Piezoelectric motor, camera module and piezoelectric motor assembly process

Abstract

The invention discloses a piezoelectric motor, a camera module and a piezoelectric motor assembly process, and belongs to the technical field of camera modules, the piezoelectric motor comprises a fixed part, a movable part movably connected with the fixed part and a driving assembly, the driving assembly comprises a pre-pressing assembly and an actuating assembly, the pre-pressing assembly comprises a buffer part and a structural part, the structural part is connected with the fixed part, and the actuating assembly is connected with the buffer part. The buffer part is arranged between the structural part and the actuating assembly and is suitable for being deformed due to extrusion of the structural part and the actuating assembly, the pre-pressing assembly applies pre-pressing force to the actuating assembly so that the actuating assembly can abut against the movable part, and therefore the actuating assembly is suitable for driving the movable part to move relative to the fixed part when receiving a driving signal. The piezoelectric motor has the advantages that the actuating assembly can be prevented from inclining relative to the movable part, the buffer part can deform to offset the pre-pressure change caused by the material tolerance and the assembly tolerance, and the consistency of the pre-pressure in a plurality of piezoelectric motors in the same batch can be improved.

Description

Technical Field

[0001] The present application relates to the field of camera module technology, and in particular to a piezoelectric motor, a camera module and a piezoelectric motor assembly process. Background Art

[0002] As users’ demand for anti-shake shooting increases, users pay more and more attention to the performance of camera anti-shake in image shooting. Users expect camera modules with high pixels, small size and anti-shake capabilities. But generally speaking, the number of camera module pixels increases with the increase of image surface, and the total track length (TTL) of the optical element will also increase with the increase of image surface. The size of optical elements or photosensitive devices will also increase, and the travel and driving force requirements of the corresponding motors will also increase accordingly. The increase in motor size leads to an increase in the size of the camera module.

[0003] A piezoelectric motor is a motor with fast response, strong driving force and high driving precision. The use of a piezoelectric motor can significantly improve the performance of the camera module. This application provides a new piezoelectric motor solution to improve shooting effects. Summary of the invention

[0004] One purpose of the present application is to provide a piezoelectric motor, which prevents the actuating component from tilting relative to the moving part by improving the pre-stressing component, thereby improving the driving effect of the piezoelectric motor.

[0005] Another object of the present application is to provide a camera module to achieve the purpose of improving shooting effects.

[0006] Another object of the present application is to provide a piezoelectric motor assembly process to improve the consistency of the pre-pressure provided by the pre-pressure assembly in multiple piezoelectric motors in the same batch.

[0007] In order to achieve one of the purposes of this application, the technical solution adopted in this application is: a piezoelectric motor applied to a camera module, comprising:

[0008] Fixings;

[0009] A movable part, the movable part is movably connected to the fixed part;

[0010] A driving assembly, the driving assembly includes a pre-stressing assembly and an actuating assembly, the pre-stressing assembly includes a buffer and a structural member, the structural member is connected to the fixed member, the buffer is arranged between the structural member and the actuating assembly, and is suitable for being deformed by the compression of the structural member and the actuating assembly, the pre-stressing assembly applies a pre-pressure to the actuating assembly so that the actuating assembly abuts against the movable member, so that the actuating assembly is suitable for driving the movable member to move relative to the fixed member when receiving a driving signal.

[0011] Preferably, the structural member includes a first mounting surface facing the buffer member, the buffer member includes a second mounting surface opposite to the first mounting surface, and a third mounting surface arranged opposite to the second mounting surface, the first mounting surface is fitted with the second mounting surface, the actuator assembly includes a piezoelectric vibrator and a friction head, the piezoelectric vibrator is fitted with the third mounting surface, a side of the piezoelectric vibrator facing away from the third mounting surface is connected to the friction head, and the friction head abuts against the movable member.

[0012] Preferably, the structural member includes a first mounting surface facing the buffer member, the buffer member includes a second mounting surface opposite to the first mounting surface, and a third mounting surface opposite to and parallel to the second mounting surface, the first mounting surface is bonded to the second mounting surface, the actuator assembly includes a flexible circuit board, a piezoelectric vibrator and a friction head, two opposite surfaces of the flexible circuit board are respectively bonded to the third mounting surface and the piezoelectric vibrator, a side of the piezoelectric vibrator facing away from the third mounting surface is connected to the friction head, and the friction head abuts against the movable member.

[0013] Preferably, the movable part is arranged in the fixed part, and the fixed part is provided with an opening penetrating through both sides of the fixed part. The structural part is arranged on the outside of the fixed part, and the size of the structural part in at least one direction is larger than the size of the opening. The buffer part and the actuating assembly pass through the opening, so that the actuating assembly can abut against the movable part.

[0014] Preferably, there is a gap between a surface of the structural member facing the buffer member and an outer side surface of the fixing member.

[0015] Preferably, the structural member is connected to the fixing member via an adhesive, and the adhesive covers at least a portion of a peripheral side of the structural member.

[0016] Preferably, the elastic coefficient of the structural member is greater than or equal to 1.2*10^5 N / m; and the thickness of the structural member is greater than or equal to 150 μm.

[0017] Preferably, the elastic modulus of the buffer component is greater than or equal to 100 KPa and less than or equal to 100 MPa; the thickness of the buffer component is greater than or equal to 50 μm and less than or equal to 800 μm.

[0018] As a preference, the buffer member is an adhesive tape, and two opposite surfaces of the buffer member are respectively bonded to the structural member and the actuating assembly.

[0019] As a preferred embodiment, the piezoelectric motor comprises:

[0020] Base;

[0021] A first frame, movably connected to the base and adapted to move relative to the base in a first direction, wherein a first driving mechanism is provided between the first frame and the base;

[0022] A second frame is movably connected to the first frame and is suitable for moving relative to the first frame along a second direction, and a second driving mechanism is provided between the second frame and the first frame;

[0023] a third frame, movably connected to the second frame and adapted to move relative to the second frame along a third direction, a third driving mechanism being provided between the third frame and the second frame;

[0024] Wherein, at least one of the first driving mechanism, the second driving mechanism, and the third driving mechanism is the driving assembly, and when the first driving mechanism is the driving assembly, the base is a fixed part and the first frame is a movable part, when the second driving mechanism is the driving assembly, the first frame is a fixed part and the second frame is a movable part, and when the third driving mechanism is the driving assembly, the second frame is a fixed part and the third frame is a movable part.

[0025] In order to achieve another purpose of the present application, the technical solution adopted in the present application is: a camera module, which includes:

[0026] The piezoelectric motor mentioned above;

[0027] A lens assembly, disposed in the piezoelectric motor;

[0028] The photosensitive component is arranged relative to the lens component.

[0029] In order to achieve another object of the present application, the technical solution adopted in the present application is: an assembly process of a piezoelectric motor, which includes the steps of:

[0030] S1. Provide a fixed part, a movable part, and a driving assembly, wherein the driving assembly includes a pre-pressing assembly and an actuating assembly, and the pre-pressing assembly includes a buffer part and a structural part;

[0031] S2, installing the movable part into the fixed part;

[0032] S3, disposing the buffer member between the structural member and the actuating assembly to form a combined body;

[0033] S4, extending the buffer member and the actuating assembly in the assembly into the opening on the fixing member, and leaving the structural member outside the opening;

[0034] S5, applying a pressure to the structural member to make the structural member approach the movable member, so that the actuating assembly abuts against the movable member, and the buffer member is squeezed and deformed by the structural member and the actuating assembly;

[0035] S6, fixing the structural member on the fixing member, and during the fixing process, continuously applying the pressure provided in step S5 to the structural member, and after the fixing of the structural member is completed, removing the pressure;

[0036] Among them, S2 and S3 are in no particular order.

[0037] Preferably, step S5 further includes the steps of: obtaining a value of the pressure applied to the structural member through a pressure sensor, and adjusting the pressure until it is the same as a preset value.

[0038] Preferably, in step S6, fixing the structural member on the fixing member specifically includes the steps of: applying glue on the circumference of the structural member and making the glue contact with the fixing member, continuously applying the pressure provided in step S5 to the structural member, and completing the fixing of the structural member after the glue is cured, and removing the pressure.

[0039] Compared with the prior art, the beneficial effects of this application are:

[0040] (1) In the prior art, the pre-pressing assembly will deform and bend, causing the actuating assembly to tilt relative to the moving part, and then the actuating assembly drives the moving part to move at different speeds relative to the fixed part in two opposite directions, affecting the driving effect of the piezoelectric motor. The present application improves the structure of the pre-pressing assembly, and the structural parts will not be significantly deformed under the action of the pre-pressing force, which can prevent the actuating assembly from tilting relative to the moving part, thereby improving the driving effect of the piezoelectric motor and thus improving the shooting effect of the camera module;

[0041] (2) Since the buffer member is deformable, the buffer member is disposed between the structural member and the actuator assembly. When the piezoelectric motor is assembled, the deformation of the buffer member can offset at least part of the pre-stress change caused by the material tolerance and the assembly tolerance.

[0042] (3) The present application also provides an assembly process for a piezoelectric motor, which can adaptively adjust the compression degree of the buffer in multiple piezoelectric motors in the same batch by improving the structure of the pre-stressing component and utilizing the deformation characteristics of the buffer, thereby improving the consistency of the pre-stress in multiple piezoelectric motors in the same batch;

[0043] (4) In the prior art, a spring sheet is generally used as a pre-stressing component, and the spring sheet is connected to the actuating component through an adhesive such as UV glue or thermosetting glue. Since the elastic modulus of the adhesive is large after curing, the piezoelectric vibrator in the actuating component and the spring sheet form a rigid whole, which will affect the vibration mode of the piezoelectric vibrator and thus affect the driving effect. The buffer member of the present application can absorb part of the deformation of the piezoelectric vibrator, which is conducive to maintaining the setting angle of the piezoelectric vibrator relative to the movable member, so that the actual motion state of the piezoelectric vibrator is close to the design value, and the influence of the external environment, such as the deformation of the pre-stressing component, on the motion of the piezoelectric vibrator is reduced;

[0044] (5) Furthermore, the buffer member can be attached between the actuator assembly and the structural member, which not only facilitates assembly, but also avoids the problem of affecting the vibration mode of the piezoelectric vibrator caused by using adhesives such as UV glue or thermosetting glue to bond the spring piece in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A cross-sectional view of a camera module in a preferred embodiment of the present application;

[0046] Figure 2 This is a schematic diagram of the exploded structure of a piezoelectric motor in a preferred embodiment of the present application;

[0047] Figure 3 This is a schematic diagram of the internal structure of a piezoelectric motor in a preferred embodiment of the present application;

[0048] Figure 4 It is a schematic diagram of the explosion structure of the pre-pressing component in the prior art;

[0049] Figure 5 It is a schematic diagram of the actuating assembly and the movable part tilting after the pre-pressing assembly is deformed in the prior art;

[0050] Figure 6 This is a structural schematic diagram of a base and a first frame in a preferred embodiment of the present application;

[0051] Figure 7 This is a schematic diagram of the structure of the first frame and the second frame in a preferred embodiment of the present application;

[0052] Figure 8 This is a schematic diagram of the structure of the second frame and the third frame in a preferred embodiment of the present application;

[0053] Fig. 9 This is a schematic diagram of the structure of three driving components and a flexible circuit board in a preferred embodiment of the present application;

[0054] Fig.10 This is a schematic diagram of the explosion structure of the pre-pressing component in another preferred embodiment of the present application;

[0055] Fig.11This is a schematic diagram of the working principle of the actuating assembly in a preferred embodiment of the present application;

[0056] Fig.12 for Figure 3 A magnified view of the local structure at point A in the middle;

[0057] Fig.13 It is a schematic diagram of the connection between the structural parts and the fixing parts;

[0058] In the figure: 1, piezoelectric motor; 2, lens assembly; 3, photosensitive assembly; 4, camera module; 10, circuit board; 20, fixed assembly; 21, base; 211, base body; 212, base ball groove; 213, base side plate; 2131, first opening; 22, shell; 221, shell body; 222, pressure plate; 2221, transverse spring; 30, movable assembly; 301, wear-resistant part; 31, first frame; 311, first frame ball groove; 312, second opening; 32, second frame; 321, protrusion; 322, second frame ball groove; 323, second frame guide groove; 33, third frame; 331, third frame guide groove; 40, driving mechanism; 401, first driving mechanism; 4011, first structural member; 4012, first buffer member; 4013, first Piezoelectric vibrator; 4014, first friction head; 402, second driving mechanism; 4021, second structural member; 4022, second buffer member; 4023, second piezoelectric vibrator; 403, third driving mechanism; 4031, third structural member; 4032, third buffer member; 4033, third piezoelectric vibrator; 4034, third friction head; 41, pre-pressing assembly; 410, spring; 411, structural member; 4111, first mounting surface; 412, buffer member; 4122, second mounting surface; 4123, third mounting surface; 42, actuating assembly; 421, flexible circuit board; 422, piezoelectric vibrator; 4221, first side electrode; 4222, second side electrode; 4223, third side electrode; 4224, fourth side electrode; 423, friction head; 50, supporting mechanism; 61, adhesive. DETAILED DESCRIPTION

[0059] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0060] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present application.

[0061] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0062] The terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0063] Reference Figure 1 , an exemplary camera module including a piezoelectric motor 1 will be described, which includes a piezoelectric motor 1, a lens assembly 2 and a photosensitive assembly 3. The lens assembly 2 has an optical axis, and the piezoelectric motor 1 is arranged outside the lens assembly 2, the photosensitive assembly 3 is located below the lens assembly 2, and the lens assembly 2 is held on the photosensitive path of the photosensitive assembly 3. The lens assembly 2 is used to collect imaging light from the subject and transmit the imaging light to the photosensitive assembly 3, and the photosensitive assembly 3 is used to receive the light passing through the lens assembly 2 to generate image information.

[0064] The piezoelectric motor 1 can drive the lens assembly 2 to move along the optical axis to adjust the distance between the lens assembly 2 and the photosensitive assembly 3 to achieve the focusing function; the piezoelectric motor 1 can drive the lens assembly 2 to move in the plane direction perpendicular to the optical axis to make the lens assembly 2 translate relative to the photosensitive assembly 3 to achieve the anti-shake function.

[0065] Reference Figure 2 , Attachment Figure 3, an exemplary piezoelectric motor 1 will be described. The present application proposes a piezoelectric motor 1, which includes a circuit board 10, a fixed component 20, a movable component 30, at least one driving mechanism 40, and a supporting mechanism 50. Among them, the movable component 30 is accommodated in the fixed component 20, the driving end of at least one driving mechanism 40 abuts against the side wall of the movable component 30, and the movable component 30 is movably supported in the fixed component 20 by the supporting mechanism 50, so that when the movable component 30 is driven by the driving force of the driving mechanism 40 and moves, the friction resistance is small.

[0066] A portion of the circuit board 10 is fixedly connected to the fixed component 20, and another portion of the circuit board 10 is fixedly connected to the movable component 30. The portion of the circuit board 10 fixed to the fixed component 20 and the portion of the circuit board 10 fixed to the movable component 30 are bent and have a certain flexibility, so that when the movable component 30 moves, the circuit board 10 has a small blocking effect on the movement of the movable component 30. The circuit board 10 is electrically connected to the driving mechanism 40 to realize power supply for the driving mechanism 40.

[0067] The fixed assembly 20 includes a base 21 and a housing 22, wherein the housing 22 is located on the upper side of the base 21. The base 21 and the housing 22 are engaged with each other to achieve a fixed connection, and a receiving cavity is formed inside the housing 22 to accommodate components such as the movable assembly 30, the circuit board 10, the driving mechanism 40, and the supporting mechanism 50. The housing 22 can prevent the internal components from being impacted by the outside world and causing damage to the parts.

[0068] Reference Figure 2 , Attachment Figure 3 As shown, the circuit board 10 fixed on the base 21 is electrically connected to the photosensitive component 3 in a manner of leading out the pins 15 , so that the circuit board 10 in the photosensitive component 3 can perform signal control on the piezoelectric motor 1 .

[0069] The lower end of the movable component 30 and the upper surface of the base 21 are movably connected together by at least one supporting mechanism 50, and the upper end of the movable component 30 and the lower surface of the housing 22 are movably connected together by at least one supporting mechanism 50. In some optional embodiments, supporting mechanisms 50 are provided at both the upper and lower ends of the movable component 30, which are movably connected to the base 21 and the housing 22, respectively. The supporting mechanisms 50 support the gap height between the movable component 30 and the base 21 and the housing 22, so that the movable component 30 is not prone to shaking or tilting in the optical axis direction relative to the base 21 and the housing 22, thereby increasing the impact resistance and improving the product reliability.

[0070] Specifically, the movable assembly 30 includes a first frame 31, a second frame 32, and a third frame 33. The first frame 31 is located on the upper side of the base 21. The first frame 31 and the base 21 are movably connected together through at least one supporting mechanism 50. The second frame 32 is located inside the first frame 31. The upper end of the second frame 32 and the lower surface of the housing 22 are movably connected together through at least one supporting mechanism 50. The movable connection between the movable assembly 30 and the fixed assembly 20 is realized.

[0071] In some optional embodiments, at least one supporting mechanism 50 is provided between the first frame 31 and the base 21, and the first frame 31 can have the freedom to move in a first direction relative to the base 21. The second frame 32 is provided inside the first frame 31, and the second frame 32 and the first frame 31 are movably connected together through at least one supporting mechanism 50, and the second frame 32 has the freedom of movement in a second direction relative to the first frame 31. The third frame 33 is provided inside the second frame 32, and the third frame 33 and the second frame 32 are movably connected together through at least one supporting mechanism 50, and the third frame 33 has the freedom of movement in a third direction relative to the second frame 32.

[0072] Specifically, the driving mechanism 40 includes a first driving mechanism 401, a second driving mechanism 402, and a third driving mechanism 403. The first frame 31 is movably connected to the base 21 and is suitable for moving in a first direction relative to the base 21. The first driving mechanism 401 is provided between the first frame 31 and the base 21 to drive the first frame 31 to move relative to the base 21. The second frame 32 is movably connected to the first frame 31 and is suitable for moving in a second direction relative to the first frame 31. The second driving mechanism 402 is provided between the second frame 32 and the first frame 31 to drive the second frame 32 to move relative to the first frame 31. The third frame 33 is movably connected to the second frame 32 and is suitable for moving in a third direction relative to the second frame 32. The third driving mechanism 403 is provided between the third frame 33 and the second frame 32 to drive the third frame 33 to move relative to the second frame 32.

[0073] Specifically, the direction of the freedom of movement of the second frame 32 relative to the first frame 31 is orthogonal to the direction of the freedom of movement of the first frame 31 relative to the base 21, that is, the first direction is orthogonal to the second direction, so that in the present application, the second frame 32 has the ability to move in the plane direction perpendicular to the optical axis relative to the base 21, and when anti-shake is performed, the second frame 32 can be driven to move in the plane direction relative to the base 21. That is, the piezoelectric motor 1 can realize the optical anti-shake function. Further, the third frame 33 has the freedom of movement in the third direction relative to the second frame 32, and the third direction is a direction parallel to the optical axis direction. In other words, the driving direction of the second drive mechanism 402 is orthogonal to the driving direction of the first drive mechanism 401, and the driving direction of the third drive mechanism 403 is orthogonal to the driving direction of the first drive mechanism 401 and the driving direction of the second drive mechanism 402, respectively, so that the third frame 33 can move in the plane perpendicular to the optical axis to achieve anti-shake, and can also move along the optical axis to achieve focusing processing. Therefore, in the present embodiment, the camera module 4 with the piezoelectric motor 1 can not only satisfy the horizontal movement required for the anti-shake photography of the camera module, but also perform the focusing process of the picture.

[0074] In the present application, the driving mechanism 40 is piezoelectrically driven, which requires a friction connection relationship between the driving end and the driven part. By reducing the resistance of the driven part during movement, the loss of the piezoelectric motor 1 in overcoming the friction resistance can be reduced. The support component 50 is provided to not only improve the parallelism of the movement of the driven part, but also change the friction mode of the driven part to reduce the friction resistance of the driven part during movement. For example, when the support component 50 is set as a ball, the driven part is subjected to point friction, or, when the support component 50 is a guide rod, the driven part is subjected to line friction. The friction force of point friction or line friction is smaller than that of surface friction, thereby reducing the friction loss of the driving mechanism 40 and increasing the service life of the driving mechanism 40 and the piezoelectric motor 1.

[0075] For easier understanding, refer to the attached Figure 3 Schematically, the first direction is the x-axis direction in the figure, the second direction is the y-axis direction perpendicular to the x-axis direction and forming a horizontal plane with the x-axis direction, and the third direction is the z-axis direction perpendicular to the horizontal plane, and the z-axis direction is parallel to the optical axis.

[0076] Each driving mechanism 40 includes a respective pre-stressing component 41 and an actuating component 42. The pre-stressing component 41 applies a pre-stressing force to the actuating component 42 so that the actuating component 42 abuts against the driven part, so that the actuating component 42 is suitable for driving the driven part to move when receiving a driving signal. The actuating component 42 includes a piezoelectric vibrator 422 and a friction head 423. The friction head 423 is arranged on the side of the piezoelectric vibrator 422 facing away from the pre-stressing component 41. The friction head 423 abuts against the driven part as the driving end of the driving mechanism 40. Among them, the piezoelectric vibrator 422 is a substrate that has an inverse piezoelectric effect and shrinks or expands according to the polarization direction and the electric field direction. It can be used by polarizing the substrate in the thickness direction of single crystal, polycrystalline ceramics, polymers, etc. The inverse piezoelectric effect refers to the application of an electric field in the polarization direction of the dielectric, and the dielectric undergoes mechanical deformation when a potential difference is generated. The piezoelectric vibrator 422 has the function of ultrasonic oscillation, and can realize the deflection reciprocating motion or elliptical motion on the specially arranged electrode layer, so as to achieve the effect of driving the driving end of the driving mechanism 40 .

[0077] For the convenience of description, the driven part is recorded as a movable part, and the frame or base 21 that carries the driven part and is arranged adjacent to the driven part is recorded as a fixed part. In the present application, the piezoelectric motor 1 includes a movable part, a fixed part and a driving mechanism 40, wherein the movable part is movably connected to the fixed part, and the driving mechanism 40 includes a pre-stressing component 41 and an actuating component 42, and the actuating component 42 includes at least one piezoelectric vibrator 422. The pre-stressing component 41 is connected to the fixed part and the actuating component 42, and applies a pre-stressing force to the actuating component 42 so that the actuating component 42 abuts against the movable part, so as to drive the movable part to move relative to the fixed part by piezoelectric drive.

[0078] Reference Figure 4 In the prior art, the pre-stressing component is usually provided as a spring sheet 410. The spring sheet 410 is provided on the side of the piezoelectric vibrator 422 away from the movable part. The end of the spring sheet 410 is connected to the fixing part. The middle part of the spring sheet 410 is pressed against the side of the piezoelectric vibrator 422. The pre-stressing force is provided by the elastic force of the spring sheet 410. Since the spring sheet 410 has a small rigidity and is easy to deform, the spring sheet 410 will bend after providing the pre-stressing force, and an inclination angle will be generated in the middle part of the spring sheet 410, which will cause the piezoelectric vibrator 422 to have an inclination angle other than the preset angle relative to the movable part. For example, in an ideal situation, the spring sheet 410 is provided parallel to the piezoelectric vibrator 422 to provide a pre-stressing force perpendicular to the abutting surface of the movable part. However, in actual use, the spring sheet 410 bends so that the piezoelectric vibrator 422 is tilted relative to the movable part. This will cause the actuator assembly 42 to drive the movable part to move in two opposite directions relative to the fixed part, and the movement speeds will be inconsistent, affecting the driving effect of the piezoelectric motor 1, and will affect the focus function and anti-shake function, resulting in a worse shooting effect of the camera module.

[0079] At the same time, considering that the moving parts, fixed parts and other components have certain material tolerances during processing and forming, and there are certain assembly tolerances when these components are assembled into a complete piezoelectric motor 1, the material tolerance and assembly tolerance will directly affect the deformation degree of the spring 410, and then affect the pre-pressure, resulting in differences in the pre-pressure of each piezoelectric motor 1 in the same batch of piezoelectric motors 1. The pre-pressure is the pressure of the actuating component 42 against the moving part. The size and direction of the pre-pressure will affect the size of the friction between the actuating component 42 and the moving part, and the actuating component 42 actually drives the moving part by this friction. In other words, the existence of material tolerance and assembly tolerance leads to the problem of inconsistent pre-pressure of multiple piezoelectric motors 1 in the same batch, resulting in different driving effects of each actuating component 42 on the moving part.

[0080] Furthermore, in the prior art, the spring 410 is bonded to the flexible circuit board 421 disposed on one side of the piezoelectric vibrator 422 in the actuator assembly 42 by an adhesive such as UV glue or thermosetting glue. After the adhesive is cured, the elastic modulus is relatively large, which will hinder the deformation of the piezoelectric vibrator 422 on the one hand, and on the other hand, will cause the piezoelectric vibrator 422 and the spring 410 to form a rigid whole, changing the vibration mode of the piezoelectric vibrator 422. Under the influence of these two aspects, the driving force of the actuator assembly 42 is relatively low, affecting the driving effect of the piezoelectric motor 1. It should be pointed out that the elastic modulus of the commonly used UV glue or thermosetting glue after curing is greater than 1Gpa, which is sufficient to cause the piezoelectric vibrator 422 and the spring 410 to form a rigid whole, changing the vibration mode of the vibrator.

[0081] In order to solve the above problems, the present application improves the structure of the pre-pressing assembly 41 and other related components.

[0082] The present application provides a new piezoelectric motor 1 solution: a piezoelectric motor 1 applied to a camera module, comprising: a fixed part, a movable part and a driving assembly, the movable part is movably connected to the fixed part, the driving assembly comprises a pre-stressing assembly 41 and an actuating assembly 42, the pre-stressing assembly 41 comprises a structural part 411 and a buffer part 412, the structural part 411 is connected to the fixed part, the buffer part 412 is arranged between the structural part 411 and the actuating assembly 42, and is suitable for being deformed by being squeezed by the structural part 411 and the actuating assembly 42, the pre-stressing assembly 41 applies a pre-stress to the actuating assembly 42 so that the actuating assembly 42 abuts against the movable part, so that the actuating assembly 42 is suitable for driving the movable part to move relative to the fixed part when a driving signal is received.

[0083] In this solution, firstly, the structural member 411 plays a rigid supporting role, and the structural member 411 will not be significantly deformed under the action of pre-pressure, which can prevent the actuator assembly 42 from tilting relative to the movable part, improve the driving effect of the piezoelectric motor 1, and further improve the shooting effect of the camera module. Secondly, since the buffer 412 can be deformed, the buffer 412 is set between the structural member 411 and the actuator assembly 42. When assembling the piezoelectric motor 1, the deformation of the buffer 412 can offset at least part of the pre-pressure change caused by the material tolerance and assembly tolerance. For example, when one piezoelectric motor 1 has a tolerance of 10um and the other piezoelectric motor 1 has a tolerance of 100um, under the deformation buffering of the buffer 412, the pre-pressure deviation value of the two is less than ten times the difference. 3. The buffer member 412 can absorb part of the deformation of the piezoelectric vibrator 422, which is beneficial to maintaining the setting angle of the piezoelectric vibrator 422 relative to the movable part, so that the actual movement state of the piezoelectric vibrator 422 is close to the design value, and the influence of the external environment, such as the deformation of the pre-stressing component 41, on the movement of the piezoelectric vibrator 422 is reduced. Furthermore, the buffer member 412 can be attached between the actuator component 42 and the structural member 411, which is not only convenient for assembly, but also avoids the problem of affecting the vibration mode of the piezoelectric vibrator 422 caused by using adhesives such as UV glue or thermosetting glue to bond the spring piece 410 in the prior art.

[0084] The actuating assembly 42 generally includes a piezoelectric vibrator 422 and a friction head 423. The side of the piezoelectric vibrator 422 facing away from the pre-pressing assembly 41 is connected to the friction head 423. The pre-pressing force provided by the pre-pressing assembly 41 to the actuating assembly 42 acts on the movable part through the piezoelectric vibrator 422 and the friction head 423. In other words, the friction head 423 abuts against the movable part under the action of the pre-pressing force.

[0085] Considering that the piezoelectric vibrator 422 needs to be powered to work, in some optional embodiments, the actuator assembly 42 also includes a flexible circuit board 421 that provides power to the piezoelectric vibrator 422, and the flexible circuit board 421 is arranged between the piezoelectric vibrator 422 and the buffer 412. The flexible circuit board 421 (FPC) is a highly reliable and highly flexible printed circuit board made of polyimide or polyester film as a substrate. FPC is also known as a soft circuit board or a flexible circuit board. It is popular for its excellent properties such as light weight, thin thickness, and free bending and folding. Fig. 9 As shown, the flexible circuit board 421 can be a local structure of the circuit board 10 , or can be another one or more circuit boards electrically connected to the circuit board 10 .

[0086] In some optional embodiments, the structural member 411 includes a first mounting surface 4111 facing the buffer member 412, the buffer member 412 includes a second mounting surface 4122 opposite to the first mounting surface 4111, and a third mounting surface 4123 arranged opposite to the second mounting surface 4122, the first mounting surface 4111 is fitted with the second mounting surface 4122, the actuator assembly 42 includes a piezoelectric vibrator 422 and a friction head 423, the piezoelectric vibrator 422 is fitted with the third mounting surface 4123, a side of the piezoelectric vibrator 422 facing away from the third mounting surface 4123 is connected to the friction head 423, and the friction head 423 abuts against the movable part.

[0087] In another optional embodiment, refer to Fig.10 As shown, the actuator assembly 42 also includes a flexible circuit board 421 for providing power to the piezoelectric vibrator 422. Specifically, the structural member 411 includes a first mounting surface 4111 facing the buffer member 412, the buffer member 412 includes a second mounting surface 4122 opposite to the first mounting surface 4111, and a third mounting surface 4123 opposite to and parallel to the second mounting surface 4122, the first mounting surface 4111 is bonded to the second mounting surface 4122, the actuator assembly 42 includes a flexible circuit board 421, a piezoelectric vibrator 422 and a friction head 423, two opposite surfaces of the flexible circuit board 421 are bonded to the third mounting surface 4123 and the piezoelectric vibrator 422, a surface of the piezoelectric vibrator 422 away from the third mounting surface 4123 is connected to the friction head 423, and the friction head 423 is in contact with the movable member.

[0088] In some optional embodiments, the pre-pressing assembly 41 includes a structural member 411 and a buffer member 412, and the buffer member 412 is directly attached between the structural member 411 and the actuating assembly 42. In other words, the actuating assembly 42 is attached to the structural member 411 through the buffer member 412. Specifically, the movable member is arranged in the fixed member, and the fixed member is provided with an opening that runs through the inner and outer sides of the fixed member. The structural member 411 is arranged outside the fixed member, and the size of the structural member 411 in at least one direction is larger than the size of the opening. In other words, the size of the structural member 411 in one direction parallel to its first mounting surface 4111 is larger than the size of the opening, so that the structural member 411 can be fixed outside the fixed member, and the buffer member 412 and the actuating assembly 42 pass through the opening, so that the actuating assembly 42 can abut against the movable member. It should be understood that the length and width of the opening are greater than or equal to the length and width of the actuating assembly 42 and the buffer member 412, so that the actuating assembly 42 and the buffer member 412 can pass through the opening so that the actuating assembly 42 can abut against the movable member. The piezoelectric vibrator 422 is accommodated in the opening, reducing the size increase caused by the external placement of the piezoelectric vibrator 422, thereby reducing the size of the piezoelectric motor 1. It should be noted that in the present application, the size of the opening on the fixing member and other components of the driving assembly, such as the buffer 412 and the piezoelectric vibrator 422, refers to the size of each component projected on the structural member 411 along the installation direction between the actuating assembly 42, the buffer 412, and the structural member 411.

[0089] More specifically, the buffer member 412 is in the form of a thin sheet, which is respectively used to be parallel to the two side surfaces attached to the actuating assembly 42 and the structural member 411, that is, the second mounting surface 4122 on the outside of the buffer member 412 is arranged in parallel with the third mounting surface 4123 on the inside, and the side of the structural member 411 facing the buffer member 412 is a plane, which is the first mounting surface 4111. The first mounting surface 4111 is connected to the outer side surface of the fixing member and the actuating assembly 42, so that the actuating assembly 42 can be kept parallel to the structural member 411, thereby maintaining the parallelism of the actuating assembly 42 relative to the movable member and the fixed member, so that the actuating assembly 42 is arranged in parallel between the movable member and the fixed member.

[0090] Considering that the buffer 412 can spontaneously generate adaptive deformation, which can offset at least part of the material tolerance and assembly tolerance and reduce the difference in preload among multiple piezoelectric motors 1 in the same batch, the consistency of the preload of each piezoelectric motor 1 still needs to be improved.

[0091] To this end, the present application adjusts the pressure applied to the structural member 411 during the assembly process of the piezoelectric motor 1, and adjusts the degree of compression and deformation of the buffer member 412 during the process of gradually moving the structural member 411 closer to the movable member, thereby setting the pre-stress of the piezoelectric motor 1 at a preset value in the initial state, and then fixes the structural member 411 on the fixing member, and fixes the spacing between the structural member 411 and the outer side surface of the fixing member to maintain the preset size of the pre-stress, so that the consistency of the pre-stress in multiple piezoelectric motors 1 is significantly improved. In order to more fully disclose the scheme of the piezoelectric motor 1 of the present application, the corresponding assembly process of the piezoelectric motor 1 will be disclosed later.

[0092] Combination Fig.12 As shown, in view of the differences in material tolerances and assembly tolerances between different piezoelectric motors 1, in a piezoelectric motor 1 with a smaller tolerance, when the structural member 411 moves a shorter distance toward the movable member, the preload value generated by the preload assembly 41 has reached a preset value, and at this time, there is a gap a between the side of the structural member 411 facing the buffer member 412 and the outer side surface of the fixing member. In a specific embodiment, the side of the structural member 411 facing the buffer member 412 is a first mounting surface 4111, which is a plane, and there is a certain spacing distance between the first mounting surface 4111 and the outer side surface of the fixing member, so that a gap a is formed between the two.

[0093] In some optional embodiments, such as Fig.13 As shown, the structural member 411 is connected to the fixing member through an adhesive 61, and the adhesive covers at least a portion of the peripheral side of the structural member 411. It can be understood that if the adhesive is set between the side of the structural member 411 facing the fixing member and the outer side of the fixing member, then when applying the glue, it is necessary to first expose the side of the structural member 411 facing the fixing member and the outer side of the fixing member in order to apply the glue, which is inconvenient to operate and is also easy to hinder the assembly step of adjusting the pre-pressure by applying a force toward the movable member to the structural member 411. The method of coating the adhesive on the peripheral side of the structural member 411 is easy to operate and efficient, and is convenient for use in actual assembly. It should be understood that the adhesive 61 covers the outer side of the fixing member and at least a portion of the peripheral side of the structural member 411 at the same time.

[0094] As an improvement, in some optional embodiments, when the adhesive is coated on the periphery of the structural member 411, the adhesive extends to the side of the structural member 411 that is not facing the fixed member. In other words, part of the adhesive is arranged in the installation direction of the actuating assembly 42, the buffer member 412, and the structural member 411. Such an arrangement enables the adhesive to have a better fixing effect, and tightly presses the structural member 411 in the direction of the fixed member and the movable member, thereby continuously and stably providing pre-pressure.

[0095] As a supplement, in a specific embodiment, the size of the structural member 411 in a specific direction exceeds the size of the opening on the fixing member. The structural member 411 is rectangular, and along its length direction, the middle part of the structural member 411 is arranged relative to the opening, and the two ends of the structural member 411 are opposite to the shell around the opening on the fixing member. The adhesive is coated on both ends of the structural member 411 so that the structural member 411 can be connected to the fixing member. In other specific embodiments, the structural member 411 is set to other shapes. The dimensions of the structural member 411 may be larger than the size of the opening in multiple directions, and multiple ends or the entire periphery of the structural member 411 are opposite to the shell around the opening. The adhesive is coated on at least two scattered points on the side of the structural member 411 to achieve the connection between the structural member 411 and the fixing member.

[0096] In a specific embodiment, the adhesive is UV glue. UV glue, also known as ultraviolet glue, is a single-component UV visible light-cured modified acrylic structural adhesive. UV glue is a type of adhesive that is cured by ultraviolet light irradiation. In a specific embodiment, when assembling the piezoelectric motor 1, UV glue can be first applied to the side of the structural member 411 facing the fixed member and the outer side of the fixed member, and then the glue is cured by UV light, i.e. ultraviolet irradiation, to complete the fixation of the structural member 411. At this time, the distance between the structural member 411 and the fixed member is determined, and the pre-pressure is at the initial preset value. Of course, the UV glue can also be coated on the peripheral side of the structural member 411 so that the UV glue is in contact with the outer side of the fixed member at the same time.

[0097] In a specific embodiment, the adhesive is UV thermosetting adhesive, which is a type of adhesive that can be cured by ultraviolet rays, heating, or baking. In a specific embodiment, when assembling the piezoelectric motor 1, the UV thermosetting adhesive can be first applied to the structural member 411 and the fixing member and irradiated with ultraviolet rays to preliminarily fix the structural member 411 on the fixing member. After the spacing between the structural member 411 and the fixing member is determined, heating is performed to achieve complete curing of the UV thermosetting adhesive.

[0098] In some optional embodiments, the structural member 411 is fixed to the outer surface of the fixing member by welding, hot riveting, etc.

[0099] In a specific embodiment, the elastic coefficient of the structural member 411 is greater than or equal to 1.2*10^5N / m, so that the structural member 411 will not be significantly deformed under the reaction of the pre-pressure. For example, there will be no significant deformation when at least 300g of pre-pressure is applied, thereby preventing the actuator assembly 42 from tilting, and further avoiding the situation where the actuator assembly 42 drives the movable part to move in two directions at inconsistent speeds.

[0100] In a specific implementation, the thickness of the structural member 411 is greater than or equal to 150 μm. For example, in a specific example, the material of the structural member 411 is steel, and the structural member 411 is implemented as a steel plate with a thickness of 200 μm. It can be measured that the structural member 411 has no obvious deformation after applying the pre-pressure.

[0101] It can be understood that the structural member 411 serves as a rigid support member, and the buffer member 412 serves as a buffer element with adjustable deformation degree. The elastic modulus of the structural member 411 is greater than the elastic modulus of the buffer member 412. The buffer member 412 is easier to deform than the structural member 411, and can adaptively produce different degrees of shrinkage deformation according to the tolerances of different sizes in different piezoelectric motors 1, thereby reducing the difference in pre-stress of each piezoelectric motor 1 under different tolerances. Correspondingly, it can be understood that the thicker the thickness of the buffer member 412 and the lower the elastic modulus, the higher its tolerance to material tolerance and assembly tolerance, so that the influence of material tolerance and assembly tolerance on the pre-stress of the piezoelectric motor 1 is lower. The solution using the spring 410 in the prior art is limited by the deformation of the spring 410 itself, and the pre-stress generated by it has a large fluctuation due to the influence of material tolerance. In addition, the buffer 412 can absorb part of the vibration deformation of the piezoelectric vibrator 422, maintain the parallelism of the piezoelectric vibrator 422 relative to the movable part, and solve the problem in the prior art that the vibration of the piezoelectric vibrator 422 induces the vibration of the structural member 411, thereby playing a "partitioning" role.

[0102] In a specific embodiment, the elastic modulus of the buffer 412 is greater than or equal to 100 KPa and less than or equal to 100 MPa. When the elastic modulus of the buffer 412 is too large, the buffer 412 is difficult to deform, and when the elastic modulus of the buffer 412 is too low, it is difficult for the preload assembly 41 to provide sufficient preload to the actuating assembly 42. After testing, when the elastic modulus of the buffer 412 is greater than or equal to 100 KPa and less than or equal to 100 MPa, the buffer 412 is just in a relatively suitable range, and the buffer 412 is moderately soft and hard, and can provide a preload within the required range.

[0103] In a specific embodiment, the thickness of the buffer 412 is greater than or equal to 50 μm and less than or equal to 800 μm. When the thickness of the buffer 412 is too small, the deformation range of the buffer 412 is small, which is not enough to cope with the differences in material tolerances and assembly tolerances in each piezoelectric motor 1. When the thickness of the buffer 412 is too large, it will cause the thickness of the entire drive assembly to increase, so that the overall size of the piezoelectric motor 1 increases, which is contrary to the current miniaturization requirements of the camera module. After actual measurement and experimental simulation of the tolerances in the piezoelectric motor 1, when the thickness of the buffer 412 is within this range, it is basically possible to eliminate the tolerances in each piezoelectric motor 1, and the size of the piezoelectric motor 1 in the thickness direction of the buffer 412 is controlled to be smaller.

[0104] Further considering the elastic modulus requirements of the buffer 412 and the size requirements of the piezoelectric motor 1, the elastic modulus of the buffer 412 ranges from 100KPa to 20MPa, and the thickness of the buffer 412 ranges from 50μm to 400μm, both inclusive. For example, in a specific example, the elastic modulus of the buffer 412 is 450KPa and the thickness is 260μm.

[0105] In some optional embodiments, the buffer 412 can be implemented as a tape, and the two opposite surfaces of the buffer 412 are respectively bonded to the structural member 411 and the actuating assembly 42. It can be understood that the two opposite surfaces of the buffer 412 here are the second mounting surface 4122 and the third mounting surface 4123 mentioned above. Compared with the glue connection method, the tape connection has at least three advantages: first, it avoids the use of high elastic modulus glue, such as UV glue with an elastic modulus of at least 1GPa after curing, which will affect the deformation of the buffer 412 and the piezoelectric vibrator 422; second, it is easy to operate, and the actuating assembly 42 can be directly attached to the structural member 411 without the steps of coating glue and curing glue; third, the parallelism of the tape is relatively good, and it can provide parallel second mounting surface 4122 and third mounting surface 4123, which is conducive to improving the parallelism of the actuating assembly 42 relative to the fixed part and the movable part.

[0106] In a specific implementation, the size of the buffer 412 can be smaller than, equal to, or larger than the size of the piezoelectric vibrator 422, as long as the buffer 412 is filled between the piezoelectric vibrator 422 and the structural member 411. Similarly, the specific shape and number of the buffer 412 do not need to be limited. For example, two pieces of tape can be stacked and used as the buffer 412, or two pieces of tape can be spaced apart along the length direction of the structural member 411.

[0107] In some optional embodiments, the size of the buffer 412 is larger than the size of the actuator assembly 42, specifically larger than the size of the piezoelectric vibrator 422 in the actuator assembly 42, so that the buffer 412 can completely fill the space between the actuator assembly 42 and the structural member 411, which is beneficial to ensure the strength of the connection structure and the installation parallelism of the actuator assembly 42.

[0108] In more detail, in this embodiment, the piezoelectric motor 1 includes a base 21, a first frame 31, a second frame 32, and a third frame 33. The first frame 31 is movably connected to the base 21 and is suitable for moving in a first direction relative to the base 21, and a first driving mechanism 401 is provided between the first frame 31 and the base 21. The second frame 32 is movably connected to the first frame 31 and is suitable for moving in a second direction relative to the first frame 31, and a second driving mechanism 402 is provided between the second frame 32 and the first frame 31. The third frame 33 is movably connected to the second frame 32 and is suitable for moving in a third direction relative to the second frame 32, and a third driving mechanism 403 is provided between the third frame 33 and the second frame 32.

[0109] Among them, at least one of the first driving mechanism 401, the second driving mechanism 402, and the third driving mechanism 403 and the surrounding related parts are improved to the above-mentioned driving assembly and related structures. And it is easy to understand that: when the first driving mechanism 401 is improved to the driving assembly, the base 21 is the fixed part and the first frame 31 is the movable part; when the second driving mechanism 402 is the driving assembly, the first frame 31 is the fixed part and the second frame 32 is the movable part; when the third driving mechanism 403 is the driving assembly, the second frame 32 is the fixed part and the third frame 33 is the movable part.

[0110] In other words, there may be multiple driving mechanisms 40 in a piezoelectric motor 1. The present application improves the pre-stressing assembly 41 and related components in at least one of the driving mechanisms 40, and for the sake of distinguishing the description, the improved driving mechanism 40 is referred to as a driving assembly. Similarly, for the sake of distinction, the pre-stressing assembly 41 and the actuating assembly 42 in the first driving mechanism 401 are respectively referred to as a first pre-stressing assembly and a first actuating assembly. When the first driving mechanism 401 is improved to a driving assembly, the first pre-stressing assembly includes a first structural member 4011 and a first buffer member 4012, and the piezoelectric vibrator 422 and the friction head 423 in the first actuating assembly are referred to as a first piezoelectric vibrator 4013 and a first friction head 4014. Similarly, the second driving mechanism 402 includes a second pre-stressing assembly and a second actuating assembly. When the second driving mechanism 402 is improved to a driving assembly, the second pre-stressing assembly includes a second structural member 4021 and a second buffer member 4022, and the second actuating assembly includes a second piezoelectric vibrator 4023 and a second friction head 4024. The third driving mechanism 403 includes a third pre-pressing assembly and a third actuating assembly. When the third driving mechanism 403 is set as the above driving assembly, the third pre-pressing assembly includes a third structural member 4031 and a third buffer member 4032, and the third actuating assembly includes a third piezoelectric vibrator 4033 and a third friction head 4034. It should be specifically noted that in this application, when it is not specified whether the first pre-pressing assembly, the second pre-pressing assembly, or the third pre-pressing assembly is currently referred to, the term "pre-pressing assembly" may refer to any one of them, and the same applies to the terms "structural member", "buffer member", "driving mechanism", "actuating assembly", "piezoelectric vibrator", "friction head", "side electrode", "opening", etc.

[0111] In some optional embodiments, Figure 6 As shown, when the first driving mechanism 401 is improved into a driving assembly, the base 21 and the first frame 31 form a group of fixed parts and movable parts.

[0112] Specifically, the base 21 includes a base body 211 and a base side plate 213 extending upward from at least two sides of the base body 211, wherein the base body 211 is located at the bottom side of the base 21, plays the role of base support, and the base body 211 is positioned and fixed with the housing 22. The base body 211 can provide an installation reference for the components set on the base 21. The base body 211 and / or the base side plate 213 are provided with a base ball groove 212. The base 21 and the first frame 31 are movably connected by the balls set in the base ball groove 212, so that the first frame 31 can move relative to the base 21 along the first direction.

[0113] The end of the first structural member 4011 in the first pre-stressing assembly is connected to the outer wall of the base side plate 213, and the first actuating assembly is attached to the middle part of the first structural member 4011 through the first buffer member 4012, and the first buffer member 4012 and the first actuating assembly pass through the first opening 2131 on the base side plate 213. The first pre-stressing assembly applies a pre-stress to the first piezoelectric vibrator 4013 in the first actuating assembly and applies the pre-stress to the outer surface of the side wall of the first frame 31 through the first friction head 4014 on the first piezoelectric vibrator 4013. When the first piezoelectric vibrator 4013 is deformed, it drives the first friction head 4014 to move, so that the first friction head 4014 pushes the first frame 31 to move relative to the base 21 along the first direction through the friction force between the first friction head 4014 and the side wall of the first frame 31. The first buffer member 4012 is arranged between the first structural member 4011 and the first piezoelectric vibrator 4013. The first structural member 4011 plays a rigid supporting role for the first actuating assembly. The first buffer member 4012 can offset at least part of the prestress change caused by the material tolerance and assembly tolerance brought by the base side plate 213 and the side wall of the first frame 31, and absorb part of the deformation of the first piezoelectric vibrator 4013. It can prevent the first actuating assembly from tilting relative to the first frame 31 and is conducive to the vibration mode excitation of the first piezoelectric vibrator 4013. It has the effect of enhancing the driving effect of the piezoelectric motor 1 in the first direction and improving the consistency of the prestress provided by the first prestressing assembly between different piezoelectric motors 1.

[0114] In some optional embodiments, Figure 7 As shown, when the second driving mechanism 402 is improved into a driving assembly, the first frame 31 and the second frame 32 form a group of fixed parts and movable parts.

[0115] Specifically, a first frame ball groove 311 is provided on the first frame 31, and the top of the second frame 32 extends outward to form a protrusion 321 opposite to the first frame ball groove 311, and the lower surface of the protrusion 321 abuts against the balls in at least part of the first frame ball groove 311. By means of the balls arranged in the first frame ball groove 311, the first frame 31 and the second frame 32 are movably connected to each other, and the second frame 32 can move along the second direction relative to the first frame 31, and the connection structure is simple and easy to assemble.

[0116] The end of the second structural member 4021 in the second pre-stressing assembly is connected to the outer surface of the first frame 31, and the second actuating assembly is attached to the middle part of the second structural member 4021 through the second buffer member 4022, and the second buffer member 4022 and the second actuating assembly pass through the second opening 312 on the first frame 31, and the second pre-stressing assembly applies a pre-stress to the second piezoelectric vibrator 4023 in the second actuating assembly and applies the pre-stress to the side wall of the second frame 32 through the second friction head on the second piezoelectric vibrator 4023. When the second piezoelectric vibrator 4023 is deformed, it drives the second friction head to move, so that the second friction head pushes the second frame 32 to move along the second direction relative to the first frame 31 through the friction force between the second friction head and the side wall of the second frame 32. The second buffer member 4022 is arranged between the second structural member 4021 and the second piezoelectric vibrator 4023, which can offset at least part of the pre-stress change caused by the material tolerance and assembly tolerance of the first frame 31 and the second frame 32, and absorb part of the deformation of the second piezoelectric vibrator 4023. It can prevent the second actuator assembly from tilting relative to the second frame 32, and is beneficial to the vibration mode excitation of the second piezoelectric vibrator 4023. It has the effect of enhancing the driving effect of the piezoelectric motor 1 along the second direction and improving the consistency of the pre-stress provided by the second pre-stress assembly between different piezoelectric motors 1.

[0117] Furthermore, a second frame ball groove 322 is provided on the top of the second frame 32, and the movable connection between the second frame 32 and the outer shell 22 is realized by the balls in the second frame ball groove 322, and the balls in the second frame ball groove 322 and the balls in the base ball groove 212 provide support force to the first frame 31 and the second frame 32 from the upper and lower sides respectively, so that the height positions of the first frame 31 and the second frame 32 in the third direction are fixed.

[0118] More specifically, combined Figure 2 As shown, the housing 22 further includes a housing body 221 and a pressure plate 222, the housing body 221 is fixedly connected to the upper side of the pressure plate 222, a transverse spring sheet 2221 is installed on the lower surface of the pressure plate 222, and the lower surface of the transverse spring sheet 2221 abuts against the ball in the second frame ball groove 322 arranged at the top of the second frame 32, so that the transverse spring sheet 2221, as a force-applying device, always provides a pressing force to this part of the ball, so as to ensure that the second frame 32, the first frame 31 and the base 21 are assembled and flattened by the pressing force of the transverse spring sheet 2221. And the transverse spring sheet 2221 has a certain strength, so that the upper end of the second frame 32 is limited, increasing the installation strength of the housing 22 assembled to the second frame 32, and at the same time, the freedom between the housing 22 and the second frame 32 will not hinder the movement of the second frame 32 relative to the base 21, so as to increase the reliability of the piezoelectric motor 1.

[0119] In some optional embodiments, Figure 8 As shown, when the third driving mechanism 403 is improved into a driving assembly, the second frame 32 and the third frame 33 form a group of fixed parts and movable parts.

[0120] Specifically, a second frame guide groove 323 is provided on the side wall of the second frame 32, and a third frame guide groove 331 is provided on the side wall of the third frame 33. The second frame guide groove 323 and the third frame guide groove 331 are arranged opposite to each other, and the two guide grooves cooperate to form a ball channel extending in a direction parallel to the optical axis. The second frame 32 and the third frame 33 are movably connected by the balls arranged in the ball channel, so that the third frame 33 can move along the third direction relative to the second frame 32, and the connection structure is simple and easy to assemble.

[0121] It can be understood that the lens assembly 2 is arranged in the third frame 33, and the third frame 33 can move relative to the second frame 32 along the third direction, the second frame 32 can move relative to the first frame 31 along the second direction, and the first frame 31 can move relative to the base 21 along the first direction, so that the third frame 33 and the lens assembly 2 thereon have the freedom of movement in the third direction, the second direction, and the first direction relative to the base 21. In addition, the third direction is parallel to the optical axis direction, so the piezoelectric motor 1 can realize the focusing function, the first direction and the second direction are orthogonal to each other and form a plane perpendicular to the optical axis direction, so the piezoelectric motor 1 can realize the optical image stabilization function.

[0122] The end of the third structural member 4031 in the third pre-stressing assembly is connected to the outer surface of the second frame 32, and the third actuating assembly is attached to the middle part of the third structural member 4031 through the third buffer member 4032, and the third buffer member 4032 and the third actuating assembly pass through the third opening 324 on the side wall of the second frame 32. The third pre-stressing assembly applies a pre-stress to the third piezoelectric vibrator 4033 in the third actuating assembly and applies the pre-stress to the side wall of the third frame 33 through the third friction head 4034 on the third piezoelectric vibrator 4033. When the third piezoelectric vibrator 4033 is deformed, it drives the third friction head 4034 to move, so that the third friction head 4034 pushes the third frame 33 to move along the third direction relative to the second frame 32 through the friction force between the third friction head 4034 and the side wall of the third frame 33. The third buffer member 4032 is arranged between the third structural member 4031 and the third piezoelectric vibrator 4033, which can offset at least part of the prestress change caused by the material tolerance and assembly tolerance of the second frame 32 and the third frame 33, and absorb part of the deformation of the third piezoelectric vibrator 4033. It can prevent the third actuator assembly from tilting relative to the third frame 33, and is conducive to the vibration mode excitation of the third piezoelectric vibrator 4033. It has the effect of enhancing the driving effect of the piezoelectric motor 1 along the third direction and improving the consistency of the prestress provided by the third prestressing assembly between different piezoelectric motors 1.

[0123] For further reference, Fig.10 , Fig.11 , this application briefly describes the working principle of the piezoelectric vibrator 422.

[0124] For ease of description, Fig.10 The direction indicated by the arrow indicates the thickness direction of the piezoelectric vibrator 422, that is, the up-down direction, the length direction of the piezoelectric vibrator 422 is used as the front-to-back direction of the piezoelectric vibrator 422, and the width direction is used as the front-to-back direction of the piezoelectric vibrator 422.

[0125] The piezoelectric vibrator 422 has a multi-layer stacked structure. Specifically, the piezoelectric vibrator 422 is stacked in the order of ceramic layer, electrode layer, ceramic layer, electrode layer...ceramic layer, electrode layer, ceramic layer in the thickness direction. Each electrode layer is arranged between two adjacent ceramic layers, and the upper and lower halves of the piezoelectric vibrator 422 are polarized in opposite directions respectively.

[0126] There are four side electrodes on the side of the piezoelectric vibrator 422, which are respectively recorded as the first side electrode 4221, the second side electrode 4222, the third side electrode 4223, and the fourth side electrode 4224. The first side electrode 4221 and the second side electrode 4222 are arranged front to back oppositely and are both arranged on the left side of the piezoelectric vibrator 422, and the third side electrode 4223 and the fourth side electrode 4224 are arranged front to back oppositely and are both arranged on the right side of the piezoelectric vibrator 422. The first side electrode 4221 and the second side electrode 4222 are located on the left and right sides of the front of the piezoelectric vibrator 422, and are respectively suitable for receiving two electrical signals with the same frequency but different phases, such as Fig.11 The second side electrode 4222 and the fourth side electrode are located at the left and right sides behind the piezoelectric vibrator 422 and are grounded respectively.

[0127] It is easy to understand that the access of electrical signals and grounding of the side electrodes are achieved by electrical connection with the flexible circuit board 421 .

[0128] The four side electrodes extend in the thickness direction of the piezoelectric vibrator 422, and are electrically connected to the top electrode layer, the middle electrode layers, and the bottom electrode layer in sequence, so that an electric field is generated between adjacent electrode layers. Under the action of the electric field, the ceramic layer undergoes elongation or contraction deformation. Fig.11 In the figure, arrows facing each other indicate contraction, and arrows facing away indicate extension. Through the multi-layer stacked structure, the electric field formed between each two adjacent electrode layers is superimposed in the vertical direction. Therefore, the voltage required to drive the entire piezoelectric vibrator 422 to flexural vibration is reduced. The number of electrode layers and the number of ceramic layers can be designed according to the specific driving force requirements and voltage requirements that can be provided.

[0129] In order to explain the working principle of the piezoelectric vibrator 422 more clearly, based on the above settings, the piezoelectric vibrator 422 is divided into an upper left section, an upper right section, a lower left section, and a lower right section, and when the side electrode is connected to the electrical signal, four time points from t1 to t4 are intercepted for observation. The piezoelectric vibrator 422 generates the following signals at the four moments t1, t2, t3, and t4: Fig.11 In the four deformation states shown in the figure, at time t1, the upper left section and the upper right section contract, the lower left section and the lower right section extend, the piezoelectric vibrator 422 bends upward, and the friction head 423 moves downward relatively. At time t2, the upper left section and the lower right section contract, and the lower left section and the upper right section extend, so the left side of the piezoelectric vibrator 422 bends upward and the right side bends downward, and the friction head 423 moves to the upper left. At time t3 and time t4, the friction head 423 first moves upward and then moves to the lower right. The next time the input electrical signal is the same as t1, the friction head 423 moves downward to the same position as t1, and the piezoelectric vibrator 422 switches between the four deformation states, so that the friction head 423 fixed to the upper surface of the piezoelectric vibrator 422 produces an elliptical motion as shown in the figure. The friction head 423 is able to move the movable part through high frequency.

[0130] In some embodiments, in order to improve the driving performance of the piezoelectric motor 1, the piezoelectric vibrator 422 can be made of piezoelectric ceramic material or piezoelectric single crystal material. The piezoelectric vibrator 422 can be a single-layer ceramic body or a single-layer single crystal, or a multi-layer ceramic body or a multi-layer single crystal, for example, lead zirconate titanate (PZT)-based piezoelectric ceramics, potassium sodium niobate (KNN)-based piezoelectric ceramics, barium titanate (BT)-based piezoelectric ceramics, lead magnesium niobate-lead indium niobate (PMN-PT)-based piezoelectric single crystals, etc.

[0131] In some embodiments, the friction head 423 is made of wear-resistant material, for example, it can be made of various high-hardness wear-resistant ceramic materials, such as aluminum oxide, zirconium oxide, silicon carbide ceramics, or high-wear-resistant metal materials, carbon fiber materials, or composite materials of ceramics, metal particles and polymers, etc., so as to improve the wear resistance of the friction head 423, which is beneficial to increase the friction force between the moving parts and the friction head 423, that is, it is beneficial to increase the driving force, and due to the wear resistance, it is beneficial to extend the service life of the friction head 423.

[0132] In contrast, in some embodiments, reference Figure 7 As shown, the movable part is provided with a wear-resistant part 301, and the friction head 423 abuts against the wear-resistant part 301. Specifically, the wear-resistant part 301 can be a wear-resistant coating, or a friction-resistant plate assembled on the movable part by bonding, insert injection molding, etc., or an uneven outer surface of the movable part, etc., which can achieve a friction-resistant structure. The provision of the wear-resistant part 301 is conducive to improving the friction between the movable part and the friction head 423, that is, it is conducive to improving the driving force, and because of the wear resistance, it is conducive to extending the service life.

[0133] Furthermore, when the wear-resistant part 301 is set as a friction-resistant plate, it can be fixed on the movable part by bonding, fastener connection, insert injection molding, etc. to form an integrated force-bearing structure with the movable part, and referring to the material of the friction head 423, the friction-resistant plate can be made of the same or different wear-resistant material as the friction head 423.

[0134] It is understood that the present application does not impose any specific restrictions on the specific shapes of the friction head 423 and the friction-resistant plate. In a specific embodiment, the friction head 423 may be in the shape of a sphere, a hemisphere, a cuboid, a table, a cylinder, a semi-cylinder, etc., and the friction-resistant plate may be in the shape of a sheet or a block. In one example of the present application, the friction head 423 is in the shape of a cylinder. Figure 4 Vertically as shown, or as Fig.10 As shown, it is placed horizontally on the piezoelectric vibrator 422 to provide linear friction between the driving component and the movable part. The linear contact between the friction head 423 and the wear-resistant part 301 of the movable part has greater friction than the point contact method, and has better driving force and driving effect.

[0135] The number of friction heads 423 can be one or two or more. In the present embodiment, the piezoelectric vibrator 422 is in the shape of a rectangular strip, and the friction head 423 is protrudingly arranged at the center position of the side of the piezoelectric vibrator 422 facing the movable part, which can increase the unit driving stroke of the friction head 423. In another embodiment, the number of friction heads 423 is two, and the two friction heads 423 are arranged at intervals along the length direction of the piezoelectric vibrator 422, and the length direction of the piezoelectric vibrator 422 is parallel to the movement direction of the driving movable part. In the driving direction along the driving component, at least two friction heads 423 are provided on the side of the piezoelectric vibrator 422 facing the movable part, thereby increasing the driving stroke.

[0136] In some embodiments, the friction head 423 and the piezoelectric vibrator 422 can be an integrated structure or a detachable structure. The friction head 423 and the piezoelectric vibrator 422 can be fixed to the piezoelectric vibrator 422 by bonding, snapping, nesting, welding or fastener connection. The friction head 423 and the piezoelectric vibrator 422 are in surface contact to ensure the connection strength. The friction head 423 can produce obvious movement with the deformation of the piezoelectric vibrator 422.

[0137] Corresponding to the structure of the piezoelectric motor 1 provided in the present application, the present application further discloses an assembly process of the piezoelectric motor 1, which comprises the following steps:

[0138] S1. Provide a fixed member, a movable member, and a driving assembly, wherein the driving assembly includes a pre-pressing assembly 41 and an actuating assembly 42, and the pre-pressing assembly 41 includes a structural member 411 and a buffer member 412;

[0139] S2. Install the movable part into the fixed part;

[0140] S3, disposing the buffer member 412 between the structural member 411 and the actuating assembly 42 to form a combined body;

[0141] S4, extending the buffer member 412 and the actuating assembly 42 in the assembly into the opening on the fixing member, and leaving the structural member 411 outside the opening;

[0142] S5. Apply a pressure to the structural member 411 to make the structural member 411 approach the movable member, so that the actuating assembly 42 abuts against the movable member, and the buffer member 412 is squeezed and deformed by the structural member 411 and the actuating assembly 42;

[0143] S6, fixing the structural member 411 on the fixing member, and during the fixing process, continuously applying the pressure provided in step S5 to the structural member 411, and after the fixing of the structural member 411 is completed, removing the pressure;

[0144] Among them, S2 and S3 are in no particular order.

[0145] Considering that the size of the pre-stress will affect the size of the driving force of the piezoelectric actuator, although the setting of the buffer 412 can reduce the influence of the manufacturing tolerance and assembly tolerance of the material on the size of the pre-stress, there are still differences in the size of the pre-stress among the multiple piezoelectric motors 1 produced, and accordingly, there are also differences in the driving force of the piezoelectric motor 1. For the piezoelectric motors 1 manufactured in large quantities, the inconsistency of the driving force will cause a large difference in the performance of the piezoelectric motor 1. Therefore, it is necessary to further provide a method to improve the problem. To this end, the present application further improves the assembly process:

[0146] As an improvement, step S5 further includes the step of obtaining the value of the pressure applied to the structural member 411 through the pressure sensor, and adjusting the magnitude of the pressure until it is the same as the preset value. When assembling the piezoelectric motor 1, by utilizing the characteristics that the structural member 411 in the pre-stressing assembly 41 provides rigid support, and the deformation degree of the buffer member 412 can be adjusted, the pre-stress is actively calibrated and adjusted to a preset value of a fixed magnitude, so as to achieve consistency of the pre-stress in each piezoelectric motor 1.

[0147] In a specific embodiment, a device with a pressure sensor is used to apply pressure to the back of the structural member 411, and while the structural member 411 is pressed toward the fixing member to increase the current pre-pressure, the magnitude of the current pre-pressure can be measured in real time and synchronously.

[0148] It should be particularly emphasized that in the above step S6, during the process of fixing the structural member 411 on the outer side of the fixing member, it is necessary to maintain the application of pressure and keep the pressure value equal to the preset value, so that after the pressure is finally removed, the pre-pressure provided by the pre-pressure component 41 to the actuating component 42 is close to the preset value.

[0149] In some optional embodiments, in step S6, fixing the structural member 411 on the fixing member specifically includes the steps of: applying glue on the circumference of the structural member 411 and making the glue contact with the fixing member, continuously applying the pressure provided in step S5 to the structural member 411, and completing the fixing of the structural member 411 after the glue is cured, and removing the pressure.

[0150] It is understandable that if the glue is disposed between the side of the structural member 411 facing the fixing member and the outer side of the fixing member, the side of the structural member 411 facing the fixing member and the outer side of the fixing member need to be exposed before applying the glue, that is, the assembly formed in step S3 needs to be removed first, which is inconvenient to operate and may also hinder the assembly step of adjusting the preload by applying a force toward the movable member to the structural member 411. The method of coating the adhesive around the structural member 411 is convenient and efficient, and is convenient for use in actual assembly.

[0151] Furthermore, in some optional embodiments, when the adhesive is coated on the periphery of the structural member 411, the adhesive extends to the side of the structural member 411 that is not facing the fixed member. In other words, part of the adhesive is arranged in the installation direction of the actuating assembly 42, the buffer member 412, and the structural member 411. Such an arrangement enables the adhesive to have a better fixing effect, and tightly presses the structural member 411 in the direction of the fixed member and the movable member, thereby continuously and stably providing pre-pressure.

[0152] Furthermore, the glue may be UV glue, which is first coated on the circumference of the structural member 411 so that the UV glue covers at least a portion of the circumference of the structural member 411, and then cured by UV light, ie ultraviolet rays.

[0153] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A piezoelectric motor applied to a camera module, characterized in that: include: Fixings; A movable part, the movable part is movably connected to the fixed part; A driving assembly, the driving assembly includes a pre-stressing assembly and an actuating assembly, the pre-stressing assembly includes a buffer and a structural member, the structural member is connected to the fixed member, the buffer is arranged between the structural member and the actuating assembly, and is suitable for being deformed by the compression of the structural member and the actuating assembly, the pre-stressing assembly applies a pre-pressure to the actuating assembly so that the actuating assembly abuts against the movable member, so that the actuating assembly is suitable for driving the movable member to move relative to the fixed member when receiving a driving signal.

2. The piezoelectric motor according to claim 1, wherein: The structural member includes a first mounting surface facing the buffer member, the buffer member includes a second mounting surface opposite to the first mounting surface, and a third mounting surface arranged opposite to the second mounting surface, the first mounting surface is fitted with the second mounting surface, the actuator assembly includes a piezoelectric vibrator and a friction head, the piezoelectric vibrator is fitted with the third mounting surface, a side of the piezoelectric vibrator facing away from the third mounting surface is connected to the friction head, and the friction head abuts against the movable member.

3. The piezoelectric motor according to claim 1, wherein: The structural member includes a first mounting surface facing the buffer member, the buffer member includes a second mounting surface opposite to the first mounting surface, and a third mounting surface opposite to and parallel to the second mounting surface, the first mounting surface is bonded to the second mounting surface, the actuating assembly includes a flexible circuit board, a piezoelectric vibrator and a friction head, two opposite surfaces of the flexible circuit board are respectively bonded to the third mounting surface and the piezoelectric vibrator, a surface of the piezoelectric vibrator facing away from the third mounting surface is connected to the friction head, and the friction head abuts against the movable member.

4. The piezoelectric motor according to claim 1, wherein: The movable part is arranged in the fixed part, and an opening is provided on the fixed part which passes through the inner and outer sides of the fixed part. The structural part is arranged on the outer side of the fixed part, and the size of the structural part in at least one direction is larger than the size of the opening. The buffer part and the actuating assembly pass through the opening, so that the actuating assembly can abut against the movable part.

5. The piezoelectric motor according to claim 4, wherein: A gap is provided between a surface of the structural component facing the buffer component and an outer surface of the fixing component.

6. The piezoelectric motor according to any one of claims 1 to 5, characterized in that: The structural member is connected to the fixing member by an adhesive, and the adhesive covers at least a portion of a peripheral side of the structural member.

7. The piezoelectric motor according to any one of claims 1 to 5, characterized in that: The elastic coefficient of the structural member is greater than or equal to 1.2*10 ^ 5N / m; the thickness of the structural part is greater than or equal to 150μm.

8. The piezoelectric motor according to any one of claims 1 to 5, characterized in that: The elastic modulus of the buffer component is greater than or equal to 100 KPa and less than or equal to 100 MPa; the thickness of the buffer component is greater than or equal to 50 μm and less than or equal to 800 μm.

9. The piezoelectric motor according to claim 8, wherein: The buffer member is an adhesive tape, and two opposite surfaces of the buffer member are respectively bonded to the structural member and the actuating assembly.

10. The piezoelectric motor according to any one of claims 1 to 5, characterized in that: include: Base; A first frame, movably connected to the base and adapted to move relative to the base in a first direction, wherein a first driving mechanism is provided between the first frame and the base; A second frame is movably connected to the first frame and is suitable for moving relative to the first frame along a second direction, and a second driving mechanism is provided between the second frame and the first frame; a third frame, movably connected to the second frame and adapted to move relative to the second frame along a third direction, a third driving mechanism being provided between the third frame and the second frame; Wherein, at least one of the first driving mechanism, the second driving mechanism, and the third driving mechanism is the driving assembly, and when the first driving mechanism is the driving assembly, the base is a fixed part and the first frame is a movable part, when the second driving mechanism is the driving assembly, the first frame is a fixed part and the second frame is a movable part, and when the third driving mechanism is the driving assembly, the second frame is a fixed part and the third frame is a movable part.

11. A camera module, characterized in that: include: The piezoelectric motor as claimed in any one of claims 1 to 10; A lens assembly, disposed in the piezoelectric motor; The photosensitive component is arranged relative to the lens component.

12. A piezoelectric motor assembly process, characterized in that: Includes steps: S1. Provide a fixed part, a movable part, and a driving assembly, wherein the driving assembly includes a pre-pressing assembly and an actuating assembly, and the pre-pressing assembly includes a buffer part and a structural part; S2, installing the movable part into the fixed part; S3, disposing the buffer member between the structural member and the actuating assembly to form a combined body; S4, extending the buffer member and the actuating assembly in the assembly into the opening on the fixing member, and leaving the structural member outside the opening; S5, applying a pressure to the structural member to make the structural member approach the movable member, so that the actuating assembly abuts against the movable member, and the buffer member is squeezed and deformed by the structural member and the actuating assembly; S6, fixing the structural member on the fixing member, and during the fixing process, continuously applying the pressure provided in step S5 to the structural member, and after the fixing of the structural member is completed, removing the pressure; Among them, S2 and S3 are in no particular order.

13. The assembly process of a piezoelectric motor according to claim 12, wherein: Step S5 also includes the steps of: obtaining the value of the pressure applied to the structural member through a pressure sensor, and adjusting the magnitude of the pressure until it is the same as a preset value.

14. The assembly process of a piezoelectric motor according to claim 12, wherein: In step S6, fixing the structural member on the fixing member specifically includes the steps of: applying glue on the circumference of the structural member and making the glue contact with the fixing member, continuously applying the pressure provided in step S5 to the structural member, and completing the fixing of the structural member after the glue is cured, and removing the pressure.

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