Driving unit, piezoelectric motor, camera module, and electronic device

Abstract

The present application provides a driving unit, a piezoelectric motor, a camera module, and an electronic device. The driving unit comprises a driving body, an elastic cantilever, and a fixing part; the driving body comprises an elastic carrier plate, and a driving protrusion and a piezoelectric ceramic provided on the carrier plate; the elastic cantilever is provided with a bent part; the fixing part is used for mounting the driving unit; and the fixing part and the driving body are connected by means of the elastic cantilever. In the present application, the provision of the bent part on the elastic cantilever can weaken the rigidity of the elastic cantilever, so as to increase the flexibility of the elastic cantilever, so that the elastic cantilever is more prone to deformation under the action of external force; and the elastic cantilever having the bent part is used to connect the fixing part to the driving body, so that when preload is applied to the driving unit, the elastic cantilever can deform to reduce the degree of deformation of the driving body, thereby reducing the impact of preload on the appearance of the driving body, i.e., reducing the impact of the magnitude of preload on the degree of deformation of the driving body and reducing the sensitivity of the driving body to preload.

Description

Drive unit, piezoelectric motor, camera module and electronic equipment

[0001] This application claims priority to Chinese patent application filed on July 30, 2024, with application number 202411038845.X and entitled "Drive Unit, Piezoelectric Motor, Camera Module and Electronic Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of motor technology, and in particular to a drive unit, a piezoelectric motor, a camera module, and an electronic device. Background Technology

[0003] Electronic devices typically require a drive mechanism to move the movable lens barrel of a lens assembly to achieve focusing. Currently, this can be achieved using voice coil motors, piezoelectric motors, and other similar devices. Compared to voice coil motors, piezoelectric motors are increasingly being used due to their advantages such as high power density, small size, absence of magnetic interference, and self-locking capability in the event of power failure.

[0004] Piezoelectric motors typically consist of a friction plate and a drive unit, with the friction plate and drive unit maintaining an initial preload state. Due to insufficient assembly process precision or other issues, the preload on the drive unit may be excessive, causing significant deformation of the drive unit, deteriorating drive precision, and affecting the focusing effect of the camera module. Summary of the Invention

[0005] This application provides a drive unit, a piezoelectric motor, a camera module, and an electronic device, which have high drive accuracy and can improve the focusing effect of the camera module.

[0006] Firstly, a driving unit is provided, comprising:

[0007] A driving body, the driving body including an elastic carrier plate and driving protrusions and piezoelectric ceramics disposed on the elastic carrier plate;

[0008] An elastic cantilever, wherein the elastic cantilever has a bending portion;

[0009] A fixing part is provided, which is connected to the drive body via the elastic cantilever. The fixing part is used to support the elastic cantilever and the drive body.

[0010] By incorporating a bend in the elastic cantilever, its rigidity can be reduced, thereby increasing its flexibility. This makes the elastic cantilever more prone to deformation under external forces. Connecting the fixed part to the drive unit using an elastic cantilever with a bend allows the cantilever to deform when preload is applied to the drive unit, thus reducing the degree of deformation of the drive unit and minimizing the impact of preload on its shape. This reduces the sensitivity of the drive unit to preload, allowing the drive unit to deform according to a preset pattern under alternating current. Consequently, the piezoelectric motor achieves higher driving precision, improving the focusing effect of the camera module and enabling electronic devices to capture higher-quality images or videos.

[0011] In one possible implementation, the elastic carrier plate includes a first excitation plate and a second excitation plate spaced apart, and a connecting plate connecting the first excitation plate and the second excitation plate. The driving protrusion is disposed on the connecting plate, and both the first excitation plate and the second excitation plate are provided with the piezoelectric ceramic.

[0012] By providing piezoelectric ceramics in both the first and second excitation plates, the first and second excitation plates can generate deformations respectively, and the bending deformations of the first and second excitation plates can be transmitted to the connecting plate, thereby causing the driving protrusion to generate a circular or elliptical trajectory perpendicular to the surface of the elastic carrier plate.

[0013] In some examples, the first excitation plate and the second excitation plate are parallel, and the connecting plate is perpendicular to the first excitation plate and the second excitation plate; in some embodiments, the connecting plate may not be perpendicular to the first excitation plate and the second excitation plate, that is, the angle between the connecting plate and the first excitation plate and the second excitation plate is an acute angle or an obtuse angle.

[0014] In some examples, each excitation plate has piezoelectric ceramics on only one side, that is, the first excitation plate has piezoelectric ceramics on only one side, and the second excitation plate has piezoelectric ceramics on only one side. The piezoelectric ceramics and the driving bumps can be located on the same side of the elastic carrier plate, or they can be located on opposite sides of the elastic carrier plate. In other examples, piezoelectric ceramics can be set on both sides of each excitation plate, that is, piezoelectric ceramics are set on both sides of the first excitation plate, and piezoelectric ceramics are also set on both sides of the second excitation plate.

[0015] In this example, the piezoelectric ceramic and the excitation plate have the same shape and size, meaning that the piezoelectric ceramic completely covers the sides of the first excitation plate / second excitation plate.

[0016] In one possible implementation, the first excitation plate, the second excitation plate, and the connecting plate are connected to form a U-shaped first edge surface, and at least one of the elastic cantilever arms is connected to the first edge surface.

[0017] There is a void area around the periphery of the first edge surface. Connecting the elastic cantilever to the first edge surface will result in a portion of the elastic cantilever being located within this void area. This reduces the size of the elastic cantilever protruding from the drive body, thereby reducing the size of the drive unit and the space occupied by the drive unit. This allows for a suitable reduction in the size of the piezoelectric motor, which in turn reduces the space occupied by the camera module on the electronic device, thus helping to shrink the size of the electronic device.

[0018] The side of the first excitation plate closest to the second excitation plate is called the first side, the side of the second excitation plate closest to the second excitation plate is called the second side, and the side of the connecting plate connected to the first and second sides is called the third side. In this example, the first side, the second side, and the third side are connected to form a U-shaped first edge surface.

[0019] The drive unit has multiple elastic cantilever arms. Some of the elastic cantilever arms can be connected to the side of the first excitation plate facing the second excitation plate, i.e., the elastic cantilever arms are connected to the first side. Other elastic cantilever arms can be connected to the side of the second excitation plate facing the first excitation plate, i.e., the elastic cantilever arms are connected to the second side. The elastic cantilever arms can also be connected to the side of the connecting plate, i.e., the elastic cantilever arms are connected to the third side.

[0020] In one possible implementation, the connecting plate includes a plate body connecting the first excitation plate and the second excitation plate, with both sides of the plate body extending in a direction away from the center of the plate body to form extension portions, the extension portions being located between the first excitation plate and the second excitation plate, and the driving protrusion being disposed on the plate body.

[0021] By exciting the two piezoelectric ceramics of the driving unit with two AC signals of zero phase difference, the first-order bending vibration mode of the driving unit under symmetrical constraint can be obtained; by exciting the two piezoelectric ceramics of the driving unit with two AC signals of 180° phase difference, the first-order bending vibration mode of the driving unit under antisymmetric constraint can be obtained. In fact, the natural frequency (first order) of the driving unit is affected by the excitation method. The first-order frequency of the driving unit under symmetrical constraint and antisymmetric constraint is different. In some embodiments, the first-order frequency of the driving unit under symmetrical constraint is f1, and the first-order frequency under antisymmetric constraint is f2, where f1≠f2.

[0022] By using two AC signals with a 90° phase difference to excite the two piezoelectric ceramics of the drive unit, a harmonic response mode can be obtained. In actual operation, using two AC signals with a 90° phase difference to excite the two piezoelectric ceramics of the drive unit can cause the drive bump to perform trajectory motion.

[0023] In one example, the extensions on both sides of the main body of the plate are arranged symmetrically.

[0024] The extensions alter the shape of the drive unit, thus affecting its natural frequencies (first order). Specifically, the extensions influence the first-order modal frequencies f1 and f2 under symmetric and antisymmetric constraints. In one example, the distance between the ends of the two extensions is W1. A larger W1 results in higher modal frequencies f1 under symmetric constraints and f2 under antisymmetric constraints; conversely, a smaller W1 results in lower frequencies f1 and f2. The dimensions of the main plate also affect f1 and f2. In one example, the width of the main plate is W2. A larger W2 results in lower f1, and vice versa. F2 is almost unaffected by W2. In another example, the width of the extensions is L1, and the length of the main plate is L2. L1 and L2 have a coupled effect on f1 and f2. Therefore, the extensions can adjust the first-order frequencies of the drive unit under symmetric and antisymmetric constraints to a certain extent, making the first-order frequencies f1 and f2 as close as possible under these constraints.

[0025] Therefore, the extension can adjust the values ​​of f1 and f2 by adjusting its own shape, thus reducing the range between f1 and f2. In actual operation, the frequency within the range of f1 to f2 can be selected to actually excite the two piezoelectric ceramics. This makes the movement trajectory of the driving bump approach a circle or ellipse, so that the driving bump has a more balanced thrust to push the friction plate to move. That is, the setting of the extension can optimize the movement trajectory of the driving bump, so that the driving bump can push the friction plate to move more stably, thereby making the piezoelectric motor have a stable driving force. The movable lens barrel in the camera module moves smoothly under the stable drive of the piezoelectric motor, which is beneficial to improving the focusing effect of the camera module.

[0026] In one example, the two ends of the plate body are connected to the middle area of ​​the side of the first excitation plate and the second excitation plate, respectively, and the extension is connected to the middle area of ​​the side of the plate body. In this way, the elastic carrier plate is symmetrical along its own axis, and the driving protrusion is set in the middle of the plate body, so that the driving protrusion is located at the center of the elastic carrier plate. The driving body is symmetrical along its own axis, which makes the trajectory of the driving protrusion closer to a circle or ellipse, thereby making the driving protrusion have a more balanced thrust to push the friction plate to move.

[0027] In one example, piezoelectric ceramics can also be provided on the extension.

[0028] In one possible implementation, the first excitation plate, the extension, and the plate body are connected to form a U-shaped second edge surface, and at least one of the elastic cantilever arms is connected to the second edge surface; and / or,

[0029] The second excitation plate, the extension, and the plate body are connected to form a U-shaped third edge surface, and at least one of the elastic cantilever arms is connected to the third edge surface.

[0030] There is a void area around the second and third edge surfaces. Connecting the elastic cantilever to the second or third edge surface will cause a part of the elastic cantilever to be located in the void area, which can reduce the size of the elastic cantilever protruding from the drive body. This can reduce the size of the drive unit, that is, the size of the piezoelectric motor can be appropriately reduced, thereby reducing the space occupied by the camera module on the electronic device and helping to reduce the size of the electronic device.

[0031] The side of the first excitation plate closest to the second excitation plate is called the first side, the side of the second excitation plate closest to the first excitation plate is called the second side, the third side of the connecting plate is located on the main body of the plate, the side of the main body of the plate connected to the first side is called the third side, the side of the extension connected to the third side is called the fourth side, the first side, the third side and the fourth side are connected to form a U-shaped second edge surface, the second side, the third side and the fourth side are connected to form a U-shaped third edge surface.

[0032] In one example, the driving body has multiple elastic cantilever arms. Some of the elastic cantilever arms can be connected to the side of the first excitation plate facing the second excitation plate, i.e., the elastic cantilever arm is connected to the first side. Other elastic cantilever arms can be connected to the side of the second excitation plate facing the first excitation plate, i.e., the elastic cantilever arm is connected to the second side. The elastic cantilever arms can also be connected to the side of the extension, i.e., the elastic cantilever arm is connected to the fourth side. The elastic cantilever arms can also be connected to the side of the connecting plate, i.e., the elastic cantilever arm is connected to the third side.

[0033] In one possible implementation, the piezoelectric ceramic is capable of exciting the elastic carrier plate into first-order bending vibration modes under symmetric and antisymmetric constraints, and the elastic cantilever is connected to a common node of the two first-order bending vibration modes.

[0034] The elastic plate is connected to the fixed part via an elastic cantilever, which is equivalent to the elastic cantilever providing support and constraint for the elastic plate. The node is the position where the modal vibration value is zero. In this embodiment, both the first and second excitation plates have nodal lines in their first-order bending vibration modes under symmetrical and anti-symmetrical constraints, and these nodal lines are essentially coincident, forming a common node. Therefore, at this common node, the amplitudes of the first and second excitation plates under both symmetrical and anti-symmetrical constraints are zero. Connecting the elastic cantilever to this common node can, on the one hand, reduce the impact of the elastic cantilever on the elastic plate. The amplitude of the plate vibration is reduced, thus reducing the impact on the deformation of the elastic carrier plate. On the other hand, it can also reduce the tension on the elastic cantilever during the deformation of the elastic carrier plate under the inverse piezoelectric effect, thereby reducing the impact of the deformation of the elastic carrier plate on the elastic cantilever, and further reducing the impact of the deformation of the elastic carrier plate on the fixed part. This ensures that the drive unit can be stably fixed in the piezoelectric motor during the operation of the drive unit, ensuring the reliability of the drive unit. As a result, the piezoelectric motor has a stable driving force, and the movable lens barrel in the camera module moves smoothly under the stable drive of the piezoelectric motor. This is beneficial to improving the focusing effect of the camera module.

[0035] In the first-order bending vibration mode, the excitation frequency of the external force used is equal to the natural frequency (first order) of the object. The closer the excitation frequency of the external force is to the natural frequency (first order) of the object, the easier it is for the elastic plate to resonate. As a result, the amplitude generated by the elastic plate will be larger, and the range of motion trajectory of the driving protrusion will be larger. Thus, the energy loss of the excitation will be smaller. Therefore, by selecting the first-order bending vibration mode under symmetric and antisymmetric constraints, the actual external force excitation frequency of the driving unit can be set to be close to the natural frequency (first order) of the piezoelectric ceramic. This can both reduce the energy loss of the excitation and improve the thrust-to-weight ratio of the driving unit.

[0036] Under symmetric and antisymmetric constraints, the fixed part always has a node. Thus, the amplitude generated by the excitation of the piezoelectric ceramic has little impact on the fixed part. When the driving unit is excited, the fixed part has almost no amplitude, that is, the fixed part basically does not produce displacement. This can reduce the tension between the fixed part and the components installed with it in the excited state, which is conducive to the stable connection of the fixed part and thus improves the reliability of the driving unit.

[0037] The common node for the formation of the first-order bending vibration mode under symmetric and antisymmetric constraints is located on the side of the first excitation plate near the second excitation plate (i.e., on the first side) and on the side of the second excitation plate near the first excitation plate (i.e., on the second side). The elastic cantilever can be connected to the side of the first excitation plate near the second excitation plate (i.e., connected to the first side) and the elastic cantilever can also be connected to the side of the second excitation plate near the first excitation plate (i.e., connected to the second side).

[0038] In one example, a fixed part can connect two elastic cantilever arms. The number of fixed parts and elastic cantilever arms are not equal. The fixed part can be provided with one fixing hole, or it can be provided with two, three or even more fixing holes.

[0039] In one example, the number of fixed parts and elastic cantilever arms are equal, with each fixed part connected to one elastic cantilever arm.

[0040] In one possible implementation, at least one of the elastic cantilever arms is connected to the side of the first excitation plate opposite to the second excitation plate; and / or,

[0041] At least one of the elastic cantilever arms is connected to the side of the second excitation plate opposite to the first excitation plate.

[0042] The connection point between the elastic cantilever and the drive body does not have to be located in the aforementioned empty area. Thus, the shape of the elastic cantilever is not limited by the size and shape of the aforementioned empty area, and the shape of the elastic cantilever can be designed according to actual needs.

[0043] In one possible implementation, the drive unit further includes a connecting arm, through which the two elastic cantilever arms are connected to the fixing part. That is, the fixing part can be connected to the two elastic cantilever arms through the connecting arm. In this way, the reserved connection area on the fixing part can be reduced, and the size of the fixing part can be appropriately reduced, thereby reducing the space occupied by the fixing part in the installation space. This can reduce the size of the piezoelectric motor, thereby reducing the space occupied by the piezoelectric motor in the camera module, and further reducing the space occupied by the camera module in the electronic device. This is beneficial to reducing the size and volume of the electronic device.

[0044] In one possible implementation, the piezoelectric ceramic includes a piezoelectric material layer and a first electrode layer electrically connected to the piezoelectric material layer. The first electrode layer is disposed between the piezoelectric material layer and the elastic carrier plate. The piezoelectric material layer also has a first flange portion electrically connected to the first electrode layer on its side away from the elastic carrier plate.

[0045] The first electrode layer is used to connect with the control circuit inside the piezoelectric motor, thereby transmitting electrical signals to the piezoelectric material layer, causing the piezoelectric material layer to deform due to the inverse piezoelectric effect. The first electrode layer is located between the piezoelectric material layer and the elastic carrier plate, making it difficult to connect with the control circuit. A first flange portion is provided on the side of the piezoelectric material layer away from the elastic carrier plate, which is electrically connected to the first electrode layer. The first flange portion is equivalent to an extension of the first electrode layer, reducing the difficulty of connecting the first electrode layer with the control circuit and also helping to improve the connection stability between the first electrode layer and the control circuit. This allows the piezoelectric ceramic to deform in a preset manner under the excitation of the AC signal from the control circuit, and the drive unit to generate a stable thrust, thereby giving the piezoelectric motor a stable driving force. The movable lens barrel in the camera module moves smoothly under the stable drive of the piezoelectric motor, which helps to improve the focusing effect of the camera module and enables the electronic device to capture images or videos of better quality.

[0046] The piezoelectric ceramic has two electrodes in its piezoelectric material layer. A fourth electrode layer is also provided on the side of the piezoelectric material layer away from the elastic carrier plate. This fourth electrode layer is also used to connect to the control circuit of the piezoelectric motor. The two electrodes on the piezoelectric material layer are connected to the first and fourth electrode layers, respectively, and are electrically connected to the control circuit through the first and fourth electrode layers. The two electrodes on the piezoelectric material layer are positive and negative electrodes, respectively. Therefore, one of the first and fourth electrode layers is a positive electrode layer, and the other is a negative electrode layer. Insulation is required between the first flange and the fourth electrode layer. This can be achieved by spacing the first flange and the fourth electrode layer, or by placing an insulating material (such as insulating adhesive) between them.

[0047] In one possible implementation, the piezoelectric ceramic includes a plurality of stacked piezoelectric material layers and a second electrode layer disposed between two adjacent piezoelectric material layers, the second electrode layer being electrically connected to electrodes of the same polarity on the two adjacent piezoelectric material layers.

[0048] With the same total thickness, multilayer piezoelectric ceramics have a higher piezoelectric constant D33 compared to single-layer piezoelectric ceramics, exhibiting better piezoelectric performance. Therefore, with the same excitation voltage, multilayer piezoelectric ceramics can produce greater deformation. Conversely, with the same degree of deformation, multilayer piezoelectric ceramics require a lower excitation voltage, meaning that a lower voltage can be used to excite multilayer piezoelectric ceramics while still providing the required driving force to the drive unit. In space-constrained applications, multilayer piezoelectric ceramics can be used as the inverse piezoelectric effect element of the drive unit. This eliminates the need for an additional boost circuit to increase the excitation voltage of the piezoelectric ceramic, simplifying the circuit structure and reducing its space occupation. This, in turn, reduces the size of the piezoelectric motor, and consequently, the size of the camera module and electronic equipment.

[0049] The second electrode layer is electrically connected to electrodes of the same polarity on two adjacent piezoelectric material layers. The second electrode layer between two adjacent piezoelectric material layers is shared. This can save the space occupied by the electrode layer in the piezoelectric ceramic, reduce the proportion of non-inverse piezoelectric material, and thus improve the piezoelectric performance of the piezoelectric ceramic.

[0050] In one possible implementation, a third electrode layer electrically connected to the piezoelectric material layer is disposed between the piezoelectric material layer and the elastic carrier plate. The piezoelectric material layer also has a second flange portion and a third flange portion connected to the third electrode layer on its side away from the elastic carrier plate. The second electrode layer with the same polarity as the third electrode layer is connected to the third flange portion, and the second electrode layer with the opposite polarity to the third electrode layer is connected to the third flange portion.

[0051] The second electrode layer is located between two adjacent piezoelectric material layers, and the third electrode layer is located between the piezoelectric material layer and the elastic carrier plate. Connecting these two layers to the control circuit is difficult. Therefore, a second and third flange are provided, which are extensions of the second and third electrode layers. This reduces the difficulty of connecting the second and third electrode layers to the control circuit and also improves the stability of the connection. This allows the piezoelectric ceramic to deform according to a preset pattern under the excitation of the AC signal from the control circuit, generating a stable thrust from the drive unit. This, in turn, provides a stable driving force for the piezoelectric motor. The movable lens barrel within the camera module moves smoothly under the stable drive of the piezoelectric motor, improving the focusing effect of the camera module and enabling the electronic device to capture higher-quality images or videos.

[0052] In one possible implementation, the elastic cantilever has at least two bending portions.

[0053] By increasing the number of bends on the elastic cantilever, its rigidity can be further reduced, thus enabling it to have greater flexibility compared to the drive body. This allows the elastic cantilever to mitigate the deformation of the drive body through its own deformation, reducing the impact of preload on the drive body's shape. For example, the elastic cantilever can have two, three, four, or even more bends.

[0054] In some examples, the number of bends on all elastic cantilever arms is the same. The flexibility of an elastic cantilever arm is related to the number of bends; the more bends, the lower the rigidity and the greater the flexibility. Setting the number of bends on all elastic cantilever arms to be the same ensures that the flexibility of each elastic cantilever arm is basically the same. When the drive unit is compressed, the degree of deformation of each elastic cantilever arm is also basically the same. This reduces the probability of the drive body tilting due to inconsistent deformation of the elastic cantilever arms on both sides, ensuring that the relative position between the drive unit and the internal friction plate of the piezoelectric motor meets the requirements and guarantees the contact stability of the two.

[0055] In one example, all the elastic cantilever arms and fixed parts are symmetrically arranged along the central axis of the drive body. This symmetrical arrangement of the elastic cantilever arms and fixed parts along the central axis of the drive body balances the forces on both sides of the drive body, reducing the probability of the drive body tilting due to deformation of the elastic cantilever arms.

[0056] In one example, the preload applied to the drive unit can act on the drive body, or it can be applied directly to the piezoelectric ceramic, with the preload transmitted to the drive protrusion through the piezoelectric ceramic and the elastic carrier plate, or it can be applied to the connecting plate, with the preload transmitted to the drive protrusion through the connecting plate; in another example, the preload applied to the drive unit can act on the fixing part, with the preload transmitted to the drive protrusion through the elastic cantilever and the elastic carrier plate.

[0057] In one possible implementation, the elastic carrier plate, the elastic cantilever, and the fixing part are integrally formed.

[0058] The integrated design of the elastic carrier plate, elastic cantilever, and fixing part can improve the connection strength between them, thereby enhancing the stability of the drive unit. This, in turn, allows the piezoelectric motor to have a more stable driving force, and the movable lens barrel within the camera module moves smoothly under the stable drive of the piezoelectric motor. This, in turn, helps improve the focusing effect of the camera module. In other examples, the elastic carrier plate, elastic cantilever, and fixing part can also be formed separately and then connected by welding.

[0059] In one example, the driving bump is hemispherical; in another example, the driving bump can also be semi-cylindrical.

[0060] Secondly, a piezoelectric motor is provided, including a friction plate and the aforementioned drive unit, wherein a drive protrusion of the drive unit abuts against the friction plate.

[0061] Because the driving body in the driving unit has a small degree of deformation in the initial state, the driving unit can deform in a preset manner under the action of alternating current, and the driving protrusion of the driving unit can move along a preset trajectory, thereby stably pushing the friction plate to move relative to the driving unit. Therefore, the piezoelectric motor in this example has high driving accuracy. Because the driving unit has low sensitivity to preload, its shape in the initial state is less affected by preload. Therefore, during the assembly process of the piezoelectric motor in this example, the control accuracy of preload can be appropriately relaxed. This can reduce the assembly difficulty of the piezoelectric motor, which is conducive to reducing its production cost and improving production efficiency.

[0062] In one possible implementation, the piezoelectric motor is further provided with a preload member, which abuts against the fixing part of the drive unit, and / or the preload member abuts against the drive body of the drive unit.

[0063] In one example, the preload component is pressed against the fixed part, that is, the preload is applied to the fixed part. The preload can be transmitted to the drive protrusion through the elastic cantilever and the elastic carrier plate. The drive body is not directly squeezed by the preload, thus reducing the impact of the preload on the shape of the drive body. The fixed part and the preload component can be fixed by welding or by adhesive bonding. Alternatively, a fixing hole can be provided on the fixed part and a threaded hole can be provided on the preload component. A fixing screw is screwed into the threaded hole through the fixing hole to achieve the connection. In this embodiment, the side of the drive body away from the friction plate can be free of any support structure. This allows the drive body to be approximately suspended, reducing the impact of external forces on the shape of the drive body, thereby improving the driving stability of the drive unit and the reliability of the piezoelectric motor. Since the side of the drive body away from the friction plate can be free of any support structure, the number of components inside the piezoelectric motor can be reduced, which is conducive to designing a smaller piezoelectric motor and reducing the space occupied by the piezoelectric motor. This can reduce the size of the camera module and the space occupied by the camera module in the electronic device, which is conducive to reducing the size and volume of the electronic device. In this example, the preload can also serve to fix the drive unit.

[0064] In one example, the pre-compression component is pressed against the drive body of the drive unit. Pressing the pre-compression component against the drive body of the drive unit applies pre-pressure to the drive body. This can be done by directly pre-compressing the piezoelectric ceramic, which is then transmitted to the drive protrusion through the piezoelectric ceramic and the elastic carrier plate, or by applying pre-pressure to the connecting plate. In this example, the pre-compression component is located between the drive unit and the inner wall of the housing. Thus, the pre-pressure on the drive unit can be adjusted by increasing the thickness of the pre-compression component. Since the pre-compression component is in direct contact with the drive body, and the drive body deforms when excited by an AC signal, the pre-compression component can have a certain degree of flexible buffering performance to accommodate the deformation of the drive body. For example, the second pre-compression component can be a buffer cotton, rubber pad, etc.

[0065] In one possible implementation, the piezoelectric motor is further provided with a control circuit, which is connected to all the piezoelectric ceramics on the drive unit, and the control circuit sends an electrical signal to one of the piezoelectric ceramics.

[0066] At any given moment, the control circuit of the piezoelectric motor only provides an electrical signal to one of the piezoelectric ceramics. Only one of the two piezoelectric ceramics on the drive unit is excited at any given time, i.e., unilateral excitation. Since unilateral excitation only connects an electrical signal to one piezoelectric ceramic on the drive unit at any given moment, the phase difference of the AC signal between the two piezoelectric ceramics is not involved in the circuit control. Therefore, using unilateral excitation, i.e., only connecting an electrical signal to one piezoelectric ceramic on the drive unit at any given moment, can reduce the difficulty of circuit control. On the other hand, since unilateral excitation does not involve the phase difference of the AC signal between the two piezoelectric ceramics in circuit control, the sensitivity of unilateral excitation to the drive unit assembly process is reduced, which can reduce the assembly difficulty of the drive unit, thus reducing the assembly difficulty of the piezoelectric motor and also improving the reliability of the piezoelectric motor.

[0067] Thirdly, a camera module is provided, including the aforementioned piezoelectric motor.

[0068] Because piezoelectric motors have high driving precision, camera modules using these piezoelectric motors have excellent focusing performance.

[0069] Fourthly, an electronic device is provided, including the aforementioned camera module.

[0070] Because the camera module has a high focusing effect, electronic devices that use this camera module can capture high-quality photos or videos.

[0071] In one possible implementation, the electronic device has a power supply module electrically connected to the piezoelectric motor, the power supply module providing an AC signal to the piezoelectric motor, the AC signal having a square waveform or a sine waveform.

[0072] Compared to sinusoidal AC signals, square-shaped AC signals have greater energy, which allows the driven bumps on the excited drive unit to have greater thrust. Attached Figure Description

[0073] Figure 1 is a schematic diagram of the structure of a piezoelectric motor in the related technology.

[0074] Figure 2 is a schematic diagram of the drive unit in Figure 1.

[0075] Figure 3 is a schematic diagram of the drive unit in Figure 1 under pressure bending.

[0076] Figure 4 is a schematic diagram of the electronic device structure provided in an embodiment of this application.

[0077] Figure 5 is a schematic diagram of the camera module structure provided in an embodiment of this application.

[0078] Figure 6 is a schematic diagram of the guide rail, slider, and piezoelectric motor structure provided in an embodiment of this application.

[0079] Figure 7 is a schematic diagram of the camera module structure provided in an embodiment of this application.

[0080] Figure 8 is a schematic diagram of the structure of the driving unit provided in an embodiment of this application.

[0081] Figure 9 is a schematic diagram of the drive unit shown in Figure 8 from another perspective.

[0082] Figure 10 is a schematic diagram of the structure of the elastic carrier plate provided in the embodiment of this application.

[0083] Figure 11 is a second schematic diagram of the structure of the driving unit provided in an embodiment of this application.

[0084] Figure 12 is a schematic diagram of the structure of the driving unit provided in the embodiment of this application.

[0085] Figure 13 is a second structural schematic diagram of the elastic carrier plate provided in an embodiment of this application.

[0086] Figure 14 is a schematic diagram of the first-order bending vibration mode of the symmetrical constraint of the driving unit shown in Figure 8.

[0087] Figure 15 is a schematic diagram of the region with zero amplitude under the first-order bending vibration mode shown in Figure 14.

[0088] Figure 16 is a schematic diagram of the first-order bending vibration mode of the antisymmetric constraint of the driving unit shown in Figure 8.

[0089] Figure 17 is a schematic diagram of the region with zero amplitude under the first-order bending vibration mode shown in Figure 16.

[0090] Figure 18 is a schematic diagram of the amplitude-frequency of the driving unit provided in the embodiment of this application.

[0091] Figure 19 is a schematic diagram of the harmonic response modes of the fixed part of the drive unit shown in Figure 8 in the free state.

[0092] Figure 20 is a schematic diagram of the constrained harmonic response modes of the fixed part of the drive unit shown in Figure 8.

[0093] Figure 21 is a schematic diagram of the structure of the elastic carrier plate shown in Figure 13.

[0094] Figure 22 is a top view of the drive unit shown in Figure 8.

[0095] Figure 23 is a modal diagram of the drive unit shown in Figure 8 under preload conditions.

[0096] Figure 24 is a schematic diagram of the structure of the driving unit provided in the embodiment of this application.

[0097] Figure 25 is a schematic diagram of the structure of the driving unit provided in the embodiment of this application.

[0098] Figure 26 is a schematic diagram of the structure of the driving unit provided in the embodiment of this application.

[0099] Figure 27 is a schematic diagram of the structure of the driving unit provided in the embodiment of this application.

[0100] Figure 28 is a schematic diagram of the structure of the driving unit provided in the embodiment of this application.

[0101] Figure 29 is a schematic diagram of the structure of the driving unit provided in an embodiment of this application.

[0102] Figure 30 is a schematic diagram of the structure of the driving unit provided in an embodiment of this application.

[0103] Figure 31 is a schematic diagram of the drive unit and friction plate provided in an embodiment of this application.

[0104] Figure 32 is a schematic diagram of the structure of the driving unit provided in an embodiment of this application.

[0105] Figure 33 is a bottom view of the drive unit shown in Figure 32.

[0106] Figure 34 is a schematic diagram of the structure of the multilayer piezoelectric ceramic provided in the embodiment of this application.

[0107] Figure 35 is a schematic diagram of the front cross-sectional structure of the piezoelectric motor provided in an embodiment of this application.

[0108] Figure 36 is a side sectional view of the outer shell and friction plate in Figure 35.

[0109] Figure 37 is a second schematic diagram of the front cross-sectional structure of the piezoelectric motor provided in an embodiment of this application.

[0110] Figure 38 is a schematic diagram of the single-sided excitation mode of the driving unit shown in Figure 8.

[0111] Figure 39 is a schematic diagram of a square waveform provided in an embodiment of this application.

[0112] Reference numerals: 1', Elastic carrier plate; 2', Piezoelectric ceramic; 3', Drive protrusion; 4', Fixing part; 5', Friction plate; 10000, Electronic device; 1000, Camera module; 2000, Back cover; 3000, Display screen; 4000, Frame; 100, Lens; 200, Fixed lens barrel; 300, Movable lens barrel; 400, Piezoelectric motor; 500, Filter; 610, Guide rail; 620, Slider; 710, Guide groove; 720, Ball bearing; 800, Image sensor; 900, Base; 10, Drive unit; 20, Friction plate; 30, Housing; 40, Pre-compression component; 1. Driving body; 11. Elastic carrier plate; 111. First excitation plate; 1111. First side surface; 112. Second excitation plate; 1121. Second side surface; 113. Connecting plate; 1131. Third side surface; 114. Plate body; 115. Extension; 1151. Fourth side surface; 12. Piezoelectric ceramic; 121. Piezoelectric material layer; 121A. Material layer A; 121B. Material layer B; 121C. Material layer C; 121D, Material layer D; 122, First electrode layer; 123, First flange; 124, Second flange; 126, Third flange; 127, Second electrode layer; 127A, Electrode layer A; 127B, Electrode layer B; 127C, Electrode layer C; 128, Third electrode layer; 129, Fourth electrode layer; 13, Driving protrusion; 141, First edge surface; 142, Second edge surface; 143, Third edge surface; 2, Elastic cantilever; 21, Bending part; 3, Fixing part; 31, Fixing hole; 4, Connecting arm. Detailed Implementation

[0113] For ease of understanding, the technical terms used in this application will be explained and described below.

[0114] Lens: A component that uses the refraction principle of a lens to allow light from a scene to pass through the lens and form a clear image on the focal plane.

[0115] Optical axis (OA): The direction in which light rays travel through an optical system, referenced to the principal ray at the center of the field of view. For symmetrical transmission systems, it generally coincides with the rotation center line of the optical system. For off-axis and reflective systems, the optical axis may appear as a broken line.

[0116] Focal length, also known as focal length, is a measure of the convergence or divergence of light in an optical system. It refers to the distance from the optical center of a lens or lens group to the focal point when a distant object is projected into a sharp image on the focal plane. It can also be understood as the perpendicular distance from the optical center of the lens or lens group to the focal plane. From a practical perspective, it can be understood as the distance from the center of the lens to the image plane.

[0117] Focusing: Focusing, also known as light focusing or focusing, is the process of changing the position of the object distance and the camera lens distance through the camera's focusing mechanism to make the subject appear sharp. Digital cameras typically have multiple focusing modes, such as autofocus, manual focus, or multiple focus modes.

[0118] Object side and image side: With the lens as the boundary, the side where the object is located is called the object side, and the surface of the lens closest to the object side can be called the object side surface; with the lens as the boundary, the side where the image of the object is located is called the image side, and the surface of the lens closest to the image side can be called the image side surface.

[0119] Piezoelectric ceramics are polycrystalline materials that exhibit piezoelectric effects. They are named for their production process, which is similar to that of ceramics (raw material crushing, molding, and high-temperature sintering). Common piezoelectric ceramic materials include barium titanate, lead titanate, lead zirconate titanate, titanium magnesium niobate, and potassium sodium niobate.

[0120] The inverse piezoelectric effect refers to the mechanical deformation or stress that occurs when an electric field is applied in the polarization direction of a dielectric material. When the applied electric field is removed, the deformation or stress disappears.

[0121] First-order bending vibration mode: This is the bending vibration mode that occurs when the excitation frequency of the external force is equal to the natural frequency (first order) of the object.

[0122] Symmetric constraints: Symmetric constraints refer to the fact that the geometry, boundary conditions, material properties, and loads of the analyzed object are symmetrical about a certain plane.

[0123] Antisymmetric constraint: An antisymmetric constraint means that the geometry, boundary conditions, and material properties of the analyzed object are symmetric about a certain surface, while the load is antisymmetric about that surface.

[0124] Nodes: also known as wave nodes, refer to the positions where the modal values ​​are zero. In other words, in mode shape animation, the stationary points are nodes, which are also the intersection points of the modal shape and the original undeformed structure. Moreover, the node positions are different for each mode.

[0125] Nodal line: refers to a line composed of nodes, meaning that the modal values ​​are all zero on this line.

[0126] Harmonic response: used to determine the steady-state response of a linear structure under a load that varies sinusoidally (harmonically) over time. The analysis only calculates the steady-state forced vibration of the structure and does not consider the transient vibration at the start of excitation. The purpose of harmonic response analysis is to calculate the response value (usually displacement) of the structure at several frequencies as a function of frequency, so that designers can predict the continuous dynamic characteristics of the structure and verify whether the design can overcome the harmful effects caused by resonance, fatigue and other forced vibrations.

[0127] Power-to-weight ratio: refers to the ratio between the thrust generated by a device or equipment and its weight; the calculation formula is: power-to-weight ratio = thrust / weight, where the units of thrust and weight are Newtons (N) and kilograms (kg), respectively.

[0128] Frequency window: If a driving unit can generate driving thrust when excited by a frequency within a certain range, then that frequency range is called the frequency window.

[0129] Alternating current (AC): refers to current whose direction changes periodically with time, and whose average current is zero over one cycle.

[0130] Electric field: It is a special kind of substance that exists in the space surrounding electric charge and changing magnetic field. This substance is different from ordinary matter. Although it is not composed of molecules and atoms, it is an objectively existing special substance that has the objective properties of force and energy that ordinary matter has.

[0131] With the continuous development of portable electronic devices such as mobile phones, users have increasingly higher requirements for the image quality of electronic devices. Focusing performance is one of the factors affecting the image quality of electronic devices. At present, most camera modules of electronic devices use voice coil motors, piezoelectric motors and other driving devices to drive the movable lens barrel in the module to achieve the focusing function.

[0132] Compared to voice coil motors, piezoelectric motors are increasingly being used due to their advantages such as high power density, small size, no magnetic interference, and self-locking capability when power is off.

[0133] Piezoelectric motors contain piezoelectric ceramic materials. These ceramics, after polarization, produce the piezoelectric effect. Specifically, when a piezoelectric ceramic is deformed under an external force in a certain direction, polarization occurs within it, resulting in opposite charges appearing on its two opposing surfaces. When the external force is removed, it returns to its uncharged state; this phenomenon is called the direct piezoelectric effect. The polarity of the charge changes when the direction of the force changes. In short, the electrical effect produced by the deformation of a piezoelectric ceramic under stress is called the direct piezoelectric effect.

[0134] Conversely, when an electric field is applied in the polarization direction of a piezoelectric ceramic, the ceramic will deform. Once the electric field is removed, the deformation disappears. This phenomenon is called the inverse piezoelectric effect. In short, the effect of a piezoelectric ceramic deforming due to an applied voltage is called the inverse piezoelectric effect.

[0135] Because piezoelectric ceramics possess both the direct and inverse piezoelectric effects, they have become a type of functional material capable of converting mechanical energy into and vice versa. The applications of piezoelectric ceramics are extremely wide-ranging, from space exploration to everyday life, resulting in a diverse array of functional products. Products utilizing the direct piezoelectric effect include microphones, igniters, piezoelectric sensors (touch sensors), pressure sensors, and gyroscopes. Products utilizing the inverse piezoelectric effect include piezoelectric motors, buzzers, underwater acoustic transducers, filters, and resonators.

[0136] Figure 1 is a structural schematic diagram of a piezoelectric motor in the related art, and Figure 2 is a structural schematic diagram of the drive unit in Figure 1. As shown in Figures 1 and 2, the piezoelectric motor includes a drive unit and a friction plate 5'. The drive unit includes an elastic carrier plate 1', a piezoelectric ceramic 2' disposed on the back of the elastic carrier plate 1', a drive protrusion 3' disposed in the center of the front of the elastic carrier plate 1', and a fixing part 4' disposed on the edge of the elastic carrier plate 1'. The fixing part 4' is used to install and fix the drive unit to provide support for the drive unit.

[0137] In the initial state, a pre-pressure is required to press the driving protrusion 3' and the friction plate 5' tightly together, so that the driving protrusion 3' and the friction plate can form a squeezing force to generate friction. Under the action of the alternating electric field, the deformation of the piezoelectric ceramic 2' due to the inverse piezoelectric effect will cause the elastic carrier plate 1' to deform, thereby driving the driving protrusion 3' to produce a circular or elliptical trajectory perpendicular to the surface of the elastic carrier plate 1'. Taking the direction shown in Figure 1 as an example, when the driving protrusion 3' moves in the clockwise direction, when the driving protrusion 3' moves towards... During the downward circular motion to the lowest point, the driving protrusion 3' gradually separates from the friction plate 5'. As the driving protrusion 3' moves upward in a circular motion to the highest point, it re-engages with the friction plate 5' and compresses it. The friction between the driving protrusion 3' and the friction plate 5' pushes the friction plate 5' to the right. When the driving protrusion 3' moves counterclockwise, the friction between the driving protrusion 3' and the friction plate 5' pushes the friction plate 5' to the left. The friction plate 5' is connected to the movable lens barrel within the camera module. Thus, the movement of the friction plate 5' during its motion drives the movable lens barrel to achieve focusing.

[0138] However, due to issues such as insufficient precision in the assembly process, the magnitude of the pre-pressure that presses the drive protrusion 3' and the friction plate 5' together may vary. Figure 3 is a schematic diagram of the bending of the drive unit in Figure 1 under pressure. As shown in Figure 3, under the action of pre-pressure, the middle part of the drive unit is subjected to the interaction force F' provided by the friction plate 5'. Combined with the characteristics of the elastic carrier plate 1' being suspended on the back and fixed by the fixing part 4' on all sides, the interaction force F' easily causes the elastic carrier plate 1' to bend and deform. The magnitude of the interaction force F' is related to the pre-pressure. Thus, when the magnitude of the pre-pressure changes, the degree of deformation of the elastic carrier plate 1' will also change. For example, when the pre-pressure increases, the elastic carrier plate 1' will bend more. The deformation of the elastic carrier plate 1' will affect the shape of the piezoelectric ceramic 2' in the initial state, causing the piezoelectric ceramic 2' to also be bent in the initial state. Then, the actual deformation shape of the piezoelectric ceramic 2' under the action of the alternating electric field is inconsistent with the designed deformation shape, which in turn causes the trajectory of the drive bump 3' to be inconsistent with the designed trajectory, resulting in poor driving accuracy. This will further affect the focusing effect of the camera module.

[0139] Based on this, embodiments of this application provide a driving unit, a piezoelectric motor, a camera module, and an electronic device, which have high driving accuracy and can improve the focusing effect of the camera module.

[0140] This application first provides an electronic device, which may be, for example, a mobile phone, tablet computer, laptop computer, television set, in-vehicle equipment, wearable device, personal digital assistant (PDA), point of sale (POS), camera, video surveillance equipment, or other electronic products with photography or video recording functions. The mobile phone may be, for example, a conventional candybar phone or a foldable phone, such as a small vertical folding phone, a left-right inward folding phone, or a left-right outward folding phone. Wearable devices may be, for example, smart bracelets, smartwatches, wireless headphones, augmented reality (AR) glasses, AR headsets, virtual reality (VR) glasses, or VR headsets. This application embodiment uses a mobile phone as an example for explanation.

[0141] Figure 4 is a structural schematic diagram of the electronic device 10000 provided in an embodiment of this application. Referring to Figure 4, the electronic device 10000 includes a camera module 1000, a back cover 2000, a display screen 3000, a frame 4000, and an image processor located inside the device. The back cover 2000 and the display screen 3000 are respectively fixed to both sides of the frame 4000, and the back cover 2000, the display screen 3000, and the frame 4000 together enclose the entire internal cavity of the electronic device 10000.

[0142] The display screen 3000 can be used to display images and can also integrate touch functionality for human-computer interaction. The camera module 1000 is housed within the overall cavity of the device. The camera module 1000 is used to acquire optical information from the outside of the electronic device 10000 and form corresponding image signals. The image processor is communicatively connected to the camera module 1000. The image processor acquires and processes the image signals from the camera module 1000. The communication connection between the camera module 1000 and the image processor can include data transmission via electrical connections such as wiring, or data transmission via coupling. It is understood that the camera module 1000 and the image processor can also communicate via other methods capable of data transmission.

[0143] In some examples, the back cover 2000 may have a camera aperture through which the camera module 1000 collects light. The camera module 1000 can be used as a rear camera of the electronic device 10000. Exemplarily, the back cover 2000 may include a light-transmitting lens mounted on the camera aperture to allow light to pass through and to provide dust and water resistance. This light-transmitting lens can also be considered part of the camera module 1000 in some cases. For example, this light-transmitting lens can be any of the light-transmitting lenses shown in Figure 4.

[0144] In some examples, the camera module 1000 can also serve as a front-facing camera for the electronic device 10000. For instance, the display screen 3000 may have a light-transmitting area, through which the camera module 1000 can capture optical information from the outside of the electronic device 10000. That is, the camera module 1000 can be used as a front-facing camera module 10000 for the electronic device 10000, or as a rear-facing camera module 10000 for the electronic device 10000; this embodiment of the application does not impose strict limitations on this.

[0145] In practical applications, the electronic device 10000 may have one camera module 1000, that is, only include the camera module 1000, or it may have two, three, four, five or more camera modules 1000, including the camera module 1000. When there are multiple camera modules 1000, these multiple camera modules 1000 can be arranged on the side of the electronic device 10000 in a certain way. For example, one or more of them may be set on the front side where the display screen 3000 is located, and used as a front-facing camera, while the remaining one or more camera modules 1000 may be set on the back cover 2000, and used as a rear-facing camera.

[0146] In some examples, electronic device 10000 may include one or more of the following: a front-facing camera (module), a rear-facing camera, a main camera lens, a secondary camera lens, a telephoto lens, an ultra-wide-angle lens, a macro lens, or a depth-of-field lens, and camera module 1000 may be any of the aforementioned lenses.

[0147] In some examples, the electronic device 10000 may also include an analog-to-digital converter (also known as an A / D converter, not shown in the figure). The analog-to-digital converter is connected between the camera module 1000 and the image processor. The analog-to-digital converter is used to convert the analog image signal generated by the camera module into a digital image signal and transmit it to the image processor. The image processor then processes the digital image signal to obtain a processed image signal, which can be displayed as an image or video on the display screen 3000.

[0148] In some examples, the electronic device 10000 may also include a memory (not shown) communicatively connected to an image processor. The image processor transmits processed image signals to the memory so that the processed image signals can be retrieved from the memory and displayed on the display screen 3000 when the image needs to be viewed later. In some embodiments, the image processor may also compress the processed image signals before storing them in the memory to save memory space.

[0149] Figure 5 is a schematic diagram of the structure of the camera module 1000 provided in this embodiment of the application. Referring to Figure 5, the camera module 1000 provided in this embodiment of the application is disposed in the inner cavity of the device, and includes an optical lens and an image sensor 800. The image sensor 800 is located on the image side of the optical lens. Light passes through the fixed lens barrel 200 and the movable lens barrel 300 along the optical axis in sequence, and is recognized by the image processor inside the device. The camera module 1000 may also include a circuit board (not shown in the figure), and the image sensor 800 may be disposed on the circuit board. Light can pass through the optical lens and illuminate the image sensor 800. Exemplarily, the working principle of the camera module 1000 is as follows: the light reflected from the subject passes through the optical lens to generate an optical image, which is projected onto the image sensor 800. The image sensor 800 converts the optical image into an electrical signal, i.e., an analog image signal, and transmits it to the analog-to-digital converter, so that the analog-to-digital converter converts it into a digital image signal for the image processor.

[0150] The image sensor 800 (also known as a photosensitive element) is a semiconductor chip containing hundreds of thousands to millions of photodiodes on its surface. When illuminated, these photodiodes generate electrical charges. The image sensor 800 can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) sensor. CCDs are made using a highly sensitive semiconductor material that converts light into electrical charges. They consist of many photosensitive units, typically measured in megapixels. When the surface of the CCD (the photosensitive surface) is illuminated, each photosensitive unit reflects a charge onto the component. The signals generated by all the photosensitive units are added together to form a complete image. CMOS sensors primarily utilize silicon and germanium, creating a semiconductor structure where N-polar and P-polar semiconductors coexist. The current generated by these complementary effects can be recorded and interpreted by the processing chip as an image.

[0151] In some examples, the image sensor 800 can move in a plane perpendicular to the thickness direction of the camera module 1000 or tilt relative to the thickness direction of the camera module 1000 to achieve image stabilization. In this case, the image sensor 800 does not have the ability to move in the direction parallel to the thickness of the camera module 1000, or has a very small travel distance much smaller than the focusing stroke, to reduce the module thickness. In other embodiments, the image sensor 800 may also be a fixed component and therefore cannot perform shake compensation.

[0152] In some examples, as shown in Figure 5, the camera module 1000 also includes a filter 500. The filter 500 can be located between the optical lens and the image sensor 800 to filter out unwanted wavelengths of light, preventing the image sensor 800 from producing false colors or ripples, thereby improving its effective resolution and color reproduction. Exemplarily, the filter 500 can be an infrared filter, such as an infrared radiation-cut filter (IRCF). In this embodiment, the filter 500 is a separate component located between the optical lens and the image sensor 800. In other embodiments, the filter 500 can be positioned anywhere before the image sensor 800, or the filter 500 can be omitted entirely, and filtering can be achieved by surface treatment or material treatment of at least one optical element of the optical lens. This application does not strictly limit the specific embodiments of the structure or component used to achieve filtering.

[0153] For example, filter 500 can be achieved by vapor-depositing an infrared (IR) material coating onto a sapphire substrate.

[0154] For example, filter 500 can be a white glass filter or a blue glass filter, etc.

[0155] Referring again to Figure 5, the optical lens includes a fixed lens barrel 200 and a movable lens barrel 300. A safe distance is formed between the fixed lens barrel 200 and the movable lens barrel 300 to ensure that there is no collision between the optical elements during the focusing process of the optical lens. Several lenses 100 are provided in both the fixed lens barrel 200 and the movable lens barrel 300. The lenses 100 can be convex or concave. The several lenses 100 respectively form a fixed lens barrel 200 and a movable lens barrel 300 with different focal lengths. The focal length of the optical lens barrel can be adjusted by adjusting the distance between the fixed lens barrel 200 and the movable lens barrel 300, so as to achieve focusing of the camera module 1000.

[0156] The fixed lens barrel 200 can be fixed on the base 900 inside the equipment cavity, and the movable lens barrel 300 can be slidably disposed on the base 900. It should be noted that the optical axes of the fixed lens barrel 200 and the movable lens barrel 300 need to be coaxial, and the moving direction of the movable lens barrel 300 needs to be parallel to the optical axis, so as to ensure the coaxiality of the movable lens barrel 300 and the fixed lens barrel 200 during the movement. Figure 6 is a schematic diagram of the structure of the guide rail 610, the slider 620 and the piezoelectric motor 400 provided in the embodiment of this application. Referring to Figure 6, in some embodiments, the base 900 can be... A fixed guide rail 610 is provided, the length of which extends along the optical axis. A slider 620 is provided on the guide rail 610, and the slider 620 carries the movable lens barrel 300. The movable lens barrel 300 is limited in its direction of movement by the guide rail 610 and the slider 620, thereby ensuring the coaxiality of the movable lens barrel 300 with the fixed lens barrel 200 during movement. Of course, in some embodiments, the positions of the guide rail 610 and the slider 620 can be interchanged, that is, the slider 620 is fixed to the base 900, and the guide rail 610 is connected to the movable lens barrel 300, with the guide rail 610 carrying the movable lens barrel 300.

[0157] In some embodiments, continuing to refer to FIG6, the piezoelectric motor 400 of the camera module 1000 is connected to the slider 620. The piezoelectric motor 400 drives the movable lens barrel 300 to move through the slider 620 to adjust the position of the movable lens barrel 300 and realize the focusing function of the camera module 1000. The piezoelectric motor 400 includes a drive unit 10 and a friction plate 20. The drive unit 10 is fixedly set, while the friction plate 20 is movably set and can move relative to the drive unit 10. In the embodiments of this application, the drive unit 10 is fixed to the base 900, and the friction plate 20 is fixed to the slider 620. Under the action of the alternating current signal, the drive unit 10 deforms due to the inverse piezoelectric effect, and friction is generated between the drive unit 10 and the friction plate 20, thereby causing the friction plate 20 to move along the length direction of the guide rail 610, and then driving the slider 620 to move, thereby realizing the position adjustment of the movable lens barrel 300 and realizing the focusing function of the camera module 1000. Of course, the connection method between the piezoelectric motor 400, the base 900, and the slider 620 is not unique. In other embodiments, the drive unit 10 can be fixed to the slider 620, and the friction plate 20 can be fixed to the base 900.

[0158] In other embodiments, the movable lens barrel 300 can also be guided by a structure other than a guide rail-slider; Figure 7 is a second schematic diagram of the camera module 1000 provided in an embodiment of this application. Referring to Figure 7, a guide groove 710 can be provided in the base 900, and a ball bearing 720 can be provided in the guide groove 710. The ball bearing 720 can be connected to the movable lens barrel 300, or the ball bearing 720 can be connected to the guide groove 710. The movable lens barrel 300 is limited in its direction of movement by the guide groove 710 and the ball bearing 720, which can also ensure that the movable lens barrel 300 moves in a certain direction. During the process, the coaxiality with the fixed lens barrel 200 is maintained; when the movable lens barrel 300 moves, the ball bearing 720 can rotate, which also reduces the friction between the movable lens barrel 300 and the base 900; in this embodiment, the piezoelectric motor 400 can be directly connected to the movable lens barrel 300. For example, the drive unit 10 of the piezoelectric motor 400 can be fixed to the inner wall of the device, and the friction plate 20 can be fixed to the movable lens barrel 300, or the drive unit 10 of the piezoelectric motor 400 can be fixed to the movable lens barrel 300, and the friction plate 20 can be fixed to the base 900.

[0159] The embodiments of this application mainly involve structural improvements to the driving unit 10. The structure of the driving unit 10 will be described in detail below with reference to the accompanying drawings.

[0160] Figure 8 is a structural schematic diagram of the drive unit 10 provided in an embodiment of this application. Figure 9 is a structural schematic diagram of the drive unit 10 shown in Figure 8 from another perspective. Referring to Figures 8 and 9, the drive unit 10 includes a fixing part 3, an elastic cantilever 2, and a drive body 1. The drive body 1 includes an elastic carrier plate 11 and a drive protrusion 13 and a piezoelectric ceramic 12 disposed on the elastic carrier plate 11. The elastic cantilever 2 is provided with a bending part 21. The fixing part 3 and the drive body 1 are connected through the elastic cantilever 2. The fixing part 3 is used to support the elastic cantilever 2 and the drive body 1.

[0161] By providing a bending portion 21 on the elastic cantilever 2, the rigidity of the elastic cantilever 2 can be reduced, thereby increasing the flexibility of the elastic cantilever 2. This makes the elastic cantilever 2 more easily deformed under the action of external force. Using the elastic cantilever 2 with the bending portion 21 to connect the fixing portion 3 to the driving body 1, when the preload is applied to the driving unit 10, the elastic cantilever 2 can deform, thereby reducing the degree of deformation of the driving body 1 and reducing the influence of the preload on the shape of the driving body 1. That is, reducing the influence of the magnitude of the preload on the degree of deformation of the driving body 1, which also reduces the sensitivity of the driving body 1 to the preload. This is beneficial for the driving unit 10 to deform in a preset manner under the action of alternating current, thereby enabling the piezoelectric motor 400 to have higher driving accuracy, thereby improving the focusing effect of the camera module 1000 and enabling the electronic device 10000 to capture higher quality images or videos.

[0162] In this embodiment, the fixing part 3 is fixed to the components inside the piezoelectric motor 400 used for mounting the drive unit 10. That is, the drive unit 10 is mounted to the components inside the piezoelectric motor 400 used for mounting the drive unit 10 through the fixing part 3. In this way, the components inside the piezoelectric motor 400 used for mounting the drive unit 10 provide support for the elastic cantilever 2 and the drive body 1 of the drive unit 10 through the fixing part 3.

[0163] Referring again to Figures 8 and 9, the elastic carrier plate 11 includes a first excitation plate 111 and a second excitation plate 112 spaced apart, and a connecting plate 113 connecting the first excitation plate 111 and the second excitation plate 112. A driving protrusion 13 is disposed on the connecting plate 113, and both the first excitation plate 111 and the second excitation plate 112 are provided with piezoelectric ceramics 12. By providing piezoelectric ceramics 12 on both the first excitation plate 111 and the second excitation plate 112, the first excitation plate 111 and the second excitation plate 112 can respectively generate deformation, and the bending deformation of the first excitation plate 111 and the second excitation plate 112 can be transmitted to the connecting plate 113, thereby causing the driving protrusion 13 to generate a circular or elliptical trajectory perpendicular to the surface of the elastic carrier plate 11.

[0164] In this embodiment, the first excitation plate 111 and the second excitation plate 112 are parallel, and the connecting plate 113 is perpendicular to the first excitation plate 111 and the second excitation plate 112; in some embodiments, the connecting plate 113 may not be perpendicular to the first excitation plate 111 and the second excitation plate 112, that is, the included angle between the connecting plate 113 and the first excitation plate 111 and the second excitation plate 112 is an acute angle or an obtuse angle.

[0165] In some embodiments, each excitation plate is provided with piezoelectric ceramic 12 on only one side, that is, the first excitation plate 111 is provided with piezoelectric ceramic 12 on only one side, and the second excitation plate 112 is provided with piezoelectric ceramic 12 on only one side. The piezoelectric ceramic 12 and the driving protrusion 13 can be located on the same side of the elastic carrier plate 11, or they can be located on opposite sides of the elastic carrier plate 11. In other embodiments, piezoelectric ceramic 12 can be provided on both sides of each excitation plate, that is, piezoelectric ceramic 12 is provided on both sides of the first excitation plate 111, and piezoelectric ceramic 12 is also provided on both sides of the second excitation plate 112.

[0166] In this embodiment, the piezoelectric ceramic 12 needs to be connected to the control circuit (not shown in the figure) inside the piezoelectric motor 400 to realize the energization and excitation of the piezoelectric ceramic 12. By setting the piezoelectric ceramic 12 only on one side of the excitation plate, the number of piezoelectric ceramics 12 in the drive unit 10 can be reduced, which simplifies the circuit connection structure inside the piezoelectric motor 400. If the piezoelectric ceramic 12 is set on both sides of the excitation plate, both sides of the excitation plate can be subjected to the deformation force generated by the piezoelectric ceramic 12 when energized, which can enhance the deformation amplitude of the drive unit 10, thereby making the drive protrusion 13 have a greater thrust.

[0167] In this embodiment, the piezoelectric ceramic 12 has the same shape and size as the excitation plate, meaning that the piezoelectric ceramic 12 completely covers the side of the excitation plate. Since the driving body 1 does not deform much or deforms little under pre-pressure, the piezoelectric ceramic 12 also deforms little under pre-pressure. Furthermore, changes in the pre-pressure have little impact on the deformation of the driving unit 10. Therefore, even if the pre-pressure is increased, the piezoelectric ceramic 12 will not deform significantly. Consequently, the risk of the piezoelectric ceramic 12 breaking due to pre-pressure is reduced.

[0168] Figure 10 is a schematic diagram of the structure of the elastic carrier plate 11 provided in an embodiment of this application. Referring to Figure 10, the first excitation plate 111, the second excitation plate 112, and the connecting plate 113 are connected to form a U-shaped first edge surface 141, and at least one of the elastic cantilever arms 2 is connected to the first edge surface 141. In this embodiment, there is a void area around the first edge surface 141. When the elastic cantilever arm 2 is connected to the first edge surface 141, a portion of the elastic cantilever arm 2 will be located within this void area, which can reduce the size of the elastic cantilever arm 2 protruding from the driving body 1. This can reduce the size of the driving unit 10 and the space occupied by the driving unit 10, thereby appropriately reducing the size of the piezoelectric motor 400, and further reducing the space occupied by the camera module 10000 on the electronic device 10000, which is beneficial to reducing the size of the electronic device 10000.

[0169] The side of the first excitation plate 111 that is close to the second excitation plate 112 is called the first side 1111, the side of the second excitation plate 112 that is close to the first excitation plate 111 is called the second side 1121, and the side of the connecting plate 113 that is connected to the first side 1111 and the second side 1121 is called the third side 1131. In this embodiment, the first side 1111, the second side 1121 and the third side 1131 are connected to form a U-shaped first edge surface 141.

[0170] Figure 11 is a second structural schematic diagram of the drive unit 10 provided in the embodiment of this application. Referring to Figure 11, the drive unit 10 has a plurality of elastic cantilever arms 2. Among them, a portion of the elastic cantilever arms 2 can be connected to one side of the first excitation plate 111 facing the second excitation plate 112, that is, the elastic cantilever arms 2 are connected to the first side 1111. Another portion of the elastic cantilever arms 2 can be connected to one side of the second excitation plate 112 facing the first excitation plate 111, that is, the elastic cantilever arms 2 are connected to the second side 1121.

[0171] Figure 12 is a schematic diagram of the structure of the drive unit 10 provided in the embodiment of this application. Referring to Figure 12, the elastic cantilever 2 can also be connected to the side of the connecting plate 113, that is, the elastic cantilever 2 is connected to the third side 1131.

[0172] Figure 13 is a second structural schematic diagram of the elastic carrier plate 11 provided in the embodiment of this application. Referring to Figure 13, the connecting plate 113 includes a plate body 114 connecting the first excitation plate 111 and the second excitation plate 112. Both sides of the plate body 114 extend in a direction away from the center of the plate body 114 to form extension portions 115. The extension portions 115 are located between the first excitation plate 111 and the second excitation plate 112. The driving protrusion 13 is disposed on the plate body 114.

[0173] Figure 14 is a schematic diagram of the first-order bending vibration mode of the symmetrically constrained driving unit 10 shown in Figure 8; Figure 15 is a schematic diagram of the region with zero amplitude in the first-order bending vibration mode shown in Figure 14; Figure 16 is a schematic diagram of the first-order bending vibration mode of the antisymmetrically constrained driving unit 10 shown in Figure 8; Figure 17 is a schematic diagram of the region with zero amplitude in the first-order bending vibration mode shown in Figure 16; wherein, the values ​​corresponding to the scale bars in Figures 14 and 16 are the amplitudes of the driving unit 10, in micrometers (μm); the shaded area in Figure 15 corresponds to the region with zero amplitude in the mode of Figure 14; the shaded area in Figure 17 corresponds to the region with zero amplitude in the mode of Figure 16; it should be noted that, in this embodiment, two AC signals with zero phase difference are used to excite the two piezoelectric ceramics of the driving unit 10 respectively. 12. The mode shown in Figure 14 can be obtained; by using two AC signals with a phase difference of 180° to excite the two piezoelectric ceramics 12 of the driving unit 10 respectively, the mode shown in Figure 16 can be obtained; in fact, the natural frequency (first order) of the driving unit 10 is affected by the excitation method. That is to say, the natural frequency (first order) of the driving unit 10 under symmetric constraint (Figure 14) and antisymmetric constraint (Figure 16) is different. Figure 18 is a schematic diagram of the amplitude-frequency of the driving unit 10 provided in the embodiment of this application. Taking Figure 18 as an example, the horizontal axis of Figure 18 represents the frequency f of external force excitation, and the vertical axis represents the amplitude d of the driving unit 10. In some embodiments, the first order frequency of the driving unit 10 under symmetric constraint (Figure 14) is f1, and the first order frequency under antisymmetric constraint (Figure 16) is f2, f1≠f2.

[0174] Figure 19 is a schematic diagram of the harmonic response mode of the fixed part 3 of the drive unit 10 shown in Figure 8 in the free state. By using two AC signals with a phase difference of 90° to excite the two piezoelectric ceramics 12 of the drive unit 10 respectively, the mode shown in Figure 19 can be obtained. In Figure 19, the values ​​corresponding to the scales are the amplitudes of the drive unit 10, and the units are micrometers (μm). In actual operation, by using two AC signals with a phase difference of 90° to excite the two piezoelectric ceramics 12 of the drive unit 10 respectively, the drive bump 13 can be made to perform trajectory movement.

[0175] In this embodiment, the extensions 115 on both sides of the plate body 114 are symmetrically arranged.

[0176] The extension 115 alters the shape of the drive unit 10, thus affecting the natural frequency (first order) of the drive unit 10. Specifically, the extension 115 affects the first-order modal frequencies f1 and f2 of the drive unit 10 under symmetric and antisymmetric constraints. Referring to Figure 13, the distance between the ends of the two extensions 115 is W1. The larger W1 is, the larger the modal frequencies f1 under symmetric constraints and f2 under antisymmetric constraints of the drive unit 10; conversely, the smaller W1 is, the smaller f1 and f2 are. The dimensions of the plate body 114 also affect f1 and f2. Continuing to refer to Figure 13, the width of the plate body 114 is W2. The larger W2 is, the smaller f1 is; conversely, the smaller W2 is, the larger f1 is, while f2 is almost unaffected by W2. Continuing to refer to Figure 13, the width of the extension 115 is L1, and the length of the plate body 114 is L2. L1 and L2 have a coupled effect on f1 and f2. Therefore, the extension 115 can adjust the first-order frequency of the drive unit 10 under symmetric and antisymmetric constraints to a certain extent, so that the first-order frequencies f1 and f2 of the drive unit 10 under these two constraints are as close as possible.

[0177] Therefore, the extension 115 can adjust the values ​​of f1 and f2 by adjusting its own shape, thereby reducing the range between f1 and f2. In actual operation, a frequency within the range of f1 to f2 can be selected to actually excite the two piezoelectric ceramics 12. For example, the frequency f0 in Figure 18 can be selected, and the phase difference between the two AC signals can be set to 90° to excite the mode shown in Figure 19. This makes the trajectory of the driving protrusion 13 approach a circle or ellipse, thereby making the driving protrusion 13 have a more balanced thrust to push the friction plate 20 to move. That is, the setting of the extension 115 can optimize the movement trajectory of the driving protrusion 13, so that the driving protrusion 13 can push the friction plate 20 to move more stably, thereby making the piezoelectric motor 400 have a stable driving force. The movable lens barrel 300 in the camera module 1000 is stably driven by the piezoelectric motor 400 and moves smoothly. This is beneficial to improving the focusing effect of the camera module 1000.

[0178] In some embodiments, the two ends of the plate body 114 are connected to the middle regions of the sides of the first excitation plate 111 and the second excitation plate 112, respectively, and the extension 115 is connected to the middle region of the sides of the plate body 114. In this way, the elastic carrier plate 11 is symmetrical along its own axis, and the driving protrusion 13 is disposed in the middle of the plate body 114, so that the driving protrusion 13 is located at the center of the elastic carrier plate 11. The driving body 1 is symmetrical along its own axis, which makes the trajectory of the driving protrusion 13 closer to a circle or ellipse, thereby making the driving protrusion 13 have a more balanced thrust to push the friction plate 20 to move.

[0179] In some embodiments, a piezoelectric ceramic 12 may also be provided on the extension 115.

[0180] In this embodiment, the two piezoelectric ceramics 12 of the driving unit 10 deform due to the inverse piezoelectric effect under the excitation of alternating current, thereby causing the elastic carrier plate 11 to deform and drive the driving protrusion 13 to move. The movement trajectory of the driving protrusion 13 is approximately circular or elliptical, and the movement trajectory of the driving protrusion 13 is perpendicular to the elastic carrier plate 11. Taking the direction shown in Figure 8 as an example, the movement trajectory of the driving protrusion 13 is perpendicular to the XY plane.

[0181] Figure 21 is a schematic diagram of the structure of the elastic carrier plate 11 shown in Figure 13. Referring to Figure 21, the first excitation plate 111, the extension 115, and the plate body 114 are connected to form a U-shaped second edge surface 142, and at least one elastic cantilever 2 is connected to the second edge surface 142; the second excitation plate 112, the extension 115, and the plate body 114 are connected to form a U-shaped third edge surface 143, and at least one elastic cantilever 2 is connected to the third edge surface 143. In this embodiment, there is a void area around the second edge surface 142 and the third edge surface 143. When the elastic cantilever 2 is connected to the second edge surface 142 or the third edge surface 143, a part of the elastic cantilever 2 will be located in the void area, which can reduce the size of the elastic cantilever 2 protruding from the driving body 1, that is, reduce the size of the driving unit 10. This can appropriately reduce the size of the piezoelectric motor 400, thereby reducing the space occupied by the camera module 1000 on the electronic device 10000, which is beneficial to reducing the size of the electronic device 10000.

[0182] The side of the first excitation plate 111 that is close to the second excitation plate 112 is called the first side surface 1111, and the side of the second excitation plate 112 that is close to the first excitation plate 111 is called the second side surface 1121. In this embodiment, the third side surface 1131 of the connecting plate 113 is located on the plate body 114. The side of the plate body 114 that is connected to the first side surface 1111 is the third side surface 1131. The side of the extension 115 that is connected to the third side surface 1131 is the fourth side surface 1151. The first side surface 1111, the third side surface 1131 and the fourth side surface 1151 are connected to form a U-shaped second edge surface 142. The second side surface 1121, the third side surface 1131 and the fourth side surface 1151 are connected to form a U-shaped third edge surface 143.

[0183] Figure 22 is a top view of the drive unit 10 shown in Figure 8. Referring to Figure 22, the drive unit 10 has multiple elastic cantilever arms 2. A portion of the elastic cantilever arms 2 can be connected to the side of the first excitation plate 111 facing the second excitation plate 112, i.e., the elastic cantilever arm 2 is connected to the first side 1111. Another portion of the elastic cantilever arms 2 can be connected to the side of the second excitation plate 112 facing the first excitation plate 111, i.e., the elastic cantilever arm 2 is connected to the second side 1121. Figure 24 is a fourth structural schematic diagram of the drive unit 10 provided in the embodiment of this application. Referring to Figure 24, the elastic cantilever arm 2 can be connected to the side of the extension 115, i.e., the elastic cantilever arm 2 is connected to the fourth side 1151. Figure 25 is a fifth structural schematic diagram of the drive unit 10 provided in the embodiment of this application. Referring to Figure 25, the elastic cantilever arm 2 can also be connected to the side of the plate body 114, i.e., the elastic cantilever arm 2 is connected to the third side 1131.

[0184] Figure 26 is a schematic diagram of the structure of the drive unit 10 provided in the embodiment of this application. Referring to Figure 26, at least one of the elastic cantilever arms 2 is connected to the side of the first excitation plate 111 away from the second excitation plate 112, and at least one of the elastic cantilever arms 2 is connected to the side of the second excitation plate 112 away from the first excitation plate 111. That is to say, the connection position between the elastic cantilever arm 2 and the drive body 1 may not be located in the above-mentioned empty area. At this time, the shape of the elastic cantilever arm 2 is not limited by the size and shape of the above-mentioned empty area, and the shape of the elastic cantilever arm 2 can be designed according to actual needs.

[0185] Referring to Figures 14 to 17, the shaded area in Figure 15 corresponds to the region where the amplitude is zero under the mode of Figure 14, and the shaded area in Figure 17 corresponds to the region where the amplitude is zero under the mode of Figure 16. The piezoelectric ceramic 12 can excite the elastic carrier plate 11 to undergo first-order bending vibration modes under symmetric and antisymmetric constraints. The elastic cantilever 2 is connected to the common node of the two first-order bending vibration modes. In this embodiment, the elastic carrier plate 11 is connected to the fixed part 3 via the elastic cantilever 2, which is equivalent to the elastic cantilever 2 providing support and constraint for the elastic carrier plate 11. It can be understood that the node is the position where the modal vibration value is zero. Referring to Figures 14 to 17, in this embodiment, the first excitation plate 111 and the second excitation plate 112 both have nodal lines in their first-order bending vibration modes under symmetric and antisymmetric constraints, and the nodal lines of these two modes are basically coincident, forming a common node. Therefore, at the common node, the amplitudes of the first excitation plate 111 and the second excitation plate 112 under both symmetric and antisymmetric constraints are zero. Connecting the elastic cantilever 2 to this common node can, on the one hand, reduce the amplitude of the elastic cantilever 2. This reduces the impact on the amplitude of the elastic carrier plate 11, thereby reducing its deformation. On the other hand, it also reduces the pulling force on the elastic cantilever 2 during the inverse piezoelectric effect deformation of the elastic carrier plate 11, thus reducing the impact of the deformation of the elastic carrier plate 11 on the elastic cantilever 2, and further reducing the impact of the deformation of the elastic carrier plate 11 on the fixing part 3. This ensures that the drive unit 10 can be stably fixed inside the piezoelectric motor 400 during the operation of the drive unit 10, ensuring the reliability of the drive unit 10. As a result, the piezoelectric motor 400 has a stable driving force, and the movable lens barrel 300 inside the camera module 1000 moves smoothly under the stable drive of the piezoelectric motor 400. This is beneficial to improving the focusing effect of the camera module 1000.

[0186] In the first-order bending vibration mode, the excitation frequency of the external force is equal to the natural frequency (first order) of the object. The closer the excitation frequency of the external force is to the natural frequency (first order) of the object, the easier it is for the elastic plate 11 to resonate. As a result, the amplitude generated by the elastic plate 11 will be larger, and the range of motion trajectory of the driving protrusion 13 will be larger. Therefore, the energy loss of the excitation will be smaller. Thus, in this embodiment, the first-order bending vibration mode under symmetric and antisymmetric constraints is selected. The actual external force excitation frequency of the driving unit 10 can be set to be close to the natural frequency (first order) of the piezoelectric ceramic 12. This can reduce the energy loss of the excitation and improve the thrust-to-weight ratio of the driving unit 10. For example, the thrust-to-weight ratio of the driving unit 10 is greater than 400.

[0187] In Figures 14 and 16, the fixed part 3 of the drive unit 10 is not subject to external fixed constraints, that is, the fixed part 3 is in a free state. It can be seen that under symmetric constraints and antisymmetric constraints, the fixed part 3 always has a node. Thus, the vibration generated by the excitation of the piezoelectric ceramic 12 has little effect on the fixed part 3. In other words, when the drive unit 10 is excited, the fixed part 3 has almost no amplitude, that is, the fixed part 3 basically does not produce displacement. This can reduce the tension between the fixed part 3 and the components installed with it in the excited state, which is conducive to the stable connection of the fixed part 3 and thus improves the reliability of the drive unit 10.

[0188] In this embodiment, the common node for the formation of the first-order bending vibration mode under symmetric and antisymmetric constraints is located on the side of the first excitation plate 111 near the second excitation plate 112, i.e., on the first side 1111, and on the side of the second excitation plate 112 near the first excitation plate 111, i.e., on the second side 1121. Referring to FIG8, the elastic cantilever 2 can be connected to the side of the first excitation plate 111 near the second excitation plate 112, i.e., connected to the first side 1111, and the elastic cantilever 2 can also be connected to the side of the second excitation plate 112 near the first excitation plate 111, i.e., connected to the second side 1121.

[0189] Figure 23 is a modal diagram of the drive unit 10 shown in Figure 8 under pre-compression. The values ​​corresponding to the scales in Figure 23 represent the degree of deformation of the drive unit 10, in millimeters (mm). Referring to Figure 23, under pre-compression, the elastic cantilever 2 exhibits significant bending deformation, while the first excitation plate 111, the second excitation plate 112, and the connecting plate 113 show less deformation. In other words, by connecting the end of the elastic cantilever 2 to the side of the first excitation plate 111 near the second excitation plate 112 (or to the side of the second excitation plate 112 near the first excitation plate 111), the elastic cantilever 2 can absorb the deformation generated by the pre-compression, thereby ensuring that the drive body 1 remains essentially unchanged under pre-compression. Thus, the shape of the drive body 1 is less affected by the pre-compression. When the magnitude of the pre-compression changes due to assembly precision or other factors, the impact on the shape of the drive body 1 also decreases. This reduces the sensitivity of the drive unit 10 to the pre-compression, thereby improving the stability of the drive unit 10 and reducing the control precision of the pre-compression, thus lowering the operational difficulty of pre-compression. The preload force used in the preload state shown in Figure 23 is 15N. Referring to Figure 23, the deformation of each part of the drive unit 10 in the preload state is magnified by 15 times for easy observation.

[0190] Referring to Figure 22, one fixing part 3 can connect two elastic cantilever arms 2. The number of fixing parts 3 and elastic cantilever arms 2 are not equal. The fixing part 3 can be provided with one fixing hole 31, or it can be provided with two, three or even more fixing holes 31.

[0191] Figure 27 is a schematic diagram of the structure of the drive unit 10 provided in the embodiment of this application. Referring to Figure 27, the number of fixed parts 3 and elastic cantilever 2 are equal, and each fixed part 3 is connected to an elastic cantilever 2. In this embodiment, the drive unit 10 is used inside the piezoelectric motor 400. The fixing part 3 of the drive unit 10 is fixed to the components inside the piezoelectric motor 400 used to install the drive unit 10. That is, the drive unit 10 is installed to the components inside the piezoelectric motor 400 used to install the drive unit 10 through the fixing part 3. In this way, the components inside the piezoelectric motor 400 used to install the drive unit 10 provide support for the elastic cantilever 2 and the drive body 1 of the drive unit 10 through the fixing part 3. The drive protrusion 13 of the drive unit 10 abuts against the friction plate 20 of the piezoelectric motor 400. After the drive unit 10 is excited by the AC signal, the drive protrusion 13 will move. When the drive protrusion 13 moves downward in a circle until it reaches the lowest point, the drive protrusion 13 and the friction plate 20 gradually separate. When the drive protrusion 13 moves upward in a circle until it reaches the highest point, the drive protrusion 13 and the friction plate 20 re-contact and squeeze the friction plate 20, thereby causing the friction plate 20 to move relative to the drive unit 10.

[0192] Figure 19 is a schematic diagram of the free harmonic response mode of the fixing part 3 of the driving unit 10 shown in Figure 8, and Figure 20 is a schematic diagram of the constrained harmonic response mode of the fixing part 3 of the driving unit 10 shown in Figure 8. In Figures 19 and 20, the values ​​corresponding to the scale bars are the amplitudes of the driving unit 10, in micrometers (μm). Referring to Figures 19 and 20, it can be seen from the figures that the fixing part 3 has almost no amplitude under both harmonic response modes. Therefore, the number and shape of the fixing part 3 do not affect the deformation of the elastic carrier plate 11. Thus, the shape and number of fixing holes 31 on the fixing part 3 have a relatively small impact on the amplitude of the driving unit 10. Therefore, the fixing part 3 can be provided with one fixing hole 31, or two, three or even more fixing holes 31. The shape of the fixing hole 31 can also be circular, waist-shaped, square or other shapes.

[0193] Figure 28 is a schematic diagram of the structure of the drive unit 10 provided in the embodiment of this application. Referring to Figure 28, the drive unit 10 also includes a connecting arm 4. The two elastic cantilever arms 2 are connected to the fixing part 3 through the connecting arm 4. That is, the two elastic cantilever arms 2 are not directly connected to the fixing part 3, but are indirectly connected to the fixing part 3 through the connecting arm 4. The ends of the two elastic cantilever arms 2 are respectively connected to the connecting arm 4. In this way, the connecting arm 4 is equivalent to bringing together the ends of the two elastic cantilever arms 2. Then, the connection area reserved on the fixing part 3 can be reduced, so the size of the fixing part 3 can be appropriately reduced, thereby reducing the space occupied by the fixing part 3 in the installation space. This can reduce the size of the piezoelectric motor 400, thereby reducing the space occupied by the piezoelectric motor 400 in the camera module 1000, and further reducing the space occupied by the camera module 1000 on the electronic device 10000. This is beneficial to reduce the size and volume of the electronic device 10000.

[0194] Figure 29 is a structural schematic diagram nine of the drive unit 10 provided in an embodiment of this application, and Figure 30 is a structural schematic diagram ten of the drive unit 10 provided in an embodiment of this application. Referring to Figures 29 and 30, the elastic cantilever 2 is provided with at least two bending portions 21. By increasing the number of bending portions 21 on the elastic cantilever 2, the rigidity of the elastic cantilever 2 can be further reduced, thereby making the elastic cantilever 2 more flexible than the drive body 1. This allows the elastic cantilever 2 to reduce the degree of deformation of the drive body 1 through its own deformation, reducing the impact of preload on the shape of the drive body 1. For example, referring to Figure 29, the elastic cantilever 2 is provided with two bending portions 21, and referring to Figure 30, the elastic cantilever 2 is provided with four bending portions 21. The shape of the elastic cantilever 2 provided in this embodiment is only an example. In other embodiments, the elastic cantilever 2 can also be provided with three, five, or even more bending portions 21. The number of bending portions 21 can be increased or decreased according to actual needs to adjust the shape of the elastic cantilever 2.

[0195] In some embodiments, the number of bends 21 on all elastic cantilever arms 2 is the same. It is understood that the flexibility of an elastic cantilever arm 2 is related to the number of bends 21; the more bends 21 there are, the lower the rigidity of the elastic cantilever arm 2 and the greater its flexibility. Setting the number of bends 21 on all elastic cantilever arms 2 to be the same ensures that the flexibility of each elastic cantilever arm 2 is essentially the same. Therefore, when the drive unit 10 is compressed, the degree of deformation of each elastic cantilever arm 2 is also essentially the same. This reduces the probability of the drive body 1 tilting due to inconsistent deformation of the elastic cantilever arms 2 on both sides, ensuring that the relative position between the drive unit 10 and the friction plate 20 inside the piezoelectric motor 400 meets the requirements, guaranteeing the contact stability between the two, and thus enabling the piezoelectric motor 400 to have a stable driving force. The movable lens barrel 300 inside the camera module 1000 moves smoothly under the stable drive of the piezoelectric motor 400, which is beneficial for improving the focusing effect of the camera module 1000.

[0196] In this embodiment, all the elastic cantilever arms 2 and fixing parts 3 are symmetrically arranged along the central axis of the drive body 1. By symmetrically arranging all the elastic cantilever arms 2 and fixing parts 3 along the central axis of the drive body 1, the forces on both sides of the drive body 1 can be balanced, reducing the probability that the drive body 1 will tilt due to deformation of the elastic cantilever arms 2 on both sides.

[0197] In some embodiments, the preload applied to the drive unit 10 can act on the drive body 1. For example, the piezoelectric ceramic 12 can be preloaded directly, and the preload is transmitted to the drive protrusion 13 through the piezoelectric ceramic 12 and the elastic carrier plate 11. Alternatively, the connecting plate 113 can be preloaded, and the preload is transmitted to the drive protrusion 13 through the connecting plate 113. In other embodiments, the preload applied to the drive unit 10 can act on the fixing part 3, and the preload is transmitted to the drive protrusion 13 through the elastic cantilever 2 and the elastic carrier plate 11.

[0198] In some embodiments, the elastic carrier plate 11, the elastic cantilever 2, and the fixing part 3 are integrally formed; "integral forming" is a common term, usually referring to the process where an object or product is manufactured in a holistic and continuous manner, rather than by processing and assembling multiple parts separately, thus forming a complete and seamless whole. This manufacturing method can reduce assembly steps, improve production efficiency, ensure the structural strength and stability of the product, and reduce the possibility of defects in the connection parts; in this embodiment, the entire plate can be cut or forged to form an integral elastic carrier plate. The plate 11, the elastic cantilever 2, and the fixing part 3 are integrally formed, which can improve the connection strength between the elastic plate 11, the elastic cantilever 2, and the fixing part 3, thereby improving the stability of the drive unit 10. This allows the piezoelectric motor 400 to have a more stable driving force, and the movable lens barrel 300 in the camera module 1000 moves smoothly under the stable drive of the piezoelectric motor 400. This is beneficial to improving the focusing effect of the camera module 1000. In other embodiments, the elastic plate 11, the elastic cantilever 2, and the fixing part 3 can also be formed separately and then connected by welding.

[0199] In this embodiment, the driving protrusion 13 is hemispherical, and the spherical surface of the driving protrusion 13 abuts against the friction plate 20, forming a point contact between the driving protrusion 13 and the friction plate 20. In some embodiments, the driving protrusion 13 may also be semi-cylindrical, and the curved surface of the driving protrusion 13 abuts against the friction plate 20, in which case a line contact is formed between the driving protrusion 13 and the friction plate 20.

[0200] In this embodiment, the polarization direction of the piezoelectric ceramic 12 is parallel to the Z direction. The polarization direction of the piezoelectric ceramic 12 can point towards the elastic carrier plate 11 or away from the elastic carrier plate 11. Of course, the polarization directions of the two piezoelectric ceramics 12 on the driving unit 10 can be the same or different. That is, one piezoelectric ceramic 12 can have its polarization direction pointing towards the elastic carrier plate 11, and the other piezoelectric ceramic 12 can have its polarization direction away from the elastic carrier plate 11. Referring to Figure 8, under the excitation of the AC signal, the movement trajectory of the drive protrusion 13 is perpendicular to the XY plane, that is, the plane on which the movement trajectory of the drive protrusion 13 is located is parallel to the Z direction. Figure 31 is a schematic diagram of the drive unit 10 and the friction plate 20 provided in the embodiment of this application. Referring to Figure 31, in the initial state, under the action of the pre-pressure, the drive protrusion 13 abuts against the friction plate 20. After the drive unit 10 is excited by the AC signal, the drive protrusion 13 will move. When the drive protrusion 13 moves downward in a circle until the lowest point, the drive protrusion 13 and the friction plate 20 gradually separate. When the drive protrusion 13 moves upward in a circle until the highest point, the drive protrusion 13 and the friction plate 20 re-contact and squeeze the friction plate 20, thereby causing the friction plate 20 to move relative to the drive unit 10.

[0201] The driving unit 10 in this embodiment has two piezoelectric ceramics 12. In some embodiments, the two piezoelectric ceramics 12 can be simultaneously connected to AC power. Of course, the AC power corresponding to the two piezoelectric ceramics 12 needs to have a phase difference. For example, one piezoelectric ceramic 12 is connected to an AC signal of U1 = Ucos(ωt), and the other piezoelectric ceramic 12 is connected to an AC signal of U2 = Usin(ωt). Of course, in other embodiments, the two piezoelectric ceramics 12 can also be connected to an AC signal with a square waveform. Compared with a sinusoidal AC signal, a square waveform AC signal has greater energy, which can make the driving bump 13 on the excited driving unit 10 have a greater thrust. For example, the square waveform AC signal can be a pulse width modulation wave (PWM) wave, or a square wave derived from other waveforms.

[0202] Figure 32 is a schematic diagram of the structure of the drive unit 10 provided in the embodiment of this application, and Figure 33 is a bottom view of the drive unit 10 shown in Figure 32. Referring to Figures 32 and 33, the piezoelectric ceramic 12 includes a piezoelectric material layer 121 and a first electrode layer 122 electrically connected to the piezoelectric material layer 121. The first electrode layer 122 is disposed between the piezoelectric material layer 121 and the elastic carrier plate 11. A first flange portion 123 electrically connected to the first electrode layer 122 is also provided on the side of the piezoelectric material layer 121 away from the elastic carrier plate 11. In this embodiment, the first electrode layer 122 is used to connect to the control circuit within the piezoelectric motor 400, thereby transmitting an electrical signal to the piezoelectric material layer 121, causing the piezoelectric material layer 121 to deform due to the inverse piezoelectric effect. The first electrode layer 122 is located between the piezoelectric material layer 121 and the elastic carrier plate 11, making connection to the control circuit difficult. A first flange portion 123, electrically connected to the first electrode layer 122, is provided on the side of the piezoelectric material layer 121 away from the elastic carrier plate 11. The first flange portion 123 is equivalent to an extension of the first electrode layer 122, reducing the height of the first electrode layer. The connection between the first electrode layer 122 and the control circuit is simplified, which also helps to improve the connection stability between the first electrode layer 122 and the control circuit. This allows the piezoelectric ceramic 12 to deform in a preset manner under the excitation of the AC signal from the control circuit. The drive unit 10 generates a stable thrust, which in turn gives the piezoelectric motor 400 a stable driving force. The movable lens barrel 300 in the camera module 1000 moves smoothly under the stable drive of the piezoelectric motor 400, which helps to improve the focusing effect of the camera module 1000 and enables the electronic device 10000 to capture images or videos of better quality.

[0203] Of course, the piezoelectric material layer 121 of the piezoelectric ceramic 12 has two electrodes. A fourth electrode layer 129 is also provided on the side of the piezoelectric material layer 121 away from the elastic carrier plate 11. The fourth electrode layer 129 is also used to connect to the control circuit of the piezoelectric motor 400. That is, the two electrodes on the piezoelectric material layer 121 are connected to the first electrode layer 122 and the fourth electrode layer 129 respectively, and the two electrodes on the piezoelectric material layer 121 are connected to the control circuit through the first electrode layer 122 and the fourth electrode layer 129 respectively. It should be noted that the two electrodes on the piezoelectric material layer 121 are the positive and negative electrodes, respectively. Therefore, one of the first electrode layer 122 and the fourth electrode layer 129 is the positive electrode layer and the other is the negative electrode layer. Therefore, insulation is required between the first flange portion 123 and the fourth electrode layer 129. Insulation can be achieved by arranging the first flange portion 123 and the fourth electrode layer 129 at intervals, or by providing an insulating material (such as insulating adhesive) between the first flange portion 123 and the fourth electrode layer 129.

[0204] Figure 34 is a schematic diagram of the structure of a multilayer piezoelectric ceramic 12 provided in an embodiment of this application. Referring to Figure 34, in some embodiments, the piezoelectric ceramic 12 includes multiple stacked piezoelectric material layers 121 and a second electrode layer 127 disposed between two adjacent piezoelectric material layers 121. The second electrode layer 127 is electrically connected to electrodes of the same polarity on the two adjacent piezoelectric material layers 121, that is, the piezoelectric ceramic 12 is a multilayer piezoelectric ceramic 12. The table below compares the test data of the piezoelectric constant D33 of a single-layer piezoelectric ceramic 12 and a multilayer piezoelectric ceramic 12. The single-layer piezoelectric ceramic 12 and the multilayer piezoelectric ceramic 12 have the same material and total thickness.

[0205] Table 1: Comparison of piezoelectric constant D33 between single-layer and multi-layer piezoelectric ceramics

[0206] Table 1 compares the piezoelectric constants D33 of single-layer and multi-layer piezoelectric ceramics 12. As shown in Table 1, with the same total thickness, the multi-layer piezoelectric ceramic 12 has a higher piezoelectric constant D33 than the single-layer piezoelectric ceramic 12. It can be understood that a higher piezoelectric constant D33 indicates better piezoelectric performance. Therefore, compared to the single-layer piezoelectric ceramic 12, the multi-layer piezoelectric ceramic 12 has better piezoelectric performance. Thus, with the same excitation voltage, the multi-layer piezoelectric ceramic 12 can produce greater deformation. Conversely, with the same degree of deformation, the multi-layer piezoelectric ceramic 12... 2. A lower excitation voltage is required, meaning that a lower voltage can be used to excite the multilayer piezoelectric ceramic 12 to achieve the required driving force for the driving unit 10. Therefore, in space-constrained applications, such as cameras, the multilayer piezoelectric ceramic 12 can be used as the inverse piezoelectric element of the driving unit 10. This eliminates the need for an additional boost circuit to increase the excitation voltage of the piezoelectric ceramic 12, simplifying the circuit structure and reducing its space requirements. This reduces the size of the piezoelectric motor 400, and consequently, the size of the camera module 1000 and the electronic device 10000. For example, the excitation voltage for the piezoelectric ceramic 12 can be 3.3V.

[0207] It is understandable that the degree of deformation of the piezoelectric material layer 121 is affected by the intensity of the alternating electric field; the greater the intensity of the alternating electric field, the greater the degree of deformation of the piezoelectric material layer 121. With the same total thickness, the more piezoelectric material layers 121 contained in the multilayer piezoelectric ceramic 12, the thinner each piezoelectric material layer 121 becomes. The AC signal provided by the control circuit will connect to each piezoelectric material layer 121, respectively exciting each piezoelectric material layer 121 to deform. With a consistent AC voltage, the smaller the distance between the two electrodes on the piezoelectric material layer 121, the greater the deformation. The greater the alternating electric field strength generated within the piezoelectric material layer 121, the thinner the piezoelectric material layer 121 is compared to a single-layer piezoelectric ceramic 12. This results in a greater electric field strength acting between each piezoelectric material layer 121, and a greater deformation per unit thickness of the piezoelectric material layer 121 in the multilayer piezoelectric ceramic 12 compared to a single-layer piezoelectric ceramic 12. Therefore, compared to a single-layer piezoelectric ceramic 12, a multilayer piezoelectric ceramic 12 exhibits greater deformation under the same excitation voltage, thus giving the multilayer piezoelectric ceramic 12 better piezoelectric performance.

[0208] In some embodiments, the piezoelectric ceramic 12 can be selected from lead zirconate titanate ceramic (Pb(Zr1-xTiO3), PZT), which has the following classifications: PZT-2, PZT-4, PZT-5A, PZT-5H, and PZT-8, and the characteristics of each type are as follows:

[0209] PZT-2: Low dielectric constant.

[0210] PZT-4: It has strong depolarization capability under high voltage drive, low dielectric loss, and strong depolarization capability under mechanical force.

[0211] PZT-5A: It exhibits high impedance, high sensitivity, and high stability at elevated temperatures.

[0212] PZT-5H: Its sensitivity and dielectric constant are higher than those of PZT-5A, and its other properties are similar to those of PZT-5A, but its Curie temperature is significantly lower than that of PZT-5A.

[0213] PZT-8: Similar to PZT-4, it has low dielectric loss under high electric field driving.

[0214] Referring to Figure 34, for the multilayer piezoelectric ceramic 12, the second electrode layer 127 between two adjacent piezoelectric material layers 121 is electrically connected to the electrodes with the same polarity on the two adjacent piezoelectric material layers 121. That is, the second electrode layer 127 between two adjacent piezoelectric material layers 121 is shared. This can save the space occupied by the electrode layer in the piezoelectric ceramic 12, reduce the proportion of non-inverse piezoelectric material, and thus improve the piezoelectric performance of the piezoelectric ceramic 12.

[0215] It should be noted that for the multilayer piezoelectric ceramic 12, the polarization directions of two adjacent piezoelectric material layers 121 are opposite. Since the second electrode layer 127 connects to electrodes of the same polarity in two adjacent piezoelectric material layers 121, the circuit traces inside the piezoelectric material layers 121 on both sides of the same second electrode layer 127 need to be arranged in opposite directions. For example, the piezoelectric material layer 121 located above the second electrode layer 127 has its positive electrode facing downwards and its negative electrode facing upwards, and its positive electrode is connected to the second electrode layer 127. Similarly, the piezoelectric material layer 121 located below the second electrode layer 127 has its positive electrode facing upwards and its negative electrode facing downwards, and its positive electrode is also connected to the second electrode layer 127. Since the electrode arrangements of these two piezoelectric material layers 121 are opposite, the electric field directions generated within these two piezoelectric material layers 121 are also opposite after an electrical signal is applied. By setting the polarization directions of two adjacent piezoelectric material layers 121 to opposite directions, the two adjacent piezoelectric material layers 121 can deform in the same direction, reducing the possibility of the two piezoelectric material layers 121 canceling each other out due to opposite deformation directions. This results in a larger overall deformation of the piezoelectric ceramic 12, which allows the drive unit 10 to have a greater thrust to move the friction plate 20. Consequently, the piezoelectric motor 400 can have a greater driving force under the same excitation voltage, or the excitation voltage can be reduced while ensuring equal driving force. This simplifies the circuit structure, reduces the space occupied by the circuit structure, and thus reduces the size of the piezoelectric motor 400, the camera module 1000, and the electronic device 10000.

[0216] Referring again to FIG34, a third electrode layer 128 electrically connected to the piezoelectric material layer 121 is provided between the piezoelectric material layer 121 and the elastic carrier plate 11. A second flange portion 124 and a third flange portion 126 connected to the third electrode layer 128 are also provided on the side of the piezoelectric material layer 121 away from the elastic carrier plate 11. A second electrode layer 127 with the same polarity as the third electrode layer 128 is connected to the third flange portion 126. A second electrode layer 127 with the opposite polarity to the third electrode layer 128 is connected to the third flange portion 126. The second electrode layer 127 is located between two adjacent piezoelectric material layers 121, and the third electrode layer 128 is located between the piezoelectric material layer 121 and the elastic carrier plate 11. Since connecting these two layers to the control circuit is difficult, a second flange 124 and a third flange 126 are provided. These flanges extend the second electrode layer 127 and the third electrode layer 128, reducing the difficulty of connecting them to the control circuit and improving the stability of the connection. This allows the piezoelectric ceramic 12 to deform according to a preset pattern under the excitation of the AC signal from the control circuit, generating a stable thrust from the drive unit 10. This, in turn, provides a stable driving force for the piezoelectric motor 400. The movable lens barrel 300 within the camera module 1000 moves smoothly under the stable drive of the piezoelectric motor 400, improving the focusing effect of the camera module 1000 and enabling the electronic device 1000 to capture higher quality images or videos.

[0217] For ease of understanding, the multilayer piezoelectric ceramic 12 shown in Figure 34 is used as an example for further explanation: The multilayer piezoelectric ceramic 12 shown in Figure 34 has a total of four piezoelectric material layers 121. For ease of understanding, these four piezoelectric material layers 121 are respectively referred to as material layer A121A, material layer B121B, material layer C121C, and material layer D121D. Material layers A121A, B121B, C121C, and D121D are stacked from top to bottom. The second electrode layer 127 between material layer A121A and material layer B121B is referred to as electrode layer A127A, and the second electrode layer 127 between material layer B121B and material layer C121C is referred to as electrode layer B127B. Material layer C121C and material layer D121D are stacked from top to bottom. The second electrode layer 127 between material layers D121D is denoted as electrode layer C127C, and a third electrode layer 128 is disposed below material layer D121D. For example, the third electrode layer 128 can be connected to the negative electrode of material layer D121D. Then, electrode layer C127C is the positive electrode of material layer D121D and material layer C121C. Electrode layer B127B is connected to the negative electrode of material layer C121C and material layer B121B. Electrode layer A127A is connected to the positive electrode of material layer B121B and material layer A121A. Then, the second flange portion 124 is positively polarized and needs to be insulated from the negative electrode of material layer A121A. The third flange portion 126 is negatively polarized and needs to be connected to the negative electrode of material layer A121A.

[0218] Figure 34 is a schematic diagram of the main cross-sectional structure of the piezoelectric motor 400 provided in the embodiment of this application. Referring to Figure 35, the piezoelectric motor 400 provided in the embodiment of this application includes a friction plate 20 and a drive unit 10 as described in any of the above embodiments. The drive protrusion 13 of the drive unit 10 abuts against the friction plate 20. Since the deformation of the drive body 1 in the initial state of the drive unit 10 is small, the drive unit 10 can deform in a preset manner under the action of alternating current, and the drive protrusion 13 of the drive unit 10 can move along a preset trajectory, thereby stably pushing the friction plate 20 to move relative to the drive unit 10. Therefore, the piezoelectric motor 400 in the embodiment of this application has high driving accuracy. Since the drive unit 10 has low sensitivity to pre-pressure, its shape in the initial state is less affected by pre-pressure. Therefore, during the assembly process of the piezoelectric motor 400 in the embodiment of this application, the control accuracy of pre-pressure can be appropriately relaxed, which can reduce the assembly difficulty of the piezoelectric motor 400, which is conducive to reducing its production cost and improving production efficiency.

[0219] In some embodiments, the piezoelectric motor 400 is a linear motor, meaning the friction plate 20 moves linearly relative to the drive unit 10. This application provides a feasible method for mounting the friction plate 20 and the drive unit 10. Figure 35 is a schematic front cross-sectional view of the piezoelectric motor 400 provided in this application embodiment. Referring to Figures 35 and 36, the piezoelectric motor 400 also includes a housing 30, with the drive unit 10 disposed within the housing 30. The friction plate 20 is disposed at the opening of the housing 30, and the friction plate 20 is slidably connected to the housing 30. Referring to Figure 36, the two sides of the friction plate 20... A sliding groove is provided on the side, the length of which extends along the moving direction of the friction plate 20. The edge of the opening of the housing 30 is inserted into the sliding groove. The cooperation between the edge of the opening of the housing 30 and the sliding groove of the friction plate 20 restricts the moving direction of the friction plate 20, so that the friction plate 20 can only reciprocate in a straight line. In other embodiments, the friction plate 20 and the drive unit 10 can be installed in other ways, such as using a slide rail to guide the movement of the friction plate 20. The structure provided in this example does not limit the installation method of the piezoelectric motor 400 on the friction plate 20 and the drive unit 10.

[0220] In one embodiment, referring to FIG35, the piezoelectric motor 400 is further provided with a pre-compression member 40, which abuts against the fixing part 3. Abutting the pre-compression member 40 against the fixing part 3 applies pre-pressure to the fixing part 3. The pre-pressure can be transmitted to the drive protrusion 13 through the elastic cantilever 2 and the elastic carrier plate 11. The drive body 1 is not directly compressed by the pre-pressure, thus reducing the impact of the pre-pressure on the shape of the drive body 1. Exemplarily, the fixing part 3 and the pre-compression member 40 can be welded together or glued together. Alternatively, a fixing hole 31 can be provided on the fixing part 3, and a threaded hole can be provided on the pre-compression member 40. A fixing screw can be screwed through the fixing hole 31 into the threaded hole to achieve connection. In this embodiment, the side of the drive body 1 away from the friction plate 20 may not have any support structure, which makes the drive body 1 approximately suspended, reducing the influence of external forces on the shape of the drive body 1, thereby improving the driving stability of the drive unit 10 and thus improving the reliability of the piezoelectric motor 400. Since the side of the drive body 1 away from the friction plate 20 may not have any support structure, the number of components inside the piezoelectric motor 400 can be reduced, which is conducive to designing a smaller piezoelectric motor 400, thereby reducing the space occupied by the piezoelectric motor 400. This can reduce the volume of the camera module 1000 and the space occupied by the camera module 10000 in the electronic device 10000, which is conducive to reducing the size and volume of the electronic device 10000.

[0221] In this embodiment, the preload 40 can also serve to fix the drive unit 10.

[0222] Figure 37 is a second schematic diagram of the main cross-sectional structure of the piezoelectric motor 400 provided in an embodiment of this application. Referring to Figure 37, in some embodiments, the pre-compression member 40 of the piezoelectric motor 400 is pressed against the drive body 1 of the drive unit 10. Pressing the pre-compression member 40 against the drive body 1 of the drive unit 10 means applying pre-pressure to the drive body 1. For example, the piezoelectric ceramic 12 can be pre-compressed directly, and the pre-pressure is transmitted to the drive protrusion 13 through the piezoelectric ceramic 12 and the elastic carrier plate 11, or the pre-pressure can be applied to the connecting plate 113. In this embodiment, the pre-compression member 40 is located between the drive unit 10 and the inner wall of the housing 30. Thus, the pre-pressure on the drive unit 10 can be adjusted by increasing the thickness of the pre-compression member 40. It should be noted that since the pre-compression member 40 is in direct contact with the drive body 1, and the drive body 1 will deform when excited by the AC signal, the pre-compression member 40 can have a certain degree of flexible buffering performance to adapt to the deformation of the drive body 1. For example, the second pre-compression member 40 can be a buffer cotton, rubber pad, etc.

[0223] The piezoelectric motor 400 is also equipped with a control circuit, which is electrically connected to the two piezoelectric ceramics 12 of the drive unit 10. The control circuit provides an electrical signal to one of the piezoelectric ceramics 12. That is, at any given moment, the control circuit of the piezoelectric motor 400 only provides an electrical signal to one of the piezoelectric ceramics 12, and only one of the two piezoelectric ceramics 12 on the drive unit 10 is excited at any given moment, i.e., unilateral excitation.

[0224] Figure 38 is a schematic diagram of the single-sided excitation mode of the drive unit 10 shown in Figure 8. Referring to Figure 38, the following explanation is given using the example of the control circuit of the piezoelectric motor 400 energizing only the piezoelectric ceramic 12 on the first excitation plate 111 (i.e., the piezoelectric ceramic 12 located at the top in Figure 38): In one instant, the control circuit applies an electric field in the first direction to the piezoelectric ceramic 12. The piezoelectric ceramic 12 is excited and deforms, causing the corresponding first excitation plate 111 to produce a corresponding first deformation. The energy generated by the excitation of the piezoelectric ceramic 12 is transferred to the second excitation plate 112 through the connecting plate 113, causing the second excitation plate 112 to produce a second deformation in the same direction as the first deformation. In the next instant, the control circuit applies an electric field in the second direction to the piezoelectric ceramic 12 connected to the first excitation plate 111. The second direction is opposite to the first direction, causing the first excitation plate 111 to produce a third deformation opposite to the first deformation. At this moment, since the deformation force of the third deformation produced by the first excitation plate 111 has not yet been transmitted to the second excitation plate 112, the second excitation plate 112 still maintains the posture of the second deformation under the action of inertia. That is to say, at this moment, the deformation directions of the first excitation plate 111 and the second excitation plate 112 of the driving unit 10 are opposite, so that the driving unit 10 has a mode approximately as shown in Figures 19 and 20. Referring to Figure 38, if only one of the piezoelectric ceramics 12 on the driving unit is energized and excited, the driving bump 13 can also produce displacement. Thus, under the excitation of the alternating current signal, the driving bump 13 can produce a first trajectory motion approximately circular or elliptical.

[0225] Correspondingly, when the piezoelectric motor 400 only energizes the piezoelectric ceramic 12 on the second excitation plate 112, the deformation sequence between the first excitation plate 111 and the second excitation plate 112 is the opposite of the deformation sequence in the above-mentioned case where only the piezoelectric ceramic 12 on the first excitation plate 111 is energized. This allows the driving protrusion 13 to generate a second trajectory movement opposite to the first trajectory movement direction, thereby enabling the friction plate 20 to reciprocate along a preset direction and realize the position adjustment between the friction plate 20 and the driving unit 10.

[0226] Referring to Figures 19 and 20, when the piezoelectric ceramic 12 is excited, the energy transmitted from the driving body 1 to the elastic cantilever 2 is minimal (or non-existent). In other words, the driving unit 10 provided in this embodiment has low energy loss, and most (or all) of the energy in the driving unit 10 can be used to induce the driving protrusion 13 to generate a trajectory motion, thereby forming a thrust. Therefore, even with unilateral excitation (i.e., providing an electrical signal to only one of the piezoelectric ceramics 12 on the driving unit 10 at the same time), the driving protrusion 13 can still be induced to generate a corresponding trajectory motion to form a thrust.

[0227] Since unilateral excitation provides an electrical signal to only one of the piezoelectric ceramics 12 on the drive unit 10 at any given time, and the circuit control does not involve the phase difference control of the AC signal between the two piezoelectric ceramics 12, unilateral excitation, i.e., providing an electrical signal to only one of the piezoelectric ceramics 12 on the drive unit 10 at any given time, can reduce the difficulty of circuit control. On the other hand, since unilateral excitation does not involve the phase difference of the AC signal between the two piezoelectric ceramics 12 in circuit control, the sensitivity of unilateral excitation to the assembly process of the drive unit 10 will be reduced, which can reduce the assembly process difficulty of the drive unit 10. This also reduces the assembly process difficulty of the piezoelectric motor 400, and is also conducive to improving the reliability of the piezoelectric motor 400, thereby improving the reliability of the camera module 1000 and the electronic device 10000.

[0228] Compared to dual-sided excitation (i.e., simultaneously exciting the two piezoelectric ceramics 12 on the drive unit 10), the drive unit 10 using single-sided excitation is less sensitive to preload. For example, if the preload is increased by 10%, the thrust of the drive unit 10 will decrease by 50% under dual-sided excitation, while the thrust of the drive unit 10 will increase under single-sided excitation. Compared to dual-sided excitation, single-sided excitation also has a larger frequency window. For example, under dual-sided excitation, the frequency window of the drive unit 10 is 62-63kHz, while under single-sided excitation, the frequency window of the drive unit 10 is 60-65kHz.

[0229] In some embodiments, multiple drive units 10 may be provided within the piezoelectric motor 400, and the multiple drive units 10 share the drive friction plate 20 to move.

[0230] The camera module 1000 provided in this application embodiment includes the piezoelectric motor 400 in any of the above embodiments. Since the piezoelectric motor 400 has high driving accuracy, the camera module 1000 using this piezoelectric motor 400 can stably drive the movable lens barrel 300 to move, accurately realize the adjustment of the focal length, and have a high focusing effect.

[0231] It should be noted that the piezoelectric motor 400 in this embodiment is not limited to adjusting the focus within the camera module 1000. For example, the piezoelectric motor 400 can also be connected to the photosensitive element (such as the image sensor 800) within the camera module 1000, so that the camera module 1000 has the function of image stabilization.

[0232] Of course, multiple piezoelectric motors 400 can be installed inside the camera module 1000, and the movable lens barrel 300 can be moved synchronously by the multiple piezoelectric motors 400.

[0233] Of course, the piezoelectric motor 400 in this embodiment is not limited to use in the camera module 1000. For example, it can also be used in a phase shifter. For example, for a phase shifter of a wireless module, the piezoelectric motor 400 can be connected to a key component (such as an antenna) in the phase shifter, thereby driving such a key component to move and realize the adjustment of the wireless signal transmission direction. The phase shifter can be an analog phase shifter or a digital phase shifter. Analog phase shifters include physical phase shifters and dielectric phase shifters. Physical phase shifters can change the physical length through which electromagnetic waves travel, and they have low loss and low cost. Dielectric phase shifters can change the wavelength of electromagnetic waves in the propagation medium, which is beneficial to reducing the size of the wireless module and improving the layout of the antenna inside the wireless module. Digital phase shifters have the characteristics of high accuracy, high cost, low power and real-time adjustment. Digital phase shifters include switch-type phase shifters, reflective phase shifters, loaded phase shifters, hybrid phase shifters, micro-electro-mechanical system (MEMS) phase shifters, etc.

[0234] For example, the piezoelectric motor 400 can also be used as a linear motor. For instance, the drive unit 10 or friction plate 20 of the piezoelectric motor 400 can be connected to a telescopic rod, allowing the piezoelectric motor 400 to drive the telescopic rod in telescopic motion. Alternatively, the drive unit 10 or friction plate 20 of the piezoelectric motor 400 can be connected to a load, allowing the piezoelectric motor 400 to move the load. It should be noted that the above examples are merely illustrations of the applications of the piezoelectric motor 400. The piezoelectric motor 400 can also be applied to other fields, and this embodiment does not impose any limitations on its application.

[0235] The electronic device 10000 provided in this application embodiment includes the above-mentioned camera module 1000. Since the camera module 1000 has a high focusing effect, the photos or videos taken by the electronic device 10000 using this camera module 1000 are of good quality.

[0236] In some embodiments, the electronic device 10000 has a power supply module (not shown in the figure), which is electrically connected to the piezoelectric motor 400. The power supply module provides an AC signal to the piezoelectric motor 400, and the waveform of the AC signal is a square waveform or a sine wave. Compared with a sine wave AC signal, a square waveform AC signal has greater energy, which allows the driven bump 13 on the excited drive unit 10 to have greater thrust. Figure 39 is a schematic diagram of a square waveform provided in an embodiment of this application. The square waveform can be the waveform shown in Figure 39. For example, the square waveform AC signal can be a pulse width modulation wave (PWM) wave, or a square wave derived from other waveforms.

[0237] In this embodiment, the power supply module of the electronic device 10000 is connected to the piezoelectric ceramic 12 through the control circuit in the piezoelectric motor 400. The AC signal provided by the power supply module generates an alternating electric field in the piezoelectric ceramic 12. The piezoelectric ceramic 12 deforms due to the inverse piezoelectric effect. This process is the conversion of electrical energy into kinetic energy. The deformation generated by the piezoelectric ceramic 12 is transmitted to the driving protrusion 13 through the elastic carrier plate 11, causing the driving protrusion 13 to move in a trajectory. This allows the driving protrusion 13 to generate mutual friction with the friction plate 20, driving the friction plate 20 to move relative to the driving unit 10. This process converts the microscopic deformation of the driving unit 10 into the macroscopic movement of the friction plate 20, that is, converting microscopic vibration energy into macroscopic kinetic energy. The relative movement of the friction plate 20 and the driving unit 10 can cause the piezoelectric motor 400 to generate thrust, which causes the movable lens barrel 300 in the camera module 1000 to move, realizing the focusing of the camera module 1000, thereby enabling the electronic device 10000 to capture clear images or videos.

[0238] Finally, it should be noted that the above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A driving unit, characterized in that, include: The driving body (1) includes an elastic carrier plate (11) and driving protrusions (13) and piezoelectric ceramics (12) disposed on the elastic carrier plate (11); An elastic cantilever (2) having a bending portion (21); The fixing part (3) and the driving body (1) are connected by the elastic cantilever (2), and the fixing part (3) is used to support the elastic cantilever (2) and the driving body (1).

2. The driving unit according to claim 1, characterized in that, The elastic carrier plate (11) includes a first excitation plate (111) and a second excitation plate (112) spaced apart, and a connecting plate (113) connecting the first excitation plate (111) and the second excitation plate (112). The driving protrusion (13) is disposed on the connecting plate (113). Both the first excitation plate (111) and the second excitation plate (112) are provided with the piezoelectric ceramic (12).

3. The driving unit according to claim 2, characterized in that, The first excitation plate (111), the second excitation plate (112) and the connecting plate (113) are connected to form a U-shaped first edge surface (141), and at least one of the elastic cantilever (2) is connected to the first edge surface (141).

4. The driving unit according to claim 2, characterized in that, The connecting plate (113) includes a plate body (114) connecting the first excitation plate (111) and the second excitation plate (112). Both sides of the plate body (114) extend in a direction away from the center of the plate body (114) to form extension portions (115). The extension portions (115) are located between the first excitation plate (111) and the second excitation plate (112). The driving protrusion (13) is disposed on the plate body (114).

5. The driving unit according to claim 4, characterized in that, The first excitation plate (111), the extension (115), and the plate body (114) are connected to form a U-shaped second edge surface (142), and at least one of the elastic cantilever (2) is connected to the second edge surface (142); and / or, The second excitation plate (112), the extension (115) and the plate body (114) are connected to form a U-shaped third edge surface (143), and at least one of the elastic cantilever (2) is connected to the third edge surface (143).

6. The driving unit according to claim 3 or 5, characterized in that, The piezoelectric ceramic (12) can excite the elastic carrier plate (11) to undergo first-order bending vibration modes under symmetric and antisymmetric constraints, and the elastic cantilever (2) is connected to the common node of the two first-order bending vibration modes.

7. The driving unit according to claim 2, characterized in that, At least one of the elastic cantilever arms (2) is connected to the side of the first excitation plate (111) opposite to the second excitation plate (112); and / or, At least one of the elastic cantilever (2) is connected to the side of the second excitation plate (112) opposite to the first excitation plate (111).

8. The driving unit according to any one of claims 1-7, characterized in that, The drive unit (10) also includes a connecting arm (4), through which the two elastic cantilever arms (2) are connected to the fixing part (3).

9. The driving unit according to any one of claims 1-8, characterized in that, The piezoelectric ceramic (12) includes a piezoelectric material layer (121) and a first electrode layer (122) electrically connected to the piezoelectric material layer (121). The first electrode layer (122) is disposed between the piezoelectric material layer (121) and the elastic carrier plate (11). A first flange portion (123) electrically connected to the first electrode layer (122) is also provided on the side of the piezoelectric material layer (121) away from the elastic carrier plate (11).

10. The driving unit according to any one of claims 1-9, characterized in that, The piezoelectric ceramic (12) includes multiple stacked piezoelectric material layers (121) and a second electrode layer (127) disposed between two adjacent piezoelectric material layers (121), wherein the second electrode layer (127) is electrically connected to electrodes of the same polarity on the two adjacent piezoelectric material layers (121).

11. The driving unit according to claim 10, characterized in that, A third electrode layer (128) electrically connected to the piezoelectric material layer (121) is provided between the piezoelectric material layer (121) and the elastic carrier plate (11). A second flange (124) and a third flange (126) connected to the third electrode layer (128) are also provided on the side of the piezoelectric material layer (121) away from the elastic carrier plate (11). A second electrode layer (127) with the same polarity as the third electrode layer (128) is connected to the third flange (126). A second electrode layer (127) with the opposite polarity to the third electrode layer (128) is connected to the third flange (126).

12. The drive unit according to any one of claims 1-11, characterized in that, At least two bending portions (21) are provided on the elastic cantilever (2).

13. The drive unit according to any one of claims 1-12, characterized in that, The elastic carrier plate (11), the elastic cantilever (2), and the fixing part (3) are integrally formed.

14. A piezoelectric motor, comprising a friction plate (20), characterized in that, It also includes a drive unit (10) as described in any one of claims 1-13, wherein the drive protrusion (13) of the drive unit (10) abuts against the friction plate (20).

15. The piezoelectric motor according to claim 14, characterized in that, The piezoelectric motor (400) is also provided with a preload member (40), which abuts against the fixing part (3) of the drive unit (10), and / or the preload member (40) abuts against the drive body (1) of the drive unit (10).

16. The piezoelectric motor according to claim 14, characterized in that, The piezoelectric motor (400) is also provided with a control circuit, which is connected to all the piezoelectric ceramics (12) on the drive unit (10) respectively, and the control circuit provides an electrical signal to one of the piezoelectric ceramics (12).

17. A camera module, characterized in that, Including the piezoelectric motor (400) as described in any one of claims 14-16.

18. An electronic device, characterized in that, Includes the camera module (1000) as described in claim 17.

19. The electronic device according to claim 18, characterized in that, The electronic device (10000) has a power supply module, which is electrically connected to the piezoelectric motor (400). The power supply module provides an AC signal to the piezoelectric motor (400), and the waveform of the AC signal is a square waveform or a sine waveform.

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