JPS5934128A - Pressure sensor - Google Patents

Abstract

PURPOSE:To improve the detection sensitivity, by providing resistors, whose resistance values are changed in accordance with strain, in both end parts of a narrow band-shaped arm supporting a pressure receiving part of a pressure receiving diaphragm. CONSTITUTION:The pressure sensor is constituted with a case 18 in which a thick hollow disc-shaped packing 14, a pressure receiving diaphragm 15, a holder 16, a cover 17, and incidence windows 19 and 20 are provided and a measuring component gas is sealed. The pressure receiving diaphargm 15 has a pressure receiving part 28 which is surrounded with space parts 22, 23, and 24 formed by cutting a thin plate such as a quartz plate 21 and is supported by three narrow arms 25, 26, and 27, and resistors consisting of resistance materials such as nickel chromium are stuck to both end parts of the arm 25 by the sputtering technique or the like, when infrared rays are made incident into the case 18, the pressure in the case 18 is increased to press the pressure receiving diaphragm 15 upward in the direction of an arrow, and the arm 25 is deformed to give a strain to resistors, and their resistance values are changed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure sensor that measures a pressure to be measured by receiving the pressure at a pressure receiving part and electrically detecting displacement of the pressure receiving part.

As a conventional example of such a pressure sensor, a condenser microphone, an example of which is shown in FIG. 1, is known. That is, FIG. 1 is an explanatory diagram of the configuration of a well-known infrared gas analyzer, which corresponds to an explanatory diagram of the configuration of a conventional usage example. In the figure, 1 is a sample cell, 2 is a standard cell, 3 is a light source, and 4 is a concave mirror. , 5 is a chopper, 6 and 7 are mirrors, and 8 is a condenser microphone. The condenser microphone 8 also includes a case 11 having light incident windows 9 and 10 and in which a measurement component gas is sealed;
The case 11 is composed of a thin metal film 12 that divides the inside of the case 12 into two, and a fixed electrode 13.The case 11 is configured to detect pressure changes occurring within the case 11 as changes in capacitance between the metal film 12 and the fixed electrode 13. Because it has become. The condenser microphone is excellent in principle as a detector for an infrared gas analyzer, and is particularly often used as a high-sensitivity detector.

However, in the above-mentioned conventional example, when adhering the thin metal film 12, it is necessary to apply tension uniformly to the metal film 12, and non-uniform tension causes variations in sensitivity as a detector. Therefore, there was a drawback that the pasting work required skill. Also, the pasting work required a special jig with a 7'cm length for applying tension.

The present invention has been made in view of this situation, and its purpose is to provide a pressure sensor that has a simple configuration, is easy to assemble, and has high detection sensitivity.

Hereinafter, the present invention will be explained in detail using figures. Second
The figure is a vertical cross-sectional configuration explanatory diagram showing the configuration in a vertical cross section of a pressure sensor according to an embodiment of the present invention, and 0) and (b) in FIG. 0) and (B) in FIG. 4 are an enlarged cross-sectional view and an enlarged plan view of the part A (or B) in FIG. 3 (B), and FIG. FIG. 2 is a displacement detection circuit wiring diagram for detecting displacement. In FIGS. 2 and 3, 14 is a thick hollow disc-shaped packing having an appropriate thickness (for example, several M), 15 is a pressure receiving diaphragm,
16 is a holder, 17 is a cover, and 18 is a case that is integrated with the holder 16 and has, for example, a light entrance window 19, 20, and a gas to be measured is sealed inside.

The pressure-receiving diaphragm 15 is made of a thin plate, for example, a crystal plate 21 with a thickness of 501 Jm (which may be made of glass, sapphire, silicon, etc.), using photo-phosphorography technology, as shown in FIG. It is comprised of a pressure receiving part 28 surrounded by cutout-shaped cavities 22, 23 and 24 of a predetermined shape and supported by three thin arms 25, 26 and 27.

Further, the pressure receiving diaphragm 15 is housed in a holder 16 so as to be pressed by a packing 14. Furthermore,
In FIGS. 4(A) and 4(B), which are an enlarged sectional view and an enlarged plan view of part A (or part B) in FIG. 5(b), predetermined portions at both ends of the arm 27 (or 25) are shown. Two resistors 29a and 29b (or two resistors 311IL and 31b) made of a resistive material such as nickel chromium are attached to the resistor by sputtering technique or the like. Moreover, the resistors 29a and 29b (
or two resistors 31a and 31b) as shown in FIG.
As shown in b), the wires are connected by wire connection patterns 31a to 31c (or 32a to 32c) to form a bridge as shown in FIG. The shape of the pressure receiving part 28 in the present invention is not limited to the above-mentioned square shape, but may be circular or triangular, and the number of the cavities 22, 23 and 24 and the arms 25, 26 and 27 may also be three. The number is not limited to , and any number of numbers may be used.

The operation of the embodiment of the present invention having the above configuration will be described below. In FIG. 2, when infrared rays pass through the light input/output windows 19 and 20 and enter the case 18, and the pressure inside the case 1B increases and the pressure receiving diaphragm 15 is pushed up in the direction of the arrow, the pressure receiving diaphragm 15 is placed under pressure fluctuations, and the pressure receiving portion 28 in FIG. 3 begins to vibrate. By the way, the pressure receiving part 28 is photographed, and the arm 27 (or arm 25) (hereinafter simply referred to as "arm part") is moved as shown in FIG.
Assuming that the arm is deformed as shown in b), the length of the arm is t
, a constant determined by the cross-sectional shape of the arm and the magnitude of force, and the displacement of the pressure receiving part 28 as X, the amount of deformation δ of the arm is expressed as in the following equation (1). It will be done.

Further, the moment N1 of movement in the arm is expressed as in the following equation (2).

Therefore, no strain occurs in the center of the arm, but moments M with different polarities act on both ends of the arm, causing strain ε as shown in equation (5) below on the surface of the arm. It becomes like this.

However, 2 is the section modulus of the arm (5), i.e., resistor 29a (30a) and 29 in FIG.
b (30b), so that strains with opposite signs such as tensile strain and compressive strain occur, and the resistance values of resistors 29a (30a) and 29b (30b) are increased by multiplying the strain by the gauge factor. It starts to change. Therefore, by adopting the bridge configuration as shown in FIG. 5, an electric signal proportional to the displacement of the pressure receiving portion 28 can be obtained between each terminal 31c and 32c.

According to the embodiment of the present invention as described in detail above, since the packing 14 and the pressure receiving diaphragm 15 are housed in the boulder 16, there is an advantage that the assembly work is easy. Further, compared to the conventional example, since a back plate such as the fixed electrode 13 is not required, there is also an advantage that the structure is simpler. Furthermore, since the pressure receiving diaphragm 15 can be made of a thicker material than the metal film 12 of the conventional example, it is suitable for mass production, the price is low, and the characteristics can be easily made uniform, so it is ultimately suitable for pressure sensors. It also has the advantage of improving reliability.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the usage example of the conventional example, Figure 2 is a vertical cross-sectional configuration diagram of the embodiment of the present invention, Figure 3 is an explanatory diagram of the main parts configuration of the embodiment of the present invention, and Figure 4 is Figure 3. (b) Enlarged explanatory diagram of the main parts,
FIG. 5 is a circuit connection diagram for detecting displacement of the pressure receiving part. 1... Sample cell, 2... Standard cell, 4... Concave mirror, 5... Chopper, 6, 7... Mirror, 8... Condenser microphone, 9.10.19.20...・Light incidence window, 11. 18... Case, 12... Metal film, 13... Fixed electrode, 14... Packing, 15...
・Pressure diaphragm, 16... holder, 17...
Cover, 22-24. 22'-24'...Gap, 2
5-27...Arm, 28...Pressure receiving part 529a, 29b
, 30a, 30'ly'' resistor, 31a to 31c. 32a to 32c... Wiring pattern.

Claims (3)

[Claims] (1) A pressure-receiving part that is made of a thin plate-like member as a base material and is surrounded by a plurality of narrow strip-shaped voids and is displaced in accordance with the applied pressure to be measured, and predetermined portions of each two of the voids. A pressure-receiving diaphragm is provided in a predetermined container, and includes a plurality of resistors, which are surrounded by a plurality of resistors and are attached to the pressure-receiving part and whose resistance value changes by producing a predetermined strain in accordance with the deformation of the arm. A pressure cassette/sample, characterized in that the pressure to be measured is measured by electrically detecting a value change. (2) The electrical detection is performed by configuring the plurality of resistors in a predetermined bridge shape, and detecting a change in current flowing through the bridge-shaped electric circuit. pressure sensor. (3) The pressure sensor according to claim (1) or (2), wherein the resistor is made of nickel chromium.