Loudspeaker module

Abstract

The present application relates to the technical field of acoustoelectronics, and discloses a loudspeaker module. The loudspeaker module comprises: a first MEMS loudspeaker and a second MEMS loudspeaker which are located on two sides of a circuit board and are mounted in a face-down manner, wherein the first MEMS loudspeaker comprises a first diaphragm structure, the first diaphragm structure is electrically connected to a first electrode connection point, and the first diaphragm structure is controlled by the circuit board and generates vibration; the second MEMS loudspeaker comprises a second diaphragm structure, the second diaphragm structure is electrically connected to a second electrode connection point, and the second diaphragm structure is controlled by the circuit board and generates vibration.

Description

speaker module Technical Field

[0001] This application relates to the field of acoustic and electronic technology, and in particular to a loudspeaker module. Background Technology

[0002] A loudspeaker is a transducer that converts electrical signals into sound signals. The working principle of a loudspeaker is that audio electrical energy, through electromagnetic, piezoelectric, or electrostatic effects, causes its cone or diaphragm to vibrate and resonate with the surrounding air, thus producing sound.

[0003] Sound is formed by fluctuating changes in air pressure. A loudspeaker pushes a certain amount of air, causing pressure changes and thus producing a certain amount of sound (sound pressure). Based on current miniaturization efforts, current loudspeaker modules typically incorporate a single loudspeaker structure, controlling the sound pressure by adjusting the effective radius, frequency, distance, and unidirectional stroke of the diaphragm within that structure. However, while miniaturization is achieved, output power cannot be simultaneously increased, resulting in insufficient sound pressure and limited functionality. Summary of the Invention

[0004] To address the aforementioned issues, the main objective of this application is to provide a speaker module that, without altering existing miniaturization practices, allows the speaker module to incorporate two speaker structures, enabling flexible control to create a speaker module with a higher sound pressure level.

[0005] To achieve the above objectives, the present application provides a speaker module, comprising: a housing forming a cavity, the housing having a sound outlet hole extending through the thickness of the housing; a circuit board located within the cavity, the circuit board having a first side and a second side opposite to each other, the first side having a first electrode connection point and the second side having a second electrode connection point; a first MEMS speaker located within the cavity, the first MEMS speaker being mounted upside down on the first side, the first MEMS speaker including a first diaphragm structure electrically connected to the first electrode connection point, the first diaphragm structure being controlled by the circuit board and generating vibration; and a second MEMS speaker located within the cavity, the second MEMS speaker being mounted upside down on the second side, the second MEMS speaker including a second diaphragm structure electrically connected to the second electrode connection point, the second diaphragm structure being controlled by the circuit board and generating vibration.

[0006] Preferably, the first MEMS loudspeaker further includes: a first substrate forming a first cavity, a first diaphragm structure stacked on the first substrate and covering the first cavity, and a first flexible structural layer covering the first diaphragm structure; the first diaphragm structure is a piezoelectric composite diaphragm.

[0007] Preferably, the second MEMS loudspeaker further includes: a second substrate forming a second cavity, a second diaphragm structure stacked on the second substrate and covering the second cavity, and a second flexible structural layer covering the second diaphragm structure; the second diaphragm structure is a piezoelectric composite diaphragm.

[0008] Preferably, the first diaphragm structure includes a plurality of sub-diaphragms, with slits between adjacent sub-diaphragms; the first flexible structural layer completely covers the slits.

[0009] Preferably, the bottom surface of the first substrate is a hexagonal three-dimensional structure, and the bottom surface of the first diaphragm structure is a hexagonal three-dimensional structure.

[0010] Preferably, the first diaphragm structure includes six sub-diaphragms, each sub-diaphragm being a polygonal structure extending from the edge of the first substrate toward the center point of the first substrate, with the top of the six polygonal structures facing the center point and the bottom edge of each polygonal structure located on the first substrate.

[0011] Preferably, the polygonal structure is a three-dimensional structure composed of isosceles triangles, with the vertices of the isosceles triangles facing the center point.

[0012] Preferably, the first flexible structural layer is an organic thin film layer.

[0013] Preferably, the first diaphragm structure includes a stacked support layer, a bottom electrode layer, a piezoelectric layer, a top electrode layer, and a protective layer; the support layer and the first flexible structure layer are spaced apart.

[0014] Preferably, the circuit board has a through hole in the middle, and the through hole is square or circular in shape.

[0015] The beneficial effects of this application are as follows: The speaker module of this application is a bidirectional driven speaker module. Based on the fact that the first MEMS speaker and the second MEMS speaker on both sides of the circuit board can be driven by different driving signals, at the same time, the vibration direction of the first diaphragm structure is opposite to that of the second diaphragm structure, so that the sound waves generated by the first MEMS speaker and the second MEMS speaker pushing the air are superimposed at the sound outlet, which can improve the sound pressure level performance of the speaker; secondly, at another time, the vibration direction of the first diaphragm structure is the same as that of the second diaphragm structure, so that the sound waves generated by the first MEMS speaker and the second MEMS speaker pushing the air are canceled at the sound outlet, thereby enabling more flexible control. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0017] Figure 1 is a structural schematic diagram of a speaker module provided in an embodiment of this application;

[0018] Figure 2 is an exploded view of the speaker module shown in Figure 1;

[0019] Figure 3 is a cross-sectional view of the speaker module shown in Figure 1;

[0020] Figure 4 is a schematic diagram of the structure of the first MEMS loudspeaker in the loudspeaker module shown in Figure 1;

[0021] Figure 5 is a cross-sectional perspective view of the first MEMS speaker in the speaker module shown in Figure 1;

[0022] Figure 6 is a partial cross-sectional view of the first diaphragm structure in the first MEMS loudspeaker shown in Figure 1;

[0023] Figure 7 is a schematic diagram of the structure of the second MEMS speaker in the speaker module shown in Figure 1;

[0024] Figure 8 is a cross-sectional perspective view of the second MEMS speaker in the speaker module shown in Figure 1. Embodiments of the present invention

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of this application to enable the reader to better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0026] In the embodiments of this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0027] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0028] Furthermore, the terms "installation," "setup," "equipped with," "opening," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0029] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0030] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0031] Referring to Figures 1-8, embodiments of this application provide a speaker module, comprising: a housing 10 forming a cavity, the housing 10 having a sound outlet 102 penetrating the thickness of the housing 10; a circuit board 110 located within the cavity, the circuit board 110 having opposing first surfaces 111 and second surfaces 112, the first surface 111 having a first electrode connection point 113, and the second surface 112 having a second electrode connection point (not marked); and a first MEMS (Micro-Electro Mechanical) located within the cavity. The system (microelectromechanical system) speaker 150, the first MEMS speaker 150 is mounted upside down on the first surface 111, the first MEMS speaker 150 includes a first diaphragm structure 151, the first diaphragm structure 151 is electrically connected to the first electrode connection point 113, the first diaphragm structure 151 is controlled by the circuit board 110 and generates vibration; the second MEMS speaker 160 is located in the cavity, the second MEMS speaker 160 is mounted upside down on the second surface 112, the second MEMS speaker 160 includes a second diaphragm structure 161, the second diaphragm structure 161 is electrically connected to the second electrode connection point, the second diaphragm structure 161 is controlled by the circuit board 110 and generates vibration.

[0032] The speaker module housing 10 is used to provide physical protection while minimizing the attenuation of the desired sound.

[0033] Referring to Figures 1-3, the outer shell 10 includes a first outer shell 121 and a second outer shell 122 that engage with each other. The first outer shell 121 and the second outer shell 122 constitute a first sub-chamber 101 and a second sub-chamber 103, and the first sub-chamber 101 and the second sub-chamber 103 together constitute a chamber.

[0034] The outer casing 10 has sound vents (not shown) to balance the pressure between the first sub-chamber 101 and the second sub-chamber 103 and the outside environment. This application does not limit the number or shape of the sound vents; those skilled in the art can set the shape and number of the sound vents according to actual needs.

[0035] The housing 10 has two opposing through holes, one of which serves as a sound outlet 102, and the other serves as a connection terminal for the circuit board.

[0036] In one embodiment, the circuit board 110 may pass through a through hole in the housing as shown in FIG1, and circuit connection points (e.g., a first circuit connection point and a second circuit connection point) are provided on the surface of the circuit board 110. The circuit connection points are used to connect with external circuit components and transmit a first signal and a second signal. The first signal is used to control the vibration of the first diaphragm structure 151, and the second signal is used to control the vibration of the second diaphragm structure 161.

[0037] It should be noted that although the through hole of the circuit board 110 in the housing 10 shown in Figure 1 is directly opposite the sound outlet hole 102, optionally, the through hole of the circuit board 110 and the sound outlet hole 102 can be on different sides of the housing 10 or on other substrates that meet the design requirements.

[0038] Referring to Figure 2, the circuit board 110 provided in this embodiment has a through hole 115 in the middle, or the circuit board 110 is configured as an annular shape, such as a square annular shape or a circular annular shape. This through hole 115 penetrates the thickness of the circuit board 110 and is directly opposite to and communicates with the first cavity 154 of the first MEMS speaker 150 and the second cavity 164 of the second MEMS speaker 160, respectively. The through hole 115 can serve as the vibration space of the first diaphragm structure 151 and the vibration space of the second diaphragm structure 161.

[0039] The through hole 115 can be polygonal or circular. The polygon can be square, triangle, hexagon, octagon or any other shape.

[0040] The flip-chip method refers to directly interconnecting the first MEMS speaker 150 downwards to the circuit board 110 through the protrusion (third electrode connection point) on the first MEMS speaker 150; and directly interconnecting the second MEMS speaker 160 downwards to the circuit board 110 through the protrusion (fourth electrode connection point) on the second MEMS speaker 160. By using the flip-chip method, the planar area of ​​the first MEMS speaker 150 and the second MEMS speaker 160 can be saved, thereby occupying less space and having a smaller size, saving space and achieving miniaturization.

[0041] Referring to Figure 4, the first MEMS loudspeaker 150 further includes: a first substrate 153 forming a first cavity 154, a first diaphragm structure 151 stacked on the first substrate 153 and covering the first cavity 154, and a first flexible structure layer 157 covering the first diaphragm structure 151; the first diaphragm structure 151 is a piezoelectric composite diaphragm.

[0042] The bottom surface shape of the first substrate 153 of the first MEMS loudspeaker 150 can be circular, square, hexagonal, octagonal or any equilateral shape.

[0043] In this embodiment, the bottom surface of the first substrate 153 of the first MEMS loudspeaker 150 is a hexagonal three-dimensional structure. The first substrate 153 is configured as a hexagonal ring. The first diaphragm structure 151 and the first substrate 153 surround to form a first cavity 154, which penetrates the first substrate 153 and serves as the vibration space of the first MEMS loudspeaker 150. Optionally, the first substrate 153 can be a single-crystal silicon substrate or other substrates that meet the design requirements.

[0044] When the first substrate 153 is configured as a hexagonal ring, the inner and outer edges and connections of the first substrate 153 are chamfered, especially rounded chamfers. This can reduce the sharp structures inside the first MEMS speaker 150, which is beneficial for product assembly. At the same time, it can prevent sharp structures on the first substrate 153 from contacting and damaging other internal components of the first MEMS speaker 150.

[0045] The bottom surface of the first diaphragm structure 151 can be circular, square, hexagonal, octagonal, or any equilateral shape. The bottom surface of the first diaphragm structure 151 is a hexagonal three-dimensional structure, corresponding to the shape of the first substrate 153.

[0046] Optionally, the first diaphragm structure 151 includes a plurality of sub-diaphragms 1511, with slits 155 between adjacent sub-diaphragms 1511. For example, the first diaphragm structure includes four sub-diaphragms, five sub-diaphragms, or six sub-diaphragms, etc. Of course, those skilled in the art can also provide other numbers of sub-diaphragms and other shapes of first substrates according to actual needs.

[0047] The first diaphragm structure 151 includes six sub-diaphragms 1511. Each sub-diaphragm 1511 is a polygonal structure extending from the edge of the first substrate 153 toward the center point of the first substrate 153. The top of each polygonal structure faces the center point, and the bottom edge of each polygonal structure is located on the first substrate 153.

[0048] Referring to Figures 4 and 5, this application uses a first diaphragm structure 151 comprising six sub-diaphragms 1511 as an example. Each sub-diaphragm 1511 is a three-dimensional structure composed of isosceles triangles. The vertices of the six isosceles triangles face the center point of the first substrate 153 and form a hexahedral structure. The base of each isosceles triangle is located on the first substrate 153. The first cavity 154 formed by the first substrate 153 is also hexahedral in shape.

[0049] Optionally, referring to FIG6, the first diaphragm structure 151 includes a stacked support layer 185, a bottom electrode layer 184, a piezoelectric layer 183, a top electrode layer 182, and a protective layer 181.

[0050] The material of the support layer 185 can be SOI (Silicon On Insulation, an insulating material for crystalline silicon). The material of the support layer 185 can be silicon dioxide or other insulating materials.

[0051] The bottom electrode layer 184 can be made of platinum.

[0052] The material of the piezoelectric electrode layer 183 can be PZT (Lead Zirconate Titanate). PZT thin film has a high piezoelectric constant, which can improve electromechanical conversion efficiency and increase speaker driving speed.

[0053] The top electrode layer 182 can be made of gold or a platinum alloy. The protective layer 182 can be made of silicon nitride.

[0054] Optionally, referring to Figure 5, an insulating layer 159 is further provided between the first diaphragm structure 151 and the first substrate 153. The insulating layer 159 is made of silicon dioxide, which can reduce the parasitic capacitance between the two compared to the structure without an insulating layer.

[0055] It should be noted that the multiple sub-diaphragms shown in Figures 2 to 8 of this embodiment are all the same in size and shape. In other embodiments, the multiple sub-diaphragms may be set to have different sizes and shapes according to actual needs.

[0056] An insulating adhesive 107 is provided between the first diaphragm structure 151 and the circuit board 110. The insulating adhesive has through holes, which can accommodate a first conductive metal layer 108. The first conductive metal layer 108 is used to connect the first electrode connection point 113 of the circuit board 110 and the third electrode connection point (not marked) on the first diaphragm structure 151.

[0057] The insulating adhesive 107 can be made of silicone. The first conductive metal layer 108 can be made of conductive adhesive, such as silver paste.

[0058] Optionally, the first flexible structural layer 157 and the support layer 185 are spaced apart, with a piezoelectric layer containing the first diaphragm structure in between. The first flexible structural layer 157 is a complete sheet structure without any gaps. The first flexible structural layer 157 completely covers the slit 155, so that the overall structure of the first MEMS speaker 150 is free of gaps, resulting in more outstanding performance in the mid-to-high frequency range.

[0059] The first flexible structural layer 157 includes at least one organic thin film layer. The Young's modulus of the first flexible structural layer 157 is less than that of the piezoelectric diaphragm, and the Young's modulus of the first flexible structural layer 157 is 100 MPa to 50 GPa.

[0060] Referring to Figures 7 and 8, the second MEMS loudspeaker 160 further includes: a second substrate 163 forming a second cavity 164, a second diaphragm structure 161 stacked on the second substrate 163 and covering the second cavity 164, and a second flexible structure layer 167 covering the second diaphragm structure 161; the second diaphragm structure 161 is a piezoelectric composite diaphragm.

[0061] The second diaphragm structure 161 includes a plurality of second sub-diaphragms 1611, with a second slit 165 between adjacent second sub-diaphragms 1611. Each second sub-diaphragm 1611 is a three-dimensional structure composed of isosceles triangles, with the vertices of the six isosceles triangles facing the center point of the second substrate 163 and forming a hexahedral structure, and the base of each isosceles triangle located on the second substrate 163.

[0062] A second insulating layer 169 is also provided between the second diaphragm structure 161 and the second substrate 163. An insulating adhesive 107 is provided between the second diaphragm structure 151 and the circuit board 110. The insulating adhesive 107 has through holes, and the through holes can accommodate a second conductive metal layer 118. The second conductive metal layer 118 is used to connect the second electrode connection point of the circuit board 110 and the fourth electrode connection point 162 on the second diaphragm structure 161.

[0063] It should be noted that the second diaphragm structure 161, the fourth electrode connection point 162, the second substrate 163, and the second flexible structure layer 167 in the second MEMS loudspeaker 160 can be referred to the descriptions of the first diaphragm structure 151, the third electrode connection point, the first substrate 153, and the first flexible structure layer 157 in the first MEMS loudspeaker 150, and will not be elaborated here.

[0064] In one example, the structures of the first MEMS speaker and the second MEMS speaker are not the same. The structure of the first MEMS speaker is as described in the first MEMS speaker 150 in the above embodiment, and the structure of the second MEMS speaker is a speaker known to those skilled in the art.

[0065] In another example, the structures of the first MEMS speaker and the second MEMS speaker are not the same. The structure of the second MEMS speaker is as described in the above embodiment, which is the second MEMS speaker 160. The structure of the first MEMS speaker is a speaker known to those skilled in the art.

[0066] In yet another example, the first MEMS speaker 150 and the second MEMS speaker 160 have the same structure.

[0067] Based on the design of the first MEMS speaker 150 and the second MEMS speaker 160 in the speaker module, the first MEMS speaker 150 and the second MEMS speaker 160 can be driven simultaneously. This causes the vibration direction of the first diaphragm structure 151 in the first MEMS speaker 150 to be opposite to the vibration direction of the second diaphragm structure 161 in the second MEMS speaker 160. This causes the sound waves generated by the first MEMS speaker 150 pushing the air and the sound waves generated by the second MEMS speaker 160 pushing the air to be superimposed at the sound outlet 102, thereby generating a higher sound pressure level, such as a sound pressure level of 2dB to 6dB.

[0068] When the first signal received by the first MEMS speaker 150 and the second signal received by the second MEMS speaker 160 are controlled respectively, the corresponding electrical signals can drive the first MEMS speaker 150 and the second MEMS speaker 160 respectively, so that in some frequency bands, the vibration direction of the first diaphragm structure 151 is opposite to the vibration direction of the second diaphragm structure 161, and the sound waves are superimposed; in another frequency band, the vibration direction of the first diaphragm structure 151 is the same as the vibration direction of the second diaphragm structure 161, and the sound waves are canceled, thereby enabling more flexible control.

[0069] It should be noted that the above embodiments only describe the features of the first MEMS speaker, and do not describe the features of the second MEMS speaker in detail. The second MEMS speaker is the same as the first MEMS speaker, so the feature positions of the second MEMS speaker can be referenced from those of the first MEMS speaker, and will not be described in detail here.

[0070] Those skilled in the art will understand that the above embodiments are specific implementations of this application, and in practical applications, various changes can be made in form and detail without departing from the spirit and scope of this application.

Claims

1. A speaker module, comprising: The outer shell forms a cavity and has a sound outlet that extends through the thickness of the outer shell; A circuit board located within the cavity, the circuit board having a first side and a second side facing each other, the first side having a first electrode connection point and the second side having a second electrode connection point; A first MEMS loudspeaker is located inside the cavity. The first MEMS loudspeaker is mounted upside down on the first surface. The first MEMS loudspeaker includes a first diaphragm structure. The first diaphragm structure is electrically connected to the first electrode connection point. The first diaphragm structure is controlled by the circuit board and generates vibration. The second MEMS loudspeaker is located inside the cavity and is mounted upside down on the second surface. The second MEMS loudspeaker includes a second diaphragm structure, which is electrically connected to the second electrode connection point. The second diaphragm structure is controlled by the circuit board and generates vibration.

2. The speaker module according to claim 1, wherein, The first MEMS loudspeaker further includes: a first substrate forming a first cavity, a first diaphragm structure stacked on the first substrate and covering the first cavity, and a first flexible structural layer covering the first diaphragm structure; the first diaphragm structure is a piezoelectric composite diaphragm.

3. The speaker module according to claim 1 or 2, wherein, The second MEMS loudspeaker further includes: a second substrate forming a second cavity, a second diaphragm structure stacked on the second substrate and covering the second cavity, and a second flexible structural layer covering the second diaphragm structure; the second diaphragm structure is a piezoelectric composite diaphragm.

4. The speaker module according to claim 2, wherein, The first diaphragm structure includes multiple sub-diaphragms with slits between adjacent sub-diaphragms; the first flexible structural layer completely covers the slits.

5. The speaker module according to claim 4, wherein, The bottom surface of the first substrate is a hexagonal three-dimensional structure; the bottom surface of the first diaphragm structure is a hexagonal three-dimensional structure.

6. The speaker module according to claim 5, wherein, The first diaphragm structure includes six sub-diaphragms, each sub-diaphragm being a polygonal structure extending from the edge of the first substrate toward the center point of the first substrate, with the top of each of the six polygonal structures facing the center point and the bottom edge of each polygonal structure located on the first substrate.

7. The speaker module according to claim 6, wherein, The polygonal structure is a three-dimensional structure composed of isosceles triangles, with the vertices of the isosceles triangles facing the center point.

8. The speaker module according to claim 2, wherein, The first flexible structural layer is an organic thin film layer.

9. The speaker module according to claim 2, wherein, The first diaphragm structure includes a stacked support layer, a bottom electrode layer, a piezoelectric layer, a top electrode layer, and a protective layer; the support layer and the first flexible structure layer are spaced apart.

10. The loudspeaker module according to claim 1, wherein, The circuit board has a through hole in the middle, and the through hole can be polygonal or circular in shape.

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