JPH0453252B2 - - Google Patents

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a humidity detection device.

(b) Prior Art Humidity detectors such as humidity-sensitive ceramics whose electrical characteristics change depending on humidity are known.
This detector utilizes the electrical characteristics of the gas-solid interface, and therefore, the interface is exposed to the atmosphere, susceptible to pollution, etc., and lacks long-term stability. On the other hand, while moisture-sensitive stretchable materials such as hair and nylon as disclosed in Japanese Patent Application Laid-open No. 56-42126 are stable over a long period of time, it is difficult to convert the stretch into electrical signals.

(c) Problems to be Solved by the Invention The present invention provides a humidity detection device that uses a moisture-sensitive expandable body and can easily and sensitively convert the expansion and contraction into an electrical signal.

(d) Means for Solving the Problems The humidity detecting device of the present invention includes a silicon diaphragm type pressure sensor pellet and a moisture-sensitive expandable body that serves as a pressure applying body to the sensor pellet.

(E) Function In the device of the present invention, the moisture-sensitive expandable body expands and contracts depending on the humidity of the atmosphere to be measured, and the pressure sensor pellet converts the expansion and contraction force into an electrical signal.

(f) Embodiment The embodiment device shown in FIG. 1 includes a silicon diaphragm type pressure sensor pellet 1. This pellet is made by utilizing the semiconductor piezo effect in a silicon diaphragm, as is well known from Japanese Patent Publication No. 58-7179. More specifically, the pellet 1 in this example is made of N-type single crystal silicon with a plane of approximately 4 mm square, and includes an annular base 2 of approximately 300 μm in thickness and an annular base 2 of approximately 20 μm in thickness that extends integrally with this base. diaphragm 3. P-type piezoresistive regions 4a to 4d are formed in the diaphragm 3 by diffusion, and wiring paths 5, 5, . . . connected to each region are formed by diffusion or vapor deposition.

The pellet 1 is glued to the head 6 at its base 2, and the lead pins 7, 7 implanted in the header 6
... and the wiring paths 5, 5... of the pellets are connected by a thin metal wire 8.

The moisture-sensitive elastic body 9 has a thickness of approximately several tens of μm to several hundred μm.
The diaphragm 3 of the sensor pellet is attached to the surface of the diaphragm 3 of the sensor pellet using an adhesive such as silicone rubber. Therefore, the expansion and contraction of the moisture sensitive expandable body 9 distorts the diaphragm 3.

A case 10 fixed to the header 6 surrounds the sensor pellet 1, and a gel-like silicone 12 is formed between the case 10 and the surface of the sensor pellet 1, except for the central space containing the opening 11 of the case 10 and the moisture-sensitive elastic member 9. is filled in.

Therefore, when the moisture-sensitive expandable body 9 comes into contact with the atmosphere to be measured through the case opening 11 and expands and contracts according to the humidity, the diaphragm 3 is distorted, and the resistance values of the piezoresistive regions 4a to 4d change accordingly. Each of the piezoresistive regions 4a to 4d is connected to a resistive bridge externally through lead pins 7, 7, . . . as usual, and by reading the output voltage value of this bridge, the skewness of the diaphragm 3, that is, the humidity can be measured.

FIG. 2 shows another example device. In this device, a support 20 fixed to a head 6 is attached to a case 10.
The other end of the moisture sensitive expandable body 9 which extends inward and has one end stuck on the diaphragm 3 is stretched over the support column 20.
Other parts are similar to those in FIG. 1 and are given the same numbers. In this case, the stretching force of the moisture-sensitive stretchable body 9 acts between the struts 20 and the diaphragm 3, and the diaphragm 3 is similarly distorted.

FIG. 3 shows yet another embodiment of the apparatus. In this case, the moisture-sensitive expandable body 9 is placed between the base 2 of the pellet 1 and the head 6, and when it comes into contact with the atmosphere to be measured through the opening 30 of the header 6, it expands and contracts depending on the humidity of the atmosphere. This stretching force is applied to the base 2
is transmitted to diaphragm 3 through it and distorts it.

(g) Effects of the Invention According to the present invention, the moisture-sensitive extensible body stably expands and contracts according to humidity even if it is contaminated by the atmosphere to be measured, and the silicon diaphragm type pressure sensor pellet sensitively transmits electrical signals to the expansion and contraction. Convert to

Therefore, it is possible to provide a humidity detection device with a simple configuration and good performance.

[Brief explanation of the drawing]

FIG. 1A is a sectional view showing the first embodiment of the present invention, FIG. 1B is a plan view of the same essential part, FIG. 2 is a sectional view showing the second embodiment, and FIG. FIG. 2 is a cross-sectional view of main parts showing an example. 1...Pressure sensor pellet, 3...Diaphragm, 9...Moisture-sensitive elastic body.

Claims (1)

[Claims] 1. A humidity detection device comprising a silicon diaphragm type pressure sensor pellet and a moisture-sensitive elastic body that serves as a pressure applying body to the sensor pellet, the moisture-sensitive elastic body being fixed to the pressure sensor pellet.