A wideband ultra-low reflection coating process with large incident angle

Abstract

The application discloses a kind of wideband ultra-low reflection coating processes of big incident angle, first the surface of aspheric glass substrate is pretreated, then from bottom to top successively coated to form silica film layer, tantalum pentoxide film layer I, silicon aluminum oxide film layer I, tantalum pentoxide film layer II, silicon aluminum oxide film layer II, tantalum pentoxide film layer III, silicon aluminum oxide film layer III, tantalum pentoxide film layer IV, yttrium doped magnesium fluoride barium film layer, post-processing can be obtained.The lens obtained by coating according to the coating process of the application on the surface of aspheric glass substrate can be used for automobile lens, sports camera, mobile phone lens and other lens manufacturing.The application solves the problems of uneven coating, high reflectivity and other problems of existing coated glass, changes the problems of glare, ghost image and other problems of lens optical film in use at large incident angle, and has excellent corrosion resistance.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a wide-bandwidth ultra-low reflection coating process with a large incident angle. Background Technology

[0002] High-pixel fixed-focus lenses used in automotive lenses, action cameras, mobile phones, etc., are composed of multiple high-precision optical glass spherical and aspherical lenses. When strong light enters the lens, it is repeatedly refracted and reflected on the surface of each lens, forming messy light. Finally, it shines on the CMOS sensor and is captured, forming flare and ghosting in the image, which is more obvious in complex environments such as strong light and backlight.

[0003] Taking mobile phones as an example, with the popularization of mobile phones, people's requirements for various performance aspects of mobile phones are gradually increasing, especially the photo and video performance of mobile phone lenses. They are required not only to take high-quality, high-resolution photos, but also to be able to adapt to various working environments.

[0004] However, light undergoes reflection and refraction when passing through different media. Modern mobile phone lenses have more complex structures and more lenses, resulting in more reflections and refractions of light after it enters the lens. This leads to two problems: first, there is a significant loss of light passing through the lens; second, multiple reflections and refractions within the lens produce glare and ghosting.

[0005] Optical coating technology is an important branch of optical research. It involves coating the lens surface with a very thin, transparent film, effectively improving the aforementioned problems. After coating, the reflected light from the front and back surfaces of the film interferes with each other, thus canceling out the reflected light and increasing the intensity of transmitted light, giving the glass surface low reflection and high transmission properties. The simplest anti-reflection film is a single-layer film, which is a thin film with a low refractive index coated on the glass surface. If the optical thickness of the film is one-quarter of the wavelength of a certain light ray, the reflected light from the top and bottom surfaces of the film will undergo destructive interference. When a film with an appropriate refractive index is selected, the reflected light from the glass surface can be completely eliminated. Currently, the materials used to prepare single-layer films on glass are mainly magnesium fluoride or porous silica. Magnesium fluoride prepared by vacuum method requires heating the substrate, and magnesium fluoride prepared by evaporation has poor uniformity when coated over large areas, easily resulting in color differences. Silica prepared by sol-gel method has insufficient wear resistance, and dust on the film layer is difficult to remove. Most importantly, the light that needs to be antireflected is often not monochromatic, but has a certain bandwidth. A single-layer antireflection film can only completely antireflect monochromatic light of a certain wavelength. Therefore, it is difficult to achieve zero reflection and poor color neutrality when using a single-layer antireflection film.

[0006] In addition to reducing light reflection, researchers also hope to improve the corrosion resistance of products through coatings. However, existing coating materials generally have limited corrosion resistance, thus requiring further research and development.

[0007] Patent application CN111850480A discloses a coating process and the preparation of an optical lens, including a substrate and coating material. The coating material is a silicon-aluminum mixture, and the substrate is coated with four or more layers. The silicon-aluminum mixture has low refractive index, high hardness, good electrical insulation, and is resistant to friction, acids, alkalis, and corrosion. Aluminum has good chemical stability and a transparent aluminum oxide layer on its surface, exhibiting a flat and high reflectivity from the ultraviolet to the infrared region. However, the silicon-aluminum mixture obtained by simple mixing suffers from numerous problems during coating, including poor density, uniformity, and product reproducibility. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a wide-bandwidth ultra-low reflection coating process with a large incident angle, so as to solve the problems of uneven coating and high reflectivity of existing coated glass, and change the problems of glare and ghosting of optical thin films in lens lenses when used at large incident angles.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A wide-band ultra-low reflection coating process with a large incident angle involves first pretreating the surface of an aspherical glass substrate, and then sequentially depositing the following layers from bottom to top: silicon dioxide film, tantalum pentoxide film I, aluminum silicon oxide film I, tantalum pentoxide film II, aluminum silicon oxide film II, tantalum pentoxide film III, aluminum silicon oxide film III, tantalum pentoxide film IV, and yttrium-doped magnesium barium fluoride film. Post-treatment is then performed.

[0011] Preferably, the thicknesses of the silicon dioxide film, tantalum pentoxide film I, silicon aluminum oxide film I, tantalum pentoxide film II, silicon aluminum oxide film II, tantalum pentoxide film III, silicon aluminum oxide film III, tantalum pentoxide film IV, and yttrium-doped magnesium barium fluoride film are 18.39 nm, 14.71 nm, 61 nm, 12.56 nm, 48.46 nm, 42.64 nm, 12 nm, 43.17 nm, and 89.54 nm, respectively.

[0012] Preferably, the specific method of pretreatment is as follows: first, clean the substrate sequentially with acetone, distilled water and anhydrous ethanol, and then dry it at 75-85°C for 6-7 hours to obtain a clean substrate; then immerse the clean substrate in liquid nitrogen at -180--190°C for deep cryogenic treatment for 2-3 hours, and then restore it to room temperature under a nitrogen atmosphere; finally, perform low-temperature plasma treatment.

[0013] Further preferred process conditions for low-temperature plasma treatment are: working gas is argon, gas pressure is 50-60 Pa, discharge power is 150-200 W, and discharge treatment time is 8-10 minutes.

[0014] More preferably, during cleaning, the substrate is completely immersed in acetone, distilled water or anhydrous ethanol, and ultrasonically cleaned at 300-400W for 20-30 minutes. After removal, it is allowed to air dry naturally before proceeding to the next cleaning step.

[0015] Preferably, the silica film layer is formed by spin coating, and the coating material is prepared by the following method: first, tetraethyl orthosilicate is prepared into a tetraethyl orthosilicate solution with anhydrous ethanol at a concentration of 1-2 mol / L, stirred and heated to 85-95°C, and then 1-2 mol / L ammonia solution is added dropwise. After the addition is complete, the mixture is kept warm and stirred for 2-3 hours, and then naturally cooled to room temperature to obtain a premixed solution; finally, 0.2-0.3 times the volume of waterborne polyurethane resin is added to the premixed solution, and the mixture is stirred until homogeneous to obtain the final product; wherein, the solid content of the waterborne polyurethane resin is 10-15%, and it is purchased from Anhui Dawei Huatai New Material Technology Co., Ltd.

[0016] More preferably, the spin coating speed is 2000-3000 r / min.

[0017] Preferably, tantalum pentoxide film layer I, tantalum pentoxide film layer II, tantalum pentoxide film layer III, or tantalum pentoxide film layer IV is formed by vacuum evaporation. The coating material used is tantalum pentoxide with a particle size of 2-3 mm, and the vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 ~5×10 -3 Pa, pre-melting current 310~320mA, coating current 330~350mA, coating speed 0.5~0.8nm / s.

[0018] Preferably, silicon aluminum oxide film layer I, silicon aluminum oxide film layer II, or silicon aluminum oxide film layer is formed by vacuum evaporation.

[0019] III. The coating material used is silicon-aluminum oxide with a particle size of 2-3 mm, and the vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 ~5×10 -3 Pa, pre-melting current 150-160mA, coating current 170-180mA, coating speed 8-10nm / s.

[0020] More preferably, the silicon-aluminum oxide is prepared by the following method: alumina powder with a particle size of 5-10 μm is mixed evenly with silica powder with a particle size of 5-10 μm, sintered at 600-700°C for 8-10 hours, naturally cooled to room temperature, pulverized to a particle size of 5-10 μm, pressed at 500-700 MPa for 5-7 minutes, and then subjected to vacuum conditions at 1000-1000 MPa.

[0021] Sinter at 1100℃ for 8–10 hours, then pulverize to a particle size of 2–3 mm.

[0022] Preferably, the yttrium-doped magnesium barium fluoride film is formed by vacuum evaporation, and the coating material used is yttrium-doped magnesium barium fluoride. The vacuum evaporation process conditions are: vacuum degree 2×10 -3 ~3×10 -3 Pa, pre-melting current 90~100mA, coating current 110~120mA, coating speed 8~10nm / s.

[0023] More preferably, the yttrium-doped barium magnesium fluoride is prepared by the following method: first, barium chloride dihydrate, magnesium chloride hexahydrate, and yttrium nitrate hexahydrate are stirred and dissolved in a first portion of water to obtain solution A; potassium fluoride dihydrate is stirred and dissolved in a second portion of water to obtain solution B; while stirring, solution B is poured into solution A, stirred at 300 r / min for 30 minutes, heated to 60°C, kept at this temperature and stirred for 30 minutes, heating is stopped, allowed to stand for 60 minutes, centrifuged to collect the precipitate, washed with deionized water, dried, ground, and granulated to obtain yttrium-doped barium magnesium fluoride with a particle size of 2-3 mm.

[0024] More preferably, the ratio of barium chloride dihydrate, magnesium chloride hexahydrate, yttrium nitrate hexahydrate, water in the first part, potassium fluoride dihydrate, and water in the second part is 0.1 mol: 0.1 mol: 0.005 mol: 200 mL: 0.75 mol: 750 mL.

[0025] More preferably, the centrifugation process conditions are: centrifugation at 20000 r / min for 30 minutes.

[0026] Preferably, the post-treatment method is as follows: under a nitrogen atmosphere, first heat to 350-400℃ at 25℃ / min, hold for 30-40 minutes, then heat to 550-600℃ at 5℃ / min, hold for 30-40 minutes under magnetic field conditions, then cool to 400-450℃ at 15℃ / min, and allow to cool naturally to room temperature for low-temperature plasma treatment; wherein, the magnetic field conditions are: pulse frequency 800-900Hz, magnetic field strength 8-10T.

[0027] Further preferred process conditions for low-temperature plasma treatment are: working gas is argon, gas pressure is 120-150 Pa, discharge power is 50-70 W, and discharge treatment time is 3-5 minutes.

[0028] Meanwhile, the present invention also provides a lens, which is obtained by coating an aspherical glass substrate surface according to the aforementioned coating process.

[0029] Furthermore, this invention also aims to protect the application of the aforementioned lenses in lens manufacturing.

[0030] Preferably, the lens includes, but is not limited to: automotive lenses, action camera lenses, and mobile phone lenses.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention first pre-treats the surface of an aspherical glass substrate, then sequentially deposits a silicon dioxide film, a tantalum pentoxide film I, an aluminum silicon oxide film I, a tantalum pentoxide film II, an aluminum silicon oxide film II, a tantalum pentoxide film III, an aluminum silicon oxide film III, a tantalum pentoxide film IV, and a yttrium-doped magnesium barium fluoride film from bottom to top, followed by post-treatment. Lenses obtained by depositing the aspherical glass substrate surface according to this invention can be used in the manufacture of lenses for automotive, action cameras, and mobile phones. This invention solves the problems of uneven coating and high reflectivity in existing coated glass lenses, improves the glare and ghosting issues of optical thin films in lenses used at large incident angles, and exhibits excellent corrosion resistance.

[0033] This invention achieves low reflectivity and realizes high-definition images for both wide-angle and panoramic views through the synergistic effect of nine film layers: silicon dioxide film layer, tantalum pentoxide film layer I, silicon aluminum oxide film layer I, tantalum pentoxide film layer II, silicon aluminum oxide film layer II, tantalum pentoxide film layer III, silicon aluminum oxide film layer III, tantalum pentoxide film layer IV, and yttrium-doped magnesium barium fluoride film layer. At the same time, it improves the corrosion resistance of the product.

[0034] Besides the coordination between the various film layers, the pretreatment of the substrate and the post-treatment after coating are also crucial in this invention. The specific pretreatment method is as follows: first, the substrate is cleaned sequentially with acetone, distilled water, and anhydrous ethanol, and then dried to obtain a clean substrate; next, the clean substrate is immersed in liquid nitrogen for cryogenic treatment, and then restored to room temperature under a nitrogen atmosphere; finally, it undergoes low-temperature plasma treatment. This pretreatment alters the surface properties of the substrate, resulting in better adhesion of the silica film to the substrate surface, ensuring the optical performance and corrosion resistance of the product.

[0035] The specific post-treatment method is as follows: Under a nitrogen atmosphere, first heat to 350–400℃ at 25℃ / min, hold for 30–40 minutes, then heat to 550–600℃ at 5℃ / min, hold under a magnetic field for 30–40 minutes, then cool to 400–450℃ at 15℃ / min, allow to cool naturally to room temperature, and then perform low-temperature plasma treatment. Through the combination of staged heating and cooling, magnetic field treatment, and low-temperature plasma treatment, the film layer is further densified, the microstructure is optimized, and the product exhibits better optical and corrosion resistance properties. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the membrane structure of the present invention;

[0037] Figure 2 The reflectance diagram is for the lens prepared by the coating process in Example 1. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Unless otherwise specified, all products in this invention were purchased through market channels.

[0040] Example 1

[0041] A coating process involves first pretreating the surface of an aspherical glass substrate, and then sequentially coating from bottom to top to form a silicon dioxide film layer, a tantalum pentoxide film layer I, a silicon aluminum oxide film layer I, a tantalum pentoxide film layer II, a silicon aluminum oxide film layer II, a tantalum pentoxide film layer III, a silicon aluminum oxide film layer III, a tantalum pentoxide film layer IV, and a yttrium-doped magnesium barium fluoride film layer, followed by post-treatment.

[0042] The thicknesses of the silicon dioxide film, tantalum pentoxide film I, silicon aluminum oxide film I, tantalum pentoxide film II, silicon aluminum oxide film II, tantalum pentoxide film III, silicon aluminum oxide film III, tantalum pentoxide film IV, and yttrium-doped magnesium barium fluoride film are 18.39 nm, 14.71 nm, 61 nm, 12.56 nm, 48.46 nm, 42.64 nm, 12 nm, 43.17 nm, and 89.54 nm, respectively.

[0043] The specific pretreatment method is as follows: First, clean the substrate sequentially with acetone, distilled water, and anhydrous ethanol. After cleaning, dry the substrate at 75°C for 6 hours to obtain a clean substrate. Then, immerse the clean substrate in liquid nitrogen at -180°C for cryogenic treatment for 2 hours. After removal, allow it to return to room temperature under a nitrogen atmosphere. Finally, perform low-temperature plasma treatment. The process conditions for low-temperature plasma treatment are: working gas is argon, gas pressure is 50 Pa, discharge power is 150 W, and discharge treatment time is 8 minutes.

[0044] During cleaning, the substrate is completely immersed in acetone, distilled water or anhydrous ethanol, and ultrasonically cleaned for 20 minutes using 300W. After cleaning, it is removed and air-dried naturally before proceeding to the next cleaning step.

[0045] A silica film was formed using spin coating. The coating material was prepared as follows: Tetraethyl orthosilicate was first dissolved in anhydrous ethanol to prepare a 1 mol / L tetraethyl orthosilicate solution, which was then stirred and heated to 85°C. A 1 mol / L ammonia solution was then added dropwise. After the addition was complete, the mixture was kept at the same temperature and stirred for 2 hours, then allowed to cool naturally to room temperature to obtain a premix. Finally, 0.2 times the volume of waterborne polyurethane resin was added to the premix, and the mixture was stirred until homogeneous. The waterborne polyurethane resin had a solid content of 10% and was purchased from Anhui Dawei Huatai New Material Technology Co., Ltd. The spin coating speed was 2000 r / min.

[0046] Tantalum pentoxide film layer I, tantalum pentoxide film layer II, tantalum pentoxide film layer III, or tantalum pentoxide film layer IV is formed by vacuum evaporation. The coating material used is tantalum pentoxide with a particle size of 2 mm. The vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 Pa, pre-melting current 310mA, coating current 330mA, coating speed 0.5nm / s.

[0047] Silicon aluminum oxide film layer I, silicon aluminum oxide film layer II, or silicon aluminum oxide film layer III are formed by vacuum evaporation. The coating material used is silicon aluminum oxide with a particle size of 2 mm. The vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 Pa, pre-melting current 150mA, coating current 170mA, coating speed 8nm / s.

[0048] The silicon-aluminum oxide was prepared by the following method: first, alumina powder with a particle size of 5μm and silicon dioxide powder with a particle size of 5μm were mixed evenly, sintered at 600℃ for 8 hours, naturally cooled to room temperature, pulverized to a particle size of 5μm, pressed at 500MPa for 5 minutes, sintered at 1000℃ for 8 hours under vacuum, and pulverized to a particle size of 2mm.

[0049] Yttrium-doped magnesium barium fluoride film was formed by vacuum evaporation. The coating material used was yttrium-doped magnesium barium fluoride, and the vacuum evaporation process conditions were: vacuum degree 2 × 10⁻⁶.-3 Pa, pre-melting current 90mA, coating current 110mA, coating speed 8nm / s.

[0050] The yttrium-doped barium magnesium fluoride was prepared by the following method: 0.1 mol barium chloride dihydrate, 0.1 mol magnesium chloride hexahydrate, and 0.005 mol yttrium nitrate hexahydrate were first dissolved in 200 mL of water to obtain solution A; 0.75 mol potassium fluoride dihydrate was then dissolved in 750 mL of water to obtain solution B; solution B was poured into solution A while stirring, and the mixture was stirred at 300 r / min for 30 minutes. The mixture was then heated to 60°C and kept at that temperature for 30 minutes. Heating was stopped, and the mixture was allowed to stand for 60 minutes. The mixture was then centrifuged at 20000 r / min for 30 minutes. The precipitate was collected, washed with deionized water, dried, ground, and granulated to obtain yttrium-doped barium magnesium fluoride with a particle size of 2 mm.

[0051] The specific post-treatment method is as follows: Under a nitrogen atmosphere, first heat up to 350℃ at 25℃ / min and hold for 30 minutes, then heat up to 550℃ at 5℃ / min and hold for 30 minutes, then cool down to 400℃ at 15℃ / min and allow to cool naturally to room temperature. Low-temperature plasma treatment is then performed.

[0052] The process conditions for low-temperature plasma treatment are as follows: the working gas is argon, the gas pressure is 120 Pa, the discharge power is 50 W, and the discharge treatment time is 3 minutes.

[0053] Example 2

[0054] A wide-band ultra-low reflection coating process with a large incident angle involves first pretreating the surface of an aspherical glass substrate, then sequentially depositing the following layers from bottom to top: silicon dioxide, tantalum pentoxide (layer I), aluminum silicon oxide (layer I), tantalum pentoxide (layer II), aluminum silicon oxide (layer II), tantalum pentoxide (layer III), aluminum silicon oxide (layer III), tantalum pentoxide (layer IV), and yttrium-doped magnesium barium fluoride (layer IV). Post-treatment is then performed. A schematic diagram of the film structure is shown below. Figure 1 .

[0055] The thicknesses of the silicon dioxide film, tantalum pentoxide film I, silicon aluminum oxide film I, tantalum pentoxide film II, silicon aluminum oxide film II, tantalum pentoxide film III, silicon aluminum oxide film III, tantalum pentoxide film IV, and yttrium-doped magnesium barium fluoride film are 18.39 nm, 14.71 nm, 61 nm, 12.56 nm, 48.46 nm, 42.64 nm, 12 nm, 43.17 nm, and 89.54 nm, respectively.

[0056] The specific pretreatment method is as follows: First, clean the substrate sequentially with acetone, distilled water, and anhydrous ethanol. After cleaning, dry the substrate at 75°C for 6 hours to obtain a clean substrate. Then, immerse the clean substrate in liquid nitrogen at -180°C for cryogenic treatment for 2 hours. After removal, allow it to return to room temperature under a nitrogen atmosphere. Finally, perform low-temperature plasma treatment. The process conditions for low-temperature plasma treatment are: working gas is argon, gas pressure is 50 Pa, discharge power is 150 W, and discharge treatment time is 8 minutes.

[0057] During cleaning, the substrate is completely immersed in acetone, distilled water or anhydrous ethanol, and ultrasonically cleaned for 20 minutes using 300W. After cleaning, it is removed and air-dried naturally before proceeding to the next cleaning step.

[0058] A silica film was formed using spin coating. The coating material was prepared as follows: Tetraethyl orthosilicate was first dissolved in anhydrous ethanol to prepare a 1 mol / L tetraethyl orthosilicate solution, which was then stirred and heated to 85°C. A 1 mol / L ammonia solution was then added dropwise. After the addition was complete, the mixture was kept at the same temperature and stirred for 2 hours, then allowed to cool naturally to room temperature to obtain a premix. Finally, 0.2 times the volume of waterborne polyurethane resin was added to the premix, and the mixture was stirred until homogeneous. The waterborne polyurethane resin had a solid content of 10% and was purchased from Anhui Dawei Huatai New Material Technology Co., Ltd. The spin coating speed was 2000 r / min.

[0059] Tantalum pentoxide film layer I, tantalum pentoxide film layer II, tantalum pentoxide film layer III, or tantalum pentoxide film layer IV is formed by vacuum evaporation. The coating material used is tantalum pentoxide with a particle size of 2 mm. The vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 Pa, pre-melting current 310mA, coating current 330mA, coating speed 0.5nm / s.

[0060] Silicon aluminum oxide film layer I, silicon aluminum oxide film layer II, or silicon aluminum oxide film layer III are formed by vacuum evaporation. The coating material used is silicon aluminum oxide with a particle size of 2 mm. The vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 Pa, pre-melting current 150mA, coating current 170mA, coating speed 8nm / s.

[0061] The silicon-aluminum oxide was prepared by the following method: first, alumina powder with a particle size of 5μm and silicon dioxide powder with a particle size of 5μm were mixed evenly, sintered at 600℃ for 8 hours, naturally cooled to room temperature, pulverized to a particle size of 5μm, pressed at 500MPa for 5 minutes, sintered at 1000℃ for 8 hours under vacuum, and pulverized to a particle size of 2mm.

[0062] Yttrium-doped magnesium barium fluoride film was formed by vacuum evaporation. The coating material used was yttrium-doped magnesium barium fluoride, and the vacuum evaporation process conditions were: vacuum degree 2 × 10⁻⁶.-3 Pa, pre-melting current 90mA, coating current 110mA, coating speed 8nm / s.

[0063] The yttrium-doped barium magnesium fluoride was prepared by the following method: 0.1 mol barium chloride dihydrate, 0.1 mol magnesium chloride hexahydrate, and 0.005 mol yttrium nitrate hexahydrate were first dissolved in 200 mL of water to obtain solution A; 0.75 mol potassium fluoride dihydrate was then dissolved in 750 mL of water to obtain solution B; solution B was poured into solution A while stirring, and the mixture was stirred at 300 r / min for 30 minutes. The mixture was then heated to 60°C and kept at that temperature for 30 minutes. Heating was stopped, and the mixture was allowed to stand for 60 minutes. The mixture was then centrifuged at 20000 r / min for 30 minutes. The precipitate was collected, washed with deionized water, dried, ground, and granulated to obtain yttrium-doped barium magnesium fluoride with a particle size of 2 mm.

[0064] The specific post-treatment method is as follows: Under a nitrogen atmosphere, first heat up to 350℃ at 25℃ / min and hold for 30 minutes, then heat up to 550℃ at 5℃ / min and hold for 30 minutes under magnetic field conditions, then cool down to 400℃ at 15℃ / min and allow to cool naturally to room temperature for low-temperature plasma treatment; the magnetic field conditions are: pulse frequency 800Hz and magnetic field strength 8T.

[0065] The process conditions for low-temperature plasma treatment are as follows: the working gas is argon, the gas pressure is 120 Pa, the discharge power is 50 W, and the discharge treatment time is 3 minutes.

[0066] Example 3

[0067] A wide-band ultra-low reflection coating process with a large incident angle involves first pretreating the surface of an aspherical glass substrate, then sequentially depositing the following layers from bottom to top: silicon dioxide, tantalum pentoxide (layer I), aluminum silicon oxide (layer I), tantalum pentoxide (layer II), aluminum silicon oxide (layer II), tantalum pentoxide (layer III), aluminum silicon oxide (layer III), tantalum pentoxide (layer IV), and yttrium-doped magnesium barium fluoride (layer IV). Post-treatment is then performed. A schematic diagram of the film structure is shown below. Figure 1 .

[0068] The thicknesses of the silicon dioxide film, tantalum pentoxide film I, silicon aluminum oxide film I, tantalum pentoxide film II, silicon aluminum oxide film II, tantalum pentoxide film III, silicon aluminum oxide film III, tantalum pentoxide film IV, and yttrium-doped magnesium barium fluoride film are 18.39 nm, 14.71 nm, 61 nm, 12.56 nm, 48.46 nm, 42.64 nm, 12 nm, 43.17 nm, and 89.54 nm, respectively.

[0069] The specific pretreatment method is as follows: First, clean the substrate sequentially with acetone, distilled water, and anhydrous ethanol. After cleaning, dry the substrate at 85°C for 7 hours to obtain a clean substrate. Then, immerse the clean substrate in liquid nitrogen at -190°C for cryogenic treatment for 3 hours. After removal, allow it to return to room temperature under a nitrogen atmosphere. Finally, perform low-temperature plasma treatment. The process conditions for low-temperature plasma treatment are: working gas is argon, gas pressure is 60 Pa, discharge power is 200 W, and discharge treatment time is 10 minutes.

[0070] During cleaning, the substrate is completely immersed in acetone, distilled water or anhydrous ethanol, and ultrasonically cleaned for 30 minutes at 400W. After cleaning, it is removed and air-dried naturally before proceeding to the next cleaning step.

[0071] A silica film was formed using spin coating. The coating material was prepared as follows: Tetraethyl orthosilicate was first dissolved in anhydrous ethanol to prepare a 2 mol / L tetraethyl orthosilicate solution, which was then stirred and heated to 95°C. A 2 mol / L ammonia solution was then added dropwise. After the addition was complete, the mixture was kept at the same temperature and stirred for 3 hours, then allowed to cool naturally to room temperature to obtain a premix. Finally, 0.3 times the volume of waterborne polyurethane resin was added to the premix, and the mixture was stirred until homogeneous. The waterborne polyurethane resin had a solid content of 15% and was purchased from Anhui Dawei Huatai New Material Technology Co., Ltd. The spin coating speed was 3000 r / min.

[0072] Tantalum pentoxide film layer I, tantalum pentoxide film layer II, tantalum pentoxide film layer III, or tantalum pentoxide film layer IV is formed by vacuum evaporation. The coating material used is tantalum pentoxide with a particle size of 3 mm. The vacuum evaporation process conditions are: vacuum degree 5 × 10⁻⁶. -3 Pa, pre-melting current 320mA, coating current 350mA, coating speed 0.8nm / s.

[0073] Silicon-aluminum oxide film layer I, silicon-aluminum oxide film layer II, or silicon-aluminum oxide film layer III is formed by vacuum evaporation. The coating material used is silicon-aluminum oxide with a particle size of 3 mm. The vacuum evaporation process conditions are: vacuum degree 5 × 10⁻⁶. -3 Pa, pre-melting current 160mA, coating current 180mA, coating speed 10nm / s.

[0074] The silicon-aluminum oxide was prepared by the following method: alumina powder with a particle size of 10 μm was mixed evenly with silicon dioxide powder with a particle size of 10 μm, sintered at 700℃ for 10 hours, naturally cooled to room temperature, pulverized to a particle size of 10 μm, pressed at 700 MPa for 7 minutes, sintered at 1100℃ for 10 hours under vacuum, and pulverized to a particle size of 3 mm.

[0075] Yttrium-doped magnesium barium fluoride film was formed by vacuum evaporation. The coating material used was yttrium-doped magnesium barium fluoride, and the vacuum evaporation process conditions were: vacuum degree 3 × 10⁻⁶. -3 Pa, pre-melting current 100mA, coating current 120mA, coating speed 10nm / s.

[0076] The yttrium-doped barium magnesium fluoride was prepared by the following method: 0.1 mol barium chloride dihydrate, 0.1 mol magnesium chloride hexahydrate, and 0.005 mol yttrium nitrate hexahydrate were first dissolved in 200 mL of water to obtain solution A; 0.75 mol potassium fluoride dihydrate was then dissolved in 750 mL of water to obtain solution B; solution B was poured into solution A while stirring, and the mixture was stirred at 300 r / min for 30 minutes. The mixture was then heated to 60°C and kept at that temperature for 30 minutes. Heating was stopped, and the mixture was allowed to stand for 60 minutes. The mixture was then centrifuged at 20000 r / min for 30 minutes. The precipitate was collected, washed with deionized water, dried, ground, and granulated to obtain yttrium-doped barium magnesium fluoride with a particle size of 3 mm.

[0077] The specific post-treatment method is as follows: Under a nitrogen atmosphere, first heat up to 400℃ at 25℃ / min and hold for 40 minutes, then heat up to 600℃ at 5℃ / min and hold for 40 minutes under magnetic field conditions, then cool down to 450℃ at 15℃ / min and allow to cool naturally to room temperature for low-temperature plasma treatment; the magnetic field conditions are: pulse frequency 900Hz and magnetic field strength 10T.

[0078] The process conditions for low-temperature plasma treatment are as follows: the working gas is argon, the gas pressure is 150 Pa, the discharge power is 70 W, and the discharge treatment time is 5 minutes.

[0079] Example 4

[0080] A wide-band ultra-low reflection coating process with a large incident angle involves first pretreating the surface of an aspherical glass substrate, then sequentially depositing the following layers from bottom to top: silicon dioxide, tantalum pentoxide (layer I), aluminum silicon oxide (layer I), tantalum pentoxide (layer II), aluminum silicon oxide (layer II), tantalum pentoxide (layer III), aluminum silicon oxide (layer III), tantalum pentoxide (layer IV), and yttrium-doped magnesium barium fluoride (layer IV). Post-treatment is then performed. A schematic diagram of the film structure is shown below. Figure 1 .

[0081] The thicknesses of the silicon dioxide film, tantalum pentoxide film I, silicon aluminum oxide film I, tantalum pentoxide film II, silicon aluminum oxide film II, tantalum pentoxide film III, silicon aluminum oxide film III, tantalum pentoxide film IV, and yttrium-doped magnesium barium fluoride film are 18.39 nm, 14.71 nm, 61 nm, 12.56 nm, 48.46 nm, 42.64 nm, 12 nm, 43.17 nm, and 89.54 nm, respectively.

[0082] The specific pretreatment method is as follows: First, clean the substrate sequentially with acetone, distilled water, and anhydrous ethanol. After cleaning, dry the substrate at 80℃ for 6.5 hours to obtain a clean substrate. Then, immerse the clean substrate in liquid nitrogen at -185℃ for cryogenic treatment for 2.5 hours. After removal, allow it to return to room temperature under a nitrogen atmosphere. Finally, perform low-temperature plasma treatment. The process conditions for low-temperature plasma treatment are: working gas is argon, gas pressure is 55 Pa, discharge power is 180 W, and discharge treatment time is 9 minutes.

[0083] During cleaning, the substrate is completely immersed in acetone, distilled water or anhydrous ethanol and cleaned with 400W ultrasonic vibration for 25 minutes. After cleaning, it is removed and air-dried naturally before proceeding to the next cleaning step.

[0084] A silica film was formed using spin coating. The coating material was prepared as follows: Tetraethyl orthosilicate was first dissolved in anhydrous ethanol to prepare a 1.5 mol / L tetraethyl orthosilicate solution, which was then stirred and heated to 90°C. A 1.5 mol / L ammonia solution was then added dropwise. After the addition was complete, the mixture was kept at this temperature and stirred for 2.5 hours, then allowed to cool naturally to room temperature to obtain a premix. Finally, 0.25 times the volume of waterborne polyurethane resin was added to the premix, and the mixture was stirred until homogeneous. The waterborne polyurethane resin had a solid content of 12% and was purchased from Anhui Dawei Huatai New Material Technology Co., Ltd. The spin coating speed was 3000 r / min.

[0085] Tantalum pentoxide film layer I, tantalum pentoxide film layer II, tantalum pentoxide film layer III, or tantalum pentoxide film layer IV is formed by vacuum evaporation. The coating material used is tantalum pentoxide with a particle size of 3 mm. The vacuum evaporation process conditions are: vacuum degree 5 × 10⁻⁶. -3 Pa, pre-melting current 320mA, coating current 340mA, coating speed 0.6nm / s.

[0086] Silicon aluminum oxide film layer I, silicon aluminum oxide film layer II, or silicon aluminum oxide film layer III are formed by vacuum evaporation. The coating material used is silicon aluminum oxide with a particle size of 2 mm. The vacuum evaporation process conditions are: vacuum degree 5 × 10⁻⁶. -3 Pa, pre-melting current 150mA, coating current 170mA, coating speed 9nm / s.

[0087] The silicon-aluminum oxide was prepared by the following method: alumina powder with a particle size of 10 μm was mixed evenly with silicon dioxide powder with a particle size of 10 μm, sintered at 650°C for 9 hours, naturally cooled to room temperature, pulverized to a particle size of 10 μm, pressed at 600 MPa for 6 minutes, sintered at 1050°C for 9 hours under vacuum, and pulverized to a particle size of 2 mm.

[0088] Yttrium-doped magnesium barium fluoride film was formed by vacuum evaporation. The coating material used was yttrium-doped magnesium barium fluoride, and the vacuum evaporation process conditions were: vacuum degree 3 × 10⁻⁶. -3 Pa, pre-melting current 90mA, coating current 110mA, coating speed 9nm / s.

[0089] The yttrium-doped barium magnesium fluoride was prepared by the following method: 0.1 mol barium chloride dihydrate, 0.1 mol magnesium chloride hexahydrate, and 0.005 mol yttrium nitrate hexahydrate were first dissolved in 200 mL of water to obtain solution A; 0.75 mol potassium fluoride dihydrate was then dissolved in 750 mL of water to obtain solution B; solution B was poured into solution A while stirring, and the mixture was stirred at 300 r / min for 30 minutes. The mixture was then heated to 60°C and kept at that temperature for 30 minutes. Heating was stopped, and the mixture was allowed to stand for 60 minutes. The mixture was then centrifuged at 20000 r / min for 30 minutes. The precipitate was collected, washed with deionized water, dried, ground, and granulated to obtain yttrium-doped barium magnesium fluoride with a particle size of 2 mm.

[0090] The specific post-treatment method is as follows: Under a nitrogen atmosphere, first heat up to 380℃ at 25℃ / min and hold for 35 minutes, then heat up to 580℃ at 5℃ / min and hold for 35 minutes under magnetic field conditions, then cool down to 420℃ at 15℃ / min and allow to cool naturally to room temperature for low-temperature plasma treatment; the magnetic field conditions are: pulse frequency 900Hz and magnetic field strength 9T.

[0091] The process conditions for low-temperature plasma treatment are as follows: the working gas is argon, the gas pressure is 140 Pa, the discharge power is 60 W, and the discharge treatment time is 4 minutes.

[0092] Comparative Example

[0093] A coating process involves first pretreating the surface of an aspherical glass substrate, and then sequentially coating from bottom to top to form a silicon dioxide film layer, a tantalum pentoxide film layer I, a silicon aluminum oxide film layer I, a tantalum pentoxide film layer II, a silicon aluminum oxide film layer II, a tantalum pentoxide film layer III, a silicon aluminum oxide film layer III, a tantalum pentoxide film layer IV, and a magnesium fluoride film layer, followed by post-treatment.

[0094] The thicknesses of the silicon dioxide film, tantalum pentoxide film I, silicon aluminum oxide film I, tantalum pentoxide film II, silicon aluminum oxide film II, tantalum pentoxide film III, silicon aluminum oxide film III, tantalum pentoxide film IV, and yttrium-doped magnesium barium fluoride film are 18.39 nm, 14.71 nm, 61 nm, 12.56 nm, 48.46 nm, 42.64 nm, 12 nm, 43.17 nm, and 89.54 nm, respectively.

[0095] The specific pretreatment method is as follows: First, clean the substrate sequentially with acetone, distilled water, and anhydrous ethanol. After cleaning, dry the substrate at 75°C for 6 hours to obtain a clean substrate. Then, immerse the clean substrate in liquid nitrogen at -180°C for cryogenic treatment for 2 hours. After removal, allow it to return to room temperature under a nitrogen atmosphere. Finally, perform low-temperature plasma treatment. The process conditions for low-temperature plasma treatment are: working gas is argon, gas pressure is 50 Pa, discharge power is 150 W, and discharge treatment time is 8 minutes.

[0096] During cleaning, the substrate is completely immersed in acetone, distilled water or anhydrous ethanol, and ultrasonically cleaned for 20 minutes using 300W. After cleaning, it is removed and air-dried naturally before proceeding to the next cleaning step.

[0097] A silica film was formed using spin coating. The coating material was prepared as follows: Tetraethyl orthosilicate was first dissolved in anhydrous ethanol to prepare a 1 mol / L tetraethyl orthosilicate solution, which was then stirred and heated to 85°C. A 1 mol / L ammonia solution was then added dropwise. After the addition was complete, the mixture was kept at the same temperature and stirred for 2 hours, then allowed to cool naturally to room temperature to obtain a premix. Finally, 0.2 times the volume of waterborne polyurethane resin was added to the premix, and the mixture was stirred until homogeneous. The waterborne polyurethane resin had a solid content of 10% and was purchased from Anhui Dawei Huatai New Material Technology Co., Ltd. The spin coating speed was 2000 r / min.

[0098] Tantalum pentoxide film layer I, tantalum pentoxide film layer II, tantalum pentoxide film layer III, or tantalum pentoxide film layer IV is formed by vacuum evaporation. The coating material used is tantalum pentoxide with a particle size of 2 mm. The vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 Pa, pre-melting current 310mA, coating current 330mA, coating speed 0.5nm / s.

[0099] Silicon aluminum oxide film layer I, silicon aluminum oxide film layer II, or silicon aluminum oxide film layer III are formed by vacuum evaporation. The coating material used is silicon aluminum oxide with a particle size of 2 mm. The vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 Pa, pre-melting current 150mA, coating current 170mA, coating speed 8nm / s.

[0100] The silicon-aluminum oxide was prepared by the following method: first, alumina powder with a particle size of 5μm and silicon dioxide powder with a particle size of 5μm were mixed evenly, sintered at 600℃ for 8 hours, naturally cooled to room temperature, pulverized to a particle size of 5μm, pressed at 500MPa for 5 minutes, sintered at 1000℃ for 8 hours under vacuum, and pulverized to a particle size of 2mm.

[0101] A magnesium fluoride film was formed by vacuum evaporation. The coating material used was magnesium fluoride with a particle size of 2 mm. The vacuum evaporation process conditions were: vacuum degree 2 × 10⁻⁶.-3 Pa, pre-melting current 90mA, coating current 110mA, coating speed 8nm / s.

[0102] The specific post-treatment method is as follows: Under a nitrogen atmosphere, first heat up to 350℃ at 25℃ / min and hold for 30 minutes, then heat up to 550℃ at 5℃ / min and hold for 30 minutes under magnetic field conditions, then cool down to 400℃ at 15℃ / min and allow to cool naturally to room temperature for low-temperature plasma treatment; the magnetic field conditions are: pulse frequency 800Hz and magnetic field strength 8T.

[0103] The process conditions for low-temperature plasma treatment are as follows: the working gas is argon, the gas pressure is 120 Pa, the discharge power is 50 W, and the discharge treatment time is 3 minutes.

[0104] Test case

[0105] For ease of comparison, the substrate of the present invention uses the same glass with a size of 10cm×10cm×3mm, and is processed by the coating process of Examples 1 to 4 or Comparative Example 1 to obtain the corresponding lenses.

[0106] The reflectivity of the lens was tested using a reflectivity meter (Guangzhou Huruiming Instrument Co., Ltd., 723TGR). The measurement wavelength range was 400nm to 700nm, and data from 425nm to 675nm were collected to record the highest reflectivity. The results are shown below. Figure 1 See Table 1.

[0107] Table 1. Comparison of Reflectivity

[0108] Example 2 0.10 Example 3 0.10 Example 4 0.08 Comparative Example 0.53

[0109] Depend on Figure 1 As shown in Table 1, the lenses obtained in Examples 1-4 have low reflectivity. The post-processing step in Example 1, which omits the magnetic field treatment, resulted in slightly higher reflectivity compared to Examples 2-4, indicating that post-processing affects product reflectivity. In the comparative example, replacing the yttrium-doped magnesium barium fluoride film with a magnesium fluoride film significantly increased reflectivity, demonstrating the synergistic effect of the film structure in this invention, reducing product reflectivity.

[0110] Under conditions of 25℃ and 60% RH, the aforementioned lenses were completely immersed in a sodium chloride aqueous solution (obtained by dissolving 200g of sodium chloride in 1L of distilled water) for 7 days, and then dried. The haze values ​​before and after treatment were measured using an integrating sphere haze meter (Jinan Detian Electromechanical Technology Co., Ltd., DT-WGW), and the haze difference was calculated. The results are shown in Table 2.

[0111] Table 2. Haze Difference

[0112] Example 1 0.11 Example 2 0.02 Example 3 0.02 Example 4 0.01 Comparative Example 0.97

[0113] Table 2 shows that the lenses obtained in Examples 1-4 exhibited small haze differences before and after treatment with sodium chloride solution, indicating good corrosion resistance. In Example 1, the post-treatment step omitted the magnetic field treatment, resulting in a slightly higher haze difference compared to Examples 2-4. In the comparative example, replacing the yttrium-doped magnesium barium fluoride film with a magnesium fluoride film significantly increased the haze difference and significantly worsened corrosion resistance, demonstrating the synergistic effect of the film structure in this invention, which improves the corrosion resistance of the product.

[0114] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of individual raw materials in the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A broadband ultra-low reflection coating process with a large incident angle, characterized in that, First, the surface of the aspherical glass substrate is pretreated. Then, from bottom to top, the following films are deposited sequentially: silicon dioxide film layer, tantalum pentoxide film layer I, aluminum silicon oxide film layer I, tantalum pentoxide film layer II, aluminum silicon oxide film layer II, tantalum pentoxide film layer III, aluminum silicon oxide film layer III, tantalum pentoxide film layer IV, and yttrium-doped magnesium barium fluoride film layer. Post-treatment is then performed. The specific pretreatment method is as follows: First, clean the substrate sequentially with acetone, distilled water and anhydrous ethanol. After cleaning, dry it at 75-85℃ for 6-7 hours to obtain a clean substrate. Then, immerse the clean substrate in liquid nitrogen at -190--180℃ for deep cryogenic treatment for 2-3 hours. After taking it out, restore it to room temperature under a nitrogen atmosphere. Finally, perform low-temperature plasma treatment. The specific post-treatment method is as follows: Under a nitrogen atmosphere, first raise the temperature to 350-400℃ at 25℃ / min, hold for 30-40 minutes, then raise the temperature to 550-600℃ at 5℃ / min, hold for 30-40 minutes under a magnetic field, then lower the temperature to 400-450℃ at 15℃ / min, and allow it to cool naturally to room temperature. Low-temperature plasma treatment is then performed. The magnetic field conditions are: pulse frequency 800-900Hz, magnetic field strength 8-10T. The thicknesses of the silicon dioxide film, tantalum pentoxide film I, silicon aluminum oxide film I, tantalum pentoxide film II, silicon aluminum oxide film II, tantalum pentoxide film III, silicon aluminum oxide film III, tantalum pentoxide film IV, and yttrium-doped magnesium barium fluoride film are 18.39 nm, 14.71 nm, 61 nm, 12.56 nm, 48.46 nm, 42.64 nm, 12 nm, 43.17 nm, and 89.54 nm, respectively.

2. The coating process according to claim 1, characterized in that, The silica film layer is formed by spin coating. The coating material is prepared by the following method: First, tetraethyl orthosilicate is prepared into a 1-2 mol / L tetraethyl orthosilicate solution using anhydrous ethanol. The solution is stirred and heated to 85-95°C. Then, a 1-2 mol / L ammonia solution is added dropwise. After the addition is complete, the solution is kept warm and stirred for 2-3 hours. The solution is then naturally cooled to room temperature to obtain a premixed solution. Finally, 0.2-0.3 times the volume of waterborne polyurethane resin is added to the premixed solution and stirred until homogeneous. The solid content of the waterborne polyurethane resin is 10-15%.

3. The coating process according to claim 1, characterized in that, Tantalum pentoxide film layer I, tantalum pentoxide film layer II, tantalum pentoxide film layer III, or tantalum pentoxide film layer IV is formed by vacuum evaporation. The coating material used is tantalum pentoxide with a particle size of 2-3 mm. The vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 ~5×10 -3 Pa, pre-melting current 310~320mA, coating current 330~350mA, coating speed 0.5~0.8nm / s.

4. The coating process according to claim 1, characterized in that, Silicon aluminum oxide film layer I, silicon aluminum oxide film layer II, or silicon aluminum oxide film layer III are formed by vacuum evaporation. The coating material used is silicon aluminum oxide with a particle size of 2-3 mm. The vacuum evaporation process conditions are: vacuum degree 4 × 10⁻⁶. -3 ~5×10 -3 Pa, pre-melting current 150-160mA, coating current 170-180mA, coating speed 8-10nm / s.

5. The coating process according to claim 1, characterized in that, Yttrium-doped magnesium barium fluoride film was formed by vacuum evaporation. The coating material used was yttrium-doped magnesium barium fluoride, and the vacuum evaporation process conditions were: vacuum degree 2 × 10⁻⁶. -3 ~3×10 -3 Pa, pre-melting current 90~100mA, coating current 110~120mA, coating speed 8~10nm / s.

6. A lens, characterized in that, It is obtained by coating the surface of an aspherical glass substrate according to the coating process described in any one of claims 1 to 5.

7. The use of the lens according to claim 6 in lens manufacturing.

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