Manufacturing method of transparent sound-absorbing screen and transparent sound-absorbing screen

Abstract

This invention provides a method for manufacturing a transparent sound-absorbing screen and the transparent sound-absorbing screen itself, belonging to the field of transparent sound-absorbing screen processing technology. The method includes: preparation of a transparent sound-absorbing panel: perforating a transparent plate to form a transparent perforated substrate, attaching a transparent film to the transparent perforated substrate, and processing micro-slits on the transparent film corresponding to the holes in the transparent perforated substrate to obtain the transparent sound-absorbing panel; preparation of a transparent sound-insulating back panel: cutting a transparent sheet to form a transparent sound-insulating back panel; preparation of a frame: forming a frame through machining; and final assembly: installing the sound-absorbing panel and the sound-insulating back panel onto the frame. By processing the sound-absorbing panel, sound-insulating back panel, and frame separately and then assembling them uniformly, and by using theoretical calculations to ensure the accuracy and reliability of the design results, the invention significantly improves the success rate of developing new sound-absorbing structures that meet complex comprehensive performance requirements. Furthermore, the structure is simple and easy to process.

Description

Technical Field

[0001] This invention belongs to the field of transparent sound-absorbing screen processing technology, specifically, it relates to a method for manufacturing a transparent sound-absorbing screen and the transparent sound-absorbing screen itself. Background Technology

[0002] Currently, in the field of noise control, such as urban sound barriers, the commonly used structure is a porous sound-absorbing material, such as glass wool or rock wool, filled within a perforated metal substrate. However, this type of structure has several drawbacks. First, its opaque nature makes it difficult to integrate with modern urban landscapes. Second, its sound absorption performance in the mid-to-low frequency range is generally insufficient. Furthermore, the fiber materials used have poor weather resistance, easily absorbing water and settling, leading to bacterial growth. This not only causes a decline in sound absorption performance but also releases fiber dust that poses a potential threat to human health. Therefore, improvements are needed in terms of environmental friendliness, durability, and health safety.

[0003] A Chinese patent application with publication number CN107345387A discloses a novel sound-absorbing barrier, comprising a crash barrier, an H-steel column, and a sound barrier. The sound barrier is disposed within the H-steel column and fixed to the crash barrier by the H-steel column. The sound barrier includes an upper composite through-hole sound-absorbing screen at the top, a transparent glass sound barrier in the middle, and a lower composite through-hole sound-absorbing screen at the bottom. The upper part of the upper composite through-hole sound-absorbing screen is bent backward, and the top of the upper composite through-hole sound-absorbing screen is provided with an arc-shaped top cover plate.

[0004] The existing technology, which sets the sound barrier as an upper composite through-hole sound-absorbing screen at the top, a transparent glass sound barrier in the middle, and a lower composite through-hole sound-absorbing screen at the bottom, has a complex structure, is inconvenient to process, and has room for improvement. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for manufacturing a transparent sound-absorbing screen and the transparent sound-absorbing screen itself.

[0006] A method for manufacturing a transparent sound-absorbing screen according to the present invention includes: Transparent sound-absorbing panel preparation: A transparent perforated substrate is formed by perforating a transparent plate, a transparent film is attached to the transparent perforated substrate, and micro-slits are formed on the transparent film at the holes of the transparent perforated substrate to obtain the transparent sound-absorbing panel. Soundproof back panel preparation: Transparent sheet material is cut to form a transparent soundproof back panel; Border preparation: The border is formed by machining; Finished product assembly: The sound-absorbing panel and the sound-insulating back panel are installed on the frame. The sound-absorbing panel and the sound-insulating back panel are set at a distance from front to back and form an air acoustic cavity layer. The frame is installed around the sound-absorbing panel and the sound-insulating back panel with fasteners to form a transparent sound-absorbing screen finished product.

[0007] In a preferred embodiment, the processing geometric parameters of the transparent perforated substrate, the transparent micro-slit film, the air acoustic cavity layer, and the transparent sound insulation back panel are calculated, including the following steps: S10, Target Design and Index Determination Stage: Determine the target design values ​​for the sound absorption performance, sound insulation performance, light transmission performance, mechanical performance, and structural size requirements of a transparent sound-absorbing screen, and preset the error threshold for comparing experimental and simulation results. S20. In the theoretical analysis and parameter estimation stage, using acoustic theory and empirical models, and in conjunction with the target design values, the range of variation of the geometric parameters of each component constituting the transparent sound-absorbing screen is initially calculated and determined. S30. In the numerical simulation and parameter optimization stage, within the range of variation of the geometric parameters, multiphysics simulation software is used to perform numerical simulation and iterative optimization on the transparent sound-absorbing screen until the simulated sound absorption performance requirements, sound insulation performance requirements, light transmission performance requirements, mechanical performance requirements and structural size requirements all meet the target design values, thereby determining an optimal combination of geometric parameters. S40. Experimental Verification and Feedback Correction Stage: Based on the preferred geometric parameters, a sample is fabricated and its acoustic, light transmission, and mechanical properties are tested. The experimental test results are compared with the numerical simulation results. If the difference between the experimental test results and the simulation results is greater than a preset threshold, or if the sound absorption performance, light transmission performance, and mechanical properties in the experimental test results do not all meet the target design values, then the numerical simulation and parameter optimization stage is returned to correct the physical model, model parameters, or boundary conditions used in the numerical simulation, or the geometric parameters are adjusted and iterated repeatedly until the measured sound absorption performance, light transmission performance, and mechanical properties of the sample all meet the target design values.

[0008] In a preferred embodiment, for S10, the target design values ​​for the transparent sound-absorbing screens on both sides of the traffic line include: Sound absorption performance requirements: The noise reduction coefficient (NRC) of the screen shall not be less than 0.60; Sound insulation performance requirements: weighted sound insulation of the screen R w Not less than 30dB; Light transmittance requirements: The visible light transmittance of the screen shall not be less than 70%; Mechanical performance requirements: The bending stiffness of the sound-absorbing panel shall not be less than 4 N·m; Structural dimensional requirements: The total thickness of the screen body shall not exceed 100mm; Error threshold setting: The average relative error should be less than 5%.

[0009] In a preferred embodiment, step S20 includes the following steps: S21. Based on the sound absorption performance requirements and structural dimension requirements, estimate the maximum sound absorption coefficient under the normal incident direction of the sound wave in reverse. α max Resonant absorption frequency f 0 and effective sound absorption frequency range f UL The optimal range, initially determining the effective range of the product's acoustic impedance, and the effective sound absorption frequency band. f UL This refers to the ratio of the upper limit to the lower limit of the effective sound absorption frequency. S22. Based on the product's light transmittance requirements, preliminarily determine the materials for the transparent perforated substrate, transparent film, and sound insulation back panel; S23. Based on the mechanical performance requirements of the product, the thickness of the transparent perforated substrate is initially estimated, and the effective range of the hole diameter and hole spacing of the transparent perforated substrate is initially determined based on the ease of processing, light transmittance and structural stability. S24. Based on the effective range of the thickness, aperture and spacing of the transparent perforated substrate determined in the previous step, calculate the acoustic impedance contributed by the transparent perforated substrate. S25. Based on the sound insulation performance requirements of the product and the material of the sound insulation back panel determined in S22, determine the surface density and thickness of the sound insulation back panel. S26. Based on the total thickness, the thickness of the transparent perforated substrate and the sound insulation backing, determine the thickness of the air acoustic cavity layer, and then calculate the acoustic impedance contributed by the air acoustic cavity layer. S27. Based on the effective range of acoustic impedance determined in S21, the acoustic impedance contributed by the transparent perforated substrate determined in S24, and the acoustic impedance contributed by the air acoustic cavity layer determined in S26, calculate and determine the effective range of acoustic impedance of the micro-slit film. S28. Based on the effective range of acoustic impedance of the micro-slit film determined in the previous step, preliminarily estimate the range of variation of geometric parameters such as the thickness of the transparent film, the width of the micro-slit, and the perforation rate.

[0010] In a preferred embodiment, for S30, the following steps are further included: S31. Establish a simulation model. Use commercial finite element software to establish a three-dimensional numerical simulation model of a single periodic unit of the transparent sound-absorbing screen. The transparent sound-absorbing screen is formed by the combination of a transparent sound-absorbing panel and a sound-insulating back panel. S32. Within the theoretically estimated parameter range, perform parametric scanning and iterative optimization, fix all other geometric parameters, and use only one geometric parameter as a variable to scan with a preset step size, and simulate and solve the sound pressure, velocity, temperature, viscothermal energy loss distribution and transmission impedance.

[0011] In a preferred embodiment, step S40 includes the following steps: S41. Based on the geometric parameter combination in step S30, process and manufacture small-sized impedance tube samples; S42. Perform impedance tube testing to test the sound absorption performance under normal incident sound wave inside the impedance tube. S43. Comparing the simulation and experimental results, if the average relative error is less than 5%, it indicates that the numerical simulation model established at this stage can accurately predict the acoustic behavior of the structure, and the model has been verified. If the average relative error is not less than 5%, it indicates that the simulation model has failed to accurately reflect the physical reality. The feedback correction loop is initiated, and the simulation returns to the numerical simulation and parameter optimization stage S30. S44. Conduct reverberation chamber testing. Based on the geometric parameters of the verified model, fabricate a large-size prototype that meets the application dimensions and test it in the reverberation chamber to obtain the final performance indicators. S45. Compare the noise reduction coefficient obtained by actual measurement in the reverberation chamber with the target design value of sound absorption performance set in the target design and index determination stage S10. If the target design value is met, the standard is met. S46. Conduct tests on sound insulation performance, light transmittance performance, mechanical performance, etc., to obtain performance indicators such as weighted sound insulation, visible light transmittance, and bending stiffness. Compare these with the target design values ​​set in the target design and indicator determination stage S10. If the target design values ​​are met, the standard is met. If the target design value is not met, return to the numerical simulation and parameter optimization stage S30 to check and correct the geometric parameters in the simulation model, and then repeat the subsequent simulation, prototype manufacturing, testing and verification process until the actual performance of the final product meets the target design value.

[0012] In a preferred embodiment, the process of fabricating micro-slits on the transparent film corresponding to the holes in the transparent perforated substrate includes laser cutting or mechanical scribing.

[0013] In a preferred embodiment, the slit width processed on the transparent film should be in the range of 0.05 mm to 0.15 mm, and the perforation rate should be in the range of 0.5% to 2%.

[0014] In a preferred embodiment, the transparent film is made of materials including polyester film, fluoropolymer film, polycarbonate, polyolefin, and polyurethane film. The materials used for transparent perforated substrates and sound-insulating back panels include polyester, polycarbonate, acrylic polymers, polyurethane, and fluoropolymers.

[0015] According to the present invention, a transparent sound-absorbing screen includes a sound-absorbing panel and a sound-insulating back panel arranged at intervals, an air acoustic cavity layer is formed between the sound-absorbing panel and the sound-insulating back panel, and a frame is installed around the transparent sound-absorbing panel and the sound-insulating back panel.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention processes the sound-absorbing panel, sound-insulating back panel, and frame separately, and then assembles them together. Theoretical calculations are used to ensure the accuracy and reliability of the design results, which significantly improves the success rate of developing new sound-absorbing structures that meet complex comprehensive performance requirements. Moreover, the structure is simple and easy to process.

[0017] 2. By performing theoretical calculations before simulation, this invention reduces the search space for design parameters in advance, avoiding blind and computationally expensive simulation attempts with a large number of parameter combinations, thereby significantly improving R&D efficiency.

[0018] 3. The method of this invention can successfully design a structure that combines high light transmittance and excellent sound absorption performance. In particular, it solves the problem that traditional transparent screens are difficult to achieve broadband sound wave absorption, fills a market gap, and meets the needs of scenarios such as transparent sound barriers that have both functional and aesthetic requirements.

[0019] 4. The large-pore substrate composite micro-slit film structure of the present invention achieves decoupling design of mechanical properties and acoustic functions, which facilitates independent optimization of mechanical strength and sound absorption performance. At the same time, the structure replaces traditional inorganic fiber materials such as mineral wool with polymer film or metal foil film, realizing fiber-free sound absorption, fundamentally avoiding the health risks to the human body and secondary pollution to the environment caused by fiber leakage, making the product safer and more durable. Attached Figure Description

[0020] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating the manufacturing method of the transparent sound-absorbing screen, which is the main feature of this invention. Figure 2 This is a flowchart illustrating the design method of the present invention. Figure 3 This is a flowchart illustrating the parameter estimation stage of the present invention. Figure 4 The flowcharts are mainly used to illustrate the numerical simulation and parameter optimization stages, as well as the experimental verification and feedback correction stages of this invention. Detailed Implementation

[0021] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0022] Example 1 like Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, a method for manufacturing a transparent sound-absorbing screen according to the present invention includes: Transparent sound-absorbing panel preparation: A transparent perforated substrate is formed by perforating a transparent plate, a transparent film is attached to the transparent perforated substrate, and micro-slits are formed on the transparent film corresponding to the positions of the holes in the transparent perforated substrate to obtain the transparent sound-absorbing panel.

[0023] Transparent sound insulation back panel preparation: Transparent sheet material is cut to form a transparent sound insulation back panel.

[0024] Border preparation: The border is formed by machining.

[0025] Finished product assembly: The sound-absorbing panel and the sound-insulating back panel are installed on the frame. The sound-absorbing panel and the sound-insulating back panel are set at a distance from front to back and form an air acoustic cavity layer. The frame is installed around the sound-absorbing panel and the sound-insulating back panel with fasteners to form a transparent sound-absorbing screen finished product.

[0026] The processing geometric parameters of the transparent perforated substrate, transparent micro-slit film, air acoustic cavity layer, and transparent sound insulation back panel in this application are obtained through calculation, including the following steps: S10, Target Design and Index Determination Stage: Target design values ​​are determined for the sound absorption performance, sound insulation performance, light transmission performance, mechanical performance, and structural dimensional requirements of a transparent sound-absorbing screen. An error threshold is preset for comparing experimental and simulation results. In one feasible implementation, the target design values ​​for the transparent sound-absorbing screens on both sides of the traffic route include: Sound absorption performance requirements: The noise reduction coefficient (NRC) of the screen shall not be less than 0.60; Sound insulation performance requirements: weighted sound insulation of the screen R w Not less than 30dB; Light transmittance requirements: The visible light transmittance of the screen shall not be less than 70%; Mechanical performance requirements: The bending stiffness of the sound-absorbing panel shall not be less than 4 N·m; Structural dimensional requirements: The total thickness of the screen body shall not exceed 100mm; Error threshold setting: The average relative error should be less than 5%.

[0027] S20. In the theoretical analysis and parameter estimation stage, using acoustic theory and empirical models, and in conjunction with the target design values, the range of variation of the geometric parameters of each component constituting the transparent sound-absorbing screen is initially calculated and determined. The transparent sound-absorbing screen is formed by the combination of a transparent sound-absorbing panel and a sound-insulating back panel.

[0028] Specifically, it includes the following steps: S21. Based on the sound absorption performance requirements and structural dimension requirements, estimate the maximum sound absorption coefficient under the normal incident direction of the sound wave in reverse. α max Resonant absorption frequency f 0 and effective sound absorption frequency range f UL The optimal range, initially determining the effective range of the product's acoustic impedance, and the effective sound absorption frequency band. f UL This refers to the ratio of the upper limit to the lower limit of the effective sound absorption frequency. S22. Based on the product's light transmittance requirements, preliminarily determine the materials for the transparent perforated substrate, transparent film, and sound insulation back panel; S23. Based on the mechanical performance requirements of the product, the thickness of the transparent perforated substrate is initially estimated, and the effective range of the hole diameter and hole spacing of the transparent perforated substrate is initially determined based on the ease of processing, light transmittance and structural stability. S24. Based on the effective range of the thickness, aperture and spacing of the transparent perforated substrate determined in the previous step, calculate the acoustic impedance contributed by the transparent perforated substrate. S25. Based on the sound insulation performance requirements of the product and the material of the sound insulation back panel determined in S22, determine the surface density and thickness of the sound insulation back panel. S26. Based on the total thickness, the thickness of the transparent perforated substrate and the sound insulation backing, determine the thickness of the air acoustic cavity layer, and then calculate the acoustic impedance contributed by the air acoustic cavity layer. S27. Based on the effective range of acoustic impedance determined in S21, the acoustic impedance contributed by the transparent perforated substrate determined in S24, and the acoustic impedance contributed by the air acoustic cavity layer determined in S26, calculate and determine the effective range of acoustic impedance of the micro-slit film; the micro-slit film is a structure in which micro-slits are processed on a transparent film.

[0029] S28. Based on the effective range of acoustic impedance of the micro-slit film determined in the previous step, preliminarily estimate the range of variation of geometric parameters such as film thickness, micro-slit width and perforation rate.

[0030] S30. In the numerical simulation and parameter optimization stage, within the range of variation of the geometric parameters, multiphysics simulation software is used to perform numerical simulation and iterative optimization on the transparent sound-absorbing screen until the simulated sound absorption performance requirements, sound insulation performance requirements, light transmission performance requirements, mechanical performance requirements, and structural dimension requirements all meet the target design values, thereby determining an optimal combination of geometric parameters. Specifically, Includes the following steps: S31. Establish a simulation model. Select commercial finite element software to establish a three-dimensional numerical simulation model of a single periodic unit of the transparent sound-absorbing structure. The transparent sound-absorbing structure is formed by the combination of a transparent sound-absorbing panel and a transparent sound-insulating back panel. S32. Within the theoretically estimated parameter range, perform parametric scanning and iterative optimization, fix all other geometric parameters, and use only one geometric parameter as a variable to scan with a preset step size, and simulate and solve the sound pressure, velocity, temperature, viscothermal energy loss distribution and transmission impedance.

[0031] Using multiphysics simulation software, precise numerical calculations and iterative optimizations are performed within the theoretically defined parameter range to calculate the transmission impedance and sound absorption coefficient of the sound-absorbing panel, predict the corresponding noise reduction coefficient, and compare the predicted noise reduction coefficient with the target value set in the target design and index determination stage S10. If the target is not achieved, adjust one or more geometric parameters and repeat the simulation calculation. If the objective is achieved, save the geometric parameter combination and proceed to step S40.

[0032] S40. Experimental verification and feedback correction stage: Based on the selected geometric parameters, a sample is made and its acoustic, light transmission and mechanical properties are tested. The experimental test results are compared with the numerical simulation results. If the difference between the experimental test results and the simulation results is greater than the preset threshold, or if the sound absorption performance, light transmission performance and mechanical properties in the experimental test results do not all meet the target design values, then return to the numerical simulation and parameter optimization stage to correct the physical model, model parameters or boundary conditions used in the numerical simulation, or adjust the geometric parameters and repeat the iteration until the measured sound absorption performance, light transmission performance and mechanical properties of the sample all meet the target design.

[0033] Specifically, step S40 includes the following steps: S41. Based on the geometric parameter combination in step S30, process and manufacture small-sized impedance tube samples; S42. Perform impedance tube testing to test the sound absorption performance under normal incident sound wave inside the impedance tube. S43. Comparing the simulation and experimental results, if the average relative error is less than 5%, it indicates that the numerical simulation model established at this stage can accurately predict the acoustic behavior of the structure, and the model has been verified. If the average relative error is not less than 5%, it indicates that the simulation model has failed to accurately reflect the physical reality. The feedback correction loop is initiated, and the simulation returns to the numerical simulation and parameter optimization stage S30. S44. Conduct reverberation chamber testing. Based on the geometric parameters of the verified model, fabricate a large-size prototype that meets the application dimensions and test it in the reverberation chamber to obtain the final performance indicators. S45. Compare the noise reduction coefficient obtained by actual measurement in the reverberation chamber with the target design value of sound absorption performance set in the target design and index determination stage S10. If the target design value is met, the standard is met. S46. Conduct tests on sound insulation performance, light transmittance performance, mechanical performance, etc., to obtain performance indicators such as weighted sound insulation, visible light transmittance, and bending stiffness. Compare these with the target design values ​​set in the target design and indicator determination stage S10. If the target design values ​​are met, the standard is met. If the target design value is not met, return to the numerical simulation and parameter optimization stage S30 to check and correct the geometric parameters in the simulation model, and then repeat the subsequent simulation, prototype manufacturing, testing and verification process until the actual performance of the final product meets the target design value.

[0034] It should be noted that the geometric parameters include at least one of the following: the thickness, aperture, and spacing of the transparent perforated substrate, and the thickness, width, length, number of slits, and spacing of the microslit film.

[0035] In a preferred embodiment, the process of fabricating micro-slits on the transparent film corresponding to the holes in the transparent perforated substrate includes laser cutting or mechanical scribing. The width of the slits fabricated on the transparent film should be in the range of 0.05 mm to 0.15 mm, and the perforation rate should be in the range of 0.5% to 2%. The transparent film is made of materials including polyester film, fluoropolymer film, polycarbonate, polyolefin, and polyurethane film. The transparent perforated substrate is made of materials including polyester, polycarbonate, acrylic polymer, polyurethane, and fluoropolymer.

[0036] According to the present invention, a transparent sound-absorbing screen includes a sound-absorbing panel and a sound-insulating back panel arranged at intervals, an air acoustic cavity layer is formed between the sound-absorbing panel and the sound-insulating back panel, and a frame is installed around the sound-absorbing panel and the sound-insulating back panel.

[0037] Example 2 Based on Embodiment 1, an iterative optimization design method for the fabrication of transparent sound-absorbing screens is provided, taking a transparent sound-absorbing screen as an example to design its core sound-absorbing unit. This constitutes a complete closed loop including target design and performance determination, theoretical analysis and parameter estimation, numerical simulation and parameter optimization, and experimental verification and feedback correction.

[0038] Specifically, the method may include a target design and index determination stage S10, a theoretical analysis and parameter estimation stage S20, a numerical simulation and parameter optimization stage S30, and an experimental verification and feedback correction stage S40.

[0039] In the target design and performance determination phase S10, the design objective of this embodiment is to develop a transparent sound-absorbing barrier with high light transmittance, strong sound absorption, and high load-bearing capacity, placed between the noise source and the sound-receiving point to reduce the impact of traffic noise and protect the area where the sound-receiving point is located. The sound barrier can block direct sound, attenuate diffracted sound, reduce reflected sound, and isolate transmitted sound, and is mainly used in applications such as sound barriers along traffic routes that also require transparent sound absorption. Based on its specific application scenario, a set of comprehensive and quantifiable target design values ​​were determined. Specifically: Sound absorption performance requirements: Good sound absorption performance can reduce reflected sound from the screen, enhance diffraction attenuation, and improve the actual noise reduction effect of the screen. In this embodiment, the noise reduction coefficient (NRC) of the transparent sound-absorbing screen is required to be no less than 0.60. It can be understood that the noise reduction coefficient is the arithmetic mean of the sound absorption coefficients of the structure at the center frequencies of the four octave bands of 250Hz, 500Hz, 1000Hz, and 2000Hz, and is an important indicator for evaluating the sound absorption capacity of materials.

[0040] Sound insulation performance requirements: Good sound insulation performance of the screen can reduce transmitted sound and improve the actual noise reduction effect of the screen. In this embodiment, the weighted sound insulation of the transparent sound-absorbing screen is required to be... R w Not less than 30dB.

[0041] Light transmittance requirements: Currently, sound barrier panels typically use perforated panels combined with mineral wool structures. While these offer excellent sound absorption, they obstruct vision and cut into traffic lanes. To improve driver visibility and the cityscape, a transparent sound-absorbing barrier with low visual obstruction is proposed. This requires the sound barrier to have a visible light transmittance of no less than 70%, while maintaining the lowest possible haze to ensure clear visibility.

[0042] Mechanical performance requirements: Considering that the sound barrier needs to withstand the pulsating load caused by passing vehicles and the static load caused by wind and its own weight, it must have sufficient structural strength and stiffness. In this embodiment, the bending stiffness of its sound-absorbing panel is required to be no less than 4 N·m.

[0043] Structural dimensional requirements: Due to limitations in sound absorption performance, steel profile dimensions, self-weight, and materials, in this embodiment, the total thickness is required to be no less than 80mm and no more than 100mm.

[0044] Error threshold setting: To quantitatively evaluate the accuracy of subsequent simulation models, an error threshold is pre-set to compare experimental measurement results with numerical simulation prediction results. For example, the average relative error of the normal absorption coefficient curve at the center frequency of 1 / 3 octave band within the main frequency band should be less than 5%.

[0045] Subsequently, the theoretical analysis and parameter estimation stage S20 begins. This stage aims to make preliminary estimates of the geometric parameters of each component constituting the sound-absorbing structure based on acoustic theory and empirical models, thereby defining a reasonable and significantly reduced search space for subsequent computationally expensive numerical simulations to avoid blind trial and error.

[0046] The basic unit of the transparent sound-absorbing panel designed in this application embodiment mainly consists of two parts: a perforated substrate support and protective layer on the outer side, which has large holes and mainly serves to support, protect, allow for transparency, and provide an aesthetic finish; and a micro-slit thin-film sound-absorbing layer on the inner side, which has micro-slits to fully utilize its sound absorption function. It should be noted that this structure cleverly decouples the mechanical support function from the acoustic sound absorption function.

[0047] The basic unit of the transparent sound-absorbing screen designed in this application embodiment consists of three parts: the side closest to the sound source is a transparent sound-absorbing panel, which mainly plays the role of sound absorption and support; the middle layer is an air acoustic cavity layer, which mainly plays the role of adjusting the sound absorption frequency; and the side furthest from the sound source is a transparent sound-insulating back panel, which mainly plays the role of sound insulation and support.

[0048] Specifically, the following analysis is conducted based on the sound absorption performance target (noise reduction coefficient ≥ 0.60), using the acoustic transfer matrix method or equivalent circuit theory. Theoretically, to achieve efficient sound absorption in a wide frequency band from 250Hz to 2000Hz, the relative acoustic impedance of the transparent sound-absorbing panel should be as close to 1.0 as possible, while the relative acoustic impedance should be as close to zero as possible.

[0049] Based on the requirements for light transmission and mechanical properties, the material and preliminary geometric dimensions of the large-hole substrate are selected. A high-strength, high-light-transmittance material is chosen as the substrate material; for example, polyester, polycarbonate, acrylic polymers, polyurethane, and fluoropolymers can be selected. In one feasible embodiment, to meet the bending stiffness requirements, the initial thickness is determined to be 4 mm. To ensure ease of processing, light transmission, and structural stability, the initial aperture of the large holes is set to 5 mm, and the hole spacing to be 15 mm.

[0050] Material selection for the microslit membrane: A membrane with good weather resistance and high light transmittance should be chosen. For example, polyester film, fluoropolymer film, polycarbonate, polyolefin, and polyurethane film can be selected. In one feasible embodiment, the initial thickness is determined to be 0.1 mm. This thickness ensures sufficient strength while providing adequate acoustic impedance and low acoustic impedance over a wide frequency range, which is beneficial for achieving broadband sound absorption.

[0051] Determine the thickness of the sound insulation back panel. Based on the sound insulation performance requirements and the material of the back panel, the surface density and thickness of the sound insulation back panel can be determined. In one feasible implementation, the initial thickness of the sound insulation back panel is determined to be 8mm.

[0052] The depth D of the air acoustic cavity layer is determined. In one feasible implementation, based on the requirement that the total thickness is not less than 80 mm and not more than 100 mm, and considering the conditions that the thickness of the large-hole substrate is 4 mm, the thickness of the sound insulation back plate is 8 mm, and the thickness of the micro-slit film is negligible, the depth D of the air acoustic cavity layer is determined to be 60 mm after considering the overall structural design. The presence of the air acoustic cavity layer makes the structure a Helmholtz resonator system. The air inside the cavity acts like a spring, generating a restoring force on the air column inside the hole, which determines its frequency characteristics.

[0053] Based on the parameters of the aforementioned components, the acoustic impedance contributed by the large-hole substrate and the air acoustic cavity layer is theoretically calculated. To make the total acoustic impedance approach the target value, the target acoustic impedance required by the micro-slit film can be derived. According to acoustic theories such as micro-perforated substrates and micro-slit plates, the acoustic impedance of the microslit is mainly determined by the slit width, film thickness, number of slits, slit length, and perforation rate. Through calculation, the target acoustic impedance to be achieved is preliminarily determined to be: the slit width should be in the range of 0.05 mm to 0.15 mm, the film thickness should be in the range of 0.05 mm to 0.15 mm, and the perforation rate (i.e., the ratio of the total area of ​​the microslits to the total area of ​​the film) should be in the range of 0.5% to 2%.

[0054] After completing the theoretical estimation, the process proceeds to the numerical simulation and parameter optimization stage (S30). This stage utilizes multiphysics simulation software to perform precise numerical calculations and iterative optimization within the theoretically defined parameter range.

[0055] As an optional implementation method, the specific steps are as follows: Simulation Model S31: A three-dimensional numerical simulation model of a single periodic element of the transparent sound-absorbing panel was established using commercial finite element software. This model includes the micro-slit film and the large-pore substrate. Considering the significant energy loss caused by air viscosity and thermal conduction effects during sound wave propagation within the micro-slits, a thermoviscous acoustic frequency domain physics interface was used for solution in the simulation. This method can accurately describe the velocity gradient and temperature fluctuations of sound waves within the boundary layer, thereby accurately calculating the sound energy dissipation.

[0056] Iterative Calculation and Optimization S32: Within the theoretically estimated parameter range (e.g., slit width 0.05mm-0.15mm), parametric scanning and iterative optimization are performed. For example, all other geometric parameters are fixed (e.g., substrate thickness 4mm, aperture 5mm, cavity depth 60mm, film thickness 0.1mm), and only the slit width is used as a variable, starting from 0.05mm and scanning in 0.01mm increments. For each slit width value, the simulation software solves for performance parameters such as sound pressure, velocity, temperature, viscothermal energy loss distribution, and transmission impedance.

[0057] Simulations can reveal detailed physical field distributions within the structure, such as the velocity vectors of air particles near the microslits and the viscosity-thermal energy loss density. When sound waves are incident, most of the energy loss is concentrated in the narrow microslit region, where the velocity gradient is also the largest, confirming that the microslits are the primary acoustic energy dissipation components.

[0058] Through simulation calculations, the transmission impedance of the transparent sound-absorbing panel at different frequencies can be obtained. Combined with the impedance of the air acoustic cavity layer, the curve of the normal sound absorption coefficient of the transparent sound-absorbing screen as a function of frequency can be calculated. Based on this curve, the corresponding noise reduction coefficient can be predicted.

[0059] The predicted noise reduction coefficient is compared with the target value (noise reduction coefficient ≥ 0.60) set in the target design and index determination stage S10. If the target is not met, one or more geometric parameters (such as slit width, film thickness, slit length, number of slits, and slit spacing) are adjusted, and the simulation calculation is repeated. For example, if the predicted noise reduction coefficient is 0.55 when the slit width is 0.11 mm, the slit width is further reduced to 0.1 mm. After several iterations, the simulation results show that when the slit width is 0.1 mm and 7 micro-slits are etched on the film corresponding to each large hole, the predicted noise reduction coefficient reaches 0.65. This value meets the design target and leaves a certain design margin. Therefore, this set of parameters (polycarbonate substrate thickness 4 mm, hole diameter 5 mm, hole spacing 15 mm; ethylene-tetrafluoroethylene copolymer film thickness 0.1 mm, slit width 0.1 mm, number of slits 7; cavity depth 60 mm) is determined as a preferred combination of geometric parameters.

[0060] Accordingly, the process moves into the crucial experimental verification and feedback correction phase S40. This phase aims to verify the accuracy of the simulation results through the fabrication and testing of physical prototypes, and to establish closed-loop feedback to correct the model, thereby ensuring that the final product performance meets the standards.

[0061] This stage may include multiple steps: Prototype Fabrication S41: Based on the optimized geometric parameter combination from the previous step, the prototype is fabricated. Specifically, a polycarbonate large-hole substrate is processed using laser cutting or a CNC machine tool. A thin film is then laminated onto the fabricated substrate, and a high-precision scribing process is used to scribble a 0.1mm wide micro-slit on the film surface corresponding to the large holes in the substrate. It should be noted that this scribing process is lower in cost and less likely to generate a heat-affected zone compared to laser drilling, thus better ensuring the quality of the seam edges. Simultaneously, the feasibility of fabrication under this set of parameters is evaluated, and the deviation between the actual fabricated geometric dimensions and the design values ​​is recorded. For example, the measured seam width may be 0.1mm ± 0.005mm. This deviation information can be used for subsequent model correction.

[0062] Impedance tube testing S42: To quickly and accurately verify the effectiveness of the simulation model, the sound absorption performance under normal acoustic incidence is first tested. This embodiment uses the dual-microphone transfer function method conforming to international standards. A small-sized test sample (usually a circular sample with a diameter of 100mm) is installed at one end of the impedance tube, with a rigid end behind it, forming a cavity of a specific depth. For example, to match a standard sample, the cavity depth is adjusted to 60mm. A white noise signal is emitted from the sound source, and by measuring the sound pressure signals of the microphones at two fixed positions on the tube wall, the normal acoustic impedance and normal absorption coefficient of the test sample can be measured. In this embodiment, a Brüel & Kjær 4206 type impedance tube can be used for testing.

[0063] S43: Compare the simulation and experimental results: Compare the normal absorption coefficient curve measured by the impedance tube experiment with the curve calculated by the numerical simulation. In this embodiment, the two curves show good agreement at the center frequency of the 1 / 3 octave band within the 200Hz-1600Hz range, with an average relative error of less than 5%, which is less than the preset error threshold. This indicates that at this stage, the established numerical simulation model can accurately predict the acoustic behavior of the structure, and the model has been verified. Understandably, if the comparison results show a large error between the two (e.g., the resonant peak frequency shift exceeds 10%, or the peak absorption coefficient difference is greater than 15%), it indicates that the simulation model has failed to accurately reflect physical reality. At this time, a feedback correction loop must be initiated, returning to the numerical simulation and parameter optimization stage S30. The correction may include: checking and correcting the geometric parameters in the simulation model to make them consistent with the measured dimensions of the sample (rather than the ideal design values); adjusting the boundary conditions, mesh generation, etc. in the model; or correcting the physical model itself, for example, in some cases, it may be necessary to consider the influence of membrane vibration on sound absorption. In this way, the simulation model is continuously adjusted and recalculated until the simulation results are basically consistent with the experimental results.

[0064] Reverberation Chamber Test S44: After the simulation model is verified through impedance tube experiments, the final step, which is also the closest to the actual application scenario, is the performance verification. Based on the optimized geometric parameters, large-size prototypes meeting the application dimensions are fabricated. In this embodiment, 10 final screen prototypes with dimensions of 1960mm × 500mm × 80mm are fabricated. These prototypes are then arrayed and laid flat on the floor of the reverberation chamber. The reverberation chamber is a special room with a highly diffused sound field. Broadband noise is emitted through a dodecahedral omnidirectional sound source inside the room, and then the reverberation time change before and after placing the prototypes is measured using the interrupted source method. According to the Sabine formula, the sound absorption coefficient of the prototype under random incident sound field can be calculated, and the noise reduction coefficient can be obtained. NRC The tests in this embodiment were conducted at a temperature of 15.0°C and a relative humidity of 29%.

[0065] Comparison of Actual Measured Results with Target Results S45: The final performance indicators obtained from the actual measurements of the reverberation chamber are compared with the target values ​​set in the target determination stage S10. The measured results in this embodiment are: a noise reduction coefficient of 0.60. Specifically, the measured noise reduction coefficient value (0.60) reaches the preset target value (≥0.60). Simultaneously, the light transmittance, sound insulation performance, and bending stiffness of the sample were also tested, and the results all met the design requirements. Thus, the entire design process is successfully closed, declaring the successful design of this high-performance transparent sound-absorbing screen.

[0066] Understandably, if the final measured noise reduction coefficient fails to meet the target (e.g., a measured value of 0.55), a deeper feedback loop needs to be initiated. At this point, the process returns to the numerical simulation and parameter optimization step S30 to analyze the reasons for the deviation (which could be due to accumulated errors in manufacturing precision, large size effects, etc.) and adjust the optimization strategy. For example, a higher target value (e.g., noise reduction coefficient ≥ 0.70) might be set during simulation optimization to increase design redundancy. Then, the subsequent simulation, prototype fabrication, testing, and verification processes are repeated until the final product's measured performance fully meets all design objectives.

[0067] This embodiment demonstrates, through a complete case study, how the method of this application can systematically and accurately complete the design of a complex acoustic product with multiple objectives and multiple physical field coupling. Its core lies in the close integration of theory, simulation and experiment, as well as the key closed-loop feedback correction mechanism.

[0068] Example 3 like Figure 1As shown, based on Embodiment 1, according to the present invention, a method for manufacturing a transparent sound-absorbing screen includes a preferred process of perforating a transparent plate to form a transparent perforated substrate: preheating / stress relief of the plate; positioning and clamping: vacuum + edge clamping / adhesive spraying, flat and without warping; tool setting + compensation: Z-axis depth + XY offset compensation; trial drilling of 1-2 holes: checking hole position, hole diameter, hole opening, and burrs; batch processing: timed tool changing, spot inspection, and chip removal; post-processing: deburring, cleaning, and inspection.

[0069] In a preferred micro-slit processing method: dust removal and static electricity removal; flat laying → uniform vacuum adsorption; CCD vision grasping and positioning reference; automatic focusing → engraving micro-slits; trial processing → confirming slit width, slit length, and edge condition; first piece qualified → batch processing; real-time dust removal → finished product inspection.

[0070] In a preferred back panel cutting process: first piece qualified → batch cutting; deburring, inspection, and sorting.

[0071] In a preferred machining process for frame profiles: thread tapping (uniform speed, forward direction, and timely chip removal); deburring, cleaning, and inspection.

[0072] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0073] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for manufacturing a transparent sound-absorbing screen, characterized in that, The methods include: Transparent sound-absorbing panel preparation: A transparent perforated substrate is formed by perforating a transparent plate, a transparent film is attached to the transparent perforated substrate, and micro-slits are formed on the transparent film at the holes of the transparent perforated substrate to obtain the transparent sound-absorbing panel. Transparent sound insulation back panel preparation: Transparent sheet material is cut to form a transparent sound insulation back panel; Border preparation: The border is formed by machining; Finished product assembly: The sound-absorbing panel and the sound-insulating back panel are installed on the frame. The sound-absorbing panel and the sound-insulating back panel are set at a distance from front to back and form an air acoustic cavity layer. The frame is installed around the sound-absorbing panel and the sound-insulating back panel with fasteners to form a transparent sound-absorbing screen finished product.

2. The method for manufacturing a transparent sound-absorbing screen according to claim 1, characterized in that, The processing geometry parameters of the transparent perforated substrate, transparent micro-slit film, air acoustic cavity layer, and transparent sound insulation back panel are obtained through calculation, including the following steps: S10, Target Design and Index Determination Stage: Determine the target design values ​​for the sound absorption performance, sound insulation performance, light transmission performance, mechanical performance, and structural size requirements of a transparent sound-absorbing screen, and preset the error threshold for comparing experimental and simulation results. S20. In the theoretical analysis and parameter estimation stage, using acoustic theory and empirical models, and in conjunction with the target design values, the range of variation of the geometric parameters of each component constituting the transparent sound-absorbing screen is initially calculated and determined. S30. In the numerical simulation and parameter optimization stage, within the range of variation of the geometric parameters, multiphysics simulation software is used to perform numerical simulation and iterative optimization on the transparent sound-absorbing screen until the simulated sound absorption performance requirements, sound insulation performance requirements, light transmission performance requirements, mechanical performance requirements and structural size requirements all meet the target design values, thereby determining an optimal combination of geometric parameters. S40. Experimental Verification and Feedback Correction Stage: Based on the preferred geometric parameters, a sample is fabricated and its acoustic, light transmission, and mechanical properties are tested. The experimental test results are compared with the numerical simulation results. If the difference between the experimental test results and the simulation results is greater than a preset threshold, or if the sound absorption performance, light transmission performance, and mechanical properties in the experimental test results do not all meet the target design values, then the numerical simulation and parameter optimization stage is returned to correct the physical model, model parameters, or boundary conditions used in the numerical simulation, or the geometric parameters are adjusted and iterated repeatedly until the measured sound absorption performance, light transmission performance, and mechanical properties of the sample all meet the target design values.

3. The method for manufacturing a transparent sound-absorbing screen according to claim 2, characterized in that, For S10, the target design values ​​for the transparent sound-absorbing screens on both sides of the traffic route include: Sound absorption performance requirements: The noise reduction coefficient (NRC) of the screen shall not be less than 0.60; Sound insulation performance requirements: weighted sound insulation of the screen R w Not less than 30dB; Light transmittance requirements: The visible light transmittance of the screen shall not be less than 70%; Mechanical performance requirements: The bending stiffness of the sound-absorbing panel shall not be less than 4 N·m; Structural dimensional requirements: The total thickness of the screen body shall not exceed 100mm; Error threshold setting: The average relative error should be less than 5%.

4. The method for manufacturing a transparent sound-absorbing screen according to claim 2, characterized in that, For S20, the following steps are included: S21. Based on the sound absorption performance requirements and structural dimension requirements, estimate the maximum sound absorption coefficient under the normal incident direction of the sound wave in reverse. α max Resonant absorption frequency f 0 and effective sound absorption frequency range f UL The optimal range, initially determining the effective range of the product's acoustic impedance, and the effective sound absorption frequency band. f UL This refers to the ratio of the upper limit to the lower limit of the effective sound absorption frequency. S22. Based on the product's light transmittance requirements, preliminarily determine the materials for the transparent perforated substrate, transparent film, and sound insulation back panel; S23. Based on the mechanical performance requirements of the product, the thickness of the transparent perforated substrate is initially estimated, and the effective range of the hole diameter and hole spacing of the transparent perforated substrate is initially determined based on the ease of processing, light transmittance and structural stability. S24. Based on the effective range of the thickness, aperture and spacing of the transparent perforated substrate determined in the previous step, calculate the acoustic impedance contributed by the transparent perforated substrate. S25. Based on the sound insulation performance requirements of the product and the material of the sound insulation back panel determined in S22, determine the surface density and thickness of the sound insulation back panel. S26. Based on the total thickness, the thickness of the transparent perforated substrate and the transparent sound insulation backing, determine the thickness of the air acoustic cavity layer, and then calculate the acoustic impedance contributed by the air acoustic cavity layer. S27. Based on the effective range of acoustic impedance determined in S21, the acoustic impedance contributed by the transparent perforated substrate determined in S24, and the acoustic impedance contributed by the air acoustic cavity layer determined in S26, calculate and determine the effective range of acoustic impedance of the micro-slit film. S28. Based on the effective range of acoustic impedance of the micro-slit film determined in the previous step, preliminarily estimate the range of variation of geometric parameters such as the thickness of the transparent film, the width of the micro-slit, and the perforation rate.

5. The method for manufacturing a transparent sound-absorbing screen according to claim 2, characterized in that, For S30, the following steps are also included: S31. Establish a simulation model. Use commercial finite element software to establish a three-dimensional numerical simulation model of a single periodic unit of the transparent sound-absorbing screen. The transparent sound-absorbing screen is formed by the combination of a transparent sound-absorbing panel and a transparent sound-insulating back panel. S32. Within the theoretically estimated parameter range, perform parametric scanning and iterative optimization, fix all other geometric parameters, and use only one geometric parameter as a variable to scan with a preset step size, and simulate and solve the sound pressure, velocity, temperature, viscothermal energy loss distribution and transmission impedance.

6. The method for manufacturing a transparent sound-absorbing screen according to claim 2, characterized in that, Step S40 includes the following steps: S41. Based on the geometric parameter combination in step S30, process and manufacture small-sized impedance tube samples; S42. Perform impedance tube testing to test the sound absorption performance under normal incident sound wave inside the impedance tube. S43. Comparing the simulation and experimental results, if the average relative error is less than 5%, it indicates that the numerical simulation model established at this stage can accurately predict the acoustic behavior of the structure, and the model has been verified. If the average relative error is not less than 5%, it indicates that the simulation model has failed to accurately reflect the physical reality. The feedback correction loop is initiated, and the simulation returns to the numerical simulation and parameter optimization stage S30. S44. Conduct reverberation chamber testing. Based on the geometric parameters of the verified model, fabricate a large-size prototype that meets the application dimensions and test it in the reverberation chamber to obtain the final performance indicators. S45. Compare the noise reduction coefficient obtained by actual measurement in the reverberation chamber with the target design value of sound absorption performance set in the target design and index determination stage S10. If the target design value is met, the standard is met. S46. Conduct tests on sound insulation performance, light transmittance performance, mechanical performance, etc., to obtain performance indicators such as weighted sound insulation, visible light transmittance, and bending stiffness. Compare these with the target design values ​​set in the target design and indicator determination stage S10. If the target design values ​​are met, the standard is met. If the target design value is not met, return to the numerical simulation and parameter optimization stage S30 to check and correct the geometric parameters in the simulation model, and then repeat the subsequent simulation, prototype manufacturing, testing and verification process until the actual performance of the final product meets the target design value.

7. The method for manufacturing a transparent sound-absorbing screen according to claim 1, characterized in that, The process of creating micro-slits on a transparent thin film corresponding to the holes in a transparent perforated substrate includes laser cutting or mechanical scribing.

8. The method for manufacturing a transparent sound-absorbing screen according to claim 1, characterized in that, The slit width processed on the transparent film should be in the range of 0.05mm to 0.15mm, and the perforation rate should be in the range of 0.5% to 2%.

9. The method for manufacturing a transparent sound-absorbing screen according to claim 1, characterized in that, Transparent films are made of materials including polyester film, fluoropolymer film, polycarbonate, polyolefin, and polyurethane film; The materials used for transparent perforated substrates and sound-insulating back panels include polyester, polycarbonate, acrylic polymers, polyurethane, and fluoropolymers.

10. A transparent sound-absorbing screen, characterized in that, The method for manufacturing a transparent sound-absorbing screen according to any one of claims 1 to 9 includes a sound-absorbing panel and a sound-insulating back panel arranged at intervals, an air acoustic cavity layer being formed between the sound-absorbing panel and the sound-insulating back panel, and a frame being installed around the sound-absorbing panel and the sound-insulating back panel.

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