JPH10111206A - Capacitive pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable application to high pressure detection, and simultaneously realize the simplification of structure and improvement of reliability to life. SOLUTION: In a housing 11 formed of metal, a cylindrical housing main body part 12 having a pressure receiving port 12a and a diaphragm part 13 facing the pressure receiving port 12a are collectively installed in an unified body. A board 14 formed of ceramic has a circular detecting electrode 15 which faces the diaphragm part 13 in the state that a specified gap exists, and an annular reference electrode 16 which faces the peripheral part position of the housing main body part 12, having the same gap. A detecting capacitor CD whose capacitance is changed in accordance with deformation of the diaphragm part 13 is formed between the upper surface of the diaphragm part 13 and the detecting electrode 15. A reference capacitor CR whose capacitance becomes constant is formed between the upper part of a trapezoid part 12d and the reference electrode 16. An LSI 19 for a processing circuit detects the pressure acting on the diaphragm part 13, on the basis of the deviation of the respective capacitances of the detecting capacitor CD and the reference capacitor CR.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type pressure sensor which is configured to take out deformation of a diaphragm portion in response to pressure application as a change in capacitance, and is particularly suitable for use in detecting a high pressure. The present invention relates to a capacitance type pressure sensor.

[0002]

2. Description of the Related Art An electrostatic capacitance type pressure sensor of this type basically has a first detection electrode (movable electrode) provided on a diaphragm arranged to receive pressure from a fluid to be subjected to pressure detection.
And a second detection electrode (fixed electrode) facing the detection electrode with a predetermined gap therebetween, so that the capacitance between the two electrodes changes due to deformation of the diaphragm. Is used to detect pressure.

FIG. 4 shows an example of a capacitance type pressure sensor having such a configuration. In FIG. 4, a movable ceramic substrate 2 on which a diaphragm and a movable electrode (both not shown) are formed in a metal housing 1 and a gap of about 10 to 17 μm from the movable electrode. And the fixed-side ceramic substrate 3 on which the fixed electrodes (not shown) are formed. In this case, a pressure receiving chamber 5 sealed by, for example, an O-ring 4 made of rubber is formed between the bottom of the metal housing 1 and the movable ceramic substrate 2. At the bottom of the metal housing 1,
A cylindrical mounting member 6 having a pressure receiving port 6a communicating with the pressure receiving chamber 5 is connected. The mounting bracket 6 is connected to a pressure detection target portion via a screw groove (not shown) formed in an inner peripheral portion, and thereby a diaphragm portion formed on the movable ceramic substrate 2 is formed. Against
The pressure is applied through the pressure receiving port 6 a and the pressure receiving chamber 5.

The metal housing 1 houses a circuit board 8 on which a group of circuit elements 7 including a processing circuit for detecting a change in capacitance between the movable electrode and the fixed electrode is mounted. The metal housing 1 houses a base of a connector 9 for supplying power and taking out an output signal, and a seal member 10 is provided between the connector 9 and the metal housing 1.

[0005]

The capacitance type pressure sensor constructed as described above has advantages such as a relatively simple structure, and is expected to be developed for various uses. . However, in the conventional capacitance type pressure sensor, the pressure resistance is relatively low due to the sealing of the pressure receiving chamber 5, that is, the closed space required for applying the pressure to the diaphragm portion (the highest pressure sensor is used). Since the use of the O-ring 4 having a restriction of about 200 atm is an essential component, there is a problem that its use is limited to low pressure use.

Particularly, in recent years, there has been an increasing need for a pressure sensor capable of detecting a high pressure of about 1500 atm for detecting an injection pressure in a fuel injection pump of a diesel engine, for example. With a pressure sensor of the type, it is completely impossible to apply it to such applications, and this has been an unsolved problem. In the seal structure using the O-ring 4 as described above,
There is also a problem that the reliability with respect to the life is reduced due to the deterioration of the O-ring 4 and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has as its object to be applicable to applications for detecting high pressure, to simultaneously simplify the structure and to improve reliability with respect to life. An object of the present invention is to provide a capacitance-type pressure sensor which has effects such as realization.

[0008]

According to the first aspect of the present invention, since the diaphragm portion made of metal functions as a movable electrode, a predetermined gap is formed between the diaphragm portion and the diaphragm portion. In this state, a capacitor is formed between the detection electrode and the detection electrode which is disposed to face. For this reason, when pressure acts on the diaphragm through the pressure receiving port into which the fluid to be subjected to pressure detection enters, the capacitance between the diaphragm and the detection electrode changes in accordance with the deformation of the diaphragm accompanying the pressure. Thus, the pressure acting on the diaphragm can be detected based on such a change in capacitance.

In this case, since the above-mentioned diaphragm is formed integrally with the metal housing main body having the pressure receiving port, the diaphragm for applying pressure to the diaphragm is closed. It is not necessary to provide a conventional sealing structure using an O-ring in order to form the space. As a result, a configuration capable of detecting a high pressure can be easily realized, and there is no danger that the reliability with respect to the life is reduced due to the deterioration of the seal structure. In addition, by providing a metal housing in which the housing body and the diaphragm are integrally formed, the diaphragm can be used as a movable electrode, and a seal structure using a separate component can be eliminated. Simplicity can be achieved at the same time.

According to the second aspect of the present invention, after the detection electrode is formed on the substrate, the substrate is fixed to the housing via the spacer, thereby setting the gap size between the diaphragm and the detection electrode. With this configuration, the gap size can be easily managed.

According to the third aspect of the present invention, the substrate on which the detection electrodes are formed is bonded and fixed to the metal housing with a flexible adhesive (that is, an adhesive having a small Young's modulus). Strain stress generated between the substrate and the housing due to the difference in the coefficient of thermal expansion between them is absorbed and reduced by the flexible adhesive portion. As a result, stabilization of output characteristics and the like can be realized.

According to the fourth aspect of the present invention, the spacer for setting the gap between the diaphragm and the detection electrode is formed by a plurality of resin beads mixed with the above-mentioned flexible adhesive. Therefore, the gap size can be strictly and easily managed. In addition, since the resin beads have a property of having a relatively small Young's modulus, there is no possibility that the presence of the resin beads impairs the stress relaxation function of the flexible adhesive.

According to the present invention, the pressure acting on the diaphragm is detected based on the deviation between the capacitance between the diaphragm and the detection electrode and the capacitance between the housing body and the reference electrode. Even if the capacitance between the diaphragm and the detection electrode fluctuates due to an assembling error, etc., the fluctuation is similarly changed between the housing body and the reference electrode. The offset can be achieved by the capacitance, and as a result, the pressure detection accuracy can be improved.

According to the sixth aspect of the present invention, the initial value of the capacitance between the diaphragm and the detection electrode can be set to be equal to the initial value of the capacitance between the housing body and the reference electrode. In such a state, it is possible to simplify the configuration of the processing circuit for canceling the variation in the capacitance between the diaphragm and the detection electrode by the variation in the capacitance between the housing body and the reference electrode. Become.

According to the seventh aspect of the present invention, since the fixed portion between the substrate and the housing is located at the position between the detection electrode and the reference electrode on the substrate, the detection pressure acts on the housing. Even when distortion occurs in the main body, it is possible to minimize the situation where the gap dimension between the housing main body and the detection electrode changes due to the influence of the distortion. Further, displacement of the substrate due to disturbance such as vibration can be easily suppressed. As a result, the function of canceling the above-described variation in the capacitance between the diaphragm portion and the detection electrode by the variation in the capacitance between the housing body and the reference electrode can always be sufficiently exerted, and the pressure can be sufficiently reduced. The detection accuracy is improved.

According to the present invention, the surface of the diaphragm opposite to the pressure receiving surface, that is, the portion functioning as the movable electrode, and the surface of the housing main body facing the reference electrode, that is, a pair. Since the surface functioning as one side of the reference electrode is formed to be flush with the surface, the processing (cutting, polishing, etc.) of the metal housing necessary for forming the electrodes can be easily performed. As a result, the manufacturability is improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1 showing the entire vertical cross-sectional structure, a metal housing 11 is
It has a structure in which a cylindrical housing body 12 provided with a pressure receiving port 12a into which a fluid to be subjected to pressure detection enters, and a circular diaphragm portion 13 positioned so as to face the pressure receiving port 12a. That is, the diaphragm portion 13 is provided in a form in which the upper portion of the cylindrical housing main body portion 12 is closed, so that the lower surface of the diaphragm portion 13 functions as a pressure receiving surface. In this embodiment, the housing 11 is formed by subjecting a metal material having a high yield resistance, such as stainless steel (for example, SUS630) or high carbon steel (for example, S45C), to cutting and polishing. I have.

On the outer periphery of the housing main body 12, a screw portion 12b for screwing into a mounting opening (not shown) formed in the pressure detection target portion is engraved. A flange portion 12c having a hexagonal cross section used for tightening the screw portion 12b is formed on the head.

The upper part of the housing 11 has a flange 1
A trapezoidal portion 12d smaller in diameter than 2c is formed, and a ceramic substrate 14 is bonded and fixed on the trapezoidal portion 12d with a predetermined gap between the substrate 14 and the trapezoidal portion 12d. .

Here, FIG. 2 schematically shows a longitudinal sectional structure of the housing 11 and the substrate 14, and will be described below with reference to FIG. That is, the substrate 14
Is formed in a flat plate shape, and has on its lower surface a circular detection electrode 15 opposed to the upper surface of the diaphragm portion 13 (surface opposite to the pressure receiving surface) with a predetermined gap,
An annular reference electrode 1 which is opposed to a peripheral portion of the trapezoidal portion 12d with a gap having the same size as the above gap.
6 are formed concentrically. In addition, it is configured such that a predetermined insulation distance exists between the detection electrode 15 and the reference electrode 16.

As a result, between the upper surface of the metal diaphragm portion 13 and the detection electrode 15, the diaphragm portion 13
A detection capacitor CD whose capacitance changes in accordance with the deformation of the detection electrode 15 (increases in accordance with the deformation close to the detection electrode 15) is formed, and the upper surface of the metal housing body 12 (the trapezoidal portion 12d) is also formed. A reference capacitor CR having a constant capacitance is formed between the reference capacitor 16 and the reference electrode 16.

Therefore, the pressure acting on the diaphragm 13 can be detected based on the capacitance of the detection capacitor CD. In this case, the diaphragm 1
The diameter and thickness of 3 are determined according to the magnitude of the pressure to be detected. For example, the diameter is set to 4 to 8 mm, and the thickness is set to 0.4 to 3 mm. As a result, it is possible to detect a pressure from several tens of atmospheres to about 3000 atmospheres.

More specifically, when the material of the housing 11 is the above-mentioned high yielding resistance metal material, the diameter of the diaphragm portion 13 is set to 8 mm and the thickness is set to 0.6 mm so that 100 atmospheres is obtained. To the extent detectable.
Further, by setting the diameter of the diaphragm 13 to 4 mm and the thickness to 3 mm, it is possible to detect up to about 3000 atmospheres. However, in this embodiment, the diameter of the diaphragm 13 is set to 6 mm and the thickness thereof is set to 1.7 mm in order to detect a pressure of about 1500 atm.

In this embodiment, each area of the detection electrode 15 and the reference electrode 16 is set to be equal to each other and slightly less than 0.3 cm ² , and the diaphragm 13 and the detection electrode 15
, And the trapezoid 12d and the reference electrode 16
Are set to be approximately 75 μm, so that the capacitances of the detection capacitor CD and the reference capacitor CR are approximately 3.3 pF. Specifically, the diameter of the detection electrode 15 is 6 mm (same as the diameter of the diaphragm 13), and the inner and outer diameters of the reference electrode 16 are 12 mm and 1 mm, respectively.
By setting it to 3.42 mm, these electrodes 15 and 1
The area of No. 6 is set to be less than 0.3 cm ² .

In the present embodiment, the upper surface of the trapezoidal portion 12d is formed in a planar shape, whereby the configuration described in claim 8 (the surface opposite to the pressure receiving surface of the diaphragm portion 13 and the housing body portion). 11 in which the surface facing the reference electrode 16 is flush with the reference electrode 16).

The bonding between the trapezoidal portion 12d and the substrate 14 is performed at a position between the detection electrode 15 and the reference electrode 16 on the substrate 14. In this case, a plurality of resin beads 17 as spacers are used for the bonding.
A flexible adhesive 18 having a small Young's modulus is used, and the adhesive 18 has a ring shape surrounding the detection electrode 15. That is, resin beads 1
By selecting the diameter of 7, the gap size between the upper surface of the diaphragm portion 13 and the detection electrode 15 and the gap size between the reference portion 16 and the peripheral portion of the trapezoidal portion 12d are set. . In general, the resin beads have a small Young's modulus, but the resin beads 17 used in this embodiment may have a Young's modulus as close as possible to the Young's modulus of the flexible adhesive 18. desirable.

An LSI 19 (bare chip) for a processing circuit is die-bonded on the upper surface of the substrate 14 in order to minimize the noise due to the vibration in order to reduce the weight of the components on the substrate 14. The processing circuit LSI 19 has a function of detecting the pressure acting on the diaphragm 13 based on the deviation of the respective capacitances of the detection capacitor CD and the reference capacitor CR. Bonding wire 2 for pattern 14a group
0. The conductive pattern 14
a is connected to the detection electrode 15 and the reference electrode 16 via a through hole formed in the substrate 14. Further, the substrate 14 has an air vent hole (not shown) for communicating a space formed between the diaphragm 13 and the detection electrode 15 with the outside (it can also be used as a through hole for each of the electrodes 15 and 16). Is formed.

Returning to FIG. 1, a holder 21 made of a resin such as PBT (polybutylene terephthalate) is arranged on the trapezoidal portion 12d of the housing 11 so as to cover the substrate 14. The connector terminal 22 is provided on the holder 21 by, for example, insert molding. The connector terminal 22 is provided for supplying power to the processing circuit LSI 19 and extracting an output signal from the LSI 19, and when the power supply side and the output signal extracting side share the ground terminal, Three (only one is shown in FIG. 1) are prepared.

In this case, the base of the connector terminal 22 is connected to one end of a lead wire 23 made of a flexible conductive material, for example, in the form of a strip. This lead wire 23 is formed on the holder 21. The substrate 1 is inserted into the through hole 21a and the intermediate portion is bent.
4 is connected to the conductive pattern 14a (see FIG. 2). Further, a connector housing 24 made of, for example, PBT is arranged on the holder 21 in a stacked manner, and the connector terminal 22 is connected to the connector housing 24.
Is projected into the connector housing 24 while penetrating the bottom of the connector housing 24.

The holder 21 and the connector housing 24 as described above are integrated by a metal ring 25 provided so as to cover the periphery of the holder 21 and the connector housing 24. It is connected to the upper surface by welding and its upper edge is swaged. Thereby, the housing 11, the holder 21, the connector housing 24 and the like are integrated. An O-ring 26 is provided between the peripheral edges of the connector housing 24 to prevent moisture or the like from entering.

According to the configuration of the present embodiment, as described above, the electrode is formed between the upper surface of the metal diaphragm portion 13 which receives pressure through the pressure receiving port 12a and the detection electrode 15 on the substrate 14 side. The pressure acting on the diaphragm 13 can be detected based on the detected capacitance of the detection capacitor CD.

In this case, since the diaphragm portion 13 is formed integrally with the metal housing main body portion 12 having the pressure receiving port 12a, a closing portion for applying pressure to the diaphragm portion 13 is provided. It is not necessary to provide a conventional seal structure using an O-ring (indicated by reference numeral 4 in FIG. 4) in order to form the space. As a result, a configuration capable of detecting a high pressure of 1500 atm as in the present embodiment can be easily realized, and there is no possibility that the reliability with respect to the life is reduced due to the deterioration of the seal structure portion. In addition, the metal diaphragm 13 can be used as a movable electrode necessary for forming the detection capacitor CD, and a seal structure using separate components can be eliminated, so that the structure can be simplified at the same time. become.

The housing body 12 (the trapezoidal portion 12)
A reference capacitor CR having a constant capacitance is formed between the upper surface of d) and the reference electrode 16 provided on the substrate 14. Then, the reference capacitor CR as described above is supplied to the processing circuit LSI 19. Based on the deviation between the capacitance of the detecting capacitor CD and the capacitance of the detecting capacitor CD.
Since the function of detecting the pressure acting on the surface is provided, the following effects can be obtained. In other words, even when the gap size between the diaphragm 13 and the detection electrode 15 fluctuates (when the capacitance of the detection capacitor CD fluctuates) due to an assembling error or the like, the fluctuation is similarly reduced. The fluctuation can be offset by the fluctuation of the gap size between the housing body 11 and the reference electrode 16 (the fluctuation of the capacitance of the reference capacitor CR), and as a result, the pressure can be detected accurately. Become. Of course, even if the capacitance of the detection capacitor CD fluctuates due to temperature drift or the like, the fluctuation can be offset by the fluctuation of the capacitance of the reference capacitor CR.

In this case, the detection electrode 15 and the reference electrode 16
, The gap dimension between the diaphragm 13 and the detection electrode 15 and the gap dimension between the housing body 11 and the reference electrode 16 are set to be equal to each other.
The initial value of the capacitance of the detection capacitor CD can be set equal to the initial value of the capacitance of the reference capacitor CR. In this state, the detection capacitor C
Since the circuit configuration for canceling the variation in the capacitance of D by the variation in the capacitance of the reference capacitor CR does not become complicated, the configuration of the processing circuit LSI 19 can be simplified.

Further, a plurality of resin beads 17 functioning as spacers are formed on a ceramic substrate 14 on which a detection electrode 15 and a reference electrode 16 are formed, with respect to a trapezoidal portion 12 d formed on the housing body 12. Since the adhesive is fixed by the compounded flexible adhesive 18, the gap between the diaphragm 13 and the detection electrode 15 and the gap between the housing body 12 and the reference electrode 16 can be strictly and easily managed. And the output characteristics can be stabilized.

Further, when the flexible adhesive 18 is used for fixing between the ceramic substrate 14 and the metal housing body 12 as described above, the substrate 14 and the housing body 12 Since the strain stress generated between the two due to the difference in the coefficient of thermal expansion is absorbed and relaxed by the flexible adhesive 18, the output characteristics can be further stabilized. In this case, the flexible adhesive 18
Is a state in which resin beads 17 as a spacer are compounded. As the resin beads 17, those having a Young's modulus as close as possible to the Young's modulus of the flexible adhesive 18 are used. Therefore, there is no possibility that the resin beads 17 hinder the stress relaxation function of the flexible adhesive 18.

The lead wire 23 connecting the board 14 and the connector terminal 22 is also flexible, and has a structure in which a part thereof is bent.
However, there is no possibility that unnecessary distortion is applied through the lead wire 23.

In this embodiment, the upper surface of the diaphragm portion 13 (the surface opposite to the pressure receiving surface), that is, the portion functioning as the movable electrode of the detection capacitor CD, and the housing body portion 12
Is formed so that the surface facing the reference electrode 16 in the above, that is, the surface functioning as one electrode for the reference capacitor CR, is flush with the metal housing 11 necessary for forming these electrodes. (Cutting, polishing, etc.) can be easily performed, and the manufacturability is improved. In addition, the trapezoidal portion 12d is formed such that a part of the surface protrudes from the upper surface of the housing body 12.
, The processing of the metal housing 11 as described above can be performed more easily.

Further, the detection electrode 1 is provided on the substrate 14.
5 and the reference electrode 16, and a fixed distance between the trapezoidal portion 12 d of the housing body 12 and the substrate 14 is fixed to the detection electrode 1 on the substrate 14.
5 and the reference electrode 16, the reference electrode 16 can be located in the peripheral portion of the housing body 12. According to such a configuration,
Even when distortion occurs in the housing main body 12 due to the application of a large detection pressure, a situation in which the gap dimension between the housing main body 12 and the reference electrode 16 changes due to the influence of the distortion can be minimized. .
Further, displacement of the substrate 14 due to disturbance such as vibration can be easily suppressed. As a result, as described above, the function of canceling the change in the capacitance of the detection capacitor CD by the change in the capacitance of the reference capacitor CR can be sufficiently exerted at all times, so that the pressure detection accuracy can be improved. Become.

FIG. 3 shows a state in which pressure is applied to the housing 11 through the pressure receiving port 12a.
The result of analyzing how much displacement occurs on the upper surface of the housing 11 is shown. However, this analysis assumes a state in which the housing main body 12 is screwed into a mounting opening formed in the pressure detection target portion (a state in which the displacement of the housing main body 12 in the radial direction is restrained). In FIG. 3A, the direction of the pressure applied to the housing 11 schematically shown only in the right half is indicated by an arrow (“A” in the figure indicates the radial direction of the housing body 12). The constraint means for restraining the displacement of the is shown). FIG. 3B shows a state where the magnitude of the displacement generated on the upper surface of the housing 11 is associated with the distance from the center O of the diaphragm 13. FIG.
FIG. 3C is a perspective view of the substrate 14 viewed from below in order to clarify the correspondence between the positions of the detection electrode 15 and the reference electrode 16 and the distance from the center O of the diaphragm 13. ing.

FIG. 3 shows that at the position corresponding to the reference electrode 16 on the housing 11 (position within a range of 6 mm to 6.71 mm from the center O of the diaphragm 13), the displacement generated on the upper surface of the housing 11 is the same. It can be seen that the level is lower than the limit level shown as an example by a broken line in the figure. Further, it can be seen that the displacement at the diaphragm portion 13 is larger than the required minimum level shown as an example by a two-dot chain line in FIG.

The present invention is not limited to the above-described embodiment, but can be modified or expanded as follows. Although a metal material having a large yield resistance is used as the material of the housing 11, such a configuration is not always necessary, and a material having a general-sized yield resistance (for example, carbon steel such as S15C) is used. May be used. A configuration in which the substrate 14 is not required, that is, a configuration in which a single detection electrode is disposed to face a surface opposite to the pressure receiving surface of the diaphragm with a predetermined gap therebetween is also possible. As the flexible adhesive 18, silicone resin, urethane resin, acrylic resin, polyamide resin, polyimide resin,
A material having a small Young's modulus such as a flexible epoxy resin can be widely used. Also, the resin beads 17 can be selected from various materials such as polydinivirbenzene resin, silicon resin, urethane resin, and acrylic resin.

[Brief description of the drawings]

FIG. 1 is an overall vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view schematically showing a configuration of a main part.

3A and 3B are diagrams for explaining a result of analyzing a displacement amount of an upper surface of a housing under a pressure application state, wherein FIG. 3A is a schematic vertical sectional view of a right half of the housing, and FIG. (C) is a perspective view of the substrate.

FIG. 4 is an overall longitudinal sectional view showing a conventional example.

[Explanation of symbols]

In the drawings, 11 is a housing, 12 is a housing body,
12a is a pressure receiving port, 12d is a trapezoid, 13 is a diaphragm, 14 is a substrate, 15 is a detection electrode, 16 is a reference electrode,
7 is a resin bead (spacer), 18 is a flexible adhesive, 1
Reference numeral 9 denotes a processing circuit LSI.

[Procedure amendment]

[Submission date] December 9, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3 shows the results of analyzing the amount of displacement of the upper surface of the housing under a pressure applied state, showing the sectional shape of the right half of the housing and the substrate
Figure shown with appearance

Claims (8)

[Claims] 1. A metal housing formed integrally with a housing body having a pressure receiving port into which a fluid to be subjected to pressure detection enters, and a diaphragm facing the pressure receiving port, and a metal housing opposite to a pressure receiving surface of the diaphragm. A detection electrode disposed opposite to the side surface with a predetermined gap therebetween, and a pressure acting on the diaphragm through the pressure receiving port, the amount of change in capacitance between the diaphragm and the detection electrode. A capacitance type pressure sensor characterized in that the detection is performed based on the following. 2. The apparatus according to claim 1, further comprising a substrate on which the detection electrode is formed, wherein the substrate is fixed to the housing via a spacer to set a gap dimension between the diaphragm and the detection electrode. The capacitance type pressure sensor according to claim 1, wherein 3. The capacitance type pressure sensor according to claim 2, wherein said substrate is fixedly adhered to said housing with a flexible adhesive. 4. The capacitance type pressure sensor according to claim 3, wherein said spacer is formed of a plurality of resin beads mixed with said flexible adhesive. 5. A substrate formed with the detection electrode, and a reference formed so as to face a surface of the substrate on the same side as the detection electrode with a predetermined gap from the housing main body. An electrode, and based on a deviation between the capacitance between the diaphragm and the detection electrode and the capacitance between the housing body and the reference electrode, the pressure acting on the diaphragm is detected. The capacitance type pressure sensor according to any one of claims 2 to 4, wherein 6. The area of the detection electrode and the reference electrode, the gap between the diaphragm and the detection electrode, and the gap between the housing body and the reference electrode are set to be equal to each other. The capacitance type pressure sensor as described in the above. 7. The capacitance-type pressure according to claim 5, wherein a fixed portion between the substrate and the housing is located at a position between the detection electrode and the reference electrode on the substrate. Sensor. 8. The surface of the diaphragm portion opposite to the pressure receiving surface and the surface of the housing main body portion facing the reference electrode are formed flush with each other. The capacitance-type pressure sensor according to 1.