JPS61202152A - Moisture detector - Google Patents

Abstract

PURPOSE:To obtain a highly sensitive moisture detector which can convert the stretching force of a moisture-sensitive body stably though it is contaminated, by joining such a moisture-sensitive body as being stretchable according to moisture on a silicon diaphragm type pressure sensor pellet as pressure applying factor to the pellet. CONSTITUTION:A silicon diaphragm type sensor pellet 1 having a diaphragm section 3 about 20 mum thick and a circular base section 2 about 300mum thick is formed from an n-type monocrystaline silicon in such a manner that p-type piezo-electric resistance areas 4a-4d are made at the diaphragm 3 by diffusion while wiring paths 5, 5... following the areas are made by evaporation or the like. The base section 2 of the pellet 1 is adhered to a header 6 and lead pins 7, 7... provided on the header 6 and wiring circuits 5, 5... are connected together with a fine metal wire 8. A moisture- sensitive stretching body 9 about several tens-several hundreds mum made of nylon is joined on the diaphragm 3 and the pellet 1 is wrapped with a case 10 by filling the portion with a gelatinous silicon 12 except for the central space including an opening 11 and the moisture-sensitive body 9. Thus, a stable stretching force of the stretching body 9 can be converted into an electrical signal sensitively with a pellet 1 free from contamination due to atmosphere to be measured.

Description

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

(b) Conventional technology Humidity detectors, such as humidity-sensitive ceramics, whose electrical characteristics change depending on humidity are known.

This detection body utilizes the electrical characteristics of the gas-solid interface, and therefore, the interface is exposed to the atmosphere, susceptible to the effects of pollution, etc., and lacks long-term stability. In contrast,
As disclosed in Japanese Unexamined Patent Publication No. 56-42126, moisture-sensitive stretchable materials such as hair and nylon are stable over a long period of time, but it is difficult to convert their 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.

B) Means for Solving the Problems The humidity detection 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 in accordance with the humidity of the ambient air 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 (1). This bellet itself is well known from Japanese Patent Publication No. 58-7179, etc.
This utilizes the semiconductor piezo effect in a silicon diaphragm. The beret (1) in this example is:
More specifically, it consists of an annular base (2) made of N-type single crystal silicon with a plane of approximately 4FF angle and approximately 600 μm thick, and a diaphragm (31) approximately 20 μm thick that is integrally connected to this base. P-type piezoresistive regions (4a) to (4d) are formed in the diaphragm (3) by diffusion, and the wiring paths (5i (51...) connected to each region are formed by diffusion or vapor deposition. It is formed of.

The bellet (1) has a header (6) at its base (2)
The lead bin (7) is glued to the header (6) and embedded in the header (6).
A metal #jB wire (8) connects 071... and the bullet wiring path (51(5)...).

The moisture-sensitive elastic body (9) is made of nylon and has a thickness of about several tens of micrometers to several tens of micrometers, and is adhered to the surface of the diaphragm (3) of the sensor pellet with an adhesive such as silicone rubber. Therefore, the expansion and contraction of the moisture-sensitive elastic body (91) is the diaphragm (3
) to distort.

The case (10, fixed to the header (6) surrounds the sensor pellet (1), and the case α0.
Gel-like silicon Q2i is buried between the sensor pellet (1) and the surface of the sensor pellet (1).

Therefore, when the moisture-sensitive extensible body (9) comes into contact with the atmosphere to be measured through the case opening (1)) 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 piezoresistive region (4a) to (4d) is, as usual,
A resistance bridge is connected externally through lead bins (71 (7)...), and by reading the output voltage value of this bridge, the distortion of the diaphragm (3), that is, the humidity can be measured.

FIG. 2 shows another example device. In this device, a strut (4)) fixed to a header (6) extends into a case (10) and has a moisture-sensitive elastic body (9) affixed at one end onto a diaphragm (3).

The other end is hung on a support post. Other parts are first
It is similar to the figure and has the same number.

In this case, the elastic force of the moisture-sensitive elastic body (9+) acts between the strut and the diaphragm (3), and similarly the diaphragm (3)
3) is distorted.

FIG. 6 shows yet another embodiment of the apparatus. In this case, the moisture-sensitive elastic body (91 is the base (2) of the bellet (1) and the header (6)
By contacting the atmosphere to be measured through the opening of the header (6), it expands and contracts depending on the humidity of the atmosphere. This expansion and contraction force is applied to the diaphragm (3) through the base (2). It is transmitted to the body and distorts the fidgets.

(G) Effects of the Invention According to the present invention, the moisture-sensitive extensible body stably does not expand or contract according to humidity even if it is contaminated by the atmosphere to be measured, and the silicon diaphragm type pressure sensor pellet sensitively controls the expansion or contraction by electrically controlling the expansion or contraction. Convert to signal.

[Brief explanation of drawings]

FIG. 1A is a cross-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 cross-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, (31...
...Diaphragm, (9) ...Moisture-sensitive elastic body.

Claims (1)

[Claims] (1) Silicon diaphragm heavy pressure sensor pellet,
A humidity detection device comprising a moisture-sensitive expandable body that applies pressure to the sensor pellet.