JPH05135909A - Contact type thin-film thermistor - Google Patents

Abstract

PURPOSE:To improve heat resistance, and to obtain high-speed response by composing a contact type thin-film thermistor of a thin-film thermistor element, a pair of flat metallic leads and an insulating supporter, to which a baked glass film is formed. CONSTITUTION:Electrode films 7a, 7b and conductive members 8a, 8b in a pair of through-holes 6a, 6b are formed to one surface of a plate-shaped alumina substrate 5 with the through-holes 6a, 6b. A thermo-sensitive resistor 9 is shaped onto the electrode films 7a, 7b and the substrate 5. A pair of flat metallic leads 10a, 10b and the conductive members 8a, 8b are connected by adhesive conductive sintered bodies 11a, 11b. On the other hand, a baked glass film 13 is formed onto one surface of an insulating supporter 12. The side, On which the flat metallic leads 10a, 10b are shaped, in the alumina substrate 5 is laminated onto the baked glass film 13. A glass sintered body 14 is shaped so as to include the metallic leads 10a, 10b. Accordingly, a thermistor having high heat resistance and high-speed response can be acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface temperature sensor capable of detecting the surface temperature of an object by mechanically contacting the surface of the object, and particularly to a contact type thin film which can be used up to a high temperature of 400 to 500 ° C. It is about the thermistor.

[0002]

2. Description of the Related Art Conventionally, a surface temperature sensor of this type is shown in FIG.
As shown in FIG. 4, the lead wires 2 and 2 ′ are connected to the temperature detecting element composed of the glass-encapsulated thermistor 1 element, and the glass-encapsulated thermistor 1 is bonded to the metal plate 3 with the resin 4. The metal plate 3 is mechanically brought into contact with the surface of the object by screwing or the like to detect the surface temperature (for example, Japanese Patent Publication No. 60-125535).

[0003]

However, in the above configuration, the glass-sealed thermistor element 1 is bonded to the metal plate 3 with the resin 4, and the heat resistant temperature of the resin 4 is usually about 200 ° C. or less. Therefore, the maximum operating temperature is about 20
There was a problem that the temperature was limited to 0 ° C or lower.

Further, since the glass-sealed thermistor element 1 has a cylindrical shape, the heat transfer between the metal plate 3 and the glass-sealed thermistor element 1 is poor, and the thermal response is slow (90%). There is also a problem that the thermal response time is 20 sec or more).

The present invention solves the above-mentioned problems of the prior art, and an object of the present invention is to provide a higher heat resistance than that of the prior art and a good high-speed response.

[0006]

In order to solve the above problems, a contact type thin film thermistor of the present invention comprises a thin film thermistor element, a pair of plate-shaped metal lead wires and an insulating support, and the thin film thermistor element is provided. Is a plate-shaped alumina substrate, a pair of through-holes provided in the plate-shaped alumina substrate, and electrical conduction from one surface of the plate-shaped alumina substrate to the other surface, through the through-hole. A pair of conductive members arranged, a pair of electrode films arranged to include the through hole on the one surface of the flat alumina substrate, and a temperature-sensitive layer laminated on the pair of electrode films. And a pair of plate-shaped metal lead wires arranged on the other surface of the flat plate-shaped alumina substrate of the thin-film thermistor element so as to face the pair of through-holes. Member and the pair of plate-shaped metal lead wires are respectively connected by an adhesive conductive sintered body, a glass film is formed on one surface of the plate-shaped insulating support, and the pair of plate-shaped metal lead wires The thin film thermistor element connected to is disposed on one surface of the insulating support, and the thin film thermistor element including the pair of plate-shaped metal lead wires is covered with a glass sintered body. It is a thing.

[0007]

According to the present invention, since the organic material such as resin is not used at all, the maximum operating temperature becomes high. That is, a flat alumina substrate, a glass sintered body,
Since the electrode film, the adhesive conductive sintered body and the like are formed through a high temperature firing step, it is possible to easily obtain higher heat resistance than ever before. The same heat resistance can be easily obtained by using an alumina plate for the insulating support and a conductive sintered body for the conductive member. Therefore, the heat resistance of the thin film thermistor of the present invention is ultimately dependent on the heat resistance of the temperature sensitive resistor film. This heat resistance is determined by the material of the temperature sensitive resistor film and the forming conditions. For example, a maximum temperature of 500 ° C. can be obtained by using a SiC sputtered temperature sensitive resistor film.

Since the thin film thermistor element has a flat plate shape, the heat transfer between the insulating support and the thin film thermistor element is higher than that between the conventional cylindrical glass sealed thermistor element and the metal plate. It is excellent, and the thermal response is also fast.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of the contact type thin film thermistor of the present invention. A pair of through holes 6a and 6b are provided at opposite positions of the flat alumina substrate 5. The flat alumina substrate 5 has a width of 2 mm and a length of 6 mm,
The thickness was 0.5 mm, and the diameter of the pair of through holes 6a and 6b was 0.5 mm. A conductive paste for electrodes including a pair of through holes 6a and 6b is printed on one surface of the flat alumina substrate 5 and then dried and baked to form a pair of Au-Pt thick film electrode films 7a and 7b. After that, the conductive paste for through-holes is printed on the inner surfaces of the through-holes 6a and 6b or on the space, and then dried and fired to form the conductive members 8a and 8b. The pair of thick film electrode films 7a and 7b and the pair of conductive members 8a and 8b are arranged so as to be electrically connected from one surface of the flat alumina substrate 5 to the other surface thereof. , 8b are electrically connected at their ends. Examples of the conductive paste for electrodes and the conductive paste for through holes include Ag paste, Ag-Pd paste, and A paste.
u-Pt paste or the like is used. Then, a silicon carbide (SiC) temperature sensitive resistor film 9 is formed on one surface of the flat alumina substrate 5 by a sputtering method to form a thin film thermistor element.

After the thin film thermistor element is formed in this manner, the flat plate-shaped alumina substrate 5 is contacted with the conductive members 8a and 8b formed on the pair of through holes 6a and 6b on the other surface of the flat plate-shaped alumina substrate 5 to make a pair for connection. The conductive paste is applied, and then the pair of plate-shaped metal lead wires 10a and 10b are adhered to the conductive paste for connection, followed by drying and firing to form the adhesive conductive sintered bodies 11a and 11b. At this point, an intermediate assembly is formed in which the pair of plate-shaped metal leads 10a and 10b are mechanically weakly coupled to the thin film thermistor element. In addition,
As the conductive paste for connection, the same kind of conductive paste as the conductive thin film for electrode thin film is used.

On the other hand, an alumina insulating support 12 is prepared, and a calcined glass film 13 is formed on one surface thereof. Thereafter, the above-mentioned intermediate assembly is laminated on the calcined glass film 13 formed on the plate-shaped alumina insulating support 12, and a glass is formed around the thin film thermistor element including a pair of plate-shaped metal lead wires 10a and 10b. After coating with a paste, it is dried and fired to form a glass sintered body 14. The thickness of the glass sintered body 14 is 1
~ 2 mm.

This thickness is approximately 100 times the thickness of a normal baked thick film formed through the printing process and the baking process. When the glass sintered body 14 having such a thickness is formed on the surface of the alumina insulating support 12 by a firing step, the molten glass is hard to wet on the surface of the alumina insulating support 12, and thus tends to be spherical. .. This tendency is particularly remarkable when a metal that easily wets the glass is placed in the molten glass. As a result, the adhesion area between the alumina insulating support 12 and the glass sintered body 14 is easily reduced. In consideration of this point, in the contact type thin film thermistor of the present invention, the calcined glass film 13 is previously formed on the surface of the alumina insulating support 12. Since the melted glass easily wets on the baked glass film 13, a predetermined adhesion area can be obtained. Firing glass film 13 and sintered glass body 14
The same material has the best wettability. Further, the baked glass film 13 is preferably formed except for the peripheral end portion 15 of the alumina insulating support 12. When the sintered glass film 13 is formed on the entire surface of one surface of the alumina insulating support 12, the glass sintered body 14
The glass sintered body 14 easily overflows from the alumina insulating support 12 when the amount of the glass is increased. However, when the calcined glass film 13 is formed except for the peripheral end portion 15 of the alumina insulating support 12, as described above, the melted glass is the calcined glass film 1
The reason is that the glass sintered body 14 does not overflow from the alumina insulating support 12 because it wets well on the alumina insulating support 12 but is hard to wet on the alumina insulating support 12.

A pair of plate-shaped metal lead wires 10a, 1
0b is Fe-C with a width of 1.2 mm and a thickness of 0.3 mm.
An r-based alloy plate is used. This alloy is excellent not only in heat resistance but also in that cracks do not occur when it is coated with the glass sintered body 14 having a thermal expansion coefficient similar to that of the alumina substrate 5.

In the contact type thin film thermistor structure of the present invention thus constructed, no organic substance such as resin is used compared with the conventional example, so that the maximum operating temperature is 20.
It can be above 0 ° C. That is, the flat alumina substrate 5,
Since the electrode films 7a and 7b, the conductive members 8a and 8b, the adhesive conductive sintered bodies 11a and 11b, the glass sintered body 14 and the like are all inorganic substances and are formed through a firing step at 700 ° C. or higher. A heat resistance of 500 ° C. or higher can be easily obtained. Further, since an alumina plate is used as the insulating support 12, there is no problem with this heat resistance. Therefore, the heat resistance of the thin film thermistor of the present invention is ultimately dependent on the heat resistance of the temperature sensitive resistor film 9. This heat resistance is determined by the material of the temperature sensitive resistor film 9 and the forming conditions. As the temperature-sensitive resistor film 9, there are various kinds such as a composite metal oxide, a vapor deposition film of Ge, Si, SiC, etc., a sputtered film, a thick film printed and baked, etc. Among them, the SiC sputtered temperature-sensitive resistor film has a heat resistance of 500 ° C. It has excellent resistance and temperature characteristics suitable for detecting a wide temperature range of 0 to 500 ° C. In addition, the contact type thin film thermistor of the present invention is adhered to the surface of the target object,
As a result of measuring the thermal response time, a high-speed thermal response of 7-8 sec was obtained.

[0015]

As described above, according to the present invention, the following effects can be obtained.

(1) Since it does not contain the resin used in the conventional surface temperature sensor at all and is made of an inorganic material such as ceramics and sintered bodies, it has excellent high heat resistance.

(2) Since the calcined glass film is formed on the surface of the alumina insulating support, the adhesion between the glass sintered body and the alumina insulating sintered body can be stabilized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a contact type thin film thermistor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional surface temperature sensor.

[Explanation of symbols]

 6a, 6b Through hole 7a, 7b Thick film electrode film 8a, 8b Conductive member 10a, 10b A pair of plate-shaped metal lead wires 11a, 11b Adhesive conductive sintered body 12 Insulating support 13 Firing glass film 14 Vitreous firing Union

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenzo Ochi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A thin film thermistor element, a pair of plate-shaped metal lead wires, and a plate-shaped insulating support, wherein the thin-film thermistor element is a plate-shaped alumina substrate and a pair of penetrating holes provided on the plate-shaped alumina substrate. Mouth, a pair of conductive members electrically conducted from one surface of the flat plate-shaped alumina substrate to the other surface, and arranged through the through-hole, and the one of the flat plate-shaped amyluna substrate. The pair of electrode films arranged on the surface including the through-hole, and the temperature-sensitive resistor film laminated on the pair of electrode films, and the pair of plate-shaped metal lead wires are the thin film. The thermistor element is arranged so as to face the pair of through holes on the other surface of the plate-shaped alumina substrate, and the pair of conductive members and the pair of plate-shaped metal lead wires are respectively adhesive conductive sintered. Contact with the body A glass film is formed on one surface of the flat insulating support, and the thin film thermistor element to which the pair of flat metal lead wires are connected is arranged on the one surface of the insulating support. A contact-type thin film thermistor including the pair of plate-shaped metal lead wires and the thin film thermistor element having a periphery covered with a glass sintered body. 2. The contact type thin film thermistor according to claim 1, wherein the outer peripheral portion of one surface of the flat insulating support is a non-glass film. 3. The contact type thin film thermistor according to claim 1, wherein the glass film and the glass sintered body formed on one surface of the flat insulating support are made of the same material.