Adhesive vertical micro-capacitive flexible mechanical sensor and its manufacturing method and application

Abstract

The present invention discloses an attachable vertical micro-capacitive flexible mechanical sensor and its manufacturing method and application. The capacitive flexible mechanical sensor includes a flexible substrate, a sensitive layer and at least two electrodes. The sensitive layer is arranged on the surface of the flexible substrate; the sensitive layer includes a capacitor micro-electrode plate arranged on the surface of the flexible substrate and a nanowire conductive network layer arranged on the surface of the capacitor micro-electrode plate. The capacitor micro-electrode plate includes a first capacitor micro-electrode plate and a second capacitor micro-electrode plate having a first spiral structure and a second spiral structure respectively. The first spiral structure and the second spiral structure cooperate to form a three-dimensional double-helical micro-nano structure. A polymer dielectric layer is also distributed between the first capacitor micro-electrode plate and the second capacitor micro-electrode plate. The capacitor micro-electrode plate in the flexible mechanical sensor provided by the present invention adopts a fingerprint-like "vortex" micro-nano structure, which can achieve a selective response with high sensitivity to pressure and shear force, and also has the advantages of high precision, high reliability, and long life.

Description

Technical Field

[0001] The present invention relates to a mechanical sensor, in particular to an attachable vertical micro-capacitive flexible mechanical sensor and a manufacturing method and application thereof, belonging to the field of micro-electromechanical technology. Background Art

[0002] Although prosthetic technology has made great progress in recent years, the rejection and abandonment rate of prosthetics is still very high, mainly due to the lack of safe and effective tactile perception feedback and bionic compliant control functions. As the most advanced tactile sensor that is the source of perception information, its signal detection accuracy, recognition and integration with human physiological signals are the information basis for the wearer to establish basic control actions such as natural hand compliant grasping, gripping and twisting through the back-end neural feedback channel, which has become a research focus in the field. In recent years, with the rise and rapid development of flexible electronic technology, it has become possible for prosthetic hands to achieve natural tactile perception functions similar to human flexible skin by taking advantage of the advantages of flexible electronic sensors such as lightness, thinness and good conformity with curved surfaces.

[0003] At present, the research on flexible electronic sensors is mainly aimed at the sensitivity and stability of pressure sensing, but solving the problem of effective discrimination of touch position and tactile pattern, especially the accurate identification of pressure and shear force (i.e. static friction and sliding friction), is an important challenge in the field of flexible sensors. The reported research work mainly uses pressure sensing arrays and is assisted by signal processing technology. There are problems such as large amount of collected data, poor intuitiveness, and complex signal processing mode. This is too complicated for application in bionic prosthetic hands or robot bionic skin, and cannot be directly applied to prosthetic hand perception. There are currently no reports on single flexible sensor devices that can distinguish between pressure and shear force. This is a challenge. The reason is that the sensitive materials or micro-nano structures used in the generally reported flexible mechanical sensors have exactly the same response mode or method to pressure and shear force. Summary of the invention

[0004] The main purpose of the present invention is to provide an adaptable vertical micro-capacitive flexible mechanical sensor with a fingerprint-imitation "vortex" micro-nano structure and its manufacturing method and application, so as to overcome the shortcomings of the prior art.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0006] An embodiment of the present invention provides an attachable vertical micro-capacitive flexible mechanical sensor, which includes a flexible substrate, a sensitive layer and at least two electrodes, wherein the sensitive layer is arranged on the surface of the flexible substrate, and the at least two electrodes are arranged on the sensitive layer at intervals;

[0007] Among them, the sensitive layer includes a capacitor micro-electrode plate arranged on the surface of a flexible substrate and a nanowire conductive network layer arranged on the surface of the capacitor micro-electrode plate. The capacitor micro-electrode plate includes a first capacitor micro-electrode plate and a second capacitor micro-electrode plate respectively having a first spiral structure and a second spiral structure. The first spiral structure and the second spiral structure cooperate to form a three-dimensional double-helical micro-nano structure imitating a fingerprint vortex. A polymer dielectric layer is also distributed between the first capacitor micro-electrode plate and the second capacitor micro-electrode plate.

[0008] Furthermore, the height of the first capacitor microplate and the second capacitor microplate is 10-50 μm, the width is 5-20 μm, the number of spiral turns is 10-50 turns, and the spacing between the first capacitor microplate and the second capacitor microplate is greater than 30 μm and less than or equal to 100 μm.

[0009] Furthermore, the nanowire conductive network layer comprises a metal nanowire three-dimensional network conductive film having a three-dimensional mesh interconnected structure formed by a plurality of metal nanowires interwoven with each other.

[0010] Furthermore, the metal nanowires include any one of silver nanowires, copper nanowires, gold nanowires, and nickel nanowires, or a combination of two or more thereof, but are not limited thereto.

[0011] Furthermore, the thickness of the metal nanowire three-dimensional network conductive film is 2 to 10 μm.

[0012] Furthermore, the flexible substrate, the sensitive layer and the polymer dielectric layer are integrated into one, and the nanowire conductive network layer and the surface of the capacitor micro-electrode plate form a continuous integrated interface structure.

[0013] Furthermore, the electrode is an electrode wire, one end of the electrode wire is electrically connected to the nanowire conductive network layer, and the other end is led out from the surface of the nanowire conductive network layer.

[0014] Furthermore, the material of the polymer dielectric layer includes any one or a combination of two or more of thermoplastic elastomer, polyvinyl alcohol, polydimethylsiloxane, and polyimide, but is not limited thereto.

[0015] Furthermore, the material of the flexible substrate includes any one or a combination of two or more of polyvinyl alcohol, polydimethylsiloxane, polydimethylsiloxane, polyethylene terephthalate, polyimide and polyethylene, but is not limited thereto.

[0016] Furthermore, the thickness of the flexible substrate is 20-300 μm.

[0017] Furthermore, the capacitor micro-electrode plate is integrally formed with the flexible substrate, and the material of the capacitor micro-electrode plate is the same as that of the flexible substrate. The material of the capacitor micro-electrode plate includes any one or a combination of two or more of polyvinyl alcohol, polydimethylsiloxane, polydimethylsiloxane, polyethylene terephthalate, polyimide and polyethylene, but is not limited to this.

[0018] Furthermore, the capacitive flexible mechanical sensor has a thickness of 190 to 500 μm.

[0019] Another aspect of the present invention is to provide a method for manufacturing the above-mentioned vertical micro-capacitive flexible mechanical sensor, which comprises:

[0020] A template having a patterned groove on its surface is provided, wherein the patterned groove comprises a first groove and a second groove having a first spiral structure and a second spiral structure respectively, wherein the first spiral structure and the second spiral structure cooperate to form a three-dimensional double-spiral micro-nano structure imitating a fingerprint vortex pattern;

[0021] Applying a metal nanowire dispersion on the surface of the template to form a metal nanowire three-dimensional network conductive film;

[0022] Removing the metal nanowire three-dimensional network conductive film in the area other than the patterned groove on the surface of the template, so that the metal nanowire three-dimensional network conductive film remaining in the first groove and the second groove serves as a nanowire conductive network layer;

[0023] A prepolymer for forming a capacitor micro-electrode plate and a flexible substrate is coated on the surface of the template, and then the prepolymer is cured to form a capacitor micro-electrode plate and a flexible substrate, and the flexible substrate, the capacitor micro-electrode plate and the nanowire conductive network layer that are combined with each other are separated from the template, wherein the capacitor micro-electrode plate is integrally formed on the surface of the flexible substrate, and the nanowire conductive network layer is arranged on the surface of the capacitor micro-electrode plate to construct a sensitive layer, and the capacitor micro-electrode plate includes a first capacitor micro-electrode plate and a second capacitor micro-electrode plate having a first spiral structure and a second spiral structure respectively, and the first spiral structure and the second spiral structure cooperate to form a three-dimensional double-helical micro-nano structure imitating a fingerprint vortex;

[0024] A polymer dielectric material is filled at least between the first capacitor micro-electrode plate and the second capacitor micro-electrode plate to form a polymer dielectric layer.

[0025] Furthermore, the manufacturing method specifically includes: coating a metal nanowire dispersion with a solubility of 1-10wt% on the surface of the template, and then drying to form a three-dimensional network conductive film of metal nanowires with a three-dimensional mesh interconnected structure.

[0026] Furthermore, the manufacturing method specifically includes: removing the metal nanowire three-dimensional network conductive film in the area outside the patterned groove on the surface of the template by mechanical stripping, while retaining the metal nanowire three-dimensional network conductive film located in the first groove and the second groove.

[0027] Furthermore, the manufacturing method specifically includes: coating a polymer dielectric material on the surface of a flexible substrate having a sensitive layer bonded thereon, and then curing the material to form a polymer dielectric layer.

[0028] Furthermore, the manufacturing method also includes: electrically combining the nanowire conductive network layer on the surface of the first electrode plate and the second electrode plate with one end of at least one electrode wire respectively, and leading the other end of the electrode wire out from the surface of the nanowire conductive network layer.

[0029] Furthermore, the first groove and the second groove have a depth of 10 to 50 μm, a width of 5 to 20 μm, a number of spiral turns of 10 to 50, and a distance between the first groove and the second groove is greater than 30 μm and less than or equal to 100 μm.

[0030] An embodiment of the present invention also provides a tactile nerve pulse signal circuit system, which includes: the above-mentioned attachable vertical micro-capacitive flexible mechanical sensor, and a functional circuit for connecting with the above-mentioned attachable vertical micro-capacitive flexible mechanical sensor to form a signal conversion.

[0031] Furthermore, the attachable vertical micro-capacitive flexible mechanical sensor and the functional circuit are also connected to a power source to form a working circuit, and the function of the circuit system is to convert the voltage telephone signal output by the sensor into a pulse signal with frequency characteristics.

[0032] Compared with the prior art, the advantages of the present invention include:

[0033] 1) The present invention simulates the human fingerprint "vortex" micro-nano structure to accurately sense the position and pattern of an object, constructs a vertical micro-capacitive structure flexible mechanical sensor with a double-helix micro-nano structure electrode plate, and establishes a theoretical mechanism for the deformation response mode of the spiral micro-nano structure under radial vertical pressure, tangential static friction and sliding friction. Without the need for complex signal analysis or algorithms, the single bionic micro-nano structure flexible mechanical sensor can accurately sense and identify pressure, static friction and sliding friction;

[0034] 2) The present invention provides an adaptable capacitive flexible mechanical sensor which is thin, light, and soft, and can be processed into a variety of shapes. It has the advantages of being wearable and attachable. In particular, the electrode plate thereof adopts a fingerprint-like "vortex" micro-nano structure, which can achieve a selective response to pressure and shear force with high sensitivity. It also has the advantages of high precision, high reliability, and long life.

[0035] 3) The preparation process of the vertical micro-capacitive flexible mechanical sensor provided by the embodiment of the present invention is simple and controllable, the raw materials are cheap and readily available, and it is suitable for large-scale industrial production;

[0036] 4) The embodiment of the present invention also constructs a tactile nerve pulse signal circuit system, which realizes the conversion of different sensor response signals into specific pulse frequency electrical signals through circuit signal processing, so as to meet the requirements of matching with nerve pulse signals, provide a powerful method for further integration of perception signals and human physiological signals, and provide a signal basis for human-machine interface interaction and control, thus completing the ultra-sensitive perception realm of "human-device" fusion of bionic prostheses. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1a , Figure 1b , Figure 1c , Figure 1d They are respectively actual optical photographs of a vertical micro-capacitive flexible mechanical sensor that can be applied and has a fingerprint-like "vortex" micro-nano structure in a typical embodiment of the present invention;

[0039] Figure 1c , Figure 1d They are respectively the internal structure diagrams of a vertical micro-capacitive flexible mechanical sensor that can be applied and has a fingerprint-like "vortex" micro-nano structure in a typical embodiment of the present invention;

[0040] Figure 1e , Figure 1f , Figure 1g , Figure 1h They are respectively electron microscope images of a double helical micro-nanostructure of a vertical micro-capacitive flexible mechanical sensor with a fingerprint-like "vortex" micro-nanostructure that can be applied in a typical embodiment of the present invention;

[0041] Figure 1iIt is a schematic structural diagram of a vertical micro-capacitive flexible mechanical sensor that can be applied and has a fingerprint-like "vortex" micro-nano structure in a typical embodiment of the present invention;

[0042] Figure 2 It is a performance diagram of the selective response of a vertical micro-capacitive flexible mechanical sensor with a fingerprint-like "vortex" micro-nano structure to pressure, static friction, and sliding friction in a typical embodiment of the present invention;

[0043] Figure 3a , Figure 3b , Figure 3c They are respectively the actual application performance diagrams of a vertical micro-capacitive flexible mechanical sensor with a fingerprint-like "vortex" micro-nano structure that can be applied in a typical embodiment of the present invention and accurately senses pressure, static friction, and sliding friction;

[0044] Figure 4 It is an actual optical photograph of a tactile nerve pulse signal circuit system in a typical embodiment of the present invention and a library diagram of its design materials;

[0045] Figure 5a , Figure 5b They are respectively diagrams of pulse signal results after conversion by a tactile nerve pulse signal circuit system in a typical implementation scheme of the present invention. DETAILED DESCRIPTION

[0046] In view of the deficiencies in the prior art, the inventor of this case, after long-term research and extensive practice, was able to propose the technical solution of the present invention.

[0047] The inventors of this application have discovered through long-term research and extensive practice that the ability of natural human hands to correctly realize the key basic sensory functions of bearing objects (pressure) and sensing whether objects are grasped (dynamic friction) or held firmly (static friction) on the fingers may be due to the selective performance response of the "vortex" texture micro-nanostructure of the fingers to pressure and shear force. This simple, elegant but powerful natural micro-nanostructure design is the perfect bionic object for flexible sensors to pursue ultimate performance for prosthetic hands or robot bionic electronic skin functions that are committed to realizing humanoid functions. Inspired by this, the inventors of this application were able to propose the technical solution of the present invention.

[0048] The technical solution, its implementation process and principle will be further explained as follows.

[0049] See also Figure 1i According to one aspect of the present invention, a vertical micro-capacitive flexible mechanical sensor can be applied, which includes a flexible substrate 10, a sensitive layer and at least two electrodes 21, wherein the sensitive layer is arranged on the surface of the flexible substrate 10, and the at least two electrodes 21 are arranged on the sensitive layer at intervals;

[0050] Among them, the sensitive layer includes a capacitor micro-electrode plate 11 arranged on the surface of a flexible substrate 10 and a nanowire conductive network layer 20 arranged on the surface of the capacitor micro-electrode plate, the capacitor micro-electrode plate 11 includes a first capacitor micro-electrode plate and a second capacitor micro-electrode plate having a first spiral structure and a second spiral structure respectively, the first spiral structure and the second spiral structure cooperate to form a three-dimensional double-helical micro-nano structure imitating a fingerprint vortex, and a polymer dielectric layer 30 is also distributed between the first capacitor micro-electrode plate and the second capacitor micro-electrode plate; and the flexible substrate 10, the sensitive layer and the polymer dielectric layer 30 are combined into one, and the nanowire conductive network layer 20 forms a continuous integrated interface structure with the surface of the capacitor micro-electrode plate 11.

[0051] Specifically, the electrode 21 is an electrode wire, one end of which is electrically connected to the nanowire conductive network layer 20 , and the other end of which is led out from the surface of the nanowire conductive network layer 20 .

[0052] Specifically, the attachable vertical micro-capacitive flexible mechanical sensor further includes a packaging layer 40 for packaging the flexible mechanical sensor. The material and thickness of the packaging layer 40 can be existing known materials, and the thickness is set according to design requirements.

[0053] Specifically, the capacitor micro-electrode plate 11 and the flexible substrate 10 are integrally formed. It can be understood that the capacitor micro-electrode plate is a three-dimensional vertical micro-nano structure formed on the surface of the flexible substrate, that is, the flexible substrate is a flexible substrate with a microstructure, wherein the height of the first capacitor micro-electrode plate and the second capacitor micro-electrode plate is 10 to 50 μm, the width is 5 to 20 μm, the number of spiral turns is 10 to 50 turns, and the distance between the first capacitor micro-electrode plate and the second capacitor micro-electrode plate is greater than 30 μm and less than or equal to 100 μm; the thickness of the flexible substrate is 20-300 μm.

[0054] Specifically, the nanowire conductive network layer 20 includes a metal nanowire three-dimensional network conductive film having a three-dimensional mesh interconnected structure formed by a plurality of metal nanowires interwoven with each other, wherein the metal nanowires include any one or a combination of two or more of silver nanowires, copper nanowires, gold nanowires, and nickel nanowires, but not limited thereto; the thickness of the metal nanowire three-dimensional network conductive film is 2 to 10 μm

[0055] Specifically, the material of the polymer dielectric layer 30 includes any one or a combination of two or more of thermoplastic elastomer, polyvinyl alcohol, polydimethylsiloxane, and polyimide, but is not limited thereto.

[0056] The attachable capacitive flexible mechanical sensor provided by the embodiment of the present invention can form a compression, bending or tensile deformation state in the double-helix capacitive micro-electrode plate when working, so that the capacitive flexible mechanical sensor can form a selective identification response function of a fingerprint-like "vortex" three-dimensional double-helix micro-nano structure to pressure and shear force (i.e. static friction and sliding friction).

[0057] In addition, based on the fact that the attachable vertical micro-capacitive flexible mechanical sensor provided in the embodiment of the present invention can distinguish different mechanical types, the response signal can be converted into a corresponding characteristic frequency signal through circuit conversion, so that it corresponds to the neural signal of the action perception area such as grasping / gripping of the human hand, so as to realize human-computer interface interaction.

[0058] Correspondingly, an embodiment of the present invention also provides a tactile nerve pulse signal circuit system, which includes: the above-mentioned attachable vertical micro-capacitive flexible mechanical sensor, and a functional circuit for connecting with the above-mentioned attachable vertical micro-capacitive flexible mechanical sensor to form a signal conversion.

[0059] Furthermore, the attachable vertical micro-capacitive flexible mechanical sensor and the functional circuit are also connected to a power source to form a working circuit.

[0060] The embodiment of the present invention provides a method for manufacturing an attachable vertical micro-capacitive flexible mechanical sensor, which specifically includes the following steps:

[0061] S1 uses a mask plate plus photolithography technology to make a silicon template with a double spiral groove structure (i.e., the aforementioned patterned groove, the same below), and then fixes the silicon template on a hot plate and heats it at a constant temperature of 55-85°C, sprays a 1-10% metal nanowire ethanol solution on the surface of the silicon template with a double spiral groove structure, and heats it so that the ethanol evaporates immediately, and the remaining metal nanowires form a metal nanowire three-dimensional network conductive film on the surface of the silicon template with a double spiral groove structure, and the thickness of the metal nanowire three-dimensional network conductive film is 2-10μm; wherein, the double spiral groove structure includes a first groove and a second groove having a first spiral structure and a second spiral structure respectively, and the first spiral structure and the second spiral structure cooperate to form a three-dimensional double spiral micro-nano structure imitating a fingerprint vortex; the depth of the first groove and the second groove is 10- 50μm, a width of 5 to 20μm, a spiral number of 10 to 50 turns, and a distance between the first groove and the second groove is greater than 30μm and less than or equal to 100μm; wherein the metal nanowire can be any one of silver nanowire, copper nanowire, gold nanowire, and nickel nanowire, or a combination of two or more thereof;

[0062] S2: mechanically peeling off the metal nanowire three-dimensional network conductive film in the area other than the double-helix groove structure on the surface of the silicon template, leaving only the metal nanowire three-dimensional network conductive film on the inner wall and bottom of the double-helix groove structure, and the metal nanowire three-dimensional network conductive film remaining in the first groove and the second groove respectively forms a nanowire conductive network layer;

[0063] S3 spin-coats the flexible substrate material prepolymer onto the surface of the silicon template, and heats it at 60-85°C for 1-3h to solidify the flexible substrate material prepolymer to form a flexible substrate, and then peels the flexible substrate from the silicon template to obtain a flexible substrate with a three-dimensional double-helix micro-nano structure capacitor micro-electrode plate that mimics the "vortex" micro-nano structure. The structure is as follows Figure 1c , Figure 1d As shown; wherein, a nanowire conductive network layer is formed on the surface of a capacitor microplate to construct a sensitive layer, and the capacitor microplate comprises a first capacitor microplate and a second capacitor microplate having a first spiral structure and a second spiral structure respectively, the height of the first capacitor microplate and the second capacitor microplate is 10 to 50 μm, the width is 5 to 20 μm, the number of spiral turns is 10 to 50 turns, and the distance between the first capacitor microplate and the second capacitor microplate is greater than 30 μm and less than or equal to 100 μm; the thickness of the flexible substrate is 20-300 μm; the flexible substrate and the first capacitor microplate and the second capacitor microplate are an integral structure formed by a single complex; the material of the flexible substrate and the capacitor microplate can be any one or a combination of two or more of polyvinyl alcohol, polydimethylsiloxane, polydimethylsiloxane, polyethylene terephthalate, polyimide and polyethylene;

[0064] S4 spin-coats the polymer dielectric layer material onto the surface of the flexible substrate with the three-dimensional double-helix micro-nanostructure capacitor micro-electrode, and places it in an oven at a constant temperature of 35 to 65°C for 1 to 3 hours for curing, thereby forming a polymer dielectric layer. The polymer dielectric layer forms a continuous integrated interface structure with the metal nanowire three-dimensional network conductive film and the flexible substrate, so that all parties are integrated into one structure; its structure is as follows Figure 1e , Figure 1f , 1g , Figure 1h As shown, the polymer dielectric layer material is any one or a combination of two or more of thermoplastic elastomer (TPE), polyvinyl alcohol, polydimethylsiloxane, and polyimide;

[0065] S5: electrode wires are led out from the ends of the nanowire conductive network layer of the device prepared in step S4; the electrode wires and the nanowire conductive network layer are bonded with conductive silver paste, and then a flexible mechanical sensor with a complete "vortex" micro-nano structure is obtained, such as Figure 1a , Figure 1bAs shown; the capacitive flexible mechanical sensor formed by the above-mentioned manufacturing method has a selective response capability to pressure, static friction, and sliding friction. Figure 2 As shown in the figure, the capacitive flexible mechanical sensor with fingerprint-like "vortex" micro-nano structure can accurately sense pressure, static friction, and sliding friction. The actual application performance diagrams are shown in Figure 2. Figure 3a , Figure 3b , Figure 3c shown.

[0066] Example 1

[0067] 1) A silicon template having a double helix groove structure prepared by masking, photolithography and etching processing methods was ultrasonically cleaned with deionized water and ethanol / acetone for three times each and then dried, wherein the size of the double helix structure was 25 μm in depth and 15 μm in width, the distance between the spiral grooves was 70 μm, and the number of spiral turns was 30;

[0068] 2) The dried silicon template is fixed on a heating plate and maintained at a heating temperature of 85° C., and then a 1.5% silver nanowire / ethanol dispersion is sprayed on the template surface. After the ethanol evaporates, a layer of silver nanowire three-dimensional network structure conductive film is formed on the surface of the silicon template. Then, the silver nanowires outside the double helix groove are removed by mechanical stripping, leaving only the inner side wall and bottom silver nanowire conductive film of the double helix groove structure as the nanowire conductive network layer;

[0069] 3) Then, a polydimethylsiloxane (PDMS) prepolymer is spin-coated on the silicon template, and after being heated and cured in an oven at 80° C. for 2 hours, the cured PDMS is peeled off from the surface of the silicon template to prepare a flexible substrate having a silver nanowire three-dimensional network structure conductive film and a three-dimensional double-helical micro-nano structure capacitor micro-electrode plate having a "vortex" micro-nano structure, wherein the silver nanowire three-dimensional network structure conductive film is arranged on the surface of the capacitor micro-electrode plate to form a sensitive layer;

[0070] 4) After two electrodes are drawn out on the surface of the silver nanowire three-dimensional network structure conductive film, the flexible substrate with electrodes and sensitive layer is fixed on a spin coater, and a thermoplastic elastomer (TPE) / cyclohexane dispersion is spin-coated on the substrate and cured at room temperature for 3-4 hours to prepare a vertical micro-capacitive flexible mechanical sensor with a fingerprint-like "vortex" micro-nano structure.

[0071] The assembled flexible mechanical sensor was tested for its response performance to different force types. The test results are as follows: Figure 2 As shown in FIG. 1 , it is shown that the flexible device has the ability to selectively respond to pressure, static friction, and sliding friction. When the device is applied to a finger, it can respond to grasping an object or the sliding of an object. The flexible sensor is connected to a back-end signal processing circuit (such as Figure 4As shown), the power supply is connected to construct a tactile nerve pulse signal circuit system, and then the sensor output voltage telephone signal is converted into a pulse signal with frequency characteristics. The pulse signal result after conversion by the tactile nerve pulse signal circuit system is as follows Figure 5a , Figure 5b shown.

[0072] Comparative Example 1

[0073] The manufacturing method of a capacitive flexible mechanical sensor in this comparative example is basically the same as the method flow in Example 1, that is,

[0074] Under the same conditions as in Example 1, the metal nanowires of the nanowire conductive network layer used to construct the sensitive layer are replaced by ordinary conductive materials to construct a capacitive flexible mechanical sensor; and a performance test is performed on the capacitor: the capacitor constructed based on the control example 1 will not be resistant to stress and strain, that is, under pressure and shear force, the ordinary conductive material will break or fall off from the surface of the micro-nano structure (i.e., the capacitor micro-plate) because it does not have the flexibility of the metal nanowire conductive network, causing device failure or poor cycle performance (the device fails after 1-3 times), while the cycle stability of the metal nanowire conductive network in Example 1 can reach more than 100 times.

[0075] The embodiment of the present invention provides a three-dimensional double-helix micro-nano structure that can be applied to a vertical micro-capacitive flexible mechanical sensor and can achieve the selective response of the constructed device to pressure and shear force, thereby achieving the distinction of mechanical signals, for example: Figure 2 It can be clearly seen that the device has no response to pressure, the response value to static friction becomes larger, and the response value to sliding friction becomes smaller, so the type of force can be determined according to the positive and negative values ​​of the response; if other fork finger structures are used, basically all forces (pressure, shear force) have the same response trend (all upward or downward), which makes the device unable to distinguish force signals; and for the research background in the application, the prosthetic hand needs to be able to distinguish between pressure and shear force to distinguish whether the grasped object is grasped or dropped.

[0076] Compared with the prior art, the present invention uses a micro-nanostructure that imitates the "vortex" of human fingerprints to accurately sense the position and pattern of an object, constructs a vertical micro-capacitive structure flexible mechanical sensor with a double-helical micro-nanostructure electrode plate, and establishes a theoretical mechanism for the deformation response mode of the spiral micro-nanostructure under radial vertical pressure, tangential static friction and sliding friction. Without the need for complex signal analysis or algorithms, the single bionic micro-nanostructure flexible mechanical sensor can accurately sense and identify pressure, static friction and sliding friction. In addition, the embodiment of the present invention provides an attachable capacitive flexible mechanical sensor that is thin and soft, can be processed into a variety of shapes, and has the advantages of being wearable and attachable, especially the electrode plate therein adopts a fingerprint-imitation The "vortex" micro-nano structure can achieve selective response to pressure and shear force with high sensitivity, and also has the advantages of high precision, high reliability, long life, etc.; in addition, the preparation process of the attachable vertical micro-capacitive flexible mechanical sensor provided by the embodiment of the present invention is simple and controllable, and the raw materials are cheap and easy to obtain, which is suitable for large-scale industrial production; and the embodiment of the present invention also constructs a tactile nerve pulse signal circuit system, which realizes the conversion of different sensor response signals into specific pulse frequency electrical signals through circuit signal processing, so as to meet the requirements of matching with nerve pulse signals, provide a powerful method for further integration of perception signals and human physiological signals, and provide a signal basis for human-machine interface interaction and control, completing the ultra-sensitive perception realm of "human-device" fusion of bionic prostheses.

[0077] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A vertical micro-capacitive flexible mechanical sensor that can be attached, characterized in that It comprises a flexible substrate, a sensitive layer and at least two electrodes, wherein the sensitive layer is arranged on the surface of the flexible substrate, and the at least two electrodes are arranged on the sensitive layer at intervals; The sensitive layer includes a capacitor micro-electrode plate arranged on the surface of the flexible substrate and a nanowire conductive network layer arranged on the surface of the capacitor micro-electrode plate, the capacitor micro-electrode plate includes a first capacitor micro-electrode plate and a second capacitor micro-electrode plate having a first spiral structure and a second spiral structure respectively, the first spiral structure and the second spiral structure cooperate to form a three-dimensional double-helical micro-nano structure imitating a fingerprint vortex, and a polymer dielectric layer is also distributed between the first capacitor micro-electrode plate and the second capacitor micro-electrode plate; The attachable vertical micro-capacitive flexible mechanical sensor is manufactured by the following method: A template having a patterned groove on its surface is provided, wherein the patterned groove comprises a first groove and a second groove having a first spiral structure and a second spiral structure respectively, wherein the first spiral structure and the second spiral structure cooperate to form a three-dimensional double-spiral micro-nano structure imitating a fingerprint vortex pattern; Applying a metal nanowire dispersion with a solubility of 1-10 wt % on the surface of the template, and then drying to form a metal nanowire three-dimensional network conductive film with a three-dimensional mesh interconnected structure; The metal nanowire three-dimensional network conductive film in the area other than the patterned groove on the surface of the template is removed by mechanical stripping, and the metal nanowire three-dimensional network conductive film in the first groove and the second groove is retained, so that the metal nanowire three-dimensional network conductive film remaining in the first groove and the second groove serves as a nanowire conductive network layer; A prepolymer for forming a capacitor micro-electrode plate and a flexible substrate is coated on the surface of the template, and then the prepolymer is cured to form a capacitor micro-electrode plate and a flexible substrate, and the flexible substrate, the capacitor micro-electrode plate and the nanowire conductive network layer that are combined with each other are separated from the template, wherein the capacitor micro-electrode plate is integrally formed on the surface of the flexible substrate, and the nanowire conductive network layer is arranged on the surface of the capacitor micro-electrode plate to construct a sensitive layer, and the capacitor micro-electrode plate includes a first capacitor micro-electrode plate and a second capacitor micro-electrode plate having a first spiral structure and a second spiral structure respectively, and the first spiral structure and the second spiral structure cooperate to form a three-dimensional double-helical micro-nano structure imitating a fingerprint vortex; A polymer dielectric material is filled at least between the first capacitor micro-electrode plate and the second capacitor micro-electrode plate to form a polymer dielectric layer.

2. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The first capacitor microplate and the second capacitor microplate have a height of 10-50 μm, a width of 5-20 μm, a spiral number of 10-50 turns, and a spacing between the first capacitor microplate and the second capacitor microplate is greater than 30 μm and less than or equal to 100 μm.

3. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The nanowire conductive network layer comprises a metal nanowire three-dimensional network conductive film having a three-dimensional mesh interconnected structure formed by a plurality of metal nanowires interweaving with each other.

4. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 3 is characterized in that: The metal nanowires include any one of silver nanowires, copper nanowires, gold nanowires, and nickel nanowires, or a combination of two or more thereof.

5. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 3 is characterized in that: The thickness of the metal nanowire three-dimensional network conductive film is 2-10 μm.

6. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The flexible substrate, the sensitive layer and the polymer medium layer are integrated into one.

7. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The electrode is an electrode wire, one end of which is electrically connected to the nanowire conductive network layer, and the other end of which is led out from the surface of the nanowire conductive network layer.

8. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The material of the polymer dielectric layer includes any one or a combination of two or more of thermoplastic elastomer, polyvinyl alcohol, polydimethylsiloxane, and polyimide.

9. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The material of the flexible substrate includes any one or a combination of two or more of polyvinyl alcohol, polydimethylsiloxane, polydimethylsiloxane, polyethylene terephthalate, polyimide and polyethylene.

10. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The capacitor micro-electrode plate and the flexible substrate are integrally formed.

11. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The thickness of the flexible substrate is 20-300 μm.

12. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The material of the capacitor micro-electrode plate includes any one or a combination of two or more of polyvinyl alcohol, polydimethylsiloxane, polydimethylsiloxane, polyethylene terephthalate, polyimide and polyethylene.

13. The attachable vertical micro-capacitive flexible mechanical sensor according to claim 1, characterized in that: The thickness of the capacitive flexible mechanical sensor is 190-500 μm.

14. The method for manufacturing an attachable vertical micro-capacitive flexible mechanical sensor according to any one of claims 1 to 13, characterized in that include: A template having a patterned groove on its surface is provided, wherein the patterned groove comprises a first groove and a second groove having a first spiral structure and a second spiral structure respectively, wherein the first spiral structure and the second spiral structure cooperate to form a three-dimensional double-spiral micro-nano structure imitating a fingerprint vortex pattern; Applying a metal nanowire dispersion on the surface of the template to form a metal nanowire three-dimensional network conductive film; Removing the metal nanowire three-dimensional network conductive film in the area other than the patterned groove on the surface of the template, so that the metal nanowire three-dimensional network conductive film remaining in the first groove and the second groove serves as a nanowire conductive network layer; A prepolymer for forming a capacitor micro-electrode plate and a flexible substrate is coated on the surface of the template, and then the prepolymer is cured to form a capacitor micro-electrode plate and a flexible substrate, and the flexible substrate, the capacitor micro-electrode plate and the nanowire conductive network layer that are combined with each other are separated from the template, wherein the capacitor micro-electrode plate is integrally formed on the surface of the flexible substrate, and the nanowire conductive network layer is arranged on the surface of the capacitor micro-electrode plate to construct a sensitive layer, and the capacitor micro-electrode plate includes a first capacitor micro-electrode plate and a second capacitor micro-electrode plate having a first spiral structure and a second spiral structure respectively, and the first spiral structure and the second spiral structure cooperate to form a three-dimensional double-helical micro-nano structure imitating a fingerprint vortex; A polymer dielectric material is filled at least between the first capacitor micro-electrode plate and the second capacitor micro-electrode plate to form a polymer dielectric layer.

15. The method according to claim 14, characterized in that Specifically include: A metal nanowire dispersion with a solubility of 1-10wt% is coated on the surface of the template, and then dried to form a metal nanowire three-dimensional network conductive film with a three-dimensional mesh interconnected structure.

16. The method according to claim 14, characterized in that Specifically, the method includes: removing the metal nanowire three-dimensional network conductive film in the area other than the patterned groove on the surface of the template by mechanical stripping, and retaining the metal nanowire three-dimensional network conductive film in the first groove and the second groove.

17. The method according to claim 14, characterized in that Specifically include: A polymer dielectric material is coated on the surface of the flexible substrate with the sensitive layer bonded thereon, and then cured to form a polymer dielectric layer.

18. The method according to claim 14, characterized in that The method also includes: electrically combining the nanowire conductive network layer on the surface of the first electrode plate and the second electrode plate with one end of at least one electrode wire respectively, and leading the other end of the electrode wire out from the surface of the nanowire conductive network layer.

19. The method according to claim 14, characterized in that: The first groove and the second groove have a depth of 10-50 μm, a width of 5-20 μm, a number of spiral turns of 10-50, and a distance between the first groove and the second groove is greater than 30 μm and less than or equal to 100 μm.

20. A tactile nerve pulse signal circuit system, characterized in that include: An attachable vertical micro-capacitive flexible mechanical sensor as described in any one of claims 1 to 13, and a functional circuit for connecting with the capacitive flexible mechanical sensor to form a signal conversion.

21. The tactile nerve pulse signal circuit system according to claim 20, characterized in that: The attachable vertical micro-capacitive flexible mechanical sensor and the functional circuit are also connected to a power source to form a working loop.

Images