Micro electro mechanical system loudspeaker and electronic equipment

Abstract

The invention discloses a micro electro mechanical system loudspeaker and electronic equipment. The MEMS speaker includes: a substrate structure; the first electrode is positioned on one side, far away from the first substrate, of the second substrate; the piezoelectric film layer is positioned on one side, far away from the substrate structure, of the first electrode; the second electrode is located on the side, away from the first electrode, of the piezoelectric film layer, and the second electrode comprises a plurality of second sub-electrodes which are electrically connected with one another; the supporting layer is located on the side, away from the first electrode, of the piezoelectric film layer, the supporting layer comprises a supporting ring and a supporting column, and the supporting ring is located at the edge of the piezoelectric film layer; the hard vibrating diaphragm layer is located on the side, away from the piezoelectric film layer, of the supporting layer, and the hard vibrating diaphragm layer comprises a bending structure and a plane structure. The invention provides a micro-electro-mechanical system loudspeaker and electronic equipment, which can improve the output performance of the micro-electro-mechanical system loudspeaker and reduce the manufacturing cost of the micro-electro-mechanical system loudspeaker.

Description

Technical Field

[0001] The present invention relates to the technical field of loudspeakers, and in particular to a micro-electromechanical system loudspeaker and electronic equipment. Background Art

[0002] Speakers have been widely used in computers, smart phones, headphones, earplugs, high-fidelity hearing aids, the Internet of Things and other fields. In recent years, with the growing demand for miniaturized, low-cost, and low-power consumer electronic products, the demand for small and micro-micro-electro-mechanical system (MEMS) speakers has increased. Compared with traditional speakers such as electromagnetic speakers, piezoelectric MEMS speakers have the advantages of simple structure, small size, and low cost; and compared with capacitive speakers, which are also MEMS devices, piezoelectric MEMS speakers have the advantages of strong environmental tolerance, simple circuit ASIC design, and high sensitivity. Recently, they have become a research hotspot.

[0003] like Figure 1 and Figure 2 As shown, Figure 1 It is a structural schematic diagram of a piezoelectric MEMS speaker in a non-vibration state provided by the related technology. Figure 2 It is a structural schematic diagram of a piezoelectric MEMS speaker under vibration provided by the related technology. The piezoelectric MEMS speaker usually drives the piezoelectric film 110 to drive the silicon film 120 to vibrate up and down, thereby producing sound. Usually, due to the fully enclosed constraint conditions between the entire piezoelectric film 110 and the supporting frame 130 and the limited vibration amplitude caused by the residual stress, the piezoelectric MEMS speaker generally performs slit etching on the piezoelectric film 110 to form slits 111, so that the entire piezoelectric film 110 is separated into several independent smaller diaphragms 112, and the constraint at one end of the piezoelectric film 110 is released to obtain a greater degree of freedom, thereby bringing a larger amplitude and sound pressure level (SPL), where the sound pressure level refers to the total intensity of the sound received by the listener.

[0004] However, for the speaker, the air leaking through the slit 111 will cause sound pressure loss due to acoustic short circuit (acoustic short circuit means that the sound waves are in opposite phases when the diaphragm of the speaker moves forward or backward, resulting in the sound waves canceling each other out), making it difficult for the performance of the piezoelectric MEMS speaker to reach the level of a traditional speaker. The sound pressure level SPL of the speaker follows the following formula:

[0005] SPL∝A·f·d

[0006] Wherein, A is the effective diaphragm area, f is the signal frequency, and d is the equivalent vibration displacement of the diaphragm at the frequency. It can be seen from the formula that when the slit 111 is wider, the effective diaphragm area is smaller, and the output sensitivity and sound pressure level of the speaker are lower, especially for low-frequency sound source signals.

[0007] In addition, various current speaker structures all have the problem of small overall effective diaphragm area. Figure 3 yes Figure 1 The simulation results of the structure shown in the figure under vibration are shown in Figure 1. Figure 3 After applying an external electric field drive, although the constraints of the entire diaphragm have been reduced by etching the slits, the working mode of the piezoelectric film determines that the diaphragm will basically not deform at the fixed end (i.e., the intersection with the base), and the farther away from the fixed end and closer to the free end near the slit, the greater the deformation. This makes it difficult for piezoelectric MEMS speakers to effectively utilize their diaphragm area. Although the diaphragm area is large, the area that can effectively vibrate and produce sound is extremely limited.

[0008] In addition, during the manufacturing process, the piezoelectric film will have a certain amount of residual stress, which will cause the diaphragm to warp and the vibration output of the diaphragm to be distorted, such as the different initial positions of multiple diaphragms and vibration distortion. Moreover, since the residual stress is affected by the process conditions and has a certain degree of randomness, it is difficult to control and will also have a certain impact on the yield of the device.

[0009] In order to compensate for the SPL loss caused by the slit and improve the consistency and uniformity between independent diaphragms, a commonly used method is to obtain the basic structure of the piezoelectric MEMS microphone, use it as a driving device, and attach an additional diaphragm on its basis.

[0010] However, after the MEMS device process is completed, the corresponding structure of the diaphragm is additionally attached. This method requires additional manual assembly. Due to the small size of MEMS devices, high assembly precision is required, which will lead to higher labor costs and reduce production efficiency, thus causing MEMS devices to lose their original advantages such as high process consistency, mass production, and low cost. Summary of the invention

[0011] The present invention provides a micro-electromechanical system loudspeaker and an electronic device, which can improve the output performance of the micro-electromechanical system loudspeaker and reduce the manufacturing cost of the micro-electromechanical system loudspeaker.

[0012] According to one aspect of the present invention, a micro-electromechanical system speaker is provided, the micro-electromechanical system speaker comprising:

[0013] A substrate structure, wherein the substrate structure comprises a first substrate and a second substrate which are stacked; the first substrate comprises a first through hole, the second substrate comprises a plurality of first slits, and each of the first slits is connected to the first through hole;

[0014] A first electrode is located on a side of the second substrate away from the first substrate, the first electrode comprises a plurality of second slits, and the second slits are connected to the first slits;

[0015] a piezoelectric film layer, located on a side of the first electrode away from the substrate structure, the piezoelectric film layer comprising a plurality of third slits, the third slits being connected to the second slits;

[0016] A second electrode is located at a side of the piezoelectric film layer away from the first electrode, the second electrode comprises a plurality of second sub-electrodes electrically connected to each other, and a gap between two adjacent second sub-electrodes comprises the first slit, the second slit and the third slit;

[0017] A support layer, located on a side of the piezoelectric film layer away from the first electrode, wherein the support layer comprises a support ring and a support column, the support ring is located at the edge of the piezoelectric film layer, and the support ring is arranged around the support column;

[0018] The hard diaphragm layer is located on a side of the support layer away from the piezoelectric film layer, and the hard diaphragm layer includes a bending structure and a planar structure.

[0019] Optionally, the bending structure includes a first bending substructure;

[0020] The first bending substructure is adjacent to the supporting ring and surrounds one side of the supporting ring close to the supporting column.

[0021] Optionally, the bending structure further includes a plurality of second bending substructures;

[0022] The vertical projections of the plurality of second bending substructures on the substrate structure surround the vertical projection of the support column on the substrate structure, and the vertical projections of the plurality of second bending substructures on the substrate structure are distributed in a whirlwind manner.

[0023] Optionally, the planar structure includes a first planar substructure and a second planar substructure;

[0024] The thickness of the first planar substructure is the same as the thickness of the second planar substructure;

[0025] The first planar substructure is located on a surface of the support layer away from the piezoelectric film layer;

[0026] The first distance is smaller than the second distance, wherein the first distance is the distance between the surface of the first planar substructure away from the substrate structure and the surface of the substrate structure close to the first planar substructure, and the second distance is the distance between the surface of the second planar substructure away from the substrate structure and the surface of the substrate structure close to the first planar substructure.

[0027] Optionally, the bending structure is bent along the thickness direction of the substrate structure;

[0028] The third distance is equal to the second distance, wherein the third distance is the maximum distance between a surface of the bending structure away from the substrate structure and a surface of the substrate structure close to the bending structure.

[0029] Optionally, a vertical projection of the second slit on the second substrate covers the first slit;

[0030] A vertical projection of the third slit on the second substrate covers a vertical projection of the second slit on the second substrate.

[0031] Optionally, the support layer has a thickness ranging from 50 μm to 150 μm.

[0032] Optionally, the first substrate includes a first sub-substrate and a second sub-substrate;

[0033] The second sub-substrate is located between the first sub-substrate and the second substrate;

[0034] The first sub-substrate includes a first sub-via;

[0035] The second sub-substrate includes a second sub-through hole;

[0036] The first sub-through hole is connected with the second sub-through hole to form the first through hole.

[0037] Optionally, the MEMS speaker provided in this embodiment further includes an exposed first solder pad and a second solder pad;

[0038] The first pad is electrically connected to the first electrode, and the second pad is electrically connected to the second electrode.

[0039] According to another aspect of the present invention, an electronic device is provided. The electronic device includes the micro-electromechanical system speaker provided by any embodiment of the present invention.

[0040] An embodiment of the present invention provides a micro-electromechanical system speaker, which includes a substrate structure, a first electrode, a piezoelectric film layer, a second electrode, a support layer and a hard diaphragm layer. The substrate structure includes a first substrate and a second substrate that are stacked. The first electrode is located on a side of the second substrate away from the first substrate, and the piezoelectric film layer is located on a side of the first electrode away from the substrate structure; the second electrode is located on a side of the piezoelectric film layer away from the first electrode. The support layer is located on a side of the piezoelectric film layer away from the first electrode, and the support layer includes a support ring and a support column, and the support ring is located at the edge of the piezoelectric film layer and surrounds the support column. The hard diaphragm layer is located on a side of the support layer away from the second electrode, and the hard diaphragm layer includes a bent structure and a planar structure, and the vertical projection of the bent structure on the substrate structure surrounds the vertical projection of the support column on the substrate structure. The support layer in this embodiment constructs an additional cavity on one side of the piezoelectric diaphragm layer. The support layer can transmit the maximum center vibration generated by the piezoelectric film layer to the hard diaphragm layer on the top, and the hard diaphragm layer replaces the piezoelectric film layer to vibrate and produce sound. Compared with other structures, the maximum center displacement of the piezoelectric braking structure can be fully utilized, greatly improving the SPL output by the MEMS speaker. The structure proposed in the present invention can convert the bending vibration of the piezoelectric film layer into the up and down vertical vibration of the external hard diaphragm layer, so that the sound waves emitted by the MEMS speaker are purer, reducing THD (harmonic distortion) and the like, thereby improving the comprehensive performance of the MEMS speaker. The manufacturing process of the hard diaphragm layer provided in this embodiment is compatible with the existing MEMS process, and does not require subsequent manual assembly and other operations, so that the consistency and reliability of the MEMS speaker are guaranteed, and it has the advantage of low cost. In summary, the MEMS speaker provided in this embodiment can improve the output performance of the MEMS speaker and reduce the manufacturing cost of the MEMS speaker.

[0041] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 It is a structural schematic diagram of a piezoelectric MEMS speaker in a non-vibration state provided by the related technology;

[0044] Figure 2It is a structural schematic diagram of a piezoelectric MEMS speaker under vibration provided by the related technology;

[0045] Figure 3 yes Figure 1 The simulation result diagram of the structure shown in the vibration condition;

[0046] Figure 4 is a schematic diagram of a top view of a micro-electromechanical system speaker provided according to an embodiment of the present invention;

[0047] Figure 5 is along Figure 4 A schematic diagram of a cross-sectional structure obtained by cutting along the section line A1A2 in FIG.

[0048] Figure 6 is a schematic diagram of a top view structure of a second substrate provided according to an embodiment of the present invention;

[0049] Figure 7 is a schematic diagram of a top view structure of a first electrode provided according to an embodiment of the present invention;

[0050] Figure 8 is a schematic diagram of a top view structure of a piezoelectric film layer provided according to an embodiment of the present invention;

[0051] Fig. 9 is a schematic diagram of a top view structure of a second electrode provided according to an embodiment of the present invention;

[0052] Fig.10 is a schematic diagram of a top view structure of a support layer provided according to an embodiment of the present invention;

[0053] Fig.11 is a schematic structural diagram of a micro-electromechanical system speaker when making sound according to an embodiment of the present invention;

[0054] Fig.12 is a schematic diagram of a top view structure of a hard diaphragm layer provided according to an embodiment of the present invention;

[0055] Fig.13 is a schematic diagram of a top view structure of a hard diaphragm layer provided according to an embodiment of the present invention;

[0056] Fig.14 is a schematic diagram of the longitudinal cross-section structure of the second bending substructure;

[0057] Fig.15 and Fig.16 is a structural schematic diagram of a process for manufacturing a micro-electromechanical system speaker provided in an embodiment of the present invention;

[0058] Fig.17The figure is a schematic diagram of a top view of a micro-electromechanical system speaker provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0060] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0061] This embodiment provides a micro-electromechanical system speaker, which can solve the problems existing in the existing speakers.

[0062] Figure 4 FIG. 1 is a schematic diagram of a top view of a MEMS speaker provided according to an embodiment of the present invention. In order to more clearly understand the positional relationship between the membrane layers in the MEMS speaker provided in this embodiment, Figure 4 The MEMS speaker shown in the figure does not have a hard diaphragm layer 260. Figure 5 is along Figure 4 A schematic diagram of a cross-sectional structure obtained by cutting the section line A1A2 in FIG. Figure 5 The cross-sectional view in includes a hard diaphragm layer 260 . Figure 6 is a schematic diagram of a top view of a second substrate provided according to an embodiment of the present invention, Figure 7 is a schematic diagram of a top view structure of a first electrode provided according to an embodiment of the present invention, Figure 8 is a schematic diagram of a top view structure of a piezoelectric film layer provided according to an embodiment of the present invention, Fig. 9 is a schematic diagram of a top view structure of a second electrode provided according to an embodiment of the present invention, Fig.10 is a schematic diagram of a top view of a support layer provided according to an embodiment of the present invention, with reference to Figure 4-Figure 10 The speaker provided in this embodiment includes: a substrate structure 210, a first electrode 220, a piezoelectric film layer 230, a second electrode 240, a support layer 250 and a hard diaphragm layer 260. The substrate structure 210 includes a first substrate 211 and a second substrate 212 stacked in layers; the first substrate 211 includes a first through hole 201, and the second substrate 212 includes a plurality of first slits 202 (see Figure 6 ), each first slit 202 is connected to the first through hole 201; the first electrode 220 is located on the side of the second substrate 212 away from the first substrate 211, and the first electrode 220 includes a plurality of second slits 203 (refer to Figure 7 ), the second slit 203 is connected to the first slit 202; the piezoelectric film layer 230 is located on the side of the first electrode 220 away from the substrate structure 210, and the piezoelectric film layer 230 includes a plurality of third slits 204 (refer to Figure 8 ), the third slit 204 is connected to the second slit 203; the second electrode 240 is located on the side of the piezoelectric film layer 230 away from the first electrode 220, and the second electrode 240 includes a plurality of second sub-electrodes 241 electrically connected to each other (refer to Fig. 9 ), the gap between two adjacent second sub-electrodes 241 includes a first slit 202, a second slit 203 and a third slit 204; the support layer 250 is located on the side of the piezoelectric film layer 230 away from the first electrode 220, and the support layer 250 includes a support ring 251 and a support column 252 (see Fig.10 ), the support ring 251 is located at the edge of the piezoelectric film layer 230, and the support ring 251 is arranged around the support column 252; the hard diaphragm layer 260 is located on the side of the support layer 250 away from the piezoelectric film layer 230, and the hard diaphragm layer 260 includes a bending structure 261 and a planar structure 262.

[0063] Specifically, the number of the first slits 202, the number of the second slits 203, and the number of the third slits 204 may be equal. For example, the number of the first slits 202 may be 4. The first slits 202 may correspond to the second slits 203 one by one, and each first slit 202 is connected to the corresponding second slit 203. The second slits 203 may correspond to the third slits 204 one by one, and each second slit 203 is connected to the corresponding third slit 204. The shapes of the first slits 202, the shapes of the second slits 203, and the shapes of the third slits 204 may be the same, but the sizes may be different. For example, the shape of the first slits 202 may be rectangular.

[0064] The vertical projection of the first electrode 220 on the second substrate 212, the vertical projection of the piezoelectric film layer 230 on the second substrate 212, and the vertical projection of the second electrode 240 on the second substrate 212 overlap each other. After the first electrode 220 and the second electrode 240 input an electrical signal, the piezoelectric film layer 230 can convert the electrical signal into displacement. In this embodiment, the first slit 202, the second slit 203, and the third slit 204 are connected and located at the gap between two adjacent second sub-electrodes 241, so that the piezoelectric film layer 230 can be separated into several independent smaller piezoelectric film sub-layers, and the constraint of one end of the piezoelectric film layer 230 can be released to obtain a greater degree of freedom, thereby bringing a larger amplitude and SPL.

[0065] Continue to refer Fig. 9 The second electrode 240 further includes a plurality of connecting electrodes 242, and the connecting electrodes 242 are used to electrically connect two adjacent second sub-electrodes 241. The vertical projection of the second electrode 420 on the piezoelectric film layer 230 may not overlap with the vertical projection of the support layer 250 on the piezoelectric film layer 230. The vertical projection of the first electrode 220 on the second substrate 212 overlaps with the vertical projection of the support column 252 on the second substrate 212, and the vertical projection of the piezoelectric film layer 230 on the second substrate 212 overlaps with the vertical projection of the support column 252 on the second substrate 212.

[0066] The material of the support layer 250 may include a polymer. The support layer 250 and the second electrode 240 may be located on the surface of the piezoelectric film layer 230 away from the substrate structure 210. The support ring 251 is distributed around the second electrode 240. The vertical projection of the support column 252 on the piezoelectric film layer 230 covers the center of the piezoelectric film layer 230. The second electrode 240 is not arranged at the center of the piezoelectric film layer 230, and the support column 252 may be located at the center of the piezoelectric film layer 230. The vertical projection of the support column 252 on the piezoelectric film layer 230 includes a plurality of third slits 204. The support column 252 is arranged at the center of the piezoelectric film layer 230, so that the support column 252 can transmit the vibration generated by the piezoelectric film layer 230 to the hard diaphragm layer 260, and the support ring 251 can also transmit the vibration generated by the piezoelectric film layer 230 to the hard diaphragm layer 260. The support layer 250 and the hard diaphragm layer 260 can construct an additional cavity above the piezoelectric film layer 230 of the MEMS speaker.

[0067] The material of the hard diaphragm layer 260 may include polyparaxylene (abbreviated as Parylene). The preparation process of the hard diaphragm layer 260 is compatible with and integrated into the process flow of the micro-electromechanical system speaker. The hard diaphragm layer 260 is formed by the method of subsequent assembly and film pasting. No additional assembly work is required, and it can be compatible with and integrated into the process flow of the micro-electromechanical system speaker, which can effectively reduce costs, improve production efficiency and enhance product consistency. The area of ​​the hard diaphragm layer 260 other than the bending structure 261 can be a plane structure 262. The vertical projection of the bending structure 261 on the substrate structure 210 surrounds the vertical projection of the support column 252 on the substrate structure 210. The thickness of the hard diaphragm layer 260 at the bending structure 261 can be equal to the thickness of the plane structure 262. The bending structure 261 can be located near the edge of the hard diaphragm layer 260, or it can be located inside the hard diaphragm layer 260.

[0068] Fig.11 is a schematic diagram of the structure of a MEMS speaker when emitting sound according to an embodiment of the present invention, with reference to Fig.11 The working principle of the MEMS speaker provided in this embodiment is as follows: after the first electrode 220 and the second electrode 240 input an electrical signal, the piezoelectric film layer 230 converts the electrical signal into displacement, and the piezoelectric film layer 230 acts as a driving device to drive the support layer 250, and finally relies on the vibration of the hard diaphragm layer 260 to produce sound, and can effectively conduct the maximum displacement of the piezoelectric film layer 230 to the hard diaphragm layer 260. In addition, because the harder hard diaphragm layer 260 can better push the air to achieve better sound quality when vibrating and producing sound, the harder diaphragm layer 260 will also bring constraints to the vibrating part of the piezoelectric film layer 230, resulting in the vibration of the piezoelectric film layer 230 being limited, thereby reducing the overall sound pressure output. In the present invention, a bending structure 261 is added to the hard diaphragm layer 260 under the condition of being compatible with the MEMS process, and the additional constraints and burdens on the piezoelectric film layer 230 are reduced without substantially reducing the effective area of ​​the hard diaphragm layer 260, thereby ensuring a larger output SPL of the MEMS speaker.

[0069] It should be noted that Figure 4 The top view of the MEMS speaker shows that the MEMS speaker is in a rectangular shape, but this is not a limitation of the present invention. The MEMS speaker provided in this embodiment may also be in a circular shape or other polygonal shape.

[0070] The present embodiment provides a micro-electromechanical system speaker, which includes a substrate structure, a first electrode, a piezoelectric film layer, a second electrode, a support layer and a hard diaphragm layer. The substrate structure includes a first substrate and a second substrate that are stacked. The first electrode is located on a side of the second substrate away from the first substrate, and the piezoelectric film layer is located on a side of the first electrode away from the substrate structure; the second electrode is located on a side of the piezoelectric film layer away from the first electrode. The support layer is located on a side of the piezoelectric film layer away from the first electrode, and the support layer includes a support ring and a support column, and the support ring is located at the edge of the piezoelectric film layer and surrounds the support column. The hard diaphragm layer is located on a side of the support layer away from the second electrode, and the hard diaphragm layer includes a bending structure and a planar structure, and the vertical projection of the bending structure on the substrate structure surrounds the vertical projection of the support column on the substrate structure. The support layer in this embodiment constructs an additional cavity on one side of the piezoelectric diaphragm layer. The support layer can transmit the maximum center vibration generated by the piezoelectric film layer to the hard diaphragm layer on the top, and the hard diaphragm layer replaces the piezoelectric film layer to vibrate and produce sound. Compared with other structures, the maximum center displacement of the piezoelectric braking structure can be fully utilized, greatly improving the SPL output by the MEMS speaker. The structure proposed in the present invention can convert the bending vibration of the piezoelectric film layer into the up and down vertical vibration of the external hard diaphragm layer, so that the sound waves emitted by the MEMS speaker are purer, reducing THD (harmonic distortion) and the like, thereby improving the comprehensive performance of the MEMS speaker. The manufacturing process of the hard diaphragm layer provided in this embodiment is compatible with the existing MEMS process, and does not require subsequent manual assembly and other operations, so that the consistency and reliability of the MEMS speaker are guaranteed, and it has the advantage of low cost. In summary, the MEMS speaker provided in this embodiment can improve the output performance of the MEMS speaker and reduce the manufacturing cost of the MEMS speaker.

[0071] Optional, Fig.12 is a schematic diagram of a top view of a hard diaphragm layer provided according to an embodiment of the present invention, with reference to Fig.11 and Fig.12 The bending structure includes a first bending substructure 2611 ; the first bending substructure 2611 is adjacent to the support ring 251 and surrounds one side of the support ring 251 close to the support column 252 .

[0072] Specifically, the first bending substructure 2611 may include a plurality of grooves. For example, the first bending substructure 2611 includes three grooves. The longitudinal section of the groove may be any one of a rectangular, a trapezoidal, an inverted trapezoidal, a triangular or an arcuate shape to meet different vibration displacement requirements. The longitudinal section is perpendicular to the plane where the substrate structure 210 is located.

[0073] The first bending substructure 2611 is disposed near the edge of the hard diaphragm layer 260 , which can enable the MEMS speaker to further generate uniform and ideal sound waves.

[0074] Optional, Fig.13 is a schematic diagram of a top view structure of another hard diaphragm layer provided according to an embodiment of the present invention, referring to Fig.11 and Fig.13 The bending structure also includes a plurality of second bending substructures 2612; the vertical projections of the plurality of second bending substructures 2612 on the substrate structure 210 surround the vertical projection of the support column 252 on the substrate structure 210, and the vertical projections of the plurality of second bending substructures 2612 on the substrate structure 210 are distributed in a whirlwind manner.

[0075] Specifically, the vertical projection of the second bending substructure 2612 on the substrate structure 210 is in the shape of a curved surface. Fig.14 is a schematic diagram of the longitudinal section structure of the second bending substructure, refer to Fig.14 The second bending substructure 2612 may also include a plurality of grooves, and the longitudinal cross-section of the groove may be any one of a rectangular, a trapezoidal, an inverted trapezoidal, a triangular or an arcuate shape. The shape and depth of the groove in the first bending substructure 2611 may correspond to and be equal to the shape and depth of the groove in the second bending substructure 2612.

[0076] This embodiment adds various bending shapes to the edge and inside of the hard diaphragm layer 260, which can reduce the additional constraints and burdens on the piezoelectric film layer without substantially reducing the effective area of ​​the hard diaphragm layer 260. The vertical projections of the plurality of second bending substructures 2612 on the substrate structure 210 are arranged in a whirlwind distribution, which can further ensure a larger output SPL of the MEMS speaker.

[0077] Optional, continue to refer to Fig.11 The planar structure includes a first planar substructure 2621 and a second planar substructure 2622; the thickness of the first planar substructure 2621 is the same as the thickness of the second planar substructure 2622; the first planar substructure 2621 is located on the surface of the support layer 250 away from the piezoelectric film layer 230; the first distance d1 is smaller than the second distance d2, wherein the first distance d1 is the distance from the surface of the first planar substructure 2621 away from the substrate structure 210 to the surface of the substrate structure 210 close to the first planar substructure 2621, and the second distance d2 is the distance from the surface of the second planar substructure 2622 away from the substrate structure 210 to the surface of the substrate structure 210 close to the first planar substructure 2621.

[0078] Specifically, the thickness of the first planar substructure 2621 is set to be the same as the thickness of the second planar substructure 2622, and the first planar substructure 2621 and the second planar substructure 2622 can be formed simultaneously by using the same process during the process of manufacturing the hard diaphragm layer 260. The structure other than the first planar substructure 2621 in the planar structure can be the second planar substructure 2622. At least part of the second planar substructure 2622 can be located on the surface of the support layer 250 away from the piezoelectric film layer 230.

[0079] Fig.15 and Fig.16 is a structural diagram of a process for manufacturing a MEMS speaker according to an embodiment of the present invention, with reference to Fig.15 and Fig.16 Before forming the hard diaphragm layer 260, it is necessary to fill the side of the support layer 250 away from the piezoelectric film layer 230 with a sacrificial layer 270, and the sacrificial layer 270 completely covers the support layer 250. Then, the sacrificial layer 270 is etched to expose part of the support layer 250. To ensure the etching Fig.15 The controllability of the process of forming the sacrificial layer 270 shown in the figure will retain the sacrificial layer 270 at the edge of the support layer 250, and then form the hard diaphragm layer 260 on the etched sacrificial layer 270. In this embodiment, the first distance d1 is set to be smaller than the second distance d2, which can ensure the controllability of the process during the process of manufacturing the MEMS speaker.

[0080] It should be noted that Fig.15 The structure shown to Fig.16 The structures shown may include other manufacturing steps to ensure the reliability of the formed hard diaphragm layer 260. During the process of the MEMS speaker, the sacrificial layer 270 is removed to form a cavity in the MEMS speaker.

[0081] Optional, continue to refer to Fig.11 , the bending structure 261 is bent along the thickness direction of the substrate structure 210; the third distance d3 is equal to the second distance d2, wherein the third distance d3 is the maximum distance between the surface of the bending structure 261 away from the substrate structure 210 and the surface of the substrate structure 210 close to the bending structure 261.

[0082] For details, please refer to Fig.16 Before forming the hard diaphragm layer 260, the shape of the bending structure is first etched at the surface of the sacrificial layer 270 away from the substrate structure 210. In this embodiment, the third distance d3 is set equal to the second distance d2, and a groove of the bending structure can be formed at the surface etching of the sacrificial layer 270. There is no need to additionally process the sacrificial layer 270, which reduces the manufacturing steps of the MEMS speaker and further reduces the manufacturing cost of the MEMS speaker.

[0083] Optionally, a vertical projection of the second slit on the second substrate covers the first slit; and a vertical projection of the third slit on the second substrate covers a vertical projection of the second slit on the second substrate.

[0084] Specifically, in the process of manufacturing a MEMS speaker, the third slit may be formed first, and then the first electrode may be etched in the third slit to form the second slit, and then the second substrate may be etched in the second slit to form the first slit. The vertical projection of the second slit on the second substrate is set to cover the first slit; the vertical projection of the third slit on the second substrate covers the vertical projection of the second slit on the second substrate, which can facilitate the manufacturing of the second slit and the first slit.

[0085] In the same direction, the size of the third slit can be greater than or equal to the size of the second slit, and the size of the second slit can be greater than or equal to the size of the first slit. Setting the size of the third slit larger than the size of the second slit can allow a certain distance between the first electrode and the second electrode to avoid short circuit between the first electrode and the second electrode.

[0086] Optionally, the thickness of the support layer ranges from 50 μm to 150 μm.

[0087] Specifically, when the MEMS speaker receives a driving signal, the piezoelectric film layer is deformed and transmitted from the support layer to the hard diaphragm layer. The thickness of the support layer is set to 50μm to 150μm, which can increase the vertical vibration range of the hard diaphragm layer, thereby greatly improving the SPL output by the MEMS speaker.

[0088] Optional, continue to refer to Figure 5 The first substrate 211 includes a first sub-substrate 214 and a second sub-substrate 213; the second sub-substrate 213 is located between the first sub-substrate 214 and the second substrate 212; the first sub-substrate 214 includes a first sub-through hole; the second sub-substrate 213 includes a second sub-through hole; the first sub-through hole and the second sub-through hole are connected to form a first through hole 201.

[0089] Specifically, the substrate structure 210 may be a SOI (Silicon-On-Insulator) substrate. The SOI substrate introduces a buried oxide layer between the top silicon and the back substrate. The buried oxide layer serves as the second sub-substrate 213. The top silicon serves as the second substrate 212. The back substrate serves as the first sub-substrate 214. Using the SOI substrate simplifies the film layer structure of the substrate structure 210 and saves the preparation cost.

[0090] Optional, Fig.17 is a schematic diagram of a top view of a micro-electromechanical system speaker provided according to an embodiment of the present invention, with reference to Fig.17The MEMS speaker further includes an exposed first pad 280 and a second pad 290 , wherein the first pad 280 is electrically connected to the first electrode, and the second pad 290 is electrically connected to the second electrode.

[0091] Specifically, the first pad 280 and the second pad 290 may be electrically connected to an external device, and may transmit an electrical signal transmitted by the external device to the first electrode and the second electrode.

[0092] This embodiment also provides an electronic device, which includes the speaker provided by any embodiment of the present invention.

[0093] Specifically, the electronic device provided in this embodiment can be a mobile phone, a tablet computer, a laptop computer, a camera, a personal computer, a laptop computer, a vehicle-mounted device, a wearable device, augmented reality (AR) glasses, AR helmets, virtual reality (VR) glasses, VR helmets, fixed-line handsets (pickups), medical auxiliary equipment (such as hearing aids), various headphones (such as wireless headphones or wired headphones), and other devices with speakers.

[0094] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0095] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A micro-electromechanical system speaker, characterized in that: include: A substrate structure, wherein the substrate structure comprises a first substrate and a second substrate which are stacked; the first substrate comprises a first through hole, the second substrate comprises a plurality of first slits, and each of the first slits is connected to the first through hole; A first electrode is located on a side of the second substrate away from the first substrate, the first electrode comprises a plurality of second slits, and the second slits are connected to the first slits; a piezoelectric film layer, located on a side of the first electrode away from the substrate structure, the piezoelectric film layer comprising a plurality of third slits, the third slits being connected to the second slits; A second electrode is located at a side of the piezoelectric film layer away from the first electrode, the second electrode comprises a plurality of second sub-electrodes electrically connected to each other, and a gap between two adjacent second sub-electrodes comprises the first slit, the second slit and the third slit; A support layer, located on a side of the piezoelectric film layer away from the first electrode, wherein the support layer comprises a support ring and a support column, the support ring is located at the edge of the piezoelectric film layer, and the support ring is arranged around the support column; The hard diaphragm layer is located on a side of the support layer away from the piezoelectric film layer, and the hard diaphragm layer includes a bending structure and a planar structure.

2. The MEMS speaker according to claim 1, characterized in that: The bending structure includes a first bending substructure; The first bending substructure is adjacent to the supporting ring and surrounds one side of the supporting ring close to the supporting column.

3. The MEMS speaker according to claim 2, characterized in that: The bending structure further includes a plurality of second bending substructures; The vertical projections of the plurality of second bending substructures on the substrate structure surround the vertical projection of the support column on the substrate structure, and the vertical projections of the plurality of second bending substructures on the substrate structure are distributed in a whirlwind manner.

4. The MEMS speaker according to claim 1, characterized in that: The planar structure includes a first planar substructure and a second planar substructure; The thickness of the first planar substructure is the same as the thickness of the second planar substructure; The first planar substructure is located on a surface of the support layer away from the piezoelectric film layer; The first distance is smaller than the second distance, wherein the first distance is the distance between the surface of the first planar substructure away from the substrate structure and the surface of the substrate structure close to the first planar substructure, and the second distance is the distance between the surface of the second planar substructure away from the substrate structure and the surface of the substrate structure close to the first planar substructure.

5. The MEMS speaker according to claim 4, characterized in that: The bending structure is bent along the thickness direction of the substrate structure; The third distance is equal to the second distance, wherein the third distance is the maximum distance between a surface of the bending structure away from the substrate structure and a surface of the substrate structure close to the bending structure.

6. The MEMS speaker according to claim 1, characterized in that: The vertical projection of the second slit on the second substrate covers the first slit; A vertical projection of the third slit on the second substrate covers a vertical projection of the second slit on the second substrate.

7. The MEMS speaker according to claim 1, characterized in that: The thickness of the support layer ranges from 50 μm to 150 μm.

8. The MEMS speaker according to claim 1, characterized in that: The first substrate includes a first sub-substrate and a second sub-substrate; The second sub-substrate is located between the first sub-substrate and the second substrate; The first sub-substrate includes a first sub-via; The second sub-substrate includes a second sub-through hole; The first sub-through hole is connected to the second sub-through hole to form the first through hole.

9. The MEMS speaker according to claim 1, characterized in that: Also included are an exposed first solder pad and a second solder pad; The first pad is electrically connected to the first electrode, and the second pad is electrically connected to the second electrode.

10. An electronic device, characterized in that: A micro-electromechanical system speaker comprising any one of claims 1-9.

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