JPH10239193A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small pressure sensor that can be manufactured by general technology requiring no expensive manufacturing facility and that can be changed in design easily. SOLUTION: The pressure sensor is provided with a component A where a resin film 1 formed with a conductive electrode 20 is bonded to a ring body 2 while being applied with tension in order to impart elasticity thereto, and a component B where at least a conductive electrode 30 is formed on a substrate 3. The electrodes 10, 30 are disposed oppositely through a interval and the ring body 2 is arranged on the substrate 3 of the component B and a potential difference is set between the electrodes 10, 30. When the film 1 is subjected to fluid pressure, the film 1 is deformed to cause a variation in the capacitance between the electrodes 10, 30 and the variation of capacitance is transduced into an electric signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor for measuring a fluid pressure by introducing a fluid.

2. Description of the Related Art As a pressure sensor, for example, there is a piezoresistive sensor as shown in FIG. In this pressure sensor, as shown in the figure, a diaphragm 91 is formed by etching at the center of a silicon substrate 90, and a piezoresistive element is formed on the diaphragm 91 by using a semiconductor manufacturing technique. A fluid is introduced from the port 92 so that a fluid pressure acts on the silicon substrate 90. In this sensor, a change in the resistance value of the piezoresistive element, which occurs when the fluid pressure acts on the diaphragm portion 91, is converted into a voltage output or the like via the lead pin 93 and a Wheatstone bridge circuit. It can be measured. However,
The piezoresistive pressure sensor has a problem in that it requires a complicated manufacturing technique of forming a piezoresistive element on the silicon substrate 90 and the manufacturing equipment is expensive. Although this problem can be solved to some extent by mass production, it is not easy to change the form of the silicon substrate 90 and the like due to a change in the design of the sensor. In addition, there is a pressure sensor having a thin metal diaphragm portion instead of forming the diaphragm portion 91 by etching the silicon substrate 90. However, this pressure sensor is very difficult to process the diaphragm portion. In addition, they are large and costly. Therefore, in recent years, there has been a demand for the development of a pressure sensor that can be manufactured by a general technology that does not require expensive manufacturing equipment and that can be easily changed in design.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pressure sensor which can be manufactured by a general technique which does not require a small and expensive manufacturing facility and which can be easily changed in design.

A pressure sensor according to the present invention comprises: a component A which is formed by fixing a resin film 1 on which a conductive electrode 10 is formed to a ring body 2 by applying tension so as to have elasticity; And a component B having at least a conductive electrode 30 formed on the substrate 3. The ring body 2 of the component A is placed on the substrate 3 of the component B in such a manner that the electrodes 10 and 30 face each other with a gap therebetween. And the electrodes 10, 3
A change in the capacitance between the electrodes 10 and 30 caused by deformation of the resin film 1 when a fluid pressure acts on the resin film 1 by applying a potential difference between zeros is converted into an electric signal. In the pressure sensor, it is assumed that the ring body 2 is made of a conductive metal and the ring body 2 and the electrode 10 are in an electrically connected state. Forming a land 31 having a characteristic, the ring body 2 and the land 31
Are in contact with each other so as to be in an electrically connected state. Here, the operation and the like when the configuration of the pressure sensor is adopted will be described in the section of the embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 shows a pressure sensor according to an embodiment of the present invention, in which a fluid is introduced into a housing 6 from a pressure inlet 61 to measure the pressure of the fluid. This pressure sensor basically includes a housing 6 and sensor components A and B incorporated in the housing 6 as shown in FIG. 1. Each component will be described in detail below. [Housing 6] As shown in FIG. 1, the housing 6 has a circular small-diameter portion 6a having a pressure introduction path 62.
And a circular enlarged portion 6b having a sensor component housing portion 63 having an open lower end. The sensor component housing portion 63 has a small diameter communicating with the pressure introduction passage 62 as shown in FIG. Hole 63a, medium diameter hole 63b, and large diameter hole 63c
And [Sensor Component A] As shown in FIG. 1, the sensor component A has a circular resin film 1 having an electrode 10 formed on almost the entire surface thereof, and has the same outer diameter as the resin film 1. The resin film 1 is fixed to the ring body 2 by applying tension to the resin film 1 so that the electrode 10 and the ring body 2 are in an electrically connected state. The electrode 10 is formed by depositing or applying a conductive substance to a film. The same applies to the electrodes 30 and lands 31 described later.
Here, the outer diameter of the sensor component A is made substantially coincident with the diameter of the medium-diameter hole 63b, and is fitted into the medium-diameter hole 63b as shown in FIG. [Sensor Component B] As shown in FIG. 1, the sensor component B is a circular electrode 3 covered with an insulating resist film 32 on a substrate 3 large enough to be accommodated in the large-diameter hole 63c.
0 and a circular ring-shaped land 31 surrounding the ring body 2. The land 31 is set to be substantially the same as the ring body 2 in plan view, and the electrode 30 is slightly smaller than the inner diameter of the ring body 2. It is set small. As shown in FIG. 1, a through hole h1 is arranged at the center of the electrode 30 on the substrate 3 and a hole h2 communicating with the through hole h1 is formed at the corresponding electrode 30 and insulating resist film 32. It has been formed. As shown in FIG. 1, the substrate 3 is provided with lead pins 4 for power supply and electric signal interface in the vicinity of the outer peripheral portion so as to penetrate the upper and lower surfaces, and between the electrodes 10 and 30 on the lower surface side. An electronic component 5 for detecting a change in the capacitance of the electronic component is attached. Here, the sensor component B is attached to the housing 6 by screws 7 as shown in FIG. 2, whereby the sensor component A is firmly held between the sensor component B and the housing 6. Then, as shown in FIG. 1, the medium-diameter / large-diameter holes 63b and 63c of the housing 6 are formed.
The sensor components A and B excluding the lead pins 4 are not exposed by filling the sealing material 8 with the sealing material 8. In this state, the ring body 2 and the land 31 are in electrical contact with each other, and the resin film 1 and the housing 6 have fluid tightness. [Regarding an embodiment in which a potential difference is provided between the electrodes 10 and 30] In this pressure sensor, a voltage is applied to the electrode 30 through the through hole h1 shown in FIG. 1 and the electrode 10 is grounded through the through hole h3. 10,
A potential difference is provided between 30. [Manufacturing of this pressure sensor] It is clear that the housing 6 and the sensor parts A and B can be manufactured by a general technique that does not require expensive manufacturing equipment, and in particular, a sensor corresponding to a diaphragm which has been difficult to process. Part A
It can be manufactured very simply (without difficult processing, etc.), can be easily manufactured small, and can be easily changed in design. In addition, these can be assembled only with the screw 7. [Method of Detecting Fluid Pressure of This Pressure Sensor ] In this pressure sensor PS, if the fluid pressure applied from the pressure inlet 61 shown in FIG. 3 is P1 and the surrounding pressure is P2, P1 ≠ P
At 2, the central portion of the resin film 1 is deformed into a concave shape shown by a two-dot chain line in FIG. 3 or a convex shape shown by a solid line in FIG. 3 according to the pressure difference between P1 and P2. At this time, the deformation of the resin film 1 is smooth because the through hole h1 and the hole h2 function as air passages. The deformation of the resin film 1 causes the capacitance between the electrodes 10 and 30 to appear as a change.
The change in the capacitance is detected by the electronic device 5. By converting the detected change in the capacitance into, for example, a change in the voltage, the change can be visually measured through an instrument or the like. [Other Embodiments] In the above embodiment, the ring body 2 is made of a conductive metal and the conductive land 31 is formed on the substrate 3 in order to ground the electrode 10 using the through hole h3. However, the electrode 10
Depending on the form of the ground, the ring body 2 may be formed of a non-conductive member and the land 31 may not be formed.

Since the configuration of the present invention is as described above, the following effects can be obtained. As is clear from the contents of the embodiments of the invention, it is apparent that a pressure sensor which can be manufactured by a general technique which does not require a small and expensive manufacturing facility and whose design can be easily changed can be provided.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of the pressure sensor taken in a longitudinal section at a portion different from FIG.

FIG. 3 is a sectional view showing a state in which a resin film is elastically deformed by a fluid pressure with respect to the pressure sensor.

FIG. 4 is a sectional view of a prior art piezoresistive pressure sensor.

[Explanation of symbols]

 A sensor component B sensor component 1 resin film 2 ring 3 substrate 10 electrode 30 electrode 31 land

Claims (2)

[Claims] 1. A component (A) comprising a resin film (1) on which a conductive electrode (10) is formed and fixed to a ring body (2) by applying tension so as to have elasticity, and a substrate (3). ) And a component (B) formed by forming at least a conductive electrode (30), and the electrodes (10) and (30) are opposed to each other with a gap provided therebetween. (2) is arranged on the substrate (3) of the component (B),
When a potential difference is applied between the electrodes (10) and (30) and a fluid pressure acts on the resin film (1), electrostatic force between the electrodes (10) and (30) caused by deformation of the resin film (1). A pressure sensor characterized in that a change in capacitance is converted into an electric signal. 2. The ring body (2) is made of a conductive metal and the ring body (2) and the electrode (10) are in an electrically connected state, while the electrode (30) on the substrate (3). A ring-shaped land (31) having conductivity is formed on the outer periphery of the ring body (2) and the land (3).
2. The pressure sensor according to claim 1, wherein the pressure sensor is in contact with (1) so as to be in an electrically connected state.