Electromagnetic shielding multifunctional composite film of embedded metal mesh and preparation method of electromagnetic shielding multifunctional composite film

Abstract

The invention discloses an electromagnetic shielding multifunctional composite film of an embedded metal mesh and a preparation method of the electromagnetic shielding multifunctional composite film, and belongs to the technical field of optical antireflection films. The high-refractive-index conductive film is formed by alternating a base material, a metal mesh, a high-refractive-index conductive film layer and a low-refractive-index film layer, the metal mesh is embedded in the base material, the high-refractive-index conductive film layer and the low-refractive-index film layer are sequentially and alternately arranged above the base material, the outermost layer is the high-refractive-index conductive film layer, the low-refractive-index film layer is subjected to graphical processing, and the high-refractive-index conductive film layer and the low-refractive-index film layer are sequentially and alternately arranged on the base material. The projection area of the low-refractive-index film layer is smaller than that of the high-refractive-index conductive film layers, and the multiple high-refractive-index conductive film layers are communicated outside the low-refractive-index film layer; the metal mesh embedded structure and the material selection of the high-refractive-index conductive film layer and the low-refractive-index film layer increase the mechanical strength of the composite film, have a protection function, can be used as an electric heating film without additional electrodes, and enable the composite film to have a better shielding effect through the parallel structure and the microwave resonant cavity structure.

Description

Technical Field

[0001] The invention discloses an electromagnetic shielding multifunctional composite film of an embedded metal grid and a preparation method thereof, and belongs to the technical field of optical anti-reflection films. Background Art

[0002] The radar stealth optical window structure is to make a periodic array or randomly arranged 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 metal grid, a protective layer and an anti-reflection protective film layer. The 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 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. Summary of the invention

[0006] Based on the invention patent "Optical anti-reflection protection electromagnetic shielding functional composite film in the visible light range" with application number 2024116448543 of our company, we have designed an electromagnetic shielding multifunctional composite film with embedded metal grid. It 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.

[0007] The object of the present invention is achieved in that: The electromagnetic shielding multifunctional composite film with embedded metal grid is composed of a substrate, a metal grid, a high refractive index conductive film layer and a low refractive index film layer alternatingly. The metal grid is embedded in the substrate. Above the substrate, high refractive index conductive film layers and low refractive index film layers are alternately arranged in sequence, and the outermost layer is a high refractive index conductive film layer. The low refractive index film layer is patterned, and the projected area of ​​the low refractive index film layer is smaller than that of the high refractive index conductive film layer. Multiple high refractive index conductive film layers are connected outside the low refractive index film layer.

[0008] In the above-mentioned electromagnetic shielding multifunctional composite film with embedded metal grid, the high refractive index conductive film layer is ITO or indium oxide; and the low refractive index film layer is magnesium fluoride.

[0009] The method for preparing an electromagnetic shielding multifunctional composite film with an embedded metal grid comprises the following steps: Step a, embedding the metal grid into the substrate; Step b, sequentially preparing a low refractive index film layer and a high refractive index conductive film layer on a substrate to form a multilayer structure; Step c: On the periphery of the multilayer structure, the multilayer structure is coated with the same material as the high refractive index conductive film layer to form a high refractive index conductive film layer connected to the outside of the low refractive index film layer.

[0010] The beneficial effects of the electromagnetic shielding multifunctional composite film of the embedded metal grid of the present invention are: First, 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; Second, the high refractive index conductive film layer is made of ITO, and the low refractive index film layer is made of magnesium fluoride. 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; Third, the high refractive index conductive film layer has conductive properties, and multiple high refractive index conductive film layers are connected outside the low refractive index film layer, so that the high refractive index conductive film layer itself can be used as an electrode. Without the need for an external electrode, the composite film can be used as an electric heating film; Fourth, the low refractive index film layer is subjected to a graphic treatment, so that the composite film of the present invention also has an electromagnetic shielding function; in addition, multiple high refractive index conductive film layers are connected outside the low refractive index film layer, so that the high refractive index conductive film layers form a parallel structure, and the resistivity of this parallel structure is much lower than that of a single layer of high refractive index conductive film layer, so that the shielding effectiveness can be greatly improved; Fifth, a microwave resonant cavity is formed between the metal grid and the closest high-refractive-index conductive film. By adjusting the embedding depth of the metal grid, that is, changing the distance between the metal grid and the closest high-refractive-index conductive film 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

[0011] Figure 1 It is a structural schematic diagram of the electromagnetic shielding multifunctional composite film of the embedded metal grid of the present invention.

[0012] In the figure: 1 substrate, 2 metal grid, 3 high refractive index conductive film layer, 4 low refractive index film layer. DETAILED DESCRIPTION

[0013] The specific implementation modes of the present invention will be further described in detail below with reference to the accompanying drawings.

[0014] Method 1

[0015] The following is a specific implementation of the electromagnetic shielding multifunctional composite film of the embedded metal grid of the present invention.

[0016] The electromagnetic shielding multifunctional composite film with embedded metal grid in this specific implementation manner has a structural schematic diagram as shown in FIG. Figure 1 As shown, it is composed of a substrate 1, a metal grid 2, a high refractive index conductive film layer 3 and a low refractive index film layer 4 alternatingly, the metal grid 2 is embedded in the substrate 1, and above the substrate 1, the high refractive index conductive film layer 3 and the low refractive index film layer 4 are alternately arranged in sequence, and the outermost layer is the high refractive index conductive film layer 3, the low refractive index film layer 4 is patterned, and the projected area of ​​the low refractive index film layer 4 is smaller than the high refractive index conductive film layer 3, and the multiple high refractive index conductive film layers 3 are connected outside the low refractive index film layer 4.

[0017] The high refractive index conductive film layer 3 is ITO or indium oxide; the low refractive index film layer 4 is magnesium fluoride.

[0018] Method 2

[0019] The following is a specific implementation of the method for preparing the electromagnetic shielding multifunctional composite film of the embedded metal grid of the present invention.

[0020] The method for preparing the electromagnetic shielding multifunctional composite film of the embedded metal grid in this specific embodiment comprises the following steps: Step a, embedding the metal grid 2 into the substrate 1; Step b, sequentially preparing a low refractive index film layer 4 and a high refractive index conductive film layer 3 on a substrate 1 to form a multilayer structure; Step c: On the periphery of the multilayer structure, the multilayer structure is coated with the same material as the high refractive index conductive film layer 3 to form a high refractive index conductive film layer 3 connected to the outside of the low refractive index film layer 4.

Claims

1. An electromagnetic shielding multifunctional composite film with embedded metal grid, characterized in that: The invention is composed of a substrate (1), a metal grid (2), a high refractive index conductive film layer (3) and a low refractive index film layer (4) which are alternately arranged. The metal grid (2) is embedded in the substrate (1). Above the substrate (1), high refractive index conductive film layers (3) and low refractive index film layers (4) are alternately arranged in sequence, and the outermost layer is the high refractive index conductive film layer (3). The low refractive index film layer (4) is patterned, and the projected area of ​​the low refractive index film layer (4) is smaller than that of the high refractive index conductive film layer (3). A plurality of high refractive index conductive film layers (3) are connected outside the low refractive index film layer (4).

2. The electromagnetic shielding multifunctional composite film of embedded metal grid according to claim 1, characterized in that: The high refractive index conductive film layer (3) is ITO or indium oxide; and the low refractive index film layer (4) is magnesium fluoride.

3. A method for preparing an electromagnetic shielding multifunctional composite film with an embedded metal grid, characterized in that: The following steps are involved: Step a, embedding the metal grid (2) in the substrate (1); Step b: sequentially preparing a low refractive index film layer (4) and a high refractive index conductive film layer (3) on a substrate (1) to form a multilayer structure; Step c: On the periphery of the multilayer structure, the multilayer structure is coated with the same material as the high refractive index conductive film layer (3), so that the high refractive index conductive film layer (3) is connected to the outside of the low refractive index film layer (4).

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