Flexible electrode, sensor and preparation method of flexible electrode

Abstract

The invention provides a flexible sensing element, a sensor and a preparation method of the flexible sensing element. The flexible sensing element comprises two layers of oppositely arranged flexible substrates and a sensing layer formed between the two layers of flexible substrates; wherein the sensing layer comprises an electrode pattern imitating a circular spider net structure and external connection pieces symmetrically arranged on the two sides of the electrode pattern, and the two external connection pieces are both in conductive connection with the electrode pattern; comprising a radial framework and a plurality of concentric loop lines which are outwards arranged on the framework at intervals in the radiation direction, and the loop lines are conductively connected with the framework. The sensing layer of the flexible sensing element provided by the invention has the electrode pattern imitating the circular spider net-shaped structure, and the electrode pattern is the centrosymmetric pattern and can sense tiny external force changes in any direction, so that the magnitude and direction of an acting force applied when a cotton stalk is pulled up can be accurately sensed.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a flexible electrode, a sensor, and a method for fabricating the flexible electrode. Background Technology

[0002] Against the backdrop of modern agricultural development, intelligent sensing technology is driving the transformation of my country's traditional agriculture towards intelligence and informatization. After cotton harvesting, cotton stalks need to be removed, and accurately obtaining the magnitude and direction of the force applied during stalk removal is a key factor in the design of cotton stalk removal equipment. Traditional methods using rigid sensors to collect the force applied during stalk removal generally only capture the upward force and cannot capture forces in other directions to achieve omnidirectional sensing. This results in cotton stalk removal equipment designed based on this method having problems such as high stalk breakage rate and inability to remove stalks completely. Summary of the Invention

[0003] The purpose of this invention is to provide a flexible electrode, a sensor, and a method for preparing the flexible electrode. The flexible electrode has multiple conduction paths when subjected to deformation, which increases the sensitivity to minute changes and is suitable for omnidirectional sensing of stress state when cotton stalks are pulled out in their entirety.

[0004] To achieve the above objectives, in a first aspect, embodiments of this application provide a flexible sensing element, comprising two opposing flexible substrates and a sensing layer formed between the two flexible substrates; wherein...

[0005] The sensing layer includes an electrode pattern with a semi-circular spider web structure and external connectors symmetrically arranged on both sides of the electrode pattern. Both external connectors are electrically connected to the electrode pattern. The electrode pattern is a centrally symmetrical graphic, including a radial skeleton and multiple concentric rings arranged at intervals along the radial direction on the skeleton. The rings are electrically connected to the skeleton.

[0006] Furthermore, the skeleton includes multiple radial lines radiating outward from the pole, with the included angle between two adjacent radial lines being equal.

[0007] Furthermore, the two external connectors are respectively connected to the extended ends of the two coaxially arranged radial lines.

[0008] Furthermore, the flexible substrate is formed by curing TPU colloid.

[0009] Furthermore, the external component includes a connecting portion and a wire connected to the connecting portion, the connecting portion being electrically connected to the electrode pattern.

[0010] Furthermore, the connection portion is formed by curing conductive silver paste.

[0011] Secondly, embodiments of this application also provide a sensor, including a strain detection circuit and a signal processing circuit; wherein,

[0012] The strain detection circuit includes a voltage divider circuit consisting of a flexible sensing element and a fixed resistor with a fixed resistance value connected in series. The flexible sensing element is as described in the first aspect, and the fixed resistor is connected to one of the external components of the flexible sensing element.

[0013] The signal processing circuit includes a signal acquisition module and a data processing module connected to the output terminal of the signal acquisition module. The input terminal of the signal acquisition module is electrically connected to the output terminal of the voltage divider circuit to obtain the voltage divider signal output by the voltage divider circuit.

[0014] The signal acquisition module is configured to acquire the analog voltage signal output by the voltage divider circuit, convert the analog voltage signal into a digital voltage signal, and then send it to the data processing module.

[0015] The data processing module is configured to determine the strain change value of the flexible sensing element based on the voltage digital signal, and to determine the external force on the flexible sensing element based on the strain change value.

[0016] Thirdly, embodiments of this application also provide a method for fabricating a flexible sensing element, the method being used to fabricate the flexible sensing element as described in the first aspect, the method comprising:

[0017] Preparation of flexible substrates;

[0018] An electrode pattern is formed on one side surface of the flexible substrate;

[0019] Symmetrically arranged external components are formed on both sides of the electrode pattern.

[0020] Furthermore, the preparation of the flexible substrate includes:

[0021] TPU colloid is uniformly coated onto a smooth glass substrate surface to form a uniform coating.

[0022] The coated glass substrate is dried and cured under negative pressure to form a flexible substrate.

[0023] Furthermore, an electrode pattern is formed on one side surface of the flexible substrate, including:

[0024] Electrode patterns are screen-printed on one side surface of the flexible substrate;

[0025] The electrode pattern is cured to form a stable electrode pattern on the surface of the flexible substrate.

[0026] The beneficial effects of this invention are reflected in:

[0027] The sensing layer of the flexible sensing element provided in this application has an electrode pattern with a circular spider web-like structure and the electrode pattern is a centrally symmetrical figure. It can sense minute changes in external force in any direction, thereby accurately sensing the magnitude and direction of the force applied when the cotton stalk is pulled up.

[0028] The sensor provided in this application has the aforementioned flexible sensing element, and therefore also has the technical effect of the flexible sensing element, which can accurately obtain the magnitude and direction of the force applied when the cotton stalk is pulled up. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Other drawings will be readily available to those skilled in the art based on these drawings without any inventive effort.

[0031] Figure 1 This is a schematic diagram of the structure of the flexible sensing element provided in an embodiment of the present invention;

[0032] Figure 2 A schematic diagram of the structure of the sensing layer formed on a flexible substrate according to an embodiment of the present invention;

[0033] Figure 3 A schematic diagram of the electrode pattern provided in an embodiment of the present invention. Figure 1 ;

[0034] Figure 4 A schematic diagram of the electrode pattern provided in an embodiment of the present invention. Figure 2 ;

[0035] Figure 5 This is an electrical structure block diagram of the sensor provided in an embodiment of the present invention;

[0036] Figure 6 A circuit diagram of a voltage divider circuit provided in an embodiment of the present invention;

[0037] Figure 7 The results of the resistance response strain test curve of the flexible sensing element provided in the embodiments of the present invention;

[0038] Figure 8The sensitivity coefficient-strain relationship curve of the flexible sensing element provided in the embodiments of the present invention;

[0039] Figure 9 The present invention provides a dynamic cyclic response test curve of a flexible sensing element with the same amplitude but different frequencies.

[0040] Figure 10 This is a graph showing the change rate of resistance of a flexible sensing element with temperature, provided in an embodiment of the present invention.

[0041] Figure 11 Cyclic durability test curves of flexible sensing elements provided in embodiments of the present invention;

[0042] Figure 12 A schematic diagram of a flexible sensing element attached to the surface of a cotton stalk according to an embodiment of the present invention;

[0043] Figure 13 A graph showing the rate of change of resistance of a flexible sensing element during the pulling of cotton stalks, provided in an embodiment of the present invention.

[0044] Figure 14 This is a schematic diagram of the fabrication process of the flexible sensing element provided in an embodiment of the present invention.

[0045] The realization of the objectives, functional features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and textual descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0046] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0047] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by those skilled in the art to which this invention pertains.

[0048] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0049] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0050] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0052] After cotton harvesting, the cotton stalks need to be removed. Accurately determining the magnitude and direction of the force applied during stalk removal is a key factor in the design of stalk removal equipment. Force is a vector quantity with both magnitude and direction. Traditional methods using rigid sensors to collect the force applied during stalk removal typically only capture the upward force, failing to capture forces in other directions for omnidirectional sensing. This results in stalk removal equipment designed based on this method exhibiting problems such as high stalk breakage rates and inability to remove stalks intact.

[0053] In view of this, the embodiments of this application provide a flexible sensing element, a sensor, and a method for fabricating the flexible sensing element. The flexible sensing element and sensor can solve the above problems, and will be described in detail below.

[0054] Firstly, please refer to Figure 1 This application provides a flexible sensing element with a sandwich structure, comprising two opposing flexible substrates 1 and a sensing layer formed between the two flexible substrates 1. The sensing layer includes an electrode pattern 2 with a simulated circular spider web structure and external connectors symmetrically arranged on both sides of the electrode pattern 2, both of which are electrically connected to the electrode pattern 2.

[0055] Common flexible substrate materials include thermoplastic polyurethane (TPU), polydimethylsiloxane (PDMS), and Ecoflex silicone. In this embodiment, the flexible substrate 1 is formed by curing TPU colloid. TPU colloid was chosen to fabricate the flexible substrate 1 because it can be directly printed onto a pre-made film, simplifying the process and eliminating the need for additional curing agents. It is understood that flexible substrates can also be fabricated using substrate materials such as polydimethylsiloxane (PDMS) or Ecoflex silicone.

[0056] Spider webs in nature possess a unique neural sensing system, acting as a "natural sensor" to capture prey by sensing vibrations in their silk. This biological structure, through the synergistic effect of a radially symmetrical support frame and spirally arranged silk threads, exhibits uniformly distributed force characteristics in all directions. Spider webs possess multi-scale mechanical resonance sensing capabilities, and their mechanical response and signal conversion mechanisms provide a basis for the structural design of flexible sensing elements. Based on the uniformly distributed force characteristics of the spider web structure, the flexible sensing element of this application designs the electrode pattern 2 as a simulated circular spider web structure to ensure the uniformity of the mechanical response and to sense minute changes in external force in any direction.

[0057] Specifically, such as Figure 2 and Figure 3 As shown, electrode pattern 2 is a centrally symmetrical pattern. Specifically, electrode pattern 2 includes a radial framework 4 and multiple concentric rings 3 spaced outwards along the radial direction on the framework 4. The rings 3 are electrically connected to the framework 4. Specifically, the framework 4 includes multiple radial lines 5 radiating outwards from the pole. Each radial line 5 has a symmetrical counterpart in the opposite direction, and the included angle between adjacent radial lines 5 is equal. Because electrode pattern 2 is a centrally symmetrical pattern, the number of radial lines 5 is even, such as 4, 6, 8, etc. The more radial lines 5 and the more rings 3, the higher the accuracy of sensing changes in external force. In this embodiment, water-based conductive ink can be screen-printed onto one side of the flexible substrate 1, dried, and then deposited to form electrode pattern 2.

[0058] For example, such as Figure 4 As shown, this illustrates a specific structure of electrode pattern 2. The skeleton 4 of electrode pattern 2 includes six radial lines 5 radiating outward from the pole, and three ring lines 3. The width of electrode pattern 2 is 14.25 mm. The line width of the ring lines 3 and the width of the radial lines 5 are both 1 mm. The spacing between two adjacent ring lines 3 is 1 mm, and the angle between two adjacent radial lines 5 is 60°. From Figure 4 As can be seen, the line segment of the ring line 3 between two adjacent radial lines 5 is an arc segment. This arc segment is concave inward towards the direction of the radiation pole. The outer diameters of the three ring line segments between two adjacent radial lines 5 are 40mm, 38mm and 36mm respectively from the inside to the outside. The three ring line segments between two adjacent radial lines 5 are set with the same center.

[0059] Designing the loop 3 connecting two adjacent radial lines 5 as an arc segment allows for a larger deformation range compared to designing the loop 3 as a straight segment, thus reducing the risk of breakage during deformation. Of course, it's understandable that the loop 3 connecting two adjacent radial lines 5 could also be designed as an outward-convex arc structure moving away from the radiation poles. Alternatively, without considering the deformation range, the loop 3 connecting two adjacent radial lines 5 could also be designed as a straight segment.

[0060] It is understandable that the resistance value of the electrode pattern 2 in the flexible sensing element will change with strain. That is, the change in the resistance value of the electrode pattern 2 is related to the external force (including the magnitude and direction of the force) on the flexible sensing element. Based on this relationship, after obtaining the change in the resistance value of the electrode pattern 2, the external force on the flexible sensing element can be identified, thereby achieving the purpose of detecting the external force.

[0061] In this embodiment, to facilitate the subsequent fabrication of the sensing layer and ensure that the two external components are symmetrically arranged about both sides of the electrode pattern 2, the two external components are respectively connected to the extended ends of the two coaxially arranged radial lines 5. Since the electrode pattern 2 is a centrally symmetrical figure, the two ends of the two coaxially arranged radial lines 5 must be symmetrical. Therefore, directly connecting the two external components to the extended ends of the two coaxially arranged radial lines 5 can ensure that the two external components are symmetrical about the electrode pattern 2, thereby facilitating fabrication.

[0062] Continue to refer to Figure 2 and Figure 3 As shown, the extended ends of the radial wires 5 used for connecting to the two external components extend outward to form extensions 8. The external components can be directly connected to the extensions 8, which makes it convenient to electrically connect the external components to the corresponding radial wires 5 during the manufacturing process. Figure 4The length of the entire electrode pattern 2 shown is 22 mm.

[0063] It should be pointed out that, Figure 4 The specific structure and size parameters of the electrode pattern 2 shown are for illustrative purposes only and do not impose specific limitations on the structure and size of the electrode pattern 2.

[0064] For example, such as Figure 2 As shown, the external connector includes a connecting part 6 and a wire 7 connected to the connecting part 6. The connecting part 6 is electrically connected to the electrode pattern 2. Specifically, one end of the connecting part 6 is connected to the extension of the radial line 5, and the other end is connected to the wire 7, which is used to stably connect to the external circuit.

[0065] In this embodiment, the connecting part 6 is formed by curing conductive silver paste. The cured conductive silver paste forms a stable conductive network through silver powder particles, enabling reliable connection between electronic components. Its resistance value is controllable, meeting the precision requirements of microelectronic devices, and it features stable conductivity, high mechanical strength, and adaptability to complex processing.

[0066] In summary, the sensing layer of the flexible sensing element provided in this application embodiment has an electrode pattern with a circular spider web-like structure, and the electrode pattern is a centrally symmetrical figure, which can sense minute changes in external force in any direction, thereby accurately sensing the magnitude and direction of the force applied when the cotton stalk is pulled up.

[0067] Secondly, such as Figure 5 As shown in the illustration, this application also provides a sensor, which includes a strain detection circuit and a signal processing circuit. The strain detection circuit includes a flexible sensing element R... sensor A voltage divider circuit is formed by connecting a fixed resistor R1 in series with the resistor. The circuit structure of the voltage divider circuit is as follows: Figure 6 As shown, the structure of the flexible sensing element is as described in the first aspect, with the fixed resistor R1 and the flexible sensing element R sensor One of the external components is connected by a wire. The signal processing circuit includes a signal acquisition module and a data processing module connected to the output of the signal acquisition module. The input of the signal acquisition module is electrically connected to the output of the voltage divider circuit to obtain the voltage divider signal output from the voltage divider circuit.

[0068] In this embodiment, the signal acquisition module is configured to acquire the analog voltage signal output by the voltage divider circuit, convert the analog voltage signal into a digital voltage signal, and then send it to the data processing module. The data processing module is configured to determine the strain change value of the flexible sensing element based on the digital voltage signal, and determine the external force acting on the flexible sensing element based on the strain change value.

[0069] In actual implementation, the signal processing circuit mainly consists of three modules: a power management module, a signal acquisition module, and a data processing module. The power management module uses an AMS1117-3.3 voltage regulator chip to convert the external 5V voltage to the 3.3V required by the system, providing a stable, low-power supply. It also serves as the voltage divider reference voltage V in the strain detection circuit. cc .

[0070] The signal acquisition module is equipped with a 16-bit high-precision ADC (ADS1115) for high-precision acquisition of the voltage signals output by the flexible sensing element, and has four input channels. The ADS1115 converts these analog signals into digital signals, which are then transmitted to the ESP32-S3 microprocessor (actually a data processing module) via an I2C interface. The ESP32-S3 microprocessor then sends the sensing information to a host computer receiving terminal via a serial port for visualization. The microprocessor in the signal acquisition module can be an STC89C52 chip, an AVR chip, an ESP32 chip, or an Arduino chip, etc.

[0071] For example, the sampling frequency of the signal acquisition module is 100Hz. The wires of the flexible sensing element can be connected to the circuit via the DB301V-3.5-2P-GN-S terminal block. The resistance of the flexible sensing element changes with strain, thereby causing a corresponding change in the output voltage of the voltage divider circuit. Figure 6 In the voltage divider circuit structure shown, the output voltage of the voltage divider circuit is:

[0072]

[0073] In the formula, R1 is a fixed resistor with a value of 10kΩ; R sensor The resistance of the flexible sensing element; V cc V is the input voltage. out This is the output voltage of the voltage divider circuit.

[0074] Figure 7 and Figure 8 The test results of the relative resistance change of the sensor within the range of 0-12% are shown. The rate of change of the sensor's sensitivity (GF) increases linearly with increasing strain, verifying the positive correlation between sensitivity and strain. The formula for sensitivity (GF) is as follows:

[0075]

[0076] In the formula, GF represents the sensitivity coefficient of the sensor; ∆R represents the resistance change of the flexible sensing element under a certain strain, in kΩ; R0 represents the initial resistance of the flexible sensing element, in kΩ; and ε represents the strain of the flexible sensing element.

[0077] Figure 9 This paper demonstrates the use of a flexible sensing element fixed on an electronic universal testing machine, undergoing cyclic loading-unloading tests at different frequencies (0.5 Hz, 1 Hz, and 1.5 Hz) under the same strain conditions, and recording the changes in the resistance / strain response signal. From... Figure 9 It can be seen that the peak value of the output signal is stable and there is no significant difference, showing a high degree of consistency, indicating the stability of the flexible sensing element and sensor under different loading rates.

[0078] Considering that the performance of flexible sensing elements will be affected by ambient temperature fluctuations in actual field applications and under room temperature conditions, it is necessary to further study the temperature difference sensitivity of the fabricated flexible sensing elements. For example... Figure 10 As shown, the resistance of the sensor did not fluctuate significantly when ΔT ≈ 40℃, indicating that both the flexible sensing element and the sensor exhibit good dynamic stability under temperature fluctuations.

[0079] In long-term monitoring applications, its stability directly affects the accuracy and reliability of data collection. For example... Figure 11 As shown, the flexible sensing element underwent 100 cycles of testing at a strain of 10% and a tensile frequency of 0.5Hz. The signal output of the voltage divider circuit was recorded over time using a data acquisition system. It can be seen that the signal output of the flexible sensing element remained accurate and stable during the 100th cycle of testing.

[0080] In this embodiment, when the sensor is used to monitor force changes during the pulling process of cotton stalks, a suitable location is selected for installation. This location is free of pests, smooth, and without protruding nodules. The surface of the cotton stalk is cleaned with an alcohol swab and dried. The flexible sensing element is then placed between two layers of waterproof PU film and attached axially along the surface of the cotton stalk. After attachment, the area is left to stand for 10 minutes. A specific installation example is shown below. Figure 12 As shown.

[0081] Figure 13 The equation illustrates the changes in electrical signals and force values ​​output by the sensor during the cotton stalk pulling process. It can be divided into two stages: the rising pulling force stage, where the cotton stalk roots overcome the adhesion and friction between the roots and the soil to move upwards, reaching its maximum value when the main root and most lateral roots are completely broken; and the falling pulling force stage, where the pulling force reaches its maximum value at a certain moment and then rapidly decreases. This sensor can accurately capture the changing points during the pulling process.

[0082] In summary, because the strain detection circuit of this sensor uses the flexible sensing element as described in the first aspect as the detection electrode, the sensor can not only sense minute changes in external force in any direction, but also accurately sense the magnitude and direction of the force applied when the cotton stalk is pulled up. Furthermore, by using the flexible sensing element as described in the first aspect as the detection electrode, the sensor's sensing performance is unaffected by complex changes in the field environment, solving the problem of signal drift that can occur in complex field conditions.

[0083] Thirdly, such as Figure 14 As shown, this application also provides a method for fabricating a flexible sensing element, which is used to fabricate a flexible sensing element as described in the first aspect. The fabrication method includes the following steps:

[0084] Step S100: Prepare a flexible substrate.

[0085] Specifically, the TPU colloid is first applied evenly to a smooth glass substrate using a four-sided coating tool to achieve a uniform coating. The coated substrate is then placed in a vacuum oven at 50°C to accelerate the curing process, ultimately forming a TPU substrate with a thickness of 0.15 mm.

[0086] Step S200: Form an electrode pattern on one side surface of the flexible substrate.

[0087] Specifically, after customizing the desired pattern on the screen, a clean TPU substrate is placed on the printing table and fixed in place to prevent misalignment during printing. A 200-mesh screen is placed above the TPU substrate to ensure a tight bond between the two. An appropriate amount of water-based conductive ink is deposited on the screen. The thickness of the ink film can be adjusted by the printing pressure and squeegee angle. The squeegee is tilted at 45° and pushed to allow the ink to be evenly deposited through the pattern holes onto the surface of the TPU substrate, thus outlining the target pattern electrodes. The squeegee is applied with reciprocating pressure to ensure seamless transfer of the water-based conductive ink to the TPU substrate during the screen printing process. The printed pattern is then dried in a vacuum oven at 80°C for 20 minutes to increase the adhesion between the ink layer and the TPU substrate.

[0088] It should be noted that the thickness of the electrode pattern is related to the number of printings. Generally, it is printed twice during processing. The number of printings will also affect the change in the initial resistance of the electrode pattern. For example, it is 50KΩ after one printing and 100KΩ after two printings.

[0089] Step S300: Form symmetrically arranged external parts on both sides of the electrode pattern.

[0090] To achieve a stable connection between the electrode pattern and the external circuit, conductive silver paste is used to externally encapsulate the electrode pattern. The paste is then dried at room temperature for 1 hour to allow it to fully solidify and form the connection. This connection is then stably connected to the external circuit via wires.

[0091] Finally, the sensing layer on one side of the TPU substrate can be encapsulated again with TPU colloid. After drying the TPU colloid, a sandwich structure of TPU substrate-sensing layer-TPU substrate is formed, resulting in a complete flexible sensing element.

[0092] The flexible sensing element as described in the first aspect can be prepared using the preparation method provided in this embodiment. The process is simple, does not require additional curing agents, and is easy to operate.

[0093] Finally, it should be noted that the technical features of the technical solution of this application can be combined arbitrarily. In order to simplify the description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0094] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A flexible sensing element, characterized in that, It includes two opposing flexible substrates (1) and a sensing layer formed between the two flexible substrates (1); wherein, The sensing layer includes an electrode pattern (2) with a simulated circular spider web structure and external components symmetrically arranged on both sides of the electrode pattern (2). Both external components are electrically connected to the electrode pattern (2). The electrode pattern (2) is a centrally symmetrical pattern, including a radial skeleton (4) and multiple concentric ring lines (3) arranged at intervals along the radial direction on the skeleton (4). The ring lines (3) are electrically connected to the skeleton (4).

2. The flexible sensing element as described in claim 1, characterized in that, The skeleton (4) includes multiple radial lines (5) radiating outward from the pole, with the included angle between two adjacent radial lines (5) being equal.

3. The flexible sensing element as described in claim 2, characterized in that, The two external connectors are respectively connected to the extended ends of the two coaxially arranged radial lines (5).

4. The flexible sensing element as described in claim 1, characterized in that, The flexible substrate (1) is formed by curing TPU colloid.

5. A flexible sensing element as described in claim 1, characterized in that, The external connector includes a connecting part (6) and a wire (7) connected to the connecting part (6), the connecting part (6) being electrically connected to the electrode pattern (2).

6. A flexible sensing element as described in claim 5, characterized in that, The connecting part (6) is formed by curing conductive silver paste.

7. A sensor, characterized in that, It includes strain detection circuitry and signal processing circuitry; among which, The strain detection circuit includes a voltage divider circuit consisting of a flexible sensing element and a fixed resistor with a fixed resistance connected in series. The flexible sensing element is as described in any one of claims 1-6, and the fixed resistor is connected to one of the external components of the flexible sensing element. The signal processing circuit includes a signal acquisition module and a data processing module connected to the output terminal of the signal acquisition module. The input terminal of the signal acquisition module is electrically connected to the output terminal of the voltage divider circuit to obtain the voltage divider signal output by the voltage divider circuit. The signal acquisition module is configured to acquire the analog voltage signal output by the voltage divider circuit, convert the analog voltage signal into a digital voltage signal, and then send it to the data processing module. The data processing module is configured to determine the strain change value of the flexible sensing element based on the voltage digital signal, and to determine the external force on the flexible sensing element based on the strain change value.

8. A method for fabricating a flexible sensing element, characterized in that, The preparation method is used to prepare the flexible sensing element as described in any one of claims 1-6, and the preparation method includes: Preparation of flexible substrates; An electrode pattern is formed on one side surface of the flexible substrate; Symmetrically arranged external components are formed on both sides of the electrode pattern.

9. The method for fabricating a flexible sensing element as described in claim 8, characterized in that, The preparation of the flexible substrate includes: TPU colloid is uniformly coated onto a smooth glass substrate surface to form a uniform coating. The coated glass substrate is dried and cured under negative pressure to form a flexible substrate.

10. The method for fabricating a flexible sensing element as described in claim 8, characterized in that, An electrode pattern is formed on one side surface of the flexible substrate, including: Electrode patterns are screen-printed on one side surface of the flexible substrate; The electrode pattern is cured to form a stable electrode pattern on the surface of the flexible substrate.

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