JP2001343301A - Capacitance type pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitance type pressure sensor having good responsiveness and S/N ratio. SOLUTION: Pressure-leading holes 25 and 35 in respective fixed electrode members 2a and 3a are formed at positions facing the thin part 12 of a silicon member 1, a movable electrode member. The holes 25 and 35 are opened in spaces over and under the thin part 12 of the silicon member 1. Therefore, even when pressure difference becomes excessive and a movable electrode part 11 of the silicon member 1 is pressed onto a fixed electrode 21 (or 31) of the fixed electrode member 2a (or 3a) to block a through hole 24 (or 34), the space over (or under) the thin part 12 is not sealed and the responsiveness does not degraded. Thus, a groove provided in the fixed electrode part for securing the responsiveness in the prior art is not required, and with a fixed electrode with the same outer diameter, a large capactance value can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type for measuring a difference in pressure applied to both sides of a movable electrode by a change in capacitance between a fixed electrode and a movable electrode displaced in accordance with a pressure difference. It relates to a pressure sensor.

[0002]

2. Description of the Related Art There are two types of capacitance type pressure sensors: one having a single capacitor composed of a movable electrode and a fixed electrode;
There is a differential type having two capacitors in which two fixed electrodes are arranged approximately symmetrically on both sides of one movable electrode.
The present invention relates to a capacitance type pressure sensor having the latter structure (hereinafter, abbreviated as a pressure sensor). In the following description, when a pressure sensor is referred to, the capacitance type pressure sensor having this structure is referred to as a pressure sensor. Point.

FIG. 5 is a sectional view showing the structure of an example of a conventional pressure sensor. The silicon member 1 as a movable electrode member made of silicon, which is an excellent conductive material and an excellent elastic material, includes a movable electrode portion 11 and a thin portion 12.
Are formed by plasma etching from both sides. On both sides of the silicon member 1, two fixed electrode members 2 and 3 made of an insulating material having substantially the same thermal expansion coefficient as that of silicon, for example, Pyrex glass, are joined. And 3 are respectively formed with fixed electrodes 21 and 31 and through-hole / pressure-guiding holes 22 and 32.

The movable electrode portion 11 of the silicon member 1 is a portion for forming a capacitor with each of the fixed electrodes 21 and 31, and is plasma-etched from both sides by an amount corresponding to a gap for that purpose. The thin portion 12 is a portion that deforms under pressure and displaces the movable electrode portion 11, and is plasma-etched from both sides to a thickness that allows a necessary deformation according to a predetermined pressure difference.

The fixed electrode members 2 and 3 are also holding members for the silicon member 1. The silicon member 1 and the fixed electrode members 2 and 3 are hermetically joined at their outer peripheral portions by a method such as electrostatic joining. . The fixed electrodes 21 and 31 are arranged at positions opposing the movable electrode unit 11, and the through-hole and pressure guiding holes 22 and 32 introduce pressures P2 and P1, respectively, to the movable electrode unit 11 and the thin portion 12, And fixed electrodes 21 and 31
Are drawn out to the outer surfaces of the fixed electrode members 2 and 3, respectively, for connection to an external circuit. The fixed electrodes 21 and 31 and the lead-out portions are made of, for example, Cr / Au
It is formed as a metallized layer having a layered structure.

The insulating holding plate 4 is a member provided with a metallized layer for soldering on both sides of an insulating material plate, and is a capacitor forming portion (detection member) composed of the silicon member 1 and the fixed electrode members 2 and 3. ) Is a member for electrically insulating and holding the portion P1) and for introducing pressure P1 from one side, and has a pressure guiding hole 41 at the center. The insulating holding plate 4 and the fixed electrode member 3 are airtightly joined by fluxless solder joining, for example, solder joining with gold-tin eutectic solder. The metallized layer on the lower surface of the fixed electrode member 3 also serves as a metallized layer for this soldering.

The base 5 is a member for mounting the pressure sensor at a predetermined position by welding or the like, and is made of metal such as Kovar, and has a pressure guiding hole 51 at a central portion.
A pressure P1 is introduced through 51. Base 5 and insulating holding plate 4
In the same manner as in the case of the insulating holding plate 4 and the fixed electrode member 3, airtight bonding is performed by fluxless soldering, for example, soldering using gold-tin eutectic solder.

The above-described pressure sensor is housed in a housing (not shown), and a pressure transmission medium such as silicone oil is sealed in the housing, and the pressures P1 and P2 are applied to the silicon member 1 via the pressure transmission medium. Is applied to both pressure receiving surfaces.

[0009]

In the above pressure sensor, when either P1 or P2 becomes excessive, the movable electrode section 11 is pressed against the fixed electrode 21 or the fixed electrode 31, and The through-hole and pressure-guiding hole 22 or 32 is closed, and the space above or below the thin portion 12 becomes a sealed space. Thereafter, even if the overpressure disappears, the pressure transmission medium is hardly supplied to this closed space, and the return of the movable electrode unit 11 becomes extremely slow. As a matter of course, even when the distance between the fixed electrode 21 or 31 and the movable electrode section 11 becomes very small, the response of the pressure transmission medium becomes slow because the flow path of the pressure transmission medium becomes narrow.

If the distance between the electrodes is reduced to increase the capacitance value in order to improve the S / N ratio, this problem becomes more remarkable. For reference, the conventional example of the distance between the movable electrode portion 11 and the fixed electrodes 21 and 31 in a state where there is no differential pressure is 5 μm. In order to solve such problems,
In the prior art, as shown in FIG. 6, the portion of the fixed electrode member 2 where the fixed electrode 21 is formed, that is, the movable electrode portion 11
A groove 23 extending from the through-hole and the pressure-guiding hole 22 to the outer periphery of the fixed electrode 21 is formed in a region slightly larger than the portion where the contact is made. The groove 23 secures the flow path of the pressure transmitting medium, and the pressure transmitting medium can be easily supplied to the space above the thin portion 12, and a predetermined responsiveness is obtained. The same is true for the fixed electrode member 3.

However, by forming the groove 23, the effective area of the fixed electrode 21 (and 31) forming the capacitor decreases, and the capacitance value of the capacitor decreases.
As a result, the S / N ratio deteriorates. An object of the present invention is to solve the above-described problems and to improve the responsiveness and S / N.
It is to provide a pressure sensor having an excellent ratio.

[0012]

According to the present invention, a thin portion and a movable electrode portion are provided as a pressure receiving portion. The thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is thin. A conductive movable electrode member that is surrounded by the portion and is displaced in accordance with the pressure difference due to the deformation of the thin portion, a fixed electrode provided at a position facing the movable electrode portion, and a fixed electrode provided for connecting the fixed electrode to an external circuit. A pressure sensor having a through hole and a pressure guiding hole for introducing pressure to a pressure receiving portion of the movable electrode member, and a pair of insulating fixed electrode members joined to both surfaces of the movable electrode member; The pressure guiding hole is a through hole provided at a position facing the thin portion (the invention of claim 1).

Since the pressure guiding hole is provided at a position opposed to the thin portion, even if the movable electrode contacts the fixed electrode due to excessive pressure, only the through hole at the center of the fixed electrode forms a closed space. Since the pressure transmitting medium is supplied from the outer peripheral portion of the movable electrode portion having a long perimeter to the through hole, the responsiveness is improved, and a groove formed in the fixed electrode member is not required for improving the responsiveness. .

In the first aspect of the present invention, the pressure guiding hole provided at a position facing the thin portion also serves as a through hole for connecting the fixed electrode to an external circuit (the second aspect of the invention). Since the pressure guiding hole also serves as a through hole, even when the movable electrode portion comes into contact with the fixed electrode due to excessive pressure, a closed space is not formed, and responsiveness is further improved. Further, the number of through-holes to be machined in the fixed electrode member is reduced by the amount of the shared use.

The pressure receiving portion has a thin portion and a movable electrode portion. The thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is surrounded by the thin portion and deforms the thin portion. And a fixed electrode provided at a position facing the movable electrode portion, a through hole for connecting the fixed electrode to an external circuit, and a pressure receiving portion of the movable electrode member. In a pressure sensor having a pressure guiding hole for introducing pressure to the movable electrode member and a pair of insulating fixed electrode members joined to both surfaces of the movable electrode member, the pressure guiding hole has a movable electrode member and A through hole located at a joint of the fixed electrode member, and a member for connecting the movable electrode member and the fixed electrode member to one of the joining surfaces, for communicating the through hole with a space above or below the thin portion. The pressure guiding groove is formed That (the invention of claim 3).

Since the pressure transmitting medium is supplied to the space above and below the thin portion by the through hole and the pressure guiding groove, the responsiveness is improved as in the first aspect of the present invention, and the responsiveness is fixed to improve the responsiveness. There is no need for a groove formed in the electrode member. Furthermore,
A thin portion and a movable electrode portion as a pressure receiving portion are provided at a plurality of locations, and the thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is surrounded by the thin portion and deformed by the thin portion. A conductive movable electrode member that is displaced in accordance with the pressure difference, and respective through holes for connecting the fixed electrodes and the fixed electrodes provided at positions facing the plurality of movable electrode portions to an external circuit, and A pressure having a plurality of detectors having a pair of insulating fixed electrode members having a pressure guiding hole for introducing pressure to each pressure receiving portion of the movable electrode member and being joined to both surfaces of the movable electrode member. In the sensor, the pressure guiding hole is located at a joint portion between the movable electrode member and the fixed electrode member, and is a common through hole for a plurality of detection portions, and may be any one of the joint surfaces of the movable electrode member and the fixed electrode member. In the member, A plurality of electrically grooves for communicating and all holes and a plurality of detector above or below the space of the thin portion of the movable electrode member is formed (invention of claim 4).

Since the pressure guiding groove communicates from one through hole to the space above or below the thin portion of the movable electrode members of all the detection units, all the detection units are connected in the same manner as in the third aspect of the present invention. ,
The responsiveness is improved, and a groove for improving the responsiveness formed in the fixed electrode member is not required. Furthermore, even if there are a plurality of detection units, the through hole serving as the pressure guiding hole can be a single through hole common to all the detection units.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The feature of the present invention is that the measurement pressure is directly introduced into the space above and below the thin portion, so that even if the movable electrode portion is pressed against the fixed electrode, the space above or below the thin portion is obtained. Is not to be an enclosed space, and the necessary responsiveness is secured. An embodiment of a pressure sensor according to the present invention will be described using an example.

The parts having the same functions as those of the prior art are denoted by the same reference numerals. [First Embodiment] FIG. 1 is a sectional view showing the structure of a first embodiment of the pressure sensor according to the present invention. The difference from the conventional example shown in FIG. 5 is that the pressure guiding holes for introducing the measurement pressures P1 and P2 are provided.
35 and 25 are formed at positions facing the thin portion 12 of the silicon member 1 as a movable electrode member.

The details will be described below. A movable electrode portion 11 and a thin portion 12 are formed on a silicon member 1 as a movable electrode member made of silicon, which is an excellent conductive material and an excellent elastic material, by plasma etching from both sides. On both sides of the silicon member 1, an insulating material having a thermal expansion coefficient substantially equal to that of silicon,
For example, two fixed electrode members 2a and 3a made of Pyrex (registered trademark) glass are joined, and the fixed electrode members 2a and 3a are respectively connected to the fixed electrodes 21 and 31, the through holes 24 and 34, and the pressure guiding holes. 25 and 35 are formed.

The movable electrode portion 11 of the silicon member 1 is a portion for forming a capacitor with the fixed electrodes 21 and 31, respectively, and is plasma-etched from both sides by an amount corresponding to a gap for that purpose. The thin portion 12 is a portion that deforms under pressure and displaces the movable electrode portion 11, and is plasma-etched from both sides to a thickness that allows a necessary deformation according to a predetermined pressure difference.

The fixed electrode members 2a and 3a are connected to the silicon member 1
The silicon member 1 and the fixed electrode member 2a
And 3a are hermetically joined at their outer peripheral portions by a method such as electrostatic joining. The fixed electrodes 21 and 31 are arranged at positions facing the movable electrode unit 11. The through holes 24 and 34 formed in the center part are fixed electrodes.
In order to connect 21 and 31 to an external circuit, fixed electrodes 21 and
31 is pulled out to the outer surfaces of the fixed electrode members 2a and 3a, respectively.
The pressure guiding holes 25 and 35 formed at positions facing the thin portion 12 of the silicon member 1 introduce pressures P2 and P1 to the movable electrode portion 11 and the thin portion 12, respectively. The fixed electrodes 21 and 31 and the lead portions thereof are formed as a metallized layer having a two-layered structure of, for example, Cr / Au by a method such as a mask sputtering method from both sides.

The insulating holding plate 4a is a member having a metallized layer for soldering on both sides of an insulating material plate, and includes a capacitor forming portion (detection portion) composed of the silicon member 1 and the fixed electrode members 2a and 3a. ) Is a member for electrically insulating and holding the portion) and introducing pressure P1 from one side, and has a pressure guiding hole 41 at a position corresponding to the pressure guiding hole 35 of the fixed electrode member 3a. . The insulating holding plate 4a and the fixed electrode member 3a are airtightly joined by fluxless soldering, for example, by soldering using gold-tin eutectic solder. The metallized layer on the lower surface of the fixed electrode member 3a also serves as a metallized layer for soldering.

The base 5a is a member for mounting the pressure sensor at a predetermined position by welding or the like. The base 5a is made of a metal such as Kovar, and is provided at a position corresponding to the pressure guide hole 41 of the insulating holding plate 4a. It has a hole 51, and the pressure P 1 is introduced through the dynamic pressure hole 51. The base 5a and the insulating holding plate 4a are hermetically bonded by fluxless solder bonding, for example, soldering with gold-tin eutectic solder, similarly to the case of the insulating holding plate 4a and the fixed electrode member 3a. .

The above-described pressure sensor is housed in a housing (not shown), and a pressure transmission medium such as silicone oil is sealed in the housing. The pressures P1 and P2 are applied to the silicon member 1 via the pressure transmission medium. Is applied to both pressure receiving surfaces. In the assembly of such a pressure sensor, electrostatic bonding can directly bond the materials to be bonded,
It has features that the accuracy of the distance between the electrodes of the capacitor can be easily secured, the airtightness can be secured, and no large-scale equipment is required.

According to this embodiment, the pressure guiding holes 25 and 35 are
Formed at a position facing the thin portion 12 of the silicon member 1;
Since it is directly connected to the space above and below the thin part 12, P1 or P2
Does not become excessively large and the responsiveness when the excessive pressure disappears does not become slow even if the movable electrode section 11 is pressed against the fixed electrode 21 or 31. The reason for this is that the measurement pressure P2 or P1 is directly introduced into the space above and below the thin portion 12 having a large pressure receiving area. Alternatively, since it is supplied to the, the required responsiveness can be secured without forming a groove for securing a predetermined responsiveness in the fixed electrode portion.

In the above description, Pyrex glass is used as an example of the material of the fixed electrode members 2a and 3a. However, a material having a thermal expansion coefficient substantially equal to that of the silicon member 1 and capable of being electrostatically bonded to the silicon member 1 is used. Is limited to glass such as Pyrex glass. On the other hand, materials having the same thermal expansion coefficient and higher strength and rigidity than such glass include, for example, ceramics such as silicon nitride and cordierite-mullite ceramics. However, it is difficult for these ceramics to be directly electrostatically bonded to silicon. In order to enable electrostatic bonding, it is necessary to form a sputtered layer of glass such as Pyrex glass on the surface of the ceramic. The reason for the need for high-strength materials is to increase the breaking strength of the detector to improve reliability. If the rigidity is increased, the size of the detector can be reduced and the cost can be reduced.

Therefore, in order to increase the reliability and reduce the size and accuracy of the pressure sensor of the first embodiment, the material of the fixed electrode members 2a and 3a was formed from Pyrex glass and a Pyrex glass layer was formed on the surface. It is effective to substitute ceramics. The effect of this material change is similarly effective in the following examples. [Second Embodiment] FIG. 2 is a sectional view showing the structure of the second embodiment.

The difference between this embodiment and the first embodiment is that
The pressure guiding holes 25 and 35 in the first embodiment are replaced with through holes / pressure guiding holes 22a and 32a, and the fixed electrodes 21 and 31 are replaced.
Is that the through holes 24 and 34 at the center of are removed. By eliminating the through-hole 34, even if the movable electrode portion 11 is pressed against the fixed electrode 31, a closed space corresponding to the through-hole is not formed, so that better responsiveness can be obtained. Further, the capacitance of the capacitor is increased by an area corresponding to the through holes 24 and 34, and the S / N
The ratio improves.

[Third Embodiment] FIG. 3 is a sectional view showing the structure of the third embodiment. In this embodiment, the pressure guiding holes 25 and 35 in the first embodiment are respectively formed at the positions where the silicon member 1a and the fixed electrode members 2c and 3c are joined to each other. That is, they are replaced by pressure guiding grooves 26 and 36 provided on the joint surface side of 2c and 3c. The pressure guiding grooves 26 and 36 are
25 and 35 are communicated with the upper and lower spaces of the thin portion 12.

The pressure guiding grooves 26 and 36 have a width of about 0.5 mm.
And has a depth of about 0.5 mm and is formed by sandblasting. If the width of the pressure guiding grooves 26 and 36 is 0.5 mm, set the depth to 0.
The required responsiveness can be ensured even if the depth is reduced to 1 mm. Further, when changing the width of the pressure guiding grooves 26 and 36, it is necessary to adjust the depth so as to obtain the same cross-sectional area. When the lengths of the pressure guiding grooves 26 and 36 are increased, the cross-sectional area must be increased accordingly. For reference, the thickness of the fixed electrode members 2c and 3c in the embodiment is 2 mm.

Also in this embodiment, the pressure guiding holes 25a and 35
a and the pressure guiding grooves 26 and 36 reduce the pressure P2 and P1
Since a passage for direct introduction is secured in the upper and lower spaces of 12, even in the same manner as in the first embodiment, a groove for ensuring a predetermined responsiveness is not formed in the fixed electrode portion. Necessary responsiveness can be secured. In the above embodiment, the pressure guiding grooves 26 and 36 are fixed electrode members 2c and 3c, respectively.
However, the pressure-guiding groove may be formed on the silicon member 1a side. In this case, it can be formed at the same time as the plasma etching for forming the thin portion 12, and there is no need to add a special process. However,
Since there is a limit to the depth of the groove that can be formed by plasma etching, it is necessary to increase the width of the groove according to the limit. For example, when the thickness of the silicon wafer, which is the material of the silicon member 1a, is 200 μm, the depth etched from one side is at most 90 μm. Therefore, it is desirable to set the width of the groove to about 1 mm.

[Fourth Embodiment] FIG. 4 is a sectional view showing the structure of a fourth embodiment. In this embodiment, a plurality of detecting portions are formed in one pressure sensor, and the pressure introducing portion has the same configuration as that of the third embodiment. The plurality of detection units correspond to, for example, different ranges, and can ensure high measurement accuracy over a wide pressure range.

FIG. 4 shows a detection unit for measuring a higher differential pressure added to the right side of the pressure sensor shown in FIG. 3, and only a part of the added detection unit is shown. The silicon member 1b has a movable electrode portion supported by the thin thin portion 12.
11 and a movable electrode portion 11a supported by the thick thin portion 12a. The fixed electrode members 2d and 3d have fixed electrodes 21 and 31 facing the movable electrode portion 11, fixed electrodes 21a and 31a facing the movable electrode 11a, and through holes 24 and 31 for the fixed electrodes 21 and 31, respectively. 34 and fixed electrode 21a
And each through hole not shown for 31a, and
Pressure guiding holes 25a and 35a and pressure guiding grooves 26 and 36 are formed. The pressure guiding holes 25a and 35a are formed at the joint positions between the silicon member 1b and the fixed electrode members 2d and 3d, and at intermediate positions between the two detecting portions. The pressure guiding grooves 26a and 36a are provided on the joint surface side of the fixed electrode members 2d and 3d, respectively.
The pressure guiding holes 25a and 35a and the thin portion of the silicon member 1b respectively
The upper and lower spaces of 12 and 12a are communicated. One pressure guiding hole 25a (or 35a) and two pressure guiding grooves 26 (or 36)
The pressure P2 (or P1) is introduced into the two detection units.

In the above embodiment, the shape of the insulating holding plate and the base and the positions of the pressure guiding holes are changed in accordance with the positions of the pressure guiding holes of the lower fixed electrode member. It is formed large enough to hold the formation.
Regarding the size of the insulating holding plate, in the embodiments other than the second embodiment, it is necessary that the insulating holding plate extends to a position that closes the through hole of the fixed electrode member on the insulating holding plate side. If this condition is satisfied and the capacitor forming portion can be securely held, the size of the insulating holding plate is not necessarily required to be the same as the size of the fixed electrode member as shown in FIG. The size of the base needs to be made slightly larger than the size of the insulating holding plate in order to weld the base to the housing.

[0036]

According to the present invention, the pressure receiving portion has a thin portion and a movable electrode portion, and the thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is surrounded by the thin portion. A conductive movable electrode member which is displaced in accordance with the pressure difference due to deformation of the thin portion, a fixed electrode provided at a position facing the movable electrode portion, a through hole for connecting the fixed electrode to an external circuit, and A pressure sensor having a pressure guiding hole for introducing pressure to a pressure receiving portion of the movable electrode member, and a pair of insulating fixed electrode members joined to both surfaces of the movable electrode member; However, since it is a through hole provided at a position facing the thin portion, even if the movable electrode portion contacts the fixed electrode due to excessive pressure, only the central portion of the fixed electrode becomes a closed space. , Mobile phone with long perimeter The pressure transmitting medium from the outer circumference to the through-hole parts are provided, the better the response, does not require a formed in the fixed electrode member in order to improve the responsiveness groove. Therefore, it is possible to provide a pressure sensor excellent in responsiveness and S / N ratio (the invention of claim 1).

According to the first aspect of the present invention, since the pressure guiding hole provided at a position facing the thin portion also serves as a through hole for connecting the fixed electrode to an external circuit, the fixed electrode can be moved by excessive pressure. Even when the electrode portions come into contact with each other, a closed space is not formed, the responsiveness is further improved, and the number of through-holes formed in the fixed electrode member is reduced by the amount of the dual use. 2).

The pressure receiving portion has a thin portion and a movable electrode portion, and the thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is surrounded by the thin portion and deforms the thin portion. And a fixed electrode provided at a position facing the movable electrode portion, a through hole for connecting the fixed electrode to an external circuit, and a pressure receiving portion of the movable electrode member. In a pressure sensor having a pressure guiding hole for introducing pressure to the movable electrode member and a pair of insulating fixed electrode members joined to both surfaces of the movable electrode member, the pressure guiding hole has a movable electrode member and A through hole located at a joint of the fixed electrode member, and a member for connecting the movable electrode member and the fixed electrode member to one of the joining surfaces, for communicating the through hole with a space above or below the thin portion. The pressure guiding groove is formed Runode, pressure transmission medium and below the space of the thin portion through the through hole and conductive grooves are supplied directly,
As in the first aspect of the invention, the response is improved, and a groove for improving the response formed in the fixed electrode member is not required. Therefore, according to the present invention, responsiveness and S /
A pressure sensor excellent in N ratio can be provided (the invention of claim 3).

Further, a thin portion as a pressure receiving portion and a movable electrode portion are provided at a plurality of locations, the thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is surrounded by the thin portion and A conductive movable electrode member that is displaced in accordance with the pressure difference due to the deformation of the thin portion, and a fixed electrode provided at a position opposed to the plurality of movable electrode portions and a fixed electrode for connecting the fixed electrode to an external circuit. A plurality of through-holes and a pair of insulating fixed electrode members having a pressure guiding hole for introducing pressure to each pressure receiving portion of the movable electrode member, and a pair of insulating fixed electrode members joined to both surfaces of the movable electrode member; In the pressure sensor having a detecting portion, the pressure guiding hole is located at a joint between the movable electrode member and the fixed electrode member, and is a through hole common to the plurality of detecting portions. No face In such a member, since a pressure guiding groove for communicating the through-hole and all of the space above or below the thin portion of the movable electrode member of the plurality of detection units is formed, all the detection units are As in the third aspect of the invention, the responsiveness is improved, and a groove for improving the responsiveness formed in the fixed electrode member is not required. Furthermore, even if there are a plurality of detection units,
The through hole serving as the pressure guiding hole can be one through hole common to all the detection units. Therefore, according to the present invention, it is possible to provide a pressure sensor having a plurality of detectors excellent in responsiveness and S / N ratio with a small number of man-hours (the invention of claim 4).

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of a first embodiment of a pressure sensor according to the present invention.

FIG. 2 is a sectional view showing a structure of a second embodiment.

FIG. 3 is a sectional view showing the structure of a third embodiment.

FIG. 4 is a sectional view showing the structure of a fourth embodiment.

FIG. 5 is a sectional view showing the structure of a conventional example.

FIG. 6 is a plan view of a fixed electrode member for explaining a response improvement measure according to the related art.

[Explanation of symbols]

 1, 1a, 1b Silicon member 11, 11a Movable electrode portion 12, 12a Thin portion 2, 2a, 2b, 2c, 2d Fixed electrode member 21, 21a Fixed electrode 22, 22a Through hole and pressure guiding hole 23 Groove 24 Through hole 25 25a pressure hole 26 pressure groove 3, 3a, 3b, 3c, 3d fixed electrode member 31, 31a fixed electrode 32, 32a through hole and pressure hole 34 through hole 35, 35a pressure hole 36 pressure groove 4, 4a, 4b, 4c Insulation holding plate 41 Pressure guiding hole 5, 5a, 5b, 5c Base 51 Pressure guiding hole

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masato Takahashi 1-1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Shinichi Soma 1st Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture No. 1 Inside Fuji Electric Co., Ltd. (72) Inventor Kimihiro Nakamura 1-1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture F-term inside Fuji Electric Co., Ltd. 2F055 AA40 BB05 CC02 DD05 EE25 FF11 FF17 FF43 GG25

Claims (4)

[Claims] The pressure receiving portion has a thin portion and a movable electrode portion. The thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is surrounded by the thin portion and deforms the thin portion. And a fixed electrode provided at a position facing the movable electrode portion, a through hole for connecting the fixed electrode to an external circuit, and a pressure receiving portion of the movable electrode member. In a capacitive pressure sensor having a pressure guiding hole for introducing pressure to the movable electrode member and a pair of insulating fixed electrode members joined to both surfaces of the movable electrode member, A capacitance type pressure sensor comprising a through hole provided at a position facing the thin portion. 2. The capacitance according to claim 1, wherein the pressure guiding hole provided at a position facing the thin portion also serves as a through hole for connecting the fixed electrode to an external circuit. Type pressure sensor. 3. The pressure receiving portion has a thin portion and a movable electrode portion. The thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is surrounded by the thin portion and deforms the thin portion. And a fixed electrode provided at a position facing the movable electrode portion, a through hole for connecting the fixed electrode to an external circuit, and a pressure receiving portion of the movable electrode member. In a capacitive pressure sensor having a pressure guiding hole for introducing pressure to the movable electrode member and a pair of insulating fixed electrode members joined to both surfaces of the movable electrode member, A through hole located at a joint between the movable electrode member and the fixed electrode member; and a member above the joint surface between the movable electrode member and the fixed electrode member, the through hole and a space above or below the thin portion. A pressure guide groove for communication is formed Capacitive pressure sensor, characterized by being. 4. A thin portion as a pressure receiving portion and a movable electrode portion at a plurality of locations, the thin portion is deformed by a difference in pressure applied to both surfaces of the pressure receiving portion, and the movable electrode portion is surrounded by the thin portion and A conductive movable electrode member that is displaced in accordance with the pressure difference due to the deformation of the thin portion, and a fixed electrode provided at a position opposed to the plurality of movable electrode portions and a fixed electrode for connecting the fixed electrode to an external circuit. A plurality of through-holes and a pair of insulating fixed electrode members having a pressure guiding hole for introducing pressure to each pressure receiving portion of the movable electrode member, and a pair of insulating fixed electrode members joined to both surfaces of the movable electrode member; In the capacitive pressure sensor having a detection unit, the pressure guiding hole is located at a joint between the movable electrode member and the fixed electrode member, and is a through hole common to a plurality of detection units. Electrode member joining surface A plurality of pressure guiding grooves for communicating the through hole with all of the space above or below the thin portion of the movable electrode member of the plurality of detection units are formed in any one of the members. Capacitive pressure sensor.