Highly-bent pixel-free flexible tactile sensor and preparation method thereof

Abstract

The invention provides a high-bending pixel-free flexible tactile sensor and a preparation method thereof, the pixel-free flexible tactile sensor comprises two tactile sensing layers which are oppositely attached, and each tactile sensing layer comprises a soft polymer substrate thin film, a flexible polymer substrate thin film and a flexible polymer substrate thin film, a flexible viscous film disposed on the soft polymer substrate film; the insulating layer is arranged on the edge of the flexible adhesive film; the pixel-free conductive thin film is arranged in the middle of the flexible viscous thin film; the electrode layer is arranged at one end of the pixel-free conductive film; and an electrode led out from the electrode layer. The sensor has a good non-pixelated characteristic, the number of pixel points is reduced, wiring complexity and signal interference are reduced, durability in actual use is improved, and the sensor is simple in structure, convenient to operate and low in cost.

Description

Technical Field

[0001] The present invention relates to the field of sensors, and particularly to a highly bendable pixel - less flexible tactile sensor and a preparation method thereof. Background Art

[0002] The human - machine interaction system plays an indispensable role in promoting the symbiotic relationship between humans and machines, especially in frontier technology fields such as virtual reality, augmented reality, and bionic robot systems. Recently, the trend of integrating flexible, skin - like tactile electronic devices into the human - machine interface system has attracted wide attention in the industry. These advanced tactile sensors can convert human behaviors into machine - interpretable electronic signals, thus achieving more precise and efficient human - machine interaction. Different from traditional rigid devices, these soft skin - like electronic products can closely conform to the changes of the human body skin and keep in sync with the body's dynamic movements. This high degree of adaptability not only enhances the naturalness and comfort of the human - machine interface but also significantly improves the user experience. By integrating these advanced tactile sensor technologies, the human - machine interface system can achieve a higher level of interaction, which is not only more perfect in function but also more intuitive and closer to the natural interaction mode between humans and the environment.

[0003] However, current tactile sensors face many problems in the bent state. On the one hand, functional devices are extremely prone to deformation, which in turn interferes with the transmitted signals, resulting in the failure of the tactile positioning function. On the other hand, their structures are too complex and there are too many pixel points, making operation extremely inconvenient and further exacerbating the operation difficulty. Moreover, existing tactile sensors usually require complex wiring and a large number of sensing pixel points, which not only increases the manufacturing cost but also reduces the durability and reliability of the sensors. In addition, in application scenarios that require long - term bending or frequent bending, such as wearable devices and soft robots, the performance and reliability of existing tactile sensors are difficult to meet the actual needs. Summary of the Invention

[0004] Aiming at the problems of existing tactile sensors in the bent state, such as easy deformation of functional devices, serious signal interference, and complex structures, the present invention proposes a highly bendable pixel - less flexible tactile sensor and a preparation method thereof. By optimizing the material selection and preparation process, a highly bendable flexible tactile sensor with high mechanical stability, simplified structure, and convenient operation is realized.

[0005] The present invention provides a highly bendable pixel - less flexible tactile sensor, which includes two relatively adhered tactile sensing layers. Among them, each tactile sensing layer includes: A soft polymer substrate film; A flexible adhesive film disposed on the soft polymer substrate film; Insulating layers disposed on two edges of the flexible adhesive film; A pixel-less conductive film disposed at the middle position of a flexible adhesive film; An electrode layer disposed at one end of the pixel-less conductive film; An electrode led out from the electrode layer.

[0006] Preferably, the tactile sensing layer further includes: A protective layer disposed on the electrode layer.

[0007] Preferably, the thickness of the pixel-less conductive film is lower than that of the insulating layer.

[0008] Preferably, the two tactile sensing layers are closely attached face to face by means of an adhesive or physical pressing.

[0009] Preferably, the thickness of the soft adhesive film is 1-5 microns.

[0010] Preferably, the thickness of the insulating layer is 5-10 microns, and the thickness of the pixel-less conductive film is 1-3 microns.

[0011] Preferably, the size of the electrode layer is 5mm × 5mm, and the thickness is 1-2 microns; the material of the protective layer is a polyester insulating tape, and the thickness is 10-20 microns.

[0012] The embodiment of the present invention also provides a preparation method of a highly bendable pixel-less flexible tactile sensor as described above, which is characterized by including the following steps: S1: Evenly spread a soft polymer material in a vessel according to a designed shape, and perform a drying and curing treatment at a set temperature, and then take out the cured soft polymer substrate film; S2: Form a soft adhesive film on the surface of the soft polymer substrate film by using a vacuum deposition technique; S3: Use a flexible 3D printing technique to print insulating layers at both edge positions of the soft adhesive film; S4: Use a flexible 3D printing device to print a pixel-less conductive film in the middle area of the soft adhesive film, and control its thickness to be lower than that of the insulating layer to achieve uniform transmission of electrical signals; S5: Use a flexible 3D printing technique to print an electrode layer at one end of the pixel-less conductive film to form an electrode lead-out structure, and obtain a tactile sensing layer; S6: Prepare a highly bendable pixel-less flexible tactile sensor according to the tactile sensing layer.

[0013] Preferably, in step S1, the soft polymer material is a cyclic siloxane monomer and a catalyst mixed in a ratio of 1:10, the oven curing temperature is 60-80 °C, and the curing time is 2-3 hours.

[0014] Preferably, step S5 further includes: Printing a protective layer on the upper end of the electrode layer.

[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. The highly bendable pixel-less flexible tactile sensor prepared by the present invention uses a soft polymer matrix as a substrate, on which a soft viscous film is deposited. With excellent flexibility and adhesion, after the conductive film is printed on the soft viscous film, even if the tactile sensor undergoes bending deformation, the conductive film can still firmly adhere to the soft viscous film adhered to the soft polymer substrate, effectively reducing the detachment phenomenon of the device and ensuring the tactile positioning function of the sensor in the bent state. At the same time, the sensor has good pixel-less characteristics, reducing the number of pixel points, lowering the wiring complexity and signal interference, improving the durability in actual use, and having a simple structure, convenient operation and low cost.

[0016] 2. The highly bendable pixel-less flexible tactile sensor fabricated by the present invention can be designed into various shapes and structures according to different molds for its soft polymer substrate film, so as to be able to fit diverse actual application scenarios and achieve the goal of multi-scenario interactive applications. Description of the Drawings

[0017] Figure 1 is a schematic diagram of the highly bendable pixel-less flexible tactile sensor of Example 1; Figure 2 is a schematic diagram of the soft polymer substrate film of Example 1; Figure 3 is a schematic diagram of depositing a soft viscous film on the soft polymer substrate film of Example 1; Figure 4 is Figure 3 a partial enlarged view of; Figure 5 is a schematic diagram of printing an insulating layer on the soft viscous film of Example 1; Figure 6 is Figure 5 a partial enlarged view of; Figure 7 is a schematic diagram of printing a pixel-less conductive film layer on the soft viscous film of Example 1; Figure 8 is Figure 7 a partial enlarged view of; Figure 9 is a schematic diagram of printing an electrode layer on the pixel-less conductive film layer of Example 1; Figure 10 is Figure 9 a partial enlarged view of; Figure 11 is a schematic diagram of pasting a protective layer on the electrode layer of Example 1; Figure 12 is Figure 11 a partial enlarged view of; Figure 13 is a schematic diagram of the tactile sensing layer of the flexible tactile sensor of Example 1; Figure 14 is Figure 13 a partial enlarged view of; Figure 15 Schematic diagram of the highly bendable pixel - less flexible tactile sensor of Example 2.

[0018] The reference numerals are as follows: 1, soft polymer substrate film; 2, flexible adhesive film; 3, insulating layer; 4, pixel - less conductive film; 5, electrode layer; 6, protective layer. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] In the present invention, for the description, the orientation or positional relationship indicated by "upper", "lower", "left", "right", "front" and "rear" is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention, rather than indicating or implying that the device referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present invention. For those of ordinary skill in the art, the specific meanings of the above - mentioned terms in this application can be understood according to specific circumstances.

[0021] In addition, in the description of this application, unless otherwise specified, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0022] The present invention provides a highly bendable pixel - less flexible tactile sensor and its preparation method. By optimizing the material selection and preparation process, a highly bendable flexible tactile sensor with high mechanical stability, simplified structure and convenient operation is realized. Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0023] Referring to Figure 1 , the first embodiment of the present invention provides a highly bendable pixel - less flexible tactile sensor, including two relatively adhered tactile sensing layers. Among them, each tactile sensing layer includes: Soft polymer substrate film 1.

[0024] In this embodiment, the material for fabricating the soft polymer substrate film 1 can be the soft polymer elastomer PDMS. Of course, the soft polymer substrate film 1 can also be fabricated using other soft polymer elastomers or Ecoflex or hydrogels and other materials, and these solutions are all within the protection scope of the present invention and will not be elaborated here.

[0025] In this embodiment, the shape of the soft polymer substrate film 1 can be square (as Figure 2 shown), or it can be other shapes, and the present invention does not make specific limitations.

[0026] The flexible adhesive film 2 on the soft polymer substrate film 1.

[0027] In this embodiment, as Figure 3 and Figure 4 shown, the soft adhesive film 2 can be made of polyimide film. As a simple replacement for this embodiment, the soft adhesive film 2 can also be fabricated using materials such as polytetrafluoroethylene, polyvinyl alcohol, or polyester, and the present invention does not make specific limitations.

[0028] Among them, with its excellent flexibility and adhesiveness, the soft adhesive film 2 ensures that the pixel-free conductive film 4 can still firmly adhere to the soft adhesive film 2 adhered to the soft polymer substrate film 1 when the tactile sensor undergoes bending deformation and is not prone to detachment. The flexibility of this soft adhesive film 2 enables it to adapt to the bending and deformation of the tactile sensor, while its adhesiveness ensures a tight connection between the pixel-free conductive film 4 and the soft polymer substrate film 1. This characteristic is crucial for the performance of the tactile sensor because it ensures that the pixel-free conductive film 4 can remain stable under various usage conditions, thereby guaranteeing the reliability and durability of the sensor.

[0029] In this embodiment, particularly, the thickness of the soft adhesive film 2 is 1 - 5 microns.

[0030] The insulating layer 3 printed on both edges of the flexible adhesive film 2.

[0031] Specifically, as Figure 5 and Figure 6 shown, in this embodiment, the insulating layer 3 can be made of silicone rubber. As a simple replacement for this embodiment, the insulating layer 3 can also be electronic potting compound, silicone potting compound, natural rubber, styrene-butadiene rubber, or acrylate adhesive, etc., and the present invention does not make specific limitations.

[0032] Among them, the insulating layer 3 can be printed on the edge of the flexible adhesive film 2 through advanced flexible 3D printing technology.

[0033] The pixel-free conductive film 4 at the middle position of the flexible adhesive film 2.

[0034] In this embodiment, as Figure 7 and Figure 8 shown, the pixel-less conductive film 4 makes full use of the high precision and flexibility of the flexible 3D printing technology, and can accurately deposit the conductive material at the predetermined position according to the design requirements, forming a uniform and continuous pixel-less conductive film 4, while the precise thickness requirement can be achieved. This pixel-less conductive film 4 plays a key conductive role in the flexible tactile sensor, and can effectively transmit electrical signals to achieve accurate perception and feedback of tactile information.

[0035] Furthermore, in this embodiment, the pixel-less sensing characteristic means that there are no independent pixels on the designed tactile sensor, so any position can be well recognized, and a specific signal response is generated accordingly. Compared with the pixelated tactile sensor, the designed pixel-less tactile sensor is completely flexible and not affected by the wiring topology.

[0036] In this embodiment, particularly, the thickness of the insulating layer 3 is 5-10 microns, and the thickness of the pixel-less conductive film 4 is 1-3 microns.

[0037] The electrode layer 5 on one end of the pixel-less conductive film 4.

[0038] The electrode is led out from the electrode layer 5; the protective layer 6 on the electrode layer 5.

[0039] As Figures 9 to 10 shown, in this embodiment, the electrode layer 5 is in good contact with the pixel-less conductive film 4, which provides convenience for subsequent circuit connection, making the signal transmission of the entire pixel-less tactile sensor more stable and reliable. And through precise printing technology, the thickness and shape of the electrode layer 5 can be effectively controlled, thereby optimizing the performance of the sensor.

[0040] In this embodiment, as Figures 11 to 12 shown, the protective layer 6 can provide protection for the electrode layer 5.

[0041] In this embodiment, particularly, the size of the electrode layer 5 is 5mm × 5mm, and the thickness is 1-2 microns; the material of the protective layer 6 is polyester insulating tape, and the thickness is 10-20 microns.

[0042] In this embodiment, as Figure 13 shown, by precisely assembling the two tactile sensing layers in a face-to-face manner according to the hierarchical assembly process, a highly bendable pixel-less tactile sensor can be obtained.

[0043] When using this highly bendable pixel-less flexible tactile sensor, the designed pixel-less structure can actually represent a series of resistance units, equivalent to the integration of multiple sensing pixels. The spacing area between the contact regions is similar to the air switch between the upper and lower resistance units. When an external mechanical stimulus is applied to the touch position of the pixel-less flexible tactile sensor, the corresponding air switch closes, thus realizing the function of tactile positioning. Therefore, the designed pixel-less structure endows the pixel-less flexible tactile sensor with sensing and recognition capabilities without the need for large-scale integration of sensing pixels. This greatly simplifies the structure of the device, making the operation efficient and convenient, and thus reducing the difficulty of the manufacturing process.

[0044] Embodiment 2 As Figure 15 shown, the difference between this embodiment and Embodiment 1 is that: in this embodiment, the soft polymer substrate film 1 is designed to be octagonal, the octagonal flexible adhesive film 2 is deposited on the octagonal soft polymer substrate film 1, the octagonal insulating layer 3 is printed around the octagonal flexible adhesive film 2, and then the octagonal pixel-less conductive film layer 4 is printed on the inner side of the octagonal insulating layer 3. The electrode layer 5 is printed on a section on the right side of the octagonal pixel-less conductive film 4, and finally the protective layer 6 is pasted on the electrode layer 5. The rest is the same as that in Embodiment 1 and will not be elaborated here. The flexible tactile sensor of this embodiment can be applied to application scenarios where the sensor needs to be placed on the back of the hand.

[0045] Please refer to Figures 1 to 14 together. The third embodiment of the present invention also provides the manufacturing method of the above-mentioned highly bendable pixel-less flexible tactile sensor, including the following steps: Step 1: Place the soft polymer material flat in a long rectangular container, and then put it into an oven for drying and curing treatment at a set temperature to make it fully dry and cured into a shape. After curing is completed, take out the soft polymer from the long rectangular container and make it into a shape with a specific length-width ratio through precision machining to serve as the soft polymer substrate film 1, laying the substrate foundation for subsequent manufacturing processes.

[0046] Specifically, mix the cyclic siloxane monomer with the catalyst in a ratio of 1:10, stir well; then, perform degassing treatment on the polymerized PDMS liquid to remove air bubbles; next, pour the degassed PDMS liquid into a mold to fully fill the mold; then, put the mold into an oven and cure it at 60 - 80 °C for 2 - 3 hours to completely cure the PDMS liquid into a soft polymer elastomer.

[0047] Further, as Figure 2As shown, the cured soft polymer elastomer PDMS is taken out of the mold, demolded, and cut as needed to meet specific application requirements, and then cut into a rectangular structure of 8 cm × 2 cm to be used as the soft polymer substrate film 1 of the present invention.

[0048] Step 2: Install the soft sticky film 2 on the soft polymer substrate film 1 described in Step 1 by means of vacuum deposition, so that the pixel-less conductive film 4 in the flexible tactile sensor is not easily detached after bending.

[0049] Specifically, as Figures 3 - 4 shown, the soft sticky film 2 can be installed on the soft polymer substrate film 1 by vacuum deposition. The specific process is to first place the soft polymer substrate film 1 in a vacuum chamber and evacuate it to a high vacuum environment of 10 -5 to 10 -6 Pascal. Subsequently, the soft polymer substrate film 1 is cleaned and surface-treated. Then, physical vapor deposition technology is used to evaporate or sputter the coating material. The material passes through in a vacuum and is uniformly deposited on the soft polymer substrate film 1. By controlling parameters, the film thickness and uniformity are precisely adjusted. Finally, the chamber is cooled and evacuated to atmospheric pressure to take out the soft polymer coated substrate.

[0050] In this embodiment, the material of the soft sticky film 2 is a polyimide film. As a simple replacement for this embodiment, the material of the soft sticky film 2 can also be made of polytetrafluoroethylene, polyvinyl alcohol, or polyester.

[0051] Step 3: Use advanced flexible 3D printing technology to fabricate the insulating layer 3. By precisely controlling the printing nozzle, the insulating material is printed evenly and stably at both edge positions of the soft sticky film 2.

[0052] Specifically, as Figures 5 - 6 shown, in this embodiment, the process of fabricating the insulating layer 3 using advanced flexible 3D printing technology first involves precisely controlling the 3D printer, especially the fine adjustment of the printing nozzle. Before starting the printing, the insulating material needs to be precisely loaded into the nozzle of the 3D printer. These insulating materials usually have good insulating properties and appropriate fluidity. Through precise planning of the printing path by 3D printing software, it is ensured that the insulating material can be evenly and stably deposited at both edge positions of the soft sticky film. During the printing process, the nozzle will print the insulating material in a precise thickness and shape according to the preset path and parameters to form the insulating layer 3. This precise printing technology can ensure the uniformity and stability of the insulating layer, thereby improving the performance and reliability of the entire flexible tactile sensor.

[0053] In this embodiment, the insulating layer 3 is made of silicone rubber. As a simple replacement for this embodiment, the insulating layer 3 can also be made of electronic potting glue, silicone potting glue, natural rubber, styrene-butadiene rubber, or acrylate adhesive, etc.

[0054] Step 4: Use a flexible 3D printing device to precisely print a pixel-free conductive film 4 in the middle area of the soft sticky film 2, and control the thickness of the pixel-free conductive film 4 to be lower than the thickness of the insulating layer.

[0055] Specifically, as Figures 7 - 8 shown, in order to fabricate the pixel-free conductive film 4, during the process of precisely printing the pixel-free conductive film 4 in the middle area of the soft sticky film 2 using a flexible 3D printing device, it is first necessary to precisely set and debug the parameters of the 3D printer. Specifically, the temperature of the print head usually needs to be controlled between 80°C and 100°C to ensure that the conductive material can be deposited evenly and continuously on the surface of the soft sticky film 2. At the same time, the moving speed of the print head should be maintained at 5 to 10 mm / s to ensure the printing accuracy and stability. In addition, the distance between the print head and the soft sticky film 2 should be controlled at 0.1 to 0.2 mm to ensure that the material can be accurately deposited at the predetermined position. During the printing process, a pixel-free conductive film layer 4 with a size of 8 cm × 2 mm is printed, and precise control over the thickness of the pixel-free conductive film is achieved, making it lower than the thickness of the insulating layer. This not only helps improve the conductivity of the pixel-free conductive film but also ensures that it is not prone to short circuit or open circuit phenomena during subsequent use.

[0056] In this embodiment, the material used for the pixel-free conductive film 4 is graphene. As a simple alternative to this embodiment, the pixel-free conductive film 4 can also be made of other pixel-free conductive films such as carbon nanotubes, gold conductive films, or indium tin oxide.

[0057] Step 5: Use flexible 3D printing technology to print an electrode layer 5 at one end of the pixel-free conductive film 4, thereby realizing the extraction of the electrode wire.

[0058] Specifically, as Figures 9 - 10 shown, in order to achieve the function of conductive connection, use a printer to evenly deposit a conductive material to form an electrode layer 5 with a size of 5 mm × 5 mm. After printing, cure the electrode layer, then connect the electrode layer 5 to an external circuit with a wire, and finally detect the conductivity and contact situation of the electrode layer 5 to ensure that it meets the application requirements.

[0059] In this embodiment, the material of the electrode layer 5 can be silver paint. As a simple replacement for this embodiment, other conductive layer materials with conductive functions such as copper paste, gold paste, aluminum paste, or carbon nanotube paste can also be used.

[0060] Step 6: Paste the protective layer 6 on the upper end of the electrode layer 5, which effectively prevents accidental contact between the two upper and lower electrode layers 5, avoids abnormal sensor performance or damage caused by short circuit, and thus completes the construction of the lower tactile sensing layer of the pixel-less tactile sensor.

[0061] Specifically, as Figures 11 - 12 shown, paste a 5 mm × 5 mm protective layer 6 of the same size as the electrode layer 5 on the upper end of the electrode layer 5 to ensure the orderly transmission of electrical signals between the electrode layers, providing a strong guarantee for the stable operation and accurate perception of the entire sensor.

[0062] In this embodiment, the material of the protective layer 6 can be polyester insulating tape. As a simple replacement for this embodiment, other protective layer materials with protection functions such as polyvinyl chloride tape, polyimide tape, acrylic tape or cloth-based tape can also be used.

[0063] Step 7: Prepare two tactile sensing layers successively according to the foregoing steps.

[0064] Among them, after the preparation of the two tactile sensing layers is completed, they are closely adhered face to face by means of an adhesive or physical pressing, that is, a highly bendable pixel-less flexible tactile sensor is obtained.

[0065] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A highly curved pixel-free flexible tactile sensor, characterized in that: The invention comprises two relatively fitted tactile sensing layers, wherein each tactile sensing layer comprises: Soft polymer substrate films; A flexible adhesive film disposed on a soft polymer substrate film; an insulating layer disposed on the edge of the flexible adhesive film; A pixel-free conductive film disposed in the middle of the flexible adhesive film; An electrode layer is arranged at one end of the non-pixel conductive film; Electrodes extending from the electrode layer.

2. The highly curved pixel-free flexible tactile sensor according to claim 1, characterized in that: The touch sensing layer also includes: A protective layer is provided on the electrode layer.

3. The highly curved pixel-free flexible tactile sensor according to claim 1, characterized in that: The thickness of the non-pixel conductive film is less than the thickness of the insulating layer.

4. The highly curved pixel-free flexible tactile sensor according to claim 1, characterized in that: The two tactile sensing layers are tightly fitted face to face by means of adhesive or physical pressing.

5. The highly curved pixel-free flexible tactile sensor according to claim 1, wherein: The thickness of the soft adhesive film is 1-5 microns.

6. The highly curved pixel-free flexible tactile sensor according to claim 3, characterized in that: The thickness of the insulating layer is 5-10 microns, and the thickness of the non-pixel conductive film is 1-3 microns.

7. The highly curved pixel-free flexible tactile sensor according to claim 2, wherein: The electrode layer has a size of 5mm×5mm and a thickness of 1-2 micrometers; the protective layer is made of polyester insulating tape and has a thickness of 10-20 micrometers.

8. The method for preparing a highly curved pixel-free flexible tactile sensor according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: evenly spread the soft polymer material in a container according to the designed shape, dry and solidify it at a set temperature, and then take out the solidified soft polymer substrate film; S2: forming a soft and sticky film on the surface of a soft polymer substrate film using vacuum deposition technology; S3: Use flexible 3D printing technology to print an insulating layer at the edges of both ends of the soft sticky film; S4: Printing a pixel-free conductive film in the middle area of ​​the soft viscous film using a flexible 3D printing device, and controlling its thickness to be lower than that of the insulating layer to achieve uniform transmission of electrical signals; S5: Printing an electrode layer at one end of the non-pixel conductive film using a flexible 3D printing technology to form an electrode lead-out structure to obtain a tactile sensing layer; S6: A highly curved pixel-free flexible tactile sensor is prepared based on the tactile sensing layer.

9. The preparation method according to claim 8, characterized in that: In step S1, the soft polymer material is a mixture of cyclic siloxane monomer and catalyst in a ratio of 1:10, the oven curing temperature is 60-80° C., and the curing time is 2-3 hours.

10. The preparation method according to claim 8, characterized in that: Step S5 also includes: A protective layer is printed on the upper end of the electrode layer.

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