A flexible sensor array and a method of manufacturing the same

Abstract

The application discloses a flexible sensor array and a preparation method thereof, relates to the technical field of flexible sensors, and discloses a flexible sensor array preparation method, which comprises the following steps: coating a slurry of a shape memory polymer on the surface of a target curved surface and solidifying to obtain a curved surface polymer; flattening the curved surface polymer when the curved surface polymer is in a high-elasticity state, and cooling to below a switching temperature of the shape memory polymer to obtain a planar polymer; printing each functional layer of the flexible sensor array on the planar polymer layer by layer through 3D printing technology; when each functional layer of the flexible sensor array is preliminarily solidified, heating to above the switching temperature, so that the planar polymer returns to the curved surface polymer, and each functional layer of the flexible sensor array is completely solidified, thereby obtaining the flexible sensor array. The application overcomes the internal stress interference of the flexible sensor array, and improves the sensor precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible sensor, in particular to a flexible sensor array and a preparation method thereof. BACKGROUND

[0002] Flexible sensors are sensors used to convert mechanical signals into electrical signals, and they play an important role in sensing and monitoring in environments with complex curved surfaces such as robots. In order to adapt to the complex curved surface of the robot surface, the flexible sensor and its array need to have high flexibility so as to closely fit the curved surface and achieve conformal contact, ensuring the clarity and accuracy of the signal. In order to improve this conformal ability, flexible sensors usually reduce their minimum bending radius by reducing the modulus or thickness of the material, so as to better adapt to the complex curved surface environment, and they usually exist in the form of thin films.

[0003] In the traditional preparation process, flexible sensors are usually manufactured on a flat surface, which makes them isotropic. However, when these sensors are transferred to a curved surface, due to the difference in curvature and height of the curved surface in different directions, the isotropic sensors may be stretched or compressed unevenly when fitted to the anisotropic curved surface. This uneven deformation can cause local stress concentration, which in turn generates internal stress. Internal stress not only reduces the measurement accuracy of the sensor, but also can cause the adhesion between the sensor and the curved surface to fail, forming a cavity. These cavities can introduce additional mechanical structures, interfering with the transmission of mechanical signals to the sensor, thereby generating error signals or noise.

[0004] The above content is only used to assist in understanding the technical solutions of the present application, and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0005] The main purpose of the present application is to provide a flexible sensor array and a preparation method thereof, which aims to overcome the problem of internal stress interference in the flexible sensor array.

[0006] To achieve the above-mentioned purpose, the present application provides a flexible sensor array preparation method, comprising the following steps:

[0007] Coating a slurry of shape memory polymer on the surface of the target curved surface and curing to obtain a curved polymer;

[0008] Flattening the curved polymer when it is in a high-elastic state, and cooling to below the switching temperature of the shape memory polymer to obtain a flat polymer;

[0009] Printing each functional layer of the flexible sensor array on the flat polymer layer by layer through 3D printing technology;

[0010] In the case that the functional layers of the flexible sensor array are preliminarily solidified, the temperature is raised to above the switching temperature, the planar polymer is returned to a curved polymer, and the functional layers of the flexible sensor array are completely solidified, to obtain the flexible sensor array.

[0011] In an embodiment, the step of flattening the curved polymer comprises:

[0012] The curved polymer is flattened by pulling and placed on a processing plane with a heat release tape, wherein the failure temperature of the heat release tape is lower than the switching temperature.

[0013] In an embodiment, the step of flattening the curved polymer by pulling comprises:

[0014] The edges of the curved polymer are fixed by an X-Y double-axis motion frame, and are pulled apart along the X-axis and the Y-axis respectively to be taut into a plane.

[0015] In an embodiment, the flexible sensor array comprises a plurality of sensing units, the functional layers of each sensing unit comprising a first electrode layer, a sensing layer and a second electrode layer, the first electrode layers of each sensing unit being connected by a first wire, and the second electrode layers of each sensing unit being connected by a second wire, and the step of printing the functional layers of the flexible sensor array on the planar polymer layer by layer by the 3D printing technology comprises:

[0016] The first electrode layer and the first wire are printed on the planar polymer in the same horizontal plane by the 3D printing technology;

[0017] The sensing layer is printed on the planar polymer by the 3D printing technology;

[0018] The second electrode layer and the second wire are printed on the planar polymer in the same horizontal plane by the 3D printing technology.

[0019] In an embodiment, the functional layers of the flexible sensor array further comprise a first support layer, a second support layer and a third support layer, and the step of printing the functional layers of the flexible sensor array on the planar polymer layer by layer by the 3D printing technology comprises:

[0020] The first support layer is printed on a preset first support area of the planar polymer by the 3D printing technology, wherein the first support area is in the same horizontal plane as the first electrode layer and the first wire, and vertically overlaps the corresponding area of the second wire;

[0021] The second support layer is printed on the second support area pre-set on the planar polymer by 3D printing technology, wherein the second support area is in the same horizontal plane with the sensing layer and vertically overlaps with the corresponding area of the first conducting wire and the second conducting wire;

[0022] The third support layer is printed on the third support area pre-set on the planar polymer by 3D printing technology, wherein the third support area is in the same horizontal plane with the second electrode layer and the second conducting wire and vertically overlaps with the corresponding area of the first conducting wire.

[0023] In an embodiment, the switching temperature is 30-50℃.

[0024] The embodiments of the present application also provide a flexible sensor array, which is prepared by the above method.

[0025] In an embodiment, the flexible sensor array comprises a plurality of sensing units connected by conducting wires, and the functional layer of each sensing unit comprises a first electrode layer, a sensing layer and a second electrode layer arranged vertically.

[0026] In an embodiment, the first electrode layers of each sensing unit are connected by the first conducting wires, and the second electrode layers of each sensing unit are connected by the second conducting wires, and the first conducting wires and the second conducting wires are arranged in a row-column cross arrangement.

[0027] In an embodiment, the first electrode layer and the first conducting wire are made of the same material, and the second electrode layer and the second conducting wire are made of the same material.

[0028] The one or more technical solutions provided in the application have at least the following technical effects: a flexible sensor array preparation method is provided, a curved surface polymer is obtained by coating a slurry of a shape memory polymer on the surface of a target curved surface and solidifying, then the curved surface polymer is flattened and cooled to below the switching temperature of the shape memory polymer in a high-elastic state to obtain a planar polymer, then each functional layer of the flexible sensor array is printed layer by layer on the planar polymer by 3D printing technology, then the planar polymer is restored to a curved surface polymer by heating to above the switching temperature when each functional layer of the flexible sensor array is preliminarily solidified, and each functional layer of the flexible sensor array is completely solidified, to obtain the flexible sensor array. The embodiments of the application utilize the characteristics of the shape memory polymer that can be restored in a high-elastic state after being deformed in a glass state, first copy the target curved surface shape with the shape memory polymer, and then flatten the polymer after further cooling to the glass state, so that the curved surface preparation process of the flexible sensor array is converted into a mature controllable planar preparation process. Then, combined with the 3D printing technology, different functional layers of the flexible sensor array are continuously printed, the stress interference caused by the assembly process is reduced, and the preparation of a highly personalized sensor array structure on the shape memory polymer is realized. After constructing each functional layer of the sensor array, the shape polymer is triggered to restore by heating, so that the sensor array is driven to deform in the restoration of the shape memory polymer, and is restored to a stress-free state close to the curved surface, thereby effectively overcoming the internal stress interference of the flexible sensor array and improving the accuracy of the prepared sensor. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 A flowchart of the flexible sensor array preparation method related to the embodiments of the application is shown.

[0030] Figure 2 A structure diagram of the flexible sensor array related to the embodiments of the application is shown. Figure One ;

[0031] Figure 3 A structure diagram of the flexible sensor array related to the embodiments of the application is shown. Figure Two ;

[0032] Figure 4 A structure diagram of the flexible sensor array related to the embodiments of the application is shown. Figure Three ;

[0033] Figure 5 A structure diagram of the flexible sensor array related to the embodiments of the application is shown. Figure Four ;

[0034] Figure 6 A structure diagram of the flexible sensor array related to the embodiments of the application is shown. Figure Five ;

[0035] Figure 7 Structure of flexible sensor array Figure Six .

[0036] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. The specific conditions not noted in the embodiments are implemented according to the conventional conditions or the conditions suggested by the manufacturers. The reagents or instruments not noted by the manufacturers are all conventional products that can be purchased in the market.

[0038] Hereinafter, the embodiments of the flexible sensor array and the preparation method thereof disclosed in the present application will be specifically described with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed descriptions are omitted. For example, there will be cases where detailed descriptions of matters well known in the art, repeated descriptions of substantially identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0039] The "ranges" disclosed in the present application are defined in the form of lower and upper limits, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The ranges defined in this way can include or exclude the end values, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if the ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges of 60-110 and 80-120 are also contemplated. In addition, if the minimum range values of 1 and 2 are listed, and if the maximum range values of 3, 4 and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "a-b" represents a shorthand notation for any integer combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is just a shorthand notation for these numerical combinations. In addition, when it is stated that a parameter is an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0040] If not particularly specified, all the embodiments and optional embodiments of the present application can be combined to form new technical solutions.

[0041] If not particularly specified, all the technical features and optional technical features of the present application can be combined to form new technical solutions.

[0042] If not particularly specified, all the steps of the present application can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method can further comprise step (c), which means that step (c) can be added to the method in any order. For example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0043] If not particularly specified, the "comprise" and "include" mentioned in the present application are open-ended, and can also be closed. For example, the "comprise" and "include" can mean that other components not listed can also be included, or only the listed components can be included.

[0044] If not particularly specified, in the present application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any one of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or A and B are both true (or exist).

[0045] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the technical solutions of the present application will be further described below in combination with the drawings and examples. However, the present application is not limited to the listed examples, and any known changes within the scope of the claimed rights of the present application should also be included.

[0046] The "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. The "in one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0047] In order to better understand the technical solutions of the present application, the following will be described in detail in combination with the drawings and specific embodiments of the specification.

[0048] In conventional technology, flexible sensor arrays are often manufactured on planar substrates such as wafers, flat molds, etc., which exhibit isotropic characteristics in terms of mechanics and electricity. However, when these sensors are transferred to a curved surface for deployment, the curvature and height of the curved surface differ in different directions, causing the originally isotropic sensors to experience irregular stretching or compression deformation when fitted to the anisotropic curved surface. Such deformation in turn causes the concentration of local stress, i.e. internal stress. In an ideal state, the shape of the curved surface and the sensor can perfectly complement each other, thereby achieving a stress-free state of the sensor. However, in reality, the sensor is usually assembled by multiple layers or components, and the manufacturing process requires the use of various equipment and technologies. This means that direct processing on the curved surface requires the processing equipment to have the ability to process in three-dimensional space, i.e. to change from the traditional two-axis planar processing mode to the three-axis or even more-axis three-dimensional (3D) processing mode. This change undoubtedly increases the complexity of the system, and also greatly increases the cost of equipment and technology. Therefore, direct processing of flexible sensor arrays on curved surfaces faces great challenges.

[0049] The present application provides a solution, specifically, a flexible sensor array preparation method, which utilizes the characteristics of shape memory polymers that can be restored after high-elastic deformation in the glass state, first replicates the target curved surface shape with shape memory polymers, and then further flattens the polymer after cooling to the glass state, thereby converting the curved surface preparation process of the flexible sensor array into a mature and controllable planar preparation process. Further combined with 3D printing technology, the preparation of highly personalized sensor array structures on shape memory polymers is realized. After building each functional layer of the sensor array, the shape polymer is triggered to recover by heating, so that the sensor array is deformed in the recovery of the shape memory polymer and is restored to a stress-free state that closely fits the curved surface, thereby effectively overcoming the internal stress interference of the flexible sensor array and improving the accuracy of the prepared sensor.

[0050] Reference Figure 1 The first aspect of the embodiment of the present application provides a flexible sensor array preparation method, comprising the following steps:

[0051] Step S10: coating a slurry of shape memory polymers on the surface of the target curved surface and solidifying to obtain a curved surface polymer;

[0052] In an available embodiment, a slurry of shape memory polymers prepared in advance is coated on the surface of the target curved surface, and the shape memory polymers are induced to solidify to obtain a curved surface polymer that fits the shape of the target curved surface.

[0053] Shape Memory Polymers (SMP) are a special class of high-performance materials that can change their initial shape under certain conditions and then restore their original shape when stimulated by external factors such as heat, electricity, light, or chemical stimuli. Shape memory polymers can restore their original shape when stimulated by specific stimuli.

[0054] For example, a slurry of shape memory polymer can be applied to the surface of a target curved surface by brushing, dipping, or other methods.

[0055] For example, the slurry of shape memory polymer includes a shape memory resin, which includes at least one of polyurethane, polyester, polystyrene-butadiene, EVA, and polyoctenamer.

[0056] Polyurethane-based shape memory materials, by introducing two or more types of fillers, can respond to multiple external stimuli such as heat, light, and chemicals, and exhibit shape memory effect. This material not only has excellent elasticity, but also has excellent biocompatibility and degradable properties, so it has been widely used in many fields.

[0057] Polyester, as a transparent and high-density polymer, has become an indispensable material in shape memory polymer applications due to its excellent strength and waterproof performance. Its easy-to-process characteristics make polyester easy to be made into various shapes and sizes of shape memory polymer products. Compared with other polymers, polyester (such as PET) is affordable and has significant cost-effectiveness, making it very suitable for mass production.

[0058] EVA material, due to its good flexibility and elasticity, can easily adapt to various complex curved surfaces and deformation environments, making it an ideal choice for preparing shape memory polymer products that require multiple deformation and recovery capabilities. In addition, EVA has excellent resistance to a variety of chemicals and weather conditions, providing additional environmental protection for shape memory polymer products.

[0059] Polyoctenamer is known for its high elasticity, excellent tensile and rebound performance, providing stable support and recovery for shape memory polymers. This material is particularly suitable for applications that require large deformation and rapid recovery. At the same time, the resistance of polyoctenamer to a variety of chemicals and high-temperature environments ensures the stability and reliability of shape memory polymer products in harsh conditions.

[0060] Exemplarily, the solidification mode of the shape memory polymer includes photo-solidification and / or thermal solidification. The photo-solidification refers to a process of achieving solidification by irradiation of a light source such as ultraviolet (UV) or visible light, so that the photosensitive component in the slurry undergoes chemical reaction. The thermal solidification refers to a process of achieving solidification by heating, so that the heat-sensitive component in the material undergoes chemical reaction.

[0061] It should be understood that the specific solidification mode of the shape memory polymer can be determined according to the specific components in the slurry thereof.

[0062] Exemplarily, the shape memory polymer needs to have a large deformation capacity, where the deformation capacity is greater than 100%. The shape memory polymer has shear thinning characteristics, which is beneficial to control the flow behavior thereof during processing and achieve coverage of the curved surface.

[0063] In step S20, the curved surface polymer is flattened and cooled to below the switching temperature of the shape memory polymer, to obtain a planar polymer, under the condition that the curved surface polymer is in the high-elastic state.

[0064] In an available embodiment, the curved surface polymer in the shape of the curved surface is peeled off from the target curved surface, and the temperature is raised to convert the curved surface polymer into the high-elastic state to flatten, and then the temperature is lowered to below the switching temperature of the shape memory polymer. As the temperature decreases, the chain segment motion in the shape memory polymer is gradually restricted, and below the switching temperature, the chain segment motion becomes very slow and almost freezes, forming a stable temporary shape, i.e., shape fixation, to obtain a planar polymer (i.e., planar polymer) in the shape of a plane.

[0065] Exemplarily, if the flexible sensor array needs to remove the substrate of the shape memory polymer for use, the switching temperature of the shape memory polymer can be determined according to the processing temperature. If the flexible sensor array does not need to remove the substrate of the shape memory polymer for use, the switching temperature of the shape memory polymer can be determined according to the use temperature, i.e., the shape memory polymer maintains the high-elastic state at the use environment temperature. This is because the flexible sensor array is mainly applied to sensing on the surface of a human or a robot, and in such applications, the flexible sensor array needs to deform along with the deformation of the curved surface, for example, the skin at the joint will elongate and shorten along with the joint movement, and the sensor attached to the skin also needs to change accordingly; therefore, the switching temperature thereof needs to be near the human body temperature or room temperature.

[0066] In an embodiment, the switching temperature is 30-50°C; for example, 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, etc. By using a shape memory polymer with a switching temperature of 30-50°C, energy can be saved effectively, and the process complexity of the heating and cooling operation can be reduced, for example, the cooling process can even be performed in an air-conditioned room. At the same time, the shape memory polymer with a switching temperature of 30-50°C can maintain a high elastic state at a daily use temperature.

[0067] In an embodiment, the step S20 of flattening the curved surface polymer comprises:

[0068] In step S21, the curved surface polymer is flattened by pulling and placed on a processing plane with a heat release tape attached, wherein the failure temperature of the heat release tape is lower than the switching temperature.

[0069] In an embodiment, the curved surface polymer is flattened by pulling along the plane, and the flattened curved surface polymer is placed on a processing plane with a heat release tape attached on the surface, wherein the failure temperature of the heat release tape is lower than the switching temperature, so that the heat release tape loses adhesion first and eliminates the fixation on the curved surface polymer during the process of restoring the shape of the heated curved surface polymer.

[0070] In a conventional manner, a metal flat plate is usually used to flatten the curved surface, that is, the curved surface is forced to flatten by pressure in the upward and downward directions. However, the flexible sensor array usually includes multiple layers of components (i.e., multiple functional layers), and thus the processed components are easily damaged. At the same time, the curved surface material will move to the periphery during the sliding process of the contact point during the pressing process until it cannot change, that is, it is flattened. However, the flexible sensor array uses a material with certain viscoelasticity and softness, and the friction is large during compression and the material itself is prone to bending. The whole curved surface may be squeezed into a ball instead of being unfolded as desired. After the compression is completed, the flat material pressed from the curved surface has no support for use. This is because the shape memory polymer is still relatively soft after the glass transition, and it is still prone to instability and unevenness under mechanical processing, making it difficult to achieve high-precision processing of the flexible sensor array. The embodiment of the present application can fix the curved surface polymer to apply force along the plane by using the heat release tape, thereby reducing the damage to the constructed components in multi-layer processing, and easily flattening the curved surface without being easily affected by the modulus or viscoelasticity of the material.

[0071] In an embodiment, the step S21 of flattening the curved surface polymer comprises:

[0072] In step S211, the edges of the curved surface polymer are fixed by an X-Y dual-axis motion frame, and are pulled apart along the X-axis and the Y-axis to tighten the curved surface polymer into a plane.

[0073] In an embodiment, the edges of the curved polymer are fixed by an X-Y dual-axis motion frame, and are pulled apart along the X-axis and Y-axis respectively to make the curved polymer flat, and then are pasted to the processing plane with the heat-releasing tape.

[0074] In the embodiment, compared with the conventional method of forcing the curved surface to be flat by clamping with a metal flat plate, the curved polymer is fixed by the heat-releasing tape in the embodiment, and force can be applied along the plane, so that the damage to the built component in the multi-layer processing is reduced, and the curved surface is easy to flatten and is not easily affected by the modulus or viscoelasticity of the material.

[0075] In step S30, each functional layer of the flexible sensor array is printed on the planar polymer layer by layer by using the 3D printing technology.

[0076] In an embodiment, the slurry for 3D printing is prepared, and then each functional layer of the flexible sensor array is printed on the planar polymer layer by layer by using the 3D printing technology.

[0077] In an embodiment, the flexible sensor array includes a plurality of sensing units, each functional layer of the sensing unit includes a first electrode layer, a sensing layer and a second electrode layer, the first electrode layers of each sensing unit are connected by a first wire, the second electrode layers of each sensing unit are connected by a second wire, and the functional layer of the flexible sensor array further includes a first support layer, a second support layer and a third support layer. In step S30, each functional layer of the flexible sensor array is printed on the planar polymer layer by layer by using the 3D printing technology, and the step includes:

[0078] In step S31, the first electrode layer and the first wire in the same horizontal plane are printed on the planar polymer by using the 3D printing technology.

[0079] In step S32, the first support layer is printed on the first support area pre-set on the planar polymer by using the 3D printing technology, wherein the first support area is in the same horizontal plane as the first electrode layer and the first wire, and vertically overlaps the corresponding area of the second wire.

[0080] In an embodiment, the flexible sensor array is composed of a plurality of circular sensing units, and the sensing units are connected by wires (for example, serpentine wires), and the functional layer of each sensing unit includes a vertically arranged first electrode layer, a sensing layer and a second electrode layer. The electrode layer in the flexible sensor array and the wire connected thereto can be made of the same material. The data collection method of the flexible sensor array can be the cross-positioning method, and therefore, the first electrode and the second electrode in the sensing unit can be vertically and crossly arranged (i.e., the first wire and the second wire are arranged in a row-column cross arrangement, and the first electrode and the second electrode in the same sensing unit are vertically arranged), so as to avoid the short circuit of the upper and lower electrodes due to the same distribution path.

[0081] In an embodiment, the first electrode layer 101 and the first conductive wire 102 can be printed simultaneously on the planar polymer by 3D printing technology using the same material. Figure 2 In order to avoid the deformation of the structure of the sensor before the material is solidified, the first support layer 103 is printed on the planar polymer in the first support area by 3D printing technology, wherein the first support area is at the same level as the first electrode layer 101 and the first conductive wire 102, and the first support area is vertically overlapped with the corresponding area of the second conductive wire, thereby supporting the second conductive wire to be printed later and avoiding the deformation of the structure of the sensor before the material is solidified.

[0082] The first electrode layer, the first conductive wire and the first support layer are at the same level and have the same height.

[0083] For example, the conductive wire between the sensing units can be in the form of a straight line, a serpentine, an arc, etc.

[0084] In step S33, the sensing layer is printed on the planar polymer by 3D printing technology.

[0085] In step S34, the second support layer is printed on the planar polymer in the second support area by 3D printing technology, wherein the second support area is at the same level as the sensing layer, and the second support area is vertically overlapped with the corresponding area of the first conductive wire and the second conductive wire.

[0086] In an embodiment, the sensing layer 104 of each sensing unit is printed on the planar polymer by 3D printing technology. Figure 3 In order to avoid the deformation of the structure of the sensor before the material is solidified, the second support layer 105 is printed on the planar polymer in the second support area by 3D printing technology, wherein the second support area is at the same level as the sensing layer 104, and the second support area is vertically overlapped with the corresponding area of the first conductive wire and the second conductive wire.

[0087] In step S35, the second electrode layer and the second conductive wire are printed on the planar polymer by 3D printing technology.

[0088] In step S36, the third support layer is printed on the planar polymer in the third support area by 3D printing technology, wherein the third support area is at the same level as the second electrode layer and the second conductive wire, and the third support area is vertically overlapped with the corresponding area of the first conductive wire.

[0089] In an embodiment, the sensing layer 104 of each sensing unit is printed on the planar polymer by 3D printing technology. Figure 4The second electrode layer 106 and the second conductive wire 107 can be printed simultaneously on the planar polymer by 3D printing technology. In order to avoid deformation of the sensor structure caused by incomplete curing of the material, a third support layer 108 is printed on the planar polymer by 3D printing technology in a third support area preset on the planar polymer. The third support area is in the same horizontal plane as the second electrode layer 106 and the second conductive wire 107, and vertically overlaps the corresponding area of the first conductive wire.

[0090] In the embodiment, different functional layers of the flexible sensor array are continuously printed by 3D printing technology, so as to reduce stress interference caused by assembly process, and to realize preparation of a highly personalized sensor array structure on the shape memory polymer.

[0091] In step S40, the planar polymer is restored to the curved polymer and the functional layers of the flexible sensor array are completely cured when the temperature is increased to above the switching temperature, so as to obtain the flexible sensor array.

[0092] In an embodiment, the functional layers of the flexible sensor array are induced to be preliminarily cured, and then the temperature is increased to above the switching temperature of the shape memory polymer. At this time, the adhesive property of the heat release tape is invalid, and the planar polymer is restored from the planar shape to the curved shape, i.e., the curved polymer. Then, the functional layers of the flexible sensor array are completely cured, so that the functional layers also present the curved state, and the flexible sensor array is obtained.

[0093] For example, referring to FIG. 2A, Figure 5 The functional layers 100 of the flexible sensor array are prepared on the planar polymer 201 by 3D printing. Then, the functional layers 100 of the flexible sensor array are induced to be preliminarily cured, and the temperature is increased to above the switching temperature of the shape memory polymer. At this time, referring to FIG. 2B, Figure 6 The planar polymer 201 is restored to the curved polymer 202, and the functional layers 100 of the flexible sensor array also present the curved state, so that the flexible sensor array is obtained. According to the use requirement, the curved polymer 202 can be further removed. For example, referring to FIG. 2C, Figure 7 .

[0094] In the present embodiment, the characteristics of shape memory polymer in high elastic state after deformation in glass state are utilized, the target curved surface shape is first copied by shape memory polymer, and then the polymer is flattened after further cooling to glass state, so that the curved surface preparation process of the flexible sensor array is converted into a mature controllable planar preparation process. Further combined with 3D printing technology, different functional layers of the flexible sensor array are continuously printed, the stress interference caused by the assembly process is reduced, and the preparation of a highly personalized sensor array structure on the shape memory polymer is realized. After the construction of each functional layer of the sensor array, the shape polymer is triggered to recover by heating, so that the sensor array is deformed in the recovery of the shape memory polymer and is recovered to a stress-free state close to the curved surface, thereby effectively overcoming the internal stress interference of the flexible sensor array and improving the accuracy of the prepared sensor.

[0095] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the patent protection scope of the present application.

Claims

1. A method of fabricating a flexible sensor array, comprising: The method comprises the following steps: coating a slurry of shape memory polymer on the surface of a target curved surface and solidifying to obtain a curved surface polymer; flattening the curved surface polymer when it is in a high-elastic state and cooling to below a switching temperature of the shape memory polymer to obtain a planar polymer; printing each functional layer of the flexible sensor array on the planar polymer layer by layer by 3D printing technology; heating to above the switching temperature to make the planar polymer return to a curved surface polymer and completely solidify each functional layer of the flexible sensor array when each functional layer of the flexible sensor array is preliminarily solidified, to obtain the flexible sensor array.

2. The method of claim 1, wherein the flexible sensor array is prepared by the steps of: The step of flattening the curved surface polymer comprises: ​ flattening the curved surface polymer by pulling and placing it on a processing plane with a thermal release tape, wherein the failure temperature of the thermal release tape is lower than the switching temperature.

3. The method for fabricating a flexible sensor array as described in claim 2, characterized in that, The step of flattening the curved surface polymer by pulling comprises: fixing the edges of the curved surface polymer by an X-Y double-axis motion frame and pulling apart along the X-axis and Y-axis to make it tense into a plane.

4. The method for fabricating a flexible sensor array as described in claim 1, characterized in that, The flexible sensor array comprises a plurality of sensing units, each functional layer of the sensing units comprises a first electrode layer, a sensing layer and a second electrode layer, the first electrode layers of each sensing unit are connected by a first wire, the second electrode layers of each sensing unit are connected by a second wire, and the step of printing each functional layer of the flexible sensor array on the planar polymer layer by layer by 3D printing technology comprises: printing the first electrode layer and the first wire on the same horizontal plane of the planar polymer by 3D printing technology; printing the sensing layer on the planar polymer by 3D printing technology; printing the second electrode layer and the second wire on the same horizontal plane of the planar polymer by 3D printing technology.

5. The method for fabricating a flexible sensor array as described in claim 4, characterized in that, The functional layer of the flexible sensor array further comprises a first support layer, a second support layer and a third support layer, and the step of printing each functional layer of the flexible sensor array on the planar polymer layer by layer by 3D printing technology comprises: printing the first support layer on a preset first support area of the planar polymer by 3D printing technology, wherein the first support area is in the same horizontal plane as the first electrode layer and the first wire and vertically overlaps with a corresponding area of the second wire; printing the second support layer on a preset second support area of the planar polymer by 3D printing technology, wherein the second support area is in the same horizontal plane as the sensing layer and vertically overlaps with corresponding areas of the first wire and the second wire; printing the third support layer on a preset third support area of the planar polymer by 3D printing technology, wherein the third support area is in the same horizontal plane as the second electrode layer and the second wire and vertically overlaps with a corresponding area of the first wire.

6. The method for fabricating a flexible sensor array as described in claim 1, characterized in that, The switching temperature is 30-50℃.

7. A flexible sensor array, characterized by The flexible sensor array is obtained by the method according to any one of claims 1-6.

8. The flexible sensor array of claim 7, wherein, The flexible sensor array comprises a plurality of sensing units connected by wires, and a functional layer of each sensing unit comprises a first electrode layer, a sensing layer and a second electrode layer arranged vertically.

9. The flexible sensor array of claim 8, wherein, The first electrode layers of each sensing unit are connected by first wires, and the second electrode layers of each sensing unit are connected by second wires, and the first wires and the second wires are arranged in a row-column cross arrangement.

10. The flexible sensor array of claim 9, wherein, The first electrode layer and the first wire are made of the same material, and the second electrode layer and the second wire are made of the same material.

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