JPH02665Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field of invention] The present invention relates to a temperature measurement sensor.

[Technical background of the invention and its problems] Thermocouples and thermistors have been widely used as temperature measurement sensors. Among these, thermocouples have a wide measurement temperature range and high measurement accuracy, but their output voltage is small at a few mV.
A stable DC amplifier with high amplification degree is required. In addition, thermistors have a large change in resistance value with respect to temperature changes and are highly sensitive, but because the change in resistance is exponential, signal processing such as compression of the amount of change and linearization is required. do.

As is clear from the above, when a thermocouple or thermistor is used as a sensor, the configuration of the temperature measurement circuit becomes complicated, and the temperature measurement device tends to be expensive and difficult to use.

[Purpose of the invention] The present invention was created based on the above circumstances, and its purpose is to obtain a temperature measurement sensor that can measure temperature with high sensitivity without using a complicated temperature measurement circuit. .

[Summary of the invention] The temperature measurement sensor of the invention is made by molding and sintering a powder made of zinc oxide, chromium oxide, etc. as the main ingredients and adding a moisture sensitive element to it, and attaching electrodes to this sintered body. The structure is characterized in that the periphery of the constructed moisture-sensitive ceramic element is covered with a small breathable member.

[Example of the idea] The humidity sensor is a powder whose main components are zinc oxide, chromium oxide, etc., with addition of lithium or vanadium glass as a humidity sensing element, and electrodes are attached to porous ceramic that is molded and sintered at high temperature. Configure. This humidity sensor detects humidity by utilizing the fact that the electrical resistance inside the sintered body changes exponentially in response to the external relative humidity due to adsorption and desorption of water molecules on the crystal surface.

However, the electrical resistance of the moisture-sensitive ceramic having the above structure changes not only with humidity but also with temperature, and therefore has the disadvantage that accurate relative humidity cannot be obtained unless temperature compensation is performed. FIG. 1 shows the temperature dependence of the relationship between relative humidity and the electrical resistance value.

The temperature measurement sensor of the present invention takes advantage of the above drawbacks. In other words, the surface of the moisture-sensitive ceramic element is covered with a glass or resin film with low air permeability.
The temperature measurement sensor of the present invention is constructed by sealing the moisture-sensitive ceramic element in a glass tube or resin tube to block the influence of humidity on the moisture-sensitive ceramic element.

Figure 2 shows its characteristics. From this figure, the temperature
The resistance value of the sensor of the present invention changes by nearly an order of magnitude in the range of 0°C to 50°C, indicating that it can be used as a highly sensitive temperature measurement sensor. Also, 0°C ~
It can also be seen that in the 40°C living temperature range, there is a proportional relationship between ambient temperature and resistance value, and that changes in resistance value can be directly read as temperature changes.

FIG. 3 shows an example of a temperature measurement circuit using the sensor of the present invention.

The output of the temperature measurement sensor 1 is amplified by an amplification circuit 2, and the output is displayed or recorded on a display or recording device 3. Since the sensor of the present invention has the above-mentioned characteristics, it does not require a logarithmic compression circuit or a linearization circuit, which are indispensable in a circuit using a thermistor as a sensor, and the simple temperature measurement circuit described above is sufficient.

[Effects of the invention] The temperature measurement sensor of the invention is highly sensitive and has a proportional relationship between the resistance value and the ambient temperature in the living temperature range, so the temperature measurement circuit can be of a simple configuration.
A temperature measuring device that is inexpensive and easy to use can be constructed.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the temperature dependence of a moisture-sensitive ceramic element, Fig. 2 is a characteristic diagram of an embodiment of the present invention, and Fig. 3 is a diagram showing the temperature dependence of a moisture-sensitive ceramic element.
The figure is a block diagram of a temperature measurement circuit using the temperature measurement sensor of the present invention.

Claims (1)

[Scope of utility model registration request] A moisture-sensitive ceramic element is formed by molding and sintering a powder consisting mainly of zinc oxide, chromium oxide, etc. and adding a moisture-sensitive element, and then attaching electrodes to this sintered body. A temperature measurement sensor characterized by being covered with a material.