A method for tunable focal zone focusing ultrasound, a method for preparing piezoelectric metasurfaces and a system

Abstract

This application discloses an adjustable focal zone focusing ultrasound method, a piezoelectric metasurface preparation method, and a system, relating to the field of electro-digital data processing. The method includes: determining key parameters of the Airy wave function based on the shape and size of the target focal region; determining the phase distribution of each piezoelectric unit based on the key parameters of the Airy wave function to form a binary phase distribution; preparing a piezoelectric metasurface with a binary phase distribution; and using the piezoelectric metasurface to achieve ultrasonic focusing. This application enables customized ultrasonic focusing according to different application requirements, improving applicability and flexibility. Simultaneously, this application enables precise control of the ultrasonic wave phase, greatly simplifying the structure of the application system, reducing manufacturing and maintenance costs, and improving the reliability and stability of the application system. This fills the technological gap of being unable to flexibly adjust FLHW and FWHW under low cost and without electrical control.

Description

Technical Field

[0001] This application relates to the field of electro-digital data processing, and in particular to an adjustable focal zone focusing ultrasound method, a piezoelectric metasurface preparation method and system. Background Technology

[0002] Ultrasonic focusing technology is widely used in medical ultrasound therapy, neuromodulation, and industrial inspection. Current mainstream solutions can be broadly categorized into two types: one uses lenses of fixed shape for physical focusing, and the other utilizes phased array transducers for electronic focusing through phase modulation. While acoustic lens solutions are low-cost and simple in structure, their focusing characteristics are fixed at the design stage, making it impossible to flexibly adjust the position, shape, or size of the focus point according to actual application needs. In other words, the shape or size of the focus point cannot be flexibly adjusted during use. Phased array transducer solutions, while possessing some dynamic adjustment capabilities and achieving adjustable focusing by controlling the phase of each array element, require a sophisticated multi-channel drive and control system. This results in a complex system structure, high cost, high energy consumption, and relatively low stability. Furthermore, the number and arrangement of array elements are limited in high-precision focusing scenarios, making them unsuitable for lightweight and customizable applications.

[0003] To achieve more flexible spatial control of ultrasound, metasurface technology has gradually entered the field of ultrasound in recent years. Metasurfaces are composed of a large number of subwavelength-scale structural units, which can precisely control the propagation direction, phase, and amplitude of sound waves at a small scale, and have functions such as wavefront shaping, beam deflection, and anomalous refraction. However, these structures usually require additional attached devices, which increases the complexity of the manufacturing process and the difficulty of system integration.

[0004] In contrast, a simpler and more efficient implementation path known to the inventors is to directly perform spatial phase encoding on the piezoelectric ceramic surface. The core idea of ​​this approach is to first uniformly polarize the entire piezoelectric ceramic, and then use silver electrodes to pattern the binary phase encoding of "whether to excite". This encoded piezoelectric metasurface structure does not require complex circuitry, is simple in structure, and is easy to mass-produce, and has been used to construct some fixed-shape ultrasonic focusing structures. This type of encoded piezoelectric metasurface, known to the inventors, can form a preset focused sound field without relying on electrical control by performing fixed phase encoding on the piezoelectric structure. However, its essential problem is that once the encoding rules are written into the structure, the degree of freedom to adjust the focus shape is lost. It can be seen that such structures can usually only generate a focus of a fixed shape, and the focus size cannot be flexibly adjusted, making it difficult to meet the needs of multi-scenario and personalized applications. Based on this, there is still a lack of systematic solutions to achieve dynamic adjustment of the shape and size of the focusing area, especially the flexible adjustment of the focus length (FLHW) and width (FWHW) under the premise of low cost and no electrical control, which remains a technological gap. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this application provides an adjustable focal zone focusing ultrasound method, a piezoelectric metasurface preparation method, and a system.

[0006] To achieve the above objectives, this application provides the following solution:

[0007] In a first aspect, this application provides an adjustable focal zone focused ultrasound method, comprising:

[0008] The key parameters of the Airy wave function are determined based on the shape and size of the target focal region;

[0009] The phase distribution of each piezoelectric unit is determined based on the key parameters of the Airy wave function;

[0010] A binary phase distribution is formed based on the phase distribution of each piezoelectric unit;

[0011] Prepare a piezoelectric metasurface having the aforementioned binary phase distribution;

[0012] Ultrasonic focusing is achieved using the aforementioned piezoelectric metasurface.

[0013] Optionally, the key parameters include the main loop radius and the scale factor.

[0014] Optionally, in the process of determining the phase distribution of each piezoelectric unit based on the key parameters of the Airy wave function, different modes of Airy waves can be generated by adjusting and setting different main loop radii and scale factors.

[0015] Optionally, the phase distribution of a single piezoelectric unit is represented as:

[0016] ;

[0017] In the formula, The phase distribution of the piezoelectric element, For the Airy wave function, The radius of the main loop. As a scale factor, For phase plane spatial coordinates, ( , () represents the initial phase plane spatial coordinates. As the attenuation factor, It is an exponential function.

[0018] Optionally, the shape of the target focal region includes a first focal shape and a second focal shape;

[0019] For the first focusing shape, , ; For the length of ultrasound waves;

[0020] Regarding the second focusing shape, , .

[0021] Optionally, the piezoelectric metasurface having the binary phase distribution is prepared by:

[0022] A piezoelectric metasurface with the aforementioned binary phase distribution is fabricated by processing piezoelectric materials using a directional polarization process.

[0023] Optionally, the dimensions of the target focal region include the length half-height full width and the width half-height full width.

[0024] Alternatively, the binary phase distribution can be represented as:

[0025] ;

[0026] In the formula, Represents binary phase distribution, This represents the phase distribution of the piezoelectric element.

[0027] Secondly, this application provides a method for preparing a piezoelectric metasurface, comprising:

[0028] Directional polarization process is used to directionally polarize piezoelectric ceramic sheets;

[0029] Silver is plated on the entire bottom surface of a directionally polarized piezoelectric ceramic sheet to obtain a silver electrode layer; the silver electrode layer is used as a common ground electrode for single-electrode excitation drive;

[0030] Based on the binary phase distribution, a silver electrode is deposited on the piezoelectric unit region with a phase of 0 on the top surface of the directionally polarized piezoelectric ceramic sheet using electroplating technology, thereby achieving a π difference in the output phase and obtaining a piezoelectric metasurface; the binary phase distribution is obtained using the adjustable focal zone focusing ultrasound method provided in this application.

[0031] Thirdly, this application provides an ultrasonic focusing application system, including a piezoelectric metasurface; the piezoelectric metasurface is prepared using the piezoelectric metasurface preparation method provided above.

[0032] According to the specific embodiments provided in this application, this application has the following technical effects:

[0033] This application provides a method for adjustable focal zone focused ultrasound, a method for preparing piezoelectric metasurfaces, and a system. Combining coded piezoelectric metasurfaces with the Airy wave principle, by determining the key parameters of the Airy wave function, ultrasonic focusing can be customized according to different application needs, improving applicability and flexibility. Furthermore, this application employs a piezoelectric metasurface designed with binary phase encoding, driven by a single-electrode excitation method, enabling precise control of the ultrasonic wave phase. This significantly simplifies the structure of the application system, reduces manufacturing and maintenance costs, and improves the reliability and stability of the application system. Thus, it fills the technological gap of being unable to flexibly adjust FLHW and FWHW under low cost and without electrical control. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic flowchart of an adjustable focus zone focused ultrasound method provided in an embodiment of this application;

[0036] Figure 2 A method for changing the main ring radius provided in one embodiment of this application and scale factor A schematic diagram of the resulting depth of focus;

[0037] Figure 3 A method for changing the main ring radius provided in one embodiment of this application and scale factor The obtained FLHW schematic diagram;

[0038] Figure 4 A method for changing the main ring radius provided in one embodiment of this application and scale factor The obtained FWHW schematic diagram;

[0039] Figure 5 A schematic diagram of the phase distribution design of a piezoelectric unit provided in an embodiment of this application;

[0040] Figure 6 This is a schematic diagram of a binary phase distribution design provided in an embodiment of this application;

[0041] Figure 7 This is a schematic diagram of the needle-like focusing result according to an embodiment of this application;

[0042] Figure 8This is a schematic diagram of the short and fat focusing result according to an embodiment of this application;

[0043] Figure 9 A schematic flowchart illustrating a method for preparing a piezoelectric metasurface according to an embodiment of this application;

[0044] Figure 10 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0046] Airy beams, as waveform structures with non-diffraction and self-acceleration properties, exhibit unique advantages in acoustic focusing. By designing a suitable phase distribution in space, sound waves can automatically form a focusing path during free propagation. However, existing research has largely focused on generating single-parameter Airy beams using static structures, and has not yet explored how to combine coded piezoelectric structures to dynamically control the focusing characteristics of Airy beams and achieve focus shape adjustment.

[0047] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] In one exemplary embodiment, this application provides an adjustable focal zone focusing ultrasound method. By encoding the binary phase of a piezoelectric metasurface and combining it with the self-focusing and self-accelerating characteristics of Airy waves, the shape and size of the ultrasound focal zone can be dynamically controlled. This allows for flexible adjustment of the FLHW and FWHW of the focal zone according to specific application requirements, thereby meeting the personalized ultrasound focusing requirements in different clinical and industrial scenarios. Figure 1 As shown, the method includes:

[0049] Step 100: Determine the key parameters of the Airy wave function based on the shape and size of the target focal region. Key parameters include the principal loop radius. and scale factor .

[0050] Step 101: Determine the phase distribution of each piezoelectric unit based on the key parameters of the Airy wave function. During this step, different main loop radii are adjusted. and scale factor This generates different modes of Airybo. For example, such as... Figures 2-4 As shown, by changing the radius of the main loop Scale factor Different FLHW and FWHW focal zones can be formed at different depths.

[0051] like Figure 5 As shown, the required phase distribution of each piezoelectric unit on the metasurface is calculated using Airy wave function parameters. ,have:

[0052] .

[0053] In the formula, The phase distribution of the piezoelectric element, For the Airy wave function, For phase plane spatial coordinates, ( , ) represents the spatial coordinates of the initial phase plane. As the attenuation factor, . It is an exponential function.

[0054] Step 102: Form a binary phase distribution based on the phase distribution of each piezoelectric unit. The resulting binary phase distribution is as follows: Figure 6 As shown. The binary phase distribution is represented as:

[0055] .

[0056] In the formula, This represents the binary phase distribution.

[0057] Step 103: Prepare a piezoelectric metasurface with a binary phase distribution. This involves using a directional polarization process to fabricate a piezoelectric material (such as PZT-4) with a predetermined binary phase distribution. piezoelectric metasurfaces, such as Figure 6 As shown.

[0058] Step 104: Use piezoelectric metasurfaces to achieve ultrasonic focusing.

[0059] In another exemplary embodiment of this application, in order to achieve dynamic and adjustable shape and size of the ultrasound focal region and meet the personalized requirements of ultrasound focusing in different application scenarios, the FLHW and FWHW in the focal region are flexibly adjusted by adjusting the key parameters of the Airy wave function. Based on this, the shape of the target focal region includes a first focusing shape and a second focusing shape, and different main ring radii are adjusted accordingly. Scale factor It can generate Airy waves in different modes, and simulate and verify these modes using conventional simulation methods. It analyzes the different focusing focal regions corresponding to different parameters, thereby enabling flexible adjustment of the focal region FLHW and FWHW to generate a focal region of the desired shape and size. For example, as... Figure 7 As shown, this is for the first focusing shape (i.e., needle-shaped focusing). , . The length of an ultrasonic wave. For example... Figure 8 As shown, this applies to the second focusing shape (i.e., short and fat focusing). , .

[0060] Based on the above description, the key point of the solution provided in this application, compared with the prior art, is as follows:

[0061] 1. This application innovatively combines coded piezoelectric metasurfaces with Airy waves. By utilizing the self-focusing and self-accelerating characteristics of Airy waves, and through the binary phase coding design of the piezoelectric metasurface, dynamic control of the shape and size of the ultrasonic focal region is achieved.

[0062] 2. This application can achieve flexible adjustment of the focal region FLHW and FWHW by precisely adjusting the key parameters of the Airy wave function to meet different application requirements.

[0063] 3. This application employs a binary phase encoding design for a piezoelectric metasurface to achieve precise control of the ultrasonic wave phase. Specifically, this application achieves precise control of the ultrasonic wave phase by designing a binary phase encoding (0 or π) on the piezoelectric metasurface, thereby generating Airy waves with predetermined characteristics and realizing dynamic control of the focal region.

[0064] 4. This application ensures the accuracy and stability of focal region control through simulation and experimental verification. Specifically, this application analyzes the shape, size, and energy distribution of the focal region under different parameters by combining numerical simulation and experimental verification, which can ensure the accuracy and stability of focal region control.

[0065] 5. This application achieves flexible control of the ultrasonic focusing area without relying on complex circuit systems, particularly enabling adjustment of the focal length and width according to actual application requirements. This application achieves an Airy wave sound field with self-focusing and self-accelerating characteristics by designing the regular polarization direction of the piezoelectric unit to form a binary phase distribution (or encoding). This structure can not only generate the traditional needle-like focusing effect but also flexibly achieve a short and wide focusing area, meeting the personalized focusing needs of different scenarios such as medical treatment, acoustic imaging, and industrial inspection.

[0066] In one exemplary embodiment, this application provides a method for preparing a piezoelectric metasurface. For example... Figure 9 As shown, the method for preparing this piezoelectric metasurface includes:

[0067] Step 200: The piezoelectric ceramic sheet is directionally polarized using a directional polarization process.

[0068] Step 201: Silver is deposited on the entire bottom surface of the directional polarized piezoelectric ceramic sheet to obtain a silver electrode layer. The silver electrode layer is used as a common ground electrode for single-electrode excitation drive.

[0069] Step 202: Based on the binary phase distribution, a silver electrode is deposited on the piezoelectric unit region with a phase of 0 on the top surface of the directionally polarized piezoelectric ceramic sheet using electroplating technology, thereby achieving a π difference in the output phase and obtaining a piezoelectric metasurface. The binary phase distribution is obtained using the adjustable focal zone focusing ultrasound method provided in this application.

[0070] Based on steps 200-202 above, for example, a PZT piezoelectric ceramic sheet that has already undergone directional polarization is selected, and a uniform layer of silver is plated on the entire bottom surface (usually the negative electrode surface) as a common ground electrode; according to the aforementioned generated binary phase distribution... On the upper surface (i.e., the top surface), silver electrodes are deposited only in the piezoelectric unit regions with a phase of 0 using electroplating technology; the piezoelectric unit regions with a phase of π are not silver-plated, so that they do not participate in the excitation, thereby achieving a π difference in the output phase. For example... Figure 5 and Figure 6 As shown, the white area indicates silver plating, and the black area indicates no silver plating.

[0071] Furthermore, all the silver layers on the upper surface are connected to a common driving signal and connected to the positive terminal, while the bottom surface serves as a common negative terminal (i.e., a common ground electrode).

[0072] In one exemplary embodiment, this application also provides an ultrasonic focusing application system. This application system includes a piezoelectric metasurface prepared using the piezoelectric metasurface preparation method described above.

[0073] In summary, the solution provided in this application has the following advantages:

[0074] (1) Achieving dynamic controllability of the ultrasound focal region to meet personalized needs: Combining coded piezoelectric metasurfaces and the Airy wave principle, by adjusting and controlling the Airy wave function parameters and converting them into electrode patterns, this application can achieve flexible adjustment of the length half-height full width (FLHW) and width half-height full width (FWHW) of the focal region without changing the structure. This allows ultrasound focusing to break through the limitations of traditional methods, retaining the simplicity of the system structure while achieving flexible adjustment of the size and shape of the focal region. It can be customized according to different application needs and is suitable for various medical and engineering application scenarios, improving the applicability and flexibility of the application system. This application does not require a complex electrical control system and has the advantages of low cost, programmability, and ease of manufacturing, which can effectively make up for the shortcomings of existing technologies in focal morphology control.

[0075] (2) Simplified system structure, reduced cost and improved reliability: This application uses a piezoelectric metasurface designed with binary phase encoding, driven by a single electrode excitation method to achieve precise control of the ultrasonic phase. Compared with traditional phased array transducers that require complex control circuits and multi-channel drive, the design method of this application greatly simplifies the system structure, reduces manufacturing and maintenance costs, and improves the reliability and stability of the system.

[0076] (3) Utilizing the self-focusing and self-accelerating characteristics of Airy waves to improve focusing efficiency and energy concentration: Airy waves have the characteristics of self-focusing and self-acceleration, which can maintain the beam shape and propagate along a predetermined trajectory during propagation. This application utilizes this characteristic to achieve efficient focusing of ultrasound waves, improve energy concentration, and help obtain more accurate results in fields such as medical diagnosis and treatment, and industrial non-destructive testing.

[0077] (4) Through simulation and experimental verification, the accuracy and stability of system performance are ensured: This application analyzes the shape, size and energy distribution of the focal region under different parameters by combining numerical simulation and experimental verification, which ensures the accuracy and stability of the focal region control, and can provide a strong guarantee for the reliability of the system in practical applications.

[0078] In addition to the tunable focal region focusing method based on coded piezoelectric metasurfaces and the Airy wave principle proposed in this application, other studies by the inventors have explored different technical approaches to achieve similar goals. One approach involves designing and 3D printing BAMs (binary planar ultrasonic lenses) to correct beam distortion caused by the skull, achieving dynamic focusing of ultrasound. Another approach introduces broadband active piezoelectric metasurfaces (APMs) to dynamically manipulate the ultrasound beam by controlling the polarization direction of the piezoelectric material. Traditional phased array transducers achieve dynamic focusing and scanning of the ultrasound beam by independently controlling the phase and amplitude of each element. While the aforementioned known solutions have their own characteristics, they have limitations in terms of system complexity, cost, energy concentration, and focal region tunability. To address these issues, this application combines coded piezoelectric metasurfaces with the Airy wave principle to dynamically control the shape and size of the ultrasound focal region. This simplifies the system structure, reduces cost, and improves focusing efficiency and energy concentration, offering significant advantages and broad application prospects.

[0079] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 10 As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores adjustable-focus focused ultrasound data. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements an adjustable-focus focused ultrasound method.

[0080] Those skilled in the art will understand that Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0081] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0082] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0083] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0084] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0085] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (RRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0086] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0087] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for focusing ultrasound with adjustable focal zone, characterized in that, include: The key parameters of the Airy wave function are determined based on the shape and size of the target focal region; The key parameters include the main loop radius and the scale factor; The shape of the target focal region includes a first focal shape and a second focal shape; The phase distribution of each piezoelectric element is determined based on the key parameters of the Airy wave function; the phase distribution of a single piezoelectric element is expressed as: ； In the formula, The phase distribution of the piezoelectric element, For the Airy wave function, The radius of the main loop. As a scale factor, For phase plane spatial coordinates, ( , () represents the initial phase plane spatial coordinates. As the attenuation factor, It is an exponential function; for the first focal shape, , ; For the length of the ultrasonic wave; for the second focusing shape. , ; A binary phase distribution is formed based on the phase distribution of each piezoelectric unit; Prepare a piezoelectric metasurface having the aforementioned binary phase distribution; Ultrasonic focusing is achieved using the aforementioned piezoelectric metasurface.

2. The adjustable focal zone focusing ultrasound method according to claim 1, characterized in that, In the process of determining the phase distribution of each piezoelectric unit based on the key parameters of the Airy wave function, different modes of Airy waves are generated by adjusting and setting different main loop radii and scale factors.

3. The adjustable focal zone focusing ultrasound method according to claim 1, characterized in that, Fabricating a piezoelectric metasurface having the aforementioned binary phase distribution includes: A piezoelectric metasurface with the aforementioned binary phase distribution is fabricated by processing piezoelectric materials using a directional polarization process.

4. The adjustable focal zone focusing ultrasound method according to claim 1, characterized in that, The dimensions of the target focal area include the length at half height and the width at half height and the full width.

5. The adjustable focal zone focusing ultrasound method according to claim 1, characterized in that, The binary phase distribution is represented as: ； In the formula, Represents binary phase distribution, This represents the phase distribution of the piezoelectric element.

6. A method for preparing a piezoelectric metasurface, characterized in that, include: Directional polarization process is used to directionally polarize piezoelectric ceramic sheets; A silver electrode layer is obtained by plating silver onto the entire bottom surface of a directionally polarized piezoelectric ceramic sheet; The silver electrode layer is used as a common ground electrode for single-electrode excitation drive; Based on the binary phase distribution, silver electrodes are deposited on the piezoelectric unit region with phase 0 on the top surface of the directionally polarized piezoelectric ceramic sheet using electroplating technology, thereby achieving a π difference in the output phase and obtaining a piezoelectric metasurface. The binary phase distribution is obtained using the adjustable focal zone focusing ultrasound method as described in any one of claims 1-5.

7. An ultrasonic focusing application system, characterized in that, It includes a piezoelectric metasurface; the piezoelectric metasurface is prepared using the piezoelectric metasurface preparation method as described in claim 6.

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