JPH04289448A - Temperature and humidity sensor and method for measuring temperature and humidity by using temperature and humidity sensor - Google Patents

Abstract

PURPOSE:To obtain the accurate temperature and humidity sensor wherein both sensors for temperature and humidity are formed as a unitary body by arranging both the humidity sensor and the temperature sensor at a same Position. CONSTITUTION:In a humidity sensor, a moisture sensitive film 1 is applied on a metal electrode 2 which is to become the first electrode, and a counter electrode 3 which is to become the second electrode has the linear shape. The counter electrode 3 is wound around the metal electrode 2 so that the electrode 3 comes into contact with the moisture sensitive film 1. The counter electrode 3 is formed by using a linear temperature measuring resistor material. At this time, the metal electrode 2 is made of stainless steel, and the moisture sensitive film 1 is made of a phosphoric acid salt. Meanwhile, the temperature measuring resistor material is formed as a noble metal wire or a noble-metal plated wire. This temperature and humidity sensor 8 is used, and the humidity is measured based on the change in resistance value or the change in capacitance value across both electrodes of the temperature and humidity sensor. The temperature can be measured based on the change in resistance value across the counter electrode 3.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a humidity sensor in a broad sense used as a humidity sensor, moisture condensation sensor, moisture measurement sensor, etc. - Concerning how to measure humidity.

0002

[Prior Art] Conventionally, humidity sensors used for this type of application have been made of ceramics, polymers, electrolytes, etc. as moisture-sensitive substances that sense humidity, as shown in Japanese Patent Laid-Open No. 59-48647. It's being used. Most of these were constructed by forming electrodes by printing on an insulating substrate, and then forming a film of a moisture-sensitive substance on top of the electrodes. By the way, this type of sensor element has a complex structure, is large in size, and its characteristics change due to age-related changes in the moisture-sensitive material or dirt from the outside world, resulting in errors in humidity measurements. Therefore, there was a problem of low reliability. The inventors have invented a humidity sensor to solve these problems, and have filed applications such as Japanese Patent Application No. 62-261857 and Japanese Patent Application No. 63-292416. In addition, the patent application No. 1-281767 provides a humidity sensor suitable for easily calibrating the humidity sensor and measuring the water activity of food.
We have also applied for the No.

0003

[Problems to be Solved by the Invention] By the way, the humidity referred to here means relative humidity, and relative humidity varies greatly depending on the temperature. For example, at 25°C and 100% relative humidity
air is 94.2% at 26°C, and a change of 1°C reduces the
There is a difference of almost %. For this reason, measuring temperature is essential to measuring relative humidity, and there is little point in measuring only relative humidity without measuring temperature. In addition, in fields related to life activities, such as making human housing more comfortable, growing vegetables in greenhouses, and manufacturing food and medicine using microorganisms, it is extremely important to control the temperature and humidity optimally for the target organisms. It is becoming. Furthermore, the humidity sensitivity characteristics of general humidity sensors change somewhat depending on temperature, so temperature correction is required. For this reason, measurements are often performed using both a humidity sensor and a temperature sensor, and since both sensors need to be placed at the same location, it is strongly recommended to integrate both temperature and humidity sensors into a compact unit. It is requested. The present invention aims to solve the above-mentioned problems (problems) of the conventional ones and to provide a temperature-humidity sensor that meets the above-mentioned demands.It is only a matter of time and effort to install both a temperature sensor and a humidity sensor. However, considering that it is disadvantageous in terms of miniaturization and economy, the present invention provides a temperature/humidity sensor that has the functions of both a temperature sensor and a humidity sensor in one sensor. The present invention also provides a method for measuring temperature and humidity using this temperature and humidity sensor.

0004

[Means for Solving the Problems] As a result of our studies to develop the above-mentioned temperature and humidity sensor, we found that the prior art described in the specifications of Japanese Patent Application No. 63-292416 filed by the present applicant, etc. The present invention was developed using the following. In other words, we focused on the fact that the prior art humidity sensor uses a thin wire such as a gold-plated stainless steel wire for the counter electrode, and devised the idea of using this thin wire itself as a temperature-measuring resistor, resulting in the present invention. The structure of a humidity sensor according to the present invention is shown in FIG. A metal electrode 2 serving as a first electrode is coated with a moisture sensitive body coating 1, and a counter electrode 3 serving as a second electrode is wound around the moisture sensitive body coating 1 so as to be in contact with the moisture sensitive body coating 1. A lead wire is connected to the metal electrode 2, and this is used as a humidity measuring terminal 6. Furthermore, one end of the opposing electrode is used as a common terminal 5, and the other end is used as a temperature measurement terminal 7. FIG. 2 shows the change in AC impedance between the common terminal 5 and the humidity measuring terminal 6 of the temperature/humidity sensor 8 constructed in this manner. As shown in FIG. 2, the logarithm value of AC impedance changes linearly with relative humidity, which satisfies the humidity sensitivity characteristics of a general humidity sensor. Further, FIG. 3 shows the temperature change in the DC resistance value between the common terminal 5 and the temperature measurement terminal 7. As shown in the figure, the resistance value is approximately 50Ω, and the resistance value changes linearly with temperature. It is well known that the resistance value and temperature gradient vary depending on the material of the counter electrode, and that these depend on the specific resistance and its temperature coefficient. As for the electric circuit for measuring the humidity, it is possible to use an AC impedance type measuring circuit used in general ceramic type or polymer type humidity sensors. Furthermore, for temperature, a commonly used temperature measurement circuit using a resistance temperature detector can be applied. And the humidity of both signals is several kilohms in AC measurement.
~1MΩ, while the temperature is 50Ω when measured by direct current.
They are placed before and after each other, so there is almost no interference with each other's measurements. A schematic diagram of the circuit configuration is shown in FIG. The temperature is determined by the DC resistance between the common terminal 5 and the temperature measurement terminal 7.
The humidity is measured by the humidity measuring circuit 11 and the AC resistance between the common terminal 5 and the humidity measuring terminal 6 is measured and displayed on the temperature display 13.
The temperature change in the humidity sensitivity characteristic is corrected using the temperature correction signal 12 obtained from the temperature measurement circuit 10, and the result is displayed on the humidity display 14. With the temperature and humidity sensor configured in this way, temperature and humidity can be easily measured with a single element. It is also possible to measure the temperature and humidity at the same location.

[0005]

[Operation] The temperature and humidity sensor according to the present invention allows temperature and humidity to be measured simultaneously with the same element, which is convenient and economically advantageous. In addition, since there is no need to install the temperature sensor and humidity sensor separately, not only is the installation effort and space required halved, but the temperature and humidity can be measured in the same place, so the humidity sensor's humidity sensitivity characteristic Correction becomes more accurate,
It is now possible to measure humidity with high precision. This point provides a useful advantage in the needle-shaped humidity sensor, which is the prior art disclosed in Japanese Patent Application No. 1-281767 filed by the present applicant. Further, since the temperature/humidity sensor according to the present invention has a simple structure, it is difficult to break down and can be manufactured easily and inexpensively. In addition, since temperature and humidity can be measured using three lead wires, wiring can be reduced.

[0006]

[Embodiment] The structure of the present invention will be specifically explained below using an example in which a temperature/humidity sensor of the present invention was manufactured. Wire diameter 0.9
mmφ SUS304 stainless steel material (JIS-G-43
09) was used as a material, and was degreased by immersing it in a 2% aqueous solution of fine cleaner 4360 (manufactured by Nippon Parkerizing Co., Ltd., hereinafter referred to as "our company"), an alkaline degreasing material, at a temperature of 60°C for 3 minutes. , After washing with water, nitric acid 75g/L, hydrofluoric acid 25g
After pickling with /L mixed solution and washing with water, 6.2g of zinc ions
/L, phosphate ion 18g/L, nitrate ion 10g/L
The electrolysis time was 60 minutes using a zinc phosphate film treatment solution consisting of
Electrolytic treatment was performed at an electrolytic current of 4 A/dm2 with the stainless steel material side serving as a cathode. Note that a carbon electrode was used as the anode. The components of the obtained film were determined by X-ray diffraction and chemical analysis to include 3% metallic zinc and 9% zinc phosphate tetrahydrate.
It was confirmed that it contained 7%. Also, the film weight is 10g/
It was m2. The film thus obtained was heated to 600°C.
In the infrared heating furnace set to -40℃ dew point in the heating furnace
Baking was performed for 20 minutes while flowing dry air at a flow rate of 2 L/min. This coated stainless steel wire was used as a metal electrode, and a 60 μmφ gold-plated stainless steel wire was wound as a counter electrode with 40 turns at a pitch of 0.75 mm using a winding machine. This electrode configuration is shown in FIG. As shown in FIG. 1, a lead wire is attached to the metal electrode, and this is used as the humidity measuring terminal 6. In addition, one end of the opposing electrode is connected to a common terminal 5,
The other end is used as a temperature measurement terminal 7. This temperature/humidity sensor element is placed in a tank of a branch type humidity generator (JIS-Z8806) to change the relative humidity, and the AC impedance value between the common terminal 5 and humidity measurement terminal 6 of this temperature/humidity sensor is determined by Ando. Measurement was performed using an LCR meter model AG-4311 manufactured by Denki Co., Ltd. FIG. 2 shows the relationship between relative humidity and AC impedance value at an applied voltage of 1 V, 1 KHz, and 20°C. Although the AC impedance is scaled with logarithmic values, a temperature/humidity sensor element was obtained in which the AC impedance changes linearly from a low humidity region to a high humidity region. Further, the temperature inside the tank was changed and the change in DC resistance between the common terminal 5 and the temperature measuring terminal 7 of the temperature/humidity sensor was measured using a digital multimeter. The results are shown in FIG. As shown in FIG. 3, the DC resistance changes linearly with temperature. As described above, according to the present invention, a temperature/humidity sensor that can satisfactorily measure both temperature and humidity with a single element was obtained.

[0007]

[Effects of the Invention] Since the present invention is constructed so that both temperature and humidity can be measured with an integrated temperature and humidity sensor as described above, it has the following excellent effects. ■It is convenient because it can measure temperature and humidity simultaneously with a single element. ■It has a simple structure, is hard to break down, is easy to manufacture, and can be manufactured at low cost. ■Since there is no need to install the temperature sensor and humidity sensor separately, the installation space and installation effort are halved compared to conventional models. ■Since the device can be made small and thin, it can be installed in small spaces, expanding the range of applications. ■Since temperature and humidity can be measured in the same place, the temperature correction of the humidity sensor's humidity sensitivity characteristics becomes more accurate, making it possible to measure humidity with high precision. ■No special circuit is required for measurement, and measurements can be made using circuits similar to conventional humidity sensor circuits and temperature sensor circuits.

[Brief explanation of the drawing]

FIG. 1 shows the structure of a temperature/humidity sensor according to the present invention, in which (A) is a perspective view and (B) is a longitudinal sectional front view.

FIG. 2 is a diagram showing moisture sensitivity characteristics of the temperature and humidity sensor according to the present invention.

FIG. 3 is a temperature characteristic diagram of the temperature/humidity sensor according to the present invention.

FIG. 4 is a connection diagram showing the configuration of a temperature and humidity measurement circuit using the temperature and humidity sensor of the present invention.

[Explanation of symbols]

1: Moisture sensitive film 2: Metal electrode 3: Counter electrode 4: Wrapping part 5: Common terminal 6: Humidity measurement terminal 7: Temperature measurement terminal 8: Temperature and humidity sensor 10: Temperature measurement circuit 11: Humidity measurement circuit 13: Temperature display 14: Humidity indicator

Claims (4)

[Claims] Claim 1: A metal electrode serving as a first electrode is coated with a moisture sensitive film, and a counter electrode serving as a second electrode is linear, and the metal electrode is coated with a metal electrode so as to be in contact with the moisture sensitive film. A temperature/humidity sensor configured by winding an electrode, characterized in that a linear resistance temperature detector material is used as a counter electrode. 2. The temperature and humidity sensor according to claim 1, wherein the metal electrode is made of stainless steel and the moisture sensitive film is a phosphate film. 3. The temperature/humidity sensor according to claim 1, wherein the resistance temperature detector material is a noble metal wire or a noble metal plated wire. Claim 4: A first metal electrode coated with a moisture-sensitive resistor.
A linear resistance temperature detector material is used as an electrode and a second electrode is used as a counter electrode.
A temperature/humidity sensor is used as an electrode, and the counter electrode is wound around the metal electrode so as to be in contact with the moisture sensitive film of the electrode, and the change in resistance value or the capacitance value between the two electrodes of this temperature/humidity sensor is measured. A method for measuring temperature and humidity using a temperature and humidity sensor, characterized in that humidity is measured by changes in , and temperature is measured by changes in resistance at both ends of a counter electrode.