Loudspeaker

Abstract

A loudspeaker (100) comprises a plurality of sound production units (110) arranged at intervals along a first direction, and the plurality of sound production units (110) vibrate along the first direction; the shell (120) is configured to accommodate and support the plurality of sound production units (110), the shell (120) is provided with a plurality of sound outlet holes (121), the shell (120) and the plurality of sound production units (110) define a plurality of acoustic cavities (122), each acoustic cavity (122) is acoustically coupled with at least one sound outlet hole (121) in the shell (120), and each sound production unit (100) comprises a vibrating diaphragm (111) and a driving structure (112) arranged on the vibrating diaphragm (111).

Description

A speaker Technical Field

[0001] This specification relates to the field of acoustic technology, and in particular to a loudspeaker. Background Art

[0002] Audio devices, including open-back headphones, wireless earphones, and audio glasses, are increasingly demanding acoustic performance in the low-frequency range. Existing electromagnetic speakers require a large travel range to achieve sufficient sound pressure levels at low frequencies, resulting in larger device dimensions.

[0003] Therefore, it is necessary to provide a loudspeaker with a small design size and capable of providing sufficient low-frequency output.

[0004] Summary of the Invention

[0005] One of the embodiments of the present specification provides a loudspeaker, comprising: a plurality of sound-emitting units arranged at intervals along a first direction, wherein the plurality of sound-emitting units all vibrate along the first direction; a shell configured to accommodate and support the plurality of sound-emitting units, the shell being provided with a plurality of sound outlets, the shell and the plurality of sound-emitting units forming a plurality of acoustic cavities, each acoustic cavity being acoustically coupled to at least one sound outlet hole on the shell, wherein the plurality of sound-emitting units all include a diaphragm and a driving structure arranged on the diaphragm.

[0006] One of the embodiments of this specification also provides an acoustic output device, comprising: a low-frequency unit and a high-frequency unit, wherein the low-frequency unit comprises the loudspeaker as described above, wherein the intersection of the frequency response curves of the low-frequency unit and the high-frequency unit is within the range of 300Hz-1000Hz. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] This specification will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, like numbers represent like structures, wherein:

[0008] FIG1A is a schematic structural diagram of a speaker according to some embodiments of this specification;

[0009] FIG1B is a cross-sectional view of the speaker shown in FIG1A;

[0010] FIG1C is a first view of a cross section of the loudspeaker shown in FIG1B ;

[0011] FIG2A is a simplified structural diagram of a cross section of a loudspeaker according to some embodiments of this specification;

[0012] FIG2B is a simplified structural diagram of a cross section of a loudspeaker when the diaphragm vibrates according to some embodiments of this specification;

[0013] FIG3A is a schematic diagram of the structure of a fixing ring and electrodes according to some embodiments of this specification;

[0014] FIG3B is a cross-sectional view taken along line AA in FIG3A ;

[0015] FIG4A is a schematic structural diagram of a sound-emitting unit according to some embodiments of this specification;

[0016] FIG4B is a schematic structural diagram of a speaker having one sound unit according to some embodiments of this specification;

[0017] FIG5 is a top view of the speaker shown in FIG4B ;

[0018] FIG6 is a schematic structural diagram of a sound-emitting unit according to some embodiments of this specification;

[0019] FIG7 is a schematic structural diagram of a sound-emitting unit according to other embodiments of this specification;

[0020] FIG8 is a schematic structural diagram of a sound-emitting unit according to yet other embodiments of this specification;

[0021] FIG9 is a schematic structural diagram of a sound-emitting unit according to yet other embodiments of this specification;

[0022] FIG10 is a cross-sectional view of a piezoelectric driving structure according to some embodiments of the present specification;

[0023] FIG11A is a schematic structural diagram of a piezoelectric driving structure before deformation according to some embodiments of this specification;

[0024] FIG11B is a schematic diagram of a piezoelectric drive structure after deformation according to some embodiments of this specification;

[0025] FIG12A is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric driving structure according to some embodiments of this specification;

[0026] FIG12B is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric driving structure according to some embodiments of this specification;

[0027] FIG13A is a schematic diagram of a piezoelectric drive structure before deformation according to some embodiments of this specification;

[0028] FIG13B is a schematic diagram of a piezoelectric drive structure after deformation according to some embodiments of this specification;

[0029] FIG14A is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric driving structure according to some embodiments of this specification;

[0030] FIG14B is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric driving structure according to some embodiments of this specification;

[0031] FIG14C is a schematic diagram illustrating polarization directions of piezoelectric layers in a piezoelectric driving structure according to some embodiments of this specification;

[0032] FIG14D is a schematic diagram of the polarization directions of the piezoelectric layers of the piezoelectric driving structure according to some embodiments of this specification;

[0033] FIG15 is a frequency response curve diagram of a loudspeaker corresponding to different values ​​of β according to some embodiments of this specification;

[0034] FIG16 is a schematic diagram of a quarter structure of a piezoelectric drive structure according to some embodiments of this specification;

[0035] FIG17 is a frequency response curve diagram of a loudspeaker corresponding to different values ​​of α according to some embodiments of this specification;

[0036] FIG18 is a schematic diagram of the arrangement of mass blocks shown in some embodiments of the specification;

[0037] FIG19A is a deformation cloud diagram of a diaphragm without a mass block;

[0038] FIG19B is a deformation cloud diagram of the diaphragm with a mass block;

[0039] FIG20 is a schematic diagram of the arrangement of mass blocks shown in some embodiments of the specification;

[0040] FIG21A is a deformation cloud diagram of a diaphragm without a mass block;

[0041] FIG21B is a deformation cloud diagram of the diaphragm with a mass block;

[0042] FIG22 is a schematic diagram of the arrangement of mass blocks shown in some embodiments of the specification;

[0043] FIG23A is a deformation cloud diagram of a diaphragm without a mass block;

[0044] FIG23B is a deformation cloud diagram of the diaphragm with a mass block;

[0045] FIG24A is a schematic structural diagram of a laminated (10-layer) loudspeaker according to some embodiments of the present specification;

[0046] FIG24B is a frequency response curve diagram of a stacked speaker and a single-layer speaker according to some embodiments of the present specification;

[0047] FIG25 is an exemplary schematic diagram of an acoustic output device according to some embodiments of the present specification;

[0048] FIG26A is an exemplary schematic diagram 1 of an acoustic output device according to some other embodiments of this specification;

[0049] FIG26B is a second exemplary schematic diagram of an acoustic output device according to some embodiments of the present specification;

[0050] FIG27 is an exemplary schematic diagram of an acoustic output device according to yet other embodiments of the present specification;

[0051] FIG. 28 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification.

[0052] Explanation of the accompanying reference numerals: 100, loudspeaker; 110, sound unit; 1101, first sound unit; 1102, second sound unit; 1103, third sound unit; 1104, fourth sound unit; 110n, nth sound unit; 111, diaphragm; 112, driving structure; 1121, planar coil; 1122, magnet; 11221, first magnet; 11222, second magnet; 1123, magnetic plate; 1124, magnetic ring; 1125, piezoelectric driving structure; 1125a, piezoelectric covering area; 1125b, non-piezoelectric covering area; 11251, first electrode layer; 11252, first piezoelectric layer; 11253, second electrode layer; 11254, second piezoelectric layer; 11255, third electrode layer; 11256 , neutral layer; 113, elastic structure; 114, lead; 120, shell; 1201, front shell; 1202, rear shell; 121, sound outlet; 1211, first sound outlet; 1212, second sound outlet; 121i, i-th sound outlet; 121(n+1), n+1-th sound outlet; 1212-1, 1212-2, 1213-1, sub-sound outlet; 122, acoustic cavity; 1221, first acoustic cavity; 1222, second acoustic cavity; 1223, third acoustic cavity; 123, fixing ring; 1231, first fixing ring; 1232, second fixing ring; 130, mass block; 140, damping / dustproof mesh; 200, acoustic output device; 201, first hole portion; 202, second hole portion; 203, third hole portion. DETAILED DESCRIPTION

[0053] To more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this specification. Those skilled in the art can apply this specification to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0054] It should be understood that the terms "system," "device," "unit," and / or "module" used herein are a method for distinguishing different components, elements, parts, portions, or assemblies at different levels. However, if other terms can achieve the same purpose, the terms may be replaced by other expressions.

[0055] As used in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not refer to the singular but also include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0056] Flowcharts are used throughout this specification to illustrate the operations performed by systems according to embodiments of this specification. It should be understood that preceding or following operations do not necessarily need to be performed in exact order. Instead, the steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0057] An embodiment of the present specification provides a loudspeaker comprising a housing and a plurality of sound-emitting units. The plurality of sound-emitting units are spaced apart along a first direction and all vibrate along the first direction. The housing is configured to accommodate and support the plurality of sound-emitting units. The housing is provided with a plurality of sound outlets. The housing and the plurality of sound-emitting units form a plurality of acoustic cavities, each acoustic cavity being acoustically coupled to at least one sound outlet in the housing. The sound-emitting units can generate sound waves, which can be transmitted outward through the acoustic cavity in which the sound-emitting units are located and the sound outlets acoustically coupled to the acoustic cavity. In some embodiments, the plurality of sound-emitting units each comprise a diaphragm and a driving structure disposed on the diaphragm. The driving structure drives the diaphragm to vibrate, and the vibrating diaphragm pushes the air within the acoustic cavity to generate sound waves. The embodiments of the present specification optimize the loudspeaker by disposing a plurality of sound-emitting units spaced apart along the first direction, thereby improving the acoustic output, particularly the low-frequency output, of the loudspeaker while subjecting it to certain volume restrictions. Furthermore, the thickness dimension of the loudspeaker can be adjusted by adjusting the number of sound-emitting units in the first direction, allowing the loudspeaker to flexibly adapt to the usage scenario.

[0058] Figure 1A is a schematic structural diagram of a speaker according to some embodiments of the present disclosure. Figure 1B is a cross-sectional view of the speaker shown in Figure 1A. Figure 1C is a first cross-sectional view of the speaker shown in Figure 1B.

[0059] 1A to 1C , a speaker 100 includes a housing 120 and a plurality of sound emitting units 110 spaced apart along a first direction.

[0060] The first direction described in the embodiment of this specification refers to the thickness direction of the loudspeaker 100, with reference to the z direction shown in FIG1A. The arrangement plane where the sound unit 110 is located is perpendicular to the thickness direction of the loudspeaker 100 (i.e., the first direction). It should be noted that the description of the direction involved in this specification is not limited to the absolute direction, but may also be an approximate direction. For example, a plurality of sound units 110 arranged at intervals along the first direction may also be arranged approximately at intervals along the first direction. For another example, the arrangement plane where the sound unit 110 is located is perpendicular to the first direction, or may also be approximately perpendicular. The approximate direction here refers to a direction that forms a certain angle with the absolute direction (e.g., the first direction), and the angle may range from -30° to 30°.

[0061] The housing 120 is a regular or irregular three-dimensional structure having an internal accommodating cavity. For example, the housing 120 can be a hollow frame structure, including but not limited to regular shapes such as a rectangular frame, a circular frame, a regular polygonal frame, and any irregular shape. The housing 120 is used to accommodate the sound unit 110. In some embodiments, referring to Figures 1A-1C, the housing 120 can be a rectangular frame structure. For ease of description, this specification takes the housing 120 as an example of a rectangular frame structure. In some embodiments, the housing 120 can be made of metal (e.g., stainless steel, copper, aluminum alloy, etc.), plastic (e.g., polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and acrylonitrile-butadiene-styrene copolymer (ABS), etc.), composite materials (e.g., metal-based composite materials or non-metal-based composite materials), epoxy resin, phenolic, ceramic, polyimide, glass fiber (e.g., FR4-glass fiber), semiconductor materials (e.g., silicon, silicon dioxide, silicon nitride, silicon carbide, etc.), etc. or any combination thereof.

[0062] The sound unit 110 is a device for generating sound waves and is located in a housing cavity of the housing 120. In some embodiments, the sound unit 110 includes a diaphragm and a driving structure.

[0063] The driving structure is used to convert an audio signal (for example, an electrical signal containing audio information) into mechanical vibration. In some embodiments, the driving structure includes a piezoelectric layer. The piezoelectric layer can convert the audio signal into mechanical vibration. Due to the inverse piezoelectric effect of the piezoelectric layer, when the electrical signal (audio signal) acts on the piezoelectric layer, the piezoelectric layer will generate mechanical vibration. In some embodiments, the piezoelectric layer can be made of piezoelectric material, and exemplary piezoelectric materials can include piezoelectric ceramics, piezoelectric crystals, piezoelectric polymers (for example, polyvinylidene fluoride), etc. or any combination thereof. In some embodiments, the driving structure can be of any shape, such as a sheet, block, columnar, annular structure, etc. or any combination thereof.

[0064] The diaphragm is a component that converts mechanical vibrations from the drive structure into sound waves. In some embodiments, the diaphragm can generate vibrations along a first direction in response to the vibration of the drive structure, thereby generating sound waves (sound signals). In some embodiments, the drive structure is disposed on the diaphragm. The diaphragm directly responds to the deformation or displacement of the drive structure to generate vibrations, and can drive the air around the diaphragm to vibrate with a larger proportion of the vibration driving force, thereby generating sound waves. In some embodiments, the diaphragm can be a thin film structure with elasticity. For a detailed description of the sound-emitting unit 110, please refer to Figures 4A, 6-9 and their related descriptions.

[0065] When a single sound unit 110 is arranged in the housing cavity of the shell 120 of the speaker 100, the thickness dimension of the speaker 100 is relatively small. By arranging multiple sound units 110 in the housing cavity of the shell 120 and spaced apart along the first direction, the dimension of the thickness direction of the speaker 100 can be flexibly adjusted, and the speaker 100 can obtain a larger low-frequency output while meeting the smaller design dimension. In some embodiments, the number of sound units 110 spaced apart in the first direction can be determined according to actual needs. For example, the number of sound units 110 spaced apart in the first direction is determined according to the requirements for the thickness dimension of the speaker 100. For another example, the number of sound units 110 spaced apart in the first direction is determined according to the requirements for the output sound pressure level.

[0066] In some embodiments, multiple sound-emitting units 110 spaced apart along a first direction divide the housing 120 cavity into multiple acoustic cavities 122 distributed along the first direction. The housing 120 is provided with multiple corresponding sound holes, and each acoustic cavity 122 is acoustically coupled to at least one sound hole in the housing 120, so that each acoustic cavity 122 can communicate with the outside of the speaker 100 to transmit the sound waves generated by the sound-emitting unit 110 outward. As shown in Figures 1B and 1C, n sound-emitting units 110 are spaced apart along the first direction, and the n sound-emitting units 110 include a first sound-emitting unit 1101, a second sound-emitting unit 1102, and so on, and an nth sound-emitting unit 110n. The housing cavity of the shell 120 is divided into n+1 acoustic cavities 122 distributed along the first direction, and n+1 sound holes are correspondingly provided on the shell 120, and the n+1 sound holes 121 include a first sound hole 1211, a second sound hole 1212...the n+1th sound hole 121(n+1). Each acoustic cavity 122 is acoustically coupled with a sound hole 121. In some embodiments, the sound hole 121 is a hole that passes through the shell 120, connecting the acoustic cavity 122 with the outside of the shell 120. In some embodiments, the sound hole 121 can be a hole of regular or irregular shape such as a circle, a rectangle, a triangle, and is not limited to the long strip-shaped hole as shown in Figures 1A-1C.

[0067] In some embodiments, the housing 120 includes a front housing 1201 and a rear housing 1202. Referring to FIG. 1B , the front housing 1201 is the portion of the housing 120 located near the top of the housing 120 along a first direction, while the rear housing 1202 is the portion of the housing 120 located near the bottom of the housing 120 along the first direction. A first acoustic cavity 1221 is formed between the front housing 1201 and its adjacent sound unit 110. The rear housing 1202 forms a second acoustic cavity 1222 with another adjacent sound unit 110. A third acoustic cavity 1223 is formed between two adjacent sound units 110. The structure enclosing the third acoustic cavity 1223 also includes the portion of the housing 120 located between the two adjacent sound units 110. Because the diaphragm can vibrate upward and downward along a first direction in response to the vibration of the driver structure, the sound units 110 can generate sound waves within the acoustic cavities 122 above and below them. These sound waves are transmitted outward through the sound outlet holes 121 acoustically coupled to the corresponding acoustic cavities 122. Therefore, the sound unit 110 adjacent to the front shell 1201 exclusively uses the first acoustic cavity 1221, the sound unit 110 adjacent to the rear shell 1202 exclusively uses the second acoustic cavity 1222, and two adjacent sound units 110 (including the sound unit 110 adjacent to the front shell 1201 and the sound unit 110 adjacent to the rear shell 1202) share the third acoustic cavity 1223 therebetween. Taking the sound unit 110 adjacent to the front shell 1201 as an example, referring to Figures 1B and 1C, the first sound unit 1101 uses the first acoustic cavity 1221 alone, and the first sound unit 1101 and the second sound unit 1102 share the third acoustic cavity 1223 between the first sound unit 1101 and the second sound unit 1102. The sound waves output by the first sound unit 1101 are transmitted outward through the first acoustic cavity 1221 and the third acoustic cavity 1223 between the first sound unit 1101 and the second sound unit 1102.

[0068] In some embodiments, the sound holes 121 corresponding to the first acoustic cavity 1221 are opened upward along the first direction. In some embodiments, the sound holes 121 corresponding to the second acoustic cavity 1222 are opened downward along the first direction. In some embodiments, the sound holes 121 corresponding to the first acoustic cavity 1221, the second acoustic cavity 1222, and the third acoustic cavity 1223 can be opened laterally perpendicular to the first direction. In some embodiments, the laterally opened sound holes 121 can be located on one side along the long side of the speaker 100, or on one side along the short side of the speaker 100. In some embodiments, to prevent the sound waves output by the sound holes 121 corresponding to adjacent acoustic cavities 122 from affecting each other and causing interference, the sound holes 121 corresponding to adjacent acoustic cavities 122 can be staggered. In some embodiments, the sound holes 121 corresponding to adjacent acoustic cavities 122 are respectively located on opposite sides of the shell 120. For example, the sound holes 121 corresponding to adjacent acoustic cavities 122 are respectively located on opposite sides along the long side of the shell 120. In another embodiment, the sound holes 121 corresponding to adjacent acoustic cavities 122 are respectively located on adjacent sides of the shell 120. For example, the sound holes 121 corresponding to one acoustic cavity 122 in the adjacent acoustic cavities 122 are located on one side of the shell 120 along the long side, and the sound holes 121 corresponding to another acoustic cavity 122 in the adjacent acoustic cavity 122 are located on one side of the shell 120 along the short side. In yet another embodiment, the sound holes 121 corresponding to adjacent acoustic cavities 122 are located on the same side of the shell 120, and the sound holes 121 corresponding to adjacent acoustic cavities 122 are respectively arranged close to the two side surfaces of the adjacent shell 120, and the two side surfaces of the shell 120 are relatively distributed. For example, the sound holes 121 corresponding to adjacent acoustic cavities 122 are located on the same side of the shell 120 along the long side, and the sound holes 121 corresponding to adjacent acoustic cavities 122 are respectively arranged close to the opposite sides of the shell 120 along the short side.

[0069] In some embodiments, the housing 120 includes multiple fixing rings 123, which are used to secure the sound unit 110. In some embodiments, the multiple fixing rings 123 are arranged overlappingly along a first direction. The multiple fixing rings 123 are spliced ​​together to form the portion of the housing 120 between the front housing 1201 and the rear housing 1202. The sound outlet 121 is defined in the fixing rings 123. The fixing rings 123 near the front housing 1201 are connected to the front housing 1201, while the fixing rings 123 near the rear housing 1202 are connected to the rear housing 1202.

[0070] Figure 2A is a schematic diagram of a cross-section of a loudspeaker according to some embodiments of this specification. Figure 2B is a schematic diagram of a cross-section of a loudspeaker during diaphragm vibration according to some embodiments of this specification. For ease of illustration, Figures 2A and 2B exemplarily illustrate four sound-emitting units 110.

[0071] 2A-2B , in the first direction, the sound unit 110 is disposed within the fixing ring 123. In some embodiments, in the first direction, the sound unit 110 is disposed in the middle of the fixing ring 123, i.e., the fixing ring 123 is evenly distributed on both sides of the sound unit 110.

[0072] In some embodiments, a first acoustic cavity 1221 can be formed between the front shell 1201 and the first sound unit 1101, a second acoustic cavity 1222 can be formed between the rear shell 1202 and the fourth sound unit 1104, and a third acoustic cavity 1223 can be formed between the first sound unit 1101 and the second sound unit 1102, between the second sound unit 1102 and the third sound unit 1103, and between the third sound unit 1103.

[0073] In some embodiments, the thickness of the first acoustic cavity 1221 and / or the second acoustic cavity 1222 along the first direction is less than the thickness of the third acoustic cavity 1223 along the first direction. It is understandable that, as shown in Figures 2A and 2B, since the first acoustic cavity 1221 and the second acoustic cavity 1222 are respectively formed by a sound unit 110 and the front shell 1201 and the rear shell 1202, while the third acoustic cavity 1223 is formed based on two adjacent sound units 110, and since the fixing rings 123 are evenly distributed on both sides of the sound unit 110, the thickness of the third acoustic cavity 1223 along the first direction is greater than the thickness of the first acoustic cavity 1221 and / or the second acoustic cavity 1222 along the first direction.

[0074] In some embodiments, the vibration of the plurality of sound-emitting units 110 along the first direction may include at least one of the plurality of sound-emitting units 110 vibrating in a vertically upward direction and / or at least one of the plurality of sound-emitting units 110 vibrating in a vertically downward direction. Furthermore, the vibration of the plurality of sound-emitting units 110 along the first direction may include two adjacent sound-emitting units 110 in the plurality of sound-emitting units 110 that share at least one of the plurality of acoustic cavities 122 vibrating in opposite directions. As shown in Figures 2A and 2B, the first sound-emitting unit 1101 vibrates in a vertically downward direction, the second sound-emitting unit 1102 vibrates in a vertically upward direction; the third sound-emitting unit 1103 vibrates in a vertically downward direction, and the fourth sound-emitting unit 1104 vibrates in a vertically upward direction. It should be noted that, under the excitation signal, two adjacent sound-emitting units 110 among the multiple sound-emitting units 110 that share at least one acoustic cavity 122 among the multiple acoustic cavities 122 can vibrate in opposite directions across the entire frequency range to enhance the output sound pressure level of the speaker 100 across the entire frequency range. In some embodiments, under the excitation signal, two adjacent sound-emitting units 110 among the multiple sound-emitting units 110 that share at least one acoustic cavity 122 among the multiple acoustic cavities 122 vibrate in opposite directions within at least a portion of the low-frequency range to enhance the output sound pressure level of the acoustic output device (e.g., acoustic output device 200) including the speaker 100 within at least a portion of the low-frequency range, thereby meeting the current requirement for acoustic output devices to gradually increase the output sound pressure level in the low-frequency range.

[0075] In some embodiments, by controlling the excitation voltages of the plurality of sound-emitting units 110, the phase difference between the excitation voltages of the two sound-emitting units 110 of at least one acoustic cavity 122 is 180°, thereby enabling two adjacent sound-emitting units 110 among the plurality of sound-emitting units 110 that share at least one acoustic cavity 122 among the plurality of acoustic cavities 122 to vibrate in opposite directions in at least a portion of the low-frequency band. Based on the fact that the two adjacent sound-emitting units 110 among the plurality of sound-emitting units 110 that share at least one acoustic cavity 122 among the plurality of acoustic cavities 122 vibrate in opposite directions in at least a portion of the low-frequency band, combined with the design of the sound outlet 121 shown in some embodiments of this specification, the sound pressure level output by a loudspeaker 100 (stacked loudspeaker) having n sound-emitting units 110 can be increased by 20×log compared to the sound pressure level output by a loudspeaker 100 (single-layer loudspeaker) having only one sound-emitting unit 110. 10 (n) times.

[0076] In some embodiments, at least part of the low frequency band may include a frequency band less than 500 Hz. In some embodiments, at least part of the low frequency band may include a frequency band less than 300 Hz. For example, the frequency band may be 50 Hz-100 Hz, 100 Hz-150 Hz, or 150 Hz-280 Hz.

[0077] In some embodiments, each fixing ring 123 has two sound outlet holes 121 formed around its periphery. The two sound outlet holes 121 are respectively coupled to the acoustic cavity 122 on opposite sides of the sound-emitting unit 110. The periphery of the fixing ring 123 can be understood as the four sides of the fixing ring 123. For example, when the speaker 100 is designed as a rectangular parallelepiped structure, the periphery of the fixing ring 123 can include a pair of long sides and a pair of short sides.

[0078] In some embodiments, the sound holes 121 can be relatively arranged on both sides of the fixing ring 123 (e.g., opposite long sides or opposite short sides) or adjacently arranged on both sides of the fixing ring 123 (e.g., adjacent long sides and short sides) to couple with two different acoustic cavities 122 respectively.

[0079] As shown in Figure 2A, the dotted line represents the connection surface of two adjacent fixing rings 123. The first fixing ring 1231 has two sound holes on its circumference, namely the first sound hole 1211 and the sub-sound hole 1212-1. The second fixing ring 1232 has two sound holes on its circumference, namely the sub-sound hole 1212-2 and the sub-sound hole 1213-1. Among them, the sub-sound hole 1212-1 is connected to the sub-sound hole 1212-2, and can form a complete second sound hole 1212 coupled to the acoustic cavity 122. In some embodiments, the multiple fixing rings 123 can also be integrally formed. In this case, the shell 120 can be regarded as including only one fixing ring 123, and the multiple sound units 110 are all arranged in one fixing ring 123.

[0080] In some embodiments, in the first direction, the size of the sound outlet 121 corresponding to the first acoustic cavity 1221 and / or the second acoustic cavity 1222 is smaller than the size of the sound outlet 121 corresponding to the third acoustic cavity 1223. The size of the sound outlet 121 may include, but is not limited to, the height of the sound outlet 121 along the first direction.

[0081] In some embodiments of the present specification, two adjacent sound units 110 among a plurality of sound units 110 that share at least one acoustic cavity 122 among a plurality of acoustic cavities 122 vibrate in opposite directions in at least part of the low-frequency band, and in combination with the design of the sound outlet 121 shown in some embodiments of the present specification, the sound pressure level output by the loudspeaker 100 (laminated loudspeaker) having n sound units 110 can be improved compared to the sound pressure level output by the loudspeaker 100 (single-layer loudspeaker) having only one sound unit 110. Furthermore, by taking advantage of the small thickness of the single-layer sound unit 110, a loudspeaker 100 with a smaller thickness and a large low-frequency output sound pressure level can be realized.

[0082] FIG3A is a schematic structural diagram of a fixing ring and an electrode according to some embodiments of the present disclosure; FIG3B is a cross-sectional view taken along line AA in FIG3A .

[0083] In some embodiments, the shell 120 may include a front shell 1201 and a rear shell 1202, each fixing ring 123 is provided with at least two electrodes, and the at least two electrodes on each fixing ring 123 are respectively connected to the front shell 1201 or the rear shell 1202 through corresponding conductive electrodes.

[0084] In some embodiments, the number of electrodes on each fixing ring 123 includes, but is not limited to, two. For example, based on actual needs, the number of electrodes on each fixing ring 123 may also be three. As shown in Figures 3A-3B, the fixing ring 123 may include two electrodes, namely, electrode E1 and electrode E2.

[0085] In some embodiments, based on at least two electrodes (eg, electrode E1 and electrode E2 ) on each fixing ring 123 , an excitation signal (eg, excitation voltage) can be provided to the sound unit 110 fixed on the fixing ring 123 .

[0086] Conductive electrodes refer to electrode structures that connect corresponding electrodes on each fixing ring 123. As shown in Figure 3B, a first conductive electrode D1 can connect the electrode E1 on each fixing ring 123 to the front shell 1201 or the rear shell 1202, and a second conductive electrode D2 can connect the electrode E2 on each fixing ring 123 to the front shell 1201 or the rear shell 1202.

[0087] In some embodiments, the fixing ring 123 is part of the housing 120 and can be made of the same material as the housing 120. In some embodiments, the fixing ring 123 can include one or more of FR4, FPC, and plastic. The fixing ring 123 is provided with at least two conductive holes extending along a first direction, and at least two electrodes are respectively disposed in corresponding conductive holes. The electrodes corresponding to any two adjacent fixing rings 123 can be electrically connected to each other to form conductive electrodes. Mutual electrical connection refers to electrical connection between the electrodes.

[0088] For example, when the fixing ring 123 is made of FR4 or FPC, the two end faces of the fixing ring 123 can be directly connected through the conductive holes. Then, by applying conductive silver paste, conductive adhesive, or patching, at least two electrodes on each fixing ring 123 can be connected to each other to form corresponding conductive electrodes. For another example, when the fixing ring 123 is made of a resin polymer material such as plastic, metal electrodes can be placed in the conductive holes to achieve mutual conductive connection between the corresponding electrodes of any two connected fixing rings 123 to form conductive electrodes.

[0089] Fig. 4A is a schematic diagram of the structure of a sound unit according to some embodiments of this specification. The sound unit 110 shown in Fig. 4A can be the sound unit 110 included in the speaker 100 in any embodiment of this specification.

[0090] As shown in Figure 4A, the sound unit 110 includes a diaphragm 111 and a driving structure 112, and the driving structure 112 is arranged on the diaphragm 111. Among them, the driving structure 112 includes a piezoelectric driving structure (for example, the piezoelectric driving structure 1125 shown in Figure 10). Due to the inverse piezoelectric effect of piezoelectricity, when the electrical signal (audio signal) acts on the piezoelectric driving structure, the piezoelectric driving structure will generate mechanical vibrations. The circumferential side of the diaphragm 111 is connected to the inner wall of the fixing ring 123 located in the acoustic cavity 122, and covers the internal area of ​​the fixing ring 123 to separate the internal area of ​​the fixing ring 123 into two adjacent acoustic cavities 122 located on opposite sides of the diaphragm 111, namely the front cavity and the rear cavity. The diaphragm 111 receives the vibration of the piezoelectric driving structure and generates vibrations. At this time, the diaphragm 111 can push the air in the front cavity and the rear cavity respectively to generate sound waves. Due to the non-redundant structural design between the diaphragm 111 and the driving structure 112, the diaphragm 111 directly responds to the driving structure 112 to generate vibrations. Compared with an additional vibration transfer unit provided between the driving structure 112 and the diaphragm 111, the speaker 100 involved in this specification can use a larger proportion of the vibration driving force to generate sound signals, thereby improving the output sound pressure level and significantly reducing the overall thickness of the speaker 100.

[0091] In some embodiments, the circumference of the diaphragm 111 is embedded in the inner wall of the fixing ring 123 to achieve connection between the diaphragm 111 and the fixing ring 123. As an example only, the inner wall of the fixing ring 123 is provided with a groove along its circumference, and the circumference of the diaphragm 111 is embedded in the groove to achieve fixation with the fixing ring 123.

[0092] In some embodiments, the driving structure 112 may be a plate-like structure. In some embodiments, the driving structure 112 may be a plate-like structure of regular or irregular shapes such as a circle, an ellipse, a square, a pentagon, a hexagon, an octagon and other polygons. In some embodiments, the driving structure 112 may also be a sheet-like or rod-like structure. For ease of description, this specification takes the driving structure 112 as a square plate-like structure as an example. In some embodiments, as shown in FIG4A , the driving structure 112 is arranged on the side of the diaphragm 111 located in the front cavity, and the side of the diaphragm 111 located in the front cavity is connected to the side of the driving structure 112 close to the rear cavity. In other embodiments, the driving structure 112 is arranged on the side of the diaphragm 111 located in the rear cavity, and the side of the diaphragm 111 located in the rear cavity is connected to the side of the driving structure 112 close to the front cavity. In some other embodiments, the sound-emitting unit 110 may include two diaphragms 111, and the two diaphragms 111 are respectively arranged on both sides of the driving structure 112 along the first direction. One of the diaphragms 111 is located in the front cavity and is connected to the side of the driving structure 112 close to the front cavity; the other diaphragm 111 is located in the rear cavity and is connected to the side of the driving structure 112 close to the rear cavity. In some embodiments, in order to make the driving structure 112 drive the diaphragm 111 more uniformly so that the diaphragm 111 can push the air with a larger vibration amplitude, the driving structure 112 is arranged in the middle area of ​​the diaphragm 111. In some embodiments, while the driving structure 112 is connected to the diaphragm 111, the driving structure 112 is also connected to the fixing ring 123 to avoid the mass of the driving structure 112 affecting the vibration state of the diaphragm 111. In some embodiments, in order to avoid the connection between the driving structure 112 and the fixing ring 123 limiting the vibration of the diaphragm 111, so that the driving structure 112 cannot drive the diaphragm 111 to vibrate, the driving structure 112 is connected to the fixing ring 123 through the elastic structure 113. Specifically, the first end of the elastic structure 113 is connected to the peripheral side of the driving structure 112, and the second end of the elastic structure 113 is connected to the inner wall of the fixing ring 123. In some embodiments, the second end of the elastic structure 113 is embedded in the inner wall of the fixing ring 123 to achieve the connection between the elastic structure 113 and the fixing ring 123 .

[0093] In some embodiments, the speaker 100 may have a sound unit 110. Figure 4B is a schematic structural diagram of a speaker with a sound unit according to some embodiments of this specification. As shown in Figure 4B, the speaker 100 may include a shell 120 and a sound unit 110. The sound unit 110 is arranged in a receiving cavity of the shell 120 perpendicular to the first direction. The shell 120 includes a fixing ring 123, which is a cylindrical structure extending along the first direction and is used to support and fix the sound unit 110. For a detailed description of the sound unit 110 and the connection between the sound unit 110 and the fixing ring 123, please refer to Figure 4A and its related description.

[0094] In some embodiments, the shell 120 further includes a front shell 1201, which is connected to the upper end face of the fixing ring 123 along the first direction. In some embodiments, the front shell 1201 is formed as a plate-like structure having a hole. The hole is a sound hole 121. In some embodiments, the shell 120 further includes a rear shell (not shown in the figure), which is connected to the lower end face of the fixing ring 123 along the first direction. In some embodiments, the rear shell 1202 is formed as a plate-like structure having a hole. The hole is another sound hole 121. The sound unit 110 includes a diaphragm 111 and a driving structure 112. The diaphragm 111 divides the accommodating cavity into a front cavity (i.e., a first acoustic cavity 1221) and a rear cavity (i.e., a second acoustic cavity 1222) located on opposite sides of the diaphragm 111. The diaphragm 111 vibrates in response to the deformation or displacement of the driving structure 112. The vibration of the diaphragm 111 drives the air in the front cavity or the rear cavity to produce fluctuations, that is, sound waves (sound signals). The sound waves can be transmitted outward through the sound outlet 121 set on the front shell 1201 or the rear shell 1202.

[0095] In some embodiments, as shown in FIG4B , the side of the diaphragm 111 located in the front cavity is connected to the side of the driver structure 112 near the rear cavity. In this case, the diaphragm 111 can push the air in the rear cavity to generate sound waves, which are transmitted outward through the sound outlet holes 121 provided on the rear housing 1202. In other embodiments, the side of the diaphragm 111 located in the rear cavity is connected to the side of the driver structure 112 near the front cavity. In this case, the diaphragm 111 can push the air in the front cavity to generate sound waves, which are transmitted outward through the sound outlet holes 121 provided on the front housing 1201.

[0096] In some embodiments, the sound outlet 121 on the front shell 1201 or the rear shell 1202 is dustproofed by encapsulation. In some embodiments, the sound outlet 121 can be dustproofed by using a damping / dustproof mesh 140. In some embodiments, as shown in FIG4B , a single sound unit 110 that is dustproofed can be used as a speaker. In some embodiments, as shown in FIG1A , in a speaker 100 including a plurality of sound units 110 spaced apart along a first direction, a damping / dustproof mesh 140 can be provided on the sound outlet 121 corresponding to each of the plurality of acoustic cavities 122 to achieve dustproof encapsulation. In some embodiments, for the speaker 100 shown in FIG1A , dustproof encapsulation may not be performed between two adjacent sound units 110, so that the front cavity and the rear cavity between the two adjacent sound units 110 are not separated, and an acoustic cavity 122 can be formed. In some embodiments, for the speaker 100 shown in Figure 1A, dust-proof packaging can also be performed between two adjacent sound-emitting units 110 (for example, a damping / dust-proof mesh 140 is set between two adjacent sound-emitting units 110, not shown in the figure), so as to adjust the output sound pressure level of the speaker 100 and the Q value of the output frequency response.

[0097] FIG5 is a top view of the loudspeaker shown in FIG4B . As shown in FIG5 , the two opposite sides of the driving structure 112 are connected to the fixing ring 123 via elastic structures 113, and the elastic structures 113 on both sides are symmetrical with respect to the long axis of the driving structure 112 (see the x-axis shown in FIG5 ). The symmetrically arranged elastic structures 113 can prevent the sound-emitting unit 110 from experiencing an overturned vibration mode. In some embodiments, the elastic structures 113 on both sides are symmetrical with respect to the short axis of the driving structure 112 (see the y-axis shown in FIG5 ). The long axis is the center line of the driving structure 112 along the long axis direction, and the short axis is the center line of the driving structure 112 along the short axis direction.

[0098] In some embodiments, the elastic structure 113 is a bent shape, which can increase the effective length of the elastic structure 113 within the effective space, reduce the stiffness of the elastic structure 113, and thus reduce the impact on the overall stiffness of the diaphragm 111, which is beneficial to increase the vibration amplitude of the diaphragm 111 and improve the acoustic output of the speaker 100.

[0099] Figure 6 is a schematic diagram of the structure of a sound unit 110 according to some embodiments of this specification. The sound unit 110 shown in Figure 6 is similar to the sound unit 110 shown in Figure 4A , with the main difference being that: a lead 114 (i.e., an electrode) is provided on the diaphragm 111, the sound unit 110 does not include an elastic structure 113, and opposite sides of the driving structure 112 are connected to the diaphragm 111 via lead 114. In some embodiments, the lead 114 is directly formed on the diaphragm 111.

[0100] In this embodiment, the driving structure 112 is not connected to the fixing ring 123 , which can prevent the connection between the driving structure 112 and the fixing ring 123 from increasing the rigidity of the diaphragm 111 , thereby avoiding reducing the vibration amplitude of the diaphragm 111 .

[0101] 7 to 9 , the sound unit 110 will be described when the driving structure 112 is an electromagnetic driving structure 112. The sound unit 110 may be the sound unit 110 included in the speaker 100 in any embodiment of this specification.

[0102] FIG7 is a schematic structural diagram of a sound-emitting unit according to other embodiments of this specification.

[0103] As shown in Figure 7, the sound unit 110 includes a diaphragm 111 and a driving structure 112. The peripheral side of the diaphragm 111 is connected to the inner wall of the fixed ring 123, see Figure 4A and related descriptions for details. The driving structure 112 includes a planar coil 1121 and a magnetic circuit assembly. The planar coil 1121 is arranged on the diaphragm 111, and the magnetic circuit assembly includes a magnet 1122, a magnetic conductive plate 1123 and a magnetic conductive ring 1124. Among them, the magnetic conductive ring 1124 is arranged around the planar coil 1121 in a plane perpendicular to the first direction, the magnet 1122 is arranged on the side of the diaphragm 111 away from the planar coil 1121, the magnet 1122 is spaced apart from the diaphragm 111 in the first direction, and the magnetic conductive plate 1123 is supported and connected to the lower surface of the magnet 1122 along the first direction. When an audio signal acts on the planar coil 1121 , the planar coil 1121 generates electromagnetic waves, which cut through the electromagnetic field of the magnetic circuit component, thereby generating a driving force, which drives the diaphragm 111 to vibrate.

[0104] In some embodiments, the outer wall of the magnetic conductive ring 1124 extending in the first direction is connected and fixed to the inner wall of the fixed ring 123. In some embodiments, the circumferential side of the magnetic conductive plate 1123 is connected and fixed to the inner wall of the fixed ring 123. The "connection" described in this specification can be understood as the connection between different parts of the same structure, or after preparing different components or structures separately, the independent components or structures are fixedly connected by welding, riveting, clamping, bolting, adhesive bonding, etc., or during the preparation process, the first component or structure is deposited on the second component or structure by physical deposition (e.g., physical vapor deposition) or chemical deposition (e.g., chemical vapor deposition). The diaphragm 111 divides the cavity inside the fixed ring 123. The diaphragm 111 forms a front cavity (i.e., a first acoustic cavity 1221) upward along the first direction, and a rear cavity (i.e., a second acoustic cavity 1222) is formed between the diaphragm 111 and the magnetic conductive plate 1123. When the diaphragm 111 vibrates, it pushes the air in the front and rear cavities to fluctuate, generating sound waves. In some embodiments, the magnetic plate 1123 is provided with a sound outlet 121 for transmitting sound waves generated in the rear cavity outward. In some embodiments, the driving structure 112 may not include the magnetic plate 1123. Instead, a ring of magnetic conductive material is provided around the magnet 1122 to form a magnetic conductive ring. The magnet 1122 is connected to the inner wall of the fixing ring 123 via the magnetic conductive ring, which can reduce the thickness of the sound unit 110, thereby reducing the thickness of the speaker 100.

[0105] In some embodiments, to maximize the interaction between the magnet 1122 and the planar coil 1121 and thereby generate a greater driving force to drive the diaphragm 111, the magnet 1122 is disposed parallel or approximately parallel to the planar coil 1121. In other words, the diaphragm 111, the magnet 1122, and the planar coil 1121 are disposed parallel or approximately parallel to each other. In some embodiments, to maximize the uniformity of the drive of the diaphragm 111 by the magnet 1122 and the planar coil 1121, thereby enabling the diaphragm 111 to propel air with a greater vibration amplitude, the planar coil 1121 is disposed in the central region of the diaphragm 111, and the magnet 1122 is disposed proximate to the central region of the diaphragm 111 in a plane perpendicular to the first direction.

[0106] In some embodiments, the material of the planar coil 1121 may include copper, gold, aluminum, titanium, platinum, or a composite material thereof. In some embodiments, the magnet 1122 may include a permanent magnet (e.g., aluminum iron boron) and / or an electromagnet. In some embodiments, the material of the magnetic ring 1124 or the magnetic plate 1123 may be a magnetically conductive material. Exemplary magnetically conductive materials may include, but are not limited to, silicon steel, manganese zinc ferrite, nickel zinc ferrite, iron, etc. In some embodiments, the material of the fixing ring 123 may be a semiconductor material.

[0107] In some embodiments, the sound unit 110 can be prepared using a semiconductor process. For example, by preparing a diaphragm layer corresponding to the diaphragm 111 on a silicon wafer, and then depositing, sputtering or evaporating on the diaphragm layer to form a planar coil 1121 layer, and then photolithography is performed to form the desired shape of the planar coil 1121. At this time, the planar coil 1121 is located on the upper surface of the diaphragm 111. For another example, a planar coil 1121 layer is formed on a silicon wafer by deposition, sputtering or evaporation, and photolithography is performed. On this basis, spin coating, sputtering, and evaporation are performed to prepare the planar coil 1121 layer, and photolithography is performed to form the desired shape of the diaphragm layer. At this time, the planar coil 1121 is located on the lower surface of the diaphragm 111. For another example, the fixing ring 123 is made of silicon material and is obtained by back cavity etching of a silicon wafer. In some embodiments, the sound unit 110 can be prepared using a conventional process. For example, the diaphragm 111 can directly use a film of materials such as polyimide (PI) and polyetheretherketone (PEek), or can use polyimide (PI), polyetheretherketone (PEek) and other materials to spin-coat and solidify to form a film; and the planar coil 1121 can be prepared on the diaphragm 111 through a printing process.

[0108] This embodiment adopts the planar coil 1121 and other related structural designs, so that the thickness of the speaker 100 can be reduced.

[0109] FIG8 is a schematic structural diagram of a sound unit 110 according to some other embodiments of the present specification. The sound unit 110 shown in FIG8 is similar to the sound unit 110 shown in FIG7 , with the main difference being that a first magnet 11221 and a second magnet 11222 are respectively provided on opposite sides of the diaphragm 111 in the first direction. A front cavity (i.e., a first acoustic cavity 1221) is formed between the diaphragm 111 and the first magnet 11221, and a rear cavity (i.e., a second acoustic cavity 1222) is formed between the diaphragm 111 and the second magnet 11222. When an audio signal acts on the planar coil 1121, the planar coil 1121 generates electromagnetic waves, and the electromagnetic fields of the first magnet 11221 and the second magnet 11222 are cut, thereby generating a driving force, which drives the diaphragm 111 to vibrate. When the diaphragm 111 vibrates, it pushes the air in the front cavity and the rear cavity to fluctuate, thereby generating sound waves.

[0110] In some embodiments, a circle of magnetically conductive material is provided around each of the first magnet 11221 and the second magnet 11222, forming a magnetic conductive ring. The first magnet 11221 and the second magnet 11222 are connected and fixed to the inner wall of the fixing ring 123 via the magnetic conductive ring. This can reduce the thickness of the sound unit 110, thereby reducing the thickness of the speaker 100. In some embodiments, each of the first magnet 11221 and the second magnet 11222 is provided with a sound outlet 121 for transmitting sound waves generated in the front and rear cavities to the outside.

[0111] In this embodiment, magnets 1122 are provided on opposite sides of the diaphragm 111 in the first direction, so as to increase the magnetic field strength in the area where the planar coil 1121 is located, thereby increasing the driving force applied to the diaphragm 111 and improving the vibration amplitude of the diaphragm 111.

[0112] FIG9 is a schematic structural diagram of a sound unit 110 according to some other embodiments of the present specification. The sound unit 110 shown in FIG9 is similar to the sound unit 110 shown in FIG8 , with the main difference being that a first magnet 11221 and a second magnet 11222 are provided on opposite sides of the diaphragm 111 in the first direction, wherein the first magnet 11221 and the second magnet 11222 are both separate magnets. The separate magnet is a magnet 1122 distributed in a certain shape, and the separate magnet has a hollow area and a magnet area. In some embodiments, the planar coil 1121 is distributed in a ring shape, and the distribution shape of the separate magnet corresponds to the distribution shape of the planar coil 1121. The projection of the magnet area of ​​the separate magnet 1122 along the first direction at least partially overlaps with the projection of the planar coil 1121 along the first direction. In this embodiment, separate magnets are provided, with magnetic regions corresponding to each ring of the planar coil 1121. Each magnetic region corresponding to each ring of the planar coil 1121 can be individually magnetized as needed, enabling individual control of the magnetic pole direction and magnetic field strength at each ring of the planar coil 1121. For example, the magnetic field strength at the middle ring of the planar coil 1121 can be maximized through control, thereby increasing the vibration amplitude of the diaphragm 111.

[0113] In some embodiments, referring to FIG4A , the drive structure 112 may include a piezoelectric drive structure (e.g., the piezoelectric drive structure 1125 shown in FIG10 ), which includes a piezoelectric material. In some embodiments, the Young's modulus of the piezoelectric material is 30 GPa to 100 GPa to ensure that the rigidity of the drive structure 112 does not excessively restrict the vibration of the diaphragm 111. Preferably, the Young's modulus of the piezoelectric material is 40 GPa to 90 GPa. More preferably, the Young's modulus of the piezoelectric material is 50 GPa to 80 GPa.

[0114] FIG. 10 is a cross-sectional view of a piezoelectric driving structure according to some embodiments of the present disclosure.

[0115] As shown in FIG10 , the piezoelectric driving structure 1125 includes, from top to bottom along a first direction, a first electrode layer 11251, a first piezoelectric layer 11252, a second electrode layer 11253, a second piezoelectric layer 11254, and a third electrode layer 11255. In some embodiments, the first electrode layer 11251, the first piezoelectric layer 11252, the second electrode layer 11253, the second piezoelectric layer 11254, and the third electrode layer 11255 are sequentially connected to the diaphragm 111 via adjacent side surfaces.

[0116] In some embodiments, the material of the piezoelectric layer (the first piezoelectric layer 11252 and the second piezoelectric layer 11254) may include, but is not limited to, lead zirconate titanate (PZT) or zinc oxide (ZnO) or aluminum nitride (AlN) and combinations thereof. In some embodiments, the material of the electrode layer (the first electrode layer 11251, the second electrode layer 11253 and the third electrode layer 11255) may include, but is not limited to, platinum (Pt), gold (Au) or titanium (Ti) and any combination thereof. In some embodiments, the material of the diaphragm 111 may be a flexible polymer material. Exemplary flexible polymer materials include, but are not limited to, one or more of polyimide (PI), polyethylene terephthalate (PET), polyethyleneimine (PEI), polyetheretherketone (PEEK), silicone, polycarbonate (PC), vinyl polymer (PVC), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene (PE), polyparaxylene (PPX), etc., and may also be a multilayer composite material composed of the above materials. In some embodiments, the Young's modulus of the flexible polymer material is in the range of 1 GPa-9 GPa (e.g., 2 GPa-8 GPa, 3 GPa-7 GPa, or 4 GPa-6 GPa, etc.). In some embodiments, the material of the diaphragm 111 may be a semiconductor material. Exemplary semiconductor materials include, but are not limited to, silicon (Si), silicon dioxide (SiO2), silicon nitride (Si x N y ), or a multilayer composite material composed of the above materials. In some embodiments, the Young's modulus of the semiconductor material ranges from 100 GPa to 200 GPa (e.g., 120 GPa to 190 GPa, 130 GPa to 180 GPa, or 140 GPa to 170 GPa, etc.).

[0117] In some embodiments, the thickness of the electrode layer may range from 80 nm to 200 nm (e.g., 100 nm to 180 nm, 120 nm to 160 nm, or 130 nm to 150 nm, etc.). In some embodiments, when the piezoelectric layer is prepared using a magnetron sputtering process or a sol-gel or other MEMS process, the thickness of the piezoelectric layer may range from 1 μm to 3 μm (e.g., 1.5 nm to 2.5 nm, 1.6 nm to 2.8 nm, or 1.8 nm to 2.6 nm, etc.). When the piezoelectric layer is prepared using a sintering process, the thickness of the piezoelectric layer may range from 20 μm to 100 μm (e.g., 20 nm to 80 nm, 30 nm to 60 nm, or 30 nm to 50 nm, etc.).

[0118] In some embodiments, the piezoelectric drive structure 1125 has a d33 mode and a d31 mode. In some embodiments, a voltage is applied to each electrode layer along the first direction, and the piezoelectric layer will produce expansion and contraction deformation along the first direction and along the second direction (see the x direction shown in Figure 11A) (as shown in Figure 11B). If only relying on the d33 mode in the first direction, the deformation of the piezoelectric drive structure 1125 is extremely small, and the sound pressure level output by the sound unit 110 cannot meet actual needs. In order to ensure that the piezoelectric drive structure 1125 can have a larger displacement in the first direction so that the amplitude of the diaphragm 111 is larger, the d31 mode in a direction perpendicular to the first direction can be used.

[0119] Figure 11A is a schematic diagram of the structure of a piezoelectric drive structure before deformation according to some embodiments of the present invention. Figure 11B is a schematic diagram of the structure of a piezoelectric drive structure after deformation according to some embodiments of the present invention.

[0120] In some embodiments, the piezoelectric drive structure 1125 includes a sintered piezoelectric ceramic. This sintered piezoelectric ceramic is a piezoelectric ceramic layer (i.e., a piezoelectric layer) produced using a sintering process. The thickness of the piezoelectric ceramic layer is limited by the process and is typically greater than 15 μm. Therefore, the thickness of the piezoelectric ceramic layer is preferably greater than the thickness of the diaphragm 111 (as shown in FIG. 11A ). In this case, the neutral layer 11256 is located within the piezoelectric drive structure 1125 (as shown in FIG. 11B ).

[0121] In some embodiments, when the neutral layer 11256 is located inside the piezoelectric driving structure 1125, in order to ensure that the piezoelectric driving structure 1125 can have a larger displacement in the first direction so that the amplitude of the diaphragm 111 is larger, it can be achieved by designing the polarization direction of each piezoelectric layer and the positive and negative applied voltage, so that the deformation directions of the materials on both sides of the neutral layer 11256 along the first direction are opposite.

[0122] FIG12A is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric driving structure according to some embodiments of this specification.

[0123] Taking two piezoelectric layers as an example, when the polarization directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 are the same (for example, both pointing upward in the first direction as shown in FIG12A ), to achieve opposite deformations of the first piezoelectric layer 11252 and the second piezoelectric layer 11254, i.e., one undergoes tensile deformation and the other undergoes compressive deformation, the electric potential directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 can be opposite. In some embodiments, the first voltage of the first electrode layer 11251 and the third voltage of the third electrode layer 11255 can both be greater than the second voltage of the second electrode layer 11253, or the first voltage of the first electrode layer 11251 and the third voltage of the third electrode layer 11255 can both be less than the second voltage of the second electrode layer 11253. For example, the first voltage is equal to the third voltage, and the second voltage is 0V.

[0124] When both the first and third voltages are greater than the second voltage, the electric potential of the first piezoelectric layer 11252 is directed downward in the first direction, opposite to the polarization direction, causing compression. The electric potential of the second piezoelectric layer 11254 is directed upward in the first direction, aligning with the polarization direction, causing tension. Because the neutral layer 11256 is located within the piezoelectric drive structure 1125, the entire piezoelectric drive structure 1125 bends and deforms downward. At this point, the entire sound unit 110 bends and deforms downward, causing tension in the diaphragm 111. When both the first and third voltages are less than the second voltage, the electric potential of the first piezoelectric layer 11252 is directed upward in the first direction, aligning with the polarization direction, causing tension. The electric potential of the second piezoelectric layer 11254 is directed downward in the first direction, opposite to the polarization direction, causing compression. Since the neutral layer 11256 is located in the piezoelectric driving structure 1125, the piezoelectric driving structure 1125 is bent and deformed upward as a whole. At this time, the sound unit 110 is bent and deformed upward as a whole, and the diaphragm 111 is compressed.

[0125] FIG12B is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric driving structure according to some embodiments of this specification.

[0126] Taking two piezoelectric layers as an example, when the polarization directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 are opposite (for example, as shown in Figure 12B, the polarization direction of the first piezoelectric layer 11252 is upward along the first direction, and the polarization direction of the second piezoelectric layer 11254 is downward along the first direction), in order to make the deformation of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 opposite, the electric potential directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 can be the same. In some embodiments, the first voltage, the second voltage, and the third voltage can decrease or increase in sequence.

[0127] As the first, second, and third voltages decrease in sequence, the electric potential of the first piezoelectric layer 11252 moves downward in the first direction, opposite to the polarization direction, causing compression. The electric potential of the second piezoelectric layer 11254 moves downward in the first direction, opposite to the polarization direction, causing tension. Because the neutral layer 11256 is located within the piezoelectric drive structure 1125, the piezoelectric drive structure 1125 as a whole bends and deforms downward. At this point, the entire sound unit 110 bends and deforms downward, causing the diaphragm 111 to stretch. As the first, second, and third voltages increase in sequence, the electric potential of the first piezoelectric layer 11252 moves upward in the first direction, opposite to the polarization direction, causing tension. The electric potential of the second piezoelectric layer 11254 moves upward in the first direction, opposite to the polarization direction, causing compression. Since the neutral layer 11256 is located in the piezoelectric driving structure 1125, the piezoelectric driving structure 1125 is bent and deformed upward as a whole. At this time, the sound unit 110 is bent and deformed upward as a whole, and the diaphragm 111 is compressed.

[0128] Figure 13A is a schematic diagram of the structure of a piezoelectric drive structure before deformation according to some embodiments of the present invention. Figure 13B is a schematic diagram of the structure of a piezoelectric drive structure after deformation according to some embodiments of the present invention.

[0129] In some embodiments, the piezoelectric drive structure 1125 includes a MEMS piezoelectric ceramic. The MEMS piezoelectric ceramic is a piezoelectric ceramic layer (i.e., a piezoelectric layer) produced using a MEMS process. The piezoelectric ceramic layer is relatively thin, and therefore preferably thinner than the diaphragm 111. As shown in FIG13A , the neutral layer 11256 is located outside the piezoelectric drive structure 1125, i.e., inside the diaphragm 111.

[0130] In some embodiments, when the neutral layer 11256 is located outside the piezoelectric drive structure 1125 and inside the diaphragm 111, in order to ensure that the piezoelectric drive structure 1125 can have a larger displacement in the first direction so that the amplitude of the diaphragm 111 is larger, it can be achieved by designing the polarization direction of each piezoelectric layer and the positive and negative of the applied voltage, so that the deformation directions of the materials of the piezoelectric drive structure 1125 located on one side of the neutral layer 11256 along the first direction are the same, and the deformation directions of the materials located on both sides of the neutral layer 11256 along the first direction are opposite.

[0131] Figure 14A is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric driving structure according to some embodiments of this specification. Figure 14B is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric driving structure according to some embodiments of this specification.

[0132] Taking two piezoelectric layers as an example, when the polarization directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 are opposite, as shown in FIG14A , the polarization direction of the first piezoelectric layer 11252 is upward along the first direction, and the polarization direction of the second piezoelectric layer 11254 is downward along the first direction; alternatively, as shown in FIG14B , the polarization direction of the first piezoelectric layer 11252 is downward along the first direction, and the polarization direction of the second piezoelectric layer 11254 is upward along the second direction. To ensure that the deformation of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 is the same, the electric potential directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 are opposite. In some embodiments, the first voltage of the first electrode layer 11251 and the third voltage of the third electrode layer 11255 may both be greater than the second voltage of the second electrode layer 11253, and the first voltage of the first electrode layer 11251 and the third voltage of the third electrode layer 11255 may both be less than the second voltage of the second electrode layer 11253.

[0133] In Figure 14A, when both the first and third voltages are greater than the second voltage, the electric potential of the first piezoelectric layer 11252 is directed downward along the first direction, opposite to the polarization direction, compressing the first piezoelectric layer 11252. The electric potential of the second piezoelectric layer 11254 is directed upward along the first direction, opposite to the polarization direction, compressing the second piezoelectric layer 11254. Because the neutral layer 11256 is located outside the piezoelectric drive structure 1125 and inside the diaphragm 111, the piezoelectric drive structure 1125 is compressed as a whole, the diaphragm 111 is stretched, and the entire sound unit 110 is bent downward. When both the first and third voltages are less than the second voltage, the electric potential of the first piezoelectric layer 11252 is directed upward along the first direction, identical to the polarization direction, compressing the first piezoelectric layer 11252. The electric potential of the second piezoelectric layer 11254 is directed downward along the first direction, identical to the polarization direction, compressing the second piezoelectric layer 11254. Since the neutral layer 11256 is located outside the piezoelectric driving structure 1125 and inside the diaphragm 111, the piezoelectric driving structure 1125 is stretched as a whole, the diaphragm 111 is compressed, and the sound unit 110 is bent and deformed upward as a whole.

[0134] In Figure 14B, when both the first and third voltages are greater than the second voltage, the electric potential of the first piezoelectric layer 11252 is directed downward along the first direction, the same as the polarization direction, causing the first piezoelectric layer 11252 to stretch. The electric potential of the second piezoelectric layer 11254 is directed upward along the first direction, the same as the polarization direction, causing the second piezoelectric layer 11254 to stretch. Because the neutral layer 11256 is located outside the piezoelectric drive structure 1125 and inside the diaphragm 111, the piezoelectric drive structure 1125 is stretched as a whole, the diaphragm 111 is compressed, and the sound unit 110 is bent upward as a whole. When both the first and third voltages are less than the second voltage, the electric potential of the first piezoelectric layer 11252 is directed upward along the first direction, opposite to the polarization direction, causing the first piezoelectric layer 11252 to compress. The electric potential of the second piezoelectric layer 11254 is directed downward along the first direction, opposite to the polarization direction, causing the second piezoelectric layer 11254 to compress. Since the neutral layer 11256 is located outside the piezoelectric driving structure 1125 and inside the diaphragm 111, the piezoelectric driving structure 1125 is compressed as a whole, the diaphragm 111 is stretched, and the sound unit 110 is bent and deformed downward as a whole.

[0135] Figure 14C is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric drive structure according to some embodiments of this specification. Figure 14D is a schematic diagram of the polarization directions of each piezoelectric layer of a piezoelectric drive structure according to some embodiments of this specification.

[0136] Taking two piezoelectric layers as an example, when the polarization directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 are the same, as shown in FIG14C , the polarization directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 are both upward along the first direction; alternatively, as shown in FIG14D , the polarization directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 are both downward along the first direction. To ensure that the deformation of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 is the same, the electric potential directions of the first piezoelectric layer 11252 and the second piezoelectric layer 11254 are the same. In some embodiments, the first voltage, the second voltage, and the third voltage can decrease or increase in sequence.

[0137] In Figure 14C, when the first, second, and third voltages decrease sequentially, the electric potential of the first piezoelectric layer 11252 is directed downward in the first direction, opposite to the polarization direction, compressing the first piezoelectric layer 11252. The electric potential of the second piezoelectric layer 11254 is directed downward in the first direction, opposite to the polarization direction, compressing the second piezoelectric layer 11254. Because the neutral layer 11256 is located outside the piezoelectric drive structure 1125 and inside the diaphragm 111, the piezoelectric drive structure 1125 is compressed as a whole, the diaphragm 111 is stretched, and the sound unit 110 is bent downward as a whole. When the first, second, and third voltages increase sequentially, the electric potential of the first piezoelectric layer 11252 is directed upward in the first direction, the same as the polarization direction, compressing the first piezoelectric layer 11252. The electric potential of the second piezoelectric layer 11254 is directed upward in the first direction, the same as the polarization direction, compressing the second piezoelectric layer 11254. Since the neutral layer 11256 is located outside the piezoelectric driving structure 1125 and inside the diaphragm 111, the piezoelectric driving structure 1125 is stretched as a whole, the diaphragm 111 is compressed, and the sound unit 110 is bent and deformed upward as a whole.

[0138] In Figure 14D, when the first, second, and third voltages decrease sequentially, the electric potential direction of the first piezoelectric layer 11252 is downward in the first direction, the same as the polarization direction, causing the first piezoelectric layer 11252 to stretch. The electric potential direction of the second piezoelectric layer 11254 is downward in the first direction, the same as the polarization direction, causing the second piezoelectric layer 11254 to stretch. Because the neutral layer 11256 is located outside the piezoelectric drive structure 1125 and inside the diaphragm 111, the piezoelectric drive structure 1125 is stretched as a whole, the diaphragm 111 is compressed, and the sound unit 110 is bent upward as a whole. When the first, second, and third voltages increase sequentially, the electric potential direction of the first piezoelectric layer 11252 is upward in the first direction, opposite to the polarization direction, causing the first piezoelectric layer 11252 to compress. The electric potential direction of the second piezoelectric layer 11254 is upward in the first direction, opposite to the polarization direction, causing the second piezoelectric layer 11254 to compress. Since the neutral layer 11256 is located outside the piezoelectric driving structure 1125 and inside the diaphragm 111, the piezoelectric driving structure 1125 is compressed as a whole, the diaphragm 111 is stretched, and the sound unit 110 is bent and deformed downward as a whole.

[0139] In some embodiments, to comply with the battery power supply and power consumption requirements of common consumer electronic products such as headphones and audio glasses, the absolute values ​​of the first driving voltage and the second driving voltage are both no greater than 5 V. The first driving voltage of the first piezoelectric layer 11252 is the difference between the first voltage and the second voltage, and the second driving voltage of the second piezoelectric layer 11254 is the difference between the second voltage and the third voltage.

[0140] The suspended area on the diaphragm 111 refers to the area where the diaphragm 111 is suspended in the acoustic cavity 122. The suspended area is the surface area of ​​the diaphragm 111 minus the area where the diaphragm 111 is in contact with the fixing ring 123. In some embodiments, the suspended area includes a piezoelectric covering area and a non-piezoelectric covering area. The piezoelectric covering area refers to the surface area of ​​the diaphragm 111 projected on the diaphragm 111 by the piezoelectric driving structure 1125 along the first direction. The non-piezoelectric covering area is the surface area of ​​the diaphragm 111 outside the piezoelectric covering area. The surface area of ​​the diaphragm 111 is the surface area of ​​the diaphragm 111 perpendicular to the first direction.

[0141] In some embodiments, since the thickness of the diaphragm 111 of the sintered piezoelectric ceramic is smaller than the thickness of the piezoelectric layer, the diaphragm 111 has little effect on the resonant frequency and output sound pressure level of the speaker 100 , and the output sound pressure level of the speaker 100 is mainly affected by the size of the piezoelectric driving structure 1125 .

[0142] The parameter β is defined as the ratio of the piezoelectric cover area Sq to the suspended area Sp of the diaphragm 111 , where the piezoelectric cover area is the area of ​​the piezoelectric cover area of ​​the diaphragm 111 and the suspended area Sp is the area of ​​the suspended area of ​​the diaphragm 111 .

[0143] When β is larger, the piezoelectric coverage area is larger, and more piezoelectric materials participate in the drive, thereby pushing the air volume to increase and the output sound pressure level to increase. When β is smaller, the corresponding output sound pressure level decreases.

[0144] FIG. 15 is a frequency response curve diagram of a loudspeaker corresponding to different values ​​of β according to some embodiments of this specification.

[0145] As shown in Figure 15, when β = 0.2, the output sound pressure level of the speaker 100 is low. When β = 0.4, the output sound pressure level is significantly improved compared to β = 0.2. As β continues to increase, for example, when α = 0.5, 0.61, or 0.8, the output sound pressure level of the speaker 100 is further improved. Therefore, in some embodiments, the value range of β is β ≥ 0.4. Preferably, the value range of β is β ≥ 0.61.

[0146] FIG16 is a schematic diagram of a quarter structure of a piezoelectric driving structure according to some embodiments of this specification.

[0147] As shown in Figure 16, the piezoelectric drive structure 1125 can be a multi-piece, separate structure. The first piece of the piezoelectric drive structure 1125 is located in the center area of ​​the diaphragm 111, and the second piece of the piezoelectric drive structure 1125 is arranged around the first piece. Accordingly, the piezoelectric covering area 1125a on the diaphragm 111 can be divided into two parts: a second piezoelectric covering area located in the center area of ​​the diaphragm 111 and a second piezoelectric covering area surrounding the first piezoelectric covering area. The second piezoelectric covering area is annular. The remaining area on the surface of the diaphragm 111, excluding the piezoelectric covering area 1125a, is the non-piezoelectric covering area 1125b.

[0148] In some embodiments, because the thickness of the diaphragm 111 of the piezoelectric ceramic fabricated using the MEMS process is greater than that of the piezoelectric layer, the diaphragm 111 significantly affects the resonant frequency and output sound pressure level of the speaker 100. The compliance of the diaphragm 111 primarily originates from the non-piezoelectric covering region 1125b. When the area of ​​the non-piezoelectric covering region 1125b is small, the compliance of the non-piezoelectric covering region 1125b is too low, resulting in a higher resonant frequency of the speaker 100. When the area of ​​the non-piezoelectric covering region 1125b is large, the compliance of the non-piezoelectric covering region 1125b is too high, resulting in localized high-order modes in the lower frequency range, which affects the output of the speaker 100.

[0149] The parameter α is defined as the ratio of the area Sd of the non-piezoelectric covering region to the suspended area Sp of the diaphragm 111. The area of ​​the non-piezoelectric covering region shown in FIG16 is the sum of the areas of the first piezoelectric covering region and the second piezoelectric covering region.

[0150] When α is large, the non-piezoelectric coverage area is large, and the compliance of the non-piezoelectric coverage area is too great, resulting in local high-order modes at lower frequencies, causing a decrease in the output of the speaker 100. When α is small, the non-piezoelectric coverage area is small, the compliance of the non-piezoelectric coverage area is reduced, the resonant frequency increases, and the output sound pressure level in the frequency band after the resonant frequency also increases.

[0151] FIG. 17 is a frequency response curve diagram of a loudspeaker corresponding to different values ​​of α according to some embodiments of this specification.

[0152] As shown in Figure 17, when α = 0.75, the resonant frequency of the speaker 100 is low, the output sound pressure level is low, and the frequency response has obvious peaks and valleys. When α = 0.65, the output sound pressure level is significantly improved compared to α = 0.75, by more than 10dB. When α continues to decrease, for example, when α = 0.36, 0.24, or 0.15, the resonant frequency of the speaker 100 increases, and the output sound pressure level in the frequency range after the resonant frequency is further improved. Therefore, in some embodiments, the value range of α is α ≤ 0.65. Preferably, the value range of α is α ≤ 0.36.

[0153] In some embodiments, in order to adjust the resonant frequency and vibration mode of the speaker 100 , the speaker 100 may further include a mass block 130 , which is used to adjust the mass and stiffness of the diaphragm 111 , thereby improving the output sound pressure level of the speaker 100 .

[0154] The diaphragm 111 or the driving structure 112 has a long axis direction and a short axis direction, wherein the long axis direction refers to the direction extending along the long axis (see the x-axis shown in FIG5 ), and the short axis direction refers to the direction extending along the short axis (see the y-axis shown in FIG5 ).

[0155] In some embodiments, the mass block 130 can be arranged along the long axis direction, and the size of the mass block 130 in the long axis direction is equal to or smaller than the size of the piezoelectric drive structure 1125. In some embodiments, the ratio of the size of the mass block 130 in the long axis direction (referred to as the long axis dimension) to the long axis dimension of the piezoelectric drive structure 1125 is less than or equal to 1. In some embodiments, the mass block 130 can be arranged along the short axis direction, and the size of the mass block 130 in the short axis direction is equal to or smaller than the size of the piezoelectric drive structure 1125. In some embodiments, the ratio of the size of the mass block 130 in the short axis direction (referred to as the short axis dimension) to the short axis dimension of the piezoelectric drive structure 1125 is less than or equal to 1.

[0156] FIG18 is a schematic diagram of the arrangement of the mass block shown in some embodiments of the specification.

[0157] As shown in FIG18 , the mass block 130 is disposed on the sound unit 110 and is disposed along the long axis. In some embodiments, the mass block 130 is disposed on the piezoelectric drive structure 1125. In some embodiments, the mass block 130 is located at or approximately at the short axis of the piezoelectric drive structure 1125.

[0158] Figure 19A shows a deformation cloud diagram of a diaphragm without a mass block. As shown in Figure 19A , the non-piezoelectrically covered area of ​​diaphragm 111 near housing 120 along its long axis experiences a localized concave deformation in the opposite direction of the deformation of other areas of diaphragm 111. This reduces the overall volume of air displaced by diaphragm 111, thereby reducing the output sound pressure level of speaker 100.

[0159] Figure 19B shows a deformation cloud diagram of the diaphragm with a mass block installed. As shown in Figure 19B, by placing the mass block 130 along the longitudinal axis, the non-piezoelectrically covered area of ​​the diaphragm 111 near the housing 120 along the longitudinal axis can be moved together, keeping the deformation consistent with the rest of the diaphragm 111.

[0160] FIG20 is a schematic diagram of the arrangement of the mass block shown in some embodiments of the specification.

[0161] As shown in Figure 20, the mass block 130 is disposed on the sound unit 110 and is disposed along the short axis. In some embodiments, the mass block 130 is disposed on the piezoelectric drive structure 1125. In some embodiments, the mass block 130 is located at or approximately at the long axis of the piezoelectric drive structure 1125.

[0162] Figure 21A shows a deformation cloud diagram of a diaphragm without a mass block. As shown in Figure 21A , the non-piezoelectrically covered area of ​​diaphragm 111 near housing 120 along its long axis experiences a localized concave deformation in the opposite direction to the deformation of other areas of diaphragm 111. This reduces the overall volume of air displaced by diaphragm 111, thereby reducing the output sound pressure level of speaker 100.

[0163] Figure 21B shows a deformation cloud diagram of the diaphragm with a mass block installed. As shown in Figure 21B, although the placement of mass block 130 along the minor axis does not improve the concavity of the non-piezoelectrically covered area of ​​diaphragm 111 near housing 120 along the major axis, it does increase the maximum displacement of the central portion of speaker unit 110 from an absolute value of 15 μm to 20 μm, and reduces the absolute value of the displacement of the concavity in the non-piezoelectrically covered area in the opposite direction from the central portion from 30 μm to 25 μm. This reduces the amount of sound cancellation caused by the opposite displacement of the central portion and the concavity in the non-piezoelectrically covered area, effectively increasing the overall air displacement and, consequently, the output sound pressure level.

[0164] FIG22 is a schematic diagram of the arrangement of the mass block shown in some embodiments of the specification.

[0165] As shown in FIG20 , a mass block 130 is disposed on the sound unit 110. The mass block 130 has specific dimensions in both the major and minor axes, such that the mass block 130 is disposed along both the major and minor axes. In some embodiments, the mass block 130 is disposed on the piezoelectric drive structure 1125. In some embodiments, the mass block 130 is located at or approximately in the middle region of the piezoelectric drive structure 1125. In some embodiments, the major axis dimension of the mass block 130 is equal to or smaller than the major axis dimension of the piezoelectric drive structure 1125, and the minor axis dimension of the mass block 130 is equal to or smaller than the minor axis dimension of the piezoelectric drive structure 1125.

[0166] Figure 23A shows a deformation cloud diagram of a diaphragm without a mass block. As shown in Figure 23A , the non-piezoelectrically covered area of ​​diaphragm 111 near housing 120 along its long axis experiences a localized concave deformation in the opposite direction to the deformation of other areas of diaphragm 111. This reduces the overall volume of air displaced by diaphragm 111, and thus the output sound pressure level of speaker 100.

[0167] Figure 23B shows a deformation cloud diagram of the diaphragm with a mass block installed. As shown in Figure 23B , by placing mass blocks 130 along the major and minor axes, the non-piezoelectrically covered area of ​​the diaphragm 111 near the housing 120 along the major axis can be moved together, keeping the deformation consistent with the rest of the diaphragm 111. This also increases the maximum displacement of the speaker 100's sound unit 110, effectively increasing the overall amount of air moved and, in turn, the output sound pressure level.

[0168] FIG24A is a schematic structural diagram of a laminated (10-layer) loudspeaker according to some embodiments of the present specification; FIG24B is a frequency response graph of a laminated loudspeaker and a single-layer loudspeaker according to some embodiments of the present specification.

[0169] In some embodiments of this specification, a laminated speaker composed of 10 (layers) of sound units 110 is used as an example to compare with a single-layer speaker under the same conditions (e.g., the same materials, the same structural dimensions, etc.). As shown in FIG24A , the height of the first acoustic cavity 1221 formed between the front housing 1201 and the first adjacent sound unit 1101 in the first direction is represented as hq1, and the height of the first sound outlet 1211 coupled to the first acoustic cavity 1221 in the first direction is represented as hk1; the height of the third acoustic cavity 1223 formed between two adjacent sound units 110 (e.g., the i-1th sound unit 110i-1 and the i-th sound unit 110i) in the first direction is represented as hq i The height of the i-th sound outlet 121i coupled to the third acoustic cavity 1223 in the first direction is represented by hk i The height of the second acoustic cavity 1222 formed between the rear housing 1202 and its adjacent nth sound unit 110n in the first direction is represented by hq n+1 , and the height of the n+1th sound outlet 121(n+1) coupled to the second acoustic cavity 1222 in the first direction is represented by hk n+1 . Wherein, i is an integer greater than 1 and less than n.

[0170] As shown in Figure 24B, SP10 represents the output sound pressure level of a stacked (10-layer) speaker; SP1 represents the output sound pressure level of a single-layer speaker. i =300um, hq1=hq n+1 =150um, hk i =100um、hk1=hk n+1=50um, at the same frequency, the output sound pressure level of the stacked speaker (SP10 shown in FIG24B ) is about 60dB, while the output sound pressure level of the single-layer speaker (SP1 shown in FIG24B ) is about 40dB. It can be seen that the output sound pressure level of the stacked speaker is increased by about 20dB (20dB = 20×log 10 (10)). Further explanation: when hq i =300um, hq1=hq n+1 =150um, hk i =100um、hk1=hk n+1 =50 μm, the output sound pressure level of the laminated loudspeaker is not reduced due to the small height of the acoustic cavity 122 and the sound outlet hole 121 coupled to the acoustic cavity 122.

[0171] It can be understood that when the height of the acoustic cavity 122 and the sound outlet 121 coupled to the acoustic cavity 122 is constant, while ensuring that the structural strength of the speaker 100 is not affected, the larger the width of the sound outlet 121 in the direction perpendicular to the first direction, that is, the larger the area of ​​the sound outlet 121, the smaller its acoustic resistance, and the higher the output sound pressure level. Therefore, the height of the acoustic cavity 122 and the sound outlet 121 coupled to the acoustic cavity 122 in the laminated speaker in the first direction is preferably hq i ≥300um、hq1≥150um、hq n+1 ≥150um, hk i ≥100um、hk1≥50um、hk n+1 ≥50um.

[0172] Figure 25 is an exemplary schematic diagram of an acoustic output device according to some embodiments of the present specification; Figure 26A is an exemplary schematic diagram 1 of an acoustic output device according to other embodiments of the present specification; Figure 26B is an exemplary schematic diagram 2 of an acoustic output device according to some embodiments of the present specification; Figure 27 is an exemplary schematic diagram of an acoustic output device according to still other embodiments of the present specification; Figure 28 is a frequency response curve diagram of an acoustic output device according to some embodiments of the present specification.

[0173] In some embodiments, this specification provides an acoustic output device, including: a low-frequency unit and a high-frequency unit, wherein the low-frequency unit includes the speaker 100 described in Figures 1A-24B and related contents.

[0174] In some embodiments, the acoustic output device 200 may include one or more of a back-hook headset, an ear-hook headset, an in-ear headset, and glasses.

[0175] In some embodiments, the acoustic output device 200 may include at least one low-frequency unit and at least one high-frequency unit. As shown in FIG25 , for open-ear headphones, a low-frequency unit and a high-frequency unit may be provided on each of the two headphones.

[0176] As shown in FIG26B , for open-ear audio glasses, two low-frequency units and one high-frequency unit may be provided on each side of the temples to enhance the output sound pressure level at low frequencies.

[0177] As shown in Figure 28, SP d For low frequency unit, SP q For high frequency unit, SP h The acoustic output device 200 after frequency division and combination, the dotted line represents the frequency division line L (ie SP d With SP q In some embodiments, the intersection of the frequency response curves of the low-frequency unit and the high-frequency unit is within the range of 300 Hz-1000 Hz, that is, the crossover line L is within the range of 300 Hz-1000 Hz.

[0178] The low-frequency unit refers to a structural unit in the acoustic output device 200 that can achieve a good sound pressure level output in the low frequency band. In some embodiments, the low-frequency unit includes but is not limited to an air-conducting piezoelectric stack speaker (such as the speaker 100).

[0179] In some embodiments, the low-frequency unit can operate within a first frequency range with the crossover line L as the upper boundary. That is, the upper boundary of the first frequency range is within the range of 300 Hz-1000 Hz. In some embodiments, the upper boundary of the first frequency range can also be within other suitable ranges. For example, the upper boundary of the first frequency range is within the range of 300 Hz-1500 Hz. In some embodiments, the first frequency range can be referred to as a low-frequency band.

[0180] In some embodiments, since the air-conducting piezoelectric stack speaker (such as the speaker 100 ) can output a larger sound pressure level in the low frequency band, in order to better achieve a fuller low-frequency effect, the air-conducting piezoelectric stack speaker (such as the speaker 100 ) can be used in the low frequency band.

[0181] The high frequency unit refers to a structural unit in the acoustic output device 200 that can achieve a good sound pressure level output in the high frequency band. In some embodiments, the high frequency unit may include an air conduction speaker and / or a bone conduction speaker.

[0182] In some embodiments, the high-frequency unit can operate within at least a second frequency range with the crossover line L as the lower boundary. In some embodiments, the second frequency range can be referred to as the high-frequency band. As shown in Figures 25-28, when the high-frequency unit is a bone conduction speaker, since bone conduction speakers can output a higher sound pressure level in the high-frequency band but are slightly insufficient in the low-frequency band, in order to achieve a full-band sound effect, the acoustic output device 200 can use a method of combining a bone conduction speaker with an air-conducted piezoelectric stack speaker (such as speaker 100), so that the bone conduction speaker is responsible for the high-frequency band, while the air-conducted piezoelectric stack speaker (such as speaker 100) is responsible for the low-frequency band. Of course, in some embodiments, the bone conduction speaker can operate in addition to the high-frequency band and also in the low-frequency band to further enhance the low-frequency effect. In this case, the output of the air-conducted piezoelectric stack speaker (such as speaker 100) dominates in the low-frequency band.

[0183] As shown in Figures 25-27 , the high-frequency unit of acoustic output device 200 can also be an air conduction speaker. In this case, the acoustic output device can adopt a frequency division design or not. That is, the air conduction speaker (high-frequency unit) can operate only in the high frequency band (the second frequency range) or simultaneously in the low and high frequency bands. In this case, the output of the air conduction speaker and the air-conducting piezoelectric stack speaker (e.g., speaker 100) in the low frequency band is superimposed to further enhance the low-frequency effect.

[0184] In some embodiments, the acoustic output device 200 has a height direction parallel to the first direction and a thickness direction perpendicular to the first direction. The low-frequency unit and the high-frequency unit are arranged parallel to each other in the height direction, with the low-frequency unit located below the high-frequency unit; or the low-frequency unit and the high-frequency unit are arranged parallel to each other in the thickness direction, with the high-frequency unit located on the side of the acoustic output device 200 closest to the user.

[0185] The height direction parallel to the first direction can be understood as the direction parallel to the front face of the acoustic output device 200 close to the user; the thickness direction perpendicular to the first direction can be understood as the direction perpendicular to the front face of the acoustic output device 200 close to the user.

[0186] In some embodiments of this specification, by disposing the high-frequency unit on the side of the acoustic output device 200 close to the user, when the high-frequency unit adopts the bone conduction speaker 100, it can be more conducive to the transmission of sound, thereby improving the user experience.

[0187] As shown in Figures 25-27, the high-frequency unit is acoustically coupled to a first hole 201 provided in the acoustic output device 200, and the low-frequency unit is acoustically coupled to a second hole 202 provided in the acoustic output device 200. Both the first hole 201 and the second hole 202 are positioned toward the user to better output sound to the user. The first hole 201 and the second hole 202 may be the same hole or different holes.

[0188] As shown in FIG25 , when the high frequency unit of the acoustic output device 200 adopts a bone conduction speaker 100SP g In this case, there is no need to provide the first hole portion 201 for acoustic coupling with the high frequency unit.

[0189] In some embodiments, if the first hole portion 201 and the second hole portion 202 are the same hole, it can be understood that the first hole portion 201 and the second hole portion 202 are shared sound-emitting holes for the high-frequency unit and the low-frequency unit; if the first hole portion 201 and the second hole portion 202 are different holes, it can be understood that the first hole portion 201 and the second hole portion 202 are independently provided sound-emitting holes. By providing the first hole portion 201 and the second hole portion 202 that are acoustically coupled to the high-frequency unit and the low-frequency unit respectively, the cavity of the high-frequency unit and the low-frequency unit can be isolated, which is conducive to improving the sound transmission effect.

[0190] In some embodiments, the acoustic output device 200 may include multiple sound-emitting holes. For example, the acoustic output device 200 may include a first hole 201 acoustically coupled to the high-frequency unit and two second holes 202 acoustically coupled to the low-frequency unit, or may include two first holes 201 acoustically coupled to the high-frequency unit and one second hole 202 acoustically coupled to the low-frequency unit (as shown in FIG27 ). For another example, the acoustic output device 200 may include both independently arranged first holes 201 and second holes 202 acoustically coupled to the high-frequency unit and the low-frequency unit, respectively, or may include a sound-emitting hole shared by the high-frequency unit and the low-frequency unit, or both low-frequency units, referred to as a third hole 203 (as shown in FIG26A-26B ).

[0191] The beneficial effects that may be brought about by the embodiments of this specification include but are not limited to: 1) Based on the fact that two adjacent sound-emitting units in a plurality of sound-emitting units and sharing at least one acoustic cavity in a plurality of acoustic cavities vibrate in opposite directions in at least part of the low-frequency band, combined with the design of the sound outlet holes shown in some embodiments of this specification, the sound pressure level output by a loudspeaker with n sound-emitting units (stacked loudspeaker) can be increased by 20×log compared to the sound pressure level output by a loudspeaker with only one sound-emitting unit (single-layer loudspeaker). 10(n) times; 2) Since the thickness of the piezoelectric speaker is relatively thin, by arranging multiple piezoelectric sound units at intervals in the first direction (thickness direction), a larger low-frequency output can be obtained while meeting the smaller design size of the speaker; 3) Flexible adjustment of the number of sound units in the first direction can make the speaker suitable for more usage scenarios, making it widely applicable and practical; 4) By setting a mass block along the long axis or short axis direction of the sound unit on the sound unit, the mass and stiffness of the diaphragm can be adjusted, and the deformation of the diaphragm during vibration can be adjusted, thereby improving the output sound pressure level of the speaker; 5) By limiting the voltage applied to the first piezoelectric layer and the second piezoelectric layer, the speaker can be more in line with the battery power supply capacity and power consumption of common consumer electronic products such as headphones and audio glasses, making the speaker more practical.

[0192] While the basic concepts have been described above, it will be apparent to those skilled in the art that the detailed disclosure is merely illustrative and does not limit this specification. Although not explicitly stated herein, various modifications, improvements, and revisions to this specification may be made by those skilled in the art. Such modifications, improvements, and revisions are suggested in this specification and remain within the spirit and scope of the exemplary embodiments of this specification.

[0193] This specification also uses specific terms to describe the embodiments of this specification. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "one embodiment," "an embodiment," or "an alternative embodiment" two or more times in different locations in this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of this specification may be appropriately combined.

[0194] Similarly, it should be noted that, in order to simplify the presentation of this specification and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this specification sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not imply that the subject matter of this specification requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single disclosed embodiment.

[0195] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required characteristics of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0196] Finally, it should be understood that the embodiments in this specification are intended only to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly described and illustrated in this specification.

Claims

1. A speaker, comprising: A plurality of sound-emitting units are arranged at intervals along a first direction, and the plurality of sound-emitting units all vibrate along the first direction; The shell is configured to accommodate and support the multiple sound-emitting units, the shell is provided with multiple sound outlets, the shell and the multiple sound-emitting units form multiple acoustic cavities, each acoustic cavity is acoustically coupled with at least one sound outlet on the shell, wherein: The plurality of sound generating units each include a diaphragm and a driving structure arranged on the diaphragm.

2. The loudspeaker according to claim 1, wherein The driving structure includes a piezoelectric driving structure, and the shell includes a plurality of fixing rings, each fixing ring fixing a diaphragm of a sound-emitting unit.

3. The loudspeaker according to claim 2, wherein: The piezoelectric driving structure is connected to the fixing ring via an elastic structure, and the elastic structure is symmetrical with respect to the major axis or the minor axis of the piezoelectric driving structure.

4. The loudspeaker according to claim 2, wherein: The diaphragm is provided with a lead wire, and the piezoelectric driving structure is connected to the lead wire.

5. The loudspeaker according to claim 1, wherein The driving structure includes a planar coil.

6. The loudspeaker according to claim 5, wherein: The loudspeaker further comprises a magnet disposed in the housing, wherein the magnet is disposed on a side of the diaphragm away from the planar coil.

7. The loudspeaker according to claim 5, wherein: The loudspeaker further comprises a magnet disposed in the housing. In the first direction, the magnets are respectively disposed on both sides of the diaphragm, and the planar coil is located between the two magnets.

8. The loudspeaker according to claim 5, wherein: The speaker further includes a magnet disposed in the housing, wherein the magnet includes a separate magnet, and the separate magnet at least partially overlaps with a projection area of ​​the planar coil in the first direction.

9. The loudspeaker according to claim 1, wherein: The shell includes a plurality of fixing rings, each fixing ring fixes a sound-emitting unit, and two sound outlet holes are provided on the circumference of each fixing ring, and the two sound outlet holes are respectively coupled with the acoustic cavities on opposite sides of the sound-emitting unit.

10. The loudspeaker according to claim 9, wherein The shell includes a front shell and a rear shell, a first acoustic cavity is formed between the front shell and an adjacent sound-emitting unit, a second acoustic cavity is formed between the rear shell and another adjacent sound-emitting unit, and a third acoustic cavity is formed between two adjacent sound-emitting units, and a thickness of the first acoustic cavity and / or the second acoustic cavity along the first direction is less than a thickness of the third acoustic cavity along the first direction.

11. The loudspeaker according to claim 10, wherein: The height of the first acoustic cavity and the second acoustic cavity in the first direction is greater than or equal to 150um, the height of the third acoustic cavity in the first direction is greater than or equal to 300um, the height of the sound holes corresponding to the first acoustic cavity and the second acoustic cavity in the first direction is greater than or equal to 50um, and the height of the sound holes corresponding to the third acoustic cavity in the first direction is greater than or equal to 100um.

12. The loudspeaker according to claim 9, wherein The shell includes a front shell and a rear shell, each of the fixing rings is provided with at least two electrodes, and the at least two electrodes on each of the fixing rings are respectively connected to the front shell or the rear shell through corresponding conducting electrodes.

13. The loudspeaker according to claim 2, wherein: The piezoelectric driving structure includes a piezoelectric material, and the Young's modulus of the piezoelectric material is 30 GPa-100 GPa.

14. The loudspeaker of claim 13, wherein: The piezoelectric driving structure includes sintered piezoelectric ceramics, and the neutral layer of the sound generating unit is located in the piezoelectric driving structure.

15. The loudspeaker of claim 14, wherein: The piezoelectric driving structure comprises a first piezoelectric layer, a second piezoelectric layer, a first electrode layer, a second electrode layer and a third electrode layer, and in the first direction, the first electrode layer, the first piezoelectric layer, the second electrode layer, the second piezoelectric layer and the third electrode layer are arranged in sequence; The first piezoelectric layer and the second piezoelectric layer have the same polarization direction, the first voltage of the first electrode layer and the third voltage The third voltage of the electrode layer is greater than or less than the second voltage of the second electrode layer.

16. The loudspeaker of claim 14, wherein: The piezoelectric driving structure comprises a first piezoelectric layer, a second piezoelectric layer, a first electrode layer, a second electrode layer and a third electrode layer, and in the first direction, the first electrode layer, the first piezoelectric layer, the second electrode layer, the second piezoelectric layer and the third electrode layer are arranged in sequence; The polarization directions of the first piezoelectric layer and the second piezoelectric layer are opposite, and the first voltage of the first electrode layer, the second voltage of the second electrode layer, and the third voltage of the third electrode layer decrease or increase in sequence.

17. The loudspeaker of claim 13, wherein: The piezoelectric driving structure includes MEMS piezoelectric ceramics, and the neutral layer of the sound generating unit is located outside the piezoelectric driving structure.

18. The loudspeaker of claim 17, wherein: The piezoelectric driving structure comprises a first piezoelectric layer, a second piezoelectric layer, a first electrode layer, a second electrode layer and a third electrode layer, and in the first direction, the first electrode layer, the first piezoelectric layer, the second electrode layer, the second piezoelectric layer and the third electrode layer are arranged in sequence; The polarization directions of the first piezoelectric layer and the second piezoelectric layer are opposite, and the first voltage of the first electrode layer and the third voltage of the third electrode layer are both greater than or less than the second voltage of the second electrode layer.

19. The loudspeaker of claim 17, wherein: The piezoelectric driving structure comprises a first piezoelectric layer, a second piezoelectric layer, a first electrode layer, a second electrode layer and a third electrode layer, and in the first direction, the first electrode layer, the first piezoelectric layer, the second electrode layer, the second piezoelectric layer and the third electrode layer are arranged in sequence; The polarization directions of the first piezoelectric layer and the second piezoelectric layer are the same, and the first voltage of the first electrode layer, the second voltage of the second electrode layer, and the third voltage of the third electrode layer decrease or increase in sequence.

20. The loudspeaker according to any one of claims 15, 16, 18, and 19, wherein: The first driving voltage of the first piezoelectric layer is the difference between the first voltage and the second voltage, the second driving voltage of the second piezoelectric layer is the difference between the second voltage and the third voltage, and the absolute value of the first driving voltage and the absolute value of the second driving voltage are both no higher than 5V.

21. The loudspeaker of claim 14, wherein: The diaphragm includes a piezoelectric covering area and a non-piezoelectric covering area, and a ratio of a first area of ​​the piezoelectric covering area to a suspended area of ​​the sound unit is greater than or equal to 0.

4.

22. The loudspeaker of claim 17, wherein: The diaphragm includes a piezoelectric covering area and a non-piezoelectric covering area, and the ratio of the second area of ​​the non-piezoelectric covering area to the suspended area of ​​the sound unit is less than 0.

65.

23. The loudspeaker of claim 1, wherein: The diaphragm or the driving structure has a long axis direction and a short axis direction, and the sound unit also includes a mass block arranged along the long axis direction or the short axis direction. In the long axis direction or the short axis direction, the size of the mass block is smaller than the size of the piezoelectric driving structure.

24. An acoustic output device, comprising: A low frequency unit and a high frequency unit, wherein the low frequency unit comprises a loudspeaker as claimed in any one of claims 1 to 22, wherein: The intersection of the frequency response curves of the low-frequency unit and the high-frequency unit is within the range of 300 Hz-1000 Hz.

25. The acoustic output device of claim 24, wherein: The high frequency unit includes an air conduction speaker and / or a bone conduction speaker.

26. The acoustic output device of claim 24, wherein: The high-frequency unit operates at least within a frequency range with the intersection point as a lower boundary.

27. The acoustic output device of claim 24, wherein: The acoustic output device has a height direction parallel to the first direction and a thickness direction perpendicular to the first direction, wherein: The low-frequency unit and the high-frequency unit are arranged in parallel in the height direction, and the low-frequency unit is located at the lower side of the high-frequency unit; Alternatively, the low-frequency unit and the high-frequency unit are arranged in parallel in the thickness direction, and the high-frequency unit is arranged on a side of the acoustic output device close to the user.

28. The acoustic output device of claim 27, wherein: The high-frequency unit is acoustically coupled to a first hole portion provided in the acoustic output device, and the low-frequency unit is acoustically coupled to a second hole portion provided in the acoustic output device, wherein both the first hole portion and the second hole portion are provided toward the user, wherein: The first hole portion and the second hole portion are the same hole or different holes.

29. The acoustic output device according to any one of claims 24 to 28, wherein: The acoustic output device includes at least one of a back-hook earphone, an ear-hook earphone, an in-ear earphone, and glasses.

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