CN118042258A - Camera module, driving mode and electronic equipment - Google Patents

Abstract

The invention provides a camera module, a driving mode and electronic equipment, wherein the camera module comprises: the lens barrel and the piezoelectric actuating assembly is arranged on one side of the lens barrel, and the piezoelectric actuating assembly vibrates to rub and drive the lens barrel to move along the optical axis of the lens. Based on the principle of an in-plane composite mode, the piezoelectric actuation assembly does not need a mechanical conduction structure of a traditional motor such as a screw rod, a gear, a speed reducer and the like while meeting the driving force and the stroke, and the formed camera module is compact in structure and low in requirements on processing and assembly; the piezoelectric actuating assembly receives the excitation signal to vibrate and drives the elastic vibrating piece to resonate, has larger vibration energy, higher energy density and higher driving efficiency, and can provide larger output force than an inertial motor under the same volume.

Description

Camera module, driving mode and electronic equipment

Technical Field

The invention relates to the field of camera modules, in particular to a camera module, a driving mode and electronic equipment.

Background

With the rapid development of technology, the operation performance of the smart phone can meet the use requirements of most users, and with the transition of the user requirements, the requirement on the photographing performance of the smart phone is higher and higher, and the operation performance of the smart phone becomes one of important performance indexes for measuring the smart phone.

The light and thin design is the main stream direction of the current smart phone development, and the camera module is thinned along with the thickness reduction of the smart phone. Unlike digital cameras, smartphones cannot mount optical zoom lenses with large focusing distances, for which conventional optical zoom camera modules are no longer suitable. Moreover, with the increasing demand for focal length zoom, conventional voice coil motor strokes cannot match the design demands of long strokes, large driving forces, and closed loops.

The piezoelectric motor of the existing mobile phone lens is based on inertial drive, has high requirements on friction force control of surfaces of a rotor and a stator, is extremely easy to be interfered by processing errors, assembly errors and external environments, is difficult to ensure consistency of products, and is not beneficial to large-scale industrialization; moreover, piezoelectric motors based on inertial drive rely heavily on accurate excitation signals, which puts high design demands on the drive control system. In addition, the vibration efficiency is low, the output force is small, and the product requirement of larger driving force cannot be matched.

Therefore, the miniaturization of the focusing/zooming device is realized, the driving efficiency of the camera module is improved, and the camera module has stronger practical significance.

Disclosure of Invention

The invention aims to provide a camera module, a driving mode and electronic equipment, wherein the camera module is driven by a piezoelectric actuation assembly, has a simple structure, effectively reduces the volume of the camera module and improves the driving efficiency of focusing/zooming of a lens.

Based on the above, the present invention provides a camera module, which is characterized by comprising: a lens barrel having at least one lens therein; a piezoelectric actuation assembly provided at one side of the lens barrel; the piezoelectric actuating component vibrates to rub and drive the lens barrel to move along the optical axis of the lens.

Preferably, the piezoelectric actuating assembly includes a piezoelectric member and an elastic vibration member connected to each other, and the piezoelectric member vibrates and drives the elastic vibration member to resonate and rub the lens barrel.

Preferably, the resonance includes a first-order longitudinal vibration and a second-order bending vibration which are generated simultaneously so as to make each point on the surface of the elastic vibration member vibrate along an elliptical track.

Preferably, the piezoelectric element is a single-piece partition driving structure or a multi-piece common driving structure.

Preferably, along the length direction of the elastic vibration piece, one end of the piezoelectric piece is connected with the elastic vibration piece, and the other end of the piezoelectric piece is provided with two piezoelectric partitions or two piezoelectric fragments with the same polarization direction.

Preferably, the polarization direction is parallel to the length direction.

Preferably, the two piezoelectric partitions or the two piezoelectric patches are symmetrically distributed.

Preferably, the upper surface and the lower surface of the piezoelectric element are respectively provided with an electrode; wherein the electrode on the upper surface or the lower surface is connected with the elastic vibrating piece and grounded; the electrodes on the lower surface or the upper surface are connected with excitation signals to respectively correspond to the two piezoelectric partitions or the two piezoelectric patches.

Preferably, the method further comprises: a housing provided with a receiving groove corresponding to the lens barrel and a mounting groove corresponding to the piezoelectric actuation assembly; wherein the piezoelectric element is fixedly arranged in the mounting groove through a soft bonding material; the elastic vibrating piece is magnetically attracted and/or abutted against the lens barrel.

Preferably, the material of the elastic vibration member includes a metal material and/or a magnetic material, and further includes: and the magnetic component is fixedly arranged on the side wall of the lens barrel so as to magnetically attract the elastic vibrating piece.

Preferably, the method further comprises: and the elastic support piece is fixedly arranged between the elastic vibration piece and the mounting groove so as to enable the elastic vibration piece and the lens barrel to abut against each other.

Preferably, the elastic vibration member drives the lens barrel by point friction, line friction or surface friction.

Preferably, a ceramic hemisphere or a ceramic boss in friction contact with the lens barrel is fixedly arranged on the side wall of the elastic vibrating piece.

Preferably, the elastic vibrating member has a symmetrical cross section.

Preferably, the material of the piezoelectric element comprises a rigid piezoelectric material.

Preferably, a guide structure is provided in the lens barrel to linearly reciprocate along the optical axis and to realize focusing of the lens.

Preferably, the method further comprises: the position detecting element feeds back position information of the lens barrel.

Preferably, the position detecting element includes one or a combination of two of a hall sensor and a capacitive grid sensor.

Preferably, the inner wall of the lens barrel is coated with an anti-reflection material or a light shielding material.

Another aspect of the present invention provides a method for driving a camera module, including: providing an excitation signal to the piezoelectric actuation assembly; the piezoelectric actuating component receives the excitation signal to vibrate so as to rub and drive the lens barrel to move along the optical axis of the lens arranged in the lens barrel.

Preferably, the excitation signal is provided to excite the piezoelectric actuation assembly to vibrate, whereas the piezoelectric actuation assembly stiction blocks the lens barrel to self-lock.

Preferably, the piezoelectric actuating assembly comprises a piezoelectric element and an elastic vibrating element which are connected, and the excitation signal comprises a two-phase sinusoidal signal; the piezoelectric element receives the two-phase sinusoidal signals to vibrate and drive the elastic vibration element to generate first-order longitudinal vibration and second-order bending vibration simultaneously.

Preferably, the two-phase sinusoidal signals have the same frequency and a phase difference of 90 °.

Preferably, the ratio of the characteristic frequency difference between the first-order longitudinal vibration and the second-order bending vibration to the frequency of the two-phase sinusoidal signal is not more than 0.03.

The invention also provides electronic equipment comprising the camera module.

The piezoelectric actuating assembly receives excitation signals to vibrate so as to rub and drive the lens barrel to move along the optical axis of the lens, so that the driving force and the stroke are met, meanwhile, the mechanical conduction structures of traditional motors such as screw rods, gears and speed reducers are not needed, and the formed camera module has the characteristic of compact structure.

Furthermore, based on the principle of an in-plane composite mode, the camera module has lower requirements on processing and assembly; and the piezoelectric member vibrates and drives the elastic vibrating member to resonate, so that the piezoelectric member has larger vibration energy, higher energy density and higher driving efficiency. At the same volume, a greater output force can be provided than with an inertial motor.

Further, the elastic vibration piece can drive the lens barrel through point friction, line friction or surface friction, the excitation signal is provided for exciting the piezoelectric piece to vibrate and transmitting the elastic vibration piece to resonate and rub the lens barrel, otherwise, the elastic vibration piece is blocked by static friction to self-lock the lens barrel, the anti-shake function is achieved, and the stable working state of the camera module is guaranteed.

Further, by controlling the excitation signal, accurate driving of the camera module is achieved, and response speed is high.

Drawings

Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments which follows, which is read in connection with the accompanying drawings.

FIG. 1 is an exploded perspective view of a camera module according to an embodiment of the present invention;

FIG. 2 is a diagram showing an assembly relationship between a lens barrel and a piezoelectric actuator assembly of a camera module according to an embodiment of the present invention;

FIG. 3 is a diagram showing an assembly relationship between a lens barrel and a piezoelectric actuator assembly of another camera module according to an embodiment of the present invention;

FIG. 4 is a diagram showing the assembly relationship between the piezoelectric actuator assembly and the housing of the camera module according to the embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a piezoelectric actuator assembly of a camera module according to an embodiment of the present invention;

Fig. 6 is a schematic phase diagram of the piezoelectric actuation assembly shown in fig. 5 with an excitation signal applied.

In the drawings, the same or similar reference numerals denote the same or similar devices (modules) or steps throughout the different drawings.

Detailed Description

In order to make the contents of the present invention more clear and understandable, the contents of the present invention will be further described with reference to the accompanying drawings. Of course, the invention is not limited to this particular embodiment, and common alternatives known to those skilled in the art are also encompassed within the scope of the invention.

In the following detailed description of the embodiments of the present invention, the structures of the present invention are not drawn to a general scale, and the structures in the drawings are partially enlarged, deformed, and simplified, so that the present invention should not be construed as being limited thereto.

FIG. 1 is an exploded perspective view of a camera module according to an embodiment of the present invention; FIG. 2 is a diagram showing an assembly relationship between a lens barrel and a piezoelectric actuator assembly of a camera module according to an embodiment of the present invention; fig. 3 is an assembly relationship diagram of a lens barrel and a piezoelectric actuator assembly of another camera module according to an embodiment of the present invention.

As shown in fig. 1, the camera module includes: a housing 10 accommodating the lens barrel 20 in an inner space thereof; a lens barrel 20 having one or more lenses (not shown) disposed therein; a piezoelectric actuation assembly 30 formed in the housing 10 and provided at one side of the lens barrel 20, and configured to generate a driving force to drive the lens barrel 20 in the internal space.

The piezoelectric actuating assembly 30 receives the excitation signal to vibrate so as to rub and drive the lens barrel 20 to move along the optical axis of the lens, so that the driving force and the stroke are satisfied, meanwhile, the mechanical conduction structure of a traditional motor such as a screw rod, a gear and a speed reducer is not needed, and the camera module has the characteristics of compact structure and large driving force.

The camera module further comprises an image sensor unit (not shown). In addition, the camera module may further include a shield (not shown). In addition to the above components, the camera module may further include a position detecting element that detects a relative position of the lens barrel 20 with respect to the image sensor unit, for example, one or a combination of two of a hall sensor and a grid sensor to feed back position information of the lens barrel 20.

The lens barrel 20 linearly reciprocates along the optical axis and focuses the lens, and a guide structure (not shown) may be provided therein to increase the stability of the optical axis.

The lens barrel 20 has a hollow cylindrical groove to accommodate one or more lenses, which are disposed in the lens barrel 20 along an optical axis. Lenses having different forms may be placed in the lens barrel 20, and the specific lens may be determined according to the type of camera module. Light incident through the lens may be collected to an image sensor (not shown), whereby an image may be photographed. The shape and structure of the lens barrel 20 shown in fig. 1 to 3 are only one example. I.e., the shape and kind of the exemplary lens barrel 20 are not particularly limited and may be modified by those skilled in the art.

The inner surface of the lens barrel 20 may be coated with an anti-reflection material or a light shielding material to reduce unwanted light reflected to the inner surface of the lens barrel 20 to be incident on the image sensor, thereby improving the imaging quality of the camera module.

The housing 10 is made of a material having good impact resistance, which may be metal, plastic or a composite material. Other materials are also possible if necessary.

The housing 10 may house the lens barrel 20 and the piezoelectric actuation assembly 30 therein. Specifically, the housing 10 is provided with a receiving groove 11 that receives the lens barrel 20 and a mounting groove 12 that fixes the piezoelectric actuation assembly 30.

The case 10 encloses the lens barrel 20 to protect its lens assembly from external impact and prevent foreign substances from entering, so that the driving performance of the camera module can be stably maintained and improved. The piezoelectric actuation assembly 30 effectively drives the lens barrel 20 to move in the optical axis direction in the inner space of the housing 10.

The receiving groove 11 may be generally formed at the middle of the case 10. More specifically, the accommodation groove 11 may be penetrated in the vertical direction with respect to one surface of the image sensor unit 14.

The receiving groove 11 may have a cross section larger than the lens barrel 20. Specifically, the accommodation groove 11 may have a larger cross section than the lens barrel 20 so that the lens barrel 20 accommodated in the accommodation groove 11 can move in the optical axis direction.

The mounting groove 12 may be formed near the edge of the receiving groove 11. When the mounting groove 12 is formed at the edge of the housing 10 as described above, the space utilization of the housing 10 can be increased, thereby facilitating miniaturization of the camera module.

As shown in fig. 1, the piezoelectric actuator assembly 30 includes an elastic vibration member 31 and a piezoelectric member 32 connected to each other, and the piezoelectric member 32 vibrates and drives the elastic vibration member 31 to resonate and rub the lens barrel 20.

The piezoelectric element 32 may be fixed in the mounting groove 12 by a soft adhesive material (not shown).

The elastic vibration member 31 has a symmetrical cross section and may be generally rectangular (the cross section in the optical axis direction is rectangular, so this is also referred to herein as a rectangular elastic body), and specifically, the elastic vibration member 31 has a rectangular shape having a length L and a width W in cross section. For reference, although the case where the elastic vibration member 31 has only a rectangular cross section has been described in the present embodiment, the elastic vibration member 31 is not limited to having a rectangular shape. For example, the elastic vibration member 31 may have another shape as long as the elastic vibration member 31 can transmit the vibration of the piezoelectric member 32 to the lens barrel 20. For example, the elastic vibration member 31 may be manufactured to have a cylindrical shape and a diamond shape in cross section.

The elastic vibration member 31 may drive the lens barrel 20 by point friction, line friction or surface friction, and provide the excitation signal to excite the piezoelectric member 32 to vibrate, whereas the piezoelectric actuation assembly static friction blocks the lens barrel to self-lock, so as to have an anti-shake function and ensure a stable working state of the camera module.

The side wall of the elastic vibrating member 31 may be fixedly provided with one or more ceramic hemispheres 33 or ceramic bosses (not shown), and the ceramic hemispheres 33 or the ceramic bosses are disposed between the elastic vibrating member 31 and the lens barrel 20, so as to reduce the contact area therebetween to increase the friction force and further improve the driving force.

The material of the elastic vibration member 31 includes a metal material and/or a magnetic material. For example, if the piezoelectric actuator assembly 30 is made of a magnetic material, the piezoelectric actuator assembly may be magnetically attracted to the outside of the lens barrel 20 by the attractive force of the magnetic material.

As shown in fig. 2, the elastic vibrator 31 may be made of a metal material, and the elastic vibrator 31 may be magnetically attracted to the outside of the lens barrel 20 by the magnetic member 24.

The magnetic member 24 may be fixed to a side portion of the lens barrel 20 to increase the adhesion between the lens barrel 20 and the piezoelectric actuation assembly 30.

The contact between the elastic vibration member 31 and the lens barrel 20 is not limited to magnetic force.

As shown in fig. 3, an elastic support member 13 may be further disposed on one side of the piezoelectric actuator assembly 30, and the elastic support member 13 is fixedly disposed between the elastic vibration member 31 and the mounting groove 12 so as to make the elastic vibration member 31 and the lens barrel 20 abut against each other.

More specifically, the elastic vibration member 31 may be tightly attached to the lens barrel by the force applied by the elastic support member 13. Therefore, the elastic vibration member 31 may also be formed of another material. For example, the elastic vibration member 31 may be formed of a non-magnetic material.

Referring to fig. 4 in combination, the elastic support 13 may be coupled to the mounting groove 12 of the housing. More specifically, the elastic support 13 may be fixed to the inside of the housing 10. After the piezoelectric actuation assembly 30 is properly mounted in the mounting groove 12 of the housing 10, the elastic support member 13 should be in a compressed state to provide a corresponding pre-tightening force to the elastic vibration member 31, maintaining the close adhesion between the lens barrel 20 and the actuator 30. The piezoelectric member 32 may be bonded to the short side of the elastic vibration member 31 and provide a driving force enabling movement of the lens barrel 20.

The piezoelectric element 32 may be a single-piece partition driving structure or a multi-piece common driving structure, and the piezoelectric element 32 vibrates and drives the elastic vibration 31 to resonate and rub the lens barrel 20 under the driving of an excitation signal.

The resonance includes a first-order longitudinal vibration parallel to the optical axis and a second-order bending vibration perpendicular to the optical axis, so that the elastic vibration member 31 repeatedly stretches and contracts and each point on the surface vibrates along an elliptical track, and the elliptical track generates a friction force parallel to the optical axis, so as to drive the lens barrel to move along the optical axis of the lens.

Wherein the elliptical trajectory is inclined to the horizontal plane, and the major axis and the minor axis are not parallel to the optical axis, and the inclination angle and direction are controlled by the amplitude and phase of the excitation signal, thereby adjusting the direction of the movement of the lens barrel 20.

Referring to fig. 5 and 6, along the length direction of the elastic vibration member 31, one end of the piezoelectric member 32 is connected to the elastic vibration member 31, and the other end is provided with two piezoelectric partitions or two piezoelectric fragments with the same polarization direction. The piezoelectric element 32 can coordinate and repeatedly stretch under the action of the excitation signal, so that the elastic vibration element 31 generates the first-order longitudinal vibration and the second-order bending vibration, and the accurate driving of the camera module is realized by controlling the excitation signal, and the response speed is high.

The piezoelectric element 32 may be a rigid piezoelectric material with a predetermined polarization direction parallel to the length direction.

The polarization directions between the two piezoelectric segments or piezoelectric patches of the piezoelectric element 32 are symmetrically distributed, e.g. identical and parallel to the optical axis. Electrodes are arranged on the upper surface and the lower surface of the piezoelectric element 32; wherein the electrode on the upper surface or the lower surface is connected with the elastic vibrating piece and grounded; correspondingly, the electrodes on the lower surface or the upper surface are connected with excitation signals to respectively correspond to the two piezoelectric partitions or the two piezoelectric patches.

For example, in the present embodiment, the piezoelectric element 32 is located below the elastic vibrating element 31, and the electrode on the upper surface is connected to the elastic vibrating element and grounded; the electrodes on the lower surface are connected with excitation signals to respectively correspond to the two piezoelectric partitions or the two piezoelectric patches.

The excitation signal includes a two-phase sinusoidal signal, and one section or segment is connected to one sinusoidal signal E _a and the other section or segment is connected to the other sinusoidal signal E _b between two piezoelectric segments or piezoelectric segments of the piezoelectric element 32. The elastic vibration member 31 is grounded.

And providing the excitation signal to excite the piezoelectric actuation assembly to vibrate, otherwise, enabling the piezoelectric actuation assembly to perform static friction to block the lens barrel to perform self-locking, thereby having an anti-shake function and ensuring the stable working state of the camera module.

The piezoelectric actuation assembly 30 operates as follows:

E_a=A_Esin(2πf_Et)

E_b=A_Esin(2πf_Et+φ)

where A _E and f _E are the amplitude and frequency of the applied voltage, respectively, phi is the phase difference between E _a and E _b, and t is time.

Due to the inverse piezoelectric effect of the piezoelectric material, the piezoelectric element 32 is capable of constantly generating mechanical deformations of contraction and expansion when excited. When the frequency f _E of the applied voltage and the modal frequency of the piezoelectric actuation assembly 30 do not differ much, a corresponding modal shape of the piezoelectric actuation assembly 30 can be excited.

E _a and E _b have the same frequency and the phase difference is 90 degrees, and the piezoelectric actuating assembly 30 is correspondingly and structurally designed in an optimized mode, so that a first-order longitudinal vibration mode and a second-order bending vibration mode can be generated. After the vibration modes of the two modes are overlapped, an elliptical motion track is generated on the surface of the elastic vibration piece 31 of the piezoelectric actuation assembly 30, so that the piezoelectric actuation assembly 30 drives the lens.

The voltage amplitude of the excitation signal determines the amplitude of the elliptical trajectory, and the time sequence of the excitation signal determines the direction of elliptical inclination and the direction of movement. Preferably, the ratio of the characteristic frequency difference between the first-order longitudinal vibration and the second-order bending vibration to the frequency of the two-phase sinusoidal signal is not more than 0.03.

The driving force and the moving trajectory of the elastic vibration member 31 are transmitted to the lens barrel 20. So that the lens barrel 20 can perform linear motion along the optical axis direction, and the focusing/zooming function of the camera module head is realized.

Based on the principle of an in-plane composite mode, the piezoelectric actuation assembly does not need a mechanical conduction structure of a traditional motor such as a screw rod, a gear, a speed reducer and the like while meeting the driving force and the stroke, and the formed camera module is compact in structure and low in requirements on processing and assembly; the piezoelectric actuating assembly receives the excitation signal to vibrate and drives the elastic vibrating piece to resonate, has larger vibration energy, higher energy density and higher driving efficiency, and can provide larger output force than an inertial motor under the same volume.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Thus, the embodiments should be considered in all respects as illustrative and not restrictive. Furthermore, it is evident that the word "comprising" does not exclude other elements or steps, and that the word "a" or "an" does not exclude a plurality. The elements recited in the apparatus claims may also be embodied by one element. The terms first, second, etc. are used to denote a name, but not any particular order.

Claims (25)

1. A camera module, comprising: a lens barrel having at least one lens therein; a piezoelectric actuation assembly provided at one side of the lens barrel; the piezoelectric actuating component vibrates to rub and drive the lens barrel to move along the optical axis of the lens.

2. The camera module of claim 1, wherein the piezoelectric actuation assembly comprises a piezoelectric element and an elastic vibration element connected, the piezoelectric element vibrating and driving the elastic vibration element to resonate and rub the lens barrel.

3. The camera module of claim 2, wherein the resonance includes a first order longitudinal vibration and a second order bending vibration that are generated simultaneously to vibrate each point of the surface of the elastic vibrating member along an elliptical trajectory.

4. The camera module of claim 2, wherein the piezoelectric element is a single-piece zone drive structure or a multi-piece common drive structure.

5. The camera module of claim 4, wherein one end of the piezoelectric element is connected to the elastic vibration element along the length direction of the elastic vibration element, and two piezoelectric partitions or two piezoelectric patches with the same polarization direction are arranged at the other end of the piezoelectric element.

6. The camera module of claim 5, wherein the polarization direction is parallel to the length direction.

7. The camera module of claim 5, wherein the two piezoelectric partitions or the two piezoelectric patches are symmetrically distributed.

8. The camera module of claim 5, wherein the upper and lower surfaces of the piezoelectric element are provided with electrodes; wherein the electrode on the upper surface or the lower surface is connected with the elastic vibrating piece and grounded; the electrodes on the lower surface or the upper surface are connected with excitation signals to respectively correspond to the two piezoelectric partitions or the two piezoelectric patches.

9. The camera module of claim 2, further comprising: a housing provided with a receiving groove corresponding to the lens barrel and a mounting groove corresponding to the piezoelectric actuation assembly; wherein the piezoelectric element is fixedly arranged in the mounting groove through a soft bonding material; the elastic vibrating piece is magnetically attracted and/or abutted against the lens barrel.

10. The camera module of claim 9, wherein the material of the elastic vibrating member comprises a metallic material and/or a magnetic material, further comprising: and the magnetic component is fixedly arranged on the side wall of the lens barrel so as to magnetically attract the elastic vibrating piece.

11. The camera module of any one of claims 9 or 10, further comprising: and the elastic support piece is fixedly arranged between the elastic vibration piece and the mounting groove so as to enable the elastic vibration piece and the lens barrel to abut against each other.

12. The camera module of claim 2, wherein the elastic vibration member drives the lens barrel by point friction, line friction or surface friction.

13. The camera module of claim 12, wherein the side wall of the elastic vibrating member is fixedly provided with a ceramic hemisphere or a ceramic boss in frictional contact with the lens barrel.

14. The camera module of claim 2, wherein the elastic vibrating member has a symmetrical cross section.

15. The camera module of claim 2, wherein the material of the piezoelectric element comprises a rigid piezoelectric material.

16. The camera module of claim 1, wherein a guide structure is provided in the lens barrel to reciprocate linearly along the optical axis and to achieve focusing of the lens.

17. The camera module of claim 16, further comprising: the position detecting element feeds back position information of the lens barrel.

18. The camera module of claim 17, wherein the position detection element comprises one or a combination of a hall sensor and a capacitive grating sensor.

19. The camera module according to claim 1, wherein an inner wall of the lens barrel is coated with an antireflection material or a light shielding material.

20. The driving method of the camera module is characterized by comprising the following steps of: providing an excitation signal to the piezoelectric actuation assembly; the piezoelectric actuating component receives the excitation signal to vibrate so as to rub and drive the lens barrel to move along the optical axis of the lens arranged in the lens barrel.

21. The method of driving of claim 20, wherein the energizing signal is provided to energize the piezoelectric actuation assembly to vibrate, whereas the piezoelectric actuation assembly stiction blocks the lens barrel to self-lock.

22. The method of driving of claim 20, wherein the piezoelectric actuation assembly comprises a piezoelectric element and an elastic vibrating element connected, and the excitation signal comprises a two-phase sinusoidal signal; the piezoelectric element receives the two-phase sinusoidal signals to vibrate and drive the elastic vibration element to generate first-order longitudinal vibration and second-order bending vibration simultaneously.

23. The driving method as claimed in claim 22, wherein the two-phase sinusoidal signals have the same frequency and a phase difference of 90 °.

24. The driving method of claim 23, wherein a ratio of a characteristic frequency difference between the first-order longitudinal vibration and the second-order bending vibration to a frequency of the two-phase sinusoidal signal is not more than 0.03.

25. An electronic device, comprising: a camera module according to any one of claims 1 to 17.