zinc, bismuth, cobalt, and indium, and preferably contains antimony.
Reference numeral 4 denotes a third oxide provided on the surface of the second metal oxide film 3, which has the same specific resistance as that of the first metal oxide film 2 and is provided so as to prevent characteristic deterioration of the second metal oxide film 3. A metal film containing tin oxide as a main component. Reference numeral 5 is a metal cap provided on each end of the insulating substrate 1 provided with the first, second and third metal oxide films 2, 3 and 4.
Reference numeral 6 is a lead wire provided so as to be electrically connected to the metal cap 5. Reference numeral 7 is a protective film provided so as to cover at least the metal cap 5 and the third metal oxide film 4.

Regarding the resistor configured as described above,
The manufacturing method will be described below.

First, the insulating substrate 1 is heated to about 700 ° C. in an electric furnace.
Heat to. Next, the insulating substrate 1 is passed through the first metal oxide film gas in which high temperature air is sent while vaporizing the resistance liquid containing tin chloride / methanol and hydrochloric acid as main components, and the surface of the insulating substrate 1 is passed. First metal oxide film 2
Formed and cooled at room temperature.

Next, the insulating substrate 1 having the first metal oxide film 2 formed on its surface is heated to about 700 ° C., and a solution of tin chloride, methanol and hydrochloric acid is added to antimony, iron, vanadium, chromium, nickel, molybdenum.・ Manganese ・ Copper ・
This first metal oxide is passed through the insulating substrate 1 into a second acid-gold gas formed by sending in high temperature air while vaporizing a resistance liquid containing at least one of zinc, bismuth, cobalt and indium. A second metal oxide film 3 is formed on the surface of the film 2 and cooled at room temperature. At this time, the second resistance film gas forming the second metal oxide film 3 has a concentration
Either the composition or the temperature is different.

Next, the first and second metal oxide films 2 are formed on the surface.
Insulating substrate into the third resistance film gas in which high-temperature air is sent while heating insulating substrate 1 on which 3 is formed to about 700 ° C. and vaporizing the resistance liquid containing tin chloride / methanol and hydrochloric acid as main components 1 is passed to form a third metal oxide film 4 on the surface of the second metal oxide film 3 and cooled at room temperature. At this time, a third metal oxide film 4 forming a third
The resistance film gas of is the concentration / composition of the first resistance film gas.
One of the temperatures is the same, and one of them is different from the second resistance gas.

Next, after the metal caps 5 are press-fitted into both ends of the insulating substrate 1 having the first, second, and third metal oxide films 2, 3, and 4 formed on their surfaces, each of the metal caps 5 is pressed. The lead wire 6 is welded so as to be electrically connected to.

Finally, at least the third metal oxide film 4
The protective film 7 is formed by coating so that the resistor is manufactured.

(Second Embodiment) A resistor according to another embodiment of the present invention will be described below. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description will be omitted.

The structure differs from that of the first embodiment in that a third metal oxide film 4 having a larger specific resistance than that of the first metal oxide film 2 is provided on the surface of the second metal oxide film 3. Is.

The manufacturing method of the first embodiment is different from that of the first metal oxide film 3 in that the third metal oxide film 4 is formed on the surface of the second metal oxide film 3 by using a resistance liquid having a larger specific resistance than that of the first metal oxide film 2. The difference is in the point of formation.

(Comparative Example) A comparative example in which the conventional example and the embodiment of the present invention are compared will be described below.

As an experimental method, the protective film was removed from the resistor described in the prior art or the present invention, and a mist-like water droplet was sprayed while applying a constant voltage for a certain period of time and then left for 10 minutes. Was measured.

FIG. 2 is a diagram showing the relationship between time and resistance change rate in comparison with the conventional example and the embodiment of the present invention. As is clear from FIG. 2, the resistor of the present invention has a low rate of change in resistance value even if the water droplet spraying time is longer than that of the conventional resistor. Therefore, a resistor that is stable against external factors and has a long life is required. It is provided.

In this embodiment, the resistor which does not have the resistance value modified has been described, but the same effect can be obtained by modifying the resistance value of the third metal oxide film with a laser as necessary.

[0029]

As described above, the present invention can provide a resistor which is hardly affected by external factors such as water droplets which affect the characteristic change of the resistor.

Further, by using the smoke method, it is possible to provide a method for manufacturing a resistor which is excellent in mass productivity and inexpensive.

[Brief description of drawings]

FIG. 1 is a sectional view of a resistor according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between time and a resistance change rate in comparison with a conventional example and an example of the present invention.

[Explanation of symbols]

 1 Insulating Substrate 2 First Metal Oxide Film 3 Second Metal Oxide Film 4 Third Metal Oxide Film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shindo ▲ Yasu ▼ Hiro 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yasuhiko Yokota 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. In the company

Claims (11)

[Claims] 1. An insulating substrate, a first metal oxide film provided on the surface of the insulating substrate, and a second metal oxide film having a specific resistance value smaller than that of the first metal oxide film on the surface of the first metal oxide film.
And a third metal oxide film having a specific resistance value equal to that of the first metal oxide film on the surface of the second metal oxide film. 2. An insulating substrate, a first metal oxide film provided on the surface of the insulating substrate, and a second metal oxide film having a specific resistance value smaller than that of the first metal oxide film on the surface of the first metal oxide film.
And a third metal oxide film having a specific resistance value larger than that of the first metal oxide film on the surface of the second metal oxide film. 3. The resistor according to claim 1, wherein the second metal oxide film is provided so as to have a main resistance characteristic. 4. The first and third metal oxide films are provided so as to prevent characteristic deterioration of the second metal oxide film.
Or the resistor according to 2. 5. The second metal oxide film is mainly composed of tin oxide and contains at least one of antimony, iron, vanadium, chromium, nickel, molybdenum, manganese, copper, zinc, bismuth, cobalt and indium. The resistor according to claim 1 or 2, comprising: 6. The resistor according to claim 1, wherein the first and third metal oxide films mainly contain tin oxide. 7. A first insulating metal film is formed on the surface of the insulating substrate by passing the heated insulating substrate through a smoke-like first resistance film gas. The insulating base is heated to pass through a second resistance film gas to form a second metal oxide film, and the insulating base having the second metal oxide film formed thereon is heated to generate a third resistance film. A method of manufacturing a resistor, which comprises passing a gas to form a third metal oxide film. 8. The resistor according to claim 7, wherein a specific resistance value of the second metal oxide film is smaller than that of the first metal oxide film, and the first metal oxide film and the third metal oxide film are equal to each other. Production method. 9. The resistor according to claim 7, wherein the specific resistance value of the second metal oxide film is smaller than that of the first metal oxide film and that of the third metal oxide film is larger than that of the first metal oxide film. Manufacturing method. 10. The method of manufacturing a resistor according to claim 7, wherein the resistance coating gas forming the first metal oxide coating and the third metal oxide coating have the same concentration, composition or temperature. 11. The resistor according to claim 7, wherein the resistance coating gas forming the first and third metal oxide coatings is provided such that the main component of the first and third acid gold is tin oxide. Production method.