A thin-film variable-focus lens based on a threaded linear ultrasonic motor

Abstract

The present invention relates to a thin-film variable-focus lens based on a threaded linear ultrasonic motor. Aiming at the zoom system currently used for optical focusing, the present invention innovatively proposes to use an ultrasonic motor as a driving device for the optical lens. This structure greatly reduces the number of parts and the system volume, and the structure is more compact. At the same time, the overall focusing system can obtain a higher focusing speed and avoid the electromagnetic interference of traditional electromagnetic motors.

Description

Technical Field

[0001] The invention relates to a film-type variable-focus lens based on a threaded linear ultrasonic motor, belonging to the technical field of piezoelectric brakes. Background Art

[0002] A zoom system refers to a system in which the focal length can be changed within a certain range. It is a system that keeps the image distance of the object unchanged and changes the focal length of the system within a certain range. In modern life, there are more and more fields that need to use zoom systems, and with the development of science and technology, zoom systems tend to be miniaturized and integrated; however, traditional optical zoom systems require a large number of optical lenses to perform mechanical movements, which are not only costly and bulky, but also difficult to achieve miniaturization and lightweight, and their focusing accuracy and service life will continue to decrease with the use time. Zoom lenses can well make up for the shortcomings of zoom systems, complete their difficult functions, and promote the development of zoom systems in the direction of miniaturization; among them, liquid zoom lenses based on deformable materials have many advantages such as compact structure, flexible control, low cost, no mechanical wear, and easy integration. They have frequently appeared in our field of vision in recent years, but such zoom lenses require additional driving mechanisms, and the precision requirements of the driving mechanisms are also relatively high. Ordinary electromagnetic motors often have electromagnetic interference and it is difficult to meet their driving requirements. Choosing a suitable driving mechanism is a major problem in such flexible zoom lenses.

[0003] Regarding the design of its driving device, many researchers have proposed corresponding zoom lenses using driving mechanisms such as electromagnetic force, electrostatic force, and ultrasound. In 2011, Chio et al. proposed an electromagnetically driven zoom lens using two elastic films of different thicknesses, which provided an effective solution for spherical aberration correction. In 2012, Pouydesque et al. proposed a zoom lens based on electrostatic force, which used the electrostatic force between two circular electrodes to change the surface shape of the PDMS film to achieve zoom control. In 2012, Koyama et al. used ultrasound to change the surface shape of the elastic film based on the resonance principle of the material to achieve zoom control. However, the driving devices currently available on the market lack The only thing lacking is a zoom system that uses an ultrasonic motor as a driving structure. Ultrasonic motors have the characteristics of small size, light weight, compact structure, fast response speed and no electromagnetic interference. They are also very suitable for driving such flexible lenses. They use the inverse piezoelectric effect of piezoelectric ceramics to convert electrical energy into mechanical energy, which can effectively avoid the shortcomings of traditional electromagnetic motors such as electromagnetic interference and low efficiency. They can make the stator vibrate slightly through the vibration of piezoelectric materials in the ultrasonic frequency band, and under a specific excitation method, they can produce a driven elliptical motion on the stator, thereby driving the movement of the mover pressed against the stator surface, converting microscopic motion into macroscopic motion. This motion can be circular motion or linear motion.

[0004] However, the ultrasonic motor used in the zoom system needs to ensure its miniaturization, but due to the limitations of size and structure, it is often unable to obtain a large torque, which affects its efficiency to a certain extent; the current threaded motors have relatively small torques generated because the contact points between the stator and rotor are point contact or line contact; therefore, it is our expectation to develop a linear ultrasonic motor that can achieve a large torque in a limited space. Summary of the invention

[0005] The present invention provides a thin-film variable-focus lens based on a threaded linear ultrasonic motor, which makes the motor structure simpler and more compact, obtains greater driving force, and improves the efficiency of zooming.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A thin-film variable-focus lens based on a threaded linear ultrasonic motor comprises a lens frame, an optical front film, an optical rear film, an upper gasket, a lower gasket, a rigid cylindrical sheet and a fixing structure;

[0008] The surface of the lens frame is encapsulated with an optical front film, and the bottom surface thereof is encapsulated with an optical rear film. A sealed cavity is formed between the lens frame, the optical front film and the optical rear film. An optical liquid is contained in the sealed cavity. An upper gasket is installed above the optical front film, and a lower gasket is installed below the optical rear film. The thickness of the optical front film is greater than that of the optical rear film.

[0009] The fixing structure is in the shape of a hollow ring, which is installed below the frame, and its circumferential side is in contact with the optical rear film to provide support for the frame;

[0010] The rigid cylindrical sheet is adhered to the bottom surface of the optical rear film;

[0011] The motor body is installed in the hollow cavity formed by the fixed structure, and the motor body is in contact with the rigid cylindrical sheet;

[0012] As a further preferred embodiment of the present invention,

[0013] The motor body includes a stator and a rotor embedded in the stator;

[0014] The stator comprises a stator base body which is in the shape of a circular column, and an internal thread is provided on the annular inner circumference of the stator base body;

[0015] The rotor includes a rotor body, which is also in the shape of a circular cylinder. An external thread is provided on the circumferential surface of the rotor body, and the internal thread matches the external thread. The rotor body can be rotatably embedded in the stator base.

[0016] The annular upper end surface of the rotor body is in contact with the rigid cylindrical sheet;

[0017] A plurality of piezoelectric elements are respectively attached to two annular end surfaces of the stator base along the radial direction of the stator base;

[0018] An electrical signal is applied to the surface of the piezoelectric element, and its polarization direction radiates along the axial direction of the stator matrix, forming a traveling wave in the annular circumferential direction of the stator matrix. A pre-pressure is applied to the surface of the rotor body, and the rotor body rotates in the stator matrix.

[0019] As a further preferred embodiment of the present invention, eight piezoelectric elements are respectively arranged on the two annular end surfaces of the stator matrix, and four consecutive adjacent piezoelectric elements of the eight piezoelectric elements form a group, which is divided into two groups;

[0020] Applying different electrical signals to each group of piezoelectric elements;

[0021] As a further preferred embodiment of the present invention, the piezoelectric element is in the shape of an arc, and a plurality of piezoelectric elements are sequentially spliced ​​to form a circular ring that matches the end surface of the stator matrix;

[0022] The piezoelectric element is made of piezoelectric ceramics or piezoelectric single crystals;

[0023] As a further preferred embodiment of the present invention, the external thread formed on the circumferential surface of the rotor body has a triangular, trapezoidal, rectangular or arc-shaped thread profile;

[0024] As a further preferred embodiment of the present invention, the stator matrix is ​​made of metal material;

[0025] As a further preferred embodiment of the present invention, the aforementioned mirror frame is a rigid sealing ring; and both the optical front film and the optical rear film are made of PDMS optical film.

[0026] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention is aimed at the existing zoom system used for optical focusing, and innovatively proposes to use an ultrasonic motor as a driving device for an optical lens, thereby avoiding the shortcomings of the traditional zoom lens, such as complex structure, difficult control and low efficiency;

[0028] 2. The threaded linear ultrasonic motor designed for the optical focusing system of the present invention can embed lens sheets in both the stator inner cylinder and the rotor inner cylinder. This arrangement greatly reduces the number of parts of the focusing system and the volume of the system, making the structure more compact;

[0029] 3. The present invention embeds the rotor in the stator, and the stator adopts a patch structure, which makes the process simple, better realizes miniaturization and integration in the field of optical zoom, and can obtain a larger torque in a limited space;

[0030] 4. The configuration of the motor body of the present invention has a larger amplitude than that of the existing motor structure, so that the overall focusing system can obtain a higher focusing speed;

[0031] 5. The structure of the present invention can be used not only in digital focusing mechanisms, but also in smart glasses, cameras, digital cameras, digital videos and other equipment that can use focusing, such as space robots, clocks, magnetic head precision positioning, tail devices of MRI and automotive electronics, etc., and has a wide range of applicability;

[0032] 6. The present invention can better utilize the advantages of the linear ultrasonic motor such as no electromagnetic interference and rapid response, and the structure is also simpler. The zoom control accuracy can also be adjusted in time according to the travel of the linear motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0034] Figure 1 is a schematic diagram of the overall structure of a variable focus lens according to a preferred embodiment of the present invention;

[0035] Figure 2 1 is a schematic diagram of the principle of a variable focus lens according to a preferred embodiment of the present invention;

[0036] Figure 3 is a schematic diagram of the overall structure of a motor body according to a preferred embodiment of the present invention;

[0037] Figure 4 is a schematic diagram of the stator structure of a preferred embodiment of the present invention;

[0038] Figure 5 is a schematic diagram of the rotor structure of a preferred embodiment of the present invention;

[0039] Figure 6 It is a structural schematic diagram of a preferred embodiment of the present invention in which a rotor body is embedded in a stator base;

[0040] Figure 7 It is a schematic diagram of the structure of eight piezoelectric ceramic sheets located on one of the circular end faces of the stator matrix in a preferred embodiment of the present invention;

[0041] Figure 8 These are two vibration modes of the present invention, wherein 8a and 8b are two vibration modes that occur when an excitation signal of the first polarization mode and an excitation signal of the second polarization mode are applied to the stator matrix, respectively;

[0042] Fig. 9 It is a curve diagram showing that the amplitude of the motor body of the present invention directly affects the vibration of the transparent glass plate;

[0043] Fig.10 10a is a graph showing the amplitude generated by the ultrasonic motor structure of the prior art, and 10b is a graph showing the amplitude generated by the motor body of the preferred embodiment of the present application.

[0044] In the figure: 1 is a stator base, 2 is an internal thread, 3 is a rotor body, 4 is an external thread, 5 is a mirror frame, 6 is an optical front film, 7 is an optical rear film, 8 is an upper gasket, 9 is a lower gasket, 10 is a rigid cylindrical sheet, 11 is a fixed structure, and 12 is a motor body. DETAILED DESCRIPTION

[0045] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0046] In the existing focusing technology, the flexible variable focus system driven by a slightly vibrating vibrator made of deformable material has the problem of limited zoom range and difficulty in precise control of zoom accuracy; at the same time, the flexible variable focus system driven by traditional electromagnetic motor has the disadvantages of low transmission efficiency, complex structure, difficult processing, electromagnetic interference, etc. Based on the above problems, the experimenters collected information from various sources and found that the currently known information all used the structure driven by the electrostatic force principle and memory alloy materials. This structure also has the disadvantages of slow response speed, inability to focus correctly, and unclear field of view.

[0047] Based on the above, this application provides a Figure 1 The embodiment 1 shown includes a lens frame 5, an optical front film 6, an optical rear film 7, an upper gasket 8, a lower gasket 9, a rigid cylindrical sheet 10 and a fixing structure 11; the surface of the lens frame 5 is encapsulated with the optical front film 6, and the bottom surface thereof is encapsulated with the optical rear film 7; a sealed cavity is formed between the lens frame 5, the optical front film 6 and the optical rear film 7, and an optical liquid is contained in the sealed cavity; the upper gasket 8 is installed above the optical front film 6, and the lower gasket 9 is installed below the optical rear film 7, wherein the thickness of the optical front film 6 is greater than the thickness of the optical rear film 7;

[0048] The fixed structure 11 is in the shape of a hollow ring, which is installed below the frame 5, and its circumferential side is in contact with the optical back film 7 to provide support for the frame 5; the rigid cylindrical sheet 10 is adhered to the bottom surface of the optical back film 7; the motor body 12 is installed in the hollow cavity formed by the fixed structure 11, and the motor body 12 is in contact with the rigid cylindrical sheet 10.

[0049] In the preferred embodiment selected in the present application, the optical front film 6 and the optical back film 7 are both PDMS optical film, and the optical liquid contained in the sealed cavity can be glycerin, water, alcohol or other fluids, wherein the thickness of the optical front film 6 is greater than the thickness of the optical back film 7. Specifically, the thickness of the optical front film 6 is set to be 0.5 mm PDMS optical film, and the thickness of the optical back film 7 is set to be 0.2 mm PDMS optical film. At the same time, the optical front film 6 and the optical back film 7 are both flexible ring-shaped films. It should be noted that the thickness of the optical film should be as thin as possible while being able to withstand the pressure to meet the maximum deformation requirement.

[0050] The rigid cylindrical sheet 10 is a transparent glass plate.

[0051] Depend on Figure 1 It can be seen that the overall structure of this preferred embodiment 1 is compact, and the parts are reduced to the greatest extent.

[0052] Figure 2 As shown, it is a schematic diagram of the liquid zoom lens of Example 1, and the radius of the optical front film 6 is set to r t , the radius of the optical rear film 7 is r b The radius of the central piston of the transparent glass plate made of organic glass close to the optical rear film 7 is r b ; By controlling the motor body 12, the central piston is driven to move up and down, so that the points A1, A2, B1, and B2 of the optical rear film 7 are moved to A′1, A′2, B′1, and B′2 respectively, and the optical liquid in the sealed cavity is squeezed; assuming that the optical liquid in the sealed cavity is incompressible, because the volume of the sealed cavity is constant, when the liquid is squeezed, the curvature of the optical front film 6 will change;

[0053] Fig. 9 As shown, it can be clearly seen that the amplitude of the motor directly affects the vibration of the transparent glass plate, further affecting the liquid pressure of the optical liquid, thereby affecting the change in the curvature of the optical front film 6; when the design of the motor body 12 in the present application makes its radial amplitude significantly increased, the rotation speed of the motor body 12 obtains a significant change, and it pushes the movement of the transparent glass plate in the process of moving toward the transparent glass plate. The transparent glass plate squeezes the optical liquid to increase the liquid pressure in the sealed cavity, the rotation speed of the motor body 12 increases, and the deformation speed of the optical front film 6 is improved, thereby achieving the effect of rapid response of optical zoom, and thus a higher focusing speed can be obtained.

[0054] Based on Example 1, the present application proposes a threaded linear ultrasonic motor based on an in-plane mode, wherein the motor body 12 includes a stator and a rotor embedded in the stator;

[0055] The stator comprises a stator base body 1, which is in the shape of a circular column, and an internal thread 2 is provided on the annular inner circumference of the stator base body 1;

[0056] The rotor includes a rotor body 3, which is cylindrical. An external thread 4 is provided on the circumferential surface of the rotor body 3. The internal thread 2 is matched and meshed with the external thread 4, so that the rotor body 3 can be rotatably embedded in the stator base 1.

[0057] Several piezoelectric elements are pasted on the end surface of the stator matrix 1. By stimulating the piezoelectric elements, an in-plane bending traveling wave is generated in the stator matrix 1 along the circumferential direction of the ring of the stator matrix 1. The in-plane bending traveling wave directly drives the rotation of the rotor body 3 through the matching of the internal thread 2 and the external thread 4 and is converted into the axial linear motion of the rotor.

[0058] Specifically, alternating voltages of the same frequency and amplitude with a certain phase difference are applied to the piezoelectric elements respectively. Through the inverse piezoelectric effect of the piezoelectric elements, two modal responses with equal amplitudes and a phase difference of 90° in time and space can be excited at the modal frequency of the stator matrix 1. These two modal responses are superimposed on the stator matrix 1 to form a traveling wave; if a little pre-pressure is applied to the rotor body 3 at this time, through the friction between the stator matrix 1 and the rotor body 3 embedded therein, the slight vibration of the particles on the surface of the stator matrix 1 will convert the rotational motion of the rotor body 3, and the external The structure of the thread 4 matching the internal thread 2 allows the rotational motion to be converted into linear motion along the thread axis. Although many motors in the prior art also use the principle of converting the rotational motion of the rotor body 3 into linear motion, they usually use point contact and line contact. In the present application, the rotor body 3 is embedded in the stator base 1, and the internal thread 2 and the external thread 4 are matched and combined to expand the contact between the rotor body 3 and the stator base 1 to surface contact. In this way, the traveling wave formed by the superposition of modal responses in this form will inevitably produce a larger amplitude. As for the electric signal applied to the piezoelectric element, in order to make the particles on the surface of the stator matrix 1 produce an elliptical motion that drives the rotor body 3 to move, several piezoelectric elements need to be properly combined to stimulate the bending traveling waves on the stator matrix 1; in the present application, by applying different electric signals to several piezoelectric elements, standing waves can be stimulated, and the total vibration of the stator matrix 1 is based on the superposition of standing waves, and then by properly arranging the phase relationship of the electric signal applied to the piezoelectric element, it is possible to superimpose traveling waves around the stator matrix 1 in the circumferential direction; in the prior art, the piezoelectric element is generally attached to the stator tube wall, and in the present application, the piezoelectric element is attached to the annular end face of the stator matrix 1, the piezoelectric element is in an arc shape, and several piezoelectric elements are spliced ​​in sequence to form a circular ring that matches the end face of the stator matrix 1, and the polarization direction of the piezoelectric element radiates along the axial direction of the stator matrix 1. The superposition of the standing waves stimulated in this polarization direction can obtain a larger amplitude based on the structure set in the present application. Based on the above structural features, the present application is given. Figure 3 Embodiment 2 of the motor body 12 shown:

[0059] Figure 4 The stator in the embodiment is shown, which includes a stator base body 1, which is in the shape of a circular column, and an internal thread 2 is provided on the inner circumference of the circular ring of the stator base body 1. Figure 5 The figure shows a rotor in an embodiment, which includes a rotor body 3, which is cylindrical, and an external thread 4 is provided on the cylindrical circumferential outer surface of the rotor body 3, and the external thread 4 matches the internal thread 2. Figure 6 As shown, the rotor body 3 is embedded in the ring of the stator base body 1;

[0060] Eight piezoelectric elements are respectively attached to the two circular end faces of the stator substrate 1. The piezoelectric elements here are piezoelectric ceramic sheets. The eight piezoelectric ceramic sheets are evenly attached to the circular end faces of the stator substrate 1. Figure 3 As shown, the shape of the piezoelectric ceramic sheet is an arc shape, and a plurality of piezoelectric ceramic sheets are spliced ​​in sequence to form a circular ring shape matching the end face of the stator matrix 1 .

[0061] In the embodiment, the piezoelectric element is made of piezoelectric ceramics or piezoelectric single crystals;

[0062] The outer thread 4 formed on the circumferential surface of the rotor body 3 has a thread profile of a triangle, a trapezoid, a rectangle or a circular arc;

[0063] The stator base 1 is made of aluminum or other metal materials.

[0064] Figure 7 As shown, the polarization and application of electrical signals are specifically described based on the structure of the preferred embodiment. There are several polarization modes:

[0065] First, eight piezoelectric ceramic sheets located on one of the circular end faces of the stator substrate 1 are defined as: 21, 22, 23, 24, 25, 26, 27, 28, and eight piezoelectric ceramic sheets located on the other circular end face are defined as: 31, 32, 33, 34, 35, 36, 37, 38;

[0066] The first polarization mode: when the piezoelectric ceramic sheets attached to the stator substrate 1 are positively polarized along the axial direction of the stator substrate 1, the piezoelectric ceramic sheets 21, 22, 23, 24, 25, 26, 27, 28 are respectively applied with sinωt, cosωt, -sinωt, -cosωt, sinωt, cosωt, -sinωt, -cosωt signal excitations, and then an in-plane bending traveling wave is generated on this end face of the stator substrate 1, driving the rotor body 3 to rotate and move axially; similarly, applying the same signal excitations to 31, 32, 33, 34, 35, 36, 37, 38 of another annular end face of the stator substrate 1 in turn can produce a larger amplitude and a more ideal situation;

[0067] The second polarization mode: when the piezoelectric ceramic sheets 21, 22, 23, and 24 are forward polarized along the axial direction of the stator matrix 1, and the piezoelectric ceramic sheets 25, 26, 27, and 28 are reverse polarized along the axial direction of the stator matrix 1, and at the same time, a sinωt signal is applied to the piezoelectric ceramic sheets 21, 23, 25, and 27, and a cosωt signal is applied to 22, 24, 26, and 28, the rotor body 3 can also be driven to perform linear motion along the thread line.

[0068] By means of the above polarization method, the stator substrate 1 can be excited to generate Figure 8The vibration modes shown in the figure, where 8a and 8b are two vibration modes that appear when the excitation signal of the first polarization mode and the excitation signal of the second polarization mode are applied to the stator matrix 1, respectively, stimulate the modal response of the two phases of B02 with a difference of 90° in space and time, and the final vibration form of the stator is the circumferential traveling wave formed by the superposition of these two modes.

[0069] Fig.10 It can be seen that 10a is a schematic diagram of the amplitude of the ultrasonic motor structure in the prior art when it is polarized, and 10b is a schematic diagram of the amplitude of the motor body 12 in the preferred embodiment of the present application when it is polarized. It can be clearly seen from the figure that the highest amplitude generated by the motor body 12 in the preferred embodiment of the present application is significantly higher than the highest amplitude generated by the ultrasonic motor in the prior art. It can be further known that the motor body 12 in the preferred embodiment of the present application can produce a larger amplitude effect.

[0070] Based on the description of the structure, principle and implementation method of the above preferred embodiments, the present invention is specifically proposed based on the background of real-time rapid zoom of optical instruments. Combining the characteristics of liquid variable-focus lens and threaded linear ultrasonic motor, a new type of thin-film variable-focus system is proposed, and a certain feasibility analysis is proposed for this system to achieve optical zoom. Structurally, the structure is more compact and the principle is simpler. Compared with other structures for driving flexible variable-focus lenses, in addition to having a larger zoom range, the zoom distance can be controlled only by controlling the stroke of the ultrasonic motor, and the zoom speed can be controlled by controlling the motor voltage. It also avoids the electromagnetic interference and low efficiency of traditional electromagnetic motors.

[0071] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0072] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0073] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0074] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A thin film variable focus lens based on a threaded linear ultrasonic motor, characterized in that: It includes a lens frame, an optical front film, an optical rear film, an upper gasket, a lower gasket, a rigid cylindrical sheet and a fixing structure; The surface of the lens frame is encapsulated with an optical front film, and the bottom surface thereof is encapsulated with an optical rear film. A sealed cavity is formed between the lens frame, the optical front film and the optical rear film. An optical liquid is contained in the sealed cavity. An upper gasket is installed above the optical front film, and a lower gasket is installed below the optical rear film. The thickness of the optical front film is greater than that of the optical rear film. The fixing structure is in the shape of a hollow ring, which is installed below the frame, and its circumferential side is in contact with the optical rear film to provide support for the frame; The rigid cylindrical sheet is adhered to the bottom surface of the optical rear film; The motor body is installed in the hollow cavity formed by the fixed structure, and the motor body is in contact with the rigid cylindrical sheet; The motor body includes a stator and a rotor embedded in the stator; The stator comprises a stator base body which is in the shape of a circular column, and an internal thread is provided on the annular inner circumference of the stator base body; The rotor includes a rotor body, which is also in the shape of a circular cylinder. An external thread is provided on the circumferential surface of the rotor body, and the internal thread matches the external thread. The rotor body can be rotatably embedded in the stator base. The annular upper end surface of the rotor body is in contact with the rigid cylindrical sheet; A plurality of piezoelectric elements are respectively attached to two annular end surfaces of the stator base along the radial direction of the stator base; An electrical signal is applied to the surface of the piezoelectric element, and its polarization direction radiates along the axial direction of the stator matrix, forming a traveling wave in the annular circumferential direction of the stator matrix. A pre-pressure is applied to the surface of the rotor body, and the rotor body rotates in the stator matrix. Eight piezoelectric elements are respectively arranged on two annular end surfaces of the stator substrate, and four consecutive adjacent piezoelectric elements form a group, which is divided into two groups; A different electrical signal is applied to each group of piezoelectric elements.

2. The thin-film variable focus lens based on a threaded linear ultrasonic motor according to claim 1, characterized in that: The aforementioned piezoelectric element is in the shape of an arc, and a plurality of piezoelectric elements are sequentially spliced ​​to form a circular ring that matches the end surface of the stator matrix; The piezoelectric element is made of piezoelectric ceramics or piezoelectric single crystals.

3. The thin-film variable focus lens based on a threaded linear ultrasonic motor according to claim 1, characterized in that: The external thread formed on the circumferential surface of the rotor body has a tooth shape of triangle, trapezoid, rectangle or arc.

4. The thin-film variable focus lens based on a threaded linear ultrasonic motor according to claim 1, characterized in that: The stator matrix is ​​made of metal material.

5. The thin-film variable focus lens based on a threaded linear ultrasonic motor according to claim 1, characterized in that: The aforementioned mirror frame is a rigid sealing ring; both the optical front film and the optical back film are made of PDMS optical film.

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