JPH04143648A - humidity sensor - 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 [Field of Industrial Application] The present invention relates to a humidity sensor that detects temperature by changing the electrical characteristics of an element in response to humidity.

[Conventional technology] In recent years, the number of fields requiring humidity measurement and humidity control has increased.
The importance of humidity sensors is now recognized.

Humidity sensors that detect humidity by changing the electrical characteristics of the element in response to humidity include electrolyte-based, metal-based, polymer-based, ceramic-based, etc., and various systems are being researched. , those currently in practical use are:
These are polymer-based and ceramic-based humidity sensors. All of these utilize the property that the resistance value or capacitance of the element changes due to adsorption and desorption of water to the element.

[Problems to be Solved by the Invention] However, since the conventional humidity sensor has a high resistance value, advanced circuit technology and mounting technology are required in order to manufacture a thermometer with high accuracy.

The present invention is intended to solve these problems, and its purpose is to provide a temperature sensor with low resistance, high accuracy, and high reliability.

[Means for Solving Problem Y] The humidity sensor of the present invention is characterized in that a heat-treated product of a lithium salt solution in which silica particles are dispersed is used as a temperature sensor.

[Example 1 Cotetraethoxysilane (Si(○C2H3L) 50ml
40 ml of 0.02N hydrochloric acid and 15 g of finely powdered silica were added thereto, and after stirring for 1 hour, 20 g of lithium chloride was added to prepare a lithium salt solution in which silica particles were dispersed. Aqueous ammonia was added to this solution to form a gel, and after drying at 60°C for 2 days, heat treatment was performed at 800'C for 1 hour to produce a heat-treated product of a lithium salt solution in which silica particles were dispersed. 10mm x 10mm x from this heat treated product
A 5 mm rectangular parallelepiped was cut out, electrodes were attached, and the humidity sensor shown in FIG. 1 was produced.

FIG. 1 shows a perspective view Z of the humidity sensor manufactured in this manner. In FIG. 1, 1 is a humidity sensing element, 2 is an electrode, and 3 is a lead wire. Figure 2 shows the humidity sensitivity characteristics of this humidity sensor. From FIG. 2, the humidity sensor of the present invention has a low resistance value;
You will find it easy to use.

[Example 2] 25 ml of ethanol was added to 25 ml of water, and 15 g of finely powdered silica and 15 g of lithium chloride were added to prepare a lithium salt solution in which silica particles were dispersed. This solution was dip-coated on an alumina substrate on which a Pt-Pd comb-shaped electrode was formed by screen printing, and then heated at 100°C for 1 hour.
After drying for 0 minutes, heat treatment was performed at 500° C. for 30 minutes to form a heat-treated product of a lithium salt solution in which silica particles were dispersed.

FIG. 3 shows a perspective view of the humidity sensor manufactured in this manner. In FIG. 3, 1 is a moisture sensitive film, 2 is an electrode, and 4 is a substrate. Figure 4 shows the humidity sensitivity characteristics of this humidity sensor. From FIG. 4, it can be seen that the humidity sensor of the present invention has a low resistance value and its characteristics do not change depending on temperature, so it is highly accurate and easy to use. This humidity sensor is heated to 60°C90
After being left in a constant temperature and humidity chamber for 1000 hours, the characteristics were measured and found to be the same as in FIG. 4 within the range of measurement error.

Therefore, it can be seen that this humidity sensor has high durability and reliability.

[Effects of the Invention] As described above, the humidity sensor of the present invention uses a heat-treated product of a lithium salt solution in which silica particles are dispersed as a humidity sensitive element, so the resistance value is low and the characteristics do not change depending on temperature. Therefore, advanced circuit technology and mounting technology are not required, and it is highly accurate, easy to use, and highly reliable. Therefore, as a low-cost, high-precision humidity sensor, it can be widely applied to fields requiring humidity measurement and humidity control.

[Brief explanation of the drawing]

1 and 3 are perspective views of the humidity sensor of the present invention. 1...Moisture sensitive body or moisture sensitive membrane 2...electrode Lead substrate Figure 2, The fourth side is Humidity sensitivity of the humidity sensor of the present invention Characteristic diagram. that's all

Claims (1)

[Claims] A humidity sensor characterized in that a heat-treated product of a lithium salt solution in which silica particles are dispersed is used as a humidity sensor.