Embedded metal mesh multifunctional infrared carbon-based composite film and preparation method thereof

Abstract

The invention discloses an embedded metal mesh multifunctional infrared carbon-based composite film and a preparation method thereof, and belongs to the technical field of infrared antireflection films. The embedded metal mesh multifunctional infrared carbon-based composite film is composed of a base material, a metal mesh, a diamond-like layer, a graphite-like conductive layer and a conductive coating layer. The metal mesh is embedded in the base material, diamond-like layers and graphite-like conductive layers are sequentially and alternately arranged above the base material, the outermost layer is the diamond-like layer, all the diamond-like layers and the graphite-like conductive layers are coated with conductive coating layers, and the multiple graphite-like conductive layers are electrically connected into a parallel structure through the conductive coating layers; the composite film is suitable for selection of an infrared band, a metal mesh embedded structure and a carbon-based material, the mechanical strength of the composite film is improved, the composite film has a protection function, meanwhile, the composite film can be used as an electric heating film under the condition that no additional electrode is needed, and the composite film has a better shielding effect through a parallel structure and a microwave resonant cavity structure.

Description

Technical Field

[0001] The invention discloses an embedded metal grid multifunctional infrared carbon-based composite film and a preparation method thereof, belonging to the technical field of infrared anti-reflection films. Background Art

[0002] The radar stealth optical window structure is to make a periodic array or randomly arranged conductive metal grid on the surface of the optical window substrate, and then prepare an anti-reflection protective layer on the surface of the grid. The thickness of the grid and the anti-reflection protective layer of this structure is generally micron or submicron level, but the lattice constant and expansion coefficient of the metal grid are different from those of the substrate material, which is not conducive to the firmness, heat shock resistance, and laser damage resistance of the coated metal grid. The film layer is easily damaged under service conditions such as wind, sand, and rain. Therefore, the radar stealth window of this structure has a short lifespan.

[0003] In response to the above problems, the invention patent "A multi-band radar stealth composite structure light window and its preparation method" with application number 2023118601539 provides a solution. The multi-band radar stealth composite structure light window is arranged from bottom to top as a light window substrate, a conductive metal grid, a protective layer and an anti-reflection protective film layer. The conductive metal grid is periodically distributed on the upper surface of the light window substrate. The protective layer is made of the same material as the light window substrate. The anti-reflection film is arranged in multiple layers, and as it extends outward, the distance between adjacent anti-reflection films gradually decreases. Compared with traditional optical windows, the multi-band radar stealth composite structure light window has higher light transmittance and mechanical strength, so it can withstand harsh environments such as high and low temperatures, humidity, heat, salt spray, mold, and dust. Analyzing the above technical solution from the perspective of manufacturing process, it is equivalent to processing the conductive metal grid on the window surface and then wrapping it with an anti-reflection film to isolate the grid from the external environment.

[0004] In addition, the invention patent with application number 2023106557395, "A method for producing an embedded electromagnetic shielding metal grid", performs the following steps in sequence: making a reverse mask on the optical substrate, plasma beam etching metal grid grooves, metal film coating, bottom film coating, degumming and cleaning, and coating an optical anti-reflection film with environmental corrosion resistance; the production process is to groove the window surface, process the metal grid into the groove, and then seal the groove with an anti-reflection film, thereby isolating the grid from the external environment, so that the optical window can simultaneously achieve electromagnetic shielding, good optical transmittance, environmental corrosion resistance and other functions.

[0005] It can be seen that using a multi-layer composite film to isolate the metal grid from the external environment is an effective means to improve the optical performance and environmental tolerance of the metal grid-loaded window, and the existing technology has proved that embedding the metal grid in the substrate is a feasible process.

[0006] The invention patent with application number 2022107784103, "An infrared transparent conductive carbon-based film and its preparation method", provides a carbon-based film with the same protective function for the infrared band, and gives a production process, illustrating the feasibility of sandwiching a graphite-like conductive layer between two diamond-like layers. Summary of the invention

[0007] Based on the process that the metal grid can be isolated from the external environment and the graphite-like conductive layer can be sandwiched between two diamond-like layers, and based on the invention patent of our company's application number 2024116448543 "Optical anti-reflection protection electromagnetic shielding functional composite film in the visible light range", we have designed an embedded metal grid multifunctional infrared carbon-based composite film, which is suitable for the infrared band and can not only achieve the technical purpose of isolating the metal grid from the external environment, but also has a simple structure and rich functions.

[0008] The object of the present invention is achieved in that: The embedded metal grid multifunctional infrared carbon-based composite film consists of a substrate, a metal grid, a diamond-like layer, a graphite-like conductive layer and a conductive coating layer; the metal grid is embedded in the substrate, and above the substrate, diamond-like layers and graphite-like conductive layers are alternately arranged in sequence, and the outermost layer is a diamond-like layer, the diamond-like layers and the graphite-like conductive layers have the same projected area, and a conductive coating layer is coated on the outside of all diamond-like layers and graphite-like conductive layers, and a plurality of graphite-like conductive layers are electrically connected into a parallel structure by the conductive coating layer.

[0009] The above-mentioned embedded metal grid multifunctional infrared carbon-based composite film, the conductive coating layer is ITO or indium oxide.

[0010] The method for preparing an embedded metal grid multifunctional infrared carbon-based composite film comprises the following steps: Step a, embedding the metal grid into the substrate; Step b, sequentially preparing a diamond-like layer and a graphite-like conductive layer on a substrate to form a multilayer structure; Step c: coating the multilayer structure with a conductive coating layer on the periphery of the multilayer structure, wherein the graphite-like conductive layers are electrically connected to the conductive coating layer to form a parallel structure of multiple graphite-like conductive layers.

[0011] The beneficial effects of the embedded metal grid multifunctional infrared carbon-based composite film of the present invention are: First, the carbon-based materials of the diamond-like layer and the graphite-like conductive layer are selected so that the composite film of the present invention is suitable for the infrared band; Second, the metal grid is embedded in the substrate, so that the metal grid can also be isolated from the external environment, so as to achieve the technical purpose of higher mechanical strength and being able to withstand harsh environments; Third, the outermost layer is a diamond-like layer, and the conductive coating layer is selected from ITO or indium oxide, and both materials have high hardness, so that the composite film of the present invention can be used as a protective film to improve the environmental tolerance of optical devices; Fourth, the conductive coating layer connects the graphite-like conductive layer, so that the conductive coating layer itself can be used as an electrode, and the composite film of the present invention can be used as an electric heating film without the need for an external electrode; Fifth, the metal grid layer is processed by graphics, so that the composite film of the present invention also has electromagnetic shielding function; in addition, multiple graphite-like conductive layers are connected by the conductive coating layer to form a parallel structure, and the resistivity of the parallel structure is much lower than that of the single-layer structure, so the shielding effectiveness can be greatly improved; Sixth, a microwave resonant cavity is formed between the metal grid and the closest graphite-like layer. By adjusting the embedding depth of the metal grid, that is, changing the distance between the metal grid and the closest graphite-like layer, better shielding effect can be achieved at a specific distance and for a specific spectral band based on the principle of resonant absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic structural diagram of the embedded metal grid multifunctional infrared carbon-based composite film of the present invention.

[0013] In the figure: 1 substrate, 2 metal grid, 3 diamond-like layer, 4 graphite-like conductive layer, 5 conductive coating layer. DETAILED DESCRIPTION

[0014] The specific implementation modes of the present invention will be further described in detail below with reference to the accompanying drawings.

[0015] Method 1 The following is a specific implementation of the embedded metal grid multifunctional infrared carbon-based composite film of the present invention.

[0016] The structure diagram of the embedded metal grid multifunctional infrared carbon-based composite film in this specific implementation is as follows: Figure 1 As shown, it is composed of a substrate 1, a metal grid 2, a diamond-like layer 3, a graphite-like conductive layer 4 and a conductive coating layer 5; the metal grid 2 is embedded in the substrate 1, and above the substrate 1, the diamond-like layer 3 and the graphite-like conductive layer 4 are alternately arranged in sequence, and the outermost layer is the diamond-like layer 3, the diamond-like layer 3 and the graphite-like conductive layer 4 have the same projected area, and a conductive coating layer 5 is coated on the outside of all the diamond-like layers 3 and the graphite-like conductive layers 4, and a plurality of the graphite-like conductive layers 4 are electrically connected by the conductive coating layer 5 to form a parallel structure.

[0017] Method 2 The following is a specific implementation of the embedded metal grid multifunctional infrared carbon-based composite film of the present invention.

[0018] In the embedded metal grid multifunctional infrared carbon-based composite film in this specific implementation manner, the conductive coating layer 5 is ITO or indium oxide.

[0019] Method 3 The following is a specific implementation of the method for preparing the embedded metal grid multifunctional infrared carbon-based composite film of the present invention.

[0020] The method for preparing the embedded metal grid multifunctional infrared carbon-based composite film according to this specific embodiment comprises the following steps: Step a, embedding the metal grid 2 into the substrate 1; Step b, sequentially preparing a diamond-like layer 3 and a graphite-like conductive layer 4 on a substrate 1 to form a multilayer structure; Step c: coating the multilayer structure with a conductive coating layer 5 on the periphery of the multilayer structure, wherein the graphite-like conductive layers 4 are electrically connected to the conductive coating layer 5 to form a parallel structure of multiple graphite-like conductive layers 4.

Claims

1. Embedded metal grid multifunctional infrared carbon-based composite film, characterized in that: The invention comprises a substrate (1), a metal grid (2), a diamond-like layer (3), a graphite-like conductive layer (4) and a conductive coating layer (5); the metal grid (2) is embedded in the substrate (1); above the substrate (1), diamond-like layers (3) and graphite-like conductive layers (4) are alternately arranged in sequence, and the outermost layer is the diamond-like layer (3); the diamond-like layers (3) and the graphite-like conductive layers (4) have the same projected area; a conductive coating layer (5) is coated on the outside of all the diamond-like layers (3) and the graphite-like conductive layers (4); and a plurality of the graphite-like conductive layers (4) are electrically connected by the conductive coating layer (5) to form a parallel structure.

2. The embedded metal grid multifunctional infrared carbon-based composite film according to claim 1, characterized in that: The conductive coating layer (5) is ITO or indium oxide.

3. A method for preparing an embedded metal grid multifunctional infrared carbon-based composite film, characterized in that: The following steps are involved: Step a, embedding the metal grid (2) in the substrate (1); Step b, sequentially preparing a diamond-like layer (3) and a graphite-like conductive layer (4) on a substrate (1) to form a multilayer structure; Step c: coating the multilayer structure with a conductive coating layer (5) on the periphery of the multilayer structure, wherein the graphite-like conductive layers (4) are all electrically connected to the conductive coating layer (5) to form a parallel structure of multiple graphite-like conductive layers (4).

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