High-hardness antireflection film window processing method applied to atmosphere infrared window wave band

Abstract

The invention belongs to the technical field of photoelectric detection and sensing and infrared imaging, and relates to a high-hardness antireflection film window processing method applied to an atmospheric infrared window wave band. Comprising the following steps: selecting a zinc selenide infrared crystal as a window material, selecting zinc selenide, ytterbium fluoride, zirconium oxide and diamond-like carbon as optical thin film materials, designing a film system structure, and respectively completing plating of a first surface film system structure and a second surface film system structure and finished product detection by adopting a vacuum coating mode. Compared with the prior art, the surface hardness, corrosion resistance, adhesion resistance and infrared band transmittance of the infrared crystal window are improved, the infrared crystal window has excellent infrared spectrum transmission performance and environmental adaptability, the service life of the infrared crystal window is prolonged, long-term stable operation of an infrared detection system is guaranteed, and the service life of the infrared detection system is prolonged. And a solid foundation is provided for iteration upgrading of infrared detection and infrared imaging equipment.

Description

Technical Field

[0001] The present invention belongs to the fields of photoelectric detection and sensing technology and infrared imaging technology, and in particular relates to a method for processing a high-hardness antireflection film window applied to an atmospheric infrared window band. Background Art

[0002] Infrared radiation is a significant part of the electromagnetic spectrum, with wavelengths ranging from 0.76 μm to 1 mm, between visible light and microwaves. Based on wavelength, infrared radiation can be categorized as near infrared (NIR), shortwave infrared (SWIN), medium wave infrared (MWIR), long wave infrared (LWIR), very long wave infrared (VLWIR), and far infrared (FIR).

[0003] Although the infrared spectrum is rich in information, only a portion of the infrared light can pass through the atmosphere and be used by humans due to absorption, scattering, and reflection by atmospheric gases (such as H₂O, CO, CO₂, O₃, and CH₄) and small suspended particles. This portion of infrared light is known as the atmospheric infrared window. The atmospheric infrared window is primarily divided into three bands: the shortwave infrared window, the mediumwave infrared window, and the longwave infrared window. The 1μm to 3μm band is known as the shortwave infrared window and is used for geological surveys, marine environmental monitoring, and monitoring plants and crops with high water content. The 3μm to 5μm band is known as the mediumwave infrared window and is used to detect radiation from high-temperature objects such as forest fires, aircraft exhaust blasts, and explosive gases. The 8μm to 14μm band is known as the longwave infrared window. Because the peak wavelength of thermal radiation from the human body at a temperature of 300K (27°C) is around 10μm, this band is used for nighttime imaging, among other applications.

[0004] In recent years, with the rapid advancement of optical materials, photoelectric detection devices, and computer software, optoelectronic systems have increasingly become lightweight, multifunctional, miniaturized, and integrated. Such optoelectronic systems inevitably incorporate numerous optical paths and detection devices to achieve the integrated application of diverse functions. The infrared crystal windows of such optoelectronic systems must achieve high transmittance across two or more atmospheric infrared window bands. Furthermore, to meet the requirements for a long lifespan in harsh atmospheric environments, the atmospherically exposed surfaces of the infrared crystal windows must be hardened to prevent scratches from dust, erosion from smog, and chemical reactions from acid rain.

[0005] Despite improvements in material selection and basic processing techniques, existing infrared crystal windows still struggle to fully meet the demands of practical applications. For example, uncoated zinc selenide (ZnSe) infrared crystal windows have a transmittance of just over 68% in the 1.0μm to 16μm infrared band. Furthermore, their surface hardness is extremely low, making them susceptible to scratching and their chemical stability is extremely poor, making them susceptible to deterioration and loss of infrared spectroscopy performance. This significantly limits the stable operation of infrared detection systems in harsh climates. Therefore, technical personnel in this field urgently need to develop new high-hardness anti-reflection film window processing methods that can be applied to the atmospheric infrared window band to improve the surface hardness, corrosion resistance, anti-adhesion and infrared band transmittance of the infrared crystal window, thereby extending the service life of the window and ensuring the long-term stable operation of the infrared detection system. Summary of the Invention

[0006] The purpose of the present invention is to provide a new method for processing high-hardness anti-reflection film windows that can be applied to the atmospheric infrared window band, so as to improve the surface hardness, corrosion resistance, anti-adhesion and infrared band transmittance of the infrared crystal window, thereby extending the service life of the window and ensuring the long-term stable operation of the infrared detection system.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides a method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band, comprising the following steps: S1. Select zinc selenide infrared crystal as the window material; S2. Select zinc selenide, ytterbium fluoride, zirconium oxide and diamond-like carbon as optical thin film materials; S3. Design the membrane system structure, where the first membrane system structure is as follows: Sub / 0.1L0.54H0.256L0.437H0.367L0.404H0.393L0.399H0.419L0.353H0.48L0.276H0.554L0.16H1.024L0.04M / Air; The second mask system structure is as follows: Sub / 0.1L0.54H0.253L0.448H0.35L0.44H1.347L0.0.464H0.355L0.432H0.4L0.366H0.47L0.262H0.68L0.145D / Air; In the above film system structure, Sub is the zinc selenide infrared crystal substrate, Air is air, H is the zinc selenide film material, L is the ytterbium fluoride film material, M is the zirconium oxide film material, and D is the diamond-like carbon film. The number before the film layer is the optical thickness coefficient of the corresponding film layer at one-quarter central wavelength. S4, using a vacuum coating method to complete the coating of the first mask system structure and the second mask system structure respectively; S5. Finished product inspection.

[0008] Preferably, in step S1, the material spectrum transparency range of the zinc selenide infrared crystal is 0.65 μm to 16 μm, the material is highly transparent in the atmospheric infrared window band, and the surface roughness of the window after polishing is better than 0.01 μm.

[0009] Preferably, the material spectrum transparency range of the zinc selenide film material is 0.65μm~16μm, and its refractive index n=2.44 at the spectral wavelength λ=1.32μm, and it has high refractive index and high transparency in the atmospheric infrared window band; the material spectrum transparency range of the ytterbium fluoride film material is 0.35μm~14μm, and its refractive index n=1.5 at the spectral wavelength λ=1.32μm, and it has low refractive index and high transparency in the atmospheric infrared window band; the material spectrum transparency of the zirconium oxide film material is 0.65μm~16μm, and its refractive index n=2.44 at the spectral wavelength λ=1.32μm, and it has low refractive index and high transparency in the atmospheric infrared window band; The region is 0.3μm to 12μm, and its refractive index n=2.02 at the spectral wavelength λ=1.32μm. It has high refractive index and high transparency in the atmospheric infrared window band and high chemical stability in the atmospheric environment. The transparent region of the diamond-like film material is from near infrared to far infrared, especially in the atmospheric infrared window band, it is highly transparent and has no absorption. Its refractive index n=2.4 at the spectral wavelength λ=2.0μm. The material has friction resistance, high hardness, high thermal conductivity, high insulation, and excellent chemical stability.

[0010] Preferably, the first mask is installed in the corresponding optoelectronic device, and the optoelectronic device is filled with nitrogen or dry gas, which is beneficial to extending the service life of the first surface; the second mask is structurally installed in the atmospheric environment. Preferably, in the film system structure, the actual physical thickness of each film layer is calculated as follows:

[0011] Where λ is the spectral wavelength of 2.0 μm, α is the optical thickness coefficient of the corresponding film layer at one quarter of the central wavelength, and n is the refractive index of the film material at the spectral wavelength.

[0012] Preferably, in step S4, the zinc selenide film material, the ytterbium fluoride film material, and the zirconium oxide film material are plated using the APS ion source assisted method of the SYSpro1100 vacuum coating machine; and the diamond-like carbon film is plated using the chemical vapor deposition method of the FHL700 vacuum coating machine.

[0013] Preferably, in step S4, during vacuum coating, the first surface film system structure is processed first, then the second surface bottom film system structure is processed, and finally the second surface top film system is processed.

[0014] Preferably, in step S4: When processing the first film structure, the infrared crystal substrate is placed in the vacuum chamber of the SYSpro1100 vacuum coating machine. When the vacuum degree is higher than 6×10 -2 Pa, bake the infrared crystal substrate at 120℃, keep the temperature constant for 30min~40min, and continue to evacuate; when the vacuum degree is higher than 2×10 -3 When Pa, the APS ion source was turned on for cleaning for 10 minutes; then ytterbium fluoride film material, zinc selenide film material and zirconium oxide film material were alternately plated in the order of film layers. After the plating was completed, the film was cooled to room temperature and the film was taken out; When processing the second bottom film structure, the infrared crystal substrate coated with the first film structure is placed in the vacuum chamber of the SYSpro1100 vacuum coating machine. When the vacuum degree is higher than 6×10 -2 Pa, the infrared crystal substrate coated with the first film structure was baked at 120 ° C, kept at constant temperature for 30 min to 40 min, and continued to vacuum; when the vacuum degree was higher than 2×10 -3 At Pa, the APS ion source was turned on for cleaning for 10 minutes; then ytterbium fluoride film and zinc selenide film were alternately plated in the order of film layers. After the plating was completed, the film was cooled to room temperature and the film was taken out; When processing the second top film structure, the infrared crystal substrate coated with the second bottom film structure is turned to the vacuum chamber of the FHL700 vacuum coating machine chemical vapor deposition equipment. When the vacuum degree is higher than 3×10 -2 Pa, the infrared crystal substrate coated with the second bottom film structure was baked at 80℃, kept at constant temperature for 80min~90min, and continued to vacuum; when the vacuum degree was higher than 2×10 -3 Pa, turn on the RF power supply for cleaning for 10 minutes, then chemically vapor deposit the diamond-like carbon film to the set thickness, cool it to room temperature, and take out the part.

[0015] Preferably, step S5 includes: measuring the spectral curve of the film system of the finished product using a spectrometer. When the measurement results meet the spectral characteristics of the average transmittance of the short-wave infrared from 1.1μm to 2.8μm being higher than 90%, the average transmittance of the medium-wave infrared from 3.2μm to 4.8μm being higher than 90%, and the average transmittance of the long-wave infrared from 8.0μm to 12μm being higher than 88%, it is judged as a qualified product. Otherwise, it is an unqualified product.

[0016] Preferably, the spectrometer is a UV-VIS-NIR fully automatic spectrometer or a Fourier transform infrared spectrometer.

[0017] The present invention also includes other devices or steps that enable it to proceed normally, which are all conventional technical means in the field. In addition, the devices or steps not limited in the present invention all adopt conventional means in the existing technology.

[0018] The working principle of the present invention is that on one side of the zinc selenide infrared crystal window, high-refractive-index zinc selenide (ZnSe) film, zirconium oxide (ZrO2) film, and low-refractive-index ytterbium fluoride (YbF3) film are selected as film system materials, and a high-transmittance infrared anti-reflection film is coated, and a high-refractive-index zirconium oxide (ZrO2) film with high chemical stability in the atmospheric environment is coated on the outermost layer; on the other side, high-refractive-index zinc selenide (ZnSe) film and low-refractive-index ytterbium fluoride (YbF3) film are selected as the bottom film system materials, and a high-hardness infrared anti-reflection film is coated. In order to ensure the use requirements in harsh atmospheric environments, a diamond-like carbon (DLC) high-hardness protective layer is coated on the top layer of the film system.

[0019] The beneficial effects of the present invention are as follows: the zinc selenide infrared crystal window coated on both sides of the present invention has an average transmittance of more than 90% in the atmospheric infrared window band of 1.1μm to 2.8μm short-wave infrared, an average transmittance of more than 90% in the 3.2μm to 4.8μm medium-wave infrared, and an average transmittance of more than 88% in the 8.0μm to 12μm long-wave infrared, thereby improving the surface hardness, corrosion resistance, anti-adhesion and infrared band transmittance of the infrared crystal window, having excellent infrared spectral transmittance and environmental adaptability, extending the service life of the infrared crystal window, and being conducive to ensuring the long-term stable operation of the infrared detection system, and providing a solid foundation for the iterative upgrade of infrared detection and infrared imaging equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings and examples.

[0021] Figure 1 1 is an overall process flow chart of the present invention in the embodiment.

[0022] Figure 2 Schematic diagram of the ion membrane cleaning process in the embodiment.

[0023] Figure 3 Schematic diagram of the ion source assisted plating process in the embodiment.

[0024] Figure 4 Schematic diagram of the process of non-ion source assisted plating in the embodiment.

[0025] Figure 5 Schematic diagram of the chemical vapor deposition process in the embodiment.

[0026] Figure 6 Schematic diagram of the membrane system structure of the present invention in the embodiment.

[0027] Figure 7 3 is a material spectrum characteristic diagram of the zinc selenide infrared crystal of the present invention in the embodiment.

[0028] Figure 8 This is a spectrum characteristic diagram of the zinc selenide infrared crystal of the present invention after the first surface is coated.

[0029] Figure 9 This is a spectrum characteristic diagram of the zinc selenide infrared crystal of the present invention after the second surface coating is completed in the embodiment. DETAILED DESCRIPTION

[0030] The present invention is described below in conjunction with the accompanying drawings and specific embodiments of the present invention. The description herein is only used to explain the present invention and is not intended to limit the present invention. Based on the embodiments of the present invention, any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art without creative work based on all other embodiments obtained in the present invention should be included in the scope of protection of the present invention.

[0031] Example like Figure 1 As shown, the method for processing a high-hardness antireflection film window applied to the atmospheric infrared window band provided by the present invention comprises the following steps: S1. Zinc selenide infrared crystal is selected as the window material. The optical crystal has a diameter of 100mm and a thickness of 10mm. The technical specifications for the coating on both sides are as follows: the average transmittance of the short-wave infrared from 1.1μm to 2.8μm is greater than 90%, the average transmittance of the medium-wave infrared from 3.2μm to 4.8μm is greater than 90%, and the average transmittance of the long-wave infrared from 8.0μm to 12μm is greater than 88%. The rest is in accordance with JB / T8226.3-1999. The spectral transparency of the zinc selenide infrared crystal is from 0.65μm to 16μm, with high transparency in the atmospheric infrared window band. The surface roughness of the window after polishing is better than 0.01μm. S2. Select zinc selenide, ytterbium fluoride, zirconium oxide and diamond-like carbon as optical thin film materials; the material spectral transparency range of the zinc selenide film material is 0.65μm~16μm, and its refractive index n=2.44 at the spectral wavelength λ=1.32μm, and it has high refractive index and high transparency in the atmospheric infrared window band; the material spectral transparency range of the ytterbium fluoride film material is 0.35μm~14μm, and its refractive index n=1.5 at the spectral wavelength λ=1.32μm, and it has low refractive index and high transparency in the atmospheric infrared window band; The material spectral transparency range of the zirconium oxide film material is 0.3μm to 12μm, and its refractive index n=2.02 at the spectral wavelength λ=1.32μm. It has high refractive index and high transparency in the atmospheric infrared window band and high chemical stability in the atmospheric environment; the material transparency range of the diamond-like film is from near infrared to far infrared, especially highly transparent and non-absorbent in the atmospheric infrared window band, and its refractive index n=2.4 at the spectral wavelength λ=2.0μm. The material has friction resistance, high hardness, high thermal conductivity, high insulation, and excellent chemical stability.

[0032] S3. Design the membrane system structure, where the first membrane system structure is as follows: Sub / 0.1L0.54H0.256L0.437H0.367L0.404H0.393L0.399H0.419L0.353H0.48L0.276H0.554L0.16H1.024L0.04M / Air; The second mask system structure is as follows: Sub / 0.1L0.54H0.253L0.448H0.35L0.44H1.347L0.0.464H0.355L0.432H0.4L0.366H0.47L0.262H0.68L0.145D / Air; In the above film system structure, Sub is the zinc selenide infrared crystal substrate, Air is air, H is the zinc selenide film material, L is the ytterbium fluoride film material, M is the zirconium oxide film material, and D is the diamond-like carbon film. The number before the film layer is the optical thickness coefficient of the corresponding film layer at one-quarter central wavelength. In the film structure, the actual physical thickness of each film layer is calculated as follows:

[0033] Where λ is the spectral wavelength of 2.0 μm, α is the optical thickness coefficient of the corresponding film layer at one quarter of the central wavelength, and n is the refractive index of the film material at the spectral wavelength.

[0034] The material thicknesses of the first mask system and the second mask system are shown in Table 1 and Table 2, respectively.

[0035] Table 1 Physical thickness of the first surface

[0036] Table 2 Physical thickness of the second side

[0037] In this embodiment, the first face film is installed in the corresponding optoelectronic device, and the interior of the optoelectronic device is filled with nitrogen or dry gas, which is beneficial to extending the service life of the first face; the second face film structure is installed in the atmospheric environment. S4, using a vacuum coating method to complete the coating of the first mask system structure and the second mask system structure respectively; First, the surface roughness of the optical component substrate was inspected to ensure it was free of deteriorated layers, cracks, or scratches, meeting the 3×0.1 requirement in GB / T 1185-2006. Next, the component was cleaned with a 1:1 alcohol-ether mixture using a degreased gauze cloth. The surface was free of dust, water stains, oil stains, or other contaminants.

[0038] like Figures 2 to 5As shown, zinc selenide, ytterbium fluoride, and zirconium oxide films were deposited using the SYSpro1100 vacuum coater's APS ion source-assisted coating method. Optical thin films produced using this ion source-assisted method are dense and flat, with low absorption and scattering coefficients. The films exhibit strong mechanical strength, high hardness, excellent durability, and good environmental adaptability. Diamond-like carbon films were deposited using chemical vapor deposition (CVD) using the FHL700 vacuum coater. CVD utilizes radio frequency glow discharge to form a plasma, ionizing the working gases argon (Ar) and methane (CH4) within a vacuum chamber. The positive ions, under the influence of an electric field, are deposited on the negative electrode, resulting in a diamond-like carbon (DLC) film on the substrate. The resulting films are strong, low-stress, high-hardness, and abrasion-resistant.

[0039] like Figure 6 As shown, during vacuum coating, according to the physical thickness of the film layer in Table 1 and Table 2 and the process parameters in Table 3 and Table 4, the first surface film system structure is processed first, then the second surface bottom film system structure is processed, and finally the second surface top film system is processed.

[0040] The environmental parameters of the vacuum coating room are: temperature: 22℃~26℃, humidity: 40%~60%, cleanliness: Class 10,000. When processing the first film structure, the infrared crystal substrate is placed in the vacuum chamber of the SYSpro1100 vacuum coating machine. When the vacuum degree is higher than 6×10 -2 Pa, the infrared crystal substrate was baked at 120 ° C, kept at constant temperature for 30min~40min, and then vacuumed. Baking and keeping constant temperature for the infrared crystal substrate can improve the surface activity of the substrate and improve the film firmness. When the vacuum degree is higher than 2×10 -3 When the temperature reaches 1000 Pa, the APS ion source is turned on for cleaning for 10 minutes. Cleaning the substrate can remove dust, water vapor, oil and other pollutants on the substrate surface to reduce the occurrence of film defects. Then, ytterbium fluoride film material, zinc selenide film material and zirconium oxide film material are alternately plated in the order of film layers. After the plating is completed, the film is cooled to room temperature and the film is taken out. When processing the second bottom film structure, the infrared crystal substrate coated with the first film structure is placed in the vacuum chamber of the SYSpro1100 vacuum coating machine. When the vacuum degree is higher than 6×10 -2 Pa, the infrared crystal substrate coated with the first film structure is baked at 120 ° C, kept at a constant temperature for 30 min to 40 min, and then vacuumed. Baking and keeping the infrared crystal substrate constant can improve the surface activity of the substrate and improve the film firmness. When the vacuum degree is higher than 2×10 -3 When the temperature is 0.5°C, the APS ion source is turned on for cleaning for 10 minutes. Cleaning the substrate can remove dust, water vapor, oil and other pollutants on the substrate surface to reduce the occurrence of film defects. Then, ytterbium fluoride film and zinc selenide film are alternately plated in the order of film layers. After plating, the film is cooled to room temperature and the film is taken out. When processing the second top film structure, according to the process parameters in Table 4, the infrared crystal substrate coated with the second bottom film structure is turned into the vacuum chamber of the FHL700 vacuum coating machine chemical vapor deposition equipment. When the vacuum degree is higher than 3×10 -2 Pa, the infrared crystal substrate coated with the second bottom film structure was baked at 80 ° C, kept at a constant temperature for 80 min to 90 min, and then vacuumed. Baking and keeping the infrared crystal substrate constant can improve the surface activity of the substrate and improve the firmness of the film. When the vacuum degree is higher than 2×10 -3 Pa, turn on the RF power supply for cleaning for 10 minutes. Cleaning the substrate can remove dust, water vapor and other pollutants on the substrate surface and reduce the occurrence of film defects; then chemical vapor deposition of diamond-like carbon film, vapor deposition time is 8 minutes (vapor deposition time controls DLC thickness), cool to room temperature, and take out the part.

[0041] Table 3 APS ion source assisted coating film process parameters

[0042] Table 4 Chemical vapor deposition process parameters

[0043] S5. Finished product inspection: Use a Fourier transform infrared spectrometer to measure the spectral characteristics of the infrared optical crystal.

[0044] like Figure 7 As shown in the figure (the horizontal axis represents wavelength, and the vertical axis represents transmittance), the transmission spectrum curve of the light blank of the zinc selenide infrared crystal in the 1.0μm~14μm band has an average transmittance T≥68%.

[0045] like Figure 8 As shown in the figure (the horizontal axis represents wavelength and the vertical axis represents transmittance), after the first side of the zinc selenide infrared crystal is coated, the average transmittance in the short-wave infrared band of 1.1μm to 2.8μm is higher than 80.5%, the average transmittance in the medium-wave infrared band of 3.2μm to 4.8μm is higher than 80.5%, and the average transmittance in the long-wave infrared band of 8.0μm to 12μm is higher than 80%.

[0046] like Figure 9 As shown in the figure (the horizontal axis represents wavelength and the vertical axis represents transmittance), after the second side of the zinc selenide infrared crystal is coated, the average transmittance in the 1.1μm~2.8μm short-wave infrared band is higher than 90%, the average transmittance in the 3.2μm~4.8μm medium-wave infrared band is higher than 90%, and the average transmittance in the 8.0μm~12μm long-wave infrared band is higher than 88%.

[0047] According to the measurement results, the spectral characteristics of the product meet the requirements that the average transmittance of short-wave infrared from 1.1μm to 2.8μm is higher than 90%, the average transmittance of medium-wave infrared from 3.2μm to 4.8μm is higher than 90%, and the average transmittance of long-wave infrared from 8.0μm to 12μm is higher than 88%. The film properties also meet the JB / T8226.8-1999 standard. Therefore, it is judged to be a qualified product. Otherwise, it is unqualified.

[0048] In this embodiment, the cleaning reagents, film materials, equipment, optical software, and spectrometer used refer to the following standards: Alcohol-ether mixture: GB / T 678 chemical reagent ethanol (anhydrous ethanol); GB / T 12591 Chemical reagent ether; Thin film materials: ZnSe: purity above 99.99%, YbF3: purity above 99.99%; Coating machine: SYRUSpro1100 coating machine, FHL700 vacuum coating machine; Spectrometer: Shimadzu FTIR-8400S Fourier transform infrared spectrometer; Optical thin film analysis software: TFC optical thin film software; Film test according to: JB / T8226.3-1999; Optical parts surface defects: GB / T 1185-2006; The working principle of the present invention is that on one side of the zinc selenide infrared crystal window, high-refractive-index zinc selenide (ZnSe) film, zirconium oxide (ZrO2) film, and low-refractive-index ytterbium fluoride (YbF3) film are selected as film system materials, and a high-transmittance infrared anti-reflection film is coated, and a high-refractive-index zirconium oxide (ZrO2) film with high chemical stability in the atmospheric environment is coated on the outermost layer; on the other side, high-refractive-index zinc selenide (ZnSe) film and low-refractive-index ytterbium fluoride (YbF3) film are selected as the bottom film system materials, and a high-hardness infrared anti-reflection film is coated. In order to ensure the use requirements in harsh atmospheric environments, a diamond-like carbon (DLC) high-hardness protective layer is coated on the top layer of the film system.

[0049] While the embodiments of the present invention have been described above, the above description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band, characterized in that: The steps include: S1. Select zinc selenide infrared crystal as the window material; S2. Select zinc selenide, ytterbium fluoride, zirconium oxide and diamond-like carbon as optical thin film materials; S3. Design the membrane structure, including: The structure of the first mask system is as follows: Sub / 0.1L0.54H0.256L0.437H0.367L0.404H0.393L0.399H0.419L0.353H0.48L0.276H0.554L0.16H1.024L0.04M / Air; The second mask system structure is as follows: Sub / 0.1L0.54H0.253L0.448H0.35L0.44H1.347L0.0.464H0.355L0.432H0.4L0.366H0.47L0.262H0.68L0.145D / Air; In the above film system structure, Sub is the zinc selenide infrared crystal substrate, Air is air, H is the zinc selenide film material, L is the ytterbium fluoride film material, M is the zirconium oxide film material, and D is the diamond-like carbon film. The number before the film layer is the optical thickness coefficient of the corresponding film layer at one-quarter central wavelength. S4, using a vacuum coating method to complete the coating of the first mask system structure and the second mask system structure respectively; S5. Finished product inspection.

2. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 1, characterized in that: In step S1, the material spectrum transparency range of the zinc selenide infrared crystal is 0.65 μm to 16 μm.

3. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 1, characterized in that: The material spectral transparency range of the zinc selenide film is 0.65μm~16μm, and its refractive index n=2.44 at the spectral wavelength λ=1.32μm; the material spectral transparency range of the ytterbium fluoride film is 0.35μm~14μm, and its refractive index n=1.5 at the spectral wavelength λ=1.32μm; the material spectral transparency range of the zirconium oxide film is 0.3μm~12μm, and its refractive index n=2.02 at the spectral wavelength λ=1.32μm; the material transparency region of the diamond-like carbon film is from near infrared to far infrared, especially in the atmospheric infrared window band, it is highly transparent and has no absorption, and its refractive index n=2.4 at the spectral wavelength λ=2.0μm.

4. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 1, characterized in that: The first mask is installed in the corresponding optoelectronic device, and the interior of the optoelectronic device is filled with nitrogen or dry gas; the second mask is structurally installed in the atmospheric environment.

5. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 1, characterized in that: In the film structure, the actual physical thickness of each film layer is calculated as follows: Where λ is the spectral wavelength of 2.0 μm, α is the optical thickness coefficient of the corresponding film layer at one quarter of the central wavelength, and n is the refractive index of the film material at the spectral wavelength.

6. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 1, characterized in that: In step S4, zinc selenide film, ytterbium fluoride film, and zirconium oxide film are deposited using the SYSpro1100 vacuum coating machine with APS ion source assistance; and diamond-like carbon film is deposited using the FHL700 vacuum coating machine with chemical vapor deposition.

7. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 6, characterized in that: In step S4, during vacuum coating, the first surface film system structure is processed first, then the second surface bottom film system structure is processed, and finally the second surface top film system is processed.

8. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 7, characterized in that: In step S4: When processing the first film structure, the infrared crystal substrate is placed in the vacuum chamber of the SYSpro1100 vacuum coating machine. When the vacuum degree is higher than 6×10 -2 Pa, bake the infrared crystal substrate at 120℃, keep the temperature constant for 30min~40min, and continue to evacuate; when the vacuum degree is higher than 2×10 -3 When Pa, the APS ion source was turned on for cleaning for 10 minutes; then ytterbium fluoride film material, zinc selenide film material and zirconium oxide film material were alternately plated in the order of film layers. After the plating was completed, the film was cooled to room temperature and the film was taken out; When processing the second bottom film structure, the infrared crystal substrate coated with the first film structure is placed in the vacuum chamber of the SYSpro1100 vacuum coating machine. When the vacuum degree is higher than 6×10 -2 Pa, the infrared crystal substrate coated with the first film structure was baked at 120 ° C, kept at constant temperature for 30 min to 40 min, and continued to vacuum; when the vacuum degree was higher than 2×10 -3 At Pa, the APS ion source was turned on for cleaning for 10 minutes; then ytterbium fluoride film and zinc selenide film were alternately plated in the order of film layers. After the plating was completed, the film was cooled to room temperature and the film was taken out; When processing the second top film structure, the infrared crystal substrate coated with the second bottom film structure is turned to the vacuum chamber of the FHL700 vacuum coating machine chemical vapor deposition equipment. When the vacuum degree is higher than 3×10 -2 Pa, the infrared crystal substrate coated with the second bottom film structure was baked at 80℃, kept at constant temperature for 80min~90min, and continued to vacuum; when the vacuum degree was higher than 2×10 -3 Pa, turn on the RF power supply for cleaning for 10 minutes, then chemically vapor deposit the diamond-like carbon film to the set thickness, cool it to room temperature, and take out the part.

9. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 8, characterized in that: Step S5 includes: using a spectrometer to measure the spectral curve of the finished film system. When the measurement results meet the spectral characteristics of an average short-wave infrared transmittance of 1.1μm to 2.8μm higher than 90%, an average medium-wave infrared transmittance of 3.2μm to 4.8μm higher than 90%, and an average long-wave infrared transmittance of 8.0μm to 12μm higher than 88%, the product is judged to be qualified. Otherwise, it is an unqualified product.

10. The method for processing a high-hardness antireflection film window for use in the atmospheric infrared window band according to claim 9, characterized in that: The spectrometer is a UV-VIS-NIR fully automatic spectrometer or a Fourier transform infrared spectrometer.

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