A robot flexible touch skin based on transparent conductive copper mesh and a preparation method thereof

Abstract

The present application relates to the technical field of transparent conductive material and touch sensing, in particular to a robot flexible touch skin based on transparent conductive copper grid and a preparation method thereof, which comprises, from bottom to top, a transparent substrate, a metal grid copper transparent electrode layer, a copper grid protection layer, a control circuit layer, an insulation adaptation layer, a multi-modal sensing layer and an encapsulation layer. The flexible touch skin of the present application adopts a multi-layer composite structure design, has excellent flexibility and light transmission, can closely fit the curved surface of the robot and does not block the vision sensor, adapts to the shape and use demand of various robots, effectively improves the environmental tolerance of the electrode through the protection layer design, enhances the anti-interference ability of the signal through the double-layer electromagnetic shielding structure, enriches the sensing dimension through the multi-modal sensing layer, realizes the synchronous detection of touch and multi-physical quantity, has high overall preparation process compatibility, is beneficial to large-scale production, and reduces the preparation and later maintenance cost of the robot touch skin.

Description

Technical Field

[0001] This invention relates to the technical field of transparent conductive materials and touch sensing, specifically to a flexible robotic touch skin based on a transparent conductive copper mesh and its preparation method. Background Technology

[0002] As robotics technology advances towards intelligence and biomimicry, flexible touch-sensitive skin has become a core component for improving human-robot interaction and operational safety. However, traditional robot touch-sensitive skin suffers from numerous technical shortcomings. Its touch electrodes are mostly made of rigid materials, making it impossible to conform to the complex curves of a robot's limbs. Furthermore, its lack of transparency easily obstructs built-in visual sensors, affecting collaborative operation. Simultaneously, existing products have high manufacturing and maintenance costs, the electrodes are susceptible to environmental corrosion and failure, and they can only achieve single-sensory touch perception, failing to meet the complex interaction and environmental adaptation needs of robots in different scenarios. Therefore, there is an urgent need for a touch-sensitive skin solution that combines flexible fit, high light transmittance, multi-sensory dimensions, and environmental tolerance. Summary of the Invention

[0003] The purpose of this invention is to provide a robotic flexible touch skin based on a transparent conductive copper mesh and its preparation method, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a robot flexible touch skin based on a transparent conductive copper mesh, comprising, from bottom to top: a transparent substrate, a metal mesh copper transparent electrode layer, a copper mesh protective layer, a control circuit layer, an insulating adapter layer, a multimodal sensing layer, and an encapsulation layer; The transparent substrate is a flexible transparent polymer film, which is used to provide mechanical support for the overall structure and ensure optical transmittance. The metal mesh copper transparent electrode layer is formed on a transparent substrate, and the capacitive touch matrix is ​​composed of orthogonally arranged copper wires to realize touch signal sensing and transmission. The copper mesh protective layer is coated on the surface of the metal mesh copper transparent electrode layer. It is a transparent anti-oxidation film used to protect the copper mesh electrode from environmental corrosion. The control circuit layer is electrically connected to the metal mesh copper transparent electrode layer and the multimodal sensing layer, and is used for signal acquisition, processing and anti-interference. The insulating adapter layer is disposed between the control circuit layer and the multimodal sensing layer. It is a flexible insulating dielectric layer used to isolate the interlayer structure and ensure the stability of the capacitor signal. The multimodal sensing layer integrates flexible sensing units to realize the sensing of multiple physical quantities in addition to touch control; The encapsulation layer is a flexible, transparent, and wear-resistant film used to protect the internal functional layers and improve surface durability.

[0005] Preferably, the transparent substrate is made of polyimide or polyethylene terephthalate material with a thickness of 50-100 μm and the surface is plasma modified.

[0006] Preferably, the copper wires of the metal mesh copper transparent electrode layer have a wire width of 5-20 μm, a spacing of 100-300 μm, a thickness of 20-50 nm, and a copper wire purity of not less than 99.9%.

[0007] Preferably, the copper mesh protective layer is a SiO2-TiO2 composite film with a thickness of 5-10 nm, which is prepared by atomic layer deposition and completely covers the surface of the copper wire.

[0008] Preferably, the control circuit layer includes a microcontroller, a signal processing module, a filtering module, and a multimodal signal fusion module. The filtering module adopts a double-layer electromagnetic shielding structure composed of copper foil and polyimide.

[0009] Preferably, the insulating adapter layer is made of polydimethylsiloxane or polyurethane material, with a thickness of 30-50 μm and a surface with a micro-bump structure, the micro-bumps having a diameter of 5-10 μm and a spacing of 20 μm.

[0010] Preferably, the multimodal sensing layer includes a distributed flexible pressure sensing array and a temperature and humidity sensing unit, with the pressure sensing array unit spacing being 50-100μm.

[0011] Preferably, the encapsulation layer is made of transparent polyolefin elastomer or fluororubber material, with a thickness of 40-60μm, and the surface is treated with anti-scratch and anti-fingerprint properties, and the pencil hardness is not less than 3H.

[0012] A method for preparing a robotic flexible touch-sensitive skin includes the following steps: S1: Prepare a transparent substrate and perform plasma surface modification; S2: A metal mesh copper transparent electrode layer is prepared on a transparent substrate using photolithography and magnetron sputtering processes; S3: A copper mesh protective layer is prepared on the surface of the copper mesh using atomic layer deposition (ALD) technology; S4: Fabricate the control circuit layer and complete the electrical connection with the copper mesh electrode; S5: An insulating adapter layer is formed by spin coating and curing on the control circuit layer, and a surface micro-bump structure is created by nanoimprinting. S6: A pressure sensing array is fabricated on the insulating adapter layer by inkjet printing, and a temperature and humidity sensing unit is integrated by patch to form a multimodal sensing layer. S7: The encapsulation layer is combined with the multimodal sensing layer through a vacuum hot-pressing process, and the finished product is obtained after cutting and testing.

[0013] Preferably, the power of the magnetron sputtering deposition of the copper layer is 100-150W, the argon flow rate is 20-30sccm, and the deposition temperature is 80-100℃; the atomic layer deposition temperature is 120-150℃; the vacuum hot pressing temperature is 100-120℃, the pressure is 0.5-1MPa, and the vacuum degree is not higher than 10Pa.

[0014] Compared with the prior art, the beneficial effects of the present invention are: The flexible touch skin of this invention adopts a multi-layer composite structure design, combining excellent flexibility and light transmittance. It can closely conform to the curved surface of a robot without obstructing the visual sensor, adapting to the shape and usage requirements of various robots. The protective layer design effectively improves the environmental tolerance of the electrodes, extending the product's lifespan, while the double-layer electromagnetic shielding structure enhances the signal's anti-interference capability. The multimodal sensing layer enriches the sensing dimensions, enabling simultaneous detection of touch and multiple physical quantities, improving the robot's interaction and environmental adaptability. The overall manufacturing process has high compatibility, facilitating large-scale production and reducing the manufacturing and subsequent maintenance costs of the robot's touch skin. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the flexible touch-sensitive skin structure of the robot of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see Figure 1 The present invention provides a technical solution: a robot flexible touch skin based on a transparent conductive copper mesh, which includes, from bottom to top: a transparent substrate, a metal mesh copper transparent electrode layer, a copper mesh protective layer, a control circuit layer, an insulating adapter layer, a multimodal sensing layer, and an encapsulation layer.

[0018] The transparent substrate is a flexible transparent polymer film used to provide mechanical support for the overall structure and ensure optical transmittance. It is made of flexible transparent polymer material polyimide (PI) or polyethylene terephthalate (PET) with a thickness of 50-100μm. The surface is plasma modified to improve surface energy and interlayer bonding force, ensuring the flexibility and light transmittance of the overall structure, and can be closely attached to the curved parts of the robot.

[0019] The metal mesh copper transparent electrode layer is formed on a transparent substrate, and is composed of orthogonally arranged copper wires forming a capacitive touch matrix for realizing touch signal sensing and transmission. The copper wires are formed on the transparent substrate and are composed of orthogonally arranged copper wires forming a capacitive touch matrix. The copper wires have a purity of not less than 99.9%, a line width of 5-20μm, a spacing of 100-300μm, and a thickness of 20-50nm. They are used to realize touch signal sensing, acquisition, and transmission, and have good light transmittance while ensuring high conductivity.

[0020] The copper mesh protective layer is coated on the surface of the metal mesh copper transparent electrode layer. It is a transparent anti-oxidation film used to protect the copper mesh electrode from environmental corrosion. It is a SiO2-TiO2 composite transparent anti-oxidation film with a thickness of 5-10nm. It is prepared by atomic layer deposition process, completely covering the surface of the copper mesh to form a dense protective layer, which isolates moisture, oxygen and corrosive media, avoids copper electrode oxidation and increased sheet resistance, and improves structural durability.

[0021] The control circuit layer is electrically connected to the metal mesh copper transparent electrode layer and the multimodal sensing layer for signal acquisition, processing, and anti-interference. It is also electrically connected to the metal mesh copper transparent electrode layer and the multimodal sensing layer, and integrates a microcontroller, a signal processing module, a filtering module, and a multimodal signal fusion module. The filtering module uses a double-layer electromagnetic shielding structure made of copper foil and polyimide to suppress electromagnetic interference, stabilize signal transmission, and realize the synchronous processing and output of touch signals and multimodal sensing signals.

[0022] The insulating adapter layer is disposed between the control circuit layer and the multimodal sensing layer. It is a flexible insulating dielectric layer used to isolate the interlayer structure and ensure the stability of the capacitor signal. It is made of polydimethylsiloxane (PDMS) or polyurethane (PU) flexible insulating material with a thickness of 30-50μm and a micro-bump structure on the surface. The micro-bumps have a diameter of 5-10μm and a spacing of 20μm. It is used to isolate the control circuit layer from the upper layer structure, prevent interlayer short circuits and signal crosstalk, and at the same time enhance the interlayer adhesion to ensure the stability of the capacitor signal.

[0023] The multimodal perception layer integrates flexible sensing units to achieve the perception of multiple physical quantities in addition to touch control; it also integrates a distributed flexible pressure sensing array and a temperature and humidity sensing unit, with the pressure sensing array unit spacing of 50-100μm, to achieve pressure perception and temperature and humidity environmental perception, expand the perception dimension of the touch skin, and improve the robot's interaction and environmental adaptability.

[0024] The encapsulation layer is a flexible, transparent, and wear-resistant film used to protect the internal functional layers and improve surface durability. It is made of transparent polyolefin elastomer (POE) or fluororubber, with a thickness of 40-60 μm, and its surface is treated with anti-scratch and anti-fingerprint properties. Its pencil hardness is not less than 3H. This layer protects the internal functional layers and improves the overall structure's wear resistance, weather resistance, and service life.

[0025] A method for preparing a robotic flexible touch-sensitive skin includes the following steps: S1: Prepare a transparent substrate and perform plasma surface modification; prepare a flexible transparent polymer film using a casting process, cut it to the required size, and then perform plasma surface modification treatment in an argon atmosphere to improve the adhesion of the substrate surface and prevent the subsequent functional layers from falling off.

[0026] S2: A metal mesh copper transparent electrode layer is prepared on a transparent substrate using photolithography and magnetron sputtering. Photoresist is uniformly coated on the surface of the transparent substrate, and a mesh pattern mask is formed by ultraviolet exposure and development. A copper layer is deposited using magnetron sputtering with a sputtering power of 100-150W, an argon flow rate of 20-30sccm, and a deposition temperature of 80-100℃. Subsequently, the photoresist is removed, and post-etching and cleaning are performed to obtain a regular metal mesh copper transparent electrode layer.

[0027] S3: A copper mesh protective layer is prepared on the surface of a copper mesh using atomic layer deposition (ALD). The substrate with the copper mesh is placed in an ALD equipment, and a SiO2-TiO2 composite film is deposited at 120-150°C with precursors and reactive gases, so that the surface of the copper wire is uniformly and densely coated to form an antioxidant protective layer.

[0028] S4: Fabricate the control circuit layer and complete the electrical connection with the copper mesh electrode; use flexible circuit board etching process to fabricate the circuit substrate, integrate microcontroller, signal processing module, filtering module and multi-mode signal fusion module, and fabricate copper foil and polyimide double-layer electromagnetic shielding structure in the filtering area; use flexible ribbon cable to realize electrical connection between the control circuit layer and the copper mesh electrode, and perform insulation sealing treatment on the connection point.

[0029] S5: Spin-coating and curing an insulating adapter layer on the control circuit layer to form a micro-bump structure on the surface through nanoimprinting; PDMS or PU insulating material is spin-coated onto the surface of the control circuit layer, and after thermosetting, a micro-bump structure is made on its surface using nanoimprinting process to enhance interlayer bonding and optimize capacitor dielectric performance.

[0030] S6: A pressure sensing array is fabricated on the insulating adapter layer by inkjet printing, and temperature and humidity sensing units are integrated by patch mounting to form a multimodal sensing layer. Graphene / carbon nanotube composite conductive ink is placed in a high-precision inkjet printing device and printed on the surface of the insulating adapter layer according to a preset array pattern to form a distributed flexible pressure sensing array, with the spacing between sensing units controlled at 50-100μm. After printing, the array is placed in an oven for low-temperature curing at 60-80℃ for 30 minutes to ensure the conductive ink is fully formed and its conductivity is stable. Then, using a micro-nano patching process, miniature temperature and humidity sensing units are precisely mounted at the gaps in the pressure sensing array, and electrical connection with the control circuit layer interface module is achieved through conductive silver paste. After the conductive silver paste has cured, the connection points are insulated to complete the overall fabrication of the multimodal sensing layer.

[0031] S7: The encapsulation layer is composited with the multimodal sensing layer through a vacuum hot-pressing process. After cutting and testing, the finished product is obtained. The surface of the encapsulation layer material is pre-treated for scratch resistance and fingerprint resistance, and then covered on top of the multimodal sensing layer. Vacuum hot-pressing is performed under conditions of vacuum degree ≤10Pa, temperature 100-120℃, and pressure 0.5-1MPa, and the pressure is held for 1-2 minutes. After cooling, excess material at the edges is trimmed, and the finished flexible touch skin is obtained after passing performance testing. Specific Implementation

[0032] S1: Preparation and modification of transparent substrate. Polyimide (PI) was selected as the transparent substrate material, and a film with a thickness of 80 μm was formed by casting. The substrate was then subjected to argon plasma treatment at a power of 180 W for 4 min to improve surface adhesion.

[0033] S2: Fabrication of a transparent copper mesh electrode layer: Photoresist with a thickness of approximately 1-2 μm was uniformly coated onto the modified substrate surface. UV lithography was used for exposure and development to form a mesh mask. Subsequently, a copper layer was deposited by magnetron sputtering at a sputtering power of 120 W, an argon flow rate of 25 sccm, and a deposition temperature of 90 °C, resulting in a metal mesh electrode with a copper wire width of 10 μm, a spacing of 200 μm, and a thickness of 30 nm. The electrode layer was then completed after photoresist removal and cleaning.

[0034] S3: Preparation of copper mesh protective layer. The substrate with copper mesh is placed in an atomic layer deposition device. Using titanium tetrachloride and silane as precursors and oxygen as reaction gas, a SiO2-TiO2 composite protective layer is deposited at 130℃ with a thickness controlled at 8nm, so that the surface of the copper wire is uniformly and densely covered.

[0035] S4: Control circuit layer fabrication and connection. The control circuit layer is fabricated using flexible circuit board technology, integrating a microcontroller, signal processing module, filtering module, and multimodal signal fusion module. The filtering module uses copper foil composite polyimide to form a double-layer electromagnetic shielding structure. The control circuit layer is connected to the copper grid electrodes via flexible cables, and the solder joints are insulated and sealed.

[0036] S5: Preparation of the insulating adapter layer. Polydimethylsiloxane (PDMS) was selected as the insulating material and spin-coated onto the surface of the control circuit layer at a speed of 4000 r / min for 45 s. After curing, an insulating layer with a thickness of 40 μm was formed. Microbump structures with a diameter of 8 μm and a spacing of 20 μm were fabricated on its surface by nanoimprinting to enhance the interlayer bonding force.

[0037] S6: Multimodal sensing layer fabrication: A distributed pressure sensing array with an 80μm unit spacing was fabricated by inkjet printing of graphene / carbon nanotube composite conductive ink onto an insulating adapter layer. After printing, the array was cured at 70℃ for 30 minutes. The miniature temperature and humidity sensing units were then mounted into the array gaps using a micro-nano patch process. Conductive silver paste was used to achieve electrical connection with the control circuit. After curing, the connection points were insulated and protected.

[0038] S7: Encapsulation and Finished Product. Transparent polyolefin elastomer (POE) is selected as the encapsulation layer material, with a thickness of 50μm and a scratch-resistant and fingerprint-resistant surface treatment. The encapsulation layer and the multimodal sensing layer are hot-pressed together under vacuum ≤10Pa, temperature 110℃, and pressure 0.8MPa, holding the pressure for 1 minute. After cooling, the edges are trimmed, and the finished product is obtained after passing tests for light transmittance, sheet resistance, touch response, and bending reliability.

[0039] This invention discloses a flexible touch-sensitive skin for robots based on a transparent conductive copper mesh and its fabrication method. Through a collaborative design of a seven-layer composite structure, it solves the problems of rigidity, light transmittance, and limited sensing capabilities inherent in traditional robot touch-sensitive skins. The product uses a transparent conductive copper mesh as its core, combined with protective, insulating, and multimodal sensing functional layers, achieving a combination of flexible curved surface bonding, high optical transmittance, and simultaneous sensing of multiple physical quantities. Simultaneously, optimized fabrication processes ensure tight bonding and stable performance of each layer. This solution balances signal stability, environmental tolerance, and production practicality, and can be widely adapted to various robots in service, industrial collaboration, and medical assistance applications. It provides a reliable touch sensing solution for the intelligent and human-centered upgrade of robots, possessing promising industrial application prospects.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A robotic flexible touch skin based on a transparent conductive copper mesh, characterized in that, From bottom to top, it includes: a transparent substrate, a metal mesh copper transparent electrode layer, a copper mesh protective layer, a control circuit layer, an insulating adapter layer, a multimodal sensing layer, and an encapsulation layer; The transparent substrate is a flexible transparent polymer film, which is used to provide mechanical support for the overall structure and ensure optical transmittance. The metal mesh copper transparent electrode layer is formed on a transparent substrate, and the capacitive touch matrix is ​​composed of orthogonally arranged copper wires to realize touch signal sensing and transmission. The copper mesh protective layer is coated on the surface of the metal mesh copper transparent electrode layer. It is a transparent anti-oxidation film used to protect the copper mesh electrode from environmental corrosion. The control circuit layer is electrically connected to the metal mesh copper transparent electrode layer and the multimodal sensing layer, and is used for signal acquisition, processing and anti-interference. The insulating adapter layer is disposed between the control circuit layer and the multimodal sensing layer. It is a flexible insulating dielectric layer used to isolate the interlayer structure and ensure the stability of the capacitor signal. The multimodal sensing layer integrates flexible sensing units to realize the sensing of multiple physical quantities in addition to touch control; The encapsulation layer is a flexible, transparent, and wear-resistant film used to protect the internal functional layers and improve surface durability.

2. The robotic flexible touch skin based on a transparent conductive copper mesh according to claim 1, characterized in that: The transparent substrate is made of polyimide or polyethylene terephthalate with a thickness of 50-100μm and the surface is plasma modified.

3. The robotic flexible touch skin based on a transparent conductive copper mesh according to claim 1, characterized in that: The copper wires of the metal mesh copper transparent electrode layer have a wire width of 5-20μm, a spacing of 100-300μm, a thickness of 20-50nm, and a copper wire purity of not less than 99.9%.

4. The robotic flexible touch skin based on a transparent conductive copper mesh according to claim 1, characterized in that: The copper mesh protective layer is a SiO2-TiO2 composite film with a thickness of 5-10 nm, which is prepared by atomic layer deposition and completely covers the surface of the copper wire.

5. The robotic flexible touch skin based on a transparent conductive copper mesh according to claim 1, characterized in that: The control circuit layer includes a microcontroller, a signal processing module, a filtering module, and a multimodal signal fusion module. The filtering module adopts a double-layer electromagnetic shielding structure composed of copper foil and polyimide.

6. The robotic flexible touch skin based on a transparent conductive copper mesh according to claim 1, characterized in that: The insulating adapter layer is made of polydimethylsiloxane or polyurethane material, with a thickness of 30-50μm and a micro-bump structure on the surface, with a micro-bump diameter of 5-10μm and a spacing of 20μm.

7. The robotic flexible touch skin based on a transparent conductive copper mesh according to claim 1, characterized in that: The multimodal sensing layer includes a distributed flexible pressure sensing array and temperature and humidity sensing units, with the pressure sensing array units spaced 50-100 μm apart.

8. The robotic flexible touch skin based on a transparent conductive copper mesh according to claim 1, characterized in that: The encapsulation layer is made of transparent polyolefin elastomer or fluororubber material, with a thickness of 40-60μm. The surface is treated with anti-scratch and anti-fingerprint properties, and the pencil hardness is not less than 3H.

9. A method for preparing a robotic flexible touch-sensitive skin according to any one of claims 1-8, characterized in that, Includes the following steps: S1: Prepare a transparent substrate and perform plasma surface modification; S2: A metal mesh copper transparent electrode layer is prepared on a transparent substrate using photolithography and magnetron sputtering processes; S3: A copper mesh protective layer is prepared on the surface of the copper mesh using atomic layer deposition (ALD) technology; S4: Fabricate the control circuit layer and complete the electrical connection with the copper mesh electrode; S5: An insulating adapter layer is formed by spin coating and curing on the control circuit layer, and a surface micro-bump structure is created by nanoimprinting. S6: A pressure sensing array is fabricated on the insulating adapter layer by inkjet printing, and a temperature and humidity sensing unit is integrated by patch to form a multimodal sensing layer. S7: The encapsulation layer is combined with the multimodal sensing layer through a vacuum hot-pressing process, and the finished product is obtained after cutting and testing.

10. The preparation method according to claim 9, characterized in that: The power of the magnetron sputtering deposition of the copper layer is 100-150W, the argon flow rate is 20-30sccm, and the deposition temperature is 80-100℃; the atomic layer deposition temperature is 120-150℃; the vacuum hot pressing temperature is 100-120℃, the pressure is 0.5-1MPa, and the vacuum degree is not higher than 10Pa.

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