Pressure sensor and method based on capacitance resonance

Abstract

The invention discloses a pressure sensor based on capacitance resonance and a method. The pressure sensor comprises a control substrate and an induction substrate. The control substrate is located at the top of the capacitive strain gauge, a stress substrate is arranged at the bottom of the induction substrate, and the control substrate comprises a dot matrix formed by at least two dots; the induction substrate comprises a capacitive strain gauge; a controller is arranged outside the control substrate, and the controller is connected with all points in the dot matrix. Excitation signals do not need to be input externally, the measuring sensitivity of the pressure sensor is improved, and therefore the pressure sensor is suitable for more complex application scenes.

Description

Technical Field

[0001] The invention belongs to the field of pressure sensors and relates to a pressure sensor and a method based on capacitor resonance. Background Art

[0002] Most traditional pressure sensors convert physical quantities into analog quantities by changing the capacitance between strain gauges after an external force is applied, thereby changing the output analog voltage or current. However, the measurement range and sensitivity of such sensors are fixed and cannot adapt to complex environments.

[0003] Among the existing technologies for improving the sensitivity of pressure sensors through resonance, most of them are to change the resonance frequency by inputting an excitation signal, thereby improving the sensitivity. However, such sensors require the input of external signals, which is relatively complicated. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a pressure sensor and method based on capacitive resonance, which does not require an external input excitation signal, improves the sensitivity of the pressure sensor measurement, and is therefore suitable for more complex application scenarios.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A pressure sensor based on capacitive resonance, comprising a control substrate and a sensing substrate; The control substrate is located on the top of the capacitive strain gauge, and a force-bearing substrate is arranged at the bottom of the sensing substrate. The control substrate includes a dot matrix consisting of at least two points; the sensing substrate includes a capacitive strain gauge; a controller is arranged outside the control substrate, and the controller is connected to each point in the dot matrix.

[0006] Preferably, the control substrate and the sensing substrate are packaged by epoxy resin adhesive.

[0007] Preferably, a groove is provided on the stress-bearing substrate, and the groove corresponds to the position of the capacitive strain gauge.

[0008] Furthermore, the size of the groove is larger than the size of the capacitive strain gauge, and the depth of the groove is larger than the maximum deformation of the capacitive strain gauge.

[0009] Furthermore, the sensing substrate and the force-bearing substrate are packaged by epoxy resin adhesive.

[0010] Preferably, the dot matrix covers the corresponding area of ​​the capacitive strain gauge.

[0011] Preferably, the controller is provided with a plurality of buttons, the number of which is consistent with the number of dots in the dot matrix and which are connected in a one-to-one correspondence.

[0012] Preferably, the controller adopts MCU.

[0013] A capacitive resonance method of the pressure sensor includes the following process: When the pressure sensor is not working, the stress-bearing substrate is the cathode and the control substrate is the cathode. The controller converts the electrical properties of some points on the control substrate into anodes. At this time, the electrical properties of the control substrate and the stress-bearing substrate are opposite, and electrode induction occurs. The capacitive strain gauge of the induction substrate will be affected by a force, so that the effective length of the capacitive strain gauge will change, and the frequency of the pressure sensor will also change. By controlling the number of electrical conversions at the control points, the effective length of the capacitive strain gauge is adjusted, and the frequency of the pressure sensor is gradually made consistent with the characteristic frequency of the outside world until the pressure sensor reaches a resonant state with the outside world.

[0014] Preferably, the frequency of the pressure sensor is , where T is the tension, is the line density, and L is the length of the capacitive strain gauge.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention sets a control substrate, a sensing substrate, and a stress-bearing substrate, sets a dot matrix on the control substrate, sets a capacitive strain gauge on the sensing substrate, and forms a pressure sensor. A controller is set outside the pressure sensor, and the controller can control the electrode changes of the dot matrix, so that the control substrate and the stress-bearing substrate undergo electrode induction to make the sensing substrate stress-bearing, and the effective length of the capacitive strain gauge is controlled according to the change of the dot matrix, and the frequency of the pressure sensor is changed according to the effective length. In addition, the upper limit of the capacitance of the capacitive strain gauge can be changed by the above method, and the upper limit of the output signal is increased, thereby increasing the upper limit of the pressure detection. At the same time, when the frequency of the outside world is close to the frequency of the pressure sensor, the two send resonance, and the signal generated after the resonance will be amplified, thereby improving the sensitivity of the pressure sensor measurement, and then adapting to more complex application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of a pressure sensor based on capacitive resonance proposed in an embodiment of the present application; Figure 2 It is a schematic diagram of the structure of controlling a strain gauge based on a pressure sensor according to an embodiment of the present application.

[0017] The above drawings include the following reference numerals: 1-control substrate, 2-sensing substrate, 3-force substrate, 4-dot matrix, 5-capacitive strain gauge, 6-groove, 7-controller. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" used in this article includes any and all combinations of one or more related listed items. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0022] like Figure 1 As shown, the embodiment of the present application proposes a pressure sensor based on capacitive resonance, which mainly includes a control substrate 1, a sensing substrate 2 and a force-bearing substrate 3.

[0023] The control substrate 1 and the sensing substrate 2 , as well as the sensing substrate 2 and the force-bearing substrate 3 are packaged by epoxy resin adhesive.

[0024] The control substrate 1 includes a dot matrix 4 consisting of n points, and two capacitive strain gauges 5 are attached to the sensing substrate 2. The number is not specifically limited in this application, and the dot matrix 4 fully covers the corresponding area of ​​the capacitive strain gauge 5.

[0025] The stress-bearing substrate 3 is provided with a groove 6 adapted to strain gauges of different sizes, the size of the groove 6 is larger than the size of the capacitive strain gauge 5, and the depth of the groove 6 is larger than the maximum deformation of the capacitive strain gauge 5. When the strain gauge is stressed, the groove 6 is docked with the capacitive strain gauge 5, so that the stressed part can be fully deformed, preventing the sensor output error caused by incomplete or uneven deformation, thereby ensuring the accuracy and stability of the sensor.

[0026] A controller 7 is provided outside the control substrate 1, and an MCU (microcontroller unit) is specifically selected as the controller 7. The MCU adjusts the electrical property changes of the dot matrix 4 through a plurality of key controllers 7. The number of keys provided on the controller 7 is consistent with the number of points in the dot matrix 4, and each key controls the electrical state of the corresponding point in the dot matrix 4. By pressing different keys on the controller 7, the electrical property changes of different dot matrices 4 can be adjusted, thereby controlling the sensitivity and detection range of the pressure sensor.

[0027] The specific working principle of a pressure sensor based on capacitive resonance provided by this solution mainly includes: The controller 7 can control the electrical property changes of each point in the dot matrix 4 by controlling the button. When the pressure sensor is not working, the force-bearing substrate 3 is the cathode and the control substrate 1 is the cathode. When the button of the controller 7 is pressed, the electrical property of the corresponding dot matrix 4 on the control substrate 1 turns into the anode. At this time, the electrical properties of the control substrate 1 and the force-bearing substrate 3 are opposite, and electrode induction occurs. The capacitive strain gauge 5 of the induction substrate 2 will be affected by a force, and thus the effective length of the strain gauge will change.

[0028] In one implementation, in the above pressure sensor, when the effective length of the strain gauge changes, when the pressure sensor is subjected to an external force, the deformation of the strain gauge will change, and the corresponding upper limit of the capacitance value will increase. When the controller 7 controls different dot matrices 4 to increase the area of the strain gauge, more charges can be stored, and the upper limit of the capacitance value will also increase, thereby increasing the upper limit of the capacitance value of the pressure sensor, and then causing an increase in the upper limit of the output signal, increasing the upper limit of pressure detection.

[0029] In another implementation, in the above pressure sensor, when the effective length of the strain gauge changes, the frequency of the pressure sensor will also change. At the same time, when the frequency of the pressure sensor is close to or the same as the frequency of the external environment, the two resonate. At this time, the output signal of the pressure sensor will be enhanced, so the pressure sensor will have a higher sensitivity to this frequency of the external world. It can be obtained that by controlling the electrical properties of the points in different dot matrices 4 by the controller 7, the modulation of the sensitivity of the pressure sensor to different frequency signals in the external world can be realized.

[0030] Through this structure, the sensitivity and the range of the output signal of the pressure sensor at a specific frequency can be adjusted according to the requirements of the outside world. For example, when the external frequency is f0, the corresponding dot matrix 4 electrode change can be changed by controlling the control button, so as to change the effective length of the strain gauge on the induction plate, and then change the characteristic frequency of the pressure sensor to f0. At this time, the pressure sensor and the external environment resonate, thereby improving the sensitivity. At the same time, the change in the effective length of the strain gauge will also cause a change in the amount of deformation, thereby causing an increase in the upper limit of the capacitance value, and then causing an increase in the upper limit of the output signal, increasing the upper limit of pressure detection.

[0031] As Figure 2 shown, the specific principle of the resonance process is: The controller 7 controls the button X1, and the electrical property of the P1 point of the dot matrix 4 changes. At this time, the effective length is L1. When the button X2 is controlled, the electrical property of the P2 point of the dot matrix 4 changes. At this time, the effective length of the strain gauge is L2. According to different buttons, L1 < L2 can be controlled at this time. According to the formula , where T is the tension, is the line density, L is the length of the capacitive strain gauge 5, it can be obtained that the frequency f1>f2 at L1 at this time, and the characteristic frequency of the outside world is f2 at this time, that is, the X2 button needs to be controlled, so the current pressure sensor resonates with the outside world. When the resonance state is reached, the signal quality transmitted after the pressure sensor collects data is improved, thereby improving the sensitivity.

[0032] The specific principle of changing the output upper limit process is: when the control button X1, the electrical properties of point P1 of the dot matrix 4 undergo electrode changes, and the effective length at this time is L1; when the control button X2, the electrical properties of point P2 of the dot matrix 4 undergo electrode changes, and the effective length of the strain gauge is L2. The effective length of the strain gauge changes, which increases the area of ​​the strain gauge, so that it can store more charge, and the upper limit of the capacitance will also increase, thereby increasing the upper limit of the capacitance of the pressure sensor, which will cause the upper limit of the output signal to increase, and increase the upper limit of pressure detection.

[0033] In the pressure sensor based on capacitive resonance, the dot matrix 4 and the controller 7 are key components, which work together to achieve flexible control of the sensitivity, frequency response and detection range of the pressure sensor. The dot matrix 4 and the controller 7 in this embodiment are respectively introduced in detail below.

[0034] The dot matrix 4 is an electrical control network composed of multiple independent points arranged on the control substrate 1. Each point in the dot matrix 4 can independently control its electrical state, so that different areas can be selectively activated. The following are the main features and functions of the dot matrix 4: 1. Dot matrix 4 composition: The dot matrix 4 is composed of a plurality of evenly distributed points (P1, P2, P3, etc.), the number and arrangement of which can be flexibly designed according to application requirements. In actual operation, each point can be individually controlled by the controller 7, so that the pressure sensor has different sensitivities to changes in external forces in different areas, thereby achieving accurate response to external pressure.

[0035] 2. Electrical property change control: Each point can switch the electrical state (for example, from cathode to anode), thereby changing the electrical distribution between the control substrate 1 and the stress substrate 3. The electrical property change of the point will cause the electric field between the control substrate 1 and the stress substrate 3 to change, causing the capacitive strain gauge 5 on the sensing substrate 2 to have different degrees of stress and strain. This adjustability of the electrical state allows the pressure sensor to respond more flexibly to different external pressure and frequency signals in applications.

[0036] 3. Impact on strain gauges: The electrical change control of dot matrix 4 will indirectly affect the effective length of the strain gauge. By activating different points in the dot matrix 4, the effective length of the capacitive strain gauge 5 on the sensing substrate 2 can be changed, thereby adjusting the operating frequency or output upper limit of the pressure sensor. For example, after activating point P1, the effective length of the strain gauge becomes L1; after activating point P2, the length becomes L2. The dot matrix 4 control not only adjusts the physical parameters of the strain gauge, but also changes the operating frequency and capacitance upper limit of the pressure sensor.

[0037] In this embodiment, the dot matrix 4 actually refers to a plurality of independent electrode arrays arranged on the control substrate 1. Each "dot" in the dot matrix 4 is a small electrode, and the electrical state of these electrodes can be individually adjusted by the control circuit (such as switching from cathode to anode). In actual use, these dots are usually made of conductive materials (such as metals such as copper, aluminum or gold), forming a regularly arranged network of tiny electrodes, similar to pads or contact points on an electronic circuit board.

[0038] The dot matrix 4 uses multiple electrode contacts and deposits multiple small metal electrodes on the control substrate 1 to form an array. These electrodes are connected to the controller 7 (MCU) through wires, and the electrical state of each electrode can be independently changed under the operation of the controller 7.

[0039] Each point is connected to the MCU through a separate control line. The MCU controls the electrical changes of different electrode contacts to form the desired electric field distribution and control the sensitivity and frequency response of the pressure sensor.

[0040] In summary, the dot matrix 4 is a network composed of a plurality of independently controllable tiny electrode points (contact points). The electrical properties of the electrodes are individually adjusted by the controller 7, so that the pressure sensor can flexibly respond to external pressure and frequency changes.

[0041] MCU is the core controller of the pressure sensor system, responsible for adjusting the electrical state of the dot matrix. The following are the main functions of MCU: 1. Multi-button control: The MCU has a one-to-one correspondence with each point in the dot matrix 4 through multiple buttons. Each button controls the electrical state of a point, and the electrical properties of different points can be precisely controlled by pressing different buttons. The number of buttons on the controller 7 is consistent with the number of points in the dot matrix 4, so that each button can directly control the electrical state conversion of the corresponding point.

[0042] Since the frequency of the external environment at a fixed location remains unchanged, the frequency of the pressure sensor will not be too frequent. In this embodiment, the MCU can be manually controlled by an external host computer to gradually increase the number of button triggers and gradually adjust the frequency of the pressure sensor until the frequency of the pressure sensor is the same or nearly the same as the external frequency, and then stop the control to keep the state of dot matrix 4 unchanged at this time.

[0043] The MCU can also process adaptively. When the external environment changes, the external environment frequency value is written to the MCU in advance. The MCU gradually increases or presses the button trigger number, and gradually adjusts the pressure sensor frequency. The MCU judges the difference between the pressure sensor frequency and the external frequency in real time until the pressure sensor frequency is the same or nearly the same as the external frequency, stops the button trigger, and keeps the state of dot matrix 4 unchanged at this time.

[0044] 2. Electrical reversal: When the pressure sensor is in a static state, both the stress substrate 3 and the control substrate 1 are cathodes. When a control button is pressed, the corresponding dot matrix 4 points turn from cathode to anode, forming an electrical reversal effect. This electrical reversal will cause the electric field to change between the control substrate 1 and the stress substrate 3, and the capacitive strain gauge 5 on the sensing substrate 2 will be affected and deformed. This operation enables the MCU to achieve sensitive response of the pressure sensor to external pressure changes through simple electrical switching.

[0045] 3. Frequency and sensitivity adjustment: By controlling different buttons, the characteristic frequency of the pressure sensor can be adjusted. For example, when button X1 controls point P1 to activate, the corresponding frequency is f1; when button X2 controls point P2 to activate, the corresponding frequency is f2. If the external frequency is close to or consistent with the frequency of the pressure sensor, the two will resonate, enhancing the output signal of the pressure sensor and thus improving the sensitivity. By controlling different combinations of buttons, the MCU can make the pressure sensor reach the highest sensitivity at a specific frequency and respond sensitively to specific frequency signals.

[0046] 4. Adjustment of the upper limit of capacitance: When different buttons are pressed to activate different points of the dot matrix 4, the positions of electrical reversal on the control substrate 1 are different, and the effective length of the strain gauge also changes accordingly, increasing the surface area of ​​the strain gauge and thus increasing the charge storage capacity. This operation directly increases the upper limit of the capacitance of the pressure sensor, allowing the pressure sensor to work within a higher pressure range and increase its detection upper limit.

[0047] In general, the pressure sensor based on capacitor resonance can flexibly adjust the operating frequency, sensitivity and upper limit of the output signal of the pressure sensor by controlling the electrical changes of the dot matrix 4 on the substrate 1, thereby realizing accurate detection and adjustment of different external pressures and frequencies. This technology not only improves the adaptability of the pressure sensor, but also makes its performance in practical applications more accurate and reliable.

[0048] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0049] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0050] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0051] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0052] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

[0053] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined with reference to the above description, but rather with reference to the preceding claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A pressure sensor based on capacitive resonance, characterized in that: It comprises a control substrate (1) and a sensing substrate (2); The control substrate (1) is located on top of the capacitive strain gauge (5); a force-bearing substrate (3) is arranged at the bottom of the sensing substrate (2); the control substrate (1) includes a dot matrix (4) consisting of at least two points; the sensing substrate (2) includes a capacitive strain gauge (5); and a controller (7) is arranged outside the control substrate (1); the controller (7) is connected to each point in the dot matrix (4).

2. The capacitive resonance-based pressure sensor according to claim 1, characterized in that: The control substrate (1) and the sensing substrate (2) are packaged by epoxy resin adhesive.

3. The capacitive resonance-based pressure sensor according to claim 1, characterized in that: A groove (6) is provided on the stress-bearing substrate (3), and the position of the groove (6) corresponds to that of the capacitive strain gauge (5).

4. The capacitive resonance-based pressure sensor according to claim 3, characterized in that: The size of the groove (6) is greater than the size of the capacitive strain gauge (5), and the depth of the groove (6) is greater than the maximum deformation of the capacitive strain gauge (5).

5. The capacitive resonance-based pressure sensor according to claim 3, characterized in that: The sensing substrate (2) and the force-bearing substrate (3) are packaged by epoxy resin adhesive.

6. The capacitive resonance-based pressure sensor according to claim 1, characterized in that: The dot matrix (4) covers the corresponding area of ​​the capacitive strain gauge (5).

7. The capacitive resonance-based pressure sensor according to claim 1, characterized in that: The controller (7) is provided with a plurality of buttons, the number of which is consistent with the number of dots in the dot matrix (4) and which are connected in a one-to-one correspondence.

8. The capacitive resonance-based pressure sensor according to claim 1, characterized in that: The controller (7) adopts MCU.

9. A capacitive resonance method for a pressure sensor according to any one of claims 1 to 8, characterized in that: The process includes: When the pressure sensor is not working, the stress-bearing substrate (3) is the cathode and the control substrate (1) is the cathode. The controller (7) converts the electrical properties of some points on the control substrate (1) into anodes. At this time, the electrical properties of the control substrate (1) and the stress-bearing substrate (3) are opposite, and electrode induction occurs. The capacitive strain gauge (5) of the induction substrate (2) is acted upon by a force, so that the effective length of the capacitive strain gauge (5) changes, and the frequency of the pressure sensor also changes. The effective length of the capacitive strain gauge (5) is adjusted by controlling the number of electrical property conversions at the control points, thereby gradually making the frequency of the pressure sensor consistent with the characteristic frequency of the outside world, until the pressure sensor reaches a resonant state with the outside world.

10. The capacitor resonance method according to claim 9, characterized in that: The frequency of the pressure sensor is , where T is the tension, is the line density, and L is the length of the capacitive strain gauge (5).

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