WO2020107618A1 - Sound producing device - Google Patents

Abstract

A sound producing device comprises: a magnetic circuit system (19) configured to form a magnetic field; and a vibration system comprising a voice coil (16), a diaphragm (11), and a reinforcement layer (15). One end of the voice coil (16) is connected to a center portion of the diaphragm (11), and the other end is located in a magnetic field. The reinforcement layer (15) is disposed in the center portion, and comprises a carbon fiber prepreg layer (26). The diameter of carbon fibers in the carbon fiber prepreg layer (26) is less than or equal to 7 μm. The carbon fibers located in the same layer are unidirectional and disposed side by side.

Description

Sounding device Technical field

The present invention relates to the technical field of electroacoustic conversion, and more specifically, to a sound emitting device.

Background technique

The speaker unit sounds through the vibration system. The vibration system includes a diaphragm, voice coil and reinforcement layer. The reinforcement layer is usually made of plastic or metal. The low elastic modulus of these two materials leads to the deformation of the reinforcement layer at high frequencies. The inconsistency of the vibrations of the various parts of the reinforcement layer will cause noise in the speaker unit, greatly reducing the listening effect.

Therefore, it is necessary to provide a new technical solution to solve the above technical problems.

Summary of the invention

An object of the present invention is to provide a new technical solution for a sounding device.

According to the first aspect of the present invention, a sound generating device is provided. The device includes: a magnetic circuit system configured to form a magnetic field; and a vibration system including a voice coil, a diaphragm, and a reinforcement layer, one end of the voice coil and the vibration The central part of the membrane is connected, and the other end is located in the magnetic field. The reinforcing layer is provided in the central part. The reinforcing layer includes a carbon fiber prepreg layer. The diameter is less than or equal to 7μm, and the carbon fibers in the same layer are unidirectional and arranged side by side.

Optionally, the carbon content of the carbon fiber in the carbon fiber prepreg layer is greater than or equal to 94%.

Optionally, the specific modulus of carbon fibers in the carbon fiber prepreg layer is greater than or equal to 163 GPa·cm ³ /g.

Optionally, the carbon fiber in the carbon fiber prepreg layer is a single layer or multiple layers.

Optionally, the reinforcing layer includes a foam core layer and two carbon fiber prepreg layers connected to the upper and lower surfaces of the foam core layer.

Optionally, the foam core layer is PMI foam material, PI foam material or polyester foam material.

Optionally, the resin of the carbon fiber prepreg layer is epoxy resin, phenol resin, bismaleimide resin, polyimide value or vinyl resin.

Optionally, the diaphragm and the reinforcing layer constitute a vibration plate, and the thickness of the vibration plate is less than or equal to 3 mm.

Optionally, the reinforcing layer is rectangular, and the reinforcing layer includes a first side and a second side, and a length ratio of the first side to the second side is 1:1-4:1.

Optionally, the reinforcing layer is rectangular, the reinforcing layer includes a first side and a second side, the length of the first side is 9.1mm-15.2mm, and the length of the second side is 6.1mm -11.2mm.

According to an embodiment of the present disclosure, the sound-generating device has characteristics of excellent high-frequency performance.

Other features and advantages of the present invention will become clear by the following detailed description of exemplary embodiments of the present invention with reference to the drawings.

BRIEF DESCRIPTION

The drawings incorporated in and forming a part of the specification illustrate embodiments of the present invention, and together with the description serve to explain the principles of the present invention.

FIG. 1 is a cross-sectional view of a sound emitting device according to an embodiment of the present disclosure.

FIG. 2 is a schematic structural diagram of a reinforcement layer according to an embodiment of the present disclosure.

FIG. 3 is a front view of a reinforcement layer according to an embodiment of the present disclosure.

Fig. 4 is a schematic diagram of the orientation of graphite crystallites along the fiber axis.

FIG. 5 is a schematic diagram of graphite crystallites oriented at a set angle with the fiber axis.

FIG. 6 is a comparison diagram of sound pressure levels of the sound emitting device of the embodiment of the present disclosure and the existing sound emitting device.

FIG. 7 is a comparison diagram of the THD of the sound emitting device of the embodiment of the present disclosure and the existing sound emitting device.

FIG. 8 is a R&B comparison diagram of the sound generating device of the embodiment of the present disclosure and the existing sound generating device.

9-10 are cross-sectional views of a reinforcement layer according to an embodiment of the present disclosure

Description of reference signs:

11: diaphragm; 13: edge portion; 14: folded ring portion; 15: reinforcement layer; 16: voice coil; 17: centering piece; 18: magnetic gap; 19: magnetic circuit system; 20: carbon fiber; 21 : Prepreg resin; 22: shell; 23: first side; 24: second side; 25: graphite crystallite; 26: carbon fiber prepreg layer; 27: foam core layer; 28: outer cover layer.

detailed description

Various exemplary embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of components and steps, 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 actually merely illustrative, and in no way serves as any limitation on the invention and its application or use.

Techniques, methods and equipment known to those of ordinary skill in the related art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the specification.

In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiment may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, so once an item is defined in one drawing, there is no need to discuss it further in subsequent drawings.

According to an embodiment of the present disclosure, a sound emitting device is provided. As shown in FIG. 1, the sound generating device includes a magnetic circuit system 19 and a vibration system. The magnetic circuit system 19 is configured to form a magnetic field. For example, the magnetic circuit system 19 includes permanent magnets. The permanent magnet forms a magnetic field in the magnetic gap 18. The magnetic circuit system 19 is common knowledge in the art and will not be described in detail here.

The vibration system includes a voice coil 16, a diaphragm 11, and a reinforcement layer 15. One end of the voice coil 16 is connected to the central portion of the diaphragm 11, and the other end is located in the magnetic field. The reinforcement layer 15 is provided at the center. The reinforcing layer 15 includes a carbon fiber prepreg layer 26. The orientation angle of the carbon fiber 20 in the carbon fiber prepreg layer 26 is less than or equal to 30°. Carbon fiber is made of numerous graphite crystallites 25 stacked and oriented. As shown in Figure 4-5, the orientation angle is the angle between the graphite crystallite 25 and the fiber axis, as shown in Figure 5

As shown. The graphite crystallite 25 has a sheet-like structure. The fiber axis is the extension axis of the carbon fiber 20 in the main direction, as shown by the arrow A in FIGS. 4-5.

The elastic modulus of the carbon fiber 20 is calculated by the following formula:

As shown in Fig. 4, when graphite crystallites 25 are parallel to the fiber axis, the orientation angle

Is 0, at this time, the elastic modulus is:

As shown in Fig. 5, when graphite crystallites 25 are not parallel to the fiber axis, the orientation angle

Not 0, at this time, the elastic modulus is:

Where Fz is the axial tensile force, Sz is the projected area of the graphite crystallites in the fiber axis, and ε _z is the strain of the graphite crystallites in the fiber axial direction,

Is the angle between the graphite microchip layer and the fiber axis, Lc is: the stacking thickness of the graphite microcrystal 25, La _Ⅱ is the width of the base surface of the graphite microcrystal 25 parallel to the fiber axis, and E ₀ is the direction of the graphite microchip layer The theoretical modulus, E1 is the normal tensile modulus of the graphite sheet, and _{La a⊥} is the width of the base surface of the graphite crystallite 25 perpendicular to the fiber axis.

The shape factor is the ratio of the stacking thickness of graphite crystallites 25 to the width of the base surface of graphite crystallites 25, ie

When the shape factor is constant, the elastic modulus decreases as the orientation angle increases.

When the orientation angle is ≦30°, the elastic modulus of the carbon fiber 20 is large, and the rigidity of the carbon fiber prepreg layer 26 is large, and the effect of improving the high-frequency acoustic performance of the sound generating device is good.

In addition, during long-term use, the reinforcing layer 15 still maintains good rigidity. The reliability of the sounding device is good.

When the orientation angle is greater than 30°, the elastic modulus of the carbon fiber 20 is greatly lost. The elastic modulus of the carbon fiber 20 is relatively small, and the improvement of the high-frequency acoustic performance of the sound-generating device is small. The reliability of the sounding device is reduced.

When the orientation angle is fixed, the elastic modulus decreases with the increase of the shape factor. Preferably, when the shape factor of the carbon fiber 20 is 0.1-1.5, the elastic modulus and tensile strength of the carbon fiber 20 are greater than those of the carbon fiber 20 outside this range. The carbon fiber prepreg layer 26 has a high rigidity.

In one example, the diaphragm 11 includes a center portion located at the center, an edge portion 13 located at the edge, and a folded ring portion 14 located between the center portion and the edge portion 13. It may be that the diaphragm 11 has a planar structure. An annular housing 22 is provided on the magnetic circuit system 19. The edge portion 13 is adhered to the case 22 by glue. The reinforcing layer 15 is adhered to the center by an adhesive or double-sided tape. The reinforcing layer 15 and the voice coil 16 are located on the upper and lower sides of the diaphragm 11, respectively.

For example, the diaphragm 11 is made of one or more materials selected from engineering plastics, elastomer materials, and adhesive films. For example, engineering plastics include PEEK, PAR, etc. Elastomer materials include TPU, TPEE, silicone rubber, etc. The adhesive film includes an acrylic adhesive film, a silicone adhesive film, and the like.

For example, the thickness of the diaphragm 11 is 0.01 mm-0.5 mm. The diaphragm 11 in this range has good elasticity and high strength.

In one example, a centering support piece 17 is provided between the voice coil 16 and the diaphragm 11. The voice coil 16 communicates with external equipment through the centering support 17. The centering piece 17 can effectively prevent polarization of the vibration system.

In one example, the carbon content of the carbon fiber 20 in the carbon fiber prepreg layer 26 is less than or equal to 6%. The lower the nitrogen content of the carbon fiber 20, the higher the carbon content. The smaller the proportion of nitrogen atoms as heteroatoms in the carbon fiber 20 and the smaller the damage to the crystal phase structure of the carbon fiber 20, the higher the elastic modulus of the carbon fiber 20.

For example, polyacrylonitrile fiber, pitch fiber, viscose fiber or phenolic fiber is subjected to high-temperature carbonization treatment to obtain carbon fiber 20. The carbonization treatment can reduce the nitrogen content in the carbon fiber 20 and increase the carbon content to enhance the graphite crystallite orientation.

Further, the carbon content of the carbon fiber 20 in the carbon fiber prepreg layer 26 is greater than or equal to 94%. The higher the carbon content, the fewer impurity atoms in the carbon fiber 20 and the higher the elastic modulus. The reinforcing layer 15 within this range has the characteristics of high rigidity.

In one example, the carbon fiber 20 in the carbon fiber prepreg layer 26 is a single layer or multiple layers. The carbon fibers 20 located in the same layer are unidirectional and arranged side by side.

For example, as shown in FIGS. 2-3, a plurality of carbon fibers 20 are arranged parallel to each other in a layer. Then, the prepreg resin 21 is applied to the carbon fiber 20 by means of a coating film to form a carbon fiber prepreg. After curing, the carbon fiber prepreg forms a single layer of carbon fiber prepreg 26. For example, curing by hot pressing. The prepreg resin 21 may be, but not limited to, epoxy resin, phenol resin, bismaleimide resin, polyimide resin, vinyl resin, and the like.

For example, the above-mentioned single-layer carbon fiber prepreg layers 26 are stacked to form a multi-layer prepreg. The multilayer prepreg forms a multilayer carbon fiber prepreg layer 26 after curing. The carbon fibers 20 in each layer are arranged in the same direction.

The single-layer or multi-layer carbon fiber prepreg layer 26 has the characteristics of high elastic modulus and high tensile strength in a set direction.

In addition, when the carbon fiber prepreg layer 26 is used as the surface layer of the reinforcing layer, unidirectional, side-by-side carbon fibers form a groove structure on the surface layer. When vibrating, the groove structure can effectively comb the airflow, which reduces the noise component of the airflow and improves the sound purity of the sounding device.

In one example, the carbonization temperature of the carbon fiber 20 is 1700° C. or higher. At this temperature, the orientation shape of the graphite crystallite 25 is better, and the orientation angle is within 30°, even close to 0°. The arrangement of graphite crystallites 25 is more regular. The elastic modulus and tensile strength of the carbon fiber 20 are significantly higher than the carbon fiber 20 obtained below the carbonization temperature.

In addition, in the temperature range, the diameter of the fiber filament of the carbon fiber 20 is small. For example, the diameter can reach 7 μm or less. The smaller the diameter of the carbon fiber 20, the higher the tensile strength and elastic modulus. The carbon fiber 20 in this diameter range can meet the rigidity requirement of the sound-generating device for the reinforcing layer 15.

In addition, this enables the carbon fiber prepreg layer 26 of the same thickness to have more layers of the carbon fiber 20, which further increases the rigidity of the carbon fiber prepreg layer 26.

In the sound-generating device, generally, the rigidity in the set direction is improved so that the sound-generating device has good high-frequency performance. In this example, the carbon fiber 20 extends in a set direction, and the carbon fiber 20 has a high tensile strength in the set direction, so that the carbon fiber prepreg layer 26 has a greater stiffness in the set direction, which can improve sound generation The high-frequency performance of the device can also save the amount of carbon fiber 20.

In one example, the specific modulus of the carbon fiber 20 in the carbon fiber prepreg layer 26 is greater than or equal to 163 GPa·cm ³ /g. The specific modulus is the ratio of the elastic modulus of the material to the density. The greater the specific modulus, the greater the elastic modulus and/or the lower the density of the material. Within this specific modulus range, the stiffness of the reinforcing layer 15 is high, and the high-frequency performance of the sound-generating device is significantly improved.

In one example, as shown in FIG. 9, the reinforcing layer 15 includes a foam core layer 27 and two carbon fiber prepreg layers 26 connected to the upper and lower surfaces of the foam core layer 27. The reinforcing layer 15 has a "sandwich" structure. The foam core layer 27 has a characteristic of low density. The high-frequency performance of the sound-generating device is positively correlated with the thickness of the reinforcing layer 15, that is, it increases as the thickness increases, and decreases as the thickness decreases. The high-frequency performance of the sound-generating device is inversely related to the density of the reinforcing layer 15, that is, it decreases as the density increases and increases as the density decreases. The foam core layer 27 can reduce the overall density of the reinforcing layer 15 and increase the overall thickness of the reinforcing layer 15, thereby significantly improving the high-frequency performance of the sound generating device. Preferably, the thickness of the reinforcing layer 15 is 0.02mm-1mm. Within this range, the stiffness of the reinforcing layer 15 is high, and the thickness of the sounding device is not increased additionally.

Further, the thickness of the reinforcing layer 15 is 0.02 mm-0.5 mm.

In addition, the multiple carbon fiber prepreg layers 26 significantly increase the elastic modulus of the reinforcing layer 15.

The foam core layer 27 may be, but is not limited to, foam material. The foam material has pores inside. For example, foam materials include PMI foam materials, PI foam materials, polyester foam materials, and the like.

Preferably, the thickness of the foam core layer 27 is 0.05 mm-1 mm. Within this thickness range, the reinforcing layer 15 has good rigidity, and does not increase the overall thickness of the sound emitting device additionally.

In one example, the carbon fiber prepreg layer 26 has a multilayer structure. The reinforcing layer 15 includes a carbon fiber prepreg layer 26 and a foam core layer 27 compounded together. The stiffness of the reinforcing layer 15 is greater and the overall density is smaller, which can more effectively improve the high-frequency effect of the sound-generating device.

Preferably, a foam core layer 27 is provided between the two carbon fiber prepreg layers 26. The stiffness of this reinforcing layer 15 is greater.

The greater the number of carbon fiber 20 layers, the greater the elastic modulus of the carbon fiber prepreg layer 26, but the density will also increase accordingly. When the number of layers is within the set range, the increase in elastic modulus is greater than the increase in density, and the specific modulus increases with the increase in layers; when the number of layers exceeds the set value, the increase in elastic modulus is less than the increase in density The amplitude and specific modulus will decrease as the number of layers increases. For example, the number of carbon fibers 20 in the carbon fiber prepreg layer 26 is less than or equal to 16. Within this range, the specific modulus of the carbon fiber prepreg layer 26 increases as the number of layers increases, so that the high-frequency effect of the sound generating device can be significantly improved.

In one example, as shown in FIG. 10, the reinforcing layer 15 further includes outer layers 28 respectively bonded to at least one surface of the carbon fiber prepreg layer 26 away from the foam core layer 27. In this example, the outer layer 28 serves as the surface layer of the reinforcing layer 15. The outer layer 28 is a sealing material, and gas and water cannot penetrate the outer layer 28. The provision of the outer cover layer 28 can significantly improve the airtightness and waterproof level of the reinforcing layer 15.

For example, the outer cover 28 is at least one of engineering plastic, aluminum, and damping material. Damping materials include: damping glue, rubber, etc. For example, the damping glue is acrylic glue. The above materials have the characteristics of high hardness and low density, and can significantly improve the structural strength of the reinforcing layer 15.

In one example, the reinforcement layer 15 is prepared by hot-press co-curing. For example, when the reinforcing layer 15 includes only the carbon fiber prepreg, the material after the coating film is placed in a hot press, and hot pressing is performed at a set temperature. After the prepreg resin 21 is cured, the reinforcing layer 15 is formed.

When the reinforcing layer 15 has a multilayer structure, for example, the reinforcing layer 15 has the above-mentioned "sandwich" structure or the above-mentioned structure including the outer cover layer 28. First, the layers are stacked together in a predetermined order. Then, it is placed in a hot press and hot pressed at a set temperature. After curing, the prepreg resin 21 can form a bonding force with the outer layer 28 and the foam core layer 27.

In other examples, the carbon fiber prepreg layer 26 is cut from a roll of carbon fiber 20 with a release film. The carbon fiber 20 coil itself is a cured carbon fiber prepreg. During production, the carbon fiber 20 coil is cut according to the set shape to remove the release film, and then hot-press co-cured with other materials or multiple layers of carbon fiber prepreg layer 26 for molding. Under heating conditions, the prepreg resin 21 of the carbon fiber prepreg regains viscosity and can be compounded with other materials or other carbon fiber prepregs.

In one example, the reinforcement layer 15 has a rectangular shape. As shown in FIGS. 2-3, the reinforcing layer 15 includes a first side 23 and a second side 24. The length of the first side 23 is greater than or equal to the length of the second side 24. The larger the area of the reinforcing layer 15 is, the easier the division vibration occurs, and the smaller the size, the smaller the size of the sounding device. For example, the length of the first side 23 is 9.1 mm-15.2 mm. The length of the second side 24 is 6.1 mm-11.2 mm. Within this range, the split vibration of the reinforcing layer 15 is small.

The longer the length of the reinforcing layer 15 in one direction, the uneven vibration of the reinforcing layer 15 is likely to occur in that direction, thereby causing noise to occur in the sound emitting device. For example, the length ratio of the first side 23 to the second side 24 is 1:1-4:1. Within this range, the vibration of each part of the reinforcement layer 15 is more balanced, and the noise of the sound generating device is small.

The angle between the main direction of the carbon fiber 20 of the carbon fiber prepreg layer 26 and the first side 23 is 45-90°, as shown in B in FIG. 3. The main direction of the carbon fiber 20 refers to the direction of the fiber filament. Under normal circumstances, the diaphragm 11 and the reinforcing layer 15 constitute a diaphragm. At high frequencies, the split vibration in the direction perpendicular to the first side 23 is large, so the increase in rigidity perpendicular to the direction of the first side 23 has an important influence on the improvement of the high-frequency performance of the sound generating device. The reinforcing layer 15 formed by the carbon fibers 20 within the included angle range has a relatively high rigidity in the direction perpendicular to the first side 23, which significantly improves the high-frequency performance of the sound generating device.

Preferably, the main direction of the carbon fibers 20 of the carbon fiber prepreg layer 26 is perpendicular to the first side 23, as shown in FIG. 3. In this arrangement, the tensile strength of the reinforcing layer 15 in this direction is higher, and the high-frequency performance of the sound generating device is excellent.

Example 1:

In this example, the performance of carbon fibers 20 of different diameters of the same material is tested. As the carbon fiber 20, polyacrylonitrile-based carbon fiber or pitch-based carbon fiber is used. See Table 1 for details.

Original silk diameter/μm		Carbon fiber 20 diameter/μm	Tensile strength/GPa	Modulus of elasticity/GPa
6	3.1	5.89	286
7	3.6	5.45	281
8	5.0	4.46	274
11	7.0	3.79	259
13	8.5	3.46	251

Table 1-The relationship between the diameter of the raw silk, the diameter of the carbon fiber 20 and the mechanical properties of the carbon fiber 20

It can be seen from Table 1 that as the diameter of the carbon fiber 20 decreases, the tensile strength and elastic modulus of the carbon fiber 20 gradually increase. When the diameter of the carbon fiber 20 is 7.0 μm or less, the tensile strength and elastic modulus of the carbon fiber 20 are large, reaching 3.79 GPa and 259 GPa, respectively. The stiffness of the carbon fiber prepreg layer 26 of the reinforcing layer 15 in this range is large, and the high-frequency performance of the sound generating device is significantly improved.

Example 2:

In this example, the diameters and mechanical properties of carbon fibers 20 of different brands and different diameters are compared. See Table 2 for details.

Grade	diameter	tensile strength	Elastic Modulus
T-300	7.0	3.53	230
T-800H	5.2	5.59	294
T-1000	5.3	7.06	294
LM-400	6.4	4.51	294
LM-500	5.0	5.10	300
LM-600	5.0	5.79	285
MR50P	5.0	5.49	294

MR60P	5.0	6.17	294
MRE60P	5.0	6.17	323

Table 2-The main mechanical properties of different grades of carbon fiber 20

It can be seen from Table 2 that the diameters of the above-mentioned various carbon fibers 20 are within 7.0 μm, and all have high tensile strength and elastic modulus, which makes the stiffness of the reinforcing layer 15 significantly increase.

Example 3:

The acoustic performance of the sound generating device of the embodiment of the present invention is compared with the existing sound generating device. Among them, the power of the two sounding devices is the same. The reinforcing layer 15 of the sound emitting device of the embodiment of the present invention has a structure of a unidirectional carbon fiber prepreg layer+PMI foam core layer+unidirectional carbon fiber prepreg layer. The unidirectional carbon fiber prepreg layer is provided with a layer of carbon fiber. The diameter of the carbon fiber is 4-5 μm, and the arrangement direction is the same; the material of the reinforcement layer 15 of the existing sound emitting device is aluminum foil + film + PMI foam core + film + aluminum foil. The two reinforcing layers 15 have the same size, and the length of the sounding device is 18 mm, and the width is 13 mm. The length of the reinforcing layer 15 is 14 mm, and the width is 9 mm.

FIG. 6 is a comparison diagram of sound pressure levels of the sound emitting device of the embodiment of the present disclosure and the existing sound emitting device. Among them, the abscissa is the frequency, and the ordinate is the sound pressure level.

FIG. 7 is a comparison diagram of the THD of the sound emitting device of the embodiment of the present disclosure and the existing sound emitting device. Among them, the abscissa is frequency, and the ordinate is THD.

FIG. 8 is a R&B comparison diagram of the sound generating device of the embodiment of the present disclosure and the existing sound generating device. Among them, the abscissa is frequency, and the ordinate is R&B.

In FIG. 6, the dotted line c1 represents the test curve of the sound emitting device of the embodiment of the present invention; the solid line c2 is the test curve of the existing sound emitting device. It can be seen from FIG. 6 that at high frequency bands, for example, frequencies above 6000 Hz, the c1 curve is located above the c2 curve. This shows that the sound-generating device of the embodiment of the present invention has more excellent high-frequency performance.

In FIG. 7, the dashed line d1 represents the test curve of the sound emitting device of the embodiment of the present invention; the solid line d2 is the test curve of the existing sound emitting device. It can be seen from FIG. 7 that the sound pressure level of the existing sound-generating device is significantly increased near 6000 Hz, and a peak appears. However, the sound pressure level of the sound emitting device of the embodiment of the present invention at around 6000 Hz is significantly lower than that of the existing sound emitting device, and the d1 curve has no sharp peaks at around 6000 Hz. This is because the reinforcing layer 15 of the embodiment of the present invention has high rigidity, and the vibration of each part of the reinforcing layer 15 can be ensured near this frequency, and the division vibration is effectively suppressed, making the noise component small. However, in the existing sound-generating device, the stiffness of the reinforcement layer 15 is insufficient, and the vibration is uneven at this frequency, and the noise component is large, thereby forming a peak.

Therefore, the sound-generating device of the present invention has a more excellent listening effect, especially in the high frequency band.

In addition, in other examples, due to the high stiffness of the reinforcement layer 15 of the sound emitting device of the embodiment of the present invention, this causes the high frequency peak in the THD curve to move significantly to the right, that is, to the high frequency direction, thereby making There will be no spikes in the frequency range, so that the high-frequency performance of the sounding device is improved.

In FIG. 8, the dotted line e1 represents the test curve of the sound emitting device of the embodiment of the present invention; the solid line e2 is the test curve of the existing sound emitting device. The reinforcing layer 15 of the sound emitting device of the present invention has a structure of a unidirectional carbon fiber prepreg layer+PMI foam core layer+unidirectional carbon fiber prepreg layer. The unidirectional carbon fiber prepreg layer is provided with a layer of carbon fiber. The diameter of the carbon fiber is 4-5 μm, and the arrangement direction is the same. Among them, the carbon fiber prepreg layer 26 serves as a surface layer of the reinforcing layer 15 near the sound emitting side. The carbon fibers 20 are arranged unidirectionally. The main direction of the carbon fiber 20 is perpendicular to the first side 23. The surface layer forms a uniform groove structure. The reinforcing layer 15 of the existing sound-emitting device is aluminum foil + adhesive film + PMI foam core layer + adhesive film + aluminum foil, and the surface layer of the reinforcing layer 15 has a planar structure.

As can be seen from FIG. 8, the R&B curve e1 of the sound emitting device of the embodiment of the present invention is significantly lower than the R&B curve e2 of the existing sound emitting device when it is near fo (for example, 800 Hz). The sound-generating device of the embodiment of the present invention has higher listening purity and smaller noise components. This is because the surface of the reinforcing layer 15 of the embodiment of the present invention forms a uniformly distributed groove structure, which plays a role in combing the airflow. When vibrating, the groove structure makes the noise component of the airflow smaller than the reinforcement layer 15 of the planar structure.

Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present invention. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present invention. The scope of the invention is defined by the appended claims.

Claims (10)

1. A sounding device, including:

   A magnetic circuit system configured to form a magnetic field; and

   Vibration system, the vibration system includes a voice coil, a diaphragm and a reinforcement layer, one end of the voice coil is connected to the central portion of the diaphragm, the other end is located in the magnetic field, the reinforcement layer is provided in In the central part, the reinforcing layer includes a carbon fiber prepreg layer. The diameter of the carbon fiber in the carbon fiber prepreg layer is less than or equal to 7 μm. The carbon fibers in the same layer are unidirectional and arranged side by side.
2. The sound generating device according to claim 1, wherein the carbon content of the carbon fiber in the carbon fiber prepreg layer is greater than or equal to 94%.
3. The sound generating device according to claim 1, wherein the specific modulus of the carbon fiber in the carbon fiber prepreg layer is greater than or equal to 163 GPa·cm ³ /g.
4. The sound generating device according to claim 1, wherein the carbon fiber in the carbon fiber prepreg layer is a single layer or multiple layers.
5. The sound generating device according to claim 4, wherein the reinforcing layer includes a foam core layer and two carbon fiber prepreg layers connected to upper and lower surfaces of the foam core layer.
6. The sound generating device according to claim 5, wherein the foam core layer is PMI foam material, PI foam material or polyester foam material.
7. The sound emitting device according to claim 1, wherein the resin of the carbon fiber prepreg layer is epoxy resin, phenol resin, bismaleimide resin, polyimide resin, or vinyl resin.
8. The sound generating device according to any one of claims 1 to 7, wherein the diaphragm and the reinforcing layer constitute a vibration plate, and the thickness of the vibration plate is less than or equal to 3 mm.
9. The sound generating device according to any one of claims 1-7, wherein the reinforcing layer is rectangular, and the reinforcing layer includes a first side and a second side, the first side and the second side The length ratio of the two sides is 1:1-4:1.
10. The sound generating device according to any one of claims 1-7, wherein the reinforcement layer is rectangular, the reinforcement layer includes a first side and a second side, and the length of the first side is 9.1 mm-15.2mm, the length of the second side is 6.1mm-11.2mm.

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