WO2022022561A1

WO2022022561A1 - Piezoelectric type electroacoustic device and electronic apparatus

Info

Publication number: WO2022022561A1
Application number: PCT/CN2021/108917
Authority: WO
Inventors: 刘石磊; 辜磊; 黎椿键
Original assignee: 华为技术有限公司
Priority date: 2020-07-31
Filing date: 2021-07-28
Publication date: 2022-02-03
Also published as: CN114067773B; CN114067773A

Abstract

A piezoelectric type electroacoustic device (20), comprising a piezoelectric sheet (23), a transmission part (24), and a hard vibration plate (21). The piezoelectric sheet (23) and the hard vibration plate layer (21) are stacked and spaced apart, the piezoelectric sheet (23) comprises a vibration region, and the area of the hard vibration plate (21) is greater than that of the vibration region; the transmission part (24) is provided between the center of the vibration region and the hard vibration plate (21), and is fixedly connected to the hard vibration plate (21); the vibration region is used for vibrating to induce vibration of the transmission part (24), so that the transmission part (24) drives the hard vibration plate (21) to vibrate. Also provided is an electronic apparatus (10), comprising housings (12, 13), and the piezoelectric type electroacoustic device (20). The housings (12, 13) have a sound outlet hole (12b) communicating the inside and the outside of the housings (12, 13); the piezoelectric type electroacoustic device (20) is mounted in the housings (12, 13), and can produce sound by means of the sound outlet hole (12b). The piezoelectric type electroacoustic device (20) can improve the low-frequency performance.

Description

Piezoelectric electroacoustic devices and electronic equipment

This application claims the priority of the Chinese patent application with the application number 202010757438.X and the application name "piezoelectric electroacoustic device and electronic equipment" filed with the China Patent Office on July 31, 2020, the entire contents of which are incorporated by reference in this application.

technical field

The present application relates to the audio field of terminal equipment, and in particular, to a piezoelectric electro-acoustic device and electronic equipment.

Background technique

Piezoelectric speakers have been widely used in electronic devices such as mobile phones. When the piezoelectric speaker is working, the vibrating membrane will vibrate, which in turn pushes the air to vibrate to produce sound. In a conventional piezoelectric speaker, only a local area of the diaphragm can vibrate, so that the amount of air that the diaphragm can push is insufficient, which results in poor low-frequency performance of the conventional piezoelectric speaker.

SUMMARY OF THE INVENTION

The present application provides a piezoelectric electro-acoustic device and an electronic device including the piezoelectric electro-acoustic device. The piezoelectric electro-acoustic device can push a larger amount of air and has better low-frequency performance.

In a first aspect, the present application provides a piezoelectric electro-acoustic device, comprising a piezoelectric sheet, a transmission part and a hard vibration plate; the piezoelectric sheet and the hard vibration plate are stacked and arranged at intervals, and the piezoelectric sheet includes a vibration area, The area of the hard vibration plate is larger than the area of the vibration area; the transmission part is set between the center of the vibration area and the hard vibration plate, and is fixedly connected with the hard vibration plate; the vibration area is used for vibration to cause the transmission part to vibrate and make the transmission part vibrate. The part drives the hard vibration plate to vibrate.

In the present application, the piezoelectric sheet and the rigid vibration plate are spaced apart and may be substantially parallel. The piezoelectric sheet can vibrate when it is energized, and the area where the vibration occurs is called the vibration area. The vibration region may be the vibration region of the piezoelectric sheet in any order vibration mode. The center of the vibration area may be the position where the maximum vibration displacement occurs in the vibration area, or may be an area within a certain range around the maximum vibration displacement. The rigid vibration plate can have a large modulus and is not easily deformed. One end of the transmission part may or may not be in direct contact with the center of the vibration area.

In the present application, the piezoelectric sheet is used as a driving element, and the transmission part can transmit vibration, thereby driving the hard vibration plate to vibrate (the hard vibration plate is equivalent to a piston, and its vibration is equivalent to the reciprocating movement of the piston). The hard vibration plate can push the air to vibrate when it vibrates. Since the area of the hard vibration plate is large and the area of the vibration area is small, the vibration of the small area of the piezoelectric sheet can drive the vibration of the large area of the hard vibration plate, thereby driving more air to vibrate. Therefore, the low frequency performance of the piezoelectric electroacoustic device is better.

In an implementation manner of the first aspect, the area of the hard vibration plate is greater than or equal to the area of the piezoelectric sheet. Since the vibration area of the piezoelectric sheet is a part of the piezoelectric sheet, the design of this implementation can ensure that the area of the hard vibration plate is always larger than the area of the vibration area of the piezoelectric sheet, so that the hard vibration plate can be used for piston vibration. .

In an implementation of the first aspect, at least a portion of the vibration area overlaps the hard vibration plate. The surface of the hard vibration plate facing the piezoelectric sheet is used as the projection surface, and the orthographic projection of the vibration area on the projection surface all falls on the hard vibration plate, that is, the hard vibration plate can completely cover the vibration area. Alternatively, a part of the orthographic projection of the vibration area on the projection plane falls on the hard vibration plate, and the other part falls outside the hard vibration plate, that is, the hard vibration plate may be misaligned with the vibration area. The design of this implementation mode can reduce the size of the transmission part, ensure accurate and reliable transmission, and ensure that the hard vibration plate can stably vibrate the piston.

In an implementation manner of the first aspect, the modulus of the rigid vibration plate is greater than or equal to 1 GPa. This kind of hard vibration plate is relatively hard, not easy to bend and deform, and can stably vibrate the piston.

In an implementation manner of the first aspect, the material of the rigid vibration plate is a composite material composed of polymethacrylimide foam and aluminum, a composite material composed of polymethacrylimide foam and aluminum alloy, a Composite materials composed of methacrylimide foam and carbon fiber, composite materials composed of polymethacrylimide foam and glass fiber, composite materials composed of balsa wood and aluminum, composite materials composed of balsa wood and aluminum alloy, hair Any one of foamed aluminum and foamed aluminum alloy. The rigid vibration plate made of the above materials is lighter and more rigid, and has sufficient structural strength and good vibration performance.

In an implementation manner of the first aspect, the transmission part is an integral part, that is, the transmission part can be an integral part independent of the piezoelectric sheet and the hard vibration plate, and can be assembled to the piezoelectric sheet and the hard vibration plate between. This design can realize the modular manufacture of piezoelectric electroacoustic devices, which is convenient for debugging and maintenance.

In an implementation manner of the first aspect, the transmission part and the hard vibration plate are integrally connected, that is, the transmission part and the hard vibration plate are integrally formed. Such a design can reduce the difficulty of assembly and improve the reliability of the piezoelectric electroacoustic device.

In an implementation of the first aspect, the transmission part includes a support and at least two transmission rods; the support includes a force-applying end and a linkage end, and the force-applying end of the support is located between the rigid vibration plate and the linkage end of the support; at least The two transmission rods are arranged at different planes from each other; the transmission rod is fixedly connected with the force-applying end of the support, and is inclined with the hard vibration plate; the transmission rod includes a fulcrum end and a transmission end, and the fulcrum end of the transmission rod and the transmission end of the transmission rod It is arranged on both sides of the force-applying end of the support, and the distance between the force-applying end of the support and the fulcrum end of the transmission rod is smaller than the distance between the force-applying end of the support and the transmission end of the transmission rod; the transmission end of the transmission rod and the hard vibration The plate is fixedly connected; the vibration area is used to vibrate to cause the linkage end of the support and the force end of the support to vibrate, so that the force end of the support drives the transmission end of the transmission rod to rotate around the fulcrum end of the transmission rod, so that the transmission end of the transmission rod drives the Hard vibration plate vibrates.

In this implementation manner, the transmission part is a mechanism capable of performing mechanism motion. The mounts are used to support and directly drive the transmission rod. The support can be approximated as a ring-shaped structure surrounding a circumference, such as a circular ring, a square ring, a special-shaped ring, and the like. The support can also be other structures, such as plate, column or block. The force-applying end and the linkage end are two opposite parts of the support, and the linkage end is close to the vibration area and can vibrate with the vibration area, so that the force-applying end vibrates accordingly. The transmission rod is a rod-shaped part. Any two transmission rods are neither parallel nor intersecting, and can be regarded as straight lines. The transmission rod is fixedly connected with the force application end of the support, and the fixed connection position on the transmission rod with the force application end is located between the fulcrum end of the transmission rod and the transmission end. The transmission rod and the support can form a lever mechanism, wherein when the force-applying end vibrates, the transmission end of the transmission rod is driven to rotate around the fulcrum end. The transmission end will drive the rigid vibrating plate to vibrate, so that the rigid vibrating plate acts as a piston to vibrate. Since the force-applying end is closer to the fulcrum end and the transmission end is farther from the fulcrum end, the vibration displacement of the transmission rod at the force-applying end (basically equal to the displacement of the vibration area) is small, while the vibration displacement of the transmission end of the transmission rod is large, that is, the The solution of the implementation can amplify the small vibration displacement of the vibration area into the large vibration displacement of the hard vibration plate. This displacement amplification effect can further increase the amount of air pushed, thereby improving the low-frequency performance of the piezoelectric electroacoustic device.

In an implementation manner of the first aspect, the transmission rod is set as a straight generatrix with a single-leaf hyperboloid. The transmission rod can be used as the straight generatrix of the single-leaf hyperboloid. When the number of transmission rods is large, all the transmission rods can approximately form a single-leaf hyperboloid. The single-page hyperboloid design can well realize the mechanism movement between the support and the transmission rod, and the transmission is reliable, which can ensure that the hard vibration plate can reliably vibrate the piston.

In an implementation of the first aspect, the transmission part includes a rotating shaft and a transmission arm; the rotating shaft is arranged between the hard vibration plate and the piezoelectric sheet; the transmission arm is rotatably connected to the rotating shaft, and the transmission arm includes a linkage end and a transmission end, and the transmission The linkage end of the arm and the transmission end of the transmission arm are located on both sides of the rotating shaft. The distance between the linkage end of the transmission arm and the rotating shaft is smaller than the distance between the transmission end of the transmission arm and the rotating shaft. Fixed connection; the vibration area is used to vibrate to cause the linkage end of the transmission arm to vibrate, so that the transmission end of the transmission arm rotates around the rotating shaft, so that the transmission end of the transmission arm drives the hard vibration plate to vibrate.

In this implementation manner, the transmission part is a lever mechanism capable of mechanical movement. Fixed shaft settings. The linkage end of the transmission arm can vibrate with the vibration of the vibration area, so that the transmission end of the transmission arm rotates around the rotating shaft, thereby driving the rigid vibration plate to vibrate. Since the linkage end is closer to the rotating shaft and the transmission end is farther from the rotating shaft, the solution of this implementation mode can amplify the smaller vibration displacement of the vibration area into the larger vibration displacement of the hard vibration plate. This displacement amplification effect can further increase the amount of air pushed, thereby improving the low-frequency performance of the piezoelectric electroacoustic device. In addition, the lever mechanism has a simple structure, is easy to manufacture and assemble, and has good product reliability.

In an implementation of the first aspect, the transmission arm includes a connection arm, the connection arm connects the linkage end and the transmission end; the connection arm is rotatably connected to the rotating shaft; the linkage end and the transmission end are arranged at an angle with the connection arm. In this implementation, the transmission arm is connected to the linkage end and the transmission end by bending, the angle between the transmission arm and the linkage end is not limited to a right angle, and the angle between the transmission arm and the transmission end is not limited to a right angle. The transmission arm has a simple structure and reliable transmission.

In an implementation of the first aspect, the piezoelectric electro-acoustic device includes an isolation membrane and a gasket; the isolation membrane is an elastic material; the isolation membrane and the hard vibration plate are stacked and arranged, and the isolation membrane is located on the hard vibration plate away from the piezoelectric sheet one side; the gasket is located between the isolation diaphragm and the piezoelectric sheet, the gasket connects the periphery of the isolation diaphragm and the peripheral edge of the piezoelectric sheet, and forms a closed cavity with the isolation film and the piezoelectric sheet; the hard vibration plate and the transmission part set in the cavity.

In this implementation manner, the isolation film may be substantially in the shape of a flat sheet. The separator can be made of elastic materials, including but not limited to polyurethane (PU), thermoplastic polyurethanes (TPU), rubber, silicone, polyethylene terephthalate (PET), polyether acyl Imine (polyetherimide, PEI) and the like. The peripheral edge of the rigid vibration plate is indented within the peripheral edge of the isolation diaphragm. The isolation film will be driven by the hard vibrating plate and vibrate following the vibration of the hard vibrating plate. The isolation film made of elastic material has a good sealing effect, which can well isolate the front cavity and the rear cavity of the piezoelectric electro-acoustic device, and block the air flow between the front cavity and the rear cavity, thereby avoiding the phenomenon of acoustic short circuit. The isolation film can also play the role of suspending the hard vibration plate and provide elastic restoring force to the hard vibration plate to ensure that the hard vibration plate can vibrate stably. In addition, using the isolation film beyond the boundary of the rigid vibration plate to pull the rigid vibration plate, this structure is relatively easy to manufacture, which makes the solution of this implementation mode high in manufacturability and easy for products to fall to the ground.

In an implementation manner of the first aspect, the area of the isolation membrane between the washer and the hard vibration plate is curved and arched. The curved and arched part can be called a folded ring. The folded ring can reduce the vibration resistance of the rigid vibration plate, so that the rigid vibration plate can basically remain flat during the vibration process without bending and deformation, ensuring that the rigid vibration plate is It can do piston movement, which is beneficial to ensure the acoustic effect of piezoelectric electroacoustic devices. In addition, the folding ring can also suspend the rigid vibration plate and provide elastic restoring force, so that it can be maintained in the set position.

In an implementation manner of the first aspect, the piezoelectric electro-acoustic device includes a washer, the washer is an elastic material, the washer is located between the hard vibration plate and the piezoelectric sheet, and the washer connects the periphery of the hard vibration plate and the piezoelectric sheet The peripheral edge of the vibration plate and the hard vibration plate and the piezoelectric sheet form a closed cavity; the transmission part is arranged in the cavity.

In this implementation manner, the material of the gasket includes, but is not limited to, ethylene-vinyl acetate copolymer (EVA), rubber, silica gel, foam (which can be glued), and the like. These elastic materials are elastic and relatively soft. The gasket can be thinner, eg 0.2mm-1mm thick. The washer may be a surrounding frame. The gasket can play the role of supporting and fixing the hard vibration plate, and can also seal the gap between the hard vibration plate and the piezoelectric sheet to avoid air leakage (if there is air leakage, the sound wave cannot be conducted according to the design requirements, which will affect the sound). Due to the elastic properties of the washer, the washer can also provide elastic restoring force to the hard vibration plate, and ensure that the periphery of the hard vibration plate has sufficient degrees of freedom, so that the hard vibration plate can vibrate fully and reliably.

In an implementation of the first aspect, the piezoelectric electro-acoustic device includes a vibrating membrane and a washer; the vibrating membrane and the piezoelectric sheet are stacked and arranged, the piezoelectric sheet is located on one side or both sides of the vibrating membrane, and the peripheral edge of the piezoelectric sheet is It shrinks on the periphery of the diaphragm; the washer is located between the hard vibration plate and the piezoelectric sheet, the washer connects the periphery of the hard vibration plate and the periphery of the diaphragm, and forms a closed cavity with the hard vibration plate and the diaphragm ; The transmission part is arranged in the cavity.

In this implementation manner, the vibrating film and the piezoelectric sheet can be stacked and basically attached (the thickness directions of the two are basically the same). The piezoelectric sheet may be located between the vibrating membrane and the hard vibrating plate, or on the side of the vibrating membrane facing away from the hard vibrating plate, or there may be piezoelectric sheets on both sides of the vibrating membrane. The periphery of the piezoelectric sheet shrinks within the periphery of the diaphragm, which reduces the constraints on the edge of the piezoelectric sheet and reduces the vibration resistance of the piezoelectric sheet, so that the vibration displacement of the piezoelectric sheet can be increased, thereby making the The vibration displacement of the hard vibration version is increased. This is beneficial to increase the amount of air that the piezoelectric electro-acoustic device can push, thereby further enhancing the low-frequency performance and overall sound quality performance of the piezoelectric electro-acoustic device. The gasket can play the role of supporting and fixing the hard vibration plate, and can also seal the gap between the hard vibration plate and the piezoelectric sheet to avoid air leakage. The washer can also provide elastic restoring force to the hard vibrating plate, and ensure that the peripheral edge of the hard vibrating plate has sufficient degrees of freedom, so that the hard vibrating plate can vibrate fully and reliably.

In an implementation manner of the first aspect, the area of the diaphragm between the washer and the piezoelectric sheet is curved and arched. The curved and arched part can be called a folded ring. The folded ring reduces the vibration resistance of the piezoelectric sheet, so that the vibration displacement of the piezoelectric sheet can be increased, which in turn increases the vibration displacement of the hard vibration plate, which is conducive to improving the piezoelectricity. The amount of air that can be pushed by the piezoelectric electro-acoustic device further enhances the low-frequency performance and overall sound quality performance of the piezoelectric electro-acoustic device. In addition, the ring can also suspend the piezoelectric sheet and provide elastic restoring force to keep it in the set position.

In an implementation manner of the first aspect, the diaphragm is provided with a through hole, and the through hole communicates with the cavity. The through hole can connect the back cavity of the piezoelectric electro-acoustic device with the cavity between the diaphragm and the hard vibration plate, which is equivalent to expanding the back cavity of the piezoelectric electro-acoustic device and can increase the piezoelectric electro-acoustic device. The low-frequency resonance of the acoustic device improves the low-frequency performance of the piezoelectric electro-acoustic device.

In an implementation manner of the first aspect, the piezoelectric electro-acoustic device includes an isolation diaphragm, a gasket and a vibrating diaphragm; the isolation diaphragm is an elastic material; the isolation diaphragm, the hard vibration plate and the diaphragm are stacked in sequence; Between the piezoelectric sheet, the gasket connects the periphery of the isolation diaphragm and the diaphragm, and forms a closed cavity with the isolation diaphragm and the diaphragm; the piezoelectric sheet is located on one or both sides of the diaphragm; the hard vibration plate and the transmission part are both arranged in the cavity.

In this implementation, the isolation film and the vibration film are arranged at the same time, which can well isolate the front cavity and the rear cavity of the piezoelectric electro-acoustic device, and block the air flow between the front cavity and the rear cavity, thereby avoiding the phenomenon of acoustic short circuit. It can play the role of suspending the hard vibration plate and provide elastic restoring force to the hard vibration plate to ensure that the hard vibration plate can vibrate stably; it can make the periphery of the piezoelectric sheet shrink within the periphery of the diaphragm, Reduce the constraints on the edge of the piezoelectric sheet and reduce the vibration obstruction of the piezoelectric sheet, so that the vibration displacement of the piezoelectric sheet can be increased, thereby increasing the vibration displacement of the hard vibration plate, which is conducive to improving piezoelectric electroacoustic devices. The amount of air that can be pushed, thereby further enhancing the low frequency performance and overall sound quality performance of the piezoelectric electroacoustic device.

In an implementation manner of the first aspect, the piezoelectric electro-acoustic device includes a back shell, which is arranged on the side of the piezoelectric sheet away from the hard vibration plate; the back shell is connected to the periphery of the piezoelectric sheet and is connected to the piezoelectric sheet. The electric sheet surrounds the back cavity of the piezoelectric electroacoustic device. The piezoelectric electro-acoustic device of this implementation has its own back shell, and the back cavity is its internal space. The piezoelectric electro-acoustic device is relatively modular, easy to be assembled with the casing of the electronic equipment, and the working reliability is not easily affected by the assembly.

In an implementation manner of the first aspect, the piezoelectric electro-acoustic device includes a rear shell, which is arranged on the side of the diaphragm away from the hard vibration plate; the rear shell is connected to the periphery of the diaphragm, and is connected to the surrounding into the back cavity of the piezoelectric electroacoustic device. The piezoelectric electro-acoustic device of this implementation has its own back shell, and the back cavity is its internal space. The piezoelectric electro-acoustic device is relatively modular, easy to be assembled with the casing of the electronic equipment, and the working reliability is not easily affected by the assembly.

In an implementation manner of the first aspect, the piezoelectric electro-acoustic device includes a front case, and the front case is disposed on the side of the hard vibration plate away from the piezoelectric sheet; the front case is connected to the periphery of the hard vibration plate, and is connected with the hard vibration plate. The hard vibration plate encloses the front cavity of the piezoelectric electroacoustic device. The piezoelectric electro-acoustic device of this implementation has its own front shell, and its front cavity is its internal space. The piezoelectric electro-acoustic device is relatively modular, easy to be assembled with the casing of the electronic equipment, and the working reliability is not easily affected by the assembly.

In an implementation manner of the first aspect, the piezoelectric electro-acoustic device includes a front case, and the front case is arranged on the side of the isolation diaphragm away from the hard vibration plate; the front case is connected to the periphery of the isolation diaphragm, and is surrounded by the isolation diaphragm. into the front cavity of the piezoelectric electroacoustic device. The piezoelectric electro-acoustic device of this implementation has its own front shell, and its front cavity is its internal space. The piezoelectric electro-acoustic device is relatively modular, easy to be assembled with the housing of the electronic equipment, and the working reliability is not easily affected by the assembly.

In an implementation manner of the first aspect, the vibration region is a vibration region of the piezoelectric sheet in a first-order mode. Due to the large vibration displacement of the vibration region in the first-order mode, it is beneficial to increase the amount of air pushed by the piezoelectric electro-acoustic device and improve the low-frequency performance of the piezoelectric electro-acoustic device.

In a second aspect, the present application provides an electronic device, including a housing and a piezoelectric electro-acoustic device; the housing has a sound outlet connecting the inside and outside of the housing; the piezoelectric electro-acoustic device is installed in the housing and can pass through The sound hole emits sound. In this application, the housing may be a single component, or may be an assembly assembled from several components. The front cavity of the piezoelectric electro-acoustic device can correspond to the sound outlet, and the sound waves generated by the piezoelectric electro-acoustic device can be transmitted from the front cavity to the sound outlet, and then propagated to the outside through the sound outlet. Since the piezoelectric electroacoustic device in the electronic device has better low frequency performance, the electronic device has better bass quality and better user experience.

In a third aspect, the present application provides an electronic device, including a housing and a piezoelectric electro-acoustic device; the housing has a sound outlet connecting the inside and outside of the housing, the piezoelectric electro-acoustic device is installed in the housing, and can pass through The sound outlet emits sound; the inner side of the housing has a first cover part, the first cover part is located on the side of the hard vibration plate away from the piezoelectric sheet; the first cover part is connected with the hard vibration plate or the periphery of the isolation film , and the front cavity of the piezoelectric electro-acoustic device is enclosed with a hard vibration plate or an isolation film.

In this application, the piezoelectric electro-acoustic device of the electronic device itself does not have a front shell, and the piezoelectric electro-acoustic device cooperates with the first cover part in the shell, and uses the first cover part as its own front shell to form a front cover. cavity. Wherein, for the piezoelectric electro-acoustic device without isolation film, the first cover part is connected with the periphery of the hard vibration plate, and forms a front cavity with the hard vibration plate. For a piezoelectric electro-acoustic device with an isolation film, the first cover part is connected to the periphery of the isolation film, and forms a front cavity with the isolation film. By using the first cover part as the front case of the piezoelectric electro-acoustic device, the design and manufacture of the piezoelectric electro-acoustic device can be simplified, and the device manufacturing cost can be reduced. In addition, since the piezoelectric electro-acoustic device does not have a front case, the thickness is small, which is beneficial to realize the thinning of the electronic device.

In a fourth aspect, the present application provides an electronic device, including a casing and a piezoelectric electro-acoustic device; the casing has a sound outlet connecting the inside and outside of the casing, the piezoelectric electro-acoustic device is installed in the casing, and can pass through the casing. The sound outlet emits sound; the inner side of the housing has a second cover part, the second cover part is located on the side of the piezoelectric sheet away from the hard vibration plate; the second cover part is connected with the peripheral edge of the piezoelectric sheet or the vibrating film, The rear cavity of the piezoelectric electro-acoustic device is enclosed with the piezoelectric sheet or the vibrating film.

In this application, the piezoelectric electro-acoustic device of the electronic device itself does not have a rear shell, and the piezoelectric electro-acoustic device cooperates with the second cover part in the shell, and uses the second cover part as its own rear shell, and forms a rear shell. cavity. Wherein, for a piezoelectric electro-acoustic device without a diaphragm, the second cover portion is connected to the periphery of the piezoelectric sheet, and forms a back cavity with the piezoelectric sheet. For a piezoelectric electro-acoustic device with a vibrating membrane, the second cover part is connected to the periphery of the vibrating membrane, and forms a back cavity with the vibrating membrane. By using the second cover portion as the back shell of the piezoelectric electro-acoustic device, the design and manufacture of the piezoelectric electro-acoustic device can be simplified, and the manufacturing cost of the device can be reduced. In addition, since the piezoelectric electro-acoustic device does not contain a back shell, the thickness is small, which is beneficial to realize the thinning of the electronic device.

Description of drawings

1 is a schematic diagram of the assembly structure of the electronic device according to the first embodiment;

Fig. 2 is the exploded structure schematic diagram of the electronic device in Fig. 1;

3 is a schematic three-dimensional structure diagram of the middle frame of the electronic device in FIG. 2 from another viewing angle;

Fig. 4 is the partial enlarged structure schematic diagram of C place in Fig. 3;

Fig. 5 is the partial enlarged structure schematic diagram of B place in Fig. 2;

Fig. 6 is the assembly structure schematic diagram of the piezoelectric electroacoustic device of the electronic device in Fig. 2;

Fig. 7 is the D-D sectional structure schematic diagram of the piezoelectric electroacoustic device in Fig. 6;

Fig. 8 is the exploded structure schematic diagram of the piezoelectric electroacoustic device in Fig. 6;

9 is a schematic plan view of the vibration region of the piezoelectric sheet of the piezoelectric electro-acoustic device in FIG. 8 in a first-order mode;

Fig. 10 is a cross-sectional structural schematic diagram of the vibration region of the piezoelectric sheet in Fig. 9;

FIG. 11 is a schematic diagram of the assembly relationship between the vibration area and the transmission part of the piezoelectric sheet in FIG. 10;

Figure 12 is a schematic diagram of the assembly relationship of the vibration area, the transmission part and the hard vibration plate of the piezoelectric sheet in Figure 11;

Fig. 13 is the A-A sectional structure schematic diagram of the electronic device in Fig. 1;

Fig. 14 is a partial enlarged structural schematic diagram at E in Fig. 13;

15 is a schematic diagram of the assembly structure of the piezoelectric electroacoustic device in the second embodiment;

Fig. 16 is the sectional structure schematic diagram of the piezoelectric electroacoustic device in Fig. 15;

17 is a schematic diagram of the assembly relationship between the piezoelectric electroacoustic device and the housing of the electronic device in the second embodiment;

18 is a schematic cross-sectional structure diagram of the piezoelectric electro-acoustic device in the third embodiment;

19 is a schematic diagram of the assembly relationship between the piezoelectric electroacoustic device and the housing of the electronic device in the third embodiment;

20 is a schematic cross-sectional structure diagram of the piezoelectric electro-acoustic device in the fourth embodiment;

21 is a schematic cross-sectional structure diagram of the piezoelectric electroacoustic device in the fifth embodiment;

22 is a schematic diagram of the exploded structure of the piezoelectric electroacoustic device in the fifth embodiment;

23 is a schematic diagram of the assembly relationship between the piezoelectric electroacoustic device and the housing of the electronic device in the fifth embodiment;

24 is a schematic cross-sectional structure diagram of the piezoelectric electroacoustic device in the sixth embodiment;

25 is a schematic cross-sectional structure diagram of the piezoelectric electroacoustic device in the seventh embodiment;

26 is a schematic cross-sectional structure diagram of the piezoelectric electroacoustic device in the eighth embodiment;

27 is a schematic diagram of the exploded structure of the piezoelectric electroacoustic device in the ninth embodiment;

28 is a schematic diagram of the assembly relationship between the piezoelectric electroacoustic device and the housing of the electronic device in the ninth embodiment;

Fig. 29 is the exploded structure schematic diagram of the piezoelectric electroacoustic device in the tenth embodiment;

Figure 30 is a schematic cross-sectional structure diagram of the piezoelectric electroacoustic device in the eleventh embodiment;

31 is a schematic diagram of the exploded structure of the piezoelectric electroacoustic device in the eleventh embodiment;

32 is a schematic diagram of an exploded structure of the electronic device in the twelfth embodiment;

Figure 33 is a schematic diagram of the assembly structure of the piezoelectric electroacoustic device of the electronic device in Figure 32;

Fig. 34 is the F-F cross-sectional structural schematic diagram of the piezoelectric electroacoustic device in Fig. 33;

Fig. 35 is the exploded structure schematic diagram of the piezoelectric electroacoustic device in Fig. 33;

36 is a schematic diagram of the assembly relationship between the piezoelectric electroacoustic device and the housing of the electronic device in the twelfth embodiment;

37 is a schematic three-dimensional structure diagram of the middle frame in the thirteenth embodiment;

38 is a schematic diagram of the assembly structure of the piezoelectric electroacoustic device in the thirteenth embodiment;

Figure 39 is a G-G cross-sectional structural schematic diagram of the piezoelectric electroacoustic device in Figure 38;

40 is a schematic diagram of the exploded structure of the piezoelectric electroacoustic device in the thirteenth embodiment;

Fig. 41 is a perspective view of the front case of the piezoelectric electro-acoustic device in Fig. 40;

42 is a schematic diagram of the assembly relationship between the piezoelectric electroacoustic device and the housing of the electronic device in the thirteenth embodiment;

43 is a schematic diagram of the assembly structure of the piezoelectric electroacoustic device in the fourteenth embodiment;

Fig. 44 is the H-H sectional structure schematic diagram of the piezoelectric electroacoustic device in Fig. 43;

Fig. 45 is the exploded structure schematic diagram of the piezoelectric electroacoustic device in Fig. 43;

46 is a schematic diagram of the assembly relationship between the piezoelectric electroacoustic device and the housing of the electronic device in the fourteenth embodiment;

47 is a schematic diagram of the assembly structure of the piezoelectric electroacoustic device in the fourteenth embodiment;

Fig. 48 is the I-I sectional structure schematic diagram of the piezoelectric electro-acoustic device in Fig. 47;

Fig. 49 is the exploded structure schematic diagram of the piezoelectric electroacoustic device in Fig. 47;

Figure 50 is a schematic diagram of the assembly structure of the transmission part of the piezoelectric electroacoustic device in Figure 49;

Figure 51 is a schematic diagram of the transmission rod of the transmission part in Figure 50 being approximated as a straight generatrix of a single-leaf hyperboloid;

Figure 52 is a schematic diagram of the assembly relationship of the transmission part, the hard vibration plate, the diaphragm and the piezoelectric sheet in the fourteenth embodiment;

Figure 53(a) is a simplified schematic diagram showing that the transmission part in the fourteenth embodiment is in a balanced position;

Figure 53(b) is a simplified schematic diagram showing that the transmission part in the fourteenth embodiment is in a vibrating position;

Figure 53 (c) is a simplified schematic diagram showing that the transmission part in the fourteenth embodiment is in another vibration position;

Figure 54 is a schematic diagram of the calculation of the vibration displacement of the transmission rod in the fourteenth embodiment;

55 is a schematic diagram of the assembly structure of the piezoelectric electroacoustic device in the fifteenth embodiment;

Fig. 56 is the exploded structure schematic diagram of the piezoelectric electroacoustic device in Fig. 55;

Fig. 57 is the exploded structure schematic diagram of the piezoelectric electroacoustic device in Fig. 55;

Figure 58 is a schematic diagram of the assembly structure of the transmission part of the piezoelectric electroacoustic device in Figure 57;

FIG. 59 shows the comparison of the low frequency performance curves of the piezoelectric electroacoustic device of the embodiment of the present application and the conventional piezoelectric electroacoustic device.

detailed description

The following embodiments of the present application provide an electronic device, which includes but is not limited to mobile phones, tablet computers, notebook computers, electronic readers, wearable devices (such as wireless earphones, smart clothing, smart watches), and the like. The following description will be given by taking the electronic device being a mobile phone as an example.

As shown in FIG. 1 and FIG. 2 , the electronic device 10 of the first embodiment may be a bar phone. A candy bar phone is relative to a foldable phone (or foldable phone, or a foldable phone), that is, a phone that cannot be folded and unfolded, and always remains flat. In other embodiments, the electronic device may also be a mobile phone with a folding screen.

As shown in FIGS. 1 and 2 , the electronic device 10 may include a display screen 11 , a middle frame 12 , a piezoelectric electro-acoustic device 20 and a back cover 13 , both of which belong to the housing of the electronic device 10 .

The display screen 11 can be a flat 2D screen, or a curved screen such as a 2.5D screen (the display screen 11 has a flat middle portion and curved portions connected on opposite sides of the middle portion) or a 3D screen (in a 2.5D screen). On the basis of the screen, the middle part is also made a curved surface). The display screen 11 may include a cover plate and a display panel, and the cover plate is laminated with the display panel. The cover plate is used to protect the display panel, and the display panel is used to display images. The display panel includes, but is not limited to, a liquid crystal display panel or an organic light emitting diode display panel. A touch unit may be integrated in the cover, that is, the cover has a touch function; or, the display panel may have a built-in touch unit, that is, the display panel has both display and touch functions. The electronic device 10 in the first embodiment has the display screen 11, which is only an example. In other embodiments, the electronic device may not have the display screen 11 .

The middle frame 12 is used as the main structural carrier of the electronic device 10 to carry the display screen 11 and the piezoelectric electroacoustic device 20 . As shown in FIG. 2 , an installation groove 12a may be formed on one side of the middle frame 12, and the display screen 11 is installed in the installation groove 12a. As shown in FIG. 3 , a side of the middle frame 12 facing away from the display screen 11 may be formed with an installation groove 12 c , and the installation groove 12 c is used to accommodate the piezoelectric electro-acoustic device 20 .

As shown in FIG. 3 and FIG. 4 , a first cover portion 121 may be provided in the installation groove 12c. For example, the first cover part 121 may include a first wall 121a, a second wall 121b and a third wall 121c which are connected in sequence, and the first wall 121a, the second wall 121b and the third wall 121c may enclose an approximately C-shaped open type wall structure. The first wall 121a, the second wall 121b and the third wall 121c are all protruding from the bottom surface 12d of the mounting groove 12c, and the first wall 121a and the third wall 121c at both ends are connected to the side surface 12e of the mounting groove 12c (the side surface 12e surrounds In the display screen 11, the normal of the side surface 12e can be parallel to the display screen 11). The first cover part 121 is used for connecting with the piezoelectric electro-acoustic device 20 and can be used as a front case of the piezoelectric electro-acoustic device 20 (which will be described later).

As shown in Fig. 2 and Fig. 4, a sound hole 12b may be provided on the middle frame 12, and the sound hole 12b penetrates the side surface 12e of the installation groove 12c to communicate the installation groove 12c with the outside world. The sound outlet hole 12b may include a plurality of small holes distributed in an array, or may be a single large hole. In the latter case, a dust filter can be installed in the sound outlet hole 12b. The second wall 121b may be opposite to the sound outlet hole 12b, and the first wall 121a and the third wall 121c may be located on two sides of the sound outlet hole 12b, respectively. The sound hole 12b is used to transmit the sound generated by the piezoelectric electro-acoustic device 20 (the description will be continued below).

In the first embodiment, the sound outlet hole 12b is opened on the side surface 12e of the middle frame 12, which is only an example. In other embodiments, the sound outlet hole 12b can also be opened at other suitable positions, for example, opened on the back cover 13 according to the needs of the product. According to needs, the structure of the first cover portion 121 can also be adjusted according to the position of the sound outlet 12b. For example, when the sound outlet hole 12b is opened on the rear shell 12, the first cover portion 121 can be connected to the side surface of the installation slot 12c. 12e are kept spaced and form a surrounding wall structure.

As shown in FIG. 2 , the rear cover 13 is mounted on the middle frame 12 and is located on the side of the middle frame 12 away from the display screen 11 . As shown in FIG. 2 and FIG. 3 , the rear cover 13 can close the mounting groove 12c, thereby encapsulating the piezoelectric electroacoustic device 20 in the mounting groove 12c. The structure of the back cover 13 shown in FIG. 2 is only a schematic representation, and the embodiment of the present application is not limited thereto.

As shown in FIG. 2 and FIG. 5 , the inner surface 13 a of the side of the rear cover 13 facing the middle frame 12 may be provided with a second cover portion 131 . The second cover part 131 may form a closed wall structure surrounding a circumference. For example, the second cover part 131 in FIG. 5 may include four walls 131a connected in sequence at the first place, and the four walls 131a may approximately form a box. The second cover part 131 is used for connecting with the piezoelectric electroacoustic device 20 and can be used as a rear case of the piezoelectric electroacoustic device 20 (which will be described later). In other embodiments, the second capping portion 131 may form an open wall structure (like a C shape).

6 , 7 and 8 , the piezoelectric electro-acoustic device 20 may include a piezoelectric sheet 23 , a transmission portion 24 , a hard vibration plate 21 and a washer 22 . The piezoelectric electro-acoustic device 20 may be a speaker or a receiver (or earpiece).

The piezoelectric sheet 23 can be in the shape of a flat plate, such as a square plate. The materials of the piezoelectric sheet 23 include but are not limited to piezoelectric ceramics such as lead zirconate titanate, lithium niobate, lithium tantalate, piezoelectric crystals such as quartz, and piezoelectric polymers such as polyvinylidene fluoride (PVDF). . In terms of construction, the piezoelectric sheet 23 includes, but is not limited to, single, multi-layer stacking in the same polarization direction, multi-layer stacking in the same polarization direction, and the like.

Piezoelectric electroacoustic device 20 may be electrically connected to audio circuitry in electronic device 10 . The audio circuit may include, for example, a codec, an intelligent power amplifier, etc. The codec and the intelligent power amplifier process the signal and output it to the piezoelectric electro-acoustic device 20 to make the piezoelectric electro-acoustic device 20 emit sound. Among them, the piezoelectric sheet 23 has electrodes, which can receive the signal output by the audio circuit. The signal can drive the piezoelectric sheet to deform in the direction of its own plane. Since the piezoelectric sheet 23 can be fixed on the second capping portion 131 (which will be described later), the piezoelectric sheet 23 is constrained by the second capping portion 131, so that the deformation of the piezoelectric sheet 23 in the plane direction is transformed into substantially along the Bending vibration in the thickness direction of the piezoelectric sheet 23 . This bending vibration pushes the air to vibrate, thereby producing sound. According to different signals (eg, signals of different frequencies), the piezoelectric sheet 23 can work in different vibration modes. The vibration mode refers to the vibration characteristics of the structure, with the natural frequency as the main feature. The natural frequency is related to the size and shape of the piezoelectric sheet 23, wherein the larger the size, the lower the natural frequency. The vibration mode also includes other characteristics, which may be the mode shape corresponding to the natural frequency. The mode shape is the form of vibration, which can include the location where the bending vibration occurs, the direction of the bending vibration, the vibration displacement of the bending vibration (in the order of microns, for example, between tens of microns and two or three hundred microns), and the like.

Different vibration modes, natural frequencies and mode shapes can be different. For example, the piezoelectric sheet 23 may have a first-order mode, a second-order mode, a third-order mode, etc. (other-order vibration modes other than the first-order mode may be collectively referred to as higher-order modes), wherein the natural frequency of the first-order mode is the smallest , for example, can be 500Hz-3000Hz. In the embodiments of the present application, the region of bending vibration may be referred to as a vibration region. The center of the vibration area may be the position where the maximum vibration displacement occurs in the vibration area, or may be an area within a certain range around the maximum vibration displacement (the range is determined as required). The vibration displacement in the vibration region of the first-order mode is larger.

FIGS. 9 and 10 show the bending vibration of the piezoelectric sheet 23 in the first-order mode. In order to clearly illustrate the vibration area, only a part of the piezoelectric sheet 23 is cut out in FIGS. 9 and 10 . 9 and 10, in the first-order mode, the vibration area 23a of the piezoelectric sheet 23 can be approximately a circular area with the geometric center 23c of the piezoelectric sheet 23 as the center of the circle, and the geometric center 23c is basically the vibration area. Center of 23a. FIG. 10 is a schematic diagram illustrating the bending vibration of the vibration region 23 a in one direction (eg, the upper side in the view of FIG. 10 ). As shown in FIG. 10 , the cross-section of the vibration region 23a may have a contour shape that approximates an ellipsoid or a water drop. The vibration displacement (distance from the equilibrium position) of each position in the vibration area 23a can be different, for example, the vibration displacement L0 is the largest at the geometric center 23c, and the vibration displacement L1 is smaller at a position slightly farther from the geometric center 23c, and the distance from the geometric center 23c is the largest. The vibration displacement L2 is smaller at a position farther from the center 23c. The vibration displacement L0 is also the maximum vibration displacement of the piezoelectric sheet 23 in all vibration modes.

In the high-order mode, the piezoelectric sheet 23 may have one or more vibration regions, and the vibration directions of each vibration region may not be exactly the same at the same time. For example, in the second-order mode, the piezoelectric sheet 23 may have two vibration regions, and the vibration directions of the two vibration regions may be opposite at the same time. Or in the third-order mode, the piezoelectric sheet 23 can have four vibration regions, two vibration regions can have the same vibration direction, and the other two vibration regions can have the same vibration direction, and the latter vibration direction is the same as the previous one. The direction can be reversed. As mentioned above, the maximum vibration displacement in other vibration modes is smaller than the vibration displacement L0 in the first-order mode.

The transmission part 24 can be approximately rod-shaped, column-shaped, block-shaped, etc. For example, the transmission part 24 shown in FIG. 8 is a square-shaped. As shown in FIG. 11 , one end of the transmission portion 24 (hereinafter referred to as the linkage end 242 ) is fixedly connected to the vibration region 23 a. The linkage end 242 overlaps with the vibration area 23a, that is, the projection of the linkage end 242 in the thickness direction of the piezoelectric sheet 23 may partially or completely fall within the vibration area 23a (referring to the vibration area 23a when the piezoelectric sheet 23 is not vibrating). . The linkage end 242 may be located near the center of the vibration area 23a (ie, the geometric center 23c of the piezoelectric sheet 23 ), for example, the geometric center of the linkage end 242 may substantially coincide with the center of the circle.

In other embodiments, the linkage end 242 can be connected to any vibration region of the piezoelectric sheet 23 in the high-order mode, and the orthographic projection of the linkage end 242 on the surface of the piezoelectric sheet 23 facing the hard vibration plate 21 is consistent with the vibration region. The centers at least partially overlap.

11 and FIG. 8 , the end of the transmission portion 24 opposite to the linkage end 242 may be referred to as the transmission end 241 , and the transmission end 241 is fixedly connected to the rigid vibration plate 21 . Therefore, when the vibration area 23a vibrates, the linkage end 242 will vibrate, and the linkage end 242 in turn causes the transmission end 241 to vibrate, and the transmission end 241 transmits the vibration to the rigid vibration plate 21, so that the rigid vibration plate 21 vibrates.

In the first embodiment, the transmission part 24 may be an integral part independent of the piezoelectric sheet 23 and the hard vibration plate 21, and the transmission part 24 may be assembled between the piezoelectric sheet 23 and the hard vibration plate 21, and connected to the pressure plate 23 and the hard vibration plate 21 respectively. The electric sheet 23 and the rigid vibration plate 21 are connected. Such a design can realize the modular manufacture of the piezoelectric electroacoustic device 20, which is convenient for debugging and maintenance. In other embodiments, the transmission part 24 may be integrated with the hard vibration plate 21 or the piezoelectric sheet 23 . For example, the transmission part 24 can be integrated with the hard vibration plate 21. The transmission part 24 can be a protrusion protruding from the surface of the hard vibration plate 21. The protrusion can be integrally formed with the hard vibration plate 21. The top end of the protrusion (ie, the linkage end 242 ) is connected with the piezoelectric sheet 23 through assembly. The integrated design can reduce assembly difficulty and improve the reliability of the piezoelectric electroacoustic device 20 .

In the first embodiment, the material of the transmission part 24 includes but is not limited to metal, non-metal, and composite material. There may be only one transmission part 24 . In other embodiments, there may be at least two transmission parts 24, and each transmission part 24 may be located in the vibration region 23a (for the first-order mode); or each transmission part 24 may be located in a different vibration region (for the high-order mode), and At the same time, each transmission portion 24 has substantially the same vibration direction.

As shown in FIG. 6 , the rigid vibration plate 21 may be in the shape of a flat plate, such as a square plate. The rigid vibration plate 21 can have a relatively large modulus and is not easily deformed. The modulus of the rigid vibration plate 21 may be greater than or equal to 1 GPa, such as 5 GPa, 20 GPa or 30 GPa. The thickness of the rigid vibration plate 21 may be, for example, 0.2 mm to 1 mm.

The material of the rigid vibration plate 21 may be, for example, a composite material composed of polymethacrylimide (PMI) and aluminum (or aluminum alloy), a composite material composed of PMI and carbon fiber, and a composite material composed of PMI and glass fiber. Material. Wherein, the PMI in the composite material can be sandwiched between two layers of aluminum or (or two layers of aluminum alloy), or between two layers of carbon fibers, or between two layers of glass fibers. Alternatively, the material of the hard vibration plate 21 can be, for example, a composite material composed of balsa wood and aluminum (or aluminum alloy), and the balsa wood in the composite material can be sandwiched between two layers of aluminum (or two layers of aluminum alloy). Alternatively, the material of the rigid vibration plate 21 may be, for example, foamed aluminum or foamed aluminum alloy. The rigid vibration plate 21 made of the above materials is lighter and more rigid, so that the rigid vibration plate 21 can have sufficient structural strength and good vibration performance. Of course, the material and internal structure of the hard vibration plate 21 are not limited to those described above.

As shown in FIG. 7 , the rigid vibration plate 21 and the piezoelectric sheet 23 are separated from each other by the transmission portion 24 . The rigid vibrating plate 21 and the piezoelectric sheet 23 are spaced apart and arranged in layers, and "spaced lamination" means that the two are spaced apart, and the two may be substantially parallel. Along the thickness direction of the rigid vibration plate 21, the rigid vibration plate 21 and the piezoelectric sheet 23 may be substantially overlapped, and the two have substantially the same area. Both the area of the hard vibration plate 21 and the area of the piezoelectric sheet 23 refer to the area of the surface perpendicular to the thickness direction of the respective surfaces. The same below.

In other embodiments, on the premise that the area of the hard vibration plate 21 is larger than the area of the vibration region 23a, the hard vibration plate 21 and the piezoelectric sheet 23 may be dislocated, and the relationship between the areas of the two may not be limited. The area of the mass vibration plate 21 may be greater than or equal to the area of the piezoelectric sheet 23 .

In the first embodiment, the vibration area 23a is a local area of the piezoelectric sheet 23, and the area of the hard vibration plate 21 is larger than the area of the vibration area 23a. For example, the area of the hard vibration plate 21 may be approximately twice the area of the vibration region 23a. The hard vibration plate 21 can completely cover the vibration area 23a. "Complete coverage" may include the following meanings: as shown in FIG. 12 , the surface 21a of the rigid vibration plate 21 facing the piezoelectric sheet 23 is used as the projection surface, and the orthographic projection of the vibration area 23a on the projection surface all falls on the projection surface , all boundaries of this orthographic surface are separated from the corresponding boundaries of this projection surface. Alternatively, a part of the boundary of the orthographic projection of the vibration area 23a on the projection surface coincides with the corresponding boundary of the projection surface, and another part of the boundary falls inside the projection surface, and the other part of the boundary is separated from the corresponding boundary of the projection surface.

In other embodiments, as shown in FIG. 12 , when the linkage end 242 is connected to other vibration regions (hereinafter referred to as other vibration regions) of the piezoelectric sheet 23 in the high-order mode, the rigid vibration plate 21 can completely cover the vibration region , the meaning of "complete coverage" here is the same as above.

Alternatively, in other embodiments, on the premise that the area of the hard vibration plate 21 is larger than the area of the vibration area 23a or the area of other vibration areas, the hard vibration plate 21 can be dislocated from the vibration area 23a or other vibration areas, and the dislocation is It means that the two partially overlap in the thickness direction of the hard vibration plate 21, that is, a part of the vibration area 23a or a part of other vibration areas overlaps with the hard vibration plate 21, or the whole or other vibration areas of the vibration area 23a. All of them overlap with the hard vibration plate 21 .

In the embodiment of the present application, the piezoelectric sheet 23 is used as a driving member, and the transmission portion 24 can transmit vibration, thereby driving the hard vibration plate 21 to vibrate (the hard vibration plate 21 is equivalent to a piston, and its vibration is equivalent to the reciprocating movement of the piston). When the hard vibration plate 21 vibrates, it can push the air to vibrate. Since the area of the hard vibration plate 21 is large, and the areas of the vibration area 23a and other vibration areas are small, the vibration of the small area of the piezoelectric sheet 23 can drive the vibration of the large area of the hard vibration plate 21 , thereby pushing more air to vibrate. That is, the design of the embodiment of the present application makes the effective vibration area of the piezoelectric electro-acoustic device 20 larger (for example, the effective vibration area of the piezoelectric electro-acoustic device 20 can be substantially twice that of a conventional piezoelectric electro-acoustic device) , thereby increasing the amount of air that the piezoelectric electroacoustic device 20 can push.

In addition, the larger the vibration displacement of the hard vibration plate 21 is, the larger the amount of air that the hard vibration plate 21 can push. When the linkage end 242 is substantially located at the center of the vibration area 23a, the vibration displacement of the rigid vibration plate 21 is larger, so the amount of air that the rigid vibration plate 21 can push is also larger.

As shown in FIG. 7 and FIG. 8 , the gasket 22 may be a frame body, such as a frame, which surrounds the circumference. The washer 22 connects the rigid vibration plate 21 and the piezoelectric sheet 23 . The gasket 22 may be located at the edges of the rigid vibration plate 21 and the piezoelectric sheet 23, for example, substantially aligned with the edges of the rigid vibration plate 21 and the piezoelectric sheet 23. The washer 22, the hard vibration plate 21 and the piezoelectric sheet 23 form a closed cavity 20a (see FIG. 7).

The gasket 22 can be made of elastic materials, such as ethylene vinyl acetate copolymer (EVA), rubber, silicone, foam (which can be glued), and the like. These elastic materials are elastic and relatively soft. The gasket 22 can be relatively thin, eg 0.2mm-1mm thick.

7 and 8, the gasket 22 can play the role of supporting and fixing the rigid vibration plate 21, and can also seal the gap between the rigid vibration plate 21 and the piezoelectric sheet 23 to avoid air leakage (if there is any). If the air leaks, the sound wave cannot be conducted according to the design requirements, which will affect the sound). Due to the elastic properties of the washer 22, the washer 22 can also provide elastic restoring force to the hard vibration plate 21, and ensure that the peripheral edge of the hard vibration plate 21 has sufficient degrees of freedom, so that the hard vibration plate 21 can vibrate sufficiently and reliably.

13 and 14 describe the assembly relationship of the middle frame 12, the piezoelectric electroacoustic device 20 and the back cover 13 in cross-sectional views, wherein FIG. 13 is a schematic view of the AA cross-sectional structure of the electronic device in FIG. A schematic diagram of a partially enlarged structure at E in FIG. 13 . As shown in FIG. 14 , the piezoelectric electro-acoustic device 20 may be installed between the first cover part 121 of the middle frame 12 and the second cover part 131 of the rear cover 13 .

The rigid vibration plate 21 of the piezoelectric electro-acoustic device 20 can be connected to the first cover portion 121 . For example, FIG. 14 shows the connection relationship between the rigid vibration plate 21 and the second wall 121 b of the first cover portion 121 . . In fact, the hard vibration plate 21 may be connected to the first wall 121a, the second wall 121b and the third wall 121c of the first cover part 121, and the first wall 121a, the second wall 121b and the third wall 121c may all be connected Connected to the edge of the hard vibration plate 21 . The connection includes, but is not limited to, bonding, welding, clipping, and the like. The hard vibration plate 21 can abut against the side surface 12e of the middle frame 12 . The rigid vibration plate 21 is spaced apart from the bottom surface 12d of the mounting groove 12c. The space may serve as a front cavity of the piezoelectric electroacoustic device 20 , and thus the first cover portion 121 may serve as a front case of the piezoelectric electroacoustic device 20 .

The piezoelectric sheet 23 of the piezoelectric electro-acoustic device 20 may be connected to the second cover portion 131 . For example, FIG. 14 shows the connection relationship between the piezoelectric sheet 23 and one of the walls 131 a of the second cover portion 131 . Actually, the edge of the piezoelectric sheet 23 may be connected with all the four walls 131 a of the second cover part 131 . The connection includes, but is not limited to, bonding, welding, clipping, and the like. The electric sheet 23 can abut against the side surface 12e of the middle frame 12 . The piezoelectric sheet 23 is spaced from the inner surface 13 a of the rear cover 13 . The space can serve as a back cavity of the piezoelectric electroacoustic device 20 , and thus the second cover portion 131 can serve as a back shell of the piezoelectric electroacoustic device 20 .

In the embodiment of the present application, the piezoelectric electroacoustic device 20 may be staggered out of the sound hole 12b. For example, as shown in FIG. 14 , the sound outlet hole 12b may be located between the hard vibration plate 21 and the bottom surface 12d. Alternatively, in the vertical direction in the viewing angle of FIG. 14 , the upper surface of the hard vibration plate 21 may be substantially flush with the lower hole wall of the sound outlet hole 12b. The above design enables the sound waves generated by the vibration of the rigid vibration plate 21 to be transmitted to the outside of the electronic device 10 through the sound outlet hole 12b. When the human ear receives this sound wave, it forms hearing.

In the first embodiment, by designing the vibration structure of the piezoelectric sheet 23-transmission part 24-hard vibrating plate 21, the original small-area vibration of the piezoelectric sheet 23 can be amplified into the large-area vibration of the hard vibrating plate 21, so that the pressure The effective vibration area of the electroacoustic device 20 is larger than that of a conventional piezoelectric electroacoustic device. After the effective vibration area is increased, the amount of air that the piezoelectric electro-acoustic device 20 can push also increases (especially when the linkage end 242 is basically located at the center of the vibration area 23a), which makes the piezoelectric electro-acoustic device 20 have a higher performance. The low frequency sensitivity and better low frequency performance, so that the output sound contains more bass part.

In addition, the high-frequency sensitivity of conventional piezoelectric electroacoustic devices is too high but the low-frequency sensitivity is low, resulting in an unbalanced frequency response in the three frequency bands of high frequency, intermediate frequency and low frequency. Since the low-frequency sensitivity of the piezoelectric electro-acoustic device 20 is improved, the problem of unbalanced frequency response can be reduced or overcome, so that the frequency responses of the high-frequency, mid-frequency and low-frequency three frequency bands can be well balanced, so that the piezoelectric electro-acoustic device 20 can The acoustic device 20 has better overall sound quality performance.

Moreover, by using the structures on the middle frame 12 and the rear cover 13 as the front and rear shells of the piezoelectric electroacoustic device 20 , the design and manufacture of the piezoelectric electroacoustic device 20 can be simplified and the device manufacturing cost can be reduced. In addition, since the piezoelectric electro-acoustic device 20 does not include a front case and a rear case, the thickness is small, which is beneficial to realize the thinning of the electronic device 10 .

15 and 16 show the structure of the piezoelectric electro-acoustic device 20 in the second embodiment, wherein FIG. 16 is a schematic cross-sectional structure diagram of the piezoelectric electro-acoustic device 20 in the second embodiment, and its cross section is the same as that in FIG. 6 . The cross-section DD of , so DD is still used as the cross-section mark in Figure 16. The same below.

As shown in FIGS. 15 and 16 , in the second embodiment, the piezoelectric electroacoustic device 20 may further include an isolation film 25 . The isolation film 25 may have a substantially flat sheet shape, such as a square sheet shape. The isolation film 25 can be made of elastic materials, including but not limited to polyurethane (PU), thermoplastic polyurethanes (TPU), rubber, silicone, polyethylene terephthalate (PET), polyether Imide (polyetherimide, PEI) and the like. The above elastic material has elasticity and is also relatively soft.

As shown in FIGS. 15 and 16 , the isolation film 25 and the piezoelectric sheet 23 are respectively located on opposite sides of the gasket 22 , and the periphery of the isolation film 25 is connected (eg, glued) to the gasket 22 . The isolation film 25, the gasket 22 and the piezoelectric sheet 23 enclose a closed cavity 20b. The difference between the second embodiment and the first embodiment is that the rigid vibration plate 21 in the second embodiment is not connected to the surface of the gasket 22 facing away from the piezoelectric sheet 23, but is connected to the surface of the isolation film 25 facing the piezoelectric sheet 23 (for example, bonding). The hard vibration plate 21 is located in the cavity 20b, and the boundary of each segment of the hard vibration plate 21 can be spaced from the corresponding boundary of the washer 22, that is, the periphery of the hard vibration plate 21 shrinks within the periphery of the isolation film 25. The distances from the boundary of each segment of the rigid vibration plate 21 to the corresponding boundary of the isolation film 25 may be substantially the same. The transmission part 24 is also located in the cavity 20b.

In other embodiments, on the premise that the hard vibration plate 21 is kept in the cavity 20b, the position of the hard vibration plate 21 relative to the isolation film 25 can be designed as required.

The isolation film 25 is driven by the hard vibration plate 21 and follows the vibration of the hard vibration plate 21 to generate reciprocating bending deformation, that is, vibration.

FIG. 17 is a partial cross-sectional schematic diagram showing the assembly position of the piezoelectric electroacoustic device 20 in the electronic device 10 in the second embodiment. The expression of FIG. 17 refers to FIG. 14 , and the same partial enlarged position mark E as in FIG. 14 is still used in FIG. 17 . This means that the partially enlarged position of FIG. 17 is the same as that of FIG. 14 , and the difference is that the piezoelectric electroacoustic device 20 in FIG. 17 has a different structure from the piezoelectric electroacoustic device 20 in FIG. 14 .

As shown in FIG. 17 , after the isolation film 25 is designed, the isolation film 25 replaces the position of the rigid vibration plate 21 in the first embodiment. That is, the isolation film 25 can be connected with the first cover part 121 , for example, the connection relationship between the isolation film 25 and the second wall 121 b of the first cover part 121 is shown in FIG. 17 . In practice, the isolation membrane 25 may be connected to all of the first wall 121a, the second wall 121b and the third wall 121c of the first cover part 121, and the first wall 121a, the second wall 121b and the third wall 121c may all be connected to The edge of the isolation film 25 . The connection includes, but is not limited to, bonding, welding, clipping, and the like. The release film 25 can abut against the side surface 12e of the middle frame 12 . The isolation film 25 is spaced from the bottom surface 12d of the mounting groove 12c, and the space can serve as a front cavity of the piezoelectric electroacoustic device 20. As shown in FIG. The isolation membrane 25 can serve as a boundary between the front cavity and the rear cavity.

In the second embodiment, the sound outlet hole 12b may be located between the isolation membrane 25 and the bottom surface 12d. Alternatively, in the vertical direction in the viewing angle of FIG. 17 , the upper surface of the isolation film 25 may be substantially flush with the lower side hole wall of the sound outlet hole 12b. The above design enables the sound waves generated by the vibration of the isolation membrane 25 to be transmitted to the outside of the electronic device 10 through the sound outlet hole 12b.

In the second embodiment, the isolation film 25 made of elastic material has a good sealing effect, which can well isolate the front cavity and the rear cavity of the piezoelectric electroacoustic device 20, and block the air flow between the front cavity and the rear cavity. , so as to avoid the phenomenon of acoustic short circuit. The isolation film 25 can also play the role of suspending the hard vibration plate 21 and provide elastic restoring force to the hard vibration plate 21 to ensure that the hard vibration plate 21 can vibrate stably.

In addition, the use of the isolation film 25 beyond the boundary of the rigid vibration plate 21 realizes the pulling of the rigid vibration plate 21, and this structure is relatively easy to manufacture. In contrast, in the first embodiment, the washer 22 is used to pull the hard vibration plate 21, which requires the washer 22 to have higher elasticity. However, under the circumstance that the thickness of the gasket 22 is limited, the elasticity of the gasket 22 is required to be good, which will bring difficulties to the material selection of the gasket 22 and affect the manufacturability. Therefore, the solution of the second embodiment has high manufacturability and is easy to implement.

As shown in FIG. 18 , based on the solution of the first embodiment, the isolation membrane 25 in the third embodiment may include a first vibrating part 251 , a first folding ring 252 and a first connecting part 253 , and the first folding ring 252 is connected to the first vibration part 251 . The vibrating portion 251 and the first connecting portion 253 , the first connecting portion 253 surrounds the outer circumference of the first folding ring 252 , and the first folding ring 252 surrounds the outer circumference of the first vibrating portion 251 .

As shown in FIG. 18 , the first vibrating portion 251 may be in the shape of a flat sheet, such as a square sheet. The first vibrating portion 251 is connected to the hard vibrating plate 21, and the two are substantially parallel. The boundary of the first vibration part 251 may be substantially aligned with the boundary of the hard vibration plate 21 , that is, the first vibration part 251 and the hard vibration plate 21 are substantially overlapped. The first fold ring 252 is bent and arched in the direction away from the piezoelectric sheet 23 , and the first fold ring 252 may be located between the hard vibration plate 21 and the washer 22 . The first connection part 253 is connected with the gasket 22 , and the first connection part 253 may substantially overlap with the gasket 22 .

In the third embodiment, when the rigid vibration plate 21 vibrates, the first folding ring 252 can be deformed accordingly. The arched shape of the first folding ring 252 reduces the vibration resistance of the hard vibration plate 21, so that the hard vibration plate 21 can basically maintain a flat state without bending and deformation during the vibration process, that is, the hard vibration plate 21 can Keep the piston moving, which is beneficial to ensure the acoustic effect of the piezoelectric electroacoustic device 20 . In addition, the first folding ring 252 can also suspend the rigid vibration plate 21 and provide elastic restoring force, so that it can be maintained at a set position.

FIG. 19 can show the assembly relationship between the isolation film 25 and the middle frame 12 in the third embodiment. As shown in FIG. 19 , the first folding ring 252 is staggered from the first cover portion 121 on the middle frame 12 , and the first connecting portion 253 is connected to the first cover portion 121 . Therefore, the first folding ring 252 will not interfere with the first cover portion 121 .

As shown in FIG. 20 , in the fourth embodiment, the difference from the third embodiment is that the first folding ring 252 can be bent and arched toward the direction close to the piezoelectric sheet 23 . This design enables the first fold ring 252 to be accommodated in the space of the piezoelectric electroacoustic device 20 itself, so that the piezoelectric electroacoustic device 20 of the fourth embodiment is thinner.

As shown in FIGS. 21 and 22 , in the fifth embodiment, based on the solution of the first embodiment, the piezoelectric electroacoustic device 20 may further include a diaphragm 26 . The diaphragm 26 may be substantially in the shape of a flat diaphragm, such as a square diaphragm. The diaphragm 26 can be made of a hard film material, such as a metal film material such as magnesium aluminum alloy and copper, or a PET film material, a carbon fiber film material, and the like.

As shown in FIGS. 21 and 22 , the diaphragm 26 and the hard vibration plate 21 are located on opposite sides of the washer 22 respectively, and the periphery of the diaphragm 26 is connected (eg, glued) to the washer 22 . The diaphragm 26, the washer 22 and the hard vibration plate 21 can enclose a closed cavity 20c. The difference between the fifth embodiment and the first embodiment is that in the fifth embodiment, the transmission part 24 is connected between the hard vibration plate 21 and the vibration film 26 . The piezoelectric sheet 23 is not connected to the washer 22 , but is connected (eg, glued) to the surface of the diaphragm 26 facing away from the washer 22 . The boundaries of each segment of the piezoelectric sheet 23 can be indented within the corresponding boundary of the diaphragm 26 , that is, the orthographic projection of the piezoelectric sheet 23 on the diaphragm 26 can completely fall within the boundary of the diaphragm 26 . The distances from the boundary of each segment of the piezoelectric sheet 23 to the corresponding boundary of the diaphragm 26 may be substantially the same. The transmission part 24 is located in the cavity 20c.

In other embodiments, on the premise that all the orthographic projections of the piezoelectric sheet 23 on the vibrating film 26 fall on the vibrating film 26, the position of the piezoelectric sheet 23 relative to the vibrating film 26 can be designed as required.

FIG. 23 is a partial cross-sectional schematic diagram showing the assembly position of the piezoelectric electroacoustic device 20 in the electronic device 10 in the fifth embodiment. The expression of FIG. 23 refers to FIG. 14 , and the same partial enlarged position mark E as in FIG. 14 is still used in FIG. 23 . This means that the partially enlarged position of FIG. 23 is the same as that of FIG. 14 , and the difference is that the piezoelectric electroacoustic device 20 in FIG. 23 has a different structure from the piezoelectric electroacoustic device 20 in FIG. 14 .

As shown in FIG. 23 , after the vibrating membrane 26 is designed, the vibrating membrane 26 replaces the position of the piezoelectric sheet 23 in the first embodiment. That is, the diaphragm 26 can be connected to the second cover part 131 , for example, FIG. 23 shows the connection relationship between the diaphragm 26 and one of the walls 131 a of the second cover part 131 . Actually, the diaphragm 26 may be connected with all the walls 131a of the second cover part 131 , and all the walls 131a may be connected at the edge of the diaphragm 26 . The connection includes, but is not limited to, bonding. The diaphragm 26 can abut against the side surface 12e of the middle frame 12 .

In the fifth embodiment, the edge of the piezoelectric sheet 23 is not fixed by the second cover portion 131 , and the vibration resistance of the piezoelectric sheet 23 is reduced, so that the vibration displacement of the piezoelectric sheet 23 can be increased, thereby making the rigid vibration plate 21 . Vibration displacement increases. This is beneficial to increase the amount of air that the piezoelectric electro-acoustic device 20 can push, thereby further enhancing the low-frequency performance and overall sound quality performance of the piezoelectric electro-acoustic device 20 .

The piezoelectric electroacoustic device 20 in the fifth embodiment does not contain the isolation film 25, which is only an example. In fact, disposing the isolation film 25 and disposing the vibrating film 26 are independent of each other and do not affect each other. The piezoelectric electro-acoustic device 20 may include both the isolation film 25 and the vibrating film 26 (which will be described below), or only one of the two. either.

As shown in FIG. 24 , in the sixth embodiment, the difference from the fifth embodiment is that the piezoelectric sheet 23 can be located between the vibrating film 26 and the hard vibration plate 21 , and the piezoelectric sheet 23 and the vibrating film 26 vibrate toward the hard vibration. The surfaces of the plates 21 are connected, for example, the thickness directions of the two are basically consistent and fit. The transmission part 24 connects the rigid vibration plate 21 and the piezoelectric sheet 23 . The design of the sixth embodiment not only has the advantages of the design of the fifth embodiment, but also can use the inner space of the piezoelectric electroacoustic device 20 to accommodate the piezoelectric sheet 23 without additionally occupying the structural space outside the piezoelectric electroacoustic device 20, so that the The piezoelectric electroacoustic device 20 is thin.

As shown in FIG. 25 , in the seventh embodiment, based on the solution of the sixth embodiment, the piezoelectric electro-acoustic device 20 may include two piezoelectric sheets 23 (which may be referred to as a first piezoelectric sheet and a second piezoelectric sheet respectively). ), the first piezoelectric sheet and the second piezoelectric sheet are respectively connected to opposite sides of the diaphragm 26 . Wherein, the first piezoelectric sheet may be located between the hard vibration plate 21 and the vibrating film 26 , and the first piezoelectric sheet and the vibrating film 26 may keep the thickness direction substantially consistent and adhere to each other. The shape and area of the first piezoelectric sheet and the second piezoelectric sheet may be substantially the same. The second piezoelectric sheet may substantially overlap with the first piezoelectric sheet in the thickness direction of the diaphragm 26 . In other embodiments, the shapes, areas and relative positions of the first piezoelectric sheet and the second piezoelectric sheet can be designed as required, and are not limited to the above.

As shown in FIG. 25 , the transmission part 24 connects the rigid vibration plate 21 and the first piezoelectric sheet. Both the first piezoelectric sheet and the second piezoelectric sheet can drive the transmission portion 24 to vibrate. The use of the first piezoelectric sheet and the second piezoelectric sheet can provide a larger driving force to the transmission part 24, so that the vibration displacement of the rigid vibration plate 21 is larger, which is conducive to pushing more air to vibrate, thereby improving the piezoelectric Low frequency performance and overall sound quality performance of the electroacoustic device 20 . Meanwhile, the degrees of freedom of movement of the first piezoelectric sheet and the second piezoelectric sheet in the seventh embodiment are relatively large, and the entire first piezoelectric sheet and the entire second piezoelectric sheet can vibrate. This design enables the piezoelectric electroacoustic device 20 in the seventh embodiment to have a larger effective vibration area, so that the low frequency performance and overall sound quality of the piezoelectric electroacoustic device 20 are better.

As shown in FIG. 26 , in Embodiment 8, based on the solution of Embodiment 5 above, the diaphragm 26 may include a second connecting portion 261 , a second folding ring 262 and a second vibrating portion 263 . The second folding ring 262 connects the second connecting portion 261 and the second vibrating portion 263 , the second connecting portion 261 surrounds the outer periphery of the second folding ring 262 , and the second folding ring 262 surrounds the outer periphery of the second vibrating portion 263 .

The second vibrating portion 263 may be in the shape of a flat sheet, such as a square sheet. The boundary of the second vibrating portion 263 may exceed the boundary of the piezoelectric sheet 23 , or may be substantially flush with the boundary of the piezoelectric sheet 23 . The second vibration part 263 is connected to the transmission part 24 . The second fold ring 262 may be spaced apart from the piezoelectric sheet 23 , and may be bent and arched in a direction away from the hard vibration plate 21 . The second connection part 261 is connected with the gasket 22 , and the second connection part 261 may substantially overlap with the gasket 22 .

In the eighth embodiment, when the piezoelectric sheet 23 vibrates, the second folding ring 262 can be deformed accordingly. The arched shape of the second folding ring 262 reduces the vibration resistance of the piezoelectric sheet 23, so that the vibration displacement of the piezoelectric sheet 23 can be increased, thereby increasing the vibration displacement of the hard vibration plate 21, which is beneficial to improve the piezoelectric The amount of air that the electroacoustic device 20 can push further enhances the low frequency performance and overall sound quality performance of the piezoelectric electroacoustic device 20 . In addition, the second folding ring 262 can also suspend the piezoelectric sheet 23 and provide elastic restoring force, so that it can be maintained at the set position.

In other embodiments, different from the eighth embodiment, the second folding ring 262 can be bent and arched toward the direction close to the hard vibration plate 21 . That is, the difference between the two designs is that the bending and arching directions of the second folding ring 262 are opposite.

As shown in FIGS. 27 and 28 , in the ninth embodiment, based on the solution of the fifth embodiment, a plurality of through holes 26 a may be opened on the diaphragm 26 . The number of the through holes 26a is not limited, for example, it can be twelve. Each through hole 26a may be located at the edge of the diaphragm 26, and each edge of the diaphragm 26 has through holes 26a distributed. For example, in FIG. 27 , there are through holes 26a distributed on the four sides of the diaphragm 26, and all the through holes 26a can approximately form a closed annular array. The shape of each through hole 26a is not limited, for example, it may be a round hole or a square hole.

As shown in FIG. 27 and FIG. 28 , each through hole 26 a can connect the rear cavity of the piezoelectric electro-acoustic device 20 with the cavity between the diaphragm 26 and the hard vibration plate 21 . That is, each through hole 26a can connect the side of the diaphragm 26 away from the cavity 20c to communicate with the cavity 20c. Each through hole 26a may be completely staggered from the piezoelectric sheet 23 , the second cover part 131 and the gasket 22 ; A partial overlap. For example, the through hole 26a in FIG. 28 can be enlarged or shifted to the right, so that the through hole 26a and the piezoelectric sheet 23 are partially overlapped, and at this time, the piezoelectric sheet 23 partially covers the through hole 26a.

In the ninth embodiment, by opening a through hole 26a on the diaphragm 26, the through hole 26a can connect the rear cavity of the piezoelectric electro-acoustic device 20 with the cavity 20c between the diaphragm 26 and the hard vibration plate 21, This is equivalent to enlarging the back cavity of the piezoelectric electroacoustic device 20 , thereby increasing the low frequency resonance of the piezoelectric electroacoustic device 20 and improving the low frequency performance of the piezoelectric electroacoustic device 20 .

As shown in FIG. 29 , in the tenth embodiment, different from the ninth embodiment, the number of the through holes 26a may be less, for example, four. All the through holes 26a may be distributed only at the corners of the diaphragm 26, such as four corners. The design of the tenth embodiment can ensure the structural strength of the diaphragm 26 .

In other embodiments, the number of the through holes 26a can be designed as required, as long as the communication function can be ensured. For example, the through hole 26a may be one, two, three, or the like.

The diaphragm 26 in the ninth and tenth embodiments does not include the second folding ring 262, which is only an example. Actually, when the diaphragm 26 includes the second folding ring 262 , a through hole 262 a may be formed on the second folding ring 262 .

As shown in FIGS. 30 and 31 , in the eleventh embodiment, different from the second or fifth embodiment, the piezoelectric electro-acoustic device 20 may include an isolation film 25 and a vibrating film 26 at the same time. The isolation film 25 , the gasket 22 and the vibrating film 26 enclose a closed cavity 20d, and the hard vibration plate 21 and the transmission part 24 are both located in the cavity 20d. The transmission part 24 is connected to the rigid vibration plate 21 and the vibration film 26 , and the piezoelectric sheet 23 may be located on the side of the vibration film 26 away from the transmission part 24 . In the eleventh embodiment, the structures, dimensions, materials, and positional relationships and connection relationships with other components of the isolation film 25 and the diaphragm 26 can be the same as above, and will not be repeated here.

In the piezoelectric electro-acoustic device 20 of the eleventh embodiment, since the entire rigid vibration plate 21 and the entire piezoelectric sheet 23 can vibrate, the effective vibration area of the piezoelectric electro-acoustic device 20 is larger, and the low-frequency performance and overall Better sound quality. Moreover, since the isolation film 25 is used, the phenomenon of acoustic short circuit is less likely to occur.

In other embodiments, based on the solution in Embodiment 11, the piezoelectric sheet 23 and the vibrating membrane 26 may exchange positions (as shown in FIG. 24 ); the opposite sides of the vibrating membrane 26 may be connected to the piezoelectric sheet 23 (as shown in FIG. 24 ). 25); the diaphragm 26 may include a second ring 262 (as shown in FIG. 26 ); a through hole 26a may be opened on the diaphragm 26 (as shown in FIGS. 27 and 29 ); the isolation diaphragm 25 may include a first Folding ring 252 (shown in Figures 18 and 20). In the embodiments of the present application, the above designs can be freely combined as required.

The piezoelectric electroacoustic devices 20 in the above embodiments all use the middle frame 12 of the electronic device 10 to form the front cavity, and use the rear cover 13 to form the rear cavity. The difference is that in the twelfth embodiment to be described below, the piezoelectric electro-acoustic device 30 itself has a rear shell 31, and the rear cavity of the piezoelectric electro-acoustic device 30 is enclosed by the rear shell 31. It will be described in detail below.

Referring to FIGS. 32 and 33 , in the twelfth embodiment, different from the above-mentioned embodiments, there is no second cover portion 131 on the rear cover 13 of the electronic device 10 , and the rear cover 13 does not participate in forming the rear cavity.

33, 34 and 35 show the schematic structure of the piezoelectric electroacoustic device 30 of the twelfth embodiment. As shown in FIGS. 33-35 , the piezoelectric electro-acoustic device 30 may further include a rear case 31 . The piezoelectric electroacoustic device 30 can be considered as adding a rear case 31 to the piezoelectric electroacoustic device 20 in FIG. 30 . It should be understood that this is only an example, in fact, the rear case 31 can be assembled with the piezoelectric electro-acoustic device 20 of any of the above embodiments, and the piezoelectric electro-acoustic device 30 can be obtained.

As shown in FIG. 35 , the rear case 31 may be substantially in a slot-like structure, such as a square slot structure. The rear case 31 may include a bottom wall 311 and several side walls 312 (for example, four), each side wall 312 is protruding on the periphery of the bottom wall 311 , and all the side walls 312 are connected end to end to form a closed wall structure. The top end of each side wall 312 is connected (eg, glued) to the periphery of the diaphragm 26 , so that the rear case 31 and the diaphragm 26 enclose a rear cavity (the rear cavity will be shown in FIG. 36 ). In other embodiments, each side wall 312 of the rear shell 31 may enclose an open wall structure (similar to a C shape), and at this time, the rear cavity enclosed by the rear shell 31 and the diaphragm 26 is an open rear cavity.

FIG. 36 is a partial cross-sectional schematic diagram showing the assembled position of the piezoelectric electroacoustic device 30 in the electronic device 10 in the twelfth embodiment. The expression of FIG. 36 refers to FIG. 14 , and the same partial enlarged position mark E as in FIG. 14 is still used in FIG. 36 . This means that the partially enlarged position of FIG. 36 is the same as the partially enlarged position of FIG. 14 , and the difference is that the piezoelectric electroacoustic device 20 in FIG. 36 has a different structure from that in FIG. 14 .

As shown in FIG. 36 , the rear case 31 may be mounted on the inner surface 13a of the rear cover 13, and the bottom wall 311 of the rear case 31 is connected (eg, glued or welded) to the inner surface 13a. Other components of the piezoelectric electro-acoustic device 30, such as the isolation diaphragm 25, the hard vibration plate 21, the gasket 22, the transmission part 24, the diaphragm 26 and the piezoelectric sheet 23, can be assembled in the same relationship as in the eleventh embodiment (such as 30), which will not be repeated here.

The piezoelectric electro-acoustic device 30 of the twelfth embodiment has its own back shell 31. This piezoelectric electro-acoustic device 30 is relatively modular, and is easy to be assembled with the housing of the electronic device 10, and its operational reliability is not easily affected by assembly. . Of course, the low frequency performance and the overall sound quality performance of the piezoelectric electroacoustic device 30 are also better.

As shown in FIG. 37 , in the thirteenth embodiment, different from any of the above-mentioned embodiments, the middle frame 12 of the electronic device 10 does not have the first cover portion 121 , and the middle frame 12 does not participate in forming the front cavity.

38, 39 and 40 show the schematic structure of the piezoelectric electroacoustic device 40 of the thirteenth embodiment. As shown in FIGS. 38-40 , the piezoelectric electroacoustic device 40 may further include a front case 41 . The piezoelectric electroacoustic device 40 can be considered as adding a front case 41 to the piezoelectric electroacoustic device 20 of FIG. 30 . It should be understood that this is only an example, in fact, the front case 41 can be assembled with the piezoelectric electroacoustic device 20 of any of the above embodiments, and the piezoelectric electroacoustic device 40 can be obtained.

As shown in FIG. 40 and FIG. 41 , the front case 41 may include a bottom wall 411 and a plurality of side walls 412 (for example, three), each side wall 412 is protruded on the periphery of the bottom wall 411 , and all the side walls 412 are connected in sequence. It forms an open wall structure (similar to a C shape), in which one side of the bottom wall 411 does not have the side wall 41 .

As shown in FIG. 38 and FIG. 39 , the top end of the side wall 412 is connected (eg, glued) to the peripheral edge of the side of the isolation film 25 away from the gasket 22 , so the front shell 41 and the isolation film 25 enclose a front cavity (the front cavity will be shown in Figure 42). The front cavity has an outlet 40a for the sound waves in the front cavity to pass out.

FIG. 42 is a schematic partial cross-sectional view showing the assembled position of the piezoelectric electroacoustic device 40 in the electronic device 10 in the thirteenth embodiment. The expression of FIG. 42 refers to FIG. 14 , and in FIG. 42 the same partial enlarged position mark E as in FIG. 14 is still used. This means that the partially enlarged position of FIG. 42 is the same as that of FIG. 14 , and the difference is that the piezoelectric electroacoustic device 40 in FIG. 42 has a different structure from the piezoelectric electroacoustic device 20 in FIG. 14 .

As shown in FIG. 42 , the front case 41 can be installed on the bottom surface 12d of the middle frame 12, and the bottom wall 411 of the front case 41 is connected (eg, glued or welded) to the bottom surface 12d. The outlet 40a of the front cavity of the piezoelectric electro-acoustic device 20 may communicate with the sound outlet 12b, so that the sound waves in the front cavity can be propagated to the outside of the electronic device 10 through the outlet 40a and the sound outlet 12b. Other components of the piezoelectric electro-acoustic device 40, such as the isolation diaphragm 25, the hard vibration plate 21, the gasket 22, the transmission part 24, the diaphragm 26 and the piezoelectric sheet 23, can be assembled in the same relationship as in the eleventh embodiment (such as 30), which will not be repeated here.

The piezoelectric electro-acoustic device 40 of the thirteenth embodiment has its own front case 41. This piezoelectric electro-acoustic device 40 is relatively modular, easy to be assembled with the housing of the electronic device 10, and its operational reliability is not easily affected by assembly. . Of course, the low frequency performance and the overall sound quality performance of the piezoelectric electroacoustic device 40 are also better.

As shown in FIGS. 43 , 44 and 45 , the piezoelectric electroacoustic device 50 in the fourteenth embodiment includes both the front case 41 and the rear case 31 . It can be considered that the piezoelectric electroacoustic device 50 is based on the piezoelectric electroacoustic device 30 with the front case 41 added, or the piezoelectric electroacoustic device 40 with the rear case 31 added. In the piezoelectric electro-acoustic device 50, the assembly or assembly between the front case 41, the rear case 31 and other components such as the isolation diaphragm 25, the hard vibration plate 21, the gasket 22, the transmission part 24, the diaphragm 26 and the piezoelectric sheet 23 The positional relationship is the same as above, and will not be repeated here.

FIG. 46 is a schematic partial cross-sectional view showing the assembled position of the piezoelectric electroacoustic device 50 in the electronic device 10 in the fourteenth embodiment. The expression of Fig. 46 refers to Fig. 14, and in Fig. 46 the same partial enlarged position mark E as in Fig. 14 is still used. This means that the partially enlarged position of FIG. 46 is the same as that of FIG. 14 , and the difference is that the piezoelectric electroacoustic device 50 in FIG. 46 has a different structure from the piezoelectric electroacoustic device 20 in FIG. 14 .

As shown in FIG. 46 , in the fourteenth embodiment, the middle frame 12 of the electronic device does not have the first encapsulation portion 121 , the middle frame 12 does not participate in forming the front cavity, and the front shell 41 and the isolation film 25 enclose the front cavity. The rear cover 13 does not have the second encapsulation portion 131 , the rear cover 13 does not participate in forming the rear cavity, and the rear shell 31 and the diaphragm 26 enclose the rear cavity. The assembly relationship between the front shell 41 and the middle frame 12 and the assembly relationship between the rear shell 31 and the rear cover 13 are the same as those described above, and will not be repeated here.

The piezoelectric electroacoustic device 50 of the fourteenth embodiment has its own front case 41 and a rear case 31. The piezoelectric electroacoustic device 50 has a compact structure and a high degree of modularity, and is easy to be assembled with the housing of the electronic device 10. And the working reliability is not easily affected by the assembly. Of course, the low frequency performance and the overall sound quality performance of the piezoelectric electroacoustic device 50 are also better.

For each piezoelectric electro-acoustic device in the above embodiments, the transmission part 24 can be regarded as a rigid body, and there is no mechanism movement inside. Different from the above embodiments, the transmission part in the following embodiments may be a mechanism capable of mechanical movement.

47 , 48 and 49 show the schematic structure of the piezoelectric electroacoustic device 60 of the fifteenth embodiment. As shown in FIGS. 47-49 , the piezoelectric electro-acoustic device 60 may include an isolation film 25 , a hard vibration plate 21 , a washer 22 , a transmission part 61 , a diaphragm 26 , a piezoelectric sheet 23 and a rear case 31 . Except for the transmission part 61 , the structures, positional relationships and assembly relationships of the components listed above are the same as those described above, and will not be repeated here. The piezoelectric electroacoustic device 60 includes the rear case 31 without the front case 41, which is merely an example. In other embodiments, the piezoelectric electro-acoustic device 60 may have the front case 41 without the rear case 31 , or both the rear case 31 and the front case 41 , or neither the front case 41 nor the rear case 31 . In addition, the isolation film 25 and the vibrating film 26 in the piezoelectric electro-acoustic device 60 can be set as required, and are not required.

As shown in FIG. 50 , the transmission part 61 may include a support 611 and a plurality of transmission rods 612 .

The support 611 can be approximately a ring-shaped structure surrounding a circumference, such as a circular ring. Circumferential and axial directions can be defined for the support 611 . The circumferential direction refers to the surrounding direction of the annular structure, and the axial direction refers to the extension direction of the axis around which the annular structure surrounds. The axis is not limited to being an axis of symmetry, and any straight line passing through the cavity of the annular structure and not intersecting with the annular structure can be referred to as an axis. The opposite ends in the axial direction of the support 611 may be referred to as the force applying end 611a and the linkage end 611b, respectively.

In other embodiments, the support 611 is not limited to being a circular ring, but can also be a square ring, a special-shaped ring, or the like. Alternatively, the support 611 may be an open frame structure that is not closed, such as approximately V-shape, C-shape, etc.; In fact, the structure of the support 611 can be correspondingly designed in the embodiments of the present application, and the above is just an example.

The transmission rod 612 may be rod-shaped (longer than the radial dimension), eg, approximately cylindrical rod. The two opposite end faces in the length direction of the transmission rod 612 can be inclined at a certain angle relative to the axis of the transmission rod 612 (extending along the length direction of the transmission rod 612 ), rather than being perpendicular to the axis, so as to be aligned with the rigid vibration plate 21 Connected to the diaphragm 26 (described below). The lengths of all transmission rods 612 may be substantially the same. In other embodiments, the transmission rod 612 is not limited to be a cylindrical rod, for example, it can also be a prismatic rod (with a polygonal cross section). The two opposite end surfaces in the length direction of the transmission rod 612 may not need to be inclined relative to the axis of the transmission rod 612, but are substantially perpendicular to the axis. All drive rods 612 may not be all the same length.

As shown in FIG. 50 , the transmission rod 612 may include a fulcrum end 612a, a force receiving portion 612b and a transmission end 612c. The fulcrum end 612a and the transmission end 612c are the opposite ends of the transmission rod 612 in the longitudinal direction, respectively, and the force receiving portion 612b is the part located between the fulcrum end 612a and the transmission end 612c. The distance from the force-receiving part 612b to the fulcrum end 612a (substantially equal to the distance from the force-applying end 611a to the fulcrum end 612a) is smaller than the distance from the force-receiving part 612b to the transmission end 612c (substantially equal to the distance from the force-applying end 611a to the transmission end 612c), that is, compared with The transmission end 612c and the force receiving portion 612b are closer to the fulcrum end 612a (ie, the force applying end 611a is closer to the fulcrum end 612a). For example, the distance from the force receiving portion 612b to the fulcrum end 612a is approximately half the distance from the force receiving portion 612b to the transmission end 612c.

As shown in FIG. 50 , the force-receiving portion 612b is fixedly connected to the force-applying end 611a. For example, the transmission rod 612 can penetrate the surface of the force-applying end 611a, so that the force-receiving portion 612b is basically embedded in the surface of the force-applying end 611a. Alternatively, the force-receiving portion 612b may be completely exposed above the surface at the force-applying end 611a, and may be connected to the surface by means of bonding, welding, or clipping. Other parts of the transmission rod 612 except the force-receiving portion 612b are not connected to the support 611 , but deviate from the support 611 .

The number of the transmission rods 612 can be designed according to requirements, for example, it can be greater than or equal to two, such as two, three, four, five, ten, sixteen and so on. All the transmission rods 612 can be arranged on different planes from each other, that is, any two transmission rods 612 are neither parallel nor intersecting, and can be regarded as straight lines on different planes. Exemplarily, there may be sixteen transmission rods 612 in FIG. 50 . As shown in FIG. 50 and FIG. 51 , each transmission rod 612 can be approximated as a straight generatrix of a single-leaf hyperboloid, that is, sixteen transmission rods 612 can approximate a single-leaf hyperboloid. Of course, the arrangement of approximately forming a single-leaf hyperboloid is only an example, and the embodiments of the present application are not limited thereto.

FIG. 52 shows the assembly relationship between the transmission portion 61 , the rigid vibration plate 21 , the diaphragm 26 , and the piezoelectric sheet 23 .

As shown in FIG. 52 , the transmission part 61 is located between the hard vibration plate 21 and the vibration film 26 . The support 611 is spaced from the hard vibration plate 21 , the support 611 can be installed on the diaphragm 26 , the axial direction of the support 611 can be substantially coincident with the thickness direction of the diaphragm 26 , and the linkage end 611 b can be connected to the diaphragm 26 . Connecting (eg gluing, welding or snapping, etc.). The linkage end 611b may at least partially overlap with the vibration area of the piezoelectric sheet 23. For example, the orthographic projection of the linkage end 611b on the piezoelectric sheet 23 basically falls within the vibration area 23a. Ideally, the linkage end 611b is symmetrical about the center of the vibration area 23a. . In other embodiments, the linkage end 611b may also at least partially overlap the vibration region of the piezoelectric sheet 23 in other vibration modes.

As shown in FIG. 52 , all the transmission rods 612 are connected between the hard vibration plate 21 and the vibration film 26 . Taking one of the transmission rods 612 as an example, the fulcrum end 612a of the transmission rod 612 is connected (eg, glued) to the diaphragm 26 , and the transmission end 612c is connected (eg, glued) to the hard vibration plate 21 . The transmission rod 612 is inclined relative to the hard vibration plate 21 and the vibration film 26 , that is, the transmission rod 612 is not perpendicular to the hard vibration plate 21 and the vibration film 26 . The end face of the fulcrum end 612a (that is, one of the two opposite end faces in the length direction of the transmission rod 612 mentioned above, the same below) can be fitted to the surface of the diaphragm 26, and the end face of the transmission end 612c is fitted to the hard vibration the surface of the board 21 . From the above, when the two end surfaces can be inclined rather than perpendicular to the axis of the transmission rod 612, the two end surfaces can better fit with the surface of the hard vibration plate 21 and the surface of the diaphragm 26, Therefore, the transmission rod 612 can be reliably connected with the hard vibration plate 2 and the vibration film 26 .

In the fifteenth embodiment, when the piezoelectric sheet 23 drives the diaphragm 26 to vibrate, the diaphragm 26 will drive the support 611 to vibrate. The force will create a moment on the transmission rod 612, so that the force receiving portion 612b and the transmission end 612c can rotate around the fulcrum end 612a. In this way, the transmission end 612c will transmit the vibration to the hard vibration plate 21 to vibrate the hard vibration plate 21 . It can be seen that the transmission part 61 is essentially a lever mechanism, the transmission rod 612 acts as a lever, and the support 611 can provide lever force. It should be noted that the rotation angle of the transmission rod 612 is extremely small.

FIG. 53( a )- FIG. 53( c ) show the movement process of the support 611 and the transmission rod 612 . 53(a) shows that when the diaphragm 26 is in a balanced state without vibration, the support 611 and the two transmission rods 612 are also in a balanced position. Figure 53(b) shows that when the diaphragm 26 bends and vibrates in a certain direction (for example, downward), the displacement of the support 611 reaches t1, and the displacement of the force-receiving part 612b is also basically t1 (because the force-receiving part 612b and the support 611 can be equivalent to a rigid body), the angle between the two transmission rods 612 and the diaphragm 26 is reduced. Figure 53(c) shows that when the diaphragm 26 bends and vibrates in the other direction (eg upward), the displacement of the support 611 reaches t2, the displacement of the force receiving portion 612b is also basically t2, the two transmission rods 612 and the diaphragm 26 angle increases. It should be noted that the rotation angle of the transmission rod 612 is extremely small, so that both t1 and t2 are extremely small, and both t1 and t2 may be in the order of micrometers, such as tens of micrometers to hundreds of micrometers.

Figure 54 takes a transmission rod 612 as an object, and describes the relationship between the displacement of the transmission end 612c and the displacement of the force receiving part 612b when the transmission rod 612 is in different positions, wherein the transmission rod 612 is taken from the position of Figure 53(a) Take the rotation to the position shown in Fig. 53(c) as an example.

As shown in FIG. 54, the transmission rod 612 can be rotated from the initial position by a certain angle a around the fulcrum end 612a to reach another position, wherein the angle a is extremely small. During this process, the force receiving portion 612b and the transmission end 612c also rotate around the fulcrum end 612a to a new position. A connecting line m1 is drawn from the old position of the force-receiving portion 612b to the new position, and the connecting line m1 basically coincides with the circumferential track of the force-receiving portion 612b. A connection line m2 is drawn from the old position of the transmission end 612c to the new position, and the connection line m2 basically coincides with the circumferential track of the transmission end 612c. Since the distance from the force receiving portion 612b to the fulcrum end 612a may be one third of the total length of the transmission rod 612, according to the related principle of similar triangles, the length of the connecting line m2 is approximately three times the length of the connecting line m1. It is easy to understand that the distance from the force-receiving portion 612b to the fulcrum end 612a may also be other values, which are not limited to one third of the total length of the transmission rod 612 . Correspondingly, the length multiple relationship between the connection line m2 and the connection line m1 can be changed accordingly.

The line n1 is obtained by decomposing the connecting line m1 according to the parallelogram rule, wherein the extending direction of the line n1 is substantially perpendicular to the diaphragm 26 , and the line n1 represents the vibration displacement of the force receiving portion 612b. It is easy to understand that when the angle a is extremely small, the length difference between the connection line m1 and the line n1 is extremely small, and it can be basically considered that the two are of equal length. Similarly, the line n2 is obtained by decomposing the connecting line m2 according to the parallelogram rule, wherein the extending direction of the line n2 is substantially perpendicular to the diaphragm 26, and the line n2 represents the vibration displacement of the transmission end 612c. It is easy to understand that when the angle a is extremely small, the length difference between the connection line m2 and the line n2 is extremely small, and it can be basically considered that the two are of equal length.

As can be seen from the above, the length of the line n2 may be approximately equal to three times the length of the line n1, that is, the vibration displacement of the transmission end 612c may be approximately equal to three times the vibration displacement of the force receiving portion 612b. Since the vibration displacement of the force-receiving part 612b is basically equal to the vibration displacement of the diaphragm 26, and the vibration displacement of the transmission end 612c is basically equal to the vibration displacement of the hard vibration plate 21, the lever mechanism composed of the support 611 and the transmission rod 612 can be used. The small vibration displacement of the diaphragm 26 is amplified into the large vibration displacement of the rigid vibration plate 21 .

To sum up, the fifteenth embodiment can improve the vibration displacement of the hard vibration plate 21 by designing the transmission part 61 and through the displacement amplification effect of the transmission part 61 . In addition, the design of the fifteenth embodiment can also enable the piezoelectric electroacoustic device 60 to have a larger effective vibration area. Therefore, under the dual design of increasing the vibration displacement and increasing the effective vibration area, the piezoelectric electro-acoustic device 60 can push a larger amount of air, resulting in better low-frequency performance and overall sound quality.

As shown in FIG. 55 , FIG. 56 , FIG. 57 and FIG. 58 , in the sixteenth embodiment, the transmission part 71 of the piezoelectric electro-acoustic device 70 may include a rotating shaft 712 and a transmission arm, which is different from the fifteenth embodiment described above. 711.

The rotating shaft 712 may be a cylindrical shaft. The rotating shaft 712 can be made of metal or high polymer. The opposite ends of the rotating shaft 712 can be fixedly connected to the wall of the washer 22 , for example, the opposite ends of the rotating shaft 712 can be plugged on the wall of the washer 22 . In this design, the gasket 22 can be fabricated from rigid materials such as metals (eg, aluminum, aluminum alloys, steel, steel alloys), hard plastics (polycarbonate, polycarbonate composite fiberglass), carbon fiber, and the like.

The rotating shaft 712 may be located between the hard vibration plate 21 and the vibration film 26 . In other embodiments, at least one end of the rotating shaft 712 can pass through the wall of the washer 22 , and the end of the rotating shaft 712 passing through the washer 22 can be bent and fixedly connected to the rear case 31 or the front case 41 . Even the end of the rotating shaft 712 passing through the gasket 22 can be fixedly connected to other structures in the electronic device 10 except the piezoelectric electroacoustic device 70 , for example, the middle frame 12 or the back cover 13 .

As shown in FIG. 58 , the transmission arm 711 may include a linkage end 711a, a connection arm 711b and a transmission end 711c which are bent and connected in sequence. The included angle between the linkage end 711a and the connecting arm 711b, and the included angle between the connecting arm 711b and the transmission end 711c can be designed as required, for example, both can be approximately ninety degrees. The linkage end 711a and the transmission end 711c may be located on opposite sides of the connecting arm 711b, respectively. The connecting arm 711b is rotatably connected with the rotating shaft 712, for example, the rotating shaft 712 can pass through the connecting arm 711b, and the connecting arm 711b and the rotating shaft 712 form a rotating pair. The connecting position of the rotating shaft 712 on the connecting arm 711b may be closer to the linkage end 711a, but farther from the transmission end 711c. For example, the distance from the axis of the rotating shaft 712 to the center of the linkage end 711a may be one third of the distance from the axis of the rotating shaft 712 to the center of the transmission end 711c.

As shown in FIG. 58 and FIG. 56 , the transmission arm 711 may be located between the hard vibration plate 21 and the vibration film 26 . Wherein, the linkage end 711a may be connected to the vibrating membrane 26 (eg, glued, welded or clamped), for example, may be located near the center of the vibration area 23a of the piezoelectric sheet 23 . Alternatively, the linkage end 711a may at least partially overlap the vibration region of the piezoelectric sheet 23 in the higher-order mode. The transmission end 711c can be connected with the rigid vibration plate 21 (eg, glued, welded or snapped). Therefore, when the diaphragm 26 vibrates, it can drive the linkage end 711a to vibrate, thereby driving the transmission end 711c and the hard vibration plate 21 to vibrate.

The transmission arm 711 can be made of materials with lower density and less deformation, the material density of the transmission arm 711 can be less than or equal to 3000kg/m ³ , and the modulus of the material of the transmission arm 711 can be greater than or equal to 1GPa. For example, the transmission arm 711 can be made of metals such as aluminum and aluminum alloys, or fiber composite materials such as carbon fiber and glass fiber, or high polymers such as polycarbonate.

The transmission part 71 in the sixteenth embodiment is essentially a lever mechanism, in which the rotating shaft 712 serves as a fulcrum, the diaphragm 26 provides power, and the distance from the rotating shaft 712 to the linkage end 711a and the distance from the rotating shaft 712 to the transmission end 711c serve as two lever arms respectively. . According to the lever principle, since the distance from the rotating shaft 712 to the linkage end 711a is smaller than the distance from the rotating shaft 712 to the transmission end 711c, during vibration, the vibration displacement of the linkage end 711a is smaller than that of the transmission end 711c. Therefore, by using the lever mechanism constituted by the transmission arm 711 and the rotating shaft 712 , a small vibration displacement of the diaphragm 26 can be amplified into a large vibration displacement of the rigid vibration plate 21 . For example, the vibration displacement of the rigid vibration plate 21 may be approximately four times the vibration displacement of the diaphragm 26 .

It is easy to understand that one or more transmission parts 71 may be provided. When there are a plurality of them, the transmission parts 71 are spaced apart from each other. Using a plurality of transmission parts 71 can drive the hard vibration plate 21 at multiple positions, so that the hard vibration plate 21 can vibrate more smoothly.

Therefore, by designing the transmission part 71 in the sixteenth embodiment, the vibration displacement of the hard vibration plate 21 can be increased through the displacement amplification effect of the transmission part 71 . In addition, the mechanism design of the transmission part 71 is simpler, the manufacture and assembly are easy, and the product reliability is also better. In addition, the design of the sixteenth embodiment can also enable the piezoelectric electroacoustic device 70 to have a larger effective vibration area. Therefore, under the dual design of improving the vibration displacement and increasing the effective vibration area, the piezoelectric electro-acoustic device 70 can push a larger amount of air, resulting in better low-frequency performance and overall sound quality.

The solutions of the above embodiments of the present application can greatly improve the low-frequency performance of the piezoelectric electro-acoustic device compared with the traditional piezoelectric electro-acoustic device. For example, FIG. 59 shows the sound pressure level (ordinate)-frequency (abscissa) curve of the piezoelectric electroacoustic device 30 (as shown in FIGS. 33 to 35 ) in the twelfth embodiment, which is different from the conventional piezoelectric Sound pressure level-frequency curves of electroacoustic devices. Among them, the higher the sound pressure level, the better the low frequency performance. By comparison, it can be seen that in the frequency band below 500 Hz, the sound pressure level of the traditional piezoelectric electroacoustic device is about 70dB-90dB, while the sound pressure level of the piezoelectric electroacoustic device 30 of the twelve embodiment is about 75dB-100dB. It can be seen that the low frequency performance of the piezoelectric electro-acoustic device 30 of the twelfth embodiment is greatly improved compared with the traditional piezoelectric electro-acoustic device.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited to this. should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

A piezoelectric electro-acoustic device, characterized in that:

It includes a piezoelectric sheet, a transmission part and a hard vibration plate; the piezoelectric sheet and the hard vibration plate are stacked and arranged at intervals, the piezoelectric sheet includes a vibration area, and the area of the hard vibration plate is larger than that of the hard vibration plate. The area of the vibration area; the transmission part is arranged between the center of the vibration area and the hard vibration plate, and is fixedly connected with the hard vibration plate; the vibration area is used for vibration to induce the transmission The part vibrates, so that the transmission part drives the hard vibration plate to vibrate.
The piezoelectric electroacoustic device according to claim 1, characterized in that:

The area of the hard vibration plate is greater than or equal to the area of the piezoelectric sheet.
The piezoelectric electro-acoustic device according to claim 1 or 2, characterized in that:

At least a part of the vibration region overlaps the hard vibration plate.
The piezoelectric electro-acoustic device according to any one of claims 1-3, characterized in that,

The modulus of the rigid vibration plate is greater than or equal to 1 GPa.
The piezoelectric electroacoustic device according to claim 4, wherein:

The material of the hard vibration plate is a composite material composed of polymethacrylimide foam and aluminum, a composite material composed of polymethacrylimide foam and aluminum alloy, and a polymethacrylimide foam and carbon fiber. composite materials, composite materials composed of polymethacrylimide foam and glass fiber, composite materials composed of balsa wood and aluminum, composite materials composed of balsa wood and aluminum alloys, foamed aluminum, and foamed aluminum alloys. any kind.
The piezoelectric electro-acoustic device according to any one of claims 1-5, characterized in that,

The transmission part is an integral part.
The piezoelectric electro-acoustic device according to any one of claims 1-5, characterized in that,

The transmission part is integrally connected with the hard vibration plate.
The piezoelectric electro-acoustic device according to any one of claims 1-5, characterized in that,

The transmission part includes a support and at least two transmission rods; the support includes a force-applying end and a linkage end, and the force-applying end of the support is located between the hard vibration plate and the linkage end of the support; the At least two transmission rods are arranged at different planes from each other; the transmission rod is fixedly connected with the force-applying end of the support, and is arranged obliquely with the hard vibration plate; the transmission rod includes a fulcrum end and a transmission end, the The fulcrum end of the transmission rod and the transmission end of the transmission rod are arranged on both sides of the force application end of the support, and the distance between the force application end of the support and the fulcrum end of the transmission rod is smaller than the distance of the support. the distance between the force-applying end and the transmission end of the transmission rod; the transmission end of the transmission rod is fixedly connected with the hard vibration plate;

The vibration area is used to vibrate to cause the linkage end of the support and the force-applying end of the support to vibrate, so that the force-applying end of the support drives the transmission end of the transmission rod to rotate around the fulcrum end of the transmission rod, So that the transmission end of the transmission rod drives the hard vibration plate to vibrate.
The piezoelectric electro-acoustic device according to claim 8, characterized in that:

The transmission rod is set as a single-leaf hyperboloid straight generatrix.
The piezoelectric electro-acoustic device according to any one of claims 1-5, characterized in that,

The transmission part includes a rotating shaft and a transmission arm; the rotating shaft is arranged between the hard vibration plate and the piezoelectric sheet; the transmission arm is rotatably connected with the rotating shaft, and the transmission arm includes a linkage end and a transmission arm. The linkage end of the transmission arm and the transmission end of the transmission arm are located on both sides of the rotating shaft, and the distance between the linkage end of the transmission arm and the rotating shaft is smaller than the distance between the transmission end of the transmission arm and the rotating shaft. The distance between the rotating shafts, the transmission end of the transmission arm is fixedly connected with the hard vibration plate;

The vibration area is used to vibrate to cause the linkage end of the transmission arm to vibrate, so that the transmission end of the transmission arm rotates around the rotating shaft, so that the transmission end of the transmission arm drives the rigid vibration plate to vibrate.
The piezoelectric electro-acoustic device according to claim 10, wherein:

The transmission arm includes a connection arm, and the connection arm connects the linkage end and the transmission end; the connection arm is rotatably connected with the rotating shaft; both the linkage end and the transmission end are formed with the connection arm. Angle setting.
The piezoelectric electro-acoustic device according to any one of claims 1-11, characterized in that,

The piezoelectric electro-acoustic device includes an isolation film and a gasket; the isolation film is an elastic material; the isolation film and the hard vibration plate are stacked and arranged, and the isolation film is located on the hard vibration plate away from the one side of the piezoelectric sheet; the washer is located between the isolation film and the piezoelectric sheet, and the washer connects the periphery of the isolation film and the piezoelectric sheet, and is connected with the isolation film and the piezoelectric sheet. The piezoelectric sheet encloses a closed cavity; the hard vibration plate and the transmission part are arranged in the cavity.
The piezoelectric electroacoustic device according to claim 12, wherein:

The area of the isolation membrane between the washer and the hard vibration plate is curved and arched.
The piezoelectric electro-acoustic device according to any one of claims 1-11, characterized in that,

The piezoelectric electro-acoustic device includes a washer, the washer is an elastic material, the washer is located between the hard vibration plate and the piezoelectric sheet, and the washer connects the periphery of the hard vibration plate with the The periphery of the piezoelectric sheet forms a closed cavity with the hard vibration plate and the piezoelectric sheet; the transmission part is arranged in the cavity.
The piezoelectric electro-acoustic device according to any one of claims 1-11, characterized in that,

The piezoelectric electro-acoustic device includes a vibrating membrane and a washer; the vibrating membrane and the piezoelectric sheet are stacked and arranged, the piezoelectric sheet is located on one side or both sides of the vibrating membrane, and the piezoelectric sheet is The periphery shrinks inward from the periphery of the vibrating film; the washer is located between the hard vibration plate and the piezoelectric sheet, and the washer connects the periphery of the hard vibrating plate and the periphery of the vibrating film, and form a closed cavity with the hard vibration plate and the vibration film; the transmission part is arranged in the cavity.
The piezoelectric electroacoustic device according to claim 15, wherein:

The area of the diaphragm between the washer and the piezoelectric sheet is curved and arched.
The piezoelectric electroacoustic device according to claim 15 or 16, characterized in that,

The diaphragm is provided with a through hole, and the through hole communicates with the cavity.
The piezoelectric electro-acoustic device according to any one of claims 1-11, characterized in that,

The piezoelectric electro-acoustic device includes an isolation film, a washer and a vibration film; the isolation film is an elastic material; the isolation film, the hard vibration plate and the vibration film are stacked in sequence; the washer is located at the Between the isolation diaphragm and the piezoelectric sheet, the gasket connects the periphery of the isolation diaphragm and the diaphragm, and forms a closed cavity with the isolation diaphragm and the diaphragm; the The piezoelectric sheet is located on one side or both sides of the vibrating membrane; the hard vibrating plate and the transmission part are both arranged in the cavity.
The piezoelectric electro-acoustic device according to any one of claims 1-14, characterized in that,

The piezoelectric electro-acoustic device includes a rear casing, which is arranged on the side of the piezoelectric sheet away from the hard vibration plate; the rear casing is connected to the periphery of the piezoelectric sheet and is connected to the piezoelectric sheet. The piezoelectric sheet encloses the back cavity of the piezoelectric electro-acoustic device.
The piezoelectric electro-acoustic device according to any one of claims 15-18, characterized in that,

The piezoelectric electro-acoustic device includes a back shell, which is arranged on the side of the vibrating membrane away from the hard vibration plate; the back shell is connected with the periphery of the vibrating membrane, and is connected with the The diaphragm encloses the back cavity of the piezoelectric electro-acoustic device.
The piezoelectric electro-acoustic device according to any one of claims 1-11 and 14-17, characterized in that,

The piezoelectric electro-acoustic device includes a front case, which is arranged on the side of the hard vibration plate away from the piezoelectric sheet; the front case is connected to the periphery of the hard vibration plate, and is The front cavity of the piezoelectric electro-acoustic device is enclosed with the hard vibration plate.
The piezoelectric electroacoustic device according to any one of claims 12, 13, 18, and 19, characterized in that:

The piezoelectric electro-acoustic device includes a front case, which is arranged on the side of the isolation film away from the hard vibration plate; the front case is connected with the periphery of the isolation film, and is connected with the isolation film. The isolation film encloses the front cavity of the piezoelectric electro-acoustic device.
The piezoelectric electro-acoustic device according to any one of claims 1-22, characterized in that,

The vibration region is the vibration region of the piezoelectric sheet in a first-order mode.
An electronic device, characterized in that:

It comprises a casing and the piezoelectric electro-acoustic device according to any one of claims 1 to 23; the casing has a sound outlet connecting the inside and outside of the casing; the piezoelectric electro-acoustic device is mounted on the inside the casing, and can emit sound through the sound outlet hole.