JPS5839367B2 - Temperature/humidity detection device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a temperature/humidity sensing device.

Conventionally, F has been used as a sensor for humidity measuring devices and humidity regulating devices.
Humidity-sensitive resistors are generally used, which are mainly composed of metal oxides with excellent water absorption properties such as e20g and Al2O3, and detect humidity from the resistance value that changes in response to humidity.However, for example, in air conditioning systems, In general, there are more cases in which it is required to detect humidity and temperature together than to detect humidity alone, such as when humidity control is performed at the same time as humidity control. For example, it was necessary to separately use the humidity-sensitive resistor for detecting humidity and a thermistor for detecting temperature, and to adopt a two-system circuit configuration in which the humidity detecting circuit and the temperature detecting circuit were made independent of each other.

This has resulted in a disadvantage that the circuit configuration becomes complicated and the manufacturing cost of the device also increases.

Therefore, an object of the present invention is to provide a temperature/humidity detection device that can detect both temperature and humidity with a simple and inexpensive circuit configuration.

Embodiments of the present invention will be described below based on the drawings.

First, an example of a temperature/humidity sensing element used in this temperature/humidity sensing device will be explained in detail with reference to FIG. 1.

First, as a starting material, KCO3# Ta205 is wet mixed and then dried to form a dry powder.

Next, this powder raw material is molded into a size of 4×4×0.2511 (
Molding pressure 750kp/α2), KTaO as sintered body 1
s oxide porcelain is produced.

Further, a RuO2-based electrode paste is applied to the sintered body 1 and baked at 800°C to form an electrode 2 to form a temperature/humidity sensing element.

The electrode material may include Ag in addition to RuO2.

Ni, Znt Cr, PcL Au, Ptt 5ne
Similar effects can be obtained by applying Cup AL In by an electrode paste baking method, thermal spraying method, vapor deposition method, or the like.

Electrodes made of metal oxides and semiconductors whose main components are nickel oxide, zinc oxide, and indium oxide can also be formed by such a method.

Regarding the characteristics of the temperature/humidity sensing element having the above configuration,
This will be explained below based on the experimental results.

The graph shown in FIG. 2 shows that both electrodes 2 and 2 at a temperature of 20°C
When a low frequency power supply of 10H2-IV is applied between 2,
This figure shows the change in electrical impedance of the temperature/humidity sensing element as the relative humidity changes, and it can be seen that the electrical impedance decreases as the humidity increases.

Furthermore, in an experiment on the above characteristics conducted at a temperature of 80°C under the same applied power supply conditions, it was found that there was almost no effect due to temperature differences;
It was found that the change in electrical impedance of the humidity sensing element depends only on humidity under conditions where a low frequency power source is applied.

The graph shown in Figure 3 shows the humidity at 50% RH (1 to 95°C).
This shows the change in electrical impedance of the temperature/humidity sensing element due to temperature change when a high frequency power source of 1000 KH2-IV is applied between both electrodes 2 and 2. It can be seen that the is changing.

Also, under the same applied power supply conditions, the relative humidity was 10%,
It was found that even when the ratio was set to 99%, there was almost no change in the above characteristics.

The graph shown in FIG. 4 shows frequency-electrical impedance characteristics at a temperature of 20° C. when humidity is used as a parameter, where A is a humidity of 20% RH and B is a humidity of 40% RH.

C shows the characteristics when the humidity is 60% RH, and D shows the characteristics when the humidity is 80% RH, but it can be seen that high frequencies are not affected by changes in humidity at all.

From the above experimental results, it is clear that the change in electrical impedance of this temperature/humidity sensing element depends on humidity under low frequency power supply conditions, and that the change in electrical impedance depends on temperature under high frequency power supply conditions. It can be seen that it has dependent properties.

The structure of this temperature/humidity sensing element is not limited to the above-mentioned KTaO3 component;
3 p S rTt 03 s Pb'r i 03
pCaTi 03 tPbZr03 , KNbO3,
NaNbO3, LiNbO3゜L 1Ta03, P
b (Mg 1/'l Nb 2/'l ) 03 and other berovskite typhs; tungsten bronze typhs: No. 90 chlorite type, spinel type, and by adding one or more compounds such as metal oxides. Moreover, it is possible to obtain an element with fast response, high sensitivity with extremely little characteristic deterioration, and excellent separation of temperature and humidity when detecting temperature and humidity.

Furthermore, by adding other additives, the customization can be controlled to a high degree within a certain limited humidity or temperature sensing range.

This temperature/humidity sensing element also has excellent heat resistance, so even if the element becomes contaminated with airborne particles, it can be returned to its original state by heating and cleaning. can.

Note that the dimensions, shape, and structure of this element are not limited to those in the example above, and may be of various dimensions, shapes, and structures.
Any shape is possible.

FIG. 5 shows an embodiment of a temperature/humidity detection device using the temperature/humidity detection element described above.
The temperature/humidity sensing element S and the resistor (IOKΩ) Rs are connected to the power supply, which is configured with C-2 in parallel and can be selectively connected to each of the oscillators 08C-1 and 08C-2 using a changeover switch SW. Configure by connecting in series.

With this configuration, for example, when the changeover switch SW is turned to the a side, it is connected to the oscillator 08C-1, and an output signal corresponding to the humidity change is obtained to the resistor, and the changeover switch SW is turned to the b side. When defeated, oscillator 08C
-2, and an output signal corresponding to the temperature change is obtained from the resistor R8.

In addition, when using the configuration of this embodiment, the temperature is 0°C to 10°C.
Detection is possible at 0° C. and humidity in the range of 10+ RH to 100+ RH.

As described above, this temperature/humidity detection device can detect temperature and humidity with a single circuit configuration, and can be used for temperature/humidity control in fields such as air conditioning management, meteorology, food industry, medical chemistry, etc. The configuration of the device for this purpose can be simplified, and the cost of the device can be reduced.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a temperature/humidity sensing element used in an embodiment of the present invention, FIG. 2 is a diagram showing humidity vs. impedance characteristics of the temperature/humidity sensing element, and FIG. 3 is a diagram showing temperature/humidity sensing elements.
FIG. 4 is a diagram showing the temperature vs. impedance characteristic of the humidity sensing element, FIG. 4 is a diagram showing the frequency vs. impedance characteristic of the temperature/humidity sensing element, and FIG. 5 is a circuit diagram showing an embodiment of the temperature/humidity sensing device. 1... Sintered body (oxide porcelain), 2... Electrode, osc
-1,08C-2... Oscillator, SW... Changeover switch, S... Temperature/humidity detection element, RS... Resistor.

Claims (1)

[Claims] I A temperature/humidity sensor characterized by connecting a temperature/humidity sensing element with an electrode surface provided on an oxide magnet whose main component is KTaOs and a power supply circuit that can selectively change the frequency.
Humidity detection device.