Positioning and pressure detection integrated three-electrode sensor and manufacturing method thereof

Abstract

The invention relates to the technical field of sensors, in particular to a three-electrode sensor integrating positioning and pressure detection and a manufacturing method thereof, and the three-electrode sensor comprises a resistor positioning unit, a gasket, a piezoelectric unit and a packaging layer which are connected in sequence; wherein the resistor positioning unit is used for detecting a stressed position; the upper parts of the two gaskets are respectively connected to the edge of the resistor positioning unit, and the lower parts of the two gaskets are respectively connected to the edge of the piezoelectric unit, so that the resistor positioning unit and the piezoelectric unit form a cavity structure; the piezoelectric unit is used for detecting the magnitude of stress; the sensor can collect the pressure position and the pressure magnitude at the same time, has the advantages of being simple in structure, independent in signal and stable in performance, and has great application potential in multiple frontier fields such as flexible sensing, medical instruments and robot grabbing.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a three-electrode sensor integrating positioning and pressure detection and a manufacturing method thereof. Background Art

[0002] With the development of smart electronic devices, wearable devices, robotics, and medical health monitoring, the demand for flexible and integrated sensors is increasing.

[0003] Existing sensors can effectively detect a single physical quantity. Resistive sensors, capacitive sensors, and piezoelectric sensors can be used to detect pressure values; photoelectric and laser sensors, capacitive sensors, resistive sensors, and magnetic sensors can be used to detect position information; capacitive sensors are more sensitive to environmental and temperature changes; photoelectric positioning sensors require very precise structures and high measurement accuracy; resistive sensors have simple structures and high sensitivity; piezoelectric sensors show excellent performance in dynamic pressure detection; magnetic sensors are often used for non-contact measurement.

[0004] Most existing composite sensing technology solutions are to mix the position signal and the pressure signal into one, and transmit the composite signal through a composite single channel. However, such technical means have the following problems: the two signals are not completely independent, so signal decoupling requires a complex algorithm model with high computational cost, and the coupling during the transmission of multiple signals will reduce the overall performance of the sensor.

[0005] Therefore, existing composite sensors have problems such as output signal coupling, high cost, complex structure, and low sensitivity. Summary of the invention

[0006] In view of this, the present invention proposes a three-electrode sensor integrating positioning and pressure detection and a manufacturing method thereof to solve the above problems, including:

[0007] A three-electrode sensor integrating positioning and pressure detection, comprising a resistor positioning unit, a gasket, a piezoelectric unit, and a packaging layer connected in sequence; wherein the resistor positioning unit is used to detect the position of the force; the upper parts of the two gaskets are respectively connected to the edge of the resistor positioning unit, and the lower parts of the two gaskets are respectively connected to the edge of the piezoelectric unit, so that the resistor positioning unit and the piezoelectric unit form a cavity structure; the piezoelectric unit is used to detect the magnitude of the force;

[0008] A method for manufacturing a three-electrode sensor integrating positioning and pressure detection, used to manufacture the above-mentioned sensor, comprises the steps of:

[0009] S1, cleaning the film and cutting the film to obtain an insulating layer and a packaging layer;

[0010] S2. Clean the surface stains of the insulation layer and the packaging layer;

[0011] S3, coating the conductive mixed sensitive material on the lower surface of the insulating layer to form a resistance sensitive layer, drying, and attaching electrodes on the resistance sensitive layer to obtain a resistance positioning unit;

[0012] S4, preparing a piezoelectric material solution, polarizing the piezoelectric material solution and pouring it into a mold, drying and demoulding, to obtain a piezoelectric layer;

[0013] S5, attaching a layer of metal electrodes to each of the two surfaces of the piezoelectric layer to obtain a piezoelectric unit;

[0014] S6. Assemble the components from top to bottom in the order of resistor positioning unit, gasket, piezoelectric unit, and packaging layer; during the assembly process, two gaskets are used to fix the resistor positioning unit and the piezoelectric unit so that the two units do not contact each other when not working, and the non-contact parts form a cavity.

[0015] The beneficial effects of the present invention include:

[0016] By adopting a simple three-electrode structure, the size and manufacturing process of the sensor are fundamentally simplified, overcoming the problems of complex structure and high manufacturing cost of traditional sensors, and greatly improving the miniaturization and practicality of the sensor; through the multi-layer stacked structural design, the two modules have the ability to work independently or collaboratively without interfering with each other, simplifying the subsequent signal processing process and significantly improving the real-time response performance of the sensor; by using emerging highly conductive sensitive materials silver nanowires and carbon nanotubes as the main raw materials for the sensor's resistance sensitive layer, the flexibility of the sensor is guaranteed and the overall signal transmission efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the sensor in Example 1 of the present invention;

[0018] Figure 2 It is a structural schematic diagram of a resistor positioning unit of the present invention;

[0019] Figure 3 It is a schematic structural diagram of the piezoelectric unit of the present invention;

[0020] Figure 4 is the relationship between the stimulation position and the resistance value of the sensor in Example 2 of the present invention;

[0021] Figure 5 is the relationship between the stimulation position and the resistance value of the sensor in Example 3 of the present invention;

[0022] Figure 6 is the relationship between the force on the piezoelectric layer and the output voltage of the sensor in Example 2 of the present invention;

[0023] Figure 7 is the relationship between the force on the piezoelectric layer and the output voltage of the sensor in Example 3 of the present invention;

[0024] Among them, the numbers are: 1 is the insulating layer, 2 is the resistance sensitive layer, 3 is the gasket one, 4 is the middle electrode layer, 41 is the position where the wire is led out from the middle electrode layer, 5 is the piezoelectric layer, 6 is the packaging layer, 7 is the lower electrode layer, 71 is the position where the wire is led out from the lower electrode layer, 8 is the gasket two, 9 is the upper electrode, 91 is the position where the wire is led out from the upper electrode, and 10 is the cavity. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution, characteristics and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Embodiment 1 is a preferred embodiment of a three-electrode sensor integrating positioning and pressure detection in the present invention, such as Figure 1 shown.

[0027] It includes a resistor positioning unit, a gasket, a piezoelectric unit, and a packaging layer connected in sequence; wherein the resistor positioning unit is used to detect the position of the force; the upper parts of the two gaskets are respectively connected to the edge of the resistor positioning unit, and the lower parts of the two gaskets are respectively connected to the edge of the piezoelectric unit, so that the resistor positioning unit and the piezoelectric unit form a cavity structure; the piezoelectric unit is used to detect the magnitude of the force;

[0028] Furthermore, the resistance positioning unit is composed of an insulating layer, a resistance sensitive layer, and an upper electrode; the resistance sensitive layer is arranged on the lower surface of the insulating layer, and the upper electrode is arranged on the lower surface of the resistance sensitive layer; the piezoelectric unit is composed of a middle electrode layer, a piezoelectric layer, and a lower electrode layer connected in sequence; the upper electrode, the middle electrode layer, and the lower electrode layer are used to collect the voltage signal of the sensor.

[0029] Embodiment 2 is a preferred embodiment of a method for manufacturing a three-electrode sensor integrating positioning and pressure detection in the present invention; it comprises the following steps:

[0030] S1. Clean the film and cut the film to obtain an insulating layer and a packaging layer.

[0031] Specifically, the film is made of PET film; PET film has extremely high electrical insulation, can effectively isolate electrical signals, prevent current leakage or interference, and has a high cost performance.

[0032] Furthermore, the cut PET film has a length of 64 mm, a width of 9 mm, and a thickness of 0.2 mm.

[0033] S2. Clean the surface stains of the insulation layer and the packaging layer.

[0034] S3, coating the conductive mixed sensitive material on the lower surface of the insulating layer to form a resistance sensitive layer, drying, and attaching electrodes on the resistance sensitive layer to obtain a resistance positioning unit.

[0035] Specifically, the resistance positioning unit is composed of an insulating layer, a resistance sensitive layer, and an upper electrode; the resistance sensitive layer is arranged on the insulating layer, and the upper electrode is arranged on the resistance sensitive layer; the conductive mixed sensitive material is a mixture of a conductive material and a thickener; the conductive material is a dispersion of carbon nanotubes (CNTs) and silver nanowires (AgNWs); the thickener is methyl cellulose (MC); CNTs and AgNWs nanowires are dispersed, which have high strength and flexibility, and the conductivity is close to the metal level. If the conductive material is too little, it will cause the resistance sensitive layer surface to be difficult to form a path and uneven distribution, which will lead to reduced sensor sensitivity, linearity, service life, etc.

[0036] Furthermore, 8 ml (13 wt%) of carbon nanotube dispersion, 3 ml (10 mg / ml) of silver nanowires, and 0.01 g of methyl cellulose were mixed and stirred for 20 minutes; the resistive sensitive layer used the uniform insulating layer 1 of the material as the base, and the above-mentioned mixed material was evenly coated upward, coated once, and dried in a drying oven at 50°C. The upper electrode 9 used a copper foil with a thickness of 0.02 mm, a length of 1 mm, and a width of 9 mm. The effective length of the resistive sensitive layer is 60 mm, the width is 5 mm, the thickness is 0.2 mm, and the total resistance is 198 Ω. The relationship between the output resistance and the pressing position is as follows: Figure 4 shown.

[0037] S4, preparing a piezoelectric material solution, polarizing the piezoelectric material solution and pouring it into a mold, drying and demoulding it to obtain a piezoelectric layer.

[0038] Furthermore, the piezoelectric material solution is formed by mixing a polymer piezoelectric material with a solvent; this embodiment uses polyvinylidene fluoride (PVDF) as the piezoelectric material, and a mixed solution of acetone and N,N-dimethylformamide is selected as the solvent. PVDF has good flexibility and processing performance, and can be prepared into piezoelectric layers of varying thicknesses. The presence of fluorine atoms in its molecular chain structure makes it highly stable and fatigue-resistant. When pressed or bent, the upper and lower electrode surfaces of the piezoelectric material will generate electrical signals, the size of which is proportional to its deformation.

[0039] Specifically, 1.8g of polyvinylidene fluoride was added to 6ml of acetone and 9ml of N,N-dimethylformamide mixed solvent, and 0.3g of PVP (K40) was added; the thermal polarization method was used, and magnetic stirring was carried out at 70°C for 15 minutes. When the solution became a transparent gel, it was poured into a mold and naturally evaporated to form. The obtained piezoelectric layer was 60mm long, 5mm wide, and 1mm thick. The relationship between the output voltage of the piezoelectric layer and the force is as follows: Figure 6 shown.

[0040] S5. Attach a layer of metal electrode to each of the two surfaces of the piezoelectric layer to obtain a piezoelectric unit.

[0041] Specifically, the piezoelectric unit is composed of a middle electrode layer 4, a piezoelectric layer 5, and a lower electrode layer 7 connected in sequence. The middle electrode layer 4 is connected to the resistance sensitive layer through a cavity. The middle electrode layer 4 and the lower electrode layer 7 are both made of copper foil with a thickness of 0.02 mm. The middle electrode layer 4 is laid flat on the upper surface of the piezoelectric layer 5, and the lower electrode layer 7 is attached to the upper surface of the packaging layer 6. The middle electrode layer 4 and the lower electrode layer 7 are equal in width to the piezoelectric layer 5, and their length is equal to the length L+2 mm of the piezoelectric layer 5, so as to facilitate the connection of the wires. The structure of the piezoelectric unit is as follows: Figure 3 shown.

[0042] S6. Assemble the components from top to bottom in the order of resistor positioning unit, gasket, piezoelectric unit, and packaging layer; during the assembly process, two gaskets are used to fix the resistor positioning unit and the piezoelectric unit so that the two units do not contact each other when not working, and the non-contact parts form a cavity.

[0043] Specifically, the gasket is a rectangular polytetrafluoroethylene plate, the gasket 3 is 2 mm long, 9 mm wide, and 2 mm thick, and the gasket 8 is 2 mm long, 9 mm wide, and 1.78 mm thick. Figure 2 shown.

[0044] Furthermore, in this embodiment, the sensor is 64 mm long, 9 mm wide and 3.44 mm thick. The insulating layer 1 of the sensor is deformed under stress, so that the resistance sensitive layer 2 contacts the middle electrode layer 4. The upper electrode 9-resistance sensitive layer 2-middle electrode layer 4 forms a path to detect the resistance value of the resistance sensitive layer 2, and then determine the position information of the stress point. The upper electrode 9 and the middle electrode layer 4 realize the collection of resistance signals, and the middle electrode layer 4 and the lower electrode layer 7 realize the collection of voltage signals. The middle electrode layer 4 is the common working electrode of the resistance positioning unit and the piezoelectric unit. The upper electrode 9 and the lower electrode layer 7 are independently connected to the two units, so as to realize the detection of the spatial position and pressure information of the external stimulus.

[0045] Furthermore, conductive silver paste is used to connect wires to the upper electrode 9, the middle electrode layer 4, and the lower electrode layer 7. The wires of the upper electrode 9 and the middle electrode layer 4 are led out from 91 and 41, and the wire of the lower electrode layer 7 is led out from 71.

[0046] Embodiment 3 is another preferred embodiment of a method for manufacturing a three-electrode sensor integrating positioning and pressure detection.

[0047] The difference between Example 3 and Example 2 is that:

[0048] The proportion of conductive mixed sensitive materials is different. 8ml (13wt%) of carbon nanotube dispersion, 1ml (10mg / ml) of silver nanowires, and 0.01g of methyl cellulose are mixed and stirred for 20min. The total resistance of the resistive sensitive layer is 245Ω. The relationship between the output resistance and the pressing position is shown in Figure 5 shown.

[0049] The polymer piezoelectric material is polyvinylidene fluoride, and the solvent is a mixed solution of acetone and N,N-dimethylformamide; specifically, 1.7g of polyvinylidene fluoride is added to 6ml of acetone and 9ml of a mixed solvent of N,N-dimethylformamide, and 0.8g of PVP (K40) is added. The mixture is magnetically stirred at 70°C for 20min, and the solution is poured into a mold after it becomes a transparent gel. The solution is naturally evaporated to form a piezoelectric layer with a length of 60mm, a width of 5mm, and a thickness of 1mm. The relationship between the output voltage of the piezoelectric layer and the force is as follows: Figure 7 shown.

[0050] Finally, it should be noted that the above only describes some embodiments of the present invention. For those skilled in the art, it is conceivable that various changes, modifications, substitutions and deformations may be made to these embodiments without departing from the principles and spirit of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents, and the above-mentioned actions should be covered within the scope of protection of the present invention.

Claims

1. A three-electrode sensor integrating positioning and pressure detection, characterized in that: It includes a resistor positioning unit, a gasket, a piezoelectric unit, and a packaging layer connected in sequence; wherein the resistor positioning unit is used to detect the position of the force; the upper parts of the two gaskets are respectively connected to the edges of the resistor positioning unit, and the lower parts of the two gaskets are respectively connected to the edges of the piezoelectric unit, so that the resistor positioning unit and the piezoelectric unit form a cavity structure; the piezoelectric unit is used to detect the magnitude of the force.

2. The three-electrode sensor for integrated positioning and pressure detection according to claim 1, characterized in that: The resistance positioning unit is composed of an insulating layer, a resistance sensitive layer, and an upper electrode; the resistance sensitive layer is arranged on the lower surface of the insulating layer, and the upper electrode is arranged on the lower surface of the resistance sensitive layer; the piezoelectric unit is composed of a middle electrode layer, a piezoelectric layer, and a lower electrode layer connected in sequence; the upper electrode, the middle electrode layer, and the lower electrode layer are used to collect the voltage signal of the sensor.

3. A method for manufacturing a three-electrode sensor for integrated positioning and pressure detection, the method being used to manufacture the three-electrode sensor for integrated positioning and pressure detection state recognition as claimed in any one of claims 1 to 2, characterized in that: Includes steps: S1, cleaning the film and cutting the film to obtain an insulating layer and a packaging layer; S2. Clean the surface stains of the insulation layer and the packaging layer; S3, coating the conductive mixed sensitive material on the lower surface of the insulating layer to form a resistance sensitive layer, drying, and attaching electrodes on the resistance sensitive layer to obtain a resistance positioning unit; S4, preparing a piezoelectric material solution, polarizing the piezoelectric material solution and pouring it into a mold, drying and demoulding, to obtain a piezoelectric layer; S5, attaching a layer of metal electrodes to each of the two surfaces of the piezoelectric layer to obtain a piezoelectric unit; S6. Assemble the components from top to bottom in the order of resistor positioning unit, gasket, piezoelectric unit, and packaging layer; during the assembly process, two gaskets are used to fix the resistor positioning unit and the piezoelectric unit so that the two units do not contact each other when not working, and the non-contact parts form a cavity.

4. The manufacturing method of the three-electrode sensor integrating positioning and pressure detection according to claim 3, characterized in that: The film is an insulating film with a thickness of 0.2 mm, and the size of the insulating layer and the packaging layer are both 64 mm*9 mm.

5. The method for manufacturing a three-electrode sensor integrating positioning and pressure detection according to claim 3, characterized in that: The method used for polarizing the piezoelectric material solution is one or more of the following: thermal polarization method, electric field polarization method, mechanical stress polarization method, piezoelectric thin film material polarization method, and optical polarization method.

6. The method for manufacturing a three-electrode sensor integrating positioning and pressure detection according to claim 3, characterized in that: The thickness of the conductive mixed sensitive material is 0.2mm~1mm, and the conductivity range is 0.8×10 2 S / m~3.0×10 2 S / m.

7. The method for manufacturing a three-electrode sensor integrating positioning and pressure detection according to claim 6, characterized in that: The thickness of the piezoelectric layer is 0.5 mm to 2 mm, and the ratio of the thickness of the gasket to the thickness of the demoulded piezoelectric material is 0.5 to 2.

8. The method for manufacturing a three-electrode sensor integrating positioning and pressure detection according to claim 6, characterized in that: The temperature used for drying is 50°C to 60°C, and the temperature used for heating the piezoelectric material solution is 70°C.

9. The method for manufacturing a three-electrode sensor integrating positioning and pressure detection according to claim 6, characterized in that: The conductive mixed sensitive material is formed by mixing a conductive material and a thickener, the piezoelectric material solution is formed by mixing a polymer piezoelectric material and a solvent, and the volume fraction of the polymer piezoelectric material in the piezoelectric material solution is 6% to 8%.

10. The method for manufacturing a three-electrode sensor integrating positioning and pressure detection according to claim 9, characterized in that: The film is one of polyimide, epoxy resin, polytetrafluoroethylene, polyvinyl chloride, polyethylene terephthalate, and silicon oxide; The gasket is a rubber material such as chloroprene rubber, nitrile rubber, silicone, and a plastic and polymer material such as polytetrafluoroethylene and polyethylene; the conductive material is one or more of carbon nanotubes, metal nanowires, MXene, and graphene; the thickener is one or more of methyl cellulose, hydroxyethyl cellulose, sodium alginate, and sodium polyacrylate; the polymer piezoelectric material is one or more of polyvinylidene fluoride, polyvinyl fluoride, and polylactic acid; the solvent is one or more of N,N-dimethylformamide, acetone, N,N-dimethylacetamide, and cyclohexanone.

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