Transducer for balanced heating and preparation method

Abstract

Disclosed in the present invention are a transducer for balanced heating and a preparation method. The transducer comprises a piezoelectric material layer. The piezoelectric material layer is cylindrical. A through hole is formed in the center of the piezoelectric material layer. A support structure is arranged on an inner side of the through hole. The piezoelectric material layer is connected to an external device by means of the support structure. An electrically conductive layer is arranged on a surface of the piezoelectric material layer. An isolation strip is arranged on the electrically conductive layer. The electrically conductive layer is divided into a positive electrode portion and a negative electrode portion by means of the isolation strip. After being electrified, the transducer generates balanced vibration and emits sound waves in a radial direction. The human tissue absorbs the sound waves and then has an elevated temperature, thereby achieving balanced heating. The apparatus is connected to the external device by means of the support structure to avoid the generation of more solder points at the ablation site, and has a good annular heating effect; excitation signals completely flow through the entire piezoelectric material layer, so that the generated energy is more uniform, enabling 360° simultaneous ablation in blood vessels and thus achieving a better ablation effect. Additionally, the assembling and manufacturing process is optimized, thereby improving the vibration performance of the transducer.

Description

A balanced heating transducer and preparation method thereof Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a transducer with balanced heating and a preparation method thereof. Background Art

[0002] Hypertension is a common clinical disease. Renal artery ultrasound ablation is an ablation system based on the piezoelectric effect. When stimulated by an adaptive frequency signal, the ultrasonic transducer generates vibrations based on the piezoelectric effect and emits a 360° ultrasonic sound field in the radial direction of the transducer. The ultrasonic waves will be absorbed by external tissues, generating heat and achieving 360° ablation.

[0003] In clinical practice, existing ultrasonic transducers are generally directly welded with wires, resulting in thicker welds at the tail end of the ultrasonic transducer. When the ultrasonic transducer is working, it is easy to cause uneven heating of the transducer. In addition, the design of ordinary flip-over electrodes causes the transducer to have about 20-30% of the area along the entire axial direction where the piezoelectric effect fails to occur, the ablation length is insufficient, and the ablation efficiency is low. It is necessary to adjust the delivery position of the ultrasonic transducer multiple times, so that no lesions are generated or the ablated part is subjected to multiple or long-term ablations, which increases the clinical risk of patients.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a transducer with balanced heating and a preparation method.

[0006] In order to achieve the above-mentioned object, the present invention adopts the following technical solution: a transducer with balanced heating, comprising: a piezoelectric material layer;

[0007] The piezoelectric material layer is cylindrical with a through hole in the middle. A support structure is provided inside the through hole, and the piezoelectric material layer is connected to an external device through the support structure.

[0008] Conductive layers are provided on both sides of the piezoelectric material layer, and an isolation belt is provided on the piezoelectric material layer. The isolation belt divides the conductive layer into a positive electrode part and a negative electrode part. When energized, the transducer generates balanced vibrations and emits sound waves in the radial direction. After being absorbed by human tissue, the temperature rises, thereby achieving balanced heating.

[0009] As a further description of the above technical solution: the support structure is a support column.

[0010] Also included is a transducer with balanced heating, comprising:

[0011] a piezoelectric material layer;

[0012] The piezoelectric material layer is cylindrical and has a through hole in the middle;

[0013] Conductive layers are provided on both sides of the piezoelectric material layer, and an isolation belt is provided on the piezoelectric material layer. The isolation belt divides the conductive layer into a positive electrode part and a negative electrode part. When energized, the transducer generates balanced vibrations and emits sound waves in the radial direction. After being absorbed by human tissue, the temperature rises, thereby achieving balanced heating.

[0014] As a further description of the above technical solution: the positive electrode portion is located on the outer diameter surface of the piezoelectric material layer, and the negative electrode portion is located on the inner diameter surface of the piezoelectric material layer, forming a first structure or a second structure.

[0015] As a further description of the above technical solution: in the first structure, the negative electrode portion is located on the inner diameter surface of the piezoelectric material layer and does not exceed the end surface of the piezoelectric material layer;

[0016] In the second structure, the negative electrode portion is located on the inner diameter surface of the piezoelectric material layer and one end surface of the piezoelectric material layer, and extends toward the outer diameter surface.

[0017] As a further description of the above technical solution: the ratio of the thickness to the diameter of the piezoelectric material layer is between 2-10, and the thickness of the piezoelectric material layer is 0.5-1.5 mm.

[0018] As a further description of the above technical solution: the thickness of the conductive layer is 10 μm-200 μm.

[0019] As a further description of the above technical solution: the support structure is a spiral support structure or a C-shaped support structure.

[0020] As a further description of the above technical solution: in the first structural state, the support structure is a spiral support structure.

[0021] As a further description of the above technical solution: in the second structural state, the support structure is a C-shaped support structure, and the opening size is not greater than 1 / 6 of the circumference.

[0022] As a further description of the above technical solution: the outer diameter of the supporting structure of the first structural transducer is slightly larger than the inner diameter of the piezoelectric material layer, has an interference fit with the inner wall of the piezoelectric material layer, is elastically clamped on the inner side of the piezoelectric material layer, and the radial overlapping part with the piezoelectric material layer does not exceed 1 / 10 of the total length of the piezoelectric material layer.

[0023] As a further description of the above technical solution: the support structure is located on the outer side of the piezoelectric material layer and is welded to the wire to serve as the first stage of the transducer.

[0024] As a further description of the above technical solution: the welding point is located at a 180° direction of the C-shaped opening position of the support structure.

[0025] Also included is a method for preparing a transducer, which is applicable to the transducer described in any one of the above technical solutions, comprising:

[0026] S1: The piezoelectric material layer is formed by electric field polarization, gas polarization or thermal polarization and then sintered. The outer side of the piezoelectric material layer is pretreated to improve surface adhesion;

[0027] S2: Apply a polymer layer, adhesive glue or wrapping tape to the inside of the isolation tape;

[0028] S3: depositing a conductive layer on the outer side of the piezoelectric material layer by PVD or CVD, removing the conductive layer at the position of the isolation band after the conductive layer is formed, and setting the isolation band at the position of the piezoelectric material layer so that the isolation band divides the conductive layer outside the piezoelectric material layer into a positive electrode portion and a negative electrode portion;

[0029] S4: A support structure is installed inside the piezoelectric material layer, and the piezoelectric material layer is connected to an external device through the support structure.

[0030] As a further description of the above technical solution: the material of the piezoelectric material layer is a ceramic or polymer composite chip.

[0031] As a further description of the above technical solution: the positive electrode portion and the negative electrode portion of the conductive layer are made of the same material.

[0032] As a further description of the above technical solution: the material of the support structure is nickel titanium, stainless steel, or titanium alloy.

[0033] The above technical solution has the following advantages or beneficial effects:

[0034] 1. The support structure is connected to the external equipment, which solves the difficulty of welding wires in the transducer cavity. The piezoelectric effect can occur in the entire axial direction of the transducer. While having a good heating length, the annular heating effect is good. The excitation signal flows completely through the entire piezoelectric material layer, and the energy generated is more uniform, which can achieve better ablation effect. It can ablate 360 ​​degrees simultaneously in the blood vessel, with low processing difficulty and low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a structural schematic diagram of a transducer proposed in the present invention;

[0036] FIG2 is a second structural diagram of the transducer proposed by the present invention;

[0037] FIG3 is a schematic diagram of a wavy isolation zone of the first structure of the transducer in the present invention;

[0038] FIG4 is a schematic diagram of a sinusoidal isolation band of a first structure of a transducer in the present invention;

[0039] FIG5 is a schematic diagram of a supporting structure of a first structure of a transducer in the present invention;

[0040] FIG6 is a schematic diagram of a C-shaped support column of a second structure of a transducer in the present invention;

[0041] FIG7 is a schematic diagram of welding a C-shaped support column of the second structure of the transducer in the present invention;

[0042] FIG8 is a perspective view of a C-shaped support for a transducer in a second structure of the transducer according to the present invention;

[0043] FIG9 is a schematic diagram showing a comparison of the acoustic power in the four directions of transducers with different overlapping sizes in the present invention;

[0044] FIG10 is a schematic diagram showing a comparison of the acoustic power in the four directions of the transducer with different opening sizes of the support structure according to the present invention;

[0045] FIG11 is a flow chart of a method for preparing a transducer according to the present invention.

[0046] Legend:

[0047] 1. Piezoelectric material layer; 2. Support structure; 3. Conductive layer; 31. Positive electrode; 32. Negative electrode; 4. Isolation zone; 5. Sound power in the four directions of the structure with an overlapping size of 1 / 20 of the total length of the transducer; 6. Sound power in the four directions of the structure with an overlapping size of 1 / 5 of the total length of the transducer; 7. Sound power in the four directions of the structure with an opening size of 1 / 10 of the circumference of the support structure 2; 8. Sound power in the four directions of the structure with an opening size of 1 / 5 of the circumference. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] An embodiment provided by the present invention: a transducer with balanced heating, comprising: a piezoelectric material layer 1; the piezoelectric material layer 1 is cylindrical, with a through hole in the middle, a support structure 2 is provided on the inside of the through hole, and the piezoelectric material layer 1 is connected to an external device through the support structure 2; a conductive layer 3 is provided on the surface of the piezoelectric material layer 1, and an isolation belt 4 is provided on the conductive layer 3, and the conductive layer 3 is divided into a positive electrode portion 31 and a negative electrode portion 32 by the isolation belt 4. When energized, the transducer generates balanced vibration and emits sound waves in the radial direction. After being absorbed by human tissue, it heats up to achieve balanced heating.

[0050] In this embodiment, the piezoelectric material layer 1 is cylindrical with a through hole in the middle. It can also be set to a tubular structure, a square tubular structure, a rugby-shaped structure, etc. as needed. A conductive layer 3 is prepared on the inside and outside of the piezoelectric material layer 1. The piezoelectric material layer 1 is controlled to vibrate through the conductive layer 3 to achieve electro-acoustic conversion. A support structure 2 is provided on the inside of the piezoelectric material layer 1, which can be connected to external equipment, such as a polymer tube, a metal tube, etc., to ensure that the transducer is fixed while not restricting the radial vibration of the transducer, especially the radial inward vibration, so as to better achieve balanced heating of the transducer.

[0051] The isolation strip 4 is disposed outside the piezoelectric material layer 1, dividing the conductive layer 3 into a positive electrode portion 31 and a negative electrode portion 32, ensuring that the excitation signal transmitted via the wire passes through the entire conductive layer 3. The isolation strip 4 can generally be composed of a polymer material such as polytetrafluoroethylene or a ceramic material. Preferably, the isolation strip 4 can be formed by applying glue or a pre-set polymer layer to the piezoelectric material layer 1 before the conductive layer 3 is attached, thereby preventing the conductive layer 3 from adhering to the isolation strip 4. At the same time, the insulating properties of the ceramic itself are used to isolate the positive and negative electrodes.

[0052] In this embodiment, the isolation strip 4 can be manufactured into a rectangular, semicircular or sinusoidal surround design according to different transducer structures.

[0053] The positive electrode portion 31 is located on the outer diameter surface of the piezoelectric material layer 1 , and the negative electrode portion 32 is located on the inner diameter surface of the piezoelectric material layer 1 , forming a first structure or a second structure.

[0054] In this embodiment, the conductive layer 3 is located on the outer surface of the piezoelectric material layer 1 and is separated by an isolation band 4. The positive electrode portion 31 and the negative electrode portion 32 are connected to different wires. When performing ablation operations, they are respectively connected to the input voltage to receive excitation signals to control the piezoelectric material layer 1 to vibrate.

[0055] In the first structure, the negative electrode portion 32 is located on the inner diameter surface of the piezoelectric material layer 1 and one end surface of the piezoelectric material layer 1 , and extends toward the outer diameter surface.

[0056] The second structure is that the negative electrode portion 32 is located on the inner diameter surface of the piezoelectric material layer 1 and does not exceed the end surface of the piezoelectric material layer 1;

[0057] In this embodiment, the transducer has two different structures by preparing the negative electrode portion 32. When the negative electrode portion 32 is located on the inner diameter surface of the piezoelectric material layer 1 and the positive electrode portion 31 is located on the outer diameter surface of the piezoelectric material layer 1, there is no contact between the positive electrode portion 31 and the negative electrode portion 32. The conductive layer 3 is not provided on the end surfaces of the piezoelectric material layer 1, and isolation is achieved through the material properties of the piezoelectric material layer 1 itself.

[0058] 5 , when the negative electrode portion 32 extends through the cylindrical bottom surface of the piezoelectric material layer 1 to a portion of the outer diameter surface, the positive electrode portion 31 and the negative electrode portion 32 can be separated by providing an isolation tape 4 for connecting the negative electrode portion 32 to the wire, thereby forming the first structure of the transducer in this embodiment;

[0059] 7 , the negative electrode portion 32 is located on the inner diameter surface of the piezoelectric material layer 1 and does not exceed the end surface of the piezoelectric material layer 1 ; the C-shaped support structure 2 is elastically clamped to the inner wall of the transducer, and the exposed portion of the support structure is used to connect the wire to the negative electrode portion of the transducer, forming the second structure of the transducer in this embodiment;

[0060] The material of the support structure 2 is nickel titanium, stainless steel, or titanium alloy.

[0061] In the embodiment of the first structure, the support structure 2 is made of nickel titanium, which has better elasticity, less impact on the vibration of the transducer, and is more conducive to the balanced heating of the transducer. The support structure 2 is preferably a spiral support column, which can provide internal support for the transducer and facilitate the fixation of the transducer. The wall of the spiral support column can be perforated to ensure the supporting force while reducing the weight of the support column, which is conducive to the uniform heating of the transducer. The spiral support column can be perforated according to the requirements of the transducer to reduce the contact area between the interior and the transducer and improve the heating efficiency of the transducer.

[0062] In the embodiment of the second structure, the support structure 2 is made of nickel titanium, which has better elasticity, less impact on the vibration of the transducer, and is more conducive to the balanced heating of the transducer. The outer diameter of the C-shaped support column of the support structure 2 is designed to be slightly larger than the inner diameter of the negative electrode part 32 on the inner side of the piezoelectric material layer 1. The outer diameter can be reduced under the action of external force, so that after the outer diameter of the support structure 2 is reduced, it can be inserted into the through hole of the piezoelectric material layer 1 and fixed to the inner wall of the piezoelectric material layer 1 based on its own elastic rebound.

[0063] The C-shaped support structure 2 needs to control the overlap size with the inner wall of the transducer in the radial direction. Preferably, the overlap size is less than 1 / 10 of the total length of the transducer.

[0064] Figure 9 compares the circumferential acoustic power (5) for a structure with an overlap of 1 / 20 the total transducer length and the circumferential acoustic power (6) for a structure with an overlap of 1 / 5 the total transducer length. Acoustic power represents the circumferential heating of the transducer. The results show that a smaller overlap results in more uniform circumferential heating and higher acoustic power.

[0065] Figure 7 shows the specific connection between the C-shaped support structure 2 and the transducer. The exposed portion is directly welded to the wire, forming the first stage of the transducer. The solder joint is located 180° from the opening of the support column C to ensure uniform heating of the transducer. The other pole is secured to the outer diameter of the transducer using conductive adhesive or welding.

[0066] The opening size of the C-shaped support structure 2 needs to be smaller than 1 / 6 of the circumference, that is, the opening angle is smaller than 30°, to ensure that the potential of the negative electrode portion 32 of the conductive layer 3 is more uniform.

[0067] Figure 10 compares the acoustic power (7) around the structure when the opening size of support structure 2 is 1 / 10 of the circumference, and the acoustic power (8) around the structure when the opening size is 1 / 5 of the circumference. Acoustic power represents the circumferential heating of the transducer. The results show that a smaller opening size in support structure 2 results in more uniform heating around the structure.

[0068] In all embodiments, the ratio of the thickness to the diameter of the piezoelectric material layer 1 is between 2 and 10, and the thickness of the piezoelectric material layer 1 is 0.5-1.5 mm. In this embodiment, the thickness of the piezoelectric material layer is between 0.5-1.5 mm, and the diameter of the piezoelectric material layer is 1-4 mm. When the ratio of the diameter to the thickness is between 3 and 6, the heating efficiency is higher.

[0069] The thickness of the conductive layer 3 is 10 μm-200 μm. In this embodiment, while having better conductivity, it does not affect the vibration effect of the piezoelectric material layer, thereby improving energy conversion efficiency. Furthermore, the thickness of the conductive layer 3 is 20 μm-50 μm. The conductive material layer of this size has better conductivity. An excessively thick conductive material layer will affect the vibration effect of the piezoelectric material layer and reduce energy conversion efficiency.

[0070] The support structure 2 is a support column. In this embodiment, the support column is a spiral support column or a C-shaped support column. While ensuring radial support and fixation, it reduces the contact area with the inner side of the piezoelectric material layer 1. At the same time, a more precise size design is used to maintain the original resonance point of the transducer as much as possible, thereby better maintaining the transducer's better electro-acoustic conversion efficiency and other parameters.

[0071] 11 , the present invention further provides an embodiment of a method for preparing a transducer, which is applicable to any transducer in the above technical solutions, comprising:

[0072] S1: The piezoelectric material layer 1 is sintered after being polarized by an electric field, gas or heat, and the outer side of the piezoelectric material layer 1 is pretreated to improve surface adhesion;

[0073] S2: Apply a polymer layer, adhesive glue or wrapping tape to the inner side of the isolation tape 4;

[0074] S3: depositing a conductive layer 3 on the outer side of the piezoelectric material layer 1 by PVD or CVD. After the conductive layer 3 is formed, the conductive layer 3 at the position of the isolation band 4 is removed, and the isolation band 4 is placed on the piezoelectric material layer 1 so that the isolation band 4 divides the conductive layer 3 outside the piezoelectric material layer 1 into a positive electrode portion 31 and a negative electrode portion 32;

[0075] S4: A support structure 2 is installed inside the piezoelectric material layer 1 and is connected to an external device through the support structure 2.

[0076] In this embodiment, the piezoelectric material layer 1 is a hollow structure made by polarizing a ceramic / polymer composite chip and then sintering it. After the piezoelectric material layer 1 is sintered, the surface is pre-treated by electrochemical, physical sandblasting, plasma treatment, etc. to improve the surface roughness, thereby increasing the adhesion effect with the conductive layer 3. Preferably, plasma treatment, etc. are used to improve the surface roughness while reducing damage to the piezoelectric material layer 1, preventing large fluctuations in the resonance and anti-resonance frequencies of the piezoelectric material layer 1. Plasma treatment can increase the adhesion and conductivity effects with the conductive layer 3.

[0077] After the pretreatment is completed, the setting position of the isolation belt 4 is determined as needed, and the polymer layer, adhesive glue or wrapping tape is applied to the two side end faces or outer diameter of the piezoelectric material layer 1 to set the isolation belt 4. The conductive layer 3 is deposited on the outside of the piezoelectric material layer 1 by PVD (physical vapor deposition) or CVD (chemical vapor deposition), preferably by PVD (physical vapor deposition). After the deposition is completed, the part with the isolation belt 4 is raised upward, and the excess conductive layer 3 is removed by etching, so that the conductive layer 3 is divided into a positive electrode part 31 and a negative electrode part 32, which are isolated by the isolation belt 4. The excitation signal can be completely transmitted to the piezoelectric material layer 1 through the conductive layer 3.

[0078] After depositing and preparing the conductive layer 3, the support structure 2 is arranged on the inner side of the piezoelectric material layer 1, and is matched with the negative electrode part 32 with a small gap. Spot welding is performed between the support structure 2 and the external device. The welding position is 180° in the direction of the opening position of the C-shaped support structure 2. Compared with the existing direct ring welding of the conductive layer 3 and the external device, the welding area is smaller and the heat generation is more uniform.

[0079] The material of the piezoelectric material layer 1 is a ceramic or polymer composite wafer.

[0080] In this embodiment, the piezoelectric material layer 1 is made of an insulating material, which can prevent the positive electrode portion 31 and the negative electrode portion 32 from being connected when the conductive layer 3 is prepared.

[0081] The positive electrode portion 31 and the negative electrode portion 32 of the conductive layer 3 are made of the same material.

[0082] The conductive layer 3 is usually made of a metal material with good electrical conductivity and strong oxidation resistance. In this embodiment, gold is preferably used because of its good electrical conductivity and oxidation resistance.

[0083] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A transducer with balanced heating, characterized in that: include: A piezoelectric material layer (1); The piezoelectric material layer (1) is cylindrical, with a through hole in the middle, a support structure (2) is arranged inside the through hole, and the piezoelectric material layer (1) is connected to an external device through the support structure (2); Conductive layers (3) are arranged on both sides of the piezoelectric material layer (1), and an isolation belt (4) is arranged on the piezoelectric material layer (1). The isolation belt (4) divides the conductive layer (3) into a positive electrode portion (31) and a negative electrode portion (32). When energized, the transducer generates balanced vibration and emits sound waves in a radial direction. After being absorbed by human tissue, the temperature rises, thereby achieving balanced heating. The supporting structure (2) is a supporting column; The support structure is a spiral support structure or a C-shaped support structure; The positive electrode portion (31) is located on the outer diameter surface of the piezoelectric material layer (1), and the negative electrode portion (32) is located on the inner diameter surface of the piezoelectric material layer (1), forming a first structural state or a second structural state; The first structural state is that the negative electrode portion (32) is located on the inner diameter surface of the piezoelectric material layer (1) and does not exceed the end surface of the piezoelectric material layer (1); In the first structural state, the support structure (2) is a spiral support structure; The second structural state is that the negative electrode portion (32) is located on the inner diameter surface of the piezoelectric material layer (1) and the end surface of one side of the piezoelectric material layer (1), and extends toward the outer diameter surface; In the second structural state, the support structure (2) is a C-shaped support structure, and the opening size is no greater than 1 / 6 of the circumference; When the transducer has a first structural state, the outer diameter of its supporting structure (2) is slightly larger than the inner diameter of the piezoelectric material layer (1), and is interference fit with the inner wall of the piezoelectric material layer (1), and is elastically snapped onto the inner side of the piezoelectric material layer (1), and the radial overlap with the piezoelectric material layer (1) does not exceed 1 / 10 of the total length of the piezoelectric material layer (1).

2. The transducer according to claim 1, characterized in that: The ratio of the thickness to the diameter of the piezoelectric material layer (1) is between 2 and 10, and the thickness of the piezoelectric material layer (1) is between 0.5 and 1.5 mm.

3. The transducer according to claim 1, characterized in that: The thickness of the conductive layer (3) is 10 μm-200 μm.

4. The transducer according to claim 1, characterized in that: The support structure (2) is located on the outer side of the piezoelectric material layer (1) and is welded to a wire to serve as the first stage of the transducer.

5. The transducer according to claim 1, characterized in that: The welding spot is located at a 180° direction of the C-shaped opening of the support structure (2).

6. A method for preparing a transducer, characterized in that: The preparation method is applicable to the transducer according to any one of claims 1 to 5, comprising: S1: The piezoelectric material layer (1) is formed by sintering after being polarized by electric field, gas or heat, and the outer side of the piezoelectric material layer (1) is pretreated to improve the surface adhesion; S2: Applying a polymer layer, bonding glue or wrapping tape on the inner side of the isolation tape (4); S3: depositing a conductive layer (3) on the outside of the piezoelectric material layer (1) by PVD or CVD, after the conductive layer (3) is formed, removing the conductive layer (3) at the position of the isolation band (4), and setting the isolation band (4) at the piezoelectric material layer (1), so that the isolation band (4) divides the conductive layer (3) on the outside of the piezoelectric material layer (1) into a positive electrode portion (31) and a negative electrode portion (32); S4: A support structure (2) is installed inside the piezoelectric material layer (1), and is connected to an external device via the support structure (2).

7. The preparation method according to claim 6, characterized in that: The material of the piezoelectric material layer (1) is a ceramic or polymer composite wafer.

8. The preparation method according to claim 6, characterized in that: The positive electrode portion (31) and the negative electrode portion (32) of the conductive layer (3) are made of the same material.

9. The preparation method according to claim 6, characterized in that: The material of the support structure (2) is nickel titanium, stainless steel, or titanium alloy.

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