Piezoelectric driver, piezoelectric driving module and electronic equipment

Abstract

The invention relates to a piezoelectric driver, a piezoelectric driving module and electronic equipment. The piezoelectric actuator includes a piezoelectric body and a friction layer. At least part of the piezoelectric main body can be applied with voltage to generate deformation motion. The friction layer is arranged on the piezoelectric main body and used for being in contact with a driven part, the surface friction coefficient of the friction layer is larger than that of the piezoelectric main body, and the hardness of the friction layer is larger than that of the piezoelectric main body. According to the piezoelectric actuator, the requirements for friction force driving and wear resistance are met, meanwhile, the size of the piezoelectric actuator is reduced, and miniaturization design of the piezoelectric actuator is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of piezoelectric drive, and particularly to a piezoelectric driver, a piezoelectric drive module, and an electronic device. Background Art

[0002] A piezoelectric motor is a piezoelectric device that utilizes the inverse piezoelectric effect of a piezoelectric material (the inverse piezoelectric effect means that when an electric field is applied in the polarization direction of the piezoelectric material, the piezoelectric material generates mechanical deformation in a certain direction, and when the electric field is removed, the deformation of the piezoelectric material also disappears), excites the piezoelectric driver (i.e., the stator) to have a small-amplitude vibration within a certain frequency, and through the friction effect, converts the small-amplitude vibration of the stator into the macroscopic linear or rotational motion of the rotor. For a traditional piezoelectric motor, in order to enable the small-amplitude vibration generated by the piezoelectric driver to act on the rotor, it usually leads to an increase in the occupied space of the piezoelectric driver, which is not conducive to miniaturization design. Summary of the Invention

[0003] Embodiments of the present application provide a piezoelectric driver, a piezoelectric drive module, and an electronic device to compress the occupied space of the piezoelectric driver.

[0004] A piezoelectric driver includes:

[0005] A piezoelectric main body, at least a part of which can be applied with a voltage to generate a deformation motion; and,

[0006] A friction layer, provided on the piezoelectric main body and used to contact a driven member, the surface friction coefficient of the friction layer is greater than the surface friction coefficient of the piezoelectric main body, and the hardness of the friction layer is greater than the hardness of the piezoelectric main body.

[0007] A piezoelectric drive module includes a carrier, a driven member, and the piezoelectric driver as described above. The piezoelectric driver is provided on the carrier, and the side of the friction layer of the piezoelectric driver facing away from the piezoelectric main body contacts the driven member.

[0008] In one embodiment, the piezoelectric drive module is a piezoelectric motor, the driven member is a rotor, and the driven member is movably connected to the carrier.

[0009] In one embodiment, the piezoelectric drive module is a camera module, the driven member is a lens or an image sensor, and the driven member is provided on the carrier.

[0010] An electronic device includes the piezoelectric drive module as described in any of the above embodiments.

[0011] In the above piezoelectric actuator, a friction layer is provided on the piezoelectric body to contact the driven member. When a voltage is applied to the piezoelectric body to cause a deformation movement, the driven member can be driven to move by means of the frictional force between the friction layer and the driven member. The surface friction coefficient of the friction layer is greater than that of the piezoelectric body, and the hardness of the friction layer is greater than that of the piezoelectric body, which can meet the requirements of frictional force driving and wear resistance. At the same time, by means of the layer structure provided on the piezoelectric body to perform frictional driving on the driven member, the piezoelectric actuator does not need to be provided with convex structures such as friction heads, which is beneficial to compressing the volume of the piezoelectric actuator and is beneficial to the miniaturized design of the piezoelectric actuator. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0013] Figure 1 Schematic diagram of a piezoelectric actuator provided by some embodiments of the present application.

[0014] Figure 2 is Figure 1 Exploded view of the piezoelectric actuator shown.

[0015] Figure 3 Schematic diagram of a piezoelectric body provided by some embodiments of the present application.

[0016] Figure 4 is Figure 3 Schematic diagram of a polarization method of the piezoelectric body shown.

[0017] Figure 5 is Figure 3 Schematic diagram of another polarization method of the piezoelectric body shown.

[0018] Figure 6 is Figure 3 Schematic diagram of yet another polarization method of the piezoelectric body shown.

[0019] Figure 7 is Figure 3 Schematic diagram of yet another polarization method of the piezoelectric body shown.

[0020] Figure 8 Exploded view of the partial stack of the piezoelectric body provided by some embodiments of the present application.

[0021] Figure 9 Schematic diagram of the structure of the first grounding layer provided by some embodiments of the present application.

[0022] Figure 10 Schematic diagram of the second grounding layer provided for some embodiments of the present application.

[0023] Figure 11 A diagram showing a relative positional relationship of the first outer electrode, the second outer electrode, and the third outer electrode provided for some embodiments of the present application.

[0024] Figure 12 Another diagram showing a relative positional relationship of the first outer electrode, the second outer electrode, and the third outer electrode provided for some embodiments of the present application.

[0025] Figure 13 Schematic diagram of the piezoelectric body provided for some other embodiments of the present application.

[0026] Figure 14 Schematic diagram of the piezoelectric body provided for some other embodiments of the present application.

[0027] Figure 15 Schematic diagram of the piezoelectric body provided for some other embodiments of the present application.

[0028] Figure 16 For Figure 15 Schematic diagram of the polarization mode shown.

[0029] Figure 17 Schematic diagram of the piezoelectric body provided for some other embodiments of the present application.

[0030] Figure 18 For Figure 17 Schematic diagram of the polarization mode shown.

[0031] Figure 19 Schematic diagram of the piezoelectric body provided for some other embodiments of the present application.

[0032] Figure 20 For Figure 19 Schematic diagram of the polarization mode shown.

[0033] Figure 21 Schematic diagram of the piezoelectric body provided for some other embodiments of the present application.

[0034] Figure 22 For Figure 21 Schematic diagram of the polarization mode shown.

[0035] Figure 23 Schematic diagram of the piezoelectric drive module provided for embodiments of the present application.

[0036] Figure 24 Schematic diagram of the piezoelectric drive module provided for some other embodiments of the present application.

[0037] Figure 25 ForFigure 23 Schematic diagram of another angle of the piezoelectric drive module shown.

[0038] Figure 26 is Figure 24 Explosion schematic diagram of the piezoelectric drive module shown.

[0039] Figure 27 is Figure 24 Cross-sectional schematic diagram of the piezoelectric drive module shown.

[0040] Figure 28 Schematic diagram of the piezoelectric drive module provided by some other embodiments of the present application.

[0041] Figure 29 Schematic diagram of the piezoelectric drive module provided by some further embodiments of the present application.

[0042] Figure 30 Schematic diagram of the piezoelectric drive module provided by some further embodiments of the present application.

[0043] Figure 31 Schematic diagram of the electronic device provided by some embodiments of the present application. Detailed implementation manners

[0044] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0045] As used herein, an "electronic device" refers to a device that can receive and / or send communication signals and includes, but is not limited to, a device connected via any one or several of the following connection methods:

[0046] (1) Via a wired connection method, such as via a Public Switched Telephone Network (PSTN), Digital Subscriber Line (DSL), digital cable, or direct cable connection;

[0047] (2) Via a wireless interface method, such as a cellular network, Wireless Local Area Network (WLAN), digital television network such as a DVB-H network, satellite network, or AM-FM broadcast transmitter.

[0048] An electronic device configured to communicate via a wireless interface may be referred to as a "mobile terminal". Examples of mobile terminals include, but are not limited to, the following electronic devices:

[0049] (1) A satellite phone or a cellular phone;

[0050] (2) A Personal Communications System (PCS) terminal that can combine cellular radiotelephone with data processing, fax, and data communication capabilities;

[0051] (3) A radiotelephone, a pager, Internet / intranet access, a web browser, a notepad, a calendar, a Personal Digital Assistant (PDA) equipped with a Global Positioning System (GPS) receiver;

[0052] (4) Conventional laptop and / or palm-sized receivers;

[0053] (5) Conventional laptop and / or palm-sized radiotelephone transceivers, etc.

[0054] Please refer to Figure 1 , this application provides a piezoelectric actuator 100, which can also be referred to as a stacked piezoelectric actuator, a piezoelectric actuator, a stator, etc. The piezoelectric actuator 100 is used to generate high-frequency micro-amplitude vibrations to convert its microscopic motion into the macroscopic motion of the driven member 202. The motion type of the piezoelectric actuator 100 can be but is not limited to elliptical motion, oblique motion, etc. In this application, the motion type of the piezoelectric actuator 100 is collectively referred to as deformation motion, and the elliptical motion will be taken as an example for illustration hereinafter.

[0055] For the convenience of subsequent description and understanding of the drawings, a XYZ space rectangular coordinate system is defined from the perspective shown in Figure 1 . Among them, 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 here for the following description of the XYZ coordinate system.

[0056] The piezoelectric actuator 100 includes a stacked piezoelectric member 20 and a friction layer 24, and the friction layer 24 is disposed on the stacked piezoelectric member 20. At least part of the stacked piezoelectric member 20 can be applied with a voltage to generate deformation motion, and the function of the stacked piezoelectric member 20 is to generate high-frequency micro-amplitude vibrations, thereby driving the friction layer 24 to deform. The friction layer 24 is used to contact the driven member 202 (shown in Figure 23 ), or contact the friction structure on the driven member 202. The friction layer 24 is used to directly or indirectly drive the driven member 202 through friction to convert the microscopic motion of the stacked piezoelectric member 20 into the macroscopic motion of the driven member 202 and ensure reliability.

[0057] Please refer to Figure 1 and Figure 2 In some embodiments, the laminated piezoelectric element 20 is a laminated structure, which includes a piezoelectric main 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 on two opposite sides of the piezoelectric main body 23 along a first preset direction (Z-axis direction), that is, the first protective layer 21, the piezoelectric main body 23, and the second protective layer 22 are stacked in sequence. At least a part of the piezoelectric main body 23 can be applied with a voltage to generate a deformation motion, and then drive the first protective layer 21, the second protective layer 22, and the friction layer 24 to deform. The first protective layer 21 and the second protective layer 22 can protect the circuit in the piezoelectric main body 23 and isolate signals, so that the piezoelectric main body 23 can work normally.

[0058] It should be noted that when the laminated piezoelectric element 20 is provided with the first protective layer 21 and the second protective layer 22, the friction layer 24 can be formed on or disposed on the side of the first protective layer 21 facing away from the piezoelectric main body 23, or can be connected to the piezoelectric main body 23. The first protective layer 21 and the second protective layer 22 in the laminated piezoelectric element 20 can also be omitted, then the friction layer 24 is connected to the piezoelectric main body 23, which is not limited herein.

[0059] The surface friction coefficient of the friction layer 24 is greater than the surface friction coefficient of the piezoelectric main body 23, and the hardness of the friction layer 24 is greater than the hardness of the piezoelectric main body 23.

[0060] In the above piezoelectric actuator 100, the friction layer 24 is disposed on the piezoelectric main body 23 to contact the driven member 202. When the piezoelectric main body 23 is applied with a voltage to generate a deformation motion, it can drive the driven member 202 to move by means of the friction force between the friction layer 24 and the driven member 202. The surface friction coefficient of the friction layer 24 is greater than the surface friction coefficient of the piezoelectric main body 23, and the hardness of the friction layer 24 is greater than the hardness of the piezoelectric main body 23, which can meet the requirements of friction force driving and wear resistance. At the same time, by using the layer structure provided on the piezoelectric main body 23 to perform friction driving on the driven member 202, the piezoelectric actuator 100 does not need to be provided with convex structures such as friction heads. The friction layer 24, as a layer structure, has a size in the thickness direction (Z-axis direction) much smaller than that of convex structures such as friction heads, which is beneficial to compressing the volume of the piezoelectric actuator 100, and thus beneficial to the miniaturization design of the piezoelectric actuator 100.

[0061] In some embodiments, the friction layer 24 is formed by hardening treatment. For example, the friction layer 24 is formed by hardening treatment of a partial layer structure of the piezoelectric body 23 located on the outermost side, or the friction layer 24 is formed by hardening treatment of a partial layer structure of the first protective layer 21 away from the piezoelectric body 23. Thus, it is equivalent to forming the friction layer 24 by hardening treatment of a partial layer structure of the laminated piezoelectric element 20, so that the setting of the friction layer 24 will not increase the thickness dimension of the laminated piezoelectric element 20. That is to say, the overall thickness dimension of the laminated piezoelectric element 20 and the friction layer 24 is equivalent to the thickness dimension of the laminated piezoelectric element in a conventional piezoelectric actuator provided with a friction head on the laminated piezoelectric element, omitting the occupied space of the friction head in the thickness direction, and effectively reducing the overall thickness dimension of the piezoelectric actuator 100 while setting the friction layer 24. The hardening treatment involved in the present application includes but is not limited to carburizing treatment, nitriding treatment or metal infiltration treatment, as long as the friction layer 24 formed by hardening treatment can meet the requirements of surface friction coefficient and hardness and can convert the deformation movement into the movement of the driven member 202 through friction.

[0062] In other embodiments, the friction layer 24 is a surface coating provided on the laminated piezoelectric element 20, for example, provided on the piezoelectric body 23 or on the side of the first protective layer 21 facing away from the piezoelectric body 23. Exemplarily, the friction layer 24 includes but is not limited to a metal film layer, a ceramic film layer or a polymer material layer (such as polytetrafluoroethylene, hard rubber, etc.). Specifically, the friction layer 24 can be a metal film layer prepared by processes such as physical vapor deposition (PVD), chemical vapor deposition (CVD), electroplating, electroless plating, screen printing, etc., or a ceramic film layer prepared by processes such as sol-gel method, CVD, atomic layer deposition (ALD), plasma spraying, etc., or a polymer material layer prepared by processes such as spin coating, spraying, CVD, hot pressing, etc. It can be seen that when the friction layer 24 is a surface coating, the thickness dimension of the friction layer 24 is much smaller than the thickness dimension of conventional structures such as friction heads, which is also beneficial to reducing the overall volume of the piezoelectric actuator 100.

[0063] In some embodiments, the friction layer 24 is laid flat on one surface of the piezoelectric body 23, that is to say, the projection of the friction layer 24 on the piezoelectric body 23 covers one surface of the piezoelectric body 23 in the Z-axis direction. The friction layer 24 can be directly or indirectly laid flat on the piezoelectric body 23. For example, when the laminated piezoelectric element 20 is provided with a first protective layer 21 and a second protective layer 22, the friction layer 24 can be provided on the first protective layer 21, that is, indirectly laid flat on the piezoelectric body 23. When the laminated piezoelectric element 20 does not have the first protective layer 21, the friction layer 24 can also be directly provided on the piezoelectric body 23.

[0064] The shape of the friction layer 24 is not limited. When the friction layer 24 is laid flat on the piezoelectric body 23, the piezoelectric body 23 can be generally in the shape of a cuboid, and the friction layer 24 can be square extending along the XY plane. Of course, the projection of the friction layer 24 on the piezoelectric body 23 can also only cover a part of one surface of the piezoelectric body 23 in the Z-axis direction, and the cross-section of the friction layer 24 includes but is not limited to any applicable shapes such as circular and square.

[0065] Reference Figure 1 and Figure 2 As shown, in some embodiments, on the side of the friction layer 24 facing away from the piezoelectric body 23, there are periodically arranged textures or non-periodically arranged patterns 241, and the textures or patterns 241 can cover the entire surface of the side of the friction layer 24 facing away from the piezoelectric body 23. The textures provided on the friction layer 24 include but are not limited to columnar structures, corrugated structures, grid-like structures, or spiral structures, etc. The patterns 241 provided on the friction layer 24 include but are not limited to random granular structures, irregular grooves, random patterns 241, or protrusions of different shapes, etc. Setting the textures or patterns 241 on the friction layer 24 to contact the driven member 202 is beneficial to increasing the contact area between the friction layer 24 and the driven member 202, enhancing the friction performance between the friction layer 24 and the driven member 202, and thus being beneficial to improving the driving performance of the piezoelectric actuator 100 on the driven member 202.

[0066] In some embodiments, on the basis that the friction layer 24 meets the requirements of surface friction coefficient and hardness, the surface of the friction layer 24 facing away from the piezoelectric body 23 can also be lubricated, for example, setting media such as lubricants on the friction layer 24 to reduce the noise and debris generated during the friction between the friction layer 24 and the driven member 202. Then, the setting of the textures and patterns 241 is also beneficial to capturing and retaining media such as lubricants, and prolonging the service life of the piezoelectric actuator 100.

[0067] The specific setting of the piezoelectric body 23 is not limited, as long as it can generate a deformation motion so that the friction layer 24 can drive the driven member 202 to move by means of the frictional force between the friction layer 24 and the driven member 202. Please refer to Figure 3 and Figure 4 , in some embodiments, the piezoelectric body 23 includes: a first outer electrode 231, a second outer electrode 232, a third outer electrode 233, a first ground layer 234, a second ground layer 235, a signal layer 236, and a plurality of piezoelectric layers 237. Here, the "first outer electrode 231, second outer electrode 232, third outer electrode 233" are defined as outer electrodes, and the "first ground layer 234, second ground layer 235, signal layer 236" are defined as inner electrodes. For subsequent descriptions related to inner electrodes and outer electrodes, please refer to this.

[0068] A plurality of piezoelectric layers 237 (the number of piezoelectric layers 237 is greater than or equal to 2) are arranged at intervals in the Z-axis direction. Each piezoelectric layer 237 has two first surfaces 2371 facing away from each other and a second surface 2372 bent and connected to the first surface 2371 (see Figure 4 ). The second surface 2372 (see Figure 3 ). The relative directions of the two first surfaces 2371 are parallel to the Z-axis direction.

[0069] The piezoelectric layer 237 is a piezoelectric material, and the material of the piezoelectric layer 237 can be selected from 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.

[0070] The piezoelectric material has no polarization direction in its initial state and only exhibits polarization under specific conditions. After applying pressure or an electric field, the positive and negative charges in the piezoelectric material will rearrange, causing different polarities to form at the upper and lower ends of the piezoelectric material. This process is the polarization of the piezoelectric material.

[0071] The piezoelectric layer 237 can be in the shape of a rectangular sheet, that is, the projection shape of the piezoelectric layer 237 on the XY plane can be a rectangle. In other embodiments, the projection shape of the piezoelectric layer 237 on the XY plane can also be circular, elliptical, irregular, etc. This application only takes the rectangle as an example.

[0072] The number of the first ground layer 234, the second ground layer 235, and the signal layer 236 in the 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 Z-axis direction, and 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 the opposite sides of the same piezoelectric layer 237 are the signal layer 236 and the first ground layer 234 respectively, or the electrodes on the opposite sides of the same piezoelectric layer 237 are the signal layer 236 and the second ground layer 235 respectively.

[0073] The signal layer 236 is mainly used to load an AC drive signal during the operation of the piezoelectric actuator 100. The functions of the first ground layer 234 and the second ground layer 235 are to ground and load an AC drive signal during the operation of the piezoelectric actuator 100. The drive signal here can be waveforms such as square waves, sine waves, and sawtooth waves. The three inner electrodes of the first ground layer 234, the second ground layer 235, and the signal layer 236 can be made of conductive metal or a metal thin layer. The inner electrodes can be tightly bonded to the piezoelectric layer 237 by printing, coating, etc. For example, the signal layer 236 is formed on the first surface 2371 by screen printing conductive silver paste or conductive glue.

[0074] If the electrodes on the opposite sides of the piezoelectric layer 237 are the signal layer 236 and the first grounding layer 234 respectively, the signal layer 236 and the first grounding layer 234 are used to form a first electric field. That is, the signal layer 236 and the first grounding 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. The electrodes on the opposite sides of the piezoelectric layer 237 are the signal layer 236 and the second grounding layer 235 respectively. The signal layer 236 and the second grounding layer 235 are used to form a second electric field. That is, the signal layer 236 and the second grounding 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.

[0075] For the convenience of subsequent description, here, the "signal layer 236 and the first grounding layer 234" are collectively referred to as the "first polarization combination", and the piezoelectric layer 237 located between the "signal layer 236 and the first grounding layer 234" is called the "first piezoelectric layer"; the "signal layer 236 and the second grounding layer 235" are collectively referred to as the "second polarization combination", and the piezoelectric layer 237 located between the "signal layer 236 and the second grounding layer 235" is called the "second piezoelectric layer". For subsequent descriptions related to the first polarization combination, the second polarization combination, the first piezoelectric layer, and the second piezoelectric layer, please refer to this place.

[0076] 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 the first external electrode 231, the second external electrode 232, and the third external electrode 233 are spaced apart from each other to avoid electrical contact. The first external electrode 231, the second external electrode 232, and the third external electrode 233 can be made of conductive metal or a thin metal layer.

[0077] The first external electrode 231 is electrically connected to the first grounding layer 234. When the number of the first grounding layers 234 is multiple, the first external electrode 231 is electrically connected to all the first grounding layers 234 so that the first grounding layers 234 are connected in parallel.

[0078] The second external electrode 232 is electrically connected to the second grounding layer 235. When the number of the second grounding layers 235 is multiple, the second external electrode 232 is electrically connected to all the second grounding layers 235 so that the second grounding layers 235 are connected in parallel.

[0079] The third external electrode 233 is electrically connected to the signal layer 236. When the number of the signal layers 236 is multiple, the third external electrode 233 is electrically connected to all the signal layers 236 so that the signal layers 236 are connected in parallel.

[0080] The main function of each of the above external electrodes is to form a connection with the corresponding internal electrode, so that the drive signal is loaded onto the internal electrode. The first polarization combination and the second polarization combination can generate an appropriate electric field to polarize the piezoelectric layer 237 or drive the piezoelectric layer 237 to vibrate through the electric field.

[0081] In the piezoelectric actuator 100 provided in the present application, by applying an appropriate AC drive signal to the external electrode, the corresponding vibration mode can be excited in each piezoelectric layer 237. Under the cooperative vibration of multiple piezoelectric layers 237, the entire piezoelectric actuator 100 can present a corresponding motion form. The piezoelectric actuator 100 can estimate the frequency of the drive signal that can generate microscopic elliptical motion through size optimization and modal analysis. Among them, the elliptical motion can be achieved by means of a single mode, such as the B2 mode (second-order bending mode), and the elliptical motion can also be achieved by superimposing multiple modes, such as the L1B2 mode (first-order elongation mode + second-order bending mode), the B1B2 mode (first-order bending mode + second-order bending mode).

[0082] The piezoelectric actuator 100 provided in the present application needs to be polarized to have piezoelectric properties in order to obtain the required motion form, and the polarization of the piezoelectric actuator 100 is achieved by the electric field formed by the first polarization combination and the second polarization combination. It should be noted that the polarization direction of the polarized piezoelectric material is the direction of the electric field applied when polarizing the piezoelectric material.

[0083] In the present application, since the first grounding layer 234 is connected to the first external electrode 231 and the second grounding layer 235 is connected to the second external electrode 232, the first grounding layer 234 and the second grounding layer 235 are independent of each other. Since the first grounding layer 234 and the second grounding layer 235 are independent of each other, the electric potential of the first grounding layer 234 and the electric potential of the second grounding layer 235 can be the same or different, and further, the direction of the electric field formed by the first polarization combination (simply referred to as the first electric field) and the direction of the electric field formed by the second polarization combination (simply referred to as the second electric field) can be the same or different. Therefore, the polarization direction of the first piezoelectric layer (simply referred to as the first polarization direction) provided between the first polarization combinations and the polarization direction of the second piezoelectric layer (simply referred to as the second polarization direction) provided between the second polarization combinations can be the same or different.

[0084] Therefore, for the piezoelectric actuator 100 provided in the present application, its polarization scheme can adopt the following 4 types (as Figures 4 to 7 shown. It should be noted that in the relevant drawings of the present application, the direction indicated by the hollow arrow represents the polarization direction):

[0085] The first polarization scheme: The polarization direction of the first piezoelectric layer is the direction from the first grounding layer 234 towards the signal layer 236, and the polarization direction of the second piezoelectric layer is the direction from the second grounding layer 235 towards the signal layer 236, asFigure 4 as shown;

[0086] The second polarization scheme: The polarization direction of the first piezoelectric layer is the direction in which the signal layer 236 faces the first ground layer 234, and the polarization direction of the second piezoelectric layer is the direction in which the signal layer 236 faces the second ground layer 235, as Figure 5 shown;

[0087] The third polarization scheme: The polarization direction of the first piezoelectric layer is the direction in which the first ground layer 234 faces the signal layer 236, and the polarization direction of the second piezoelectric layer is the direction in which the signal layer 236 faces the second ground layer 235, as Figure 6 shown;

[0088] The fourth polarization scheme: The polarization direction of the first piezoelectric layer is the direction in which the signal layer 236 faces the first ground layer 234, and the polarization direction of the second piezoelectric layer is the direction in which the second ground layer 235 faces the signal layer 236, as Figure 7 shown.

[0089] In Figure 4 , since the polarization directions of both the first piezoelectric layer and the second piezoelectric layer are "the direction in which the ground layer faces the signal layer 236", the polarization directions of the first piezoelectric layer and the second piezoelectric layer are regarded as the same, that is, the polarization direction of this type of piezoelectric actuator 100 is a single direction.

[0090] In Figure 5 , since the polarization directions of both the first piezoelectric layer and the second piezoelectric layer are "the direction in which the signal layer 236 faces the ground layer", the polarization directions of the first piezoelectric layer and the second piezoelectric layer are regarded as the same, that is, the polarization direction of this type of piezoelectric actuator 100 is a single direction.

[0091] In Figure 6 , since the polarization direction of the first piezoelectric layer is "the direction in which the ground layer faces the signal layer 236" and the polarization direction of the second piezoelectric layer is "the direction in which the signal layer 236 faces the ground layer", the polarization directions of the first piezoelectric layer and the second piezoelectric layer are regarded as opposite, that is, the polarization direction of this type of piezoelectric actuator 100 is two directions.

[0092] In Figure 7 , since the polarization direction of the first piezoelectric layer is "the direction in which the signal layer 236 faces the ground layer" and the polarization direction of the second piezoelectric layer is "the direction in which the ground layer faces the signal layer 236", the polarization directions of the first piezoelectric layer and the second piezoelectric layer are regarded as opposite, that is, the polarization direction of this type of piezoelectric actuator 100 is two directions.

[0093] Compared with the piezoelectric actuator 100 having a single polarization direction, the piezoelectric actuator 100 having two polarization directions can excite a mode with a larger vibration quantity, that is, a larger vibration amplitude, and thus has a larger driving force and driving speed.

[0094] In the related art, the first grounding layer and the second grounding layer of the piezoelectric actuator 100 are connected to the same external electrode. Therefore, there is no difference between the first grounding layer and the second grounding layer. Thus, for the piezoelectric actuator 100, its polarization direction must be a single direction, that is, the polarization direction of the piezoelectric actuator 100 is "the direction from the signal layer towards the grounding layer", or the polarization direction is "the direction from the grounding layer towards the signal layer".

[0095] It can be seen that compared with the related art, the polarization direction of the piezoelectric actuator 100 provided in the present application can be not only a single direction but also two directions. When two polarization directions are adopted, the piezoelectric actuator 100 provided in the present application has a larger driving force and driving speed than the piezoelectric actuator 100 provided in the related art, that is, the energy density that can be output is larger. And in the case of the same output energy density, the volume of the piezoelectric actuator 100 provided in the present application can be made smaller.

[0096] In summary, in the piezoelectric actuator 100 provided in the present application, a suitable driving signal can be loaded onto the first ground layer 234, the second ground layer 235, and the signal layer 236 through the first outer electrode 231, the second outer electrode 232, and the third outer electrode 233, so as to excite each piezoelectric layer 237 to generate corresponding vibrations. Under the cooperative vibrations of multiple piezoelectric layers 237, the entire piezoelectric actuator 100 can present a corresponding motion form. Further, since the first ground layer 234 is connected to the first outer electrode 231 and the second ground layer 235 is connected to the second outer 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 formed by the first ground layer 234 and the signal layer 236 (abbreviated as the first electric field) and the direction of the electric field formed by the second ground layer 235 and the signal layer 236 (abbreviated as the first electric field) can be the same or different. Accordingly, the polarization direction of the piezoelectric layer 237 located between the first ground layer 234 and the signal layer 236 (abbreviated as the first polarization direction) and the polarization direction of the piezoelectric layer 237 located between the second ground layer 235 and the signal layer 236 (abbreviated as the second polarization direction) can be the same or different. Specifically, the piezoelectric actuator 100 needs to be polarized to have piezoelectric properties. When the directions of the first electric field and the second electric field used to polarize the piezoelectric layer 237 are the same, 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 towards the signal layer 236 and the second polarization direction is the direction from the second ground layer 235 towards the signal layer 236, or the first polarization direction is the direction from the signal layer 236 towards the first ground layer 234 and the second polarization direction is the direction from the signal layer 236 towards the second ground layer 235. For the piezoelectric actuator 100 with the same first and second polarization directions, its polarization direction is a single direction. When the directions of the first electric field and the second electric field used to polarize the piezoelectric layer 237 are different, 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 towards the signal layer 236 and the second polarization direction is the direction from the signal layer 236 towards the second ground layer 235, or the first polarization direction is the direction from the signal layer 236 towards the first ground layer 234 and the second polarization direction is the direction from the second ground layer 235 towards the signal layer 236. For the piezoelectric actuator 100 with different first and second polarization directions, its polarization direction is two directions. Compared with the related art, when the piezoelectric actuator 100 provided in the present application adopts the two-polarization-direction scheme, it has a greater driving force and driving speed, that is, the energy density that can be output is greater, and under the condition of the same output energy density, the volume of the piezoelectric actuator 100 provided in the present application can be made smaller.In addition, the polarization direction of the piezoelectric actuator 100 can be a single direction or two directions, indicating that the polarization method of the piezoelectric actuator 100 is diversified and the design flexibility is higher, so that it can be adapted to more driving scenarios.

[0097] Please refer to Figure 3 and Figure 4 , each signal layer 236 includes a plurality of signal electrodes X236, and the plurality of signal electrodes X236 are arranged at intervals from each other. That is to say, the signal electrodes X236 located on the same layer are not connected to each other. It should be noted that the "plurality of signal electrodes X236" corresponds to "one signal layer 236", rather than "the entire piezoelectric actuator 100". For example, if one signal layer 236 includes N signal electrodes X236 and a piezoelectric actuator 100 includes M signal layers 236, then a piezoelectric actuator 100 includes N*M signal electrodes X236.

[0098] Furthermore, the third outer electrode 233 includes a plurality of sub-electrodes X233, and the number of sub-electrodes X233 is the same as the number of signal electrodes X236 included in one signal layer 236, and can specifically be 2, 3, 4, 5, 6, etc. In this application, only 2 is taken as an example for illustration. Different sub-electrodes X233 are electrically connected to different signal electrodes X236, that is, the sub-electrodes X233 and the signal electrodes X236 are electrically connected in one-to-one correspondence.

[0099] In this embodiment, since different sub-electrodes X233 are electrically connected to different signal electrodes X236, different signal electrodes X236 are independent of each other, so that the polarization directions of the piezoelectric layer 237 portions corresponding to different signal electrodes X236 can be the same or different, thus making the polarization method of the piezoelectric actuator 100 diversified and the design flexibility higher, so that it can be adapted to more driving scenarios.

[0100] Please refer to Figure 8 and Figure 9 , the first grounding 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 split structure. Among them, the first body portion 2341 is disposed opposite to the signal layer 236, that is, the orthographic projection of the first body portion 2341 on the signal layer 236 at least partially falls within the range where the signal layer 236 is located. The first body portion 2341 is spaced from the periphery of the first surface 2371 of the piezoelectric layer 237 to prevent the first body portion 2341 from directly contacting the outer 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 outer electrode 231, so that the first body portion 2341 is electrically connected to the first outer electrode 231 through the first lead-out portion 2342.

[0101] Please refer to Figure 8 and Figure 10 , the second grounding layer 235 includes a second main body portion 2351 and a second lead portion 2352. The second lead portion 2352 and the second main body portion 2351 may be an integral structure or a split structure. Among them, the second main body portion 2351 is disposed opposite to the signal layer 236, that is, the orthographic projection of the second main body portion 2351 on the signal layer 236 at least partially falls within the range where the signal layer 236 is located. The second main body portion 2351 is spaced apart from the periphery of the first surface 2371 of the piezoelectric layer 237 to prevent the second main body portion 2351 from directly contacting the outer electrode. One end of the second lead portion 2352 is connected to the second main body portion 2351, and the other end of the second lead portion 2352 is connected to the second outer electrode 232, so that the second main body portion 2351 is electrically connected to the second outer electrode 232 through the second lead portion 2352.

[0102] Furthermore, the projections formed by the first lead portion 2342 and the second lead portion 2352 on the piezoelectric layer 237 do not overlap. With such an arrangement, it is convenient for the first outer electrode 231 to be connected to the first lead portion 2342, and it is convenient for the second outer electrode 232 to be connected to the second lead portion 2352, and it can ensure that the first outer electrode 231 and the second outer electrode 232 are spaced apart.

[0103] Please refer to Figure 8 and Figure 9 , the first main body portion 2341 has a first end D1 and a second end D2 that are far away from each other. The first end D1 is closer to the second lead portion 2352 than the second end D2. The first lead portion 2342 is connected to the second end D2. In short, the first lead portion 2342 is connected to one end of the first main body portion 2341 that is far away from the second lead portion 2352.

[0104] Please refer to Figure 8 and Figure 10 , the second main body portion 2351 has a third end D3 and a fourth end D4 that are far away from each other. The fourth end D4 is closer to the first lead portion 2342 than the third end D3. The second lead portion 2352 is connected to the third end D3. In short, the second lead portion 2352 is connected to one end of the second main body portion 2351 that is far away from the first lead portion 2342.

[0105] According to the above arrangement form, the first lead portion 2342 and the second lead portion 2352 can be farthest away from each other, which can preferably avoid the problem that the first outer electrode 231 and the second outer electrode 232 come into contact due to errors during the manufacturing process of the piezoelectric actuator 100.

[0106] The edges of at least one of the first grounding layer 234, the second grounding layer 235, and the signal layer 236 are flush with the second surface 2372.

[0107] Optionally, at least part of the edge of the signal layer 236 is flush with the second surface 2372, as Figure 3 shown. With such a setting, the third outer electrode 233 can be flatly connected to the signal layer 236 of each layer, so that all the signal layers 236 are connected in parallel through the third outer electrode 233.

[0108] Optionally, at least part of the edge of the first ground layer 234 is flush with the second surface 2372, as Figure 9 shown. With such a setting, the first outer electrode 231 can be flatly connected to the first ground layer 234 of each layer, so that all the first ground layers 234 are connected in parallel through the first outer electrode 231.

[0109] Optionally, at least part of the edge of the second ground layer 235 is flush with the second surface 2372, as Figure 10 shown. With such a setting, the second outer electrode 232 can be flatly connected to the second ground layer 235 of each layer, so that all the second ground layers 235 are connected in parallel through the second outer electrode 232.

[0110] Please refer to Figures 11 to 12 , further, 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 and the second side surface 2372b face away from each other, and the third side surface 2372c and the fourth side surface 2372d face away from each other.

[0111] In one embodiment, as Figure 11 shown, the third outer electrode 233 is disposed on the first side surface 2372a, and the first outer electrode 231 and the second outer electrode 232 are disposed on the second side surface 2372b.

[0112] In another embodiment, as Figure 12 shown, the third outer electrode 233 is disposed on the first side surface 2372a, the first outer electrode 231 is disposed on the fourth side surface 2372d, and the second outer electrode 232 is disposed on the third side surface 2372c.

[0113] Of course, in addition to the above two embodiments, the relative positional relationship of the first outer electrode 231, the second outer electrode 232, and the third outer electrode 233 can also be in other forms, which will not be elaborated one by one here.

[0114] Generally speaking, under the same voltage condition, the more the number of stacked piezoelectric layers 237, the greater the output power of the piezoelectric actuator 100. Therefore, by stacking multiple piezoelectric layers 237, the piezoelectric actuator 100 can have a relatively large output power. According to the driving requirements, the number of piezoelectric layers 237 can be, but is not limited to, 2, 3, 4, 5, 6, 7, 8, 9, etc. Here are several examples of different numbers of piezoelectric layers 237.

[0115] Please refer to Figure 13 , in one embodiment, the number of piezoelectric layers 237 in the Z-axis direction is 2. In the illustrated structure of the piezoelectric actuator 100, the number of signal layers 236, the first grounding layer 234, and the second grounding layer 235 is all 1, and the signal layer 236 is disposed between the first grounding layer 234 and the second grounding layer 235.

[0116] Please refer to Figures 4 to 7 , in another embodiment, the number of piezoelectric layers 237 in the Z-axis direction is 3. In the illustrated structure of the piezoelectric actuator 100, the number of signal layers 236 in the Z-axis direction is 2, and the number of the first grounding layer 234 and the second grounding layer 235 is both 1.

[0117] Please refer to Figure 14 , in yet another embodiment, the number of piezoelectric layers 237 in the Z-axis direction is 4. In the illustrated structure of the piezoelectric actuator 100, the number of signal layers 236 in the Z-axis direction is 2, the number of the first grounding layer 234 in the Z-axis direction is 2, and the number of the second grounding layer 235 is 1. It can be understood that in Figure 14 , after swapping the positions of any one of the first grounding layers 234 and the second grounding layer 235, a different arrangement structure can be formed.

[0118] It should be noted that in the structure of the piezoelectric actuator 100, the number of the first grounding layer 234 and the second grounding layer 235 can be the same or different, and the number of the first grounding layer 234 and the second grounding layer 235 can be multiple or one. Here, an exemplary description will be given for the case where both the first grounding layer 234 and the second grounding layer 235 are multiple.

[0119] Please refer to Figure 15 , the piezoelectric body 23 is divided into a first region A1 and a second region A2 along the Z-axis direction. The number of the first grounding layer 234, the second grounding layer 235, and the signal layer 236 is all multiple, and the specific number can be 2, 3, 4, 5, etc.

[0120] Multiple signal layers 236 are simultaneously disposed in the first region A1 and the second region A2, and all the signal layers 236 are connected in parallel through the third external electrode 233.

[0121] A plurality of first ground layers 234 are disposed in the first region A1, and the first ground layers 234 and the signal layers 236 are alternately arranged. That is to say, within 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. Moreover, all the first ground layers 234 are connected in parallel through the first external electrode 231.

[0122] A plurality of second ground layers 235 are disposed in the second region A2, and the second ground layers 235 and the signal layers 236 are alternately arranged. That is to say, within 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. Moreover, all the second ground layers 235 are connected in parallel through the second external electrode 232.

[0123] In the embodiment, each external electrode is electrically connected to each internal electrode, so that the internal electrodes of the same name in different layers form a parallel structure in the circuit. Assuming that the number of layers of the piezoelectric layer 237 is n, then when a voltage U is applied, the piezoelectric actuator 100 can obtain a driving effect of n*U voltage. In addition, the first ground layer 234 is disposed in the first region A1, and the second ground layer 235 is disposed in the second region A2. The polarization directions of the first region A1 and 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, and thus a larger driving force and driving speed can be obtained.

[0124] Next, based on the Figure 15 shown structure, the polarization scheme of the piezoelectric actuator 100 will be further described.

[0125] Please refer to Figure 15 , each signal layer 236 includes a first signal electrode 2361 and a second signal electrode 2362, and the first signal electrode 2361 and the second signal electrode 2362 are arranged at intervals. In Figure 15 , the first signal electrode 2361 and the second signal electrode 2362 are arranged along the X-axis. In other embodiments, they can also be arranged along the Y-axis, or arranged in other directions inclined to the X-axis and the Y-axis, which are not limited herein.

[0126] Taking 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 to say, after the regions are divided, the first signal electrode 2361 is located in the first sub-region A11 and the third sub-region A21, and the second signal electrode 2362 is located in the second sub-region A12 and the fourth sub-region A22.

[0127] The third outer 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.

[0128] 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 outer electrode 231, the polarization directions of all the piezoelectric layers 237 in the first sub-region A11 are the same.

[0129] 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 outer electrode 231, the polarization directions of all the piezoelectric layers 237 in the second sub-region A12 are the same.

[0130] 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 outer electrode 232, the polarization directions of all the piezoelectric layers 237 in the third sub-region A21 are the same.

[0131] 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 outer electrode 232, the polarization directions of all the piezoelectric layers 237 in the fourth sub-region A22 are the same.

[0132] It can be understood that through the above setting form, 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 of 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 a variety of polarization forms.

[0133] Next, Figure 15 several feasible polarization forms of the piezoelectric actuator 100 shown are illustrated.

[0134] Please refer to Figure 15 and Figure 16, the first polarization form of the piezoelectric actuator 100 is as follows: within the first sub-region A11, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 towards the first signal electrode 2361. Within the second sub-region A12, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 towards the second signal electrode 2362. Within the third sub-region A21, the polarization direction of the piezoelectric layer 237 is from the first signal electrode 2361 towards the second ground layer 235. Within the fourth sub-region A22, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 towards the second ground layer 235.

[0135] Please refer to Figure 17 and Figure 18 , the second polarization form of the piezoelectric actuator 100 is as follows: within the first sub-region A11, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 towards the first signal electrode 2361. Within the second sub-region A12, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 towards the first ground layer 234. Within the third sub-region A21, the polarization direction of the piezoelectric layer 237 is from the first signal electrode 2361 towards the second ground layer 235. Within the fourth sub-region A22, the polarization direction of the piezoelectric layer 237 is from the second ground layer 235 towards the second signal electrode 2362.

[0136] Please refer to Figure 19 and Figure 20 , the third polarization form of the piezoelectric actuator 100 is as follows: within the first sub-region A11, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 towards the first signal electrode 2361. Within the second sub-region A12, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 towards the first ground layer 234. Within the third sub-region A21, the polarization direction of the piezoelectric layer 237 is from the second ground layer 235 towards the first signal electrode 2361. Within the fourth sub-region A22, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 towards the second ground layer 235.

[0137] Please refer to Figure 21 and Figure 22 , the fourth polarization form of the piezoelectric actuator 100 is as follows: within the first sub-region A11, the polarization direction of the piezoelectric layer 237 is from the first signal electrode 2361 towards the first ground layer 234. Within the second sub-region A12, the polarization direction of the piezoelectric layer 237 is from the first ground layer 234 towards the second signal electrode 2362. Within the third sub-region A21, the polarization direction of the piezoelectric layer 237 is from the second ground layer 235 towards the first signal electrode 2361. Within the fourth sub-region A22, the polarization direction of the piezoelectric layer 237 is from the second signal electrode 2362 towards the second ground layer 235.

[0138] Please refer to Figure 23 and Figure 24 In addition, the present application also provides a piezoelectric drive module 200, which includes a carrier 201, a driven member 202, and a piezoelectric driver 100 as described in any of the above embodiments. The piezoelectric driver 100 is disposed on the carrier 201, and the side of the friction layer 24 of the piezoelectric driver 100 facing away from the piezoelectric body 23 is in contact with the driven member 202.

[0139] When the piezoelectric driver 100 is loaded with an appropriate alternating drive signal, the piezoelectric driver 100 can generate high-frequency micro-amplitude vibrations, and then convert its own microscopic motion into the macroscopic motion of the driven member 202 through the frictional action between the friction layer 24 and the driven member 202. The motion form of the driven member 202 can be linear motion or rotational motion. Here, only linear motion is shown for illustration.

[0140] Refer to Figure 23 and Figure 25 As shown, in some embodiments, the piezoelectric drive module 200 further includes a pre-tightening member 205. The pre-tightening member 205 is connected to the carrier 201 and is used to apply a pre-tightening force pointing to the driven member 202 to the piezoelectric driver 100 on the side of the piezoelectric driver 100 facing away from the driven member 202, so as to press the friction layer 24 of the piezoelectric driver 100 against the driven member 202, so that the frictional force between the friction layer 24 and the driven member 202 can convert the microscopic motion of the piezoelectric driver 100 itself into the macroscopic motion of the driven member 202.

[0141] The pre-tightening member 205 includes but is not limited to elastic structures such as elastic sheets, and can elastically press the piezoelectric driver 100 against the driven member 202. Both ends of the pre-tightening member 205 can be connected to the carrier 201, and the middle part of the pre-tightening member 205 presses against the side of the piezoelectric driver 100 facing away from the driven member 202.

[0142] In some embodiments, the piezoelectric drive module 200 further includes a buffer member 206. The buffer member 206 is disposed between the piezoelectric driver 100 and the pre-tightening member 205 and is pressed against the piezoelectric driver 100 by the pre-tightening member 205. The buffer member 206 can provide a buffering effect on the piezoelectric driver 100, which is beneficial to reducing wear and noise during the operation of the piezoelectric driver 100. The material of the buffer member 206 includes but is not limited to any suitable buffer materials such as rubber, foam, silica gel, polymers, etc.

[0143] In some embodiments, the opposite sides of the buffer member 206 are adhesive to adhere the piezoelectric actuator 100 and the pre-tightening member 205. Thus, the buffer member 206 adheres the piezoelectric actuator 100 and the pre-tightening member 205 to form an integral structure, which can further reduce the wear and noise during the operation of the piezoelectric actuator 100 and improve the structural reliability of the piezoelectric drive module 200. The opposite sides of the buffer member 206 can be provided with tapes to have adhesiveness, and the buffer member 206 can also adopt structures such as buffer tapes with buffering and adhesive functions.

[0144] Reference Figure 24 、 Figure 26 and Figure 27 As shown in, in some embodiments, the piezoelectric drive module 200 further includes a first magnetic mating member 207 and a second magnetic mating member 208. The first magnetic mating member 207 is disposed on the carrier 201, and the second magnetic mating member 208 is disposed on the driven member 202. The first magnetic mating member 207 and the second magnetic mating member 208 are configured to be able to attract each other through magnetic attraction. Thus, the piezoelectric drive module 200 can make the carrier 201 and the driven member 202 tend to approach each other by means of the magnetic attraction between the first magnetic mating member 207 and the second magnetic mating member 208, so as to be able to apply a pre-tightening force pointing to the driven member 202 to the piezoelectric actuator 100, and can also press the friction layer 24 against the driven member 202, so as to facilitate the movement of the driven member 202 by the frictional force between the friction layer 24 and the driven member 202. At the same time, the first magnetic mating member 207 and the second magnetic mating member 208 are respectively disposed on the carrier 201 and the driven member 202. For example, they can be at least partially embedded or accommodated on the carrier 201 and the driven member 202, and the pre-tightening member 205 is omitted, which is beneficial to reducing the volume of the piezoelectric drive module 200. And, by setting the pre-tightening force on the piezoelectric actuator 100 through magnetic attraction, the first magnetic mating member 207 and the second magnetic mating member 208 do not need to contact the piezoelectric actuator 100, which is beneficial to reducing the noise and wear during the operation of the piezoelectric actuator 100.

[0145] The specific settings of the first magnetic mating member 207 and the second magnetic mating member 208 are not limited, as long as the magnetic attraction generated by the first magnetic mating member 207 and the second magnetic mating member 208 can press the friction layer 24 against the driven member 202 to meet the requirements of the frictional force. In the drawings of the present application, taking the first magnetic mating member 207 as a magnet and the second magnetic mating member 208 as a steel sheet as an example, the materials of the first magnetic mating member 207 and the second magnetic mating member 208 can also be swapped, or both the first magnetic mating member 207 and the second magnetic mating member 208 are magnets.

[0146] In some embodiments, one of the first magnetic fitting 207 and the second magnetic fitting 208 is an electromagnetic structure, such as an electromagnet composed of a coil and an iron core. Thus, by adjusting the magnitude of the current applied to the electromagnetic structure, the magnitude of the pre-tightening force between the piezoelectric actuator 100 and the driven member 202 can also be adjusted to meet different driving requirements.

[0147] In some embodiments, when the piezoelectric drive module 200 is provided with the first magnetic fitting 207 and the second magnetic fitting 208, the piezoelectric drive module 200 further includes a rolling member 209. The rolling member 209 is disposed between the carrier 201 and the driven member 202 and is in rolling engagement with the carrier 201 and the driven member 202. The provision of the rolling member 209 can provide a structural basis for the relative movement between the carrier 201 and the driven member 202, making the sliding of the driven member 202 relative to the carrier 201 smoother under the drive of the piezoelectric actuator 100.

[0148] In some embodiments, at least one of the two opposite surfaces of the carrier 201 and the driven member 202 is provided with a rolling groove 204. The extending direction of the rolling groove 204 is parallel to the relative sliding direction of the carrier 201 and the driven member 202. The rolling member 209 is rollably disposed in the rolling groove 204. The provision of the rolling groove 204 can provide a limiting effect on the rolling member 209, thereby restricting the sliding direction of the driven member 202 relative to the carrier 201. At the same time, it can also prevent the rolling member 209 from coming out, which is beneficial to improving the structural reliability of the piezoelectric drive module 200.

[0149] The number of the rolling grooves 204 and the number of the rolling members 209 are not limited, and can be specifically set according to the relative sliding requirements of the driven member 202 and the carrier 201. In the drawings of the present application, two rolling grooves 204 are provided on the side of the carrier 201 facing the driven member 202, and three rolling members 209 are sequentially provided in each rolling groove 204 as an example. The rolling member 209 includes, but is not limited to, any applicable structure such as a ball.

[0150] Reference Figure 27 As shown, in some embodiments, the piezoelectric drive module 200 further includes a friction member 210. The friction member 210 is disposed on the driven member 202 and contacts the friction layer 24. The provision of the friction member 210 can increase the frictional force between the driven member 202 and the piezoelectric actuator 100, so that the driven member 202 can be more easily driven to move through the frictional action between the friction layer 24 and the friction member 210. The friction member 210 can be a sheet-like structure disposed on the driven member 202, and the material of the friction member 210 includes, but is not limited to, any applicable material such as polytetrafluoroethylene, nylon, polyester, metal, ceramic, etc.

[0151] In some embodiments, the surface of the friction member 210 facing the friction layer 24 is provided with periodically arranged textures or aperiodically arranged patterns 241. For the specific types of the textures or patterns 241 provided on the friction member 210, reference may be made to the above-mentioned friction layer 24. Providing the textures or patterns 241 on the friction member 210 is beneficial to increasing the contact area between the friction member 210 and the friction layer 24, further enhancing the friction effect between the friction member 210 and the friction layer 24, so as to improve the driving effect of the piezoelectric actuator 100 on the driven member 202. At the same time, when a lubricating medium such as a lubricant is provided between the friction member 210 and the friction layer 24, the textures or patterns 241 on the friction member 210 and the friction layer 24 can also capture and retain the medium, which is beneficial to enhancing the friction performance.

[0152] Please refer to Figure 28 , in some embodiments, the piezoelectric drive module 200 is a piezoelectric motor, then the driven member 202 serves as the mover of the piezoelectric drive module 200, and the piezoelectric actuator 100 serves as the stator of the piezoelectric drive module 200. Among them, the carrier 201 can be a protective shell, which is used for storage and protection. The piezoelectric actuator 100 is connected to (such as bonded or welded to) the carrier 201. The specific connection method is related to the structural design and modal design and is not limited herein. The driven member 202 is movably connected to the carrier 201. The friction head 10 of the piezoelectric actuator 100 abuts against the driven member 202 to drive the driven member 202 to move along the second preset direction F2.

[0153] The piezoelectric drive module 200 may further include a rolling element 203. The rolling element 203 can be a spherical ball or a cylindrical roller. The rolling element 203 is disposed between the driven member 202 and the carrier 201 so that the driven member 202 can move relative to the carrier 201. When the driven member 202 moves relative to the carrier 201 under the action of the piezoelectric actuator 100, the piezoelectric drive module 200 can output a driving force through the driven member 202 to drive an element outside the piezoelectric drive module 200 to move.

[0154] Please refer to Figure 29 and Figure 30 , in some other embodiments, the piezoelectric drive module 200 may also be a camera module. Then, the piezoelectric drive module 200 may include a lens and an image sensor 211. The driven member 202 can be either the lens or the image sensor 211. The driven member 202 is movably disposed on the carrier 201, and the piezoelectric actuator 100 is fixed on the carrier 201 and the friction layer 24 faces the driven member 202 and contacts the driven member 202.

[0155] Among them, the lens is used to collect the light of the photographed scene and focus the light on the image sensor 211. The image sensor 211 is also called a photosensitive chip or photosensitive element or Sensor, which is used to receive the light passing through the lens and convert the optical signal into an electrical signal. The image sensor 211 can be a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS).

[0156] When the lens is the driven member 202, the piezoelectric driver 100 can be directly or indirectly connected to the lens. Then the lens serves as the driven member 202 to drive the lens to move during the operation of the camera module, so as to realize the AF (autofocus) function and / or OIS (optical image stabilization) function of the camera module.

[0157] In one embodiment, the piezoelectric driver 100 can drive the lens to move relative to the image sensor 211 along the extension direction of the optical axis G to realize the AF (autofocus) function of the camera module, such as Figure 29 shown.

[0158] In another embodiment, the piezoelectric driver 100 can drive the lens to move relative to the image sensor 211 in a direction perpendicular to the optical axis G to realize the OIS (optical image stabilization) function of the camera module, such as Figure 30 shown.

[0159] In yet another embodiment, a plurality of piezoelectric drivers 100 are provided in the camera module. Among them, at least one piezoelectric driver 100 is used to realize the AF (autofocus) function of the camera module, and at least one piezoelectric driver 100 is used to realize the OIS (optical image stabilization) function of the camera module.

[0160] Of course, in other embodiments, the piezoelectric driver 100 can also be used to drive the image sensor 211 to move relative to the lens to realize the AF (autofocus) function and / or OIS (optical image stabilization) function of the camera module.

[0161] Please refer to Figure 31 , this application also provides an electronic device 300. The electronic device 300 includes a device body 302 and the piezoelectric drive module 200 described in any of the above embodiments. The piezoelectric drive module 200 is installed on the device body 302.

[0162] Among them, the electronic device 300 can be a mobile phone, a tablet computer, a laptop computer, a wearable device (such as a smart watch, a bracelet, a VR device, etc.), a television, a vehicle-mounted device, an e-reader, etc. It should be noted that the embodiments of this application only take the electronic device 300 as a mobile phone for exemplary illustration.

[0163] The device body 302 refers to the main part of the electronic device 300, which includes functional components that implement the main functions of the electronic device 300 and a mechanical structure that protects and carries these functional components. Taking a mobile phone as an example, the device body 302 may include a display screen, a middle frame, and a battery cover. The display screen and the battery cover are both connected to the middle frame and are respectively arranged on opposite sides of the middle frame.

[0164] When the piezoelectric drive module 200 is a camera module, the piezoelectric drive module 200 can be a direct-drive camera or a periscope camera. Among them, a periscope camera refers to a camera in which the optical axis G is bent (such as a 90° bend), and a direct-drive camera refers to a camera in which the optical axis G is a non-bent straight line. According to actual needs, the light-transmitting window of the piezoelectric drive module 200 can be arranged at any position of the electronic device 300. Taking a mobile phone as an example, the light-transmitting window of the piezoelectric drive module 200 can be arranged on the front, back, or side of the mobile phone. Among them, the so-called front side refers to the side of the mobile phone with the display screen; the so-called back side refers to the side of the mobile phone with the battery cover; the so-called side refers to the circumferential side of the middle frame of the mobile phone. It can be understood that for different types of electronic devices 300, the definitions of the front side, back side, side, etc. may be different, and other types of electronic devices 300 are not listed and explained one by one here.

[0165] In the related art, an electromagnetic motor is used in the camera module to drive the lens movement to achieve AF (autofocus) function and OIS (optical image stabilization) function. However, the magnetic field generated by the electromagnetic motor will interfere with other electronic components in the electronic device 300. In this application, the piezoelectric drive module 200 uses the piezoelectric actuator 100, and the piezoelectric actuator 100 does not generate a magnetic field during operation, thereby avoiding the problem of magnetic field interference.

[0166] When the piezoelectric actuator 100 described in any of the above embodiments is used in the piezoelectric drive module 200 and the electronic device, the piezoelectric actuator 100 is in direct or indirect contact with the driven member 202 through the friction layer 24 of the layer structure, and drives the driven member 202 to move by means of the friction between the friction layer 24 and the driven member 202. Compared with traditional structures such as friction heads, the setting of the friction layer 24 is beneficial to reducing the thickness dimension of the piezoelectric actuator 100, thereby being beneficial to reducing the occupied space of the piezoelectric actuator 100 in the piezoelectric drive module 200 and the electronic device, and being beneficial to the miniaturization design of the piezoelectric drive module 200 and the electronic device.

[0167] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0168] The embodiments described above merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A piezoelectric actuator, characterized in that, Comprising: A piezoelectric body, at least a part of which can be applied with a voltage to generate a deformation movement; And, A friction layer, provided on the piezoelectric body and used to contact a driven member, the surface friction coefficient of the friction layer being greater than that of the piezoelectric body, and the hardness of the friction layer being greater than that of the piezoelectric body.

2. The piezoelectric actuator according to claim 1, characterized in that, The piezoelectric body has two surfaces arranged opposite to each other, and the friction layer is laid flat on one of the surfaces of the piezoelectric body.

3. The piezoelectric actuator according to claim 1, wherein The piezoelectric actuator further includes a first protective layer and a second protective layer, the first protective layer and the second protective layer being respectively provided on two opposite sides of the piezoelectric body in a one-to-one correspondence, wherein: The friction layer is formed on the side of the first protective layer facing away from the piezoelectric body, or the friction layer is provided on the side of the first protective layer facing away from the piezoelectric body.

4. The piezoelectric actuator according to claim 1, characterized in that The friction layer is formed by a hardening treatment, or the friction layer is a surface coating provided on the piezoelectric body.

5. The piezoelectric actuator according to claim 4, characterized in that, The hardening treatment includes carburizing treatment, nitriding treatment or metal infiltration treatment; the surface coating includes a metal film layer, a ceramic film layer or a polymer material film layer.

6. The piezoelectric actuator according to claim 1, wherein The side of the friction layer facing away from the piezoelectric body is provided with periodically arranged textures or non-periodically arranged patterns.

7. The piezoelectric actuator according to claim 1, characterized in that, The piezoelectric body includes a first outer electrode, a second outer electrode, a third outer electrode, a first ground layer, a second ground layer, a signal layer and a plurality of piezoelectric layers; the plurality of piezoelectric layers are sequentially arranged at intervals along a first preset direction, and each piezoelectric layer has two first surfaces facing away from each other in the first preset direction and a second surface connected to the first surfaces; The first ground layer, the second ground layer and the signal layer are respectively connected to different first surfaces, so that the electrodes on two opposite sides of the same piezoelectric layer are respectively the signal layer and the first ground layer, or the electrodes on two opposite sides of the same piezoelectric layer are respectively the signal layer and the second ground layer; The first outer electrode, the second outer electrode and the third outer electrode are all connected to the second surface, and the first outer electrode is electrically connected to the first ground layer, the second outer electrode is electrically connected to the second ground layer, and the third outer electrode is electrically connected to the signal layer.

8. A piezoelectric drive module, characterized in that, Comprising a carrier, a driven member and a piezoelectric actuator according to any one of claims 1-7, the piezoelectric actuator being provided on the carrier, and the side of the friction layer of the piezoelectric actuator facing away from the piezoelectric body contacting the driven member.

9. The piezoelectric driving module according to claim 8, wherein The piezoelectric drive module further includes a pre-tightening member and a buffer member, the pre-tightening member being connected to the carrier and used to apply a pre-tightening force pointing to the driven member to the piezoelectric actuator on the side of the piezoelectric actuator facing away from the driven member, and the buffer member being provided between the piezoelectric actuator and the pre-tightening member.

10. The piezoelectric drive module according to claim 9, characterized in that, Both sides of the buffer member have adhesiveness to adhere the piezoelectric actuator and the pre-tightening member.

11. The piezoelectric drive module according to claim 8, characterized in that, The piezoelectric drive module further includes a first magnetic mating member and a second magnetic mating member. The first magnetic mating member is disposed on the carrier, and the second magnetic mating member is disposed on the driven member. The first magnetic mating member and the second magnetic mating member are configured to be attracted to each other by magnetic attraction.

12. The piezoelectric drive module according to claim 11, wherein At least one of the first magnetic mating member and the second magnetic mating member is an electromagnet.

13. The piezoelectric drive module according to claim 11, wherein The piezoelectric drive module further includes a rolling member. The rolling member is disposed between the carrier and the driven member and is in rolling cooperation with the carrier and the driven member.

14. The piezoelectric drive module according to claim 8, wherein, The piezoelectric drive module further includes a friction member. The friction member is disposed on the driven member and contacts the friction layer. The surface of the friction member facing the friction layer is provided with periodically arranged textures or non-periodically arranged patterns.

15. The piezoelectric drive module according to claim 8, wherein, The piezoelectric drive module is a piezoelectric motor, the driven member is a mover, and the driven member is movably connected to the carrier.

16. The piezoelectric drive module according to claim 8, wherein, The piezoelectric drive module is a camera module, the driven member is a lens or an image sensor, and the driven member is disposed on the carrier.

17. An electronic device, characterized in that, Including the piezoelectric drive module according to any one of claims 8-16.

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