A method for manufacturing a transparent conductive circuit on a curved substrate

Abstract

The application provides a manufacturing method of a transparent conductive circuit of a curved substrate, which comprises the following steps: cleaning and pretreating the substrate, coating a thin and uniform sacrificial layer solution on the surface of the substrate, and solidifying the sacrificial layer; printing a conductive circuit pattern on the surface of the substrate according to a preset pattern shape by using an electric field driven jet deposition 3D printer, and performing sintering and solidification treatment on the printed sample; placing a substrate such as glass into a water solution of a sacrificial layer substrate at a predetermined position, so that the conductive pattern is locally contacted with a to-be-transferred curved surface to form a positioning point, thereby improving the transfer precision; dissolving and removing the sacrificial layer by using the water solution, and transferring the silver grid circuit to the to-be-transferred curved surface under the action of gravity; using the water flow when the curved substrate is separated from the water surface to drive the grid circuit to flatten along the curved surface; taking out and drying the curved substrate; and selectively spraying an adhesive on the curved substrate, thereby completing the manufacturing of the curved substrate circuit. The application can realize the low-cost and large-scale manufacturing of the high-performance transparent conductive circuit of the curved substrate, and has the advantages of simple process steps, environmental protection, harmlessness and low manufacturing cost.

Description

Technical Field

[0001] This invention belongs to the field of transparent electronics manufacturing, and specifically relates to a method for manufacturing a transparent conductive circuit on a curved substrate. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of electronic information technology, curved electronics are playing an increasingly important role in aerospace, flexible transparent displays, wearable devices, smart windows, transparent electric heating, and electromagnetic shielding. Traditional electronic circuit board manufacturing processes, such as thermal transfer printing and photosensitive wet film printing, can only achieve 2D or 2.5D circuit manufacturing. The manufacturing process requires subtractive manufacturing processes such as etching, which are complex, have high equipment costs, and generate waste liquid and exhaust gas that pollute the environment. Moreover, circuit boards are mostly made of silicon-based materials, making them difficult to bend and deform, and incompatible with complex curved surfaces, making it difficult to manufacture flexible curved electronic circuits. To meet the urgent needs of various fields for curved electronics, curved electronics manufacturing technology has emerged. Existing curved electronics manufacturing processes are mainly divided into two routes: one is to print electronic circuits on curved substrates through direct printing, such as aerosol jetting technology, 3D printing direct writing technology, and electrohydrodynamic printing technology; the other route is to transfer pre-manufactured electronic circuits to curved substrates through transfer methods, such as water transfer printing technology and thermoforming technology.

[0004] Aerosol jetting technology, pioneered by Optomec, uses pneumatic or ultrasonic means to refine printing materials into aerosols, which are then propelled onto a substrate by airflow, enabling the deposition and printing of materials at the micro- and nano-scale. The advantages of aerosol jetting technology include non-contact printing, suitability for planar and flexible substrates, but to achieve conformal circuit printing on curved substrates, the aerosol jetting printing device needs to be combined with a five-axis machine tool. This results in expensive machinery, the ability to print only one type of material at a time, and poor edge roughness of the manufactured electronic circuits. Furthermore, post-processing is difficult if the curved substrate has a complex surface shape. Lewis et al. used 3D direct-write printing technology to directly fabricate curved circuits on hemispherical surfaces. While 3D direct-write printing can print complex circuits, its efficiency is low, and the printing accuracy is limited, making high-precision printing difficult. Zhang Libing et al. proposed a method combining electrohydrodynamic jetting printing with a five-axis machine tool to print curved circuits. However, the real-time change in the distance between the printing nozzle and the substrate during printing leads to uneven electric field distribution, affecting the consistency and continuity of the printing process. In summary, there are still many problems with manufacturing conformal circuits on curved substrates through direct printing, such as: 1. It requires combining the printing device with a five-axis machine tool, resulting in high equipment costs; 2. Post-processing of the path is difficult, making it hard to directly print circuits on complex shaped surfaces such as concave surfaces with large curvature; 3. Limited printing accuracy makes it difficult to manufacture high-precision transparent conductive circuits on curved substrates.

[0005] The second technical approach typically involves thermoforming and water transfer printing. The thermoforming process first manufactures the circuit structure using PCB fabrication techniques, laser processing, etc., then transfers the circuit structure to a thermoplastic film, and finally uses thermoforming to bond the circuit structure and the thermoplastic film to the surface of a three-dimensional object. This method struggles to achieve complete bonding between the circuit structure and curved surfaces, and the thermoforming process is prone to circuit peeling, making it unsuitable for manufacturing high-precision transparent conductive circuits on curved substrates.

[0006] Water transfer printing technology is further divided into water-marked transfer printing and water-draping transfer printing. Water-marked transfer printing involves printing electronic circuitry onto a transfer film. After separating the base paper, the transfer film, along with the electronic circuitry, is stretched onto the surface of a curved substrate. After drying, the transfer is complete. Similar to thermoforming, water-marked transfer printing has the advantage of not requiring a heating process and only requiring an aqueous solution. However, it has the disadvantage of having a transfer film between the curved substrate and the electronic circuitry, requiring the film to be stretched onto the curved substrate during transfer. This makes the operation more difficult, less repeatable, and difficult to scale up. Furthermore, the transfer film affects light transmittance and refractive index, making it unsuitable for transparent displays. Water-draping transfer printing involves printing a pattern onto a water-soluble substrate such as a PVA film, then laying it flat in water. After the PVA dissolves, the pattern floats on the surface of the aqueous solution. The curved surface is then transferred through the floating pattern under surface tension. Water-based transfer printing can directly transfer patterns onto curved substrates without an adhesive layer. However, the stress and strain generated during the dissolution process of the transfer film, as well as the distortion and breakage of the circuit patterns upon transfer to the curved substrate, make it difficult to manufacture high-resolution electronic circuits. Currently, the main methods for printing patterns on transfer film paper include screen printing, offset printing, and inkjet printing. Screen printing and offset printing produce circuit patterns with relatively low resolution. While inkjet printing can achieve high-resolution printing, it suffers from limitations in ink viscosity, nozzle clogging, and poor conductivity of the circuit patterns. In summary, the second technical solution generally suffers from problems such as easy distortion of circuit patterns and limited wire resolution during the transfer process. Summary of the Invention

[0007] To address the aforementioned problems, this invention proposes a method for manufacturing transparent conductive circuits on curved substrates. First, a high-viscosity conductive paste is printed onto a sacrificial layer substrate to form a two-dimensional transparent conductive circuit pattern. Then, by dissolving the sacrificial layer substrate, gravity transfers the transparent circuit to the curved substrate. Finally, an adhesive layer can be selectively sprayed to enhance the adhesion between the conductive circuit and the curved substrate. This invention enables low-cost, large-scale manufacturing of high-performance transparent conductive circuits on curved substrates, and also offers advantages such as simple process steps, environmentally friendly production, and low manufacturing costs.

[0008] According to some embodiments, the present invention adopts the following technical solution:

[0009] A method for manufacturing a transparent conductive circuit on a curved substrate includes the following steps:

[0010] (1) The substrate is cleaned and pretreated, and then a thin and uniform sacrificial layer solution is coated on the substrate surface and the sacrificial layer is cured to complete the preparation of the printed substrate.

[0011] (2) Using an electric field to drive a jet deposition 3D printer to print conductive circuit patterns on the substrate surface according to a preset pattern shape, and then sintering and curing the printed sample to complete the printing of the conductive circuit pattern.

[0012] (3) Place the substrate such as glass into the predetermined position of the aqueous solution that can dissolve the sacrificial layer substrate, so that the conductive pattern makes local contact with the surface to be transferred to form a positioning point to improve the transfer accuracy. The sacrificial layer is removed by dissolving in the aqueous solution. The silver grid circuit will be transferred to the surface to be transferred under its own gravity. When the surface substrate is lifted off the water surface, the water flows down along the edge of the surface and drives the grid circuit to flatten along the surface to eliminate wrinkles. Take out and dry the surface substrate. Selectively spray adhesive on the surface substrate to complete the manufacturing of the surface substrate circuit.

[0013] As an alternative implementation, the substrate in step (1) includes a rigid substrate and a flexible substrate. The rigid substrate includes, but is not limited to, glass sheets, silicon wafers and acrylic sheets, and the flexible substrate includes, but is not limited to, PET films and PI films.

[0014] As an alternative implementation, the substrate cleaning pretreatment process in step (1) includes placing the substrate in an isopropanol solution for ultrasonic treatment, then placing it in deionized water for ultrasonic cleaning to remove residual isopropanol solution, and finally drying the substrate with inert gas.

[0015] As an alternative implementation, the sacrificial layer solution in step (1) includes, but is not limited to, polyvinyl alcohol and cellulose solutions;

[0016] The typical preparation process of cellulose solution includes: heating a certain amount of deionized water to a set temperature, taking a certain amount of hydroxypropyl methylcellulose powder and mixing it into the just-heated deionized water, stirring at room temperature for a period of time, and then placing it in a vacuum drying oven to remove air bubbles.

[0017] The typical preparation process of polyvinyl alcohol solution is as follows: heat a certain amount of deionized water to a set temperature, take a certain amount of polyvinyl alcohol powder and mix it into the freshly heated deionized water, stir under heating conditions until the polyvinyl alcohol powder is completely dissolved, and then remove the air bubbles by vacuuming.

[0018] As an alternative implementation, the coating method in step (1) includes, but is not limited to, spin coating, dip coating, 3D printing, etc.

[0019] As an alternative implementation, the curing temperature range of the sacrificial layer in step (1) is 30-150 degrees Celsius, and the curing time is 2-60 minutes.

[0020] As an alternative implementation, the slurry used for printing in step (2) includes, but is not limited to, nano-silver conductive slurry, 1-nanometer copper conductive slurry and nano-silver wire conductive slurry, with a viscosity range of 1000-80000cps.

[0021] Because of the use of high-solids-content and high-viscosity conductive paste, the printed metal mesh has a certain rigidity. After the sacrificial layer substrate dissolves, it can form a self-supporting mesh that can exist independently in the solution, effectively preventing pattern distortion and other issues that may occur during pattern transfer.

[0022] As an alternative implementation, the conductive circuit pattern in step (2) includes, but is not limited to, grids, wire grids, rhombuses and other designed circuit structures. The wire width, period, shape and arrangement can be adjusted by adjusting the printing parameters (printing speed, printing voltage, back pressure, etc.) according to actual needs.

[0023] As an alternative implementation, the sintering and curing temperature range for the sample with the printed conductive circuit pattern in step (2) is 60-150 degrees Celsius, and the curing time is 15-120 minutes.

[0024] As an alternative implementation, the substrate material in step (3) includes, but is not limited to, ceramics, plastics, glass and silicone; the surface shape includes, but is not limited to, developable surfaces and non-developable surfaces.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The process of this invention is simple, with no special requirements for the printing substrate material, overcoming the drawback of water transfer printing which requires transfer film paper. The manufacturing process is green and environmentally friendly, generating no waste gas or wastewater pollutants. Dissolving the sacrificial layer substrate only requires an aqueous solution, and the material is readily available. Using 3D printing to print conductive patterns allows for 100% utilization of the conductive paste. This invention facilitates the large-area, low-cost, mass production of high-performance transparent conductive circuits on curved substrates.

[0027] This invention uses an electric field-driven jet deposition 3D printing method to manufacture conductive patterns, overcoming the limitations of inkjet printing, which can only print low-viscosity pastes, and the low resolution of screen printing wires. It can achieve high-precision, high-resolution printing of high-viscosity conductive pastes. While ensuring conductivity, the wire precision can reach up to 1 micrometer, which is almost invisible to the human eye, thus realizing the manufacture of transparent conductive circuit patterns.

[0028] The transparent conductive circuit pattern printed in this invention uses a high-viscosity conductive paste, which gives the circuit pattern a certain rigidity after sintering and curing. This allows for the creation of a "self-supporting" grid, meaning that the circuit pattern can remain independently and completely in water after dissolving in the water-soluble polymer layer. Figure 9As shown, it is possible to manufacture transparent conductive circuits on inner curved substrates. The self-supporting mesh can be freely attached to the inner surface of the curved substrate, breaking through the bottleneck of current technology that makes it difficult to manufacture high-resolution conductive circuits on inner curved surfaces.

[0029] This invention can truly realize the large-area manufacturing of transparent conductive circuits on curved substrates, with the conductive circuit area limited only by the worktable travel and the size of the water tank.

[0030] This invention has a wide range of applications. The curved substrate transparent conductive circuit can be applied to wearable devices, smart windows, transparent electric heating, flexible transparent displays, electromagnetic shielding, OLEDs and other fields.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0033] Figure 1 This is a typical manufacturing process flow diagram for a transparent conductive circuit on the outer surface of a curved substrate.

[0034] Figure 2 Typical manufacturing process flow diagram for transparent conductive circuits on the inner surface of curved substrates

[0035] Figure 3 This is a physical illustration of a circuit pattern manufactured using the method of Example 1 (inner surface of a hemispherical curved surface).

[0036] Figure 4 The heating cloud diagram shows the highest temperature achievable by the sample manufactured in Example 1 under different applied voltages. The samples were subjected to DC voltages ranging from 2-8V, and the highest temperatures reached were 37.7℃, 43℃, 50.9℃, 61℃, 72.3℃, 84.3℃, and 94.4℃, respectively.

[0037] Figure 5 This is a defrosting test result of the sample manufactured in Example 1. At 0 seconds, the circuit is connected to an 8V DC voltage. At this time, the surface of the hemispherical surface is covered with white frost. As time goes by, the white frost gradually melts. At 1 minute and 40 seconds, the white frost is completely removed, and the hemispherical surface returns to a transparent state.

[0038] Figure 6 A physical diagram of an antenna structure fabricated on a hemispherical outer surface.

[0039] Figure 7 This is a schematic diagram of an irregular curved surface;

[0040] Figure 8A transparent conductive circuit on the outer surface of a curved substrate;

[0041] Figure 9 This is a physical diagram of a self-supporting mesh. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0044] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0045] Example 1: Circuit patterns are fabricated on the inner surface of a hemispherical outer casing for use in transparent electric heating applications. The specific manufacturing process is detailed below. Figure 2 .

[0046] Step 1: Prepare the printing substrate

[0047] (1) Select PET film as flexible substrate. First, place the PET film in isopropanol solution for ultrasonic cleaning for 5 min, then place it in deionized water for ultrasonic cleaning for 5 min to remove residual isopropanol solution, and finally blow it dry with nitrogen.

[0048] (2) The sacrificial layer solution is a cellulose solution. The preparation process of the cellulose solution is as follows: heat 100 ml of deionized water to 100 degrees, take 5 g of hydroxypropyl methylcellulose powder (type II, viscosity 400 mPa.s) and mix it into the freshly heated deionized water. Stir at room temperature for 10 minutes, and then put it into a vacuum drying oven to remove air bubbles.

[0049] (3) A thin and uniform layer of cellulose solution was spin-coated onto the surface of the PET film using a spin coater. The sample was placed in a heating chamber and heated at 80°C for 20 minutes to complete the curing of the cellulose.

[0050] Step 2: Print the conductive circuit pattern

[0051] (1) In this embodiment, the conductive circuit pattern is a grid structure with an area of ​​60×60mm and a period of 1mm. The printing paste is a nano conductive silver paste (viscosity 30000cp, silver content >90%) prepared in the laboratory, and the printing nozzle inner diameter is 200μm.

[0052] (2) After setting the printing parameters (printing height 0.25mm, printing voltage 900V, printing air pressure 180Kpa, table movement speed 30mm / s), run the printing program. The printed wire width is approximately 20μm. Figure 2 As shown in (b).

[0053] (3) After the program finishes running, the sample is removed from the workbench and placed in a drying oven at 130 degrees Celsius for sintering for 30 minutes. This enhances the conductivity of the circuit pattern while also improving its rigidity. Figure 2 As shown in (c).

[0054] Step 3: Transfer the circuit pattern to the inner surface of the hemispherical curved substrate.

[0055] (1) In this embodiment, a hemispherical surveillance camera housing with an outer diameter of 82mm is used as the curved base.

[0056] (2) Clamp the sintered sample with a fixture and bend the PET film appropriately according to the curvature of the hemispherical curved surface base so that the conductive grid structure can be attached to the inner curved surface.

[0057] (3) The hemispherical curved substrate is placed on the water tank base and clamped using a fixture. The curved sample is also placed in the water tank. The PET substrate is placed in the predetermined position so that the conductive silver grid makes partial contact with the inner curved surface to be transferred to improve positioning accuracy. While the sacrificial layer dissolves, the grid pattern adheres to the inner surface of the curved substrate under the action of gravity. The curved substrate can be lifted uniformly from bottom to top. When it leaves the water surface, the hemispherical curved substrate can be tilted appropriately. The flow of water is used to drive the grid circuit to flatten along the curved surface. Finally, the curved substrate is removed and dried. If necessary, an adhesive such as varnish or acrylic resin can be sprayed on. The final manufactured inner curved circuit sample is as follows: Figure 3 As shown, the measured resistance is approximately 4.6 ohms.

[0058] Example 1: By manufacturing conductive circuits on the inner surface of a hemispherical outer casing, defrosting and defogging of surveillance cameras can be achieved. Figure 4 The highest temperatures reached by applying DC voltages of 2-8V to the prototypes were 37.7℃, 43℃, 50.9℃, 61℃, 72.3℃, 84.3℃, and 94.4℃, respectively. Figure 5 This is a picture showing the effect of defrosting.

[0059] Example 2: A circuit pattern is fabricated on the outer surface of the hemispherical outer casing to realize the fabrication of the antenna circuit on a curved substrate, such as... Figure 1 As shown.

[0060] Step 1: Prepare the printing substrate

[0061] (1) Select high-quality float glass as a rigid substrate. First, place the high-quality float glass in isopropanol solution for ultrasonic cleaning for 5 min, then place it in deionized water for ultrasonic cleaning for 5 min, and finally blow it dry with nitrogen.

[0062] (2) The sacrificial layer solution is a cellulose solution. The preparation process of the cellulose solution is as follows: heat 100 ml of deionized water to 100 degrees, take 5 g of hydroxypropyl methylcellulose powder (type II, viscosity 400 mPa.s) and mix it into the freshly heated deionized water. Stir at room temperature for 10 minutes, and then put it into a vacuum drying oven to remove air bubbles.

[0063] Step 2: Print the conductive circuit pattern

[0064] (1) The conductive circuit pattern in this embodiment is an antenna circuit. The printing paste is a nano conductive silver paste (viscosity 30000cp, silver content >90%) prepared in the laboratory, and the inner diameter of the printing nozzle is 250μm.

[0065] (2) After setting the printing parameters (printing height 0.25mm, printing voltage 850V, printing air pressure 160Kpa, table movement speed 40mm / s), run the printing program.

[0066] (3) After the program is completed, the sample is removed from the workbench and placed in a drying oven at 140 degrees Celsius for sintering for 25 minutes. This enhances the conductivity of the circuit pattern and also improves its rigidity.

[0067] Step 3: Transfer circuit pattern

[0068] (1) In this embodiment, a hemispherical cover with an outer diameter of 82mm is used as the curved surface base.

[0069] (2) A hemispherical curved substrate is placed on a water tank base and clamped using a fixture. The sintered sample is then clamped and placed above the outer surface of the hemispherical substrate. A glass substrate is placed in a predetermined position, allowing the conductive silver grid to partially contact the inner curved surface to be transferred, thus improving positioning accuracy. While the sacrificial layer dissolves in the aqueous solution, the circuit pattern sinks and adheres to the outer surface of the curved substrate under gravity. The curved substrate is then lifted uniformly from bottom to top. During the lifting process, the grid adheres to the surface of the curved structure under water pressure. When it leaves the water surface, the water flows down along the edge of the curved surface, causing the grid circuit to flatten along the curved surface, completing the high-precision curved surface transfer of the microcircuit. Finally, the curved substrate is removed and dried. The final manufactured sample is shown below. Figure 6 As shown.

[0070] Example 3: Manufacturing circuit patterns on irregular surfaces, the circuit patterns being paper-cut structures, such as... Figure 7 As shown.

[0071] Step 1: Prepare the printing substrate

[0072] (1) The typical preparation process of PVA solution is as follows: heat 100 ml of deionized water to 100 degrees, take 10 g of polyvinyl alcohol powder and mix it into the heated deionized water, stir under heating conditions until the polyvinyl alcohol powder is completely dissolved, and then put it into a vacuum drying oven to remove air bubbles.

[0073] (2) A thin and uniform PVA solution was printed on the surface of ordinary glass using 3D printing. The sample was placed in a vacuum drying oven and heated at 80°C for 30 minutes to complete the PVA curing.

[0074] Step 2: Print the conductive circuit pattern

[0075] (1) The conductive circuit pattern in this embodiment is a paper-cut structure, including wavy, fractal, and island bridge structures, which can improve the tensile properties of the conductive circuit. This embodiment uses a wavy structure. The printing paste selected is Zhongke Natong TL-20E nano conductive silver paste, and a Musashi needle with an inner diameter of 200 micrometers is used.

[0076] (2) After setting the printing parameters (printing height 0.3mm, printing voltage 950V, printing air pressure 200Kpa, table movement speed 30mm / s), run the printing program.

[0077] (3) After the program runs, the sample is removed from the workbench and placed in a vacuum drying oven at 135 degrees Celsius for sintering for 30 minutes. The conductive circuit pattern is then completed.

[0078] Step 3: Transfer the circuit pattern to the curved substrate

[0079] (1) In this embodiment, an irregular curved surface is used as the curved surface substrate. The irregular curved surface substrate is placed on the water tank base and clamped with a fixture. The sintered sample is clamped and placed above the hemispherical outer surface. The glass substrate is placed in a predetermined position so that the conductive silver grid makes partial contact with the inner curved surface to be transferred to improve the positioning accuracy. While the sacrificial layer dissolves, the circuit pattern falls and adheres to the outer surface of the curved surface substrate under the action of gravity. The curved surface substrate is lifted uniformly from bottom to top. During the lifting process, the grid will adhere to the surface of the curved structure. When it leaves the water surface, the water flows down along the edge of the curved surface and drives the grid circuit to flatten along the curved surface, completing the curved surface transfer of the micro-circuit with high positioning accuracy. The curved surface substrate is removed, dried, and a layer of varnish is sprayed to enhance the adhesion of the conductive pattern.

[0080] Example 4: A circuit pattern is manufactured on the inner surface of the hemispherical outer cover, which can be applied to the field of electromagnetic shielding.

[0081] Step 1: Prepare the printing substrate

[0082] (1) Select float glass as a rigid substrate, place the float glass in isopropanol solution and deionized water respectively for ultrasonic cleaning for 5 min, and finally dry the float glass with inert gas.

[0083] (2) The sacrificial layer solution is a cellulose solution. The preparation process of the cellulose solution is as follows: heat 100 ml of deionized water to 100 degrees, take 5 g of hydroxypropyl methylcellulose powder (type II, viscosity 400 mPa.s) and mix it into the freshly heated deionized water. Stir at room temperature for 10 minutes, and then put it into a vacuum drying oven to remove air bubbles.

[0084] (3) A thin, uniform layer of cellulose solution was spin-coated onto the surface of float glass using a spin coater. The sample was then placed in a heating chamber and heated at 80°C for 20 minutes to complete the cellulose curing.

[0085] Step 2: Print the conductive circuit pattern, such as Figure 8 As shown.

[0086] (1) In this embodiment, the conductive circuit pattern is a grid structure with an area of ​​70×70mm and a period of 0.5mm. The printing paste is a nano conductive silver paste (viscosity 30000cp, silver content >90%) prepared in-house, and the printing nozzle has an inner diameter of 200μm.

[0087] (2) After setting the printing parameters, run the printing program and the conductive circuit is printed.

[0088] (3) After the program is completed, remove the sample from the workbench and place it in a drying oven at 130 degrees Celsius for sintering for 30 minutes.

[0089] Step 3: Transfer the circuit pattern to the inner surface of the hemispherical curved substrate.

[0090] (1) In this embodiment, a hemispherical outer cover with an outer diameter of 100mm is used as the curved surface base.

[0091] (2) The hemispherical curved substrate is placed on the water tank base and clamped with a fixture. The sintered sample is clamped and placed above the outer surface of the hemispherical surface. While the sacrificial layer dissolves in the aqueous solution, the circuit pattern sinks and adheres to the outer surface of the curved substrate under the action of gravity. The curved substrate is lifted uniformly from bottom to top. The hemispherical outer curved substrate can be lifted uniformly from bottom to top. When it leaves the water surface, the curved substrate can be tilted at an appropriate angle. The flow of water is used to drive the grid circuit to flatten along the curved surface, completing the high positioning accuracy curved surface transfer of the micro-circuit. Finally, the curved substrate is removed and dried. The hemispherical inner curved surface circuit that can be used for electromagnetic shielding is now complete.

[0092] It should be noted that, due to the use of high-viscosity conductive paste, the transparent conductive circuit pattern possesses a certain rigidity after sintering and curing, enabling the creation of a "self-supporting" grid. This means that after the circuit pattern dissolves in the water-soluble polymer layer, it can remain independently and completely in water. Figure 9 As shown, the self-supporting mesh can remain independently and completely in the liquid solution. In the figure, the self-supporting mesh goes through an unfolded state, a wrinkled state, and then an unfolded state again, without any damage to the mesh during this process.

[0093] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for manufacturing a transparent conductive circuit on a curved substrate, characterized in that, Includes the following steps: (1) The first substrate is cleaned and pretreated, and then a thin and uniform sacrificial layer solution is coated on the surface of the first substrate and the sacrificial layer is cured to complete the preparation of the printed substrate. (2) Using an electric field to drive a jet deposition 3D printer to print conductive circuit patterns on the substrate surface according to the preset pattern shape, the printed sample is sintered and cured to complete the printing of conductive circuit patterns. High solid content and high viscosity conductive paste is used. The printed metal mesh has a certain rigidity and forms a self-supporting mesh after the sacrificial layer dissolves, which exists independently in the solution. (3) Place the substrate at a predetermined position in the aqueous solution that can dissolve the sacrificial layer, so that the conductive circuit pattern makes local contact with the surface to be transferred to form a positioning point. The sacrificial layer is removed by dissolving the aqueous solution. The conductive circuit pattern will be transferred to the surface to be transferred under its own gravity. When the surface substrate is removed from the water surface, the water flows down along the edge of the surface and drives the grid circuit to flatten along the surface to eliminate wrinkles. Remove and dry the surface substrate. Selectively spray adhesive on the surface substrate to complete the manufacturing of the surface substrate circuit.

2. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 1, characterized in that, In step (1), the first substrate includes a rigid substrate and a flexible substrate. The rigid substrate includes, but is not limited to, glass sheets, silicon wafers and acrylic sheets, and the flexible substrate includes, but is not limited to, PET films and PI films.

3. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 1, characterized in that, The first substrate cleaning pretreatment process in step (1) includes placing the first substrate in an isopropanol solution for ultrasonic treatment, then placing it in deionized water for ultrasonic cleaning to remove residual isopropanol solution, and finally drying the first substrate with inert gas.

4. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 1, characterized in that, The sacrificial layer solution in step (1) includes, but is not limited to, polyvinyl alcohol and cellulose solutions.

5. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 4, characterized in that, cellulose The solution preparation process includes: heating a certain amount of deionized water to a set temperature, taking a certain amount of hydroxypropyl methylcellulose powder and mixing it into the just-heated deionized water, stirring at room temperature for a period of time, and then placing it in a vacuum drying oven to remove air bubbles. The preparation process of polyvinyl alcohol solution is as follows: heat a certain amount of deionized water to a set temperature, take a certain amount of polyvinyl alcohol powder and mix it into the freshly heated deionized water, stir under heating conditions until the polyvinyl alcohol powder is completely dissolved, and then vacuum it to remove air bubbles.

6. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 1, characterized in that, The coating methods in step (1) include, but are not limited to, spin coating, dip coating and 3D printing. Alternatively, in step (1), the curing temperature range of the sacrificial layer is 30-150 degrees Celsius, and the curing time is 2-60 minutes.

7. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 1, characterized in that, The printing paste used in step (2) includes, but is not limited to, nano-silver conductive paste, nano-copper conductive paste and nano-silver wire conductive paste, with a viscosity range of 1000-80000cps.

8. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 1, characterized in that, The conductive circuit pattern in step (2) includes, but is not limited to, grid, wire grid, and diamond circuit structure. The printing parameters are adjusted according to actual needs to adjust the wire width, period, shape and arrangement.

9. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 1, characterized in that, In step (2), the sintering and curing temperature range for the sample with the printed conductive circuit pattern is 60-150 degrees Celsius, and the curing time is 15-120 minutes.

10. The method for manufacturing a transparent conductive circuit on a curved substrate as described in claim 1, characterized in that, In step (3), the substrate material of the curved surface includes, but is not limited to, ceramic, plastic, glass and silicone; the curved surface shape includes, but is not limited to, unfoldable curved surfaces and non-unfoldable curved surfaces.

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