Active acoustic metamaterial

Abstract

The invention discloses an active acoustic metamaterial. The active acoustic metamaterial is composed of a plurality of acoustic barrier units, each acoustic barrier unit comprises a plurality of functional surfaces, and a polyhedron is defined by the functional surfaces; and the plurality of functional surfaces comprise a transparent glass surface, a transparent micro-perforated plate surface and a film acoustic metamaterial surface. The transparent glass surface, the transparent micro-perforated plate surface and the film acoustic metamaterial surface are combined to form a polyhedron, the polyhedron can be used as a basic unit of an acoustic barrier, and the basic unit integrates multiple functions of light transmission, passive sound absorption, active sound absorption, shading and the like. When a plurality of basic units are combined together to be used for the acoustic barrier, on-demand configuration of barrier performance can be achieved, and adaptability and application value of products are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acoustic engineering, in particular to an active acoustic metamaterial. BACKGROUND

[0002] In modern architecture, transportation and industrial fields, the control of acoustic environment is put forward with higher and higher requirements. In acoustic engineering, various sound insulation materials (glass curtain wall, partition wall) and sound absorption materials (such as porous foam, perforated plate) are usually used to control noise. With the improvement of people's pursuit of the quality of living and working environment, single-function acoustic products have been difficult to meet the complex application requirements, for example, in open office, conference room or home environment, people need both daylighting and visual transparency in the daytime, and also need quiet acoustic environment and visual privacy at certain time.

[0003] At present, users need to install multiple independent systems (such as glass partition, sound absorption panel, curtain) to meet the requirements of daylighting, sound absorption, shading and other requirements, which occupies space and is high in cost. There is no solution in the prior art to integrate transparent, shading, passive sound absorption and active sound absorption through a single reconfigurable mechanical structure.

[0004] Therefore, the prior art still needs further research and improvement. SUMMARY

[0005] In order to solve the above technical problems, the present application provides an active acoustic metamaterial, which aims to solve the problem of single function and fixed performance of the acoustic barrier in the prior art. Specifically:

[0006] In a first aspect, an active acoustic metamaterial is provided, wherein the active acoustic metamaterial comprises a plurality of acoustic barrier units; the acoustic barrier unit comprises a plurality of functional surfaces, which enclose a polyhedron;

[0007] The plurality of functional surfaces comprises a transparent glass surface, a transparent micro-perforated plate surface and a thin film acoustic metamaterial surface;

[0008] The thin film acoustic metamaterial surface comprises a light-tight substrate, a flexible film tensioned on the light-tight substrate, and an active device arranged on or behind the flexible film; the thin film acoustic metamaterial surface combines active noise control principle with acoustic metamaterial structure design, and actively regulates the acoustic impedance of the surface of the acoustic metamaterial through the active device.

[0009] The following is a preferred technical solution of the present application, but not as a limitation to the technical solutions provided by the present application. Through the following preferred technical solution, the purpose and beneficial effects of the present application can be better achieved and realized.

[0010] As a preferred technical scheme, the active acoustic metamaterial, wherein the plurality of functional surfaces further comprise a high-reflection surface, an acoustic diffusion surface and a display screen surface.

[0011] As a preferred technical scheme, the active acoustic metamaterial, wherein the polyhedron comprises a triangular prism.

[0012] As a preferred technical scheme, the active acoustic metamaterial, wherein the active acoustic metamaterial comprises:

[0013] Frame:

[0014] A plurality of rotatable acoustic barrier units arranged side by side in the frame;

[0015] A rotation driving mechanism matched with the acoustic barrier units and arranged at one end of the acoustic barrier units for driving the acoustic barrier units.

[0016] A pivot arranged at the other end of the acoustic barrier units in cooperation with the rotation driving mechanism.

[0017] As a preferred technical scheme, the active acoustic metamaterial, wherein the rotation driving mechanism drives the plurality of acoustic barrier units to rotate synchronously, and the same functional surfaces on each acoustic barrier unit face the same direction.

[0018] As a preferred technical scheme, the active acoustic metamaterial, wherein the rotation driving mechanism drives the plurality of acoustic barrier units to rotate asynchronously or independently, and part or all of the same functional surfaces on each acoustic barrier unit face different directions.

[0019] As a preferred technical scheme, the active acoustic metamaterial, wherein the two ends of the polyhedron are respectively provided with end covers; the rotation driving mechanism comprises a sliding rack, a gear matched with the sliding rack and a power source for providing power for the sliding rack; the gear is arranged on one of the end covers, and the pivot is arranged on the other end cover.

[0020] As a preferred technical scheme, the active acoustic metamaterial, wherein the transparent micro-perforated plate surface comprises a micro-perforated plate provided with uniformly distributed micro-holes; and the transparent micro-perforated plate surface and an air cavity formed inside the polyhedron jointly constitute a Helmholtz resonance sound absorption system.

[0021] As a preferred technical scheme, the active acoustic metamaterial, wherein the polyhedron is a regular triangular prism, and the end portions of the two sides of the frame for supporting and fixing the acoustic barrier unit are provided with geometric limiting portions, and the regular triangular prism is geometrically limited by the geometric limiting portions.

[0022] In a second aspect, an acoustic barrier system comprises a control device, a sensing device and the active acoustic metamaterial described above.

[0023] The control device is electrically connected with the rotary driving mechanism, and the sensing device is electrically connected with the control device.

[0024] The sensing device comprises a light sensor and a noise spectrum analyzer.

[0025] The control device controls the rotation angle of the optical barrier according to the light intensity and / or noise volume of the environment sensed by the sensing device.

[0026] Advantages: Compared with the prior art, the embodiment of the present application has the following advantages:

[0027] The transparent glass surface, the transparent micro-perforated plate surface and the active loudspeaker film surface are combined to form a polyhedron, which can be used as a basic unit of an acoustic barrier. The basic unit integrates multiple functions such as light transmission, passive sound absorption, active sound absorption and light shielding. A plurality of basic units are combined to form an active acoustic metamaterial, which can realize on-demand configuration of barrier performance when used as an acoustic barrier, and improve the adaptability and application value of the product. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 A three-prism acoustic barrier unit perspective view is provided for the embodiment of the present application.

[0030] Figure 2 Another perspective view of a three-prism acoustic barrier unit is provided for the embodiment of the present application.

[0031] Figure 3 A perspective view of an active acoustic metamaterial is provided for the embodiment of the present application (mode one).

[0032] Figure 4The active acoustic metamaterial three-dimensional view (mode two) provided in the embodiment of the present application;

[0033] Figure 5 The working schematic view of the rotary driving mechanism (remove the side plate) provided in the embodiment of the present application. DETAILED DESCRIPTION

[0034] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0035] As shown in Figure 1 and Figure 2 , the acoustic barrier unit 10 provided in the embodiment of the present application includes a transparent glass surface 110, a transparent micro-perforated plate surface 120 and a thin film acoustic metamaterial surface 130. The transparent glass surface 110, the transparent micro-perforated plate surface 120 and the thin film acoustic metamaterial surface 130 enclose a triangular prism, and each functional surface serves as a side of the triangular prism. It should be noted that, Figure 1 and Figure 2 show a triangular prism. In addition to the triangular prism, the triangular prism can also be a quadrangular prism or a hexagonal prism, and the corresponding functional surfaces can also be a high reflection surface (sound reflectivity greater than or equal to 90%), a sound diffusion surface and a display screen surface in addition to the above three. That is, it can be set as needed, and the polyhedron formed can be a regular polyhedron or an irregular polyhedron. In order to better explain and illustrate, the following mentioned are all regular polyhedrons, such as Figure 1 the regular triangular prism shown in

[0036] In the present embodiment, the three functional surfaces (transparent glass surface, transparent micro-perforated plate surface and thin film acoustic metamaterial surface) enclose a hollow triangular prism, and the two top ends of the triangular prism are provided with cover bodies 141 and 142. The gear 200 is arranged on the cover body 141, and the pivot 210 is arranged on the cover body 142. The gear 200 and the pivot 210 are located at the two ends of the rotation axis of the triangular prism.

[0037] In the present embodiment, the transparent glass surface 110 is made of a high-transmittance rigid material, such as tempered glass, laminated glass or polycarbonate plate. Its main function is to provide visual transparency and basic sound insulation performance, such as Figure 3Mode I. Transparent micro-perforated panel surface 120: This surface is composed of a transparent micro-perforated panel (MPP). The micro-perforated panel is uniformly distributed with micro-holes. The micro-perforated panel surface and the air cavity formed inside the triangular prism unit together form a Helmholtz resonance sound absorption system. When sound waves are incident, the sound energy is converted into heat energy through the viscous effect and heat conduction of the micro-holes, realizing passive broadband sound absorption. Thin film acoustic metamaterial surface 130: This surface is a composite structure composed of an opaque base panel (not shown), a flexible film 131 tensioned thereon, and an active device such as a loudspeaker 132 (as a driver) mounted on or behind the film. This surface combines active noise control principles with material structure design, actively regulating the acoustic impedance of the material surface through active devices such as loudspeakers, enabling "perfect absorption" of low-frequency sound waves with extremely thin thickness. In particular, the combination of loudspeakers and thin films forms a so-called "electro-acoustic sound absorber" or active thin film acoustic metamaterial, achieving ultra-thin, high-efficiency low-frequency sound absorption. The loudspeaker itself can absorb sound, and the loudspeaker acts as a mass block of the thin film acoustic metamaterial, utilizing the mass of the loudspeaker itself as a scatterer and forming a pure mechanical local resonance unit with the thin film, and utilizing the electromagnetic resonance unit formed by the shunt loudspeaker and the external damping circuit to form a new active thin film acoustic metamaterial noise reduction mechanism.

[0038] In addition, in the implementation, a shunt loudspeaker array can also be introduced into the thin film acoustic metamaterial to form a new active thin film acoustic metamaterial structure. Through active control, efficient absorption of specific frequency band (especially low frequency) noise is achieved, while also serving as a light shield and protecting privacy. It should be noted that the material of the flexible film 131 is a prior art and will not be limited or described here.

[0039] Based on the same inventive concept, the embodiments of the present application also provide an active acoustic metamaterial, as shown in Figure 3 and Figure 4 The active acoustic metamaterial includes a frame 40, a plurality of rotatable acoustic barrier units as described above arranged side by side in the frame 40, and a rotating drive mechanism 20 adapted to the acoustic barrier units and arranged at the same end of the acoustic barrier units to drive the acoustic barrier units. As an acoustic barrier, three triangular prism-shaped acoustic barrier units are included. The rotating drive mechanism drives the three acoustic barrier units to rotate in one direction through rack gear devices, belt devices, etc. Related equipment involved, such as power supply motors, gears, racks, belts, rollers, shafts, etc., are all existing technologies and will not be limited here.

[0040] In addition, it should be noted that this embodiment is only for explanation and the active acoustic metamaterial includes three acoustic barrier units, and the specific number of settings can be set as needed, such as five or six. Among them, Figure 3For mode one (transparent sound absorption mode), the barrier at this time is like a glass wall or window, ensuring the indoor lighting and visual connection between the indoor and outdoor space. Although the transparent micro-perforated panel surface and the active loudspeaker membrane surface are not directly facing the main sound source, they can still absorb the reverberation sound energy in the room or perform secondary absorption on the sound waves transmitted through the glass surface, thereby improving the overall acoustic environment. The micro-perforated panel surface and the air cavity behind it continue to play a passive sound absorption role (at this time, passive sound absorption) in this mode. Figure 4 For mode two (opaque strong sound absorption mode), the opaque membrane surface provides perfect light shielding effect and visual isolation, ensuring privacy. Activate the active sound absorption control module, and the controller (not shown) drives the loudspeaker to generate a compensation sound field. Through precise electro-acoustic control, the acoustic impedance of the barrier surface is actively adjusted, enabling near-perfect absorption of low-frequency noise (such as air conditioning, traffic noise) that traditional materials cannot handle. Users can also select the noise frequency band that needs to be focused on absorption through the controller according to their needs.

[0041] In this embodiment, the rotating drive mechanism 20 includes a sliding rack 201, a gear 202 matched with the sliding rack, and a power source (not shown) for providing power to the sliding rack. As shown in Figure 5 As shown, number ① is in the opaque strong sound absorption mode, at which time the loudspeaker surface forms a flat, continuous opaque barrier. Number ② is the gear driven by the rack to rotate the acoustic barrier unit, and when it is rotated to the state shown in number ③, the acoustic barrier unit is rotated by 60 degrees.

[0042] In this embodiment, the frame 40 is composed of four sides, and the end of the two sides for supporting and fixing the acoustic barrier unit is provided with a geometric limiting part 400, which realizes the geometric limiting of the right triangular prism. As shown in Figure 5 As shown, one side of the frame 40 close to the edge of the triangular prism is a straight edge, and the side opposite to it is an arc-shaped edge. During the rotation of the triangular prism, the edge of the triangular prism can pass through the arc-shaped edge but not the straight edge. Therefore, the straight edge can play a geometric limiting role in this process. As shown in Figure 5 As shown in number ③ in the above figure, the adjacent edges of the three triangular prisms are closely connected, and it is not easy to appear light leakage or sound leakage, which improves the shielding effect.

[0043] In the embodiment, the driving mode can be synchronous driving or asynchronous driving, and a separate micro motor (such as a stepper motor or a servo motor) can be provided for each triangular prism unit, and the central control system is uniformly coordinated. This mode can realize asynchronous or grouped rotation of the unit, form a mixed mode such as "partial light transmission and partial strong sound absorption", or form a specific pattern on the barrier surface, increasing the flexibility of design. In addition to the gear and rack mechanism, synchronous belt and synchronous wheel, multi-link mechanism or chain transmission mechanism can also be used to realize the synchronous rotation of all triangular prism units, and these modes can ensure the accuracy and synchronization of rotation.

[0044] The active acoustic metamaterial provided in the embodiment integrates multiple functions such as light transmission, sound insulation, passive sound absorption, active sound absorption, light shielding, privacy protection, etc. in a single device, has multiple functions for one object, saves space, and reduces the overall cost. Through simple mechanical rotation, it can be switched between "transparent" and "strong sound absorption" two very different functional modes, with high environmental adaptability. In the light shielding mode, the active acoustic metamaterial technology effectively solves the problem of low sound absorption efficiency of traditional sound absorption bodies in the low frequency band.

[0045] Based on the same inventive concept, the embodiment of the present application also provides an acoustic barrier system, comprising: a control device, a sensing device and an acoustic barrier; the control device is electrically connected with the rotating drive mechanism; the sensing device is electrically connected with the control device; the sensing device comprises a light sensor and a noise spectrum analyzer; the control device controls the rotation angle of the optical barrier according to the light intensity and / or noise volume sensed by the sensing device.

[0046] In the embodiment, by integrating the environmental sensor into the control system, automatic switching of the barrier mode is realized. For example, when the indoor noise exceeds the threshold value, it is automatically switched to the strong sound absorption mode. Further, the active sound absorption algorithm can be introduced into artificial intelligence, so that it can learn and adapt to complex noise environment independently.

[0047] Exemplarily, a high-sensitivity microphone array and a temperature and humidity sensor are arranged in a key area of a room to collect environmental noise level, spectral characteristics and environmental parameters in real time, and transmit data to a control. The central control unit presets a noise threshold (such as 55 dB(A)), and when it is detected that the indoor noise continuously exceeds the threshold, a control signal is automatically triggered to drive the adjustable acoustic structure (such as a variable porosity sound absorption panel or an adjustable Helmholtz resonator) to switch to a "strong sound absorption mode" to enhance the absorption capacity of the middle and low frequency noise. The system introduces an active sound absorption algorithm based on deep reinforcement learning. The algorithm is continuously trained through historical noise data and user feedback (such as comfort score), can identify noise types (such as traffic noise, human voice, equipment running sound), and predict the optimal sound absorption parameter configuration. For example, after identifying periodic traffic noise during morning and evening peak hours, the system can adjust the sound absorption structure state in advance to achieve proactive noise control.

[0048] It should be understood that the application is not limited to the precise construction which has been described above and illustrated in the accompanying drawings, and that various modifications and changes can be made without departing from the scope thereof. The only scope of the application is defined by the appended claims

[0049] The above description is merely the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An active acoustic metamaterial, characterized in that, The active acoustic metamaterial comprises several acoustic barrier units; The acoustic barrier unit includes several functional surfaces, which together form a polyhedron. The functional surfaces include: a transparent glass surface, a transparent micro-perforated plate surface, and a thin-film acoustic metamaterial surface; The thin-film acoustic metamaterial surface includes: an opaque substrate, a flexible thin film stretched on the opaque substrate, and an active device disposed on or behind the flexible thin film; the thin-film acoustic metamaterial surface combines the principle of active noise control with the structural design of acoustic metamaterials, and actively regulates the acoustic impedance of the acoustic metamaterial surface through active devices.

2. The active acoustic metamaterial according to claim 1, characterized in that, The functional surfaces also include a high-reflectivity surface, a sound-diffusing surface, and a display screen surface.

3. The active acoustic metamaterial according to claim 1, characterized in that, The polyhedron includes a triangular prism.

4. The active acoustic metamaterial according to claim 1, characterized in that, The active acoustic metamaterial includes: frame: Multiple rotatable acoustic barrier units are arranged side by side within the frame; A rotary drive mechanism, adapted to the acoustic barrier unit and disposed at the same end of the acoustic barrier unit, is used to drive the acoustic barrier unit. A pivot, which is configured in conjunction with the rotary drive mechanism, is located at the other end of the acoustic barrier unit.

5. The active acoustic metamaterial according to claim 4, characterized in that, The rotary drive mechanism drives the plurality of acoustic barrier units to rotate synchronously, with the same functional surfaces on each acoustic barrier unit facing the same direction.

6. The active acoustic metamaterial according to claim 4, characterized in that, The rotary drive mechanism drives the plurality of acoustic barrier units to rotate asynchronously or independently, with some or all of the same functional surfaces on each acoustic barrier unit facing different directions.

7. The active acoustic metamaterial according to claim 4, characterized in that, The polyhedron is provided with end caps at both ends; the rotary drive mechanism includes: a sliding rack, a gear matching the sliding rack, and a power source that provides power to the sliding rack; the gear is disposed on one of the end caps, and the pivot is disposed on the other end cap.

8. The active acoustic metamaterial according to claim 4, characterized in that, The transparent micro-perforated plate surface includes: a micro-perforated plate, wherein uniformly distributed micropores are provided on the micro-perforated plate surface; the transparent micro-perforated plate surface and the air cavity formed inside the polyhedron together constitute a Helmholtz resonance sound absorption system.

9. The active acoustic metamaterial according to claim 4, characterized in that, The polyhedron is a regular triangular prism. The frame is provided with a geometric limiting part to support and fix the ends of the two sides of the acoustic barrier unit, thereby achieving geometric limiting of the regular triangular prism.

10. An acoustic barrier system, characterized in that, include: Control device, sensing device, and the active acoustic metamaterial as described in claim 4; The control device is electrically connected to the rotary drive mechanism; the sensing device is electrically connected to the control device. The sensing device includes a light sensor and a noise spectrum analyzer; The control device controls the rotation angle of the optical barrier based on the ambient light intensity and / or noise level sensed by the sensing device.

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