JPS5930041A - Humidity sensor - Google Patents

Abstract

PURPOSE:To achieve a higher sensitivity by moving a dielectric with the expansion or reduction of a humidity sensitive member expanding or reducing according to the temperature after the mobile dielectric is provided between electrodes facing a capacitance element. CONSTITUTION:Electrode plates 1 and 2 are fixed with a spacer 3 as insulator and a dielectric 4 is inserted therebetween 1 and 2. A spring 5 is fastened at one end of the dielectric 4 and the spacer 3 at the other end of the spring 5. The dielectric 4 is pulled with the spring 5 to be left in the drawing and one end of a humidity sensitive member 6 such as hair is fastened at the other end thereof 4. As the humidity sensitive member 6 expands or reduces according to the humidity, the dielectric 4 moves and the capacitance between the electrodes 1 and 2 varies. This enables the detection of the humidity depending on the variation in the capacitance thereby providing a humidity sensor with a simple construction eliminating the necessity for refreshing.

Description

[Detailed description of the invention] The invention relates to humidity sensors.

2. Description of the Related Art Conventionally, there is a humidity sensor in which a material whose electrical resistance changes depending on humidity is coated on a ceramic substrate, for example, and the resistance value is measured to detect humidity. However, according to this method, there is a large drift due to contamination of the humidity sensing part, and 1fC
It requires a heater to refresh the humidity sensitive part, and has drawbacks such as poor reproducibility.

Therefore, the present invention provides a humidity sensor in which a change in humidity is detected as a change in capacitance by moving a dielectric between electrodes by constructing a humidity sensing member.

Hereinafter, one embodiment of the invention will be described based on the drawings. 1st
In the diagram in Figure 2, reference numerals 1 and 2 are electrode machines, which are fixed with an insulating spacer 3.

A dielectric material 4vi is inserted between the mm plates 1.2, and one end of a spring 5 is fixed to one end of the dielectric material 4vi, and the other end of the spring 5 is fixed to the spacer 3. The spring 5 causes the rope 4 to be pulled to the left in the drawing.

One end of a moisture sensitive member 6 such as hair or a polymeric ribbon is fixed to the other end of the primary dielectric 4, and the other end of the moisture sensitive member 6 is attached to a mounting member (not shown). It is fixed.

Since the moisture sensitive member 6 expands and contracts depending on the humidity, the dielectric 4 moves and the capacitance between the sides 1 and 2 changes. The total humidity can be detected by this change in the chamber.

So, for example, based on the above answer, we decided to use the sweets as the load for the crystal oscillation circuit 7 (7) as shown in Figure 3.

Detect humidity! It can be converted to i1 wave number and extracted.

Ru. In this example, when digitally processing humidity data, the A-D conversion circuit becomes a nuisance.

In the example shown in Figure 5, the inverter is powered by human power.

By configuring both of the two load valleys 11- connected to the output (fltl) as described above, the frequency change can be made largely negative, and the sensitivity can be improved.

In this case, for example, an electric gjA plate 8 as shown in FIG. 4 may be used instead of the electrode plate 1 shown in FIG. 1. This electrode plate 8 has an electrode 10 on an insulating substrate 9. li is formed, with the electrode surface side facing the dielectric material, and the electrode 10. The current visiting body and the counter electrode constitute one for each load, and the electrode 11.
The other load capacity is constructed by constructing the dielectric and the counter electrode.

In each of the above embodiments, when the moisture sensitive member 6 expands, the dielectric material is drawn between the electrodes and the container becomes larger, and the moisture sensitive member 6 contracts. FIG. 5 shows an example of the opposite of this, in which the prizes are drawn out and each prize becomes smaller.

Reference numeral 12 denotes an insulating plate formed in a U-shape, and electrodes 15 and 14 are formed on the inward side of the insulating plate. The dielectric 17, which is tensioned by the spring 15 and the moisture sensitive member 16, is connected to the electrode 13.1.
It is located at a position protruding from the 4-space to the left in the drawing. Therefore, contrary to the above, the capacity decreases and increases as the moisture sensitive member 16 expands and contracts.

Note that each of the capacitive elements described above may be used as a component of an OR oscillator, and the oscillation frequency may be modified to detect humidity.

In addition to using the above area as part of an oscillation circuit to detect humidity using its excavation frequency iK, it is also possible to directly detect the capacitance using a capacity weight meter and convert it to humidity. stomach.

As described in detail above, according to the present invention, a humidity sensor that has a simple configuration and does not require refreshing can be obtained. Especially at pm
By using a tube with a large dielectric constant as the body, a large frequency change can be obtained even with a small displacement of the dielectric material, making it possible to obtain a highly sensitive humidity sensor.

'[7'] (It is possible to detect humidity by using a capacitive element as part of an oscillation circuit and using one at the oscillation frequency.)

When performing digital processing, the A-D conversion circuit 75 becomes unnecessary.

[Brief explanation of the drawing]

Fig. 1 is a front view showing one embodiment of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a cross-sectional view showing an embodiment of the present invention. Electrical circuit diagrams with examples, Part 4
The figure is a front view showing another example of the first fixing part, and FIG. 5 is a sectional view showing another example. 1.2...Electrode plate 4...Dielectric material 6...Moisture sensitive member 8...
... Electrode plate 10, il...11 I pole 13.1
4...Electrode 16...Moisture sensitive member 1
7・・・・・・・・・Dielectric weight Upper Figure 1 Figure 2 □ Figure 8 U

Claims (1)

[Claims] A humidity sensor comprising: a capacitive element with a movable dielectric material between opposing electrodes; and a moisture-sensitive member that expands and contracts in response to humidity.