JP6534548B2 - Sensor module - Google Patents

Description

  The present invention relates to a sensor module.

Among capacitance type pressure sensors, there are those provided with a sensor module in which electrodes are provided on a pedestal portion and a diaphragm portion, respectively, and a capacitor of capacitance is configured by these electrodes. In this pressure sensor, when the diaphragm portion is displaced by the pressure of the fluid to be measured, the capacitance between the electrodes changes, so that the pressure value converted accordingly is detected.
As a conventional example, a substrate and an elastic diaphragm opposed to the substrate at a predetermined interval are provided, and a circular central electrode and an annular reference electrode are formed on the substrate so as to be separated from each other. There is a capacitance type pressure sensor in which a common electrode having a diameter larger than that of a reference electrode is formed in a circular shape on the opposite surface (Patent Document 1).

As another conventional example, there is a capacitive pressure sensor in which a diaphragm and a substrate are disposed apart from each other, and a measurement electrode and a reference electrode are formed on the surfaces facing each other (Patent Document 2). .
As another conventional example, a capacitive pressure sensor in which a sensor diaphragm and a sensor pedestal are disposed apart from each other and a plurality of fixed electrodes and a plurality of movable electrodes are formed separately on their mutually opposing surfaces is (Patent Document 3).

An example that is similar to Patent Document 1 will be described based on FIGS. 10 to 12.
A cross section of the sensor module 100 is shown in FIG.
In FIG. 10, the sensor module 100 has a structure in which a pedestal portion 101 and a diaphragm portion 102 are bonded to each other via a cylindrical bonding glass 103. The pedestal side electrode portion 104 is provided on the pedestal portion 101. The pedestal-side electrode portion 104 includes a central electrode 104M provided at the central portion of the pedestal portion 101, a reference electrode 104R provided on the outer peripheral side of the central electrode 104M, and a shield electrode 104S provided on the outer periphery of the reference electrode 104R. Have.
The diaphragm portion 102 is provided with a diaphragm side electrode portion 105. The diaphragm side electrode unit 105 includes a common electrode 105C facing the pedestal side electrode unit 104, and a shield electrode 105S provided on the opposite side to the common electrode 105C via the shield coat 106.

The plane of pedestal 101 is shown in FIG. As shown in FIG. 11, the central electrode 104M is circular, and the reference electrode 104R and the shield electrode 104S are annular with the center of the central electrode 104M being concentric.
The plane of the diaphragm portion 102 is shown in FIG. As shown in FIG. 12, the common electrode 105C is circular, and its outer peripheral edge is larger than the outer peripheral edge of the reference electrode 104R in plan view (see FIG. 10). Although both the central electrode 104M shown in FIG. 11 and the common electrode 105C shown in FIG. 12 are hatched, they do not show a cross section, and the configuration of these electrodes is easy to understand. belongs to.
In the sensor module 100 having such a configuration, the diaphragm portion 102 which receives pressure is bent, and a gap between the central electrode 104M and the reference electrode 104R provided on the pedestal portion 101 and the common electrode 105C provided on the diaphragm portion 102 The change is detected as a change in capacitance.

Assuming that the capacitance between the central electrode 104M and the common electrode 105C is Cm and the capacitance between the reference electrode 104R and the common electrode 105C is Cr, the pressure conversion value K of the entire sensor module is It is calculated based on the arithmetic expression.
K1 = Cm-Cr (1)
K2 = Cm / Cr (2)
K3 = (Cm-Cr) / (Cm + Cr) (3)

Patent No. 2815279 Japanese Patent Application Laid-Open No. 8-285714 JP, 2006-10539, A

  In the prior art of Patent Document 1, the center electrode and the reference electrode must have a certain size because of the restriction of the capacitance detection capability. In order to miniaturize the sensor, these electrodes are in close proximity. Moreover, since the common electrode is formed on the entire surface of the diaphragm, in Patent Document 1, when detecting the capacitance, the capacitance generated between the center electrode and the common electrode, and the reference electrode There is a point of interference with the capacitance generated between the common electrode and the common electrode.

That is, in the example shown in FIG. 10 to FIG. 12, the common electrode 105C is formed on a solid surface on the same surface, and is stationary between the central electrode 104M and the reference electrode 104R which are close to each other. It forms the capacitance. Therefore, when the capacitance is detected, an interference point A is generated between the center electrode 104M and the reference electrode 104R.
In this interference point A, the range ratio of the common electrode 105C constituting the electrode is also changed due to the change of the surrounding environment (disturbance of temperature, humidity and noise, etc.) and the end effect of the capacitor. , Leads to detection error.

Furthermore, the apparent area of the electrodes facing each other changes due to slight displacement between the electrode positions of the diaphragm portion 102 and the pedestal portion 101, the inclination of the bonding glass 103, and the difference in the bending of the diaphragm portion 102. This will cause variations in the characteristics of the sensor module.
Then, in order to balance the capacitance with the central electrode 104M, it is necessary to set the area of the reference electrode 104R large, so that the deflection of the diaphragm portion 102 due to pressurization is directly affected as a change in the capacitance. Since the pattern extends up to the point, the amount of change in the capacitance formed by the reference electrode 104R is large, and the output due to the change in capacitance of the center electrode 104M thus obtained is as shown in equations (1) to (3). Since it acts in the decreasing direction, the span of the output decreases.

  In the prior art examples of Patent Documents 2 and 3, the electrodes provided on the diaphragm and the electrodes provided on the substrate are each constituted by a plurality, but the reason for providing a plurality of these electrodes, and There is no description about the shape of these electrodes. Patent Documents 2 and 3 can not find a description suggesting the problem of Patent Document 1 that interference places are generated due to at least the relationship between the electrode provided on the diaphragm and the electrode provided on the substrate.

  An object of the present invention is to provide a sensor module capable of suppressing detection errors.

The sensor module according to the present invention includes a pedestal, a diaphragm disposed on the pedestal, a pedestal-side electrode disposed on the pedestal, and the diaphragm disposed to face the pedestal-side electrode. and the diaphragm-side electrode portion, wherein the base-side electrode portion includes a central electrode disposed in a central portion, and a reference electrode of annular disposed away from the outer peripheral edge of the central electrode, before Symbol The diaphragm-side electrode portion has a common electrode, and the common electrode is a first electrode facing the central electrode, and an annular second member disposed apart from the outer peripheral edge of the first electrode and facing the reference electrode. possess the electrode, wherein the linear conductive portion between the first electrode and the second electrode is connected to the conductive portion, positioned such two positions across the first electrode becomes linear Part of the outer peripheral edge of the second electrode The electrode lead-out portion is connected to the electrode lead-out portion is characterized by being formed along the longitudinal direction of the conductive portion.

In the present invention, the central electrode and the first electrode face each other, the reference electrode and the second electrode face each other, and there is a gap between the first electrode and the second electrode where no electrode is provided. The interference between the electrostatic capacitance generated between the electrode and the first electrode and the electrostatic capacitance generated between the reference electrode and the second electrode can be reduced, so that the detection error of the sensor module can be suppressed. .
Moreover, by electrically connecting the first electrode and the second electrode, a sufficient effect as a common electrode can be obtained. Since the conductive part is linear, even if the capacitance generated between the center electrode and the first electrode interferes with the capacitance generated between the reference electrode and the second electrode, the amount is extremely high. Few.
Here, if the number of conductive parts is one, the first electrode and the second electrode can not be electrically connected if they are cut, but if there are two, one is temporarily cut. However, since the first electrode and the second electrode are electrically connected by the remaining conductive portion, a sufficient effect as a common electrode can be obtained.

In the present invention, the dimension between the first electrode and the second electrode is the surface of the pedestal portion on which the pedestal side electrode portion is formed and the surface on which the diaphragm side electrode of the diaphragm portion is to be formed. 10 times or more of the dimension between them.
If the dimension between the first electrode and the second electrode is less than 10 times the dimension between the surface of the pedestal portion and the surface of the diaphragm portion, the effect of separating the first electrode and the second electrode is sufficient. Instead, the degree of interference between the capacitances generated between the center electrode and the first electrode and between the reference electrode and the second electrode increases, which causes a disadvantage in detection.

In the present invention, preferably, the second electrode has a radial dimension larger than that of the reference electrode.
In this configuration, even if the second electrode is offset from the position where it correctly faces the reference electrode and the diaphragm portion is attached, the capacitance generated between the center electrode and the first electrode, the reference electrode, and the first electrode There is less interference with the capacitance generated between the two electrodes.

In the present invention, it is preferable that the sheet Rudo electrodes are provided on one and the pedestal side electrode portion and the diaphragm-side electrode portion.
In this configuration, the shielding effect can reduce electrostatic capacitance interference. In addition, it is possible to suppress a detection error due to interference between the center electrode and the reference electrode due to high humidity by the shield effect by the shield electrode on the inner peripheral side.

In the present invention, the central electrode, the reference electrode, and the shield electrode are formed on the pedestal portion, and the common electrode is formed on an insulating member provided on a surface of the diaphragm portion facing the pedestal portion. Preferably, a shield electrode other than the shield electrode is provided on the surface of the insulating member opposite to the surface on which the common electrode is formed.
In this configuration, the shielding effect can reduce electrostatic capacitance interference, and even if the liquid contact is filled with a conductive substance such as water, the influence can be reduced and detection error is suppressed. I can hope. Also, as described above, when shield electrodes are provided on the inner and outer circumferential sides sandwiching the reference electrode, the interaction between these electrodes causes a malfunction and detection error due to radiation and conductive electromagnetic noise. I can expect to suppress it.

Sectional drawing which shows the sensor module of 1st Embodiment of this invention. The top view which shows the plane which opposes the diaphragm part of a base part. FIG. 5 is a plan view showing the positional relationship between a reference electrode and a hole. The top view which shows the plane which opposes the base part of a diaphragm part. The top view which expanded a part of diaphragm part. The sensor module of 2nd Embodiment of this invention is a figure corresponded in FIG. The top view which shows the plane which opposes the diaphragm part of a base part. FIG. 5 is a plan view showing the positional relationship between a reference electrode and a hole. The figure which shows the sensor module of 3rd Embodiment of this invention, and is a figure corresponded in FIG. Sectional drawing of the sensor module of the example approximated to patent document 1. FIG. The top view which shows the base part of the example approximated to patent document 1. FIG. The top view which shows the diaphragm part of the example approximated to patent document 1. FIG.

First Embodiment
A first embodiment of the present invention will be described based on FIGS. 1 to 5.
The overall configuration of the sensor module 10 is shown in FIG.
In FIG. 1, a sensor module 10 is a pressure conversion element disposed inside a pressure sensor (not shown), and an electrical output signal of the pressure of the fluid to be measured in order to detect the pressure of the fluid to be measured Convert to
The sensor module 10 includes a pedestal 11, a diaphragm 12 disposed to face the pedestal 11, and a cylindrical bonding glass 13 disposed between the pedestal 11 and the diaphragm 12 There is. The thickness dimension of the bonding glass 13 is L.

The pedestal portion 11 is made of a ceramic thick disc and has an outer diameter of, for example, 30 mm. A pedestal side electrode portion 14 is provided on the surface of the pedestal portion 11 facing the diaphragm portion side. The pedestal-side electrode portion 14 is formed by printing and applying an Ag—Pd paste on the flat surface of the pedestal portion 11 and baking it.
The pedestal-side electrode portion 14 has a central electrode 14M provided at the central portion, and an annular reference electrode 14R provided on the outer peripheral side of the central electrode 14M and on the inner peripheral side of the bonding glass 13. The central electrode 14M is a moving electrode, and the reference electrode 14R is a fixed electrode.
The central electrode 14M and the reference electrode 14R are covered with a glass coat 14G, and the outer peripheral edge of the glass coat 14G is joined to the bonding glass 13.

The diaphragm portion 12 is in the shape of a thin disk made of ceramic, and the outer diameter dimension thereof is equal to the outer diameter dimension of the pedestal portion 11. A common electrode 15C is provided on the surface of the diaphragm 12 facing the pedestal side. The common electrode 15 </ b> C is formed by printing and applying a metal organic paste (for example, Au resinate) on the flat surface of the diaphragm portion 12 and baking it.
The common electrode 15C has a first electrode 15C1 facing the central electrode 14M, and an annular second electrode 15C2 which is disposed apart from the outer peripheral edge of the first electrode 15C1 and faces the reference electrode 14R.
In the present embodiment, when the diaphragm portion 12 is bent by the pressure of the fluid to be measured, the electrostatic capacity between the center electrode 14M and the first electrode 15C1 and the static capacity between the reference electrode 14R and the second electrode 15C2 are obtained. The pressure of the fluid to be measured is detected from the change in capacitance.

  In FIG. 1, hatching indicating a cross section of the pedestal 11 and the diaphragm 12 is omitted. Furthermore, although the pedestal side electrode portion 14 and the common electrode 15C are illustrated thick, this is for the purpose of making the installation positions of the pedestal side electrode portion 14 and the common electrode 15C easy to understand, and the actual thickness is It is extremely small with respect to the outside diameter size of pedestal 11. For example, the thickness of the pedestal-side electrode portion 14 after firing is, for example, about 5 μm, and the thickness of the common electrode 15C after firing is about 0.5 μm. In addition, the dimension L between the surface 11B on which the pedestal side electrode portion 14 of the pedestal portion 11 is formed and the surface 12B on which the common electrode 15C of the diaphragm portion 12 is formed is about 10 μm.

In FIG. 2, a plane facing the diaphragm portion 12 of the pedestal portion 11 is shown.
In FIG. 2, the central electrode 14 </ b> M is a circle whose center of circle coincides with the central portion of the pedestal 11. The diameter MD of the central electrode 14M is, for example, 7 mm.
The reference electrode 14R is disposed concentrically with the central electrode 14M. The reference electrode 14R has an inner peripheral diameter RD1 of, for example, 18 mm, and an outer peripheral diameter RD2 of, for example, 19 mm. No electrode is formed in the region between the inner periphery of the reference electrode 14R and the outer periphery of the center electrode 14M, and a glass coat 14G is directly formed on the plane of the pedestal 11 (see FIG. 1).

The pedestal portion 11 is provided with six holes 11A1 to 11A6 for forming through holes or introducing the air as required. The holes 11A1 to 11A6 are formed to penetrate the pedestal 11.
The hole 11A1 is formed in the region of the central electrode 14M. The hole 11A1 is formed away from the center of the circle of the central electrode 14M in relation to a circuit (not shown) disposed on the opposite side of the pedestal 11.
The hole 11A2 is formed in a region between the inner periphery of the reference electrode 14R and the outer periphery of the center electrode 14M.
The hole 11A3 is formed to cover the outer peripheral edge of the reference electrode 14R. The reference electrode 14R has an enlarged portion 14R1 formed concentrically with the center of the hole 11A3.
The hole 11A4 is formed radially away from the outer periphery of the reference electrode 14R in the direction opposite to the center electrode 14M of the hole 11A3.
The holes 11A5 and 11A6 are formed in the region where the bonding glass 13 is provided.

The positional relationship between the reference electrode 14R and the holes 11A3 and 11A4 is shown in FIG.
In FIG. 3A, a part of the inner peripheral edge of the enlarged portion 14R1 in which the hole 11A3 is formed protrudes from the inner peripheral edge of the reference electrode 14R toward the center of the pedestal 11, and one of the outer peripheral edges A portion protrudes from the outer peripheral edge of the reference electrode 14R toward the outer diameter of the pedestal portion 11. The area in which the bonding glass 13 is formed is cut in an arc shape so as to avoid the protruding portion of the enlarged portion 14R1.
In FIG. 3B, the hole 11A4 is formed apart from the outer peripheral edge of the reference electrode 14R. The area in which the bonding glass 13 is formed is cut in an arc shape so as to avoid the hole 11A4.

In FIG. 4, a plane facing the pedestal 11 of the diaphragm 12 is shown.
In FIG. 4, the first electrode 15 </ b> C <b> 1 is a circle whose center of circle coincides with the central portion of the diaphragm portion 12. The diameter dimension of the first electrode 15C1 is 7 mm, which is the same as the diameter MD of the central electrode 14M.
The second electrode 15C2 is disposed concentrically with the first electrode 15C1. The second electrode 15C2 has a value (e.g., 17 mm) smaller than the inner diameter of the reference electrode 14R and an outer diameter CD2 the same value (e.g. 19 mm) as the outer diameter RD2 of the reference electrode. is there. That is, the second electrode 15C2 is annularly formed like the reference electrode 14R, but the dimension in the radial direction (width dimension) is set larger than the dimension in the radial direction of the reference electrode 14R. In the present embodiment, as long as the dimension in the radial direction of the second electrode 15C2 is set larger than the dimension in the radial direction of the reference electrode 14R, the configuration is not limited to that described above. The outer diameter CD2 of 15C2 may be a value larger than the outer diameter RD2 of the reference electrode.

The dimension CD between the outer periphery of the first electrode 15C1 and the inner periphery of the second electrode 15C2 is the surface on which the pedestal side electrode portion 14 of the pedestal portion 11 is formed and the surface on which the common electrode 15C of the diaphragm portion 12 is formed It is ten times or more of the dimension L between 12B. For example, assuming that CD = (17 mm−7 mm) / 2 = 5 mm and L = 10 μm, the magnification is 500 times. If the ratio of the dimension L to the dimension CD is less than 10 times, the effect of separating the first electrode 15C1 and the second electrode 15C2 is not sufficient, and the distance between the center electrode 14M and the first electrode 15C1 and the reference electrode The degree of interference between the electrostatic capacitances generated between 14 R and the second electrode 15 C 2 is increased.
A linear conductive portion 15D is connected to the first electrode 15C1 and the second electrode 15C2. The conductive portion 15D is disposed such that two places are linear with the first electrode 15C1 interposed therebetween. The dimension along the longitudinal direction of the conductive portion 15D is a dimension CD between the outer periphery of the first electrode 15C1 and the inner periphery of the second electrode 15C2, and the dimension (width dimension) orthogonal to the longitudinal direction is 0.3 mm It is an extent.

An electrode lead-out portion 15E is connected to a part of the outer peripheral edge of the second electrode 15C2. The electrode lead-out portion 15E is formed along the longitudinal direction of the conductive portion 15D, and has a linear base 15E1 connected to the second electrode 15C2 and a tip 15E2 connected to the base 15E1. The dimension (width dimension) orthogonal to the longitudinal direction of the base 15E1 is a value larger than the width dimension of the conductive portion 15D, for example, 1 mm. The tip portion 15E2 has a planar rectangular shape, and the width dimension thereof is larger than the width dimension of the base portion 15E1.
In the present embodiment, the diaphragm-side electrode unit 15 is configured to include the common electrode 15C, the conductive unit 15D, and the electrode extraction unit 15E.
The conductive portion 15D and the electrode lead-out portion 15E are formed of the same material as the common electrode 15C and in the same procedure as the common electrode 15C. The thickness dimension of the conductive portion 15D and the electrode lead-out portion 15E is the same as the thickness dimension of the common electrode 15C.

The enlarged view of the electrode extraction part 15E is shown by FIG. 5 (A). In FIG. 5A, a connecting portion between the base 15E1 of the electrode extraction portion 15E and the second electrode 15C2 is a curved portion R. Similarly, a curved portion R is formed at a connection portion between the base portion 15E1 and the tip end portion 15E2.
FIG. 5B shows an enlarged view of the conductive portion 15D. In FIG. 5B, curved portions R are formed in the connection portion between the first electrode 15C1 and the second electrode 15C2 of the conductive portion 15D.

In the first embodiment, the following effects can be achieved.
(1) The pedestal side electrode portion 14 has a central electrode 14M and an annular reference electrode 14R spaced apart from the outer peripheral edge of the central electrode 14M, and the diaphragm side electrode portion 15 has a common electrode 15C. The common electrode 15C has a first electrode 15C1 facing the central electrode 14M, and an annular second electrode 15C2 which is disposed apart from the outer peripheral edge of the first electrode 15C1 and faces the reference electrode 14R. Since the central electrode 14M and the first electrode 15C1 face each other and the reference electrode 14R and the second electrode 15C2 face each other, there is a gap between the first electrode 15C1 and the second electrode 15C2 in which no electrode is formed. Therefore, the interference between the electrostatic capacitance generated between the center electrode 14M and the first electrode 15C1 and the electrostatic capacitance generated between the reference electrode 14R and the second electrode 15C2 can be reduced, so detection of the sensor module An error can be suppressed.

(2) The dimension CD between the first electrode 15C1 and the second electrode 15C2 is such that the surface 11B on which the pedestal side electrode portion 14 of the pedestal portion 11 is formed and the diaphragm side electrode portion 15 of the diaphragm portion 12 are formed Since the dimension L between the surface 12B and the surface 12B is 10 times or more, the effect of separating the first electrode 15C1 and the second electrode 15C2 is sufficient, and electrostatic generated between the central electrode 14M and the first electrode 15C1 Interference between the capacitance and the capacitance generated between the reference electrode 14R and the second electrode 15C2 can be suppressed.

(3) Since the second electrode 15C2 is larger in radial dimension than the reference electrode 14R, the center electrode 14M and the first electrode are attached even if the second electrode 15C2 is attached with a deviation from the position where the second electrode 15C2 correctly faces the reference electrode 14R. It is possible to suppress the interference between the capacitance generated between 15C1 and the capacitance generated between the reference electrode 14R and the second electrode 15C2.

(4) Since the linear conductive portion 15D is connected to the first electrode 15C1 and the second electrode 15C2, a sufficient effect as the common electrode 15C can be obtained. Since the conductive portion 15D is linear, also from this point, the capacitance generated between the center electrode 14M and the first electrode 15C1, and the capacitance generated between the reference electrode 14R and the second electrode 15C2 Interference can be suppressed.

(5) Since the conductive portion 15D is linear, the area of the conductive portion 15D provided between the first electrode 15C1 and the second electrode 15C2 can be made smaller than when the conductive portion 15D is curved. It is possible to reduce electrostatic capacitance interference more effectively.

(6) The width dimension of the conductive portion 15D is smaller than the width dimension of the second electrode 15C2 to make it the minimum necessary width dimension, so from this point as well, the area of the conductive portion 15D can be reduced Capacitance interference can be suppressed more effectively.

(7) The conductive portion 15D is disposed in two places in a straight line with the first electrode 15C1 interposed therebetween. Therefore, even if the conductive portion 15D in one of the two places is cut, the remaining 1 Since the conductive portion 15D at the portion is in a state in which the first electrode 15C1 and the second electrode 15C2 are connected, the effect as the common electrode 15C can be made sufficient.

Second Embodiment
A second embodiment of the present invention will be described based on FIG. 6 to FIG.
The second embodiment differs from the first embodiment in that a shield electrode is provided on the pedestal 11, and the other configuration is the same as the first embodiment. In the description of the second embodiment, the same components as in the first embodiment are denoted by the same reference numerals, and the description will be omitted or simplified.
FIG. 6 shows the entire configuration of the sensor module 20 according to the second embodiment, and is a view corresponding to FIG.

In FIG. 6, the sensor module 20 is configured to include the pedestal 11, the diaphragm 12, and the bonding glass 13. A pedestal side electrode portion 24 is provided on the surface of the pedestal portion 11 facing the diaphragm portion side. The pedestal-side electrode portion 24 is formed by printing and applying Ag—Pd paste on the flat surface of the pedestal portion 11 and then firing the paste.
The pedestal side electrode unit 24 includes a shield electrode 24S in addition to the center electrode 14M and the reference electrode 14R.

A plane facing the diaphragm portion 12 of the pedestal portion 11 is shown in FIG.
In FIG. 7, the shield electrode 24S includes an annular small diameter shield electrode 24SA provided between the center electrode 14M and the reference electrode 14R and an annular large diameter shield electrode 24SB provided on the outer peripheral side of the reference electrode 14R. Prepare.
The small diameter shield electrode 24SA is disposed concentrically with the central electrode 14M, and the inner circumferential diameter SA1 is, for example, 7.5 mm, and the outer circumferential diameter SA2 is, for example, 17 mm.
The large diameter shield electrode 24SB is disposed concentrically with the central electrode 14M, and the inner peripheral diameter SB1 is, for example, 20 mm, and the outer peripheral diameter SB2 is, for example, 27 mm.
Electrodes are formed in the region between the central electrode 14M and the small diameter shield electrode 24SA, the region between the small diameter shield electrode 24SA and the reference electrode 14R, and the region between the reference electrode 14R and the large diameter shield electrode 24SB. Instead, the glass coat 14G is directly formed on the flat surface of the pedestal 11 (see FIG. 6).

The positional relationship between the reference electrode 14R and the holes 11A3 and 11A4 is shown in FIG.
In FIG. 8A, a part of the inner peripheral edge of the enlarged portion 14R1 in which the hole 11A3 is formed protrudes from the inner peripheral edge of the reference electrode 14R toward the center of the pedestal 11, and one of the outer peripheral edge A portion protrudes from the outer peripheral edge of the reference electrode 14R toward the outer diameter of the pedestal portion 11. The small diameter shield electrode 24SA and the large diameter shield electrode 24SB are cut in an arc shape so as to avoid the protruding portion of the enlarged portion 14R1.
In FIG. 8B, the hole 11A4 is formed apart from the outer peripheral edge of the reference electrode 14R. The large diameter shield electrode 24SB is cut in an arc shape so as to avoid the hole 11A4.

In the second embodiment, in addition to the same effects as (1) to (7) in the first embodiment, the following effects can be obtained.
(8) Since the shield electrodes 24SA and 24SB are respectively provided on the inner peripheral side and the outer peripheral side sandwiching the reference electrode 14R, the interference of the electrostatic capacitance can be reduced from the shielding effect.
(9) Even if high-humidity air intervenes between the center electrode 14M and the reference electrode 14R, it is blocked by the shielding effect of the small-diameter shield electrode 24SA on the inner peripheral side of the reference electrode 14R. It can be expected that the detection error can be suppressed.

Third Embodiment
A third embodiment of the present invention will be described based on FIG.
The third embodiment is different from the second embodiment in that the shield electrode is provided not only to the pedestal portion but also to the diaphragm portion, and the other configuration is the same as the first embodiment and the second embodiment. In the description of the third embodiment, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and the description will be omitted or simplified.
FIG. 9 shows the entire configuration of the sensor module 30 according to the third embodiment, and is a view corresponding to FIG.
In FIG. 9, the sensor module 30 includes the pedestal 11, the diaphragm 12, and the bonding glass 13. A pedestal side electrode portion 24 is provided on the surface of the pedestal portion 11 facing the diaphragm portion side.

A shield electrode 35S is provided on the surface of the diaphragm 12 facing the pedestal side. The shield electrode 35S is formed in a circular shape having an outer diameter of the same dimension as the inner circumferential diameter of the bonding glass 13.
An insulating member 31 is provided on the entire surface including the flat surface of the shield electrode 35S on the surface of the diaphragm 12 on the pedestal side. The insulating member 31 is formed of glass.
A common electrode 15C, a conductive portion 15D, and an electrode lead-out portion 15E are provided on a plane of the insulating member 31 which faces the pedestal portion 11. In FIG. 9, the conductive portion 15D and the electrode lead-out portion 15E are not shown. The planar shapes of the common electrode 15C, the conductive portion 15D, and the electrode lead-out portion 15E are the same as those shown in FIG. In the present embodiment, the diaphragm side electrode unit 35 is configured to include the shield electrode 35S, the common electrode 15C, the conductive portion 15D, and the electrode lead-out portion 15E. The shield electrode 35S is formed in the same manner as the common electrode 15C, the conductive portion 15D, and the electrode lead-out portion 15E.

In the third embodiment, in addition to the same effects as (1) to (9) in the second embodiment, the following effects can be obtained.
(10) The common electrode 15C, the conductive portion 15D and the electrode lead-out portion 15E are formed on the insulating member 31 provided on the surface of the diaphragm portion 12 facing the pedestal portion 11, and the common electrode 15C of the insulating member 31 is conductive Since the shield electrode 35S is provided on the surface opposite to the surface on which the portion 15D and the electrode extraction portion 15E are formed, the shielding effect can reduce the interference of the electrostatic capacity, and the diaphragm portion 12 Even if the liquid contact side of the liquid is filled with a conductive substance such as water, the influence can be reduced, and it can be expected that the detection error can be suppressed.
(11) The center electrode 14M, the reference electrode 14R, and the diaphragm side electrode portion by the small diameter shield electrode 24SA and the large diameter shield electrode 24SB provided on the inner and outer peripheral sides sandwiching the reference electrode 14R and the shield electrode 35S. Since the detection part which consists of 15 is enclosed by shield electric potential, it is hoped that the malfunction and detection error due to the radioactive and conductive electromagnetic noises can be suppressed.

Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like as long as the object of the present invention can be achieved are included in the present invention.
For example, in each of the above embodiments, the pedestal side electrode unit 14 includes the central electrode 14M and the reference electrode 14R, and the diaphragm side electrode unit 15 includes the common electrode 15C. The electrode portion 14 may have a common electrode 15C, and the diaphragm side electrode portion 15 may have a center electrode 14M and a reference electrode 14R.

  The conductive portion 15D may not be linear, and may be a curve. Furthermore, the conductive portion 15D is not necessarily required. Even in the case where the conductive portions 15D are provided, the conductive portions 15D are not limited to those provided in two places, and may be only one place or three or more places.

  10, 20, 30 ... sensor module, 11 ... pedestal part, 12 ... diaphragm part, 14, 24 ... pedestal side electrode part, 14M ... central electrode, 14R ... reference electrode, 15, 35 ... diaphragm side electrode part, 15C ... common Electrode 15C1 First electrode 15C2 Second electrode 15D Conducting portion 24S, 35S Shielding electrode 31 Insulating member

Claims (5)

A pedestal portion, a diaphragm portion provided on the pedestal portion, a pedestal side electrode portion provided on the pedestal portion, and a diaphragm side electrode portion disposed on the diaphragm portion facing the pedestal side electrode portion; Equipped with
The pedestal-side electrode portion has a central electrode disposed at a central portion, and an annular reference electrode disposed away from the outer peripheral edge of the central electrode,
Before SL diaphragm-side electrode portion includes a common electrode,
The common electrode may possess a first electrode facing the center electrode, a second electrode of the annular positioned away from the outer peripheral edge of the first electrode facing the reference electrode,
A linear conductive portion is connected between the first electrode and the second electrode,
The conductive portion is disposed so that two places are linear with respect to the first electrode, an electrode extraction portion is connected to a part of an outer peripheral edge of the second electrode, and the electrode extraction portion is A sensor module characterized in that it is formed along the longitudinal direction of the conductive portion . In the sensor module according to claim 1,
The dimension between the first electrode and the second electrode is the dimension between the surface on which the pedestal side electrode portion of the pedestal portion is formed and the surface on which the diaphragm side electrode portion of the diaphragm portion is formed. A sensor module characterized in that it is 10 times or more. In the sensor module according to claim 1 or 2,
The sensor module, wherein the second electrode has a radial dimension larger than that of the reference electrode. The sensor module according to any one of claims 1 to 3 .
A shield electrode is provided on one of the pedestal side electrode portion and the diaphragm side electrode portion. In the sensor module according to claim 4 ,
The central electrode, the reference electrode, and the shield electrode are formed on the pedestal portion,
The common electrode is formed on an insulating member provided on the surface of the diaphragm facing the pedestal, and the shield is provided on the surface of the insulating member opposite to the surface on which the common electrode is formed. A sensor module characterized in that a shield electrode different from the electrode is provided.

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