Film layer system with selective electromagnetic shielding and high transmittance and method for producing same

Abstract

The application discloses a film layer system with selective electromagnetic shielding and high transmittance, which comprises a curved optical window, an electromagnetic shielding functional film, an electrode film and an infrared antireflection film; the film system material, structure and thickness of the electromagnetic shielding functional film and the electrode film are all the same; the optical window of the application adopts a curved surface, and a functional coating is prepared on the concave surface of the optical window and is enclosed in the system; while the same effect as the prior art is achieved, any external exposure of the functional coating is avoided, damage of wind sand, rain erosion and radiation from the external environment to the film layer is completely solved, and the ability of resisting high and low temperature, damp heat and other harsh environments is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of functional coating technology, and in particular to a light window film system with frequency-selective electromagnetic shielding and high transmittance functions, and its preparation method. Background Technology

[0002] In military fields such as aerospace and naval vessels, the electromagnetic interference in the space environment for various aircraft and weapons is becoming increasingly complex. The optical windows on these devices must possess high light transmittance and excellent imaging capabilities to ensure precise detection and observation. Simultaneously, they also need excellent electromagnetic shielding performance to effectively prevent electromagnetic interference from enemy radar, jamming systems, and other sources. Typically, composite functional coatings are applied to the windows of optoelectronic systems that transmit information to the outside world to address the issues of efficient transmission of target information and electromagnetic shielding against interference.

[0003] Patent CN 110519976 A, "A Sapphire Optical Window with Electromagnetic Shielding Function and its Preparation Method", describes a method for depositing an aluminum oxide film on a sapphire substrate by ion beam sputtering, encapsulating a metal mesh in the aluminum oxide film for protection, depositing electrodes, antireflective films, and hydrophobic films on the aluminum oxide film by evaporation, and then electroless plating a metal film. This method has a good protective effect, but the preparation process is relatively complex and costly.

[0004] Patent CN 109743872 A, "A Method for Preparing an Electromagnetic Shielding Film," prepares a grid structure layer by imprinting, filling the grooves with conductive silver paste to form a conductive grid. Patent CN 109652774 A, "A Method for Preparing an Electromagnetic Shielding Window with an Embedded Metal Grid," uses heat treatment to deposit a Y₂O₃ thin film onto the window, causing random mesh-like cracks in the film. A metal grid, thinner than the Y₂O₃ film, is then deposited on the cracked film surface, achieving an embedded metal grid. Both of these patents lack a protective film on the surface of the metal grid, leaving it exposed to the environment. This makes the grid prone to oxidation, detachment, and breakage, affecting its electromagnetic shielding performance and preventing long-term use in high / low temperature, humid / heat environments.

[0005] Patent CN 101121575 A, "A Method for Selective Metallization of Glass Surfaces Using Femtosecond Lasers," describes a method of selectively irradiating a silver nitrate film coated on a glass surface with a femtosecond laser to form silver particles, followed by electroless copper plating to metallize the irradiated area. Patent CN 103442544 A, "A Method for Preparing Embedded Metal Mesh," describes a method of forming mesh trenches through femtosecond laser scanning etching, followed by copper plating after heat treatment. Both methods produce metal meshes with advantages such as high bonding strength and good wear resistance; however, femtosecond laser processing has low efficiency and high cost, making it unsuitable for fabricating large-aperture optical windows.

[0006] Patent CN 104837325 A, "A Method for Preparing an Embedded Metal Mesh Electromagnetic Shielding Optical Window," involves spin-coating a titanium dioxide solution onto a substrate, allowing it to dry naturally to form a crack template. Conductive silver paste is then applied to the crack template to create an embedded, randomly cracked metal mesh. This method effectively avoids damage to the nano-silver paste that could compromise the electromagnetic shielding performance of the optical window. However, the titanium dioxide solution, being a cracking agent, experiences significant volume shrinkage during drying, causing crack warping, increasing crack width, and affecting the light transmittance of the optical window. Patent CN 104837326 A, "A Method for Fabricating an Electromagnetically Shielded Curved Optical Window with a Metal Mesh Structure," involves coating a substrate surface with crack-etching paint, drying it, depositing a conductive metal layer on the surface of a crack template, and removing the crack template to obtain a randomly cracked metal mesh. This method avoids the use of titanium dioxide as a cracking fluid, but the metal mesh is prepared on the convex surface of the optical window exposed to the external environment, which is susceptible to the effects of strong sunlight, rain erosion, sand erosion, and complex electromagnetic interference, which can cause chemical degradation, cracking or peeling of the metal mesh surface film and the mesh itself.

[0007] Patent CN 109407252 A, "A High Electromagnetic Shielding Optical Window and Its Preparation Method," protects the metal mesh by placing it in a sandwich structure between two optical glasses, thus preventing the metal mesh from being affected by the external environment and solving the problems of robustness and durability.

[0008] Issues such as abrasion resistance exist. However, the two pieces of optical glass affect transmittance, and the adhesive used to bond the optical glass will deteriorate after prolonged exposure to light.

[0009] Aging phenomena affect the lifespan of the light window.

[0010] Patent CN 110730608 A, “An Infrared Electromagnetic Shielding Window”, deposits an antireflective film and a metal mesh on the inner and outer sides of a gallium ester infrared glass, respectively. The addition of a slip-enhancing film and a protective film on the metal mesh improves the mechanical strength, wear resistance, and damp heat resistance of the mesh. However, the transmittance of the optical window is low, and the long-term stability of the protective film exposed to the outside world is problematic.

[0011] In addition, the fixtures used for coating optical windows are very expensive, with each fixture costing more than 100,000 yuan. They are generally not purchased in large quantities. Therefore, during the coating process of a batch of parts, there are often empty spaces on the tooling tray of the vacuum coating machine, which cannot be filled with parts, resulting in waste of coating materials and low processing efficiency. Summary of the Invention

[0012] The purpose of this invention is to overcome the shortcomings of the prior art and provide a film system with selective electromagnetic shielding and high transmittance, as well as a method for its preparation.

[0013] The objective of this invention is achieved through the following technical solution: a film system with selective electromagnetic shielding and high transmittance, comprising a curved optical window, an electromagnetic shielding functional film, an electrode film, and an infrared antireflection film; wherein the electromagnetic shielding functional film and the electrode film have the same film material, structure, and thickness;

[0014] Furthermore, the concave surface of the curved optical window has a grid groove; the electromagnetic shielding functional film is deposited in the grid groove; the electrode film is deposited on the electromagnetic shielding functional film; and the infrared anti-reflection film is deposited throughout the entire effective aperture of the curved optical window.

[0015] Furthermore, the period of the grid groove is 320±10μm to 500±10μm; the line width is 12±2μm.

[0016] Furthermore, the curved optical window is made of K9 glass substrate, ZnS substrate, Si substrate or Ge substrate;

[0017] Furthermore, the film materials of the electromagnetic shielding functional film and the electrode film include one or more of gold, silver, chromium, copper, aluminum, nickel, titanium, and silver alloys.

[0018] Furthermore, the film structure of the electromagnetic shielding functional film and the electrode film includes a connecting layer, a functional layer and a protective layer;

[0019] A further technical solution is that the infrared antireflection film comprises a single-layer or double-layer film prepared from one or two of magnesium fluoride, silicon dioxide, and OS-50.

[0020] Furthermore, the present invention provides a method for preparing an optical window film layer system with frequency-selective electromagnetic shielding and high-efficiency transmission functions, comprising the following steps: etching a grid trench on a photoresist surface of a curved optical window by laser direct writing and developing it by a developing process; depositing metal in the grid trench to obtain a metal grid;

[0021] Furthermore, the specific steps for depositing metal include: depositing an electromagnetic shielding functional film using physical vapor deposition; depositing an electrode film using physical vapor deposition after removing the photoresist; and depositing an infrared antireflection film on the effective aperture of the curved optical window using physical vapor deposition.

[0022] A further technical solution involves using physical vapor deposition (PVD) to deposit the electromagnetic shielding functional film and electrode film at an evaporation temperature of 60–120°C, an evaporation rate of 0.2–1.0 nm / s, and a vacuum degree of 3.0 × 10⁻⁶. -3 ~9.0×10 -4The vacuum oxygen flux is 8–12 sccm, the ion energy is 425–445 eV, and the electron beam current is 63–83 mA. The infrared antireflection film is deposited using physical vapor deposition at an evaporation temperature of 160–240 °C, an evaporation rate of 0.2–0.9 nm / s, and a vacuum level of 3.0 × 10⁻⁶. -3 ~9.0 × 10 -4 Pa, OS-50 vacuum oxygen flow rate is 8~15 sccm, silica vacuum oxygen flow rate is 0 sccm, OS-50 electron beam current is 280~340mA, silica electron beam current is 80~120mA.

[0023] The present invention has the following advantages:

[0024] 1. The optical window adopts a curved surface, and the functional coating is prepared on the concave surface of the optical window and sealed inside the system. While achieving the same effect as the existing technology, it avoids any external exposure of the functional coating, completely solves the damage to the film layer caused by wind, sand, rain erosion and radiation from the external environment, and greatly improves the ability to withstand harsh environments such as high and low temperatures and humid heat.

[0025] 2. The electromagnetic shielding functional film and the electrode film have the same film system materials, structure and thickness. This will not affect the functions of the electromagnetic shielding functional film and the electrode film respectively. The electromagnetic shielding film and the electrode film can be deposited separately in different areas of two batches of products. For example, batch one is optical parts without electromagnetic shielding functional film, and batch two is optical parts with electromagnetic shielding functional film already deposited and ready to be deposited with electrode film. The two batches of parts are placed in the vacuum coating machine at the same time, and the two films are deposited at the same time. This can improve the preparation efficiency and the utilization rate of film material, avoid waste, and eliminate the need to perform separate vapor deposition processes for the two batches of products.

[0026] 3. In this invention, a mesh groove is provided on the concave surface of the curved optical window of the optical system. After a film layer system is deposited on the mesh groove, a metal mesh with a certain pattern is formed. The period of the metal mesh of this invention is much larger than that of visible light or infrared light, and much smaller than that of electromagnetic wavelength. Because the period of the metal mesh is much smaller than that of electromagnetic wavelength, it has the function of electromagnetic shielding, that is, electromagnetic waves with longer wavelengths cannot pass through. And because the period of the metal mesh is much larger than that of visible light or infrared light, it has little effect on the transmittance of visible light or infrared light. This structural size selection enables the metal mesh to have the frequency filtering function of allowing high-frequency light waves to pass through and cutting off low-frequency microwaves.

[0027] 4. The film system prepared by this invention has high optical transmittance in the target band, high penetration effect in the target band and good shielding effect against interfering electromagnetic waves. The entire film system also has good environmental adaptability to high and low temperatures, humidity and heat.

[0028] 5. Preferably, the electromagnetic shielding functional film and the electrode film have the same film material, structure, and thickness. In principle, multiple layers can be set, and the more layers there are, the higher the transmittance. However, each layer absorbs, and the more layers there are, the greater the absorption, which may actually reduce the transmittance. With more layers, the adhesion and stress of each layer will be mismatched, and the firmness will also be worse. In addition, with more layers, each layer will have a certain error in the actual coating process. With more layers, the accumulated error will be more, and the film performance may also be worse. Therefore, the structure is set as a connecting layer, a functional layer, and a protective layer to meet the requirements of resistivity and film firmness.

[0029] 6. The functional layer located in the middle of the membrane structure is a metal or metal alloy, which plays the main functional role. The connecting layer in the membrane structure is used to strengthen the bond between the substrate material and the functional layer. The protective layer is used to isolate the functional layer from the air and protect the metal or metal alloy of the functional layer from scratches and chemical reactions with the atmosphere.

[0030] 7. The different metals or thicknesses located at different positions in the membrane structure are mainly to achieve their respective functions. For example, the connecting layer and the protective layer need to be able to achieve the functions of connection and protection, which is ultimately reflected in the firmness of the membrane layer and its ability to withstand the test of membrane firmness. Therefore, the membrane structure of the present invention shows good firmness and no delamination through adhesion test, and the temperature cycling test results are also good. After being kept at -45℃ and +55℃ for 2 hours and cycled 3 times, the surface of the product was inspected after the test, and the metal mesh did not break or fall off. The function of the functional layer is reflected in electromagnetic shielding. Different metals and thicknesses of the functional layer can achieve different sheet resistances, which ultimately affect the electromagnetic shielding efficiency.

[0031] 8. This invention preferably etches grating grooves on the concave surface of a curved optical window using laser direct writing, and then develops the grating grooves using a developing technique. Laser direct writing has weak etching intensity, is inexpensive, and does not produce difficult-to-remove debris. Especially since this invention involves laser etching on the concave surface of a curved optical window, if there is a lot of debris, it is even more difficult to clean. Although the intensity of laser etching is weak, by controlling the structure, period, and linewidth of the etched grating grooves, combined with the special film system of this invention, the resulting metal grating has frequency filtering functions that allow high-frequency light waves to pass through and block low-frequency microwaves. If other etching methods such as femtosecond lasers are used, the intensity is higher, but the cost is also higher, although the resulting...

[0032] There is a lot of debris, which makes cleaning inconvenient for curved optical windows. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the optical window film system structure of the present invention.

[0034] Figure 2This is a flowchart illustrating the fabrication process of the optical window film system of the present invention.

[0035] Figure 3 The transmittance of the K9-320 sample prepared in Example 4 in the range of 800-1000 nm.

[0036] Figure 4 The transmittance of the Zn-S-500 sample prepared in Example 5 in the range of 8-12 μm.

[0037] Figure 5 The transmittance of the K9-400 sample prepared in Example 3 in the range of 800-1000 nm.

[0038] Figure 6 The electromagnetic shielding efficiency of the K9-400 sample prepared for Example 3 in the range of 240MHz-2.5GHz.

[0039] Figure 7 The electromagnetic shielding efficiency of the K9-320 sample prepared for Example 4 in the range of 240MHz-2.5GHz.

[0040] Figure 8 The electromagnetic shielding efficiency of the ZnS-500 sample prepared in Example 5 in the range of 240MHz-2.5GHz.

[0041] Figure 9 The electromagnetic shielding efficiency of the Ge-400 sample prepared in Example 6 in the range of 240MHz-2.5GHz.

[0042] Figure 10 The electromagnetic shielding efficiency of the Si-400 sample prepared in Example 7 in the range of 240MHz-2.5GHz.

[0043] In the figure, 1-K9 glass substrate, 2-electromagnetic shielding functional film connecting layer, 3-electromagnetic shielding functional film metal grid layer, 4-electromagnetic shielding functional film protective layer, 5-electrode connecting layer, 6-electrode metal grid layer, 7-electrode protective layer, 8-infrared anti-reflection film. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0047] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0048] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0049] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium.

[0050] A connection can refer to the internal connection between two components. For those skilled in the art, this can be understood in the context of the specific situation.

[0051] The specific meanings of the terms used in this invention.

[0052] Example 1: A film system with selective electromagnetic shielding and high transmittance includes a curved optical window, an electromagnetic shielding functional film, an electrode film, and an infrared antireflection film. The electromagnetic shielding functional film and the electrode film have the same film system materials, structure, and thickness. The optical window is curved, and the functional coating is prepared on the concave surface of the optical window and sealed inside the system. While achieving the same effect as existing technologies, it avoids any external exposure of the functional coating, completely solving the damage to the film layer caused by wind, sand, rain erosion, and radiation from the external environment, and significantly improving the ability to withstand harsh environments such as high and low temperatures and humid heat. The film system of the electromagnetic shielding functional film and the electrode film... With identical materials, structure, and thickness, the electromagnetic shielding film and electrode film functions are not affected. Furthermore, the electromagnetic shielding film and electrode film can be deposited separately in different areas of two batches of products. For example, batch one consists of optical parts without electromagnetic shielding film, while batch two consists of optical parts with electromagnetic shielding film already deposited and ready for electrode film deposition. By placing these two batches of parts simultaneously in the vacuum coating machine, both films can be deposited at the same time. This improves preparation efficiency and film material utilization, avoids wasting film material and remaining space in the vacuum coating machine, and eliminates the need for separate vapor deposition processes for the two batches of products.

[0053] The curved optical window has a grid groove on its concave surface; the electromagnetic shielding film is deposited within the grid groove; the electrode film is deposited on the electromagnetic shielding film; and the infrared antireflective film is deposited throughout the entire effective aperture of the curved optical window. This invention provides a grid groove on the concave surface of the curved optical window of the optical system. After depositing the film system on the grid groove, a certain patterned metal grid is formed. Preferably, the electrode film is deposited at the required position of the electromagnetic shielding film, thus not affecting the function of the electrode film. The infrared antireflective film is deposited throughout the entire effective aperture of the curved optical window, which is beneficial for protection and overall antireflection. The film system prepared by this invention has high optical transmittance in the target band, high penetration effect in the target band, and good shielding effect against interfering electromagnetic waves. The entire film system also has good environmental adaptability to high and low temperatures and humidity.

[0054] The period of the mesh grooves is 320±10μm to 500±10μm; the linewidth is 12±2μm. In this embodiment, the period of the metal mesh is much larger than that of visible or infrared light, but much smaller than that of electromagnetic wavelengths. Because the period of the metal mesh is much smaller than that of electromagnetic wavelengths, it has an electromagnetic shielding function, meaning that longer wavelength electromagnetic waves cannot pass through. However, because the period of the metal mesh is much larger than that of visible or infrared light, it has little impact on the transmittance of visible or infrared light. This structural dimension selection enables the metal mesh to have frequency filtering functions, allowing high-frequency light waves to pass through while blocking low-frequency microwaves.

[0055] The curved optical window is made of K9 glass substrate, ZnS substrate, Si substrate or Ge substrate;

[0056] The membrane materials of the electromagnetic shielding functional membrane and electrode membrane include one or more of the following: gold, silver, chromium, copper, aluminum, nickel, titanium, and silver alloy.

[0057] The electromagnetic shielding functional film and the motor film have a film layer structure including a connecting layer, a functional layer, and a protective layer. The electromagnetic shielding functional film and the electrode film have the same film system materials, structure, and thickness. In principle, multiple layers can be set, and the more layers, the higher the transmittance. However, each layer absorbs, and the more layers there are, the greater the absorption, which may actually decrease the transmittance. With more layers, the adhesion and stress of each layer become mismatched, and the film's strength also deteriorates. Furthermore, with more layers, each layer will have a certain error during the actual coating process; the more layers there are, the more accumulated errors there are, and the film performance may also deteriorate. Therefore, the structure is set as a connecting layer, a functional layer, and a protective layer. The functional and protective layers meet the requirements for resistivity and membrane adhesion. The functional layer, located in the middle of the membrane structure, is made of metal or a metal alloy and plays a primary functional role. The connecting layer in the membrane structure strengthens the bond between the substrate material and the functional layer. The protective layer isolates the functional layer from the air, protecting the metal or metal alloy from scratches and chemical reactions with the atmosphere. The metals or thicknesses at different locations within the membrane structure are primarily for achieving their respective functions; for example, the connecting and protective layers need to provide both connection and protection, ultimately reflecting…

[0058] The film layer is robust and can withstand the film layer's strength requirements; while the functional layer's role is reflected in electromagnetic shielding, and different coatings are used for the functional layer.

[0059] The type of metal and its thickness can result in different surface resistivities, which ultimately affect the electromagnetic shielding efficiency.

[0060] The infrared antireflective film comprises a single-layer or double-layer film prepared from one or two of magnesium fluoride, silicon dioxide, and OS-50.

[0061] Example 2: A method for preparing an optical window film system with frequency-selective electromagnetic shielding and high-efficiency transmission. The method includes the following steps: etching a grid trench on a photoresist surface of a curved optical window by laser direct writing and developing it using a development process; depositing metal in the grid trench to obtain a metal grid.

[0062] The present invention preferably etches grating grooves on the concave surface of a curved optical window using laser direct writing, and then develops the grating grooves using a developing technique. Laser direct writing has weak etching intensity, is inexpensive, and does not produce difficult-to-remove debris. In particular, since the present invention performs laser etching on the concave surface of a curved optical window, it is even more difficult to clean if there is a lot of debris. Although the laser etching intensity is weak, by controlling the structure of the etched grating grooves, controlling the period and linewidth of the grating grooves, and then depositing the special metal film layer system of the present invention in the grating grooves, the resulting metal grating has the frequency filtering function of allowing high-frequency light waves to pass through and blocking low-frequency microwaves. If femtosecond laser etching is used, the intensity is high, but the price is also more expensive, and more debris is produced, which is inconvenient to clean for curved optical windows. While masking can be used to fabricate grating trenches, the slit diffraction effect makes it difficult to uniformly fabricate grating lines with linewidths on the micrometer scale on large-area substrates. Furthermore, since the metal grating is fabricated on the inner surface of a curved optical window, it's difficult to ensure that the mask and other etching and development methods are consistent with the surface shape of the optical window, resulting in localized inhomogeneities in the fabricated grating. Laser direct-write lithography focuses a laser beam onto the inner surface of the optical window, controls the direct-write path via computer, and after development, uniform grating lines are obtained without the need for a mask.

[0063] The specific steps for metal deposition include: depositing an electromagnetic shielding film using physical vapor deposition (PVD); depositing an electrode film using PVD after removing the photoresist; and depositing an infrared antireflection film on the effective aperture of the curved optical window using PVD. Deposition techniques include PVD and chemical vapor deposition (CVD). PVD uses a vacuum deposition machine, allowing for precise control of film thickness and resulting in high film strength; it is currently widely used. The method for removing the photoresist adhering to the optical window outside the grid is to immerse the curved optical window with the developed grid trenches in an acetone or N-methylpyrrolidone solution.

[0064] The evaporation temperature for electromagnetic shielding functional films and electrode films deposited using physical vapor deposition (PVD) is 60–120℃, the evaporation rate is 0.2–1.0 nm / s, the vacuum degree is 3.0 × 10⁻³–9.0 × 10⁻⁴ Pa, the vacuum oxygen flux is 8–12 sccm, the ion energy is 425–445 eV, and the electron beam current is 63–83 mA. The evaporation temperature for infrared antireflection films deposited using PVD is 160–240℃, the evaporation rate is 0.2–0.9 nm / s, the vacuum degree is 3.0 × 10⁻³–9.0 × 10⁻⁴ Pa, the OS-50 vacuum oxygen flux is 8–15 sccm, the silica vacuum oxygen flux is 0 sccm, the OS-50 electron beam current is 280–340 mA, and the silica electron beam current is 80–120 mA.

[0065] Example 3: K9-400 sample, prepared as follows: An electromagnetic shielding functional film was deposited on a clean K9 glass substrate with a grid groove pattern of 400±10μm period and 12±2μm linewidth using physical vapor deposition. The materials for the connecting layer, metal layer, and protective layer of the electromagnetic shielding functional film were chromium, copper, and chromium, respectively, with thicknesses of 10nm, 400nm, and 20nm. The deposition parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3nm / s, copper evaporation rate 0.8nm / s, and vacuum degree 3.0×10⁻³~9.0×

[0066] 10⁻⁴ Pa, electron beam current 72 mA, vacuum oxygen flow rate 8 sccm.

[0067] The sample with the electromagnetic shielding film deposited was cleaned in acetone or N-methylpyrrolidone solution to remove residual photoresist. Electrodes were then deposited on the edges of the component using physical vapor deposition. The electrode bonding layer, metal layer, and protective layer were made of chromium, copper, and chromium, respectively, with thicknesses of 10 nm, 400 nm, and 20 nm. The deposition parameters were: evaporation temperature 120 °C, chromium evaporation...

[0068] The electron beam evaporation rate was 0.3 nm / s, the copper evaporation rate was 0.8 nm / s, the vacuum level was 3.0 × 10⁻³ ~ 9.0 × 10⁻⁴ Pa, and the electron beam current was 72 mA.

[0069] Vacuum oxygen flow rate: 8 sccm.

[0070] Infrared antireflection films were deposited on an electromagnetic shielding layer using physical vapor deposition. The antireflection film materials were OS-50 and silicon dioxide, with thicknesses of 23 nm and 163 nm, respectively. The evaporation temperature was 200 °C, the evaporation rate of OS-50 was 0.3 nm / s, the evaporation rate of silicon dioxide was 0.8 nm / s, the vacuum degree was 3.0 × 10⁻³ to 9.0 × 10⁻⁴ Pa, the oxygen flux of OS-50 was 8 sccm, the oxygen flux of silicon dioxide was 0 sccm, the electron beam current of OS-50 was 300 mA, and the electron beam current of silicon dioxide was 100 mA.

[0071] Example 4: K9-320 sample, prepared as follows: An electromagnetic shielding functional film was deposited on a clean K9 glass substrate with a grid of 320±10μm period and 12±2μm linewidth using physical vapor deposition. The materials for the connecting layer, metal layer, and protective layer of the electromagnetic shielding functional film were chromium, copper, and chromium, respectively, with thicknesses of 10nm, 400nm, and 20nm. The deposition parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3nm / s, copper evaporation rate 0.8nm / s, and vacuum degree 3.0×10⁻³~9.0×

[0072] 10⁻⁴ Pa, electron beam current 72 mA, vacuum oxygen flow rate 8 sccm.

[0073] The sample with the electromagnetic shielding functional film deposited was cleaned in acetone or N-methylpyrrolidone solution to remove the photoresist. Electrodes were deposited on the edge of the part by physical vapor deposition. The electrode connection layer, metal layer and protective layer materials were chromium, copper and chromium, respectively, with thicknesses of 10 nm, 400 nm and 20 nm. The evaporation parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3 nm / s, copper evaporation rate 0.8 nm / s, vacuum degree 3.0×10-3~9.0×10-4 Pa, electron beam current 72 mA, and ion filling 8 sccm.

[0074] Infrared antireflection films were deposited on electromagnetic shielding films using physical vapor deposition. The first and second layers of the infrared antireflection films were made of OS-50 and silicon dioxide, respectively, with thicknesses of 23 nm and 163 nm. The evaporation temperature was 200 °C, the evaporation rate of OS-50 was 0.3 nm / s, the evaporation rate of silicon dioxide was 0.8 nm / s, the vacuum degree was 3.0 × 10⁻³ to 9.0 × 10⁻⁴ Pa, the oxygen flux of OS-50 was 8 sccm, the oxygen flux of silicon dioxide was 0 sccm, the electron beam current of OS-50 was 300 mA, and the electron beam current of silicon dioxide was 100 mA.

[0075] Example 5: ZnS-500 sample, prepared as follows: An electromagnetic shielding functional film was deposited on a clean ZnS substrate with a grid pattern of 500±10μm period and 12±2μm linewidth using physical vapor deposition. The materials for the connecting layer, metal layer, and protective layer of the electromagnetic shielding functional film were chromium, copper, and chromium, respectively, with thicknesses of 10nm, 500nm, and 20nm. The deposition parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3nm / s, copper evaporation rate 0.8nm / s, and vacuum degree 3.0 × 10⁻³~9.0 × 10⁻³.

[0076] 10⁻⁴ Pa, electron beam current 72 mA, vacuum oxygen flow rate 8 sccm.

[0077] The sample with the electromagnetic shielding functional film deposited was cleaned in acetone or N-methylpyrrolidone solution to remove residual photoresist. Electrode layers were deposited on the edge of the part using physical vapor deposition. The electrode connection layer, metal layer and protective layer materials were chromium, copper and chromium, respectively, with thicknesses of 10 nm, 500 nm and 20 nm. The evaporation parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3 nm / s, copper evaporation rate 0.8 nm / s, vacuum degree 3.0×10-3~9.0×10-4 Pa, electron beam current 72 mA, and vacuum oxygen flow rate 8 sccm.

[0078] Infrared antireflection films were deposited on electromagnetic shielding films using physical vapor deposition. The infrared antireflection film materials were OS-50 and silicon dioxide, with thicknesses of 23 nm and 163 nm, respectively. The evaporation temperature was 200 °C, the evaporation rate of OS-50 was 0.3 nm / s, the evaporation rate of silicon dioxide was 0.8 nm / s, the vacuum degree was 3.0 × 10⁻³ ~ 9.0 × 10⁻⁴ Pa, the oxygen flux of OS-50 was 8 sccm, the oxygen flux of silicon dioxide was 0 sccm, the electron beam current of OS-50 was 300 mA, and the electron beam current of silicon dioxide was 100 mA.

[0079] Example 6: Ge-400 sample, prepared as follows: An electromagnetic shielding functional film was deposited on a clean Ge substrate with a grid trench of 400±10 μm period and 12±2 μm linewidth using physical vapor deposition. The materials for the connecting layer, metal layer, and protective layer of the electromagnetic shielding functional film were chromium, copper, and chromium, respectively, with thicknesses of 10 nm, 400 nm, and 20 nm. The deposition parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3 nm / s, copper evaporation rate 0.8 nm / s, and vacuum degree 3.0 × 10⁻³ ~ 9.0 × 10⁻³.

[0080] 4 Pa, electron beam current 72 mA, vacuum oxygen flow rate 8 sccm.

[0081] The sample with the electromagnetic shielding functional film deposited was cleaned in acetone or N-methylpyrrolidone solution to remove residual photoresist. Electrodes were deposited on the edge of the part using physical vapor deposition. The electrode connection layer, metal layer and protective layer materials were chromium, copper and chromium, respectively, with thicknesses of 10 nm, 400 nm and 20 nm. The vapor deposition parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3 nm / s, copper evaporation rate 0.8 nm / s, vacuum degree 3.0 × 10-3~9.0 × 10-4 Pa, electron beam current 72 mA, and vacuum oxygen flow rate 8 sccm.

[0082] Infrared antireflection films were deposited on an electromagnetic shielding layer using physical vapor deposition. The antireflection film materials were OS-50 and silicon dioxide, with thicknesses of 23 nm and 163 nm, respectively. The evaporation temperature was 200 °C, the evaporation rate of OS-50 was 0.3 nm / s, the evaporation rate of silicon dioxide was 0.8 nm / s, the vacuum degree was 3.0 × 10⁻³ ~ 9.0 × 10⁻⁴ Pa, the oxygen flux of OS-50 was 8 sccm, the oxygen flux of silicon dioxide was 0 sccm, the electron beam current of OS-50 was 300 mA, and the electron beam current of silicon dioxide was 100 mA.

[0083] Example 7: Si-400 sample, the preparation steps of which are as follows: On a clean Si substrate with a grid trench with a period of 400±10μm and a linewidth of 12±2μm, an electromagnetic shielding functional film is deposited by physical vapor deposition. The materials of the electromagnetic shielding functional film connecting layer, metal layer and protective layer are chromium, copper and chromium, respectively, with thicknesses of 10nm, 400nm and 20nm, respectively. The evaporation parameters are: evaporation temperature 120℃, chromium evaporation rate 0.3nm / s, copper evaporation rate 0.8nm / s, vacuum degree 3.0 × 10-3~9.0 × 10-4Pa, electron beam current 72mA, and vacuum oxygen flow rate 8sccm.

[0084] The sample with the electromagnetic shielding functional film deposited was cleaned in acetone or N-methylpyrrolidone solution to remove residual photoresist. Electrodes were deposited on the edge of the part using physical vapor deposition. The electrode connection layer, metal layer and protective layer materials were chromium, copper and chromium, respectively, with thicknesses of 10 nm, 400 nm and 20 nm. The vapor deposition parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3 nm / s, copper evaporation rate 0.8 nm / s, vacuum degree 3.0 × 10-3~9.0 × 10-4 Pa, electron beam current 72 mA, and vacuum oxygen flow rate 8 sccm.

[0085] Infrared antireflection films were deposited on an electromagnetic shielding layer using physical vapor deposition. The antireflection film materials were OS-50 and silicon dioxide, with thicknesses of 23 nm and 163 nm, respectively. The evaporation temperature was 200 °C, the evaporation rate of OS-50 was 0.3 nm / s, the evaporation rate of silicon dioxide was 0.8 nm / s, the vacuum degree was 3.0 × 10⁻³ ~ 9.0 × 10⁻⁴ Pa, the oxygen flux of OS-50 was 8 sccm, the oxygen flux of silicon dioxide was 0 sccm, the electron beam current of OS-50 was 300 mA, and the electron beam current of silicon dioxide was 100 mA.

[0086] Example 8: Film Strength Test

[0087] The film adhesion test was performed according to GJB2485-1995. A 2cm wide adhesive tape with a peel strength of not less than 2.74N / cm was firmly adhered to the film surface. After being pulled up vertically and quickly, there was no film detachment.

[0088] The samples prepared in Examples 3-7 were designated as experimental groups 1-5;

[0089] Comparative Group 1: Prepared using the same method as in Example 3, except that the materials for the electrode's connecting layer, metal layer, and protective layer are chromium, copper, and chromium, respectively, with thicknesses of 0 nm, 400 nm, and 20 nm, respectively.

[0090] Comparative Group 2: Prepared using the same method as in Example 4, except that the electrode's connecting layer, metal layer, and protective layer are made of iron, copper, and iron, respectively, with thicknesses of 8 nm, 400 nm, and 15 nm.

[0091] Comparative Group 3: Prepared using the same method as in Example 5, except that the electrode's connecting layer, metal layer, and protective layer are made of gold, copper, and aluminum, respectively, with thicknesses of 8 nm, 400 nm, and 10 nm.

[0092] Comparative Group 4: Prepared using the same method as in Example 6, except that the electrode's connecting layer, metal layer, and protective layer are made of silver, copper, and nickel, respectively, with thicknesses of 9 nm, 400 nm, and 12 nm.

[0093] Comparative group 5: Prepared using the same method as in Example 7, except that the materials for the electrode's connecting layer, metal layer, and protective layer are aluminum, copper, and titanium, respectively, with thicknesses of 10 nm, 400 nm, and 18 nm.

[0094] The experimental results are shown in Table 1.

[0095] Example 9: Temperature Cycling Experiment

[0096] The temperature cycling test was performed according to GJB2485-1995, maintaining the temperature at -45℃ and +55℃ for 2 hours each, and repeating the cycle 3 times. After the test, the surface of the product was inspected, and the metal mesh did not break or fall off.

[0097] The samples prepared in Examples 3-7 were designated as experimental groups 1-5;

[0098] Comparative Group 1: Prepared using the same method as in Example 3, except that the materials for the electrode's connecting layer, metal layer, and protective layer are chromium, copper, and chromium, respectively, with thicknesses of 0 nm, 400 nm, and 20 nm, respectively.

[0099] Comparative Group 2: Prepared using the same method as in Example 4, except that the electrode's connecting layer, metal layer, and protective layer are made of iron, copper, and iron, respectively, with thicknesses of 8 nm, 400 nm, and 15 nm.

[0100] Comparative Group 3: Prepared using the same method as in Example 5, except that the electrode's connecting layer, metal layer, and protective layer are made of gold, copper, and aluminum, respectively, with thicknesses of 8 nm, 400 nm, and 10 nm.

[0101] Comparative Group 4: Prepared using the same method as in Example 6, except that the electrode's connecting layer, metal layer, and protective layer are made of silver, copper, and nickel, respectively, with thicknesses of 9 nm, 400 nm, and 12 nm.

[0102] Comparative group 5: Prepared using the same method as in Example 7, except that the materials for the electrode's connecting layer, metal layer, and protective layer are aluminum, copper, and titanium, respectively, with thicknesses of 10 nm, 400 nm, and 18 nm.

[0103] Table 1. Robustness and resistance to harsh environments such as high and low temperatures and humidity of membrane systems prepared with different membrane structures.

[0104] As shown in Table 1, the resistance to high and low temperatures and damp heat is mainly related to the membrane system. Different membrane systems and metal thicknesses in the technical solutions of this invention affect the resistance to high and low temperatures and damp heat. Since the membrane structures in experimental groups 1-5 include connecting layers and protective layers of suitable metal materials and thicknesses, their impact on the resistance to high and low temperatures and damp heat is small and almost negligible. However, once the metal materials and thicknesses of the connecting layers and protective layers are changed, the resistance to high and low temperatures and damp heat changes significantly. The robustness of the membrane system is similar.

[0105] Example 10: Transmittance Experiment

[0106] Experimental Group 1: The K9-400 sample prepared in Example 3 was used for transmittance experiments in the 800-1000 nm range. The results are as follows: Figure 5 As shown. From Figure 5 The results show that the transmittance is close to 90% in the 800-1000nm range.

[0107] Experimental Group 2: The transmittance of the K9-320 sample prepared in Example 4 was tested in the range of 800-1000 nm.

[0108] Structure as Figure 3 As shown. From Figure 3 The results show that the transmittance will be 82.16% in the 800-1000nm range.

[0109] Experimental Group 3: The ZnS-500 sample prepared in Example 5 was subjected to a transmittance experiment in the range of 8-12 μm, and the results are as follows. Figure 4 As shown. From Figure 4 The results show that the average transmittance is 83.42% and the peak transmittance is 88.88% in the 8-12µm range.

[0110] The comparison between experimental groups 1 and 2 shows that, with the same substrate material, different film structures, especially the different periods of the functional layer metal mesh, affect the transmittance. The comparison between experimental groups 1 and 3 shows that different substrate materials and different metal mesh structures affect the transmittance in different wavelength bands. Although the presence of the metal mesh provides electromagnetic shielding for the optical window, it also leads to a decrease in the optical transmittance of the window. Therefore, it is necessary to balance transmittance and electromagnetic shielding performance when designing the structural parameters of the metal mesh.

[0111] Example 11: Electromagnetic Shielding Experiment

[0112] Experimental Group 1: The K9-400 sample prepared in Example 3 was analyzed using a vector network analyzer N5225A at a detection frequency of 240MHz~2.5GHz. The electromagnetic shielding effect was as follows: Figure 6 As shown.

[0113] Experimental Group 2: Using the K9-320 sample prepared in Example 4, electromagnetic shielding effect was measured using a vector network analyzer N5225A at a frequency of 240MHz~2.5GHz. Figure 7 As shown.

[0114] Experimental Group 3: The ZnS-500 sample prepared in Example 5 was used. An N5225A vector network analyzer was used to detect the electromagnetic shielding effect at a frequency of 240MHz–2.5GHz. Figure 8 As shown.

[0115] Experimental Group 4: Using the Ge-400 sample prepared in Example 6, electromagnetic shielding effect was measured using a vector network analyzer N5225A at a frequency of 240MHz~2.5GHz. Figure 9 As shown.

[0116] Experimental Group 5: Using the Si-400 sample prepared in Example 7, the electromagnetic shielding effect was as follows: (The text abruptly ends here, so the translation stops as well.) Figure 10 As shown.

[0117] The comparison between experimental groups 1 and 2 shows that the same substrate material but different film structures affect electromagnetic shielding. This is because the metal is primarily used to achieve electromagnetic shielding, and different metals and thicknesses are mainly used to achieve different sheet resistances, which ultimately affect the electromagnetic shielding efficiency. Different film systems and metal thicknesses result in different sheet resistances, which in turn affect the electromagnetic shielding efficiency. Furthermore, the metal mesh period of experimental group 2 is 320 μm, and its shielding efficiency exceeds 35 dB in the 240 MHz to 2.5 GHz frequency band, slightly higher than the structure corresponding to experimental group 1. However, the average transmittance of experimental group 2 in the 800-1000 nm range is 82.16% lower than that of experimental group 1.

[0118] A comparison of Experiments 4 and 5 shows that they share the same metal mesh structure (period 400±10μm, linewidth 12±2μm) and metal film structure (electromagnetic shielding functional film connecting layer, metal layer, and protective layer materials are chromium, copper, and chromium, with thicknesses of 10nm, 400nm, and 20nm, respectively). The only difference is the substrate material, which is germanium (Ge) and silicon (Si), respectively. The electromagnetic shielding efficiency test report for the 240MHz~2.5GHz frequency band is provided by [Source Name]. Figure 9 and Figure 10 It can be seen that the electromagnetic shielding efficiency of Ge substrates in the 240MHz~2.5GHz frequency band exceeds 41dB, and that of Si substrates exceeds 31dB. Using this technical solution, metal mesh can be deposited on both Ge and Si substrates to achieve good electromagnetic shielding effects.

[0119] It is possible to prepare metal mesh grids with good electromagnetic shielding effect on Ge and Si substrates, which also corresponds to the prior art of being able to select different window materials to prepare metal mesh grids for different application conditions according to working requirements.

[0120] The comparison between experimental group 1 and experimental group 3 shows that the substrate materials, metal mesh structures, and film structures are all different. However, the presence of the metal mesh enables the optical windows to have strong electromagnetic shielding functions. This indicates that the technology can meet the requirements of different substrate materials, different transmission bands, and different electromagnetic shielding through the flexible design of the metal mesh, and has broad application prospects.

[0121] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a film system with selective electromagnetic shielding and high transmittance, characterized in that: include The following steps: 1) An electromagnetic shielding functional film was deposited on a clean Ge substrate with a grid of 400±10μm period and 12±2μm linewidth using physical vapor deposition. The materials for the connecting layer, metal layer, and protective layer of the electromagnetic shielding functional film were chromium, copper, and chromium, respectively, with thicknesses of 10nm, 400nm, and 20nm. The deposition parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3nm / s, copper evaporation rate 0.8nm / s, and vacuum degree 3.0×10⁻⁶. -3 ~9.0×10 -4 Pa, electron beam current 72mA, vacuum oxygen flow rate 8sccm; 2) The sample with the electromagnetic shielding functional film deposited was cleaned in acetone or N-methylpyrrolidone solution to remove residual photoresist. Electrodes were then deposited on the edge of the component using physical vapor deposition. The electrode bonding layer, metal layer, and protective layer materials were chromium, copper, and chromium, respectively, with thicknesses of 10 nm, 400 nm, and 20 nm. The deposition parameters were: evaporation temperature 120℃, chromium evaporation rate 0.3 nm / s, copper evaporation rate 0.8 nm / s, and vacuum degree 3.0 × 10⁻⁶. -3 ~9.0×10 -4 Pa, electron beam current 72mA, vacuum oxygen flow rate 8sccm; 3) An infrared antireflection film was deposited on the electromagnetic shielding layer using physical vapor deposition. The antireflection film materials were OS-50 and silicon dioxide, with thicknesses of 23 nm and 163 nm, respectively. The evaporation temperature was 200℃, the evaporation rate of OS-50 was 0.3 nm / s, and the evaporation rate of silicon dioxide was 0.8 nm / s. The vacuum degree was 3.0 × 10⁻⁶. -3 ~9.0×10 -4 Pa, OS-50 vacuum oxygen flow rate 8 sccm, silica vacuum oxygen flow rate 0 sccm, OS-50 electron beam current 300 mA, silica electron beam current 100 mA.

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