Method for constructing waterproof film layer on surface of optical window component and optical equipment

Abstract

The invention relates to the technical field of optical window surface functional coatings, in particular to a method for constructing a waterproof film layer on the surface of an optical window component and optical equipment. The method for constructing the waterproof film layer on the surface of the optical window component comprises the following steps: providing the optical window component; preprocessing the surface of the optical window component to improve the surface energy of the optical window component; providing a temperature and humidity dual response type polymer coating; and carrying out wet-temperature induced spin coating on the surface of the pretreated optical window component to form a film. The waterproof film layer constructed by the invention has excellent waterproof, light-transmitting and environment-adaptive performances, and is suitable for application scenes such as vehicle-mounted, security and industrial cameras.

Description

Technical Field

[0001] This invention relates to the field of functional coating technology for optical window surfaces, and particularly to a method and optical device for constructing a waterproof film layer on the surface of an optical window component. Background Technology

[0002] With the rapid development of applications such as intelligent monitoring, vehicle-mounted assisted driving, drone imaging, and maritime monitoring, camera modules are increasingly used in complex outdoor environments. However, prolonged exposure to conditions such as high humidity, rain, dust, salt spray, and alternating hot and cold temperatures can easily cause water droplets, fog condensation, and dirt buildup on the surface of camera lenses, severely affecting image clarity and equipment stability.

[0003] In existing technologies, waterproofing and fog prevention are often achieved through traditional sealing ring structures, hydrophobic coating spraying, or surface heating. However, these methods have many shortcomings: structural seals are prone to aging and deformation, ordinary hydrophobic coatings are prone to wear and failure, heating methods are energy-intensive and have long delays, and most protective measures only have a single function and lack the ability to adapt to environmental changes.

[0004] Furthermore, while some nano-coatings possess hydrophobic properties, they suffer from complex fabrication processes, poor film adhesion, and insufficient optical transmittance, making it difficult to meet the dual requirements of high-definition camera lenses for both optical performance and structural reliability. Therefore, there is an urgent need to develop a functional film structure that is structurally stable, easy to fabricate, adaptable to varying humid and hot environments, and possesses both superhydrophobicity and high light transmittance, in order to achieve long-term clear imaging and reliable protection for camera lenses in complex environments. Summary of the Invention

[0005] To address the problem of poor environmental adaptability of optical window surface coatings in the prior art, this invention provides a method and optical device for constructing a waterproof membrane layer on the surface of an optical window component.

[0006] In a first aspect, the present invention provides a method for constructing a waterproof membrane layer on the surface of an optical window component, comprising the following steps: Provide optical window components; The surface of the optical window component is pretreated to increase the surface energy of the optical window component to more than 50 mN / m. Offers temperature and humidity responsive polymer coatings; A film is formed by wet-temperature induced spin coating on the surface of the pre-treated optical window component.

[0007] In one embodiment of the present invention, the pretreatment includes oxygen plasma treatment and / or ultraviolet ozone treatment.

[0008] In one embodiment of the present invention, the oxygen plasma treatment has a power of 50-100 W, a treatment time of 30-60 s, and a gas flow rate of 25-35 sccm, preferably 30 sccm.

[0009] In one embodiment of the present invention, the ultraviolet wavelengths of the ultraviolet ozone treatment are 185nm and 254nm, and the power density is 5-25mW / cm². 2 The irradiation time is 10-15 minutes.

[0010] In one embodiment of the present invention, the raw materials for preparing the temperature and humidity responsive polymer coating include: polymer components, organic solvents and phase separation inducers; The polymer components include: 35wt%-55wt% polyurethane, 30wt%-50wt% polydimethylsiloxane, and 15wt%-30wt% polyN-isopropylacrylamide; Preferably, the mass ratio of the polyurethane, polydimethylsiloxane, and poly(N-isopropylacrylamide) is 4:4:2.

[0011] In one embodiment of the present invention, the organic solvent is a mixed solvent of dimethylformamide (DMF) and tetrahydrofuran (THF); Preferably, the volume ratio of dimethylformamide (DMF) to tetrahydrofuran (THF) is 1:1.

[0012] In one embodiment of the present invention, the polymer component further includes a phase separation inducing agent; Preferably, the phase separation inducing agent is anhydrous ethanol and / or ultrapure water; Preferably, the phase separation inducing agent accounts for 2 vol%-5 vol% of the total volume of the temperature and humidity responsive polymer coating.

[0013] In one embodiment of the present invention, the conditions for humidity-temperature induction are: an environment with a humidity of 60%-80% and a temperature of 25-35°C.

[0014] In one embodiment of the present invention, the spin coating method is as follows: under temperature and humidity induced conditions, the coating is spin-coated onto the surface of the optical window component at a speed of 500 rpm for 3 seconds, and then the speed is increased to 3000 rpm for a second spin coating for 60 seconds.

[0015] In a second aspect, the present invention provides an optical device, the optical device including an optical window component, the surface of which is provided with a waterproof membrane layer constructed by the method described above.

[0016] Based on the above, compared with the prior art, the present invention constructs a polymer biomimetic film layer with a composite structure of micron-level protrusions and nano-level roughness on the surface of optical window components through a phase separation mechanism induced by humidity and temperature, which significantly improves the superhydrophobic properties and self-cleaning ability of the coating.

[0017] Other features and beneficial effects of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other beneficial effects of the invention can be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Unless otherwise specified, the positional relationships shown in the drawings in the following description are based on the direction in which the components are drawn in the figure.

[0019] Figure 1 A schematic diagram of the micron-sized protrusion structure on the surface of the waterproof membrane layer; Figure 2 A schematic diagram of the nanoscale rough undulation structure on the surface of the protrusion structure of the waterproof membrane layer; Figure 3 A schematic diagram of the micro-nano dual-scale structure of the waterproof membrane; Figure 4 Comparison of SEM images of the samples before and after the salt spray corrosion test. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of 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, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that all terms used in this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and should not be construed as limiting the invention; it should be further understood that the terms used in this invention should be understood to have the same meaning as those in the context of this specification and in the relevant field, and should not be understood in an idealized or overly formal sense, except as expressly defined in this invention.

[0022] Those skilled in the art will understand that the order in which the steps are written in the various implementations or embodiments does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps in this application can be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps 1 and 2, it means that the method may include steps 1 and 2 performed sequentially, or it may include steps 2 and 1 performed sequentially. For example, if the method may also include step 3, it means that step 3 can be added to the method in any order. For example, the method may include steps 1, 2, and 3, or it may include steps 1, 3, and 2, or it may include steps 3, 1, and 2, etc.

[0023] The term "PC" used in this article refers to a polymer material, whose chemical name is polycarbonate. The term "PMMA" as used in this article refers to a polymer material whose chemical name is polymethyl methacrylate (or plexiglass). One embodiment of the present invention provides a method for constructing a waterproof film layer on the surface of an optical window component. Includes the following steps: Step 1: Provide the optical window component; In some embodiments of the present invention, the optical window component may serve as a transparent interface between the device and the external environment, such as a camera glass lens, a PC optical cover plate, or a PMMA window.

[0024] Step 2: Pre-treat the surface of the optical window component to increase the surface energy of the optical window component to above 50 mN / m; In this embodiment, the optical window component is a camera glass lens. The substrate (glass lens) to be coated is pretreated to improve the adhesion performance of the polymer film. In some preferred embodiments of the present invention, the pretreatment includes oxygen plasma treatment and / or ultraviolet ozone treatment; wherein, taking oxygen plasma treatment as an example, the oxygen plasma treatment includes placing the substrate (glass lens) in a processing device and applying it at a power of 50W-100W with a gas flow rate of 25-35... The oxygen plasma treatment is carried out in an environment with an sccm concentration for 30-60 seconds; for example, the power of the oxygen plasma treatment is 50W, 55W, 60W, 65W, 70W, 75W, 80W, 85W, 90W, 95W, 100W, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable; for example, the gas flow rate is 25sccm, 26sccm, 27sccm, 28sccm, 29sccm, 30sccm, 31sccm, 32sccm, 33sccm, 34sccm, 35sccm or any value between them; and for example, the treatment time of the oxygen plasma treatment is 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds or any value between them; Alternatively, taking ultraviolet ozone treatment as an example, the ultraviolet ozone treatment includes placing the substrate (glass lens) in a treatment device, using ultraviolet light wavelengths of 185nm and 254nm, and subjecting it to UV-O3 irradiation for 10-15 minutes to remove surface organic contaminants and activate functional groups. After treatment, immediate drying and purging should be performed to ensure the surface is free of dust, oil, and water, which is beneficial for the uniformity and stability of subsequent film formation. For example, the irradiation time for the ultraviolet ozone treatment can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, or any value between them. Through the above pretreatment, the surface free energy of the camera lens surface is increased, raising the surface free energy of the substrate to 40 mN / m or even higher than 50 mN / m, thereby enhancing the adhesion and coating uniformity of the polymer coating.

[0025] Based on this, the present invention provides the following embodiments for illustration.

[0026] Example 1 An optical window component is provided, which is a protective glass for the front window of a camera (Al2O3 high-hardness glass) with dimensions of 20mm×20mm×0.7mm; The initial surface condition of the protective glass for the front window of the camera is: visually clean, but with invisible organic residues (such as grease, fingerprints, and volatile impurities). The initial water contact angle of the protective glass in the front window of the camera is 78°. The initial surface free energy of the protective glass for the front window of the camera is approximately 36 mN / m.

[0027] The protective glass of the camera's front window is subjected to oxygen plasma treatment. The treatment equipment is a 13.56MHz radio frequency oxygen plasma cleaner with the following parameters: oxygen flow rate of 30 sccm, power of 70W, chamber pressure of 20Pa, and treatment time of 45 seconds. After oxygen plasma treatment, purge with high-purity nitrogen for 30 seconds and let stand in a drying oven for 3 minutes before use.

[0028] Example 2 The same optical window component as in Embodiment 1 is provided.

[0029] The protective glass of the camera front window was subjected to ultraviolet ozone treatment. The treatment equipment was a high-intensity mercury lamp UV-O3 cleaner. The parameters were set as follows: ultraviolet wavelengths of 185 nm and 254 nm, irradiation time of 12 minutes, and distance between the sample and the lamp tube of 2 cm. After the ultraviolet ozone treatment is completed, allow it to cool naturally to room temperature before use.

[0030] Example 3 An optical window component is provided, wherein the optical window component is a PC (polycarbonate) lens with dimensions of 20mm × 20mm × 1mm; The initial water contact angle of the PC (polycarbonate) lens is 84°; The initial surface free energy of the PC (polycarbonate) lens is approximately 33 mN / m.

[0031] The PC (polycarbonate) lens was subjected to oxygen plasma treatment. The treatment equipment was a 13.56MHz radio frequency oxygen plasma cleaner with the following parameters: oxygen flow rate of 30 sccm, power of 60W, chamber pressure of 20Pa, and treatment time of 30 seconds. After oxygen plasma treatment, purge with high-purity nitrogen for 30 seconds and let stand in a drying oven for 3 minutes before use.

[0032] Example 4 An optical window component is provided, wherein the optical window component is PMMA (acrylic) and its dimensions are 25mm × 25mm × 1.5mm; The initial water contact angle of the PMMA (acrylic) is 76°; The initial surface free energy of the PMMA (acrylic) is approximately 36 mN / m.

[0033] The PMMA (acrylic) was subjected to ultraviolet ozone treatment using a high-intensity mercury lamp UV-O3 cleaner. The parameters were set as follows: ultraviolet wavelengths of 185 nm and 254 nm, irradiation time of 10 minutes, and distance between the sample and the lamp tube of 2 cm. After the ultraviolet ozone treatment is completed, allow it to cool naturally to room temperature before use.

[0034] The changes in water contact angle were compared between the optical window components of Examples 1 and 2, which were pretreated in different ways respectively. The results are shown in Table 1. Table 1. Effects of different surface treatments on improving contact angle and hydrophilicity

[0035] Contact angle measurements were performed on the optical window components of Examples 1 and 2, which were made of different materials and under different treatments (measured using water (surface tension γ = 72.8 mN / m) and diiodomethane (surface tension γ = 50.8 mN / m) respectively), and free energy estimation tables (Owens-Wendt method) were also performed. The structures are shown in Table 2. Table 2 Contact angle and surface free energy under different materials and treatment methods

[0036] Based on the above embodiments, it can be seen that oxygen plasma treatment is superior to UV-O3 in terms of processing efficiency and processing depth, and is especially suitable for the activation treatment of smooth, inert surfaces. If there are strict requirements for the long-term adhesion of the coating (such as outdoor cameras, automotive lenses), oxygen plasma treatment should be preferred, and the coating operation should be completed as soon as possible after treatment to avoid surface energy decay.

[0037] Step 3: Provide a temperature and humidity responsive polymer coating; In this embodiment, the raw materials for preparing the temperature and humidity responsive polymer coating include: polymer components, organic solvents, and optional phase separation inducing agents; The organic solvent, serving as a dispersion medium, is capable of dissolving the polymer components. In one embodiment of the invention, the organic solvent is selected from at least one of dimethylformamide (DMF) and tetrahydrofuran (THF). Further, the organic solvent is a mixture of dimethylformamide (DMF) and tetrahydrofuran (THF); in a preferred embodiment of the invention, the volume ratio of dimethylformamide (DMF) to tetrahydrofuran (THF) is 1:1.

[0038] Specifically, the phase separation inducer is capable of initiating the self-assembly of the membrane microstructure, and may be, for example, anhydrous ethanol and / or ultrapure water, wherein the phase separation inducer accounts for 2 vol%-5 vol% of the total volume percentage of the temperature and humidity responsive polymer coating. For example, 2 vol%, 3 vol%, 4 vol%, 5 vol%, or any value between them; Specifically, in the polymer component, polyurethane (PU) serves as the matrix framework, providing mechanical strength and thermosetting crosslinking sites. The weight percentage of the polyurethane (PU) is 35wt%-55wt%. In some specific embodiments, the weight percentage of polyurethane (PU) is 35wt%, 36wt%, 37wt%, 38wt%, 39wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49wt%, 50wt%, 51wt%, 52wt%, 53wt%, 54wt%, 55wt%, or any value between them. If the proportion is too low, the mechanical properties will be insufficient and the structure will be prone to cracking, while if it is too high, the responsiveness of the coating will be sacrificed. Specifically, in the polymer component, polydimethylsiloxane (PDMS) has low surface energy segments, constructing a hydrophobic interface and imparting flexibility; more specifically, the PDMS molecular backbone is -Si-O-Si-, highly compliant, and the terminal methyl groups impart extremely low surface energy (19). The PDMS content (mN / m) facilitates the formation of a hydrophobic top layer. During spin coating, PDMS automatically migrates to the film surface, forming a hydrophobic shell, enhancing the surface lotus leaf effect. Furthermore, PDMS, being a flexible chain segment, can alleviate the tensile stress between PU and PNIPAm, improving film flexibility and thermal cycling stability. The weight percentage of polydimethylsiloxane (PDMS) is 30wt%-50wt%. In some specific embodiments, the weight percentage of PDMS is 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt%, 38wt%, 39wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49wt%, 50wt%, or any value between them. If the percentage is too low, the hydrophobic layer will be incomplete; if it is too high, the structure will be loose and adhesion will decrease. Specifically, in the polymer component, poly(N-isopropylacrylamide) (PNI-PAm) serves as the main responsive component, exhibiting structural shrinkage / expansion in response to temperature and humidity changes. The weight percentage of poly(N-isopropylacrylamide) (PNI-PAm) is 15wt%-30wt%. In some specific embodiments, the weight percentage of poly(N-isopropylacrylamide) (PNI-PAm) is 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, or any value between them. If the proportion is too low, its responsiveness is weakened; conversely, if the proportion is too high, phase separation is severe, leading to increased structural instability.

[0039] In a preferred embodiment of the present invention, the mass ratio of polyurethane, polydimethylsiloxane, and polyN-isopropylacrylamide is 4:4:2. The micro-nano structure formed under this ratio is the most uniform, with a contact angle of up to 157.8° and a slip angle of less than 2.5°.

[0040] In one specific embodiment of the present invention, a method for preparing a temperature and humidity-responsive polymer coating is provided, comprising the following steps: The polymer components are added to an organic solvent according to the specified ratio and mixed to obtain the final product. Preferably, the phase separation inducer is added after mixing with the organic solvent; In another preferred embodiment of the present invention, the mixed coating is filtered through a filter membrane to obtain a clear, uniform, and responsive coating with suitable viscosity.

[0041] Based on this, the present invention provides the following embodiments for illustration.

[0042] Example 5 This embodiment provides a method for preparing a temperature and humidity-responsive polymer coating, including the following steps: Solvent preparation: Prepare a 45 mL mixture of DMF and THF in a 1:1 volume ratio and place it in a clean 250 mL three-necked flask. Weighing and adding materials: Weigh 2.0g of PU, 2.0g of PDMS and 1.0g of PNIPAm using a precision electronic balance; slowly add them in batches to the mixed solvent and stir magnetically to ensure thorough dispersion; Add phase separation inducer: Accurately measure 2.5 mL of anhydrous ethanol with a pipette and slowly add it dropwise to the stirred system. Continue stirring for 30 minutes to ensure uniform distribution. Dissolve by stirring: Stir continuously for more than 12 hours on a 50℃ constant temperature magnetic stirrer, and observe until the solution is clear, free of flocculation and bubbles; Filtration and impurity removal: Vacuum filtration is performed using a 0.22μm polytetrafluoroethylene (PTFE) membrane to remove any undissolved impurities or aggregates that may be present, resulting in a coating.

[0043] Step 4: Apply a wet-temperature induced spin coating to the pretreated optical window component surface.

[0044] In this embodiment, the temperature and humidity responsive polymer coating is uniformly applied to the pretreated substrate (optical window component) surface using a spin coating method. Two-stage spin coating is performed in a controlled environment with a relative humidity of 60%-80% and a temperature of 25-35℃. The two-stage spin coating method is as follows: under temperature and humidity induced conditions, the coating is spin-coated onto the surface of the optical window component at a speed of 500 rpm for 3 seconds, and then the speed is increased to 3000 rpm for a second spin coating for 60 seconds.

[0045] The process involves two main stages: First, a pre-spreading process is performed at 500 rpm for 3 seconds to form an initial uniform liquid film, effectively eliminating surface tension gradients and suppressing the "coffee ring effect" and edge aggregation that occur during subsequent high-speed spin coating. Second, the main film formation process is completed at 3000 rpm for 60 seconds. Rapid shearing stretches the polymer segments, enhancing inter-chain orientation. Simultaneously, rapid solvent evaporation combined with controlled humidity and temperature triggers phase separation between PNIPAm and PU, inducing micro / nano structures. Furthermore, maintaining humidity at 60%-80% allows water vapor to penetrate and form a liquid-liquid interface, promoting the low surface energy assembly of PDMS segments and ultimately forming a lotus leaf-like micron-sized protrusions and nano-roughness structure. Specifically, in a high-humidity environment, water vapor diffuses into the spin-coated liquid film, enhancing local segment incompatibility and forming a liquid-liquid phase separation (LLPS) mechanism. Combined with rapid solvent evaporation, the film surface self-assembles to form micron-sized protrusions and nano-sized textures, ultimately solidifying into a dual-scale structure with lotus leaf-like biomimetic functionality.

[0046] During spin coating, due to the synergistic effect of rapid solvent evaporation, water vapor penetration, and heterogeneous separation of polymer chain segments, micron-scale protrusions and nano-scale rough undulations spontaneously form on the film surface, creating a lotus leaf-like micro-nano dual-scale structure that endows the coating with excellent hydrophobic and self-cleaning properties.

[0047] It should be noted that the micron-scale boss structure is as follows: Figure 1As shown, these nanoscale roughness undulations, typically 1-20 μm in diameter and a few micrometers in height, resemble tiny hills evenly distributed across the surface. Their function is to elevate the bottom of the water droplet, reducing the solid-liquid contact area; and to form an air buffer layer, allowing the water droplet to roll spherically without spreading out. These nanoscale roughness undulations are like... Figure 2 As shown, the surface protrusions are further covered with small protrusions or rough textures at the 50-500nm level, like a layer of "fine sand" or "fluff" covering the surface of micron-sized hills. Its function is to further reduce the solid-liquid contact area (higher air content); and to increase the water droplet contact angle, making it easier for water droplets to roll off and carry away dust (self-cleaning effect). The micro / nano dual-scale structure is as follows... Figure 3 As shown, the micron-scale structure is the "large framework," while the nano-scale structure is the "refinement and modification," and the two combined create a dual roughness. Its advantages include: a large contact angle (>150°), making the water droplet almost spherical; a small slip angle (<5°), causing the water droplet to roll away with a gentle shake; and waterproof, anti-fog, and self-cleaning capabilities.

[0048] However, the adverse effects of using other methods to replace spin coating (such as spraying or scraping) are as follows: Specifically, spraying can result in uneven atomization and unstable thickness, making it difficult to accurately control the phase separation time window and leading to incomplete structures; scraping can result in excessive thickness, insufficient solvent evaporation, and difficulty in stimulating chain segment rearrangement and microstructure self-assembly; dip coating can result in excessive liquid residue, incomplete phase separation of PNIPAm, and collapsed microstructures; thus, the film roughness decreases, the contact angle is less than 140°, the structural repeatability is poor, and the functional performance is unstable.

[0049] Therefore, the two-stage spin coating process and temperature and humidity induction conditions used in this application are optimal conditions derived from a precise matching of the thermodynamic phase behavior, segment migration, and surface assembly characteristics of the material system. Compared to spraying and scraping methods, this method can stably form micro / nano biomimetic structures, endowing the coating with excellent superhydrophobicity, self-cleaning properties, and environmental responsiveness. PDMS in the formulation is not used as an antifoaming agent, but rather as a core hydrophobic component.

[0050] Step 5: After film formation, perform low-temperature heat curing and shaping.

[0051] After film formation, the sample is placed on a constant-temperature hot plate at 80°C for heat curing for 30-60 minutes. During the heat treatment, chemical cross-linking and physical stabilization occur within the coating, while the micro-nano structure is shaped and cured, resulting in a polymer waterproof membrane with long-term stability. In a preferred embodiment of the invention, to further ensure that the biomimetic structure does not collapse, a slow heating strategy can be adopted (e.g., holding at 60°C for 10 minutes and then raising to 80°C) to maintain good morphological fidelity during the shaping process. Based on this, the present invention provides the following embodiments for illustration.

[0052] Example 6 This embodiment provides a method for preparing a waterproof membrane layer, including the following steps: Provides an optical window component pretreated (ultraviolet ozone) from Example 2; A coating is provided, said coating being derived from the temperature and humidity dual-responsive polymeric coating prepared in Example 5; Adjust the ambient temperature to 30℃ and the humidity to 70%RH; Use a micropipette to take 0.3 mL of the coating and drop it onto the center of the optical window component; perform temperature and humidity induced two-stage spin coating: in the first (pre-spreading) stage, spin the coating onto the surface at 500 rpm for 3 seconds; in the second (main spin) stage, spin the coating at 3000 rpm for 60 seconds; After spin coating, allow it to stand naturally for 1 minute to allow residual solvent to evaporate. The sample was transferred to a constant temperature hot plate at 80°C for heat curing treatment for 45 minutes.

[0053] Membrane performance characterization: After curing, the surface properties of the film are tested. A contact angle meter is used to evaluate the water droplet contact angle, with a target value greater than 140° and a slip angle less than 5°, to confirm its superhydrophobic properties. A spectral transmittance meter can be used to measure the film's transmittance in the 400-800 nm wavelength range, with a target value of fi90%. For further enhancement of waterproof durability, a thin layer of fluorosilane can be deposited on the film surface or a dust-repellent coating can be applied. Ultimately, a nanofunctional film with a thickness controlled between 500 nm and 2 μm is formed, exhibiting intelligent responsiveness, biomimetic structure, and excellent optical properties.

[0054] Hydrophobicity test (using a contact angle meter) Testing instrument: KRUSS DSA100; Water droplet volume: 5 μL, dropped into the center of the membrane layer. Optical transmittance test (using a UV-Vis spectrophotometer) Instrument model: Agilent Cary 5000, test band: 400-800nm; The test results are shown in the table below: Table 3 Results of surface wettability and stability tests

[0055] As can be seen from Table 3, the waterproof membrane layer prepared in Example 6 has superhydrophobicity and excellent self-cleaning properties.

[0056] Table 4. Optical transmittance test results in the visible light band.

[0057] The consistency and structural stability of the waterproof membrane layer were verified: The film thickness and contact angle were measured at three different points (center, edge, and diagonal), and the deviation was controlled within ±5%, indicating that the spin coating film formation process has good uniformity. The contact angle decreased by less than 2° after 72 h of high temperature and high humidity aging test (60℃, 90% RH), indicating that the structure is well stabilized.

[0058] The test results are shown in the table below: Table 5. Test results of consistency and structural stability of the waterproof membrane.

[0059] Example 7 Example 6 provides a spin-coated film that has not undergone low-temperature thermosetting. The sample was first placed on a 60°C hot plate for 10 minutes to preheat, and then the hot plate was heated to 80°C at a rate of 2°C / min, and kept at that temperature for 30 minutes.

[0060] The waterproof membrane layer prepared in Example 7 was tested, and the results are shown in the table below: Table 6 Results of surface wettability and stability tests

[0061] As can be seen from Table 6, the waterproof membrane layer prepared in Example 7 is superhydrophobic and has excellent self-cleaning properties, while also exhibiting low adhesion and good stability.

[0062] The waterproof membranes prepared in Examples 6 and 7 were then tested, and the test results are shown in the table below: Table 7. Effects of different curing methods on the performance of waterproof membranes

[0063] Therefore, it is evident that employing a phased, slow-heating curing method allows for the gradual shaping of micro / nano structures, resulting in higher surface morphology retention. Specifically, the slow-heating curing strategy (60℃→80℃) effectively suppresses structural collapse and cracking caused by excessively rapid chain rearrangement in the film layer without increasing the total processing time. This ensures the integrity and long-lasting superhydrophobic properties of the micro / nano biomimetic structure, making it recommended for applications such as camera optical components or other scenarios requiring high morphology fidelity.

[0064] Optionally, the method also includes fluorosilane vapor deposition on the surface of the cured and shaped waterproof membrane; the vapor deposition material can be 1H, 1H, 2H, 2H-Perfluorooctyltriethoxysilane (PFOTES), etc.; the vapor deposition method is vapor phase deposition.

[0065] Example 8 Provide the sample obtained in Example 7; Fluorosilane vapor deposition is performed; the vapor deposition method is vapor phase deposition, for example, vapor deposition is performed at 90°C for 1 hour.

[0066] After fluorosilane vapor deposition, the contact angle of the waterproof membrane increased from 151.3° to 157.8°, and the slip angle decreased from 3.6° to 2.1°. A wiping resistance test (10 wipes with a wet cloth) showed that the hydrophobicity of the sample without vapor deposition decreased by 10%, while the hydrophobicity of the sample after fluorosilane vapor deposition did not decrease significantly.

[0067] The samples prepared in Example 8 were subjected to environmental stability tests such as salt spray corrosion, sand erosion, and thermal cycling. The test standard for the fume corrosion was ASTM B117, and the test conditions were: temperature 35℃, salt solution 5% NaCl, and spraying time continuous for 72 hours. The test results are shown in the table below: Table 8 Comparison of sample performance before and after salt spray corrosion test

[0068] As shown in Table 6, the contact angle decreased by 3.2° (retention rate 98%) and the slip angle increased by 0.3° after the test. Furthermore, no structural collapse or dissolution was observed under SEM. Figure 4 As shown.

[0069] The test standard for sand and dust erosion is based on ISO 20567-1 (abrasion resistance) and a customized sand and dust simulation chamber. The test conditions are: wind speed of 20 m / s, particle size of 50-200 μm (quartz sand and dust), erosion time of 15 minutes, and incident angle of 45°. Table 9 Evaluation of Sample Effluent and Self-Healing Performance

[0070] As can be seen from Table 7, the waterproof membrane layer of the present invention has self-healing ability and good damage resistance.

[0071] The test standard for the thermal cycling is GB / T 2423.22-2002 (Environmental Test), which simulates the alternation of day and night and the four seasons. The test cycle parameters are: cycle temperature range: -30℃ to 60℃, cycle period: 4 hours, and total number of cycles: 30.

[0072] Table 10 Comparison of performance retention of samples before and after cyclic fatigue testing.

[0073] As shown in Table 8, the contact angle decreased by 7.6° (retention rate 95.2%) before and after the test, the slip angle increased slightly by 1.4°, the transmittance did not change significantly, only decreased by 1.4%, and there was no microstructural damage from the surface microstructure. It can be seen that the waterproof membrane layer of the present invention has excellent thermal stability and mechanical fatigue resistance.

[0074] Comparative Example 1 The difference between Comparative Example 1 and Example 8 is that no pretreatment was performed.

[0075] Therefore, contact angle initial value, salt spray corrosion, thermal cycling, contact angle change after sand and dust erosion, and retention rate were tested for Example 8 and Comparative Example 1. The results are shown in the table below: Table 11

[0076] As shown in Table 11, the surface treatment not only improved the initial contact angle but also effectively slowed down the functional degradation. Simultaneously, the contact angle retention rate increased from 87.3% to 94.6%, providing support for actual stability under humid / corrosive environments. Furthermore, the surface structure integrity was higher, verifying the anchoring effect of surface polar functional groups on micro / nano structures. Therefore, the plasma or ultraviolet ozone surface treatment used in this application not only improved film adhesion but also significantly enhanced the structural stability and functional retention rate of the coating under harsh environments such as salt spray corrosion, thermal cycling, and sand erosion, resulting in enhanced interfacial coupling for the waterproof membrane.

[0077] Specifically, the plasma or ultraviolet ozone treatment technology applied to the surface of optical window components in this invention, in its specific application scenarios, not only achieves conventional adhesion improvement but also produces other technical effects, enhancing the overall performance stability and functional performance of the coating structure: (1) Inducing the formation of surface polar groups enhances the sensitivity of wet-temperature induced phase separation. After treatment with oxygen plasma or UV-O3, polar functional groups such as -OH, -C=O, and -COOH are introduced into the surface of glass or polymer substrates. These groups significantly increase the surface energy and form hydrogen-bonded micro-region interfaces with the hydrophilic segments of PNIPAm in the coating. This interface stability plays a template guiding role in the subsequent wet-temperature induced phase separation process, which helps to build the uniform and orderly structure of biomimetic micro-nano structures and avoids local collapse of the film or "dry edge effect". (2) Improve the conformity of micro and nano structures When untreated surfaces are spin-coated with responsive polymer coatings, the low surface tension gradient leads to uneven film thickness and easy edge retraction during the film formation stage, resulting in local collapse of the final lotus leaf-like structure. However, the surface-treated samples show improved wetting properties, which significantly increases the integrity of the micro / nano protrusion array formation (by approximately 15-20%). (3) Suppressing structural warping and microcracks In the subsequent low-temperature thermosetting process, the treated surface can effectively release the shrinkage stress of the film layer and reduce the concentration of internal stress during the drying process, thereby significantly reducing the probability of film layer cracking, edge opening and warping, and improving the consistency and yield of the preparation process. (4) Enhance the weather resistance and impact stability of the self-cleaning membrane. The surface-treated film exhibits stronger interfacial stability and higher contact angle retention in salt spray corrosion, thermal cycling, and sand erosion tests (see comparative data in the examples). This indicates that the interfacial polarity generated by the surface treatment enhances the overall mechanical coupling and chemical stability of the coating, resulting in practical performance improvement.

[0078] In summary, the waterproof membrane layer provided in this application has the following advantages: First, the surface water contact angle can reach over 150° and the slip angle is less than 5°, enabling water droplets to roll off quickly and preventing rainwater retention and pollution deposition; Second, the coating has temperature and humidity response characteristics, which can dynamically respond to dew point changes and water vapor condensation, significantly reducing the risk of lens fogging and improving image clarity; Third, the coating thickness is controllable (500nm to 2μm), and the transmittance can reach over 90% in the 400-800nm ​​visible light range, which is suitable for the imaging requirements of high-definition cameras; Fourth, it retains superhydrophobic properties after salt spray corrosion, thermal cycling, and sandstorm erosion tests, and has good outdoor applicability and surface durability; Fifth, the coating system composition is adjustable, adaptable to various substrates (glass, PC, PMMA, etc.) and large-scale spin coating / spraying processes, and has the foundation for industrialization and promotion.

[0079] In another embodiment of the present invention, the present invention provides an optical device, which can be a monitoring device, a ranging device, a temperature detection device, a visual inspection device, etc. For example, in vehicle camera systems, it can be used for modules such as autonomous driving, parking assistance, driving recording, and environmental perception, improving imaging clarity and sensor stability in rainy and foggy weather; in security monitoring equipment, it can be used for lens waterproofing and anti-fog protection of outdoor surveillance cameras, smart city road monitoring, and park monitoring equipment, extending the service life of the equipment; in drone and aerial imaging systems, it can be used for lightweight self-cleaning protection of camera modules in flight, especially ensuring imaging quality in humid, sea fog, and high wind speed environments; in industrial visual inspection systems, it can be used for machine vision lens protection in heavily polluted environments such as ports, factories, and mining areas, improving image acquisition stability and system reliability; in marine and underwater camera systems, it can be used for lens anti-salt fog and waterproof membrane design for ships, buoys, underwater robots, etc., enhancing adaptability to marine environments; and in consumer-grade optical modules, it can be extended to the surface functional coating design of small optical systems such as smart doorbells, action cameras, and mobile phone external lenses, etc.

[0080] The optical device includes an optical window component, the surface of which is provided with a waterproof membrane layer constructed by the method described above.

[0081] Furthermore, the film-forming method and coating system of the present invention can also be extended to other fields requiring the construction of functional thin films with hydrophobicity, antifouling, light transmission and microstructure shaping, such as solar glass, self-cleaning windows, and sensor light-transmitting covers, etc., and have good versatility and industrial application prospects.

[0082] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0083] Although this document frequently uses terms such as optical window components, pretreatment, surface energy, and temperature and humidity responsive polymer coatings, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention. The terms "first," "second," etc. (if present), in the specification, claims, and accompanying drawings of the embodiments of the invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for constructing a waterproof membrane layer on the surface of an optical window component, characterized in that, Includes the following steps: Provide optical window components; The surface of the optical window component is pretreated to improve its surface energy; Offers temperature and humidity responsive polymer coatings; A film is formed by wet-temperature induced spin coating on the surface of the pre-treated optical window component.

2. The method for constructing a waterproof membrane layer on the surface of an optical window component according to claim 1, characterized in that, The pretreatment includes oxygen plasma treatment and / or ultraviolet ozone treatment.

3. The method for constructing a waterproof membrane layer on the surface of an optical window component according to claim 2, characterized in that, The oxygen plasma treatment has a power of 50-100W, a treatment time of 30-60s, and a gas flow rate of 25-35 sccm, preferably 30 sccm.

4. The method for constructing a waterproof membrane layer on the surface of an optical window component according to claim 2, characterized in that, The ultraviolet ozone treatment uses ultraviolet wavelengths of 185nm and 254nm, with a power density of 5-25mW / cm². 2 The irradiation time is 10-15 minutes.

5. The method for constructing a waterproof membrane layer on the surface of an optical window component according to claim 1, characterized in that, The raw materials for preparing the temperature and humidity responsive polymer coating include: polymer components and organic solvents; The polymer components include: 35wt%-55wt% polyurethane, 30wt%-50wt% polydimethylsiloxane, and 15wt%-30wt% polyN-isopropylacrylamide; Preferably, the mass ratio of the polyurethane, polydimethylsiloxane, and poly(N-isopropylacrylamide) is 4:4:

2.

6. The method for constructing a waterproof membrane layer on the surface of an optical window component according to claim 5, characterized in that, The organic solvent is a mixture of dimethylformamide and tetrahydrofuran; Preferably, the volume ratio of dimethylformamide to tetrahydrofuran is 1:

1.

7. The method for constructing a waterproof membrane layer on the surface of an optical window component according to claim 5, characterized in that, The polymeric component also includes a phase separation inducing agent; Preferably, the phase separation inducing agent is anhydrous ethanol and / or ultrapure water; Preferably, the phase separation inducing agent accounts for 2 vol%-5 vol% of the total volume of the temperature and humidity responsive polymer coating.

8. The method for constructing a waterproof membrane layer on the surface of an optical window component according to claim 1, characterized in that, The conditions for humidity-temperature induction are: an environment with a humidity of 60%-80% and a temperature of 25-35℃.

9. The method for constructing a waterproof membrane layer on the surface of an optical window component according to claim 1, characterized in that, The spin coating method is as follows: under temperature and humidity induced conditions, the coating is spin-coated onto the surface of the optical window component at a speed of 500 rpm for 3 seconds, and then the speed is increased to 3000 rpm for a second spin coating for 60 seconds.

10. An optical device, characterized in that, The optical device includes an optical window component, the surface of which is provided with a waterproof membrane layer constructed by any one of claims 1-9.

Images