A high durability antireflection film for infrared 3-5 mu m band chalcogenide glass and a preparation method thereof

Abstract

The application belongs to the technical field of infrared coating and discloses a high-durability antireflection film for chalcogenide glass in the 3-5 mu m infrared band, which comprises a film system structure symmetrically arranged on both sides of a chalcogenide glass substrate, wherein the film system structure comprises, in sequence from the inside to the outside of the chalcogenide glass substrate, a first germanium layer, a first zinc sulfide layer, a second germanium layer, a second zinc sulfide layer, a third germanium layer, a third zinc sulfide layer, a ytterbium fluoride layer, a fourth zinc sulfide layer and a lanthanum fluoride layer. The film system structure is arranged on the chalcogenide glass substrate to improve the wear resistance, corrosion resistance and transmittance of the lens.

Description

Technical Field

[0001] This invention belongs to the field of infrared coating technology, specifically relating to the preparation of antireflective films, and more particularly to a high-durability antireflective film for chalcogenide glass in the infrared 3-5μm band and its preparation method. Background Technology

[0002] Chalcogenide glasses are glasses primarily composed of Group VIA elements (S, Se, and Te) from the periodic table, with the addition of certain amounts of other metallic elements. They have a small temperature coefficient of refractive index (dn / dT); for example, germanium (Ge) materials have an average dn / dT of 400 × 10⁻⁶ in the 3–12 μm wavelength range. -6 K -1 The typical dn / dT of a Se-based chalcogenide glass is 50 × 10⁻⁶. -6 K -l ~90×10 -6 K -1 It possesses excellent heat dissipation properties; its refractive index is low (2.0–3.0), and its refractive index dispersion characteristics are comparable to zinc selenide in the long-wavelength range, exhibiting excellent anti-dispersion performance. Furthermore, chalcogenide glasses have advantages such as a wide transmission spectral range, a small refractive index temperature coefficient, and moldability, making them increasingly common in infrared optical systems.

[0003] When using chalcogenide glass as a substrate to process high-precision optical lenses, high requirements are placed on the lens's corrosion resistance and transmittance. However, traditional infrared antireflective coatings prepared on chalcogenide glass substrates cannot meet these requirements in terms of corrosion resistance and transmittance. In existing technologies, to improve the wear resistance of antireflective coatings, a DLC film is usually prepared on the outermost layer of the antireflective coating to resist harsh external environments. However, the DLC film significantly reduces the light transmittance of the lens, affecting its transmittance. Summary of the Invention

[0004] In view of the defects and deficiencies of the existing technology, the present invention provides, in a first aspect, a high-durability antireflection film for chalcogenide glass in the infrared 3-5μm band; in a second aspect, the present invention provides a method for preparing the above-mentioned high-durability antireflection film for chalcogenide glass in the infrared 3-5μm band.

[0005] To achieve the above objectives, the present invention provides the following technical solutions.

[0006] In a first aspect, the present invention provides a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band, comprising a film structure symmetrically disposed on both sides of a chalcogenide glass substrate, wherein the film structure comprises, in sequence from the inner side to the outer side of the chalcogenide glass substrate, a first germanium layer, a first zinc sulfide layer, a second germanium layer, a second zinc sulfide layer, a third germanium layer, a third zinc sulfide layer, a ytterbium fluoride layer, a fourth zinc sulfide layer, and a lanthanum fluoride layer.

[0007] Preferably, the thickness of the first germanium layer is 77.08±3 nm; the thickness of the first zinc sulfide layer is 90.33±3 nm; the thickness of the second germanium layer is 267.52±3 nm; the thickness of the second zinc sulfide layer is 118±3 nm; the thickness of the third germanium layer is 74.02±3 nm; the thickness of the third zinc sulfide layer is 90.68±3 nm; the thickness of the ytterbium fluoride layer is 383.17±3 nm; the thickness of the fourth zinc sulfide layer is 55.63±3 nm; and the thickness of the lanthanum fluoride layer is 79.26±3 nm.

[0008] Secondly, the present invention provides a method for preparing the above-mentioned high-durability antireflection film in the infrared 3-5μm band of chalcogenide glass, comprising the following steps:

[0009] Step 1: Sequentially deposit a first germanium layer, a first zinc sulfide layer, a second germanium layer, a second zinc sulfide layer, a third germanium layer, a third zinc sulfide layer, a ytterbium fluoride layer, a fourth zinc sulfide layer, and a lanthanum fluoride layer on one side of the substrate.

[0010] Step 2: Repeat step 1 to deposit a film structure on the other side of the substrate.

[0011] Preferably, in step 1, the substrate is a chalcogenide glass substrate.

[0012] Before step 1, there is also a substrate cleaning stage, in which the substrate surface is cleaned using a Hall ion source.

[0013] Further optimization is achieved by using the Hall ion source parameters as follows when cleaning the substrate: neutralization current 0.5~0.7A, neutralization gas flow rate 8sccm, anode voltage 200~240V, anode current 1.8~2.2A, and argon gas flow rate 100%.

[0014] Preferably, the germanium layer is prepared by electron beam heating evaporation, and the zinc sulfide layer, ytterbium fluoride layer, and lanthanum fluoride layer are prepared by resistance heating evaporation.

[0015] Further optimization involves using an ion-assisted deposition process to prepare germanium, zinc sulfide, ytterbium fluoride, and lanthanum fluoride layers.

[0016] Preferably, when depositing the germanium layer, the evaporation rate of germanium is 4 Å / s.

[0017] Further optimization is achieved by using the following ion source parameters when depositing the germanium layer: neutralization current 0.4~0.6A, neutralization gas flow rate 8sccm, anode voltage 70~90V, anode current 0.6~0.8A, and argon gas flow rate 100%.

[0018] Preferably, when depositing the zinc sulfide layer, the evaporation rate of the zinc sulfide is 6 Å / s.

[0019] Further optimization is achieved by using the following ion source parameters when depositing the zinc sulfide layer: neutralization current 0.4~0.6A, neutralization gas flow rate 8sccm, anode voltage 80~120V, anode current 0.8~1.2A, and argon gas flow rate 100%.

[0020] Preferably, when depositing the ytterbium fluoride layer, the evaporation rate of the ytterbium fluoride is 5 Å / s.

[0021] Preferably, when depositing the lanthanum fluoride layer, the evaporation rate of the lanthanum fluoride is 6 Å / s.

[0022] Further optimization yielded the following ion source parameters for depositing the ytterbium fluoride and lanthanum fluoride layers: neutralization current 0.5~0.7A, neutralization gas flow rate 6~10sccm, anode voltage 110~150V, anode current 1.1~1.5A, argon flow rate 30%, and oxygen flow rate 70%.

[0023] Preferably, in step 1, the coating vacuum degree is 4.5 × 10⁻⁶. -3 ~5.5×10 -3 Pa.

[0024] Preferably, in step 1, the coating temperature is 125~135℃.

[0025] Preferably, after step 1, there is also a heat preservation and cooling stage.

[0026] Further optimization involves setting the insulation temperature to 125-135℃ and the insulation duration to 20-40 minutes.

[0027] Further optimization involves removing the product once the temperature drops by 50-70°C.

[0028] Compared with the prior art, the present invention has the following significant advantages:

[0029] (1) By setting a film structure on a chalcogenide glass substrate, the reflection peaks in a specific wavelength range can be effectively eliminated by using the interference effect and the principle of destructive interference. Furthermore, the combination of germanium layer, zinc sulfide layer, ytterbium fluoride layer and lanthanum fluoride layer can improve the wear resistance, corrosion resistance and transmittance of the lens.

[0030] (2) The preparation method provided by the present invention is simple and easy to obtain a membrane structure with high transmittance, which is conducive to promotion and marketization. Attached Figure Description

[0031] Figure 1 The transmittance curve of the high-durability antireflection film in the infrared 3-5μm band of chalcogenide glass prepared in Example 1 of this invention is shown.

[0032] Figure 2The transmittance curve of the high-durability antireflection film in the infrared 3-5μm band of chalcogenide glass prepared in Example 2 of this invention is shown.

[0033] Figure 3 The transmittance curve of the high-durability antireflection film in the infrared 3-5μm band of chalcogenide glass prepared in Example 3 of this invention is shown.

[0034] Figure 4 The image shows the transmittance curve of the high-durability antireflective coating in the infrared 3-5μm band of chalcogenide glass prepared in Comparative Example 2 of this invention.

[0035] Figure 5 The image shows the transmittance curve of the high-durability antireflective coating in the infrared 3-5μm band of chalcogenide glass prepared in Comparative Example 3 of this invention. Detailed Implementation

[0036] The present invention provides the following specific technical solutions.

[0037] In a first aspect, the present invention provides a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band, comprising a film structure symmetrically disposed on both sides of a chalcogenide glass substrate, wherein the film structure comprises, in sequence from the inner side to the outer side of the chalcogenide glass substrate, a first germanium layer, a first zinc sulfide layer, a second germanium layer, a second zinc sulfide layer, a third germanium layer, a third zinc sulfide layer, a ytterbium fluoride layer, a fourth zinc sulfide layer, and a lanthanum fluoride layer.

[0038] The inventors discovered that the alternating stacking of germanium, zinc sulfide, ytterbium fluoride, and lanthanum fluoride layers utilizes interference effects and the principle of destructive interference to eliminate reflection peaks within a specific wavelength range, thereby reducing reflectivity in the 3-5μm infrared light band.

[0039] Preferably, the thickness of the first germanium layer is 77.08±3 nm; the thickness of the first zinc sulfide layer is 90.33±3 nm; the thickness of the second germanium layer is 267.52±3 nm; the thickness of the second zinc sulfide layer is 118±3 nm; the thickness of the third germanium layer is 74.02±3 nm; the thickness of the third zinc sulfide layer is 90.68±3 nm; the thickness of the ytterbium fluoride layer is 383.17±3 nm; the thickness of the fourth zinc sulfide layer is 55.63±3 nm; and the thickness of the lanthanum fluoride layer is 79.26±3 nm.

[0040] In practice, the thickness of each film layer can be adjusted according to actual needs and based on optical theory. The inventors discovered that the film structure exhibits the highest transmittance when the thickness of the first germanium layer is 77.08 nm; the first zinc sulfide layer is 90.33 nm; the second germanium layer is 267.52 nm; the second zinc sulfide layer is 118 nm; the third germanium layer is 74.02 nm; the third zinc sulfide layer is 90.68 nm; the ytterbium fluoride layer is 383.17 nm; the fourth zinc sulfide layer is 55.63 nm; and the lanthanum fluoride layer is 79.26 nm.

[0041] Secondly, the present invention provides a method for preparing the above-mentioned high-durability antireflection film in the infrared 3-5μm band of chalcogenide glass, comprising the following steps:

[0042] Step 1: Sequentially deposit a first germanium layer, a first zinc sulfide layer, a second germanium layer, a second zinc sulfide layer, a third germanium layer, a third zinc sulfide layer, a ytterbium fluoride layer, a fourth zinc sulfide layer, and a lanthanum fluoride layer on one side of the substrate.

[0043] Step 2: Repeat step 1 to deposit a film structure on the other side of the substrate.

[0044] Preferably, in step 1, the substrate is a chalcogenide glass substrate.

[0045] The inventors discovered that while chalcogenide glass substrates possess good infrared transmittance and chemical stability, their refractive index is relatively low. Further research revealed that by constructing the aforementioned film structure on a chalcogenide glass substrate, it is possible to significantly reduce reflection and improve light transmittance through interference effects while maintaining good transmittance.

[0046] Before step 1, there is also a substrate cleaning stage, in which the substrate surface is cleaned using a Hall ion source.

[0047] The inventors discovered through research that using a Hall ion source to clean the substrate can eliminate the surface oxide layer, making the surface cleaner and improving the stability of the coating.

[0048] Further optimization is achieved by using the Hall ion source parameters as follows when cleaning the substrate: neutralization current 0.5~0.7A, neutralization gas flow rate 8sccm, anode voltage 200~240V, anode current 1.8~2.2A, and argon gas flow rate 100%.

[0049] In practice, the parameters of the Hall ion source during substrate cleaning can be set according to actual needs. In a specific embodiment of the present invention, the neutralization current can be 0.5A, 0.6A, or 0.7A; the anode voltage can be 200V, 220V, or 240V; and the anode current can be 1.8A, 2.0A, or 2.2A.

[0050] Preferably, the germanium layer is prepared by electron beam heating evaporation, and the zinc sulfide layer, ytterbium fluoride layer, and lanthanum fluoride layer are prepared by resistance heating evaporation.

[0051] Preferably, when depositing the germanium layer, the evaporation rate of germanium is 4 Å / s.

[0052] Further optimization is achieved by using the following ion source parameters when depositing the germanium layer: neutralization current 0.4~0.6A, neutralization gas flow rate 8sccm, anode voltage 70~90V, anode current 0.6~0.8A, and argon gas flow rate 100%.

[0053] In practice, the ion source parameters during germanium layer preparation can be adjusted according to actual needs. In specific embodiments of the present invention, the neutralization current can be 0.4A, 0.5A, or 0.6A; the anode voltage can be 70V, 80V, or 90V; and the anode current can be 0.6A, 0.7A, or 0.8A.

[0054] Preferably, when depositing the zinc sulfide layer, the evaporation rate of the zinc sulfide is 6 Å / s.

[0055] Further optimization is achieved by using the following ion source parameters when depositing the zinc sulfide layer: neutralization current 0.4~0.6A, neutralization gas flow rate 8sccm, anode voltage 80~120V, anode current 0.8~1.2A, and argon gas flow rate 100%.

[0056] In practice, the ion source parameters for preparing the zinc sulfide layer can be adjusted according to actual needs. In a specific embodiment of the present invention, the neutralization current can be 0.4A, 0.5A, or 0.6A; the anode voltage can be 80V, 100V, or 120V; and the anode current can be 0.8A, 1.0A, or 1.2A.

[0057] Preferably, when depositing the ytterbium fluoride layer, the evaporation rate of the ytterbium fluoride is 5 Å / s.

[0058] Preferably, when depositing the lanthanum fluoride layer, the evaporation rate of the lanthanum fluoride is 6 Å / s.

[0059] Further optimization yielded the following ion source parameters for depositing the ytterbium fluoride and lanthanum fluoride layers: neutralization current 0.5~0.7A, neutralization gas flow rate 6~10sccm, anode voltage 110~150V, anode current 1.1~1.5A, argon flow rate 30%, and oxygen flow rate 70%.

[0060] In practice, the ion source parameters for preparing ytterbium fluoride and lanthanum fluoride layers can be adjusted according to actual needs. In specific embodiments of the present invention, the neutralization current can be 0.5A, 0.6A, or 0.7A; the anode voltage can be 110V, 130V, or 150V; and the anode current can be 1.1A, 1.3A, or 1.5A.

[0061] Preferably, in step 1, the coating vacuum degree is 4.5 × 10⁻⁶. -3 ~5.5×10 -3 Pa.

[0062] In practical applications, the coating vacuum degree can be adjusted according to actual needs. In a specific embodiment of the present invention, the coating vacuum degree can be 4.5 × 10⁻⁶. -3 Pa, 5.0 × 10 -3 Pa, 5.5 × 10 -3 Pa.

[0063] Preferably, in step 1, the coating temperature is 125~135℃.

[0064] In practical applications, the coating temperature can be adjusted according to actual needs. In specific embodiments of the present invention, the coating temperature can be 125℃, 130℃, or 135℃.

[0065] Preferably, after step 1, there is also a heat preservation and cooling stage.

[0066] Further optimization involves setting the insulation temperature to 125~135℃ and the insulation time to 30 minutes.

[0067] In practical applications, the insulation temperature and insulation duration can be adjusted according to actual needs. In a specific embodiment of the present invention, the insulation temperature can be 125℃, 130℃, or 135℃; the insulation duration can be 70min, 80min, or 90min.

[0068] Further optimization involves removing the product once the temperature drops by 50-70°C.

[0069] In practical applications, the cooling method can be selected according to actual needs, such as natural cooling or uniform cooling at a fixed cooling rate.

[0070] To make the technical problems, technical solutions and technical advantages of the present invention clearer, a detailed description will be given below with reference to specific examples. However, the scope of protection of the present invention is not limited to the following specific embodiments.

[0071] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0072] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0073] Example 1:

[0074] A method for preparing a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band includes the following steps:

[0075] Step 1: Clean the surfacing sheet and chalcogenide glass. Place the surfacing sheet and chalcogenide glass into the tooling fixture, and then hang the tooling fixture into the cavity of the vacuum coating machine. Set the temperature of the cavity to 130℃.

[0076] Step 2: Start the vacuum coating machine to draw a vacuum, achieving a vacuum level of 1.3 × 10⁻⁶ inside the machine. -3 At Pa, the ion source of the vacuum coating machine is started to clean the substrate and chalcogenide glass for 5 minutes. During substrate cleaning, the Hall ion source parameters are: neutralization current 0.6 A, neutralization gas flow rate 8 sccm, anode voltage 220 V, anode current 2.0 A, and argon flow rate 100%.

[0077] Step 3: Sequentially deposit a first germanium layer (77.08 nm thick), a first zinc sulfide layer (90.33 nm thick), a second germanium layer (267.52 nm thick), a second zinc sulfide layer (118 nm thick), a third germanium layer (74.02 nm thick), a third zinc sulfide layer (90.68 nm thick), a ytterbium fluoride layer (383.17 nm thick), a fourth zinc sulfide layer (55.63 nm thick), and a lanthanum fluoride layer (79.26 nm thick) on one side of the chalcogenide glass substrate. During deposition, the vacuum coating machine temperature was 130°C, and the vacuum degree was 5.0 × 10⁻⁶. -3 Pa.

[0078] When depositing the germanium layer, the evaporation rate of germanium is 4 Å / s, and the ion source parameters are: neutralization current 0.5 A, neutralization gas flow rate 8 sccm, anode voltage 80 V, anode current 0.7 A, and argon flow rate 100%.

[0079] When depositing the zinc sulfide layer, the evaporation rate of zinc sulfide is 6 Å / s, and the ion source parameters are: neutralization current 0.5 A, neutralization gas flow rate 8 sccm, anode voltage 100 V, anode current 1 A, and argon flow rate 100%.

[0080] When depositing a ytterbium fluoride layer, the evaporation rate of ytterbium fluoride is 5 Å / s, and when depositing a lanthanum fluoride layer, the evaporation rate of lanthanum fluoride is 6 Å / s.

[0081] The ion source parameters for depositing ytterbium fluoride and lanthanum fluoride layers are: neutralization current 0.6A, neutralization gas flow rate 8sccm, anode voltage 130V, anode current 1.3A, argon flow rate 30%, and oxygen flow rate 70%.

[0082] Step 4: After keeping warm at 130℃ for 30 minutes, allow it to cool naturally to 60℃ before removing it.

[0083] Step 5: Repeat steps 1-4 to deposit a film structure on the other side of the chalcogenide glass substrate, thus obtaining a high-durability antireflection film for the chalcogenide glass infrared 3-5μm band.

[0084] Example 2:

[0085] Step 1: Clean the substrate and chalcogenide glass. Place the substrate and chalcogenide glass into the tooling fixture, and then hang the tooling fixture into the cavity of the vacuum coating machine. Set the temperature of the cavity to 125℃.

[0086] Step 2: Start the vacuum coating machine to draw a vacuum, achieving a vacuum level of 1.3 × 10⁻⁶ inside the machine. -3 At Pa, the ion source of the vacuum coating machine is started to clean the substrate and chalcogenide glass for 5 minutes. During substrate cleaning, the Hall ion source parameters are: neutralization current 0.5A, neutralization gas flow rate 8 sccm, anode voltage 200V, anode current 1.8A, and argon flow rate 100%.

[0087] Step 3: On one side of the chalcogenide glass substrate, a first germanium layer with a thickness of 74.08 nm, a first zinc sulfide layer with a thickness of 87.33 nm, a second germanium layer with a thickness of 264.52 nm, a second zinc sulfide layer with a thickness of 115 nm, a third germanium layer with a thickness of 71.02 nm, a third zinc sulfide layer with a thickness of 87.68 nm, a ytterbium fluoride layer with a thickness of 380.17 nm, a fourth zinc sulfide layer with a thickness of 52.63 nm, and a lanthanum fluoride layer with a thickness of 76.26 nm are sequentially deposited. During the deposition process, the temperature of the vacuum coating machine is 125℃, and the vacuum degree of the coating is 4.5 × 10⁻⁶. -3 Pa.

[0088] When depositing the germanium layer, the evaporation rate of germanium is 4 Å / s, and the ion source parameters are: neutralization current 0.4 A, neutralization gas flow rate 8 sccm, anode voltage 70 V, anode current 0.6 A, and argon flow rate 100%.

[0089] When depositing the zinc sulfide layer, the evaporation rate of zinc sulfide is 6 Å / s, and the ion source parameters are: neutralization current 0.4 A, neutralization gas flow rate 8 sccm, anode voltage 80 V, anode current 0.8 A, and argon flow rate 100%.

[0090] When depositing a ytterbium fluoride layer, the evaporation rate of ytterbium fluoride is 5 Å / s, and when depositing a lanthanum fluoride layer, the evaporation rate of lanthanum fluoride is 6 Å / s.

[0091] The ion source parameters for depositing ytterbium fluoride and lanthanum fluoride layers are: neutralization current 0.5A, neutralization gas flow rate 6sccm, anode voltage 110V, anode current 1.1A, argon flow rate 30%, and oxygen flow rate 70%.

[0092] Step 4: After keeping warm at 125℃ for 20 minutes, allow it to cool naturally to 50℃ before removing it.

[0093] Step 5: Repeat steps 1-4 to deposit a film structure on the other side of the chalcogenide glass substrate, thus obtaining a high-durability antireflection film for the chalcogenide glass infrared 3-5μm band.

[0094] Example 3:

[0095] Step 1: Clean the substrate and chalcogenide glass. Place the substrate and chalcogenide glass into the tooling fixture, and then hang the tooling fixture into the cavity of the vacuum coating machine. Set the temperature of the cavity to 135℃.

[0096] Step 2: Start the vacuum coating machine to draw a vacuum, achieving a vacuum level of 1.3 × 10⁻⁶ inside the machine. -3 At Pa, the ion source of the vacuum coating machine is started to clean the substrate and chalcogenide glass for 5 minutes. During substrate cleaning, the Hall ion source parameters are: neutralization current 0.7A, neutralization gas flow rate 8 sccm, anode voltage 240V, anode current 2.2A, and argon flow rate 100%.

[0097] Step 3: On one side of the chalcogenide glass substrate, a first germanium layer with a thickness of 80.08 nm, a first zinc sulfide layer with a thickness of 93.33 nm, a second germanium layer with a thickness of 270.52 nm, a second zinc sulfide layer with a thickness of 121 nm, a third germanium layer with a thickness of 77.02 nm, a third zinc sulfide layer with a thickness of 93.68 nm, a ytterbium fluoride layer with a thickness of 386.17 nm, a fourth zinc sulfide layer with a thickness of 55.63 nm, and a lanthanum fluoride layer with a thickness of 82.26 nm are sequentially deposited. During the deposition, the temperature of the vacuum coating machine is 135℃, and the vacuum degree of the coating is 5.5 × 10⁻⁶. -3 Pa.

[0098] When depositing the germanium layer, the evaporation rate of germanium is 4 Å / s, and the ion source parameters are: neutralization current 0.6 A, neutralization gas flow rate 8 sccm, anode voltage 90 V, anode current 0.8 A, and argon gas flow rate 100%.

[0099] When depositing the zinc sulfide layer, the evaporation rate of zinc sulfide is 6 Å / s, and the ion source parameters are: neutralization current 0.6 A, neutralization gas flow rate 8 sccm, anode voltage 120 V, anode current 1.2 A, and argon flow rate 100%.

[0100] When depositing a ytterbium fluoride layer, the evaporation rate of ytterbium fluoride is 5 Å / s, and when depositing a lanthanum fluoride layer, the evaporation rate of lanthanum fluoride is 6 Å / s.

[0101] The ion source parameters for depositing ytterbium fluoride and lanthanum fluoride layers are: neutralization current 0.7A, neutralization gas flow rate 10sccm, anode voltage 150V, anode current 1.5A, argon flow rate 30%, and oxygen flow rate 70%.

[0102] Step 4: After heat preservation at 135°C for 40 min, naturally cool to 70°C and then take out.

[0103] Step 5: Repeat Steps 1 - 4 to deposit a film system structure on the other side of the chalcogenide glass substrate, and then a high - durability antireflection film for the 3 - 5μm band of infrared light of chalcogenide glass is obtained.

[0104] Comparative Example 1:

[0105] The difference from Example 1 is that in Step 3, the lanthanum fluoride layer is not deposited.

[0106] Comparative Example 2:

[0107] The difference from Example 1 is that in Step 3, the ytterbium fluoride layer and the fourth zinc sulfide layer are not deposited.

[0108] Comparative Example 3:

[0109] The difference from Example 1 is that in Step 3, on one side of the chalcogenide glass substrate, a first germanium layer, a first zinc sulfide layer, a second germanium layer, a second zinc sulfide layer, an ytterbium fluoride layer, a third zinc sulfide layer, and a lanthanum fluoride layer are deposited in sequence.

[0110] The high - durability antireflection films for the 3 - 5μm band of infrared light of chalcogenide glass prepared in Examples 1 - 3 and Comparative Examples 1 - 3 are rubbed 50 times (25 back - and - forth) with a rubber friction head wrapped with degreasing cloth under a pressure of 4.9 N, and check whether there are damage marks such as scratches. If there are no such marks, it is qualified; if there are such marks, it is unqualified. The test results are shown in Table 1 below.

[0111] Table 1 - Pressure test of the high - durability antireflection films for the 3 - 5μm band of infrared light of chalcogenide glass prepared in Examples 1 - 3 and Comparative Examples 1 - 3

[0112]

[0113] As can be seen from Table 1, the film system structure provided by the present invention has more excellent wear resistance and corrosion resistance.

[0114] Figures 1-3 To test the transmittance curve spectra of the high - durability antireflection films for the 3 - 5μm band of infrared light of chalcogenide glass prepared in Examples 1 - 3 using a spectrometer. Figure 1 As can be seen, the transmittance of the high - durability antireflection film for the 3 - 5μm band of infrared light of chalcogenide glass prepared in Example 1 is 98.19% in the 3 - 5μm band of infrared light, and the peak value can be as high as 98.87%. Figure 2 As can be seen, the transmittance of the high - durability antireflection film for the 3 - 5μm band of infrared light of chalcogenide glass prepared in Example 2 is 98.10% in the 3 - 5μm band of infrared light, and the peak value can be as high as 99.06%. Figure 3It can be seen that the high-durability antireflective coating of chalcogenide glass in the infrared 3-5μm band prepared in Example 3 has a transmittance of 98.14% in the infrared 3-5μm band, with a peak value as high as 98.80%.

[0115] Figures 4-5 This is a transmittance spectrum of the high-durability antireflective coatings in the infrared 3-5 μm band of chalcogenide glass prepared in Comparative Examples 2-3 of this invention. Figure 4 It can be seen that the high-durability antireflective coating for chalcogenide glass prepared in Comparative Example 2 has a transmittance of 95.58% and a peak value of 96.59% in the 3-5μm infrared band. Figure 5 It can be seen that the high-durability antireflective coating of chalcogenide glass in the infrared 3-5μm band prepared in Comparative Example 3 has a transmittance of 97.5% and a peak value of 98.83% in the infrared 3-5μm band.

[0116] contrast Figures 1-5 It is evident that the membrane structure provided by this invention has superior transmission performance and broad application prospects.

[0117] The above-described embodiments are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope of the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band, characterized in that, The film structure includes a film system symmetrically arranged on both sides of a chalcogenide glass substrate. The film system consists of a first germanium layer, a first zinc sulfide layer, a second germanium layer, a second zinc sulfide layer, a third germanium layer, a third zinc sulfide layer, a ytterbium fluoride layer, a fourth zinc sulfide layer, and a lanthanum fluoride layer, arranged sequentially from the inside to the outside of the chalcogenide glass substrate. The thickness of the first germanium layer is 77.08±3 nm; the thickness of the first zinc sulfide layer is 90.33±3 nm; the thickness of the second germanium layer is 267.52±3 nm; the thickness of the second zinc sulfide layer is 118±3 nm; the thickness of the third germanium layer is 74.02±3 nm; the thickness of the third zinc sulfide layer is 90.68±3 nm; the thickness of the ytterbium fluoride layer is 383.17±3 nm; the thickness of the fourth zinc sulfide layer is 55.63±3 nm; and the thickness of the lanthanum fluoride layer is 79.26±3 nm.

2. The method for preparing a high-durability antireflective coating in the infrared 3-5μm band of chalcogenide glass as described in claim 1, characterized in that, Includes the following steps: Step 1: Sequentially deposit a first germanium layer, a first zinc sulfide layer, a second germanium layer, a second zinc sulfide layer, a third germanium layer, a third zinc sulfide layer, a ytterbium fluoride layer, a fourth zinc sulfide layer, and a lanthanum fluoride layer on one side of the substrate. Step 2: Repeat step 1 to deposit a film structure on the other side of the substrate.

3. The method for preparing a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band as described in claim 2, characterized in that, Before step 1, there is also a substrate cleaning stage, in which the substrate surface is cleaned using a Hall ion source.

4. The method for preparing a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band as described in claim 3, characterized in that, When cleaning the substrate, the Hall ion source parameters are as follows: neutralization current 0.5~0.7A, neutralization gas flow rate 8sccm, anode voltage 200~240V, anode current 1.8~2.2A, and argon gas flow rate 100%.

5. The method for preparing a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band as described in claim 2, characterized in that, Germanium layers were prepared by electron beam heating evaporation; zinc sulfide, ytterbium fluoride, and lanthanum fluoride layers were prepared by resistance heating evaporation.

6. The method for preparing a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band as described in claim 2 or 5, characterized in that, Germanium, zinc sulfide, ytterbium fluoride, and lanthanum fluoride layers were prepared using an ion-assisted deposition process.

7. The method for preparing a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band as described in claim 2, characterized in that, In step 1, the coating vacuum degree is 4.5 × 10⁻⁶. -3 ~5.5×10 -3 Pa; Coating temperature is 125~135℃.

8. The method for preparing a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band as described in claim 2 or 5, characterized in that, When depositing a germanium layer, the evaporation rate of germanium is 4 Å / s; when depositing a zinc sulfide layer, the evaporation rate of zinc sulfide is 6 Å / s; when depositing a ytterbium fluoride layer, the evaporation rate of ytterbium fluoride is 5 Å / s; and when depositing a lanthanum fluoride layer, the evaporation rate of lanthanum fluoride is 6 Å / s.

9. The method for preparing a high-durability antireflective coating for chalcogenide glass in the infrared 3-5μm band as described in claim 2, characterized in that, After step 1, there are also heat preservation and cooling stages; The heat preservation temperature during the heat preservation stage is 125~135℃, and the heat preservation time is 20~40 minutes; it can be removed when the temperature drops to 50~70℃.

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