A passive front cavity structure based on planar sound field and its manufacturing method

Abstract

This invention discloses a passive front cavity structure based on a planar sound field and its manufacturing method, relating to the field of musical glass technology. It solves the problem of pit traps and includes a metasurface crystal layer with a driving structure and a passive cavity on it. The driving structure and the metasurface crystal layer form a superconducting surface for sound generation. The passive cavity includes several arrayed front cavity structures, each comprising a sound conductor and a plastic magnetic film. The sound conductor surrounds the cavity structure, which has an air inlet and an air outlet. The plastic magnetic film serves as the acoustic cavity cover. This results in a smoother FR curve, reduced THD, and eliminated noise, achieving improved sound quality from a planar sound source. It better meets the needs of new energy vehicles for low power consumption, thinner design, and lighter weight, presenting a completely new audio experience and giving car audio systems a new and powerful effect.

Description

Technical Field

[0001] This invention relates to the field of musical glass technology, and in particular to a passive front cavity structure based on a planar sound field and its manufacturing method. Background Technology

[0002] Musical glass is a new type of professional audio product that can be integrated into any automotive glass, providing customers with a large-area, highly directive, highly reliable, and easier-to-tuned listening experience from top to bottom, left to right, and front to back. In the future, it will inevitably replace car stereos, achieving the goals of thinner and lighter designs, and delivering a stunning new sound source experience and cutting-edge technology. However, because automotive glass, such as sunroofs and windshields, is relatively thick and has a laminated structure, its front-rear (FR) performance curve has multiple indentations, creating multiple sound wave traps that complement the glass's inherent modes. Furthermore, musical glass is a large-area surface sound source; the increased THD at the FR indentations causes significant noise interference. Summary of the Invention

[0003] The purpose of this invention is to provide a passive front cavity structure based on a planar sound field, which solves the pit trap problem, makes the FR curve smoother, reduces THD, eliminates noise, improves the sound quality of the surface sound source, and provides a brand-new Hi-Fi effect. This better meets the needs of new energy vehicles for low power consumption, thinning, and weight reduction, presents a brand-new audio experience, and gives car audio a brand-new shock effect.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A passive front cavity structure based on a planar sound field includes a metasurface crystal layer, a driving structure and a passive cavity on the metasurface crystal layer, the driving structure and the metasurface crystal layer form a superconducting surface for sound generation, the passive cavity includes several front cavity structures arranged in an array, the front cavity structure includes a sound conductor and a plastic magnetic film, the sound conductor surrounds the cavity structure, and the cavity structure is provided with an air inlet and an air outlet, the plastic magnetic film is the sound cavity cover of the front cavity.

[0005] Furthermore, a resonant absorption layer is provided between the metasurface crystal layer and the driving structure, which absorbs excess resonant force.

[0006] Furthermore, a superconducting buffer layer is provided between the acoustic conductor and the plastic magnetic film.

[0007] Furthermore, a superconducting buffer layer is also provided between the metasurface crystal layer and the acoustic conductor.

[0008] Furthermore, the superconducting buffer layer is viscous, serving as an intermediate layer for bonding and shock absorption.

[0009] Furthermore, the metasurface crystal layer and the acoustic conductor are further fixed together by an acrylic adhesive layer.

[0010] Furthermore, the acrylic adhesive layer is formed by curing acrylic liquid by irradiation with a light source.

[0011] Furthermore, the acoustic conductor includes a phononic crystal and a localized resonant structure.

[0012] Furthermore, the plastic magnetic film is formed by processing rare earth permanent magnets into powder, then compressing them into a film structure through processing, and finally smoothing the surface.

[0013] This invention also provides a method for manufacturing a passive front cavity structure based on a planar sound field, comprising the following steps: A driving structure is installed on the metasurface crystal layer. The position, size, and number of passive cavities are determined on the metasurface crystal layer. Based on the size of the passive cavities, the acoustic conductor is bonded to the acoustic conductor through a superconducting buffer layer. Then, a plastic magnetic film is bonded to the acoustic conductor through another superconducting buffer layer to form a passive cavity. Finally, the acoustic conductor and the metasurface crystal layer are fixed a second time through an acrylic adhesive layer.

[0014] In summary, the present invention has the following beneficial effects: During normal operation, the active drive device drives the passive cavity to move, increasing low-frequency resonance through the passive cavity. This, combined with the acoustic conductor and other aspects, improves the frequency response of the music glass, indirectly enhancing frequency response performance and harmonic distortion. This eliminates noise, improves the sound quality of the surface sound source, and creates a brand-new Hi-Fi effect, giving car audio a completely new and stunning experience. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of a passive front cavity structure based on a planar sound field according to the present invention; Figure 2 This is a schematic diagram of the connection between the driving structure and the metasurface crystal layer in a passive front cavity structure based on a planar sound field according to the present invention. Figure 3 This is a schematic diagram of the phonon crystal portion in a passive front cavity structure based on a planar sound field according to the present invention; Figure 4 This is a schematic diagram of the front cavity structure portion in a passive front cavity structure based on a planar sound field according to the present invention; Figure 5 This is a schematic diagram of the arrangement of the front cavity structure in a passive front cavity structure based on a planar sound field according to the present invention; Figure 6 This is a schematic diagram illustrating the manufacturing method of the front cavity structure in a passive front cavity structure based on a planar sound field according to the present invention.

[0016] In the figure, 1 is the metasurface crystal layer; 2 is the driving structure; 3 is the passive cavity; 31 is the front cavity structure; 311 is the acoustic conductor; 312 is the air inlet; 313 is the air outlet; 4 is the plastic magnetic film; 5 is the resonant absorption layer; 6 is the superconducting buffer layer; and 7 is the acrylic adhesive layer. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. These embodiments do not constitute a limitation of the present invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this application.

[0018] A passive front cavity structure based on a planar sound field, such as Figure 1 As shown, it includes a metasurface crystal layer 1, a driving structure 2 and a passive cavity 3 connected on the same side of the metasurface crystal layer 1. The driving structure 2 can be a linear motor, piezoelectric ceramic or exciter, and forms a superconducting surface for sound generation with the metasurface crystal layer 1. The passive cavity 3 includes several arrayed front cavity structures 31. Each front cavity structure 31 includes an acoustic conductor 311 and a plastic magnetic film 4. The acoustic conductor 311 forms a cavity structure, and the cavity structure is provided with an air inlet 312 and an air outlet 313. The plastic magnetic film 4 is the acoustic cavity cover of the front cavity, which is placed on the upper side of the cavity formed by the acoustic conductor 311, leaving only the air inlet 312 and the air outlet 313. A superconducting buffer layer 6 is provided between the acoustic conductor 311 and the plastic magnetic film 4, and between the metasurface crystal layer 1 and the acoustic conductor 311. The superconducting buffer layer 6 has adhesive properties and serves as an intermediate layer for bonding and shock absorption. The superconducting buffer layer 6 is an ultra-thin transparent material with adhesive properties on the surface of the acoustic conductor 311. It is directly attached to the surface of the acoustic conductor 311 and mainly plays an adhesive role to ensure that the front cavity structure 31 is flat and well-fitted.

[0019] like Figure 1 As shown, the metasurface crystal layer 1 and the acoustic conductor 311, and the acoustic conductor 311 and the plastic magnetic film 4 are further fixed by an acrylic adhesive layer 7; the acrylic adhesive layer 7 is formed by curing acrylic liquid by irradiation with a light source, and the acrylic liquid is used to fix the front cavity and the metasurface crystal in a secondary manner. Specifically, at the positions of acoustic conductor 311, superconducting buffer layer 6 and metasurface crystal layer 1, acrylic liquid is used for centered bonding on the outside, with the acrylic liquid in dots, for front-to-back bonding and firm fixation; at the positions of acoustic conductor 311, superconducting buffer layer 6 and plastic magnetic film 4, acrylic liquid is used for centered bonding on the outside, with the acrylic liquid in dots, for left-to-right bonding to ensure firm fixation.

[0020] like Figure 1As shown, the metasurface crystal layer 1 is a two-dimensional metacrystalline material constructed from a series of planar artificial atoms arranged in a specific manner. Its surface is smooth and flat, with good light transmittance and conductivity. By precisely designing the artificial atoms at different positions in the plane, the metasurface can have arbitrary electromagnetic wave reflection / transmission phase distribution, thereby achieving free and efficient control of the electromagnetic wave wavefront, ensuring stable and reliable sound wave transmission with low loss. In addition, compared with traditional three-dimensional metamaterials, metasurface crystal layer 1 has advantages such as low loss, easy integration and simple fabrication process, and can be used as a diaphragm carrier for passive front cavity.

[0021] like Figure 2 As shown, a resonant absorption layer 5 is connected between the metasurface crystal layer 1 and the driving structure 2, and the resonant absorption layer 5 absorbs excess resonant force. The driving structure 2 refers to the power unit structure on the metasurface crystal layer 1; by using acoustic simulation technology, the driving components are placed on the metasurface crystal layer 1 to form a superconducting surface sound generation technology. The above simulation technology is existing technology and will not be elaborated on here. A resonant absorption layer 5 is placed between the driving components and the metasurface crystal layer 1 to absorb excess resonant force and ensure smooth transmission of superconducting surface acoustic waves. The terminals of the driving components do not contact the metasurface crystal layer 1. By changing the connection method, multiple individual driving modules are formed. Each individual driving module is ultimately driven by a unified system to form the final driving structure 2, enabling the metasurface crystal layer 1 to smoothly transmit audio.

[0022] like Figure 3 As shown, the acoustic conductor 311 is composed of a phononic crystal and a localized resonant structure. Phononic crystals are a novel type of functional material formed by periodically arranging elastic solids within another solid or fluid medium. They utilize the unique elastic properties of sound waves during transmission. When elastic waves propagate within a phononic crystal, their propagation is inhibited within a certain frequency range (bandgap) due to the internal structure, while they can propagate without loss in other frequency ranges (passband). When defects exist in the periodic structure of a phononic crystal, elastic waves within the bandgap frequency range will be localized at the defect or propagate along the defect. Furthermore, phononic crystals can be used to control the propagation of elastic waves, playing a role in vibration reduction and noise reduction, ensuring stability during sound wave transmission.

[0023] The localized resonant structure is arranged in a cubic lattice within the epoxy resin matrix. Within this structure, the epoxy resin encapsulates relatively hard phonon crystals, forming a low-frequency resonant unit. This epoxy resin material possesses excellent flame retardancy, high-temperature resistance, waterproofing, shock absorption, sealing, heat insulation, UV resistance, ozone resistance, and good resistance to compressive deformation and creep.

[0024] like Figure 4 As shown, the front cavity structure 31 is a cavity structure designed using a sound conductor 311, and has multiple cavities arranged in a regular pattern. First, a superconductor is used to seal both sides of the front cavity. An air inlet 312 is designed at the top of the front cavity to ensure that air from the outside can easily enter, increasing the aerodynamic thrust of the internal cavity. An air outlet 313 is designed at the bottom of the cavity, from which gas is discharged when the edge is compressed. In addition, to ensure the stability of the cavity during transportation, a certain gap needs to be left at the top and bottom to play a stabilizing role. The air inlet and outlet structure can be designed to be flat or inclined depending on the airflow size. In this embodiment, the inner side of one acoustic conductor 311 is vertically connected to two parallel sides facing the other acoustic conductor 311. The gap between the two sides and the other acoustic conductor 311 forms an air inlet 312 and an air outlet 313. An inclined baffle is also connected to the inner side of the other conductor 311 at the position inside the air outlet 313 (making the two as a whole C-shape and V-shape), which guides the airflow to an inclined state.

[0025] like Figure 5 As shown, after completing the design of a single front cavity, multiple front cavities are arranged in a regular equidistant array using passive cavity 3 simulation technology. The low-frequency resonant harmonic power is increased through multiple passive front cavities, and the low-frequency pit enhances the low-frequency effect.

[0026] like Figure 1 As shown, the plastic magnetic film 4 is made by processing rare earth permanent magnets into powder, then compressing them into a film structure through processing, and smoothing the surface. The plastic magnetic film 4 is a rare earth permanent magnet material with a certain degree of magnetism. It is made by processing rare earth permanent magnets into powder, then compressing them into a film structure through processing, and smoothing the surface. The plastic magnetic film 4 is mainly used as the acoustic chamber cover of the front cavity. It is directly attached to the front cavity design and used on the outermost side, and its size is consistent with the size of the front cavity structure 31. It has the advantages of extremely high magnetic energy product and coercivity, as well as high energy density.

[0027] This embodiment also discloses a method for manufacturing a passive front cavity structure based on a planar sound field, such as... Figure 6 As shown, it can be widely used in sunroofs, windshields, and other glass components of rail transit vehicles. The functions involved include a metasurface crystal layer 1, a driving structure 2, a passive cavity 3, a sound conductor 311, a front cavity design, a plastic magnetic film 4, a superconducting buffer layer 6, and an acrylic adhesive design; the process includes the following steps: Based on the skylight, the position of the metasurface crystal structure on the skylight is determined by simulation and other methods. The position of the driving structure 2 on the metasurface crystal layer 1 is determined by simulation and other methods. The design and installation of the driving structure 2 are then completed. The position, size and number of passive cavities 3 are determined on the metasurface crystal layer 1 through methods such as passive cavity 3 simulation (the position of passive cavity 3 on the metasurface crystal surface is finally determined through cavity simulation and other methods, so as to complete the fabrication of passive cavity 3 in the determined position area). The structure and size of acoustic conductor 311 are designed according to the size of passive cavity 3, and the design of passive cavity 3 is completed. This embodiment specifically includes: After dividing the metasurface crystal layer 1 into several regions, the vibration of the surface acoustic field was measured using a test integrated machine and an amplitude sensor probe. The measured vibration data were arranged, and upper and lower limits of the vibration were set based on the maximum and minimum sound pressure values. The curve regions that exceeded the upper and lower limits were selected, and the number of passive cavities 3 was determined based on them. Among them, the number of passive cavities 3 in the part where the vibration exceeds the upper limit can be multiple, while the number of passive cavities 3 in the part where the vibration exceeds the lower limit does not exceed 2; secondly, the passive cavity 3 in the area with larger vibration is smaller in volume, and vice versa in the area with smaller vibration is larger in volume. Next, the surface sound field frequency response curve test is carried out to find the corresponding values ​​of f1 and f2, calculate the Q value, and then verify the force resistance of the vibration system, thereby determining the volume of the passive cavity 3, reducing the force resistance of the plane, and ensuring the smooth vibration of the plane. Finally, in the planar region exceeding the upper and lower limits of vibration, with the center line of this region as the center point, avoiding the position of the components, and based on the maximum diagonal size of the components as the diameter, the area outside the circle covered by the diameter is set to meet the above requirements for the number and volume of passive cavities 3; after multiple passive cavities 3 are arrayed, their symmetry is ensured. According to the design of the passive cavity 3, the acoustic conductor 311 is bonded to the metasurface crystal layer 1 through a superconducting buffer layer 6; then, a plastic magnetic film 4 is bonded to the acoustic conductor 311 through another superconducting buffer layer 6 to form the passive cavity 3 (if there are multiple passive diaphragms, they will form a certain array with a regular arrangement). Finally, the acoustic conductor 311 and the metasurface crystal layer 1, and the acoustic conductor 311 and the plastic magnetic film 4 are fixed on the outside by an acrylic adhesive layer 7.

[0028] When operating normally, the active drive device moves the passive cavity 3, increasing low-frequency resonance through the passive cavity 3. This, combined with the acoustic conductor 311 and other components, improves the frequency response of the music glass, indirectly enhancing frequency response performance and harmonic distortion. Noise disappears, the sound quality of the surface sound source is improved, presenting a completely new audio experience and giving car audio a stunning new effect.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the scope of its essence and protection. Such modifications or equivalent substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. A passive front cavity structure based on a planar sound field, characterized in that: It includes a metasurface crystal layer, on which a driving structure and a passive cavity are provided. The driving structure and the metasurface crystal layer form a superconducting surface for sound generation. The passive cavity includes several arrayed front cavity structures. The front cavity structure includes an acoustic conductor and a plastic magnetic film. The acoustic conductor surrounds the cavity structure, and the cavity structure is provided with an air inlet and an air outlet. The plastic magnetic film is the acoustic cavity cover of the front cavity.

2. The passive front cavity structure based on a planar sound field according to claim 1, characterized in that: A resonant absorption layer is provided between the metasurface crystal layer and the driving structure, which absorbs excess resonant force.

3. The passive front cavity structure based on a planar sound field according to claim 1, characterized in that: A superconducting buffer layer is provided between the acoustic conductor and the plastic magnetic film.

4. The passive front cavity structure based on a planar sound field according to claim 1, characterized in that: A superconducting buffer layer is provided between the metasurface crystal layer and the acoustic conductor.

5. A passive front cavity structure based on a planar sound field according to claim 3 or 4, characterized in that: The superconducting buffer layer is viscous and serves as an intermediate layer for bonding and shock absorption, providing initial fixation between the metasurface crystal layer and the acoustic conductor.

6. The passive front cavity structure based on a planar sound field according to claim 5, characterized in that: The metasurface crystal layer and the acoustic conductor are further fixed together by an acrylic adhesive layer.

7. A passive front cavity structure based on a planar sound field according to claim 6, characterized in that: The acrylic adhesive layer is formed by curing acrylic liquid by irradiation with a light source.

8. The passive front cavity structure based on a planar sound field according to claim 1, characterized in that: The acoustic conductor includes phononic crystals and localized resonant structures.

9. The passive front cavity structure based on a planar sound field according to claim 1, characterized in that: The plastic magnetic film is made by processing rare earth permanent magnets into powder, then compressing them into a film structure through processing, and finally smoothing the surface.

10. A method for manufacturing a passive front cavity structure based on a planar sound field, characterized in that: Includes the following steps, A driving structure is installed on the metasurface crystal layer. The position, size, and number of passive cavities are determined on the metasurface crystal layer. Based on the size of the passive cavities, the acoustic conductor is bonded to the acoustic conductor through a superconducting buffer layer. Then, a plastic magnetic film is bonded to the acoustic conductor through another superconducting buffer layer to form a passive cavity. Finally, the acoustic conductor and the metasurface crystal layer are fixed a second time through an acrylic adhesive layer.

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