CN116847254A - Sound absorbing material, sound generating device and electronic equipment - Google Patents
Sound absorbing material, sound generating device and electronic equipment Download PDFInfo
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- CN116847254A CN116847254A CN202310798767.2A CN202310798767A CN116847254A CN 116847254 A CN116847254 A CN 116847254A CN 202310798767 A CN202310798767 A CN 202310798767A CN 116847254 A CN116847254 A CN 116847254A
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/06—Loudspeakers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/02—Details
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2400/00—Loudspeakers
- H04R2400/11—Aspects regarding the frame of loudspeaker transducers
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
The invention discloses a sound absorbing material, a sound generating device and electronic equipment. The sound absorbing material comprises: the carbon nano tube powder comprises a plurality of layers of coaxially arranged tubular structures, the number of layers of the tubular structures ranges from 2 to 100, the tube wall of each layer of the tubular structure comprises a plurality of hexagonal rings formed by six carbon atoms, defect holes formed by surrounding more than six carbon atoms are formed in the tube wall of the tubular structure, and the average pore diameter of the defect holes ranges from 0.5nm to 10nm; wherein the hexagonal ring forms micropores for ventilation, and the defective holes and gaps among the multiple layers of tubular structures form micropores and/or mesopores for ventilation; and the adhesive is used for bonding the plurality of carbon nano tube powder bodies to form the sound absorbing material. The sound absorbing material provided by the invention can improve the resonance frequency of an acoustic device.
Description
Technical Field
The invention relates to the technical field of acoustics, in particular to a sound absorbing material, a sound generating device and electronic equipment.
Background
In recent years, in the trend of increasingly lighter and thinner electronic products, the space reserved for acoustic devices such as speakers in products such as mobile phones and tablet computers is smaller and smaller. In order to meet the design requirements of electronic products, speakers are also gradually miniaturized, and the mass and volume of speakers are gradually reduced. This design results in a substantial reduction in the volume of the acoustic back volume of the speaker, affecting the sound performance of the speaker. Those skilled in the art have attempted to improve the acoustic performance of a loudspeaker by using porous materials to achieve a virtual increase in the resonant space of the acoustic back volume of the loudspeaker.
On the other hand, the solution of using porous materials in the speaker also faces weight problems, and the overall weight of the speaker increases due to the addition of porous materials. This may cause an increase in the overall weight of the electronic product in which the speaker is mounted, which may have a negative effect on the use experience. In this regard, there is a need to improve the weight problem as well, in the case of satisfying acoustic performance.
Disclosure of Invention
To solve at least one technical problem in the above description, an object of the present invention is to provide a sound absorbing material having good sound absorbing performance relative to existing porous materials.
The sound absorbing material comprises:
the carbon nano tube powder comprises a plurality of layers of coaxially arranged tubular structures, the number of layers of the tubular structures ranges from 2 to 100, the tube wall of each layer of the tubular structure comprises a plurality of hexagonal rings formed by six carbon atoms, defect holes formed by surrounding more than six carbon atoms are formed in the tube wall of the tubular structure, and the average pore diameter of the defect holes ranges from 0.5nm to 10nm; wherein the hexagonal ring forms micropores for ventilation, and the defective holes and gaps among the multiple layers of tubular structures form micropores and/or mesopores for ventilation;
and the adhesive is used for bonding the plurality of carbon nano tube powder bodies to form the sound absorbing material.
Optionally, at least the hexagonal ring is spaced between two of the defective holes.
Optionally, the defect hole is formed on the wall of the tubular structure through an opening process;
the perforating process comprises the following steps:
at least one of an electron beam irradiation process, a lithography process, or a gas plasma etching process.
Optionally, in the multilayer tubular structure, at least a portion of the defect holes on the tubular structure of adjacent layers communicate along a radial direction of the tubular structure.
Optionally, in the multilayer tubular structure, at least a portion of the defective cells on the three layers of the tubular structure are in integral communication.
Optionally, in the multilayer tubular structure, a depth of communication of the plurality of defect holes communicated in a radial direction of the tubular structure in the radial direction of the tubular structure is greater than or equal to 0.5nm.
Optionally, in the multilayer tubular structure, a spacing between two adjacent layers of the tubular structure is greater than or equal to 0.3nm;
and/or the distance between two adjacent layers of the tubular structures is less than or equal to 1.5nm.
Optionally, the mass ratio of carbon element in the carbon nanotube powder is greater than or equal to 90%;
and/or the mass ratio of oxygen element in the carbon nano tube powder is less than or equal to 5%.
Optionally, the aspect ratio of the tubular structure of the carbon nanotube powder ranges from 500 to 50000.
Optionally, the tap density of the carbon nano tube powder is in the range of 0.05g/cm 3 -0.1g/cm 3 。
Optionally, the specific surface area of the carbon nanotube powder is in the range of 200m 2 /g-2500m 2 /g。
Optionally, the sound absorbing material is in a particle shape, and the particle size of the sound absorbing material ranges from 100 micrometers to 1000 micrometers;
alternatively, the sound absorbing material may be in the form of a block.
Alternatively, the number of layers of the tubular structure may range from 2 to 20 layers.
The invention also provides a sound generating device provided with the sound absorbing material, which comprises:
sound producing unit, shell and said sound absorbing material;
the sound generating unit is arranged in the shell and is matched with the shell to define a front sound cavity and a rear sound cavity, and the sound absorbing material is filled in the rear sound cavity and/or the front sound cavity.
The invention also provides electronic equipment with the sounding device.
According to the invention, the sound absorbing material is prepared from the carbon nanotube powder, and the adsorption and desorption effects on air molecules are realized by utilizing the pore canal structure and the multilayer structure in the carbon nanotubes, so that the acoustic treatment effect of the sound absorbing material is achieved. The carbon nano tube powder and the adhesive are combined to form the sound absorbing material, the density of the sound absorbing material is smaller than that of the existing material, and the light weight improvement is realized.
Other features of the present invention and its advantages will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
Fig. 1 is a schematic structural diagram of a sound absorbing material and carbon nanotube powder therein according to the present invention;
FIG. 2 is a schematic diagram of a side microstructure of a carbon nanotube powder according to the present invention;
FIG. 3 is a schematic diagram of an end portion axial side structure of the carbon nanotube powder according to the present invention;
FIG. 4 is a schematic view of a radial cross-sectional structure of a carbon nanotube powder according to the present invention;
FIG. 5 is a graph of IMP test of the sound absorbing material provided by the present invention versus the prior art comparative scheme;
fig. 6 is a schematic cross-sectional view of a sound generating apparatus according to the present invention.
Reference numerals illustrate:
1. a sound absorbing material; 10. a housing; 11. carbon nanotube powder; 12. a hexagonal ring; 13. defect holes; 14. a tubular structure; 101. a rear acoustic cavity; 102. a front acoustic cavity; 20. sounding device
Detailed Description
Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
The invention provides a sound absorbing material 1, wherein the sound absorbing material 1 comprises carbon nano tube powder 11 and an adhesive. After a large amount of carbon nanotube powder 11 is mixed and bonded by an adhesive, the shaped sound absorbing material 1 can be formed. In the embodiment shown in fig. 1, the sound absorbing material 1 contains a large amount of carbon nanotube powder 11.
The carbon nanotube powder 11 employed in the present invention includes a tubular structure 14 in a multi-layered arrangement. Each layer of the tubular structure 14 is a layer of the tubular structure 14 of the carbon nanotube powder 11. As shown in fig. 2, which illustrates the arrangement of carbon atoms on the single-layer tubular structure 14. The tubular structure 14 is formed from an arrangement of carbon atoms. In a typical configuration, six carbon atoms are connected around to form a hexagonal ring 12, and a plurality of hexagonal rings 12 are arranged to form the wall of the tubular structure 14, thereby enclosing the tubular structure 14.
The invention firstly utilizes the basic characteristics of the carbon nano tube powder 11 to realize the adsorption and desorption of air molecules. The pore size of the hexagonal ring 12 formed by winding six carbon atom rings floats up and down at 0.28nm, which can allow air molecules to pass through to a certain extent, and when air circulates, the air molecules can pass through the hexagonal ring 12 on the tubular structure 14 and enter the inside of the tubular structure 14 or flow out of the inside of the tubular structure 14, and the tubular structure 14 plays a role in absorbing and releasing air.
Further, as described above, the carbon nanotube powder 11 employed in the present embodiment includes the multilayer tubular structure 14. The tubular structure 14 is in a multi-layered, nested form, constituting a multi-layered, coaxially disposed configuration, as shown in fig. 3. Fig. 3 schematically illustrates three layers of tubular structures 14 nested together, with the cylindrical barrels representing the carbon tubular structures 14 formed by the hexagonal ring 12 arrangement. Alternatively, the carbon nanotube powder 11 has a tubular structure 14 with 2 to 100 layers. A gap exists before the adjacent two-layer tubular structures 14, and the size of the gap (interlayer spacing) floats up and down at 0.35nm due to the growth characteristics of the multi-layer carbon nanotube powder 11 structure. The size of the layer gap is slightly larger than the size of the hexagonal ring 12, which together with the hexagonal ring 12 can provide space for the circulation and storage of air molecules. The large number of gaps between the hexagonal rings 12 and the tubular structures 14 provide micropores for the carbon nanotube powder 11 to absorb and release air, and can play roles in absorbing sound and adjusting the resonant frequency of the loudspeaker in practical application.
In particular, the carbon nanotube powder 11, that is, the tubular structure 14, used in the present invention has defective holes 13. The defective cells 13 may be formed in the tubular structure 14 by a machining process. The defect holes 13 have an average pore diameter ranging from 0.5nm to 10 nm. The defective cells 13 refer to relatively large hole structures as shown in fig. 2 and 3. On the tubular structure 14, part of the carbon atoms do not form around the hexagonal ring 12 due to the effect of the post-processing process, but rather form around a ring of more than six carbon atoms, the corresponding hole size of which is increased with respect to the hexagonal ring 12. The number of carbon atoms forming the defective holes 13 is variable, and the range of the diameters of the defective holes 13 is large, so that the defective holes 13 with relatively small sizes can be used as micropores for storing and absorbing air molecules, and the defective holes 13 with relatively large sizes can be used as a circulation channel for the air molecules from the inside to the outside of the multilayer tubular structure 14, so that the defective holes 13 can be used as mesopores to be combined with a pore structure as micropores, and the sound absorbing material 1 has good sound absorbing effect. When the sound vibration is transmitted to the sound absorbing material 1, air molecules can quickly enter the micropores through the mesopores or quickly flow out of the micropores through the mesopores to the outside of the sound absorbing material 1. The defect hole 13 shown in fig. 3 is a defect hole 13 formed by the standard absence of carbon atoms, and in practical application, the defect hole 13 may be formed by deforming the position of carbon atoms, and the like, and is not limited to the defect hole 13 having a regular shape shown in fig. 3.
The invention utilizes the self structural characteristics of the carbon nano tube powder 11, combines the characteristics of large specific surface area and a large number of holes of the tubular structure 14 of the multi-layer carbon nano tube powder 11, and realizes the application of the carbon nano tube powder in the acoustic field. Furthermore, in order to enable the carbon nano tube powder 11 to exert acoustic performance superior to that of the existing porous material in acoustic aspect, defective holes 13 are formed in a tubular structure 14 of the carbon nano tube powder 11, and the defective holes 13 are utilized to improve the response capability to the flow of air, so that the requirements of rapid absorption and release of air required by an acoustic device are met.
Specifically, the size of oxygen molecules in air molecules is about 0.32nm, the size of nitrogen molecules is about 0.24nm, the size of water molecules is about 0.18nm, and the size of carbon dioxide molecules is about 0.44nm. Six carbon atoms surrounding hexagonal ring 12 at least allows nitrogen molecules to flow through. In the case of defective cells 13, one or two carbon atoms may be missing from the hexagonal ring 12, which allows two adjacent hexagonal rings 12 to merge into one defective cell 13 of larger size, the smallest size of the defective cell 13 being close to 0.5nm. In this way, all air molecules can pass through the smallest defect hole 13, providing good circulation space for air molecules.
In the technical scheme of the invention, the average pore diameter of the defect pores 13 is in the range of 0.5nm to 10nm. According to the acoustic performance requirements, the defective holes 13 can be controlled in a concentrated manner to a pore diameter of about 0.5nm by a processing process, and a large number of defective holes 13 having a large size and an average size of approximately 5nm can be generated.
Alternatively, the average pore diameter of the defective pores 13 may be 0.5nm, 0.6nm, 1nm, 1.5nm, 2nm, 3nm, 4nm, 5nm, 10nm.
In the embodiment where the average pore diameter of the defective pores 13 is 0.5nm, a large number of defective pores 13 are relatively small in size, store air molecules, provide air molecules with a strong ability to absorb space, and have a relatively small number of defective pores 13 of a large size. The sound absorbing material 1 is suitable for specific sound equipment requirements, has strong air molecule absorption capacity, and can greatly improve the sound vibration elimination and buffering effect of specific areas.
In the embodiment in which the average pore diameter of the defective pores 13 is 0.6nm, the number of defective pores 13 having a size exceeding 0.6nm is increased, and the size of such defective pores 13 allows two or more air molecules to pass through at the same time, the adsorption-desorption sensitivity of the sound absorbing material 1 of this embodiment to air molecules is remarkably improved, and air can flow in the defective pores 13 more rapidly, relative to the embodiment in which the average pore diameter is 0.5 nm. The embodiment is suitable for being applied to electronic equipment such as headphones, mobile phone speakers and the like, and can be matched with the rapid air flow brought by the high-frequency vibration of the electronic product in the aspect of acoustics to rapidly absorb and release air molecules. In addition, the defective cells 13 in this embodiment can also provide absorption and storage functions for air molecules. The size of the defect hole 13 is relatively small as a whole, and there are a large number of small defect holes 13 so that air molecules are fixed therein.
In the embodiment in which the average pore diameter of the defective pores 13 is 4nm, the number of defective pores 13 having a large size is significantly increased, and a plurality of air molecules can pass through such defective pores 13 side by side at the same time. Such a sound absorbing material 1 can provide a sufficient duct structure for the rapid circulation of air. In certain acoustic device environments, such as vehicle audio equipment, a large amount of air is required to rapidly flow in the space, such as the acoustic rear cavity, to ensure overall acoustic performance. Defect holes 13 having a relatively large average size in this solution can meet such a demand.
In the technical scheme of the invention, the average pore diameter of the defect pores 13 is not easy to be larger than 10nm. The excessive average pore diameter of the defective pores 13 can cause unstable tubular structure 14 of the carbon nanotube powder 11, and the tubular structure 14 is easy to generate obvious deformation and collapse phenomena, so that the number of micropores in the carbon nanotube powder 11 is reduced, and the performance of absorbing air molecules is damaged. Thus, the average pore diameter of the defective pores 13 in this embodiment can be selected to be less than 10nm.
Optionally, at least one hexagonal ring 12 is spaced between each of the defect holes 13 on the wall of the tubular structure 14 of the carbon nanotube powder 11. The hexagonal ring 12 is a stable structure constituting the tubular structure 14, and other annular structures lacking a portion of the carbon atoms constitute a disadvantage in the overall framework stability of the tubular structure 14. Similarly, ring structures surrounded by more carbon atoms may also cause a decrease in the stability of the tubular structure 14, such as defective holes 13 formed by a predetermined machining process. In a preferred embodiment of the present invention, at least hexagonal rings 12 are spaced between two defective holes 13, and the number of the hexagonal rings 12 spaced may be plural, which is not limited in this aspect. Through the structural requirement and the control of the preset processing technology, at least one or more hexagonal rings 12 are arranged among each defective hole 13, the reliability of the integral structure of the tubular structure 14 of the carbon nano tube powder 11 is improved, and the existence of micropores and mesopores is ensured.
Alternatively, the process for forming defective hole 13 may include at least one of an electron beam irradiation treatment, a photolithography treatment, or a gas plasma etching. The above treatment can remove part of the carbon atoms from the original hexagonal ring 12, thereby forming the defect hole 13 having a larger size. Taking the electron beam irradiation treatment as an example, the irradiation power, irradiation time, irradiation interval, and irradiation diameter of the optical head of the electron beam may be controlled so as to perform a predetermined treatment on the tubular structure 14 of the carbon nanotube powder 11. By the process control, the defect holes 13 can be formed in a uniform distribution and a periodic distribution. The intensity of the process, e.g. the irradiation power of the electron beam, may control the size of the defect hole 13. Avoiding the defect hole 13 being too small to meet the requirement of improving the air circulation performance; collapse of the tubular structure 14 due to oversized defective cells 13 can also be avoided.
Alternatively, as shown in fig. 4, in the multilayer tubular structure 14, defective cells 13 provided in adjacent layers of the tubular structure 14 may be at least partially communicated with each other in the radial direction of the tubular structure 14. Fig. 4 schematically shows, in a radial section, the defective holes 13 in adjacent tubular structures 14 in the form of circles. The three defect holes 13 on the left side are not communicated in the radial direction (diameter direction), and the three defect holes 13 on the right side are partially communicated in the radial direction. For example, a defective hole 13 is formed in a specific position of the tubular structure 14 of the inner layer, and a defective hole 13 is also formed in a corresponding specific position of the tubular structure 14 of the adjacent outer layer. The defect holes 13 in the inner and outer layers are through-going in the radial direction of the tubular structure 14, as shown in the right defect hole 13 of fig. 3. The communication relationship may be that the two defective holes 13 are completely opposite, or that the two defective holes 13 are partially opposite with each other in a staggered manner. As long as the defect holes 13 formed along the radial direction overlap, air molecules can be made to enter and exit the carbon nanotube powder 11 along the radial direction of the tubular structure 14. Further, as described above, the tubular structure 14 is formed with a plurality of defect holes 13, and the multilayer tubular structure 14, which is nested in each other and arranged coaxially, is formed with the defect holes 13. Wherein it is not necessary that all defective cells 13 be in radial communication, so long as a portion of defective cells 13 are capable of radial communication with defective cells 13 in an adjacent inner or outer tubular structure 14. The defect hole 13 structure enables the multilayer tubular structure 14 to integrally form intricate mesoporous and microporous channels in the radial and axial interlayer gaps, which is beneficial to the air molecules entering from the outside to the inside of the tubular structure 14 and realizes the absorption of the sound absorbing material 1 to the air molecules.
Optionally, in a plurality of layers of said tubular structure 14, at least a portion of defective cells 13 in three layers of tubular structure 14 are in integral communicating relationship. That is, as shown in fig. 4, in the three-layer tubular structure 14 that are continuously adjacent, there is a structural feature that the defective holes 13 on the three-layer tubular structure 14 are continuously penetrated. More preferably, the defective holes 13 in the further tubular structure 14 may be connected through. The spacing between two adjacent tubular structures 14 is about 0.35nm, and the defect holes 13 of at least three layers are communicated, so that a long pore canal in the depth direction, which is the radial direction of the tubular structure 14, can be formed. The defective holes 13 in the further tubular structure 14 can be formed to have a deeper depth if they can be directly penetrated. This configuration facilitates a consistent, continuous flow of air molecules either inwardly of the tubular structure 14 or outwardly in opposite directions. The structural characteristics can improve the flow and response rate of air adsorption and desorption, and are favorable for realizing high-sensitivity vibration by matching with an acoustic device. In particular, the defect hole 13 penetrating through the tubular structure 14 may also integrally penetrate through the entire multilayer tubular structure 14, and the integrally penetrating multilayer defect hole 13 may greatly improve the mesoporous length and smoothness in the multilayer tubular structure 14, so that air molecules can be absorbed by the tubular structure 14 in a large amount and rapidly.
Alternatively, the spacing between the multilayer tubular structures 14 and the number of layers of communicating defective holes 13 may affect the depth of defective holes 13 that pass through in the depth direction of the tubular structures 14. The depth is preferably greater than 0.5nm so that air molecules do not clog back and forth while flowing over such radial channels. The radial duct constituted by the communicating defective cells 13 is able to accommodate the next at least one air molecule. For example, the communication depth of the plurality of defect holes 13 in the radial direction may be 0.5nm, 0.8nm, 1.2nm, 1.5nm, 2.0nm, 2.5nm, or the like. As described above, the radial cells formed by the communication of the defective cells 13 may be integrally penetrated through the entire multilayer tubular structure 14 in the radial direction. The formation of such through structures has a certain chance. Alternatively, the depth of communication of the multi-layer defect holes 13 along the radial direction of the tubular structure 14 is up to 3nm. The size can meet the requirement of rapid influx and influx of air molecules along the radial direction, and can fully utilize the micropore structures between layers and in the layers.
Alternatively, in the multilayer tubular structure 14, the spacing between adjacent two layers of the tubular structure 14, i.e., the layer spacing, is greater than or equal to 0.3nm. If the interlayer spacing is less than 0.3nm, the space between the two layer tubular structures 14 is insufficient to constitute a microporous structure into which air molecules are difficult to enter, and the sound absorbing performance of the carbon nanotube powder 11 is degraded. On the other hand, too small an interlayer spacing may collapse or deform the multilayer tubular structure 14, which may also seriously affect the sound absorbing performance of the carbon nanotube powder 11. The gaps between the multilayer tubular structures 14 may change due to deformation of the tubular structures 14, defective holes 13, and the like.
Alternatively, the spacing between adjacent two tubular structures 14 is less than or equal to 1.5nm. For example, the interlayer spacing may be 0.3nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 1.0nm, 1.2nm, 1.5nm. If the tubular structures 14 of adjacent layers are loose, deformed, etc., the structural stability is significantly reduced, and correspondingly, the layer spacing is too large, for example, more than 2nm. The multilayer tubular structure 14 adopted in the scheme needs to avoid selecting loose materials, and the structural characteristics of layer-by-layer compaction and wrapping are utilized to form enough micropores and mesopores. Preferably, the spacing between two adjacent layers of the tubular structures 14 is greater than or equal to 0.5nm and less than or equal to 1nm. Within this size range, the tubular structure 14 of the multiple layers has the best structural stability, and can form a sufficient number of micropores and mesopores, thereby improving the sound absorbing performance of the sound absorbing material 1. In particular, in the case where the interlayer spacing is within this range, the defective holes 13 can constitute radial cells in the range of 0.5nm to 2nm in the radial direction of the multilayer tubular structure 14. Even if a defective hole 13 is not communicated with other defective holes 13 along the radial direction, the space formed along the radial direction can also meet the basic space requirement of radial flow of air molecules, and a better communication effect is achieved.
Optionally, the mass ratio of the carbon element in the carbon nanotube powder 11 is greater than or equal to 90% to ensure the purity of the carbon nanotube powder 11. If the mass ratio of the impurity element is too high, the structural reliability of the tubular structure 14 is deteriorated, and structural defects such as breakage, deformation, collapse and the like are liable to occur. The increase of structural defects can seriously affect the micropore and mesopore contents of the carbon nanotube powder 11. According to the technical scheme, the defect holes 13 are used for improving the content of mesopores and micropores, and the defect holes 13 can bring structural defects to reduce structural stability. In this case, the mass of the carbon element is required to be relatively high, and it is required to reach 90% or more, for example, 92%, 93%, 94%, 95%, 96%, 97%, 98% by mass, so as to ensure that the hexagonal ring 12 on the tubular structure 14 of the carbon nanotube powder 11 is sufficiently structured to maintain a good structural morphology.
Optionally, the mass ratio of oxygen element in the carbon nanotube powder 11 is less than or equal to 5%. The oxygen element in the carbon nanotube powder 11 is generally present in the form of hydroxyl group and carboxyl group. This structure is prone to structural defects and instability. The more oxygen atoms represent more defects of the carbon nanotube powder 11, and the structure is unstable. In addition, the oxygen-containing groups have polarity, so that the adsorption of water vapor and other polar organic molecules by the material is easy to cause the blockage of micropores and mesopores, and the sound absorption performance is invalid. In practical applications, the sound absorbing material 1 inevitably contacts with water molecules and other organic molecules. The oxygen element groups formed in the sound absorbing material 1 are easily adsorbed and bonded to the above molecular structure, and thus the pores originally in the carbon nanotube powder 11 are blocked by the newly bonded molecules. In this regard, the present invention requires that the mass ratio of oxygen element be controlled to a specific ratio in order to ensure the overall stability and channel content of the tubular structure 14. For example, the mass ratio of oxygen element is preferably 4%, 3%, 2%, or 1%. Preferably, the mass ratio of the oxygen element is 3% or less.
Alternatively, the ratio of the length and the diameter of the tubular structure 14 in the carbon nanotube powder 11, that is, the aspect ratio, ranges from 500 to 50000. The length-diameter ratio of the tubular structure 14 is not easy to be too long, otherwise, the fibrous carbon nanotube powder 11 is easy to generate the defect of winding and agglomerating during the process of dispersing, pulping and bonding, and finally the dispersion of the carbon nanotube powder 11 in the supported sound absorbing material 1 is extremely uneven. On the other hand, the case of too large aspect ratio may cause insufficient number of layers of the multilayer tubular structure 14, the amount of pore fusion in the tubular structure 14 is relatively small, and it is impossible to form an intricate pore structure through the hexagonal ring 12, the defective pore 13, etc., and the sound absorbing performance is poor. Particularly, if the aspect ratio of the tubular structure 14 is large, the communicating defective holes 13 cannot sufficiently exert the air circulation function of the mesopores, and the defective holes 13 are distributed throughout the long tubular structure 14, so that the communicating function cannot be exerted. In this regard, the aspect ratio of the tubular structure 14 of the carbon nanotube powder 11 may be selected from 50000, 40000, 30000, 20000, 10000, 8000, 6000, 4000, 3000, 2500, 2000, 1500, 1200, 1100, 900, 700, 500. The sound absorbing material 1 has long fibers in an embodiment having a large aspect ratio of the tubular structure 14, for example, in an embodiment having aspect ratios of 50000 and 40000 30000, and the entire pore volume after the dispersion bonding molding is large, and is suitable for use as an acoustic device in a large space such as a car audio. For the tubular structure 14 with a moderate or smaller length-diameter ratio, for example, the embodiments with the length-diameter ratio of 2500, 1200 and 500, the tubular structure 14 is not easy to intertwine to cause the situation of pore stacking and non-uniformity. A more uniform distribution can be achieved during the dispersion bonding molding, which is suitable for preparing small-sized sound absorbing material 1 particles, and filling in micro-acoustic devices. Preferably, the aspect ratio of the tubular structure 14 of the carbon nanotube powder 11 is 4000 to 1000.
Optionally, the tap density of the carbon nanotube powder 11 is in the range of 0.05g/cm 3 -0.1g/cm 3 . The density of the carbon nanotube powder 11 is significantly reduced compared to the density of porous materials such as molecular sieves in the prior art. In the same volume, it can be reduced in weight significantly. In the case that the carbon element mass content of the carbon nanotube powder 11 is greater than or equal to 95%, the higher the purity of the carbon element of the material is, the lower the tap density is, and the carbon element of the material can reach 0.05g/cm 3 . In an embodiment of the invention wherein the carbon content is about 90% by mass, the tap density can also be up to 0.1g/cm 3 . The density of the carbon nanotube powder 11 is reduced as much as possible, so as to meet the light and thin design requirements of acoustic devices and electronic products.
The specific surface area of the carbon nanotube powder 11 is in the range of 200m 2 /g-2500m 2 And/g. The larger the specific surface area of the carbon nanotube powder 11, the pores inside the powderThe more abundant the channel structure is, the more and more the channel structure of the bonded sound-absorbing material 1 is, so that the sound-absorbing effect is better. The invention forms micropores and mesopores by utilizing the structures such as the hexagonal ring 12, the defect hole 13, the gaps among the multilayer tubular structures 14 and the like in the carbon nano tube powder 11, thereby greatly increasing the pore canal structure and the specific surface area, achieving the effects of absorbing air molecules and playing a role of the sound absorbing material 1. By controlling the processing process of the defective holes 13, more defective holes 13 can be formed to increase the specific surface area. Specific surface area up to 200m 2 The performance of the sound absorbing material 1 can be substantially satisfied.
Preferably, the specific surface area of the carbon nanotube powder 11 is in the range of 300m 2 /g-1000m 2 And/g. If the specific surface area is too small, it means that the total pore volume of the micro-or meso-pores is insufficient and the sound absorbing performance is limited. Correspondingly, if the specific surface area is too large, it means that the microporous hole structure is too large, which may cause the tubular structure 14 to be too loose, and thus not ensure good structural stability, and cause the mesoporous holes with larger size to have smaller hole number, so that air molecules cannot smoothly circulate. Alternatively, the specific surface area of the carbon nanotube powder 11 may be 300m 2 /g、350m 2 /g、400m 2 And/g, etc., can provide the sound-absorbing material 1 with a sufficient duct structure and ensure structural reliability. Alternatively, the specific surface area of the carbon nanotube powder 11 may be 900m 2 /g、1000m 2 /g、1500m 2 /g、2300m 2 /g、2500m 2 And/g, the larger specific surface area can provide enough micropores, so that the absorption capacity of air molecules is improved.
Alternatively, the sound absorbing material 1 may be formed in a granular, block-like, contoured structure that matches a specific shape. The invention can control the shaping shape of the sound absorbing material 1 according to the sound generating device and the electronic product which are actually applied. For example, the sound absorbing material 1 may be formed into granular pellets, and the carbon nanotube powder 11 and the adhesive may be formed into the granular sound absorbing material 1 by dispersing, pulping, shaping, etc., and then may be filled into the sound emitting device.
The particle size of the particulate sound-absorbing material 1 may be selected to be 100 micrometers to 1000 micrometers (μm). For example, the particle size of the sound absorbing material 1 is 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 700 μm, 900 μm, 1000 μm. After the sound absorbing material 1 particles with smaller particle size are stacked and filled, gaps among the particles can play a role of mesopores or macropores, so that a channel is provided for air circulation. The stacked compact sound generating device is high in overall compactness, and is suitable for small-sized sound generating devices with small volumes and high requirements on sound vibration sensitivity. For example, the sound-absorbing material 1 particles have a particle diameter of between 100 micrometers and 500 micrometers. The particle size of the granular sound absorbing material 1 is not easy to be too small, the structural strength of the particles is easy to cause, the particles can be further broken, and the problems of powder rising, broken porous structure and the like are caused.
In other embodiments, the sound absorbing material 1 may be formed in a rectangular block shape, or a contoured block shape adapted to the specific shape of the cavity in which the sound generating device needs to be provided with the sound absorbing material 1. The invention can bond, fix and dry the slurry according to the shape requirement after the carbon nano tube powder 11 is pulped to form the slurry. Compared with the granular sound absorbing material 1, the sound absorbing material 1 in a block shape has more complete microscopic structural integrity and pore canal structure, and has better performance of absorbing air molecules.
The technical scheme of the invention utilizes the characteristic that the tubular structure 14 of the carbon nano tube powder 11 can be manufactured into a multilayer embedded tube. The number of stacks of tubular structures 14 may be selected to be 2 to 100 layers. The number of stacked tubular structures 14 is not easily excessive, and if the number of layers is excessive, it is difficult for air molecules to flow into micropores and mesopores formed by the tubular structures 14 near the inner layer, thereby wasting the structure. On the other hand, with respect to the tubular structures 14 having a large number of stacked layers, it is also relatively difficult to ensure the structural stability of the tubular structures 14 of the inner layer and the opening ratio of the defective holes 13, and the tubular structures 14 of the inner layer exert limited acoustic effects. Thus, the number of laminations of the multilayer tubular structure 14 employed in the present invention does not exceed 100. Alternatively, the number of layers of the tubular structure 14 is 2, 3, 5, 7, 10, 12, 15, 18, 20, 30, 40, 50, 70, 90, 100, etc. Preferably, the tubular structure 14 having a lamination number of 2 to 20 layers is mainly used in the carbon nanotube powder 11. The stacked number of tubular structures 14 can, on the one hand, have sufficient micropores and mesopores to provide adequate air absorption. For defective cells 13, in embodiments of 2 to 20 layer tubular structure 14, 2 to 5 defective cells 13 communicating along the radial direction of tubular structure 14 can provide radial communicating dimensions of moderate depth, for example 1.5nm, 2.0nm. The plurality of groups of the communicated defect holes 13 can provide uniform and sufficient radial communicated mesopores in the 20 layers, so that the air circulation capacity is improved. On the other hand, the tubular structure 14 in the range of the number of layers is difficult to process, and the utilization rate of the whole pore structure is high, so that the acoustic performance requirement can be met. In the case where a larger pore volume is desired, a higher number of stacked multilayer tubular structures 14 may be employed.
Optionally, in the carbon nanotube powder 11, the arrangement form of carbon atoms includes one or more of a zigzag type, an armchair type and a spiral type. The different arrangement forms of carbon atoms can form an adjusting effect on the size of the micropores, and a plurality of different types of carbon atom arrangement forms are applied to the carbon nanotube powder 11, so that micropores with a relatively wide size range can be formed, and the absorption capacity of the sound absorbing material 1 to air molecules is improved.
Alternatively, the tubular structure 14 of the carbon nanotube powder 11 may be extended in a straight tube shape, an S-shape, a Y-shape, or the like. Several different tubular structures 14 are uniformly distributed in the carbon nanotube powder 11, which can be beneficial to forming a staggered air circulation duct between different areas of the tubular structures 14, and improve the air circulation capability. The tubular structure 14 is generally capable of growing into the three forms described above, without excluding other viable tubular curved forms.
Optionally, the adhesive comprises organic adhesive and inorganic adhesive and other adhesives. The organic adhesive comprises at least one of polyacrylic acid, polyurethane, polyvinyl acetate and epoxy adhesive. The organic adhesive is selected to avoid blocking micropores and mesopores of the carbon nanotube powder 11, and reduce the possibility of damaging the porous property of the carbon nanotube powder 11 due to the adhesive. The inorganic glue comprises at least one of silica sol, aluminum sol, clay and phosphate glue. The inorganic adhesive has good bonding performance, and has a pore structure after drying, thereby being beneficial to the sound absorption effect of the sound absorbing material 1.
Other auxiliary agents may be added during the process of making the sound absorbing material 1. The auxiliary agent comprises one or more of a surfactant, a dispersing agent, a defoaming agent and a stabilizing agent. Wherein the dispersing agent and the defoaming agent can uniformly disperse the carbon nanotube powder 11 and the adhesive in the slurry after mixing them into the slurry, and eliminate bubbles (air) in the slurry. In this way, in the shaping and drying processes, each produced particle of the sound-absorbing material 1 and 1 block of the sound-absorbing material can have a relatively uniform tubular structure 14, and the uniformity of performance and yield of the sound-absorbing material 1 are ensured.
The present invention also provides a sound generating apparatus 20, as shown in fig. 6, comprising: sound-producing unit 20, casing 10 and sound-absorbing material 1 provided by the present invention. The sound generating unit 20 is disposed in the housing 10 and cooperates with the housing 10 to define a front sound cavity 102 and a rear sound cavity 101, and the sound absorbing material 1 is filled in the rear sound cavity 101 and/or the front sound cavity 102. That is, the sound absorbing material 1 may be filled in the front sound chamber 102 or in the rear sound chamber 101. When the sound absorbing material 1 is filled in the front sound cavity 102, damping in the front sound cavity 102 can be increased, whereby distortion spikes of the sound generating device 20 can be reduced, and harmonic distortion and high-frequency noise caused by higher order resonance can be effectively suppressed. When the sound absorbing material 1 is filled in the rear sound cavity 101, the macropores, mesopores and micropores in the sound absorbing material 1 can play a good role in sound absorption, and the virtual volume of the rear sound cavity 101 can be increased, so that the low-frequency effect of the sound generating device can be improved.
Compared with the porous material in the prior art, the sound absorbing material 1 provided by the invention is filled in the sound generating device 20, and on the premise of meeting the acoustic performance, the weight of the whole sound generating device 20 can be effectively reduced relative to the prior art by utilizing the characteristics of small density and light weight of the carbon nano tube powder 11. The sound absorbing material 1 may be made into particles and filled in the sound generating device, or may be made into a block material matched with the front sound cavity 102 or the rear sound cavity 101 of the sound generating device 20 and put into the sound generating device 20, and specifically may be made according to actual requirements, which is not limited in the present invention.
The invention also provides an electronic device, comprising: the sound generating device provided by the invention.
Specifically, in this embodiment, the sound generating apparatus provided in the second aspect of the present invention may be disposed in an electronic device, so as to implement sound generating performance of the electronic device. The sound generating device provided by the invention has good acoustic effect, and meanwhile, the whole weight of the product is reduced, so that the light-weight design requirement is met. The electronic device may be a mobile phone, a notebook computer, a tablet computer, a VR (virtual reality) device, an AR (augmented reality) device, a TWS (real wireless bluetooth) headset, an intelligent sound box, or the like, or may be a car audio device mounted in a vehicle, or the like.
In order to make the technical scheme and the corresponding technical effects of the invention more clear, the invention specifically provides the following preparation process and test to specifically explain the technical scheme.
The present invention will be described with reference to the following processing steps, which are examples of the method for producing the sound absorbing material 1 according to the present invention.
1. Preparation process examples
Firstly, selecting carbon nano tube powder 11 with the average layer number of 10 layers of a tubular structure 14, taking 25g, and dispersing the powder into 75g of deionized water. During the dispersing process, 1g of comb-shaped polystyrene-carboxylic acid modified polymer dispersant is added, and the mixture is mechanically stirred for 30min, so that the slurry is uniformly mixed.
Secondly, adding 3g of acrylic ester organic adhesive into the uniformly mixed slurry, and stirring for 20min to uniformly mix the slurry;
thirdly, conveying the slurry into a spray drying tower, controlling the temperature in the drying tower to be 100 ℃, and drying by utilizing spray droplets to form a granular sound absorbing material 1;
fourth, baking the granular sound absorbing material 1 for 30 minutes at 120 ℃ to obtain a dry granular sound absorbing material 1;
fifth, the particulate sound-absorbing material 1 is subjected to screen sieving to obtain the particulate sound-absorbing material 1 having a particle size in the range of 300 micrometers to 500 micrometers.
The processing technology is used for preparing the granular sound absorbing material 1. In the third step, the sound-absorbing material 1 block having a specific shape may be supported by other shaping means. The tubular structure 14 of the carbon nanotube powder 11 selected in the process has an average lamination amount of 10 layers, and the lamination amount can be selected and adjusted according to application requirements.
2. Bulk density contrast test
And comparing and testing the bulk density of the sound absorbing material 1 particles obtained by the preparation process and the bulk density of the existing conventional silicon-aluminum molecular sieve sound absorbing particles by using a molecular sieve bulk density tester.
Test data are shown in table 1 below:
TABLE 1
Under the condition of stacking particles with the same volume, the mass of the particles of the sound absorbing material 1 of the carbon nano tube powder 11 provided by the invention is obviously lower than that of the sound absorbing particles of the silicon-aluminum molecular sieve in the center of the prior art. The density of the silica alumina molecular sieve sound absorbing material 1 is about 4.8 times that of the sound absorbing material 1 of the present invention, and the mass is about 5 times that of the sound absorbing material 1 of the present invention. The sound absorbing material 1 provided by the invention obviously improves the weight problem of the product and meets the light and thin related requirements of electronic products.
3. Filling sound generating device performance test
According to the test, the sound-absorbing material 1 provided by the invention and the sound-absorbing material 1 in the prior art are filled into the sound-producing device for test with the same model, and then the acoustic performance of the sound-producing device is tested, so that the performance difference between the sound-absorbing material 1 and the sound-absorbing material 1 in the prior art is obtained.
Firstly, taking 0.2ml of the sound-absorbing material 1 particles prepared by the preparation process, and filling the sound-absorbing material 1 particles into a rear sound cavity of the sound-producing device. A modified sound generating apparatus in which 10 sound absorbing materials 1 were filled was prepared as example 1.
Secondly, taking 0.2ml of the existing conventional sound absorbing material 1 particles, and filling the existing sound absorbing material 1 particles into a rear sound cavity of the sound generating device. As comparative example 1, 10 existing sound emitting devices filled with the existing sound absorbing material 1 were prepared.
Third, 10 sound emitting devices of the same specification were used as comparative sound emitting devices without filling the sound absorbing material 1, and comparative example 2 was obtained.
3.1 resonant frequency test
Three sets of test pieces of the "improved sound emitting device" example 1, the "existing sound emitting device" comparative example 1, and the "comparative sound emitting device" comparative example 2 were subjected to the test of the resonance frequency F0, and the F0 results of the sound emitting devices of the respective sets were compared.
The test data are shown in table 2 below:
TABLE 2
As shown in fig. 5 and table 2, the improved sound generating apparatus of embodiment 1 has a significant improvement in acoustic performance, and the resonance frequency is the lowest, which is 780 hz. Which lowers the resonance frequency by 170 hz compared to comparative example 2 without any improvement. This part of the improvement effect is provided by the improved carbon nanotube powder 11 sound absorbing material 1 provided by the present invention. Compared with the existing sound production device adopting the existing silicon-aluminum molecular sieve porous material, the performance of the device is improved to a certain extent.
It can be seen that the sound absorbing material 1 provided by the present invention can replace the sound absorbing material 1 of the prior art in performance.
3.2 high temperature high humidity resonant frequency test
Two sets of test pieces of the "improved sound emitting device" example 1, and the "existing sound emitting device" comparative example 1 described above were subjected to specific environmental tests. The two groups of devices are placed in an environment with 65 ℃ and 95% RH (humidity), and a white noise signal with the voltage of 3.18V is introduced, so that the devices continuously work for 120 hours. After that, the resonant frequencies of the two sets of devices are tested.
The test data are shown in Table 3 below:
| experimental group | F0 test/Hz before experiment | Post-experiment F0 test/Hz | △F0/Hz |
| Example 1 | 780 | 803 | 23 |
| Comparative example 1 | 800 | 845 | 45 |
TABLE 3 Table 3
Example 1 was subjected to environmental operation test, the amount of change in the resonance frequency thereof was 23 Hz, and the amount of change in F0 of comparative example 1 was 45Hz. Obviously, the sound absorbing material 1 provided by the invention can still keep good performance under the working environment of high temperature and high humidity, and realizes high-sensitivity adsorption and desorption effects on air molecules. The occurrence rate of the situation that holes are blocked, organic molecules or water molecules occupy micropores and mesopores is low because of high temperature and high humidity, and the performance attenuation is less. The conventional silicon-aluminum molecular sieve sound absorbing material 1 has more obvious performance attenuation, and has weaker reliability and stability compared with the embodiment 1.
3.3 Low temperature resonant frequency test
Two sets of test pieces of the "improved sound emitting device" example 1, and the "existing sound emitting device" comparative example 1 described above were subjected to specific environmental tests. The two sets of devices were placed in an environment of-20 degrees celsius (subzero), 2.5V BFPP signals (industry specific test signals) were introduced, and operated continuously for 24 hours. After that, the devices of example 1 and comparative example 1 were subjected to a test of resonance frequency.
The test data are shown in Table 4 below:
| experimental group | F0 test/Hz before experiment | Post-experiment F0 test/Hz | △F0/Hz |
| Example 1 | 780 | 815 | 35 |
| Comparative example 1 | 800 | 856 | 56 |
TABLE 4 Table 4
Example 1 was subjected to environmental operation test, the amount of change in the resonance frequency was 35 Hz, and comparative example 1 was 56Hz in F0. The sound absorbing material 1 provided by the invention can still keep good stability under a low-temperature working environment, and the performance decay range is controllable. The occurrence rate of hole collapse and fracture caused by low temperature is limited, and the performance can be maintained in a low-temperature severe environment.
The foregoing embodiments mainly describe differences between the embodiments, and as long as there is no contradiction between different optimization features of the embodiments, the embodiments may be combined to form a better embodiment, and in consideration of brevity of line text, no further description is given here.
While certain specific embodiments of the invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.
Claims (15)
1. A sound absorbing material, comprising:
the carbon nano tube powder comprises a plurality of layers of coaxially arranged tubular structures, the number of layers of the tubular structures ranges from 2 to 100, the tube wall of each layer of the tubular structure comprises a plurality of hexagonal rings formed by six carbon atoms, defect holes formed by surrounding more than six carbon atoms are formed in the tube wall of the tubular structure, and the average pore diameter of the defect holes ranges from 0.5nm to 10nm; wherein the hexagonal ring forms micropores for ventilation, and the defective holes and gaps among the multiple layers of tubular structures form micropores and/or mesopores for ventilation;
and the adhesive is used for bonding the plurality of carbon nano tube powder bodies to form the sound absorbing material.
2. The sound absorbing material of claim 1 wherein at least said hexagonal ring is spaced between two of said defective cells.
3. The sound absorbing material according to claim 1, wherein the defective holes are formed on the wall of the tubular structure by an opening process;
the perforating process comprises the following steps:
at least one of an electron beam irradiation process, a lithography process, or a gas plasma etching process.
4. The sound absorbing material of claim 1, wherein in the multilayer tubular structure, at least a portion of the defective holes on the tubular structure of adjacent layers communicate in a radial direction of the tubular structure.
5. The sound absorbing material of claim 4, wherein in a plurality of layers of said tubular structure, at least a portion of said defective cells in at least three layers of said tubular structure are in unitary communication.
6. The sound absorbing material according to claim 4, wherein in the multilayer tubular structure, a depth of communication of the plurality of defective holes communicating in a radial direction of the tubular structure in the radial direction of the tubular structure is 0.5nm or more.
7. The sound absorbing material according to claim 1, wherein in the plurality of layers of the tubular structures, a spacing between adjacent two layers of the tubular structures is greater than or equal to 0.3nm;
And/or the distance between two adjacent layers of the tubular structures is less than or equal to 1.5nm.
8. The sound absorbing material according to claim 1, wherein the mass ratio of carbon element in the carbon nanotube powder is 90% or more;
and/or the mass ratio of oxygen element in the carbon nano tube powder is less than or equal to 5%.
9. The sound absorbing material according to claim 1, wherein the aspect ratio of the tubular structure of the carbon nanotube powder ranges from 500 to 50000.
10. The sound absorbing material of claim 1, wherein the carbon nanotube powder has a tap density in the range of 0.05g/cm 3 -0.1g/cm 3 。
11. The sound absorbing material according to claim 1, wherein the specific surface area of the carbon nanotube powder is in a range of 200m 2 /g-2500m 2 /g。
12. The sound absorbing material of claim 1, wherein the sound absorbing material is in the form of particles, and the sound absorbing material has a particle size in the range of 100 microns to 1000 microns;
alternatively, the sound absorbing material may be in the form of a block.
13. The sound absorbing material of claim 1 wherein the number of layers of the multi-layered tubular structure ranges from 2 to 20 layers.
14. A sound emitting device, comprising:
A sound producing unit, a casing, and the sound absorbing material of any one of claims 1 to 13;
the sound generating unit is arranged in the shell and is matched with the shell to define a front sound cavity and a rear sound cavity, and the sound absorbing material is filled in the rear sound cavity and/or the front sound cavity.
15. An electronic device, comprising: the sound emitting device of claim 14.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310798767.2A CN116847254A (en) | 2023-06-30 | 2023-06-30 | Sound absorbing material, sound generating device and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310798767.2A CN116847254A (en) | 2023-06-30 | 2023-06-30 | Sound absorbing material, sound generating device and electronic equipment |
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