JPS5884404A - thin film thermistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to a thermistor that detects temperature by mechanically contacting an object whose temperature is to be detected, such as a pot, when cooking food, and through the bottom of the pot.Page 2 This relates to a thermistor that detects temperature.

Conventionally, this type of temperature detection has been carried out by mechanically bringing a fast-responsive thin film thermistor into contact with the pot bottom 1, as shown in FIG. This fast-responsive thin-film thermistor consists of a thin-film thermistor chip formed by forming an electrode film 3 and a temperature-sensitive resistor film 4 on one surface of a flat ceramic insulating substrate 2, and a support container 6 made of titanium (Ti) foil 6 or The thin film thermistor chip is connected with a brazing material layer 7 via a zirconium (Zr) foil 6, and further coated with an insulating coating material 8. Furthermore, the lead wire 11 is connected to the electrode film 3. In this fast-response thin-film thermistor, the thin-film thermistor chip with a small heat capacity and the support container 6 are connected by brazing, so that the thermal resistance from the pot bottom 1 to the temperature-sensitive resistor film 4 is small. This result 1. Provides high-speed response. Normally, the response required when cooking hotpot dishes is the 90-chi response time (starting from the time when the bottom 1 of the pot at temperature T'2°C suddenly mechanically contacts the thermistor maintained at room temperature T1°C), and the thermistor temperature is required to be approximately 8 seconds or less in terms of the time required to reach T,+o,e (T2-d,)°C. The 90% response time of this fast-responsive thin film thermistor was 3 to 6 seconds without the insulating coating 8. However, when the insulating coating material 8 is formed, the 90-meter response time is relatively slow and its variation is large, resulting in a disadvantage of 4 to 10 seconds. The relative slowness of the 90-chi response time is due to the heat capacity of the insulation/coating material 8, so
Technically unavoidable. On the other hand, the magnitude of the 9o% response time corresponds to the magnitude of the applied amount of the insulating coating material 8, that is, the magnitude of the heat capacity, so by controlling the applied amount of the insulating coating material 8 to a constant amount, the variation can be reduced. It is possible to do so. However, in the conventional fast-response thin film thermistor, it is difficult to control the amount of applied insulating coating material 8 to a constant amount due to its structure. That is, this type of insulating coating 8
is usually formed through a process in which a fluid with a constant viscosity, such as a slurry of glass powder and an organic binder, is applied and then cured. Moreover, it was difficult to control the amount of coating to a constant level.

If the 90-chip response time is 8 seconds or more, it cannot be used for temperature control in pot cooking, so those with a large coating amount of the insulating coating 8 also have disadvantages such as a decrease in yield and an increase in price.

The present invention eliminates these conventional drawbacks and aims to reduce the variation in temperature responsive silicon.

In order to achieve this object, the present invention provides a thin film thermistor chip having an electrode film and a temperature sensitive resistor film formed on one surface of a flat ceramic insulating substrate, and a support container made of T1 foil or Zr foil. A shielding plate is provided in the supporting container so as to surround the periphery of the thin film thermistor chip, and the thin film thermistor is coated with an insulating coating material in the surrounded area. This is what I did. With this structure, when forming an insulating coating, even if a fluid with a constant viscosity is applied, it will be blocked by the shielding plate and the fluid will not flow beyond the shielding plate. The coating amount can be controlled to a constant amount.

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 2, the same numbers as mentioned above indicate the same members, and 9 is a shielding plate, and this shielding plate 9 is provided in the support container 6 so as to surround the periphery of the thin film thermistor chip. The thermistor chip is coated with an insulating coating 8.

To explain the temperature response of this configuration, the magnitude of the response time is approximately determined depending on the amount of the insulating coating 8 applied. 90% response time was about 4 to 7 seconds. At this time, the thin film thermistor chip has an alumina substrate 2 (1,8111W x 6.5f
An Au-Pt thick film electrode film 3 and a Si temperature sensitive resistor film 4 are formed on one surface of the iLX0.5 layer (t), and the material of the support container 6 and shielding plate 9 is 5US- 4
30 plates (thickness o, 4 m'), the shielding plate 9 is the support container 5
Spora 6... is fixed by welding. The thin film thermistor chip and the support container 6 are connected by brazing with a silver brazing material layer 7 via a Ti foil 7. The insulating coating 8 is made of low melting point glass such as ZnO-B with a softening point of 636°C.
glass or alumina coating, e.g.
A liquid heat-curable alumina-based paste is used. The thermistor constructed in this way had a 90-90 response time of 4 to 7 seconds as described above, and had excellent stability. That is, sso in air
℃ for 100 hours or in air at 360℃ for 1 hour.
After applying 3000 cycles of heat cycles of 6 minutes←room temperature and 15 minutes, and after being left in the air at 70°C and a relative humidity of eo% or more for 1000 hours, the rate of change in resistance value was ±3 inches or less.

The shielding plate 9 and the support container 6 are made of the same material and are made of Ti,
Preferably, it is a type selected from the group Zr, 5US-430. The reason for this is that when the shielding plate 9 is fixed to the support container 6 so as to surround the periphery of the thin film thermistor chip, it is easiest to fix it by welding. This is because both are made of the same material, which is superior in terms of weldability. In addition, the flat ceramic substrate 2 of the thin film thermistor chip includes:
Alumina substrates are often used. It is desirable that the thermal expansion coefficient of the support container 6 is similar to that of the flat ceramic substrate 2, that is, the alumina substrate, and in this respect, the material of the support container 6 is Ti, Zr, 5US-4.
One type selected from 30 counties is desirable.

As is clear from the above description, the thin film thermistor of the present invention provides the following effects.

(1) A shielding plate is provided in the support container to surround the periphery of the thin film thermistor chip, and the thin film thermistor chip is coated with the insulating coating within this surrounded area, so the amount of the insulating coating applied is constant. It is easy to maintain the same temperature, and it is easy to reduce variations in temperature response.

(2) A small amount of insulating coating material can sufficiently protect the thin-film thermistor chip from water, dust, and external stress.

FIG. 1 is a sectional view schematically showing a conventional fast-response thin-film thermistor, and FIG. 2 is a sectional view schematically showing an embodiment of the fast-response thin-film thermistor of the present invention.

DESCRIPTION OF SYMBOLS 1... Pot bottom, 2... Flat ceramic insulating substrate, 3... Electrode film, 4... Temperature sensitive resistor film, 6... ...Support container, 6...T
i foil or Zr foil, 7r...brazing material layer, 8...
...Insulating covering material, 9... Shielding plate. 11
······Lead.

Name of agent: Patent attorney Toshio Nakao and one other person
Figure 1

Claims (1)

[Claims] (1) A thin film thermistor chip consisting of an electrode film and a temperature-sensitive resistor film formed on one surface of a flat ceramic insulating substrate and a supporting capacitor are interposed with titanium (Ti) foil or zirconium (Zr) foil. Both are connected by brazing, and a shielding plate is provided in the support container so as to surround the periphery of the thin film thermistor chip, and within the enclosed area (2) the shielding plate and the support container are made of the same material, Ti.