Acoustic reinforcement blocks and their applications, micro speakers and electronic devices

Abstract

The present invention provides an acoustic reinforcement block and its application, a micro speaker and an electronic device. The raw materials of the acoustic reinforcement block include a porous material, an adhesive and an auxiliary agent supported by a structural skeleton. The micro speaker includes an upper shell forming a cavity, a lower shell and a speaker unit located in the cavity, the cavity is divided into a front cavity and a back cavity, the front cavity communicates with the sound emission hole, and the upper shell is provided with a resonant cavity of the front cavity that communicates with the front cavity and is filled with an acoustic reinforcement material.

Description

[Technical Field]

[0001] The present invention relates to the field of speaker technology, in particular to acoustic reinforcement blocks and their applications, micro-speakers and electronic devices. [Background technology]

[0002] With the development of mobile phone terminal devices, users' requirements for mobile phone sound quality are becoming increasingly higher. In addition to the overall loudness, users' requirements for voice quality are also increasing day by day. The high-frequency performance, bandwidth, and non-flatness of a micro speaker have a significant impact on users' experience of music quality and detail.

[0003] Due to the presence of front cavity resonance and unit dome resonance, the high frequency response (FR) curve of the speaker tends to be uneven and the bandwidth tends to be narrow. To solve this problem, a method of adding a front cavity resonant cavity is often adopted. However, this method tends to increase the peak (Q value) and make the high frequency FR curve less than ideal.

[0004] Currently, there is only one technical means to improve the non-flatness and poor performance of the high frequency performance of micro speakers. For example, 1. It can be improved simply by adjusting the structural dimensions of the front cavity and sound outlet, but it is likely to be limited by the product's instant ID design. 2. Applying a corresponding audio algorithm to correct high frequencies, which is likely to cause "distortion" in the sound effects and lose the natural feel. 3. Adding a resonant cavity to the front cavity or adding a filter structure inside the resonant cavity of the front cavity increases the mold cost and limits the product to a quick ID design. Summary of the Invention

[0005] The present invention has been made to solve the above problems, and its purpose is to provide an acoustic reinforcement block and its application, as well as a micro-speaker and electronic device that can effectively improve the flatness of the high-frequency performance curve of a speaker by filling the resonant cavity of the front cavity with an acoustic reinforcement material, and that can also be manufactured using a simple process and with reduced mold difficulty.

[0006] In order to achieve the above-mentioned object, the present invention provides an acoustic reinforcement block in which the raw materials include a porous material, a skeletal material, an adhesive, and an auxiliary agent, the structural skeleton is made of a single layer of skeletal material or two or more layers of skeletal material stacked alternately, and the porous material, adhesive, and auxiliary agent are supported on the structural skeleton.

[0007] In the acoustic reinforcement block, the term "alternately laminated" refers to two or more single-layer skeleton materials arranged in layers along one direction.

[0008] In a specific embodiment of the present invention, the acoustic reinforcement block is a material that can improve the acoustic performance of a device such as a speaker, and generally can increase the acoustic virtual volume of the device such as a speaker and lower the minimum resonance frequency of the speaker device. In a specific embodiment of the present invention, the porous material, adhesive and auxiliary agent may be disposed on the surface of the scaffold and / or may infiltrate the internal voids of the scaffold in a single layer.

[0009] According to a specific embodiment of the present invention, the acoustical reinforcement block typically comprises 5-15% framework material, 2-10% adhesive, and 0.05-2% additive, with the remainder being porous material, where the total mass of the acoustical reinforcement block is 100%, where the mass content of the adhesive in the acoustical reinforcement block is calculated as the solid mass of the adhesive.

[0010] According to specific embodiments of the present invention, the acoustical reinforcement block may be a single block and / or a block formed by stacking two or more acoustical reinforcement blocks (typically thin layered blocks). In some embodiments, the acoustical reinforcement block may be produced by a baking, drying or freeze-drying method.

[0011] According to a specific embodiment of the present invention, the porous material may comprise one or a combination of two or more of zeolite, activated carbon, and MOF material.

[0012] According to a specific embodiment of the present invention, the zeolite generally has a Si (silicon) / M mass ratio of 200 or more, where M is generally a trivalent metal element, i.e., a metal element having a positive valence of 3, such as one or a combination of two or more of iron, aluminum, and titanium.

[0013] According to a specific embodiment of the present invention, the zeolite may include one or a combination of two or more of MFI molecular sieves, FER molecular sieves, CHA molecular sieves, IHW molecular sieves, IWV molecular sieves, ITE molecular sieves, UTL molecular sieves, VET molecular sieves, MEL molecular sieves, and MTW molecular sieves.

[0014] According to a specific embodiment of the present invention, the adhesive may include an organic adhesive and / or an inorganic adhesive.

[0015] According to a specific embodiment of the present invention, the organic adhesive may include one or a combination of two or more of polyacrylate suspension, polystyrene acetate suspension, polyvinyl acetate suspension, polyethylene vinyl acetate suspension, and polybutadiene rubber suspension.

[0016] According to a specific embodiment of the present invention, the inorganic adhesive may include one or a combination of two or more of silica sol, alumina sol, and pseudoboehmite (such as SB powder).

[0017] According to a specific embodiment of the present invention, the auxiliary may include one or a combination of two or more of CMC (carboxymethyl cellulose), montmorillonite, kaolin, attapulgite, and mica powder.

[0018] According to a specific embodiment of the present invention, the mechanical properties of the acoustic reinforcement block can be effectively improved by adding a framework material to form a structural framework, which is generally a fibrous material, and typically includes one or a combination of two or more of fiber paper, fiber cloth, and fiber felt.

[0019] According to a specific embodiment of the present invention, the framework material is generally composed of alternating layers of layered and / or corrugated fiber paper, fiber cloth, or fiber felt, and Fig. 1 shows how the layered and corrugated fiber materials are alternately stacked. In some specific embodiments, the flute height of the corrugated fiber paper, fiber cloth, or fiber felt is generally 0.2 mm-2 mm. According to a specific embodiment of the present invention, the framework material may include chemical fibers, and specifically, the framework material may be manufactured from chemical fibers by any of blending, bonding, or wet molding.

[0020] According to a specific embodiment of the present invention, the basis weight of the framework material is generally 10 g / m 2 -100 g / m 2 .

[0021] According to a specific embodiment of the present invention, the diameter of a single fiber in the chemical fiber is generally 2 μm-40 μm.

[0022] According to specific embodiments of the present invention, the chemical fiber is generally a composite fiber. In some specific embodiments, the chemical fiber may include inorganic fibers and / or synthetic fibers. The inorganic fibers may include glass fibers and / or ceramic fibers, and the synthetic fibers may include one or a combination of two or more of terylene, nylon, acrylic, polypropylene, vinylon, and chlorofiber. In some specific embodiments, the chemical fiber may be surface-treated to improve its performance, for example, by modifying the surface of the chemical fiber using a silane coupling agent.

[0023] The present invention further provides an application of the acoustic reinforcement material block to a micro-speaker. When the acoustic reinforcement material block is filled into the cavity of a micro-speaker, the acoustic volume of the cavity of the micro-speaker can be virtually expanded, thereby lowering the resonant frequency of the speaker. At the same time, the acoustic reinforcement material block has a layered structure and high mechanical properties, and since it is a general block, it has excellent performance and reliability in application, does not require a separate channel, and reduces the risk of failure due to powder falling.

[0024] The present invention also provides a micro speaker including an upper shell, a lower shell, and a speaker unit, the upper shell and the lower shell forming a cavity, the speaker unit being positioned in the cavity, a sound output hole being provided on one side of the upper shell, the cavity being divided into a front cavity and a back cavity, the front cavity being a cavity between the top of the speaker and the upper shell, the front cavity being in communication with the sound output hole, and the interior of the micro speaker further comprising a front cavity resonant cavity having an air hole in communication with the front cavity and filled with an acoustic reinforcement material.

[0025] In specific embodiments of the present invention, the upper and lower shells are typically hermetically joined (e.g., glued together) to form a cavity, where the upper shell is the top and side casings of the microspeaker, and the lower shell is the bottom casing of the microspeaker. The cavity formed by joining the upper and lower shells can accommodate a speaker unit. The speaker unit may be fixed to the sidewall of the upper shell, and a space is typically provided between the top of the speaker unit and the upper shell (in some specific embodiments, this space is included in the front cavity). A cushioning material such as foam is typically filled between the bottom of the speaker unit and the lower shell. The height of the top of the speaker unit within the microspeaker matches the opening height of the sound output hole. The vertical plane on which the side of the speaker unit facing the sound output hole is located and the horizontal plane on which the top of the speaker unit is located form the boundaries of the front cavity. In this case, the front cavity is considered to be the cavity between the speaker unit and the upper shell, and the back cavity is considered to be the remaining part of the cavity.

[0026] According to a specific embodiment of the present invention, the vent hole is used to communicate the resonant cavity of the front cavity with the front cavity. The size and location of the vent hole are not particularly limited, and those skilled in the art can determine the appropriate size and location of the vent hole according to actual needs as long as the objective of the present invention is ensured. The vent hole may be provided at a port of the resonant cavity of the front cavity, specifically, at the center or side of the resonant cavity of the front cavity. The shape of the vent hole of the resonant cavity of the front cavity may be any of square, rectangular, circular, diamond, and elliptical.

[0027] According to a specific embodiment of the present invention, the position of the resonant cavity of the front cavity is generally not lower than the position of the speaker unit in the vertical direction, i.e., it is generally located above the speaker or installed parallel to the speaker unit.

[0028] According to a specific embodiment of the present invention, the resonant cavity of the front cavity may be provided within the upper shell above the front cavity, for example, above the center or periphery of the front cavity. The resonant cavity of the front cavity may be installed around the speaker unit. In this case, a position limiting protrusion may be provided on the inner top surface of the upper shell to separate the front cavity and the back cavity and prevent electrical connection between them. Specifically, the position limiting protrusion is generally provided vertically downward along the edge of the side of the speaker, and its height matches the distance from the top of the speaker unit to the top of the micro-speaker. The position limiting protrusion, together with the top of the speaker unit and the upper shell, surrounds the front cavity.

[0029] According to a specific embodiment of the present invention, the resonant cavity of the front cavity may be disposed within the upper shell above the back cavity and communicate with the front cavity through the vent hole. In this case, the upper shell may further include a first partition wall and a second partition wall disposed within the micro speaker, the first partition wall and the second partition wall generally being fixed to connect to the inner walls of the side casings. In this case, the upper shell may be considered to include a first casing that is the top casing of the micro speaker, and a second casing (also referred to as a middle casing) that is composed of the side casings of the micro speaker, the first partition wall, and the second partition wall. The first partition wall is used to separate the front cavity from the back cavity, and the boundary of the front cavity includes the vertical surface on which the first partition wall is located, the top surface of the speaker, and the first casing. That is, the front cavity is surrounded by the first partition wall, the top of the speaker unit, the first casing, and the side casing of the micro-speaker, and the back cavity is a cavity other than the front cavity within the cavity. The second partition wall is used to separate the resonant cavity of the front cavity from the back cavity so that there is no electrical connection between the resonant cavity of the front cavity and the back cavity. In some specific embodiments, the first casing and the second casing may be hermetically fixed by a method such as adhesive bonding or ultrasonic welding.

[0030] According to a specific embodiment of the present invention, the inner wall of the upper shell may further include a boss (generally an annular boss) for fixing the speaker. When the upper shell includes a first casing and a second casing, the boss can be considered to be part of the second casing, and the boss can abut between the first partition and the side casing in which the sound emission hole is located and / or between the side casing on the side adjacent to the sound emission hole. In the vertical direction, the boss is generally provided in the center of the micro speaker.

[0031] According to a specific embodiment of the present invention, the speaker unit includes a vibrating diaphragm, a voice coil assembly fixedly connected to the vibrating diaphragm, and a magnetic circuit system, and an edge of the vibrating diaphragm may be fixed to the magnetic circuit system. When the resonant cavity of the front cavity is located above the front cavity, the horizontal surface on which the vibrating diaphragm of the speaker unit is located and the upper shell form the front cavity. When the resonant cavity of the front cavity is located above the back cavity, i.e., when the micro-speaker includes a first partition wall and a second partition wall, the space between the horizontal surface on which the vibrating diaphragm of the speaker unit is located and the first and second casings form the front cavity.

[0032] According to specific embodiments of the present invention, the volume of the acoustic stiffener is generally controlled to 10-90%, preferably 40-60% of the total volume of the front cavity resonant cavity. In some specific embodiments, the location of the acoustic stiffener in the front cavity resonant cavity may be close to or far from the air vent.

[0033] According to a specific embodiment of the present invention, the acoustic reinforcement material may include the acoustic reinforcement block (generally a block) and / or acoustic reinforcement particles, such as zeolite material as disclosed in Patent Application No. 201510388038.5 (Publication No.: CN105049997A, Title: Sound Improvement Speaker System), the entire text of which is incorporated herein by reference.

[0034] According to a specific embodiment of the present invention, when the resonant cavity of the front cavity is filled with the acoustic reinforcement material block, a cushion material may be further provided inside the resonant cavity of the front cavity, the cushion material fitting to the inner wall of the cavity. According to a specific embodiment of the present invention, when the resonant cavity of the front cavity is filled with acoustic reinforcement particles, the ventilation hole may further be provided with a mesh cloth to separate the acoustic reinforcement particles from the front cavity and prevent the acoustic reinforcement particles from falling out of the resonant cavity of the front cavity.

[0035] According to a specific embodiment of the present invention, the acoustic reinforcement block may be filled in other positions in the back cavity than the resonant cavity of the front cavity, virtually expanding the volume of the back cavity and further improving the low-frequency performance of the speaker. The present invention further provides an electronic device including the micro speaker.

[0036] The beneficial effects of the present invention are as follows:

[0037] 1. The acoustic reinforcement block provided by the present invention uses a skeleton material as a carrier, and additives such as porous materials are directly supported on the carrier, thereby avoiding variations in the performance of the acoustic reinforcement block caused by the difficulty of additive dispersion during production. At the same time, the use of a skeleton material can significantly improve the mechanical strength of the acoustic reinforcement block, and the addition of auxiliary agents can significantly improve the fall prevention reliability of the acoustic reinforcement block and stabilize the performance of the acoustic reinforcement block.

[0038] 2. When sheet-shaped acoustical reinforcement blocks are stacked and used as a single unit, the voids between the layers of the acoustical reinforcement blocks and the voids between the framework materials stacked on the acoustical reinforcement blocks provide sufficient airflow passages, allowing sufficient interaction between the gas and the acoustical reinforcement blocks. This method not only ensures that the mechanical properties of the acoustical reinforcement blocks are excellent and is advantageous for improving the acoustic characteristics of the speaker, but also avoids the need to provide separate channels in the acoustical reinforcement blocks, reducing the risk of the acoustical reinforcement blocks breaking or falling apart.

[0039] 3. In the micro speaker provided by the present invention, by filling the front resonant cavity with a certain proportion of acoustic reinforcement material blocks, the flatness of the high-frequency performance curve of the speaker with a front resonant cavity can be improved more effectively than when a filter structure is provided, and at the same time, the manufacturing process of the micro speaker provided by the present invention is simple and the difficulty of mold making can be reduced. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a schematic diagram of a layer-by-layer structure of scaffolding in some embodiments of the present invention. [Figure 2] FIG. 2 is a structural schematic diagram of the acoustic reinforcement block of the first embodiment when it is positioned within the resonant cavity of the front cavity. [Figure 3] FIG. 10 is a structural schematic diagram of a micro speaker according to a second embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along the line AA in FIG. [Figure 5] FIG. 10 is a structural schematic diagram of a micro-speaker according to a third embodiment. [Figure 6] FIG. 10 is a structural schematic diagram of a micro-speaker according to a third embodiment. [Figure 7] FIG. 6 is a cross-sectional view taken along the AA direction in FIG. 5. [Figure 8] FIG. 6 is a cross-sectional view taken along the line BB in FIG. 5. [Figure 9] 1 shows performance test curves of the micro speakers of Example 2 and Comparative Example 1. [Explanation of symbols]

[0041] 1 - upper shell, 2 - lower shell, 4 - speaker unit, 5 - back cavity, 6 - front cavity, 7 - sound emission hole, 8 - resonance cavity of front cavity, 81 - vent, 82 - acoustic reinforcement, 11 - first casing, 31 - second casing, 41 - vibration diaphragm, 61 - position limiting protrusion, 91 - first partition, 92 - second partition, 93 - boss. DETAILED DESCRIPTION OF THE INVENTION

[0042] In order to make the technical features, objectives and beneficial effects of the present invention more clearly understood, the technical solutions of the present invention are described in detail below, but should not be understood as limiting the scope of the present invention.

[0043] In describing the present invention, orientations or positional relationships indicated by terms such as "center," "upper," "lower," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are based on orientations or positional relationships shown in the drawings, and are merely for the convenience and simplification of the description of the present invention, and should not be understood as indicating or implying that the referred-to devices or elements must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0044] Additionally, the terms "first" and "second" are for descriptive purposes only and should not be understood to indicate or imply relative importance or the number of referenced technical features. Thus, a feature qualified as "first" or "second" can explicitly or implicitly include one or more of that feature. In describing the present invention, "plurality" means two or more than two, unless otherwise specified.

[0045] Example 1 This example provides an acoustical reinforcement block containing 6.4% polyacrylate suspension, 0.1% CMC, and 12.6% skeleton material, with the remainder being a porous material. The porous material used is an MFI molecular sieve with a Si / M mass ratio of 350 (where M is aluminum). The skeleton material used is composed of alternating layers of fiber paper obtained by a wet process from alkali-free chopped glass fiber strands and surface-treated with a silane coupling agent, KH550. The fiber paper has a basis weight of 25 g / m² and a fiber diameter of 7 μm.

[0046] In the manufacture of the acoustical reinforcement block, fiber paper is first cut to a size and shape appropriate for the speaker cavity to be filled. Then, a polyacrylate suspension, CMC, and MFI molecular sieve are mixed to form a uniform slurry, and the cut fiber paper is thoroughly immersed in this slurry to obtain a thin, single-layer acoustical reinforcement block. In some embodiments, multiple fiber papers can be alternately stacked to obtain an acoustical reinforcement block with a multilayered skeleton. The internal structure of this block, as shown in Figure 1, is composed of alternating layers of lamellar and corrugated glass fiber, with additives such as MFI molecular sieves positioned between the layers of the skeleton and permeating the interior of the skeleton. Furthermore, thin blocks of the above single-layer acoustic reinforcement material can be stacked to obtain an acoustic reinforcement material block with interlayer voids. Figure 2 is a schematic diagram of the structure when the acoustic reinforcement material block is filled into a resonant cavity.

[0047] Example 2 This embodiment provides a micro speaker, and Figures 3 and 4 are structural schematic diagrams of the micro speaker. As shown in Figures 3 and 4, the micro speaker includes an upper shell 1, a lower shell 2, and a speaker unit 4.

[0048] The upper shell 1 and the lower shell 2 are glued together to form a sealed cavity, and externally, the upper shell 1 and the lower shell 2 together form a rectangular casing for the micro speaker. Here, the lower shell 2 is the bottom casing of the micro speaker.

[0049] The upper shell 1 is the top and side casing of the micro speaker, and the top and side of the upper shell 1 are formed as a single unit. A sound emission hole 7 is provided on one side of the upper shell 1. The inner top surface of the upper shell 1 is provided with three vertically downward position limiting protrusions 61, which are located on the opposite and adjacent sides of the sound emission hole 7, have a height lower than the height of the cavity, and are spaced apart horizontally at intervals corresponding to the radial dimension of the speaker unit 4.

[0050] The speaker unit 4 is located in the cavity, with foam filling the gap between its bottom and the lower shell 2, and the top edge of the speaker unit 4 fixed between a plurality of position limiting protrusions 61 by adhesive bonding. The speaker unit 4 includes a vibrating diaphragm 41, a voice coil assembly fixedly connected to the vibrating diaphragm 41, and a magnetic circuit system (not shown). The vibrating diaphragm 41 is located at the top of the speaker unit 4, and the edge of the vibrating diaphragm 41 is fixed to the magnetic circuit system. A fixing member extending outward is provided on the edge of the vibrating diaphragm 41, and the fixing member is fixedly engaged with the position limiting protrusions 61. The space between the vibrating diaphragm 41, the position limiting protrusions 61, and the top casing of the upper shell 1 forms a front cavity 6, and the remaining space in the cavity forms a back cavity 5. Specifically, the back cavity 5 includes the side of the speaker unit 4 away from the sound output hole 7, the position limiting protrusion 61, the cavity between the upper shell 1 and the lower shell 2, and the cavities between both sides of the speaker unit 4 and the side casing (the side adjacent to the sound output hole).

[0051] A front cavity resonant cavity 8 is provided inside the upper shell 1 located above the center of the front cavity 6, and a vent hole 81 is provided at one side port of the front cavity resonant cavity 8, and the front cavity resonant cavity 8 and the front cavity 6 are connected by the vent hole 81.

[0052] The side of the front cavity resonant cavity 8 away from the vent hole 81 is filled with the acoustic reinforcement block 82 of Example 1, occupying 50% of the volume of the front cavity resonant cavity 8. The acoustic reinforcement block 82 used in this example has a shape that fits the casing of the front cavity resonant cavity 8, and the specific filling state in the front cavity resonant cavity 8 is as shown in Figure 2. A cushioning material that fits against the inner wall of the cavity may also be provided inside the front cavity resonant cavity 8.

[0053] In some other specific embodiments, the acoustic stiffener block 82 may be replaced with other acoustic stiffeners in the form of particles, in which case the ventilation holes 81 in the front cavity resonant cavity 8 may further be provided with a mesh cloth to separate the acoustic stiffener particles from the front cavity 6 and to prevent the acoustic stiffener particles from falling out of the front cavity resonant cavity 8.

[0054] Example 3 This embodiment provides a micro speaker, and Figures 5 to 8 are structural diagrams of the micro speaker. As shown in Figures 5 to 8, this micro speaker includes an upper shell 1, a lower shell 2, and a speaker unit 4.

[0055] As shown in Figure 6, the upper shell 1 and the lower shell 2 are bonded together to form a sealed cavity, and externally, the upper shell 1 and the lower shell 2 together form a rectangular casing of the micro speaker. The upper shell 1 is the top casing, side casing, and inner casing of the micro speaker, and the lower shell 2 is the bottom casing of the micro speaker.

[0056] The upper shell 1 of this embodiment further includes a first partition wall 91, a second partition wall 92, and an annular boss 93 in addition to the components of the upper shell 1 in Example 2. Specifically, the upper shell 1 of this embodiment includes a first casing 11 and a second casing 31. Here, the first casing 11 is a top casing of the micro speaker, and the second casing (or middle casing) 31 includes a side casing of the micro speaker (hereinafter abbreviated as "side casing"), the first partition wall 91 fixed to the inner wall of the side casing, the second partition wall 92, and the annular boss 93. A sound emission hole 7 is provided on one side of the second casing 31. The first partition wall 91 and the second partition wall 92 are provided along a direction extending from the upper shell 1 to the lower shell 2. The first partition wall 91 is linear.

[0057] The annular boss 93 is provided between the side casing and the first partition wall 91. The vertical distance between the annular boss 93 and the first casing 11 is approximately the same as the vertical height of the first partition wall 91.

[0058] The speaker unit 4 is fixed inside the micro speaker by fitting into the annular boss 93, a space is provided between the top surface of the speaker unit 4 and the first casing 11, and foam is filled between the bottom surface of the speaker unit 4 and the lower shell 2. The speaker unit 4 includes a vibrating diaphragm 41, a voice coil assembly fixedly connected to the vibrating diaphragm 41, and a magnetic circuit system (not shown). The vibrating diaphragm 41 is located at the top of the speaker unit 4, and the edge of the vibrating diaphragm 41 is fixed to the magnetic circuit system. The edge of the vibrating diaphragm 41 is provided with a fixing member extending outward, and the fixing member is engaged and fixed to the first partition wall 91.

[0059] The cavity between the side casing where the sound output hole 7 is located, the first casing 11, the speaker unit 4, and the first partition wall 91 is the front cavity 6, and the cavity other than the front cavity 6 is the back cavity 5. Specifically, the back cavity 5 includes a vertical surface on which the side of the first partition wall 91 away from the sound output hole 7 is located, a cavity between the first casing 11, the lower shell 2, and the side casing, and a cavity between the vertical surface on which the side of the first partition wall 91 away from the sound output hole 7 is located, the vibrating diaphragm 41, and the lower shell 2.

[0060] The second partition wall 92 has a bent line shape and is located within the back cavity 5. Together with the side casings, the first partition wall 91, and the first casing 11, the second partition wall 92 surrounds and forms the resonant cavity 8 of the front cavity. The resonant cavity 8 of the front cavity is disposed adjacent to the speaker unit 4 and is located on the side of the back cavity 5 closer to the front cavity. The resonant cavity 8 of the front cavity has an air vent 81 formed in the first partition wall 91, and the resonant cavity 8 of the front cavity communicates with the front cavity 6 via the air vent 81. The opening dimension of the air vent 81 is smaller than the height of the resonant cavity of the front cavity. The side of the resonant cavity 8 of the front cavity away from the air vent 81 is filled with the acoustic reinforcement block 82 of Example 1, occupying 50% of the volume of the resonant cavity 8 of the front cavity. The acoustic reinforcement block 82 used in this embodiment has a shape that fits the cavity casing of the front cavity resonant cavity 8, and the specific filling state in the front cavity resonant cavity 8 is as shown in Figure 2. Inside the front cavity resonant cavity 8, a cushioning material that fits to the cavity wall may also be provided.

[0061] In some other specific embodiments, the acoustic stiffener block 82 may be replaced by other acoustic stiffeners in the form of particles, in which case the ventilation holes 81 in the front cavity resonant cavity 8 may be provided with a mesh cloth to separate the particles from the front cavity 6 and to prevent the acoustic stiffener particles from falling out of the front cavity resonant cavity 8.

[0062] Comparative Example 1 This comparative example provides a micro speaker whose structure is almost the same as that of the micro speaker of Example 2, except that nothing is filled into the resonant cavity 8 of the front cavity in the micro speaker of this comparative example (including not filling it with the acoustic reinforcement material block or other acoustic reinforcement material of Example 1).

[0063] Test Example 1 Performance tests were conducted on the microspeaker of Example 2 and the microspeaker of Comparative Example 1, and the measured high-frequency response curves are shown in Figure 9. As can be seen from Figure 9, the high-frequency performance curve of the microspeaker (Example 2) in which the resonant cavity of the front cavity is filled with an acoustic stiffening material block is flatter than that of the microspeaker (Comparative Example 1) in which the acoustic stiffening material block is not filled, indicating that filling the resonant cavity of the front cavity with an acoustic stiffening material block has a significant effect of improving the sound quality of the microspeaker.

Claims

1. A micro speaker, The device includes an upper shell, a lower shell, and a speaker unit, the upper shell and the lower shell forming a cavity, the speaker unit being located in the cavity, and a sound emission hole being provided on one side of the upper shell; The cavity is divided into a front cavity and a back cavity, the front cavity is a cavity between the top of the speaker and the upper shell, and the front cavity is in communication with the sound emission hole; The micro speaker further includes a front cavity resonant cavity having an air vent communicating with the front cavity and filled with an acoustic reinforcement material, When the resonant cavity of the front cavity is located within the upper shell above the front cavity, a position limiting protrusion is further provided on the top surface of the interior of the upper shell to separate the front cavity from the back cavity.

2. The micro-speaker according to claim 1 , wherein the resonant cavity of the front cavity is provided in the upper shell above the front cavity or is provided in the upper shell above the back cavity.

3. 3. The micro-speaker of claim 2, wherein when the resonant cavity of the front cavity is located within the upper shell above the back cavity, the upper shell further includes a first partition wall and a second partition wall provided inside the micro-speaker, the first partition wall being used to separate the front cavity from the back cavity, and the second partition wall being used to separate the resonant cavity of the front cavity from the back cavity.

4. The micro speaker according to claim 1 , wherein the inner wall of the upper shell is further provided with a boss for fixing the speaker unit.

5. 2. The micro-speaker of claim 1, wherein the volume of the acoustic stiffener is 10%-90% of the total volume of the resonant cavity of the front cavity.

6. 6. The micro-speaker of claim 5, wherein the volume of the acoustic stiffener is 40%-60% of the total volume of the resonant cavity of the front cavity.

7. 2. The microspeaker of claim 1, wherein the acoustic reinforcement material is acoustic reinforcement material particles and / or acoustic reinforcement material blocks, the raw materials of which include a porous material, a skeleton material, an adhesive, and an auxiliary agent, the structural skeleton consisting of a single layer of skeleton material or two or more layers of skeleton material stacked alternately, the porous material, adhesive, and auxiliary agent being supported on the structural skeleton, and the skeleton material consisting of layered and / or corrugated fiber paper, fiber cloth, or fiber felt stacked alternately.

8. 8. The micro speaker of claim 7, wherein when the resonant cavity of the front cavity is filled with the acoustic reinforcement block, a cushioning material is provided inside the resonant cavity of the front cavity, the cushioning material fitting to the inner wall of the cavity.

9. The micro-speaker of claim 7, wherein when the resonant cavity of the front cavity is filled with acoustic reinforcement particles, the vent hole is further provided with a mesh cloth.

10. An electronic device comprising the micro-speaker according to claim 1.

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