Camera focusing mechanism and module based on ultrasonic micromotor structure

Abstract

This invention discloses a camera focusing mechanism and module based on an ultrasonic micromotor structure, belonging to the field of camera focusing mechanism design. It includes a piezoelectric thin film-driven ultrasonic micromotor, a sloping driven structure, a spring structure, and a housing with a slotted structure and a housing protrusion structure. When the stator structure of the ultrasonic micromotor generates a standing wave or traveling wave under the excitation of an external signal, the stator protrusion structure undergoes elliptical motion. This elliptical motion drives the friction layer, magnetic material layer, and sloping driven structure in the rotor structure to rotate. During rotation, the rotational direction is constrained by the cooperation of a limiting post and the slotted structure, while the sloping driven structure moves linearly along the optical axis. The housing protrusion structure and the outer edge of the rotor structure provide planar positioning. This invention achieves higher adjustment accuracy and faster response speed, making it more suitable for embedding in camera module structures of mobile phones and other terminal applications.

Description

Technical Field

[0001] This invention relates to the field of camera focusing mechanism design, and more specifically, to a camera focusing mechanism and module based on an ultrasonic micromotor structure. Background Technology

[0002] Currently, camera modules used in mobile phones, tablets, and other terminals primarily employ voice coil motors (VCMs) for driving. These motors use electromagnetic force to move the lens, changing the distance between the lens and the sensor to achieve autofocus (AF). VCMs have a relatively simple structure, mature manufacturing processes, and are already in mass production. Another technology is based on shape memory alloys (SMAs), a newer lens focusing technique that utilizes the deformation properties of shape memory alloys under temperature changes to move the lens. Alternatively, the optical properties (such as refractive index) and deformability of liquids (or soft polymers) can be utilized, and external control (such as electric fields, magnetic fields, pressure, or temperature) can be used to change the shape or position of the liquid (polymer), thereby adjusting the optical path and focal length.

[0003] The solutions using shape memory alloy wire heating or electromagnetic motor drive have the following problems: the focusing mechanism has a complex structure, large size, high noise, high requirements for driving voltage, and a large driving circuit, making it unsuitable for embedding in the camera module structure of mobile phones and other terminal applications. Furthermore, the adjustment accuracy is low and the response speed is slow. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a camera focusing mechanism and module based on an ultrasonic micromotor structure, which can achieve higher adjustment accuracy and faster response speed, and is more conducive to being embedded in the camera module structure of mobile phones and other terminal applications.

[0005] The objective of this invention is achieved through the following solution:

[0006] A camera focusing mechanism based on an ultrasonic micromotor structure includes:

[0007] The piezoelectric thin film driven ultrasonic micromotor has an inclined drive structure, a magnetic material layer and a friction layer in its rotor structure. The inclined drive structure is fixedly connected to the magnetic material layer and the friction layer. The magnetic material layer provides a rotating magnetic field when the rotor structure rotates. The stator structure has a stator protrusion structure, which contacts the friction layer and drives the rotor structure to rotate through friction.

[0008] The inclined plane is driven structure, which is integrated and fixedly connected to the mirror surface of the movable lens, and a limit post is provided on the inclined plane driven structure.

[0009] The outermost edge of the spring structure is fixed to the housing of the movable lens, and the innermost edge is fixed to the inclined plane driven structure; the inclined plane driven structure can use the elastic force of the spring structure to perform a downward movement.

[0010] The shell has a slotted structure and a shell protrusion structure.

[0011] When the stator structure generates standing waves or traveling waves under the excitation of external signals, the stator protrusion structure moves in an elliptical motion. The elliptical motion drives the friction layer, magnetic material layer and inclined surface drive structure in the rotor structure to rotate. During the rotation, the rotation direction is constrained by the cooperation of the limiting post and the slot structure. The inclined surface drive structure moves in a straight line along the optical axis. The outer edge of the shell protrusion structure and the rotor structure provides a limiting effect in the planar direction.

[0012] Furthermore, according to the requirement of friction self-locking, the inclined angle θ of the inclined driving structure is not greater than arctan(μ), and the static friction coefficient μ is the maximum static friction coefficient between the inclined driven structure and the inclined driving structure.

[0013] Furthermore, it also includes a circuit board, through which ultrasonic micro-motor drive signal lines are led out; and a magnetoresistive detection sensor is set on the circuit board, which measures the change of magnetic field during rotation, and calculates the rotation angle of the rotor structure through the sensor's sensing structure, and calculates the forward or backward distance of the movable lens through the detected rotation angle.

[0014] Furthermore, when the inclined plane drive structure rotates clockwise, the inclined plane driven structure moves upward, and the lens also moves upward. Conversely, when the inclined plane drive structure rotates counterclockwise, the lens and the inclined plane driven structure move downward by utilizing the downward pressure of the elastic force of the spring structure.

[0015] Furthermore, the shape of the housing protrusion structure includes an arc-shaped protrusion, which is disposed on the periphery of the rotor structure and makes line contact with the rotor, thus serving as a bearing limiter.

[0016] Furthermore, a mounting surface is provided on the housing, and the lower surface of the outer edge of the spring structure is fitted with the mounting surface of the movable lens housing for installation.

[0017] Furthermore, the inclined surface includes a square threaded inclined surface, a triangular or trapezoidal inclined surface.

[0018] Furthermore, the inclined plane driving structure includes a spliced ​​array structure, and the number of arrays is adjusted according to the actual design.

[0019] Furthermore, the spliced ​​array structure includes any one of a three-segment spliced ​​array structure, a two-segment spliced ​​array structure, and a four-segment spliced ​​array structure.

[0020] A camera module includes a camera focusing mechanism based on an ultrasonic micromotor structure as described in any of the preceding claims.

[0021] The beneficial effects of this invention include:

[0022] This invention achieves higher adjustment precision and faster response speed, making it more suitable for embedding in camera module structures of mobile phones and other terminal applications. Specifically, it proposes a new overall structure based on ultrasonic micro-motor drive. The rotor structure uses a threaded inclined surface drive structure to convert rotational motion into linear motion, effectively acting as a focus adjustment mechanism. Furthermore, the inclined surface drive structure possesses self-locking capability, meaning the lens structure maintains its displacement even when the ultrasonic motor is powered off and stops driving. The invention also improves the integrated design of the rotor structure, which consists of three main parts: an inclined surface drive structure, a magnetic material layer structure, and a friction layer structure. The inclined surface structure drives the inclined surface up and down, while the magnetic material provides a rotational magnetic field for angle detection and preload on both the stator and rotor. The friction layer works in conjunction with the stator to achieve optimal frictional drive efficiency and wear resistance. Finally, the invention innovates the design of the driven inclined surface structure. Its upper part has an elastic structure that acts as a spring, providing restoring or preload force. Side limiting posts engage with slots in the outer shell to restrict the degree of freedom of rotation, ensuring that it can only rotate under the drive of the ultrasonic micro-motor. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the first structure according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the second structure according to an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the third structure according to an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the fourth structure according to an embodiment of the present invention.

[0028] In the diagram, 200 is the fixed lens section, 20 is the fixed frame, 21 is the lens, 30 is the photosensitive chip unit, and 31 is the photosensitive chip unit substrate; 100 is the movable lens section, 40 is the mirror surface, and 1 is the moving part of the movable lens.

[0029] 16-Lens substrate structure, 17-Circuit board, 171-Magnetoresistive detection sensor, 18-Stator structure, 181-Stator protrusion structure;

[0030] 1345 - Rotor structure, 13 - Inclined drive structure, 14 - Magnetic material layer, 15 - Friction layer;

[0031] 11-Spring structure, 12-Inclined surface driven structure, 120-Limiting post;

[0032] 10-Shell, 101-Groove structure, 102-Shell protrusion structure, 103-Shell mounting surface. Detailed Implementation

[0033] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0034] To address the problems described in the background, the applicant of this application, after further creative thinking, proposed a camera focusing mechanism based on a piezoelectric ultrasonic motor, in addition to the driving methods described in the background. Further research revealed that a piezoelectric ultrasonic motor (USM) is a novel type of motor that utilizes ultrasonic vibration energy for driving. Unlike traditional electromagnetic motors, the USM (Unstable Ultrasonic Motor) has no magnetic poles or windings and does not rely on electromagnetic interactions to transfer energy. Instead, it utilizes the inverse piezoelectric effect of piezoelectric ceramics (when certain materials are deformed by external forces in a certain direction, polarization occurs inside them, and opposite charges appear on their two opposing surfaces. When the external force is removed, they return to an uncharged state; this phenomenon is called the direct piezoelectric effect. When the direction of the force changes, the polarity of the charges also changes. Conversely, when an electric field is applied in the polarization direction of the material, these materials will also deform; when the electric field is removed, the deformation of the material disappears; this phenomenon is called the inverse piezoelectric effect) to convert electrical energy into mechanical energy of ultrasonic vibration (mechanical vibration frequency 20kHz). Then, through the contact and friction between the stator and rotor, the alternating vibration is converted into unidirectional rotation or linear motion of the rotor, realizing the conversion of mechanical vibration energy into rotor kinetic energy.

[0035] The driving principle of ultrasonic motors reveals their advantages, including high positioning accuracy, high torque at low speeds, no need for a reduction gear, direct drive capability, self-locking upon power failure, simple structure, high degree of freedom in motor shape design, low noise, and no electromagnetic interference. Due to these unique characteristics compared to electromagnetic motors, ultrasonic motors have specific applications and scenarios. In 1987, Canon officially applied a ring-shaped ultrasonic motor based on bulk PZT to the autofocus system of cameras. In previous camera autofocus structures, electromagnetic motors were installed in the rear body of the camera and drove the lens through a series of transmission mechanisms, including a reduction gear. Due to the influence of transmission system backlash and inertia, the response time was typically over 100ms, resulting in low positional accuracy. The hollow structure of the ring-shaped ultrasonic motor perfectly suits the optical requirements of the lens, being installed on the outer periphery for direct lens drive without intermediate transmission. This results in faster response (generally within 10ms), improved positioning accuracy, and simultaneously meets the requirements of good controllability and low noise in cameras.

[0036] With advancements in technology, particularly piezoelectric thin films and microfabrication techniques, ultrasonic micromotors based on PZT piezoelectric thin films and microfabrication have become capable of being embedded in camera modules for mobile phones and other terminal applications, while simultaneously meeting application requirements such as power consumption and size. However, technical challenges remain, including further reducing driving voltage and power consumption, improving response speed, and enhancing adjustment accuracy.

[0037] This invention specifically provides a technical solution for a camera focusing mechanism and corresponding module based on an ultrasonic micromotor structure. In the focusing mechanism, a piezoelectric ultrasonic micromotor, fabricated using piezoelectric thin film and microfabrication technology, is used for driving. While bulk piezoelectric ultrasonic motors require driving voltages of up to hundreds of volts, the micro-ultrasonic motor and driving circuit driven by the piezoelectric thin film in this invention are smaller in size and require lower driving voltages, making them more suitable for embedding in camera module structures of mobile phones and other terminal applications. Based on this, a new integrated focusing mechanism structure based on ultrasonic micromotor driving is proposed, and corresponding improvements are made to the integrated structure and driving structure of the rotor of the piezoelectric ultrasonic micromotor in the focusing mechanism.

[0038] In a preferred embodiment of the present invention, a camera focusing mechanism based on an ultrasonic micromotor structure is specifically provided. This improves the overall focusing structure driven by the ultrasonic micromotor, converting rotational motion into linear motion by driving the lens structure through the inclined surface drive structure of the rotor structure, thus achieving a focusing function. Specifically, it includes:

[0039] The piezoelectric thin film driven ultrasonic micromotor has an inclined drive structure, a magnetic material layer and a friction layer in its rotor structure. The inclined drive structure is fixedly connected to the magnetic material layer and the friction layer. The magnetic material layer provides a rotating magnetic field when the rotor structure rotates. The stator structure has a stator protrusion structure, which contacts the friction layer and drives the rotor structure to rotate through friction.

[0040] The inclined plane is driven structure, which is integrated and fixedly connected to the mirror surface of the movable lens, and a limit post is provided on the inclined plane driven structure.

[0041] The outermost edge of the spring structure is fixed to the housing of the movable lens, and the innermost edge is fixed to the inclined plane driven structure; the inclined plane driven structure can use the elastic force of the spring structure to perform a downward movement.

[0042] The shell has a slotted structure and a shell protrusion structure.

[0043] When the stator structure generates standing waves or traveling waves under the excitation of external signals, the stator protrusion structure moves in an elliptical motion. The elliptical motion drives the friction layer, magnetic material layer and inclined surface drive structure in the rotor structure to rotate. During the rotation, the rotation direction is constrained by the cooperation of the limiting post and the slot structure. The inclined surface drive structure moves in a straight line along the optical axis. The outer edge of the shell protrusion structure and the rotor structure provides a limiting effect in the planar direction.

[0044] In this embodiment, the integrated design of the rotor structure mainly consists of three parts: an inclined plane drive structure, a magnetic material structure, and a friction layer structure. The inclined plane structure drives the inclined plane to move up and down, the magnetic material provides a rotational magnetic field, which can be used for angle detection, and the friction layer cooperates with the stator to achieve optimal friction drive efficiency and wear resistance. The outer periphery of the rotor structure has a shell protrusion structure that can make line contact with the rotor structure, serving as a bearing limiter. In the design of the inclined plane driven structure, its upper part has an elastic structure that acts as a spring, providing restoring force or preload. The side limiting posts cooperate with the slot structure of the outer shell to restrict the degree of freedom of rotation, so that it can only perform rotational motion under the drive of the ultrasonic micromotor.

[0045] In a further embodiment, based on the above embodiments, the driving form of the inclined plane structure is made to have self-locking capability. According to the requirement of friction self-locking, the inclined plane angle θ of the inclined plane driving structure is not greater than arctan(μ), and the static friction coefficient μ is the maximum static friction coefficient between the inclined plane driven structure and the inclined plane driving structure.

[0046] In other alternative implementations, based on the above embodiments, a circuit board is also included, through which an ultrasonic micromotor drive signal line is led out; and a magnetoresistive detection sensor is provided on the circuit board, through which the magnetic field change during rotation is measured, and the rotation angle of the rotor structure is calculated by back-calculating through the sensor's sensing structure, and the distance of the movable lens forward or backward is calculated by back-calculating through the detected rotation angle.

[0047] In other alternative implementations, based on the above embodiments, when the inclined plane driving structure rotates clockwise, the inclined plane driven structure moves upward, and the lens also moves upward. Conversely, when the inclined plane driving structure rotates counterclockwise, the lens and the inclined plane driven structure move downward by utilizing the downward pressure of the elastic force of the spring structure.

[0048] In other alternative implementations, based on the above embodiments, the shape of the housing protrusion structure can be designed as an arc-shaped protrusion. The arc-shaped protrusion is disposed on the periphery of the rotor structure and makes line contact with the rotor, thus playing the role of bearing limiting.

[0049] In other alternative embodiments, based on the above embodiments, a mounting surface is also provided on the housing, and the lower surface of the outer edge of the spring structure is fitted with the mounting surface of the housing of the movable lens.

[0050] In other alternative implementations, based on the above embodiments, the inclined surface can be designed as any one of a square threaded inclined surface, a triangular or trapezoidal inclined surface.

[0051] In other alternative implementations, based on the above embodiments, the inclined plane driving structure can be designed as a spliced ​​array structure, and the number of arrays can be adjusted according to the actual design.

[0052] In other alternative implementations, based on the above embodiments, the spliced ​​array structure can be designed as any one of a three-segment spliced ​​array structure, a two-segment spliced ​​array structure, and a four-segment spliced ​​array structure.

[0053] In a preferred embodiment of the present invention, a camera module is specifically provided, which is provided with a camera focusing mechanism based on an ultrasonic micromotor structure as described in any of the above embodiments, and related electronic devices utilizing the camera module.

[0054] The technical solutions of the embodiments of the present invention will be further described below with reference to the accompanying drawings and more detailed technical specifications:

[0055] like Figure 1 , Figure 2 and Figure 3As shown, a camera focusing mechanism based on an ultrasonic micromotor structure is first provided, including a fixed lens portion 200 and a movable lens portion 100. The fixed lens portion 200 (composed of a fixing frame 20 and a lens 21) is placed on a photosensitive chip unit 30 and its substrate (photosensitive chip unit substrate 31). The movable lens portion 100 is fixed on the fixed lens portion 200. Reference numeral 1 indicates the moving part of the movable lens. The movable lens portion 100 further includes a mirror surface 40, a housing 10, a lens base structure 16, a circuit board 17, a stator structure 18, a rotor structure 1345, a spring structure 11, and a sloped driven structure 12. The sloped driven structure 12 is integrated and fixed with the mirror surface 40 of the movable lens. When the ultrasonic micromotor rotates, the mirror surface 40 is driven to move up and down along the optical axis, achieving automatic focusing. The outermost edge of the spring structure 11 is fixed to the housing 10 of the movable lens, and the innermost edge is fixed to the sloped driven structure 12. The fixing method includes, but is not limited to, bonding and welding.

[0056] The integrated design of the rotor structure 1345 includes an inclined drive structure 13, a magnetic material layer 14, and a friction layer 15. The inclined drive structure 13 is fixed to the magnetic material layer 14 and the friction layer 15 in the rotor structure 1345 of the ultrasonic micromotor. A stator protrusion structure 181 is provided on the stator structure 18. The stator protrusion structure 181 of the stator structure 18 contacts the friction layer 15 of the rotor structure 1345 of the ultrasonic micromotor, driving the rotor structure to rotate through friction. When the stator structure 18 of the ultrasonic micromotor is exposed to an external sinusoidal wave signal... Driven by excitation, standing waves or traveling waves are generated, causing the stator protrusion structure 181 to perform elliptical motion. This elliptical motion drives the friction layer 15, magnetic material layer 14, and inclined plane drive structure 13 in the rotor structure 1345 to rotate. When the inclined plane drive structure 13 rotates clockwise, the inclined plane driven structure 12 moves upward, and the mirror 40 also moves upward. Conversely, when the inclined plane drive structure 13 rotates counterclockwise, the downward pressure of the elastic force of the spring structure 11 causes the mirror 40 and the inclined plane driven structure 12 to move downward. The inclined plane drive structure drives the inclined plane to move up and down, and the magnet provides the rotating magnetic field, which serves as an angle detection function. The friction layer and the stator structure work together to achieve optimal friction drive efficiency and wear resistance.

[0057] The circuit board 17 is an FPC flexible circuit board for leading out ultrasonic micromotor drive signal lines. A magnetoresistive detection sensor 171 is provided on the circuit board 17. When the stator structure of the ultrasonic micromotor drives the friction layer 15, magnetic material layer 14 and inclined drive structure 13 in the rotor structure to rotate, the magnetic material layer 14 can be set in the shape of a magnet ring. Since the magnet ring is bonded or welded to the inclined drive structure 13 and friction layer 15, when the rotor structure 1345 rotates, the magnetic field generated by the magnet in the magnetic material layer 14 changes. The change in magnetic field can be detected by the magnetoresistive sensor 171. The rotation angle of the rotor can be calculated by the sensing structure of the sensor. The distance of the movable lens forward or backward can be calculated by the detected rotation angle.

[0058] The base structure 16 of the movable lens is mounted on the top of the fixed frame 20, the fixed frame 20 is mounted on the base 31, and the photosensitive chip unit 30 is mounted in the center of the lens.

[0059] The movable lens is the core of this application, and its working principle is further explained in detail here: A limiting post 120 is provided on the inclined driven structure 12, and a slot structure 101 and a housing protrusion structure 102 are provided on the housing 10 of the movable lens. When the stator structure 18 of the ultrasonic micromotor vibrates and is excited, it drives the rotor structure 1345 to rotate, and the inclined surface of the inclined driven structure 13 drives the inclined driven structure 12. At this time, because the limiting post 120 of the inclined driven structure 12 cooperates with the slot structure 101 of the housing 10 of the movable lens, the degree of freedom of rotation is strictly constrained. Therefore, under the rotational drive of the rotor structure 1345, the inclined driven structure 12 can only perform linear motion along the optical axis. When the rotor structure 1345 rotates, the housing protrusion structure 102 on the housing 10 of the movable lens and the outer edge of the rotor structure 1345 play a limiting role in the planar direction, so that it only has the degree of freedom in the rotational direction. The housing protrusion structure 102 is designed as an arc-shaped protrusion, which is located on the periphery of the rotor and can make line contact with the rotor, thus serving as a bearing limit. The lower surface of the outer edge of the spring structure 11 is fitted and installed with the housing mounting surface 103 of the movable lens housing 10.

[0060] The slope angle of the inclined plane drive structure 13 is one of the key points, and a balance needs to be found between self-locking and efficiency. Given the self-locking requirements of this application, the slope angle cannot be designed to be too large. Figure 4In the example shown, the inclined plane angle is the angle between the threaded inclined plane and the plane perpendicular to the axis. However, it should be noted that the inclined plane can be not only a square threaded inclined plane, but also a triangular or trapezoidal inclined plane according to the requirements. The angle of the inclined plane is determined by the friction coefficient between the inclined plane driven structure 12 and the inclined plane driving structure 13 according to the stroke of the linear motion. According to the requirement of friction self-locking, the inclined plane angle θ is not greater than arctan(μ), and the static friction coefficient μ is the maximum static friction coefficient between the inclined plane driven structure 12 and the inclined plane driving structure 13. Figure 4 The inclined structure in the embodiment is a three-segment splicing array. The number of arrays can also be adjusted according to the actual design, such as 2 or 4.

[0061] In summary, compared to the focusing mechanism driven by a voice coil motor, the technical solution of this invention, based on a piezoelectric ultrasonic micromotor, can achieve low speed and high torque, can be directly driven without a reduction mechanism, has self-locking upon power failure, and maintains lower energy consumption. The motor's structural shape design is beneficial to the focusing structure, offering advantages in size and making it easier to achieve thinner and smaller designs, while also exhibiting low noise in the ultrasonic frequency band. Compared to solutions using bulk piezoelectric materials, the ultrasonic micromotor using a piezoelectric thin film in this invention is thinner and has a lower driving voltage. While bulk piezoelectric ultrasonic motors can have driving voltages up to hundreds of volts, the micro-ultrasonic motor and driving circuit driven by the piezoelectric thin film are smaller, making them more suitable for embedding in camera modules of mobile phones and other terminal applications. The technical solution of this invention uses a rotor-structured inclined drive structure to drive the lens structure, converting rotational motion into linear motion, thus achieving a focusing function. Moreover, the inclined drive structure has self-locking capability. Compared to solutions using shape memory alloy wire heating or electromagnetic motors, which have slow response speeds on the order of tens or hundreds of milliseconds, the piezoelectric response speed of the technical solution of this invention is faster, and combined with angle detection, it can achieve higher closed-loop control adjustment accuracy.

[0062] The above description is merely the technical principles and preferred embodiments used in this invention. Those skilled in the art will understand that this invention is not limited to the specific embodiments described herein. Various obvious changes, adjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of this invention. Therefore, although the invention has been described in detail through the above embodiments, this invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the principles and concept of this invention, and the scope of this invention is determined by the scope of the appended claims.

Claims

1. A camera focusing mechanism based on an ultrasonic micromotor structure, characterized in that, include: The piezoelectric thin film driven ultrasonic micromotor has an inclined drive structure, a magnetic material layer and a friction layer in its rotor structure. The inclined drive structure is fixedly connected to the magnetic material layer and the friction layer. The magnetic material layer provides a rotating magnetic field when the rotor structure rotates. The stator structure has a stator protrusion structure, which contacts the friction layer and drives the rotor structure to rotate through friction. The inclined plane is driven structure, which is integrated and fixedly connected to the mirror surface of the movable lens, and a limit post is provided on the inclined plane driven structure. The outermost edge of the spring structure is fixed to the housing of the movable lens, and the innermost edge is fixed to the inclined plane driven structure; the inclined plane driven structure can use the elastic force of the spring structure to perform a downward movement. The shell has a slotted structure and a shell protrusion structure. When the stator structure generates standing waves or traveling waves under the excitation and drive of external signals, the stator protrusion structure makes elliptical motion, and the elliptical motion drives the friction layer, magnetic material layer and inclined surface drive structure in the rotor structure to rotate. During rotation, the rotational direction is constrained by the cooperation of the limiting post and the slot structure. The inclined plane is driven to make a linear motion along the optical axis. The outer edge of the shell protrusion structure and the rotor structure plays a limiting role in the plane direction perpendicular to the optical axis.

2. The camera focusing mechanism based on an ultrasonic micromotor structure according to claim 1, characterized in that, According to the requirements of friction self-locking, the slope angle θ of the inclined plane driving structure is not greater than arctan(μ), and the static friction coefficient μ is the maximum static friction coefficient between the inclined plane driven structure and the inclined plane driving structure.

3. The camera focusing mechanism based on an ultrasonic micromotor structure according to claim 1, characterized in that, It also includes a circuit board, from which ultrasonic micro-motor drive signal lines are led out; and a magnetoresistive detection sensor is set on the circuit board, which measures the change of magnetic field during rotation, and calculates the rotation angle of the rotor structure through the sensor's sensing structure, and calculates the forward or backward distance of the movable lens through the detected rotation angle.

4. The camera focusing mechanism based on an ultrasonic micromotor structure according to claim 1, characterized in that, When the inclined plane drive structure rotates clockwise, the inclined plane driven structure moves upward, and the lens also moves upward. Conversely, when the inclined plane drive structure rotates counterclockwise, the lens and the inclined plane driven structure move downward due to the downward pressure of the elastic force of the spring structure.

5. The camera focusing mechanism based on an ultrasonic micromotor structure according to claim 1, characterized in that, The shape of the housing protrusion structure includes an arc-shaped protrusion, which is located on the periphery of the rotor structure and makes line contact with the rotor, thus serving as a bearing limiter.

6. The camera focusing mechanism based on an ultrasonic micromotor structure according to claim 1, characterized in that, The housing is also provided with a mounting surface, and the lower surface of the outer edge of the spring structure is fitted with the mounting surface of the movable lens housing for installation.

7. The camera focusing mechanism based on an ultrasonic micromotor structure according to claim 1, characterized in that, The inclined surface includes a square threaded inclined surface, a triangular or trapezoidal inclined surface.

8. The camera focusing mechanism based on an ultrasonic micromotor structure according to claim 1, characterized in that, The inclined plane driving structure includes a spliced ​​array structure, and the number of arrays is adjusted according to the actual design.

9. The camera focusing mechanism based on an ultrasonic micromotor structure according to claim 8, characterized in that, The spliced ​​array structure includes any one of a three-segment spliced ​​array structure, a two-segment spliced ​​array structure, and a four-segment spliced ​​array structure.

10. A camera module, characterized in that, The camera focusing mechanism based on an ultrasonic micromotor structure, as described in any one of claims 1 to 9.

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