Piezoelectric driver, piezoelectric motor, camera module and electronic device

Abstract

This application provides a piezoelectric actuator, a piezoelectric motor, a camera module, and an electronic device. The piezoelectric actuator includes a friction head and a stacked piezoelectric element; the stacked piezoelectric element includes a piezoelectric body, which includes a first region along a first preset direction; in the first region, the piezoelectric body includes a first external electrode, a third external electrode, a first ground layer, a signal layer, and multiple piezoelectric layers; the multiple piezoelectric layers are arranged sequentially at intervals along the first preset direction, each piezoelectric layer having two opposing first surfaces and a second surface bent and connected to the first surfaces, wherein the relative directions of the two first surfaces are parallel to the first preset direction; the first ground layer and the signal layer are respectively connected to different first surfaces, so that the electrodes on opposite sides of the same piezoelectric layer are the signal layer and the first ground layer, respectively; the first external electrode and the third external electrode are both connected to the second surface, and the first external electrode is electrically connected to the first ground layer, and the third external electrode is electrically connected to the signal layer.

Description

Technical Field

[0001] This application relates to the field of piezoelectric drive technology, specifically to a piezoelectric actuator, a piezoelectric motor, a camera module, and electronic equipment. Background Technology

[0002] A piezoelectric motor is a piezoelectric device that utilizes the inverse piezoelectric effect (the inverse piezoelectric effect refers to the mechanical deformation of a piezoelectric material when an electric field is applied along its polarization direction, and the deformation disappears when the electric field is removed) to excite a piezoelectric actuator (i.e., the stator) to vibrate at a specific frequency. Through friction, this vibration is converted into macroscopic linear or rotational motion of the actuator. Based on the number of layers of piezoelectric material used in the stator, piezoelectric motors can be classified into single-layer and multi-layer piezoelectric motors. Multi-layer piezoelectric motors generally offer superior driving performance compared to single-layer motors. However, multi-layer piezoelectric motors in current technologies cannot maximize the excitation of the stator's vibration at a specific operating frequency, leading to insufficient driving force. Summary of the Invention

[0003] This application provides a piezoelectric actuator capable of achieving greater driving force, as well as a piezoelectric motor, camera module, and electronic device including the piezoelectric actuator.

[0004] In a first aspect, this application provides a piezoelectric actuator, the piezoelectric actuator comprising: a friction head and a stacked piezoelectric element, the friction head being connected to the stacked piezoelectric element; The stacked piezoelectric element includes a piezoelectric body, which includes a first region along a first preset direction; in the first region, the piezoelectric body includes: a first external electrode, a third external electrode, a first ground layer, a signal layer, and multiple piezoelectric layers; Multiple piezoelectric layers are arranged sequentially at intervals along a first preset direction. Each piezoelectric layer has two opposing first surfaces and a second surface bent and connected to the first surfaces. The relative directions of the two first surfaces are parallel to the first preset direction. The first ground layer and the signal layer are respectively connected to different first surfaces, so that the electrodes on opposite sides of the same piezoelectric layer are the signal layer and the first ground layer, respectively; Both the first external electrode and the third external electrode are connected to the second surface, with the first external electrode electrically connected to the first ground layer and the third external electrode electrically connected to the signal layer.

[0005] Secondly, this application also provides a piezoelectric motor, which includes a carrier, a mover, and a piezoelectric actuator. The piezoelectric actuator is connected to the carrier, the mover is movably connected to the carrier, and the piezoelectric actuator abuts against the mover to drive the mover to move.

[0006] Thirdly, this application also provides a camera module, which includes a piezoelectric actuator.

[0007] Fourthly, this application also provides an electronic device, which includes a device body and a camera module, wherein the camera module is mounted on the device body. Attached Figure Description

[0008] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the implementation will be briefly introduced below. Obviously, the drawings described below are some implementations of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0009] Figure 1 This is a schematic diagram of a piezoelectric actuator provided in an embodiment of this application.

[0010] Figure 2 for Figure 1 An exploded view of the piezoelectric actuator shown.

[0011] Figure 3 This is a schematic diagram of a piezoelectric body provided in an embodiment of this application.

[0012] Figure 4 for Figure 3 The diagram shows a polarization mode of a piezoelectric body.

[0013] Figure 5 for Figure 3 A schematic diagram of another polarization mode of the piezoelectric body shown.

[0014] Figure 6 for Figure 3 A schematic diagram of another polarization mode of the piezoelectric body shown.

[0015] Figure 7 for Figure 3 A schematic diagram of another polarization mode of the piezoelectric body shown.

[0016] Figure 8 An exploded view of the piezoelectric body layer stack provided in the embodiments of this application.

[0017] Figure 9 This is a schematic diagram of the structure of the first grounding layer provided in an embodiment of this application.

[0018] Figure 10 This is a schematic diagram of the structure of the second grounding layer provided in an embodiment of this application.

[0019] Figure 11 This is a diagram showing the relative positions of the first external electrode, the second external electrode, and the third external electrode provided in an embodiment of this application.

[0020] Figure 12 Another relative positional relationship diagram of the first external electrode, the second external electrode, and the third external electrode provided in the embodiments of this application.

[0021] Figure 13 A schematic diagram of a piezoelectric body provided in another embodiment of this application.

[0022] Figure 14 This is a schematic diagram of a piezoelectric body provided in yet another embodiment of this application.

[0023] Figure 15 This is a schematic diagram of a piezoelectric body provided in yet another embodiment of this application.

[0024] Figure 16 for Figure 15 A simplified schematic diagram illustrating the polarization mode.

[0025] Figure 17 This is a schematic diagram of a piezoelectric body provided in yet another embodiment of this application.

[0026] Figure 18 for Figure 17 A simplified schematic diagram illustrating the polarization mode.

[0027] Figure 19 This is a schematic diagram of a piezoelectric body provided in yet another embodiment of this application.

[0028] Figure 20 for Figure 19 A simplified schematic diagram illustrating the polarization mode.

[0029] Figure 21 This is a schematic diagram of a piezoelectric body provided in yet another embodiment of this application.

[0030] Figure 22 for Figure 21 A simplified schematic diagram illustrating the polarization mode.

[0031] Figure 23 This is a schematic diagram of a piezoelectric motor provided in an embodiment of this application.

[0032] Figure 24 This is a schematic diagram of a camera module provided in an embodiment of this application.

[0033] Figure 25 This is a schematic diagram of another camera module provided in an embodiment of this application.

[0034] Figure 26 A schematic diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0036] In this document, references to "embodiment" or "implementation" mean that a particular feature, structure, or characteristic described in connection with an embodiment or implementation may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] The stator (i.e., piezoelectric actuator) of a single-layer piezoelectric motor is generally made by sintering powder into a sample of the target size, or by sintering it into a large block and then cutting it into the target size. Only the surface is covered with electrodes, and there are no internal electrodes. The advantage of this is that the process is simple and the cost is low, but the size and operating voltage are generally large, making it difficult to miniaturize.

[0038] The stator (i.e., piezoelectric actuator) of a multilayer piezoelectric motor is generally composed of stacked single piezoelectric layers to form a piezoelectric stack, or by stacking film strips using a casting method to form a precise multilayer structure. The electrodes between the layers of a multilayer piezoelectric motor are in parallel. Assuming the number of layers is n, applying a voltage U will achieve the driving effect of n*U voltage found in a single-layer piezoelectric motor (of the same size and specifications). Compared to single-layer piezoelectric motors, multilayer piezoelectric motors have both internal and external electrodes, which allows for greater diversity in electrode design and polarization, resulting in a variety of different effects.

[0039] Different internal electrode designs have a crucial impact on the performance of piezoelectric motors in engineering practice. Multilayer piezoelectric motors provided in related technologies cannot maximize the excitation of stator vibration at a specific operating frequency, leading to insufficient driving force. An effective solution is to amplify the vibration displacement or driving force by adding auxiliary structures such as cantilever beams; however, this increases the overall structural complexity, assembly tolerances, and cost, and also reduces the advantages in miniaturization.

[0040] Based on this, this application aims to provide a solution that can solve, but is not limited to, the above-mentioned technical problems, the details of which will be described in subsequent embodiments.

[0041] Please refer to Figure 1 This application provides a piezoelectric actuator 100, which can also be referred to as a stacked piezoelectric actuator, piezoelectric actuator, stator, etc. The piezoelectric actuator 100 is used to generate high-frequency micro-amplitude vibrations to convert its own micro-motion into the macro-motion of the driven component. The motion type of the piezoelectric actuator 100 can be, but is not limited to, elliptical motion, oblique motion, etc. Elliptical motion will be used as an example in the following description.

[0042] To facilitate subsequent explanations and understanding of the accompanying drawings, Figure 1 The viewpoint shown defines an XYZ Cartesian coordinate system. The X-axis is parallel to the length direction of the piezoelectric actuator 100, the Y-axis is parallel to the width direction of the piezoelectric actuator 100, and the Z-axis is parallel to the height direction of the piezoelectric actuator 100. Please refer to this location for a further description of the XYZ coordinate system.

[0043] The piezoelectric actuator 100 includes a friction head 10 and a stacked piezoelectric element 20, with the friction head 10 connected to the stacked piezoelectric element 20.

[0044] The function of the laminated piezoelectric element 20 is to generate high-frequency micro-amplitude vibration, which in turn drives the friction head 10 to move.

[0045] The friction head 10 is used to drive the driven component directly or indirectly through friction, converting the microscopic motion of the laminated piezoelectric element 20 into the macroscopic motion of the driven component while ensuring reliability. The number of friction heads 10 can be one, two, or more than two. The shape of the friction head 10 can be cylindrical, semi-cylindrical, hemispherical, cuboid, triangular pyramid, etc. The material of the friction head 10 can be metals or alloys such as copper, iron, and aluminum, alumina (Al2O3), silicon oxide (SiO2), zirconium oxide (ZrO2), or wear-resistant materials such as carbon fiber and polyester fiber. The friction head 10 can be connected to any side of the laminated piezoelectric element 20, and the connection method between the friction head 10 and the laminated piezoelectric element 20 can be, but is not limited to, adhesion. For example, the friction head 10 can be bonded to the center position of a side of the laminated piezoelectric element 20 parallel to the XY plane (or XZ plane, or YZ plane).

[0046] Please refer to Figure 1 and Figure 2The stacked piezoelectric element 20 is a stacked structure, comprising a piezoelectric body 23, a first protective layer 21, and a second protective layer 22. The materials of the first protective layer 21 and the second protective layer 22 can be, but are not limited to, piezoelectric materials. The first protective layer 21 and the second protective layer 22 are respectively disposed at opposite ends of the piezoelectric body 23 along a first preset direction F1, that is, the first protective layer 21, the piezoelectric body 23, and the second protective layer 22 are stacked together in sequence. The first protective layer 21 and the second protective layer 22 can protect the circuit in the piezoelectric body 23 and isolate signals, so that the piezoelectric body 23 can work normally. It should be noted that the massage head can be connected to the first protective layer 21, the second protective layer 22, or the piezoelectric body 23, and is not limited here.

[0047] Please refer to Figure 3 and Figure 4 The piezoelectric body 23 includes: a first external electrode 231, a second external electrode 232, a third external electrode 233, a first ground layer 234, a second ground layer 235, a signal layer 236, and multiple piezoelectric layers 237. Here, the "first external electrode 231, second external electrode 232, and third external electrode 233" are defined as external electrodes, and the "first ground layer 234, second ground layer 235, and signal layer 236" are defined as internal electrodes. Subsequent descriptions involving internal and external electrodes will refer to this section.

[0048] Multiple piezoelectric layers 237 (the number of piezoelectric layers 237 is greater than or equal to 2) are arranged sequentially at intervals along a first preset direction F1. Each piezoelectric layer 237 has two opposing first surfaces 2371 and a bend connected to the first surfaces 2371 (see...). Figure 4 The second surface 2372 (see) Figure 3 The relative directions of the two first surfaces 2371 are parallel to a first preset direction F1, which is parallel to the Z-axis direction.

[0049] The piezoelectric layer 237 is a piezoelectric material. The material of the piezoelectric layer 237 can be lead zirconate titanate (PZT) based piezoelectric ceramics, potassium sodium niobate (KNN) based piezoelectric ceramics, barium titanate (BT) based piezoelectric ceramics, lead magnesium niobate-lead indium niobate (PMN-PT) based piezoelectric single crystals, textured ceramics, etc.

[0050] Piezoelectric materials have no polarization direction in their initial state; polarization only occurs under specific conditions. When pressure or an electric field is applied, the positive and negative charges in the piezoelectric material rearrange themselves, resulting in different polarities at the top and bottom ends of the material. This process is called the polarization of the piezoelectric material.

[0051] The piezoelectric layer 237 can be a rectangular sheet, meaning that the projection shape of the piezoelectric layer 237 onto the XY plane can be rectangular. In other embodiments, the projection shape of the piezoelectric layer 237 onto the XY plane can also be circular, elliptical, irregular, etc. This application only uses a rectangle as an example.

[0052] The number of the first ground layer 234, the second ground layer 235, and the signal layer 236 in the first preset direction F1 (Z-axis direction) is greater than or equal to one, and the first ground layer 234, the second ground layer 235, and the signal layer 236 are arranged at intervals in the first preset direction F1. The first ground layer 234, the second ground layer 235, and the signal layer 236 are respectively connected to different first surfaces 2371, so that the electrodes on opposite sides of the same piezoelectric layer 237 are the signal layer 236 and the first ground layer 234, or the electrodes on opposite sides of the same piezoelectric layer 237 are the signal layer 236 and the second ground layer 235.

[0053] The signal layer 236 is mainly used to load AC drive signals during the operation of the piezoelectric actuator 100. The first ground layer 234 and the second ground layer 235 are used for grounding and loading AC drive signals during the operation of the piezoelectric actuator 100. The drive signal can be a square wave, sine wave, sawtooth wave, or other waveforms. The three internal electrodes—the first ground layer 234, the second ground layer 235, and the signal layer 236—can be made of conductive metal or a thin metal layer. The internal electrodes can be tightly bonded to the piezoelectric layer 237 by printing, plating, or other methods. For example, the signal layer 236 can be formed on the first surface 2371 by screen printing conductive silver paste or conductive adhesive.

[0054] If the electrodes on opposite sides of the piezoelectric layer 237 are a signal layer 236 and a first ground layer 234, respectively, the signal layer 236 and the first ground layer 234 are used to form a first electric field. That is, the signal layer 236 and the first ground layer 234 determine the distribution of the first electric field in the piezoelectric layer 237 located between them. The first electric field is used to polarize the piezoelectric layer 237 or drive the piezoelectric layer 237 to vibrate. If the electrodes on opposite sides of the piezoelectric layer 237 are a signal layer 236 and a second ground layer 235, respectively, the signal layer 236 and the second ground layer 235 are used to form a second electric field. That is, the signal layer 236 and the second ground layer 235 determine the distribution of the second electric field in the piezoelectric layer 237 located between them. The second electric field is used to polarize the piezoelectric layer 237 or drive the piezoelectric layer 237 to vibrate.

[0055] For ease of subsequent description, the “signal layer 236 and the first ground layer 234” will be collectively referred to as the “first polarization combination”, and the “piezoelectric layer 237 between the signal layer 236 and the first ground layer 234” will be referred to as the “first piezoelectric layer”; the “signal layer 236 and the second ground layer 235” will be collectively referred to as the “second polarization combination”, and the “piezoelectric layer 237 between the signal layer 236 and the second ground layer 235” will be referred to as the “second piezoelectric layer”. For subsequent descriptions involving the first polarization combination, the second polarization combination, the first piezoelectric layer, and the second piezoelectric layer, please refer to this document.

[0056] The first external electrode 231, the second external electrode 232, and the third external electrode 233 are all connected to the second surface 2372, and are spaced apart from each other to avoid electrical contact. The three external electrodes 231, 232, and 233 can be made of conductive metal or a thin metal layer.

[0057] The first external electrode 231 is electrically connected to the first ground layer 234. When there are multiple first ground layers 234, the first external electrode 231 is electrically connected to all the first ground layers 234 so that the various first ground layers 234 are connected in parallel.

[0058] The second external electrode 232 is electrically connected to the second ground layer 235. When there are multiple second ground layers 235, the second external electrode 232 is electrically connected to all the second ground layers 235 so that the various second ground layers 235 are connected in parallel.

[0059] The third external electrode 233 is electrically connected to the signal layer 236. When there are multiple signal layers 236, the third external electrode 233 is electrically connected to all signal layers 236 so that the signal layers 236 are connected in parallel.

[0060] The main function of each of the external electrodes is to form a connection with the corresponding internal electrode so that the driving signal is applied to the internal electrode. The first polarization combination and the second polarization combination can generate a suitable electric field to polarize the piezoelectric layer 237 or drive the piezoelectric layer 237 to vibrate.

[0061] In the piezoelectric actuator 100 provided in this application, by applying a suitable AC driving signal to the external electrode, each piezoelectric layer 237 can be excited to generate a corresponding vibration mode. Under the coordinated vibration of multiple piezoelectric layers 237, the entire piezoelectric actuator 100 can exhibit a corresponding motion pattern. The piezoelectric actuator 100 can estimate the frequency of the driving signal that can generate microscopic elliptical motion through size optimization and modal analysis. Elliptical motion can be achieved by a single mode, such as the B2 mode (second-order bending mode), or by superimposing multiple modes, such as the L1B2 mode (first-order elongation mode + second-order bending mode) or the B1B2 mode (first-order bending mode + second-order bending mode).

[0062] The piezoelectric actuator 100 provided in this application needs to be polarized to acquire piezoelectric properties and obtain the desired motion form. The polarization of the piezoelectric actuator 100 is achieved through an electric field formed by a first polarization combination and a second polarization combination. It should be noted that the polarization direction of the piezoelectric material after polarization is the same as the direction of the electric field applied when polarizing the piezoelectric material.

[0063] In this application, since the first ground layer 234 is connected to the first external electrode 231 and the second ground layer 235 is connected to the second external electrode 232, the first ground layer 234 and the second ground layer 235 are independent of each other. Because the first ground layer 234 and the second ground layer 235 are independent, the potential of the first ground layer 234 and the potential of the second ground layer 235 can be the same or different. Consequently, the direction of the electric field formed by the first polarization combination (hereinafter referred to as the first electric field) and the direction of the electric field formed by the second polarization combination (hereinafter referred to as the second electric field) can be the same or different. Therefore, the polarization direction of the first piezoelectric layer disposed between the first polarization combinations (hereinafter referred to as the first polarization direction) and the polarization direction of the second piezoelectric layer disposed between the second polarization combinations (hereinafter referred to as the second polarization direction) can be the same or different.

[0064] Therefore, for the piezoelectric actuator 100 provided in this application, its polarization scheme can adopt the following four types (e.g. Figures 4 to 7 As shown in the accompanying drawings of this application, the direction indicated by the hollow arrow represents the polarization direction. The first polarization scheme: the polarization direction of the first piezoelectric layer is from the first ground layer 234 toward the signal layer 236, and the polarization direction of the second piezoelectric layer is from the second ground layer 235 toward the signal layer 236, such as... Figure 4 As shown; The second polarization scheme: the polarization direction of the first piezoelectric layer is from the signal layer 236 toward the first ground layer 234, and the polarization direction of the second piezoelectric layer is from the signal layer 236 toward the second ground layer 235, such as... Figure 5 As shown; The third polarization scheme: the polarization direction of the first piezoelectric layer is from the first ground layer 234 toward the signal layer 236, and the polarization direction of the second piezoelectric layer is from the signal layer 236 toward the second ground layer 235, such as... Figure 6 As shown; The fourth polarization scheme: the polarization direction of the first piezoelectric layer is from the signal layer 236 toward the first ground layer 234, and the polarization direction of the second piezoelectric layer is from the second ground layer 235 toward the signal layer 236, such as... Figure 7 As shown.

[0065] exist Figure 4 Since the polarization direction of the first piezoelectric layer and the polarization direction of the second piezoelectric layer are both "the direction from the ground layer to the signal layer 236", the polarization direction of the first piezoelectric layer and the polarization direction of the second piezoelectric layer are considered to be the same, that is, the polarization direction of this type of piezoelectric actuator 100 is a single direction.

[0066] exist Figure 5 Since the polarization direction of the first piezoelectric layer and the polarization direction of the second piezoelectric layer are both "signal layer 236 toward ground layer", the polarization direction of the first piezoelectric layer and the polarization direction of the second piezoelectric layer are considered to be the same, that is, the polarization direction of this type of piezoelectric actuator 100 is a single direction.

[0067] exist Figure 6 In this context, since the polarization direction of the first piezoelectric layer is "from the ground layer toward the signal layer 236", and the polarization direction of the second piezoelectric layer is "from the signal layer 236 toward the ground layer", the polarization directions of the first piezoelectric layer and the second piezoelectric layer are considered to be opposite. That is, the polarization direction of this type of piezoelectric actuator 100 is two directions.

[0068] exist Figure 7 In this context, since the polarization direction of the first piezoelectric layer is "signal layer 236 toward ground layer" and the polarization direction of the second piezoelectric layer is "ground layer toward signal layer 236", the polarization directions of the first and second piezoelectric layers are considered to be opposite. That is, the polarization direction of this type of piezoelectric actuator 100 is two directions.

[0069] Compared to a piezoelectric actuator 100 with a single polarization direction, a piezoelectric actuator 100 with two polarization directions can excite modes with larger vibration amplitudes, i.e., larger vibration amplitudes, and thus greater driving force and driving speed.

[0070] In related technologies, the first ground layer and the second ground layer of the piezoelectric actuator are connected to the same external electrode, so there is no difference between the first ground layer and the second ground layer. Therefore, for the piezoelectric actuator, its polarization direction must be a single direction, that is, the polarization direction of the piezoelectric actuator is "the direction from the signal layer to the ground layer", or the polarization direction is "the direction from the ground layer to the signal layer".

[0071] Therefore, compared with related technologies, the polarization direction of the piezoelectric actuator 100 provided in this application can be not only a single direction, but also two directions. When two polarization directions are adopted, the piezoelectric actuator 100 provided in this application has a greater driving force and driving speed than the piezoelectric actuators provided in related technologies, that is, the energy density that can be output is greater. Moreover, under the same output energy density, the volume of the piezoelectric actuator 100 provided in this application can be made smaller.

[0072] In summary, in the piezoelectric actuator 100 provided in this application, a suitable driving signal can be applied to the first ground layer 234, the second ground layer 235, and the signal layer 236 through the first external electrode 231, the second external electrode 232, and the third external electrode 233, thereby exciting each piezoelectric layer 237 to generate corresponding vibrations. Under the coordinated vibration of multiple piezoelectric layers 237, the entire piezoelectric actuator 100 can exhibit a corresponding motion pattern. Furthermore, since the first ground layer 234 is connected to the first external electrode 231 and the second ground layer 235 is connected to the second external electrode 232, the first ground layer 234 and the second ground layer 235 are independent of each other. Therefore, the direction of the electric field (hereinafter referred to as the first electric field) formed by the first ground layer 234 and the signal layer 236 can be the same as or different from the direction of the electric field (hereinafter referred to as the first electric field) formed by the second ground layer 235 and the signal layer 236. Therefore, the polarization direction of the piezoelectric layer 237 located between the first ground layer 234 and the signal layer 236 (referred to as the first polarization direction) can be the same as or different from the polarization direction of the piezoelectric layer 237 located between the second ground layer 235 and the signal layer 236 (referred to as the second polarization direction). Specifically, the piezoelectric actuator 100 needs to be polarized to have piezoelectric properties. When the direction of the first electric field used to polarize the piezoelectric layer 237 is the same as the direction of the second electric field, the first polarization direction and the second polarization direction are the same. That is, the first polarization direction is "the direction from the first ground layer 234 to the signal layer 236" and the second polarization direction is "the direction from the second ground layer 235 to the signal layer 236", or the first polarization direction is "the direction from the signal layer 236 to the first ground layer 234" and the second polarization direction is "the direction from the signal layer 236 to the second ground layer 235". For the piezoelectric actuator 100 with the same first polarization direction and second polarization direction, its polarization direction is a single direction. When the direction of the first electric field used to polarize the piezoelectric layer 237 is different from the direction of the second electric field, the first polarization direction and the second polarization direction are different. That is, the first polarization direction is "the direction from the first ground layer 234 to the signal layer 236" and the second polarization direction is "the direction from the signal layer 236 to the second ground layer 235", or the first polarization direction is "the direction from the signal layer 236 to the first ground layer 234" and the second polarization direction is "the direction from the second ground layer 235 to the signal layer 236". For a piezoelectric actuator 100 with different first and second polarization directions, its polarization direction is two directions. Compared with related technologies, when the piezoelectric actuator 100 provided in this application adopts a two-polarization-direction scheme, it has a greater driving force and driving speed, that is, it can output a greater energy density. Moreover, under the same output energy density, the volume of the piezoelectric actuator 100 provided in this application can be made smaller.Furthermore, the polarization direction of the piezoelectric actuator 100 can be a single direction or two directions, indicating that the polarization mode of the piezoelectric actuator 100 is diversified, and the design flexibility is higher, so it can be adapted to more driving scenarios.

[0073] Please refer to Figure 3 and Figure 4 Each signal layer 236 includes multiple signal electrodes X236, which are arranged at intervals. That is, signal electrodes X236 located in the same layer are not connected to each other. It should be noted that "multiple signal electrodes X236" corresponds to "one signal layer 236", not "the entire piezoelectric actuator 100". For example, if one signal layer 236 contains N signal electrodes X236, and if one piezoelectric actuator 100 contains M signal layers 236, then one piezoelectric actuator 100 contains N*M signal electrodes X236.

[0074] Furthermore, the third external electrode 233 includes multiple sub-electrodes X233. The number of sub-electrodes X233 is the same as the number of signal electrodes X236 contained in one signal layer 236, specifically 2, 3, 4, 5, 6, etc. This application only uses 2 as an example. Different sub-electrodes X233 are electrically connected to different signal electrodes X236, that is, the sub-electrodes X233 and signal electrodes X236 are electrically connected in a one-to-one correspondence.

[0075] In this embodiment, since different sub-electrodes X233 are electrically connected to different signal electrodes X236, the different signal electrodes X236 are independent of each other, so that the polarization direction of the piezoelectric layer 237 portion corresponding to different signal electrodes X236 can be the same or different, thereby making the polarization mode of the piezoelectric actuator 100 more diverse, and the design flexibility is higher, so that it can be adapted to more driving scenarios.

[0076] Please refer to Figure 8 and Figure 9 The first ground layer 234 includes a first body portion 2341 and a first lead-out portion 2342. The first lead-out portion 2342 and the first body portion 2341 can be an integral structure or a separate structure. The first body portion 2341 is disposed opposite to the signal layer 236, meaning that the orthographic projection of the first body portion 2341 onto the signal layer 236 at least partially falls within the area of ​​the signal layer 236. The first body portion 2341 is spaced at the periphery of the first surface 2371 of the piezoelectric layer 237 to prevent the first body portion 2341 from directly contacting the external electrode. One end of the first lead-out portion 2342 is connected to the first body portion 2341, and the other end of the first lead-out portion 2342 is connected to the first external electrode 231, so that the first body portion 2341 is electrically connected to the first external electrode 231 through the first lead-out portion 2342.

[0077] Please refer to Figure 8 and Figure 10 The second grounding layer 235 includes a second body portion 2351 and a second lead-out portion 2352. The second lead-out portion 2352 and the second body portion 2351 can be an integral structure or a separate structure. The second body portion 2351 is disposed opposite to the signal layer 236, meaning that the orthographic projection of the second body portion 2351 onto the signal layer 236 at least partially falls within the area of ​​the signal layer 236. The second body portion 2351 is spaced at the periphery of the first surface 2371 of the piezoelectric layer 237 to prevent the second body portion 2351 from directly contacting the external electrode. One end of the second lead-out portion 2352 is connected to the second body portion 2351, and the other end of the second lead-out portion 2352 is connected to the second external electrode 232, so that the second body portion 2351 is electrically connected to the second external electrode 232 through the second lead-out portion 2352.

[0078] Furthermore, the projections of the first lead-out portion 2342 and the second lead-out portion 2352 onto the piezoelectric layer 237 do not overlap. This arrangement facilitates the connection of the first external electrode 231 to the first lead-out portion 2342 and the second external electrode 232 to the second lead-out portion 2352, while ensuring that the first external electrode 231 and the second external electrode 232 are spaced apart.

[0079] Please refer to Figure 8 and Figure 9 The first body portion 2341 has a first end D1 and a second end D2 that are far apart from each other. The first end D1 is closer to the second lead-out portion 2352 than the second end D2. The first lead-out portion 2342 is connected to the second end D2. In short, the first lead-out portion 2342 is connected to the end of the first body portion 2341 that is far apart from the second lead-out portion 2352.

[0080] Please refer to Figure 8 and Figure 10 The second body portion 2351 has a third end D3 and a fourth end D4 that are far apart from each other. The fourth end D4 is closer to the first lead-out portion 2342 than the third end D3. The second lead-out portion 2352 is connected to the third end D3. In short, the second lead-out portion 2352 is connected to the end of the second body portion 2351 that is far away from the first lead-out portion 2342.

[0081] With the above arrangement, the first lead-out portion 2342 and the second lead-out portion 2352 can be kept as far apart as possible, which can better avoid the problem of the first external electrode 231 and the second external electrode 232 coming into contact due to errors during the manufacturing process of the piezoelectric actuator 100.

[0082] At least one of the three ground layers 234, 235, and 236 has an edge flush with the second surface 2372.

[0083] Optionally, at least a portion of the edges of the signal layer 236 are flush with the second surface 2372, such as... Figure 3 As shown, this configuration allows the third external electrode 233 to be flatly connected to each signal layer 236, thereby enabling all signal layers 236 to be connected in parallel through the third external electrode 233.

[0084] Optionally, at least a portion of the edges of the first ground layer 234 are flush with the second surface 2372, such as... Figure 9 As shown, this configuration allows the first external electrode 231 to be flatly connected to the first ground layer 234 of each layer, thereby enabling all the first ground layers 234 to be connected in parallel through the first external electrode 231.

[0085] Optionally, at least a portion of the edges of the second ground layer 235 are flush with the second surface 2372, such as... Figure 10 As shown, this configuration allows the second external electrode 232 to be flatly connected to the second ground layer 235 of each layer, thereby enabling all the second ground layers 235 to be connected in parallel through the second external electrode 232.

[0086] Please refer to Figures 11 to 12 Furthermore, the second surface 2372 includes a first side surface 2372a, a second side surface 2372b, a third side surface 2372c, and a fourth side surface 2372d. Among them, the first side surface 2372a is opposite to the second side surface 2372b, and the third side surface 2372c and the fourth side surface 2372d are opposite to each other.

[0087] In one implementation, such as Figure 11 As shown, the third external electrode 233 is disposed on the first side 2372a, and the first external electrode 231 and the second external electrode 232 are disposed on the second side 2372b.

[0088] In another implementation, such as Figure 12 As shown, the third external electrode 233 is disposed on the first side 2372a, the first external electrode 231 is disposed on the fourth side 2372d, and the second external electrode 232 is disposed on the third side 2372c.

[0089] Of course, in addition to the two implementation methods mentioned above, the relative positional relationship of the first external electrode 231, the second external electrode 232, and the third external electrode 233 can also be in other forms, which will not be described in detail here.

[0090] Generally, under the same voltage conditions, the more piezoelectric layers 237 are stacked, the greater the output power of the piezoelectric actuator 100. Therefore, by stacking multiple piezoelectric layers 237, the piezoelectric actuator 100 can have a larger output power. Depending on the driving requirements, the number of piezoelectric layers 237 can be, but is not limited to, 2, 3, 4, 5, 6, 7, 8, or 9. Several examples of different numbers of piezoelectric layers 237 are given below.

[0091] Please refer to Figure 13 In one embodiment, there are two piezoelectric layers 237 in the first preset direction F1 (Z-axis direction). In the illustrated piezoelectric actuator 100 structure, there is one signal layer 236, one first ground layer 234, and one second ground layer 235, and the signal layer 236 is disposed between the first ground layer 234 and the second ground layer 235.

[0092] Please refer to Figures 4 to 7 In another embodiment, the number of piezoelectric layers 237 in the first preset direction F1 (Z-axis direction) is 3. In the illustrated piezoelectric actuator 100 structure, the number of signal layers 236 in the first preset direction F1 is 2, and the number of the first ground layer 234 and the second ground layer 235 is 1 each.

[0093] Please refer to Figure 14 In another embodiment, the number of piezoelectric layers 237 in the first preset direction F1 (Z-axis direction) is four. In the illustrated piezoelectric actuator 100 structure, the number of signal layers 236 in the first preset direction F1 is two, the number of first ground layers 234 in the first preset direction F1 is two, and the number of second ground layers 235 is one. It can be understood that in Figure 14 In this process, different arrangement structures can be formed by swapping the positions of any one of the first grounding layers 234 and the second grounding layer 235.

[0094] It should be noted that in the structure of the piezoelectric actuator 100, the number of the first ground layer 234 and the second ground layer 235 can be the same or different, and the number of the first ground layer 234 and the second ground layer 235 can be multiple or one. The following is an example of the case where there are multiple first ground layers 234 and multiple second ground layers 235.

[0095] Please refer to Figure 15 The piezoelectric body 23 is divided into a first region A1 and a second region A2 along the first preset direction F1 (Z-axis direction). There are multiple first grounding layers 234, second grounding layers 235, and signal layers 236, and the specific number can be 2, 3, 4, 5, etc.

[0096] Multiple signal layers 236 are simultaneously disposed in the first region A1 and the second region A2, and all signal layers 236 are connected in parallel through the third external electrode 233.

[0097] Multiple first ground layers 234 are disposed in the first region A1, and the first ground layers 234 and signal layers 236 are disposed alternately. That is, in the first region A1, a signal layer 236 is disposed between two adjacent first ground layers 234, and a first ground layer 234 is disposed between two adjacent signal layers 236. Furthermore, all the first ground layers 234 are connected in parallel through the first external electrode 231.

[0098] Multiple second ground layers 235 are disposed in the second region A2, and the second ground layers 235 and signal layers 236 are disposed alternately. That is, in the second region A2, a signal layer 236 is disposed between two adjacent second ground layers 235, and a second ground layer 235 is disposed between two adjacent signal layers 236. Furthermore, all the second ground layers 235 are connected in parallel through the second external electrode 232.

[0099] In this embodiment, each external electrode is electrically connected to each internal electrode, forming a parallel structure of corresponding internal electrodes in different layers on the circuit. Assuming the number of piezoelectric layers 237 is n, applying a voltage U will enable the piezoelectric actuator 100 to achieve a driving effect of n*U voltage. Furthermore, a first ground layer 234 is disposed in the first region A1, and a second ground layer 235 is disposed in the second region A2. The polarization direction of the first region A1 and the polarization direction of the second region A2 can be the same or different. When the polarization directions of the first region A1 and the second region A2 are different, the piezoelectric actuator 100 has a larger vibration amplitude, thereby achieving a greater driving force and driving speed.

[0100] Below Figure 15 Based on the structure shown, the polarization scheme of the piezoelectric actuator 100 is further explained.

[0101] Please refer to Figure 15 Each signal layer 236 includes a first signal electrode 2361 and a second signal electrode 2362, which are spaced apart. Figure 15 In this embodiment, the first signal electrode 2361 and the second signal electrode 2362 are arranged along the X-axis. In other embodiments, they may also be arranged along the Y-axis or in other directions inclined to the X-axis and Y-axis, which is not limited here.

[0102] Using the position between the first signal electrode 2361 and the second signal electrode 2362 as the boundary, the first region A1 is divided into a first sub-region A11 and a second sub-region A12, and the second region A2 is divided into a third sub-region A21 and a fourth sub-region A22. That is, after the region is divided, the first signal electrode 2361 is located within the first sub-region A11 and the third sub-region A21, and the second signal electrode 2362 is located within the second sub-region A12 and the fourth sub-region A22.

[0103] The third external electrode 233 includes a first sub-electrode 2331 and a second sub-electrode 2332. The first sub-electrode 2331 is electrically connected to all the first signal electrodes 2361 located in the first sub-region A11 and the third sub-region A21, so that the first signal electrodes 2361 of each layer are connected in parallel. The second sub-electrode 2332 is electrically connected to all the second signal electrodes 2362 located in the second sub-region A12 and the fourth sub-region A22, so that the second signal electrodes 2362 of each layer are connected in parallel.

[0104] In the first sub-region A11, since all the first signal electrodes 2361 are electrically connected to the first sub-electrode 2331 and all the first ground layers 234 are electrically connected to the first external electrode 231, all the piezoelectric layers 237 in the first sub-region A11 have the same polarization direction.

[0105] In the second sub-region A12, since all the second signal electrodes 2362 are electrically connected to the second sub-electrode 2332 and all the first ground layers 234 are electrically connected to the first external electrode 231, all the piezoelectric layers 237 in the second sub-region A12 have the same polarization direction.

[0106] In the third sub-region A21, since all the first signal electrodes 2361 are electrically connected to the first sub-electrode 2331 and all the second ground layers 235 are electrically connected to the second external electrode 232, all the piezoelectric layers 237 in the third sub-region A21 have the same polarization direction.

[0107] In the fourth sub-region A22, since all the second signal electrodes 2362 are electrically connected to the second sub-electrode 2332 and all the second ground layers 235 are electrically connected to the second external electrode 232, all the piezoelectric layers 237 in the fourth sub-region A22 have the same polarization direction.

[0108] It is understandable that, through the above configuration, the first sub-region A11, the second sub-region A12, the third sub-region A21, and the fourth sub-region A22 can be regarded as independent of each other. Therefore, the polarization directions of the four regions, the first sub-region A11, the second sub-region A12, the third sub-region A21, and the fourth sub-region A22, can be the same or different, so that the piezoelectric actuator 100 has multiple polarization forms.

[0109] The following is about Figure 15 Several possible polarization configurations of the piezoelectric actuator 100 are illustrated.

[0110] Please refer to Figure 15 and Figure 16 The first polarization configuration of the piezoelectric region is as follows: In the first sub-region A11, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 to the first signal electrode 2361. In the second sub-region A12, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 to the second signal electrode 2362. In the third sub-region A21, the polarization direction of the piezoelectric layer 237 is from the first signal electrode 2361 to the second ground layer 235. In the fourth sub-region A22, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 to the second ground layer 235.

[0111] Please refer to Figure 17 and Figure 18 The second polarization configuration of the piezoelectric region is as follows: In the first sub-region A11, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 to the first signal electrode 2361. In the second sub-region A12, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 to the first ground layer 234. In the third sub-region A21, the polarization direction of the piezoelectric layer 237 is from the first signal electrode 2361 to the second ground layer 235. In the fourth sub-region A22, the polarization direction of the piezoelectric layer 237 is from the second ground layer 235 to the second signal electrode 2362.

[0112] Please refer to Figure 19 and Figure 20 The third polarization configuration of the piezoelectric region is as follows: In the first sub-region A11, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 to the first signal electrode 2361. In the second sub-region A12, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 to the first ground layer 234. In the third sub-region A21, the polarization direction of the piezoelectric layer 237 is from the second ground layer 235 to the first signal electrode 2361. In the fourth sub-region A22, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 to the second ground layer 235.

[0113] Please refer to Figure 21 and Figure 22 The fourth polarization configuration of the piezoelectric region is as follows: In the first sub-region A11, the polarization direction of the piezoelectric layer 237 is from the first signal electrode 2361 to the first ground layer 234. In the second sub-region A12, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 to the second signal electrode 2362. In the third sub-region A21, the polarization direction of the piezoelectric layer 237 is from the second ground layer 235 to the first signal electrode 2361. In the fourth sub-region A22, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 to the second ground layer 235.

[0114] Please refer to Figure 23 This application also provides a piezoelectric motor 200, which includes a carrier 201, a mover 202, and a piezoelectric actuator 100 as described in any of the above embodiments. The piezoelectric actuator 100 can also be referred to as a stator. The carrier 201 can be a protective shell for storage and protection. The piezoelectric actuator 100 is connected to (e.g., bonded or welded) the carrier 201; the specific connection method is related to the structural and modal design and is not limited here. The mover 202 is movably connected to the carrier 201. The friction head 10 of the piezoelectric actuator 100 abuts against the mover 202 to drive the mover 202 to move along a second preset direction F2.

[0115] The piezoelectric motor 200 may also include a rolling element 203, which may be a spherical ball or a cylindrical roller. The rolling element 203 is disposed between the mover 202 and the carrier 201 so that the mover 202 can move relative to the carrier 201.

[0116] When a suitable AC drive signal is applied to the piezoelectric actuator 100, it can generate high-frequency micro-amplitude vibrations, thereby converting its own micro-motion into macro-motion of the mover 202 through friction. The motion output by the mover 202 can be linear motion or rotational motion; here, only linear motion is illustrated.

[0117] Please refer to Figure 24 and Figure 25 This application also provides a camera module 301, which includes a lens 3011, a photosensitive element 3012, and a piezoelectric actuator 100 as described in any of the above embodiments.

[0118] The lens 3011 collects light from the subject and focuses it onto the photosensitive element 3012. The photosensitive element 3012, also known as a photosensitive chip, image sensor, or sensor, receives light passing through the lens 3011 and converts the light signal into an electrical signal. The photosensitive element 3012 can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) device.

[0119] The piezoelectric actuator 100 can be directly or indirectly connected to the lens 3011 to drive the lens 3011 to move during the operation of the camera module 301, so as to realize the AF (autofocus) function and / or OIS (optical image stabilization) function of the camera module 301.

[0120] In one embodiment, the piezoelectric actuator 100 can drive the lens 3011 to move relative to the photosensitive element 3012 along the extension direction of the optical axis G, so as to realize the AF (autofocus) function of the camera module 301, such as Figure 24 As shown.

[0121] In another embodiment, the piezoelectric actuator 100 can drive the lens 3011 to move relative to the photosensitive element 3012 in a direction perpendicular to the optical axis G, thereby realizing the OIS (optical image stabilization) function of the camera module 301, such as... Figure 25 As shown.

[0122] In another embodiment, a plurality of piezoelectric actuators 100 are disposed in the camera module 301, wherein at least one piezoelectric actuator 100 is used to implement the AF (autofocus) function of the camera module 301, and at least one piezoelectric actuator 100 is used to implement the OIS (optical image stabilization) function of the camera module 301.

[0123] Of course, in other embodiments, the piezoelectric actuator 100 can also be used to drive the photosensitive element 3012 to move relative to the lens 3011 in order to realize the AF (autofocus) function and / or OIS (optical image stabilization) function of the camera module 301.

[0124] Please refer to Figure 26 This application also provides an electronic device 300, which includes a device body 302 and a camera module 301 described in the above embodiments, wherein the camera module 301 is mounted on the device body 302.

[0125] The electronic device 300 can be a mobile phone, tablet computer, laptop computer, wearable device (such as a smartwatch, bracelet, VR device, etc.), television set, in-vehicle device, e-reader, etc. It should be noted that this application embodiment only uses a mobile phone as an example for illustration.

[0126] The device body 302 refers to the main body of the electronic device 300. The main body includes functional components that realize the main functions of the electronic device 300 and mechanical structures that protect and support these functional components. Taking a mobile phone as an example, the device body 302 may include a display screen, a mid-frame, and a battery cover. The display screen and the battery cover are both connected to the mid-frame and are respectively located on opposite sides of the mid-frame.

[0127] The camera module 301 can be either a straight-through camera or a periscope camera. A periscope camera refers to a camera whose optical axis G is bent (e.g., bent at 90°), while a straight-through camera refers to a camera whose optical axis G is a straight line without bending. Depending on the actual needs, the light-transmitting window of the camera module 301 can be located anywhere on the electronic device 300. Taking a mobile phone as an example, the light-transmitting window of the camera module 301 can be located on the front, back, or side of the phone. The front refers to the side of the phone with the display screen; the back refers to the side of the phone with the battery cover; and the side refers to the circumference of the phone's frame. It is understood that the definitions of "front," "back," and "side" may differ depending on the type of electronic device 300; other types of electronic devices 300 will not be listed here.

[0128] In related technologies, the camera module 301 uses an electromagnetic motor to drive the lens 3011 to achieve AF (autofocus) and OIS (optical image stabilization) functions. However, the magnetic field generated by the electromagnetic motor will interfere with other electronic components within the electronic device 300. In this application, the camera module 301 uses a piezoelectric actuator 100, which does not generate a magnetic field during operation, thereby avoiding magnetic field interference problems.

[0129] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application, and such improvements and refinements are also considered to be within the protection scope of this application.

Claims

1. A piezoelectric actuator, characterized by, The piezoelectric actuator includes: a friction head and a stacked piezoelectric element, wherein the friction head is connected to the stacked piezoelectric element; The stacked piezoelectric element includes a piezoelectric body, which includes a first region along a first preset direction; in the first region, the piezoelectric body includes a first external electrode, a third external electrode, a first ground layer, a signal layer, and multiple piezoelectric layers. Multiple piezoelectric layers are arranged sequentially at intervals along a first preset direction. Each piezoelectric layer has two opposing first surfaces and a second surface bent and connected to the first surfaces. The relative directions of the two first surfaces are parallel to the first preset direction. The first ground layer and the signal layer are respectively connected to different first surfaces, so that the electrodes on opposite sides of the same piezoelectric layer are the signal layer and the first ground layer, respectively; Both the first external electrode and the third external electrode are connected to the second surface, with the first external electrode electrically connected to the first ground layer and the third external electrode electrically connected to the signal layer.

2. The piezoelectric actuator of claim 1, wherein, The piezoelectric body further includes a second region along the first preset direction; in the second region, the piezoelectric body includes a second external electrode, a third external electrode, a second ground layer, a signal layer, and multiple piezoelectric layers; The second ground layer and the signal layer are respectively connected to different first surfaces, so that the electrodes on opposite sides of the same piezoelectric layer are the signal layer and the second ground layer, respectively; Both the second external electrode and the third external electrode are connected to the second surface, and the second external electrode is electrically connected to the second grounding layer.

3. The piezoelectric actuator of claim 1 or 2, wherein Each of the signal layers includes multiple signal electrodes, which are arranged at intervals. The third external electrode includes multiple sub-electrodes, and different sub-electrodes are electrically connected to different signal electrodes.

4. The piezoelectric actuator of claim 1 or 2, wherein In the first region, there are multiple first ground layers and multiple signal layers; Multiple signal layers are simultaneously disposed in the first region, and all of the signal layers are connected in parallel through the third external electrode; Multiple first ground layers are disposed in the first region and alternate with the signal layer, and all the first ground layers are connected in parallel through the first external electrode.

5. The piezoelectric actuator of claim 2, wherein, In the second region, there are multiple second ground layers and multiple signal layers; Multiple signal layers are simultaneously disposed in the second region, and all of the signal layers are connected in parallel through the third external electrode; Multiple second ground layers are disposed in the second region and alternate with the signal layer, and all the second ground layers are connected in parallel through the second external electrode.

6. The piezoelectric actuator of claim 2, wherein, Each signal layer includes a first signal electrode and a second signal electrode, which are spaced apart. The first region is divided into a first sub-region and a second sub-region by the position between the first signal electrode and the second signal electrode. The third external electrode includes a first sub-electrode and a second sub-electrode, wherein the first sub-electrode is electrically connected to all the first signal electrodes located in the first sub-region, and the second sub-electrode is electrically connected to all the second signal electrodes located in the second sub-region.

7. The piezoelectric actuator of claim 6, wherein, The second region is divided into a third sub-region and a fourth sub-region, with the position between the first signal electrode and the second signal electrode as the boundary; the first sub-electrode is electrically connected to all the first signal electrodes located in the third sub-region, and the second sub-electrode is electrically connected to all the second signal electrodes located in the fourth sub-region.

8. The piezoelectric actuator as claimed in claim 6, characterized in that, In the first sub-region, the polarization direction of the piezoelectric layer is the direction from the first ground layer to the first signal electrode; in the second sub-region, the polarization direction of the piezoelectric layer is the direction from the first ground layer to the second signal electrode; or... In the first sub-region, the polarization direction of the piezoelectric layer is the direction from the first signal electrode to the first ground layer; and in the second sub-region, the polarization direction of the piezoelectric layer is the direction from the first signal electrode to the first ground layer.

9. The piezoelectric actuator as claimed in claim 7, characterized in that, Within the third sub-region, the polarization direction of the piezoelectric layer is the direction from the first signal electrode to the second ground layer; Within the fourth sub-region, the polarization direction of the piezoelectric layer is the direction from the second signal electrode to the second ground layer.

10. The piezoelectric actuator as claimed in claim 6, characterized in that, Within the first sub-region, the polarization direction of the piezoelectric layer is the direction from the first ground layer to the first signal electrode; Within the second sub-region, the polarization direction of the piezoelectric layer is the direction in which the second signal electrode points to the first ground layer.

11. The piezoelectric actuator as claimed in claim 7, characterized in that, Within the third sub-region, the polarization direction of the piezoelectric layer is the direction from the first signal electrode to the second ground layer; Within the fourth sub-region, the polarization direction of the piezoelectric layer is the direction from the second ground layer to the second signal electrode.

12. The piezoelectric actuator as claimed in claim 6, characterized in that, Within the first sub-region, the polarization direction of the piezoelectric layer is the direction from the first ground layer to the first signal electrode; Within the second sub-region, the polarization direction of the piezoelectric layer is the direction in which the second signal electrode points to the first ground layer.

13. The piezoelectric actuator as claimed in claim 7, characterized in that, Within the third sub-region, the polarization direction of the piezoelectric layer is the direction from the second ground layer to the first signal electrode; Within the fourth sub-region, the polarization direction of the piezoelectric layer is the direction from the second signal electrode to the second ground layer.

14. The piezoelectric actuator as claimed in claim 6, characterized in that, Within the first sub-region, the polarization direction of the piezoelectric layer is the direction from the first signal electrode to the first ground layer; Within the second sub-region, the polarization direction of the piezoelectric layer is the direction from the first ground layer to the second signal electrode.

15. The piezoelectric actuator as claimed in claim 7, characterized in that, Within the third sub-region, the polarization direction of the piezoelectric layer is the direction from the second ground layer to the first signal electrode; Within the fourth sub-region, the polarization direction of the piezoelectric layer is the direction from the second signal electrode to the second ground layer.

16. The piezoelectric actuator of any one of claims 2, 5-15, wherein, The first grounding layer includes a first body portion and a first lead portion. The first body portion is spaced at the periphery of the first surface of the piezoelectric layer. One end of the first lead portion is connected to the first body portion, and the other end of the first lead portion is connected to the first external electrode.

17. The piezoelectric actuator as claimed in claim 16, characterized in that, The second grounding layer includes a second body portion and a second lead portion. The second body portion is spaced at the periphery of the first surface of the piezoelectric layer. One end of the second lead portion is connected to the second body portion, and the other end of the second lead portion is connected to the second external electrode. The projections of the first lead-out portion and the second lead-out portion on the piezoelectric layer do not overlap.

18. The piezoelectric actuator as claimed in claim 17, characterized in that, The first body portion has a first end and a second end that are far apart from each other, the first end being adjacent to the second lead-out portion relative to the second end, and the first lead-out portion being connected to the second end; the second body portion has a third end and a fourth end that are far apart from each other, the fourth end being adjacent to the first lead-out portion relative to the third end, and the second lead-out portion being connected to the third end.

19. The piezoelectric actuator according to any one of claims 2, 5 to 15, 17, and 18, characterized in that, The edge of at least one of the first ground layer, the second ground layer, and the signal layer is flush with the second surface.

20. The piezoelectric actuator according to any one of claims 1, 2, 5 to 15, 17, and 18, characterized in that, The stacked piezoelectric component further includes a first protective layer and a second protective layer, which are respectively disposed at opposite ends of the piezoelectric body along the first preset direction.

21. A piezoelectric motor, characterized in that, The piezoelectric motor includes a carrier, a mover, and a piezoelectric actuator as described in any one of claims 1 to 20, wherein the piezoelectric actuator is connected to the carrier, the mover is movably connected to the carrier, and the piezoelectric actuator abuts against the mover to drive the mover to move.

22. A camera module, characterized in that, The camera module includes a piezoelectric actuator as described in any one of claims 1 to 20.

23. An electronic device, characterized in that, The electronic device includes a device body and a camera module as described in claim 22, wherein the camera module is mounted on the device body.

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