High-wear-resistance anti-dazzle antireflection optical film and preparation method thereof

Abstract

The invention relates to the technical field of optical films, in particular to a high-wear-resistance anti-dazzle antireflection optical film and a preparation method thereof. The anti-dazzle wear-resistant optical film comprises an optical substrate, a bonding layer, an anti-reflection functional layer and a composite anti-dazzle wear-resistant layer, and the composite anti-dazzle wear-resistant layer comprises the following raw materials: nanometer aluminum oxide particles, nanometer silicon dioxide particles, a silane coupling agent and a hydrolysis catalyst. According to the invention, the hafnium oxide-aluminum oxide mixture and the silicon dioxide are adopted to alternately construct a gradient refractive index film system, so that the interface stress is essentially reduced; meanwhile, a composite anti-dazzle wear-resistant layer composed of boehmite nanorods, nano silicon dioxide and a silane coupling agent is designed, so that the film obtains excellent mechanical durability while achieving wide-spectrum ultra-low reflection and effective anti-dazzle, the industrial problems that a film layer is easy to peel off and an anti-dazzle microstructure is easy to wear are fundamentally solved, and the anti-dazzle wear-resistant film has good application prospects. And the high-performance and long-service-life optical thin film suitable for severe environments and high-frequency interaction scenes is successfully prepared.

Description

Technical Field

[0001] This invention relates to the field of optical thin film technology, and more specifically, to a highly wear-resistant, anti-glare, and anti-reflective optical thin film and its preparation method. Background Technology

[0002] Optical thin films refer to thin-layer systems deposited on the surface of optical components through physicochemical methods. Based on the principle of light interference, they regulate the transmission, reflection, and scattering behavior of light, and are key components for achieving specific optical functions such as anti-reflection, anti-glare, beam splitting, and anti-glare. Among them, optical thin films that combine broad-spectrum low reflectivity, effective anti-glare, and high surface mechanical abrasion resistance are the core functional layers in various display panels, instrument windows, lenses, and precision optical sensors, directly determining the imaging clarity, visual comfort, and long-term performance stability of the optical system.

[0003] While pursuing excellent optical performance across a wide angle and wavelength, existing technologies face severe challenges in terms of mechanical durability: On the one hand, multilayer antireflective coatings that rely on precise thickness control have physical interfaces between their layers. These interfaces are not only weak points in stress, affecting the bonding strength between the film and the substrate and between the film layers, but they can also become the starting point for crack initiation and propagation under mechanical friction or impact, leading to irreversible degradation of optical performance.

[0004] On the other hand, the anti-glare functional layer based on surface morphology control generally lacks sufficient mechanical strength in its micro-nano structure. Under conditions such as daily cleaning, touching, or sand and dust friction, the surface protrusion structure is easily worn down, causing the anti-glare (AG) effect to gradually decline or even be completely lost.

[0005] In summary, existing anti-glare and anti-reflection optical thin film technologies generally suffer from insufficient mechanical reliability of the film layer and poor mechanical durability of optical performance when facing high-abrasion-resistant operating environments. This limits their application in fields requiring long-life and high-reliability optical components, such as outdoor equipment, industrial inspection, and frequent interactive interfaces. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing anti-glare and anti-reflection optical thin film technologies in terms of the bonding strength between film layers and the mechanical durability of the surface structure.

[0007] The purpose of this invention is to provide a high wear-resistant, anti-glare, and anti-reflection optical thin film and its preparation method. Through a series of precise and continuous process steps, the reliable preparation of the multilayer functional film system is achieved, thereby synergistically solving the deficiencies in the film layer bonding strength and surface structure mechanical durability.

[0008] To achieve the above objectives, one objective of this invention is to provide a highly wear-resistant, anti-glare, and anti-reflective optical film. The optical film, from bottom to top, comprises: an optical substrate, a bonding layer, an anti-reflective functional layer, and a composite anti-glare and wear-resistant layer. The composite anti-glare and wear-resistant layer comprises the following raw materials in the following mass percentages: The composition consists of 40-60% nano-alumina particles, 35-55% nano-silica particles, 0.5-2.5% silane coupling agent, and the remainder is a hydrolysis catalyst.

[0009] As a further improvement to this technical solution, the anti-reflection functional layer is composed of alternating layers of high-refractive-index material and low-refractive-index material from the self-bonding layer outwards. The raw material for the high refractive index material layer is a mixture of hafnium dioxide and aluminum oxide, wherein the molar ratio of hafnium dioxide to aluminum oxide is 7:3; The raw material for the low refractive index material layer is silicon dioxide.

[0010] As a further improvement to this technical solution, the total physical thickness of the anti-reflection functional layer is 300-600nm.

[0011] A second objective of this invention is to provide a method for preparing the aforementioned high wear-resistant, anti-glare, and anti-reflection optical thin film, comprising the following steps: Step S1: Weigh the raw materials according to the mass ratio; Then, optical substrate pretreatment is performed, and bonding layer deposition is carried out on the optical substrate; Step S2: Using a process combining multi-target co-sputtering and sequential deposition, a multilayer film system with alternating high-refractive-index material layers and low-refractive-index material layers is constructed on the bonding layer to serve as an anti-reflection functional layer in the optical thin film. Step S3: In a mixed solvent of anhydrous ethanol and deionized water, nano-alumina, nano-silica particles, and silane coupling agent are added sequentially, followed by the addition of a hydrolysis catalyst, and the mixture is mechanically stirred to form a composite sol. The coating substrate obtained in step S2 is placed on a spin coater, and a composite sol is coated by spin coating. Then, a wet gel film is obtained after pre-curing treatment. Step S4: Align the template with the biomimetic moth eye array structure with the wet gel membrane, place it in the nanoimprint device, apply a pressure of 0.4-0.6 MPa and maintain it for 2-4 minutes to allow the gel membrane to completely fill the template cavity; Optical films are obtained and preserved through structural curing and heat treatment.

[0012] As a further improvement to this technical solution, in step S2, High refractive index material layer deposition: Hf target and Al target co-sputtering is used. By independently controlling the sputtering power of the two targets, a mixture with a molar ratio of 7:3 of hafnium dioxide and aluminum oxide is deposited. Deposition of low refractive index material layer: With Al target off, only Si target is used for reactive sputtering under the same argon-oxygen atmosphere to deposit a pure silicon dioxide layer for 25 min.

[0013] As a further improvement to this technical solution, the deposition process of the above-mentioned high and low refractive index material layers is repeated alternately for 4-5 cycles; During the deposition of each high- and low-refractive-index material layer, the power of the Hf target and the Al target is linearly adjusted during the 1-3 minute period at the beginning and end, so that the chemical composition and refractive index between layers can achieve a quasi-continuous gradual change.

[0014] As a further improvement to this technical solution, in step S3, the mixture is continuously mechanically stirred and refluxed in a 60°C water bath for 4-8 hours, then aged for 24 hours, and filtered using a 0.22μm filter membrane to obtain a uniform and stable composite sol.

[0015] As a further improvement to this technical solution, in step S3, the pre-curing process involves placing the product on an 80°C hot plate for 10 minutes, then transferring it to an oven and keeping it at 150°C for 1 hour to form a smooth wet gel film.

[0016] As a further improvement to this technical solution, in step S4, the structural curing process is to use ultraviolet light irradiation or heat curing under pressure to completely cure the gel film into a hard ceramic layer. After cooling to room temperature, release the pressure and gently demold to replicate a high-fidelity anti-glare micro-nano structure on the surface of the composite anti-glare and wear-resistant layer.

[0017] As a further improvement to this technical solution, in step S4, the heat treatment involves placing the demolded product into a muffle furnace and annealing it in an air atmosphere at 400-600℃ for 1-3 hours.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: In this high wear-resistant, anti-glare, and anti-reflection optical thin film and its preparation method, a gradient refractive index film system is constructed by alternating hafnium dioxide-alumina mixture and silicon dioxide in a specific molar ratio, which essentially reduces interfacial stress. At the same time, a composite anti-glare and wear-resistant layer composed of boehmite nanorods, nano-silica, and silane coupling agent is designed on the outermost layer. This enables the film to achieve ultra-low reflection across a wide spectrum and effective anti-glare while obtaining excellent mechanical durability. It fundamentally overcomes the industry problems of easy peeling of the film layer and easy wear of the anti-glare microstructure, and successfully prepares a high-performance, long-life optical thin film suitable for harsh environments and high-frequency interaction scenarios. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the average light transmittance of each group in the experimental examples of the present invention; Figure 3 This is a schematic diagram of the average reflectance of each group in the test examples of the present invention; Figure 4 This is a schematic diagram of the nanohardness of each group in the test examples of this invention; Figure 5 This is a schematic diagram showing the changes in transmittance of each group in the experimental examples of this invention. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In existing technologies, optical thin films that achieve anti-glare and anti-reflection functions typically employ two main approaches: one is to reduce reflectivity in specific wavelength bands by depositing multilayer dielectric films and utilizing the principle of destructive interference; the other is to construct micro / nano rough surfaces to scatter incident light and suppress specular reflection. However, while pursuing excellent optical performance across wide angles and wavelengths, existing solutions face significant challenges in terms of mechanical durability. On the one hand, multilayer antireflective coatings that rely on precise thickness control have physical interfaces between their layers. These interfaces are not only weak points in stress, affecting the bonding strength between the film and the substrate and between the film layers, but they can also become the starting point for crack initiation and propagation under mechanical friction or impact, leading to irreversible degradation of optical performance.

[0022] On the other hand, the mechanical strength of the micro-nano structures in anti-glare functional layers based on surface morphology control is generally insufficient. Under conditions such as daily cleaning, touching, or friction from sand and dust, the surface protrusions are easily worn down, causing the anti-glare (AG) effect to gradually decline or even be completely lost. At the same time, the wear of the surface morphology directly changes its light scattering characteristics, not only causing increased haze and decreased light transmittance, but also potentially generating unnecessary stray light, affecting imaging contrast and system signal-to-noise ratio.

[0023] Therefore, one of the objectives of this invention is to provide a highly wear-resistant, anti-glare, and anti-reflective optical film, which comprises, from bottom to top: an optical substrate, a bonding layer, an anti-reflective functional layer, and a composite anti-glare and wear-resistant layer, wherein the composite anti-glare and wear-resistant layer comprises the following raw materials in the following mass percentages: The composition consists of 40-60% nano-alumina particles, 35-55% nano-silica particles, 0.5-2.5% silane coupling agent, and the remainder is organic solvent and hydrolysis catalyst.

[0024] In this invention, nano-alumina serves as the hard skeleton and main wear-resistant phase of the coating, preferably boehmite (γ-AlOOH) nanorods, whose unique morphology can enhance the mechanical interlocking between particles and further improve the toughness of the coating. Nano-silica serves as both a matrix binder and an optical modulation phase. On one hand, its abundant surface hydroxyl groups provide reaction sites for silane coupling agents; on the other hand, its refractive index matches that of alumina, ensuring high light transmittance of the coating. The proportion of nano-silica needs to be appropriately matched with alumina to ensure the formation of a continuous and dense composite network. Silane coupling agents serve as crucial "chemical bridges." Their dosage is calculated based on the total surface area of ​​the nanoparticles to ensure effective coating. A dosage below 0.5% results in incomplete modification and insignificant reinforcement; a dosage above 2.5% may affect coating uniformity due to self-polymerization. γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560) is preferred, as its epoxy groups can participate in further crosslinking, strengthening the network. Organic solvents and hydrolysis catalysts are used to prepare stable coating sols. The specific types and proportions are determined according to the selected sol-gel process and do not constitute a limitation on the core functional components.

[0025] Furthermore, the antireflective functional layer has a continuous or quasi-continuous gradient change in refractive index from the bonding layer outwards, and is composed of alternating layers of high refractive index material and low refractive index material. The high-refractive-index material layer is made from a mixture of hafnium dioxide and aluminum oxide, with a molar ratio of hafnium dioxide to aluminum oxide of 7:3. This specific ratio allows for achieving a high refractive index while simultaneously providing the film with the lowest compressive stress and optimal interfacial bonding strength.

[0026] The low-refractive-index material layer is made of silicon dioxide, with a refractive index of approximately 1.46 (@550nm).

[0027] The total physical thickness of the antireflective functional layer is 300-600nm, and its design goal is to make the average reflectivity of the optical film in the visible light band of 420nm to 680nm less than 0.3%.

[0028] Please see Figure 1 As shown, a second objective of this invention is to provide a method for preparing the aforementioned high wear-resistant, anti-glare, and anti-reflection optical thin film, comprising the following steps: Step S1: Weigh the raw materials according to the mass ratio; Then, optical substrate pretreatment is performed, and bonding layer deposition is carried out on the optical substrate; The optical substrate pretreatment involves providing an optical glass or polycarbonate substrate, followed by ultrasonic cleaning, plasma cleaning, and baking to remove moisture. Ultrasonic cleaning uses acetone, ethanol, and deionized water for 15 minutes each; plasma cleaning is performed in an oxygen atmosphere at a power of 300W for 5 minutes to thoroughly remove organic contaminants and activate surface hydroxyl groups; subsequently, the substrate is dried in a 120°C oven for 30 minutes and then transferred to the coating chamber.

[0029] The bonding layer was deposited using reactive magnetron sputtering on a pretreated substrate. A high-purity silicon target was used, and sputtering was performed in an argon-oxygen mixed atmosphere (Ar:O2 = 20:5 sccm) at a working pressure of 0.3 Pa. The deposition power was 300 W, the substrate temperature was maintained at 250℃, and the deposition time was controlled at 8-10 min, resulting in a dense and uniform silicon dioxide bonding layer with a thickness of 20-30 nm.

[0030] Step S2: This step employs a combination of multi-target co-sputtering and sequential deposition to construct a hafnium dioxide-aluminum oxide / silicon dioxide graded refractive index multilayer film system on the bonding layer, serving as an anti-reflection functional layer in the optical thin film. Wherein: High refractive index material layer deposition: Co-sputtering with Hf and Al targets was employed. By independently controlling the sputtering power of the two targets, the deposition of a mixture with a molar ratio of hafnium dioxide to aluminum oxide of 7:3 was precisely achieved. Specifically, in an argon-oxygen mixed atmosphere, the Hf target power was set to 150W and the Al target power to 65W, and a high refractive index layer was formed through deposition over 30 minutes.

[0031] Deposition of low refractive index material layer: With Al target off, only Si target is used for reactive sputtering under the same argon-oxygen atmosphere to deposit a pure silicon dioxide layer for 25 min.

[0032] During the deposition of each high- and low-refractive-index material layer, a computer program linearly adjusts the power of the Hf and Al targets during the initial and final 1-3 minute periods. This ensures a quasi-continuous gradual change in chemical composition and refractive index between layers, rather than an abrupt interface. The deposition process of high- and low-refractive-index material layers is repeated alternately for 4-5 cycles.

[0033] Step S3: In a mixed solvent of anhydrous ethanol and deionized water (mass ratio 9:1), nano-alumina (boehmite (γ-AlOOH) nanorods), nano-silica particles, and a silane coupling agent (KH560 silane coupling agent) are added sequentially. A trace amount of glacial acetic acid is added as a hydrolysis catalyst, and the pH is adjusted to 4-5. The mixture is continuously mechanically stirred and refluxed in a 60℃ water bath for 4-8 hours, followed by aging for 24 hours. The mixture is then filtered through a 0.22μm filter membrane to obtain a homogeneous and stable composite sol.

[0034] Coating and Pre-curing: The coating substrate obtained in step S2 is placed on a spin coater and coated with the above-mentioned composite sol using a spin coating method. For example, a low-speed dispensing setting (500 rpm, 10 s) is followed by a high-speed spin coating setting (3000 rpm, 30 s). Then, it is preheated on an 80°C hot plate for 10 min, and then transferred to an oven and kept at 150°C for 1 h to complete the sol-gel conversion and preliminary cross-linking, forming a smooth wet gel film.

[0035] Step S4: Align a silicon or quartz template with a biomimetic moth-eye array structure (structural unit period 220nm, height 180nm) with the wet gel membrane and place it in a nanoimprint apparatus. Apply a pressure of 0.4-0.6MPa and maintain it for 2-4 minutes to allow the gel membrane to completely fill the template cavity.

[0036] The optical film is then obtained through structural curing and heat treatment and preserved.

[0037] Specifically, the structural curing process involves maintaining pressure while using ultraviolet light irradiation (wavelength 365nm, intensity 100mW / cm², irradiation time 60s) or thermal curing (holding at 180℃ for 30min) to completely solidify the gel film into a hard ceramic layer. After cooling to room temperature, the pressure is released, and the film is gently demolded, thereby accurately replicating a high-fidelity anti-glare micro / nano structure on the surface of the composite anti-glare and wear-resistant layer.

[0038] The heat treatment involves placing the demolded product into a muffle furnace and annealing it in an air atmosphere at 400-600℃ for 1-3 hours. This step aims to completely remove residual organic matter, promote the complete densification of the Si-O-Si and Al-O-Si networks, and achieve the highest hardness, bonding strength, and optical stability of the coating.

[0039] The following specific embodiments will further illustrate the high wear-resistant, anti-glare, and anti-reflection optical thin film and its preparation method provided by the present invention.

[0040] Example 1 Step S1: Weigh out 40% nano alumina particles, 55% nano silica particles, and 0.5% silane coupling agent according to the mass ratio, with the remainder being a hydrolysis catalyst; Then, optical substrate pretreatment is performed, and bonding layer deposition is carried out on the optical substrate; The optical substrate pretreatment involves providing an optical glass or polycarbonate substrate, followed by ultrasonic cleaning, plasma cleaning, and baking to remove moisture. Ultrasonic cleaning uses acetone, ethanol, and deionized water for 15 minutes each; plasma cleaning is performed in an oxygen atmosphere at a power of 300W for 5 minutes to thoroughly remove organic contaminants and activate surface hydroxyl groups; subsequently, the substrate is dried in a 120°C oven for 30 minutes and then transferred to the coating chamber.

[0041] The bonding layer was deposited using reactive magnetron sputtering on a pretreated substrate. A high-purity silicon target was used, and sputtering was performed in an argon-oxygen mixed atmosphere (Ar:O2 = 20:5 sccm) at a working pressure of 0.3 Pa. The deposition power was 300 W, the substrate temperature was maintained at 250 °C, and the deposition time was controlled to 10 min, resulting in a dense and uniform silicon dioxide bonding layer with a thickness of 20 nm.

[0042] Step S2: This step employs a combination of multi-target co-sputtering and sequential deposition to construct a hafnium dioxide-aluminum oxide / silicon dioxide graded refractive index multilayer film system on the bonding layer, serving as an anti-reflection functional layer in the optical thin film. Wherein: High refractive index material layer deposition: Co-sputtering with Hf and Al targets was employed. By independently controlling the sputtering power of the two targets, the deposition of a mixture with a molar ratio of hafnium dioxide to aluminum oxide of 7:3 was precisely achieved. Specifically, in an argon-oxygen mixed atmosphere, the Hf target power was set to 150W and the Al target power to 65W, and a high refractive index layer was formed through deposition over 30 minutes.

[0043] Deposition of low refractive index material layer: With Al target off, only Si target is used for reactive sputtering under the same argon-oxygen atmosphere to deposit a pure silicon dioxide layer for 25 min.

[0044] During the deposition of each high- and low-refractive-index material layer, a computer program linearly adjusts the power of the Hf and Al targets during the initial and final 3-minute intervals. This ensures a quasi-continuous gradual change in chemical composition and refractive index between layers, rather than an abrupt interface. The deposition process of the high- and low-refractive-index material layers is repeated alternately for four cycles, with a total physical thickness of 600 nm for the anti-reflective functional layer.

[0045] Step S3: In a mixed solvent of anhydrous ethanol and deionized water (mass ratio 9:1), nano-alumina (boehmite (γ-AlOOH) nanorods), nano-silica particles, and a silane coupling agent (KH560 silane coupling agent) were added sequentially. A trace amount of glacial acetic acid was added as a hydrolysis catalyst, and the pH was adjusted to 4. The mixture was continuously mechanically stirred and refluxed in a 60°C water bath for 8 hours, followed by aging for 24 hours. The mixture was then filtered through a 0.22 μm filter membrane to obtain a homogeneous and stable composite sol.

[0046] Coating and Pre-curing: The coating substrate obtained in step S2 is placed on a spin coater and coated with the above-mentioned composite sol using a spin coating method. For example, a low-speed dispensing setting (500 rpm, 10 s) is followed by a high-speed spin coating setting (3000 rpm, 30 s). Then, it is preheated on an 80°C hot plate for 10 min, and then transferred to an oven and kept at 150°C for 1 h to form a smooth wet gel film.

[0047] Step S4: Align a silicon or quartz template with a biomimetic moth-eye array structure (structural unit period 220nm, height 180nm) with the wet gel film and place it in a nanoimprint apparatus. Apply a pressure of 0.4MPa and maintain it for 4min to allow the gel film to completely fill the template cavity. Then, perform structural curing and heat treatment to obtain an optical thin film and store it.

[0048] Specifically, the structural curing process involves irradiating the gel film with ultraviolet light (wavelength 365nm, intensity 100mW / cm², irradiation time 60s) while maintaining pressure, causing the gel film to completely solidify into a hard ceramic layer. After cooling to room temperature, the pressure is released, and the film is gently demolded.

[0049] The heat treatment involved placing the demolded product into a muffle furnace and annealing it at 400°C in an air atmosphere for 3 hours.

[0050] Example 2 Step S1: Weigh out 50% nano alumina particles, 45% nano silica particles, and 1.5% silane coupling agent according to the mass ratio, with the remainder being a hydrolysis catalyst; Then, optical substrate pretreatment is performed, and bonding layer deposition is carried out on the optical substrate; The optical substrate pretreatment involves providing an optical glass or polycarbonate substrate, followed by ultrasonic cleaning, plasma cleaning, and baking to remove moisture. Ultrasonic cleaning uses acetone, ethanol, and deionized water for 15 minutes each; plasma cleaning is performed in an oxygen atmosphere at a power of 300W for 5 minutes to thoroughly remove organic contaminants and activate surface hydroxyl groups; subsequently, the substrate is dried in a 120°C oven for 30 minutes and then transferred to the coating chamber.

[0051] The bonding layer was deposited using reactive magnetron sputtering on a pretreated substrate. A high-purity silicon target was used, and sputtering was performed in an argon-oxygen mixture atmosphere (Ar:O2 = 20:5 sccm) at a working pressure of 0.3 Pa. The deposition power was 300 W, the substrate temperature was maintained at 250 °C, and the deposition time was controlled at 9 min, resulting in a dense and uniform silicon dioxide bonding layer with a thickness of 25 nm.

[0052] Step S2: This step employs a combination of multi-target co-sputtering and sequential deposition to construct a hafnium dioxide-aluminum oxide / silicon dioxide graded refractive index multilayer film system on the bonding layer, serving as an anti-reflection functional layer in the optical thin film. Wherein: High refractive index material layer deposition: Co-sputtering with Hf and Al targets was employed. By independently controlling the sputtering power of the two targets, the deposition of a mixture with a molar ratio of hafnium dioxide to aluminum oxide of 7:3 was precisely achieved. Specifically, in an argon-oxygen mixed atmosphere, the Hf target power was set to 150W and the Al target power to 65W, and a high refractive index layer was formed through deposition over 30 minutes.

[0053] Deposition of low refractive index material layer: With Al target off, only Si target is used for reactive sputtering under the same argon-oxygen atmosphere to deposit a pure silicon dioxide layer for 25 min.

[0054] During the deposition of each high- and low-refractive-index material layer, a computer program linearly adjusts the power of the Hf and Al targets during the initial and final 2-minute intervals. This ensures a quasi-continuous gradual change in chemical composition and refractive index between layers, rather than an abrupt interface. The deposition process of the high- and low-refractive-index material layers is repeated alternately for five cycles, with a total physical thickness of 400 nm for the anti-reflective functional layer.

[0055] Step S3: In a mixed solvent of anhydrous ethanol and deionized water (mass ratio 9:1), nano-alumina (boehmite (γ-AlOOH) nanorods), nano-silica particles, and a silane coupling agent (KH560 silane coupling agent) were added sequentially. A trace amount of glacial acetic acid was added as a hydrolysis catalyst, and the pH was adjusted to 5. The mixture was continuously mechanically stirred and refluxed in a 60°C water bath for 6 hours, followed by aging for 24 hours. The mixture was then filtered through a 0.22 μm filter membrane to obtain a homogeneous and stable composite sol.

[0056] Coating and Pre-curing: The coating substrate obtained in step S2 is placed on a spin coater and coated with the above-mentioned composite sol using a spin coating method. For example, a low-speed dispensing setting (500 rpm, 10 s) is followed by a high-speed spin coating setting (3000 rpm, 30 s). Then, it is preheated on an 80°C hot plate for 10 min, and then transferred to an oven and kept at 150°C for 1 h to form a smooth wet gel film.

[0057] Step S4: Align a silicon or quartz template with a biomimetic moth-eye array structure (structural unit period 220nm, height 180nm) with the wet gel film and place it in a nanoimprint apparatus. Apply a pressure of 0.5MPa and maintain it for 3 minutes to allow the gel film to completely fill the template cavity. Then, perform structural curing and heat treatment to obtain an optical thin film and store it.

[0058] Specifically, the structural curing process involves irradiating the gel film with ultraviolet light (wavelength 365nm, intensity 100mW / cm², irradiation time 60s) while maintaining pressure, causing the gel film to completely solidify into a hard ceramic layer. After cooling to room temperature, the pressure is released, and the film is gently demolded.

[0059] The heat treatment involved placing the demolded product into a muffle furnace and annealing it at 500°C in an air atmosphere for 2 hours.

[0060] Example 3 Step S1: Weigh out 60% nano alumina particles, 35% nano silica particles, and 2.5% silane coupling agent according to the mass ratio, with the remainder being a hydrolysis catalyst; Then, optical substrate pretreatment is performed, and bonding layer deposition is carried out on the optical substrate; The optical substrate pretreatment involves providing an optical glass or polycarbonate substrate, followed by ultrasonic cleaning, plasma cleaning, and baking to remove moisture. Ultrasonic cleaning uses acetone, ethanol, and deionized water for 15 minutes each; plasma cleaning is performed in an oxygen atmosphere at a power of 300W for 5 minutes to thoroughly remove organic contaminants and activate surface hydroxyl groups; subsequently, the substrate is dried in a 120°C oven for 30 minutes and then transferred to the coating chamber.

[0061] The bonding layer was deposited using reactive magnetron sputtering on a pretreated substrate. A high-purity silicon target was used, and sputtering was performed in an argon-oxygen mixture atmosphere (Ar:O2 = 20:5 sccm) at a working pressure of 0.3 Pa. The deposition power was 300 W, the substrate temperature was maintained at 250 °C, and the deposition time was controlled to 8 min, resulting in a dense and uniform silicon dioxide bonding layer with a thickness of 30 nm.

[0062] Step S2: This step employs a combination of multi-target co-sputtering and sequential deposition to construct a hafnium dioxide-aluminum oxide / silicon dioxide graded refractive index multilayer film system on the bonding layer, serving as an anti-reflection functional layer in the optical thin film. Wherein: High refractive index material layer deposition: Co-sputtering with Hf and Al targets was employed. By independently controlling the sputtering power of the two targets, the deposition of a mixture with a molar ratio of hafnium dioxide to aluminum oxide of 7:3 was precisely achieved. Specifically, in an argon-oxygen mixed atmosphere, the Hf target power was set to 150W and the Al target power to 65W, and a high refractive index layer was formed through deposition over 30 minutes.

[0063] Deposition of low refractive index material layer: With Al target off, only Si target is used for reactive sputtering under the same argon-oxygen atmosphere to deposit a pure silicon dioxide layer for 25 min.

[0064] During the deposition of each high- and low-refractive-index material layer, a computer program linearly adjusts the power of the Hf and Al targets during the initial and final 1-minute intervals. This ensures a quasi-continuous gradual change in chemical composition and refractive index between layers, rather than an abrupt interface. The deposition process of the high- and low-refractive-index material layers is repeated alternately for five cycles, with a total physical thickness of 300 nm for the anti-reflective functional layer.

[0065] Step S3: In a mixed solvent of anhydrous ethanol and deionized water (mass ratio 9:1), nano-alumina (boehmite (γ-AlOOH) nanorods), nano-silica particles, and a silane coupling agent (KH560 silane coupling agent) were added sequentially. A trace amount of glacial acetic acid was added as a hydrolysis catalyst, and the pH was adjusted to 5. The mixture was continuously mechanically stirred and refluxed in a 60°C water bath for 4 hours, followed by aging for 24 hours. The mixture was then filtered through a 0.22 μm filter membrane to obtain a homogeneous and stable composite sol.

[0066] Coating and Pre-curing: The coating substrate obtained in step S2 is placed on a spin coater and coated with the above-mentioned composite sol using a spin coating method. For example, a low-speed dispensing setting (500 rpm, 10 s) is followed by a high-speed spin coating setting (3000 rpm, 30 s). Then, it is preheated on an 80°C hot plate for 10 min, and then transferred to an oven and kept at 150°C for 1 h to form a smooth wet gel film.

[0067] Step S4: Align a silicon or quartz template with a biomimetic moth-eye array structure (structural unit period 220nm, height 180nm) with the wet gel film and place it in a nanoimprint apparatus. Apply a pressure of 0.6MPa and maintain it for 2 minutes to allow the gel film to completely fill the template cavity. Then, perform structural curing and heat treatment to obtain an optical thin film and store it.

[0068] Specifically, the structural curing process involves heat curing (holding at 180°C for 30 minutes) while maintaining pressure, allowing the gel film to completely solidify into a hard ceramic layer. After cooling to room temperature, the pressure is released, and the film is gently demolded.

[0069] The heat treatment involved placing the demolded product into a muffle furnace and annealing it at 600°C in an air atmosphere for 1 hour.

[0070] After preparing the optical thin films according to Examples 1-3, the optical thin films were subjected to the following performance tests: 1. Comprehensive optical performance testing I. Samples and Equipment Sample preparation: Use at least 3 independent samples of the finished films prepared in Examples 1-3, cut to appropriate size, and ensure that there are no visible defects in the test area.

[0071] Core equipment: UV-Vis-NIR spectrophotometer (equipped with an integrating sphere), fully automatic haze meter (according to GB / T2410 standard), and high-resolution spectral ellipsometer.

[0072] Test method: Using an integrating sphere spectrophotometer, the spectral transmittance (T%) and spectral reflectance (R%) of the samples were measured in the visible light band from 400 nm to 700 nm, calibrated with air or a standard substrate as 100% baseline. T-λ and R-λ curves were plotted, and the average transmittance (Tavg) and average reflectance (Ravg) in the 420 nm to 680 nm band were calculated. The results are recorded in Table 1.

[0073] 2. Core mechanical durability testing I. Samples and Equipment Sample preparation: Same as optical testing samples, but additional control samples are required (such as thin films with similar structures but not reinforced with silane coupling agents).

[0074] Core equipment: scratch tester (or adhesion tester), nano-indentation tester, sand / steel wool abrasion tester, Taber abrasion tester.

[0075] Hardness testing: The nanohardness of the film surface was measured using the nanoindentation method. Multiple points were selected on the sample surface for measurement, and the average value was taken.

[0076] Abrasion resistance test: Using a Taber abrasion tester, the samples were subjected to an abrasion test at 500 revolutions with a specific abrasive wheel (e.g., CS-10) and a load (e.g., 500g). The change in light transmittance was measured after the test, and the results are recorded in Table 1.

[0077] Table 1. Properties of the optical thin films prepared in Examples 1-3 As shown in Table 1, the average transmittance of the optical films prepared in Examples 1-3 is not less than 95.5%, the average reflectance is not more than 0.30%, the surface hardness is not less than 15.1 GPa, and the transmittance variation is not greater than 1%, indicating that the prepared optical films have good optical performance and durability.

[0078] In this invention, a multilayer film system is constructed by alternating layers of hafnium dioxide-aluminum oxide (HfO2-Al2O3) mixture as the high-refractive-index material layer and low-refractive-index silicon dioxide (SiO2), achieving a continuous or quasi-continuous gradient change in refractive index. This specific material ratio and structural design effectively reduces clear physical interfaces between layers, significantly lowers residual stress within the film, optimizes the bonding strength between the film and the substrate and between each layer from the root, and significantly improves the mechanical stability and crack initiation resistance of the film system.

[0079] In the core composite anti-glare and wear-resistant layer, nano-alumina particles, such as boehmite (γ-AlOOH) nanorods, serve as a hard framework and a physically wear-resistant phase. Their unique rod-like morphology constructs a high-strength physical reinforcement network through mechanical interlocking. Nano-silica particles act as a matrix binder and optical modulation phase, with abundant hydroxyl groups on their surface providing reaction sites for subsequent chemical bonding. As a key technology, the silane coupling agent undergoes hydrolysis and condensation reactions with the hydroxyl groups on the surface of the nano-SiO2 particles and the underlying anti-reflection functional layer during the sol-gel process, constructing a three-dimensional Si-O-Si covalent bond network that penetrates the nanoparticles and interlayer interfaces in situ. This "chemical rivet" effect firmly anchors the physical reinforcement network to the substrate, achieving a significant improvement in the coating's cohesive strength and interfacial bonding.

[0080] During the fabrication process, precise and continuous control of the chemical composition and optical properties of the graded refractive index antireflective functional layer was achieved through multi-target magnetron co-sputtering and computer program precision control, eliminating weak interfaces with abrupt performance changes. Subsequently, a high-fidelity biomimetic moth-eye micro / nano structure was precisely replicated on the surface of a composite sol layer chemically reinforced with a silane coupling agent using a sol-gel method combined with nanoimprinting technology. Finally, a controlled heat treatment process was used to completely remove residual organic matter and promote the complete densification of the inorganic network, ultimately curing to form a ceramic composite coating that combines ultra-low reflection, effective anti-glare, and extremely high mechanical wear resistance.

[0081] In summary, this invention, through the deep integration of "gradient refractive index film system design" and "chemical-physical synergistic enhancement composite structure", fundamentally and synergistically solves two common industry problems of insufficient bonding force due to interlayer interface stress concentration in traditional anti-glare and anti-reflection optical films, and easy wear and functional degradation due to low mechanical strength of surface micro-nano structures. It successfully prepares high-performance, long-life optical films suitable for harsh environments and high-frequency interaction scenarios.

[0082] Experimental Example 1 To verify that the graded refractive index design of the HfO2-Al2O3 mixture, the in-situ chemical reinforcement of the silane coupling agent, and the boehmite nanorod morphology effect are key to achieving a synergistic improvement in "high bonding strength" and "high wear resistance" in the high wear-resistant anti-glare and anti-reflection optical film of this invention, this experimental example is based on the formulation and process of Example 2 (representing the optimal solution of this invention), changing only a single core technical variable, and designing the following three sets of comparative experiments: Control group D1: Chemically enhanced group without silane coupling agent Solution: When preparing the composite anti-glare and wear-resistant layer sol, KH560 silane coupling agent is not added at all. The proportions of other raw materials (50% nano alumina and 45% nano silica) and all preparation process steps are exactly the same as in Example 2.

[0083] Objective: To isolate and verify the decisive role of silane coupling agents as "chemical rivets" in improving film adhesion and wear resistance. The aim is to contrast the coating interior and the interface with the underlying layer, which rely solely on physical adsorption and lack a covalently bonded network.

[0084] Comparison Group D2: Traditional TiO2 / SiO2 stacked antireflection layer group Solution: The material system of the anti-reflective functional layer is changed from "HfO2-Al2O3 mixture / SiO2 gradient refractive index design" to conventional TiO2 (titanium dioxide) / SiO2 alternating stacking, and no interlayer gradient transition (i.e., clear interface) is set. The optical thickness of the TiO2 layer and SiO2 layer remains λ / 4, and the total number of cycles (5 cycles) and physical thickness (approximately 400nm) are as close as possible to Example 2. The formulation and process of the composite anti-glare and wear-resistant layer are exactly the same as in Example 2.

[0085] Objective: To verify the advantages of the specific HfO2-Al2O3 mixture and gradient interface design of this invention in reducing film stress and improving bonding strength compared with traditional high refractive index materials (such as TiO2).

[0086] Control group D3: Spherical nano-alumina physically reinforced group Solution: Replace the boehmite (γ-AlOOH) nanorods in the composite anti-glare and wear-resistant layer with spherical α-Al2O3 nanoparticles of equal mass and particle size (approximately 50 nm). The remaining raw material ratios and all preparation process steps are exactly the same as in Example 2.

[0087] Objective: To verify the necessity of boehmite nanorods' unique rod-like morphology, which forms a physically reinforcing network through mechanical interlocking, for improving coating toughness and wear resistance. Spherical particles were expected to provide only simple filler reinforcement.

[0088] Following the identical "comprehensive optical performance testing" and "core mechanical durability testing" methods described above, the products of the aforementioned comparative groups D1, D2, and D3 were subjected to performance tests, and the results were compared with those of Example 2. Key data are as follows: Figure 2-5 As shown.

[0089] according to Figure 2-5 It can be known that, The critical role of chemical reinforcement by silane coupling agents (Example 2 and Comparative Group D1) Results: In the control group D1, the wear resistance deteriorated sharply without the use of silane coupling agent. The light transmittance loss after Taber wear was also much higher than that of the present invention.

[0090] Mechanism: The hydrolysis-condensation reaction of the silane coupling agent (KH560) is the only way to construct a three-dimensional Si-O-Si covalent network that runs through the interfaces between nanoparticles and between particles and the underlying film in situ. Without this "chemical rivet," the coating relies solely on physical adsorption and van der Waals forces for bonding, resulting in a significant reduction in cohesive strength and interfacial bonding energy. Under mechanical friction, nanoparticles are easily "pulled out" or peel off entirely, leading to rapid failure of the micro / nano structure. This comparison strongly demonstrates that the introduction of the silane coupling agent is the core chemical method for solving the problems of insufficient bonding strength and wear resistance in this solution.

[0091] Superiority of hafnium dioxide-aluminum oxide gradient refractive index design (Example 2 and Comparative Group D2) Results: The wear resistance of control group D2, which uses a conventional TiO2 / SiO2 clear interface stack, was significantly worse than that of Example 2. Although the initial optical performance was acceptable, its performance degraded more severely after mechanical testing.

[0092] Mechanism: TiO2 films typically exhibit high intrinsic stress, and the interface between the TiO2 film and the SiO2 film is clear, making it prone to stress concentration points. The hafnium dioxide-aluminum oxide mixture (7:3 molar ratio) used in this invention, after optimization, achieves a more ideal stress state. More importantly, by setting a gradient transition region with linearly varying power between layers, a quasi-continuous change in refractive index and chemical composition is achieved, effectively eliminating the clear physical interface and uniformly dispersing stress, thereby significantly improving the mechanical robustness and crack propagation resistance of the film stack. This comparison demonstrates that the antireflection layer design of this invention is not a simple material replacement, but a structural innovation aimed at improving reliability.

[0093] The necessity of enhancing the morphology of boehmite nanorods (Example 2 and Control Group D3) Results: The control group D3, which used spherical alumina, had lower nanohardness and wear resistance than Example 2. In particular, after the wear resistance test, its performance degradation was between that of Example 2 and control group D1.

[0094] Mechanism: Spherical particles primarily provide uniform dispersion reinforcement. Boehmite nanorods, due to their high aspect ratio (5:1 to 10:1), can oriented and intertwine during coating curing, forming a mechanically interlocked network similar to a "straw mat." This network can more effectively transfer and disperse external stress, consuming more fracture energy, thus significantly improving the coating's toughness while imparting high hardness. Therefore, it exhibits stronger resistance to plastic deformation and spalling under friction. This comparison demonstrates that the morphology design of the physical reinforcing phase is a crucial physical basis for achieving exceptional wear resistance and durability.

[0095] Conclusion: The comparative experiments above fully demonstrate that the "hafnium dioxide-aluminum oxide gradient refractive index film system (optimized stress and bonding)," "boehmite nanorods (physical interlocking enhancement)," and "silane coupling agent in-situ chemical bonding (chemical anchoring)" constitute an organically synergistic and indispensable technical system. The absence or substitution of any single feature will lead to an observable and significant degradation in the film's key mechanical durability indicators.

[0096] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a highly wear-resistant, anti-glare, and anti-reflective optical thin film, characterized in that, Includes the following steps: Step S1: Weigh out 40-60% nano alumina particles, 35-55% nano silica particles, and 0.5-2.5% silane coupling agent according to the mass ratio, with the remainder being a hydrolysis catalyst; Then, optical substrate pretreatment is performed, and bonding layer deposition is carried out on the optical substrate; Step S2: Using a process combining multi-target co-sputtering and sequential deposition, a multilayer film system with alternating high-refractive-index material layers and low-refractive-index material layers is constructed on the bonding layer to serve as an anti-reflection functional layer in the optical thin film. Step S3: In a mixed solvent of anhydrous ethanol and deionized water, nano-alumina, nano-silica particles, and silane coupling agent are added sequentially, followed by the addition of a hydrolysis catalyst, and the mixture is mechanically stirred to form a composite sol. The coating substrate obtained in step S2 is placed on a spin coater, and a composite sol is coated by spin coating. Then, a wet gel film is obtained after pre-curing treatment. Step S4: Align the template with the biomimetic moth eye array structure with the wet gel membrane, place it in the nanoimprint device, apply a pressure of 0.4-0.6 MPa and maintain it for 2-4 minutes to allow the gel membrane to completely fill the template cavity; Optical films are obtained and preserved through structural curing and heat treatment.

2. The method for preparing the high wear-resistant, anti-glare, and anti-reflective optical thin film according to claim 1, characterized in that: In step S2, the anti-reflection functional layer is composed of alternating layers of high-refractive-index material and low-refractive-index material from the self-bonding layer outwards. The raw material for the high refractive index material layer is a mixture of hafnium dioxide and aluminum oxide, wherein the molar ratio of hafnium dioxide to aluminum oxide is 7:3; The raw material for the low refractive index material layer is silicon dioxide.

3. The method for preparing the high wear-resistant, anti-glare, and anti-reflective optical thin film according to claim 2, characterized in that: The high refractive index material layer deposition: Hf target and Al target co-sputtering is used, and the sputtering power of the two targets is independently controlled to achieve the deposition of a mixture with a molar ratio of 7:3 of hafnium dioxide and aluminum oxide. Deposition of low refractive index material layer: With Al target off, only Si target is used for reactive sputtering under the same argon-oxygen atmosphere to deposit a pure silicon dioxide layer for 25 min.

4. The method for preparing the high wear-resistant, anti-glare, and anti-reflective optical thin film according to claim 3, characterized in that: The deposition process of the high- and low-refractive-index material layers is repeated alternately for 4-5 cycles; During the deposition of each high- and low-refractive-index material layer, the power of the Hf target and the Al target is linearly adjusted during the 1-3 minute period at the beginning and end, so that the chemical composition and refractive index between layers can achieve a quasi-continuous gradual change.

5. The method for preparing the high wear-resistant, anti-glare, and anti-reflective optical thin film according to claim 4, characterized in that: The total physical thickness of the antireflection functional layer is 300-600 nm.

6. The method for preparing the high wear-resistant, anti-glare, and anti-reflective optical thin film according to claim 1, characterized in that: In step S3, the mixture is continuously mechanically stirred and refluxed in a 60°C water bath for 4-8 hours, then aged for 24 hours, and filtered using a 0.22μm filter membrane to obtain a uniform and stable composite sol.

7. The method for preparing the high wear-resistant, anti-glare, and anti-reflective optical thin film according to claim 1, characterized in that: In step S3, the pre-curing process involves placing the product on an 80°C hot plate for 10 minutes, then transferring it to an oven and maintaining it at 150°C for 1 hour to form a smooth wet gel film.

8. The method for preparing the high wear-resistant, anti-glare, and anti-reflective optical thin film according to claim 1, characterized in that: In step S4, the structural curing process involves using ultraviolet light irradiation or thermal curing under pressure to completely solidify the gel film into a hard ceramic layer. After cooling to room temperature, release the pressure and gently demold to replicate a high-fidelity anti-glare micro-nano structure on the surface of the composite anti-glare and wear-resistant layer.

9. The method for preparing the high wear-resistant, anti-glare, and anti-reflective optical thin film according to claim 1, characterized in that: In step S4, the heat treatment involves placing the demolded product into a muffle furnace and annealing it in an air atmosphere at 400-600°C for 1-3 hours.

10. A highly wear-resistant, anti-glare, and anti-reflective optical thin film prepared by the preparation method according to any one of claims 2-9, comprising, from bottom to top: The optical substrate, bonding layer, anti-reflective functional layer, and composite anti-glare and wear-resistant layer are characterized by: The antireflective functional layer is a gradient refractive index film system constructed by alternating hafnium dioxide-aluminum oxide mixture and silicon dioxide. Hafnium dioxide and aluminum oxide are combined in a specific molar ratio of 7:3 as the high refractive index material layer, which effectively optimizes the film stress and interfacial bonding strength. Silicon dioxide, as the low refractive index material layer, is deposited alternately with the high refractive index layer through a multi-target co-sputtering process, and a quasi-continuous gradient transition of chemical composition and refractive index is achieved at the interlayer interface to eliminate the stress concentration and crack initiation risk caused by a clear physical interface. The composite anti-glare and wear-resistant layer is an inorganic nanocomposite ceramic coating, comprising nano-alumina particles as a hard wear-resistant skeleton, nano-silica particles as a matrix bonding and optical control phase, and a silane coupling agent as a chemical bonding bridge. The silane coupling agent undergoes hydrolysis and condensation during film formation, generating a three-dimensional Si-O-Si covalent bond network that penetrates the nanoparticles and the interlayer interface in situ. This firmly anchors the physical reinforcement network to the lower film system, synergistically improving the intrinsic strength of the coating, the interfacial bonding force, and the mechanical durability of the surface micro-nano anti-glare structure.

Images