Preparation method of double-band antireflection film plated on zinc selenide substrate
By depositing six alternating layers of YF3 and ZnS films on a zinc selenide substrate, the problem of insufficient dual-band transmittance in the prior art was solved, and the preparation of antireflective films with high transmittance and good adhesion was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 安徽光智科技有限公司
- Filing Date
- 2023-10-27
- Publication Date
- 2026-06-05
AI Technical Summary
Existing technologies make it difficult to prepare antireflective films that meet dual-band transmittance requirements on zinc selenide substrates.
A method for depositing six layers on a zinc selenide substrate, including the alternating deposition of YF3 and ZnS layers, is employed. By controlling the thickness of each layer and using ion source-assisted evaporation, the adhesion and transmission performance of the layers are ensured.
It achieved a transmittance of over 98% in the 1064nm and 7.7-10.5μm bands, with good film adhesion, and withstood various environmental tests without peeling or cracking.
Smart Images
Figure CN117448751B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of optics, and more specifically to a method for preparing a dual-band antireflection film deposited on a zinc selenide substrate. Background Technology
[0002] In the field of infrared optical coating, zinc selenide (ZnSe) windows have a wide transmission band and are water resistant. Zinc selenide windows are widely used in spectroscopic prisms, transmission windows and lenses of infrared spectrometers, spectrophotometers and infrared devices.
[0003] Chinese patent document CN116240498A, published on June 9, 2023, discloses a method for preparing a 1064nm infrared antireflection film system on a zinc selenide substrate, which belongs to the category of depositing single-band antireflection films on zinc selenide substrates. It is necessary to further develop a method for depositing dual-band antireflection films on zinc selenide substrates based on this method. Summary of the Invention
[0004] In view of the problems existing in the background art, the purpose of this disclosure is to provide a method for preparing a dual-band antireflection film deposited on a zinc selenide substrate, which can achieve the requirement of high transmittance in both infrared bands.
[0005] Therefore, a method for preparing a dual-band antireflective coating on a zinc selenide substrate includes the following steps: S1, cleaning the surfaces of the zinc selenide substrate (which serves as the lens) and the product, wherein the thickness of the substrate is 0.9-1.5 mm; S2, placing the cleaned lens into a fixture, and then hanging the fixture with the lens in place into the cavity of a vacuum coating machine, wherein the temperature of the cavity is set to 150°C; S3, starting the vacuum coating machine to evacuate the vacuum, achieving a vacuum level of 1×10⁻⁶. -3S1, turn on the ion source of the vacuum coating machine for cleaning, the cleaning time is 6 minutes, the ion source anode voltage is 220V, the anode current is 1.2-1.5A, and the emitter current is 1.3-1.5A; S4, maintain the aforementioned vacuum level, deposit the first YF3 film layer on the first surface of the lens, the deposition rate of the first YF3 film layer is 0.6nm / s, and the film thickness of the first YF3 film layer is controlled to be 59.8nm±2nm, with ion source assisted evaporation; S5, on the coating... A first ZnS film is deposited on a first YF3 film at a deposition rate of 0.8 nm / s, with a thickness of 57.8 nm ± 2 nm, using ion source-assisted deposition. S6: A second YF3 film is deposited on the deposited first ZnS film at a deposition rate of 0.6 nm / s, with a thickness of 880 nm ± 5 nm, using ion source-assisted deposition. S7: [Further details about the second YF3 film are needed for accurate translation.] A second ZnS film is deposited by vapor deposition at a rate of 0.8 nm / s, with a thickness controlled at 126 nm ± 4 nm, using ion source-assisted vapor deposition. In step S8, a third YF3 film is deposited on the deposited second ZnS film at a rate of 0.6 nm / s, with a thickness controlled at 75.6 nm ± 3 nm, using ion source-assisted vapor deposition. In step S9, a third ZnS film is deposited on the deposited third YF3 film. The deposition rate of the third ZnS film is 0.8 nm / s, and the thickness of the third ZnS film is controlled to be 50 nm ± 2 nm. Ion source assisted evaporation is used. S10: After the deposition is completed, the first coated lens is taken out after the vacuum chamber is cooled to below 60°C. S11: Repeat steps S1 to S10 to deposit the first YF3 film, the first ZnS film, the second YF3 film, the second ZnS film, the third YF3 film, and the third ZnS film on the opposite second side of the lens in sequence.
[0006] The beneficial effects of this disclosure are as follows: In the preparation method of depositing a dual-band antireflection film on a zinc selenide substrate according to this disclosure, a first YF3 film layer with a thickness of 59.8 nm ± 2 nm, a first ZnS film layer with a thickness of 57.8 nm ± 2 nm, a second YF3 film layer with a thickness of 880 nm ± 5 nm, a second ZnS film layer with a thickness of 126 nm ± 4 nm, a third YF3 film layer with a thickness of 75.6 nm ± 3 nm, and a third ZnS film layer with a thickness of 50 nm ± 2 nm are deposited on the first and second surfaces opposite to the zinc selenide substrate used as a lens. The six film layers on the first surface and the six film layers on the second surface will serve as the inner and outer film layers of the lens product, respectively. Both the inner and outer film layers are antireflection and anti-reflection films. Based on the 1064 nm band (near-infrared band) test and the 7.7-10.5 μm band (far-infrared band) test of the co-coated film, the transmittance can reach more than 98%. In other words, the combination of the inner and outer membrane layers can meet the dual-band transmittance requirements. Attached Figure Description
[0007] Figure 1 This is a schematic diagram of a structure in which a dual-band antireflection film is deposited on both sides of a substrate including a zinc selenide substrate and a product, according to the preparation method of the zinc selenide substrate deposited on the substrate.
[0008] Figure 2 This is a graph showing the transmittance of the dual-band antireflective coating deposited on both sides of the substrate in Example 1 at the 1064nm wavelength.
[0009] Figure 3 This is a graph showing the transmittance of the dual-band antireflective coating deposited on both sides of the substrate in Example 1 in the 7.7-10.5μm infrared band. Detailed Implementation
[0010] The accompanying drawings illustrate embodiments of this disclosure, and it will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.
[0011] [Preparation method of dual-band antireflection coating deposited on zinc selenide substrate]
[0012] The method for preparing a dual-band antireflective coating deposited on a zinc selenide substrate according to this disclosure includes the following steps:
[0013] S1, the surface of the co-plated sheet, which serves as the zinc selenide substrate for the lens, and the product are cleaned. The thickness of the co-plated sheet is 0.9-1.5mm.
[0014] S2, Place the cleaned lens into the fixture, and hang the fixture with the lens in it into the cavity of the vacuum coating machine. Set the temperature of the cavity to 150℃.
[0015] S3, the vacuum coating machine starts drawing a vacuum, and the vacuum level reaches 1×10⁻⁶. -3 Pa, turn on the auxiliary coating ion source of the vacuum coating machine for cleaning. The cleaning time is 6 minutes. The anode voltage of the ion source is 220V, the anode current is 1.2-1.5A, and the emitter current is 1.3-1.5A.
[0016] S4, maintaining the aforementioned vacuum level, deposit a first YF3 film layer on the first surface of the lens by evaporation. The deposition rate of the first YF3 film layer is 0.6 nm / s, and the film thickness of the first YF3 film layer is controlled to be 59.8 nm ± 2 nm. Ion source assisted evaporation.
[0017] S5, deposit a first ZnS film on the deposited first YF3 film layer. The deposition rate of the first ZnS film layer is 0.8 nm / s, and the film thickness of the first ZnS film layer is controlled to be 57.8 nm ± 2 nm. Ion source assisted evaporation.
[0018] S6, a second YF3 film is deposited on the first ZnS film layer by vapor deposition. The deposition rate of the second YF3 film layer is 0.6 nm / s, and the thickness of the second YF3 film layer is controlled to be 880 nm ± 5 nm. Ion source assisted vapor deposition.
[0019] S7, a second ZnS film is deposited on the deposited second YF3 film. The deposition rate of the second ZnS film is 0.8 nm / s, and the thickness of the second ZnS film is controlled to be 126 nm ± 4 nm. Ion source assisted evaporation.
[0020] S8, a third YF3 film is deposited on the deposited second ZnS film. The deposition rate of the third YF3 film is 0.6 nm / s, and the thickness of the third YF3 film is controlled to be 75.6 nm ± 3 nm. Ion source assisted evaporation.
[0021] S9, a third ZnS film is deposited on the deposited third YF3 film. The deposition rate of the third ZnS film is 0.8 nm / s, and the thickness of the third ZnS film is controlled to be 50 nm ± 2 nm. Ion source assisted evaporation.
[0022] S10, after the coating is completed, wait for the vacuum chamber to cool down to below 60°C and then take out the first coated lens;
[0023] S11, repeat steps S1 to S10, and sequentially deposit the first YF3 film, the first ZnS film, the second YF3 film, the second ZnS film, the third YF3 film, and the third ZnS film on the opposite second side of the lens.
[0024] In the preparation method of depositing a dual-band antireflective coating on a zinc selenide substrate according to the present disclosure, a first YF3 film layer with a thickness of 59.8 nm ± 2 nm, a first ZnS film layer with a thickness of 57.8 nm ± 2 nm, a second YF3 film layer with a thickness of 880 nm ± 5 nm, a second ZnS film layer with a thickness of 126 nm ± 4 nm, a third YF3 film layer with a thickness of 75.6 nm ± 3 nm, and a third ZnS film layer with a thickness of 50 nm ± 2 nm are deposited on the first and second surfaces opposite to the zinc selenide substrate used as a lens. The six film layers on the first surface and the six film layers on the second surface serve as the inner and outer film layers of the lens product, respectively. Both the inner and outer film layers are antireflective and anti-reflective coatings. Based on the 1064 nm band (near-infrared band) test and the 7.7-10.5 μm band (far-infrared band) test of the co-coated film, the transmittance can reach more than 98%. In other words, the combination of the inner and outer membrane layers can meet the dual-band transmittance requirements.
[0025] In the method for preparing a dual-band antireflective coating deposited on a zinc selenide substrate according to the present disclosure, the total thickness of the six film layers deposited on each of the first and second surfaces opposite to the first and second surfaces of the zinc selenide substrate serving as a lens is 1249.2 nm ± 18 nm.
[0026] The surface cleaning in step S1 helps improve the surface condition of the first and second sides of the substrate and the product, and helps to improve the bonding performance of the six-layer film with the corresponding sides of the substrate and the product.
[0027] The temperature of the cavity in step S2 helps to eliminate stress on each side of the substrate and the product (i.e., each of the first and second sides) and the first YF3 film layer, while also facilitating the growth of antireflective and anti-reflective films on each side of the substrate and the product.
[0028] Step S3 uses an ion source for cleaning. The bombardment and sputtering effects of argon ions ionized by the working gas argon will cause impurities, oil molecules, and oxides adsorbed on the surface of the substrate of the substrate and the coated wafer and the product to detach from the substrate surface, thereby greatly improving the interface state and helping to improve the bonding performance between the first YF3 film layer and the zinc selenide substrate. At the same time, the bombardment of the zinc selenide substrate by argon ions can heat the surface of the zinc selenide substrate, which helps the growth of the first YF3 film layer and reduces the growth stress of the first YF3 film layer.
[0029] In steps S4 to S9, ion source-assisted evaporation helps the corresponding film layer grow, improves adhesion and hardness, and reduces film layer stress through ion bombardment.
[0030] In steps S3 to S9, the middle pair of YF3 / ZnS films has the largest thickness, while the thicknesses of the upper and lower pairs of YF3 / ZnS films are not significantly different. However, the thickness of the middle pair of YF3 / ZnS films is on a completely different scale than that of the upper and lower pairs of YF3 / ZnS films. This allows for a transition from the zinc selenide substrate to the thicker pair of YF3 / ZnS films by using a thin pair of YF3 / ZnS films as a transition layer. This is beneficial for buffering and releasing the stress between the two adjacent pairs of films and for reducing the thickness of the six films on each surface of the zinc selenide substrate.
[0031] In one example, in step S1, the thickness of the plating sheet is 1.0 mm.
[0032] In one example, in step S1, the lens surface is cleaned using ultrasound or by hand.
[0033] In one example, in step S3, the anode current is 1.2A and the emitter current is 1.5A.
[0034] In one example, in step S3, the ion source is a Hall ion source, and argon is used as the working gas.
[0035] In one example, in step S4, the thickness of the first YF3 film is controlled to be 59.8 nm; in step S5, the thickness of the first ZnS film is controlled to be 57.8 nm; in step S6, the thickness of the second YF3 film is controlled to be 880 nm; in step S7, the thickness of the second ZnS film is controlled to be 126 nm; in step S8, the thickness of the third YF3 film is controlled to be 75.6 nm; and in step S9, the thickness of the third ZnS film is controlled to be 50 nm.
[0036] In one example, in steps S4, S6, and S8, a neutralizer is provided for the ion source. The parameters of the neutralizer are: neutralization current of 0.6A, neutralization gas is formed using argon, and the flow rate of the neutralization gas is 8 sccm. The anode voltage of the ion source is 130V, the anode current is 1.3A, and argon and oxygen are used as working gases, with an argon flow rate of 30 sccm and an oxygen flow rate of 70 sccm. The use of oxygen increases the compactness of the YF3 film.
[0037] In one example, in steps S5, S7 and S9, a neutralizer is provided for the ion source. The parameters of the neutralizer are: neutralization current of 0.5A, neutralization gas is formed by argon, and the flow rate of the neutralization gas is 8 sccm. The anode voltage of the ion source is 100V, the anode current is 1.0A, argon is used as the working gas, and the flow rate of the argon gas is 100 sccm.
[0038] In one example, in steps S4 to S9, the vapor deposition is performed using resistance heating evaporation.
[0039] [test]
[0040] Example 1
[0041] The preparation method for depositing a dual-band antireflection film on a zinc selenide substrate adopts the following steps:
[0042] S1, the surface of the zinc selenide substrate used as the lens and the surface of the product are cleaned by ultrasonic cleaning. The thickness of the substrate is 1.0mm.
[0043] S2, Place the cleaned lens into the fixture, and hang the fixture with the lens in it into the cavity of the vacuum coating machine. The temperature of the cavity is set to 150℃. The vacuum coating machine is a Hall ion source with a neutralizer manufactured and sold by Chengdu Xiwoke Vacuum Technology Co., Ltd. The Hall ion source with a neutralizer was purchased from Boton Optoelectronics Technology Co., Ltd.
[0044] S3, the vacuum coating machine starts drawing a vacuum, and the vacuum level reaches 1×10⁻⁶. -3 Pa, turn on the ion source of the auxiliary coating of the vacuum coating machine for cleaning. The cleaning time is 6 minutes. The anode voltage of the ion source is 220V, the anode current is 1.2A, and the emitter current is 1.5A. Argon is used as the working gas.
[0045] S4, maintaining the aforementioned vacuum level, deposit a first YF3 film layer on the first surface of the lens by vapor deposition. The deposition rate of the first YF3 film layer is 0.6 nm / s, and the film thickness of the first YF3 film layer is controlled to be 59.8 nm. Ion source assisted vapor deposition is used, and resistance heating evaporation is employed for the vapor deposition.
[0046] S5, deposit a first ZnS film on the deposited first YF3 film layer. The deposition rate of the first ZnS film layer is 0.8 nm / s, and the film thickness of the first ZnS film layer is controlled to be 57.8 nm. Ion source assisted evaporation and resistance heating evaporation is used for evaporation.
[0047] S6, a second YF3 film layer is deposited on the first ZnS film layer. The deposition rate of the second YF3 film layer is 0.6 nm / s, and the film thickness of the second YF3 film layer is controlled to be 880 nm. Ion source assisted evaporation is used, and resistance heating evaporation is used for evaporation.
[0048] S7, a second ZnS film is deposited on the deposited second YF3 film. The deposition rate of the second ZnS film is 0.8 nm / s, and the thickness of the second ZnS film is controlled to be 126 nm. Ion source assisted evaporation is used, and resistance heating evaporation is employed for the evaporation.
[0049] S8, a third YF3 film layer is deposited on the deposited second ZnS film layer. The deposition rate of the third YF3 film layer is 0.6 nm / s, and the film thickness of the third YF3 film layer is controlled to be 75.6 nm. Ion source assisted evaporation and resistance heating evaporation is used for evaporation.
[0050] S9, a third ZnS film is deposited on the deposited third YF3 film. The deposition rate of the third ZnS film is 0.8 nm / s, and the thickness of the third ZnS film is controlled to be 50 nm. Ion source assisted evaporation is used, and resistance heating evaporation is used for evaporation.
[0051] S10, after the coating is completed, wait for the vacuum chamber to cool to 60°C and then take out the first coated lens;
[0052] S11, repeat steps S1 to S10, and sequentially deposit the first YF3 film, the first ZnS film, the second YF3 film, the second ZnS film, the third YF3 film, and the third ZnS film on the opposite second side of the lens.
[0053] In steps S4, S6 and S8, a neutralizer is provided for the ion source. The parameters of the neutralizer are: neutralization current of 0.6A, neutralization gas is formed by argon, and the flow rate of the neutralization gas is 8 sccm. The anode voltage of the ion source is 130V, the anode current is 1.3A, argon and oxygen are used as working gases, the flow rate of argon is 30 sccm and the flow rate of oxygen is 70 sccm.
[0054] In steps S5, S7 and S9, a neutralizer is provided for the ion source. The parameters of the neutralizer are: neutralization current of 0.5A, neutralization gas is formed by argon, and the flow rate of the neutralization gas is 8 sccm. The anode voltage of the ion source is 100V, the anode current is 1.0A, argon is used as the working gas, and the flow rate of the argon gas is 100 sccm.
[0055] The structure of the lens prepared in Example 1, with six layers of film coated on each side, is as follows: Figure 1 As shown in the diagram, Figure 2 This is a graph showing the transmittance of the dual-band antireflective coating deposited on both sides of the substrate in Example 1 at the 1064nm wavelength. Figure 3 This is a graph showing the transmittance of the dual-band antireflective coating deposited on both sides of the substrate in Example 1 in the 7.7-10.5 μm infrared band. From... Figure 2 It can be seen that in the 1064nm band, the transmittance (arithmetic mean) can reach over 98%. From... Figure 2 It can be seen that in the 7.7-10.5μm band, the transmittance (arithmetic mean) can reach over 98%.
[0056] In accordance with the content of GJB2485-95 General Specification for Optical Coatings, the overall performance of the substrate and the six layers of film on each surface were inspected.
[0057] Water immersion test: The substrate prepared in Example 1, along with the six-layer film deposited on both sides, was subjected to a 10-minute water immersion test using tap water. No six-layer film was found to detach from the substrate or crack on any side.
[0058] Adhesion test: After the water immersion and salt spray tests were completed, 3M tape was applied to the third ZnS film layer on each side of the coated sheet by hand and the tape was pulled in the opposite direction to the adhesive end. The six film layers were not pulled up.
[0059] The water immersion test and the tape pulling test showed that the adhesion of the six film layers on both sides of the substrate was good.
[0060] Thermal shock test: The six-layer film on each side of the substrate was subjected to thermal shock for 24 hours in a high and low temperature chamber in the range of -40℃ to 85℃. No six-layer film was found to peel off from the substrate or crack on each side of the substrate.
[0061] Constant temperature and humidity test: 48 hours at 50℃ and 95% relative humidity in a constant temperature and humidity chamber. No six-layer film was found to peel off from the substrate, nor was any cracking of the six-layer film on the substrate observed.
[0062] Salt spray test: After 48 hours of neutral salt spray test, no six-layer film was found to peel off from the substrate or crack on the substrate.
[0063] Low temperature test: In the low temperature chamber, at -40℃ for 48 hours, no six-layer film was found to peel off from the substrate or crack on the substrate.
[0064] High temperature test: At a high temperature of 85℃ for 48 hours, no six-layer film was found to peel off from the substrate or crack on the substrate.
[0065] Several exemplary embodiments have been described in detail above, but this document is not intended to limit itself to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.
Claims
1. A method for preparing a dual-band antireflective coating deposited on a zinc selenide substrate, comprising the following steps: S1, the surface of the zinc selenide substrate used as the lens and the surface of the product are cleaned by ultrasonic cleaning. The thickness of the substrate is 1.0mm. S2, Place the cleaned lens into the fixture, and hang the fixture with the lens in it into the cavity of the vacuum coating machine. Set the temperature of the cavity to 150℃. S3, the vacuum coating machine starts drawing a vacuum, and the vacuum level reaches 1×10⁻⁶. -3 Pa, turn on the auxiliary coating ion source of the vacuum coating machine for cleaning. The cleaning time is 6 minutes. The ion source has an anode voltage of 220V, an anode current of 1.2A, and an emitter current of 1.5A. The ion source is a Hall ion source, and argon is used as the working gas. S4, maintaining the aforementioned vacuum level, deposit a first YF3 film layer on the first surface of the lens by evaporation. The deposition rate of the first YF3 film layer is 0.6 nm / s, and the film thickness of the first YF3 film layer is controlled to be 59.8 nm. Ion source assisted evaporation. S5, deposit a first ZnS film on the deposited first YF3 film layer by vapor deposition. The deposition rate of the first ZnS film layer is 0.8 nm / s, and the thickness of the first ZnS film layer is controlled to be 57.8 nm. Ion source assisted vapor deposition. S6, a second YF3 film is deposited on the first ZnS film layer by vapor deposition. The deposition rate of the second YF3 film layer is 0.6 nm / s, and the film thickness of the second YF3 film layer is controlled to be 880 nm. Ion source assisted vapor deposition. S7, a second ZnS film is deposited on the deposited second YF3 film. The deposition rate of the second ZnS film is 0.8 nm / s, and the thickness of the second ZnS film is controlled to be 126 nm. Ion source assisted evaporation. S8, a third YF3 film is deposited on the deposited second ZnS film. The deposition rate of the third YF3 film is 0.6 nm / s, and the thickness of the third YF3 film is controlled to be 75.6 nm. Ion source assisted evaporation. S9, a third ZnS film is deposited on the deposited third YF3 film. The deposition rate of the third ZnS film is 0.8 nm / s, and the thickness of the third ZnS film is controlled to be 50 nm. Ion source assisted evaporation. S10, after the coating is completed, wait for the vacuum chamber to cool to 60°C and then take out the first coated lens; S11, repeat steps S1 to S10, and sequentially deposit the first YF3 film, the first ZnS film, the second YF3 film, the second ZnS film, the third YF3 film, and the third ZnS film on the opposite second side of the lens. Based on tests of the 1064nm band and the 7.7-10.5μm band of the substrate, the arithmetic mean transmittance of the substrate in the 1064nm band is 99.9552%, and the arithmetic mean transmittance of the substrate in the 7.7-10.5μm band is 99.3506%. in, In steps S4, S6 and S8, a neutralizer is provided for the ion source. The parameters of the neutralizer are: neutralization current of 0.6A, neutralization gas is formed by argon, and the flow rate of the neutralization gas is 8 sccm. The anode voltage of the ion source is 130V, the anode current is 1.3A, argon and oxygen are used as working gases, the flow rate of argon is 30 sccm and the flow rate of oxygen is 70 sccm. In steps S5, S7 and S9, a neutralizer is provided for the ion source. The parameters of the neutralizer are: neutralization current of 0.5A, neutralization gas is formed by argon, and the flow rate of the neutralization gas is 8 sccm. The anode voltage of the ion source is 100V, the anode current is 1.0A, argon is used as the working gas, and the flow rate of the argon gas is 100 sccm. In steps S4 to S9, the vapor deposition is carried out using resistance heating evaporation.