Transparent film antenna of composite conducting layer and manufacturing method thereof

Abstract

The invention discloses a transparent film antenna with a composite conductive layer and a manufacturing method thereof, the transparent film antenna comprises a transparent base material, the transparent base material is provided with the composite conductive layer, the composite conductive layer is patterned through an etching process to form an antenna pattern, and the composite conductive layer is jointly formed by a metal grid and a graphene layer covering the transparent base material; the graphene layer is tightly combined with the surface of the metal grid through a spray printing process; a feeding point of the antenna pattern is provided with a bonding pad formed by conductive silver paste; through the composite conductive layer structure of the metal grid and the graphene, the unification of high performance and high transparency is realized on the material level, and through the digital manufacturing process of spray printing and synchronous etching, the unification of high efficiency and high flexibility is realized on the method level. The problem that in the prior art, flexibility, optical performance, conductivity and design iteration efficiency of a transparent antenna are difficult to consider at the same time is solved.

Description

Technical Field

[0001] This invention relates to the technical field of thin-film antennas, specifically to a transparent thin-film antenna with a composite conductive layer and its manufacturing method. Background Technology

[0002] As a key component of wireless communication systems, antennas are constantly evolving in form and integration as electronic devices become more intelligent, transparent, and aesthetically pleasing. In emerging application scenarios such as smart shop windows, transparent displays, and automotive windshield antennas, traditional opaque metal antennas are unsuitable due to visual obstruction. To address this, transparent thin-film antennas have emerged, whose core technology lies in using transparent conductive materials to achieve radio frequency functionality while maintaining high visual transparency.

[0003] The mainstream transparent thin-film antenna technologies are mainly divided into two categories. The first category is based on a single transparent conductive material, such as indium tin oxide or metal mesh. Indium tin oxide thin films have problems such as high brittleness, poor flexibility, and high cost. While metal mesh technology has excellent conductivity, it will produce optical diffraction due to the periodic mesh structure at the microscopic level, and form visible moiré patterns or mesh appearance at the macroscopic level, affecting the uniformity of the display effect. Moreover, under the requirement of pursuing extremely high transparency, the reduction of mesh density will lead to an increase in sheet resistance, which restricts the antenna radiation efficiency.

[0004] The second category is based on complex patterning processes, such as nanoimprinting, microcontact printing, or laser direct writing combined with photolithography. Although these processes can achieve high-precision patterns, their patterning process heavily relies on high-precision physical molds, such as nickel plates, photomasks, or complex multi-step photolithography processes, such as dry film coating, exposure, and development. When antenna design needs iterative optimization during the R&D stage, any minor pattern modification means that the entire mold must be remade or all photolithography steps must be re-executed, which not only causes huge time and economic costs, but also seriously slows down the product development progress from design to finalization. Summary of the Invention

[0005] The purpose of this invention is to provide a transparent thin-film antenna with a composite conductive layer and its manufacturing method, so as to solve the problem that it is difficult to balance flexibility, optical performance, conductivity and design iteration efficiency in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a transparent thin-film antenna with a composite conductive layer, comprising a transparent substrate, wherein a composite conductive layer is disposed on the transparent substrate, the composite conductive layer is patterned by an etching process to form an antenna pattern, and the composite conductive layer is composed of a metal mesh and a graphene layer covering the transparent substrate. The metal mesh has a line width of ≤5μm, the graphene layer has a thickness of ≤200nm, and the graphene layer is tightly bonded to the surface of the metal mesh through a spray printing process. The antenna pattern has a feed point with a pad made of conductive silver paste; the antenna pattern is covered with an optical adhesive protective layer, and the optical adhesive protective layer has windows that expose the pads.

[0007] Preferably, the metal mesh and the graphene layer form a complementary two-dimensional conductive network within the patterned antenna pattern area. The metal mesh provides the main current path, and the graphene layer fills the mesh gaps and forms a continuous two-dimensional conductive film.

[0008] Preferably, the graphene layer is formed by printing and curing graphene ink with a concentration of less than 5%, and the sheet resistance of the graphene layer is in the range of 100-1000 Ω / sq.

[0009] Preferably, the metal mesh has a mesh shape of rhombus, square or hexagon, and the period of the metal mesh is 50-500μm.

[0010] Preferably, the absolute value of the difference between the refractive index of the optical adhesive protective layer and the refractive index of the transparent substrate is ≤0.03, and the thickness of the optical adhesive protective layer is 10-50μm.

[0011] Preferably, the transparent substrate is a PET, COP, or CPI film, the thickness of the transparent substrate is 25-100μm, and the metal material of the metal mesh is copper, silver, or gold.

[0012] A method for manufacturing a transparent thin-film antenna with a composite conductive layer, the method comprising the following steps: S1: Provides a universal transparent substrate metal mesh, with the transparent substrate having a full-surface metal mesh; S2: Using a spray printing process, low-concentration graphene ink is printed on the surface of a metal grid according to a preset antenna pattern area. After curing, a graphene layer is formed, thus obtaining a film material covered with a composite conductive layer. S3: The film material is etched to remove the metal mesh in the area not covered by the graphene layer, thereby simultaneously patterning the composite conductive layer into the desired antenna pattern. S4: Print conductive silver paste at the feed point position of the patterned antenna pattern to form a solder pad; S5: Perform RF performance testing on the antenna after the pads are formed; S6: If the performance test does not meet the requirements, the antenna pattern design is iteratively optimized based on the test results, and steps S2 to S5 are repeated. This process does not require changing the physical mold. S7: If the performance test is successful, apply an optical adhesive protective layer to the antenna pattern and expose the pads.

[0013] Preferably, the etching process is wet etching, in which the graphene layer acts as a partial mask during the etching process and is patterned together with the underlying metal mesh.

[0014] Preferably, the iterative optimization involves comparing test data with a simulation model, automatically adjusting the geometric parameters of the antenna pattern, and directly generating a new digital file for controlling spraying and printing.

[0015] Preferably, the spraying and printing process is pneumatic spraying, and the printing precision of the graphene pattern is not less than 20μm line width.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention achieves a balance between high performance and high transparency at the material level through a composite conductive layer structure of metal mesh and graphene. At the methodological level, it achieves a balance between high efficiency and high flexibility through a digital manufacturing process of spray printing and simultaneous etching. This solves the problem in existing technologies where transparent antennas are difficult to balance between flexibility, optical performance, conductivity, and design iteration efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure formed by the composite conductive layer of the present invention.

[0018] Figure 2 This is a schematic diagram of the dry film exposure structure of the present invention.

[0019] Figure 3 This is a schematic diagram of the antenna pattern with a metal mesh according to the present invention.

[0020] Figure 4 This is a schematic diagram of the structure of the pads of the present invention.

[0021] Figure 5 This is a schematic diagram of the transparent thin-film antenna with the composite conductive layer of the present invention.

[0022] In the diagram: 1-Transparent substrate; 2-Metal mesh; 3-Graphene layer; 4-Composite conductive layer; 5-Antenna pattern; 6-Pad; 7-Antenna; 8-Optical adhesive protective layer. Detailed Implementation

[0023] 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.

[0024] Please see Figure 1 The present invention provides a technical solution: the composite conductive layer transparent thin film antenna provided in the embodiment of the present invention includes a transparent substrate 1, a composite conductive layer 4 disposed on the transparent substrate 1, the composite conductive layer 4 being patterned by an etching process to form an antenna pattern 5, wherein the composite conductive layer 4 is composed of a metal mesh 2 and a graphene layer 3 covering the transparent substrate 1; the linewidth of the metal mesh 2 is ≤5μm, the thickness of the graphene layer 3 is ≤200nm, and the graphene layer 3 is tightly bonded to the surface of the metal mesh 2 by a spray printing process; the feed point of the antenna pattern 5 is provided with a pad 6 composed of conductive silver paste, the antenna pattern 5 is covered with an optical adhesive protective layer 8, and the optical adhesive protective layer 8 has a window for exposing the pad 6.

[0025] In this embodiment of the invention, the composite conductive layer 4 forms a complementary two-dimensional conductive network within the patterned antenna pattern 5 region, wherein the metal mesh 2 provides the main current path, and the graphene layer 3 fills the mesh gaps and forms a continuous two-dimensional conductive film.

[0026] The metal mesh 2 has a mesh shape of rhombus, square or hexagon, and a period of 50-500 μm. This design can effectively reduce optical diffraction and moiré patterns while ensuring conductivity. The graphene layer 3 is formed by printing and curing graphene ink with a concentration of less than 5%. The sheet resistance of the graphene layer 3 is 100-1000 Ω / sq. Its function is to enhance the flexibility and transparency of the antenna and to compensate for the insufficient conductivity of the metal mesh at low density.

[0027] The absolute value of the difference between the refractive index of the optical adhesive protective layer 8 and the refractive index of the transparent substrate 1 is ≤0.03, and the thickness of the optical adhesive protective layer 8 is 10-50μm, preferably 25μm. Through this optical matching design, interface reflection is reduced, and the transparency and display uniformity of the antenna are improved.

[0028] The transparent substrate 1 serves as the support carrier for the entire antenna. Its preferred material is COP film. The use of COP material is mainly due to its excellent optical properties, high light transmittance, low birefringence, low water absorption, and superior dimensional stability compared to PET. This ensures the reliability of the antenna in complex environments and the visual consistency of the display area. The thickness of the transparent substrate 1 is 25-100μm. Specifically, the metal mesh 2 is first prepared on the transparent substrate 1. Its line width is ≤5μm, and the preferred mesh shape is rhomboid with a period of 100μm. The metal mesh 2 constitutes the main conductive path of the antenna pattern 5, which is responsible for carrying and radiating high-frequency signal current.

[0029] This invention also provides a method for manufacturing a composite conductive layer transparent thin film antenna. This method, used to prepare the aforementioned composite conductive layer transparent thin film antenna, includes the following steps: S1: Provides a universal transparent substrate metal mesh 2, the transparent substrate 1 having a full-surface metal mesh 2, such as Figure 1 As shown; S2: Using a spray printing process, low-concentration graphene ink is printed onto the surface of the metal mesh 2 according to the preset antenna pattern 5 area. After curing, a graphene layer 3 is formed, thus obtaining a film material coated with a composite conductive layer 4, such as... Figure 2 As shown; S3: The film material is etched to remove the metal mesh 2 in areas not covered by the graphene layer 3, thereby simultaneously patterning the composite conductive layer 4 into the desired antenna pattern 5, such as... Figure 3 As shown; S4: Print conductive silver paste at the feed point location of the patterned antenna pattern 5 to form pad 6, such as... Figure 4 As shown; S5: Perform RF performance testing on the antenna after forming pad 6; S6: If the performance test does not meet the requirements, the antenna pattern 5 design will be iteratively optimized based on the test results, and steps S2 to S5 will be repeated. This process does not require changing the physical mold. S7: If the performance test meets the requirements, apply the optical adhesive protective layer 8 to the antenna pattern 5 and expose the solder pads 6, as follows. Figure 5 As shown.

[0030] In the manufacturing method, the etching process is wet etching. The graphene layer 3 acts as a partial mask during the etching process and is patterned together with the underlying metal mesh 2. Its function is to simplify the process steps, avoid the use of additional masks, and reduce costs.

[0031] Iterative optimization involves comparing test data with simulation models to automatically adjust the geometric parameters of antenna pattern 5 and directly generate new digital files for controlling spraying and printing. This method enables rapid design iteration without the need to remake physical molds, significantly improving R&D efficiency. The spraying and printing process is pneumatic spraying, and the printing precision of the graphene pattern is no less than 20μm in line width, ensuring the precise bonding of graphene layer 3 and metal mesh 2 to form a uniform conductive network.

[0032] This invention addresses the problems in mainstream transparent thin-film antenna technologies, such as the high brittleness and poor flexibility of indium tin oxide (ITO) and the moiré pattern of metal meshes, as well as the difficulty of iterative processing for complex patterning. By using composite conductive layers and digital manufacturing methods, it achieves an antenna structure with high transparency, low sheet resistance, good flexibility, and easy optimization design. The complementary conductive network of graphene layer 3 and metal mesh 2 is formed simultaneously through spraying and etching, ensuring a balance between electrical and optical performance. The iterative optimization steps are directly based on test feedback to adjust the pattern, giving the entire system high flexibility and repeatability.

[0033] 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 transparent thin-film antenna with a composite conductive layer, comprising a transparent substrate (1), characterized in that: A composite conductive layer (4) is disposed on the transparent substrate (1). The composite conductive layer (4) is patterned by etching process to form an antenna pattern (5). The composite conductive layer (4) is composed of a metal mesh (2) and a graphene layer (3) covering the transparent substrate (1). The metal mesh (2) has a line width of ≤5μm, the graphene layer (3) has a thickness of ≤200nm, and the graphene layer (3) is tightly bonded to the surface of the metal mesh (2) through a spray printing process. The antenna pattern (5) has a pad (6) made of conductive silver paste at its feed point; the antenna pattern (5) is covered with an optical adhesive protective layer (8), and the optical adhesive protective layer (8) has a window for exposing the pad (6).

2. The transparent thin-film antenna with a composite conductive layer according to claim 1, characterized in that: The metal mesh (2) and the graphene layer (3) form a complementary two-dimensional conductive network in the area of ​​the patterned antenna pattern (5). The metal mesh (2) provides the main current path, and the graphene layer (3) fills the mesh gaps and forms a continuous two-dimensional conductive film.

3. The transparent thin-film antenna with a composite conductive layer according to claim 1, characterized in that: The graphene layer (3) is formed by printing and curing graphene ink with a concentration of less than 5%, and the sheet resistance of the graphene layer (3) is in the range of 100-1000Ω / sq.

4. A transparent thin-film antenna with a composite conductive layer according to claim 1, characterized in that: The metal mesh (2) has a mesh shape of rhombus, square or hexagon, and the period of the metal mesh (2) is 50-500μm.

5. A transparent thin-film antenna with a composite conductive layer according to claim 1, characterized in that: The absolute value of the difference between the refractive index of the optical adhesive protective layer (8) and the refractive index of the transparent substrate (1) is ≤0.03, and the thickness of the optical adhesive protective layer (8) is 10-50μm.

6. A transparent thin-film antenna with a composite conductive layer according to claim 1, characterized in that: The transparent substrate (1) is a PET, COP or CPI film, and the thickness of the transparent substrate (1) is 25-100μm. The metal material of the metal mesh (2) is copper, silver or gold.

7. A method for manufacturing a transparent thin-film antenna with a composite conductive layer, characterized in that: This manufacturing method is used to prepare a composite conductive layer transparent thin film antenna as described in any one of claims 1-6, and includes the following steps: S1: Provides a metal mesh (2) for a universal transparent substrate, the transparent substrate (1) having a metal mesh (2) on the entire surface; S2: Using a spray printing process, low-concentration graphene ink is printed on the surface of a metal grid (2) according to the preset antenna pattern (5) area. After curing, a graphene layer (3) is formed, thereby obtaining a film material covered with a composite conductive layer (4). S3: The film material is etched to remove the metal mesh (2) in the area not covered by the graphene layer (3), thereby simultaneously patterning the composite conductive layer (4) into the desired antenna pattern (5). S4: Print conductive silver paste at the feed point position of the patterned antenna pattern (5) to form a pad (6). S5: Perform RF performance testing on the antenna after the pads (6) are formed; S6: If the performance test does not meet the requirements, the antenna pattern (5) design is iteratively optimized based on the test results, and steps S2 to S5 are repeated. This process does not require changing the physical mold. S7: If the performance test is successful, apply an optical adhesive protective layer (8) to the antenna pattern (5) and expose the pads (6).

8. A transparent thin-film antenna with a composite conductive layer according to claim 7, characterized in that: The etching process is a wet etching process, in which the graphene layer (3) acts as a partial mask during the etching process and is patterned together with the underlying metal mesh (2).

9. A transparent thin-film antenna with a composite conductive layer according to claim 7, characterized in that: The iterative optimization involves comparing the test data with the simulation model, automatically adjusting the geometric parameters of the antenna pattern (5), and directly generating a new digital file for controlling the spraying and printing.

10. A transparent thin-film antenna with a composite conductive layer according to claim 7, characterized in that: The spraying and printing process is a pneumatic spraying process, and the printing precision of the graphene pattern is not less than 20μm in line width.

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