CN109448688B - Active carbon sound-absorbing material and sound-producing device - Google Patents
Active carbon sound-absorbing material and sound-producing device Download PDFInfo
- Publication number
- CN109448688B CN109448688B CN201811447854.9A CN201811447854A CN109448688B CN 109448688 B CN109448688 B CN 109448688B CN 201811447854 A CN201811447854 A CN 201811447854A CN 109448688 B CN109448688 B CN 109448688B
- Authority
- CN
- China
- Prior art keywords
- sound
- activated carbon
- absorbing material
- particles
- pore
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
- G10K11/165—Particles in a matrix
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
- G10K11/168—Plural layers of different materials, e.g. sandwiches
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention discloses an active carbon sound-absorbing material and a sound-producing device. The active carbon material comprises three elements of carbon, hydrogen and oxygen, wherein the mass ratio of the carbon element is more than or equal to 60 wt%, the mass ratio of the carbon to the oxygen in the active carbon sound-absorbing material is more than or equal to 3, the active carbon sound-absorbing material contains a two-dimensional graphite layer and/or a three-dimensional graphite microcrystal, the active carbon sound-absorbing material has a loose pore structure inside, the pore structure comprises nano-scale micropores and mesopores, and the pore diameter of the mesopores is more than that of the micropores. One technical effect of the present invention is that the activated carbon sound-absorbing material can be used to reduce the resonance frequency of a sound-emitting device.
Description
Technical Field
The invention relates to the technical field of acoustics, in particular to an active carbon sound-absorbing material and a sound-generating device.
Background
In recent years, consumer electronics have been developed rapidly, and electronic products such as mobile phones, tablet computers, earphones and the like are widely used in various fields by consumers. With the gradual development of the related art, the performance requirements of the electronic products are higher and higher by consumers. The skilled person will make improvements to the components of the electronic product to meet the needs of performance development.
Sound emitting devices are important acoustic devices in electronic products for converting electrical signals into sound signals. The resonance frequency of the sound generating device is an important acoustic performance index, and the reduction of the resonance frequency of the sound generating device is beneficial to improving the acoustic effect of the sound generating device.
The resonance frequency refers to the vibration frequency of the sounding device gradually increased from a low frequency range, and the vibration intensity reaches the strongest vibrationAlternatively, the impedance characteristic of the sound generating device is measured, and when the impedance value reaches a maximum value for the first time, the corresponding vibration frequency is referred to as the resonance frequency or resonant frequency of the speaker unit, i.e., f0。
How to reduce the resonance frequency of the sound generating device to improve the acoustic performance is a main research direction for those skilled in the art.
Disclosure of Invention
It is an object of the present invention to provide a new solution for reducing the resonance frequency of a sound generating device.
According to a first aspect of the present invention, an activated carbon sound absorption material is provided, the activated carbon material includes three elements of carbon, hydrogen and oxygen, wherein the mass ratio of the carbon element is greater than or equal to 60 wt%, the mass ratio of carbon to oxygen in the activated carbon sound absorption material is greater than or equal to 3, the activated carbon sound absorption material contains a two-dimensional graphite layer and/or three-dimensional graphite microcrystals, the activated carbon sound absorption material has a loose pore channel structure inside, the pore channel structure includes nano-scale micropores and mesopores, and the pore diameter of the mesopores is greater than the pore diameter of the micropores.
Optionally, the carbon to oxygen mass ratio is greater than 4.
Optionally, the activated carbon sound absorbing material is made of amorphous activated carbon particles, and the amorphous activated carbon particles contain a disordered layer structure formed by random accumulation of molecular fragments of two-dimensional graphite layer structures and/or three-dimensional graphite microcrystals.
Optionally, the amorphous activated carbon particles are one or more of spherical, spheroidal, platelet, and rod shaped.
Optionally, the amorphous activated carbon particles have a particle size in the range of 0.1 to 100 microns.
Optionally, the amorphous activated carbon particles comprise hydrophobic amorphous activated carbon particles.
Optionally, the activated carbon sound absorbing material is configured to have an adsorption amount of nitrogen gas of 0.05mmol/g or more.
Optionally, the nanoscale pore channel structure includes micropores and mesopores, the pore diameter range of the micropores is 0.5-2 nm, and the pore diameter range of the mesopores is 2-20 nm.
Optionally, the pore size of the micropores ranges from 0.7 nm to 1.3nm, and the pore size of the mesopores ranges from 2nm to 3.5 nm.
The present invention also provides a sound generating apparatus, comprising:
a housing having an accommodating chamber formed therein;
a vibration assembly disposed in the housing;
the active carbon sound-absorbing particles are arranged in the accommodating cavity.
According to one embodiment of the present disclosure, activated carbon sound absorbing particles may be used to reduce the resonant frequency of a sound generating device.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, 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 table comparing the carbon-to-oxygen ratio of the sound-absorbing material with the structural characteristics and the effect of reducing the resonant frequency;
FIG. 2 is a graph of vibration frequency versus electrical impedance of the sound absorbing material of activated carbon with different carbon-to-oxygen ratios provided by the present invention;
FIG. 3 is a graph showing the cumulative pore volume at a carbon-to-oxygen ratio of 9 for the sound-absorbing material of activated carbon according to the present invention;
FIG. 4 is a table comparing the particle size of amorphous activated carbon particles with the effect of reducing the resonance frequency, according to the present invention;
FIG. 5 is a graph showing the vibration frequency and the electrical impedance of amorphous activated carbon particles having different particle diameters according to the present invention.
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, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to those 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 particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
The invention provides an active carbon sound-absorbing material which contains a two-dimensional graphite layer and/or three-dimensional graphite microcrystals, wherein the active carbon sound-absorbing material formed by stacking the graphite layer and the microcrystals is internally provided with a loose pore channel structure. The pore channel structure comprises nanometer micropores and mesopores. The pore diameter of the mesopores is larger than that of the micropores. The pore structure in the active carbon sound-absorbing material can enable the active carbon sound-absorbing material to quickly absorb and release air. The carbon element is used for providing support, and further a frame and a pore channel structure are formed.
The verification of the invention proves that the volume of the box body can be equivalently expanded by putting the active carbon sound-absorbing material into the box body of the sound-producing device through the absorption and release effects on air, so that the volume of the cavity is expanded by a time, and a is larger than 1.
Resonance frequency f of sound generating unit0Can be expressed by the following equation:
in the above equation, MmsIs the mass of the sound-generating unit, CmsIs the equivalent compliance of the sound generator unit.
After the sound generating device unit is assembled in the box body of the sound generating device, the resonant frequency f of the sound generating device01Can be expressed by the following equation:
in the above equation, CmsIs the air acoustic compliance of the volume of the housing of the sound generating device.
After the sound-absorbing particles made of the activated carbon are placed in the box body of the sound-generating device, the resonant frequency f of the sound-generating device is at the moment02Expressed by the following equation:
as described above, the volume of the case is equivalently enlarged by a times (a) by the activated carbon sound absorbing material>1) In the direction of f02Is less than f01。
In the case of a sound-generating device, the forced vibration of the particles consumes the energy of the sound waves, which is equivalent to an increase in the acoustic compliance of the air in the volume of the case, thus reducing the resonance frequency f02。
The active carbon sound-absorbing material provided by the invention can be used in sound-producing devices such as earphones, speakers, sound boxes and the like. For example, the sound absorbing material made of activated carbon is placed in the rear sound cavity of the sound generating device, and the volume of the rear sound cavity is virtually enlarged, so that the resonance frequency of the sound generating device is reduced. Thereby achieving the effect of improving the acoustic performance of the sound generating device.
In an alternative embodiment, the carbon element content in the activated carbon sound absorbing material is greater than or equal to 60 wt%. The mass ratio of carbon to oxygen in the activated carbon sound-absorbing material is greater than or equal to 3. The carbon element plays a role in forming a frame and constructing the active carbon sound-absorbing materialThe function of the pore structure. The inventors of the present invention have developed that the carbon-oxygen mass ratio is preferably set to be greater than 3. If the carbon-oxygen mass ratio is too low, the pore channel structure formed in the active carbon sound-absorbing material is too loose, and the pore diameter of the pore channel structure is enlarged. The pore diameter of the pore channel structure is increased, so that the accumulated pore volume of the active carbon sound-absorbing material is reduced, and the capacity of absorbing and air is reduced. This phenomenon can cause the reduction of the magnification of the equivalent volume of the sound-absorbing material of the activated carbon to the box body of the sound-generating device, and further cause the reduction of the resonant frequency f0The effect of (c) is reduced. Therefore, the preferred carbon to oxygen mass ratio is greater than 3.
The carbon to oxygen mass ratio is preferably greater than 5. When the carbon-oxygen mass ratio is in the above range, the effect of lowering the resonance frequency is most excellent. At the moment, the diameter of the pore channel structure is smaller, so that the rapid air absorption and release effects are more favorably realized. In a specific embodiment of the present invention, the carbon to oxygen mass ratio may be 3, 5, 15, 20.
In another alternative embodiment, the carbon element content of the activated carbon sound absorbing material is greater than or equal to 60 wt%. The mass ratio of hydrocarbon in the activated carbon sound-absorbing material is greater than or equal to 11. Alternatively, the activated carbon sound-absorbing material is formed by carbonizing a mineral-based material, a plant-based material, a synthetic material, or the like at a high temperature. The specific gravity of the raw material remained in the active carbon sound-absorbing material is different according to different carbonization processes. The smaller the mass ratio of hydrocarbon, the smaller the percentage mass of other impurities of the remaining raw material. Correspondingly, the more perfect the pore structure in the material is, the larger the cumulative pore volume of the pore structure is, and the better the adsorption capacity to air is.
Preferably, the hydrocarbon ratio is greater than 13. Within the above range, the activated carbon sound-absorbing material exhibits the most excellent effect of lowering the resonance frequency. For example, the sound absorbing materials of activated carbon having the mass ratios of 10, 11, 13 and 20 of carbon to hydrogen are respectively 0.37g/cm in cumulative pore volume3、0.45g/cm3、0.62g/cm3And 0.81g/cm3In the active carbon sound-absorbing material having the same mass, the resonance frequency f0The reduction effect of (2) is optimal.
For the pore channel structure, the micropores are mainly used for absorbing and containing air molecules, and the mesopores can contain the air molecules and also play a role in enabling the air molecules to rapidly enter and exit the micropores, so that the active carbon sound-absorbing material has good air pressure change response capability. FIGS. 1 and 2 show the micropore, mesopore, cumulative pore volume and resonant frequency f with different carbon-oxygen mass ratios as variable factors0The reducing effect of (1). As can be seen from FIG. 2, as the vibration frequency increases, the impedance increases and then decreases, and the frequency at which the impedance reaches a maximum is the resonance frequency (f)0). With the increase of the carbon-to-oxygen mass ratio, the resonant frequency f0The gradual decrease shows that the higher the carbon-oxygen mass ratio is, the better the effect of reducing the resonant frequency is achieved by the active carbon sound-absorbing material. FIG. 3 is a graph of cumulative pore volume for a carbon to oxygen mass ratio of 15. As shown by the solid line in FIG. 3, the pore diameters of the micropores are mainly distributed in the range of 0.7 to 1.3nm, the cumulative pore volume of the micropores having a pore diameter of 2nm or less is 0.53ml/g, the pore diameters of the mesopores are mainly distributed in the range of 2 to 3.5nm, and the total cumulative pore volume is 0.83 ml/g.
Preferably, mesopores with a pore diameter in the range of 2-3.5nm account for 60-65% of the total mesopore content. When the pore diameters of a large number of mesopores are concentrated in a narrow range, the pore channel perfection degree of the mesopores is higher, the accumulated pore volume of the mesopores tends to rise, and the adsorption-desorption effect on air is better. Therefore, the activated carbon sound-absorbing material can show a better equivalent expansion effect. In a preferred embodiment, the mesopores with a pore diameter of 2-3.5nm are 60-65% of the total mesopores, thereby achieving the above-mentioned effect of improving adsorption and desorption performance. If the pore diameters of a large number of mesopores are concentrated in the pore diameter range of more than 5nm, the communication between the mesopores and the micropores is not smooth due to a large difference in pore diameter between the mesopores and the micropores. And further causes the resistance of air molecules entering and exiting the micropores and rapidly flowing in the mesopores to be increased, thereby influencing the acoustic performance of the active carbon sound-absorbing material.
Preferably, the activated carbon sound absorbing material is configured to have an adsorption amount of nitrogen gas of 0.05mmol/g or more. Thereby guarantee that active carbon sound absorbing material has sufficient absorption and desorption properties to the air to satisfy the needs in equivalent dilatation cavity space.
For two-dimensional graphite layers and/or three-dimensional graphite microcrystals contained in the activated carbon material, the structure of a pore channel formed in the material is mainly influenced. The content of the two structures in the material is more, and after the material is subjected to a processing procedure of a carbonization process, the formed pore channel structure is more uniform, and the pore diameter of the pore channel structure is smaller, so that the active carbon sound-absorbing material can generate a good effect of reducing the resonance frequency.
Alternatively, the activated carbon sound absorbing material may be made of amorphous activated carbon particles. The amorphous activated carbon particles contain a disordered layer structure formed by stacking molecular fragments of two-dimensional graphite layers and/or three-dimensional graphite microcrystals in a random form. A large number of irregular bonds are present on the edges of the two-dimensional graphite layer structure and the three-dimensional graphite crystallites. Irregular bonds can form tight connection between the two-dimensional graphite layer structure and the three-dimensional graphite microcrystal and form a pore channel structure by interweaving. The valence electron of carbon has sp2Hybrid orbital and sp3And hybridizing the orbitals to form a hexagonal carbon net plane. The active carbon particles formed by the random accumulation can form a fine and rich pore channel structure so as to meet the structural requirements of the active carbon sound-absorbing material on the pore channel structure.
Preferably, the particle size of the two-dimensional graphite layer and the three-dimensional graphite crystallite is less than 30 nm. If the particle sizes of the two-dimensional graphite layer and the three-dimensional graphite microcrystal are within the range, uniform and fine pore channel structures can be formed better after random accumulation. On one hand, the air absorption and release performance of the active carbon sound absorption material is better facilitated. On the other hand, the structural uniformity and stability of the amorphous activated carbon particles can be improved, and the structural strength of a product made of the activated carbon sound-absorbing material is improved.
Alternatively, the amorphous activated carbon particles themselves may be in one or more of a spherical, spheroidal, platelet, rod-shaped structure. For example, after the activated carbon sound absorption particles are formed by bonding spherical carbon particles, a more uniform and finer pore structure can be formed among the carbon particles, and the acoustic performance of the activated carbon sound absorption particles is further improved. The sheet-shaped carbon particles can improve the structural stability of the sound-absorbing active carbon particles and reduce the risks of dusting and damage. Meanwhile, as the carbonization process of the flake amorphous activated carbon particles is simple and convenient and the cost is lower, the flake amorphous activated carbon particles are preferred from the industrial application perspective.
Optionally, the amorphous activated carbon particles have a particle size in the range of 0.1 to 100 microns. The particle size of the amorphous activated carbon particles affects the bulk density thereof, and the size of the bulk density affects the performance of the air-absorbing performance.
If the particle diameter of the amorphous activated carbon particles is too small, the bulk density is significantly increased. At a certain volume, the mass of the amorphous activated carbon particles which can be filled is relatively reduced, resulting in a reduction in the performance of lowering the resonance frequency. On the other hand, if the particle diameter of the amorphous activated carbon particles is too large, the bulk density is significantly reduced. At a certain volume, an excessive bulk density leads to a reduction in the energy of the sound waves consumed when the particles in the space are forced to vibrate, equivalent to the aeroacoustic compliance (C) in the volume of the box of the sound-generating devicema) The decrease also results in a reduction in performance of lowering the resonance frequency.
Preferably, the amorphous activated carbon particles have a particle size ranging from 0.2 to 20 μm, and the prepared activated carbon sound-absorbing particles can show a good reduction of the resonance frequency f0The effect of (1).
Accordingly, the bulk density of the amorphous activated carbon particles may be selected within a range of 0.15 to 0.8g/cm3Preferably, the bulk density is 0.25 to 0.55g/cm3. The bulk density can also be adjusted by factors such as the shape of the amorphous activated carbon particles, the carbon content and the like.
FIGS. 4 and 5 show the bulk density and the resonance frequency f of amorphous activated carbon particles having particle diameters of 0.05, 1, 15 and 30 μm, respectively0The degree of reduction of (c). As shown in FIG. 4, when the particle diameters of the amorphous activated carbon particles were 1 and 15 μm, the bulk density thereof was expressed as 0.51g/cm3And 0.33g/cm3Simultaneously exhibits a resonant frequency f0The degree of reduction was 169Hz and 175 Hz. As shown in figure 5 of the drawings,as the frequency of vibration increases, the impedance increases and then decreases. As the particle size increases, its pair f0The effect of decrease of (a) shows a tendency of increasing first and then decreasing. It can be seen that when the particle diameter is too large or too small, the resonance frequency f0The degree of reduction is correspondingly reduced.
In particular, for the channel structure including micropores and mesopores, which is provided in the amorphous activated carbon particles, the pore diameter of the micropores is in the range of 0.5-2 nm, wherein the pore diameter of most micropores is between 0.7-1.3 nm. The pore size of the mesopores ranges from 2 to 20 nanometers, and preferably, the pore size of most of the mesopores is between 2 to 3.5 nanometers.
In the amorphous activated carbon particles, the pore diameter of the micropores is limited to a smaller size, so that the particles can contain a sufficient number of micropores, on one hand, the total accumulated pore volume of the particles is increased, and on the other hand, the adsorption capacity of the particles to air molecules can be improved. A large number of micropores with small pore diameters can adsorb a large number of air molecules, so that the acoustic performance of the prepared active carbon sound-absorbing particles is improved. The reason why the pore diameter of the mesopores is limited within the above range is to provide a sufficient flow space for the air molecules when the air molecules need to be rapidly sucked into or released from the micropores, so that the air molecules can rapidly move, and the air blockage and the situation in the micropores are reduced. On the other hand, if the pore diameter of the mesopores is too large, the cumulative pore volume of the amorphous activated carbon particles is reduced, resulting in a decrease in the air absorption performance of the entire particles.
Preferably, the amorphous activated carbon particles have a cumulative pore volume in the range of 0.6 to 5cm3(ii) in terms of/g. The cumulative pore volume of the amorphous activated carbon particles significantly affects the effect of the sound-absorbing particles in reducing the resonance frequency. Less than 0.4cm in cumulative pore volume3At the time of/g, the adsorption and desorption capacity of the sound-absorbing particles to air molecules is obviously reduced. The lower pore volume causes that air molecules can not smoothly enter and exit the amorphous activated carbon particles, and the particles can not absorb a large amount of air molecules. And when the cumulative pore volume rises to 0.7cm3After the concentration of the mesoporous particles is increased, the content of the mesoporous particles is increased, so that the particles meet the requirement of rapid entrance and exit of air molecules. The sound of adsorbing and desorbing air moleculesThe speed is obviously increased, and the equivalent capacity expansion ratio of the box body of the sound production device is obviously increased. After the cumulative pore volume continues to increase, the content of micropores also increases correspondingly, and the amount of air molecules adsorbed by the particles also increases significantly. Therefore, the effect of reducing the resonant frequency can be better played.
In particular, the cumulative pore volume of the amorphous activated carbon particles is not likely to be too high, and if the pore volume is too high, problems such as poor adhesion and a decrease in the structural reliability of the activated carbon sound-absorbing particles are caused. The increase in the amount of the binder due to this problem may adversely decrease the content of amorphous activated carbon particles in the activated carbon sound-absorbing granules, and adversely affect the acoustic properties of the granules.
Preferably, the amorphous activated carbon particles have a cumulative pore volume in the range of 0.8 to 2cm3(ii) in terms of/g. Within this range, the activated carbon sound-absorbing particles can exhibit good acoustic properties, and problems such as a reduction in structural reliability and a reduction in the content of amorphous activated carbon particles do not occur.
Further, the ratio of the cumulative pore volume of the micropores to the cumulative pore volume of the mesopores ranges from 0.05 to 20. Preferably, the ratio of the two ranges from 0.1 to 5, for example, the above ratio may be selected to be 1 or 2. For different active carbon sound-absorbing particles with the same quality, the higher the ratio of the micropore accumulated pore volume to the mesopore accumulated pore volume is, the stronger the adsorption and desorption performances of air molecules are. The performance characteristic is mainly embodied in that the micropores can provide larger volume for absorbing air molecules, so that the equivalent capacity expansion ratio of the box body of the sound generating device is larger. The better the effect of lowering the resonance frequency. However, in the technical solution of the present invention, the ratio of the two is not more than 20. The effect of the sound absorption particles of the activated carbon on reducing the resonance frequency is reduced sharply after the ratio exceeds 20. The reason for this is that the above ratio is too large, which means that the content of micropores is too high, and the size of most pore structures in the sound-absorbing active carbon particles is too small, thereby hindering the convection of air and preventing air molecules from entering and exiting the sound-absorbing active carbon particles. And thus affects the propagation of the acoustic wave, which is coupled to f0The lowering effect of (c) is drastically reduced.
Optionally, the amorphous activated carbon particleThe specific surface area of the particles is in the range of 1000-3000m2(ii) in terms of/g. Preferably, the amorphous activated carbon particles have a specific surface area in the range of 1500-2(ii) in terms of/g. Within a certain range, the specific surface area of the amorphous activated carbon particles has a positive correlation with the cumulative pore volume thereof. The larger the specific surface area, the larger the cumulative pore volume. In a proper range, the larger the cumulative pore volume is, the larger the adsorption capacity of the amorphous activated carbon particles to air is, and the larger the adsorption capacity to f0The better the reduction of (c).
Preferably, the amorphous activated carbon particles comprise hydrophobic amorphous activated carbon particles. The surface of the hydrophobic activated carbon particles does not contain hydrophilic groups such as carboxyl, hydroxyl, and amino groups. The amorphous activated carbon particles with hydrophobicity can reduce the impurity content in the activated carbon sound-absorbing particles, and the hydrophobicity of the particles can ensure that the pore channel structure of the particles can not adsorb an adhesive when the processing technologies such as bonding, granulation and the like are carried out. In addition, to the sound granule finished product is inhaled to active carbon, its hydrophobicity can reduce the condition that the granule absorbs the steam in the air, avoids liquid to cause the pore structure of sound granule is inhaled to active carbon to block up the scheduling problem. The risk of failure of the sound-absorbing particles of the activated carbon due to water absorption and adhesives in the long-term use process is reduced.
The invention also provides an active carbon sound-absorbing particle, which is formed by mixing and granulating amorphous carbon particles and a high-molecular polymer adhesive. The high molecular polymer adhesive bonds powdery amorphous activated carbon particles into activated carbon sound-absorbing particles which are convenient to fill and apply. In particular, micron-sized pore channels can be formed among the amorphous activated carbon particles which are bonded together, so that the air absorption and release capacity of the activated carbon sound absorption particles is further improved.
Optionally, the activated carbon sound absorbing particles themselves have a particle size in the range of 50 to 1000 microns. The particle size of the active carbon sound-absorbing particles can influence the stacking density, the adhesive content and other factors of the particles, and further influence the reduction of the resonant frequency f0The effect of (1).
If the particle size of the sound-absorbing activated carbon particles is less than 50 μm, the strength of the sound-absorbing activated carbon particles themselves is relatively decreased. After the sound-absorbing particle is applied to a box body of a sound-generating device, the vibration of air and the change of air pressure can more easily cause the dust-absorbing particle of the active carbon to be pulverized and broken. Such problems can seriously affect the effectiveness of the particles to reduce the resonant frequency and may have an effect on the reliability of the sound generating device.
And if the particle size of the sound-absorbing particles of the activated carbon is larger than 1000 micrometers, the volume of the particles is relatively large, and gaps between the particles are obviously increased. When the active carbon sound-absorbing particles are placed in a box body of a sound production device, the stacking density of the particles is obviously reduced. Accordingly, the amount of activated carbon sound-absorbing particles that can be filled in a unit volume of the cabinet is relatively decreased. Therefore, the substance capable of generating the virtual volume expansion effect is reduced, and the resonance frequency f is lowered0The effect of (a) is weakened.
Therefore, the particle size range of the active carbon sound absorption particles is kept within the range of 50-1000 microns, and the resonance frequency f can be basically reduced0The performance requirements of (a). Preferably, the particle size of the activated carbon sound-absorbing particles themselves is in the range of 100-450 microns. For example, 200, 250 microns in particle size. Within the above preferred range, the resonance frequency f is lowered0The performance of (2) reaches an optimum level. The particle size range of the active carbon sound absorption particles and the particle size range of the amorphous active carbon particles can be designed in a matching mode. For example, optionally, the activated carbon sound absorbing particles have a particle size in the range of 50 to 1000 microns and the amorphous activated carbon particles have a particle size in the range of 0.1 to 100 microns. Preferably, the particle size of the activated carbon sound absorption particles is in the range of 100-450 microns, and the particle size of the amorphous activated carbon particles is in the range of 0.2-20 microns. By controlling the particle size, the effects of optimizing the bulk density and lowering the resonance frequency can be achieved.
The invention also provides an optional type of the high molecular polymer adhesive, and the high molecular polymer adhesive is configured to ensure the shaping and the structural stability of the sound-absorbing particles of the activated carbon, and can not damage and block the pore channel structure in the amorphous activated carbon particles as far as possible.
Optionally, the high molecular polymer adhesive comprises at least one of polyacrylic acid (ester), polyvinyl alcohol, polystyrene, polyvinyl acetate, latex and polyolefin adhesives. The high molecular polymer adhesive can also be taken out from the sound-absorbing particles through a degreasing process after the sound-absorbing particles are subsequently prepared into the active carbon sound-absorbing particles, so that more abundant pore channel structures are left. Preferably, the mass ratio of the polymer binder in the activated carbon sound-absorbing particles is in the range of 1-10 wt%. If the content of the polymer binder is too high, the amount of the amorphous activated carbon particles is decreased, and the air absorption performance is affected. If the content of the high molecular adhesive is too low, the prepared active carbon sound-absorbing particles are easy to cause the problems of dusting, crushing and the like, so that the structural reliability is reduced.
In a sound production device, the activated carbon sound absorption particles have high absorption capacity and absorption coefficient for nitrogen molecules and other air molecules under the environment of approximately one atmospheric pressure. The active carbon sound absorption particles provided by the invention are placed in the rear sound cavity of the micro-speaker, so that the middle and low frequency resonance frequency f of the micro-speaker can be effectively realized0The reducing effect is in the range of 0.5-4.5 Hz/mg. The activated carbon sound absorbing particles are capable of altering the acoustic compliance of a gas contained in the substantially enclosed rear acoustic cavity.
The active carbon sound absorption particles provided by the invention are suitable for adjusting the resonant frequency of a substantially closed cavity. The box body of the sound-absorbing active carbon particles filled in the sound-generating device can be equivalent to increasing the damping of the sound-generating device, thereby reducing the resonance strength. Thereby reducing the peak value of the electrical impedance of the sound generating device.
On the other hand, the adsorption and desorption effects of the activated carbon sound-absorbing material on air molecules can be repeatedly performed, and the phenomenon of performance reduction caused by repeated adsorption and desorption of the air molecules is avoided. The active carbon sound-absorbing material can be repeatedly used for a long time.
The invention also provides a sound production device. The sound production device comprises a shell, a vibration assembly and the activated carbon sound absorption particles. An accommodating cavity is formed in the housing, and the vibration assembly is disposed in the housing. The active carbon sound-absorbing particles are arranged in the accommodating cavity.
The vibration component divides the containing cavity into a front sound cavity and a rear sound cavity, the front sound cavity is communicated with the sound outlet hole in the shell, and the rear sound cavity is basically a closed space. The activated carbon sound-absorbing particles may be disposed in the rear acoustic cavity. Of course, the present invention is not limited to placing the activated carbon sound absorbing particles in the front acoustic chamber to adjust the sound and airflow of the front acoustic chamber.
Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present 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 (9)
1. The active carbon sound-absorbing material is characterized by comprising three elements of carbon, hydrogen and oxygen, wherein the mass ratio of the carbon element is more than or equal to 60 wt%, the mass ratio of the carbon to the oxygen in the active carbon sound-absorbing material is more than 4, the active carbon sound-absorbing material contains a two-dimensional graphite layer and/or a three-dimensional graphite microcrystal, the active carbon sound-absorbing material is internally provided with a loose pore structure, the pore structure comprises nano-scale micropores and mesopores, and the pore diameter of the mesopores is more than the pore diameter of the micropores.
2. The activated carbon sound-absorbing material according to claim 1, wherein the activated carbon sound-absorbing material is made of amorphous activated carbon particles having a turbostratic structure formed by random stacking of molecular fragments of two-dimensional graphite layer structures and/or three-dimensional graphite microcrystals.
3. The activated carbon sound absorbing material of claim 2, wherein the amorphous activated carbon particles are one or more of spherical, spheroidal, platelet, and rod shaped.
4. The activated carbon sound absorbing material of claim 3, wherein the amorphous activated carbon particles have a particle size ranging from 0.1 to 100 μm.
5. The activated carbon sound absorbing material of claim 2, wherein the amorphous activated carbon particles comprise hydrophobic amorphous activated carbon particles.
6. The activated carbon sound-absorbing material according to claim 1, wherein the activated carbon sound-absorbing material is configured to have an adsorption amount of nitrogen gas of 0.05mmol/g or more.
7. The activated carbon sound absorbing material of claim 1, wherein the nano-scale pore channel structure comprises micropores and mesopores, the pore diameter of the micropores is in a range of 0.5 nm to 2nm, and the pore diameter of the mesopores is in a range of 2nm to 20 nm.
8. The activated carbon sound absorbing material of claim 7, wherein the pores have a pore size ranging from 0.7 to 1.3nm, and the pores have a pore size ranging from 2 to 3.5 nm.
9. A sound generating device, comprising:
a housing having an accommodating chamber formed therein;
a vibration assembly disposed in the housing;
the active carbon sound absorption material as set forth in any one of claims 1 to 8 is disposed in the accommodation chamber.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811447854.9A CN109448688B (en) | 2018-11-29 | 2018-11-29 | Active carbon sound-absorbing material and sound-producing device |
| PCT/CN2019/115988 WO2020108256A1 (en) | 2018-11-29 | 2019-11-06 | Amorphous activated carbon particles and sound-absorption particles and sound production device |
| PCT/CN2019/121810 WO2020108584A1 (en) | 2018-11-29 | 2019-11-29 | Activated carbon sound absorption material and sound generating apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811447854.9A CN109448688B (en) | 2018-11-29 | 2018-11-29 | Active carbon sound-absorbing material and sound-producing device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109448688A CN109448688A (en) | 2019-03-08 |
| CN109448688B true CN109448688B (en) | 2022-04-05 |
Family
ID=65555959
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811447854.9A Active CN109448688B (en) | 2018-11-29 | 2018-11-29 | Active carbon sound-absorbing material and sound-producing device |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN109448688B (en) |
| WO (2) | WO2020108256A1 (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109448688B (en) * | 2018-11-29 | 2022-04-05 | 歌尔股份有限公司 | Active carbon sound-absorbing material and sound-producing device |
| CN110012383A (en) * | 2019-03-14 | 2019-07-12 | 歌尔股份有限公司 | For reducing the active carbon sound-absorbing particle and sounding device of sounding device resonance frequency |
| CN110047459A (en) * | 2019-03-14 | 2019-07-23 | 歌尔股份有限公司 | For reducing the active carbon sound-absorbing material and sounding device of sounding device resonance frequency |
| CN109935224A (en) * | 2019-03-14 | 2019-06-25 | 歌尔股份有限公司 | For reducing the active carbon sound-absorbing material and sounding device of sounding device resonance frequency |
| CN109963243A (en) * | 2019-03-14 | 2019-07-02 | 歌尔股份有限公司 | For reducing the active carbon sound-absorbing particle and sounding device of sounding device resonance frequency |
| CN109922414A (en) * | 2019-03-14 | 2019-06-21 | 歌尔股份有限公司 | For reducing the active carbon sound-absorbing material and sounding device of sounding device resonance frequency |
| CN110817863A (en) * | 2019-12-09 | 2020-02-21 | 歌尔股份有限公司 | Activated carbon sound-absorbing particle and sound-producing device |
| CN110980733B (en) * | 2019-12-09 | 2022-01-07 | 歌尔股份有限公司 | Activated carbon sound-absorbing particle and sound-producing device |
| CN111179897A (en) * | 2020-01-02 | 2020-05-19 | 歌尔股份有限公司 | Active carbon sound absorbing material, sound generating device and electronic equipment |
| CN111135772A (en) * | 2020-01-02 | 2020-05-12 | 歌尔股份有限公司 | Sound absorbing material preparation method, sound absorbing material, sound generating device and electronic equipment |
| CN111163395B (en) * | 2020-01-02 | 2022-01-07 | 歌尔股份有限公司 | Sound-absorbing particle, sound-generating device, and electronic apparatus |
| CN111182419B (en) * | 2020-01-02 | 2022-01-07 | 歌尔股份有限公司 | Sound-absorbing particle, sound-generating device, and electronic apparatus |
| CN111147987B (en) * | 2020-01-02 | 2022-01-07 | 歌尔股份有限公司 | Sound-absorbing particle, sound-generating device, and electronic apparatus |
| CN111163403B (en) * | 2020-01-02 | 2022-01-07 | 歌尔股份有限公司 | Sound-absorbing particle, sound-generating device, and electronic apparatus |
| CN116097346A (en) * | 2020-09-11 | 2023-05-09 | 3M创新有限公司 | Sound absorbing filler and related acoustic article |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009280986A (en) * | 2008-05-20 | 2009-12-03 | Sagaken Chiiki Sangyo Shien Center | Sound absorbing plate and its method for manufacturing |
| CN102089802A (en) * | 2008-10-02 | 2011-06-08 | 名古屋油化株式会社 | Sound absorbing material, multilayer sound absorbing material, molded product of multilayer sound absorbing material, sound absorbing interior material, and sound absorbing floor covering material |
| CN104583120A (en) * | 2012-07-26 | 2015-04-29 | 关西热化学株式会社 | Activated carbon having large active surface area |
| CN105516880A (en) * | 2015-12-01 | 2016-04-20 | 歌尔声学股份有限公司 | Sound absorbing material preparation method, sound absorbing material and loudspeaker |
| CN107046665A (en) * | 2017-03-30 | 2017-08-15 | 歌尔股份有限公司 | Composite ceramics sound-absorbing part and sound-producing device module |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60149093A (en) * | 1984-01-14 | 1985-08-06 | 住友電気工業株式会社 | Underwater sound absorbing material |
| WO2005068537A1 (en) * | 2004-01-15 | 2005-07-28 | Matsushita Electric Industrial Co., Ltd. | Porous body and method for producing same |
| DE102011107693A1 (en) * | 2011-07-13 | 2013-01-17 | Otto Bock Schaumsysteme Gmbh | Increasing the sound absorption in insulating materials |
| CN203859791U (en) * | 2014-04-29 | 2014-10-01 | 深圳市渴望通信有限公司 | Novel mobile phone with loudspeaker |
| CN105101036B (en) * | 2015-07-31 | 2018-08-14 | 瑞声光电科技(常州)有限公司 | Microphone device |
| CN105237033B (en) * | 2015-09-06 | 2018-11-30 | 歌尔股份有限公司 | Sound-absorbing material preparation method, sound-absorbing material and its fill method |
| CN105195061B (en) * | 2015-09-06 | 2018-04-13 | 歌尔股份有限公司 | Sound-absorbing material preparation method and sound-absorbing material |
| CN109448688B (en) * | 2018-11-29 | 2022-04-05 | 歌尔股份有限公司 | Active carbon sound-absorbing material and sound-producing device |
| CN109511056B (en) * | 2018-11-29 | 2021-05-18 | 歌尔股份有限公司 | Amorphous activated carbon particle, sound-absorbing particle and sound-producing device |
| CN109511058B (en) * | 2018-11-29 | 2021-05-18 | 歌尔股份有限公司 | Amorphous activated carbon particle, sound-absorbing particle and sound-producing device |
| CN109640237B (en) * | 2018-11-29 | 2021-05-18 | 歌尔股份有限公司 | Active carbon sound-absorbing material and sound-producing device |
| CN109511057B (en) * | 2018-11-29 | 2021-05-18 | 歌尔股份有限公司 | Amorphous activated carbon particle, sound-absorbing particle and sound-producing device |
| CN109660924B (en) * | 2018-11-29 | 2021-05-18 | 歌尔股份有限公司 | Activated carbon sound-absorbing particle and sound production device |
-
2018
- 2018-11-29 CN CN201811447854.9A patent/CN109448688B/en active Active
-
2019
- 2019-11-06 WO PCT/CN2019/115988 patent/WO2020108256A1/en active Application Filing
- 2019-11-29 WO PCT/CN2019/121810 patent/WO2020108584A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009280986A (en) * | 2008-05-20 | 2009-12-03 | Sagaken Chiiki Sangyo Shien Center | Sound absorbing plate and its method for manufacturing |
| CN102089802A (en) * | 2008-10-02 | 2011-06-08 | 名古屋油化株式会社 | Sound absorbing material, multilayer sound absorbing material, molded product of multilayer sound absorbing material, sound absorbing interior material, and sound absorbing floor covering material |
| CN104583120A (en) * | 2012-07-26 | 2015-04-29 | 关西热化学株式会社 | Activated carbon having large active surface area |
| CN105516880A (en) * | 2015-12-01 | 2016-04-20 | 歌尔声学股份有限公司 | Sound absorbing material preparation method, sound absorbing material and loudspeaker |
| CN107046665A (en) * | 2017-03-30 | 2017-08-15 | 歌尔股份有限公司 | Composite ceramics sound-absorbing part and sound-producing device module |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2020108256A1 (en) | 2020-06-04 |
| WO2020108584A1 (en) | 2020-06-04 |
| CN109448688A (en) | 2019-03-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109448688B (en) | Active carbon sound-absorbing material and sound-producing device | |
| CN109660924B (en) | Activated carbon sound-absorbing particle and sound production device | |
| CN109511057B (en) | Amorphous activated carbon particle, sound-absorbing particle and sound-producing device | |
| CN109511056B (en) | Amorphous activated carbon particle, sound-absorbing particle and sound-producing device | |
| CN109511058B (en) | Amorphous activated carbon particle, sound-absorbing particle and sound-producing device | |
| CN109640237B (en) | Active carbon sound-absorbing material and sound-producing device | |
| CN111163395B (en) | Sound-absorbing particle, sound-generating device, and electronic apparatus | |
| CN111147987B (en) | Sound-absorbing particle, sound-generating device, and electronic apparatus | |
| CN111163403B (en) | Sound-absorbing particle, sound-generating device, and electronic apparatus | |
| CN111182419B (en) | Sound-absorbing particle, sound-generating device, and electronic apparatus | |
| CN111135772A (en) | Sound absorbing material preparation method, sound absorbing material, sound generating device and electronic equipment | |
| CN111179897A (en) | Active carbon sound absorbing material, sound generating device and electronic equipment | |
| WO2021115280A1 (en) | Activated carbon sound-absorbing granules and sound-producing device | |
| CN109874089B (en) | Silica aerogel sound absorbing material and sound generating device | |
| WO2018176664A1 (en) | Metal-organic framework sound absorbing member and sound producing device module | |
| CN109935224A (en) | For reducing the active carbon sound-absorbing material and sounding device of sounding device resonance frequency | |
| CN110980733B (en) | Activated carbon sound-absorbing particle and sound-producing device | |
| CN109963243A (en) | For reducing the active carbon sound-absorbing particle and sounding device of sounding device resonance frequency | |
| CN110012383A (en) | For reducing the active carbon sound-absorbing particle and sounding device of sounding device resonance frequency | |
| CN109678392B (en) | Silica aerogel sound absorbing material and sound generating device | |
| CN109922414A (en) | For reducing the active carbon sound-absorbing material and sounding device of sounding device resonance frequency | |
| CN110047459A (en) | For reducing the active carbon sound-absorbing material and sounding device of sounding device resonance frequency | |
| CN116959395A (en) | Sound absorbing material, sound generating device and electronic equipment | |
| CN116847254A (en) | Sound absorbing material, sound generating device and electronic equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |