A multilayer optical functional coating, its preparation method and application

Abstract

This invention belongs to the field of optical materials technology and discloses a multilayer optical functional coating, its preparation method, and its application. The multilayer optical functional coating comprises, from the inside out, an anti-reflective layer, an anti-glare layer, and an anti-fingerprint layer sequentially disposed on the surface of a transparent substrate. The anti-glare layer is prepared from low-refractive-index sol and hollow silica microspheres, with the hollow silica microspheres dispersed in the low-refractive-index sol. This invention introduces an anti-glare layer containing hollow silica microspheres onto the anti-reflective layer and controls the content of the hollow silica microspheres to limit the gloss of the anti-glare layer within a reasonable range. This achieves low reflection and anti-glare performance while maintaining good display clarity. Furthermore, an anti-fingerprint layer is superimposed on its surface to improve surface wettability.

Description

Technical Field

[0001] This invention belongs to the field of optical materials technology, specifically relating to a multilayer optical functional coating, its preparation method, and its application. Background Technology

[0002] With the rapid development of display technology and human-computer interaction devices, display panels, touch screens, and various optical windows have placed more stringent demands on surface optical performance and actual user experience. In high-definition displays, automotive displays, and outdoor environments with strong sunlight, an ideal optical surface not only needs to have extremely high light transmittance to ensure display brightness and energy efficiency, but also must simultaneously possess low reflectivity and low glare characteristics to minimize ambient light interference, improve visual comfort, and alleviate eye fatigue. Furthermore, in environments with frequent touch usage, surfaces are easily contaminated by fingerprints, grease, and dust. This not only damages the aesthetic appearance of the device but also causes image blurring and decreased optical performance due to light scattering. Therefore, durable fingerprint resistance and easy cleaning performance have become standard requirements for modern optical components.

[0003] In existing technologies, an anti-reflective layer, an anti-glare layer, and an anti-fingerprint layer are typically deposited sequentially on the surface of a transparent substrate to achieve various optical and surface functions. However, in practical applications, it has been found that improving anti-glare (AG) performance often relies on introducing a strong light-scattering structure on the coating surface, such as by increasing the content of inorganic particles or enhancing surface roughness to suppress specular reflection. While this approach can effectively reduce glare, it can easily lead to a significant decrease in coating gloss, resulting in problems such as a grayish appearance and reduced clarity in the display image.

[0004] Furthermore, when the gloss level of the anti-glare layer is too high, even if an anti-fingerprint layer is further formed on its surface, it is difficult to achieve a balance between low glare and high display clarity, thus affecting the overall visual effect and user experience. Therefore, how to achieve synergistic control of gloss, haze, and transmission performance through the rational design of the anti-glare layer on the basis of the anti-reflective structure, and how to superimpose an anti-fingerprint layer on it without damaging the existing optical performance, remains a technical problem that urgently needs to be solved in the current technology.

[0005] Regarding anti-fingerprint (AF) performance, the current mainstream approach is to modify it by coating with low surface energy materials. However, these films are often thin and have limited functionality. When the anti-fingerprint layer is superimposed on the underlying anti-reflective or anti-glare structure, the high coupling degree of process parameters between the multilayer film system often leads to a mismatch in refractive index between the layers, which in turn destroys the original optical interference design. This makes it difficult to achieve efficient synergy between high light transmittance, low glare, and anti-fingerprint performance within the same coating system. Summary of the Invention

[0006] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a multilayer optical functional coating, its preparation method, and its application. By introducing an anti-glare layer containing nano-hollow silica microspheres on top of an anti-reflection layer and controlling the content of nano-hollow silica microspheres, the gloss of the anti-glare layer is limited to a reasonable range, thereby achieving low reflection and anti-glare performance while maintaining good display clarity. Furthermore, an anti-fingerprint layer is superimposed on its surface to improve surface wettability.

[0007] To address the aforementioned technical problems, a first aspect of the present invention provides a multilayer optical functional coating comprising an anti-reflective layer, an anti-glare layer, and an anti-fingerprint layer disposed sequentially from the inside out on the surface of a transparent substrate; the anti-glare layer is prepared from low-refractive-index sol and nano-hollow silica microspheres, wherein the nano-hollow silica microspheres are dispersed in the low-refractive-index sol.

[0008] Specifically, the multilayer optical functional coating of the present invention includes an anti-reflection layer, an anti-glare layer, and an anti-fingerprint layer, wherein: the anti-reflection layer is used to reduce interface reflection on the surface of a transparent substrate; the anti-glare layer is disposed on the surface of the anti-reflection layer, which is constructed by introducing a certain amount of nano-hollow silica microspheres into a low-refractive-index film-forming sol system to construct a micro-nano composite structure with adjustable light scattering intensity, thereby achieving synergistic control of the gloss, haze, and transmission performance of the anti-glare layer; the anti-fingerprint layer has low surface energy, which can effectively improve surface wettability. Therefore, by combining the gloss control of the anti-glare layer with the anti-reflection and anti-fingerprint layers, the present invention achieves a balance of low reflection, low glare, and good anti-fingerprint performance without relying on excessive surface roughness, making it suitable for display and touch optical interfaces.

[0009] In some embodiments of the present invention, the refractive index of the low-refractive-index sol is 1.20-1.45.

[0010] In some embodiments of the present invention, the solid content of the nano-air silica microsphere dispersion is 15-25 wt%; and the mass percentage of the nano-hollow silica microsphere dispersion in the anti-glare layer is 1-10 wt%.

[0011] In some embodiments of the present invention, the mass percentage of the nano-hollow silica microsphere dispersion in the anti-glare layer is 5-9 wt%.

[0012] In some embodiments of the present invention, the mass percentage of the nano-hollow silica microsphere dispersion in the anti-glare layer is 6-8 wt%.

[0013] In some embodiments of the present invention, the particle size of the hollow silica nanospheres is 50-80 nm.

[0014] In some embodiments of the present invention, the preparation process of the low refractive index sol includes the following steps: (1) Mix silicate compounds with a portion of alcohol solvent, add acidic aqueous solution, and carry out hydrolysis reaction; (2) Add organosilicon compounds to the hydrolysis product in step (1) to perform hydrophobic modification and obtain modified sol; (3) After pre-dispersing the nano-silica sol with the remaining alcohol solvent, add it to the modified sol and mix; then add the film-forming resin and leveling agent to obtain the low refractive index sol.

[0015] In some embodiments of the present invention, the silicate compound is selected from at least one of tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMOS), and tetrapropyl orthosilicate; preferably tetraethyl orthosilicate.

[0016] In some embodiments of the present invention, the organosilicon compound is selected from at least one of methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), ethyltrimethoxysilane, ethyltriethoxysilane, and phenyltrimethoxysilane; preferably methyltrimethoxysilane.

[0017] In some embodiments of the present invention, the film-forming resin is selected from at least one of acrylate resins, epoxy resins, polyurethane resins, and silicone resins; preferably, it is an acrylate film-forming resin.

[0018] In some embodiments of the present invention, the acidic aqueous solution is selected from at least one aqueous solution of nitric acid, hydrochloric acid, sulfuric acid, acetic acid, and phosphoric acid.

[0019] In some embodiments of the present invention, the concentration of the acidic aqueous solution is 5-10%.

[0020] In some embodiments of the present invention, the leveling agent is selected from at least one of polyether-modified polydimethylsiloxane, fluorocarbon surfactant, and polyacrylate leveling agent, such as BYK-306.

[0021] In some embodiments of the present invention, the alcohol solvent is selected from at least one of methanol, ethanol, isopropanol (IPA), n-butanol, and ethylene glycol monomethyl ether.

[0022] In some embodiments of the present invention, the nano-silica sol is selected from colloidal silica in which the dispersion medium is alcohol, such as LUDOX®AM colloidal silica.

[0023] In some embodiments of the present invention, the raw materials for preparing the low refractive index sol include, by weight: 12-18 parts of silicate ester compound, 4.8-7.2 parts of organosilicon compound, 12-18 parts of nano-silica sol, 2-3 parts of film-forming resin, 0.2-0.3 parts of leveling agent, 7.2-10.8 parts of alcohol solvent, and 1.8-2.7 parts of acidic aqueous solution.

[0024] In some embodiments of the present invention, in steps (1) and (3), the volume ratio of the alcohol solvent is 1:(0.5-1).

[0025] In some embodiments of the present invention, the antireflective layer has a single-layer, double-layer, or triple-layer structure, wherein: the single-layer structure is a low-refractive-index layer, the double-layer structure includes a medium-refractive-index layer and a low-refractive-index layer, and the triple-layer structure includes a medium-refractive-index layer, a high-refractive-index layer, and a low-refractive-index layer; preferably, the antireflective layer has a triple-layer structure, which includes a medium-refractive-index layer, a high-refractive-index layer, and a low-refractive-index layer from the inside out.

[0026] In some embodiments of the present invention, the refractive index of the low refractive index layer is 1.20-1.45, the refractive index of the medium refractive index layer is 1.50-1.75, and the refractive index of the high refractive index layer is 1.80-2.30.

[0027] In some embodiments of the present invention, the raw material for preparing the low refractive index layer is the low refractive index sol.

[0028] In some embodiments of the present invention, the raw materials for preparing the intermediate refractive index layer include nano-titanium oxide sol and nano-silica sol.

[0029] In some embodiments of the present invention, the mass ratio of the nano-titanium oxide sol to the nano-silica sol is (1-50):1.

[0030] In some embodiments of the present invention, the raw materials for preparing the high refractive index layer are selected from at least one of TiO2 sol, ZrO2 sol, Nb2O5 sol, Ta2O5 sol, and SnO2 sol.

[0031] In some embodiments of the present invention, the gloss of the anti-glare layer is 60-100 GU under an incident angle of 60°.

[0032] In some embodiments of the present invention, the raw materials for preparing the anti-fingerprint layer include polydimethylsiloxane and organic solvents.

[0033] In some embodiments of the present invention, the organic solvent includes n-hexane.

[0034] In some embodiments of the present invention, the volume ratio of the polydimethylsiloxane to the organic solvent is 1:(5-20).

[0035] In some embodiments of the present invention, the volume ratio of the polydimethylsiloxane to the organic solvent is 1:(5-15).

[0036] In some embodiments of the present invention, the volume ratio of the polydimethylsiloxane to the organic solvent is 1:(8-12).

[0037] In some embodiments of the present invention, the transparent substrate is PET or PC, which have excellent mechanical properties, electrical insulation properties and moisture barrier properties.

[0038] A second aspect of the present invention provides a method for preparing the multilayer optical functional coating described in the first aspect of the present invention, comprising the following steps: 1) Coat the surface of a transparent substrate with an anti-reflective sol to form an anti-reflective layer; 2) A low-refractive-index sol containing nano-hollow silica microspheres is coated onto the surface of the anti-reflection layer to form an anti-glare layer; 3) An anti-fingerprint solution is dipped into the surface of the anti-glare layer to form an anti-fingerprint layer, thus obtaining the multilayer optical functional coating.

[0039] The third aspect of the present invention provides the application of the multilayer optical functional coating described in the first aspect of the present invention in display panels, touch interfaces, optical elements or transparent devices.

[0040] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages: (1) This invention constructs an anti-glare layer containing nano-hollow silica microspheres on top of an anti-reflection layer, and uses the content of hollow silica microspheres as a key control parameter. This allows the anti-glare layer to achieve effective light scattering and reduce specular reflection, while its gloss, haze and transmission performance can be limited within a reasonable range that balances anti-glare effect and display clarity. This avoids the problem of excessive reliance on surface roughening in existing anti-glare technologies, which leads to a significant decrease in gloss.

[0041] (2) The present invention also forms an anti-fingerprint layer on the surface of the anti-glare layer. As an ultra-thin surface modification layer, the anti-fingerprint layer mainly improves the wetting behavior of the coating surface and gives it good anti-fingerprint and easy-to-clean properties, while having little impact on the microstructure and optical properties of the anti-glare layer.

[0042] (3) The multilayer optical functional coating provided by the present invention achieves a comprehensive effect of controllable gloss, good display clarity and stable anti-fingerprint performance while maintaining low reflectivity and good anti-glare performance. It has good process controllability and application value. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of the multilayer optical functional coating of the present invention; Figure 2 This is a schematic diagram of the anti-reflection layer of the multilayer optical functional coating of the present invention; Figure 3 This is a schematic diagram of the fabrication process of the multilayer optical functional coating of the present invention; Figure 4 The transmittance and reflectance spectra of the single-layer antireflection layer prepared in Example 1 of the present invention; Figure 5 The transmittance and reflectance spectra of the double-layer antireflection layer prepared in Example 2 of the present invention; Figure 6 This is a comparison chart of the transmittance of the anti-glare layers prepared in Examples 4-7 of the present invention; Figure 7 The diagram shows the contact angle variation of the multilayer optical functional coatings prepared in Examples 8-19 of this invention. Detailed Implementation

[0044] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the invention. Furthermore, all raw materials mentioned below, unless otherwise specified, are commercially available products; all process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0045] Some of the raw materials used in the following examples and comparative examples are as follows: Tetraethyl orthosilicate (TEOS): T819507, Shanghai Maclean Biochemical Technology Co., Ltd.; Methyltrimethoxysilane (MTMS): T743030, Shanghai Maclean Biochemical Technology Co., Ltd.; LUDOX® AM Colloidal Silica: J01940, Shanghai Mairui Biochemical Technology Co., Ltd.; Nano-hollow silica microspheres: particle size range 50-80nm, Ningbo Fengmin New Material Technology Co., Ltd. n-Hexane: H109654, Shanghai Aladdin Biochemical Technology Co., Ltd.; Polydimethylsiloxane (PDMS): H431357, Shanghai Aladdin Biochemical Technology Co., Ltd.; PET film: 200μm, Dongguan Zuming New Materials Co., Ltd.

[0046] like Figure 1 As shown, the multilayer optical functional coating of the present invention includes an anti-reflective layer 102, an anti-glare layer 103, and an anti-fingerprint layer 104 disposed from the inside out on the surface of a transparent substrate 101. See also... Figure 2 In parts (a)-(c), the anti-reflective layer 102 can be a single-layer structure, which is a low-refractive-index layer 102-1; or a double-layer structure, which includes a medium-refractive-index layer 102-2 and a low-refractive-index layer 102-1 from the inside to the outside; or a triple-layer structure, which includes a medium-refractive-index layer 102-2, a high-refractive-index layer 102-3 and a low-refractive-index layer 102-1 from the inside to the outside.

[0047] Figure 3 This is a schematic diagram of the fabrication process of the multilayer optical functional coating of the present invention, including the following steps: 1. Synthesis of low refractive index solution: Silicate ester compounds are mixed with a portion of alcohol solvent, and acidic aqueous solution is slowly added dropwise under continuous stirring. After the addition is complete, stirring is continued to carry out the hydrolysis reaction. Then, organosilicon compounds are added in portions, and hydrophobic modification is carried out under continuous stirring to obtain a modified sol. The nano-silica sol is then pre-dispersed with the remaining alcohol solvent and slowly added to the modified sol under stirring. The mixture is stirred until homogeneous to obtain a mixed solution. Finally, film-forming resin and leveling agent are added to the mixed solution, and the system is stirred until it is homogeneous and stable to obtain a low refractive index sol.

[0048] 2. Preparation of anti-glare (AG) solution and anti-fingerprint solution: Add nano-hollow silica microsphere dispersion to low refractive index sol and disperse evenly to obtain anti-glare solution; dilute polydimethylsiloxane with organic solvent and stir evenly to obtain anti-fingerprint solution.

[0049] 3. Substrate cleaning and coating process: First, the transparent substrate is ultrasonically cleaned, then an anti-reflective solution and an anti-glare solution are spin-coated onto its surface in sequence, followed by an anti-fingerprint solution. The substrate is then dried in the air to form an anti-fingerprint layer.

[0050] 4. Final structure and function: An anti-reflective layer, an anti-glare layer, and an anti-fingerprint layer are formed sequentially from the inside to the outside on the surface of the transparent substrate. These layers have the characteristics of low reflectivity, light scattering, and high contact angle, respectively, and have anti-reflective, anti-glare, and anti-fingerprint functions.

[0051] Example 1 A method for preparing a single-layer antireflective layer includes the following steps: (1) Preparation of low refractive index sol: 7.5 g of TEOS and 2.5 g of isopropanol were added to a clean, anhydrous, and dry beaker. Under continuous stirring, 0.375 g of an acidic aqueous solution consisting of 4.68% HNO3 and 0.75 g of deionized water was slowly added dropwise. After the addition was complete, stirring was continued to carry out the hydrolysis reaction. Then, 3 g of MTMS was added in portions, and stirring was continued for 15-30 min to obtain the modified sol. In another beaker, 7.5 g of LUDOX®AM colloidal silica was pre-dispersed with 2 g of IPA. Then, the dispersed solution was slowly added dropwise to the modified sol and mixed evenly. Subsequently, 1.25 g of functional acrylic modified polymer and 0.125 g of BYK-306 were added, and stirring was continued for 30 min to obtain the low refractive index sol (refractive index 1.37).

[0052] (2) Preparation of a single anti-reflective layer: A PET film with a size of 30×50×0.2mm is used as a transparent substrate and cleaned with an ultrasonic cleaner for 3 minutes. The low refractive index sol prepared in step (1) is spin-coated on the surface of the transparent substrate to form a single anti-reflective layer.

[0053] Example 2 A method for preparing a double-layer anti-reflective layer includes the following steps: A PET film with dimensions of 30×50×0.2mm was used as a transparent substrate and cleaned with an ultrasonic cleaner for 3 minutes. A mixture of silica sol and titanium dioxide sol (refractive index 1.72) with a mass ratio of 1:6 and a low refractive index sol prepared in Example 1 were spin-coated sequentially on the surface of the transparent substrate to form a double anti-reflective layer.

[0054] Example 3 A method for preparing a three-layer anti-reflective layer includes the following steps: A PET film with dimensions of 30×50×0.2mm was used as a transparent substrate and cleaned with an ultrasonic cleaner for 3 minutes. A mixture of silica sol and titanium dioxide sol (refractive index 1.72), titanium dioxide sol (refractive index 1.90), and low refractive index sol prepared in Example 1 were sequentially spin-coated onto the surface of the transparent substrate in a mass ratio of 1:6 to form a three-layer anti-reflection layer.

[0055] Example 4 A method for preparing an anti-glare layer includes the following steps: (1) Preparation of anti-glare solution: First, nano-hollow silica microspheres were dispersed in isopropanol to obtain a nano-hollow silica microsphere dispersion (solid content of 20wt%); then, it was placed on a magnetic stirrer and stirred at 500rpm for 10min; then, the low refractive index sol prepared in Example 1 was taken, and the nano-hollow silica microsphere dispersion was added during continuous stirring, and stirring was continued to obtain the anti-glare solution. Among them, the mass ratio of the nano-hollow silica microsphere dispersion in the anti-glare solution was 1%.

[0056] (2) Preparation of anti-glare layer: spin-coating the anti-glare solution obtained in step (1) onto the surface of the double anti-reflective layer prepared in Example 2 to form an anti-glare layer.

[0057] Example 5 The only difference between Example 5 and Example 4 is that the mass percentage of the nano-hollow silica microsphere dispersion in the anti-glare solution is 4%.

[0058] Example 6 The only difference between Example 6 and Example 4 is that the mass percentage of the nano-hollow silica microsphere dispersion in the anti-glare solution is 7%.

[0059] Example 7 The only difference between Example 7 and Example 4 is that the mass percentage of the nano-hollow silica microsphere dispersion in the anti-glare solution is 10%.

[0060] Example 8 A method for preparing a multilayer optical functional coating includes the following steps: (1) Preparation of anti-fingerprint solution: First, prepare a certain amount of n-hexane as a diluent and PDMS as the solute to be diluted. Using a high-precision pipette, measure 5 mL of PDMS and slowly pour it into a clean reagent bottle, then dilute it with n-hexane. The volume ratio of PDMS to n-hexane is 1:5. At the same time, use a clean glass rod to initially stir the solution while adding n-hexane to promote the initial mixing of PDMS and n-hexane. Then, place the reagent bottle on a magnetic stirrer and start stirring until it is observed that PDMS has completely dissolved in n-hexane, forming a homogeneous PDMS / n-hexane solution, thus obtaining the anti-fingerprint solution.

[0061] (2) Preparation of multilayer optical functional coating: The anti-glare layer prepared in Example 4 is vertically immersed in the anti-fingerprint solution obtained in step (1) for 2 minutes, and slowly pulled out to air dry to form an anti-fingerprint layer, thus preparing a multilayer optical functional coating.

[0062] Example 9 The only difference between Example 9 and Example 8 is that the volume ratio of PDMS to n-hexane in the anti-fingerprint solution is 1:10.

[0063] Example 10 The only difference between Example 10 and Example 8 is that the volume ratio of PDMS to n-hexane in the anti-fingerprint solution is 1:20.

[0064] Example 11 The only difference between Example 11 and Example 8 is that, in the preparation process of the multilayer optical functional coating, the anti-glare layer prepared in Example 4 is replaced with the anti-glare layer prepared in Example 5.

[0065] Example 12 The only difference between Example 12 and Example 11 is that the volume ratio of PDMS to n-hexane in the anti-fingerprint solution is 1:10.

[0066] Example 13 The only difference between Example 13 and Example 11 is that the volume ratio of PDMS to n-hexane in the anti-fingerprint solution is 1:20.

[0067] Example 14 The only difference between Example 14 and Example 8 is that, in the preparation process of the multilayer optical functional coating, the anti-glare layer prepared in Example 4 is replaced with the anti-glare layer prepared in Example 6.

[0068] Example 15 The only difference between Example 15 and Example 14 is that the volume ratio of PDMS to n-hexane in the anti-fingerprint solution is 1:10.

[0069] Example 16 The only difference between Example 16 and Example 14 is that the volume ratio of PDMS to n-hexane in the anti-fingerprint solution is 1:20.

[0070] Example 17 The only difference between Example 17 and Example 8 is that, in the preparation process of the multilayer optical functional coating, the anti-glare layer prepared in Example 4 is replaced with the anti-glare layer prepared in Example 7.

[0071] Example 18 The only difference between Example 18 and Example 17 is that the volume ratio of PDMS to n-hexane in the anti-fingerprint solution is 1:10.

[0072] Example 19 The only difference between Example 19 and Example 17 is that the volume ratio of PDMS to n-hexane in the anti-fingerprint solution is 1:20.

[0073] Comparative Example 1 The only difference between Comparative Example 1 and Example 6 is that the hollow silica microspheres in the anti-glare solution are replaced with an equal amount of solid silica microspheres of the same particle size.

[0074] Comparative Example 2 The only difference between Comparative Example 2 and Example 6 is that the nano-hollow silica microspheres in the anti-glare solution were replaced with an equal amount of hollow glass microspheres (particle size 15-30 μm).

[0075] Comparative Example 3 The only difference between Comparative Example 3 and Example 8 is that the anti-fingerprint solution is undiluted pure PDMS.

[0076] Performance testing 1. Anti-glare performance The optical properties of the thin film samples prepared in Examples 1-7 and Comparative Examples 1-2 were tested using a UV-vis-NIR spectrometer to examine the optical properties of the anti-glare layer with different particles at 550 nm. The results are shown in Table 1.

[0077] Table 1:

[0078] As shown in Table 1, without the addition of microspheres, the gloss of the coating remains above 150 GU regardless of whether a single-layer, double-layer, or triple-layer anti-reflection structure is used, and the haze value is extremely low. Although the surface reflectivity is significantly reduced by increasing the number of film layers using the principle of light wave interference, the specular reflection characteristics of the surface are still significant, and it cannot effectively diffusely reflect and scatter ambient light. This indicates that the anti-glare function cannot be achieved by relying solely on the anti-reflection film layer itself, and scattering particles must be introduced to construct a surface with optical roughness.

[0079] Further comparison of the data from Example 6 with Comparative Examples 1 and 2 reveals that the microstructure and material of the microspheres have a decisive influence on optical performance. Compared to the solid silica microspheres of Comparative Example 1, the hollow silica microspheres used in Example 6 exhibit higher transmittance (85.75%) and lower reflectance (2.87%) while achieving better anti-glare performance. This is mainly attributed to the air cavities within the hollow microspheres effectively reducing the equivalent refractive index of the particles, resulting in a better match between the refractive index of the microspheres and the matrix resin. This significantly reduces backscattering loss of light within the coating, thereby improving light energy utilization. The hollow glass microspheres used in Comparative Example 2, due to their large micron-sized particle size, produced a severe scattering effect in the coating, causing the haze to surge to 12.89%, which seriously affected the clarity of the display. Furthermore, their excessive size disrupted the optical interference conditions of the anti-reflection layer, resulting in a deterioration of the reflectivity to 4.88%. This confirms that nanoscale hollow silica microspheres have better overall optical performance than solid microspheres and large-particle-size glass microspheres.

[0080] Optimization studies on the amount of hollow silica microspheres added showed that Example 6 achieved the best balance between high transmittance, low reflectance, and suitable anti-glare effect. It is noteworthy that although Example 5 achieved the lowest gloss (44.2 GU), its reflectance abnormally increased to 3.82%, and its haze reached 10.72%, indicating that the distribution of microspheres at this concentration may have disrupted the destructive stability of the film's optical interference, leading to a deterioration in display quality. In contrast, Example 6 controlled the reflectance at a lower level of 2.87%, maintained a high transmittance of 85.75%, and a moderate haze of 6.72%. Its gloss of 96.8 GU corresponds to a high-definition anti-glare effect, effectively suppressing glare while maximizing the preservation of image contrast and clarity. Therefore, 7 wt% is the optimal addition ratio of hollow silica microspheres.

[0081] 2. Anti-fingerprint performance The optical properties of the thin film samples prepared in Examples 8-19 were tested using a UV-Vis-NIR spectrometer to examine the optical properties of different optical functional coatings at 550 nm. The results are shown in Table 2. Static water contact angles were measured using a contact angle meter. Three points were randomly selected for each sample group, and the average value was taken. The results are shown in Table 2. Figure 7 As shown in Table 3.

[0082] Table 2:

[0083] Table 3:

[0084] From Table 2-3 and Figure 7The droplet morphology analysis shown indicates that the static water contact angle of the thin film samples prepared in Examples 8-19 remained above 111°, indicating that the coating prepared by this invention has excellent hydrophobic properties. Comparison of different process parameters revealed that the dilution factor of the anti-fingerprint layer (PDMS) and the microsphere content in the anti-glare layer have a significant synergistic regulatory effect on surface wetting performance. As the PDMS dilution factor increased from 5 to 20 times, the contact angle showed a trend of first increasing and then slightly decreasing. A 10-fold dilution typically yielded better hydrophobic effects because the thickness of the low surface energy molecular layer formed at this concentration was more suitable.

[0085] The increased microsphere content introduces a micro-nano rough structure, further enhancing the surface hydrophobicity. In Example 15, when the amount of hollow silica microspheres added was 7% and the anti-fingerprint layer was diluted 10 times, the static water contact angle reached a maximum of 124.295°. This indicates that at this ratio, the surface roughness constructed by the 7% concentration of microspheres achieved optimal matching with the coverage of the low surface energy material. Combined with the transmittance and reflectance data in Table 2, Example 15 not only exhibits excellent optical performance but also demonstrates the best performance in hydrophobic and anti-fingerprint properties, indicating that the multilayer optical functional coating of the present invention can simultaneously possess high transmittance, low reflectance, anti-glare, and easy-to-clean characteristics.

[0086] For those skilled in the art, several simple deductions or substitutions can be made without departing from the inventive concept, without requiring creative effort. Therefore, any simple improvements made to this invention by those skilled in the art based on the disclosure of this invention should be within the scope of protection of this invention. The above embodiments are preferred embodiments of this invention, and all processes similar to this invention and equivalent changes should fall within the scope of protection of this invention.

Claims

1. A multilayer optical functional coating, characterized in that, It includes an anti-reflective layer, an anti-glare layer, and an anti-fingerprint layer, which are sequentially disposed on the surface of a transparent substrate from the inside out; the raw materials for preparing the anti-glare layer include a low refractive index sol and a dispersion of hollow silica microspheres, and the hollow silica microspheres are dispersed in the low refractive index sol.

2. The multilayer optical functional coating according to claim 1, characterized in that, The solid content of the nano-air silica microsphere dispersion is 15-25 wt%; in the anti-glare layer, the mass percentage of the nano-hollow silica microsphere dispersion is 1-10 wt%.

3. The multilayer optical functional coating according to claim 1, characterized in that, The preparation process of the low refractive index sol includes the following steps: (1) Mix silicate compounds with a portion of alcohol solvent, add acidic aqueous solution, and carry out hydrolysis reaction; (2) Add organosilicon compounds to the hydrolysis product in step (1) to perform hydrophobic modification and obtain modified sol; (3) After pre-dispersing the nano-silica sol with the remaining alcohol solvent, add it to the modified sol and mix; then add the film-forming resin and leveling agent to obtain the low refractive index sol.

4. The multilayer optical functional coating according to claim 3, characterized in that, The silicate ester compound is selected from at least one of tetraethyl orthosilicate, tetramethyl orthosilicate, tetrapropyl orthosilicate, and tetrabutyl orthosilicate. And / or, the organosilicon compound is selected from at least one of methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and phenyltrimethoxysilane; And / or, the film-forming resin is selected from at least one of acrylate resins, epoxy resins, polyurethane resins, and silicone resins; And / or, the acidic aqueous solution is selected from at least one aqueous solution of nitric acid, hydrochloric acid, sulfuric acid, acetic acid, and phosphoric acid; And / or, the leveling agent is selected from at least one of polyether-modified polydimethylsiloxane, fluorocarbon surfactant, and polyacrylate leveling agent; And / or, the alcohol solvent is selected from at least one of methanol, ethanol, isopropanol, n-butanol, and ethylene glycol monomethyl ether.

5. The multilayer optical functional coating according to claim 3 or 4, characterized in that, The raw materials for preparing the low refractive index sol include, by weight: 12-18 parts of silicate ester compound, 4.8-7.2 parts of organosilicon compound, 12-18 parts of nano-silica sol, 2-3 parts of film-forming resin, 0.2-0.3 parts of leveling agent, 7.2-10.8 parts of alcohol solvent, and 1.8-2.7 parts of acidic aqueous solution.

6. The multilayer optical functional coating according to claim 1, characterized in that, The anti-reflective layer has a single-layer, double-layer, or triple-layer structure, wherein: the single-layer structure is a low-refractive-index layer, the double-layer structure includes a medium-refractive-index layer and a low-refractive-index layer, and the triple-layer structure includes a medium-refractive-index layer, a high-refractive-index layer, and a low-refractive-index layer. The low refractive index layer has a refractive index of 1.20-1.45, the medium refractive index layer has a refractive index of 1.50-1.75, and the high refractive index layer has a refractive index of 1.80-2.

30.

7. The multilayer optical functional coating according to claim 1, characterized in that, The anti-glare layer has a gloss level of 60-100 GU at a 60° incident angle.

8. The multilayer optical functional coating according to claim 1, characterized in that, The raw materials for preparing the anti-fingerprint layer include polydimethylsiloxane and organic solvent, wherein the volume ratio of polydimethylsiloxane to organic solvent is 1:(5-20).

9. A method for preparing a multilayer optical functional coating as described in any one of claims 1-8, characterized in that, Includes the following steps: 1) Coat the surface of a transparent substrate with an anti-reflective sol to form an anti-reflective layer; 2) A low-refractive-index sol containing nano-hollow silica microspheres is coated onto the surface of the anti-reflection layer to form an anti-glare layer; 3) An anti-fingerprint solution is dipped into the surface of the anti-glare layer to form an anti-fingerprint layer, thus obtaining the multilayer optical functional coating.

10. The application of the multilayer optical functional coating according to any one of claims 1-8 in display panels, touch interfaces, optical elements or transparent devices.

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