Long-acting weather-resistant curved glass mirror and method for manufacturing the same

Abstract

The application specifically relates to a long-acting weather-resistant curved glass reflector and a preparation method thereof, which comprises the following steps: taking a shaped hot-bent free-form curved glass as a substrate, sequentially performing multi-stage ultrasonic cleaning, drying and plasma surface activation treatment, depositing an aluminum oxide bottom layer film by adopting an ALD process, alternately depositing a niobium pentoxide film layer and a silicon dioxide film layer, and ending with the niobium pentoxide film layer, depositing an aluminum oxide top layer protective film, performing vacuum annealing on the workpiece after film plating to release the internal stress of the film layer, and naturally cooling down with the furnace to obtain the long-acting weather-resistant curved glass reflector. The reflector prepared by the application has low absorption and low scattering in the visible light band, significantly improves the HUD imaging clarity, reduces the light machine overheating failure, has high film layer purity and low stress, stable optical performance and excellent consistency, and has excellent vehicle-mounted high weather resistance, effectively solving the industry pain points such as poor film plating uniformity, weak weather resistance and short service life of the traditional HUD curved reflector.

Description

Technical Field

[0001] This invention relates to the field of curved glass reflector technology, specifically to a long-lasting weather-resistant curved glass reflector and its preparation method. Background Technology

[0002] Hot-bent freeform surfaces are formed by high-temperature pressing with molds. They can correct optical path aberrations through aspherical curved surfaces and reduce the volume of optomechanical structures, making them the mainstream optical substrate for high-end automotive AR-HUDs. Hot-bent glass, after being softened and shaped at high temperatures, possesses excellent surface precision and structural stability. However, due to its large curvature and irregular free-form surface structure, traditional planar coating processes struggle to adapt to its complex surface morphology. Current industry coating solutions for HUD hot-bent glass mainly fall into two categories: metallic spectrophotometric coating and conventional PVD dielectric coating, both of which have significant technical drawbacks. While metallic films offer advantages such as good spectrophotometric performance and simple processing, they suffer from significant thermo-optical effects, poor weather resistance, and susceptibility to oxidation and sulfidation. Prolonged exposure to high temperatures, humidity, and ultraviolet radiation in automotive environments can lead to film blackening and reflectivity attenuation, severely impacting HUD imaging clarity and lifespan.

[0003] Conventional PVD magnetron sputtering dielectric coatings are limited by geometric deposition principles, allowing particles to deposit only along straight lines. This can easily lead to shadowing effects in the curved surfaces, high-curvature edges, and sidewalls of hot-bent glass, causing problems such as localized thinner films, incomplete deposition, and uneven film thickness. This results in poor overall optical consistency, leading to defects such as color cast, uneven brightness, rainbow patterns, and ghosting. Furthermore, traditional PVD coatings lack sufficient density, with numerous microscopic pinholes on the surface. Water vapor, salt spray, and corrosive media can easily penetrate to the film-substrate interface, causing film peeling and delamination failure, failing to meet the requirements for long-term durable automotive applications. In addition, traditional PVD magnetron sputtering metal reflective films have inherent optical defects. Metal materials have high visible light absorption coefficients; for example, 90nm Al:visible light absorption is ≈7%–8%, with even greater absorption under strong light / sunlight backflow. Significant light energy absorption loss occurs in the visible light band required for imaging, making it impossible to achieve efficient reflection; at the same time, the rough columnar crystal structure formed by the sputtering process will cause serious visible light scattering problems, producing stray light and diffuse reflection, resulting in HUD imaging brightness reduction, image blurring, reduced contrast and severe glare, which greatly reduces the in-vehicle display experience.

[0004] In summary, existing HUD hot-bending glass coating technologies generally suffer from bottlenecks such as poor surface adaptability, low film uniformity, insufficient optical consistency, and weak weather resistance reliability, making it difficult to meet the mass production requirements of high-definition, high uniformity, and long lifespan for high-end AR-HUDs. Therefore, it is urgent to propose a glass coating solution that adapts to irregular hot-bending surfaces and combines high uniformity and high reliability. Summary of the Invention

[0005] The purpose of this invention is to provide a long-lasting weather-resistant curved glass reflector and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a long-lasting weather-resistant curved glass reflector includes the following steps: S1, Pretreatment: Take the hot-bent free-form glass after molding as the substrate, and perform multi-stage ultrasonic cleaning, drying and plasma surface activation treatment in sequence. S2, Deposition of bottom sealing film: The pretreated hot-bent glass is deposited using the ALD process with trimethylaluminum as a precursor to form an aluminum oxide bottom film. S3, High-reflectivity optical film stack deposition: Continuing to use the ALD process, alternately deposit niobium pentoxide and silicon dioxide films, ending with a niobium pentoxide film; wherein, niobium pentaethoxy is used as a precursor when depositing the niobium pentoxide film, and silane is used as a precursor when depositing the silicon dioxide film, and the film is grown layer by layer according to the preset number of cycles to construct a multilayer dielectric high-reflectivity film system. S4, Top layer weather-resistant protective film deposition: Continuing to use the ALD process, using trimethylaluminum as a precursor, deposit aluminum oxide top layer protective film; S5, Post-processing: After the coating is completed, the workpiece is vacuum annealed to release the internal stress of the film layer and then naturally cooled in the furnace to obtain a long-lasting weather-resistant curved glass reflector.

[0007] Furthermore, the multi-segment ultrasonic cleaning in step S1 includes: sequentially cleaning with pure water, anhydrous ethanol, and propofol using an ultrasonic cleaning process.

[0008] Furthermore, the drying temperature in step S1 is 80-100℃, and the drying time is 15-20 minutes.

[0009] Furthermore, the plasma surface activation treatment in step S1 is as follows: bombardment with oxygen plasma for 3 to 5 minutes.

[0010] Furthermore, in step S2, the pre-treated hot-bent glass is processed using the ALD process within an ALD vacuum coating chamber, with the chamber's base vacuum level controlled to be ≤8×10⁻⁶. -4 Pa, the process temperature is stabilized at 160-180℃; the aluminum oxide bottom film is formed by 182 cycles, and the film thickness is 15-25nm.

[0011] Furthermore, the alternating deposition of niobium pentoxide and silicon dioxide films in step S3 specifically involves: sequentially depositing the following layers on the aluminum oxide underlayer: A single-layer niobium pentoxide film was obtained after 417 cycles; A single-layer silica film was obtained by cycling 614 times. A single-layer niobium pentoxide film was obtained after 564 cycles; A single-layer silica film was obtained by cycling 641 times. A single-layer niobium pentoxide film was obtained after 531 cycles; A single-layer silica film was obtained by cycling 600 times. A single-layer niobium pentoxide film was obtained after 536 cycles; A single-layer silica film was obtained by cycling 656 times. A single-layer niobium pentoxide film was obtained after 610 cycles; A single-layer silica film was obtained by cycling 854 times. A single-layer niobium pentoxide film was obtained after 867 cycles; A single-layer silica film was obtained by cycling 728 times. A single-layer niobium pentoxide film was obtained after 672 cycles; A single-layer silica film was obtained by cycling 1001 times. A single-layer niobium pentoxide film was obtained after 755 cycles; A single-layer silica film was obtained by cycling 784 times. A single-layer niobium pentoxide film was obtained after 906 cycles; A single-layer silica film was obtained by cycling 947 times. A single-layer niobium pentoxide film was obtained through 467 cycles.

[0012] Furthermore, the thickness of the aluminum oxide top protective film is 10-80 nm, obtained through 1807 cycles.

[0013] Furthermore, in the ALD process described in steps S2-S4, argon is used as both the carrier gas and the purging gas, and the adsorption, purging, and oxidant oxidation cycles are completed by alternating pulses.

[0014] Furthermore, the vacuum annealing described in step S5 is performed by annealing at a constant temperature of 120°C for 30 minutes inside a vacuum annealing chamber.

[0015] The present invention also includes a long-lasting weather-resistant curved glass reflector prepared by any of the preparation methods described above.

[0016] This invention replaces the traditional plastic HUD with curved glass. Compared to traditional magnetron sputtering of metal-based reflective films and conventional dielectric coating techniques, it employs atomic layer deposition to prepare a multilayer composite optical film system. This system combines a high-refractive-index niobium pentoxide and a low-refractive-index silicon dioxide alternating stacked structure with an alumina sealing and protective structure. This results in multiple technological advantages, including superior uniformity of the curved coating, strong weather resistance and reliability, and reduced HUD optomechanical thermal failures. Specific beneficial effects are as follows: 1. Low absorption and low scattering in the visible light band significantly improves HUD imaging clarity and reduces optomechanical overheating failures. This invention employs an all-dielectric ALD optical film system, which generates minimal heat and suppresses thermal deformation / damage. The Nb2O5, SiO2, and Al2O3 dielectric materials used possess extremely low visible light absorption and scattering coefficients. The film layer is atomically flat and dense, free of coarse grains and porosity defects, resulting in virtually no visible light absorption loss or stray light scattering loss. Through an alternating interference design of high and low refractive index media, this invention's film system achieves effective high reflectivity in the 400–700 nm visible light imaging band, significantly improving visible light utilization, enhancing HUD imaging brightness and contrast, and ensuring long-term stable and excellent image quality for automotive displays.

[0017] 2. Adapts to freeform surface structures, achieving atomic-level uniform coating across the entire area, resulting in distortion-free imaging. This invention employs atomic layer deposition (ALD) technology, relying on the saturated self-limiting adsorption characteristics of precursor gases. It is unaffected by the angle or curvature of the surface, enabling uniform atomic-level thin film deposition across the entire curved glass surface, including micropores and corners. The film interface is flat and dense, free of pores and stress concentration, with film thickness precision controllable to the 0.1 nm level. This effectively ensures consistent optical performance across the entire curved mirror surface, eliminating defects such as imaging distortion and uneven brightness, significantly improving HUD imaging quality. It also solves the problems of uneven corner deposition, large film thickness deviation, and rough columnar crystal structure that easily cause color difference, spot distortion, and inconsistent reflectivity in HUD imaging when using traditional magnetron sputtering on large-curvature, irregularly shaped, hot-bent glass surfaces.

[0018] 3. Alumina protection, greatly enhancing the vehicle's high weather resistance. This invention employs alumina protection. The alumina film layer possesses excellent density, hydrolysis resistance, UV shielding, and mechanical hardness, effectively blocking the penetration of water vapor, salt spray, ultraviolet rays, and pollutants from complex automotive environments. This prevents problems such as hydrolytic aging, interface peeling, and microcracks in the inner Nb2O5 and SiO2 optical films. Compared to traditional metal films and SiO2 protective films, the film layer of this invention can withstand harsh automotive environmental testing conditions such as high temperature and humidity, thermal cycling, salt spray corrosion, and UV aging. Long-term use shows no issues such as film peeling, flaking, yellowing, or spectral drift, greatly improving the service life and environmental adaptability of curved reflectors.

[0019] 4. The film has high purity, low stress, and stable and consistent optical performance. This invention utilizes a gaseous precursor combined with oxygen plasma oxidation deposition throughout the entire process, resulting in the absence of halogen, hydrocarbon, and other impurities, leading to extremely high film purity and low optical loss. Simultaneously, the ALD deposition process minimizes internal stress in the film, avoiding the drawbacks of traditional sputtering processes such as high stress, susceptibility to cracking, and porous film structure. The multilayer dielectric film system, through precise cycle control, allows for batch replication of uniform spectral parameters and film structures, resulting in high product consistency, strong mass production stability, and suitability for the large-scale mass production needs of automotive HUDs.

[0020] 5. Free from metal film defects, avoiding oxidation blackening and optical attenuation problems. This invention employs an all-dielectric optical film system throughout, abandoning traditional metal reflective layers such as Al and Ag. It completely solves the industry pain points of metal films being prone to oxidation, sulfidation, blackening when damp, and long-term reflectivity decay. The optical performance of the film is stable over a long period of time and will not suffer from problems such as image dimming or contrast reduction due to the complex environment of the vehicle, thus ensuring the long-term high-definition imaging effect of the HUD. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the coating arrangement of a curved glass reflector. Figure 2 Schematic diagram of different areas tested for curved glass reflectors; Figure 3 for Figure 2 The reflectance curves for the three regions indicated in the figure; Figure 4 for Figure 2 The transmittance curves for the three regions indicated in the figure. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0023] Unless otherwise specified, the oxidant in the following examples refers to oxygen plasma.

[0024] In one embodiment, a method for preparing a long-lasting weather-resistant curved glass reflector includes the following steps: S1, Pretreatment: Take the hot-bent free-form glass after molding as the substrate, and perform multi-stage ultrasonic cleaning, drying and plasma surface activation treatment in sequence to remove surface oil and dust and improve the surface activity of the substrate. S2, Bottom Sealing Film Deposition: The pretreated hot-bent glass is deposited using the ALD process with trimethylaluminum as the precursor to form a dense aluminum oxide bottom film; Al2O3 with a refractive index of 1.55-1.65 is used for the bottom layer. S3, High-Reflectivity Optical Film Stack Deposition: Continuing with the ALD process, niobium pentoxide and silicon dioxide films are deposited alternately, ending with a niobium pentoxide film. Niobium pentoxide is deposited using niobium pentaethoxy as a precursor, while silicon dioxide is deposited using silane. Layer-by-layer growth is performed according to a preset number of cycles to construct a multilayer dielectric high-reflectivity film system. The high-refractive-index material is Nb₂O₅ (2.25-2.4), and the low-refractive-index material is SiO₂ (1.43-1.47). This all-dielectric high-reflectivity film system, employing alternating stacks of high and low refractive-index media, leverages the periodic optical matching between the high-refractive-index Nb₂O₅ and low-refractive-index SiO₂ materials to achieve high visible light reflectance and effective near-infrared cutoff, suppressing infrared backflow from sunlight and solving failure problems such as overheating, weathering degradation, and blackening from sulfidation in traditional metal films. Both niobium pentoxide and silicon dioxide are metal oxides. SiO2 is a covalent acid oxide, while Al2O3 is an amphoteric metal oxide. At room temperature, they are bonded by surface hydroxyl hydrogen bonds and weak van der Waals forces, with almost no ion interdiffusion. The bonding between niobium pentoxide and Al2O3 is better than that between SiO2 and Al2O3.

[0025] S4, Top-layer weather-resistant protective film deposition: Continuing to utilize the ALD process, using trimethylaluminum as a precursor, an aluminum oxide top-layer protective film is deposited; forming a pinhole-free, airtight protective structure that blocks the intrusion of water vapor, salt spray, humid heat, and corrosive media, significantly improving the high-temperature resistance, humid heat resistance, salt spray resistance, and aging resistance of the curved reflector, achieving automotive-grade long-term durability performance, with an average reflectivity of over 95% in the visible light (400-700nm) band at a 0-degree incident angle; S5, Post-treatment: After coating, the workpiece is vacuum annealed to release the internal stress of the film layer and then naturally cooled in the furnace to obtain a long-lasting weather-resistant curved glass reflector. This post-treatment is used to eliminate the internal deposition stress of the film layer, further improve the bonding strength between the film and the substrate and the overall density of the film layer, and avoid cracking and peeling of the film layer under long-term high and low temperature cycling conditions.

[0026] In a preferred embodiment, an ultrasonic cleaning process is used to sequentially clean the glass surface with pure water, anhydrous ethanol, and propofol in stages to remove dust, oil, mold release agent residue, and particulate impurities.

[0027] In a preferred embodiment, the drying temperature in step S1 is 80-100°C, and the drying time is 15-20 minutes.

[0028] In a preferred embodiment, the plasma surface activation treatment in step S1 is as follows: oxygen plasma is used to bombard the glass surface for 3 to 5 minutes to remove microscopic organic residues and increase the number of active sites on the glass surface, thereby effectively improving the adhesion between the subsequent film layer and the substrate and avoiding problems such as film peeling and detachment.

[0029] In a preferred embodiment, in step S2, the pre-treated hot-bent glass is processed using the ALD process within an ALD vacuum coating chamber, with the chamber's base vacuum level controlled to be ≤8×10⁻⁶. -4 Pa, the process temperature is stabilized at 160-180℃; the aluminum oxide base film is formed after 182 cycles, and the film thickness is 15-25nm; this step utilizes the self-limiting saturated growth characteristics of ALD to accurately fill the microscopic pinholes, microcracks and surface unevenness defects generated during the hot bending glass forming process, achieving full coverage of irregular curved surfaces without dead angles, solving the problem of film penetration failure caused by substrate defects in traditional coating processes, and providing a flat and dense adhesion substrate for subsequent optical films.

[0030] In a preferred embodiment, the alternating deposition of niobium pentoxide and silicon dioxide films in step S3 specifically involves: sequentially depositing the following layers on the aluminum oxide underlayer: A single-layer niobium pentoxide film was obtained after 417 cycles; A single-layer silica film was obtained by cycling 614 times. A single-layer niobium pentoxide film was obtained after 564 cycles; A single-layer silica film was obtained by cycling 641 times. A single-layer niobium pentoxide film was obtained after 531 cycles; A single-layer silica film was obtained by cycling 600 times. A single-layer niobium pentoxide film was obtained after 536 cycles; A single-layer silica film was obtained by cycling 656 times. A single-layer niobium pentoxide film was obtained after 610 cycles; A single-layer silica film was obtained by cycling 854 times. A single-layer niobium pentoxide film was obtained after 867 cycles; A single-layer silica film was obtained by cycling 728 times. A single-layer niobium pentoxide film was obtained after 672 cycles; A single-layer silica film was obtained by cycling 1001 times. A single-layer niobium pentoxide film was obtained after 755 cycles; A single-layer silica film was obtained by cycling 784 times. A single-layer niobium pentoxide film was obtained after 906 cycles; A single-layer silica film was obtained by cycling 947 times. A single-layer niobium pentoxide film was obtained through 467 cycles.

[0031] In a preferred embodiment, the thickness of the aluminum oxide top protective film is 10-80 nm, obtained by 1807 cycles.

[0032] In a preferred embodiment, in the ALD process in steps S2-S4, argon is used as both the carrier gas and the purge gas, and the adsorption, purge, and oxidant oxidation cycles are completed alternately by pulse.

[0033] In a preferred embodiment, the vacuum annealing in step S5 is performed by annealing at a constant temperature of 120°C for 30 minutes in a vacuum annealing chamber.

[0034] The long-lasting weather-resistant curved reflector glass prepared by the method of this invention has excellent uniformity of film thickness across the entire curved surface, with no defects such as thin edges, incomplete coating, or shadows. The image is free from color cast, rainbow patterns, and uneven brightness. It has no risk of metal film oxidation and sulfidation failure and can pass automotive-grade durability tests such as high and low temperature cycling from -40℃ to 105℃, 1500H damp heat aging, and salt spray corrosion. Its optical performance is stable over a long period of time, effectively solving the industry pain points of poor coating uniformity, weak weather resistance, and short service life of traditional HUD curved reflectors. It is suitable for the mass production application of high-end AR-HUDs. Example 1:

[0035] The first step is the pretreatment of the hot-bent glass substrate.

[0036] The hot-bent free-form glass after molding is used as the substrate. The glass is then cleaned in steps with pure water, anhydrous ethanol and isopropanol in sequence to remove dust, oil, mold release agent residue and particulate impurities from the glass surface. After cleaning, use dust-free hot air drying, with the drying temperature set at 80-100℃ and the drying time at 15-20 minutes. Subsequently, the glass surface is subjected to plasma activation treatment, which involves bombarding the glass surface with oxygen plasma for 3-5 minutes to remove microscopic organic residues and increase the number of active sites on the glass surface. This effectively improves the adhesion between the subsequent film layer and the substrate, preventing problems such as film peeling and detachment.

[0037] The pre-treated hot-bent glass is placed into the ALD vacuum coating chamber, and the background vacuum level of the chamber is controlled to be ≤8×10. - 4Pa, with the process temperature stabilized at 160-180℃, this step utilizes the self-limiting saturated growth characteristics of ALD to precisely fill the microscopic pinholes, microcracks and surface unevenness defects generated during the hot bending glass forming process, achieving full coverage of irregular curved surfaces without dead angles, completely solving the problem of film penetration failure caused by substrate defects in traditional coating processes, and providing a flat and dense adhesion substrate for subsequent optical films.

[0038] The second step is the deposition of the ALD bottom layer to seal the transition layer of the pores.

[0039] Trimethylaluminum (TMA) was used as the precursor, and argon was used as the carrier gas and purge gas. The gaseous precursor was introduced by alternating pulses, and the precursor underwent self-limiting saturated chemisorption with the substrate surface to form a monolayer. Between each pulse, excess reactants and byproducts were removed by purging with an inert gas, and an oxidant was introduced to react with the precursor to form a monolayer of aluminum oxide film. The first layer (1 film) was formed after 182 cycles, and the film thickness was controlled between 15 and 25 nm.

[0040] The third step is the deposition of an all-dielectric high-reflectivity optical film system. High-refractive-index dielectric films and low-refractive-index dielectric films are alternately deposited on the surface of the Al2O3 layer, ending with a high-refractive-index layer, forming a periodic all-dielectric high-reflectivity film system with alternating high and low refractive indices, without any metal functional layers.

[0041] The second layer (2-layer film) is deposited by alternately pulsed introduction of a gaseous precursor, using niobium pentaethoxy (Nb(OC2H5)5) as the precursor and argon as the carrier gas and purge gas. The precursor undergoes saturated chemical adsorption with the surface of the aluminum oxide film to form a monolayer. Between each pulse, excess reactants and byproducts are removed by purging with an inert gas, and an oxidant is introduced to react with the precursor to generate a monolayer niobium pentoxide film. This process is repeated 417 times to form the second layer (2-layer film).

[0042] The third layer (3-layer film) is deposited by using gaseous silane (SiH4) as a silicon-based precursor and argon as both the carrier gas and the purge gas. The gaseous silane is alternately pulsed through the precursor, which undergoes self-limited saturated chemisorption on the surface of the niobium pentoxide film to form a monoatom adsorption layer. Between each pulse, excess reactants and byproducts are removed by purging with an inert gas, and an oxidant is introduced to react with the precursor to form a monolayer silicon dioxide film. This process is repeated 614 times to form the third layer (3-layer film).

[0043] Depositing the fourth layer (4-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monolayer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer niobium pentoxide film. This process is repeated 564 times to obtain the fourth layer (4-layer film).

[0044] Depositing the fifth layer (5-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monolayer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer silicon dioxide film. This process is repeated 641 times to obtain the fifth layer (5-layer film).

[0045] Depositing the sixth layer (6-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monolayer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer niobium pentoxide film. The process is repeated 531 times to obtain the sixth layer (6-layer film).

[0046] Depositing the seventh layer (7-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer silicon dioxide film. This process is repeated 600 times to obtain the seventh layer (7-layer film).

[0047] Depositing the eighth layer (8-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monolayer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer niobium pentoxide film. This process is repeated 536 times to obtain the eighth layer (8-layer film).

[0048] Depositing the ninth layer (9-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer silicon dioxide film. This process is repeated 656 times to obtain the ninth layer (9-layer film).

[0049] Ten-layer (10-layer) coating: A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer niobium pentoxide film. This process is repeated 610 times to obtain the tenth 10-layer film.

[0050] The eleventh layer (11 film layer) is deposited by alternating pulses of gaseous precursor, which is saturated and adsorbed on the substrate surface to form a monoatomic layer; after purging with inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer silicon dioxide film. The process is repeated 854 times to obtain the eleventh layer (11 film layer).

[0051] Depositing the twelfth layer (12-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monolayer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer niobium pentoxide film. The process is repeated 867 times to obtain the twelfth layer.

[0052] Thirteenth layer (13 film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer silicon dioxide film. This process is repeated 728 times to obtain the thirteenth layer (13 film).

[0053] Depositing the fourteenth layer (14-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer niobium pentoxide film. This process is repeated 672 times to obtain the fourteenth layer (14-layer film).

[0054] The fifteenth layer (15-layer film) is deposited by alternating pulses of gaseous precursor, which is then saturated and adsorbed on the substrate surface to form a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer silicon dioxide film. This process is repeated 1001 times to obtain the fifteenth layer (15-layer film).

[0055] Depositing the sixteenth layer (16-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monolayer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer niobium pentoxide film. This process is repeated 755 times to obtain the sixteenth layer (16-layer film).

[0056] Depositing the seventeenth layer (17-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer silicon dioxide film. This process is repeated 784 times to obtain the seventeenth layer (17-layer film).

[0057] Depositing the eighteenth layer (18-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer niobium pentoxide film. This process is repeated 906 times to obtain the eighteenth layer (18-layer film).

[0058] Depositing the nineteenth layer (19-layer film): A gaseous precursor is alternately pulsed through the substrate surface to saturate and adsorb onto the substrate, forming a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer silicon dioxide film. This process is repeated 947 times to obtain the nineteenth layer (19-layer film).

[0059] The twentieth layer (20 film layer) is deposited by alternating pulses of gaseous precursor, which is saturated and adsorbed on the substrate surface to form a monoatomic layer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a monolayer of niobium pentoxide film. The process is repeated 467 times to obtain the twentieth 20 film layer.

[0060] The Nb₂O₅ / SiO₂ / Al₂O₃ films were all deposited using a plasma-assisted oxygen deposition (PEALD) process. The thickness deviation of each optical film layer prepared in this way is ≤1% across the entire curved surface. This all-dielectric film system can achieve high reflectivity in the 400–700 nm visible light band, with an average reflectivity ≥95%.

[0061] The fourth step is the deposition of a dense protective layer on the top layer of the ALD process. On the outermost layer of the all-dielectric high-reflectivity film system, a dense Al2O3 protective layer—the twenty-first layer (21 film layer)—is deposited using the ALD process: A gaseous precursor (trimethylaluminum) is alternately pulsed through the film, causing it to saturate and adsorb onto the surface of the all-dielectric high-reflectivity film system, forming a monolayer. After purging with an inert gas to remove impurities, an oxidant is introduced to react and generate a single-layer aluminum oxide film. This process is repeated 1807 times to obtain the twenty-first layer (21 film layer), with its thickness controlled at 70–80 nm. This protective layer continues the pinhole-free, dense film-forming characteristic of ALD, forming a closed protective structure that effectively blocks external moisture, salt spray, humid air, and corrosive media from entering the film system, preventing film layer delamination and interface oxidation, and significantly improving the reflector's resistance to humidity, salt spray, and UV aging.

[0062] Step 5: Vacuum annealing post-treatment. After coating, the glass is placed in a vacuum annealing chamber and annealed at a constant temperature of 120℃ for 30 minutes. It is then allowed to cool naturally to room temperature in the furnace to eliminate internal deposition stress, further improving the film-substrate bonding strength and overall film density. This prevents film cracking and peeling under long-term high and low temperature cycling conditions, resulting in a long-lasting weather-resistant curved glass reflector. A total of 21 film layers are deposited on the glass substrate; the layer arrangement is shown in [reference needed]. Figure 1 For thickness, please refer to Table 1.

[0063] The oxidant used in depositing the first to the 21st film layers was plasma oxygen. Argon was used as both the carrier gas and the purge gas. The high-refractive-index layer was deposited using niobium pentaethoxy (Nb(OC2H5)5) as a precursor by alternating pulses of gaseous precursors to deposit Nb2O5. The low-refractive-index layer was deposited using gaseous silane (SiH4) as a silicon-based precursor to deposit SiO2, and trimethylaluminum (TMA) as a precursor to deposit Al2O3.

[0064] Table 1 1 M 0.11 <![CDATA[Al2O3]]> 20 2 H 0.085 <![CDATA[Nb2O5]]> 35.41 3 L 0.13 <![CDATA[SiO2]]> 79.79 4 H 0.085 <![CDATA[Nb2O5]]> 47.97 5 L 0.13 <![CDATA[SiO2]]> 83.3 6 H 0.085 <![CDATA[Nb2O5]]> 45.16 7 L 0.13 <![CDATA[SiO2]]> 78.06 8 H 0.085 <![CDATA[Nb2O5]]> 45.59 9 L 0.13 <![CDATA[SiO2]]> 85.27 10 H 0.085 <![CDATA[Nb2O5]]> 51.83 11 L 0.13 <![CDATA[SiO2]]> 111.03 12 H 0.085 <![CDATA[Nb2O5]]> 73.72 13 L 0.13 <![CDATA[SiO2]]> 94.68 14 H 0.085 <![CDATA[Nb2O5]]> 57.15 15 L 0.13 <![CDATA[SiO2]]> 130.11 16 H 0.085 <![CDATA[Nb2O5]]> 64.16 17 L 0.13 <![CDATA[SiO2]]> 101.92 18 H 0.085 <![CDATA[Nb2O5]]> 77.02 19 L 0.13 <![CDATA[SiO2]]> 123.07 20 H 0.085 <![CDATA[Nb2O5]]> 39.67 21 M 0.11 <![CDATA[Al2O3]]> 70 The resulting long-lasting weather-resistant curved reflector glass exhibits excellent uniformity in the thickness of the entire curved surface coating, with no defects such as thin edges, incomplete coating, or shadows. The image is free from color cast, rainbow patterns, and uneven brightness. It eliminates the risk of metal film oxidation and sulfidation failure and can pass automotive-grade durability tests, including on-board high and low temperature cycling from -40℃ to 105℃, 1500H damp heat aging, and salt spray corrosion. Its optical performance remains stable over the long term, effectively solving the industry pain points of poor coating uniformity, weak weather resistance, and short service life of traditional HUD curved reflectors. It is suitable for high-end AR-HUD mass production applications.

[0065] The spectrum of the 300*180 long-lasting weather-resistant curved reflective glass was tested, and the location of the test area is as follows. Figure 2 As shown, Reflectance and transmittance were measured at three points: left, center, and right. The results are shown in the figure. Figure 3 It exhibits high reflectivity in the 400–700 nm visible light band, with an average reflectivity ≥95.5% and an average transmittance less than 4.5%. The absorption value can be roughly calculated using 1-reflection-transmission, with an absorption of less than 0.2%, which is far lower than that of conventional metal films.

[0066] This invention replaces the traditional plastic HUD with curved glass. Compared with the traditional magnetron sputtering metal-based reflective film process and conventional dielectric coating technology, it uses atomic layer deposition to prepare a multi-layer composite optical film system. Combined with an alternating stacked structure of high-refractive-index niobium pentoxide and low-refractive-index silicon dioxide, and an alumina sealing and protection structure, it has multiple technical advantages such as excellent uniformity of curved coating, strong weather resistance and reliability, and reduced HUD optomechanical thermal failure.

[0067] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a long-lasting weather-resistant curved glass reflector, characterized in that: Includes the following steps: S1， Pretreatment: Take the formed hot-bent free-form glass as the substrate and perform multi-stage ultrasonic cleaning, drying and plasma surface activation treatment in sequence; S2, Deposition of bottom sealing film: The pretreated hot-bent glass is deposited using the ALD process with trimethylaluminum as a precursor to form an aluminum oxide bottom film. S3, High-reflectivity optical film stack deposition: Continuing to use the ALD process, niobium pentoxide film and silicon dioxide film are deposited alternately, ending with niobium pentoxide film; wherein, niobium pentaethoxy is used as the precursor when depositing niobium pentoxide film, and silane is used as the precursor when depositing silicon dioxide film, and the film is grown layer by layer according to the preset number of cycles to construct a multilayer dielectric high-reflectivity film system. S4, Top layer weather-resistant protective film deposition: Continuing to use the ALD process, using trimethylaluminum as a precursor, deposit aluminum oxide top layer protective film; S5, Post-processing: After the coating is completed, the workpiece is vacuum annealed to release the internal stress of the film layer and then naturally cooled in the furnace to obtain a long-lasting weather-resistant curved glass reflector.

2. The preparation method according to claim 1, characterized in that: The multi-segment ultrasonic cleaning in step S1 includes: sequentially cleaning with pure water, anhydrous ethanol, and propofol using an ultrasonic cleaning process.

3. The preparation method according to claim 1, characterized in that: The drying temperature in step S1 is 80-100℃, and the drying time is 15-20 minutes.

4. The preparation method according to claim 1, characterized in that: The plasma surface activation treatment in step S1 is as follows: oxygen plasma bombardment for 3-5 minutes.

5. The preparation method according to claim 1, characterized in that: In step S2, the pre-treated hot-bent glass is processed using the ALD process within an ALD vacuum coating chamber, with the chamber's base vacuum level controlled to be ≤8×10⁻⁶. -4 Pa, the process temperature is stabilized at 160-180℃; the aluminum oxide bottom film is formed by 182 cycles, and the film thickness is 15-25nm.

6. The preparation method according to claim 1, characterized in that: The alternating deposition of niobium pentoxide and silicon dioxide films in step S3 specifically involves: sequentially depositing the following layers on the aluminum oxide underlayer: A single-layer niobium pentoxide film was obtained after 417 cycles; A single-layer silica film was obtained by cycling 614 times. A single-layer niobium pentoxide film was obtained after 564 cycles; A single-layer silica film was obtained by cycling 641 times. A single-layer niobium pentoxide film was obtained after 531 cycles; A single-layer silica film was obtained by cycling 600 times. A single-layer niobium pentoxide film was obtained after 536 cycles; A single-layer silica film was obtained by cycling 656 times. A single-layer niobium pentoxide film was obtained after 610 cycles; A single-layer silica film was obtained by cycling 854 times. A single-layer niobium pentoxide film was obtained after 867 cycles; A single-layer silica film was obtained by cycling 728 times. A single-layer niobium pentoxide film was obtained after 672 cycles; A single-layer silica film was obtained by cycling 1001 times. A single-layer niobium pentoxide film was obtained after 755 cycles; A single-layer silica film was obtained by cycling 784 times. A single-layer niobium pentoxide film was obtained after 906 cycles; A single-layer silica film was obtained by cycling 947 times. A single-layer niobium pentoxide film was obtained through 467 cycles.

7. The preparation method according to claim 1, characterized in that: The thickness of the aluminum oxide top protective film is 10-80 nm, obtained through 1807 cycles.

8. The preparation method according to claim 1, characterized in that: In the ALD process described in steps S2-S4, argon is used as both the carrier gas and the purging gas, and the adsorption, purging, and oxidation cycle of the oxidant are completed by alternating pulses.

9. The preparation method according to claim 1, characterized in that: The vacuum annealing described in step S5 is performed by annealing at a constant temperature of 120°C for 30 minutes inside a vacuum annealing chamber.

10. A long-lasting weather-resistant curved glass reflector prepared by any one of the preparation methods described in claims 1-9.

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