JPH0228443Y2 - - Google Patents

Description

[Detailed description of the invention] The invention consists of a reference integrating circuit, a temperature sensing integrating circuit, and a humidity sensing integrating circuit on the same insulating substrate.
The present invention relates to a temperature/humidity detection device configured using a temperature/humidity sensing element that detects changes in temperature and humidity caused by pulse signal driving in correspondence with changes in the integral characteristics of an integrating circuit. Conventionally, temperature and humidity measurement (or detection) has been an indispensable technology in industry, and is used in all fields including air conditioning control. Furthermore, temperature and humidity measurements are often performed at the same location at the same time. However, devices that can detect temperature and humidity at the same time have manufacturing problems, such as thermistors, which are a typical temperature measurement device, being made by sintering transition metal oxides such as Mn, Co, and Ni, and humidity measurement devices having to be made by sintering transition metal oxides such as Mn, Co, and Ni. Ceramic, which is a typical example, is made by sintering materials such as Fe ₂ O ₃ and K ₂ CO ₃ in the same way, so it is difficult to construct them on the same insulating substrate due to differences in manufacturing conditions such as sintering temperature. was difficult.

For the reasons mentioned above, it has not been devised at present. For this reason, various types of thermistors, thermocouples, etc. are used to measure temperature, and ceramic, polymer, or electrolyte sensors are used to measure humidity, and these various temperature and humidity sensors are combined. Measuring humidity.

Therefore, two measuring devices are required to measure temperature and humidity, and there is a limit to cost reduction and miniaturization of the device.

In order to overcome the drawbacks of the above temperature measuring element and humidity measuring element, the present invention uses an amorphous semiconductor as the temperature sensitive material and a porous A ₂ O ₃ film as the moisture sensitive material, and includes a reference integrating circuit, The present invention provides a small and inexpensive temperature/humidity detection device using a temperature/humidity sensing element in which a temperature sensing integration circuit and a humidity sensing integration circuit are formed on the same insulating substrate. That is, in the present invention, a first reference integrating circuit (hereinafter referred to as a reference integrating circuit) is provided on the same insulating substrate as a first reference integrating circuit that exhibits a substantially constant value with respect to changes in temperature and humidity. A capacitor and a first reference resistor are provided, and as a second integrating circuit for temperature measurement (hereinafter referred to as a temperature-sensing integrating circuit), a second reference that shows a substantially constant value against changes in temperature and humidity. A capacitor and a temperature-sensitive resistor that responds only to changes in temperature and exhibits a change in resistance are installed.Finally, a third integrating circuit for detecting humidity (hereinafter referred to as a humidity-sensing integrating circuit) is installed to detect temperature, A temperature-sensitive and humidity-sensitive element comprising a second reference resistor that exhibits a substantially constant value in response to changes in humidity, and a humidity-sensitive capacitor that responds only to changes in humidity and exhibits a change in capacitance. This invention relates to a temperature/humidity detection device that uses a pulse signal generator to input a pulse signal to a temperature/humidity sensing element to detect changes in integral characteristics due to changes in temperature and humidity.

Regarding one embodiment of the temperature and humidity detection device of the present invention,
This will be explained using FIG.

For temperature measurement, first select switch 1 and switch 2.
Connect it to the temperature-sensing integrating circuit for temperature measurement so that it can input and output signals.

Next, from the pulse signal generator 3, the temperature and humidity sensing element 4 is
a reference integrating circuit (consisting of the first reference resistor 9 and the first reference capacitor 24), and a temperature sensing integrating circuit for temperature measurement (consisting of the temperature sensitive thin film resistor 14 and the second reference capacitor 24).
(consisting of a reference capacitor 25), the respective output signals are input to the differential amplifier 5, and the difference voltage is detected.

Then, the detected differential voltage is input to the maximum value holding circuit 6, and the voltage is held. This maximum value holding circuit 6 is driven by the output of a reset pulse circuit 7 which outputs a reset pulse signal in synchronization with the period of the output pulse of the pulse signal generator 3. If the temperature is made to correspond to the output voltage of the maximum value holding circuit 6, it can be used as a temperature measuring device.

For humidity measurement, first, select switch 1 and switch 2.
is switched so that a signal can be input to and output from a humidity sensing integration circuit (comprised of a second reference resistor 19 and a humidity sensing capacitor 26) for humidity measurement.

Next, from the pulse signal generator 3, the temperature and humidity sensing element 4 is
A pulse signal is simultaneously input to the reference integrating circuit and the humidity sensing integrating circuit for humidity measurement, and the output signal thereof is input to the differential amplifier 5, and the difference voltage is detected.

Then, the detected differential voltage is input to the maximum value holding circuit 5, and the voltage is held. The maximum value holding circuit 5 is driven by the output of a reset pulse circuit 7 which outputs a reset pulse signal in synchronization with the period of the output pulse of the pulse signal generator 3. By making the output voltage of the maximum value holding circuit 5 correspond to the humidity, a humidity measuring device can be obtained.

Next, the operating principle of the temperature/humidity detection device according to the present invention will be explained using FIG.

In the case of temperature measurement, first, a pulse signal is input from a pulse signal generator to a temperature sensing integrating circuit and a reference integrating circuit for temperature measurement of the temperature and humidity sensing element. Now, when the temperature of the object to be measured changes, the resistance value of the temperature-sensitive resistor of the temperature-sensing integrating circuit changes, the time constant of the temperature-sensing integrating circuit changes, and the integration characteristic changes.

Therefore, the output waveforms of the reference integrating circuit and the temperature sensing integrating circuit will be compared. For example, a temperature measuring device can be obtained by detecting a voltage difference using a differential amplifier and making the detected voltage difference signal correspond to temperature.

In the case of humidity measurement, a pulse signal is input from the pulse signal generator to the humidity sensing integration circuit and reference integration circuit for humidity measurement of the temperature and humidity sensing element. Now, when the humidity changes, the dielectric constant of the humidity-sensitive dielectric in the humidity-sensing integrating circuit changes, and the capacitance value of the capacitor changes. For this reason, the time constant of the humidity sensing integration circuit changes, and its integration characteristics change. Therefore, the output waveforms of the reference integrating circuit and the humidity sensing integrating circuit will be compared. For example, a humidity measuring device can be obtained by detecting a voltage difference using a differential amplifier and making the detected voltage difference signal correspond to humidity.

An embodiment of the temperature and humidity sensing element 4 used in the temperature and humidity detection device according to the present invention will be described with reference to FIGS. 2 and 3. This temperature and humidity sensing element 4 is constructed by providing three integrating circuits on the same insulating substrate 8.

The first integrating circuit is a reference integrating circuit, and includes a metal thin film resistor 9 whose resistance value changes little with changes in temperature and humidity;
An ohmic electrode 10 is connected to the metal thin film resistor 9 for pulse signal input, and an ohmic electrode is one electrode forming a capacitor and is connected to the other side of the metal thin film resistor 9 for signal output. 11, an insulator 12 exhibiting a substantially constant dielectric constant with respect to changes in temperature and humidity, and the other ohmic electrode 13 constituting the capacitor.

The second integrating circuit is a temperature-sensitive integrating circuit for temperature measurement, and includes a temperature-sensitive thin film resistor 14 that responds to changes in temperature and exhibits an almost constant value to changes in humidity, and a pulse signal input circuit. An ohmic electrode 15 connected to the temperature sensitive thin film resistor 14, an ohmic electrode 16 which is one electrode forming the capacitor and is connected to the other end of the temperature sensitive thin film resistor 14 and is for signal output, , an insulator 17 exhibiting a substantially constant dielectric constant with respect to changes in humidity, the ohmic electrode 16, and an ohmic electrode 18 provided to sandwich the insulator 17 to form a capacitor.

The third integrating circuit is a humidity sensing integrating circuit for measuring humidity, and includes a metal thin film resistor 19 that exhibits a nearly constant resistance value against changes in temperature and humidity, and a metal thin film resistor 19 for pulse signal input. an ohmic electrode 20 connected to the body 19;
An ohmic electrode 21 is connected to the other electrode of the metal thin film resistor 19 and serves as a signal output, which is one electrode constituting a humidity sensing capacitor, and an ohmic electrode 21 which is connected to the other electrode of the humidity sensing capacitor and is used for signal output. It is composed of a humidity-sensitive dielectric material 22 having a dielectric constant of , the ohmic electrode 21, and another ohmic electrode 23 provided to sandwich the humidity-sensitive dielectric material 22 to constitute a humidity-sensitive capacitor.

The metal thin film resistors 9 and 19 are made of tantalum nitride, and the insulators 12 and 17 are made of SiO ₂
The moisture-sensitive dielectric 22 is made of A ₂ O ₃ and the temperature-sensitive thin film resistor 14 is made of amorphous Si.

FIG. 4 shows the temperature characteristics of amorphous Si used for the temperature-sensitive thin-film resistor of the temperature-humidity detection device according to the present invention. The contents are the same as those disclosed in the application documents filed by the person on the same day (Utility Application No. 57-148934).

FIG. 5 shows the characteristics of A ₂ O ₃ used in the humidity-sensitive capacitor used in the present invention, that is, the capacitance-relative humidity characteristics. In the figure, the black circles are the average values,
The range of vertical lines indicates the maximum and minimum values. The measured humidity is
Three points were set at 20°C: 11%, 43%, and 59%, and saturated salts were LiC, K ₂ CO ₃ , and NaBr, respectively.
The low dew point gas for zero adjustment is commercially available dew point -60.
°C _N2 gas was used. The measurement container used was a stainless steel container with a capacity of 270 ml and equipped with a thermometer. The measurement of humidity characteristics was carried out after a 50 ml beaker containing saturated salt was placed in the stainless steel container and the temperature and humidity reached equilibrium. The capacitance was measured using an LCR meter with a measurement frequency of 1MHz.

The present invention will be explained using specific numerical values as follows.

(1) Temperature-sensing characteristics When amorphous Si is used as a temperature-sensitive thin film resistor, the conductivity is 20°C as shown in Figure 4 in the case of p-type.
(293°K) becomes 0.92 (Ω・cm) ^-1 , which is 40°C.
(313°K), it becomes 0.94 (Ω・cm) ^-1 . Therefore,
A temperature-sensitive thin film resistor is formed so that the resistance value is 150KΩ at 20°C. This temperature sensitive thin film resistor is 40
It shows a resistance value of 153KΩ at ℃. Also, the reference capacitor is formed to have a capacitance of 200 pF.

When an integrating circuit is constructed with a temperature-sensitive thin film resistor exhibiting the characteristics described above and a reference capacitor, the temperature is 20°C.
The time constant is 30.0×10 ^-6 sec when the temperature is 40
The time constant at ℃ is 30.6×10 ^-6 sec.

On the other hand, if we configure the reference integration circuit so that the capacitance of the reference capacitor is 200pF and the resistance value of the reference resistor is 100KΩ, the time constant is 20.0×10 ^-6 sec.
becomes. If you input a pulse signal with an amplitude of 5V and a pulse width of 40.0×10 ^-6 sec to these two integrating circuits, input the output signal to the differential amplifier, and then input the output signal of the differential amplifier to the maximum value holding circuit. ,20℃
The voltage output from the maximum value holding circuit is
It becomes 0.74V. Also, at 40℃, it becomes 0.78V.

(2) Moisture-sensitive characteristics When a humidity-sensitive capacitor is constructed using A ₂ O ₃ , for example, as shown in Figure 5, the capacitance is 210 pF at a temperature of 20°C and a relative humidity of 20%;
At ℃ and 40% relative humidity, the capacitance is 275pF. The resistance value of the reference resistor is formed to be 100KΩ. When an integrating circuit is constructed using these humidity-sensitive capacitors and a reference resistor, the time constant at a temperature of 20°C and a relative humidity of 20% is 21.0×10 ^-6 sec,
The time constant when the temperature is 20℃ and the relative humidity is 40% is 27.5×
10 ^-6 sec. On the other hand, as in the case of temperature measurement, the reference integrating circuit has a capacitance of 200 pF and a resistance value of
When configured for 100KΩ, the time constant is 20.0
×10 ^-6 sec.

These two integrator circuits have an amplitude of 5V and a pulse width of
When a 40.0×10 ^-6 sec pulse signal is input, the output signal is input to the differential amplifier, and the output signal of the differential amplifier is input to the maximum value holding circuit, the temperature is 20℃,
When the relative humidity is 20%, the voltage output from the maximum value holding circuit is 0.09V. Also, the temperature is 20℃, relative humidity
At 40%, it is 0.58V. In this way, changes in temperature and humidity can be detected by voltage differences.

The principle of the temperature/humidity detection device according to the present invention and one embodiment thereof have been explained above with reference to the drawings.

The temperature and humidity detection device of the present invention consists of an element comprising an integrating circuit for temperature and humidity, that is, an element comprising three integrating circuits for reference, temperature sensing, and humidity sensing (Utility Application No. 1983-1 filed by the same applicant). 148934), the same measurement circuit can be used and a compact temperature/humidity detection device can be obtained. In addition, by installing a changeover switch, it is possible to select either the output voltage of the temperature-sensitive integrating circuit or the output voltage of the humidity-sensitive integrating circuit, so that the desired physical quantity of either temperature or humidity can be controlled. Can be measured. Therefore, for example, it can be used as a temperature-hygrometer-equipped wristwatch that incorporates a temperature-hygrometer, or it can be used as a temperature and humidity monitor by incorporating it into various measuring instruments. In terms of performance, the temperature and humidity sensing element used in the present invention is driven by a pulse signal, so there are fewer measurement errors due to heat generated by the element itself, and reliability is improved. In addition, since temperature and humidity are measured using the same element and device, the measuring device can be inexpensive.

As described above, the temperature/humidity detection device of the present invention has many advantages not seen before, and is of great industrial utility.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the temperature/humidity detection device according to the present invention. FIG. 2 is a front view showing an embodiment of the temperature and humidity sensing element used in the temperature and humidity detecting device of the present invention, and FIG. 3 is a sectional view taken along the broken line X-X' in FIG. Further, FIG. 4 shows an example of the conductivity-temperature characteristics of amorphous Si used in the present invention, and FIG. 5 shows an example of the capacitance-relative humidity characteristics of A ₂ O ₃ used in the present invention. In the figure, 1 and 2 are changeover switches, 3 is a pulse signal generator, 4 is a temperature and humidity sensing element, 5 is a differential amplifier, 6 is a maximum value holding circuit, 7 is a reset pulse circuit, 8 is an insulating substrate, 9 is a metal thin film resistor, 1
0 and 11 are ohmic electrodes, 12 is an insulator, 13
is an ohmic electrode, 14 is a temperature-sensitive thin film resistor, 15 is
and 16 are ohmic electrodes, 17 is an insulator, 18 is an ohmic electrode, 19 is a metal thin film resistor, 20 and 21 are ohmic electrodes, 22 is a moisture-sensitive dielectric, 23
24 is a capacitor composed of an ohmic electrode 11, an insulator 12, and an ohmic electrode 13; 25 is a capacitor composed of an ohmic electrode 16, an insulator 17, and an ohmic electrode 18; 26 is an ohmic electrode 21; Moisture sensitive dielectric 2
2 and an ohmic electrode 23, respectively.

Claims (1)

[Claims for Utility Model Registration] (1) A reference integrating circuit consisting of a first reference resistor 9 and a first reference capacitor 24, and a temperature-sensitive resistor 1
4 and a second reference capacitor 25; a humidity-sensing integrating circuit including a second reference resistor 19 and a humidity-sensitive capacitor 26; the reference integrating circuit; and the temperature-sensing integrating circuit. and a pulse signal generator 3 for supplying a pulse voltage to the humidity-sensing integrating circuit, and selector switches 1 and 2 for selecting either the output voltage of the temperature-sensing integrating circuit or the output voltage of the humidity-sensing integrating circuit. , means for detecting temperature and humidity or one of temperature and humidity by comparing the output voltage selected by the changeover switch and the output voltage of the reference integrating circuit. (2) The means for detecting the temperature and humidity detects the difference voltage between the output voltage of the reference integrating circuit and the output voltage of the temperature-sensing integrating circuit, and the output voltage of the reference integrating circuit and the output of the humidity-sensing integrating circuit. Claim 1 of the utility model registration claim is characterized in that the system comprises a differential amplifier 5 that outputs a differential voltage, and a maximum value holding circuit 6 that holds the maximum value of the output of the differential amplifier. Temperature and humidity detection device.