speaker

Abstract

The speaker (100) includes a drive unit (110) that vibrates when driven by an electric signal, a vibration unit (120), a vibration transmission part (130) that connects the drive unit (110) and the vibration unit (120) and transmits vibrations to the vibration unit (120) to generate sound that is radiated outward, and a housing (140) that contains the drive unit (110), the vibration unit (120), and the vibration transmission part (130).

Description

[Technical field]

[0001] The present specification relates to the technical field of acoustics, and in particular to speakers.

[0002] [Incorporated by reference] This application claims priority to a Chinese application having application number 202211392438.X, filed on November 8, 2022, the entire contents of which are incorporated herein by reference. [Background technology]

[0003] A speaker mainly includes a driving part, a vibrating part, a vibration transmission part and a housing, and the vibrating part is an important component of the speaker. The vibrating part may be a vibrating membrane assembly including a vibrating membrane, a central reinforcement part, etc. When the driving force of the driving part is determined, the vibrating part can be reasonably designed so that the vibrating part and the driving part can achieve good mechanical impedance matching, thereby achieving a high sound pressure level and a wide bandwidth output effect.

[0004] However, currently used speakers, especially micro speakers, have problems such as insufficient driving capacity of the vibrating unit. Therefore, in order to achieve high sound pressure level output, it is necessary to research and improve the driving capacity of the driving unit in the speaker and optimize the structure of the vibrating unit to match it, thereby achieving a higher sound output effect. Summary of the Invention [Means for solving the problem]

[0005] An embodiment of the present specification provides a speaker, the speaker including: a drive unit that vibrates when driven by an electric signal; a vibration unit; a vibration transmission part that connects the drive unit and the vibration unit and transmits the vibration to the vibration unit to generate sound that is radiated outward; and a housing that accommodates the drive unit, the vibration unit, and the vibration transmission part.

[0006] Additional features are set forth in part in the description that follows, and will become apparent to one of ordinary skill in the art upon examination of the following material and drawings, or may be learned by the practice or operation of the embodiments. The features of the specification can be realized and attained by practicing or using various aspects of the methods, tools and combinations that are described in the detailed embodiments that follow.

[0007] The present application will be further illustrated by exemplary embodiments, which are described in detail with reference to the drawings, in which the embodiments are not limiting and in which the same reference numerals indicate the same structures. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of an exemplary speaker in accordance with some embodiments of the present disclosure. [Figure 2A] FIG. 1 is a schematic diagram of an exemplary speaker in accordance with some embodiments of the present disclosure. [Figure 2B] 2B is an exemplary cross-sectional view of the speaker shown in FIG. 2A. [Figure 2C] 2B is another exemplary cross-sectional view of the speaker shown in FIG. 2A. [Figure 2D] 2B is yet another exemplary cross-sectional view of the speaker shown in FIG. 2A. [Diagram 3] FIG. 2 is a schematic diagram of an example diaphragm assembly in accordance with some embodiments of the present disclosure. [Figure 4] FIG. 2 is a schematic diagram of an example drive unit according to some embodiments of the present disclosure. [Diagram 5] FIG. 2 is a diagram of an example piezoelectric beam in accordance with some embodiments of the present disclosure. [Figure 6] 1 is a schematic diagram of an example piezoelectric layer in accordance with certain embodiments of the present disclosure. [Figure 7] FIG. 2 is an exemplary diagram of a diaphragm assembly according to some embodiments of the present disclosure. [Figure 8]FIG. 10 is a comparison diagram of frequency response curves of a speaker when a diaphragm assembly according to some embodiments of the present disclosure has different area ratios. [Figure 9] 1A-1C are exemplary configuration diagrams of a central reinforcement portion according to some embodiments of the present disclosure. [Figure 10] 10A-10C are comparative diagrams of frequency response curves of speakers when the central reinforcement portion has different area ratios, according to some embodiments of the present disclosure. [Figure 11] 1A-1C are exemplary configuration diagrams of a central reinforcement portion according to some embodiments of the present disclosure. [Figure 12] 1A-1C are exemplary configuration diagrams of a central reinforcement portion according to some embodiments of the present disclosure. [Figure 13] 1A-1C are exemplary configuration diagrams of a central reinforcement portion according to some embodiments of the present disclosure. [Figure 14] 10A-10C are comparative diagrams of frequency response curves of speakers when the central reinforcement portion has different structures, according to some embodiments of the present disclosure. [Figure 15A] 1 is an example configuration diagram of a coupled elastic structure according to some embodiments of the present disclosure. [Figure 15B] 1 is a schematic diagram of a hierarchical distribution along the vibration direction of a piezoelectric beam in accordance with some embodiments of the present disclosure. [Figure 16] 10A-10C are comparative diagrams of frequency response curves of a speaker with different parameters of a coupled elastic structure, in accordance with some embodiments of the present disclosure. [Figure 17] 13A-13C are diagrams illustrating other exemplary configurations of a coupled resilient structure according to some embodiments of the present disclosure. [Figure 18] 11A-11C are comparative diagrams of frequency response curves of a speaker when the coupled elastic structure has different shape structures, according to some embodiments of the present disclosure. [Figure 19] 4A-4C are frequency response curve diagrams of a speaker corresponding to different parameters α, in accordance with some embodiments of the present disclosure. [Figure 20] FIG. 1 is a schematic diagram of a speaker according to some embodiments of the present disclosure. [Figure 21]1 illustrates a frequency response curve diagram of a speaker corresponding to different physical parameters β, in accordance with some embodiments of the present disclosure. [Figure 22A] 1A-1C are schematic diagrams of deformations of piezoelectric beams of different shapes in accordance with some embodiments herein. [Figure 22B] 1A-1C are schematic diagrams of deformations of piezoelectric beams of different shapes in accordance with some embodiments herein. [Figure 23] 1 is a schematic diagram of a trapezoidal piezoelectric beam in accordance with some embodiments of the present disclosure; [Figure 24] 1 illustrates a frequency response curve diagram of a speaker corresponding to different physical parameters θ, in accordance with some embodiments of the present disclosure. [Figure 25A] 1A-1C are schematic diagrams of piezoelectric beams of different geometric configurations in accordance with some embodiments of the present disclosure. [Figure 25B] 1A-1C are schematic diagrams of piezoelectric beams of different geometric configurations in accordance with some embodiments of the present disclosure. [Figure 25C] 1A-1C are schematic diagrams of piezoelectric beams of different geometric configurations in accordance with some embodiments of the present disclosure. [Figure 25D] 1A-1C are schematic diagrams of piezoelectric beams of different geometric configurations in accordance with some embodiments of the present disclosure. [Figure 25E] 1A-1C are schematic diagrams of piezoelectric beams of different geometric configurations in accordance with some embodiments of the present disclosure. [Figure 25F] 1A-1C are schematic diagrams of piezoelectric beams of different geometric configurations in accordance with some embodiments of the present disclosure. [Figure 26] 1 is a schematic diagram of a plurality of piezoelectric beams in accordance with certain embodiments of the present disclosure; [Figure 27A] 1A-1C are schematic diagrams of deformation of a piezoelectric beam with different electrode distributions in accordance with some embodiments herein. [Figure 27B] 1A-1C are schematic diagrams of deformation of a piezoelectric beam with different electrode distributions in accordance with some embodiments herein. [Figure 28] FIG. 2 is a schematic diagram of a distribution of electrodes on a piezoelectric beam in accordance with some embodiments of the present disclosure. [Figure 29A]1A-1C are schematic diagrams of simulated deformation of a piezoelectric beam with different electrode distribution scenarios in accordance with some embodiments herein. [Figure 29B] 1A-1C are schematic diagrams of simulated deformation of a piezoelectric beam with different electrode distribution scenarios in accordance with some embodiments herein. [Diagram 30] FIG. 29C is a response curve diagram of a speaker corresponding to the two electrode distribution conditions shown in FIGS. 29A and 29B. [Diagram 31] 4A-4C are frequency response curve diagrams of a speaker corresponding to different physical parameters γ, in accordance with some embodiments of the present disclosure. [Diagram 32] 4A-4C are frequency response curve diagrams of a speaker corresponding to different physical parameters τ, in accordance with some embodiments of the present disclosure. [Diagram 33] FIG. 2 is a schematic diagram of a distribution of electrodes on a piezoelectric beam in accordance with some embodiments of the present disclosure. [Diagram 34] 1 illustrates frequency response curve diagrams of a speaker corresponding to different physical parameters μ, in accordance with some embodiments of the present disclosure. [Diagram 35] 4 is a frequency response curve diagram of a speaker corresponding to different physical parameters x, in accordance with some embodiments of the present disclosure. [Diagram 36] 13 is a schematic diagram of another distribution of electrodes on a piezoelectric beam, according to some embodiments of the present disclosure; [Figure 37] 4 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters z, in accordance with some embodiments of the present disclosure. [Figure 38] 1 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters m, according to some embodiments of the present disclosure. [Figure 39] 1 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters y, in accordance with some embodiments of the present disclosure. [Diagram 40] 13 is a schematic diagram of another distribution of electrodes on a piezoelectric beam, according to some embodiments of the present disclosure; [Diagram 41]1 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters μ′ in accordance with some embodiments of the present disclosure. [Diagram 42] 1 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters γ′, in accordance with some embodiments of the present disclosure. [Diagram 43] 1A-1C are frequency response curve diagrams of a speaker corresponding to different electrode shapes in accordance with some embodiments of the present disclosure. [Diagram 44] 13 is a schematic diagram of another distribution of electrodes on a piezoelectric beam, according to some embodiments of the present disclosure; [Diagram 45] 4A-4C are frequency response curve diagrams of a speaker corresponding to different physical parameters η, in accordance with some embodiments of the present disclosure. [Figure 46] 13 is a schematic diagram of another distribution of electrodes on a piezoelectric beam, according to some embodiments of the present disclosure; [Figure 47] 1A and 1B are frequency response curve diagrams of speakers equipped with a double arc electrode and a fully covered electrode, respectively, in accordance with some embodiments of the present disclosure. [Figure 48] FIG. 2 is a schematic diagram of an electrode extraction method for a piezoelectric beam according to some embodiments of the present specification. [Figure 49A] FIG. 13 is a schematic diagram of an electrode attached to a piezoelectric beam, according to some embodiments herein. [Figure 49B] FIG. 13 is a schematic diagram of an electrode attached to a piezoelectric beam, according to some embodiments herein. [Figure 50A] 1 is a schematic diagram of a piezoelectric beam in accordance with some embodiments of the present disclosure. [Figure 50B] 1 is a schematic diagram of a piezoelectric beam in accordance with some embodiments of the present disclosure. [Figure 50C] FIG. 50B is a cross-sectional view of the piezoelectric beam shown in FIG. 50A along AA. [Figure 50D] FIG. 50B is a cross-sectional view along BB of the piezoelectric beam shown in FIG. 50A. [Figure 51A] 1 is another schematic diagram of a piezoelectric beam in accordance with some embodiments of the present disclosure. [Figure 51B] FIG. 51B is an enlarged view of region D in FIG. 51A. [Figure 51C] FIG. 51B is a cross-sectional view of the piezoelectric beam shown in FIG. 51A along AA. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In order to more clearly describe the technical means of the embodiments of the present application, the drawings necessary for the description of the embodiments are briefly described below. Obviously, the drawings described below are only some examples or embodiments of the present application, and those skilled in the art can apply the present application to other similar scenarios based on these drawings without creative efforts. Unless otherwise clear from the context or described otherwise, the same numbers in the drawings indicate the same structures or operations.

[0010] It should be understood that the terms "system," "apparatus," "unit," and / or "module" used herein are ways of distinguishing between different levels of assemblies, parts, components, portions, or structures, however, other terms may be used in place of the above terms if they achieve the same purpose.

[0011] As used in this application and the claims, unless the context clearly dictates otherwise, terms such as "a," "one," "one kind," and / or "the" do not specifically refer to the singular but may include the plural. In general, the terms "comprise" and "containing" are intended to indicate only the inclusion of explicitly identified steps and elements, and these steps and elements are not intended to be an exclusive listing, and a method or apparatus may also include other steps or elements.

[0012] In this application, flowcharts are used to describe the operations performed by the system according to the embodiments of this application. It should be understood that the preceding and subsequent operations are not necessarily performed in exact order. Instead, the steps may be processed in reverse order or simultaneously. Also, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0013] 1 is a schematic diagram of an exemplary speaker according to some embodiments of the present disclosure. In some embodiments, as shown in FIG. 1, a speaker 100 may include a driving unit 110, a vibration unit 120, a vibration transmission unit 130, and a housing 140.

[0014] The driving unit 110 is a transducer device of the speaker 100 and can vibrate when driven by an electric signal, i.e., the driving unit 110 can provide a driving force to the speaker 100 (e.g., the vibration unit 120) by converting an electric signal into a vibration signal. In some embodiments, the driving type of the driving unit 110 may include different types such as electromagnetic, electrostatic, piezoelectric, etc. For more information on the driving unit 110, please refer to other parts of this specification (e.g., Figures 19 to 26 and their descriptions).

[0015] The vibrating unit 120 (or called a diaphragm assembly), also called a load part of the loudspeaker 100, may radiate sound pressure outward in response to a vibration signal generated by the driving unit 110. In some embodiments, the vibrating unit 120 may include a diaphragm 121 and a central reinforcement part 122. The diaphragm 121 may include a fixed part 1211, a central part 1212, and a folded part 1213, and the diaphragm 121 may be connected to the housing 140 via the fixed part 1211, and the folded part 1213 may be disposed between the fixed part 1211 and the central part 1212. In some embodiments, the folded part 1213 may cause the diaphragm 121 to be recessed inward (e.g., toward the driving unit 110) or protrude outward (e.g., away from the driving unit 110) with respect to the housing 140. For example only, the fold 1213 may be recessed inward, in which case the front cavity 150 does not need to accommodate the fold 1213, thereby reducing the thickness of the front cavity 150 and further reducing the thickness of the speaker. Also, for example, when the distance between the diaphragm 121 and the driving unit 110 is short, the depth of the fold 1213 along the vibration direction of the vibration unit 120 may be limited, in which case the fold 1213 may protrude outward, so that the fold 1213 has a large depth, which can further improve the elastic coefficient of the diaphragm 121 and ensure the output effect of the speaker 100. The central reinforcing portion 122 may be a reinforcing structure disposed in the central portion 1212 to reinforce its vibration. In some embodiments, the central reinforcing portion 122 may be located in a part or the entire area of ​​the central portion 1212, and may adjust and control the modes of the diaphragm 121 in different frequency bands (e.g., higher order modes of high frequency). In some embodiments, the drive unit 110 may be connected to the central reinforcement 122 or to the central portion 1212, thereby realizing the transfer of mechanical energy from the drive end to the load end. For further description of the vibration unit 120, reference may be made elsewhere herein (e.g., Figures 7-14 and their descriptions).

[0016] The vibration transmission unit 130 refers to a structure or assembly that transmits vibration. In some embodiments, the vibration transmission unit 130 may include a vibration transmission column 131 and a coupling elastic structure 132. In some embodiments, the vibration transmission unit 130 may connect the driving unit 110 and the vibration unit 120, and transmit vibration to the vibration unit 120 to generate sound that radiates outward. Exemplarily, the coupling elastic structure 132 in the vibration transmission unit 130 may be connected to the driving unit 110 and the vibration transmission column 131, respectively, and couple the vibration generated by the driving unit 110 to the vibration transmission column 131. The vibration transmission column 131 may be connected to the vibration unit 120 to further transmit the vibration generated by the driving unit 110 to the vibration unit 120, and further generate sound that radiates outward. In some embodiments, the stiffness of the vibration transmission unit 130 as a whole may be easily adjusted by installing the coupling elastic structure 132, so that the stiffness of the vibration transmission unit is within a predetermined range. For example, if the vibration transmitting part 130 includes only the vibration transmitting pillars 131, the rigidity of the entire vibration transmitting part 130 may be too large, which is disadvantageous for the vibration transmitting part 130 to transmit vibration. On the other hand, if the vibration transmitting part 130 includes the connecting elastic structures 132, the rigidity of the vibration transmitting part 130 can be adjusted by adjusting the number and structure (e.g., dimensions, etc.) of the connecting elastic structures 132, thereby improving the vibration transmission effect of the vibration transmitting part 130.

[0017] The housing 140 refers to a structure that houses other assemblies of the speaker 100. In some embodiments, the housing 140 may house the driving unit 110, the vibration unit 120, and the vibration transmission part 130. In some embodiments, the housing 140 may enclose and form a cavity, which includes a front cavity 150 and a rear cavity 160. For example, as shown in FIG. 1, the housing 140 together with the side of the vibration unit 120 away from the driving unit 110 constitutes the front cavity 150 of the speaker 100, and together with the side of the driving unit 110 away from the vibration unit 120 constitutes the rear cavity 160 of the speaker 100. In some embodiments, corresponding structures such as sound holes (not shown), damping mesh 180, etc. are installed in the front cavity 150 and the rear cavity 160 to form a cavity damping adjustment part of the speaker 100, thereby realizing the adjustment of the sensitivity and Q value of the frequency response curve of the speaker 100, and making the frequency response curve of the output sound pressure levels (SPL) of the speaker 100 flatter.

[0018] Fig. 2A is a schematic diagram of an exemplary loudspeaker according to some embodiments of the present disclosure. Fig. 2B is an exemplary cross-sectional view of the loudspeaker shown in Fig. 2A. Fig. 2C is another exemplary cross-sectional view of the loudspeaker shown in Fig. 2A. Fig. 2D is yet another exemplary cross-sectional view of the loudspeaker shown in Fig. 2A.

[0019] As shown in Figures 2A to 2D, the overall structure of the speaker 100 may be rectangular. The shape of the overall structure of the speaker 100 may refer to the shape of a certain surface (e.g., the shape of the upper surface in the vibration direction of the vibration unit 120 of the speaker 100). The structure of the speaker 100 shown in Figure 2A is merely an illustrative example, and in some other embodiments, the speaker 100 may have other shapes, such as a regular shape such as a circle, a triangle, a quadrilateral, a racetrack shape, or other irregular shapes.

[0020] 2A to 2D, the speaker 100 may include a driving unit 110, a vibration unit 120, a vibration transmission part 130, a housing 140, and a back plate 170. The vibration transmission part 130 includes a vibration transmission post 131 and a coupling elastic structure 132.

[0021] As shown in FIG. 2C , the back plate 170 may be connected to the housing 140 and may mount or support the driving unit 110. The coupling elastic structure 132 may be connected to the driving unit 110 and the vibration transmission column 131, respectively, and may couple the vibration generated by the driving unit 110 to the vibration transmission column 131. The vibration transmission column 131 may be connected to the vibration unit 120 to further transmit the vibration generated by the driving unit 110 to the vibration unit 120, and further generate sound that radiates outward. In some embodiments, the coupling elastic structure 132 may use a metal material such as stainless steel, aluminum alloy, magnesium-lithium alloy, copper, or copper alloy. In some embodiments, the coupling elastic structure 132 may use a metal material such as Si, SiO 2、 A single layer of semiconductor material such as SiNx, SiC, etc. may be used. In some embodiments, the bonded elastic structure 132 may be a multi-layer semiconductor material such as Si / SiO2, SiO2 / Si, Si / SiNx, SiNx / Si. In some embodiments, the bonded elastic structure 132 may be a single layer of polymer material such as Polyimide (PI), PET, PEI, Parylene, Polydimethylsiloxane (Pdms), hydrogel, photoresist, silicone rubber, silicone gel, silicone sealant, FPC, PEEK, etc. In some embodiments, the bonded elastic structure 132 may be a multi-layer composite polymer material or a multi-layer composite material of semiconductor and polymer. In some embodiments, the bonded elastic structure 132 may be various anisotropic materials such as carbon fiber, FR4, etc. For more information on the bonded elastic structure 132, please refer to other parts of this specification (e.g., Figures 15A to 18 and their descriptions).

[0022] The vibration unit 120 (e.g., the vibration membrane 121) may be connected to the housing 140. The vibration transmission column 131 may connect the driving unit 110 and the vibration unit 120 (e.g., the central reinforcement part 122). In some embodiments, the vibration transmission column 131 and the coupling elastic structure 132, as a vibration transmission structure, transmit the vibration generated by the driving unit 110 to the vibration unit 120, so that the vibration unit 120 vibrates along its vibration direction (e.g., the z direction shown in FIG. 2A). In some embodiments, a cavity 115 may be configured between the vibration unit 120 and the driving unit 110, and when the driving unit 110 vibrates, the cavity 115 may further cause a change in air pressure inside the cavity 115, thereby vibrating the vibration unit 120. In some embodiments, as shown in FIG. 2D, the vibration transmission column 131 may further include a relief groove 1311. The clearance groove 1311 may be provided in the vibration transmitting column 131 at a position facing the bent portion 1213 of the diaphragm 121 (for example, the clearance groove 1311 and at least a part of the bent portion 1213 overlap in a projection direction along the vibration direction of the diaphragm 121), and may prevent the bent portion 1213 from interfering with the vibration transmitting column 131 when the diaphragm 121 vibrates, while at the same time reducing the volume of the cavity of the speaker 100 and further reducing the thickness of the speaker 100. In some embodiments, the vibration transmitting column 131 may have high rigidity and low density so as to be able to transmit vibrations better.

[0023] It should be noted that the back plate 170 may be a part of the housing 140, that is, the back plate 170 may be integrally formed with the housing 140 so as to mount or support the drive unit 110 thereon.

[0024] FIG. 3 is a schematic diagram of an example vibration unit according to some embodiments of the present disclosure.

[0025] As shown in FIG. 3, the central reinforcing portion 122 may be located in the central region of the vibrating membrane 121. In some embodiments, the central reinforcing portion 122 may be located in the center 1212 of the vibrating membrane 121 and attached to the surface of the center 1212. For example, the central reinforcing portion 122 may be equal in area to the center 1212, and the projection of the central reinforcing portion 122 in the vibration direction of the vibrating unit 120 and the projection of the central portion 1212 in the vibration direction of the vibrating unit 120 may overlap. Also, for example, the central reinforcing portion 122 may be smaller in area than the center 1212 and may be distributed symmetrically along the center of the center 1212 to balance the vibration of the vibrating membrane 121. In some embodiments, the material of the central reinforcing portion 122 may include a metal material. Exemplary metal materials may include, but are not limited to, stainless steel, aluminum alloy, magnesium-lithium alloy, copper, copper alloy, and the like. In some embodiments, the material of the central reinforcing portion 122 may include various anisotropic materials. Exemplary anisotropic materials may include, but are not limited to, carbon fiber, FR4, plant fiber, and the like. In some embodiments, the material of the central reinforcement portion 122 may include various polymer materials, such as polyimide (PI), PET, PEI, FPC, PEEK, and the like. In some embodiments, the central reinforcement portion 122 may adjust and control the modes of the diaphragm 121 in different frequency bands. In some embodiments, the parameters (e.g., mass, area, and the like) of the central reinforcement portion 122 may be adjusted to adjust the compliance of the diaphragm 121 to adjust the output of the speaker 100. In some embodiments, the central reinforcement portion 122 may have a plurality of apertures 1221 disposed therein, and the plurality of apertures 1221 are arranged on the surface of the central reinforcement portion 122. In some embodiments, the shape of the apertures 1221 may be a regular and / or irregular geometric shape, such as a circle, an ellipse, a triangle, a rectangle, a trapezoid, a pentagon, a hexagon, and the like. In some embodiments, the dimensions of the multiple apertures 1221 (here referring to the dimensions of a single aperture 1221) may be the same or different, and the spacing between two adjacent apertures 1221 among the multiple apertures 1221 may be the same or different.For a more detailed explanation of the central reinforcing portion 122, reference may be made to other parts of this specification (eg, FIGS. 7 to 14 and their explanations).

[0026] FIG. 4 is a schematic diagram of an example drive unit according to some embodiments of the present disclosure.

[0027] In some embodiments, the driving unit 110 may include one or more, for example, two, three, four or more, piezoelectric beams 111. The piezoelectric beams 111 may include a piezoelectric layer that may deform in response to an electrical signal to vibrate the piezoelectric beams 111. In some embodiments, the vibration direction of the piezoelectric beams 111 (e.g., the z-direction shown in FIG. 4 ) may be perpendicular to the longitudinal direction of the piezoelectric beams 111 (e.g., the x-direction shown in FIG. 4 ). As shown in FIG. 4, the number of the piezoelectric beams 111 may be four, and the four piezoelectric beams 111 have one end (or called fixed end) fixed to the back plate 170, and the other end (or called free end) connected to the vibration transmission column 131 of the speaker 100 via the coupling elastic structure 132, thereby transmitting the driving force and displacement generated by the driving unit 110 to the vibration unit 120 (e.g., the vibrating membrane 121, the central reinforcement part 122, etc.) via the vibration transmission column 131 to realize the outward radiation of sound pressure. In some embodiments, when the driving unit 110 includes a plurality of piezoelectric beams 111, the plurality of piezoelectric beams 111 may be distributed symmetrically in the circumferential direction of the vibration transmission structure. For example, when the number of the plurality of piezoelectric beams 111 is an odd number, the plurality of piezoelectric beams 111 may be distributed symmetrically around the vibration transmission column 131. Furthermore, for example, when the number of the plurality of piezoelectric beams 111 is an even number, the plurality of piezoelectric beams 111 may be distributed axially symmetrically around the vibration transmitting column 131 .

[0028] In some embodiments, the number of coupled elastic structures 132 corresponding to each piezoelectric beam 111 may be one or more. In some embodiments, each piezoelectric beam 111 may correspond to two coupled elastic structures 132. For example, one end of each piezoelectric beam 111 may be connected to two coupled elastic structures 132, and when the number of piezoelectric beams 111 is four, the number of coupled elastic structures 132 may be eight.

[0029] In some embodiments, as shown in FIG. 1 and FIG. 4, the housing 140 may surround the cavity, and the piezoelectric beam 111 may have a part fixedly connected to the housing 140 (or the back plate 170) to form a fixed region 111-1, and another part suspended and installed above the cavity to form a suspended region 111-2. The piezoelectric beam 111 may be connected to the housing 140 (or the back plate 170) through the fixed region 111-1 to realize the mounting and fixing of the piezoelectric beam 111. The suspended region 111-2 may be deformed and vibrated by the piezoelectric effect. In some embodiments, in the longitudinal direction of the piezoelectric beam 111, one end of the piezoelectric beam 111 forming the fixed region 111-1 may be called a fixed end, and the other end may be called a free end.

[0030] FIG. 5 is a close-up diagram of an example piezoelectric beam in accordance with certain embodiments of the present disclosure.

[0031] As shown in FIG. 5, the piezoelectric beam 111 may include a substrate layer 1111 and piezoelectric layers 1112 symmetrically distributed on both sides of the substrate layer 1111, and electrode layers 1113 are further disposed on the upper and lower surfaces of each piezoelectric layer 1112. The number of piezoelectric layers 1112 located on both sides of the substrate layer 1111 may be one or more, for example, two, three, four, five or more. For example, the number of piezoelectric layers 1112 may be one, which is advantageous for miniaturizing the speaker structure. In some embodiments, the number of piezoelectric layers 1112 may be multiple, and the multiple piezoelectric layers 1112 may be deformed simultaneously under the action of an applied voltage, thereby improving the driving force of the piezoelectric beam 111. Illustratively, FIG. 6 is a schematic configuration diagram of an exemplary piezoelectric layer according to some embodiments of the present specification. 6, the number of substrate layers 1111 in the piezoelectric beam 111 may be one, and both sides of the substrate layer 1111 along the vibration direction may include three piezoelectric layers 1112, and electrode layers 1113 are provided on both sides of each piezoelectric layer 1112, so that the total number of electrode layers 1113 in the piezoelectric beam 111 may be eight. For more detailed explanations regarding the electrode layers, please refer to other parts of this specification (e.g., FIGS. 27A to 51C and their explanations).

[0032] In some embodiments, in order to ensure that the piezoelectric beam 111 has a large displacement in its vibration direction, the polarization direction of the piezoelectric layer 1112 of each layer and the positive and negative of the applied voltage can be designed to reverse the deformation direction of the piezoelectric layers 1112 located on both sides of the substrate layer 1111, i.e., one side expands and the other side contracts. For example, the potential of the voltage applied to the piezoelectric layer 1112 on one side of the substrate layer 1111 can be reversed to the polarization direction of the piezoelectric layer, in which case the piezoelectric layer 1112 contracts due to the inverse piezoelectric effect, and the potential of the voltage applied to the piezoelectric layer 1112 on the other side of the substrate layer 1111 can be made the same as the polarization direction of the piezoelectric layer, in which case the piezoelectric layer 1112 expands due to the inverse piezoelectric effect, and the expansion and contraction deformations work together to cause the piezoelectric beam 111 to curl along the direction of the contraction deformation, to be largely displaced, and to vibrate further. In some embodiments, the polarization directions of any two adjacent piezoelectric layers 1112 may be opposite, and the applied voltage may make the electric potential direction of each piezoelectric layer 1112 on one side of the substrate layer 1111 the same as the polarization direction, and the electric potential direction of each piezoelectric layer 1112 on the other side of the substrate layer 1111 the opposite to the polarization direction. In some embodiments, the number of layers of the piezoelectric layers 1112 on both sides of the substrate layer 1111 may be the same, in which case, the neutral layer of the piezoelectric beam 111 may be located inside the substrate layer 1111. In some embodiments, the number of layers of the piezoelectric layers 1112 on both sides of the substrate layer 1111 may be different, in which case, the neutral layer of the piezoelectric beam 111 may not be located inside the substrate layer 1111, so that the desired neutral layer can be obtained by the asymmetric design of the piezoelectric layers 1112 to achieve the desired displacement output effect. In some embodiments, the polarization directions of the piezoelectric layers 1112 on both sides of the substrate layer 1111 may be the same or opposite. In some embodiments, when the substrate layer 1111 is a metallic material, the polarization directions of the piezoelectric layers 1112 on both sides of the substrate layer 1111 may be the same.

[0033] In some embodiments, the material of the piezoelectric layer 1112 may include AlN, PZT, ZnO, etc. The material of the electrode layers 1113 located on both sides of the piezoelectric layer 1112 may include Ag, Mo, Cu, Au, Ti / Au, Al, etc. In some embodiments, the material of the vibration transmitting columns 131 may be the same as the material of the substrate layer 1111. Note that in some embodiments, the material of the substrate layer 1111 may be different from the material of the coupling elastic structure 132 described above.

[0034] In some embodiments, the aforementioned speaker 100 can be manufactured by the following process, which includes steps 1 to 8.

[0035] In step 1, a piezoelectric driving layer (e.g., the piezoelectric layer 1112 and the electrode layer 1113 shown in FIG. 5 or FIG. 6) is manufactured. In some embodiments, the piezoelectric driving layer may be manufactured using a first manufacturing process. For example, a bulk body may be sintered to form a single-layer ceramic sheet, and then a corresponding electrode layer may be printed and each layer may be bonded to form a piezoelectric ceramic stack structure. For bonding, an electrode material may be used for bonding, for example, the electrode material may be silver paste, and an adhesive may be used for bonding. In some embodiments, the piezoelectric driving layer may be manufactured using a second manufacturing process. For example, an electrode may be printed and cured on a substrate, a piezoelectric ceramic paste may be applied, and the steps may be repeated to form a multi-layer co-fired structure (or called a piezoelectric ceramic stack structure).

[0036] In step 2, the piezoelectric beam structure is fabricated. In some embodiments, a substrate structure may be formed using methods such as machining, etching, etc., and then the piezoelectric ceramic laminate structure may be connected (e.g., glued) to the corresponding position of the substrate to obtain the piezoelectric beam structure.

[0037] In step 3, conductive electrodes are fabricated. In some embodiments, silver paste electrodes can electrically lead the electrodes of each layer that need to be applied with the same voltage correspondingly.

[0038] In step 4, the piezoelectric beam structure and the back plate are assembled. In some embodiments, a corresponding electrode structure is designed for both the piezoelectric beam and the back plate (e.g., the back plate 170 in FIG. 2A-2C), and the corresponding electrode structure can realize the electrical and mechanical connection between the piezoelectric beam and the back plate. In some embodiments, the piezoelectric beam and the back plate can be connected using an adhesive, or the electrode structure and the adhesive can be used simultaneously to connect the piezoelectric beam and the back plate.

[0039] In step 5, the piezoelectric beam structure and the vibration transmission structure are assembled. In some embodiments, the piezoelectric beam structure and the vibration transmission part (eg, the coupling elastic structure 132, the vibration transmission column 131) may be connected by adhesive.

[0040] In step 6, the housing and central reinforcement are manufactured. In some embodiments, the manufacturing of the housing (e.g., housing 140) and central reinforcement (e.g., central reinforcement 122) may use metallic or non-metallic materials. In some embodiments, methods such as machining, etching, etc. may be used to form the housing structure.

[0041] In step 7, the vibrating unit (or called the vibrating membrane assembly) is manufactured. In some embodiments, the housing and the central reinforcement part are positioned using a mold, and the housing, the central reinforcement part and the vibrating membrane (e.g., the vibrating membrane 121) can be formed into an assembly using a hot press molding or injection molding process, and the adhesion between the vibrating membrane and the housing and the central reinforcement part can be realized by adhesive, i.e., they are connected by intermolecular force.

[0042] In step 8, the speaker is assembled. In some embodiments, the driving unit and the vibration unit may be positioned by a positioning jig, and corresponding adhesives may be applied between the vibration transmission structure and the vibrating membrane, and between the housing and the back plate, to realize adhesion and assembly of the driving unit and the vibration unit.

[0043] In some embodiments, a microelectromechanical systems (MEMS) process may be used to fabricate the above-mentioned speaker 100, which includes steps 1 to 7.

[0044] In step 1, a piezoelectric driving layer is manufactured. In some embodiments, multiple layers of the piezoelectric driving layer may be manufactured on a substrate by processes such as sputtering, photolithography, etching, etc., and an electrical conductive structure for each corresponding layer may be formed.

[0045] In step 2, the piezoelectric beam structure is manufactured. In some embodiments, for the structure located on one side of the substrate of the piezoelectric driving layer, a substrate may be formed by photolithography and etching, and a piezoelectric beam structure may be further formed. In some embodiments, the substrate is a base material such as a semiconductor material (e.g., silicon, silicon dioxide, silicon nitride, silicon carbide, etc.), and the substrate may be formed by photolithography, etching, etc. on the substrate. In some embodiments, the substrate is an additional material such as a semiconductor material (e.g., silicon, silicon dioxide, silicon nitride, silicon carbide, etc.) or a polymer material (e.g., PI, PDMS, etc.), and the substrate may be formed by sputtering, deposition or spin coating, and photolithography, etching, etc. For the structure in which the piezoelectric driving layers are distributed on both sides of the substrate, a substrate may be formed by photolithography and etching, and the structures located on one side of the substrate of the two piezoelectric driving layers are bonded by a bonding process, thereby forming a structure in which the piezoelectric driving layers are distributed on both sides of the substrate.

[0046] In step 3, the piezoelectric beam structure and the back plate are assembled. In some embodiments, the piezoelectric beam and the back plate are both designed with corresponding electrode structures, and the corresponding electrode structures can realize the electrical and mechanical connection between the piezoelectric beam and the back plate. In some embodiments, the piezoelectric beam and the back plate can be further connected using an adhesive, or the electrode structure and the adhesive can be used to connect the piezoelectric beam and the back plate at the same time.

[0047] In step 4, the piezoelectric beam structure and the vibration transmission structure are assembled. In some embodiments, the piezoelectric beam structure and the vibration transmission structure (eg, the coupling elastic structure 132, the vibration transmission post 131) may be connected by adhesive.

[0048] In step 5, the housing and the central reinforcement are manufactured. In some embodiments, the housing and the central reinforcement may be manufactured using metallic or non-metallic materials. In some embodiments, the housing structure may be formed using methods such as machining, etching, etc.

[0049] In step 6, the vibrating unit (or called the vibrating membrane assembly) is manufactured. In some embodiments, a mold may be used to position the housing and the central reinforcement, and a hot press molding or injection molding process may be used to form the housing, the central reinforcement and the vibrating membrane into one assembly. The adhesion between the vibrating membrane and the housing and the central reinforcement can be achieved by adhesive, i.e. by intermolecular force.

[0050] In step 7, the speaker is assembled. In some embodiments, the driving unit and the diaphragm assembly may be positioned by a positioning jig, respectively, and corresponding adhesives may be applied between the vibration transmission structure and the diaphragm, and between the housing and the back plate, to realize adhesive assembly of the driving unit and the diaphragm assembly.

[0051] FIG. 7 is an exemplary block diagram of a vibration unit according to some embodiments of the present disclosure.

[0052] As shown in FIG. 7, the vibration unit 700 (or called a vibration membrane assembly) may include a vibration membrane 710 and a central reinforcing part 720. In some embodiments, the central reinforcing part 720 may be located in a central region of the vibration membrane 710. For example, the central reinforcing part 720 may be attached to a surface of the central region of the vibration membrane 710. In some embodiments, the connection manner between the vibration membrane 710 and the central reinforcing part 720 may include bonding (e.g., bonding with an adhesive), welding, riveting, integral molding, and the like. In some embodiments, the vibration membrane assembly 700 may be connected to another member of the speaker (e.g., the housing 140) via the vibration membrane 710 (e.g., the fixing part 711). In some embodiments, the connection manner between the vibration membrane 710 and the housing of the speaker may be bonding (e.g., bonding with an adhesive).

[0053] In some embodiments, the diaphragm 710 may include a fixed portion 711, a folded portion 712, and a central portion 713. The diaphragm 710 may be connected to a housing of a speaker via the fixed portion 711, and the folded portion 712 may be located between the fixed portion and the central portion. As shown in FIG. 7, the fixed portion 711, the folded portion 712, and the central portion 713 may be connected in sequence from the outside to the inside. In some embodiments, the central portion 713 may be located in a central region of the diaphragm 710, the folded portion 712 surrounds the peripheral side of the central portion 713, the inner peripheral side of the folded portion 712 surrounds and is connected to the peripheral side of the central portion 713, and the fixed portion 711 surrounds and is connected to the peripheral side of the folded portion 712 and the outer peripheral side of the folded portion 712. In some embodiments, the projection shape of the central portion 713 along the vibration direction of the diaphragm 710 may be a regular and / or irregular geometric shape, such as a circle, an ellipse, a rectangle, a triangle, a trapezoid, etc. The projection shape of the folding portion 712 along the vibration direction of the diaphragm 710 may be a ring shape that matches the projection shape of the central portion 713. For example, the projection shape of the folding portion 712 along the vibration direction of the diaphragm 710 may be a regular and / or irregular geometric ring shape, such as a circular ring, an elliptical ring, a rectangular ring, a triangular ring, a trapezoidal ring, etc. The projection shape of the fixing portion 711 along the vibration direction of the diaphragm 710 may be a ring shape that matches the projection shape of the folding portion 712. For example, the projection shape of the folding portion 712 along the vibration direction of the diaphragm 710 may be a regular and / or irregular geometric ring shape, such as a circular ring, an elliptical ring, a rectangular ring, a triangular ring, a trapezoidal ring, etc. In some embodiments, the shape of the inner circumference side and the outer circumference side of the fixing part 711 may be the same, for example, both are circular, elliptical, etc. In some embodiments, the shape of the inner circumference side and the outer circumference side of the fixing part 711 may be different in order to facilitate the connection between the diaphragm assembly 700 and the housing of the speaker. For example, as shown in FIG. 7, the shape of the inner circumference side of the fixing part 711 is elliptical, and the shape of the outer circumference side is rectangular.

[0054] In some embodiments, the fixed portion 711 and the central portion 713 may be plate-like or membrane-like structures. In some embodiments, the bent portion 712 may have a curved structure protruding from the plane of the fixed portion 711 (or the central portion 713) connected thereto. In some embodiments, the bent portion 712 may be a planar structure flush with the fixed portion 711 (or the central portion 713). In some embodiments, in the process of the vibration membrane assembly 700 vibrating, the vibration membrane 710 is deformed, and the curved structure of the bent portion 712 tends to become linear in the vibration process, so that the deformation amount generated by the bent portion 712 is larger than that of the fixed portion 711 and the central portion 713, which increases the displacement amount of the vibration membrane assembly 700 in the vibration direction, and further improves the sensitivity of the vibration membrane assembly 700. In some embodiments, the cross-sectional shape of the bent portion 712 in a cross section parallel to the vibration direction may include, but is not limited to, one or more of a circular arc shape, an elliptical arc shape, a broken line shape, a pointed tooth shape, and a square tooth shape.

[0055] In some embodiments, the material of the vibrating membrane 710 may be one or more of organic polymer materials, rubber-based materials, and the like. In some embodiments, the organic polymer materials may include any one or combination of polyimide (PI), polyethylene terephthalate (PET), polyetherimide (PEI), polyetheretherketone (PEEK), and the like. In some embodiments, the material of the vibrating membrane 710 may be a multi-layer composite polymer material. In some embodiments, the materials between each part of the vibrating membrane 710 (e.g., the fixed part 711, the folded part 712, and the central part 713) may be the same or different.

[0056] In some embodiments, the central reinforcing portion 720 may be connected to at least a portion of the central portion 713 to reinforce the vibration of the vibrating membrane 710. In some embodiments, the central reinforcing portion 720 may be located in the central region of the vibrating membrane 710. In some embodiments, the central reinforcing portion 720 may be located in the central portion 713 of the vibrating membrane 710 and attached to the surface of the central portion 713. In some embodiments, the projected shape of the central reinforcing portion 720 along the vibration direction of the vibrating membrane 710 may be a regular and / or irregular geometric shape, such as a circle, an ellipse, a rectangle, a triangle, a trapezoid, etc. In some embodiments, the material of the central reinforcing portion 720 may include a metal material. Exemplary metal materials may include, but are not limited to, stainless steel, aluminum alloy, magnesium-lithium alloy, copper, copper alloy, etc. In some embodiments, the material of the central reinforcing portion 720 may include various anisotropic materials. Exemplary anisotropic materials may include, but are not limited to, carbon fiber, FR4, etc. In some embodiments, the material of the central reinforcement portion 720 may be the same as that of the vibration membrane 710, and exemplary materials may include any one or combination of polyimide (PI), polyethylene terephthalate (PET), polyetherimide (PEI), polyetheretherketone (PEEK), and the like. In some embodiments, the central reinforcement portion 720 may further include a foam composite material or structure. By way of example only, the central reinforcement portion 720 may include a metal film and a foam board, the number of layers of the metal film may be two layers, and the foam board is interposed between the two layers of the metal film. In some embodiments, the material of the metal film may include aluminum alloy, magnesium-lithium alloy, stainless steel, copper, and the like. In some embodiments, the foam board may be a polymer foam board. In some embodiments, the thickness of the foam board may be 0.2 mm to 0.3 mm or more.In some embodiments, the foam composite material or structure may have properties such as low density, high Young's modulus / density ratio, high internal damping, etc., which can improve the acoustic presentation of the central reinforcement portion 720 or speaker.

[0057] In some embodiments, a driving unit of the speaker (e.g., driving unit 110 described above) may be connected to the diaphragm 710 to transmit vibrations to the diaphragm assembly 700, thereby realizing the transmission of mechanical energy from the driving end to the load end of the speaker. In some embodiments, the driving unit of the speaker may be connected to the central reinforcement 720 to transmit vibrations to the diaphragm assembly 700.

[0058] In some embodiments, the central reinforcement 720 may adjust and control the modes of the membrane assembly 700 (or the speaker) in different frequency bands. In some embodiments, the central reinforcement 720 may be connected to the membrane 710 to be part of the membrane assembly 700 and affect the output of the vibration system formed by the membrane assembly 700. In some embodiments, the parameters (e.g., mass, area, etc.) of the central reinforcement 720 may be adjusted to adjust the compliance of the membrane 710 and adjust the output of the vibration system formed by the membrane assembly 700. In some embodiments, the central reinforcement 720 provides mass to the membrane assembly 700 and at the same time provides the membrane assembly 700 with modes in the high frequency range (e.g., greater than 4000 Hz), which may further adjust and control the output of the speaker. In some embodiments, the compliance of the membrane 710 may be adjusted by adjusting the area of ​​the center 713 covered by the central reinforcement 720. For example, with other parameters remaining the same, the larger the area of ​​the center 713 covered by the central reinforcement portion 720, the lower the compliance of the vibration membrane 710, and the smaller the area of ​​the center 713 covered by the central reinforcement portion 720, the higher the compliance of the vibration membrane 710.

[0059] In some embodiments, when the central reinforcement portion 720 is disposed on the surface of the central portion 713, the area of ​​the central reinforcement portion 720 may be smaller than the area of ​​the central portion 713. For example, the central reinforcement portion 720 covers only the surface of the central region of the central portion 713 (e.g., the area of ​​the central reinforcement portion 720 is equal to the area of ​​the central region of the central portion 713 covered by the central reinforcement portion 720), but the edge of the central portion 713 may not be covered by the central reinforcement portion 720. For convenience of explanation, the edge of the central portion 713 that is not covered by the central reinforcement portion 720 may be referred to as the suspension region 7131. That is, the central region of the central portion 713 is covered by the central reinforcement portion 720, the area of ​​the central reinforcement portion 720 is equal to the area of ​​the central region, and the suspension region 7131 is not covered by the central reinforcement portion 720. In some embodiments, an aperture (e.g., aperture 910 shown in FIG. 9) may be provided in the central reinforcement part, and in this case, the area of ​​the suspension region 7131 may be the area of ​​the central part 713 other than the outer contour of the central reinforcement part 720. In some embodiments, the area of ​​the suspension region 7131 may affect the compliance of the diaphragm 710, thereby affecting the mid-frequency (e.g., 1500 Hz to 4000 Hz) mode and the low-frequency (e.g., less than 1500 Hz) mode of the diaphragm assembly 700 or the speaker. In some embodiments, when the area of ​​the suspension region 7131 is large, the compliance of the diaphragm 710 is high, which may cause the first resonance frequency of the frequency response curve of the speaker to move forward (i.e., the first resonance frequency is decreased), thereby improving the low-frequency output of the speaker, and when the area of ​​the suspension region 7131 is small, the compliance of the diaphragm 710 is small, which may improve the mid-frequency output of the speaker. As can be understood, if the area of ​​the suspension region 7131 is large and the low-frequency output of the speaker is improved, a higher mode may appear at the mid-frequency of the frequency response curve of the speaker, forming a dip in the frequency response curve; if the area of ​​the suspension region 7131 is small and the mid-frequency output of the speaker is good, the first resonant frequency of the frequency response curve of the speaker may move backward, and the low-frequency output may decrease.As can be seen from the above discussion, by adjusting the relationship between the area of ​​the suspension region 7131 and the total area of ​​the central portion 713, the compliance of the diaphragm 710 is adjusted, thereby adjusting the output of the diaphragm assembly 700, so that the low and mid frequency output of the speaker is within a reasonable range.

[0060] The area of ​​each member described in the embodiments of this specification may refer to the area of ​​the surface of the corresponding member perpendicular to the vibration direction of the vibrating membrane assembly 700. For example, the total area of ​​the center 713 refers to the area of ​​the surface of the center 713 perpendicular to the vibration direction of the vibrating membrane assembly 700. For example, the total area of ​​the suspension region 7131 refers to the area of ​​the surface of the suspension region 7131 perpendicular to the vibration direction of the vibrating membrane assembly 700. For example, the total area of ​​the central reinforcement portion 720 refers to the area of ​​the surface of the central reinforcement portion 720 perpendicular to the vibration direction of the vibrating membrane assembly 700. For example, the area of ​​the opening installed in the central reinforcement portion 720 below refers to the area of ​​the surface of the opening perpendicular to the vibration direction of the vibrating membrane assembly 700.

[0061] 8 is a comparison diagram of frequency response curves of speakers when the vibration units have different area ratios (i.e., different ratios of the area of ​​the suspension area to the area of ​​the center) according to some embodiments of the present specification. For convenience of explanation, the area of ​​the suspension area 7131 of the center 713 of the vibration membrane assembly (e.g., the vibration membrane assembly 700) is S1, and the total area of ​​the center 713 is S2. m Let S1 and S m The ratio of S1 to S2 is ε (i.e., ε=S1 / S m ).

[0062] As shown in Fig. 8, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of the sound output by the speaker in dB. Curve 810 represents the frequency response curve of the speaker when ε = 0.38, curve 820 represents the frequency response curve of the speaker when ε = 0.29, curve 830 represents the frequency response curve of the speaker when ε = 0.20, curve 840 represents the frequency response curve of the speaker when ε = 0.11, and curve 850 represents the frequency response curve of the speaker when ε = 0. As can be seen by comparing curves 810, 820, 830, 840, and 850, when ε is large (e.g., ε = 0.38), the low frequency output of the speaker is high and there is a noticeable dip in the mid frequency, and when ε is small (e.g., ε = 0), the mid frequency output of the speaker is high and the low frequency output is reduced. In some embodiments, the value of ε may be set in the range of 0.01 to 0.35 to simultaneously guarantee the low-frequency output and the mid-frequency output of the speaker. In some embodiments, the value of ε may be set in the range of 0.05 to 0.3 to widen the mid-low frequency output bandwidth of the speaker and improve the mid-low frequency output effect of the speaker. In some embodiments, the value of ε may be set in the range of 0.1 to 0.25 to reduce the difference between the low-frequency output and the mid-frequency output of the speaker. In some embodiments, the value of ε may be set in the range of 0.15 to 0.2 to further reduce the difference between the low-frequency output and the mid-frequency output.

[0063] In some embodiments, as can be seen from the explanations in Figs. 7 and 8, the mass of the central reinforcement part can affect the output of the vibration unit by affecting the compliance of the vibration membrane, so the parameters (e.g., shape, structure, dimensions) of the central reinforcement part can be adjusted to adjust the mass of the central reinforcement part and adjust the sound pressure level of the sound output by the speaker. For example, by providing a plurality of openings in the central reinforcement part, the mass of the central reinforcement part can be adjusted and the sound pressure level of the sound output by the speaker can be adjusted. Also, for example, by setting the number of the plurality of openings and the dimensions (or called dimensions) of the plurality of openings, the arrangement method, etc., the mass of the central reinforcement part can be adjusted and the frequency response curve of the speaker can be adjusted.

[0064] FIG. 9 is an exemplary configuration diagram of a central reinforcement portion according to some embodiments herein.

[0065] As shown in FIG. 9, the central reinforcing portion 900 may have apertures 910, and the apertures 910 are arranged on the surface of the central reinforcing portion 900. The number of apertures 910 may be a plurality, such as three, four, five, and the like. In some embodiments, the shape of the apertures 910 may be a regular and / or irregular geometric shape, such as a circle, an ellipse, a triangle, a rectangle, a trapezoid, a pentagon, a hexagon, and the like. As shown in FIG. 9, the dimensions of the plurality of apertures 910 (here, referring to the dimensions of a single aperture 910) may be the same, and the intervals (along the longitudinal direction) between two adjacent apertures 910 among the plurality of apertures 910 may be the same. In some embodiments, the number and dimensions of the apertures 910 may be adjusted to adjust the mass of the central reinforcing portion 900. For example, if other conditions are the same (e.g., the outer circumferential dimensions of the central reinforcement portion 900 are the same, and the dimensions of the openings 910 are the same), the greater the number of openings 910, the smaller the mass of the central reinforcement portion 900, and the smaller the number of openings 910, the larger the mass of the central reinforcement portion 900. Also, for example, if other conditions are the same (e.g., the outer circumferential dimensions of the central reinforcement portion 900 are the same, and the number of openings 910 is the same), the greater the dimensions of the openings 910, the smaller the mass of the central reinforcement portion 900, and the smaller the dimensions of the openings 910, the larger the mass of the central reinforcement portion 900. In some embodiments, as can be seen from the above description, by adjusting the number of openings 910 and / or the dimensions of a single opening 910, the total size (or total area) of the multiple openings 910 is actually adjusted to achieve the purpose of adjusting the mass of the central reinforcement portion 900. Based on this, in some embodiments, the ratio between the total area of ​​the plurality of apertures 910 and the area of ​​the central reinforcement part 900 can be adjusted to adjust the area of ​​the central reinforcement part 900, thereby adjusting the output of the vibration unit or the speaker. The area of ​​the central reinforcement part 900 here may refer to the area of ​​the region surrounded by the outer contour of the central reinforcement part 900. In some embodiments, the larger the ratio between the total area of ​​the plurality of apertures 910 and the area of ​​the central reinforcement part 900, the more the speaker's output in the low and mid frequencies can be improved, but the output in the high frequency band can be reduced.Therefore, by setting the ratio of the total area of ​​the multiple openings 910 to the area of ​​the central reinforcement portion 900 within an appropriate range (e.g., 0.01 to 0.35), it is ensured that the speaker has high output performance in each frequency band.

[0066] In some embodiments, the size of each of the plurality of apertures 910 may be different. For example, the size of the plurality of apertures 910 may be gradually increased or decreased. In some embodiments, the interval between two adjacent apertures 910 of the plurality of apertures 910 may be different. For example, the interval between two adjacent apertures 910 may be gradually increased or decreased. For more information on the size and arrangement of the apertures 910, please refer to Figures 11 to 14 and their descriptions. The number, size, arrangement, etc. of the apertures 910 may be set based on actual needs (e.g., the mass of the central reinforcing part 900), and the embodiments of the present specification are not specifically limited thereto.

[0067] 10 is a comparison diagram of the frequency response curves of speakers when the central reinforcement part has different area ratios (i.e., different ratios between the total area of ​​the openings and the area of ​​the central reinforcement part) according to some embodiments of the present specification. For convenience of explanation, the area of ​​the central reinforcement part (e.g., the central reinforcement part 900 in FIG. 9) is set as S q The total area of ​​the multiple openings 910 is S k Let S k and S. q The ratio of k / S q ).

[0068] As shown in Fig. 10, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of the sound output by the speaker in dB. Curve 1010 represents the frequency response curve of the speaker when κ=0. Curve 1020 represents the frequency response curve of the speaker when κ=0.11, curve 1030 represents the frequency response curve of the speaker when κ=0.28, and curve 1040 represents the frequency response curve of the speaker when κ=0.36. As can be seen by comparing curves 1010, 1020, 1030, and 1040, the speaker with multiple apertures 910 can improve the output in each frequency band compared to a speaker with no apertures (i.e., κ=0). Also, as the value of κ increases, the speaker can significantly improve the output in the low and mid frequencies (e.g., less than 5000 Hz), but the output in the high frequencies (e.g., greater than 5000 Hz) decreases. Thus, in some embodiments, the value of κ may be set in the range of 0.01 to 0.35 to improve the output of the speaker in each frequency band. In some embodiments, the value of κ may be set in the range of 0.05 to 0.3 to make the output of the speaker in the high and mid frequencies more flat. In some embodiments, the value of κ may be set in the range of 0.1 to 0.25 to reduce the difference between the high and mid frequency outputs of the speaker. In some embodiments, the value of κ may be set in the range of 0.15 to 0.2 to further reduce the difference between the high and mid frequency outputs of the speaker.

[0069] In some embodiments, the stiffness (or compliance) along the longitudinal direction of the central reinforcement part (e.g., the central reinforcement part 720 as shown in FIG. 7 and the central reinforcement part 900 as shown in FIG. 9) is the same or essentially the same (in this case, a plurality of apertures having the same dimensions are uniformly distributed in the central reinforcement part). Considering that the formation of the central reinforcement part of the vibration unit affects the output of the speaker in the high frequency range (e.g., greater than 5000 Hz), the formation of the central reinforcement part can be adjusted by designing the structure of the central reinforcement part to adjust the high frequency response of the speaker. For example, by setting the dimensional relationship and arrangement relationship between the plurality of apertures in the central reinforcement part, the stiffness along the longitudinal direction of the central reinforcement part can be made different (the structure of the central reinforcement part is also called a variable stiffness structure) (e.g., the stiffness of the central reinforcement part may gradually decrease from the center position (i.e., point A below) to both ends along the longitudinal direction), thereby adjusting the high frequency response of the speaker. Also, for example, the stiffness along the longitudinal direction of the central reinforcement part can be made different by setting the structure of the central reinforcement part (e.g., width, thickness along the vibration direction), etc.

[0070] FIG. 11 is an exemplary diagram of a central reinforcement portion according to some embodiments herein.

[0071] 11, the central reinforcement portion 1100 may include a plurality of apertures, the dimensions of the apertures and / or the spacing between two adjacent apertures may be different, and the plurality of apertures may be distributed non-uniformly in the central reinforcement portion 1100. In some embodiments, the plurality of apertures may be distributed in different regions of the central reinforcement portion 1100. The center (e.g., geometric center) of the central reinforcement portion 1100 is set as a center point, a line segment passing through point A and parallel to the longitudinal direction is set as a first line segment, and a line segment passing through point A and parallel to the width direction is set as a second line segment, and the first line segment and the second line segment divide the central reinforcement portion 1100 into four regions, i.e., an upper right region, an upper left region, a lower left region, and a lower right region. In some embodiments, the plurality of apertures distributed in the central reinforcement portion 1100 may include a first set of apertures 1110, a second set of apertures 1120, a third set of apertures 1130, and a fourth set of apertures 1140. The first set of apertures 1110 is distributed in a top right region of the central reinforcement portion 1100, the second set of apertures 1120 is distributed in a top left region of the central reinforcement portion 1100, the third set of apertures 1130 is distributed in a bottom left region of the central reinforcement portion 1100, and the fourth set of apertures 1140 is distributed in a bottom right region of the central reinforcement portion 1100. In some embodiments, an aperture set (e.g., first aperture set 1110, second aperture set 1120, third aperture set 1130, and fourth aperture set 1140) may include multiple apertures, and the multiple apertures in an aperture set may have different sizes and be non-uniformly distributed over the corresponding area.

[0072] To exemplarily explain the multiple apertures in the first aperture set 1110, the first aperture set 1110 may include a first subaperture 1110-1, a second subaperture 1110-2, a third subaperture 1110-3, a fourth subaperture 1110-4, a fifth subaperture 1110-5, and a sixth subaperture 1110-6 arranged in order from the inside (i.e., a position close to point A) to the outside (i.e., a position away from point A). From the first subaperture 1110-1 to the sixth subaperture 1110-6, the dimensions of the subapertures gradually increase (or increase to a threshold dimension and then stop changing the dimensions). 11, the first subaperture 1110-1 has a smaller dimension than the second subaperture 1110-2, which has a smaller dimension than the third subaperture 1110-3, which has a threshold dimension, and the fourth subaperture 1110-4, fifth subaperture 1110-5, and sixth subaperture 1110-6 have the same dimensions as the third subaperture 1110-3. From the first subaperture 1110-1 to the sixth subaperture 1110-6, the spacing between adjacent subapertures gradually decreases (or decreases to a threshold spacing until the spacing stops changing). For example, the distance between the first sub-aperture 1110-1 and the second sub-aperture 1110-2 is larger than the distance between the second sub-aperture 1110-2 and the third sub-aperture 1110-3, and the distance between the second sub-aperture 1110-2 and the third sub-aperture 1110-3 is larger than the distance between the third sub-aperture 1110-3 and the fourth sub-aperture 1110-4. The conditions of the sub-apertures in the second aperture set 1120, the third aperture set 1130, and the fourth aperture set 1140 are basically the same as the conditions of the sub-apertures in the first aperture set 1110. Note that the distance between two adjacent apertures (or sub-apertures) described in the embodiments of this specification refers to the distance between the geometric centers of two adjacent apertures 1310.

[0073] In some embodiments herein, the dimensions of the multiple apertures in the central reinforcement part 1100 and the spacing between two adjacent apertures can be set differently to make the stiffness at different positions of the central reinforcement part 1100 different (i.e., the structure of the central reinforcement part 1100 is a variable stiffness structure), thereby adjusting the high frequency response of the speaker. For example, when multiple apertures are distributed in the central reinforcement part 1100 in the manner shown in Fig. 11, the stiffness of the central reinforcement part 1100 gradually decreases from the central position (i.e., point A) to both ends along the longitudinal direction.

[0074] It should be noted that the method of adjusting the stiffness of the central reinforcement part 1100 by setting the size and / or interval of the openings described in this specification is merely an exemplary description. By adjusting the stiffness of the central reinforcement part 1100 by the method of opening holes, the process can be simplified, and the size and / or interval of the openings can also be adjusted according to different application scenes, making the range of application wider. In some embodiments, the structure of the central reinforcement part 1100 may also be set to a variable stiffness structure by other methods. For example, the stiffness along the longitudinal direction of the central reinforcement part can be made different by setting the structure of the central reinforcement part (e.g., width, thickness along the vibration direction), etc. As a mere example, from the center position to both ends along the longitudinal direction, the thickness of the central reinforcement part 1100 can be gradually decreased, and therefore the stiffness gradually decreases.

[0075] In some embodiments, the spacing between two adjacent apertures among the plurality of apertures of the central reinforcement may be equal, and the size of the aperture may be gradually changed along the longitudinal direction, so that the structure of the central reinforcement is a variable stiffness structure. FIG. 12 is an exemplary configuration diagram of a central reinforcement according to some embodiments of the present specification. As shown in FIG. 12, the central reinforcement 1200 may include a plurality of apertures 1210, and the spacing between two adjacent apertures 1210 among the plurality of apertures 1210 is equal, and the size of each aperture 1210 among the plurality of apertures 1210 is different along the longitudinal direction of the central reinforcement 1200. For example, the size of the aperture 1210 gradually increases from the center position (i.e., point A) to both ends along the longitudinal direction. In such an installation manner, the stiffness of the central reinforcement 1200 gradually decreases from the center position (i.e., point A) to both ends along the longitudinal direction.

[0076] In some embodiments, the size of the multiple apertures of the central reinforcement part may be set to be equal, and the interval between two adjacent apertures may be set to be gradually changed, so that the structure of the central reinforcement part is a variable stiffness structure. FIG. 13 is an exemplary configuration diagram of a central reinforcement part according to some embodiments of the present specification. As shown in FIG. 13, the central reinforcement part 1300 may include multiple apertures 1310, and the size of each of the multiple apertures 1310 is the same, and the interval between two adjacent apertures 1310 in the longitudinal direction of the central reinforcement part 1300 is different. For example, the interval between two adjacent apertures 1310 gradually increases from the center position (i.e., point A) to both ends along the longitudinal direction. In such an installation manner, the stiffness of the central reinforcement part 1300 gradually decreases from the center position (i.e., point A) to both ends along the longitudinal direction. In some embodiments, the two installation manners shown in FIG. 12 and FIG. 13 may be used in combination to adjust the stiffness of the central reinforcement part. In some embodiments, the number of apertures 1310 may vary, for example, the number of apertures 1310 along the direction of the first line segment and / or the second line segment.

[0077] Fig. 14 is a comparison diagram of frequency response curves of speakers with different structures of the central reinforcement part according to some embodiments of the present specification. As shown in Fig. 14, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of the sound output by the speaker in dB. Curve 1410 represents the frequency response curve of a speaker when the central reinforcement portion (e.g., central reinforcement portion 900) has a uniform structure (i.e., the dimensions of the multiple openings are the same and the spacing between two adjacent openings is the same) and the ratio κ of the total area of ​​the multiple openings to the area of ​​the central reinforcement portion is κ=0.11; curve 1420 represents the frequency response curve of a speaker when the central reinforcement portion has a uniform structure and the ratio κ of the total area of ​​the multiple openings to the area of ​​the central reinforcement portion is κ=0.28; and curve 1430 represents the frequency response curve of a speaker when the central reinforcement portion (e.g., central reinforcement portion 1100) has a non-uniform structure (i.e., the dimensions of the multiple openings are different and / or the spacing between two adjacent openings is different) and the ratio κ of the total area of ​​the multiple openings to the area of ​​the central reinforcement portion is κ=0.19. Comparing curve 1410 and curve 1420, as κ increases, the output of the speaker at low frequencies (e.g., less than 1500 Hz) and mid frequencies (e.g., 1500 Hz to 3000 Hz) is significantly improved, but at the same time, the output of the speaker at high frequencies (the frequency band where the central reinforcement provides formation, e.g., 3000 Hz to 4500 Hz) is reduced (e.g., forms a dip), and the output at higher frequencies (e.g., greater than 4500 Hz) is improved. This causes the frequency response curve of the speaker to be non-flat, and the sound pressure level of the sound output by the speaker to fluctuate widely. Therefore, in order to improve the dip in the high frequency band of the speaker and make the frequency response curve of the speaker flatter in a wider frequency range, the central reinforcement can be made a variable stiffness structure, which extends from the center position to both ends along the longitudinal direction and has a gradually decreasing stiffness (corresponding to curve 1430).Comparing the curve 1430 with the curves 1410 and 1420, when the central reinforcement part of the variable stiffness structure has κ=0.19, the speaker corresponding to the curve 1430 has a higher output in the high frequency band (e.g., 3000Hz to 4500Hz) compared to the curve 1410 (κ=0.11), that is, the output in the high frequency band corresponding to the uniform structure decreases with increasing κ, whereas the non-uniform structure can improve the output in the high frequency band at the same time as the value of κ increases. Also, compared to the curve 1420 (κ=0.28), the speaker corresponding to the curve 1430 has a lower output at higher frequencies. Therefore, it can be seen that by making the structure of the central reinforcement part a variable stiffness structure, the speaker can improve the dip formed at high frequencies (i.e., the frequency band where the central reinforcement part provides formation) and avoid having a large output at higher frequencies, thereby making the frequency response curve of the speaker flatter in a wider frequency range.

[0078] In some embodiments, the vibration transmission part includes a coupling elastic structure and a vibration transmission column (e.g., the above-mentioned vibration transmission column 131 and coupling elastic structure 132), and the driving unit (e.g., a piezoelectric beam) is connected to one end of the vibration transmission column via the coupling elastic structure, and the other end of the vibration transmission column is connected to the vibration unit to transmit vibration and vibrate the vibration unit, so that the speaker may radiate sound pressure outward. In some embodiments, when the impedance of the coupling elastic structure matches the impedance of the driving unit and the impedance of the vibration unit, the driving force and driving displacement of the driving unit may be effectively transmitted to the vibration unit. When the impedance of the coupling elastic structure is too small (e.g., the rigidity is too small), the driving force and driving displacement of the driving unit are largely displaced inside the coupling elastic structure, which dissipates energy through heat loss, and the driving force and driving displacement cannot be transmitted to the vibration unit. If the impedance of the coupling elastic structure is too large (e.g., the rigidity is too large), the driving force and driving displacement of the driving unit are restricted to a certain extent inside the coupling elastic structure, and the driving force and driving displacement transmitted to the vibration unit are relatively reduced. Therefore, in the process of transmitting the driving force and driving displacement of the driving unit to the vibration unit, the design of the coupling elastic structure is very important. In some embodiments, the rigidity of the coupling elastic structure is set to ensure that the impedance of the coupling elastic structure matches the impedance of the driving unit and the impedance of the vibration unit, thereby ensuring that the driving force and driving displacement of the driving unit are effectively transmitted to the vibration unit. In some embodiments, the rigidity of the coupling elastic structure may be adjusted by adjusting the dimensions and structure of the coupling elastic structure, and specifically, the description of FIG. 15A to FIG. 18 may be referred to. In some embodiments, the installation of the coupling elastic structure makes it easier to adjust the rigidity of the entire vibration transmission unit, and the rigidity of the vibration transmission unit may be within a predetermined range. For example, if the vibration transmission unit only includes a vibration transmission column, the rigidity of the entire vibration transmission unit may be too large, which is disadvantageous to the vibration transmission unit transmitting vibration. On the other hand, when the vibration transmission part includes a coupling elastic structure, the rigidity of the vibration transmission part can be adjusted by adjusting the number and structure (e.g., dimensions) of the coupling elastic structures, thereby improving the vibration transmission effect of the vibration transmission part.

[0079] FIG. 15A is an exemplary configuration diagram of a coupled elastic structure according to some embodiments of the present disclosure. FIG. 15A shows a coupled elastic structure 1510, a piezoelectric beam 1520 and a vibration transmission column 1530 connected to the coupled elastic structure 1510. The number of the piezoelectric beams 1520 is four, the number of the coupled elastic structures 1510 is eight, and each piezoelectric beam 1520 is correspondingly connected to two coupled elastic structures 1510. In some embodiments, one end (also called a fixed end) of the piezoelectric beam 1520 is connected to a housing of the speaker (e.g., the back plate 170 shown in FIG. 2A-FIG. 2C), and the other end (also called a free end) is connected to one end of the coupled elastic structure 1510, and the other end of the coupled elastic structure 1510 is connected to a vibration unit via a vibration transmission column 1530. The vibration force and vibration displacement of the piezoelectric beam 1520 can be transmitted to the vibration unit via the coupled elastic structure 1510 and the vibration transmission column 1530. In some embodiments, the region where the piezoelectric beam 1520 and the back plate are connected may be referred to as a fixed region, and the region of the piezoelectric beam 1520 other than the fixed region may be referred to as a suspended region. In some embodiments, as shown in FIG. 15A, the free end of each piezoelectric beam 1520 may be connected to the vibration transmitting column 1530 via two coupling elastic structures 1510. In some embodiments, each piezoelectric beam 1520 may be connected to the vibration transmitting column 1530 via two or more coupling elastic structures 1510. For example, the number of coupling elastic structures 1510 to which each piezoelectric beam 1520 is connected may be one, three, four, five, etc. In some embodiments, the material of the coupling elastic structures 1510 may be the same as the material of the substrate. In some embodiments, the material of the coupling elastic structures 1510 may be different from the material of the substrate.

[0080] In some embodiments, the structural shape of the coupled elastic structure 1510 may be elongated (also called a direct-coupled coupled elastic structure). For example, the shape of the coupled elastic structure 1510 may be elongated plate-like. Both ends along the longitudinal direction of the elongated plate-like structure are respectively connected to the free end of the piezoelectric beam 1520 and the vibration transmission column 1530 to transmit the driving force and driving displacement of the piezoelectric beam 1520 to the vibration unit. In some embodiments, the dimensions (e.g., length, thickness) of the coupled elastic structure 1510 affect the stiffness of the coupled elastic structure 1510, and the stiffness of the coupled elastic structure 1510 is adjusted by adjusting the dimensions of the coupled elastic structure 1510, thereby realizing that the impedance of the coupled elastic structure 1510 matches the impedance of the piezoelectric beam 1520 and the impedance of the coupled elastic structure 1510 matches the impedance of the vibration unit.

[0081] FIG. 15B is a schematic diagram of a layered distribution along the vibration direction of a piezoelectric beam according to some embodiments of the present disclosure.

[0082] In some embodiments, the vibration direction of the piezoelectric beam 1520 may be the same as the thickness direction of the piezoelectric beam 1520 (and the coupled elastic structure 1510). To facilitate understanding of the dimensions (e.g., thickness) of the piezoelectric beam 1520 and the dimensions (e.g., thickness) of the coupled elastic structure 1510 that follow, FIG. 15B shows the thickness h of the piezoelectric beam 1520 and the thickness ho of the coupled elastic structure 1510. As shown in FIG. 15B, the piezoelectric beam 1520 may include eight electrode layers 1521 and six piezoelectric layers 1522 (e.g., PZT). The upper and lower halves of the piezoelectric beam 1520 each include four electrode layers 1521 and three piezoelectric layers 1522, with the four electrode layers 1521 and the three piezoelectric layers 1522 alternately distributed, and a substrate layer 1523 is between two adjacent electrode layers 1521 in the upper and lower halves. FIG. 15B is for explaining the thickness h of the piezoelectric beam 1520 and the thickness ho of the coupled elastic structure 1510, and the above description may be referred to for a detailed description of the piezoelectric beam 1520 and its layers.

[0083] In some embodiments, as shown in FIGS. 15A and 15B , the dimensions of the coupled elastic structure 1510 (e.g., the length Lo of the coupled elastic structure 1510 and the thickness ho of the coupled elastic structure 1510) can affect the stiffness of the coupled elastic structure 1510. For example, the greater the length Lo of the coupled elastic structure 1510, the smaller its stiffness, and the greater the thickness ho, the greater its stiffness. On the other hand, if the stiffness of the coupled elastic structure 1510 is too large or too small, the impedance of the coupled elastic structure 1510 may not match the impedance of the piezoelectric beam 1520 and / or the vibration unit. In addition, the dimensions of the piezoelectric beam 1520 (e.g., the length L of the suspension region of the piezoelectric beam 1520 and the thickness ho of the coupled elastic structure 1510) can affect the stiffness of the coupled elastic structure 1510. p The length L of the coupled elastic structure 1510, the thickness ho of the coupled elastic structure 1510, the length L of the suspended region of the piezoelectric beam 1520, and the thickness h of the piezoelectric beam 1520 can also affect the impedance matching between the coupled elastic structure 1510 and the piezoelectric beam 1520 (and the vibration unit). p By rationally setting the relationship between the thickness h of the piezoelectric beam 1520 and the stiffness of the coupled elastic structure 1510, the impedance of the coupled elastic structure 1510 can be matched to the impedance of the piezoelectric beam 1520 and the impedance of the coupled elastic structure 1510 can be matched to the impedance of the vibration unit. In some embodiments, ζ=√(ho / Lo^ 2 ) / √(h / L p ^ 2 ), and the magnitude of ζ can affect whether the impedance of the coupled elastic structure 1510 and the impedance of the piezoelectric beam 1520 and the vibration unit can achieve impedance matching. For example, if ζ is too small, it indicates that the impedance of the coupled elastic structure 1510 is too small, and there is a possibility that the impedance of the coupled elastic structure and the impedance of the piezoelectric beam and the vibration unit form an impedance mismatch.

[0084] 16 is a comparison diagram of frequency response curves of a speaker with different parameters of a coupled elastic structure according to some embodiments of the present disclosure. As shown in FIG. 16, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of the sound output by the speaker in dB. Curve 1610 represents the frequency response curve of the speaker when ζ=0.34, curve 1620 represents the frequency response curve of the speaker when ζ=0.87, curve 1630 represents the frequency response curve of the speaker when ζ=3.5, curve 1640 represents the frequency response curve of the speaker when ζ=7.5, and curve 1650 represents the frequency response curve of the speaker when ζ=40. As shown in FIG. 15A to FIG. 16, when ζ is too small (e.g., ζ=0.34), the impedance of the coupled elastic structure is too small compared to the impedance of the piezoelectric beam and the impedance of the vibration unit, and the impedance of the coupled elastic structure and the impedance of the piezoelectric beam and the vibration unit form an impedance mismatch. In this case, the driving force and driving displacement generated by the piezoelectric beam cannot be effectively transmitted to the vibration unit, and the sound pressure level of the sound output by the speaker is generally low. Therefore, the value of ζ may be in the range of 0.35 or more. When the value of ζ is appropriate (e.g., ζ=0.87), the impedance of the coupled elastic structure 1510 and the impedance of the piezoelectric beam and the vibration unit form an impedance match. In this case, the driving force and driving displacement generated by the piezoelectric beam can be effectively transmitted to the vibration unit, and the sound pressure level of the sound output by the speaker is generally high. When ζ is too large (e.g., ζ=40), the impedance of the coupled elastic structure is too large compared with the impedance of the piezoelectric beam and the impedance of the vibration unit, and the impedance of the coupled elastic structure and the impedance of the piezoelectric beam and the vibration unit form an impedance mismatch. In this case, the coupled elastic structure limits the generation of driving force and driving displacement, causing the sound pressure level of the sound output by the speaker to be relatively low (e.g., compared with the case of ζ=0.87), but higher than the output of the speaker when ζ=0.34, and the overall frequency response curve of the speaker in this case (i.e., curve 1650) is flat.Based on the above description, in some embodiments, in order to improve the sound pressure level of the sound output by the speaker and improve the flatness of the frequency response curve, the value of ζ may be in the range of 0.35 or more. In some embodiments, in order to improve the sound pressure level of the sound output by the speaker, the value of ζ may be in the range of 0.5 to 40. In some embodiments, in order to further improve the sound pressure level of the sound output by the speaker, the value of ζ may be in the range of 0.87 to 38. In some embodiments, in the case of ζ=0.87, the sound pressure level in the mid-high frequency range (e.g., greater than 2500 Hz) is reduced and the frequency response curve is not flat, so the value of ζ may be in the range of 0.87 or more. Therefore, in order to improve the sound pressure level of the entire sound output by the speaker and improve the flatness of the frequency response curve, the value of ζ may be in the range of 3 to 36. In some embodiments, the value of ζ may be in the range of 5 to 34. In some embodiments, in order to improve the sound pressure level of the sound output by the speaker and further improve the flatness of the frequency response curve, the value of ζ may be in the range of 7 to 32. In some embodiments, the value of ζ may be in the range of 10 to 30. In some embodiments, the value of ζ may be in the range of 12 to 28. In some embodiments, the value of ζ may be in the range of 15 to 25.

[0085] Referring to the related description of FIG. 2C, in some embodiments, the bonded elastic structure 132 may use various anisotropic materials such as metal materials, single layer semiconductor materials, multi-layer semiconductor materials, single layer polymer materials, multi-layer composite polymer materials, or multi-layer composite materials of semiconductors and polymers, carbon fiber, FR4, and the like.

[0086] In some embodiments, the coupling elastic structure 132 may use the same material as the vibration transmission column 131. By installing in this manner, the impedance of the coupling elastic structure 132 can be matched with the impedance of the vibration transmission column 131, and the vibration can be transmitted effectively. For example, the material of the coupling elastic structure 132 and the vibration transmission column 131 is the same as the material of the substrate layer (e.g., the substrate layer 1111) of the piezoelectric beam. By using the material of the coupling elastic structure 132 and the vibration transmission column 131 as the material of the substrate layer of the piezoelectric beam, the impedance of the coupling elastic structure 132 and the vibration transmission column 131 can be matched with the impedance of the driving unit 110, and the vibration can be transmitted more effectively. In some embodiments, the coupling elastic structure 132 may use the same material as the vibration transmission column 131, which can further simplify the manufacturing process. In some embodiments, the coupling elastic structure 132 and the vibration transmission column 131 may be manufactured by an integral molding process.

[0087] In some embodiments, the elastic coupling structure 132 uses a different material from the vibration transmission column 131. For example, the material of the elastic coupling structure 132 and / or the vibration transmission column 131 is different from the substrate material of the piezoelectric beam. The use of different materials for the elastic coupling structure 132 and / or the vibration transmission column 131 and the substrate of the piezoelectric beam is advantageous for achieving customization and refinement of the parameters or performance of the speaker. Note that the materials used for the elastic coupling structure 132 and the vibration transmission column 131 may be determined according to actual needs to adapt to different application scenarios.

[0088] In some embodiments, due to the limitations of some conditions (e.g., factors such as the volume of the speaker and the area of ​​the piezoelectric beam), the size of the coupling elastic structure is also limited, and the dimensions of the coupling elastic structure can only be adjusted within an allowable range or a limited space to adjust the stiffness of the coupling elastic structure. When the coupling elastic structure is elongated in a limited space, the adjustment range of the length of the coupling elastic structure is limited, and the adjustment range of the stiffness of the coupling elastic structure is also limited. In some embodiments, by forming a structural shape of the coupling elastic structure, the coupling elastic structure can further adjust the stiffness of the coupling elastic structure in a limited space, and better realize the impedance matching between the coupling elastic structure and the piezoelectric beam and the vibration unit.

[0089] Fig. 17 is another exemplary configuration diagram of a coupled elastic structure according to some embodiments of the present disclosure. As can be seen, compared to Fig. 15A, Fig. 17 only shows one piezoelectric beam 1720, two coupled elastic structures 1710 connected to the piezoelectric beam 1720, and a portion of a vibration transmission post 1730. Fig. 17 also shows a back plate 1740, and a fixed end of the piezoelectric beam 1720 is connected to the back plate 1740.

[0090] In some embodiments, the projection of the coupled elastic structure 1710 along the vibration direction of the piezoelectric beam 1720 may have at least one curved structure (also referred to as a curved coupled elastic structure). As shown in FIG. 17, both ends along the length of the curved structure are connected to the free end of the piezoelectric beam 1720 and the vibration transmission column 1730, respectively, and the curved structure is curved along the width direction toward another curved structure connected to the piezoelectric beam 1720. For example, two coupled elastic structures 1710 connected to the same piezoelectric beam 1720 may be referred to as a first coupled elastic structure 1711 and a second coupled elastic structure 1712, respectively, and both ends along the length of the first coupled elastic structure 1711 and the second coupled elastic structure 1712 are connected to the free end of the piezoelectric beam 1720 and the vibration transmission column 1730, respectively. At the same length position, the curved directions of the first coupled elastic structure 1711 and the second coupled elastic structure 1712 are opposite to each other. As shown in FIG. 17, a structure formed by two coupled elastic structures 1710 connected to the same piezoelectric beam 1720, each of which is bent once (i.e., the first coupled elastic structure 1711 and the second coupled elastic structure 1712 are each bent once), may be referred to as a double-bent coupled elastic structure (or a two-bent coupled elastic structure).

[0091] In some embodiments, the elastic coupling structure 1710 may be configured to be a multi-bend elastic coupling structure, for example, a four-bend elastic coupling structure, a six-bend elastic coupling structure, or an eight-bend elastic coupling structure. Only the four-bend elastic coupling structure is described as an example, and a structure formed by two elastic coupling structures 1710 connected to the same piezoelectric beam 1720 each being bent twice (i.e., the first elastic coupling structure 1711 and the second elastic coupling structure 1712 are each bent twice) may be called a four-bend elastic coupling structure. By configuring the bent elastic coupling structure, the rigidity of the elastic coupling structure can be adjusted in a limited space, and the impedance matching between the elastic coupling structure and the piezoelectric beam and the vibration unit can be better realized, and at the same time, it is advantageous to the miniaturization design of the speaker.

[0092] In addition, the number of bends of the curved joint elastic structure can be reasonably set according to actual needs (e.g., rigidity requirements), and the present specification does not specifically limit the same.

[0093] In some embodiments of the present specification, by setting the shape structure of the coupled elastic structure 1710 to be curved, the length L of the region where the coupled elastic structure 1710 is located can be reduced while ensuring that the impedance of the coupled elastic structure 1710 does not change, thereby providing more space for the piezoelectric beam structure 1720, increasing the driving force generated by the piezoelectric beam structure 1720, and further improving the sound pressure level of the sound output by the speaker. As can be seen, by setting the length Lo of the curved coupled elastic structure 1710 to be larger in the limited region with the length L, the ζ value can be increased, and the sound pressure level of the sound output by the speaker can be further improved.

[0094] As will be understood, when the shape structure of the coupled elastic structure 1710 is curved, the length Lo of the coupled elastic structure 1710 may refer to the length of the path through which the coupled elastic structure 1710 passes (e.g., the path indicated by the arrow in FIG. 17).

[0095] FIG. 18 is a comparison diagram of frequency response curves of speakers when the elastic coupling structures have different shape structures according to some embodiments of the present specification. As shown in FIG. 18, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of the sound output by the speaker in dB. Curve 1810 represents the frequency response curve of a speaker with a direct-coupled elastic coupling structure (e.g., the elastic coupling structure 1510 shown in FIG. 15A), curve 1820 represents the frequency response curve of a speaker with a four-curved elastic coupling structure, and curve 1830 represents the frequency response curve of a speaker with a two-curved elastic coupling structure. Comparing curve 1810 with curve 1820 and curve 1830, the sound pressure level of the sound output by the speaker with the curved elastic coupling structure is higher than that of the direct-coupled elastic coupling structure (especially in the frequency range of about 1500Hz to 3000Hz). As a result, by using a curved coupling elastic structure, it is possible to reduce the length of the area in which the coupling elastic structure is located while ensuring that the impedance of the coupling elastic structure does not change, and at the same time increase the sound pressure level of the sound output by the speaker.

[0096] It should be noted that the manner of adjusting the stiffness of the elastic coupling structure by using the curved design to adjust its impedance is merely an illustrative example. In some embodiments, the stiffness of the elastic coupling structure may be adjusted by combining the direct-coupled elastic coupling structure and the curved elastic coupling structure. In some embodiments, the stiffness of the elastic coupling structure may be adjusted by setting the width of the elastic coupling structure (the direct-coupled elastic coupling structure and / or the curved elastic coupling structure).

[0097] In some embodiments, the structure or dimensions of the piezoelectric beam affect its natural frequency. For example, the thickness h of the piezoelectric beam is positively correlated with the stiffness of the piezoelectric beam, and the length l of the piezoelectric beam is negatively correlated with the stiffness of the piezoelectric beam, and the stiffness of the piezoelectric beam affects its natural frequency. Here, the thickness h may be the thickness dimension of the piezoelectric beam along its vibration direction (e.g., z direction shown in FIG. 4), and the length l may be the length dimension of the piezoelectric beam along its longitudinal direction (e.g., x direction shown in FIG. 4). In some embodiments, the driving unit (e.g., piezoelectric beam) of the speaker may be designed to enhance the driving capacity of the driving unit, optimize the vibration structure of the speaker, and further improve the output sound pressure level of the speaker.

[0098] In some embodiments, a single piezoelectric beam (eg, piezoelectric beam 1520) may be understood as a loaded rectangular plate cantilever beam structure, and the formula for its natural frequency is as follows:

[0099]

number

[0100] In the formula, β n l is a constant term and may be a constant that varies with the value of n. For example, when n=1, β1l=1.875104, when n=2, β2l=4.694091, when n=3, β3l=7.854757, when n=4, β4l=10.995541, and when n=5, β5l=14.1372. E is the material density of the cantilever beam, l is the length of the cantilever beam, and h is the thickness of the cantilever beam.

[0101] As shown in Figures 15A and 15B, in some embodiments, the piezoelectric beam 1520 may include a fixed region and a suspended region. By designing the piezoelectric beam 1520 (e.g., the shape, size, number, etc. of the piezoelectric beam 1520), the vibration mode of the speaker can be adjusted to realize the adjustment and control of the mode of the speaker. As can be seen from Equation (1), the natural frequency of the piezoelectric beam 1520 is related to the material density, length, and thickness of the piezoelectric beam 1520. Therefore, by adjusting the length and / or thickness of the piezoelectric beam 1520, the vibration mode thereof can be adjusted. As shown in Figures 15A and 15B, the length of the suspended region is L p where the thickness of the piezoelectric beam 1520 is h, and the parameter α is a function of the thickness of the piezoelectric beam 1520 (h) and the square of the length of the suspended region (L p 2 ) to the power of 1 / 2. That is,

[0102]

number

[0103] FIG. 19 is a frequency response curve diagram of a speaker corresponding to different parameters α according to some embodiments of the present disclosure. As shown in FIG. 19, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of sound output by the speaker in dB. Curve 1910 represents the frequency response curve of the speaker when parameter α=0.009, curve 1920 represents the frequency response curve of the speaker when parameter α=0.04, curve 1930 represents the frequency response curve of the speaker when parameter α=0.05, curve 1940 represents the frequency response curve of the speaker when parameter α=0.07, and curve 1950 represents the frequency response curve of the speaker when parameter α=0.21. In some embodiments, the parameter α may represent the stiffness of the piezoelectric beam 1520, and a larger α represents a larger stiffness of the piezoelectric beam 1520. As can be seen by comparing the curves 1910 to 1950, when α=0.009, the stiffness of the corresponding piezoelectric beam 1520 is small, and in this case, the frequency of the first resonance peak of the speaker (shown in the dashed circle in FIG. 19) is small, and the output sound pressure level of the speaker 100 is also low. When α is increased, the stiffness of the corresponding piezoelectric beam 1520 is also improved. When α=0.04, the stiffness of the piezoelectric beam 1520 is improved, the frequency of the first resonance peak of the speaker is small, and the low frequency (e.g., less than 1500 Hz) output sound pressure level of the speaker is high, but the mid-high frequency (e.g., greater than 1500 Hz) output sound pressure level is low; when α=0.07, the stiffness of the piezoelectric beam 1520 continues to improve, the frequency of the first resonance peak of the speaker increases, and the mid-high frequency output sound pressure level of the speaker is high, but the low frequency output sound pressure level is low. If α is too large, for example, if α=0.21, the stiffness of the piezoelectric beam 1520 is too large, so that the frequency of the first resonance peak of the speaker is too large, the displacement output of the piezoelectric beam 1520 itself is limited, and the output sound pressure level of the speaker is reduced. In some embodiments, a piezoelectric beam with a large physical parameter α may be used for a situation in which the load impedance is large in a specific frequency band of high frequencies.

[0104] In summary, when the value of α is within the range of 0.009 to 0.21, the speaker has a high output sound pressure level in a wide frequency range. In some embodiments, when the output of the speaker in each frequency band from low frequency to high frequency is taken into consideration comprehensively, the value of α may be in the range of 0.01 to 0.2. In some embodiments, in order to further improve the output of the speaker in each frequency band from low frequency to high frequency, the value of α may be in the range of 0.01 to 0.15. In some embodiments, in order to improve the output sound pressure level of the speaker in the mid-high frequency, α may take a value close to the lower limit value within the range of 0.01 to 0.2. For example, the value of α may be in the range of 0.01 to 0.1. Also, for example, in order to further improve the output sound pressure level of the speaker in the mid-high frequency, the value of α may be in the range of 0.02 to 0.07. Furthermore, for example, in order to improve the output sound pressure level of the speaker in the mid-high frequency and at the same time guarantee the output sound pressure level in the low frequency, the value of α may be in the range of 0.03 to 0.06.

[0105] FIG. 20 is a schematic diagram of a speaker according to some embodiments of the present disclosure.

[0106] 20, the driving ability of the speaker 2000 has a positive correlation with the area of ​​the driving unit, which can be regarded as the total projected area of ​​one or more piezoelectric beams 2010 in the vibration direction of the driving unit. Therefore, by increasing the area of ​​the driving unit, the driving force of the speaker 2000 can be improved, thereby improving the output sound pressure level of the speaker 2000.

[0107] In some embodiments, under the condition that the size of the back plate 2020 of the speaker 2000 is limited, the area occupancy of the driving unit may be increased as much as possible, so that the output of the speaker 2000 may be significantly improved. In some embodiments, in the direction in which the piezoelectric beam 2010 vibrates, the coupled elastic structure occupies the region 1 2030, the region 2 2040 where there is a gap between the adjacent piezoelectric beams 2010, and the region 3 2050 where there is a gap between the piezoelectric beam 2010 and the back plate 2020. Therefore, in the direction in which the piezoelectric beam 2010 vibrates, the area of ​​the driving unit cannot be equal to the area of ​​the internal cavity of the back plate 2020, and the areas occupied by the region 1 2030, the region 2 2040, and the region 3 2050 must be taken into consideration. As for the region 1 2030 occupied by the coupled elastic structure, the area occupied may affect the stiffness of the coupled elastic structure, and thus affect the impedance matching between the impedance of the driving end and the impedance of the load end. For example, if the area of ​​the region 1 2030 occupied by the coupling elastic structure is too large, the stiffness of the coupling elastic structure is too low compared with the driving end and the load end, so that both the driving force and the displacement are concentrated on the coupling elastic structure, which causes the vibration generated by the driving unit to not be effectively transmitted to the vibration unit, and if the area of ​​the region 1 2030 occupied by the coupling elastic structure is too small, the stiffness of the coupling elastic structure is too high compared with the driving end and the load end, so that the mass of the coupling elastic structure increases, thereby limiting the driving force and the displacement output of the driving unit. Regarding the region 2 2040 corresponding to the gap between the adjacent piezoelectric beams 2010 and the region 3 2050 corresponding to the gap between the piezoelectric beam 2010 and the back plate 2020, the size of the areas of these two regions may affect the processing and manufacturing difficulty of the speaker 2000, for example, if the areas of the region 2 2040 and the region 3 2050 are too small, it will cause an increase in the difficulty of the etching process and assembly. Therefore, when the dimensions of the back plate 2020 of the speaker 2000 are fixed, when designing to increase the area of ​​the driving unit, the areas of the area one 2030, the area two 2040 and the area three 2050 need to be considered comprehensively.In some embodiments, in the vibration direction of the piezoelectric beam 2010, a first projected area of ​​the suspension region of the piezoelectric beam 2010 (i.e., the region other than the three regions of region one 2030, region two 2040, and region three 2050) is defined as Sp, a second projected area of ​​the internal cavity of the backplate 2020 is defined as Sc, and the physical quantity β is defined as the ratio of Sp to Sc, i.e.,

[0108]

number

[0109] FIG. 21 is a frequency response curve diagram of a speaker corresponding to different physical parameters β according to some embodiments of the present disclosure. As shown in FIG. 21, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of the sound output by the speaker in dB. Curve 2110 represents the frequency response curve of the speaker when parameter β=0.34, curve 2120 represents the frequency response curve of the speaker when parameter β=0.75, and curve 2130 represents the frequency response curve of the speaker when parameter β=0.92. As shown in curves 2110-2130, when β is 0.34, the overall sound pressure level of the sound output by the speaker is relatively low. When β increases from 0.34 to 0.75 and further to 0.92, the output sound pressure level of the speaker is significantly improved. Therefore, by increasing the ratio β between Sp and Sc, the driving force of the driving unit can be effectively increased, thereby improving the output of the speaker. When β approaches 1, the increase in speaker output decreases as β increases. When β approaches 1, the difficulty of machining and forming the piezoelectric beam 2010 in the internal cavity of the back plate 2020 also increases, and the risk of the piezoelectric beam 2010 contacting the side wall of the cavity also increases.

[0110] In some embodiments, the value of β may be in the range of 0.35 to 0.92 in order to improve the sound pressure level of the speaker. In some embodiments, the value of β may be in the range of 0.4 to 0.9 because a certain clearance space is required for processing and assembling the speaker in the actual production process. In some embodiments, the value of β may be in the range of 0.5 to 0.8 in order to further improve the sound pressure level of the speaker while at the same time reducing the difficulty of processing and forming the piezoelectric beam 2010 in the internal cavity of the back plate 2020 and avoiding the risk of the piezoelectric beam 2010 contacting the side wall of the cavity.

[0111] In some embodiments, the shape of the piezoelectric beam of the speaker plays a significant role in adjusting the mode of the speaker in the mid-high frequency range. Figures 22A and 22B are schematic diagrams of the deformation of piezoelectric beams with different shapes according to some embodiments herein, where Figure 22A is a schematic diagram of the deformation of a rectangular piezoelectric beam 2210, and Figure 22B is a schematic diagram of the deformation of a trapezoidal piezoelectric beam 2220. As shown in Figure 22A, the rectangular piezoelectric beam 2210 has a second mode at mid-frequency range, with small point displacements at both ends and large displacements at the middle part, which causes the displacement of the piezoelectric beam 2210 to be effectively transmitted to the coupling elastic structure 2230 and the vibration transmission pillar (e.g., the vibration transmission pillar 2250 shown in Figure 23) and cannot be transmitted to the vibration unit 2240, and finally causes the output sound pressure level of the speaker in the frequency range to be very low. Thus, in some embodiments, the shape of the piezoelectric beam may be designed to control the output frequency response of the piezoelectric beam of the speaker in the mid-high frequency range, and finally improve the output sound pressure level of the speaker.

[0112] In some embodiments, the piezoelectric beam may have at least two different widths at different positions in its extension direction. That is, the piezoelectric beam may have unequal widths in its extension direction. The extension direction of the piezoelectric beam may be understood as its longitudinal direction. FIG. 23 is a schematic diagram of a trapezoidal piezoelectric beam according to some embodiments herein. As shown in FIG. 23, the width of the piezoelectric beam 2220 gradually changes in its extension direction. By designing the shape of the piezoelectric beam 2220 to have at least two different widths at different positions, the mass and stiffness distribution along the longitudinal direction of the piezoelectric beam 2220 can be adjusted. As shown in FIG. 22B, when the trapezoidal piezoelectric beam 2220 vibrates at a medium frequency, the displacement of the middle part is small, and the displacement of the piezoelectric beam 2220 can be effectively transmitted to the coupling elastic structure 2230 and transmitted to the vibration unit 2240, thereby increasing the vibration of the vibration unit 2240 and improving the output sound pressure level of the speaker.

[0113] In some embodiments, the maximum width of the different widths (e.g., the width of the wide side of the trapezoidal piezoelectric beam 2220) may be defined as Wk, the minimum width of the different widths (e.g., the width of the narrow side of the trapezoidal piezoelectric beam 2220) may be defined as Wz, and the physical quantity θ may be defined as the ratio of the minimum width Wz to the maximum width Wk. That is,

[0114]

number

[0115] By selecting different values ​​of θ, the mass and stiffness distribution along the length of the piezoelectric beam 2220 can be adjusted, thereby improving the output effect of the speaker.

[0116] FIG. 24 is a response curve diagram of a speaker corresponding to different physical parameters θ according to some embodiments of the present disclosure. As shown in FIG. 24, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of the sound output by the speaker in dB. Curve 2410 represents the frequency response curve of the speaker when parameter θ=1, curve 2420 represents the frequency response curve of the speaker when parameter θ=0.82, and curve 2430 represents the frequency response curve of the speaker when parameter θ=0.48. According to curves 2410-2430, when θ is too large (e.g., θ=1) or too small (e.g., θ=0.48), the output of the speaker all generates a deep dip in the mid-frequency band. When the value of θ is appropriate (e.g., θ=0.82), the improvement of the mid-frequency dip is remarkable. Therefore, in some embodiments, to improve the output effect of the speaker in the mid-frequency band, the value of θ may be in the range of 0.5 to 0.99. In some embodiments, to further improve the output effect of the speaker in the mid-frequency band, the value of θ may be in the range of 0.58 to 0.92. In some embodiments, the value of θ may be in the range of 0.6 to 0.9.

[0117] In some embodiments, the minimum width and the maximum width are located at both ends of the piezoelectric beam in the extension direction. As shown in FIG. 23, the piezoelectric beam is trapezoidal, and the minimum width and the maximum width are located at both ends of the piezoelectric beam in the extension direction. In some embodiments, the piezoelectric beam may be designed in other shapes to design the mass and stiffness distribution along the length of the piezoelectric beam to improve the output effect of the speaker. In some embodiments, the shape of the piezoelectric beam includes, but is not limited to, at least one of a rectangle, a trapezoid, and a step shape.

[0118] 25A-25F are schematic diagrams of piezoelectric beams with different shape structures according to some embodiments of the present specification. FIG. 25A is a schematic diagram of a piezoelectric beam 2510 having a trapezoid shape and a wide side of the trapezoid connected to a coupling elastic structure 2520. FIG. 25B is a schematic diagram of a piezoelectric beam 2510 having a trapezoid shape and a narrow side of the trapezoid connected to a coupling elastic structure 2520. FIG. 25C is a schematic diagram of a piezoelectric beam 2510 having a step-shaped structure with two rectangles and a piezoelectric beam 2510 having a step-shaped structure with two rectangles. FIG. 25D is a schematic diagram of a piezoelectric beam 2510 having a staircase-shaped structure with two rectangles and a narrow side of the staircase-shaped structure connected to the coupled elastic structure 2520. FIG. 25E is a schematic diagram of a piezoelectric beam 2510 having a staircase-shaped structure with three rectangles. FIG. 25F is a schematic diagram of a piezoelectric beam 2510 having a staircase-shaped structure with two rectangles and one trapezoid.

[0119] In some embodiments, as shown in FIG. 25A, the piezoelectric beam 2510 may be trapezoidal, and the trapezoid has a wide side connected to the coupled resilient structure 2520 and a narrow side connected to the back plate 2530, and the θ of the trapezoidal piezoelectric beam 2510 shown in FIG. 25A may be different from the θ of the trapezoidal piezoelectric beam 2220 shown in FIG. 23. In some embodiments, as shown in FIG. 25B, the piezoelectric beam 2510 may be trapezoidal, and the trapezoid has a narrow side connected to the coupled resilient structure 2520 and a wide side connected to the back plate 2530. In some embodiments, as shown in FIG. 25C, the piezoelectric beam 2510 may be a combination of a rectangle and a step shape, i.e., the piezoelectric beam 2510 may include two rectangles with different dimensions, and the two rectangles are connected to form a step structure, and the step structure may have a wide side (i.e., the larger rectangle) connected to the coupled resilient structure 2520 and a narrow side (i.e., the smaller rectangle) connected to the back plate 2530. In some embodiments, as shown in Figure 25D, the piezoelectric beam 2510 may be a combination of a rectangle and a step shape, i.e., the piezoelectric beam 2510 may include two rectangles with different dimensions, which are connected to form a step-like structure, with a wider side (i.e., the smaller rectangle) connected to the coupling elastic structure 2520 and a narrower side (i.e., the larger rectangle) connected to the back plate 2530. As shown in Figures 25A-25D, the minimum width and the maximum width are located at both ends of the piezoelectric beam in the extension direction, respectively.

[0120] In some embodiments, the minimum width may be located in the middle region in the extension direction of the piezoelectric beam. Figures 25E to 25F show a situation where the minimum width is located in the middle region in the extension direction of the piezoelectric beam. As shown in Figure 25E, the piezoelectric beam 2510 may include three rectangles, which may include two rectangles with large dimensions and one rectangle with small dimensions, and the three rectangles may be connected in sequence, and the rectangle with small dimensions may be located between the two rectangles with large dimensions, thereby forming a staircase structure, and both ends of the staircase structure (i.e., the two large rectangles) are connected to the connecting elastic structure 2520 and the back plate 2530, respectively. 25F, the piezoelectric beam 2510 may include two rectangles and one trapezoid, the two rectangles may include two rectangles with different dimensions, the two rectangles and the trapezoid may be connected in sequence, the rectangle with a smaller dimension may be located between the rectangle with a larger dimension and the trapezoid, thereby forming a staircase structure, the wide side of the trapezoid may be connected to the small rectangle, and the staircase structure has one end (the large rectangle) connected to the coupling elastic structure 2520 and the other end (the narrow side of the trapezoid) connected to the back plate 2530. In some embodiments, no matter what shape the piezoelectric beam uses, the value of the ratio θ between the minimum width Wz and the maximum width Wk of the piezoelectric beam may still be within the range of 0.5 to 0.99 in order to improve the output effect of the speaker.

[0121] In some embodiments, the number of piezoelectric beams may be designed to adjust the stiffness of the driving unit to improve the mid-frequency mode of the speaker and improve the output effect of the speaker. FIG. 26 is a schematic diagram of a plurality of piezoelectric beams according to some embodiments of the present disclosure. As shown in FIG. 26, in some embodiments, the speaker may include a plurality of piezoelectric beams 2610, and the plurality of piezoelectric beams 2610 may be spaced apart along the width direction. Each piezoelectric beam 2610 includes a fixed region 2611 and a suspended region 2612. The fixed end of each piezoelectric beam 2610 is respectively connected to the back plate at its fixed region 2611, and the free end of each piezoelectric beam 2610 is respectively connected to the coupling elastic structure 2620. The number of piezoelectric beams 2610 may be designed to adjust the stiffness of the driving unit to improve the output effect of the speaker.

[0122] In some embodiments of the present specification, the shape of the piezoelectric beam can be designed to adjust the modes at mid-to-high frequencies of the speaker, effectively adjusting the secondary modes that appear at mid-frequencies of the speaker's piezoelectric beam, thereby improving the dip in the speaker's frequency response.

[0123] As shown in FIGS. 5 to 6, 15A to 15B, etc., the piezoelectric beam includes a piezoelectric layer and an electrode layer. The piezoelectric layer deforms in response to an electrical signal, and the deformation causes the piezoelectric beam to vibrate.

[0124] In some embodiments, by adjusting the distribution of the electrodes (also called electrode layers) of the piezoelectric beam, the mid-frequency modes of the piezoelectric beam can be tuned and controlled to improve the dip in the frequency response of the speaker.

[0125] 27A and 27B are schematic diagrams of deformation of a piezoelectric beam with different electrode distributions according to some embodiments of the present specification, in which, in a projection plane along the vibration direction of the piezoelectric beam 2710, the entire surface of the piezoelectric beam 2710 shown in Fig. 27A is covered with an electrode 2720, and one end portion of the piezoelectric beam 2710 adjacent to a fixed region 2711 is covered with an electrode 2720 shown in Fig. 27B. When the entire surface of the piezoelectric beam 2710 is covered with the electrode 2720 as shown in Fig. 27A, the piezoelectric beam 2710 is curved and deformed at all positions in the longitudinal direction of the piezoelectric beam 2710 when a voltage is applied. 27B, in a projection plane along the vibration direction of the piezoelectric beam 2710, when an electrode is coated on one end (or called a fixed end) portion of the piezoelectric beam 2710 close to the fixed region 2711 and an electrode is not coated on a portion away from the fixed region 2711, only the portion of the piezoelectric beam 2710 covered with the electrode is curved and deformed when a voltage is applied, and the portion not covered with the electrode is not deformed. Therefore, by designing the distribution of the electrodes in the piezoelectric beam 2710, the modes of the piezoelectric beam 2710 in different frequency bands can be adjusted and controlled, thereby improving the output effect of the speaker.

[0126] The expression that the entire surface (or a part) of the piezoelectric beam is covered with electrodes refers to a case where the area of ​​the piezoelectric layer is the same as the area of ​​the substrate layer, and the entire electrode layer (or a part) covers the piezoelectric layer, or a case where the piezoelectric layer and the entire electrode layer (or a part) cover the substrate layer, but is not limited thereto in this specification. For convenience of explanation, the above situations are collectively referred to as the entire surface (or a part) of the piezoelectric beam being covered with electrodes.

[0127] FIG. 28 is a schematic diagram of the distribution of electrodes on a piezoelectric beam according to some embodiments of the present specification, FIG. 29A and FIG. 29B are schematic diagrams of simulated deformations of piezoelectric beams with different electrode distributions according to some embodiments of the present specification, and FIG. 30 is a response curve diagram of a speaker corresponding to the two electrode distributions shown in FIG. 29A and FIG. 29B. FIG. 29A is a schematic diagram of simulated deformations of a piezoelectric beam 2710 covered with an electrode 2720 over the entire length. FIG. 29B is a schematic diagram of simulated deformations of a piezoelectric beam 2710 covered with an electrode 2720 on a portion close to a fixed end. As shown in FIG. 30, the horizontal axis represents frequency in Hz, and the vertical axis represents sound pressure level of the sound output by the speaker in dB. Curve 3010 is a frequency response curve of a speaker when the electrode 2720 is covered over the entire piezoelectric beam 2710, and curve 3020 is a frequency response curve of a speaker when the electrode 2720 is covered over a portion of the piezoelectric beam 2710. Compared with the piezoelectric beam 2710 covered over the entirety with the electrode 2720, the piezoelectric beam 2710 covered over only a portion close to the fixed end with the electrode 2720 can better resolve the situation where a dip appears in the frequency response curve in the mid-frequency range of the speaker (e.g., near 2500 Hz), thereby flattening the frequency response curve of the speaker and improving the output effect of the speaker.

[0128] Therefore, in the projection plane along the vibration direction of the piezoelectric beam 2710, the electrode layer partially covers the piezoelectric layer, which can flatten the frequency response curve of the speaker and improve the output effect of the speaker.

[0129] The installation position of the electrode may be determined according to the actual situation, and the present specification does not limit it much. In some embodiments, as shown in FIG. 28, one end (i.e., free end) of the piezoelectric beam 2710 facing the fixed region 2711 in the extension direction may be connected to the vibration transmitting unit, and the distance between the center of the electrode layer and the fixed region 2711 may be smaller than the distance between the center of the electrode layer and the one end connected to the vibration transmitting unit. In other words, the electrode may be installed at a position close to the fixed end of the piezoelectric beam 2710. In some embodiments, the distance between the center of the electrode layer and the fixed region 2711 may be larger than the distance between the center of the electrode layer and the one end connected to the vibration transmitting unit. In other words, the electrode may be installed at a position away from the fixed end of the piezoelectric beam 2710. For example, the electrode may be installed at a middle stage of the piezoelectric beam 2710.

[0130] In some embodiments, the mode of the piezoelectric beam can be effectively adjusted and controlled by designing the dimensions of the electrodes distributed on the piezoelectric beam. In some embodiments, the relationship between the length dimension of the electrodes distributed on the piezoelectric beam and the length dimension of the piezoelectric beam plays an important role in controlling the mode of the piezoelectric beam. As shown in FIG. 28, the electrode 2720 can be a rectangular electrode, and the length of the electrode 2720 covering the suspended region 2712 of the piezoelectric beam 2710 is defined as L. a , the length of the suspension region 2712 is L p The physical quantity γ is defined as the length L of the electrode covered in the suspension region 2712. a and the length L of the suspension region 2712 p is defined as the ratio of

[0131]

number

[0132] FIG. 31 is a frequency response curve diagram of a speaker corresponding to different physical parameters γ according to some embodiments of the present disclosure. As shown in FIG. 31, when the value of the ratio γ is large (e.g., when γ=1), the length of the electrode 2720 is large, and the low-frequency output sound pressure level of the speaker is large, but the mid-frequency (e.g., around 2500 Hz) has a significant dip. As γ gradually decreases (e.g., γ decreases from 1 to 0.06), the speaker has a constantly increasing dip at the mid-frequency, but at the same time, the low-frequency output decreases. When the ratio γ is too small (e.g., when γ=0.06), the improvement of the mid-frequency dip of the speaker is significant, but the length of the electrode 2720 is too small, so the deformation part of the piezoelectric beam 2710 is too small, and the length of the piezoelectric beam 2710 involved in the generation of the driving force is too small, so the driving force generated by the piezoelectric beam 2710 is too small, and the output sound pressure level of the speaker decreases.

[0133] In some embodiments, the value of γ may range from 0.1 to 0.9 to improve the mid-frequency dip of the speaker while ensuring that the speaker has an increased output sound pressure level at low frequencies. In some embodiments, the value of γ may range from 0.2 to 0.6 to flatten the output of the speaker at mid-frequencies. In some embodiments, the value of γ may range from 0.3 to 0.6 to reduce the difference between the low-frequency output and the mid-frequency output of the speaker. In some embodiments, the value of γ may range from 0.3 to 0.5.

[0134] In some embodiments, the width dimension of the electrode affects the size of the deformation area in the piezoelectric beam, so that by adjusting the width dimension of the electrode in the piezoelectric beam, the driving force generated by the piezoelectric beam can be adjusted and controlled to improve the output effect of the speaker. As shown in FIG. 28, the width of the electrode 2720 in the suspension area 2712 is set to W a , the physical quantity τ is the width W of the electrode 2720 a and the width W of the suspension region of the piezoelectric beam 2710 p may be defined as the ratio of

[0135]

number

[0136] 32 is a frequency response curve diagram of a speaker corresponding to different physical parameters τ, according to some embodiments of the present disclosure. As shown in FIG. 32, as the value of the physical parameter τ increases (e.g., the value of τ gradually increases from 0.2 to 1), the width W of the electrode 2720 a is the width W of the suspended region of the piezoelectric beam 2710 p , and the output sound pressure level of the speaker is gradually improved. In some embodiments, when the length dimension of the electrodes distributed on the piezoelectric beam 2710 is constant (e.g., the value of γ ranges from 0.1 to 0.9), the value of τ may range from 0.3 to 1 to ensure that the speaker has a large output sound pressure level. In some embodiments, the value of τ may range from 0.4 to 1. In some embodiments, the value of τ may range from 0.5 to 1.

[0137] In some embodiments, the electrode layer includes a first region (or called the first electrode) adjacent to the fixed region (or called the fixed end) and a second region (or called the second electrode) adjacent to the coupled elastic structure (or called the free end). In some embodiments, if the width of the second electrode installed adjacent to the free end of the piezoelectric beam is too large, the mode at mid-frequency of the piezoelectric beam will be easily affected by the electrode covering the entire piezoelectric beam, and the mid-frequency dip of the frequency response curve of the speaker will be prominent, and if the width adjacent to the free end of the piezoelectric beam is too small, the area of ​​the region involved in the generation of the driving force of the part of the piezoelectric beam covered by the second electrode will be too small, and the improvement of the output sound pressure level of the speaker will not be significant. Therefore, in some embodiments, the distribution of the electrodes may have a gradient. For example, the width of the first region is larger than the width of the second region. By installing in this way, the vibration form of the piezoelectric beam can be effectively controlled, and the output sound pressure level can be improved while ensuring the improvement of the mid-frequency dip.

[0138] FIG. 33 is a schematic diagram of the distribution of electrodes in a piezoelectric beam according to some embodiments of the present specification. As shown in FIG. 33, a first electrode 3321 having a large width dimension and a second electrode 3322 having a small width dimension may be provided on a piezoelectric beam 3310. The first electrode 3321 and the second electrode 3322 may both have a rectangular structure. Note that FIG. 33 shows only the distribution structure of the electrodes (the first electrode 3321 and the second electrode 3322) in one piezoelectric beam 3310, and the distribution structure of the electrodes in the other piezoelectric beams 3310 may refer to the above distribution structure, and the description thereof will be omitted here.

[0139] In some embodiments, the width of the second electrode 3322 is W af , the width of the suspension region 3312 (or the piezoelectric beam 3310) is W p , the physical quantity μ is the width W of the second electrode 3322 af and the width W of the suspension area 3312 p It may be defined as the ratio of

[0140]

number

[0141] FIG. 34 is a frequency response curve diagram of a speaker corresponding to different physical parameters μ according to some embodiments of the present specification. As shown in FIG. 34, when μ is small, for example, μ=0.01, the mid-high frequency output of the speaker is high, and the dip of the mid-frequency (for example, around 2500 Hz) of the output sound pressure level of the speaker increases, but the mid-low frequency (for example, 800 Hz to 1800 Hz) output of the speaker is small, and when μ is large, for example, μ=0.9, the mid-high frequency output of the speaker is relatively low, but the mid-low frequency output is high. As shown in FIG. 34, in some embodiments, the value of μ may range from 0.01 to 0.89 so that the speaker achieves a high output effect in the entire frequency band. In some embodiments, the value of μ may range from 0.01 to 0.7 to further improve the output effect in the entire frequency band of the speaker. In some embodiments, the value of μ may range from 0.1 to 0.7 to reduce the difference between the mid-low frequency output and the mid-high frequency output of the speaker. In some embodiments, the value of μ may range from 0.1 to 0.7 to reduce the difference between the mid-low frequency output and the mid-high frequency output of the speaker. In some embodiments, the value of μ may be selected according to the demands of different application scenarios. For example, when there is a high demand for mid-high frequencies, the value of μ may be in the range of 0.01 to 0.4, and when there is a high demand for mid-low frequencies, the value of μ may be in the range of 0.4 to 0.9.

[0142] As shown in FIG. 33, in some embodiments, the length of the second electrode 3322 adjacent to the free end of the piezoelectric beam 3310 is L. af , the length of the suspension region 3312 is L p , the physical parameter x is the length L of the second electrode 3322. af and the length L of the suspension region 3312 p It may be defined as the ratio of

[0143]

number

[0144] In some embodiments, the length L of the second electrode 3322 af can affect the length of the region involved in generating the actuation force in the piezoelectric beam 3310, L af The larger L is, the longer the region that can contribute to the generation of the driving force in the piezoelectric beam 3310 becomes, and the larger the driving force generated by the piezoelectric beam 3310 becomes, the higher the output sound pressure level of the speaker becomes. af At the same time, the larger the θ, the closer the mid-frequency deformation of the piezoelectric beam 3310 will be to full electrode coverage, which will result in a more pronounced mid-frequency dip in the speaker's output frequency response curve.

[0145] FIG. 35 is a frequency response curve diagram of a speaker corresponding to different physical parameters x according to some embodiments of the present specification. As shown in FIG. 35, when x is small, for example, when x=0, the situation of the mid-frequency (for example, around 4000 Hz) dip of the speaker can be well improved, so the mid-high frequency output of the speaker is high, but the low frequency output is low; when x is large, for example, when x=0.7, the low frequency output of the speaker is good, but the effect of improving the mid-frequency dip is low, so the mid-high frequency output of the speaker is relatively low. Therefore, in some embodiments, when the output effect of the speaker in the entire frequency band is comprehensively considered, the value of x may be in the range of 0.01 to 0.69. In some embodiments, in order to further improve the output effect of the speaker in the entire frequency band, the value of x may be in the range of 0.1 to 0.5. In some embodiments, in order to reduce the difference between the mid-low frequency output and the mid-high frequency output of the speaker, the value of x may be in the range of 0.2 to 0.45. In some embodiments, the value of x may be selected according to the demands of different application scenarios. For example, when there is a high demand for mid-high frequencies, the value of x may be in the range of 0 to 0.4, and when there is a high demand for mid-low frequencies, the value of x may be in the range of 0.4 to 0.7.

[0146] FIG. 36 is a schematic diagram of another distribution of electrodes in a piezoelectric beam according to some embodiments of the present disclosure. In some embodiments, the electrode structure disposed on the piezoelectric beam 3610 may include a trapezoid and a rectangle. As shown in FIG. 36, the electrode layer includes a first region 3621 (or referred to as a first electrode 3621) adjacent to the fixed region and a second region 3622 (or referred to as a second electrode 3622) adjacent to the coupled elastic structure (or referred to as a free end). The first electrode 3621 may be a rectangle with a large width, and the second electrode 3622 may be a trapezoid with a small width. In some embodiments, the width of the rectangular first electrode 3621 may be the same as the width of the wide side of the trapezoid second electrode 3622. Note that FIG. 36 only shows the distribution structure of the electrodes in one piezoelectric beam, and the distribution structure of the electrodes in the other piezoelectric beams may refer to the above distribution structure, and the description will be omitted here. By combining the rectangular first electrode 3621 and the trapezoidal second electrode 3622, the vibration form of the piezoelectric drive can be effectively controlled, the mid-frequency dip of the speaker can be improved, and the output sound pressure level of the speaker can be increased.

[0147] As shown in FIG. 36, the length of the rectangular first electrode 3621 covering the suspension region 3612 is L aj , the length of the second electrode 3622 is L at , the length of the suspension region 3612 is L p The physical quantity parameter z can be defined as the length L of the first electrode 3621. aj and the length L of the suspension region 3612 p It is defined as the ratio of

[0148]

number

[0149] FIG. 37 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters z according to some embodiments of the present specification. As shown in FIG. 37, as the value of z gradually decreases, for example, as the value of z gradually decreases from 1 to 0.05, the mid-frequency (for example, around 3000 Hz) dip of the speaker shifts to a higher frequency, the sound pressure level at the dip gradually improves, and the low-frequency output decreases as the value of z gradually decreases. In some embodiments, in order to improve the mid-high frequency output of the speaker and at the same time ensure the output effect of the speaker at low frequencies, the value of z may range from 0.05 to 0.9. In some embodiments, in order for the speaker to have a flat output in a wider mid-low frequency range, the value of z may range from 0.05 to 0.6. In some embodiments, in order to ensure the output effect of the speaker at low frequencies and better reduce the impact of the mid-frequency dip on the mid-frequency output of the speaker, the value of z may range from 0.1 to 0.5.

[0150] Continuing to refer to FIG. 36, the width of the narrow side of the second electrode 3622 is set to W a2 , the width of the suspension area 3612 is W p , the physical quantity parameter m is the width W of the narrow side of the second electrode 3622 a2 and the width W of the suspension area 3612 p may be defined as the ratio of

[0151]

number

[0152] FIG. 38 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters m according to some embodiments of the present specification. As shown in FIG. 38, as the value of the physical quantity parameter m gradually increases, for example, as the value of m gradually increases from 0.1 to 1, the low frequency output sound pressure level of the speaker improves, the mid-frequency (for example, around 2500 Hz) dip shifts to a low frequency, and when the value of m is too large (for example, the value of m is 1), the sound pressure level at the dip drops significantly. In some embodiments, the value of m may range from 0.1 to 0.9 to improve the output effect of the speaker in the mid-low frequency band. In some embodiments, the value of m may range from 0.1 to 0.7 to further reduce the influence of the mid-frequency dip on the mid-frequency output of the speaker. In some embodiments, the value of m may range from 0.3 to 0.7 to reduce the influence of the mid-frequency dip on the mid-frequency output of the speaker and at the same time improve the low-frequency output.

[0153] Continuing to refer to FIG. 36, the length of the second electrode 3622 is set to L at The physical quantity parameter y can be defined as the length L of the second electrode 3622. at and the length L of the suspension region 3612 p It is defined as the ratio of

[0154]

number

[0155] FIG. 39 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters y according to some embodiments of the present specification. As shown in FIG. 39, the effect of the physical quantity parameter y on the output sound pressure level of the speaker is the opposite of the effect of the physical quantity parameter z on the output sound pressure level of the speaker. As the value of y gradually increases, for example, as the value of y gradually increases from 0 to 0.95, the mid-frequency (for example, around 2500 Hz) dip of the speaker shifts to a higher frequency, the sound pressure level at the dip gradually improves, and the low frequency output decreases as the value of y gradually increases. In some embodiments, in order to improve the mid-high frequency output of the speaker and at the same time ensure the output effect at the low frequency of the speaker, the value of y may range from 0.1 to 0.95. In some embodiments, in order for the speaker to have a flat output in a wider mid-low frequency range, the value of y may range from 0.3 to 0.95. In some embodiments, the value of y may range from 0.5 to 0.8 to ensure the low frequency output effect of the speaker and better reduce the impact of mid-frequency dips on the mid-frequency output of the speaker.

[0156] FIG. 40 is a schematic diagram of another distribution of electrodes in a piezoelectric beam according to some embodiments of the present specification. As shown in FIG. 40, the structure of the electrode 4020 may be trapezoidal. The trapezoidal electrode 4020 is disposed at a position where a wide side is close to the fixed end of the piezoelectric beam 4010, and a narrow side is disposed at a position where a free end (i.e., one end close to the coupling elastic structure) of the piezoelectric beam 4010 is close to the free end. Note that FIG. 40 only shows the distribution structure of the electrodes in one piezoelectric beam, and the distribution structure of the electrodes in the other piezoelectric beams may refer to the above distribution structure, and the description is omitted here. The installation of the trapezoidal electrode 4020 can effectively control the vibration form of the piezoelectric beam, improve the mid-frequency dip of the speaker, and increase the output sound pressure level of the speaker.

[0157] As shown in FIG. 40, the width of one end of the trapezoidal electrode 4020 adjacent to the elastic coupling structure (also called the width of the narrow side) is W a2’, the width of the suspension region 4012 is W p , the physical quantity parameter μ′ is the width W of the narrow side of the trapezoidal electrode 4020 a2’ and the width W of the suspension area 4012 p may be defined as the ratio of

[0158]

number

[0159] FIG. 41 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters μ' according to some embodiments of the present specification. As shown in FIG. 41, as the value of the physical quantity parameter μ' decreases, for example, as the value of μ' gradually decreases from 1 to 0.005, the mid-frequency (for example, around 2500 Hz) dip of the speaker gradually shifts to a higher frequency, the sound pressure level at the dip gradually improves, and the mid-high frequency output of the speaker improves, and as the value of the physical quantity parameter μ' gradually decreases, the low frequency output of the speaker decreases. In some embodiments, in order to improve the mid-high frequency output of the speaker and at the same time ensure the output effect of the speaker at low frequencies, the value of μ' may range from 0.05 to 0.8. In some embodiments, in order for the speaker to have a flat output in a wider mid-low frequency range, the value of μ' may range from 0.05 to 0.6. In some embodiments, in order to ensure the output effect of the speaker at low frequencies and better reduce the impact of the mid-frequency dip on the mid-frequency output of the speaker, the value of μ' may range from 0.2 to 0.5.

[0160] As shown in FIG. 40, in some embodiments, the length of the trapezoidal electrode 4020 covering the suspended region 4012 is set to L aj1 , the length of the suspension region 4012 is L p , the physical quantity parameter γ' is the length L of the trapezoidal electrode 4020 aj1 and the length L of the suspension region 4012 p may be defined as the ratio of

[0161]

number

[0162] FIG. 42 is a frequency response curve diagram of a speaker corresponding to different physical quantity parameters γ' according to some embodiments of the present specification. As shown in FIG. 42, as the value of γ' increases, for example, as the value of γ' gradually increases from 0.05 to 1, the mid-frequency (for example, around 4000 Hz) dip of the speaker gradually becomes more noticeable (for example, the sound pressure level at the dip decreases), and as the value of γ' gradually increases, the low-frequency output of the speaker increases. In some embodiments, in order to improve the mid-high frequency output of the speaker and at the same time ensure the output effect of the speaker at low frequencies, the value of γ' may be in the range of 0.1 to 0.9. In some embodiments, in order to improve the mid-high frequency output of the speaker and at the same time ensure the output effect of the speaker at low frequencies, the value of γ' may be in the range of 0.1 to 0.7. In some embodiments, in order to improve the mid-high frequency output of the speaker and at the same time ensure the output effect of the speaker at low frequencies, the value of γ' may be in the range of 0.2 to 0.6.

[0163] FIG. 43 is a frequency response curve diagram of a speaker corresponding to different electrode shapes according to some embodiments of the present specification. As shown in FIG. 43, compared with the electrode covering the entire piezoelectric beam, the electrode covering the trapezoidal part and the electrode covering the trapezoidal and rectangular parts can both better realize the adjustment and control of the vibration form of the piezoelectric beam at mid-frequency (e.g., around 2500Hz), improve the mid-frequency dip of the speaker, and improve the output sound pressure level of the speaker. The effect of the electrode covering the trapezoidal and rectangular parts is the highest. Therefore, in order to improve the mid-high frequency output of the speaker and at the same time ensure the output effect of the speaker at low frequency, the distribution structure of the electrode on the piezoelectric beam can be designed as a combination form of trapezoid and rectangle. It should be noted that the distribution structure of the electrode on the piezoelectric beam may be selected and designed according to actual needs, and the present specification is not limited thereto.

[0164] In some embodiments, the electrode layer includes a first region (also referred to as the first electrode) adjacent to the anchoring region, a second region (also referred to as the second electrode) adjacent to the coupling elastic structure, and a third region (also referred to as the third electrode) connecting the first and second regions, the width of the third region being smaller than the widths of the first and second regions.

[0165] FIG. 44 is a schematic diagram of another distribution of electrodes on a piezoelectric beam, according to some embodiments of the present disclosure.

[0166] As shown in FIG. 44, a piezoelectric beam 4410 may be provided with a first electrode 4421, a second electrode 4422 and a third electrode 4423 having different width dimensions, and the first electrode 4421, the second electrode 4422 and the third electrode 4423 are all rectangular structures. The first electrode 4421 having the widest width may be located at one end of the piezoelectric beam 4410 close to the fixed region 4411, the second electrode 4422 having a medium width may be located at one end of the piezoelectric beam 4410 close to the coupled elastic structure 4430, and the third electrode 4423 having the smallest width may be located in the middle region of the piezoelectric beam 4410, i.e., in the longitudinal direction of the piezoelectric beam 4410, the third electrode 4423 is located between the first electrode 4421 and the second electrode 4422, and the first electrode 4421, the second electrode 4422 and the third electrode 4423 form a double-stage structure. Note that Figure 44 only shows the distribution structure of the electrodes (first electrode 4421, second electrode 4422, and third electrode 4423) in one piezoelectric beam 4410, and the distribution structure of the electrodes in other piezoelectric beams may refer to the distribution structure described above, and so a description thereof will be omitted here.

[0167] In some embodiments, if the width and length of the second electrode 4422 adjacent to the free end of the piezoelectric beam 4410 is too large, the vibration mode of the piezoelectric beam 4410 at mid-frequency will be close to the vibration mode of a piezoelectric beam entirely covered with an electrode, resulting in a noticeable mid-frequency dip in the output sound pressure level of the speaker. If the width and length of the second electrode 4422 adjacent to the free end of the piezoelectric beam 4410 is too small, the area of ​​the region of the part of the piezoelectric beam 4410 covered by the second electrode 4422 involved in generating the driving force will be too small, resulting in a less noticeable increase in the output sound pressure level of the speaker.

[0168] In some embodiments, the length of the second electrode 4422 is L af1 , the length of the suspension region 4412 is L p , the physical quantity η is expressed as the length L of the second electrode 4422. af1 and the length L of the suspension region 4412 p may be defined as the ratio of

[0169]

number

[0170] FIG. 45 is a frequency response curve diagram of a speaker corresponding to different physical parameters η according to some embodiments of the present disclosure. As shown in FIG. 45, as η gradually decreases (e.g., η gradually decreases from 1 to 0), the mid-frequency (e.g., around 2500 Hz) dip of the speaker gradually increases, so that the mid-high frequency output of the speaker is good but the low frequency output is reduced. In some embodiments, in order to increase the mid-frequency dip of the speaker and at the same time ensure the low frequency output effect, the value of η may be in the range of 0.1 to 0.8. In some embodiments, in order to better reduce the influence of the mid-frequency dip on the mid-frequency output of the speaker, the value of η may be in the range of 0.1 to 0.6. In some embodiments, in order to further improve the low frequency output while reducing the influence of the mid-frequency dip on the mid-frequency output of the speaker, the value of η may be in the range of 0.2 to 0.5.

[0171] In some embodiments, the width W of the second electrode 4422 af1 If the width W of the second electrode 4422 is too large, it will cause the vibration mode of the piezoelectric beam 4410 at mid-frequency to approach the vibration mode of a fully electrode-coated piezoelectric beam, resulting in a noticeable mid-frequency dip in the speaker. af1 If the width W of the second electrode 4422 is too small, the area of ​​the region of the piezoelectric beam 4410 covered by the second electrode 4422 that is involved in generating the driving force becomes too small, and the improvement in the output sound pressure level of the speaker is not significant. af1 and the width W of the suspension area 4412 p The range of the ratio is determined based on the width of the third electrode 4423 (or the second electrode 3322 shown in FIG. 33). Waf and the width W of the suspension region 4412 (or the suspension region 3312 shown in FIG. 33). p The range of values ​​of the ratio μ to W may be the same as that of af1 and W p The value of the ratio of W to W may range from 0.01 to 0.89. In some embodiments, in order to further improve the output effect of the speaker in the full frequency range, af1 and W p The value of the ratio of W to W may range from 0.01 to 0.7. In some embodiments, to reduce the difference between the low-mid frequency output and the high-mid frequency output of the speaker, af1 and W p The ratio value may range from 0.1 to 0.7. In some embodiments, W can be adjusted to meet the needs of different application scenarios. af1 and W p For example, if there is a high demand for mid-high frequencies, the ratio of W af1 and W p The ratio of W to W may be in the range of 0.01 to 0.4. For example, when there is a high demand for low and mid-frequency components, af1 and W p The ratio may be in the range of 0.4 to 0.9.

[0172] FIG. 46 is a schematic diagram of another distribution of electrodes on a piezoelectric beam, according to some embodiments of the present disclosure.

[0173] In some embodiments, the electrodes installed on the piezoelectric beam may have a special shape. In some embodiments, the second region may be arc-shaped. As shown in FIG. 46, the electrodes installed on the piezoelectric beam 4610 may be double-arc-shaped. That is, in the width direction of the piezoelectric beam 4610, both ends of the electrode 4620 may have arc-shaped grooves. In some embodiments, the shape of the arc-shaped groove may include other arc-shaped structures such as, but not limited to, a circular arc, an elliptical arc, and a double curved arc. Note that FIG. 46 only shows the distribution structure of the electrodes in one piezoelectric beam 4610, and the distribution structure of the electrodes in the other piezoelectric beams may refer to the above distribution structure, and the description will be omitted here.

[0174] 47 is a frequency response curve diagram of a speaker with a double arc electrode and a fully covered electrode, according to some embodiments of the present disclosure. As shown in FIG. 47, compared with the piezoelectric beam with a fully covered electrode, the mid-frequency (e.g., around 3000 Hz) dip of the piezoelectric beam with the double arc electrode is shifted to a higher frequency, and the sound pressure level at the dip is improved. Thus, the speaker with the piezoelectric beam with the double arc electrode can adjust the mid-frequency dip well.

[0175] FIG. 48 is a schematic diagram of an electrode extraction method for a piezoelectric beam according to some embodiments of the present disclosure.

[0176] As shown in Fig. 48, the piezoelectric beam includes multiple piezoelectric layers 4810 that deform in response to an electric signal and vibrate the piezoelectric beam by the deformation. Along the vibration direction of the piezoelectric beam, one electrode layer 4820 (also called electrodes) including a positive electrode layer 4821 and a negative electrode layer 4822 is installed on both sides along the vibration direction of each piezoelectric layer 4810. The positive electrode layer 4821 is connected to the positive pole of a voltage, and the negative electrode layer 4822 is connected to the negative pole of the voltage.

[0177] In some embodiments, for a piezoelectric beam using multiple piezoelectric layers 4810, it is necessary to apply corresponding voltages to the electrodes 4820 of different piezoelectric layers 4810 so that the piezoelectric layers 4810 are deformed by the piezoelectric effect. In this case, it is necessary to simultaneously connect the electrodes 4820 of the multiple layers to the positive pole of the power source, and connect the electrodes of the other multiple layers to the negative pole of the power source. In some embodiments, the electrodes 4820 of each layer can be drawn out by a method such as welding wire, soldering, or bonding the FPC with conductive adhesive. For a piezoelectric beam having a single layer or a small number of piezoelectric layers, this method is quick and simple to operate. However, as the number of piezoelectric layers increases, welding wires to each layer may cause problems such as too many bonding wires, complicated processes, low product yield and stability, and large product dimensions. Thus, the above problems can be effectively improved by designing the electrode drawing method.

[0178] 49A and 49B are schematic diagrams of electrodes attached to a piezoelectric beam according to some embodiments of the present disclosure. FIG. 49A is a schematic diagram of an electrode layer to which a positive voltage is applied (or referred to as a positive electrode layer), and FIG. 49B is a schematic diagram of an electrode layer to which a negative voltage is applied (or referred to as a negative electrode layer). Note that FIG. 49A and FIG. 49B are merely illustrative, and in some embodiments, the positive and negative of the electrodes applied to the electrode layers shown in FIG. 49A and FIG. 49B may be reversed, for example, the one shown in FIG. 49A is an electrode layer to which a negative voltage is applied (or referred to as a negative electrode layer), and the one shown in FIG. 49B is an electrode layer to which a positive voltage is applied (or referred to as a positive electrode layer). In some embodiments, each piezoelectric layer in a piezoelectric beam may include a positive electrode layer and a negative electrode layer, and the positive and negative electrode layers may be located on both sides of the piezoelectric layer along the vibration direction of the piezoelectric beam 4910. 49A and 49B, the piezoelectric beam 4910 may include a fixed region 4911 and a suspended region 4912. In some embodiments, the piezoelectric beam 4910 may be connected to the back plate 4930 at the fixed region 4911, which is fixedly installed and therefore has no or little contribution to providing the driving force. Thus, in some embodiments, the structure of the electrodes can be designed without affecting the vibration of the piezoelectric beam 4910 at the fixed region 4911.

[0179] Taking the negative electrode layer as an example, as shown in FIG. 49B, the negative electrode layer 4920 may include a first electrode 4921 located in the fixed region 4911, a lead structure 4922 located on a side of the piezoelectric beam 4910, and a second electrode 4923 located in the suspension region 4912, and the side of the piezoelectric beam 4910 on which the lead structure 4922 is installed may be a side extending along the width direction of the piezoelectric beam 4910. In some embodiments, for each piezoelectric layer, the first electrode 4921 thereon may lead the second electrode 4923 located in the suspension region 4912 and connect to the lead structure 4922 on the side. In some embodiments, the lead structure 4922 can lead the electrodes of each layer that need to apply the same voltage. For example, the lead structure 4922 of each piezoelectric layer can be in communication with each other to lead each negative electrode layer. Also, for example, the positive electrode layer shown in FIG. 49A may have the same or similar configuration as the electrode layer shown in FIG. 49B, and the positive electrode layer 4920′ shown in FIG. 49A may include a first electrode 4921′, a lead structure 4922′, and a second electrode 4923′, and the lead structures 4922′ of each piezoelectric layer may be in communication with each other to lead each positive electrode layer. That is, two lead structures may be installed on the side of the piezoelectric beam, one of which is electrically connected to the multiple positive electrode layers in the multiple piezoelectric layers, and the other lead structure is electrically connected to the multiple negative electrode layers in the multiple piezoelectric layers. In some embodiments, the electrodes of each layer to which different voltages are applied may not be in communication with each other. For example, when multiple piezoelectric layers are stacked, in a projection plane along the vibration direction of the piezoelectric beam 4910, the first electrode 4921' of each positive electrode layer and the first electrode 4921 of the negative electrode layer may not overlap, and accordingly, the lead structure 4922' of each positive electrode layer and the lead structure 4922 of the negative electrode layer may not overlap, thereby achieving non-conduction between the positive and negative electrodes.

[0180] In some embodiments, the width of each of the lead structures of the positive electrode layer and the lead structure of the negative electrode layer may be smaller than half the width of the piezoelectric beam in the width direction of the piezoelectric beam so that the two lead structures are offset in the width direction of the piezoelectric beam, i.e., the lead structures of each of the positive electrode layer and the lead structures of the negative electrode layer do not overlap in a projection plane along the vibration direction of the piezoelectric beam. As shown in FIG. 49A, in some embodiments, the dimension of half the width of the piezoelectric beam 4910 is W j , the width dimension of the electrode layer coated on the fixed area is W a , the physical quantity parameter WW may be defined as follows:

[0181]

number

[0182] In some embodiments, the value of the physical quantity parameter WW may be 5 μm or more to realize non-conduction between the positive and negative electrodes. In some embodiments, the value of the physical quantity parameter WW may be 10 μm or more to further reduce the risk of conduction between the positive and negative electrodes.

[0183] In some embodiments, the two lead structures may be located on two sides extending along the width of the piezoelectric beam, as shown in Figures 49A and 49B. In some embodiments, the two lead structures may be located on two sides extending along the length of the piezoelectric beam, respectively.

[0184] Figures 50A and 50B are schematic diagrams of piezoelectric beams according to some embodiments herein, where Figure 50A is a schematic diagram of electrode attachment for the two configurations shown in Figures 49A and 49B, Figure 50B is an enlarged view of area C in Figure 50A, Figure 50C is a cross-sectional view of the piezoelectric beam shown in Figure 50A along AA, and Figure 50D is a cross-sectional view of the piezoelectric beam shown in Figure 50A along BB. As shown in Figures 50A to 50D, the first electrode 4921 connects electrode layers in each layer to which a voltage of the same polarity (e.g., a negative voltage) needs to be applied via a lead structure 4922 located on a side edge extending along the width direction of the piezoelectric beam 4910 (or on the side corresponding to the fixed region 4911 in the width direction), and the first electrode 4921' can connect electrode layers in each layer to which a voltage of the same polarity (e.g., a positive voltage) needs to be applied via a lead structure 4922' located on a side edge extending along the width direction of the piezoelectric beam 4910 (or on the side corresponding to the fixed region 4911 in the width direction), and for convenience of explanation, the lead structure 4922 can be referred to as a side negative electrode and the lead structure 4922' can be referred to as a side positive electrode.

[0185] In some embodiments, the first electrode 4921 and the first electrode 4921' may not overlap in a projection plane along the vibration direction of the piezoelectric beam 4910, and accordingly, the side negative electrode and the side positive electrode may not overlap. As shown in FIG. 50C and FIG. 50D, a plurality of negative electrode layers 4920 and a plurality of positive electrode layers 4920' may be provided on the piezoelectric beam 4910 along the vibration direction of the piezoelectric beam 4910 (or the thickness direction of the fixed region 4911), and the negative electrode layer 4920 and the positive electrode layer 4920' may each have a relief area in the projection range of the fixed region 4911. As shown in FIG. 50C, the positive electrode layer 4920' to which a positive voltage needs to be applied is connected to the side positive electrode, and a relief area having a length Lk may be provided between the negative electrode layer 4920 to which a negative voltage needs to be applied and the side positive electrode, so that the negative electrode layer 4920 and the side positive electrode are not conductive. Similarly, as shown in FIG. 50D, a relief region having a length Lk may be provided between the positive electrode layer 4920' and the side negative electrode to which a positive voltage needs to be applied, so that the positive electrode layer 4920' and the side negative electrode are not electrically connected. In some embodiments, the length Lk needs to be within a certain range to ensure that the positive electrode layer 4920' and the negative electrode layer 4920 are only connected to the corresponding side electrode. In some embodiments, the value of Lk may be 2 um or more. In some embodiments, the value of Lk may be 5 um or more. In some embodiments, the value of Lk may be 10 um or more.

[0186] In some embodiments, the connection between the fixed region 4911 of the piezoelectric beam 4910 and the back plate may be made by adhesive, mechanical snap-fit, bonding, or the like, or the electrical lead may be made by bonding wire, fastening, or the like. In some embodiments, to simplify the connection between the piezoelectric beam 4910 and the back plate and avoid the instability problem that exists in the bonding wire, the electrical lead and mechanical connection between the piezoelectric beam 4910 and the back plate may be realized by a bonding finger. In some embodiments, the piezoelectric beam 4910 and the back plate may be electrically led through the bonding finger, and at the same time, the mechanical connection may be reinforced by adhesive. In some embodiments, when the electrical lead and mechanical connection between the piezoelectric beam 4910 and the back plate are realized through the bonding finger, the first electrode 4921 and the first electrode 4921′ disposed on the fixed region 4911 may be the electrical lead bonding finger, respectively. For example, the first electrode 4921 and the first electrode 4921' located on the top surface of the piezoelectric beam 4910 can be electrical lead bonding fingers, respectively, to realize the electrical lead and mechanical connection between the piezoelectric beam 4910 and the back plate.

[0187] FIG. 51A is another schematic diagram of a piezoelectric beam according to some embodiments of the present disclosure. FIG. 51B is an enlarged view of the D region in FIG. 51A. FIG. 51C is a cross-sectional view of the piezoelectric beam shown in FIG. 51A along the AA line. FIG. 51A shows a schematic diagram of the attachment of both positive and negative electrodes for applying positive and negative voltages, respectively. In some embodiments, as shown in FIG. 51A to FIG. 51B, the lead structure 4922′ (or called a side positive electrode) of the positive electrode layer 4920 and the lead structure 4922 (or called a side negative electrode) of the negative electrode layer 4920 may be located on two side edges extending along the longitudinal direction of the piezoelectric beam 4910, respectively. In the projection range of the fixed region 4911, the negative electrode layer 4920 and the positive electrode layer 4920′ may each have a relief region. 51C, a positive electrode layer 4920' to which a positive voltage needs to be applied is connected to the side positive electrode, and a relief area having a length Lk may be provided between a negative electrode layer 4920 to which a negative voltage needs to be applied and the side positive electrode, so that the negative electrode layer 4920 and the side positive electrode are not electrically connected. Similarly, a relief area having a length Lk may be provided between a positive electrode layer 4920' to which a positive voltage needs to be applied and the side negative electrode, so that the positive electrode layer 4920' and the side negative electrode are not electrically connected.

[0188] Although the basic concept has been described above, it is clear to those skilled in the art that the detailed disclosure above is merely presented as an example and does not limit the present specification. Although not explicitly described in this specification, those skilled in the art can make various changes, improvements and modifications to the present application. These changes, improvements and modifications are intended to be suggested by this specification and therefore are within the spirit and scope of the exemplary embodiments of the present specification.

[0189] Also, certain terms are used herein to describe embodiments of the present specification. For example, "one embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the present specification. Thus, it is emphasized and understood that references to "one embodiment" or "one embodiment" or "one alternative embodiment" more than one in various parts of the present specification do not necessarily all refer to the same embodiment. Also, certain features, structures, or characteristics in one or more embodiments of the present specification may be combined as appropriate.

[0190] Additionally, unless expressly stated in the claims, the order of enumeration of processing elements or sequences described herein, the use of alphanumeric characters, or the use of other designations, does not limit the order of steps and methods herein. While the above disclosure describes through various examples what are presently believed to be various useful embodiments of the invention, it should be understood that such details are merely illustrative and that the appended claims are not limited to the disclosed embodiments, but on the contrary are intended to cover all modifications and equivalent combinations that are within the spirit and scope of the embodiments herein. For example, the system assembly described above may be implemented by a hardware device, but may also be implemented as a software-only solution, for example, by installing the described system on an existing server or mobile device.

[0191] Similarly, in the foregoing description of embodiments herein, it should be understood that various features may be grouped together in a single embodiment, figure, or description for the purpose of simplifying the description and facilitating understanding of one or more embodiments of the invention. This method of disclosure, however, should not be interpreted as reflecting an intention that the claimed subject matter requires more features than are recited in each claim. In fact, an embodiment may include fewer than all features of a single embodiment disclosed above.

[0192] In some examples, numbers describing the number of components and attributes are used, and it is to be understood that the numbers describing such examples are modified in some instances by the modifiers "about", "approximately" or "generally". Unless otherwise specified, "about", "approximately" or "generally" indicates that the numbers are allowed to vary by ±20%. Thus, in some examples, all numerical parameters used in the specification and claims are approximations that may vary depending on the characteristics required for a particular example. In some examples, the numerical parameters should be applied with the stated number of significant digits and ordinary rounding techniques. In some examples, the numerical ranges and parameters for determining the ranges are approximations; however, in specific examples, such numerical values ​​are set as precisely as possible.

[0193] All patents, patent applications, published patent applications, and other materials, such as papers, books, specifications, publications, documents, etc., referenced herein are incorporated herein by reference in their entirety, except for prosecution history documents that are inconsistent or inconsistent with the contents of this specification, and documents that may have a limiting effect on the broadest scope of the claims of this specification (now or later related to this specification). In addition, if the explanations, definitions, and / or use of terms in the accompanying documents of this specification are inconsistent or inconsistent with the contents described herein, the explanations, definitions, and / or use of terms in this specification shall control.

[0194] Finally, it should be understood that the embodiments described herein are merely illustrative of the principles of the embodiments herein. Other variations are possible within the scope of the present specification. Thus, by way of example, and not of limitation, alternative configurations of the embodiments herein may be considered consistent with the teachings of the present specification. Thus, the embodiments herein are not limited to the embodiments expressly introduced and described herein. [Explanation of symbols]

[0195] 100 speakers 110 Drive unit 120 Vibration Unit 130 Vibration transmission part 140 Housing 150 Front Cavity 160 Rear Cavity 170 Backboard 180 Attenuation Mesh 121 Vibrating Membrane 122 Central reinforcement 1211 Fixed part 1212 Center 1213 Bending part 131 Vibration transmission column 132 Bonded Elastic Structures 111-1 Fixed area 111-2 Suspension area 1111 Board layer 1112 Piezoelectric layer 1113 Electrode layer 700 Vibration Unit 710 Vibrating Membrane 720 Central reinforcement 713 Center 7131 Suspension area 900 central reinforcement 910 Open hole 1100 Central reinforcement 1510 Bonded Elastic Structure 1520 Piezoelectric Beam 1530 Vibration transmission column 1710 Bonded Elastic Structure 1720 Piezoelectric Beam 1740 Backboard 2000 Speakers

Claims

1. A drive unit that vibrates when driven by an electrical signal; A vibration unit; a vibration transmission section that connects the drive unit and the vibration unit and transmits the vibration to the vibration unit to generate sound that is radiated outward; a housing that accommodates the drive unit, the vibration unit, and the vibration transmission section; Including the speaker.

2. 2. The speaker of claim 1, wherein the driving unit includes a piezoelectric beam, the housing surrounds a cavity, and the piezoelectric beam has a portion fixedly connected to the housing to form a fixed area and another portion suspended and positioned above the cavity to form a suspended area.

3. 3. The loudspeaker according to claim 2, wherein the 1 / 2 power of the ratio of the thickness of the piezoelectric beam to the square of the length of the suspension region is in the range of 0.01 to 0.

2.

4. The speaker of claim 2, characterized in that the suspension region has a first projected area in a vibration direction of the piezoelectric beam, the cavity has a second projected area in the vibration direction of the piezoelectric beam, and a ratio of the first projected area to the second projected area is in the range of 0.35 to 0.

92.

5. The speaker according to claim 2 , wherein the piezoelectric beam has at least two different widths at different positions in its extension direction.

6. 6. The loudspeaker according to claim 5, wherein a ratio of a minimum width to a maximum width of the different widths is within a range of 0.5 to 0.

99.

7. The speaker according to claim 6 , wherein the minimum width and the maximum width are located at both ends of the piezoelectric beam in an extension direction.

8. The speaker according to claim 6 , wherein the minimum width is located in a middle region in an extension direction of the piezoelectric beam.

9. 3. The speaker of claim 2, wherein the piezoelectric beam includes a piezoelectric layer and an electrode layer, the piezoelectric layer deforms in response to the electrical signal, the deformation causing the piezoelectric beam to vibrate, and in a projection plane along a vibration direction of the piezoelectric beam, the electrode layer covers a portion of the piezoelectric layer.

10. The speaker described in claim 9, characterized in that one end of the piezoelectric beam facing the fixed area in its extension direction is connected to the vibration transmission section, and the distance between the center of the electrode layer and the fixed area is smaller than the distance between the center of the electrode layer and the one end connected to the vibration transmission section.

11. The speaker of claim 9, characterized in that in the extension direction of the piezoelectric beam, the ratio of the length of the electrode layer coated on the suspension region to the length of the suspension region is in the range of 0.1 to 0.

9.

12. The loudspeaker according to claim 9, characterized in that the ratio of the width of the electrode layer coated on the suspended area to the width of the suspended area is in the range of 0.3 to 1.

13. the vibration transmission part includes a vibration transmission column and a coupling elastic structure, the driving unit is connected to one end of the vibration transmission column via the coupling elastic structure, and the other end of the vibration transmission column is connected to the vibration unit to transmit vibration; 10. The loudspeaker of claim 9, wherein the electrode layer includes a first region adjacent to the fixed region and a second region adjacent to the coupling elastic structure, the width of the first region being greater than the width of the second region.

14. 14. The loudspeaker of claim 13, wherein the first region and the second region are rectangular electrodes, and the ratio of the width of the second region to the width of the suspended region is in the range of 0.01 to 0.

89.

15. 15. The loudspeaker of claim 14, wherein the ratio between the length of the second region and the length of the suspension region is in the range of 0.01 to 0.

69.

16. 14. The loudspeaker of claim 13, wherein the first region is a rectangular electrode and the second region is a trapezoidal electrode.

17. 17. The loudspeaker according to claim 16, wherein the ratio between the length of the rectangular electrode and the length of the suspended area is in the range of 0.05 to 0.

9.

18. The loudspeaker according to claim 16, characterized in that the ratio between the width of the end of the trapezoidal electrode adjacent to the connecting elastic structure and the width of the suspension region is in the range of 0.1 to 0.

9.

19. 17. The loudspeaker according to claim 16, wherein the ratio between the length of the trapezoidal electrode and the length of the suspended region is in the range of 0.1 to 0.

95.

20. The loudspeaker according to claim 13, characterized in that the electrode layer is a trapezoidal electrode, and the ratio of the width of one end of the trapezoidal electrode adjacent to the connecting elastic structure to the width of the suspension region is in the range of 0.05 to 0.

8.

21. the vibration transmission part includes a vibration transmission column and a coupling elastic structure, the driving unit is connected to one end of the vibration transmission column via the coupling elastic structure, and the other end of the vibration transmission column is connected to the vibration unit to transmit vibration; 10. The speaker of claim 9, wherein the electrode layer includes a first region adjacent to the fixed region, a second region adjacent to the connecting elastic structure, and a third region connecting the first region and the second region, the width of the third region being smaller than the widths of the first region and the second region.

22. 22. The loudspeaker of claim 21, wherein the ratio between the length of the second region and the length of the suspension region is in the range of 0.1 to 0.

8.

23. 22. The loudspeaker of claim 21, wherein the ratio between the width of the second region and the width of the suspension region is in the range of 0.01 to 0.

89.

24. 22. The loudspeaker of claim 21, wherein the second region is arcuate.

25. 3. The speaker of claim 2, characterized in that the piezoelectric beam includes multiple piezoelectric layers that deform in response to the electrical signal, the deformation causing the piezoelectric beam to vibrate, and two lead structures are provided on the sides of the piezoelectric beam, one of which is electrically connected to multiple positive electrode layers in the multiple piezoelectric layers, and the other of which is electrically connected to multiple negative electrode layers in the multiple piezoelectric layers.

26. The speaker of claim 25, characterized in that the two lead structures are staggered in the width direction of the piezoelectric beam, and the difference between half the width of the piezoelectric beam and the width of the electrode layer coated on the fixed area is 5 μm or more.

27. 26. The speaker of claim 25, wherein the two lead structures are located on sides extending along the width direction of the piezoelectric beam, or on two sides extending along the length direction of the piezoelectric beam, respectively.

28. The vibration unit includes: a vibration membrane including a fixed portion, a central portion, and a folded portion, the vibration membrane being connected to the housing via the fixed portion, the folded portion being located between the fixed portion and the central portion; a central reinforcing portion connected to at least a portion of the central portion and reinforcing the vibration of the diaphragm; Including, 2. The speaker of claim 1, wherein a suspension region in the central portion that is not covered by the central reinforcement portion has a first area, the central portion has a second area, and a ratio of the first area to the second area is in a range of 0.01 to 0.

35.

29. 29. The loudspeaker according to claim 28, wherein the central reinforcement portion has an aperture, and the ratio of the area of ​​the aperture to the area of ​​the central reinforcement portion is in the range of 0.01 to 0.

35.

30. 29. The speaker according to claim 28, wherein the rigidity of the central reinforcing portion decreases gradually from the middle to both ends in the longitudinal direction of the central reinforcing portion.

31. 31. The speaker according to claim 30, characterized in that the central reinforcement portion has a plurality of apertures, the distance between two adjacent apertures among the plurality of apertures is the same, and the equivalent dimensions of the plurality of apertures gradually increase from the middle to both ends in the longitudinal direction of the central reinforcement portion.

32. The speaker according to claim 30, characterized in that the central reinforcement portion has a plurality of openings, and in the longitudinal direction of the central reinforcement portion, the distance between two adjacent openings among the plurality of openings gradually decreases from the middle to both ends.

33. the vibration transmission part includes a coupling elastic structure and a vibration transmission column, the driving unit is connected to one end of the vibration transmission column via the coupling elastic structure, and the other end of the vibration transmission column is connected to the vibration unit to transmit vibration; The width Lo and thickness ho of the joint elastic structure, and the length L of the suspension area ｐ and the thickness h of the piezoelectric beam is [0010] 2. The loudspeaker according to claim 1, wherein the following expression is satisfied, and ζ is equal to or greater than 0.

35.

34. 34. A loudspeaker as claimed in claim 33, characterized in that the bonded elastic structure uses the same material as the vibration transmitting posts.

35. 34. A loudspeaker as claimed in claim 33, characterized in that the coupling elastic structure uses a different material than the vibration transmitting posts.

36. 34. A loudspeaker as claimed in claim 33, characterized in that the projection of the coupled elastic structure along the vibration direction of the piezoelectric beam has at least one curved structure.

37. The speaker according to claim 33, wherein an escape groove is provided at an end of the vibration transmission pole.

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