Sound absorption structure, loudspeaker and electronic equipment

Abstract

The invention discloses a sound-absorbing structure, a loudspeaker and an electronic device, the sound-absorbing structure comprises a cavity and porous sound-absorbing particles, at least one side surface of the cavity is provided with micro-perforations, the porous sound-absorbing particles are arranged in the cavity, and the micro-perforations are arranged in the cavity. A preset interval is formed between the porous sound-absorbing particles and the inner wall corresponding to at least one side surface with the micro-perforations in the cavity; the porous sound-absorbing particles are surrounded by the cavity, at least one side surface of the cavity is provided with the micro-perforations, and the preset interval is formed between the porous sound-absorbing material and the inner wall corresponding to the at least one side surface with the micro-perforations in the cavity, so that on one hand, the porous sound-absorbing particles can be effectively fixed; on the other hand, the effect of further reducing F0 can be achieved through the specific structural design, and therefore the acoustic application range of the sound absorption structure can be expanded, and the acoustic performance of the sound absorption structure can be improved.

Description

Technical Field

[0001] The present invention relates to the field of sound absorbing materials, and in particular to a sound absorbing structure, a loudspeaker and an electronic device. Background Art

[0002] Commercial zeolite sound-absorbing materials are usually prepared into particles with a particle size of 150um-500um, which are completely filled in the thumb-sized back cavity of mobile phone speakers to improve the sound quality of mobile phones. However, compared with mobile phone speakers, audio equipment usually has a larger cavity, which requires a larger amount of particles. As the amount of particles increases, it is difficult to effectively fix the position of the particles in the back cavity. At the same time, more powerful speakers will cause the unfixed particles to collide violently and break into powder.

[0003] At present, the mainstream speaker cavity is filled with some sound-absorbing materials, the main purpose of which is to eliminate standing waves, and the effect on improving sound quality is limited. These sound-absorbing materials are mainly sound-absorbing foam materials. Although zeolite materials are better than sound-absorbing foam, they are rarely used in the field of audio, mainly because zeolite materials usually exist in the form of powder particles and are difficult to use directly. At present, zeolite sound-absorbing materials are only used in the field of mobile phone speakers, which greatly limits the large-scale use of this material. How to apply zeolite particles more widely in the field of acoustics has become a technical problem that needs to be solved in this field. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a sound absorbing structure, a loudspeaker and an electronic device, which can expand the application field of the sound absorbing structure and improve its applicability.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0006] A sound absorbing structure comprises a cavity and porous sound absorbing particles;

[0007] At least one side of the cavity has micro-perforations;

[0008] The porous sound-absorbing particles are arranged in the cavity;

[0009] There is a preset interval between the porous sound-absorbing particles and an inner wall corresponding to at least one side surface of the cavity having micro-perforations.

[0010] Further, the cavity is surrounded by a thin micro-perforated plate and a thin three-dimensional shell with an opening on one side;

[0011] The micro-perforations are arranged on the thin micro-perforated plate.

[0012] Furthermore, the micro-perforations on the thin micro-perforated plate are through holes with a sub-millimeter size.

[0013] Furthermore, the diameter of the through hole is 0.2 mm±0.05 mm.

[0014] Furthermore, the perforation rate of the through holes is 7%-12%.

[0015] Furthermore, the thickness of the thin micro-perforated plate is 0.1 mm-0.5 mm.

[0016] Furthermore, the thin micro-perforated board is one of a hard fiberboard, a plywood, a ceramic board, a gypsum board, an acrylic board and a polytetrafluoroethylene board.

[0017] Further, the thin micro-perforated plate is a ceramic plate;

[0018] The micro-perforations on the ceramic plate are formed by molding.

[0019] Further, the thin micro-perforated plate is an acrylic plate;

[0020] The micro-perforations on the acrylic plate are formed by machining with a CNC machine tool.

[0021] Furthermore, the thin three-dimensional shell is injection molded.

[0022] Further, the thin three-dimensional shell includes a bottom surface and a side surface;

[0023] A thin cavity is formed by the bottom surface and the side surfaces.

[0024] Furthermore, the wall thickness of the thin three-dimensional shell is 0.1 mm-1 mm.

[0025] Furthermore, the porous sound-absorbing particles include zeolite particles.

[0026] Furthermore, the zeolite particles are composed of zeolite particles with MFI pore structure and a high molecular polymer binder.

[0027] Furthermore, the zeolite particles include one or more of ZSM-5 and TS-1.

[0028] Furthermore, the particle size of the porous sound-absorbing particles ranges from 300um to 500um.

[0029] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0030] A loudspeaker comprises the above-mentioned sound absorbing structure, wherein the sound absorbing structure is arranged in the back cavity of the loudspeaker.

[0031] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0032] An electronic device comprises the above-mentioned speaker.

[0033] Furthermore, the electronic device includes a smart phone, a smart watch, a tablet computer, smart glasses, VR glasses, AR glasses, a smart TV, a smart speaker or a thin and light laptop.

[0034] The beneficial effects of the present invention are as follows: a cavity and porous sound-absorbing particles are arranged in the sound-absorbing structure, at least one side of the cavity has micro-perforations, the porous sound-absorbing particles are arranged in the cavity, and a preset interval is provided between the porous sound-absorbing particles and an inner wall corresponding to at least one side of the cavity having micro-perforations; the porous sound-absorbing particles are surrounded by the cavity, and at least one side of the cavity is provided with micro-perforations, and a preset interval is provided between the porous sound-absorbing material and an inner wall corresponding to at least one side of the cavity having micro-perforations. On the one hand, the porous sound-absorbing particles can be effectively fixed, and can be applied to both micro-speakers and various relatively large sound box devices, greatly expanding its acoustic application range. On the other hand, after the above-mentioned specific structure is set, the sound waves entering the sound-absorbing structure will first pass through the tuning of the micro-perforated plate and the air layer behind the micro-perforated side, and then interact with the porous sound-absorbing particles, and repeatedly reflect and resonate between the porous sound-absorbing particles, the air layer behind the micro-perforated side, and the micro-perforated side, which further reduces the F0 effect. In addition, the micro-perforated side, the air layer behind the micro-perforated side, and the porous sound-absorbing particle materials have different acoustic impedances. The sound waves entering the sound-absorbing structure will undergo multi-level acoustic impedance medium tuning, and the sound energy will be greatly dissipated. By adjusting the micro-perforated plate, cavity, and porous sound-absorbing particle structure, the acoustic performance of the above-mentioned sound-absorbing structure can be flexibly changed, further expanding its acoustic applicability. Therefore, through the above-mentioned specific sound-absorbing structure setting, not only can its acoustic applicability be expanded, but also its acoustic performance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure expansion of a sound absorbing structure according to an embodiment of the present invention;

[0036] Figure 2 is a perspective view of a sound absorbing structure according to an embodiment of the present invention;

[0037] Figure 3 A top view of a sound absorbing structure according to an embodiment of the present invention;

[0038] Figure 4 A front view of a sound absorbing structure according to an embodiment of the present invention;

[0039] Figure 5 This is a schematic diagram of the structure of a cavity in a sound absorbing structure according to an embodiment of the present invention;

[0040] Figure 6Another schematic diagram of the structure of a cavity in a sound absorbing structure according to an embodiment of the present invention;

[0041] Figure 7 Another schematic diagram of the structure of a cavity in a sound absorbing structure according to an embodiment of the present invention;

[0042] Description of labels:

[0043] 101. micro-perforation; 102. cavity; 103. porous sound-absorbing particles; 104. thin micro-perforated plate. DETAILED DESCRIPTION

[0044] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0045] The above-mentioned sound-absorbing structure of the present application can be applied to speakers in various application scenarios, including both micro speakers and relatively large speaker devices, such as smart phones, smart watches, tablet computers, smart glasses, VR glasses, AR glasses, smart TVs, smart speakers or thin and light laptops, etc., which are described below through specific implementation methods:

[0046] In an optional embodiment, if Figures 1 to 4 As shown, a sound absorbing structure includes a cavity 102 and porous sound absorbing particles 103;

[0047] At least one side of the cavity has micro-perforations 101;

[0048] The porous sound-absorbing particles 103 are disposed in the cavity 102;

[0049] There is a preset interval between the porous sound-absorbing particles and an inner wall corresponding to at least one side surface of the cavity having micro-perforations.

[0050] In an optional embodiment, different sides or front sides of the cavity may be provided with micro-perforations 101:

[0051] like Figure 5 As shown, the front and four sides of the cavity are provided with micro-perforations 101;

[0052] like Figure 6 As shown, the four sides of the cavity are all provided with micro-perforations 101;

[0053] like Figure 7 As shown, one side of the cavity has micro-perforations 101 .

[0054] In another optional embodiment, the cavity is surrounded by a thin micro-perforated plate 104 and a thin three-dimensional shell with an opening on one side;

[0055] The micro-perforations are arranged on the thin micro-perforated plate;

[0056] The micro-perforations on the thin micro-perforated plate are through holes with a sub-millimeter scale;

[0057] Wherein, the thin three-dimensional shell includes a bottom surface and a side surface;

[0058] A thin cavity is formed by the bottom surface and the side surfaces;

[0059] That is to say, in this embodiment, the sound-absorbing structure includes a thin micro-perforated plate, a thin three-dimensional shell, porous sound-absorbing particles, and a cavity surrounded by the micro-perforated plate and the bottom and side surfaces of the three-dimensional shell. Submillimeter through holes are opened on the micro-perforated plate, and the porous sound-absorbing particles are filled in the cavity.

[0060] In another optional embodiment, the aperture of the through hole is 0.2mm±0.05mm; the perforation rate of the through hole is 7%-12%. In a specific implementation, the perforation rate can be set to 10%; the thickness of the thin micro-perforated plate is 0.1mm-0.5mm.

[0061] In another optional embodiment, the thin micro-perforated board is one of a hard fiberboard, a plywood, a ceramic board, a gypsum board, an acrylic board and a polytetrafluoroethylene board.

[0062] In a specific implementation, the thin micro-perforated plate is a ceramic plate; the micro-perforations on the ceramic plate are formed by molding.

[0063] In another specific implementation, the thin micro-perforated plate is an acrylic plate; the micro-perforations on the acrylic plate are formed by CNC machine tools.

[0064] In another optional embodiment, the thin three-dimensional shell is a flat container with an open one side. The container is injection molded and has a wall thickness of 0.1mm-1mm. If the wall thickness is too thin, it is easy to be damaged. If the wall thickness is too thick, the volume occupied is too large, which is not conducive to the thinness of the product. The side of the container is perpendicular to the bottom surface and the opening surface, and the size of the opening surface is consistent with the size of the above-mentioned thin micro-perforated plate surface, that is, the thin micro-perforated plate surface just covers the opening of the container, wherein the shape of the thin micro-perforated plate can be square, round or other irregular shapes.

[0065] In another optional embodiment, the porous sound absorbing particles include zeolite particles;

[0066] The zeolite particles are composed of zeolite particles with MFI pore structure and high molecular polymer binder.

[0067] Specifically, the zeolite particles include one or more of ZSM-5 and TS-1.

[0068] The particle size of the porous sound-absorbing particles ranges from 300um to 500um, wherein the size of the micro-perforations is much smaller than the particle size of the porous sound-absorbing particles, which also ensures that the porous sound-absorbing particles will not leak out from the micro-perforations.

[0069] In another optional embodiment, a speaker comprises a sound absorbing structure as described in any one of the above embodiments, wherein the sound absorbing structure is arranged in the rear cavity of the speaker, and by arranging the above sound absorbing structure, the resonance volume of the speaker is further increased, and the resonance frequency F0 of the speaker is shifted more toward low frequency;

[0070] The size of the sound absorbing structure can be set according to actual needs. In the present embodiment, the sound absorbing structure is a rectangular parallelepiped with a total length of 5mm-30mm, a total width of 1mm-20mm, and a total height of 1mm-5mm.

[0071] In another optional implementation, an electronic device includes the speaker of the above implementation.

[0072] Among them, the electronic devices include smart phones, smart watches, tablet computers, smart glasses, VR glasses, AR glasses, smart TVs, smart speakers or thin and light laptops, etc.

[0073] The above-mentioned sound absorbing structure of the present application is tested by using specific examples and comparative examples as follows:

[0074] This test uses the micro-speaker module and the standard shell to form a certain rear acoustic cavity volume as the F0 test fixture. The rear acoustic cavity standard shell is made of acrylic material, and the internal space size is 18mm*12mm*5mm. When no material is placed in the rear acoustic cavity of the test fixture, the initial resonant frequency F0 value of the micro-speaker system is tested and recorded, and then the above-mentioned sound-absorbing structure or comparison material is placed in the rear acoustic cavity of the test fixture, and the F0' at this time is measured and recorded. △F0 of each embodiment or comparative example = F0-F0'.

[0075] Embodiment 1:

[0076] Figure 2This is a schematic diagram of a thin composite sound-absorbing structure composed of an acrylic micro-perforated plate, in which the acrylic plate is 0.3mm thick, the micro-perforation aperture is 0.2mm, the micro-perforation is machined by CNC, and the designed perforation rate is 10%. The outer dimensions of the injection molded shell cavity are 18mm*12mm*4.0mm (so that it can be placed just in the test fixture), the three-dimensional shell thickness is 0.2mm, and the cavity is filled with 0.3mL zeolite sound-absorbing particles (the packing density of zeolite particles is about 0.4g / mL, and the weight is about 120mg), and the particle size of the zeolite sound-absorbing particles is about 400 microns. The acrylic micro-perforated plate is fixed to the opening surface of the shell by UV glue.

[0077] The specific configurations of other embodiments and comparative examples are shown in Table 1:

[0078] Table 1 Comparison of measurement results of examples and comparative examples

[0079]

[0080]

[0081] A) Discussion on the benefits of thin structures

[0082] Comparison of the data of Example 1 with Comparative Examples 1 and 2 shows that: whether pure zeolite particles are placed in the rear sound cavity of the test tooling, or the thin composite structure designed by the present application without zeolite particles, the F0 of the system can be reduced (i.e., △F0>0); the embodiment combines the forms of Comparative Examples 1 and 2 to obtain the effect of 1+1>2, i.e., △F0 (Example 1)>△F0 (Comparative Example 1)+△F0 (Comparative Example 2). At present, the prior art generally directly uses the solution of Comparative Example 2 to reduce the F0 of the micro-speaker system, that is, directly filling the zeolite particle material in the rear cavity of the speaker. Example 1 obtains a better effect because the sound waves entering the rear cavity of the speaker will first pass through the tuning of the micro-perforated plate and the air layer behind the micro-perforated plate, and then act on the zeolite particle material, and repeatedly reflect and resonate between the zeolite particles, the air layer behind the micro-perforated plate, and the micro-perforated plate, which further reduces the F0. Furthermore, compared with Comparative Example 2, the microperforated plate, the air layer behind the microperforated plate, and the zeolite particle material in Example 1 have different acoustic impedances, and the sound waves entering the rear cavity of the speaker will undergo multi-level acoustic impedance medium tuning, and the sound energy will be greatly dissipated. The acoustic performance of the thin composite sound-absorbing structure can be changed by adjusting the microperforated plate, the cavity, the zeolite particle structure, etc.

[0083] B) Discussion on Micro-perforated Plate Materials

[0084] Comparison between Example 1 and Example 2 shows that a variety of materials can be made into the desired structure and achieve similar effects. Compared with acrylic, ceramic material has a rough surface, rich in micropores, and a higher density, which should be the reason why the thin composite sound-absorbing structure made of it has a higher △F0. However, considering the manufacturing cost and the ability to resist impact deformation (not easy to break when falling), acrylic material has more advantages.

[0085] C) Discussion on the thickness of micro-perforated plate

[0086] By comparing Example 1 with Examples 3 and 4, it can be seen that increasing the thickness of the micro-perforated plate will increase the △F0 of the thin composite sound-absorbing structure, which is beneficial. However, considering the size limit of the micro-speaker, the size of the thin composite sound-absorbing structure should be as thin as possible, and a certain thickness of the cavity should be ensured. Taking the embodiment of the present application as an example, the inner cavity thickness of the test tooling is only 5mm, and when the plate thickness is 0.5mm, the cavity thickness of the thin composite sound-absorbing structure is 4mm, totaling 4.5mm; further increasing the thickness of the micro-perforated plate requires reducing the cavity thickness of the thin composite sound-absorbing structure, which can be seen in the following discussion. This is not worth the loss. Therefore, in this embodiment, the plate thickness needs to be limited to no more than 0.5mm. Of course, if the thickness of the rear sound cavity is allowed when designing the micro-speaker system, the thickness of the micro-perforated plate can be increased accordingly. When it is too thin, the mechanical properties of the micro-perforated plate will deteriorate. This is manifested in the fact that ceramic plates are easy to break, acrylic plates are easy to warp, etc.

[0087] D) Discussion on the aperture of micro-perforated plate

[0088] Comparison between Example 1 and Examples 5 and 6 shows that increasing the aperture of the micro-perforated plate is beneficial to improving the ΔF0 of the thin composite sound-absorbing structure. When the aperture is 0.15 mm, the difference in ΔF0 between Example 5 and Comparative Example 2 is not large, and basically no benefit can be obtained through the thin composite sound-absorbing structure. When the aperture is increased to more than 0.25 mm, it is close to the size of the zeolite particles (ranging from 300 to 500 microns), which easily causes the zeolite particles to get stuck in the aperture or even fall out.

[0089] E) Discussion on the shell thickness of thin three-dimensional shells

[0090] Comparison between Example 1 and Examples 7 and 8 shows that it mainly affects the effective volume of the cavity of the thin composite sound-absorbing structure. It is necessary to consider that a shell that is too thin is not strong enough, and a shell that is too thick will increase the production cost and will cause more dead volume in the acoustic back cavity, reducing the ΔF0 effect of the thin composite sound-absorbing structure.

[0091] F) Discussion on Zeolite Particle Size

[0092] Comparison between Example 1 and Examples 9 and 10 shows that there is little difference. The size of the zeolite particles is not strictly limited when used, and only needs to be much larger than the aperture of the micro-perforated plate.

[0093] G) Cavity thickness of thin composite sound-absorbing structure

[0094] By comparing Example 1 with Examples 11 and 12, it can be seen that the thicker the cavity thickness of the thin composite sound-absorbing structure, the better its △F0 effect. The reason is that the thicker the cavity thickness of the thin composite sound-absorbing structure, the thicker the air layer thickness behind the micro-perforated plate is, and the stronger the acoustic resonance dissipation capacity is when the zeolite particle filling volume is constant. The range of 2 to 4 mm is set in the implementation method because the inner cavity thickness of the test tooling in the embodiment of the present application is only 5 mm, and the cavity thickness of the thin composite sound-absorbing structure is at most 4.7 mm when the plate thickness is 0.3 mm. Since 0.3 mL of zeolite particles are filled, the cavity thickness cannot be less than 1.8 mm. By further comparing Example 12 with Comparative Example 2, when the cavity thickness is reduced to 2 mm, the thin composite sound-absorbing structure is no longer better than the acoustic effect of pure zeolite particles, and may even be degraded, which is not worth the loss. Therefore, in the present application, the cavity thickness is limited to not less than 2 mm. Of course, if the thickness of the rear sound cavity is allowed when the micro-speaker system is designed, the cavity thickness of the thin composite sound-absorbing structure can be increased accordingly.

[0095] In summary, the present invention provides a sound-absorbing structure, a loudspeaker and an electronic device, wherein a cavity and zeolite sound-absorbing particles are arranged in the sound-absorbing structure, at least one side of the cavity has micro-perforations, porous sound-absorbing particles are arranged in the cavity, and a preset interval is provided between the porous sound-absorbing particles and the inner wall corresponding to at least one side of the cavity having micro-perforations, and the cavity is surrounded by a thin micro-perforated plate and a thin three-dimensional shell with an opening on one side. By reasonably setting the thickness of the thin micro-perforated plate and the thin three-dimensional shell and the size of the cavity, on the one hand, the zeolite sound-absorbing particles can be effectively fixed, and on the other hand, the sound waves entering the sound-absorbing structure will first Through the tuning of the micro-perforated plate and the air layer behind the micro-perforated side, and then interacting with the zeolite sound-absorbing particles, and repeatedly reflecting and resonating between the zeolite sound-absorbing particles, the air layer behind the micro-perforated side, and the micro-perforated side, the effect of further reducing F0 is achieved. In addition, the micro-perforated side, the air layer behind the micro-perforated side, and the zeolite sound-absorbing particle materials have different acoustic impedances. The sound waves entering the sound-absorbing structure will undergo multi-level acoustic impedance medium tuning, and the sound energy will be greatly dissipated. By adjusting the micro-perforated plate, the cavity, and the zeolite sound-absorbing particle structure, the acoustic performance of the above-mentioned sound-absorbing structure can be flexibly changed, further expanding its acoustic applicability. Therefore, through the above-mentioned specific sound-absorbing structure setting, not only can its acoustic applicability be expanded, but also its acoustic performance can be improved.

[0096] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A sound absorbing structure, characterized in that: including cavities and porous sound absorbing particles; At least one side of the cavity has micro-perforations; The porous sound-absorbing particles are arranged in the cavity; There is a preset interval between the porous sound-absorbing particles and an inner wall corresponding to at least one side surface of the cavity having micro-perforations.

2. A sound absorbing structure according to claim 1, characterized in that: The cavity is surrounded by a thin micro-perforated plate and a thin three-dimensional shell with an opening on one side; The micro-perforations are arranged on the thin micro-perforated plate.

3. A sound absorbing structure according to claim 2, characterized in that: The micro-perforations on the thin micro-perforated plate are through holes with a sub-millimeter scale.

4. A sound absorbing structure according to claim 3, characterized in that: The aperture of the through hole is 0.2 mm±0.05 mm.

5. A sound absorbing structure according to claim 3, characterized in that: The perforation rate of the through holes is 7%-12%.

6. A sound absorbing structure according to claim 2, characterized in that: The thickness of the thin micro-perforated plate is 0.1 mm-0.5 mm.

7. A sound absorbing structure according to claim 2, characterized in that: The thin micro-perforated board is one of a hard fiberboard, a plywood, a ceramic board, a gypsum board, an acrylic board and a polytetrafluoroethylene board.

8. A sound absorbing structure according to claim 7, characterized in that: The thin micro-perforated plate is a ceramic plate; The micro-perforations on the ceramic plate are formed by molding.

9. A sound absorbing structure according to claim 7, characterized in that: The thin micro-perforated plate is an acrylic plate; The micro-perforations on the acrylic plate are formed by machining with a CNC machine tool.

10. A sound absorbing structure according to claim 2, characterized in that: The thin three-dimensional shell is injection molded.

11. A sound absorbing structure according to claim 10, characterized in that: The thin three-dimensional shell includes a bottom surface and a side surface; A thin cavity is formed by the bottom surface and the side surfaces.

12. A sound absorbing structure according to claim 10 or 11, characterized in that: The wall thickness of the thin three-dimensional shell is 0.1 mm-1 mm.

13. A sound absorbing structure according to any one of claims 1 to 11, characterized in that: The porous sound absorbing particles include zeolite particles.

14. A sound absorbing structure according to claim 13, characterized in that: The zeolite particles are composed of zeolite particles with MFI pore structure and high molecular polymer binder.

15. A sound absorbing structure according to claim 14, characterized in that: The zeolite particles include one or more of ZSM-5 and TS-1.

16. A sound absorbing structure according to any one of claims 1 to 11, characterized in that: The particle size of the porous sound-absorbing particles ranges from 300um to 500um.

17. A loudspeaker, characterized in that: The speaker comprises a sound absorbing structure as claimed in any one of claims 1 to 16; The sound absorbing structure is arranged in the rear cavity of the speaker.

18. An electronic device, characterized in that: The electronic device comprises a speaker as claimed in claim 17.

19. An electronic device according to claim 18, characterized in that: The electronic device includes a smart phone, a smart watch, a tablet computer, smart glasses, VR glasses, AR glasses, a smart TV, a smart speaker or a thin and light laptop.

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