Pressure sensor
阅读说明:本技术 压力传感器 (Pressure sensor ) 是由 滨崎良平 于 2019-01-31 设计创作,主要内容包括:压力传感器具有:基体构件(12);固定电极(14),其设于基体构件(12);隔板(16),其与固定电极(14)隔开间隔地相对设置并且具有挠性和导电性;电介质体(20),其设于固定电极(14)并且与隔板(16)相对;以及接触限制构件(18b),其与隔板(16)接触从而限制电介质体(20)的一部分与隔板(16)的接触。(The pressure sensor includes: a base member (12); a fixed electrode (14) provided on the base member (12); a separator (16) which is disposed opposite to the fixed electrode (14) with a space therebetween and has flexibility and conductivity; a dielectric body (20) provided on the fixed electrode (14) and facing the separator (16); and a contact restriction member (18b) that comes into contact with the separator (16) so as to restrict contact of a part of the dielectric body (20) with the separator (16).)
1. A pressure sensor, wherein,
the pressure sensor includes:
a base member;
a fixed electrode provided on the base member;
a separator which is disposed opposite to the fixed electrode with a space therebetween and has flexibility and conductivity;
a dielectric body provided on the fixed electrode and opposed to the separator; and
a contact restricting member that contacts the partition plate to restrict a portion of the dielectric body from contacting the partition plate.
2. The pressure sensor of claim 1,
the region of the dielectric body that can be in contact with the partition plate has a shape having a constricted portion that sandwiches a central portion of the dielectric body that faces a central portion of the partition plate.
3. The pressure sensor of claim 1 or 2,
the region of the dielectric body that can be in contact with the partition plate has a shape having portions with different linear distances from the center to the outer peripheral portion.
4. The pressure sensor according to any one of claims 1 to 3,
the region of the dielectric body that can be in contact with the separator has an outer shape formed by two arcs protruding outward and two arcs protruding inward.
5. The pressure sensor according to any one of claims 1 to 3,
the region of the dielectric body that can be in contact with the separator has an outer shape formed by two parallel straight lines facing each other and two arcs projecting inward and facing each other.
6. The pressure sensor according to any one of claims 1 to 3,
the dielectric body has a substantially cross-shaped region that can be in contact with the partition plate.
7. The pressure sensor according to any one of claims 1 to 6,
the contact restriction member includes a pair of 1 st contact restriction members facing each other with the dielectric body interposed therebetween in a 1 st direction orthogonal to a facing direction of the partition plate and the dielectric body.
8. The pressure sensor of claim 7,
the contact restriction member includes a pair of 2 nd contact restriction members facing each other with the dielectric body interposed therebetween in a 2 nd direction orthogonal to the facing direction and the 1 st direction.
9. The pressure sensor according to any one of claims 1 to 8,
the dielectric body may have any one of a circular shape, a square shape, and a rectangular shape.
10. The pressure sensor according to any one of claims 1 to 9,
the partition plate is provided to the base member via a support member that supports an outer peripheral edge portion of the partition plate,
the contact regulating member is provided on the support member as a protruding portion that protrudes inward from the support member toward the center of the dielectric body.
11. The pressure sensor of claim 10,
the pair of protrusions is provided so as to face each other with the dielectric body interposed therebetween in a direction orthogonal to a facing direction of the partition plate and the dielectric body.
Technical Field
The present invention relates to a pressure sensor for measuring pressure such as air pressure.
Background
Conventionally, as a capacitance type pressure sensor, for example, a contact mode pressure sensor is known as described in patent document 1. Such a contact mode pressure sensor includes a fixed electrode, a diaphragm (spacer) that is disposed at a distance from the fixed electrode and flexes when subjected to pressure, and a dielectric film (dielectric body) that is provided on the fixed electrode and faces the spacer. First, when the pressure acts on the separator to deflect the separator, the distance between the fixed electrode and the separator decreases and the electrostatic capacitance between the fixed electrode and the separator increases. After the spacer is brought into contact with the dielectric body, that is, in the contact mode, the increase in the contact area of the dielectric body with the spacer increases the electrostatic capacitance between the fixed electrode and the spacer. With such a pressure-capacitance characteristic, the contact mode pressure sensor calculates a pressure from the electrostatic capacitance value and outputs the calculation result as a pressure measurement value.
Disclosure of Invention
Problems to be solved by the invention
However, in the case of the pressure sensor described in patent document 1, the linearity of the change in the capacitance with respect to the change in the pressure is low after the spacer comes into contact with the dielectric body. Therefore, the calculation formula for calculating the pressure measurement value from the electrostatic capacitance value is complicated and calculation accuracy is low. As a result, the measurement accuracy of the pressure sensor (calculation accuracy of the pressure) is low.
Therefore, an object of the present invention is to provide a pressure sensor capable of measuring a pressure with high accuracy by obtaining a higher linearity of a change in electrostatic capacitance between a fixed electrode and a diaphragm with respect to a change in pressure acting on the diaphragm.
Means for solving the problems
In order to solve the above technical problem, according to claim 1 of the present invention,
provided is a pressure sensor having:
a base member;
a fixed electrode provided on the base member;
a separator which is disposed opposite to the fixed electrode with a space therebetween and has flexibility and conductivity; a dielectric body provided on the fixed electrode and opposed to the separator; and
a contact restricting member that contacts the partition plate to restrict a portion of the dielectric body from contacting the partition plate.
According to claim 2 of the present invention, there is provided the pressure sensor according to claim 1, wherein,
the region of the dielectric body that can be in contact with the partition plate has a shape having a constricted portion that sandwiches a central portion of the dielectric body that faces a central portion of the partition plate.
According to claim 3 of the present invention, there is provided the pressure sensor according to claim 1 or 2, wherein,
the region of the dielectric body that can be in contact with the partition plate has a shape having portions with different linear distances from the center to the outer peripheral portion.
According to claim 4 of the present invention, there is provided the pressure sensor according to any one of claims 1 to 3, wherein,
the region of the dielectric body that can be in contact with the separator has an outer shape formed by two arcs protruding outward and two arcs protruding inward.
According to claim 5 of the present invention, there is provided the pressure sensor according to any one of claims 1 to 3, wherein,
the region of the dielectric body that can be in contact with the separator has an outer shape formed by two parallel straight lines facing each other and two arcs projecting inward and facing each other.
According to claim 6 of the present invention, there is provided the pressure sensor according to any one of claims 1 to 3, wherein,
the dielectric body has a substantially cross-shaped region that can be in contact with the partition plate.
According to claim 7 of the present invention, there is provided the pressure sensor according to any one of claims 1 to 6, wherein,
the contact restriction member includes a pair of 1 st contact restriction members facing each other with the dielectric body interposed therebetween in a 1 st direction orthogonal to a facing direction of the partition plate and the dielectric body.
According to an 8 th aspect of the present invention, there is provided the pressure sensor according to the 7 th aspect, wherein,
the contact restriction member includes a pair of 2 nd contact restriction members facing each other with the dielectric body interposed therebetween in a 2 nd direction orthogonal to the facing direction and the 1 st direction.
According to a 9 th aspect of the present invention, there is provided the pressure sensor according to any one of the 1 st to 8 th aspects, wherein,
the dielectric body may have any one of a circular shape, a square shape, and a rectangular shape.
According to a 10 th aspect of the present invention, there is provided the pressure sensor according to any one of the 1 st to 9 th aspects, wherein,
the partition plate is provided to the base member via a support member that supports an outer peripheral edge portion of the partition plate,
the contact regulating member is provided on the support member as a protruding portion that protrudes inward from the support member toward the center of the dielectric body.
According to an 11 th aspect of the present invention, there is provided the pressure sensor of the 10 th aspect, wherein,
the pair of protrusions is provided so as to face each other with the dielectric body interposed therebetween in a direction orthogonal to a facing direction of the partition plate and the dielectric body.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide a pressure sensor in which a change in electrostatic capacitance between a fixed electrode and a diaphragm with respect to a change in pressure acting on the diaphragm can obtain higher linearity, thereby enabling pressure to be measured with high accuracy.
Drawings
Fig. 1 is a perspective view of a pressure sensor element of a pressure sensor according to embodiment 1 of the present invention.
Fig. 2 is a partially exploded perspective view of a pressure sensor element of the pressure sensor according to embodiment 1 of the present invention.
Fig. 3A is a sectional view of the pressure sensor element taken along line a-a of fig. 2.
Fig. 3B is a sectional view of the pressure sensor element taken along line B-B of fig. 2.
Fig. 4 is a schematic configuration diagram of a pressure sensor according to embodiment 1 of the present invention.
Fig. 5 is a diagram showing pressure-capacitance characteristics of the pressure sensor element included in the pressure sensor according to embodiment 1 of the present invention.
Fig. 6A is a sectional view of the pressure sensor element along the line a-a of fig. 2 in a state where pressure is applied.
Fig. 6B is a sectional view of the pressure sensor element taken along the line B-B of fig. 2 in a state where pressure is applied.
Fig. 7 is a plan view showing a contactable region between the diaphragm and the dielectric body of the pressure sensor element included in the pressure sensor according to embodiment 1 of the present invention.
Fig. 8 is a plan view showing a change in the contact area between the diaphragm and the dielectric body due to an increase in pressure acting on the diaphragm in the pressure sensor element included in the pressure sensor according to embodiment 1 of the present invention.
Fig. 9 is a diagram showing a relationship between a change in pressure acting on the diaphragm and a change in contact area between the diaphragm and the dielectric body in the pressure sensor element included in the pressure sensor according to embodiment 1 of the present invention.
Fig. 10A is a plan view of a pressure sensor element included in the pressure sensor according to embodiment 2 of the present invention, with a diaphragm removed.
Fig. 10B is a plan view showing a contactable area between the diaphragm and the dielectric body of the pressure sensor element included in the pressure sensor according to embodiment 2 of the present invention.
Fig. 11A is a plan view of a pressure sensor element included in the pressure sensor according to embodiment 3 of the present invention, with a diaphragm removed.
Fig. 11B is a plan view showing a contactable area between the diaphragm and the dielectric body of the pressure sensor element included in the pressure sensor according to embodiment 3 of the present invention.
Fig. 12A is a plan view of a pressure sensor element included in the pressure sensor according to embodiment 4 of the present invention, with a diaphragm removed.
Fig. 12B is a plan view showing a contactable area between the diaphragm and the dielectric body of the pressure sensor element included in the pressure sensor according to embodiment 4 of the present invention.
Detailed Description
Embodiments of the present invention will be described below with reference to the drawings.
Fig. 1 is a perspective view of a pressure sensor element of a pressure sensor according to embodiment 1 of the present invention. Fig. 2 is a partially exploded perspective view of a pressure sensor element of the pressure sensor according to the present embodiment. Fig. 3A is a sectional view taken along line a-a in fig. 2, and fig. 3B is a sectional view taken along line B-B in fig. 2. The X-Y-Z orthogonal coordinate system shown in the drawings is for easy understanding of the present invention, and is not intended to limit the present invention.
As shown in fig. 1 and 2, the
The
As shown in fig. 3A and 3B, the fixed
The
The
The
Fig. 4 is a schematic configuration diagram of the pressure sensor according to the present embodiment.
As shown in fig. 4, the pressure sensor 30 has a
The fixed
The sensor controller 40 is configured to calculate an output pressure value Pout as a detected value of the pressure received by the
Specifically, the sensor controller 40 has a capacitance detection section 42, and the capacitance detection section 42 detects the capacitance between the fixed
The electrostatic capacitance detecting portion 42 is formed of an electrostatic capacitance type sensor that detects electrostatic capacitance between the fixed
The storage unit 44 is a storage device such as a memory, and stores a correction expression Eq (calculation expression) for correcting the capacitance detected by the capacitance detection unit 42 and calculating the output pressure value Pout. The correction expression Eq for calculating the output pressure value Pout is a function of the electrostatic capacitance based on the pressure-capacitance characteristic of the
The pressure calculation unit 46 is, for example, a processor capable of acquiring the capacitance detected by the capacitance detection unit 42 as a capacitance signal, acquiring the correction expression Eq from the storage unit 44 as correction expression data, and calculating the output pressure value Pout based on the capacitance signal and the correction expression data. The processor calculates the output pressure value Pout by executing a program stored in the storage unit 44 for correcting the capacitance detected by the capacitance detection unit 42 using the correction equation Eq, for example.
Fig. 5 is a diagram showing pressure-capacitance characteristics of the pressure sensor element included in the pressure sensor of the present embodiment. The operation of the pressure sensor 30 will be described with reference to the pressure-capacitance characteristic of the
In the pressure sensor 30, first, when a pressure is applied to the
When the pressure applied to the
Preferably, as shown in fig. 5, in the contact mode, the linearity of the change in the electrostatic capacitance between the fixed
In the present embodiment, as shown in fig. 2, the
Specifically, the pair of
The pair of
Fig. 6A and 6B are cross-sectional views of the
As shown in fig. 6A, at a portion of the
On the other hand, as shown in fig. 6B, in the
That is, as shown in fig. 7, the pair of
Fig. 8 is a plan view showing a change in the contact area between the diaphragm and the dielectric body due to an increase in pressure acting on the diaphragm in the pressure sensor element included in the pressure sensor according to the present embodiment. In fig. 8, the contact region CR is indicated by cross hatching. As shown in fig. 8, the contact region CR where the opposing
Fig. 9 is a diagram showing a relationship between a change in pressure acting on the diaphragm and a change in contact area between the diaphragm and the dielectric body in the pressure sensor element included in the pressure sensor of the present embodiment. In fig. 9, a solid line indicates the
As shown in fig. 9, in the pressure sensor element of the comparative example, as compared with the
This point is explained in detail. First, in the contact mode, since the pair of protruding
In the contact mode, regardless of whether there is a pair of the
In the
Therefore, as shown in fig. 9, in the
According to the present embodiment, it is possible to provide a pressure sensor in which a change in electrostatic capacitance between a fixed electrode and a diaphragm with respect to a change in pressure applied to the diaphragm can obtain higher linearity, thereby enabling pressure to be measured with high accuracy.
The present invention has been described above with reference to the above embodiments, but the embodiments of the present invention are not limited thereto.
For example, in the case of the above-described embodiment, as shown in fig. 1 and 2, the
Fig. 10A is a plan view of the pressure sensor element provided in the pressure sensor according to embodiment 2 of the present invention, with the diaphragm removed.
As shown in fig. 10A, the
In the
In the
However, the embodiments of the present invention are not limited thereto. Fig. 11A is a plan view of the pressure sensor element provided in the pressure sensor according to embodiment 3 of the present invention, with the diaphragm removed. As shown in fig. 11A, the pressure sensor element 210 according to embodiment 3 is rectangular when viewed in the direction in which the unillustrated partition plate and the dielectric body 220 face each other, that is, when viewed in the Z-axis direction), and the dielectric body 220 is also rectangular when viewed in the Z-axis direction. Fig. 11B is a plan view showing a contactable region between the diaphragm and the dielectric body in the pressure sensor element included in the pressure sensor of the present embodiment. In fig. 11B, the contactable area ACR is indicated by cross hatching. As shown in fig. 11A and 11B, in the pressure sensor element 210, similarly to the
Fig. 12A is a plan view of the pressure sensor element provided in the pressure sensor according to embodiment 4 of the present invention, with the diaphragm removed.
As shown in fig. 12A, the pressure sensor element 310 of embodiment 4 has a square shape when viewed in the direction in which the unillustrated partition plate and the dielectric body 320 face each other, that is, when viewed in the Z-axis direction, and the dielectric body 320 also has a square shape when viewed in the Z-axis direction.
In the pressure sensor element 310, two pairs of protrusions 318b and 318c are provided on the support member 318. The two pairs of protruding portions 318b and 318c protrude inward from the inner wall surface 318a of the support member 318 toward the center of the dielectric body 320. The pair of protrusions 318b as the 1 st contact restriction member are provided so as to face each other with the dielectric element 320 interposed therebetween in the 1 st direction orthogonal to the Z-axis direction, which is the facing direction of the partition plate and the dielectric element 320. Specifically, the 1 st direction is one diagonal direction of the square-shaped dielectric body 320 when viewed in the Z-axis direction.
The other pair of protrusions 318c as the 2 nd contact regulating members are provided so as to oppose each other across the dielectric body 320 in the 2 nd direction orthogonal to the Z-axis direction, which is the opposing direction of the spacer and the dielectric body 320, and the 1 st direction, which is the opposing direction of the pair of protrusions 318 b. Specifically, the 2 nd direction is another diagonal direction of the square-shaped dielectric body 320 when viewed in the Z-axis direction.
Fig. 12B is a plan view showing a contactable region between the diaphragm and the dielectric body in the pressure sensor element included in the pressure sensor of the present embodiment. In fig. 12B, the contactable area ACR is indicated by cross hatching. As shown in fig. 12B, a contactable area ACR which can be contacted with the electrode surface of the separator and a non-contact area NCR which cannot be contacted with the electrode surface of the separator are formed in the opposing surface 320a of the dielectric body 320 by the pair of protrusions 318B and the other pair of protrusions 318 c. That is, the contactable region ACR has a shape having two constricted portions which are provided in mutually orthogonal directions with the central portion of the dielectric body 320 being sandwiched therebetween, the central portion being opposed to the central portion of the partition plate, in a plan view, that is, when viewed in the Z-axis direction, by the pair of protruding portions 318b and the other pair of protruding portions 318 c. That is, the contactable area ACR has a substantially cross shape in plan view, that is, a shape in which two outer shapes including two parallel straight lines facing each other and two arcs protruding inward facing each other are overlapped with each other in a direction perpendicular to each other. The contactable region ACR has a shape having portions with different linear distances from the center to the outer peripheral portion when viewed in plan view, that is, when viewed in the Z-axis direction.
In the pressure sensor element 310, similarly to the
In the case of embodiment 1 described above, as shown in fig. 2, the pair of
In the case of embodiment 1 described above, as shown in fig. 2, the
That is, the pressure sensor according to the embodiment of the present invention is a pressure sensor having a base member, a fixed electrode provided on the base member, a flexible and conductive spacer provided to face the fixed electrode with a space therebetween, a dielectric body provided on the fixed electrode and facing the spacer, and a contact regulating member that is in contact with the spacer and regulates contact between a part of the dielectric body and the spacer.
While the present invention has been described above with reference to a plurality of embodiments, it will be apparent to those skilled in the art that at least one embodiment may be combined with any one embodiment entirely or partially to form another embodiment of the present invention.
Industrial applicability
The present invention can be applied to an electrostatic capacitance type pressure sensor.
Description of the reference numerals
12. A base member; 14. a fixed electrode; 16. a partition plate; 18b, a protrusion; 20. a dielectric body.
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