A pressure sensor based on friction nanogenerator

Abstract

The application discloses a pressure sensor based on friction nanogenerator, which can be deployed in a wearable device for monitoring pulse fluctuation, or deployed in an electronic device with a touch screen for detecting touch action. The sensor comprises two friction layers and at least one electrode layer. The two friction layers are respectively made of materials with different electron loss and gain abilities. The surface of at least one friction layer comprises a multi-stage micro-nano structure for inducing equal and opposite net charges corresponding to the applied pressure on the two friction layers under pressure. The multi-stage micro-nano structure comprises at least two kinds of micro-nano columnar structures with different heights. The electrode layer is used for generating current based on the net charges. The application can make the pressure sensor maintain high sensitivity to large static force through the designed multi-stage structure with different heights, and can expand the measurement range of the pressure sensor, so that the sensor maintains the same or similar sensitivity under various static forces.

Description

Technical Field

[0001] This application relates to the field of sensors, and more particularly to a pressure sensor based on triboelectric nanogenerators. Background Technology

[0002] In recent years, the demand for health monitoring has spurred the rapid development of wearable devices. For wearable devices, the core of accurate monitoring lies in sensor design. Accurately acquiring an individual's physiological signals using sensors is fundamental to accurately predicting diseases and providing valuable reference information for personal health management. Currently, significant progress has been made in the research of flexible sensors with different mechanisms both domestically and internationally, mainly including piezoelectric sensors, piezoresistive sensors, piezoresistive sensors, and triboelectric sensors based on electrostatic induction and charge transfer principles. The working principle of these flexible pressure sensors is to convert the external pressure signal applied to the sensor into an electrical signal output, thereby providing feedback on the magnitude and distribution of the external pressure.

[0003] Current pressure sensors utilize principles based on resistive, capacitive, piezoelectric, and triboelectric nanogenerator (TENG) technologies. Among these, TENG-based pressure sensors have garnered significant attention due to their advantages over other types, including a wider range of selectable materials, better dynamic response, faster response time, and richer detail in the measured physiological signals. TENG-based pressure sensors leverage the principles of triboelectricity and electrostatic induction. Triboelectricity occurs when materials with different electron-gathering and losing capacities come into contact; due to the varying binding abilities of the materials, electrons transfer, resulting in equal but opposite net charges on both materials. Electrostatic induction occurs when a charged object approaches a conductive object; the conductive object induces a charge opposite to the charged object's charge on the side closest to the charged object. TENG-based pressure sensors combine these two principles, such as… Figure 1 As shown, a TENG-based pressure sensor generally consists of two components: two electrode layers and two friction layers. The two friction layers are placed in the middle, and the two electrode layers are placed on both sides. When the two friction layers made of different materials come into contact with each other under the action of an external force, equal and opposite net charges are induced in the two friction layers due to the principle of triboelectric charging. When the contact surfaces of the two friction layers separate under the action of an external force, the potential difference generated by the separation of the two net charges drives electrons to flow between the electrodes attached to the upper and lower surfaces of the two friction layer materials, thereby generating a current output. Finally, the applied pressure is calculated by measuring the external current and voltage.

[0004] In the above-mentioned TENG-based pressure sensor, in order to increase the surface area during friction, improve the amount of charge transfer, and ultimately achieve the purpose of improving the output of voltage or current, the surface of one of the friction layers is generally modified, such as Figure 2 Figure 2 The test results of scanning electron microscope (SEM) test on the surface of one of the friction layers are shown in the figures. The modified micro-nano structures are consistent in height (i.e. Figure 2 hexagonal structures), and the overall height is not high, i.e. the overall surface is relatively flat, thus there are two problems: 1. the sensitivity to large static force is not enough, because when the external applied pressure is large, the two friction layers are completely in contact; 2. under the premise of ensuring sensitivity, the measurable pressure range is small, i.e. when the sensitivity is high under large static force, the sensitivity is low under small static force, and vice versa. SUMMARY

[0005] The embodiments of the present application provide a friction nano-generator-based pressure sensor. The surface of at least one friction layer of the TENG-based pressure sensor comprises a multi-stage micro-nano structure (i.e. a columnar structure comprising at least two different heights of micro-nano structures). By designing the multi-stage structure with different heights, the pressure sensor can maintain high sensitivity to large static force, and the measurement range of the pressure sensor can be expanded, so that the sensor maintains the same or similar sensitivity under various static forces.

[0006] Based on this, the embodiments of the present application provide the following technical solutions:

[0007] ​In a first aspect, the embodiments of the present application first provide a TENG-based pressure sensor, which can be used in the field of sensors. The TENG-based sensor includes two friction layers (a first friction layer and a second friction layer) and an electrode layer (which can be referred to as a first electrode layer). In the embodiments of the present application, an electrode line with a conductive effect is also considered as an electrode layer, which will not be explained below. The first friction layer and the second friction layer are made of materials with different electron loss and gain abilities. For example, the materials of the friction layers can be polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polyethylene (PE), polydimethylsiloxane (PDMS), fluorinated ethylene propylene (FEP), etc. It should be noted that the materials of the first friction layer and the second friction layer should be different. The first electrode layer is made of a material with a conductive ability, for example, a metal material (gold, silver, copper, etc.), a conductive material (graphene, indium tin oxides (ITO), silver nanowire, etc.), or the like. The first friction layer is connected to the first electrode layer. At least one of the surfaces of the first friction layer and the second friction layer has at least two different height micro-nano columnar structures (which can also be referred to as multi-stage micro-nano structures), which are used to induce an equal and opposite net charge corresponding to the applied pressure on the first friction layer and the second friction layer under pressure, and also provide a supporting effect. The first electrode layer is used to generate an electric current based on the equal and opposite net charge induced on the two friction layers. Finally, the applied pressure value can be inversely deduced through the conversion of the electric current and the applied pressure. It should be noted that in some application scenarios of the present application, the friction layer can also be used as an electrode layer with a conductive effect, which is not limited in the present application.

[0008] In the above-mentioned embodiments of the present application, the surface of at least one friction layer of the TENG-based pressure sensor includes multi-stage micro-nano structures (i.e., at least two different height micro-nano columnar structures). Through the design of the multi-stage structure with different heights, the pressure sensor can maintain high sensitivity to large static forces, and the measurement range of the pressure sensor can be expanded, so that the sensor maintains the same or similar sensitivity under various static forces.

[0009] In a possible implementation manner of the first aspect, the pressure sensor can further include an electrode layer, which can be referred to as a second electrode layer, the second electrode layer is also made of a material with electric conductivity, and the second friction layer is connected to the second electrode layer. In this case, the first electrode layer and the second electrode layer are used to generate an electric current based on the equal and opposite net charges induced on the first friction layer and the second friction layer corresponding to the pressure.

[0010] In the above-mentioned embodiments of the present application, it is specified that when the first electrode layer is not grounded, the pressure sensor further includes a second electrode layer for generating an electric current, which is feasible.

[0011] In a possible implementation manner of the first aspect, the micro-nano columnar structure can be made of only one material, or can be made of at least two materials with different Young's moduli, which is not limited by the present application.

[0012] In the above-mentioned embodiments of the present application, it is specified that the material constituting the micro-nano columnar structure can be one material or multiple materials (with different Young's moduli), which is optional.

[0013] In a possible implementation manner of the first aspect, when the micro-nano columnar structure is made of at least two materials with different Young's moduli, in this case, the micro-nano columnar structure is obtained by stacking at least two micro-nano sub-columnar structures, one sub-columnar structure corresponds to one material with a certain Young's modulus. For example, assuming that a micro-nano columnar structure is made of four materials with different Young's moduli, each material corresponds to a sub-columnar structure, and there are four sub-columnar structures in total, wherein the height of each sub-columnar structure can be the same or different, which is not limited here. Then, the four sub-columnar structures are stacked to form the micro-nano columnar structure.

[0014] In the above-mentioned embodiments of the present application, it is specified that when the micro-nano columnar structure is made of at least two materials with different Young's moduli, how the micro-nano columnar structure is formed, which is feasible.

[0015] In a possible implementation manner of the first aspect, the at least two micro-nano sub-columnar structures include but are not limited to: 1) the at least two micro-nano sub-columnar structures have the same cross-sectional area, as an example, assuming that there are four sub-columnar structures, the four sub-columnar structures have the same cross-sectional area in a top view of the pressure sensor; 2) the at least two micro-nano sub-columnar structures have different cross-sectional areas, in this case, the at least two micro-nano sub-columnar structures are stacked in order from large to small according to the cross-sectional area, as an example, assuming that there are four sub-columnar structures S1, S2, S3 and S4, and S1 < S2 < S3 < S4, then the stacking manner on the at least one friction layer is: D is located on the surface of the at least one friction layer, C is stacked on D, B is stacked on C, and A is stacked on B.

[0016] In the above-mentioned embodiments of the present application, several implementation manners of stacking the at least two micro-nano sub-columnar structures are specifically described, which are flexible.

[0017] In a possible implementation manner of the first aspect, the at least one friction layer can further grow some target micro-nano structures with a preset height, which can be referred to as a first preset height h1, to provide support under an external applied pressure, so as to avoid the first friction layer and the second friction layer from being directly attached together under the pressure. It should be noted that, in the embodiments of the present application, the first preset height h1 is greater than the height of any one of the at least two micro-nano columnar structures with different heights.

[0018] In the above-mentioned embodiments of the present application, when the external applied pressure is relatively large in actual application, the first friction layer and the second friction layer can be completely attached together, which can cause failure of the pressure sensor, reduce the sensitivity of the pressure sensor, and reduce the pressure measurement range of the pressure sensor. To reduce the probability of this situation, the at least one friction layer can further grow some target micro-nano structures with a preset height, so as to improve the pressure measurement range.

[0019] In a possible implementation manner of the first aspect, in addition to the first friction layer, the second friction layer, the first electrode layer, and the second electrode layer described above, the TENG-based pressure sensor further includes a separation layer with a preset height between the first friction layer and the second friction layer, which can be referred to as a second preset height h2, and the second preset height h2 is greater than the height of any one of the at least two micro-nano column structures with different heights. The separation layer has at least one hole with a preset aperture, and the separation layer is used to provide a supporting effect under an external applied pressure to avoid the first friction layer and the second friction layer directly adhering under the pressure. In this case, the multi-stage micro-nano structure is grown in the hole of the separation layer.

[0020] In the above embodiments of the present application, the way to provide the supporting effect is to additionally add a separation layer between the two friction layers, and the multi-stage micro-nano structure is grown in the hole of the separation layer. By using the separation layer and the multi-stage structure design, the problem of inconsistent sensor measurement caused by sag of the pressure sensor is reduced, and the sensor can be expressed in a linear interval by designing the height, area of the multi-stage structure, and the height, aperture size, and shape of the separation layer, and the sensitivity remains the same or close under various static force conditions.

[0021] In a possible implementation manner of the first aspect, the shape of the at least one hole on the separation layer can be any processable shape, for example, can be circular, can be elliptical, can be polygonal, further can be a regular polygon such as an equilateral triangle, a square, a hexagon, etc., or can be an irregular polygon such as a trapezoid, an unequal triangle, etc., and the present application does not limit the shape of the hole of the separation layer. In addition, not only the shape of the hole can be set according to requirements, but also the opening area of the hole can be set, and the present application does not limit this.

[0022] In the above embodiments of the present application, it is specifically stated that the shape of the hole of the separation layer can be set according to requirements, which is flexible.

[0023] In a possible implementation manner of the first aspect, the shape of the micro-nano column structure can be any processable shape with a certain height, for example, can be any one or more of a cylindrical shape, a polygonal prism shape, a conical shape, a polygonal pyramid shape, a hemispherical shape, an inverted pyramid shape, and a pyramid shape.

[0024] In the above embodiments of the present application, it is specifically stated that the shape of the micro-nano column structure can also be processed according to requirements, which is selectable.

[0025] In a possible implementation manner of the first aspect, the micro-nano column structures of different heights can be arranged periodically or irregularly, which is not limited in the application.

[0026] In the above-mentioned embodiments of the application, several arrangement manners of the micro-nano column structures of different heights are specifically described, which are flexible.

[0027] In a possible implementation manner of the first aspect, the multi-level micro-nano structure can be regarded as a first-level micro-nano structure, and micro-nano processing can be further performed on the multi-level micro-nano structure (that is, on each micro-nano column structure) to increase the friction area between the first friction layer and the second friction layer. Specifically, a micro-nano level burr structure can be etched on the multi-level micro-nano structure by using an etching process, which can also be referred to as a second-level micro-nano structure. The burr structure can be used to increase the charge amount of the net charge induced on the first friction layer and the second friction layer under the action of the applied pressure.

[0028] In the above-mentioned embodiments of the application, the burr structure is etched on each micro-nano column structure to increase the friction area of the first friction layer and the second friction layer, so as to increase the charge amount of the net charge induced on the two friction layers, thereby improving the detection sensitivity of the pressure sensor.

[0029] In a possible implementation manner of the first aspect, the TENG-based pressure sensor can be deployed in a wearable device to monitor pulse fluctuations, and the detection sensitivity can be effectively improved.

[0030] In the above-mentioned embodiments of the application, an application scenario of the TENG-based pressure sensor provided in the embodiments of the application is described, which is feasible.

[0031] In a possible implementation manner of the first aspect, the TENG-based pressure sensor can be deployed in an electronic device with a touch screen to detect touch actions, and the detection sensitivity can be effectively improved.

[0032] In the above-mentioned embodiments of the application, another application scenario of the TENG-based pressure sensor provided in the embodiments of the application is described, which is feasible.

[0033] The second aspect of the embodiment of the present application provides a pressure sensor based on TENG, which can be used in the field of sensors. The TENG-based sensor includes two friction layers (a first friction layer and a second friction layer) and an electrode layer (which can be referred to as a first electrode layer). In the embodiment of the present application, the electrode line with the conductive effect is also considered as the electrode layer, which will not be explained below. The first friction layer and the second friction layer are made of materials with different electron loss and gain abilities. For example, the material of the friction layer can be selected from PTFE, PET, PE, PDMS, FEP and the like. It should be noted that the materials of the first friction layer and the second friction layer should be different. The first electrode layer is made of a material with conductive ability, for example, a metal material (gold, silver, copper and the like), a conductive material (graphene, indium tin oxides (ITO), silver nanowire and the like) and the like. The first friction layer is connected to the first electrode layer. At least one micro-nano columnar structure is grown on the surface of at least one of the first friction layer and the second friction layer, which is used to induce an equal and opposite net charge corresponding to the pressure on the first friction layer and the second friction layer under pressure. The micro-nano columnar structure is made of at least two materials with different Young's moduli. The first electrode layer is used to generate current based on the equal and opposite net charge induced on the two friction layers. Finally, the applied pressure value can be deduced by converting the current and the applied pressure. It should be noted that in some application scenarios of the present application, the friction layer can also be used as an electrode layer with conductive effect, which is not limited in the present application.

[0034] In a possible implementation manner of the second aspect, the pressure sensor can further include an electrode layer, which can be referred to as a second electrode layer. The second electrode layer is also made of a material with conductive ability, and the second friction layer is connected to the second electrode layer. In this case, the first electrode layer and the second electrode layer are used to generate current based on the equal and opposite net charge corresponding to the pressure induced on the first friction layer and the second friction layer.

[0035] In the above-mentioned implementation manner of the present application, it is explained that when the first electrode layer is not grounded, the pressure sensor further includes a second electrode layer for generating current, which has realizability.

[0036] In a possible implementation manner of the second aspect, the micro-nano columnar structure is obtained by stacking at least two micro-nano sub-columnar structures, and one sub-columnar structure corresponds to one material with a Young's modulus. For example, assuming that the micro-nano columnar structure is made of four materials with different Young's moduli, each material corresponds to one sub-columnar structure, and there are four sub-columnar structures in total. The height of each sub-columnar structure can be the same or different, which is not limited herein. Then, the four sub-columnar structures are stacked to form the micro-nano columnar structure.

[0037] In the above-mentioned embodiments of the present application, it is specified how the micro-nano columnar structure is formed when the micro-nano columnar structure is made of at least two materials with different Young's moduli, and the micro-nano columnar structure is realizable.

[0038] In a possible implementation manner of the second aspect, the at least two micro-nano sub-columnar structures include but are not limited to: 1) the cross-sectional areas of the at least two micro-nano sub-columnar structures are the same. For example, assuming that there are four sub-columnar structures, the cross-sectional areas of the four sub-columnar structures are the same from the perspective of the top view of the pressure sensor; 2) the cross-sectional areas of the at least two micro-nano sub-columnar structures are different. In this case, the at least two micro-nano sub-columnar structures are stacked in the order from large to small according to the values of the cross-sectional areas. For example, assuming that there are four sub-columnar structures S1, S2, S3 and S4, and S1 < S2 < S3 < S4, the stacking manner on the at least one friction layer is: D is located on the surface of the at least one friction layer, C is stacked on D, B is stacked on C, and A is stacked on B.

[0039] In the above-mentioned embodiments of the present application, it is specified that the at least two micro-nano sub-columnar structures are stacked in several implementation manners, and the at least two micro-nano sub-columnar structures are flexible.

[0040] In a possible implementation manner of the second aspect, the micro-nano columnar structures generated on the at least one friction layer can be multiple, and the heights of the multiple micro-nano columnar structures can be the same or at least two different heights. The heights of the micro-nano columnar structures are not limited herein. For example, there are 100 micro-nano columnar structures, and the heights of the 100 micro-nano columnar structures can be the same, all being h0. Alternatively, the heights of the 100 micro-nano columnar structures can be n different heights, n≥2, for example, the heights of 50 micro-nano columnar structures are H1, and the heights of the remaining 50 micro-nano columnar structures are H2.

[0041] In the above-mentioned embodiments of the present application, it is specified that the heights of the micro-nano columnar structures generated on the at least one friction layer can be the same or different, and the heights of the micro-nano columnar structures can be designed according to the required pressure range and sensitivity requirement, and the heights of the micro-nano columnar structures are flexible.

[0042] In a possible implementation manner of the second aspect, the micro-nano column structures with different heights can be arranged periodically or irregularly.

[0043] In the above-described embodiments of the present application, several arrangement manners of the micro-nano column structures with different heights are specifically described, which are flexible.

[0044] In a possible implementation manner of the second aspect, some target micro-nano structures with a preset height can also be grown on at least one of the first friction layer and the second friction layer, which can be referred to as a first preset height h1, and the target micro-nano structures are used to provide a supporting action under an external applied pressure, so as to avoid the first friction layer and the second friction layer from being directly attached together under the pressure. It should be noted that, in the embodiments of the present application, the first preset height h1 is greater than the height of any one of the at least two micro-nano column structures with different heights.

[0045] In the above-described embodiments of the present application, when the external applied pressure is relatively large in actual application, the first friction layer and the second friction layer can be completely attached together, which can cause failure of the pressure sensor, reduce sensitivity of the pressure sensor, and reduce a pressure measurement range of the pressure sensor. To reduce the probability of the above-mentioned situation, some target micro-nano structures with a preset height can also be grown on at least one of the first friction layer and the second friction layer, so as to improve the pressure measurement range.

[0046] In a possible implementation manner of the second aspect, in addition to the first friction layer, the second friction layer, the first electrode layer, and the second electrode layer described above, the TENG-based pressure sensor further includes a preset height isolation layer between the first friction layer and the second friction layer, which can be referred to as a second preset height h2, and the second preset height h2 is greater than the height of any one of the at least two micro-nano column structures with different heights. The isolation layer has at least one hole with a preset aperture, and the isolation layer is used to provide a supporting action under an external applied pressure, so as to avoid the first friction layer and the second friction layer from being directly attached together under the pressure. In this case, the multi-stage micro-nano structure is grown in the hole of the isolation layer.

[0047] In the above embodiments of this application, the support is provided by adding an additional isolation layer between the two friction layers. The multi-level micro-nano structure is grown in the pores of the isolation layer. By adopting the isolation layer and multi-level structure design, the problem of inconsistent sensor measurement caused by the sag of the pressure sensor is reduced. Furthermore, by designing the height and area of ​​the multi-level structure, as well as the height, aperture size, and shape of the isolation layer, the sensor can be made to express within the linearity range and maintain the same or similar sensitivity under various static force conditions.

[0048] In one possible implementation of the second aspect, the shape of at least one hole on the isolation layer can be any manufacturable shape, such as a circle, an ellipse, or a polygon. Further, it can be a regular polygon, such as an equilateral triangle, a square, or a hexagon, or an irregular polygon, such as a trapezoid or a scalene triangle. Specifically, this application does not limit the shape of the hole in the isolation layer. Furthermore, not only can the shape of the hole be set according to requirements, but the opening area of ​​the hole can also be set independently; this application does not limit this aspect.

[0049] In the above embodiments of this application, it is specifically described that the shape of the holes in the isolation layer can be set according to needs, which is flexible.

[0050] In one possible implementation of the second aspect, the shape of the micro / nano columnar structure can be any workable shape with a certain height, for example, it can be any one or more of the following: cylindrical, polygonal prism, conical, polygonal pyramidal, hemispherical, inverted pyramidal, and pyramidal.

[0051] In the above embodiments of this application, it is specifically illustrated that the shape of the micro-nano columnar structure can also be processed according to requirements, and is selective.

[0052] In one possible implementation of the second aspect, in order to increase the friction area between the first friction layer and the second friction layer, micro-nano processing can also be performed on each micro-nano columnar structure. Specifically, micro-nano columnar structures can be etched with micro-nano-level burr structures, also known as secondary micro-nano structures, using an etching process. These burr structures can be used to increase the amount of net charge induced on the first friction layer and the second friction layer under the applied pressure.

[0053] In the above embodiments of this application, the friction area between the first friction layer and the second friction layer is increased by etching burr structures on each micro-nano columnar structure, thereby increasing the amount of net charge induced on the two friction layers and improving the detection sensitivity of the pressure sensor.

[0054] In one possible implementation of the second aspect, a TENG-based pressure sensor can be deployed in a wearable device to monitor pulse fluctuations, which can effectively improve detection sensitivity.

[0055] The above embodiments of this application illustrate an application scenario of the TENG-based pressure sensor provided in this application, which is feasible.

[0056] In one possible implementation of the second aspect, a TENG-based pressure sensor can be deployed on an electronic device with a touchscreen to detect touch actions, which can effectively improve detection sensitivity.

[0057] In the above embodiments of this application, another application scenario of the TENG-based pressure sensor provided by the embodiments of this application is described, which is feasible.

[0058] A third aspect of this application also provides a pressure sensor, which can be a piezoresistive pressure sensor, a piezoresistive pressure sensor, or a piezoelectric pressure sensor; the specific type is not limited in this application. The pressure sensor includes: a functional layer, a first electrode layer, and a second electrode layer. The first electrode layer and the second electrode layer are made of a conductive material. In this embodiment, conductive electrode wires are also considered electrode layers, and will not be explained further below. The functional layer is connected to one of the first or second electrode layers. The surface of the functional layer includes at least two different heights of micro / nano columnar structures for sensing a first signal corresponding to the pressure under pressure. The first electrode layer and the second electrode layer are used to generate a second signal based on the first signal.

[0059] In the above embodiments of this application, the multi-level micro-nano structure (i.e., at least two kinds of micro-nano columnar structures with different heights) can be applied not only to pressure sensors based on triboelectric nanogenerators, but also to pressure sensors of the piezoresistive, piezoresistive, and piezoelectric types, and has wide applicability.

[0060] In one possible implementation of the third aspect, when the first signal is a first resistor (i.e., the pressure sensor is a piezoresistive type), the second signal is a second resistor; or, when the first signal is a first capacitor (i.e., the pressure sensor is a piezoresistive type), the second signal is a second capacitor; or, when the first signal is a first voltage (i.e., the pressure sensor is a piezoelectric type), the second signal is a second voltage.

[0061] In the above embodiments of this application, it is specifically explained that the second signal to be output is different depending on the type of the first signal, which can be applied to various types of pressure sensors and has flexibility.

[0062] In one possible implementation of the third aspect, when the first signal is a first resistor (i.e., the pressure sensor is a piezoresistive type), the functional layer is made of a material that has resistive properties that change under different pressures (i.e., has resistive characteristics); or, when the first signal is a first capacitor (i.e., the pressure sensor is a piezoresistive type), the functional layer is made of a material that has capacitive properties that change under different pressures (i.e., has capacitive characteristics); or, when the first signal is a first voltage (i.e., the pressure sensor is a piezoelectric type), the functional layer is made of a material that has piezoelectric properties that change under different pressures (i.e., has piezoelectric characteristics).

[0063] In the above embodiments of this application, it is specifically explained that the material properties of the functional layer in different types of pressure sensors are different, which provides flexibility.

[0064] In one possible implementation of the third aspect, the functional layer may be one or two, and this application does not limit this.

[0065] In the above embodiments of this application, the number of functional layers is not limited to one or two, and can be selected based on actual application, thus having wide applicability.

[0066] In one possible implementation of the third aspect, a micro-nano columnar structure may be made of only one material or of at least two materials with different Young's moduli, and the application does not limit this.

[0067] In the above embodiments of this application, the materials constituting a micro-nano columnar structure are specifically described. They can be one material or multiple materials (with different Young's moduli), and are selectable.

[0068] In one possible implementation of the third aspect, the micro / nano columnar structure is formed by stacking at least two micro / nano sub-columnar structures, each of which is made of a material with a Young's modulus. That is, when the micro / nano columnar structure is made of at least two different materials with Young's moduli, it is formed by stacking at least two micro / nano sub-columnar structures, with each sub-columnar structure corresponding to a material with a Young's modulus. For example, assuming a micro / nano columnar structure is made of four different materials with Young's moduli, each material corresponds to one sub-columnar structure, resulting in four sub-columnar structures. The height of each sub-columnar structure can be the same or different; this is not limited here. These four sub-columnar structures are then stacked to form the micro / nano columnar structure.

[0069] In the above embodiments of this application, it is specifically explained how the micro-nano columnar structure is formed when it is made of materials with at least two different Young's moduli, and the feasibility of this is demonstrated.

[0070] In one possible implementation of the third aspect, the at least two micro-nano sub-column structures have the same cross-sectional area; or, the at least two micro-nano sub-column structures are stacked sequentially in descending order of cross-sectional area. That is, the at least two micro-nano sub-column structures include, but are not limited to: 1) the at least two micro-nano sub-column structures have the same cross-sectional area. As an example, suppose there are four sub-column structures, and from a top view of the pressure sensor, the cross-sectional areas of these four sub-column structures are the same; 2) the at least two micro-nano sub-column structures have different values ​​of cross-sectional area, in which case they are stacked sequentially in descending order of cross-sectional area.

[0071] In the above embodiments of this application, several implementation methods for stacking at least two micro-nano sub-pillar structures are specifically described, which have flexibility.

[0072] In one possible implementation of the third aspect, the functional layer further includes: a target micro / nano structure with a first preset height, wherein the first preset height is greater than the height of any one of the at least two different heights of the micro / nano columnar structures. That is, some target micro / nano structures with a preset height, referred to as the first preset height h1, can also be grown on the functional layer to provide support under external pressure, thereby preventing the two electrode layers from directly adhering under the pressure. It should be noted that, in this embodiment, the first preset height h1 is greater than the height of any one of the at least two different heights of the micro / nano columnar structures.

[0073] In the above embodiments of this application, in practical applications, when the external pressure is relatively large, the two electrode layers (assuming the electrode layers are not electrode wires) may completely adhere together. This can lead to the failure of the pressure sensor, reducing its sensitivity and narrowing its pressure measurement range. To reduce the probability of this happening, some target micro / nano structures of a predetermined height can be grown on the functional layer, thereby improving the pressure measurement range.

[0074] In one possible implementation of the third aspect, the sensor further includes: an isolation layer of a second preset height, the isolation layer having at least one pore of a preset aperture, the isolation layer being located on the functional layer, and the micro / nano columnar structures being deployed within the pores of the isolation layer, the second preset height being greater than the height of any one of the at least two different heights of the micro / nano columnar structures. That is, in addition to the functional layer, the first electrode layer, and the second electrode layer described above, the pressure sensor also includes an isolation layer of a preset height on the functional layer, which can be referred to as the second preset height h2, and the second preset height h2 is greater than the height of any one of the at least two different heights of the micro / nano columnar structures. The isolation layer has at least one pore of a preset aperture, and the isolation layer provides support under external pressure to prevent the two electrode layers (assuming the electrode layers are not electrode wires) from directly adhering under the pressure. In this case, the multi-level micro / nano structure grows within the pores of the isolation layer.

[0075] In the above embodiments of this application, the support is provided by adding an additional isolation layer on the functional layer, and the multi-level micro-nano structure is grown in the pores of the isolation layer. By adopting the isolation layer and multi-level structure design, the problem of inconsistent sensor measurement caused by the sag of the pressure sensor is reduced. Furthermore, by designing the height and area of ​​the multi-level structure, as well as the height, aperture size, and shape of the isolation layer, the sensor can be made to express within the linearity range and maintain the same or similar sensitivity under various static force conditions.

[0076] In one possible implementation of the third aspect, the shape of the at least one hole includes any one or more of the following: circular, elliptical, or polygonal. That is, the shape of the at least one hole on the isolation layer can be any manufacturable shape, for example, it can be circular, elliptical, or polygonal. Further, it can be a regular polygon, such as an equilateral triangle, square, or hexagon, or an irregular polygon, such as a trapezoid or scalene triangle. Specifically, this application does not limit the shape of the hole in the isolation layer. Furthermore, not only can the shape of the hole be set according to requirements, but the opening area of ​​the hole can also be set independently; this application does not limit this aspect.

[0077] In the above embodiments of this application, it is specifically described that the shape of the holes in the isolation layer can be set according to needs, which is flexible.

[0078] In one possible implementation of the third aspect, the shape of the micro-nano columnar structure can be any processable shape with a certain height. For example, the shape of the micro-nano columnar structure includes any one or more of the following: cylindrical, polygonal prism, conical, polygonal pyramid, hemispherical, inverted pyramid, and pyramidal.

[0079] In the above embodiments of this application, it is specifically illustrated that the shape of the micro-nano columnar structure can also be processed according to requirements, and is selective.

[0080] In one possible implementation of the third aspect, the micro- and nano-column structures of different heights can be arranged periodically or in an irregular, disordered manner; this application does not impose any specific limitations on this.

[0081] In the above embodiments of this application, several arrangements of micro- and nano-column structures of different heights are specifically described, which are flexible.

[0082] In one possible implementation of the third aspect, the multi-level micro-nano structure can be regarded as a first-level micro-nano structure. In order to increase the contact area of ​​the functional layer, micro-nano processing can also be performed on the multi-level micro-nano structure (i.e., on the columnar structure of each micro-nano). Specifically, micro-nano-level burr structures can be etched on the multi-level micro-nano structure using an etching process, which can also be called second-level micro-nano structures. The burr structures can be used to increase the intensity of the first signal induced on the functional layer under the action of applied pressure.

[0083] In the above embodiments of this application, by etching burr structures on each micro-nano columnar structure, the contact area between the functional layer and the outside world is increased, thereby increasing the intensity of the first signal sensed on the functional layer and improving the detection sensitivity of the pressure sensor.

[0084] In one possible implementation of the third aspect, the pressure sensor can be deployed in a wearable device to monitor pulse fluctuations, which can effectively improve detection sensitivity.

[0085] The above embodiments of this application illustrate an application scenario of the pressure sensor provided in the embodiments of this application, which is feasible.

[0086] In one possible implementation of the third aspect, the pressure sensor can be deployed on an electronic device with a touchscreen to detect touch actions, which can effectively improve detection sensitivity.

[0087] The above embodiments of this application illustrate another application scenario of the pressure sensor provided in this application, which is feasible.

[0088] A fourth aspect of this application also provides a pressure sensor, which can be a piezoresistive pressure sensor, a piezoresistive pressure sensor, or a piezoelectric pressure sensor; the specific type is not limited in this application. The pressure sensor includes: a functional layer, a first electrode layer, and a second electrode layer. The first electrode layer and the second electrode layer are made of a conductive material. In this embodiment, conductive electrode wires are also considered electrode layers, and will not be explained further below. The functional layer is connected to one of the first or second electrode layers. The surface of the functional layer includes micro / nano columnar structures for sensing a first signal corresponding to the pressure under pressure. The micro / nano columnar structures are made of at least two materials with different Young's moduli. The first electrode layer and the second electrode layer are used to generate a second signal based on the first signal.

[0089] In the above embodiments of this application, the multi-level micro-nano structure (i.e., at least two kinds of micro-nano columnar structures with different heights) can be applied not only to pressure sensors based on triboelectric nanogenerators, but also to pressure sensors of the piezoresistive, piezoresistive, and piezoelectric types, and has wide applicability.

[0090] In one possible implementation of the fourth aspect, when the first signal is a first resistor (i.e., the pressure sensor is a piezoresistive type), the second signal is a second resistor; or, when the first signal is a first capacitor (i.e., the pressure sensor is a piezoresistive type), the second signal is a second capacitor; or, when the first signal is a first voltage (i.e., the pressure sensor is a piezoelectric type), the second signal is a second voltage.

[0091] In the above embodiments of this application, it is specifically explained that the second signal to be output is different depending on the type of the first signal, which can be applied to various types of pressure sensors and has flexibility.

[0092] In one possible implementation of the fourth aspect, when the first signal is a first resistor (i.e., the pressure sensor is a piezoresistive type), the functional layer is made of a material that has resistive properties that change under different pressures (i.e., has resistive characteristics); or, when the first signal is a first capacitor (i.e., the pressure sensor is a piezoresistive type), the functional layer is made of a material that has capacitive properties that change under different pressures (i.e., has capacitive characteristics); or, when the first signal is a first voltage (i.e., the pressure sensor is a piezoelectric type), the functional layer is made of a material that has piezoelectric properties that change under different pressures (i.e., has piezoelectric characteristics).

[0093] In the above embodiments of this application, it is specifically explained that the material properties of the functional layer in different types of pressure sensors are different, which provides flexibility.

[0094] In one possible implementation of the fourth aspect, the functional layer may be one or two, and this application does not limit this.

[0095] In the above embodiments of this application, the number of functional layers is not limited to one or two, and can be selected based on actual application, thus having wide applicability.

[0096] In one possible implementation of the fourth aspect, the micro / nano columnar structure is formed by stacking at least two micro / nano sub-columnar structures, each sub-columnar structure corresponding to a material with a Young's modulus. For example, assuming a micro / nano columnar structure is made of four materials with different Young's moduli, each material corresponds to one sub-columnar structure, resulting in a total of four sub-columnar structures. The height of each sub-columnar structure can be the same or different, and this is not limited here. Then, these four sub-columnar structures are stacked to form the aforementioned micro / nano columnar structure.

[0097] In the above embodiments of this application, it is specifically explained how the micro-nano columnar structure is formed when it is made of materials with at least two different Young's moduli, and the feasibility of this is demonstrated.

[0098] In one possible implementation of the fourth aspect, the at least two micro-nano sub-column structures have the same cross-sectional area; or, the at least two micro-nano sub-column structures are stacked sequentially in descending order of cross-sectional area. That is, the at least two micro-nano sub-column structures include, but are not limited to: 1) the at least two micro-nano sub-column structures have the same cross-sectional area. As an example, suppose there are four sub-column structures, and from a top view of the pressure sensor, the cross-sectional areas of these four sub-column structures are the same; 2) the at least two micro-nano sub-column structures have different cross-sectional area values, in which case they are stacked sequentially in descending order of cross-sectional area value.

[0099] In the above embodiments of this application, several implementation methods for stacking at least two micro-nano sub-pillar structures are specifically described, which have flexibility.

[0100] In one possible implementation of the fourth aspect, the plurality of said micro / nano columnar structures have at least two different heights. That is, there can be multiple micro / nano columnar structures generated on the functional layer. These multiple micro / nano columnar structures can have the same height or at least two different heights; this application does not specifically limit this. For example, there are 100 micro / nano columnar structures. The height of these 100 micro / nano columnar structures can all be the same, h0; these 100 micro / nano columnar structures can also have n different heights, n≥2, such as 50 micro / nano columnar structures having a height of H1, and the remaining 50 micro / nano columnar structures having a height of H2.

[0101] In the above embodiments of this application, it is specifically explained that the height of the micro-nano columnar structures generated on the functional layer can be the same or different. The height of the micro-nano columnar structures can be designed based on the required pressure range and sensitivity requirements, which provides flexibility.

[0102] In one possible implementation of the fourth aspect, the micro- and nano-column structures of different heights can be arranged periodically or in an irregular, disordered order; this application does not impose any specific limitations on this.

[0103] In the above embodiments of this application, several arrangements of micro- and nano-column structures of different heights are specifically described, which are flexible.

[0104] In one possible implementation of the fourth aspect, the functional layer further includes: a target micro / nano structure with a first preset height, wherein the first preset height is greater than the height of any one of the at least two different heights of the micro / nano columnar structures. That is, some target micro / nano structures with a preset height, referred to as the first preset height h1, can also be grown on the functional layer to provide support under external pressure, thereby preventing the two electrode layers from directly adhering under the pressure. It should be noted that, in this embodiment, the first preset height h1 is greater than the height of any one of the at least two different heights of the micro / nano columnar structures.

[0105] In the above embodiments of this application, in practical applications, when the external pressure is relatively large, the two electrode layers (assuming the electrode layers are not electrode wires) may completely adhere together. This can lead to the failure of the pressure sensor, reducing its sensitivity and narrowing its pressure measurement range. To reduce the probability of this happening, some target micro / nano structures of a predetermined height can be grown on the functional layer, thereby improving the pressure measurement range.

[0106] In one possible implementation of the fourth aspect, the sensor further includes: an isolation layer of a second preset height, the isolation layer having at least one pore of a preset aperture, the isolation layer being located on the functional layer, and the micro / nano columnar structures being deployed within the pores of the isolation layer, the second preset height being greater than the height of any one of the at least two different heights of the micro / nano columnar structures. That is, in addition to the functional layer, the first electrode layer, and the second electrode layer described above, the pressure sensor also includes an isolation layer of a preset height on the functional layer, which can be referred to as the second preset height h2, and the second preset height h2 is greater than the height of any one of the at least two different heights of the micro / nano columnar structures. The isolation layer has at least one pore of a preset aperture, and the isolation layer provides support under external pressure to prevent the two electrode layers (assuming the electrode layers are not electrode wires) from directly adhering under the pressure. In this case, the multi-level micro / nano structure grows within the pores of the isolation layer.

[0107] In the above embodiments of this application, the support is provided by adding an additional isolation layer on the functional layer, and the multi-level micro-nano structure is grown in the pores of the isolation layer. By adopting the isolation layer and multi-level structure design, the problem of inconsistent sensor measurement caused by the sag of the pressure sensor is reduced. Furthermore, by designing the height and area of ​​the multi-level structure, as well as the height, aperture size, and shape of the isolation layer, the sensor can be made to express within the linearity range and maintain the same or similar sensitivity under various static force conditions.

[0108] In one possible implementation of the fourth aspect, the shape of the at least one hole includes any one or more of the following: circular, elliptical, or polygonal. That is, the shape of the at least one hole on the isolation layer can be any manufacturable shape, for example, it can be circular, elliptical, or polygonal. Further, it can be a regular polygon, such as an equilateral triangle, square, or hexagon, or an irregular polygon, such as a trapezoid or scalene triangle. Specifically, this application does not limit the shape of the hole in the isolation layer. Furthermore, not only can the shape of the hole be set according to requirements, but the opening area of ​​the hole can also be set independently; this application does not limit this aspect.

[0109] In the above embodiments of this application, it is specifically described that the shape of the holes in the isolation layer can be set according to needs, which is flexible.

[0110] In one possible implementation of the fourth aspect, the shape of the micro-nano columnar structure can be any processable shape with a certain height. For example, the shape of the micro-nano columnar structure includes any one or more of the following: cylindrical, polygonal prism, conical, polygonal pyramid, hemispherical, inverted pyramid, and pyramidal.

[0111] In the above embodiments of this application, it is specifically illustrated that the shape of the micro-nano columnar structure can also be processed according to requirements, and is selective.

[0112] In one possible implementation of the fourth aspect, the multi-level micro-nano structure can be regarded as a first-level micro-nano structure. In order to increase the contact area of ​​the functional layer, micro-nano processing can also be performed on the multi-level micro-nano structure (i.e., on the columnar structure of each micro-nano). Specifically, micro-nano-level burr structures can be etched on the multi-level micro-nano structure using an etching process, which can also be called second-level micro-nano structures. The burr structures can be used to increase the intensity of the first signal induced on the functional layer under the action of applied pressure.

[0113] In the above embodiments of this application, by etching burr structures on each micro-nano columnar structure, the contact area between the functional layer and the outside world is increased, thereby increasing the intensity of the first signal sensed on the functional layer and improving the detection sensitivity of the pressure sensor.

[0114] In one possible implementation of the fourth aspect, the pressure sensor can be deployed in a wearable device to monitor pulse fluctuations, which can effectively improve detection sensitivity.

[0115] The above embodiments of this application illustrate an application scenario of the pressure sensor provided in the embodiments of this application, which is feasible.

[0116] In one possible implementation of the fourth aspect, the pressure sensor can be deployed on an electronic device with a touchscreen to detect touch actions, which can effectively improve detection sensitivity.

[0117] The above embodiments of this application illustrate another application scenario of the pressure sensor provided in this application, which is feasible.

[0118] The fifth aspect of this application also provides an electronic device, which may include a pressure sensor of the first aspect or any possible implementation of the first aspect, or the electronic device may include a pressure sensor of the second aspect or any two possible implementations of the first aspect, or the electronic device may include a pressure sensor of the third aspect or any one possible implementation of the third aspect, or the electronic device may include a pressure sensor of the fourth aspect or any two possible implementations of the fourth aspect. Attached Figure Description

[0119] Figure 1 This is a schematic diagram of a TENG-based pressure sensor.

[0120] Figure 2 The image shows the test results obtained from SEM testing of the surface of a friction layer.

[0121] Figure 3 A schematic diagram of the structure of a TENG-based pressure sensor provided in an embodiment of this application;

[0122] Figure 4 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0123] Figure 5 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0124] Figure 6 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0125] Figure 7 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0126] Figure 8 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0127] Figure 9 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0128] Figure 10 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0129] Figure 11 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0130] Figure 12Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0131] Figure 13 A schematic diagram of a TENG-based pressure sensor with a target micro / nano structure having a first preset height, provided in an embodiment of this application;

[0132] Figure 14 A schematic diagram of the processing procedure for the friction layer provided in the embodiments of this application;

[0133] Figure 15 Another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application;

[0134] Figure 16 A schematic diagram of a pore in an isolation layer for the growth of a multi-level micro / nano structure provided in an embodiment of this application;

[0135] Figure 17 A schematic diagram of the hole shape provided in an embodiment of this application;

[0136] Figure 18 A schematic diagram illustrating the processing of the friction layer and the isolation layer provided in the embodiments of this application;

[0137] Figure 19 A schematic diagram of the structure of a pressure sensor provided in an embodiment of this application;

[0138] Figure 20 This is another structural schematic diagram of the pressure sensor provided in the embodiments of this application;

[0139] Figure 21 This is another structural schematic diagram of the pressure sensor provided in the embodiments of this application;

[0140] Figure 22 This is another structural schematic diagram of the pressure sensor provided in the embodiments of this application;

[0141] Figure 23 A schematic diagram of the structure of the functional layer provided in the embodiments of this application;

[0142] Figure 24 This is another structural diagram of the functional layer provided in an embodiment of this application. Detailed Implementation

[0143] This application provides a pressure sensor based on triboelectric nanogenerator. The surface of at least one friction layer of the pressure sensor includes a multi-level micro-nano structure (i.e., including at least two types of micro-nano columnar structures of different heights). By designing multi-level structures of different heights, the pressure sensor can maintain high sensitivity to large static forces and expand the measurement range of the pressure sensor, so that the sensor maintains the same or similar sensitivity under various static forces.

[0144] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0145] This application involves many aspects of sensor-related knowledge. To better understand the solutions in this application, the relevant terms and concepts that may be involved in the embodiments are introduced below. It should be understood that the explanations of related concepts may be limited due to the specific circumstances of this application, but this does not mean that this application is limited to that specific situation. The specific circumstances in different embodiments may also differ, and no specific limitations are made here.

[0146] (1) Pressure sensor

[0147] A pressure sensor is a device that can sense pressure signals and convert them into usable electrical output signals according to certain rules. Pressure sensors are one of the most commonly used sensors in industrial practice, and they are widely used in various industrial automation environments, involving many industries such as water conservancy and hydropower, railway transportation, intelligent buildings, production automation, aerospace, military, petrochemical, oil wells, power, shipbuilding, machine tools, and pipelines.

[0148] In practical applications, some typical pressure sensors include resistive pressure sensors, capacitive pressure sensors, piezoelectric pressure sensors, and TENG-based pressure sensors.

[0149] Among them, resistive pressure sensors, when pressure is applied externally, the change in the contact area between the two plates under pressure causes a change in resistance. By calibrating the relationship between the resistance value and the pressure value, the pressure value can be deduced from the resistance value of the external circuit. Similarly, when pressure is applied externally, the change in the distance between the two plates of a capacitive pressure sensor under pressure causes a change in capacitance. By calibrating the relationship between the capacitance value and the pressure value, the pressure value can be deduced from the voltage value of the external circuit. When pressure is applied externally, the deformation of the two plates under external force causes a change in charge. By calibrating the relationship between the voltage value and the pressure value, the pressure value can be deduced from the voltage of the external circuit. In TENG-based pressure sensors, under external pressure, the pressure causes a change in the distance between the friction layers, and the change in charge generated by friction causes a change in the external voltage. The friction layer material is generally chosen to have a large difference in the ability to gain and lose electrons, so the external force will cause a large change in the voltage across the electrodes.

[0150] The characteristics of the four typical pressure sensors mentioned above can be summarized in Table 1. Among them, the TENG-based pressure sensor has attracted widespread attention due to its advantages over the other types of pressure sensors, such as a wide range of selectable materials, good dynamic response, fast response time, and rich details of the measured physiological signals.

[0151] Table 1. Summary of the characteristics of pressure sensors based on four principles

[0152] Type Features Piezoresistive pressure sensor Dynamic and static pressure signals can be measured, but the hysteresis phenomenon is more serious Capacitive pressure sensor High measurement accuracy, good dynamic response characteristics, but susceptible to external environmental interference (parasitic capacitance) Piezoelectric pressure sensor Simple structure, high sensitivity, but the material needs to be customized TENG-based pressure sensor Wide range of optional materials, good dynamic response, fast response time, and rich details of measured physiological signals

[0153] The embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0154] The technical solutions of the embodiments of this application will be described below from the perspective of different types of pressure sensors:

[0155] I. Pressure Sensor Based on TENG

[0156] First, the TENG-based pressure sensor provided in the embodiments of this application will be introduced. Please refer to [link / reference] for details. Figure 3 , Figure 3This is a schematic diagram of a TENG-based pressure sensor provided in an embodiment of this application. The TENG-based pressure sensor includes two friction layers (a first friction layer 301 and a second friction layer 302, respectively) and an electrode layer (which may be referred to as a first electrode layer 303). The first friction layer 301 and the second friction layer 302 are made of materials with different electron-gaining and electron-losing capabilities. For example, the materials of the friction layers can be PTFE, PET, PE, PDMS, FEP, etc. It should be noted that the materials selected for the first friction layer 301 and the second friction layer 302 must be different. The first electrode layer 301 is made of a conductive material, such as metallic materials (gold, silver, copper, etc.) or conductive materials (graphene, silver nanowires, ITO, etc.). The first friction layer 301 is connected to the first electrode layer 303. Specifically, a multi-level micro / nano structure is grown on the surface of at least one of the friction layers 301 and 302. Figure 3 The illustration shows that the surface of the first friction layer 301 includes a multi-level micro / nano structure (in reality, a multi-level micro / nano structure can also be generated on the surface of the second friction layer 302, which will not be elaborated here). This structure is used to induce a net charge of equal and opposite magnitude to the applied pressure on the first friction layer 301 and the second friction layer 302 under pressure, while also providing support. The first electrode layer 303 is used to generate a current based on the equal and opposite net charges induced on the two friction layers. Finally, by converting the current to the applied pressure (in some embodiments, this can also be done by calculating the change in voltage), the applied pressure value is deduced.

[0157] It should be noted that in this embodiment, the first electrode layer 303 can also be a conductive electrode line, and this application does not limit this. It should also be noted that in this embodiment, when only the first electrode layer 303 exists, it is grounded. Furthermore, it should be noted that in some application scenarios of this application, the friction layer can also be used as a conductive electrode layer, and this application does not limit this.

[0158] It should be noted that in some other embodiments of this application, the TENG-based pressure sensor may further include a second electrode layer; please refer to [link / reference] for details. Figure 4 , Figure 4This is another schematic diagram of a TENG-based pressure sensor provided in an embodiment of this application. The TENG-based pressure sensor includes two friction layers (a first friction layer 301 and a second friction layer 302) and two electrode layers (a first electrode layer 303 and a second electrode layer 304). The first friction layer 301 and the second friction layer 302 are made of materials with different electron-gaining and electron-losing capabilities. For example, the materials for the friction layers can be PTFE, PET, PE, PDMS, FEP, etc. It should be noted that the materials chosen for the first friction layer 301 and the second friction layer 302 must be different. The first electrode layer 301 and the second electrode layer 302 are made of conductive materials, such as metallic materials (gold, silver, copper, etc.) or conductive materials (graphene, silver nanowires, ITO, etc.). The first friction layer 301 is connected to the first electrode layer 303, and the second friction layer 302 is connected to the second electrode layer 304.

[0159] Specifically, a multi-level micro / nano structure is grown on the surface of at least one of the first friction layer 301 and the second friction layer 302. Figure 3 The illustration shows that the surface of the first friction layer 301 includes a multi-level micro / nano structure (in reality, a multi-level micro / nano structure can also be generated on the surface of the second friction layer 302, which will not be elaborated here). This structure is used to induce a net charge of equal and opposite magnitude to the applied pressure on the first friction layer 301 and the second friction layer 302 under pressure, while also providing support. The first electrode layer 303 and the second electrode layer 304 are used to generate current based on the equal and opposite net charges induced on the two friction layers. Finally, the applied pressure value is derived by converting the current to the applied pressure. For ease of explanation, in the following embodiments, the TENG-based pressure sensor is illustrated using an example with two electrode layers.

[0160] It should be noted that, in the embodiments of this application, the multi-level micro / nano structure includes at least two types of columnar structures of different heights. Figure 4 The illustration shows a periodic arrangement of two different heights of micro / nano columnar structures. In practical applications, multi-level micro / nano structures can be n different heights of micro / nano columnar structures, where n≥2.

[0161] As an example, Figure 4 This illustration shows the periodic arrangement of micro / nano columnar structures of different heights when n=2; as another example, Figure 5The illustration shows the periodic arrangement of micro / nano columnar structures of different heights when n=4. Generally, the larger the value of n, the more levels of the multi-level micro / nano structures there are, resulting in a greater variety of heights between the first friction layer 301 and the second friction layer 302. Under the action of external force, the different heights lead to different net charges generated at different locations, indirectly improving the sensitivity of the pressure sensor.

[0162] It should be noted that, in Figure 4 as well as Figure 5 In the corresponding embodiments, the micro- and nano-column structures of different heights are arranged periodically. In other embodiments of this application, in addition to periodic arrangement, they can also be arranged irregularly in random order. This application does not limit the specific arrangement.

[0163] It should also be noted that, in the embodiments of this application, the applied pressure can be applied to the first electrode layer 303, the second electrode layer 304, or both the first electrode layer 303 and the second electrode layer 304 simultaneously. Figure 4 (This illustration shows the application applied to two electrode layers), but the specific application depends on the actual application scenario of the TENG-based pressure sensor, and this application does not limit it.

[0164] It should also be noted that, in some embodiments of this application, the micro-nano columnar structure can be considered as a first-order micro-nano structure. To increase the friction area between the first friction layer 301 and the second friction layer 302, micro-nano processing can be performed on the micro-nano columnar structure. Specifically, micro-nano-level burr structures (such as...) can be etched onto the micro-nano columnar structure using an etching process. Figure 4 or Figure 5 As shown in the figure, it can also be called a secondary micro-nano structure. This burr structure can be used to increase the friction area between the first friction layer 301 and the second friction layer 302 under the action of applied pressure, thereby increasing the amount of net charge induced on the two friction layers and improving the detection sensitivity of the pressure sensor.

[0165] It should also be noted that, in some embodiments of this application, the shape of the micro / nano columnar structure can be any processable shape with a certain height, for example, it can be any one or more of the following: cylindrical, polygonal prism, conical, polygonal pyramidal, hemispherical, inverted pyramidal, and pyramidal. Figure 4 and Figure 5 In the illustrated embodiment, the schematic micro / nano columnar structure is cubic in shape (a type of polygonal prism). Figure 6 In the diagram, the micro / nano columnar structures are shown in semi-circular shape (assuming n=2, meaning that two different heights of micro / nano columnar structures are periodically arranged); while...Figure 7 In the illustration, the shapes of the micro-nano columnar structures include a mixture of semi-circular and cubic shapes (assuming n=2, that is, including the periodic arrangement of micro-nano columnar structures of two different heights). Specific examples will not be given in this application.

[0166] It should also be noted that in some other embodiments of this application, a micro / nano columnar structure can be made of a single material. Specifically, micro / nano columnar structures of the same height can be made of one material, while micro / nano columnar structures of a different height can be made of a different material. Different materials have different Young's moduli. As an example, see [reference needed]. Figure 8 , Figure 8 The schematic diagram (a) in the figure illustrates that each micro-nano columnar structure is made of the same material A; while Figure 8 The sub-schematic diagram (b) illustrates that the micro-nano columnar structures at the same height are made of one material (i.e., material A), while the micro-nano columnar structures at another height are made of another material (i.e., material B). In short, each individual micro-nano columnar structure is made of one material.

[0167] It should also be noted that in some other embodiments of this application, a micro-nano columnar structure can also be made of at least two materials with different Young's moduli. Specifically, in one particular implementation of this application, the micro-nano columnar structure can be obtained by stacking at least two micro-nano sub-columnar structures, with each sub-columnar structure corresponding to a material with a Young's modulus.

[0168] It should be noted that, in some embodiments of this application, the at least two micro / nano-sized sub-pillar structures include, but are not limited to:

[0169] 1) At least two micro / nano-sized sub-columnar structures have the same cross-sectional area. For example, suppose there are four sub-columnar structures, A, B, C, and D. From the top view of the pressure sensor, the cross-sectional area of ​​these four sub-columnar structures is the same, S0. For further details, please refer to [reference needed]. Figure 9 This will not be elaborated upon here. It is important to note that the heights of these four sub-column structures can be the same or different. Figure 9 The illustrations represent different scenarios, which will not be elaborated upon here.

[0170] 2) If at least two micro / nano-scale sub-columnar structures have different cross-sectional areas, they are stacked sequentially in descending order of cross-sectional area. For example, suppose there are four sub-columnar structures, A, B, C, and D, with cross-sectional lengths S1, S2, S3, and S4, where S1 < S2 < S3 < S4. The stacking arrangement on the at least one friction layer would be: D is located on the surface of the at least one friction layer, C is stacked on top of D, B is stacked on top of C, and A is stacked on top of B. Specifically, the stacking method can be as follows: Figure 10 Neutron columnar structures can be stacked with one side aligned (i.e., forming a stepped shape), or as... Figure 11 The neutron columnar structures are stacked with their sides asymmetrically arranged; however, this application does not limit the specific arrangement. It should also be noted that in this embodiment, the heights of the four sub-columns can be the same or different. Figure 10 as well as Figure 11 This illustrates the same situation, and details will not be elaborated here. It is also important to note that... Figure 10 as well as Figure 11 The illustrated micro / nano columnar structures have the same height. However, in some embodiments of this application, the heights of the micro / nano columnar structures formed by stacking sub-columnar structures made of materials with different Young's moduli can also differ. That is, multiple micro / nano columnar structures may have at least two different heights, such as... Figure 12 As shown, the stepped micro / nano columnar structure includes two heights. In reality, it can have many more heights, which will not be elaborated here.

[0171] Furthermore, in practical applications, when the external pressure is relatively high, the first friction layer 301 and the second friction layer 302 may become completely adhered together. This can lead to the failure of the pressure sensor, reducing its sensitivity and narrowing its pressure measurement range. To reduce the probability of this happening, in some embodiments of this application, at least one of the friction layers 301 and 302 may also grow some target micro / nano structures of a predetermined height, referred to as the first predetermined height h1. This predetermined height provides support under external pressure, preventing the first friction layer 301 and the second friction layer 302 from directly adhering under the pressure. It should be noted that in the embodiments of this application, the first predetermined height h1 is greater than the height of any one of at least two different heights of micro / nano columnar structures.

[0172] To facilitate understanding, the following example is provided. Please refer to the detailed explanation below. Figure 13 , Figure 13 A schematic diagram of a TENG-based pressure sensor with a target micro / nano structure having a first preset height, provided in an embodiment of this application, is given by...Figure 13 It can be seen that, under the support of the target micro-nano structure, the pressure applied from the outside is not easy to make the two friction layers stick together completely, thereby expanding the pressure measurement range of the TENG-based pressure sensor and improving its sensitivity.

[0173] In the above Figures 3 to 13 Based on the corresponding embodiments, the processing procedure of the two friction layers of the TENG-based pressure sensor will be described below. Please refer to [link / reference] for details. Figure 14 , Figure 14 This is a schematic diagram of the processing of the friction layer provided in an embodiment of this application, wherein the first friction layer 301 is friction layer 1 and the second friction layer 302 is friction layer 2. The processing includes the following steps:

[0174] 1. Friction layer treatment

[0175] For the fabrication process of the multi-level structure design, a single friction layer or multiple friction layers can be pre-processed and photolithographically processed to obtain multiple micro-nano columnar structures of different heights, i.e., the multi-level micro-nano structure, also known as the first-level micro-nano structure, which can be circular or polygonal; this application does not specifically limit this. Subsequently, an etching process is used to etch the second-level micro-nano structure, forming a burr structure, which is used to improve the sensitivity of the TENG-based pressure sensor.

[0176] It should be noted that, in the embodiments of this application, the multi-level micro-nano structure can be formed into multiple first-level micro-nano columnar structures of different heights by means of nanoimprinting, mold demolding, etc.

[0177] It should also be noted that, in some embodiments of this application, if the multi-level micro / nanostructures are formed by stacking to create micro / nanostructures of different or the same height (e.g., Figures 9-12 As shown in the figure, the processing method can be to stack multiple materials with different Young's moduli and perform photolithography using photomasks of different sizes and shapes to form a multi-step primary micro-nano structure, and then perform secondary micro-nano processing to obtain a burr structure.

[0178] 2. Electrode treatment and leads

[0179] In the embodiments of this application, electrodes can be processed on the outer surface of the friction layer by means of coating, bonding, spin coating, etc., and wires can be led out.

[0180] 3. Packaging process

[0181] The processed membrane materials are stacked, that is, an electrode layer is attached to the friction layer, and then encapsulated by methods such as coating and pressing.

[0182] Furthermore, it should be noted that in the above embodiments of this application, the method of growing target micro / nano structures of a first predetermined height h1 on at least one of the first friction layer 301 and the second friction layer 302 to provide support under external pressure is relatively complex. Therefore, to reduce the complexity of the process, in some other embodiments of this application, an isolation layer can also be added. Please refer to [link to relevant documentation] for details. Figure 15 , Figure 15 This is another schematic diagram of the structure of the TENG-based pressure sensor provided in the embodiments of this application. Figure 15 In addition to the first friction layer 301, second friction layer 302, first electrode layer 303, and second electrode layer 304 described above, the TENG-based pressure sensor also includes an additional isolation layer 305 of a predetermined height between the first friction layer 301 and the second friction layer 302. This predetermined height can be referred to as the second predetermined height h2, and the second predetermined height h2 is greater than the height of any one of the at least two different heights of the micro / nano columnar structures. The isolation layer 305 has at least one pore with a predetermined aperture. Figure 15 (Not shown in the diagram) This structure provides support under external pressure to prevent the first friction layer 301 and the second friction layer 302 from directly adhering to each other under the pressure. In this case, a multi-level micro / nano structure grows within the pores of the insulating layer 305, such as... Figure 16 As shown, Figure 16 This is a schematic diagram of a pore in the isolation layer 305 where a multi-level micro / nano structure is grown, as provided in an embodiment of this application.

[0183] It should be noted that the isolation layer 305 can also be designed as a splicing of sub-isolation layers of different heights. For example, the isolation layer 305 can be composed of m sub-isolation layers, and the height of each sub-isolation layer can be set differently. That is, the second preset height h2 can be one height value or multiple height values. This application does not limit this in any way.

[0184] It should be noted that, in some embodiments of this application, the shape of at least one hole on the isolation layer 305 can be any machinable shape, for example, it can be circular (e.g., Figure 17 (as shown in sub-schematic in (a)) can also be elliptical, or it can be a polygon. Furthermore, it can be a regular polygon, such as an equilateral triangle or a square (e.g. Figure 17 The hole shape in the isolation layer 305 can be a hexagon, etc., as shown in sub-schematic (b) in the diagram, or an irregular polygon, such as a trapezoid or a scalene triangle. Specifically, this application does not limit the shape of the hole in the isolation layer 305. In addition, not only can the shape of the hole be set according to the requirements, but the opening area of ​​the hole can also be set by the user. This application does not limit this.

[0185] Similarly, in the above Figures 15 to 17 Based on the corresponding embodiments, the processing procedures for the two friction layers and the isolation layer of the TENG-based pressure sensor are described below. Please refer to [link / reference] for details. Figure 18 , Figure 18 This is a schematic diagram illustrating the processing of the friction layer and the isolation layer provided in the embodiments of this application. The first friction layer 301 is friction layer 1, and the second friction layer 302 is friction layer 2. The processing includes the following steps:

[0186] 1. Friction layer treatment

[0187] For the fabrication process of the multi-level structure design, a single friction layer or multiple friction layers can be pre-processed and photolithographically processed to obtain multiple micro-nano columnar structures of different heights, i.e., the multi-level micro-nano structure, also known as the first-level micro-nano structure, which can be circular or polygonal; this application does not specifically limit this. Subsequently, an etching process is used to etch the second-level micro-nano structure, forming a burr structure, which is used to improve the sensitivity of the TENG-based pressure sensor.

[0188] It should be noted that, in the embodiments of this application, the multi-level micro-nano structure can be formed into multiple first-level micro-nano columnar structures of different heights by means of nanoimprinting, mold demolding, etc.

[0189] It should also be noted that, in some embodiments of this application, if the multi-level micro / nanostructures are formed by stacking to create micro / nanostructures of different or the same height (e.g., 8- Figure 12 As shown in the figure, the processing method can be to stack multiple materials with different Young's moduli and perform photolithography using photomasks of different sizes and shapes to form a multi-step primary micro-nano structure, and then perform secondary micro-nano processing to obtain a burr structure.

[0190] 2. Electrode treatment and leads

[0191] In the embodiments of this application, electrodes can be processed on the outer surface of the friction layer by means of coating, bonding, spin coating, etc., and wires can be led out.

[0192] 3. Isolation layer treatment

[0193] First, the surface of the isolation layer is pretreated. Then, methods such as mold molding, embossing, mechanical drilling, and laser drilling can be used to drill holes in the isolation layer.

[0194] 4. Packaging Process

[0195] The processed membrane materials are stacked, that is, an electrode layer is attached to the friction layer and an isolation layer is placed between the two friction layers, and encapsulation is carried out by means of coating and pressing.

[0196] In the embodiments described above in this application, the measurement range of the TENG-based pressure sensor can be expanded and its sensitivity improved by using a multi-level micro / nano structure design or by combining an isolation layer with a multi-level micro / nano structure. Furthermore, by synergistically combining the area and height of the multi-level micro / nano structure, the TENG-based pressure sensor maintains the same or similar sensitivity under various static forces; alternatively, by designing an isolation layer (height, aperture, shape, etc.) and a multi-level structure (height, area, shape, distribution), the sensitivity of the TENG-based pressure sensor under different static forces can be made approximately the same.

[0197] The following describes the application scenarios of the TENG-based pressure sensor provided in the embodiments of this application, including but not limited to its application in the following devices:

[0198] 1. Deployed in wearable devices

[0199] Human pulse waves are crucial for detecting physiological information. Measuring pulse waves via pressure requires sensors with extremely high sensitivity. Furthermore, to achieve accurate pulse wave measurements under varying static forces, the pressure sensor needs to maintain high sensitivity under different static forces. Therefore, the TENG-based pressure sensor provided in the above embodiments of this application can be deployed in wearable devices to monitor pulse fluctuations, effectively improving detection sensitivity.

[0200] 2. Deployed on electronic devices with touch screens

[0201] Electronic devices with touchscreens are a new type of computer equipment. For ease of operation, touchscreens replace mice, keyboards, and other similar devices. When using them, the user first touches the touchscreen at the front of the electronic device with their finger or another object. The device then locates and selects information input based on the icon or menu position touched by the finger.

[0202] With the development of multimedia technology and graphical user interfaces, the requirements for touchscreen sensitivity are becoming increasingly stringent. Therefore, the TENG-based pressure sensor provided in the above embodiments of this application can be deployed in electronic devices with touchscreens to detect touch actions, effectively improving detection sensitivity.

[0203] In addition to the two typical application scenarios described above, the pressure sensor provided in this application embodiment can also be used on wheeled mobile devices (such as indoor robots, vehicles (such as autonomous vehicles, ordinary vehicles, etc.)). For example, it can be used to detect the pressure of vehicle tires, etc. This application will not provide further examples.

[0204] II. Pressure sensors of piezoresistive, piezoresistive, and piezoelectric types

[0205] The multi-level micro / nano structure proposed in this application can be applied not only to TENG-based pressure sensors but also to other types of pressure sensors. These pressure sensors can be piezoresistive, piezocapacitive, or piezoelectric; this application does not specifically limit their application. Please refer to [link to relevant documentation] for details. Figure 19 , Figure 19 This is a schematic diagram of a pressure sensor provided in an embodiment of this application. The pressure sensor includes a functional layer (which may be referred to as the first functional layer 401) and two electrode layers (the first electrode layer 402 and the second electrode layer 403, respectively). The first electrode layer 402 and the second electrode layer 403 are made of conductive materials, such as metallic materials (gold, silver, copper, etc.) or conductive materials (graphene, indium tin oxide (ITO), silver nanowires, etc.). The first functional layer 401 is connected to one of the first electrode layers 402 or the second electrode layer 403.

[0206] The surface of the first functional layer 401 includes at least two types of micro / nano columnar structures of different heights, used to sense a first signal corresponding to the pressure on the first functional layer 401 under pressure; the first electrode layer 402 and the second electrode layer 403 are used to generate a second signal based on the first signal. It should be noted that, in this embodiment, the micro / nano columnar structures of different heights grown on the surface of the first functional layer 401 are similar to the TENG-based pressure sensor in Method 1 above, and can be referred to the description in Method 1 above for details, which will not be repeated here.

[0207] It should be noted that, in the embodiments of this application, the first electrode layer 402 and / or the second electrode layer 403 can also be conductive wires, and the electrode layers can also be a combination of layered materials, interpolated electrodes, and wires, etc. Figure 20 The example illustrates the case where the first electrode layer 402 is a conductive line (the case where the second electrode layer 403 is a wire is similar and will not be described in detail here).

[0208] It should also be noted that in some embodiments of this application, the functional layer may be one or two, and this application does not limit this. Specifically, the pressure sensor may also include one functional layer, as detailed in [reference needed]. Figure 21 , Figure 21 This is another structural schematic diagram of the pressure sensor provided in an embodiment of this application. The additional functional layer can be referred to as the second functional layer 404.

[0209] It should also be noted that in some embodiments of this application, the first functional layer 401 may additionally include an isolation layer of a preset height; please refer to [link / reference] for details. Figure 22 , Figure 22 This is another structural schematic diagram of the pressure sensor provided in this application embodiment. The preset height of the isolation layer 405 can be referred to as the second preset height, which is greater than the height of any one of the at least two different heights of the micro / nano columnar structures. The isolation layer 405 has at least one pore with a preset aperture, and the isolation layer 405 is used to provide support under external pressure to prevent the two electrode layers (assuming the electrode layers are not electrode wires) from directly adhering under the pressure. In this case, the multi-level micro / nano structure grows within the pores of the isolation layer. Specifically, the arrangement of the isolation layer 405 is similar to that of the TENG-based pressure sensor in the above-described method one, and the details can be found in the description of the above-described method one, which will not be repeated here.

[0210] It should also be noted that, in some embodiments of this application, when the first signal is a first resistor (i.e., the pressure sensor is a piezoresistive type), the second signal is a second resistor, and the functional layer is made of a material that has resistive properties that change under different pressures (i.e., has resistive characteristics); or, when the first signal is a first capacitor (i.e., the pressure sensor is a piezoresistive type), the second signal is a second capacitor, and the functional layer is made of a material that has capacitive properties that change under different pressures (i.e., has capacitive characteristics); or, when the first signal is a first voltage (i.e., the pressure sensor is a piezoelectric type), the second signal is a second voltage, and the functional layer is made of a material that has piezoelectric properties that change under different pressures (i.e., has piezoelectric characteristics).

[0211] Because different types of pressure sensors can all be structurally... Figures 19-22 The structure shown is schematic, but the materials and properties used in the functional layers will differ slightly. The following sections will explain each type of pressure sensor based on its principle:

[0212] (1) Piezoresistive pressure sensor

[0213] Taking a piezoresistive sensor as an example, the functional layer can be composed of materials with conductive properties, such as graphene, carbon nanotubes, graphene oxide, graphite, copper, silver nanowires, ITO, etc.

[0214] The structure of the functional layer can consist of conductive materials and a substrate material, such as... Figure 23 As shown, Figure 23This is a schematic diagram of the functional layer provided in an embodiment of this application. The substrate material can be selected from materials such as PTFE, PET, PE, PDMS, and FEP. Optionally, the substrate material can be composed of structures such as salt grains, sand grains, and micro / nano spheres of different sizes. The conductive material can be fabricated on the surface of the substrate material by processing methods such as vapor deposition, sputtering, and spin coating. The fibrous structure on the surface can be generated by etching.

[0215] It should be noted that in some embodiments of this application, a substrate material may be omitted, and the conductive material may be directly deployed on the electrode layer, such as... Figure 24 As shown.

[0216] The working principle of a piezoresistive sensor: When external pressure is applied, the resistance changes. This resistance change is mainly caused by changes in contact area and internal structure. Employing a multi-level micro-nano support structure, the isolation structure can expand the sensor's measurement range. Simultaneously, the different heights of the structure allow for contact between the upper and lower electrode surfaces. If the height of the isolation layer is h, then in a traditional structure, the electrode surface deformation needs to exceed h to produce a large response. With a functional layer protrusion height s, the deformation of the upper and lower electrode surfaces (hs) can produce a larger change in contact area, resulting in a larger change in output resistance. Therefore, the protrusion height can reduce the sensor's detection limit. The design of different heights allows the sensor to have higher detection sensitivity under different static forces. Figure 22 As shown, under external pressure, the electrode plate is in contact with the protrusions, resulting in a low detection limit and high sensitivity under low pressure.

[0217] (2) Capacitive pressure sensor

[0218] Taking capacitive sensors as an example, the functional layer can be implemented using non-conductive materials.

[0219] The working principle of a capacitive sensor: When external pressure is applied, it causes a change in the distance between the upper and lower electrodes of the sensor, altering the dielectric constant of the functional layer and thus changing the capacitance. The change in the dielectric constant of the functional layer is primarily due to deformation caused by pressure. An isolation layer can extend the sensor's measurement range. Furthermore, structures with different heights allow for contact between the upper and lower electrodes. If the height of the isolation layer is *h*, a traditional structure requires electrode deformation exceeding *h* to produce a large response. If the height of the functional layer protrusion is *s*, then deformation between the upper and lower electrodes (*h**) can create a larger contact area change, causing deformation of the functional layer, leading to a change in the dielectric constant and consequently a larger change in the output capacitance. Therefore, the protrusion height can reduce the sensor's detection limit. Designs with different heights allow the sensor to have higher detection sensitivity under different static forces. Figure 22As shown, under external pressure, the electrode plate is in contact with the protrusions, resulting in a low detection limit and high sensitivity under low pressure.

[0220] (3) Piezoelectric pressure sensor

[0221] Taking piezoelectric sensors as an example, the functional layer can be made of piezoelectric materials and piezoelectric electrets.

[0222] The working principle of a piezoelectric sensor: When external pressure is applied, it causes a change in the distance between the upper and lower electrodes of the sensor or a change in the piezoelectric voltage of the functional layer, resulting in a change in capacitance. The change in the dielectric constant of the functional layer is mainly due to the deformation of the functional layer caused by pressure, which in turn causes a change in the piezoelectric voltage. The isolation layer can expand the sensor's measurement range. Furthermore, the structure with different heights allows the upper and lower electrodes to contact each other. If the height of the isolation layer is h, then in a traditional structure, the electrode deformation needs to exceed h to produce a large response. If the height of the functional layer protrusion is s, then the deformation of the upper and lower electrodes (hs) can produce a larger change in contact area, thereby causing deformation of the functional layer, a change in piezoelectric voltage, and thus a larger change in output capacitance. Therefore, the protrusion height can reduce the sensor's detection limit. The design with different heights allows the sensor to have higher detection sensitivity under different static forces. Figure 22 As shown, under external pressure, the electrode plate is in contact with the protrusions, resulting in a low detection limit and high sensitivity under low pressure.

[0223] In the above embodiments of this application, the multi-level micro-nano structure (i.e., at least two kinds of micro-nano columnar structures with different heights) can be applied not only to pressure sensors based on triboelectric nanogenerators, but also to pressure sensors of the piezoresistive, piezoresistive, and piezoelectric types, and has wide applicability.

Claims

1. A pressure sensor based on triboelectric nanogenerators, characterized in that, include: A first friction layer, a second friction layer, and a first electrode layer, wherein the first friction layer and the second friction layer are made of materials with different electron gain and loss capabilities, the first electrode layer is made of a conductive material, and the first friction layer is connected to the first electrode layer. The surface of at least one of the first and second friction layers includes at least two types of micro / nano columnar structures of different heights, for inducing a net charge of equal and opposite magnitude to the pressure on the first and second friction layers under pressure. The micro / nano columnar structures are made of at least two materials with different Young's moduli, and the micro / nano columnar structures are formed by stacking at least two micro / nano sub-columnar structures, each of which is made of a material with a Young's modulus. The first electrode layer is used to generate current based on the net charge.

2. The sensor according to claim 1, characterized in that, The sensor also includes: The second electrode layer is made of a conductive material, and the second friction layer is connected to the second electrode layer. The first electrode layer, for generating current based on the net charge, includes: The first electrode layer and the second electrode layer are used to generate current based on the net charge.

3. The sensor according to claim 1, characterized in that, The at least two micro-nano sub-column structures have the same cross-sectional area; or, The at least two micro-nano sub-column structures are stacked sequentially in descending order of cross-sectional area.

4. The sensor according to claim 1, characterized in that, The at least one friction layer further includes: The target micro / nano structure has a first preset height, which is greater than the height of any one of the at least two different heights of micro / nano columnar structures.

5. The sensor according to claim 1, characterized in that, The sensor also includes: A second preset height isolation layer, the isolation layer having at least one pore of a preset diameter, the isolation layer being located between the first friction layer and the second friction layer, the micro-nano columnar structure being deployed within the pore of the isolation layer, and the second preset height being greater than the height of any one of the at least two different heights of the micro-nano columnar structure.

6. The sensor according to claim 5, characterized in that, The shape of the at least one hole includes any one or more of the following: Circle, oval, polygon.

7. The sensor according to any one of claims 1-6, characterized in that, The shape of the micro / nano columnar structure includes any one or more of the following: Cylindrical, polygonal prism, conical, polygonal pyramid, hemispherical, inverted pyramid, pyramid.

8. The sensor according to any one of claims 1-6, characterized in that, The at least two micro / nano columnar structures of different heights are periodically arranged on the at least one friction layer.

9. The sensor according to any one of claims 1-6, characterized in that, The micro-nano columnar structure is etched with burr structures.

10. The sensor according to any one of claims 1-6, characterized in that, The sensor is deployed in a wearable device to monitor pulse fluctuations.

11. The sensor according to any one of claims 1-6, characterized in that, The sensor is deployed on an electronic device with a touchscreen to detect touch actions.

12. A pressure sensor based on triboelectric nanogenerators, characterized in that, include: A first friction layer, a second friction layer, and a first electrode layer, wherein the first friction layer and the second friction layer are made of materials with different electron gain and loss capabilities, the first electrode layer is made of a conductive material, and the first friction layer is connected to the first electrode layer. The surface of at least one of the first and second friction layers includes micro-nano columnar structures for inducing a net charge of equal and opposite magnitude to the pressure on the first and second friction layers under pressure. The micro-nano columnar structures are made of at least two materials with different Young's moduli, and the micro-nano columnar structures are formed by stacking at least two micro-nano sub-columnar structures, each of which is made of a material with a Young's modulus. The first electrode layer is used to generate current based on the net charge.

13. The sensor according to claim 12, characterized in that, The sensor also includes: The second electrode layer is made of a conductive material, and the second friction layer is connected to the second electrode layer. The first electrode layer, for generating current based on the net charge, includes: The first electrode layer and the second electrode layer are used to generate current based on the net charge.

14. The sensor according to claim 12, characterized in that, The at least two micro-nano sub-column structures have the same cross-sectional area; or, The at least two micro-nano sub-column structures are stacked sequentially in descending order of cross-sectional area.

15. The sensor according to claim 12, characterized in that, The multiple micro / nano columnar structures have at least two different heights.

16. The sensor according to claim 15, characterized in that, Micro- and nano-columnar structures of varying heights are periodically arranged on at least one friction layer.

17. The sensor according to any one of claims 12-16, characterized in that, The at least one friction layer further includes: The target micro / nano structure has a first preset height, which is greater than the height of any one of at least two different types of micro / nano columnar structures.

18. The sensor according to any one of claims 12-16, characterized in that, The sensor also includes: A second preset height isolation layer, the isolation layer having at least one pore of a preset diameter, the isolation layer being located between the first friction layer and the second friction layer, the micro-nano columnar structure being deployed within the pore of the isolation layer, and the second preset height being greater than the height of any one of at least two different heights of micro-nano columnar structures.

19. An electronic device, characterized in that, The device includes a pressure sensor as described in any one of claims 1-18.

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