Highly transparent composite heat insulation film and preparation method thereof
By optimizing the multilayer film structure and ion beam-assisted deposition process using genetic algorithms, multiple subwavelength thickness film units were designed. This resolved the contradiction between visible light transmittance and near-infrared reflectance in existing high-transparency heat insulation films, improving design efficiency and optimization accuracy, reducing processing difficulty and cost, and enhancing heat insulation performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GREATER BAY AREA UNIV (IN PREPARATION)
- Filing Date
- 2025-08-04
- Publication Date
- 2026-06-30
AI Technical Summary
Existing high-transparency heat insulation films have a contradiction between visible light transmittance and near-infrared reflectance, resulting in low design efficiency. Furthermore, stress accumulation and interface defects are prone to occur during the preparation of thick films, leading to high processing difficulty and cost.
A genetic algorithm was used to optimize the structure of the multilayer film system. Combined with the thermal evaporation vacuum coating process of ion beam assisted deposition, multiple subwavelength thickness film units were designed. Through multi-cycle stacking, the combination of film parameters was optimized to reduce the processing difficulty and cost.
It achieves high near-infrared reflectivity under high transparency, improves design efficiency and optimization accuracy, reduces processing difficulty and cost, and enhances thermal insulation performance.
Smart Images
Figure CN121107712B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heat insulation film technology, specifically to a high-transmittance composite heat insulation film and its preparation method. Background Technology
[0002] Air conditioning, ventilation, heating, and cooling systems account for nearly 40% of building energy consumption. With the continuous growth of individual thermal comfort demands, the proportion of air conditioning energy consumption will continue to rise, exacerbating carbon emissions and environmental problems such as global warming. As one of the main sources of energy consumption in my country, the development of building energy conservation plays a crucial role in my country's energy conservation, carbon reduction, upgrading, and green economic transformation, and has become a core area for promoting low-carbon energy transformation. Windows are an important component of buildings, and glass curtain walls are very popular, especially in skyscrapers. However, glass windows are the least energy-efficient part of a building because they indiscriminately transmit all solar radiation. Near-infrared radiation accounts for 48% of total solar radiation energy and is the main cause of increased indoor temperature.
[0003] The primary design objective of high-transparency heat insulation films is to block near-infrared light while ensuring high transmittance in the visible light band, thereby reducing the heat load on indoor environments. Currently, high-transparency heat insulation films mainly employ two structural systems: one is a dielectric / metal / dielectric structure, such as SiO2 / Ag / SiO2 and ZnO / Ag / ZnO; the other is a dielectric multilayer structure, such as SiO2 / TiO2 and Si / SiO2. For the dielectric / metal / dielectric structure, achieving extremely high transmittance in the visible light band requires precise control of the metal layer (such as Ag), as only ultra-thin metal layers can meet this optical requirement. This poses a significant challenge to the precision of the processing technology and substantially increases manufacturing costs. For the dielectric multilayer structure, due to the inherent design contradiction between high visible light transmittance and high near-infrared reflectivity, a film thickness of 5 μm or more is typically required to balance both performance characteristics. However, such a thickness is highly susceptible to delamination or cracking at the interface of different materials during processing due to the mismatch between thermal and mechanical stresses, severely impacting product yield.
[0004] Currently reported high-transparency heat-insulating films generally suffer from insufficient visible light transmittance, with values far lower than ordinary glass, and even exhibiting a noticeable gray tint. This optical characteristic violates the basic requirements for window transparency, not only affecting visual comfort but also potentially increasing indoor lighting energy consumption due to insufficient light transmission, contradicting the original intention of building energy conservation. Furthermore, most current designs still rely on traditional empirical methods and manual parameter tuning, resulting in low design efficiency and difficulty in achieving optimal performance.
[0005] Therefore, it is necessary to provide a high-transmittance composite heat insulation film and its preparation method to improve design efficiency and optimization accuracy, enhance near-infrared reflection effect, avoid stress accumulation and interface defect problems in the thick film preparation process, and reduce processing difficulty and processing cost. Summary of the Invention
[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a high-transmittance composite heat insulation film and its preparation method, which improves design efficiency and optimization accuracy, enhances near-infrared reflection effect, avoids stress accumulation and interface defect problems in the thick film preparation process, and reduces processing difficulty and processing cost.
[0007] The inventive concept of this invention is as follows: using a genetic algorithm for membrane structure optimization design, it is possible to directly optimize multi-period structures with 10-period stacking, and quickly determine the optimal combination of membrane parameters through intelligent iterative calculation, thereby improving design efficiency and optimization accuracy; on this basis, the periodic stacking of multiple subwavelength thickness membrane units replaces the traditional single-stage thick film deposition, which not only enhances the near-infrared reflection effect, but also effectively avoids stress accumulation and interface defect problems in the thick film preparation process, greatly reducing the processing difficulty and processing cost.
[0008] The first aspect of the present invention provides a high-transparency composite heat insulation film.
[0009] Specifically, the high-transmittance composite heat insulation film comprises 8 to 10 multilayer film structures;
[0010] The multilayer film structure comprises, from bottom to top, a substrate, a first SiO2 layer, a second TiO2 layer, a third SiO2 layer, a fourth TiO2 layer, a fifth SiO2 layer, a sixth TiO2 layer, and a seventh SiO2 layer.
[0011] Preferably, the high-permeability composite heat insulation film comprises a multilayer film structure of 9 to 10 layers.
[0012] More preferably, the high-transparency composite heat insulation film comprises a multilayer film structure of 10 sheets.
[0013] Preferably, the thickness of the first SiO2 layer is 178~179 nm, the thickness of the second TiO2 layer is 13.5~14.5 nm, the thickness of the third SiO2 layer is 29~30 nm, the thickness of the fourth TiO2 layer is 113~114 nm, the thickness of the fifth SiO2 layer is 29~30 nm, the thickness of the sixth TiO2 layer is 14~15 nm, and the thickness of the seventh SiO2 layer is 178~179 nm.
[0014] More preferably, the thickness of the first SiO2 layer is 178~178.5 nm, the thickness of the second TiO2 layer is 13.5~14 nm, the thickness of the third SiO2 layer is 29~29.5 nm, the thickness of the fourth TiO2 layer is 113~113.5 nm, the thickness of the fifth SiO2 layer is 29~29.5 nm, the thickness of the sixth TiO2 layer is 14~14.5 nm, and the thickness of the seventh SiO2 layer is 178~178.5 nm.
[0015] More preferably, the thickness of the first SiO2 layer is 178.40 nm, the thickness of the second TiO2 layer is 14.00 nm, the thickness of the third SiO2 layer is 29.33 nm, the thickness of the fourth TiO2 layer is 113.01 nm, the thickness of the fifth SiO2 layer is 29.24 nm, the thickness of the sixth TiO2 layer is 14.04 nm, and the thickness of the seventh SiO2 layer is 178.12 nm.
[0016] Preferably, the substrate is made of quartz glass.
[0017] A second aspect of the present invention provides a method for preparing a high-permeability composite heat insulation film.
[0018] Specifically, it includes the following steps:
[0019] (1) Use genetic optimization algorithm to design multilayer membrane structure and obtain structural model of multilayer membrane structure;
[0020] (2) The multilayer film structure was prepared by thermal evaporation vacuum coating process with ion beam assisted deposition to obtain the multilayer film structure;
[0021] (3) Stack 8 to 10 multilayer membrane structures to obtain a high-permeability composite heat insulation film.
[0022] Preferably, in step (1), the genetic optimization algorithm for designing multilayer membrane structures includes the following steps:
[0023] Construct a fitness function, whose input parameters include the average transmittance in the visible light band, the average reflectance in the near-infrared band, and the total thickness of the film system;
[0024] Establish termination conditions: the design process stops when any of the following conditions are met: the maximum number of iterations is reached, or the change in optimal fitness is less than the threshold.
[0025] Initialize the population and generate the first generation of individuals;
[0026] The membrane structure of each individual in the population is repeated to simulate multi-period superposition. The transfer matrix is then imported to calculate the spectrum of each individual, and the average transmittance in the visible light band and the average reflectance in the near-infrared band are obtained.
[0027] The average transmittance in the visible light band and the average reflectance in the near-infrared band are input into the fitness function to calculate the fitness function value of each individual. Then, it is determined whether the stopping condition is met. If it is met, the optimization process is stopped and the structural model of the optimal membrane system is output. If it is not met, the tournament selection method is used to retain individuals with high fitness, and then crossover and mutation are performed to generate the next generation of individuals. Fitness is calculated again until the stopping condition is met.
[0028] Preferably, the size of the initial population is 500 to 1500.
[0029] More preferably, the size of the initial population is 800~1200.
[0030] More preferably, the size of the initial population is 1000.
[0031] Preferably, the probability of the crossover is 0.7 to 0.9.
[0032] More preferably, the probability of the crossover is 0.75 to 0.85.
[0033] More preferably, the probability of the intersection is 0.75.
[0034] Preferably, the probability of the mutation is 0.1 to 0.3.
[0035] More preferably, the probability of the mutation is 0.1 to 0.2.
[0036] More preferably, the probability of the mutation is 0.1.
[0037] Preferably, the membrane structure of each individual in the population is repeated 8 to 10 times.
[0038] More preferably, the membrane structure of each individual in the population is repeated 9 to 10 times.
[0039] More preferably, the membrane structure of each individual in the population is repeated 10 times.
[0040] Preferably, in step (2), the thermal evaporation vacuum coating process of ion beam assisted deposition includes the following steps: cleaning the substrate, and depositing SiO2 layer and TiO2 layer in sequence and thickness.
[0041] Preferably, the vacuum level of the deposition chamber is less than or equal to 2.0 × 10⁻⁶.-3 Pa.
[0042] Preferably, the deposition rate of the SiO2 layer is less than or equal to 0.8 nm / s.
[0043] Preferably, the deposition rate of the TiO2 layer is less than or equal to 1.2 nm / s.
[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0045] The high-transparency composite heat insulation film of the present invention maintains an average transmittance of approximately 89.6% in the visible light band while achieving a high reflectance (50.31%) in the near-infrared band. Compared with commercial heat insulation films, the visible light transmittance of the present invention is the highest, and compared with similar high-transparency films, the near-infrared reflectance of the present invention is also the highest.
[0046] This invention uses a genetic optimization algorithm for multilayer membrane design, which can directly optimize multi-period structures with 10-period stacks, greatly improving design efficiency and optimization accuracy.
[0047] The high-transmittance composite heat insulation film of the present invention is composed of multiple subwavelength thickness film units. The film units are prepared by ion beam assisted deposition (IAD) thermal evaporation vacuum coating process, which avoids the direct processing of thick multilayer films and greatly reduces the processing difficulty and processing cost. Attached Figure Description
[0048] Figure 1 A flowchart illustrating the design of a multilayer membrane structure using the genetic optimization algorithm in Example 1;
[0049] Figure 2 This is a schematic diagram of the multilayer membrane structure in Example 1;
[0050] Figure 3 The reflectance spectrum of the multilayer film structure in Example 1 is shown.
[0051] Figure 4 This is a schematic diagram of the structure of the high-transmittance composite heat insulation film in Example 1;
[0052] Figure 5 The reflectance spectrum of the high-transmittance composite heat insulation film in Example 1 is shown below.
[0053] Figure 6 The images show actual photos and infrared photos of the high-transparency composite heat insulation film of Example 1, other heat insulation films, and ordinary glass.
[0054] Figure 7 This is a schematic diagram of the multilayer membrane structure for Comparative Example 1;
[0055] Figure 8 The simulated spectrum of the multilayer film structure in Comparative Example 1 is shown.
[0056] Figure 9 This is a schematic diagram of the multilayer membrane structure for Comparative Example 2;
[0057] Figure 10 The simulated spectrum of the multilayer film structure in Comparative Example 2 is shown below.
[0058] Figure 11 This is a schematic diagram of the multilayer membrane structure for Comparative Example 3;
[0059] Figure 12 The simulated spectrum of the multilayer film structure in Comparative Example 3 is shown. Detailed Implementation
[0060] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.
[0061] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.
[0062] Example 1
[0063] The high-transparency composite heat insulation film comprises a multilayer film structure consisting of 10 layers. From bottom to top, the multilayer film structure includes a quartz glass substrate, a first SiO2 layer (178.40 nm thick), a second TiO2 layer (14.00 nm thick), a third SiO2 layer (29.33 nm thick), a fourth TiO2 layer (113.01 nm thick), a fifth SiO2 layer (29.24 nm thick), a sixth TiO2 layer (14.04 nm thick), and a seventh SiO2 layer (178.12 nm thick). A schematic diagram is shown below. Figure 2 As shown.
[0064] The preparation method includes the following steps:
[0065] (1) Using the genetic optimization algorithm to design the multilayer membrane structure, firstly, the fitness function is constructed. The input parameters of the fitness function include the average transmittance in the visible light band, the average reflectance in the near-infrared band, and the total thickness of the membrane system.
[0066] Establish termination conditions: the design process stops when any of the following conditions are met: the maximum number of iterations is reached, or the change in optimal fitness is less than the threshold.
[0067] Initialize the population with a size of 1000 and generate the first generation of individuals.
[0068] The membrane structure of each individual in the population is repeated to simulate multi-period superposition. The transfer matrix is then imported to calculate the spectrum of each individual, and the average transmittance in the visible light band and the average reflectance in the near-infrared band are obtained.
[0069] The average transmittance in the visible light band and the average reflectance in the near-infrared band are input into the fitness function to calculate the fitness function value for each individual. Then, it is determined whether the stopping condition is met. If it is, the optimization process stops, and the structural model of the optimal membrane system is output. If not, a tournament selection method is used to retain individuals with high fitness, followed by crossover (crossover probability of 0.75) and mutation (mutation probability of 0.1) to generate the next generation of individuals. Fitness calculation continues until the stopping condition is met, resulting in the structural model of the multilayer membrane system (flowchart shown). Figure 1 (as shown)
[0070] (2) The structural model of the multilayer film system was prepared using a thermal evaporation vacuum coating process with ion beam assisted deposition. First, the quartz glass substrate was cleaned using deionized water to remove impurities, then immersed in anhydrous ethanol and cleaned in an ultrasonic cleaner. Finally, nitrogen gas was used to dry the substrate, ensuring the quartz glass surface was free of dust, grease, or other contaminants. Subsequently, in the thermal evaporation vacuum coating equipment, each layer of material was deposited sequentially according to the following order and thickness:
[0071] First layer: SiO2, 178.40nm;
[0072] Second layer: TiO2, 14.00nm;
[0073] Third layer: SiO2, 29.33nm;
[0074] Fourth layer: TiO2, 113.01nm;
[0075] Fifth layer: SiO2, 29.24nm;
[0076] Sixth layer: TiO2, 14.04nm;
[0077] Seventh layer: SiO2, 178.12nm;
[0078] During the preparation and deposition processes, the chamber vacuum level is maintained at less than or equal to 2.0 × 10⁻⁶. -3 The deposition rate of SiO2 is less than or equal to 0.8 nm / s, and the deposition rate of TiO2 is less than or equal to 1.2 nm / s, to ensure the uniformity and quality of the film layer and to fabricate a multilayer film structure.
[0079] (3) Using Norland high-transparency optical adhesive (NOA61) as the adhesive medium, 10 multilayer film structures were precisely stacked to obtain a high-transparency composite heat insulation film (see schematic diagram). Figure 4 ).
[0080] Comparative Example 1
[0081] The high-transparency composite heat insulation film comprises a multilayer film structure consisting of 10 layers. From bottom to top, the multilayer film structure includes a quartz glass substrate, a first TiO2 layer (178.40 nm thick), a second SiO2 layer (14.00 nm thick), a third TiO2 layer (29.33 nm thick), a fourth SiO2 layer (113.01 nm thick), a fifth TiO2 layer (29.24 nm thick), a sixth SiO2 layer (14.04 nm thick), and a seventh TiO2 layer (178.12 nm thick). A schematic diagram of the structure is shown below. Figure 7 As shown.
[0082] The preparation method includes the following steps:
[0083] (1) Using the genetic optimization algorithm to design the multilayer membrane structure, firstly, the fitness function is constructed. The input parameters of the fitness function include the average transmittance in the visible light band, the average reflectance in the near-infrared band, and the total thickness of the membrane system.
[0084] Establish termination conditions: the design process stops when any of the following conditions are met: the maximum number of iterations is reached, or the change in optimal fitness is less than the threshold.
[0085] Initialize the population with a size of 1000 and generate the first generation of individuals.
[0086] The membrane structure of each individual in the population is repeated to simulate multi-period superposition. The transfer matrix is then imported to calculate the spectrum of each individual, and the average transmittance in the visible light band and the average reflectance in the near-infrared band are obtained.
[0087] The average transmittance in the visible light band and the average reflectance in the near-infrared band are input into the fitness function to calculate the fitness function value of each individual. Then, it is determined whether the stopping condition is met. If it is met, the optimization process stops and the structural model of the optimal membrane system is output. If it is not met, the tournament selection method is used to retain individuals with high fitness, and then crossover (crossover probability of 0.75) and mutation (mutation probability of 0.1) are performed to generate the next generation of individuals. The fitness is calculated again until the stopping condition is met, and the structural model of the multilayer membrane system is obtained.
[0088] (2) The structural model of the multilayer film system was prepared using a thermal evaporation vacuum coating process with ion beam assisted deposition. First, the quartz glass substrate was cleaned using deionized water to remove impurities, then immersed in anhydrous ethanol and cleaned in an ultrasonic cleaner. Finally, nitrogen gas was used to dry the substrate, ensuring the quartz glass surface was free of dust, grease, or other contaminants. Subsequently, in the thermal evaporation vacuum coating equipment, each layer of material was deposited sequentially according to the following order and thickness:
[0089] First layer: TiO2, 178.40nm;
[0090] Second layer: SiO2, 14.00nm;
[0091] Third layer: TiO2, 29.33nm;
[0092] Fourth layer: SiO2, 113.01nm;
[0093] Fifth layer: TiO2, 29.24nm;
[0094] Sixth layer: SiO2, 14.04nm;
[0095] Seventh layer: TiO2, 178.12nm;
[0096] During the preparation and deposition processes, the chamber vacuum level is maintained at less than or equal to 2.0 × 10⁻⁶. -3 The deposition rate of SiO2 is less than or equal to 0.8 nm / s, and the deposition rate of TiO2 is less than or equal to 1.2 nm / s, to ensure the uniformity and quality of the film layer and to fabricate a multilayer film structure.
[0097] (3) Using Norland high-transparency optical adhesive (NOA61) as the adhesive medium, 10 multilayer film structures are precisely stacked to obtain a high-transparency composite heat insulation film.
[0098] Comparative Example 2
[0099] A composite heat insulation film.
[0100] The difference from Example 1 is that the multilayer film structure lacks a fourth TiO2 layer (see schematic diagram). Figure 9 (As shown), the remaining structures and preparation methods are the same as in Example 1.
[0101] Comparative Example 3
[0102] A composite heat insulation film.
[0103] The difference from Example 1 is that the number of iterations in the genetic algorithm is too small, that is, the membrane structure of each individual in the population is repeated only once (see the structural diagram). Figure 11(As shown), the remaining structures and preparation methods are the same as in Example 1.
[0104] Performance testing:
[0105] The test results of the reflectance spectral performance of the multilayer film structure in Example 1 are as follows: Figure 3 As shown by the solid line, actual data shows that this multilayer film system has an average reflectance of 7.91% in the visible light band (400~800 nm) and an average reflectance of 12.62% in the near-infrared band (800~2500 nm). Compared with theoretical simulation results ( Figure 3 (dashed line) The measured reflectance spectrum is higher, which may be due to two factors: First, the refractive index parameters of the actual deposited film are different from those of the material used in the simulation, resulting in enhanced interface reflection; second, the crystal oscillator control system of the thermal evaporation vacuum coating equipment also has random errors, resulting in inconsistencies between the actual deposition thickness and the preset thickness, which will also lead to differences between the measured spectrum and the simulated spectrum.
[0106] Example 1: Test results of the reflectance spectrum performance of high-transmittance composite heat insulation film ( Figure 5 (Solid line) indicates that the high-transmittance composite heat insulation film of Example 1 exhibits excellent selective spectral characteristics: it maintains an average reflectance of 10.40% in the visible light band (400~800 nm) and achieves an average reflectance of 50.31% in the near-infrared band (800~2500 nm). This unique performance stems from the following design advantages: (1) through the multilayer superposition effect, the near-infrared reflectance is increased by about 4 times compared with the single-layer film, which significantly enhances the heat radiation blocking ability; (2) thanks to the high initial transmittance of 92.09% of each single-layer film, the composite film after superposition still maintains 89.6% transmittance in the visible light region, perfectly balancing the lighting requirements and heat insulation performance. The test data fully verify the feasibility of the technical route of performance enhancement achieved by controllable superposition in this invention. Compared with the theoretical simulation results ( Figure 5 (dashed line) The difference between the measured reflection spectrum and the simulation result may be due to the interfacial refractive index matching effect of the adhesive medium. The optical adhesive forms a gradient refractive index transition region between the SiO2 and TiO2 layers, which effectively reduces the Fresnel reflection loss at the multilayer interface and causes a slight decrease in reflectivity.
[0107] Temperature tests were conducted on ordinary glass, two commercial heat insulation films, and the high-transparency composite heat insulation film prepared in Example 1 of this invention under clear outdoor conditions. Photos of the actual products and infrared camera images are shown below. Figure 6As shown in the image, to minimize the impact of heat convection and conduction, a transparent PE film was used to cover the device. Infrared images show that under sunlight, the ordinary glass group had the highest temperature, reaching 57.1°C. The temperatures of the two commercial heat-insulating films were slightly lower than those of the ordinary glass group, at 50.5°C and 42.7°C, respectively, representing decreases of 6.6°C and 14.4°C. In contrast, the high-transparency composite heat-insulating film prepared in Example 1 of this invention had the lowest temperature, at only 34.1°C, a decrease of 23°C compared to ordinary glass, and decreases of 16.4°C and 8.6°C compared to the two commercial heat-insulating films, respectively. It exhibited excellent cooling performance while maintaining high transparency.
[0108] like Figure 8 As shown, compared with the high-transmittance composite heat insulation film designed and prepared in Example 1 of this invention, although the near-infrared reflectance performance of Comparative Example 1 is improved (average reflectance of 58.67% after ten cycles are superimposed), the transmission performance in the visible light band is significantly reduced (average reflectance of 61.05%), which is not conducive to achieving the visual visibility of the heat insulation film. Figure 10 As shown, in Comparative Example 2, both the visible light transmission performance (average reflectivity 18.30%) and near-infrared reflectivity (average reflectivity 15.81%) decreased, with the near-infrared reflectivity showing a greater decrease. Figure 12 As shown, the genetic algorithm in Comparative Example 3 had too few iterations, which resulted in the algorithm not converging correctly. Its near-infrared reflectivity (average reflectivity 58.88%) was improved, but its transmission performance in the visible light band was reduced (average reflectivity 38.17%).
[0109] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, any technical solutions obtained by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concept of the present invention and on the existing technology should be within the scope of protection defined by the claims.
Claims
1. A high-transmittance composite heat insulation film, characterized in that, It includes a multilayer membrane structure of 8 to 10 sheets; The multilayer film structure consists of a substrate, a first SiO2 layer, a second TiO2 layer, a third SiO2 layer, a fourth TiO2 layer, a fifth SiO2 layer, a sixth TiO2 layer, and a seventh SiO2 layer, from bottom to top. The thickness of the first SiO2 layer is 178.40 nm, the thickness of the second TiO2 layer is 14.00 nm, the thickness of the third SiO2 layer is 29.33 nm, the thickness of the fourth TiO2 layer is 113.01 nm, the thickness of the fifth SiO2 layer is 29.24 nm, the thickness of the sixth TiO2 layer is 14.04 nm, and the thickness of the seventh SiO2 layer is 178.12 nm.
2. The high-transmittance composite heat insulation film according to claim 1, characterized in that, The substrate is made of quartz glass.
3. The method for preparing the high-transmittance composite heat insulation film according to any one of claims 1 to 2, characterized in that, Includes the following steps: (1) Use genetic optimization algorithm to design multilayer membrane structure and obtain structural model of multilayer membrane structure; (2) The multilayer film structure was prepared by thermal evaporation vacuum coating process with ion beam assisted deposition to obtain the multilayer film structure; (3) Stack 8 to 10 multilayer membrane structures to obtain a high-permeability composite heat insulation film.
4. The preparation method according to claim 3, characterized in that, In step (1), the genetic optimization algorithm for designing multilayer membrane structures includes the following steps: Construct a fitness function, whose input parameters include the average transmittance in the visible light band, the average reflectance in the near-infrared band, and the total thickness of the film system; Establish termination conditions: the design process stops when any of the following conditions are met: the maximum number of iterations is reached, or the change in optimal fitness is less than the threshold. Initialize the population and generate the first generation of individuals; The membrane structure of each individual in the population is repeated to simulate multi-period superposition. The transfer matrix is then imported to calculate the spectrum of each individual, and the average transmittance in the visible light band and the average reflectance in the near-infrared band are obtained. The average transmittance in the visible light band and the average reflectance in the near-infrared band are input into the fitness function to calculate the fitness function value of each individual. Then, it is determined whether the stopping condition is met. If it is met, the optimization process is stopped and the structural model of the optimal membrane system is output. If it is not met, the tournament selection method is used to retain individuals with high fitness, and then crossover and mutation are performed to generate the next generation of individuals. Fitness is calculated again until the stopping condition is met.
5. The preparation method according to claim 4, characterized in that, The membrane structure of each individual in the population is repeated 8 to 10 times.
6. The preparation method according to claim 4, characterized in that, In step (2), the thermal evaporation vacuum coating process of ion beam assisted deposition includes the following steps: cleaning the substrate, and depositing SiO2 layer and TiO2 layer in sequence and thickness.
7. The preparation method according to claim 6, characterized in that, The chamber vacuum of the deposition is less than or equal to 2.0 x 10 -3 Pa.
8. The preparation method according to claim 6, characterized in that, The deposition rate of the SiO2 layer is less than or equal to 0.8 nm / s.
9. The preparation method according to claim 6, characterized in that, The deposition rate of the TiO2 layer is less than or equal to 1.2 nm / s.