Piezoelectric loudspeaker

Abstract

The invention relates to the field of loudspeakers, in particular to a piezoelectric loudspeaker which comprises a shell and a piezoelectric module. The piezoelectric module comprises a piezoelectric motor, a first vibrating diaphragm assembly, a second vibrating diaphragm assembly, a first conduction assembly and a second conduction assembly. The first vibrating diaphragm assembly and the second vibrating diaphragm assembly are arranged on the two sides of the piezoelectric motor respectively, and the first conduction assembly is arranged between the piezoelectric motor and the first vibrating diaphragm assembly; the second conduction assembly is arranged between the piezoelectric motor and the second diaphragm assembly; a first cavity is formed between the first vibrating diaphragm assembly and the inner wall of the shell, a second cavity is formed between the first vibrating diaphragm assembly and the second vibrating diaphragm assembly, and a third cavity is formed between the second vibrating diaphragm assembly and the inner wall of the shell; a separation structure is arranged in the second cavity, so that the second cavity is divided into a first cavity part and a second cavity part which are independent from each other; the housing is provided with a sound outlet hole. The loudspeaker has the advantage of high sensitivity.

Description

Technical Field

[0001] The present invention relates to the field of loudspeakers, and in particular to a piezoelectric loudspeaker. Background Art

[0002] A piezoelectric speaker is a speaker that radiates sound by deforming a piezoelectric sheet after power is applied. In traditional processing techniques, a thin piezoelectric sheet is bonded to one or both sides of a sheet made of copper, stainless steel, etc. to form a piezoelectric motor. The surface of the piezoelectric sheet is the positive electrode, and the substrate made of copper or stainless steel is the negative electrode. When a voltage signal is applied to the positive and negative electrodes, the piezoelectric motor generates convex and concave vibrations, causing the air near the piezoelectric motor to be compressed / expanded due to its deformation and cooperate with the diaphragm to radiate sound waves outward.

[0003] The piezoelectric speakers in the prior art are mainly single-diaphragm speakers, that is, a single piezoelectric motor is connected to only one diaphragm, which is limited by its sensitivity, resulting in poor bass effect. Summary of the invention

[0004] An object of the embodiments of the present invention is to provide a piezoelectric speaker to improve its sensitivity.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a piezoelectric speaker, including a shell and a piezoelectric module arranged in the shell; the piezoelectric module includes a piezoelectric motor, a first diaphragm assembly, a second diaphragm assembly, a first conduction assembly and a second conduction assembly; wherein the first diaphragm assembly and the second diaphragm assembly are respectively arranged on both sides of the piezoelectric motor, the first conduction assembly is arranged between the piezoelectric motor and the first diaphragm assembly, and transmits the vibration of the piezoelectric motor to the first diaphragm assembly; the second conduction assembly is arranged between the piezoelectric motor and the second diaphragm assembly, and transmits the vibration of the piezoelectric motor to the on the second diaphragm assembly; and, a first cavity is formed between the first diaphragm assembly and the inner wall of the shell, a second cavity is formed between the first diaphragm assembly and the second diaphragm assembly, and a third cavity is formed between the second diaphragm assembly and the inner wall of the shell; a partition structure is provided in the second cavity to divide the second cavity into a first cavity portion and a second cavity portion which are independent of each other, and the first cavity portion is closer to the first diaphragm assembly, and the second cavity portion is closer to the second diaphragm assembly; a sound outlet hole is provided on the shell, and one end of the sound outlet hole is connected to the outside of the shell, and the other end is connected to the first cavity and the second cavity portion respectively.

[0006] Compared with the prior art, the piezoelectric motor in the embodiment of the present invention transmits vibration to the diaphragm assemblies on both sides thereof through the conduction components on both sides thereof, so that the first diaphragm assembly vibrates and radiates to output high-frequency sounds, and the second diaphragm assembly vibrates and radiates to output low-frequency sounds. The first cavity and the third cavity can assist in regulating the low-frequency part of the frequency response, so that the sound emitted by the speaker, especially the bass effect, is better, thereby improving the sensitivity of the speaker.

[0007] In addition, the first diaphragm assembly includes a first diaphragm and a first middle sticker attached to the first diaphragm, the first diaphragm is a flexible film, the first middle sticker is a rigid sheet, and the first middle sticker is located on the side of the first diaphragm away from the piezoelectric motor; the first transmission assembly includes a first transmission block and a transmission frame, one side of the first transmission block abuts against one side of the piezoelectric motor, the other side abuts against one side of the transmission frame, and the other side of the transmission frame abuts against the first diaphragm. In this way, the first middle sticker provides support for the first diaphragm, and the first transmission block and the transmission frame are used to transmit the vibration of the piezoelectric motor to the first diaphragm.

[0008] In addition, the second diaphragm assembly includes a second diaphragm and a second middle sticker attached to the second diaphragm, the second diaphragm is a flexible film, the second middle sticker is a rigid sheet, and the second middle sticker is located on the side of the second diaphragm away from the piezoelectric motor; the second transmission assembly includes a second transmission block and a transmission rod, one side of the second transmission block abuts against the other side of the piezoelectric motor, and the other side abuts against one end of the transmission rod, the transmission rod passes through the partition structure, and the other end of the transmission rod abuts against the second diaphragm. In this way, the second middle sticker provides support for the second diaphragm, and the second transmission block and the transmission rod are used to transmit the vibration of the piezoelectric motor to the second diaphragm.

[0009] In addition, the shell includes an upper cover, a middle frame and a lower cover, the middle frame is arranged between the upper cover and the lower cover, and the first cavity is formed between the upper cover and the first diaphragm, and the third cavity is formed between the lower cover and the second diaphragm; along the length direction of the shell, the two sides of the piezoelectric motor are respectively fixedly connected to the two sides of the inner wall of the middle frame; along the width direction of the shell, there are gaps between the two sides of the piezoelectric motor and the two sides of the inner wall of the middle frame, so that the second cavity is formed between the first diaphragm and the second diaphragm; and a lead through hole is formed at a position corresponding to the piezoelectric motor on the shell, a conductive column is sealed in the lead through hole, and one end of the conductive column is connected to the piezoelectric motor, and the other end extends to the outside of the shell.

[0010] In addition, the middle frame includes a frame body portion and a plate body portion stacked in sequence along the thickness direction thereof, the frame body portion is arranged above the plate body portion, and the piezoelectric motor is fixedly connected to the frame body portion at both sides along the length direction; the plate body portion is provided with a through hole along the thickness direction thereof; the partition structure is provided as an elastic folding ring, the elastic folding ring is embedded and sealed in the through hole, and the transmission rod is embedded and sealed in the elastic folding ring. Since the transmission rod needs to pass through the partition structure, and the transmission rod needs to move up and down with the vibration motor, the partition structure is provided as an elastic folding ring so that the elastic folding ring can move up and down with the transmission rod, thereby avoiding the partition structure from affecting the up and down movement of the transmission rod.

[0011] In addition, the housing further comprises a rear cover, the rear cover is arranged on a side of the housing away from the sound outlet, and a connecting channel is formed on the inner wall of the rear cover, one end of the connecting channel is connected to the first cavity, and the other end is connected to the third cavity, so that the first cavity and the third cavity are connected via the connecting channel. In this way, the connecting channel arranged on the rear cover connects the first cavity and the third cavity, forming a larger adjustment cavity, so as to better adjust the sound effect emitted by the speaker, especially the bass effect, thereby improving the sensitivity of the speaker.

[0012] In addition, a through hole is provided on one side of the lower cover away from the sound outlet, and one end of the through hole is connected to the third cavity, and the other end is connected to the outside of the shell. In this way, the third cavity is connected to the outside of the shell through the through hole to form a larger adjustment cavity, thereby adjusting to form a better sound effect, especially a bass effect.

[0013] In addition, the vibration motor includes a substrate and two piezoelectric sheets, and the two piezoelectric sheets are respectively arranged on both sides of the substrate along the thickness direction thereof to form a flat motor.

[0014] In addition, two through grooves are formed on the substrate and penetrate the substrate along the thickness direction of the substrate. The through grooves extend along the width direction of the substrate, and along the length direction of the substrate, the two through grooves are spaced apart on the substrate near the two sides of the piezoelectric sheet, so that the substrate is cantilevered to form a cantilever beam piezoelectric motor.

[0015] In addition, four "U"-shaped connecting arms are provided on the substrate, and each of the "U"-shaped connecting arms is respectively arranged on both sides of the substrate along the width direction, and corresponds to the two sides of each of the through grooves along the width direction; and, the open end of the "U"-shaped connecting arm is connected to the side of the substrate along the width direction, and the closed end of the "U"-shaped connecting arm extends into the through groove along the width direction, so that the substrate can be bent along the "U"-shaped connecting arm to form a folded beam piezoelectric motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0017] Figure 1 is a schematic cross-sectional structural diagram of a piezoelectric speaker provided according to an embodiment of the present invention;

[0018] Figure 2 is a schematic cross-sectional structural diagram of a piezoelectric speaker provided according to another embodiment of the present invention;

[0019] Figure 3 is a schematic cross-sectional structural diagram of a piezoelectric speaker provided according to yet another embodiment of the present invention;

[0020] Figure 4 is a structural schematic diagram of a piezoelectric speaker housing provided with a conductive column according to an embodiment of the present invention;

[0021] Figure 5 is a schematic structural diagram of a piezoelectric speaker provided in an embodiment of the present invention, in which a housing is not provided with a conductive column;

[0022] Figure 6 is a structural schematic diagram of a configuration method of sound outlet holes on a shell of a piezoelectric speaker provided in an embodiment of the present invention;

[0023] Figure 7 is a structural schematic diagram of another arrangement method of the sound outlet holes on the shell of the piezoelectric speaker provided in an embodiment of the present invention;

[0024] Figure 8 is an exploded view of a piezoelectric module of a piezoelectric speaker provided in an embodiment of the present invention;

[0025] Fig. 9 is a schematic structural diagram of a transmission frame of a piezoelectric speaker provided according to an embodiment of the present invention;

[0026] Fig.10 is a schematic structural diagram of a middle frame of a piezoelectric speaker provided according to an embodiment of the present invention;

[0027] Fig.11 is a schematic cross-sectional structural diagram of a middle frame of a piezoelectric speaker provided according to an embodiment of the present invention;

[0028] Fig.12 is a schematic structural diagram of an elastic folding ring and a transmission rod of a piezoelectric speaker provided in an embodiment of the present invention;

[0029] Fig.13 yes Fig.12 A front view of

[0030] Fig.14 is a schematic structural diagram of a flat piezoelectric motor of a piezoelectric speaker provided according to an embodiment of the present invention;

[0031] Fig.15 yes Fig.14 A front view of

[0032] Fig.16 is a schematic diagram of the low-frequency vibration amplitude of a flat piezoelectric motor of a piezoelectric speaker provided in an embodiment of the present invention;

[0033] Fig.17 is a schematic structural diagram of a cantilever beam piezoelectric motor of a piezoelectric speaker provided in an embodiment of the present invention;

[0034] Fig.18 is a schematic diagram of the low-frequency vibration amplitude of the cantilever beam piezoelectric motor of the piezoelectric speaker provided in an embodiment of the present invention;

[0035] Fig.19 is a schematic structural diagram of a folded beam piezoelectric motor of a piezoelectric speaker provided in an embodiment of the present invention;

[0036] Fig. 20 is a schematic diagram of the low-frequency vibration amplitude of the folded beam piezoelectric motor of the piezoelectric speaker provided in an embodiment of the present invention;

[0037] Fig.21 The figure is a comparison diagram of the sensitivity of the dual-diaphragm piezoelectric speaker provided according to the embodiment of the present invention and the single-diaphragm piezoelectric speaker in the prior art.

[0038] Reference numerals:

[0039] 10: housing; 110: upper cover; 120: middle frame; 121: frame body; 122: plate body; 1221: through hole; 130: lower cover; 131: through hole; 140: sound outlet hole; 141: sound outlet pipe; 150: back cover; 151: connection channel; 160: lead through hole; 170: conductive column;

[0040] 20: Piezoelectric module;

[0041] 210: piezoelectric motor; 211: substrate; 2111: through groove; 2112: "U"-shaped connecting arm; 212: piezoelectric sheet;

[0042] 220: first diaphragm assembly; 221: first diaphragm; 222: first middle sticker;

[0043] 230: second diaphragm assembly; 231: second diaphragm; 232: second middle sticker;

[0044] 240: first transmission component; 241: first transmission block; 242: transmission frame; 2421: reinforcement plate;

[0045] 250: second transmission component; 251: second transmission block; 252: transmission rod;

[0046] 30: first cavity;

[0047] 40: second cavity; 410: first cavity; 420: second cavity;

[0048] 50: the third cavity;

[0049] 60: elastic folding ring;

[0050] X: length direction of the shell / substrate;

[0051] Y: width direction of the housing / substrate. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the following will be described in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present invention, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented.

[0053] In the embodiments of the present invention, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0054] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0055] In addition, the terms "installed", "set", "provided with", "opened", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0057] An embodiment of the present invention provides a piezoelectric speaker, see Figure 1-Figure 8 , including a shell 10 and a piezoelectric module 20 arranged in the shell 10; the piezoelectric module 20 includes a piezoelectric motor 210, a first diaphragm assembly 220, a second diaphragm assembly 230, a first conduction assembly 240 and a second conduction assembly 250; wherein the first diaphragm assembly 220 and the second diaphragm assembly 230 are respectively arranged on both sides of the piezoelectric motor 210, the first conduction assembly 240 is arranged between the piezoelectric motor 210 and the first diaphragm assembly 220, and transmits the vibration of the piezoelectric motor 210 to the first diaphragm assembly 220; the second conduction assembly 250 is arranged between the piezoelectric motor 210 and the second diaphragm assembly 230, and transmits the vibration of the piezoelectric motor 210 to the second diaphragm assembly 230; and Furthermore, a first cavity 30 is formed between the first diaphragm assembly 220 and the inner wall of the shell 10, a second cavity 40 is formed between the first diaphragm assembly 220 and the second diaphragm assembly 230, and a third cavity 50 is formed between the second diaphragm assembly 230 and the inner wall of the shell 10; a partition structure is provided in the second cavity 40 to divide the second cavity 40 into a first cavity portion 410 and a second cavity portion 420 which are independent of each other, and the first cavity portion 410 is closer to the first diaphragm assembly 220, and the second cavity portion 420 is closer to the second diaphragm assembly 230; a sound outlet hole 140 is provided on the shell 10, and one end of the sound outlet hole 140 is connected to the outside of the shell 10, and the other end is connected to the first cavity 30 and the second cavity portion 420 respectively.

[0058] Compared with the prior art, the piezoelectric motor 210 of the embodiment of the present invention transmits vibration to the diaphragm assemblies on both sides thereof through the conduction components on both sides thereof, so that the first diaphragm assembly 220 vibrates and radiates to output high-frequency sound, and the second diaphragm assembly 230 vibrates and radiates to output low-frequency sound. The first cavity 410 and the third cavity 50 can play an auxiliary role in regulating the low-frequency part of the frequency response, so that the sound emitted by the speaker, especially the bass effect, is better, thereby improving the sensitivity of the speaker. It should be noted that the sound waves in the first cavity 410 and the third cavity 50 are superimposed with the in-phase sound waves in the first cavity 30 and the second cavity 420 to play an auxiliary role in regulating the sound emitted by the speaker. In addition, the sensitivity of a speaker refers to the efficiency of the speaker in converting electrical signals into sound.

[0059] Specifically, in the piezoelectric speaker, Figure 1-Figure 5 As shown, a sound outlet tube 141 may be provided at one end of the sound outlet hole 140 located outside the housing 10, so that the sound can be better output from the sound outlet tube 141, and the sound emitted by the piezoelectric motor 210 in cooperation with the first diaphragm assembly 220 through the first cavity 30 to the sound outlet hole 140 is high-pitched, and the sound emitted by the piezoelectric motor 210 in cooperation with the second diaphragm assembly 230 through the second cavity 420 to the sound outlet hole 140 is low-pitched. Figure 6 and Figure 7 As shown, the sound outlet 140 may be disposed on an end surface of the housing 10 , or may be disposed on a side surface of the housing 10 .

[0060] In addition, when the speaker is in operation, at low frequencies, since the sound pressures of the first cavity 410 and the second cavity 420 are in anti-phase form, in order to avoid sound short circuit, a partition structure needs to be provided to divide the second cavity 40 into the first cavity 410 and the second cavity 420 which are independent of each other.

[0061] Further, see Figure 8 The first diaphragm assembly 220 includes a first diaphragm 221 and a first middle sticker 222 attached to the first diaphragm 221. The first diaphragm 221 is a flexible film, the first middle sticker 222 is a rigid sheet, and the first middle sticker 222 is located on the side of the first diaphragm 221 away from the piezoelectric motor 210. The first transmission assembly 240 includes a first transmission block 241 and a transmission frame 242. One side of the first transmission block 241 abuts against one side of the piezoelectric motor 210, and the other side abuts against one side of the transmission frame 242. The other side of the transmission frame 242 abuts against the first diaphragm 221. In this way, the first middle sticker 222 provides support for the first diaphragm 221, and the first transmission block 241 and the transmission frame 242 are used to transmit the vibration of the piezoelectric motor 210 to the first diaphragm 221.

[0062] Specifically, the shape of the first transmission block 241 can be set to a rectangular, cylindrical or other shape, and the transmission frame 242 can be filled with a reinforcing plate 2421 or not filled with a reinforcing plate 2421 and present a frame shape. Moreover, when the transmission frame 242 is not filled with a reinforcing plate 2421 and presents a frame shape, the first transmission block 241 abuts against the frame of the transmission frame 242. In this embodiment, see Fig. 9 The transmission frame 242 is filled with a reinforcing plate 2421, and the reinforcing plate 2421 is provided with a plurality of holes penetrating the reinforcing plate 2421 along the thickness direction thereof, so as to ensure that the airflow can pass through the transmission frame 242. Furthermore, in order to ensure that the vibration energy transmitted by the first transmission block 241 is uniformly transmitted to the first diaphragm 221 through the transmission frame 242, the first transmission block 241 abuts against the center position of the reinforcing plate 2421 in the transmission frame 242.

[0063] Further, see Figure 8 The second diaphragm assembly 230 includes a second diaphragm 231 and a second middle sticker 232 attached to the second diaphragm 231. The second diaphragm 231 is a flexible film, the second middle sticker 232 is a rigid sheet, and the second middle sticker 232 is located on the side of the second diaphragm 231 away from the piezoelectric motor 210. The second transmission assembly 250 includes a second transmission block 251 and a transmission rod 252. One side of the second transmission block 251 abuts against the other side of the piezoelectric motor 210, and the other side abuts against one end of the transmission rod 252. The transmission rod 252 passes through the partition structure and the other end of the transmission rod 252 abuts against the second diaphragm 231. In this way, the second middle sticker 232 provides support for the second diaphragm 231, and the second transmission block 251 and the transmission rod 252 are used to transmit the vibration of the piezoelectric motor 210 to the second diaphragm 231.

[0064] Specifically, the shape of the second transmission block 251 can be set to a rectangular, cylindrical, etc. shape, and the second transmission block 251 can be the same as or different from the first transmission block 241. In this embodiment, the first transmission block 241 and the second transmission block 251 have the same shape, and the centers of the first transmission block 241 and the second transmission block 251 are located on the same straight line.

[0065] Further, see Figure 1-Figure 7The shell 10 includes an upper cover 110, a middle frame 120 and a lower cover 130. The middle frame 120 is arranged between the upper cover 110 and the lower cover 130, and a first cavity 30 is formed between the upper cover 110 and the first diaphragm 221, and a third cavity 50 is formed between the lower cover 130 and the second diaphragm 231; along the length direction A of the shell 10, the two sides of the piezoelectric motor 210 are respectively fixedly connected to the two sides of the inner wall of the middle frame 120; along the width direction B of the shell 10, there are gaps between the two sides of the piezoelectric motor 210 and the two sides of the inner wall of the middle frame 120, so that a second cavity 40 is formed between the first diaphragm 221 and the second diaphragm 231; and a lead through hole 160 is formed at a position corresponding to the piezoelectric motor 210 on the shell 10, and a conductive column 170 is sealed in the lead through hole 160, and one end of the conductive column 170 is connected to the piezoelectric motor 210, and the other end extends to the outside of the shell 10.

[0066] Specifically, the conductive column 170 is made of conductive materials such as copper and iron, and one end of the conductive column 170 is electrically connected to the piezoelectric motor 210, and the other end can be provided with a plug to facilitate electrical connection with an external power source. The external power source energizes the piezoelectric motor 210 through the conductive column 170, thereby enabling the speaker to start working. In addition, the upper cover 110, the middle frame 120, and the lower cover 130 can be connected by means of snap connection, screw connection, riveting, etc., which can be specifically set according to actual design and use requirements.

[0067] Further, see Figure 1 and Figure 10-13 The middle frame 120 includes a frame body 121 and a plate body 122 which are stacked in sequence along the thickness direction thereof. The frame body 121 is arranged above the plate body 122, and the piezoelectric motor 210 is fixedly connected to the frame body 121 on both sides along the length direction X; the plate body 122 is provided with a through hole 1221 along the thickness direction thereof; the partition structure is provided as an elastic folding ring 60, the elastic folding ring 60 is embedded and sealed in the through hole 1221, and the transmission rod 252 is embedded and sealed in the elastic folding ring 60. Since the transmission rod 252 needs to pass through the partition structure, and the transmission rod 252 needs to move up and down with the vibration motor, the partition structure is provided as an elastic folding ring 60 so that the elastic folding ring 60 can move up and down with the transmission rod 252, so as to avoid the partition structure affecting the up and down movement of the transmission rod 252. In addition, the stiffness of the elastic folding ring 60 can be adjusted by changing its thickness, shape, material and other factors.

[0068] Specifically, the frame portion 121 and the plate portion 122 can be fixedly connected by welding, screwing, etc., or can be integrally formed. A boss can be provided on the inner wall of the through hole 1221, so that the elastic folding ring 60 overlaps the boss, and the elastic folding ring 60 and the boss in the through hole 1221, as well as the elastic folding ring 60 and the transmission rod 252 can be sealed and fixedly connected by means of sealing adhesive bonding, welding, etc.

[0069] Further, see Figure 1 and Figure 2 The housing 10 further includes a rear cover 150, which is disposed on a side of the housing 10 away from the sound outlet 140, and a connecting channel 151 is formed on the inner wall of the rear cover 150, one end of the connecting channel 151 is connected to the first cavity 410, and the other end is connected to the third cavity 50, so that the first cavity 410 and the third cavity 50 are connected via the connecting channel 151. In this way, the connecting channel 151 disposed on the rear cover 150 connects the first cavity 410 and the third cavity 50, forming a larger adjustment cavity, so as to better adjust the sound effect, especially the bass effect, thereby improving the sensitivity of the speaker.

[0070] Specifically, the shape and position of the rear cover 150 can be set to Figure 1 The structure shown in the figure, that is, the frame part 121 and the upper cover 110 are protruded relative to the plate part 122 and the lower cover 130 in the length direction A of the housing 10 in the direction away from the sound outlet 140, the cross section of the rear cover 150 is "L" shaped, and the rear cover 150 is arranged in the protruding space of the frame part 121 and the upper cover 110 relative to the plate part 122 and the lower cover 130, and the first cavity 410 and the third cavity 50 are connected through the connecting channel 151 ( Figure 1 In addition, the two sides of the rear cover 150 can be fixedly connected to the frame portion 121 and the lower cover 130 by means of snap connection, screw connection, riveting, etc. At this time, the lead through hole 160 and the conductive column 170 disposed in the lead through hole 160 are disposed on the middle frame 120. The volume of the adjustment cavity is the sum of the volumes of the first cavity portion 410, the third cavity 50 and the connecting channel 151.

[0071] The shape and position of the rear cover 150 can also be set to Figure 2 The structure shown in FIG. 1 is that the rear cover 150 is disposed on a side of the housing 10 away from the sound outlet 140, and the rear cover 150 is fixedly connected to the upper cover 110 and the lower cover 130 on both sides along the thickness direction of the housing 10, respectively, and the first cavity 410 and the third cavity 50 are connected through the connecting channel 151 ( Figure 2In addition, the back cover 150 can be fixedly connected to the upper cover 110 and the lower cover 130 by means of snap connection, screw connection, riveting, etc. At this time, the lead through hole 160 and the conductive column 170 disposed in the lead through hole 160 are disposed on the back cover 150. The volume of the adjustment cavity is the sum of the volumes of the first cavity 410, the third cavity 50 and the connecting channel 151, because Figure 2 The volume of the connecting channel 151 shown is greater than Figure 1 The volume of the connecting passage 151 shown in the figure is larger than that of the adjusting chamber, and the larger the volume of the adjusting chamber, the better the adjusting effect on the bass. Therefore, the shape and position of the rear cover 150 are set as follows: Figure 2 In the structure shown, the volume of the adjustment chamber is larger, and the adjustment effect on the sound, especially the bass, is better.

[0072] In another embodiment, see Figure 3 , a through hole 131 is provided on one side of the lower cover 130 away from the sound outlet 140, and one end of the through hole 131 is connected to the third cavity 50, and the other end is connected to the outside of the shell 10. In this way, the third cavity 50 is connected to the outside of the shell 10 through the through hole 131, forming a larger adjustment cavity to better adjust the sound effect, especially the bass effect, thereby improving the sensitivity of the speaker. That is to say, the shell 10 in this embodiment is not provided with a rear cover 150, and the third cavity 50 is directly connected to the space outside the shell 10 through the through hole 131. The volume of the adjustment cavity is the volume of the first cavity part 410, the third cavity 50 and the space outside the shell 10. Under this setting, the volume of the adjustment cavity is the largest, and the adjustment effect on the sound, especially the bass, is the best.

[0073] Further, see Fig.14 and Fig.15 The vibration motor includes a substrate 211 and two piezoelectric sheets 212. The two piezoelectric sheets 212 are respectively arranged on both sides of the substrate 211 along the thickness direction thereof to form a flat motor. Fig.16 This is a schematic diagram of the low-frequency vibration amplitude of the flat motor. It can be seen from the figure that the low-frequency vibration amplitude of the flat motor is between 0-3.2μm.

[0074] See also Fig.17 Two through grooves 2111 are arranged on the substrate 211 of the flat motor, penetrating the substrate 211 along the thickness direction of the substrate 211. The through grooves 2111 extend along the width direction B of the substrate 211, and along the length direction A of the substrate 211, the two through grooves 2111 are arranged at intervals on the substrate 211 near the two sides of the piezoelectric sheet 212, so that the substrate 211 is cantilevered to form a cantilever beam piezoelectric motor. Fig.18 It is a schematic diagram of the low-frequency vibration amplitude of the cantilever piezoelectric motor. It can be seen from the figure that the low-frequency vibration amplitude of the cantilever piezoelectric motor is between 0-7.2μm.

[0075] See also Fig.19 Four "U"-shaped connecting arms 2112 are arranged on the substrate 211 of the cantilever beam piezoelectric motor, and each "U"-shaped connecting arm 2112 is respectively arranged on both sides of the substrate 211 along the width direction B, and is corresponding to the two sides of each through groove 2111 along the width direction B; and the open end of the "U"-shaped connecting arm 2112 is connected to the side of the substrate 211 along the width direction B, and the closed end of the "U"-shaped connecting arm 2112 extends into the through groove 2111 along the width direction B, so that the substrate 211 can be bent along the "U"-shaped connecting arm 2112 to form a folded beam piezoelectric motor. Fig. 20 It is a schematic diagram of the low-frequency vibration amplitude of the folded beam piezoelectric motor. It can be seen from the figure that the low-frequency vibration amplitude of the folded beam motor is between 0-8μm.

[0076] Therefore, by changing the structure of the substrate 211 on the piezoelectric motor 210 to form different types of piezoelectric motors 210, designers can set different types of piezoelectric motors 210 according to actual requirements for the low-frequency vibration amplitude. Different types of piezoelectric motors 210 are matched with the above-mentioned Figure 1-Figure 3 The shell 10 has different adjustment cavity volumes to design speakers with different bass effects, thereby increasing the diversity of speaker design.

[0077] In addition, in the MEMS (micro-electromechanical system) processing technology, silicon and its derivatives are generally used as substrates, and a single layer or multiple layers of piezoelectric materials and electrodes are deposited on the substrate using silicon micromachining technology, and finally an etching technology is used to release and generate a piezoelectric motor. Therefore, the piezoelectric motor 210 in the embodiment of the present invention can be processed by a silicon micromachining process to deposit a single layer or multiple layers of piezoelectric materials and electrodes on one side or both sides of the substrate 211 along its thickness direction to form the piezoelectric motor 210. In addition, the piezoelectric motor 210 can also be formed by other processing techniques, which is not specifically limited in this embodiment.

[0078] The working process of the speaker is as follows: the external power supply energizes the piezoelectric motor 210 through the conductive column 170, the piezoelectric motor 210 starts to vibrate, and transmits the vibration to the first diaphragm 221 through the first transmission block 241 and the transmission frame 242, and transmits the vibration to the second diaphragm 231 through the second transmission block 251 and the transmission rod 252, so that the first cavity 30, the first cavity 410, the second cavity 420 and the third cavity 50 radiate sound waves, and the sound waves in the first cavity 410 and the third cavity 50 in the same direction as those in the first cavity 30 and the second cavity 420 are superimposed, so as to enhance the sound emitted by the first cavity 30 and the second cavity 420 through the sound outlet 140, especially the bass. Fig. 20It can be clearly seen from the figure that the sensitivity of the single-diaphragm speaker in the prior art at lower frequencies is always lower than the sensitivity of the dual-diaphragm speaker in the present application, so the speaker in the present application has the advantage of higher sensitivity.

[0079] The "piezoelectric speaker" provided in the embodiment of the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation of the present invention. The description of the above implementation is only used to help understand the idea of ​​the present invention. There may be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A piezoelectric speaker, characterized in that: It comprises a shell and a piezoelectric module arranged in the shell; The piezoelectric module includes a piezoelectric motor, a first diaphragm assembly, a second diaphragm assembly, a first conduction assembly and a second conduction assembly; wherein, The first diaphragm assembly and the second diaphragm assembly are respectively arranged on both sides of the piezoelectric motor, the first conduction assembly is arranged between the piezoelectric motor and the first diaphragm assembly, and transmits the vibration of the piezoelectric motor to the first diaphragm assembly; the second conduction assembly is arranged between the piezoelectric motor and the second diaphragm assembly, and transmits the vibration of the piezoelectric motor to the second diaphragm assembly; and, A first cavity is formed between the first diaphragm assembly and the inner wall of the housing, a second cavity is formed between the first diaphragm assembly and the second diaphragm assembly, and a third cavity is formed between the second diaphragm assembly and the inner wall of the housing; A partition structure is provided in the second cavity to divide the second cavity into a first cavity portion and a second cavity portion which are independent of each other, and the first cavity portion is closer to the first diaphragm assembly, and the second cavity portion is closer to the second diaphragm assembly; The shell is provided with a sound outlet hole, and one end of the sound outlet hole is communicated with the outside of the shell, and the other end of the sound outlet hole is communicated with the first cavity and the second cavity respectively.

2. The piezoelectric speaker according to claim 1, wherein: The first diaphragm assembly includes a first diaphragm and a first middle sticker attached to the first diaphragm, the first diaphragm is a flexible film, the first middle sticker is a rigid sheet, and the first middle sticker is located on a side of the first diaphragm away from the piezoelectric motor; The first transmission component includes a first transmission block and a transmission frame. One side of the first transmission block abuts against one side of the piezoelectric motor and the other side abuts against one side of the transmission frame. The other side of the transmission frame abuts against the first diaphragm.

3. The piezoelectric speaker according to claim 2, wherein: The second diaphragm assembly includes a second diaphragm and a second middle sticker attached to the second diaphragm, the second diaphragm is a flexible film, the second middle sticker is a rigid sheet, and the second middle sticker is located on a side of the second diaphragm away from the piezoelectric motor; The second transmission component includes a second transmission block and a transmission rod, one side of the second transmission block abuts against the other side of the piezoelectric motor and the other side abuts against one end of the transmission rod, the transmission rod passes through the partition structure and the other end of the transmission rod abuts against the second diaphragm.

4. The piezoelectric speaker according to claim 3, characterized in that The housing comprises an upper cover, a middle frame and a lower cover, wherein the middle frame is disposed between the upper cover and the lower cover, and the first cavity is formed between the upper cover and the first diaphragm, and the third cavity is formed between the lower cover and the second diaphragm; Along the length direction of the shell, two sides of the piezoelectric motor are respectively fixedly connected to two sides of the inner wall of the middle frame; along the width direction of the shell, there are gaps between the two sides of the piezoelectric motor and the two sides of the inner wall of the middle frame, so that the second cavity is formed between the first diaphragm and the second diaphragm; and, A lead through hole is formed on the shell at a position corresponding to the piezoelectric motor, a conductive column is sealed in the lead through hole, one end of the conductive column is connected to the piezoelectric motor, and the other end extends to the outside of the shell.

5. The piezoelectric speaker according to claim 4, characterized in that The middle frame includes a frame body portion and a plate body portion stacked in sequence along the thickness direction thereof, the frame body portion is arranged above the plate body portion, and the piezoelectric motor is fixedly connected to the frame body portion at both sides along the length direction; the plate body portion is provided with a through hole along the thickness direction thereof; The separation structure is configured as an elastic folding ring, the elastic folding ring is embedded and sealed in the through hole, and the transmission rod is embedded and sealed in the elastic folding ring.

6. The piezoelectric speaker according to claim 4, wherein: The shell also includes a back cover, which is arranged on a side of the shell away from the sound outlet, and a connecting channel is formed on the inner wall of the back cover, one end of the connecting channel is connected to the first cavity, and the other end is connected to the third cavity, so that the first cavity and the third cavity are connected via the connecting channel.

7. The piezoelectric speaker according to claim 4, wherein: A through hole is provided on one side of the lower cover away from the sound outlet, and one end of the through hole is communicated with the third cavity, and the other end of the through hole is communicated with the outside of the shell.

8. The piezoelectric speaker according to any one of claims 1 to 7, characterized in that: The vibration motor includes a substrate and two piezoelectric sheets, and the two piezoelectric sheets are respectively arranged on both sides of the substrate along the thickness direction thereof.

9. The piezoelectric speaker according to claim 8, characterized in that Two through grooves are formed on the substrate and penetrate the substrate along the thickness direction of the substrate. The through grooves extend along the width direction of the substrate, and along the length direction of the substrate, the two through grooves are spaced apart on the substrate near the two sides of the piezoelectric sheet, so that the substrate is cantilevered.

10. The piezoelectric speaker according to claim 9, characterized in that The substrate is also provided with four "U"-shaped connecting arms, each of which is respectively provided on two sides of the substrate along the width direction and corresponding to two sides of each through groove along the width direction; and, The open end of the "U"-shaped connecting arm is connected to the side of the substrate along the width direction, and the closed end of the "U"-shaped connecting arm extends into the through groove along the width direction, so that the substrate can be bent along the "U"-shaped connecting arm.

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