Loudspeaker unit, preparation method thereof and electronic equipment

Abstract

The invention provides a loudspeaker unit, a preparation method thereof and electronic equipment, and relates to the technical field of piezoelectric devices, the loudspeaker unit comprises a base layer, a vibrating diaphragm layer and an organic film, the base layer is of a frame structure, and a first through hole is formed in the thickness direction of the base layer; the vibrating diaphragm layer is located on one side of the base layer in the thickness direction and comprises at least one vibrating diaphragm, a second through hole is formed between the vibrating diaphragm and the base layer and / or between two adjacent vibrating diaphragms, at least part of the edge of the vibrating diaphragm is fixedly connected with the base layer to form a cantilever structure, the vibrating diaphragm covers part of the first through hole, and the second through hole is communicated with the first through hole; and the organic film covers the vibrating diaphragm layer, the organic film comprises a first film area, the first film area covers the second through hole, a thinning structure is arranged on the first film area, and the thinning structure is used for reducing the Young modulus of the first film area, so that the organic film can be driven by the vibrating diaphragm to move more easily and drive air to vibrate to the maximum extent, and the sound pressure is maximized.

Description

Loudspeaker unit, manufacturing method thereof, and electronic device Technical Field

[0001] The present application relates to the technical field of piezoelectric devices, and in particular to a speaker unit, a preparation method thereof, and an electronic device. Background Art

[0002] With the advancement of information and communication technology and electronic devices, mobile communication devices such as smartphones are becoming increasingly popular. Many of these devices have audio functionality to enable remote voice communication, such as voice transmission and voice interaction. With technological advancements, various electronic devices are becoming increasingly miniaturized, integrating multiple functions into small electronic devices. Currently, smartphones and most other small electronic devices have built-in speakers, which are now standard features in ultra-compact audio devices such as headphones and hearing aids.

[0003] According to the sound-generating principle of the speaker, it can be mainly divided into three types: electromagnetic, piezoelectric and electrostatic. Among them, the piezoelectric speaker is a commonly used speaker module, which is mainly manufactured based on the principle that piezoelectric materials are deformed by the action of an electric field. Specifically, a diaphragm including a piezoelectric element is placed in an electric field formed by an audio current signal, and the inverse piezoelectric effect of the piezoelectric element is used to drive the diaphragm to make a sound. At present, due to the limitations of the piezoelectric ceramic sintering process, the device size cannot be reduced, and under the limitation of the same spatial size, the power of the speaker cannot be further increased, resulting in insufficient sound pressure. In some piezoelectric units with organic films, the organic film needs to have a certain thickness to ensure that the organic film has corresponding structural strength. However, thicker organic films have a larger Young's modulus, especially in the direction of the extension surface of the organic film, which is difficult to stretch, making it difficult for the organic film to vibrate under the drive of the diaphragm, and unable to maximize the drive of air vibration to generate sound pressure.

[0004] Summary of the Invention

[0005] The present application provides a speaker unit, a preparation method thereof, and an electronic device. By designing a thinning structure on an organic film, the Young's modulus of the organic film can be reduced, so that the organic film can vibrate more easily and move under the drive of the diaphragm, thereby maximizing the vibration of the air and thus maximizing the sound pressure.

[0006] In the first aspect, the present application provides a speaker unit comprising: a base layer, a diaphragm layer and an organic film, wherein the base layer is in a frame structure and is provided with first through holes that are interconnected in the thickness direction; the diaphragm layer is located on one side of the base layer along the thickness direction, comprising at least one diaphragm, a second through hole being provided between the diaphragm and the base layer and / or between two adjacent diaphragms, at least part of the edge of the diaphragm is fixedly connected to the base layer to form a cantilever structure, the diaphragm covers part of the first through hole, and the second through hole is interconnected with the first through hole; the organic film covers the diaphragm layer, the organic film comprises a first membrane area, the first membrane area covers the second through hole, a thinning structure is provided on the first membrane area, and the thinning structure is used to reduce the Young's modulus of the first membrane area.

[0007] In this application, by providing a diaphragm actuation structure, the speaker unit has a cantilever structure, which can increase the output power of the speaker unit. By providing an organic membrane that closes the first through hole, the sound pressure is prevented from decreasing without affecting the diaphragm actuation. More importantly, multiple thinning structures are provided on the organic membrane between the cantilevers to reduce the Young's modulus of the organic membrane, allowing the organic membrane to vibrate more easily under the drive of the diaphragm, thereby maximizing the vibration of the air and thus maximizing the sound pressure. Therefore, the above structural design is conducive to minimizing the size of the speaker unit and maximizing the sound pressure within a limited space.

[0008] In one possible implementation, the thinning structure includes a third through hole and / or a first groove located on the first film region. Designing the thinning structure as a through hole and / or groove can reduce the thickness of the organic film and can be obtained by etching, simplifying the preparation process.

[0009] In one possible implementation, the opening of the third through hole and / or the first groove is longer in a first direction than in a second direction, the first direction and the second direction are both parallel to the extension surface of the first membrane region, and the first direction and the second direction are perpendicular. The third through hole and / or the first groove are designed as a slit shape, which facilitates the vibration of the organic film driven by the diaphragm.

[0010] In one possible implementation, the length of the opening of the third through hole and / or the first groove in the first direction is less than 500 microns; and / or the length of the third through hole in the second direction is less than 5 microns. By defining the specific shape of the third through hole and / or the first groove, air passing through the third through hole and / or the first groove can be minimized, suppressing the drop in sound pressure caused by air escape.

[0011] In one possible implementation, the ratio of the thickness of the organic film to the length of the third through hole and / or the first groove in the second direction is in a range of 1 / 700 to 1 / 140. By limiting the thickness of the organic film, the speaker unit can have a greater sound pressure.

[0012] In one possible implementation, the base layer includes a frame having the first through hole extending in a thickness direction therein; the diaphragm extends from the frame into the first through hole in a third direction; and the ratio of the minimum width of the first diaphragm region along the third direction to the minimum width of the base layer along the third direction is in a range of 1 / 10 to 9 / 10. The size of the first diaphragm region is designed to maximize the sound pressure of the speaker unit.

[0013] In a possible implementation, the first film region is fixedly connected to the base layer. Fixedly connecting the first film region of the organic film to the base layer enables the organic film to cover the base layer, thereby preventing a reduction in sound pressure.

[0014] In one possible implementation, the opening of the third through hole and / or the first groove includes at least one of a rectangular, diamond-shaped, elliptical, and waist-shaped hole shape. The opening of the third through hole and / or the first groove can have a variety of shapes and can be freely designed based on actual needs. It only needs to be a narrow slit, thereby forming a structure that allows the organic film to vibrate more easily.

[0015] In a possible implementation, there are multiple diaphragms, the multiple diaphragms are separated, and at least a portion of the second through hole is located between two adjacent diaphragms. The actuation performance of the diaphragms can be improved by designing multiple diaphragms.

[0016] In one possible implementation, the diaphragm includes a first diaphragm and a second diaphragm disposed opposite each other, the first diaphragm having a first edge on a side proximal to the second diaphragm, the second diaphragm having a second edge on a side proximal to the first diaphragm, and the second through-hole being spaced between the first edge and the second edge. The opposing dual-diaphragm actuation structure provides the speaker unit with a dual cantilever structure that is opposed to each other and spaced apart, thereby improving the actuation performance of the speaker unit and increasing the output power of the speaker unit.

[0017] In one possible implementation, at least a portion of the first edge and at least a portion of the second edge are parallel to each other, resulting in a symmetrical arrangement of the first and second diaphragms. This facilitates consistent actuation of the first and second diaphragms, thereby improving the actuation performance of the diaphragms and ensuring the sound quality of the speaker unit.

[0018] In one possible implementation, within the region where the first edge and the second edge are parallel, the length of the opening of the third through hole and / or the first groove in a direction parallel to the first edge is greater than the length in a direction perpendicular to the first edge. The third through hole and / or the first groove are slit-shaped, providing high viscous resistance, which not only facilitates movement of the organic membrane but also prevents sound leakage from the speaker unit, thereby maximizing sound pressure.

[0019] In one possible implementation, the base layer includes a frame having the first through hole extending in a thickness direction therein. The diaphragm extends from the frame into the first through hole in a third direction, and the diaphragm gradually decreases in width along the third direction. By defining the shape of the diaphragm, the actuation performance of the diaphragm is improved.

[0020] In a possible implementation, the diaphragm has a trapezoidal structure. By defining the shape of the diaphragm more specifically, it is helpful to further improve the actuation performance of the diaphragm.

[0021] In one possible implementation, the organic film is made of polyimide, and the diaphragm is made of a single-crystal piezoelectric ceramic material. The Young's modulus of the polyimide material is relatively low, and an organic film with uniform thickness can be prepared. In addition, the organic film prepared from polyimide has good processability, and it is easy to use a photolithography process to set a thinning structure thereon, and it is compatible with the micro-electromechanical system process during the preparation of the speaker unit. The use of a single-crystal piezoelectric ceramic material to prepare the diaphragm can reduce the power consumption of the speaker unit and achieve long-lasting performance.

[0022] In a second aspect, the present application provides a method for preparing a speaker unit, for preparing any of the above-mentioned speaker units, comprising the following steps:

[0023] Sequentially forming a first electrode layer, a vibration layer, and a second electrode layer on a substrate to form a first matrix;

[0024] forming a second groove on the first base, the second groove sequentially penetrating the second electrode layer, the vibration layer, and the first electrode layer to separate the vibration layer into a cantilever structure, and the bottom surface of the second groove is a part of the substrate to form a second base;

[0025] covering the second substrate with a passivation layer;

[0026] preparing a metal pattern layer on the passivation layer, wherein at least a portion of the metal pattern layer passes through the passivation layer and is electrically connected to the second electrode layer to form a third substrate;

[0027] covering the third substrate with an organic film, wherein the organic film covers the diaphragm and the inner wall of the second groove;

[0028] A third through hole or a first groove is formed on a portion of the organic film located at the bottom of the first groove.

[0029] The above method can easily control the shape of the speaker unit and realize ultra-miniaturization of the speaker unit.

[0030] In a third aspect, the present application provides an electronic device comprising a controller and any of the above-described speaker units, wherein the controller and the speaker unit are electrically connected to drive the diaphragm layer in the speaker unit to vibrate. The electronic device of the present application can achieve both miniaturization and increased output power, and can meet the performance requirements of active noise reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic structural diagram of a true wireless headset provided in an embodiment of the present application;

[0032] FIG2 is a cross-sectional view of the true wireless headset in FIG1 provided by this application;

[0033] FIG3 is a three-dimensional schematic diagram of a speaker unit provided in an embodiment of the present application;

[0034] FIG4 is an exploded view of the structure of the speaker unit in FIG3 provided by this application;

[0035] FIG5 is a partial cross-sectional schematic diagram of the structure of the speaker unit in FIG3 provided by the present application;

[0036] FIG6 is a three-dimensional schematic diagram of the diaphragm and substrate of the speaker unit in FIG3 provided by the present application;

[0037] FIG7 is a schematic structural diagram of an organic film of a speaker unit provided in an embodiment of the present application;

[0038] FIG8 is a schematic structural diagram of a diaphragm layer provided in an embodiment of the present application;

[0039] FIG9 is a schematic structural diagram of two diaphragms provided on a diaphragm layer according to an embodiment of the present application;

[0040] FIG10 is a schematic diagram of a structure in which three diaphragms are provided on a diaphragm layer according to an embodiment of the present application;

[0041] FIG11 is a schematic structural diagram of four diaphragms provided on a diaphragm layer according to an embodiment of the present application;

[0042] FIG12 is a schematic structural diagram of an organic film provided in an embodiment of the present application;

[0043] FIG13 is a schematic structural diagram of an organic film when a diaphragm is provided on a diaphragm layer according to an embodiment of the present application;

[0044] FIG14 is a schematic diagram of the structure of an organic film when two diaphragms are provided on a diaphragm layer according to an embodiment of the present application;

[0045] FIG15 is a schematic diagram of the structure of an organic film when three diaphragms are provided on a diaphragm layer according to an embodiment of the present application;

[0046] FIG16 is a schematic diagram of the structure of an organic film when four diaphragms are provided on a diaphragm layer according to an embodiment of the present application;

[0047] FIG17 is a schematic top view of a partial structure of a speaker unit provided in an embodiment of the present application;

[0048] FIG18 is a flow chart of a method for preparing a speaker unit according to an embodiment of the present application;

[0049] FIG19 is a structural diagram of the speaker unit preparation process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0051] For ease of understanding, the English abbreviations and related technical terms involved in the embodiments of this application are explained and described below.

[0052] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0053] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0054] It should be understood that the term "and / or" as used herein is simply a term used to describe the existence of three possible relationships between related objects. For example, "A and / or B" can represent the existence of A alone, the existence of both A and B, and the existence of B alone. Furthermore, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0055] It should be understood that the terms “first”, “second”, etc. used in this application are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.

[0056] In the description of this application, the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting this application.

[0057] When used in this application, "within the range of...", unless it is specifically stated that the end value is not included, it is assumed that both end values ​​of the range are included. For example, in the range of 1 to 5, the two values ​​1 and 5 are included.

[0058] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect" and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection or an integrated connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0059] In this application, unless otherwise specified, "thickness direction" refers to the thickness direction of the speaker unit according to this application. The speaker units in this application are mostly plate-shaped. The plate-shaped speaker unit can be formed by stacking a substrate, a piezoelectric layer and an electrode layer. The thickness direction is the direction perpendicular to the plane where the plate structure is located, such as the Z direction in Figure 3.

[0060] This application provides an electronic device. The electronic device in this application may include headphones (such as wired headphones, true wireless headphones, and neckband headphones) and hearing aids. This application uses true wireless headphones as an example to illustrate the electronic device of this application.

[0061] Please refer to Figures 1 and 2. Figure 1 is a structural schematic diagram of a true wireless headset 100 according to an embodiment of the present application, and Figure 2 is a cross-sectional view of the true wireless headset 100 shown in Figure 1. The true wireless headset 100 includes a speaker unit 10, a housing 20 and a controller (not shown in the figure). The housing 20 may include a first shell 210 and a second shell 220. The first shell 210 and the second shell 220 are arranged opposite to each other to form an inner cavity of the headset, and the speaker unit 10 is integrated in the inner cavity of the headset. The speaker unit 10 is arranged in the inner cavity of the headset and divides the inner cavity of the headset into a front cavity 230 and a rear cavity 240. The speaker unit 10 is provided with a front sound hole 250 and a rear sound hole 260, wherein the front sound hole 250 is connected to the front cavity 230, and the rear sound hole 260 is connected to the rear cavity 240, thereby forming the front sound channel and the rear sound channel of the true wireless headset 100. The speaker unit 10 is electrically connected to the controller. When the speaker unit 10 receives an electrical signal, the controller drives the speaker unit 10 to vibrate and converts the electrical signal into a sound signal, thereby playing the sound and transmitting the sound to the user's ears.

[0062] With the development of information and communication technology and electronic devices, electronic devices such as headphones are trending towards miniaturization and portability. The speaker unit 10 built into the electronic device must not only evolve towards miniaturization, but also ensure that the acoustic performance of the speaker unit 10, such as sound pressure level or wider bandwidth, meets user needs.

[0063] A loudspeaker is a commonly used electroacoustic transducer. There are many types of speakers, which can be categorized by their sound-producing principles into electrodynamic speakers (i.e., dynamic coil speakers), electrostatic speakers (i.e., capacitive speakers), electromagnetic speakers (i.e., reed speakers), and piezoelectric speakers (i.e., crystal speakers).

[0064] Currently, piezoelectric speakers are a commonly used type of speaker, manufactured using the principle that piezoelectric materials deform when exposed to an electric field. Specifically, a diaphragm containing a piezoelectric element is placed in an electric field generated by an audio current signal. The inverse piezoelectric effect of the piezoelectric element is used to drive the diaphragm to produce sound. The "piezoelectric effect" refers to the phenomenon in which a dielectric (such as crystals such as quartz and potassium sodium tartrate) polarizes under pressure, creating a potential difference between its two surfaces. The "inverse piezoelectric effect" is the reverse of the "piezoelectric effect," whereby a dielectric placed in an electric field undergoes elastic deformation. Currently, due to limitations in the sintering process for piezoelectric ceramics, device size cannot be reduced. Within the same spatial constraints, the speaker power cannot be further increased, resulting in insufficient sound pressure. In some piezoelectric units with an organic film, the organic film must have a certain thickness to ensure sufficient structural strength. However, a thicker organic film results in a larger Young's modulus, making it difficult for the diaphragm to generate high-frequency or high-amplitude vibrations, thereby failing to maximize the vibration of the air and generate sound pressure. Young's modulus is a physical quantity that describes a solid material's ability to resist deformation. A higher Young's modulus indicates a less susceptible material to deformation. Existing piezoelectric speaker modules suffer from reduced output power when miniaturized, resulting in insufficient sound pressure and impacting the voice functionality of electronic devices. Consequently, there is an urgent need for speakers that can achieve both miniaturization and sufficient sound pressure.

[0065] In order to solve the above problems, the present application provides a speaker unit, refer to Figures 3 to 7, Figure 3 shows a three-dimensional schematic diagram of the speaker unit in this embodiment, Figure 4 shows a structural explosion diagram of the speaker unit in Figure 3, Figure 5 shows a partial cross-sectional schematic diagram of the structure of the speaker unit in Figure 3, Figure 6 shows a three-dimensional schematic diagram of the diaphragm and base layer of the speaker unit in Figure 3, and Figure 7 shows a structural schematic diagram of the organic membrane of the speaker unit in this embodiment.

[0066] The present application provides a speaker unit 10. Referring to Figures 3 and 4 , the speaker unit 10 is constructed by stacking multiple layers in its thickness direction (the Z direction in Figure 3 ), including a circuit substrate 110, a base layer 120, a diaphragm layer 130, and an organic film 140. The base layer 120, the diaphragm layer 130, and the organic film 140 can be grown and formed sequentially on the circuit substrate 110, forming the circuit substrate 110, the base layer 120, the diaphragm layer 130, and the organic film 140 stacked sequentially in the thickness direction.

[0067] As shown in FIG5 , a base layer 120 is fixed to a circuit substrate 110. Base layer 120 is provided with first through-holes 121 extending through the thickness of the base layer 120. First through-holes 121 are located in the middle of the base layer 120, forming a U-shaped structure. A frame structure surrounding first through-holes 121 is fixed to the circuit substrate 110. Circuit substrate 110 is provided with fourth through-holes 111 extending through the thickness of the circuit substrate 110. Fourth through-holes 111 are located in the middle of the circuit substrate 110, forming a U-shaped structure.

[0068] The fourth through hole 111 and the first through hole 121 are connected in the thickness direction. The first outer wall surface 1211 of the first through hole 121 (the inner wall surface of the middle cavity of the base layer 120) and the second outer wall surface 1111 of the fourth through hole 111 (the inner wall surface of the middle cavity of the circuit substrate 110) can be flush with each other, and the first outer wall surface 1211 and the second outer wall surface 1111 can be coplanar along the Z direction. Alternatively, the first outer wall surface 1211 and the second outer wall surface 1111 can be non-coplanar along the Z direction, so that the base layer 120 and the circuit substrate 110 form a step structure at the connection. The width H1 of one side of the circuit substrate 110 along the X direction is greater than or equal to the width H2 of one side of the base layer 120 along the X direction, so that the circuit substrate 110 can better support the base layer 120, as well as support the diaphragm layer 130 and the organic film 140 set on the base layer 120.

[0069] In one embodiment, the width of the circuit substrate 110 along one side in the X direction is greater than or equal to the width of the base layer 120 along one side in the X direction. At the same time, the width of the circuit substrate 110 along the X direction is greater than or equal to the width of the base layer 120 along the X direction. Alternatively, the width of one of the two sides of the circuit substrate 110 along the X direction, both in the one side and in the opposite direction, is greater than or equal to the width of the base layer 120 along the X direction. This allows the circuit substrate 110 to provide better support for the base layer 120.

[0070] In one embodiment, the width of the side edge of the circuit substrate 110 along the Y direction is greater than or equal to the width of the side edge of the base layer 120 along the Y direction. At the same time, the width of the side edge of the circuit substrate 110 along the Y direction is greater than or equal to the width of the side edge of the base layer 120 along the Y direction. Alternatively, the width of one of the two sides of the circuit substrate 110 along the Y direction, on one side and on the other side, is greater than or equal to the width of the side edge of the base layer 120 on the same side, so that the circuit substrate 110 provides better support for the base layer 120.

[0071] It should be noted that the dotted lines in FIG. 5 are only used to illustrate the positions of the first through hole 121 and the fourth through hole 111 to better illustrate the structure of the circuit substrate 110 and the base layer 120 , and do not make any specific or special limitation on the structure of the speaker unit 10 .

[0072] Referring to Figures 4 and 6, a diaphragm layer 130 is provided on the base layer 120. The diaphragm layer 130 is provided on the base layer 120 of the "U"-shaped structure and is located on one side of the base layer 120 along the thickness direction. The diaphragm layer 130 includes a diaphragm 131. At least part of the edge of the diaphragm 131 is fixedly connected to the base layer 120 to form a cantilever structure 1311. The diaphragm 131 includes a fixed portion 131a and a suspended portion 131b. At least part of the edge of the fixed portion 131a of the diaphragm 131 is fixedly connected to the base layer 120, and the suspended portion 131b of the diaphragm 131 is suspended on the inner side of the base layer 120 and extends from the frame of the "U"-shaped structure of the base layer 120 toward one side of the second through hole 132, thereby forming a cantilever structure 1311. The diaphragm layer 130 includes at least one diaphragm 131. For example, the diaphragm layer 130 may include two diaphragms 131, namely a first diaphragm 1312 and a second diaphragm 1313 (FIG. 6). The diaphragm 131 partially covers the first through hole 121, that is, at least a portion of the diaphragm 131 is projected along the thickness direction and overlaps with the first through hole 121.

[0073] A second through hole 132 is provided between the diaphragm 131 and the base layer 120, as well as between adjacent diaphragms 131. The second through hole 132 and the first through hole 121 intersect each other, and the second through hole 132 is located on one side of the first through hole 121 along the positive direction of the Y direction. Referring to FIG6 , the diaphragm 131 includes a first diaphragm 1312 and a second diaphragm 1313 disposed opposite each other on the base layer 120. The first diaphragm 1312 and the second diaphragm 1313 can both be isosceles trapezoids. The longer base sides of the isosceles trapezoids of the first diaphragm 1312 and the second diaphragm 1313 are fixedly connected to the frame structure of the base layer 120, and the shorter base sides of the isosceles trapezoids of the first diaphragm 1312 and the second diaphragm 1313 are parallel to and opposite each other. The first diaphragm 1312 has a first edge 1316 on a side close to the second diaphragm 1313 , and the second diaphragm 1313 has a second edge 1317 on a side close to the first diaphragm 1312 . The second through hole 132 is spaced between the first edge 1316 and the second edge 1317 .

[0074] In one embodiment, a second through hole 132 is provided between the diaphragm 131 and the base layer 120 . It is understandable that when the diaphragm layer 130 includes a diaphragm 131 , the second through hole 132 is formed by a portion of the edge of the diaphragm 131 and the base layer 120 .

[0075] The diaphragm layer 130 deforms under the influence of a driving voltage, and the cantilever structure 1311 of the diaphragm layer 130 drives the diaphragm 131 to vibrate, thereby producing sound. By providing a diaphragm actuation structure, the speaker unit 10 has a cantilever structure. Since one end of the cantilever structure 1311 is suspended in the air, it improves the actuation performance of the speaker unit 10 and can increase the output power of the speaker unit 10.

[0076] It should be noted that the shape of the diaphragm 131 in Figures 3 to 8 of the present application is only an example and does not specifically limit the shape of the diaphragm in the present application.

[0077] As shown in Figures 3 and 7 , the organic film 140 is disposed on and covers the diaphragm layer 130. The organic film 140 is disposed along the thickness direction on one side of the diaphragm layer 130 along the Z direction and is fixedly connected to the diaphragm layer 130. The organic film 140 completely blocks the first through-hole 121, meaning that the projection of the organic film 140 along the thickness direction completely covers the first through-hole 121. By completely blocking the first through-hole 121, the organic film 140 can prevent a reduction in sound pressure without affecting the actuation of the diaphragm 131.

[0078] The organic film 140 includes a first membrane area 141. The projection of the first membrane area 141 along the thickness direction covers the second through hole 132. Part of the edge of the first membrane area 141 is fixedly connected to the base layer 120. The projection of the second membrane area 142 along the thickness direction covers the diaphragm 131, and can be fixedly connected to the diaphragm 131 so that the second membrane area 142 can vibrate synchronously with the diaphragm 131. A thinning structure is provided on the first membrane area 141, and the thinning structure is located on a local area of ​​the first membrane area 141. It can be understood that the thinning structure can thin a part of the first membrane area 141 instead of the entire area. Therefore, the thickness of the organic film 140 in the area where the thinning structure is provided is correspondingly reduced, so that the Young's modulus of the organic film 140 is reduced, and it can vibrate better under the drive of the diaphragm 131, and further drive the air to vibrate and generate a greater sound pressure.

[0079] The speaker unit 10 provided in this embodiment, on the one hand, by providing a diaphragm actuation structure, makes the speaker unit 10 have a cantilever structure, which can improve the output power of the speaker unit 10; on the other hand, by providing an organic membrane 140 that closes the first through hole 121, the sound pressure is prevented from decreasing without affecting the actuation action of the diaphragm 131. More importantly, multiple thinning structures are provided on the organic membrane 140 between the cantilevers to reduce the Young's modulus of the organic membrane 140, so that the organic membrane 140 can move more easily under the drive of the first diaphragm 1312 and the second diaphragm 1313, thereby maximizing the air vibration, generating sound pressure while limiting sound leakage to a minimum, thereby maximizing the sound pressure. Therefore, the above structural design is conducive to minimizing the size of the speaker unit 10 and maximizing the sound pressure within a limited space. Therefore, the speaker unit 10 of the present application can take into account both miniaturization and increased output power, and can meet the performance requirements of active noise reduction.

[0080] In one embodiment, a single diaphragm 131 may be provided on the diaphragm layer 130, or a plurality of diaphragms 131 may be provided. The plurality of diaphragms 131 are separated from each other, and at least a portion of the second through hole 132 is located between two adjacent diaphragms 131. Figures 8 to 11 are schematic diagrams of structures with different numbers of diaphragms provided on the diaphragm layer.

[0081] Please refer to FIG5 and FIG8 . FIG8 shows a diaphragm 131 disposed on the diaphragm layer 130. The diaphragm 131 includes a first diaphragm 1312. Part of the edge of the first diaphragm 1312 and the base layer 120 together enclose a second through hole 132. The second through hole 132 and the first through hole 121 are interconnected.

[0082] In one possible embodiment, FIG9 shows a case where two diaphragms 131 are provided on the diaphragm layer 130. The diaphragms 131 include a first diaphragm 1312 and a second diaphragm 1313 disposed opposite each other. The first diaphragm 1312 and the second diaphragm 1313 are both formed into isosceles trapezoids, such that the first diaphragm 1312 is formed so that its width gradually decreases as it extends toward the second diaphragm 1313, and the second diaphragm 1313 is formed so that its width gradually decreases as it extends toward the first diaphragm 1312. It should be noted that this embodiment only takes the diaphragm 131 in a trapezoidal shape as an example. On the basis of being able to form a cantilever structure, the specific shape of the diaphragm 131 is not limited. It is understood that the longer base sides of the isosceles trapezoids of the first diaphragm 1312 and the second diaphragm 1313 are connected to the frame structure of the base layer 120, and the shorter base sides of the isosceles trapezoids of the first diaphragm 1312 and the second diaphragm 1313 are parallel to and opposite to each other. The first diaphragm 1312 has a first edge 1316 on a side close to the second diaphragm 1313 , and the second diaphragm 1313 has a second edge 1317 on a side close to the first diaphragm 1312 . The second through hole 132 is spaced between the first edge 1316 and the second edge 1317 .

[0083] In one possible embodiment, FIG10 shows a case where three diaphragms 131 are provided on the diaphragm layer 130. The diaphragms 131 include a first diaphragm 1312, a second diaphragm 1313, and a third diaphragm 1314. The first diaphragm 1312 and the second diaphragm 1313 intersect along the extension direction of the third direction D3, and the second diaphragm 1313 and the third diaphragm 1314 intersect along the extension direction of the third direction D3. The third direction D3 refers to, as shown in FIG5, the base layer 120 having a structure similar to a "U" shape, wherein the frame of the "U" shape has a first through hole 121 extending in the thickness direction, and the direction in which the diaphragm 131 extends from the frame into the first through hole 121 is the third direction D3. Exemplarily, the first diaphragm 1312 is fixed to one side of the frame of the base layer 120, the second diaphragm 1313 is fixed to the side of the frame of the base layer 120 opposite the first diaphragm 1312, and the third diaphragm 1314 is fixed to the side of the frame of the base layer 120 adjacent to the first diaphragm 1312. The extension direction of the second diaphragm 1313 along the third direction D3 is perpendicular to the extension direction of the third diaphragm 1314 along the third direction D3. The first diaphragm 1312 has a first edge 1316 on a side close to the second diaphragm 1313, the second diaphragm 1313 has a second edge 1317 on a side close to the first diaphragm 1312, and the third diaphragm 1314 has a third edge 1318 on a side close to the first diaphragm 1312 and the second diaphragm 1313. The second through hole 132 is spaced between the first edge 1316, the second edge 1317, and the third edge 1318.

[0084] In one possible embodiment, FIG11 shows a case where four diaphragms 131 are provided on the diaphragm layer 130. The diaphragms 131 include a first diaphragm 1312, a second diaphragm 1313, a third diaphragm 1314, and a fourth diaphragm 1315. The first diaphragm 1312, the second diaphragm 1313, the third diaphragm 1314, and the fourth diaphragm 1315 are provided along the four frame structures of the "U"-shaped structure of the base layer 120. The first diaphragm 1312 has a first edge 1316 on the side close to the second diaphragm 1313, the second diaphragm 1313 has a second edge 1317 on the side close to the first diaphragm 1312, the third diaphragm 1314 has a third edge 1318 on the side close to the first diaphragm 1312 and the second diaphragm 1313, and the fourth diaphragm 1315 has a fourth edge 1319 on the side close to the first diaphragm 1312 and the second diaphragm 1313. Second through holes 132 are spaced between the first edge 1316 , the second edge 1317 , the third edge 1318 and the fourth edge 1319 .

[0085] This application does not limit the number and arrangement of the multiple diaphragms 131. Those skilled in the art can design the positions of the multiple diaphragms 131 according to actual needs. The number and arrangement of the multiple diaphragms 131 in Figures 8 to 11 are only examples and are not limited in this application.

[0086] In some possible implementations, the shape of the diaphragm 131 may include, but is not limited to, a trapezoid, a triangle, a polygon, and an arc, etc., which is not limited in this application. Those skilled in the art can design the shape of the diaphragm 131 according to actual needs.

[0087] In one embodiment, the diaphragm 131 can be made of a single-crystal piezoelectric ceramic material. For example, the single-crystal piezoelectric ceramic material can be a lead zirconate titanate-based piezoelectric ceramic material. The dielectric constant of a single-crystal piezoelectric ceramic material can be less than 500, while the dielectric constant of an ordinary polycrystalline piezoelectric ceramic material is about 1500. By making the diaphragm 131 of the speaker unit 10 according to the present application include a single-crystal piezoelectric ceramic material with a lower dielectric constant, the overall input capacitance of the speaker unit 10 can be controlled to be less than 30nF@20kHz, thereby reducing the power consumption of the speaker unit 10 and achieving long-lasting performance.

[0088] The organic film 140 is disposed on the diaphragm layer 130 and completely covers it. Referring to FIG. 12 , the ratio of the thickness of the organic film 140 to the length of the third through hole 1411 in the second direction D2 is in the range of 1 / 700 to 1 / 140. The ratio of the minimum width A1 of the first film region 141 along the third direction D3 to the minimum width A2 of the base layer 120 along the third direction D3 is in the range of 1 / 10 to 9 / 10. The organic film 140 includes a first film region 141. The first film region 141 is fixedly connected to the base layer 120.

[0089] A thinning structure is provided on the first membrane region 141. This thinning structure can be a third through hole 1411, a first groove, or both. Based on the design of the diaphragm layer 130 in Figures 8 to 11 , the organic membrane can be designed accordingly as shown in Figures 13 , 14 , 15 , and 16 .

[0090] For example, taking the thinning structure as the third through hole 1411, the length of the opening of the third through hole 1411 in the first direction is greater than the length in the second direction. Here, the first direction and the second direction are both parallel to the extension surface of the first membrane area 141, and the first direction and the second direction are perpendicular to each other. For example, referring to FIG14, the first direction D1 can be parallel to the edge of the base layer 120 along the Y direction, and the first direction D1 and the second direction D2 are perpendicular to each other. In addition, referring to FIG12, the first direction D1 can also be tilted relative to the edge of the base layer 120 along the Y direction, and the second direction D2 is perpendicular to the first direction D1. It can be understood that the first direction D1 and the second direction D2 shown in FIG12 and FIG14 are only examples made for ease of understanding, and this application does not limit the positional relationship of the first direction D1 relative to the base layer 120. The first direction and the second direction only need to meet the requirements of being parallel to the extension surface of the first membrane area 141 and being perpendicular to each other.

[0091] In this embodiment, referring to Figure 14, the first diaphragm 1312 and the second diaphragm 1313 are arranged relatively to each other, and in the area where the first edge 1316 of the first diaphragm 1312 and the second edge 1317 of the second diaphragm 1313 are parallel, the length value of the opening of the third through hole 1411 along the direction parallel to the first edge 1316 is greater than the length value along the direction perpendicular to the first edge 1316.

[0092] The length of the opening of the third through hole 1411 in the first direction D1 is less than 500 microns. The shape of the opening of the third through hole 1411 includes at least one of a rectangle, a diamond, an ellipse and a waist-shaped hole. The third through hole 1411 shown in Figure 12 is a waist-shaped hole. A plurality of third through holes 1411 can be provided on the first membrane area 141. The plurality of third through holes 1411 can be arranged parallel to each other on the organic film 140 (as shown in Figure 14), or can be arranged around each other (as shown in Figure 12). Those skilled in the art can design the shape, number and arrangement of the third through holes 1411 on the organic film according to actual needs, and this application is not limited to this.

[0093] In one embodiment, the length of the opening of the third through hole 1411 in the second direction D2 is less than 5 micrometers.

[0094] In one embodiment, the length of the opening of the third through hole 1411 in the first direction D1 is less than 500 micrometers and the length of the third through hole 1411 in the second direction D2 is less than 5 micrometers.

[0095] The organic film 140 is provided with a plurality of third through holes 1411, which facilitates the cantilever's large movement, thereby effectively vibrating the air. Due to the viscous resistance of the air, the amount of air passing through the third through holes 1411 is minimized, suppressing the drop in sound pressure caused by air escape, thereby preventing sound leakage.

[0096] When the first groove is located on the organic film 140 , the situation is similar to that when the third through hole 1411 is located on the organic film 140 , and is not described in detail herein.

[0097] Please refer to Figure 17, which is a schematic top view of a partial structure of the speaker unit 10. The speaker unit 10 in this embodiment has a substantially identical structure to the speaker unit 10 shown in Figure 3, comprising a circuit substrate 110, a base layer 120, a diaphragm layer 130, and an organic film 140 stacked sequentially along the thickness direction. Identical parts will not be repeated here. The difference is that the circuit substrate 110 and base layer 120 in this embodiment are cylindrical, and the corresponding diaphragm layer 130 is also circular. The circular speaker unit 10 can be used in headphone products or other products. Of course, in other embodiments, the speaker unit 10 can be configured in different shapes as needed. In this embodiment, the base layer 120 is annular in top view. The diaphragm 131 is fixed to the edge of the annular base layer 120. Exemplarily, there are three diaphragms 131. The three diaphragms 131 are respectively fixed to the periphery of the base layer 120, and the three diaphragms 131 intersect along the extension direction of the third direction D3. The first diaphragm 1312 is fixed to one side of the frame of the base layer 120 , and the second diaphragm 1313 and the third diaphragm 1314 are sequentially distributed around the center of the circle and fixed to other side surfaces of the frame of the base layer 120 .

[0098] In any of the aforementioned embodiments, the top view of the speaker unit 10 is rectangular. In this embodiment, the top view of the speaker unit 10 is circular. It is understood that this application does not limit the appearance of the speaker unit 10. Those skilled in the art can design the shape of the speaker according to actual needs.

[0099] The present application also provides a method for preparing a speaker unit. Below, the detailed steps of an exemplary method for preparing the speaker unit 10 proposed in an embodiment of the present invention are described with reference to Figures 18 and 19. The speaker unit 10 can be mainly obtained by graphical processing of the mask etching process to obtain a device shape, thereby preparing a speaker unit 10 with a complete MEMS (Micro-Electro-Mechanical System). The mask etching process can use different masks to obtain layers with different patterns on the multilayer structure shown in the B structure in Figure 19 by etching. Eight masks are required in the entire preparation process of manufacturing the speaker unit 10. The specific preparation steps are as follows:

[0100] In step S100 , a first electrode layer L1 , a vibration layer L2 , and a second electrode layer L3 are sequentially formed on a substrate to form a first base 150 .

[0101] Structure A in Figure 19 is a schematic diagram of the first base 150. The first base 150 is a combination of a first electrode layer L1, a vibration layer L2, and a second electrode layer L3. The first base 150 is disposed on a substrate, which may include a first silicon-based layer L4, a silicon oxide-based layer L5, and a second silicon-based layer L6.

[0102] On the base layer 120, a multilayer structure as shown in the structure B in FIG19 can be obtained by using RF magnetron sputtering or sol-gel deposition. The multilayer structure includes, from the upper side in the positive direction of the Y direction to the lower side in the negative direction of the Y direction, a first electrode layer L1, a vibration layer L2, a second electrode layer L3, a first silicon base layer L4, a silicon oxide layer L5, and a second silicon base layer L6. The first electrode layer L1 can be made of platinum or titanium. The vibration layer L2 can be made of a single crystal piezoelectric ceramic material, and the thickness of the vibration layer L2 is in the range of 2 microns to 4 microns. The second electrode layer L3 can be made of platinum or titanium, the first silicon base layer L4 is made of silicon with a thickness of approximately 8 microns, the silicon oxide layer is made of silicon dioxide with a thickness of approximately 1 micron, and the second silicon base layer L6 is made of silicon with a thickness of approximately 600 microns.

[0103] In step S200, a second groove 151 is formed on the first base 150. The second groove 151 sequentially penetrates the second electrode layer L3, the vibration layer L2 and the first electrode layer L1, separating the vibration layer L2 into a cantilever structure. The bottom surface of the second groove 151 is part of the substrate, forming a second base 160.

[0104] Specifically, step S200 can be subdivided into the following steps S201 to S203.

[0105] In step S201, based on the multi-layer structure shown in the B structure in FIG19 , the shape of the first electrode layer L1 is processed using a first mask, the first electrode layer L1 is etched, and part of the structure of the first electrode layer L1 is removed to form the first recesses L11 arranged at intervals as shown in the C structure in FIG19 , and the bottom surface of the first recess L11 is part of the vibration layer L2.

[0106] In step S202, a second mask is used to process the shape of the vibration layer L2, and the vibration layer L2 is etched to remove part of the structure of the vibration layer L2 to form a second recess L21 arranged at intervals as shown in the D structure in Figure 19. The bottom surface of the second recess L21 is part of the second electrode layer L3.

[0107] In step S203, a third mask is used to shape the second electrode layer L3, removing a portion of the second electrode layer L3 to form a third recess L31, as shown in structure E in Figure 19. The first recess L11, the second recess L21, and the third recess L31 together constitute a second recess 151. The second recess 151 is located on the first base 150. The second recess 151 sequentially passes through the second electrode layer L3, the vibration layer L2, and the first electrode layer L1, separating the vibration layer L2 into a cantilever structure. The bottom surface of the second recess 151 forms a portion of the substrate, forming the second base 160. The area of ​​the first base 150 after removing the second recess 151 constitutes the second base 160.

[0108] Step S300 : Covering the second substrate 160 with a passivation layer L7 .

[0109] A fourth mask is used to form a passivation layer L7. The passivation layer L7 is primarily formed on one side of the first electrode layer L1 in the thickness direction, sequentially covering the first electrode layer L1, the second groove, and the exposed edge of the first silicon-based layer L4, to form the F structure shown in FIG19 . The passivation layer L7 can be made of materials such as iridium, iridium dioxide, or iridium oxide. The passivation layer L7 is not limited to the above examples as long as it is dense, stable, and resistant to damage, and can block corrosion from various ions and water molecules.

[0110] In step S400 , a metal pattern layer L8 is formed on the passivation layer L7 , and at least a portion of the metal pattern layer L8 passes through the passivation layer L7 and is electrically connected to the second electrode layer L3 to form a third substrate 170 .

[0111] A metal pattern layer L8 is formed using a fifth mask. At least a portion of the metal pattern layer L8 is electrically connected to the first electrode layer L1 and the second electrode layer L3 and passes through the passivation layer L7 to form a G structure as shown in FIG. 19 .

[0112] Furthermore, the passivation layer L7 and the first silicon-based layer L4 are processed using a sixth mask to remove a portion of the passivation layer L7 and the first silicon-based layer L4 to form an H structure as shown in FIG. 19 .

[0113] In step S500 , an organic film 140 is formed on the third substrate, where the organic film covers the diaphragm 131 and the inner wall of the second groove 151 .

[0114] An organic film 140 is formed using a seventh mask and can be formed by a spin coating process or a photolithography process. The organic film 140 is primarily located on one side of the passivation layer L7 in the thickness direction. The organic film 140 covers the surface of the third substrate 170. Specifically, the organic film 140 sequentially covers the metal pattern layer L8, the second electrode layer L3, the first silicon-based layer L4, the silicon oxide-based layer L5, and the passivation layer L7, forming the I structure shown in FIG19 . The organic film 140 can be made of polyimide, acrylic, or the like.

[0115] In step S600 , a third through hole 1411 or a first groove is formed on a portion of the organic film 140 located at the bottom of the second groove 151 .

[0116] A plurality of third through holes 1411 or first grooves are formed in the portion of the organic film 140 at the bottom of the second groove 151 using a photolithography process. The silicon oxide layer L5 and the second silicon layer L6 are then processed using an eighth mask. The second silicon layer L6 is etched in the opposite direction of the Y direction to remove a portion of the silicon oxide layer L5 and the second silicon layer L6, thereby forming a J structure as shown in FIG. 19 .

[0117] Finally, the J structure shown in FIG19 can be fixed to the circuit substrate 110 by a dispensing process, and then electrically connected to the circuit substrate 110 (signal conduction) through connecting wires, thereby manufacturing the speaker unit 10 according to the present application.

[0118] The above processing steps can produce the speaker unit 10 shown in Figures 3 and 6. In the thickness direction, the second diaphragm 1313 has the same multilayer structure as the first diaphragm 1312. The multilayer structure of the first and second diaphragms 1312 and 1313 in the thickness direction will be described below using the first diaphragm 1312 as an example. As shown in the J structure in Figure 19, the first diaphragm 1312 includes a first electrode layer L1, a vibration layer L2, and a second electrode layer L3 stacked sequentially in the thickness direction. The vibration layer L2 is located between the first and second electrode layers L1 and L3, and the second electrode layer L3 is directly disposed on the base layer 120. Furthermore, as shown in the J structure in Figure 19, the passivation layer L7 is primarily disposed on the first electrode layer L1 and is located on one side of the first electrode layer L1 in the thickness direction. Different metal pattern layers L8 are connected to the first and second electrode layers L1 and L3, respectively. The metal pattern layers L8 pass through the passivation layer L7 and are partially located on one side of the passivation layer L7 in the thickness direction.

[0119] Thus, on the one hand, by providing a dual-diaphragm actuation structure, the speaker unit 10 has a dual cantilever structure that is opposed to each other and spaced apart. This improves the output power of the speaker unit 10 and maximizes the use of a small space, driving air vibration to maximize sound pressure generation, and fully achieving coverage of the acoustic characteristics of the frequency band. On the other hand, by providing an organic membrane 140 that completely encloses the first through-hole, a reduction in sound pressure is prevented without affecting the actuation of the first diaphragm 1312 and the second diaphragm 1313. More importantly, the provision of a plurality of third through-holes 1411 with high viscous resistance in the organic membrane 140 between the cantilevers reduces the Young's modulus of the organic membrane 140, allowing the organic membrane 140 to vibrate more easily under the drive of the first diaphragm 1312 and the second diaphragm 1313, thereby maximizing air vibration, generating sound pressure, and minimizing sound leakage, thereby maximizing sound pressure. Thus, the above structural design is conducive to minimizing the size of the speaker unit 10 and maximizing sound pressure within a limited space. Therefore, the speaker unit 10 of the present application can achieve both miniaturization and increased output power, and can meet the performance requirements of active noise reduction.

[0120] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A speaker unit, characterized in that: include: A base layer, wherein the base layer is in a frame structure and is provided with first through holes interpenetrating with each other in a thickness direction; a diaphragm layer, located on one side of the base layer in the thickness direction, comprising at least one diaphragm, a second through hole being provided between the diaphragm and the base layer and / or between two adjacent diaphragms, at least a portion of the edge of the diaphragm being fixedly connected to the base layer to form a cantilever structure, the diaphragm covering a portion of the first through hole, and the second through hole being connected to the first through hole; An organic film covers the diaphragm layer, the organic film includes a first film area, the first film area covers the second through hole, a thinning structure is provided on the first film area, and the thinning structure is used to reduce the Young's modulus of the first film area.

2. The speaker unit according to claim 1, characterized in that The thinning structure includes a third through hole and / or a first groove located on the first film area.

3. The speaker unit according to claim 2, characterized in that The opening of the third through hole and / or the first groove has a length in the first direction greater than a length in the second direction, the first direction and the second direction are both parallel to the extension surface of the first film region, and the first direction and the second direction are perpendicular.

4. The speaker unit according to claim 3, characterized in that The length of the opening of the third through hole and / or the first groove in the first direction is less than 500 micrometers; and / or the length of the third through hole in the second direction is less than 5 micrometers.

5. The speaker unit according to claim 3 or 4, characterized in that: A ratio of a thickness of the organic film to a length of the third through hole and / or the first groove in the second direction is in a range of 1 / 700 to 1 / 140.

6. The speaker unit according to any one of claims 1 to 5, characterized in that: The base layer includes a frame having the first through hole extending in the thickness direction, the direction in which the diaphragm extends from the frame to the first through hole is a third direction, and the ratio of the minimum width of the first membrane area along the third direction to the minimum width of the base layer along the third direction is in the range of 1 / 10 to 9 / 10.

7. The speaker unit according to claims 1-6, characterized in that: The first film area and the base layer are fixedly connected.

8. The speaker unit according to any one of claims 2 to 5, characterized in that: The shape of the opening of the third through hole and / or the first groove includes at least one of a rectangular, a diamond, an elliptical and a waist-shaped hole.

9. The loudspeaker unit according to any one of claims 1 to 8, characterized in that: There are multiple diaphragms, the multiple diaphragms are separated from each other, and at least a part of the second through hole is located between two adjacent diaphragms.

10. The speaker unit according to claim 9, characterized in that The diaphragm includes a first diaphragm and a second diaphragm that are arranged opposite to each other. The first diaphragm has a first edge on a side close to the second diaphragm, and the second diaphragm has a second edge on a side close to the first diaphragm. The second through hole is spaced between the first edge and the second edge.

11. The speaker unit according to claim 10, characterized in that At least a portion of the first edge is parallel to at least a portion of the second edge.

12. The speaker unit according to claim 11, characterized in that In a region where the first edge and the second edge are parallel, a length of the opening of the third through hole and / or the first groove along a direction parallel to the first edge is greater than a length along a direction perpendicular to the first edge.

13. The loudspeaker unit according to any one of claims 1 to 12, characterized in that: The base layer includes a frame, the frame has the first through hole extending in the thickness direction, the direction in which the diaphragm extends from the frame to the first through hole is a third direction, and the width of the diaphragm gradually decreases in the direction of the third direction.

14. The speaker unit according to claim 13, characterized in that The diaphragm has a trapezoidal structure.

15. The loudspeaker unit according to any one of claims 1 to 14, characterized in that: The organic film is made of polyimide, and the diaphragm is made of a single-crystal piezoelectric ceramic material.

16. A method for preparing a loudspeaker unit, for preparing the loudspeaker unit according to any one of claims 1 to 15, characterized in that: The steps include: A first electrode layer, a vibration layer, and a second electrode layer are sequentially prepared on a substrate to form a first matrix; forming a second groove on the first substrate, wherein the second groove sequentially penetrates the second electrode layer, the vibration layer and the first electrode layer to separate the vibration layer into a cantilever structure, and the bottom surface of the second groove is a part of the substrate to form a second substrate; Covering the second substrate with a passivation layer; Preparing a metal pattern layer on the passivation layer, wherein at least a portion of the metal pattern layer passes through the passivation layer and is electrically connected to the second electrode layer to form a third substrate; Covering the third substrate with an organic film, wherein the organic film covers the diaphragm and the inner wall of the second groove; A third through hole or the first groove is formed on a portion of the organic film located at the bottom of the first groove.

17. An electronic device, characterized in that: The invention comprises a controller and the speaker unit according to any one of claims 1 to 14, wherein the controller is electrically connected to the speaker unit and is used to drive the diaphragm layer in the speaker unit to vibrate.

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