A two-dimensional composite vibration ultrasonic transducer and its design method

Abstract

The present invention relates to an ultrasonic transducer with two-dimensional composite vibration and a design method thereof. The size of a piezoelectric element in the ultrasonic transducer can satisfy the following conditions: when the piezoelectric element is excited, the resonant frequencies of the piezoelectric element in the thickness direction and the width direction can be coupled to the same frequency to generate two-dimensional composite vibrations in the thickness direction and the width direction. The two-dimensional composite vibration can allow the ultrasonic wave emitted by the ultrasonic transducer to propagate in multiple directions, thereby achieving a wider coverage range and more efficient energy transfer, and can significantly enhance the effect of ultrasound-assisted thrombolytic therapy. Through the design method, only initial performance parameters and target performance parameters need to be obtained to obtain the corresponding piezoelectric element size. Under this size, the piezoelectric element can realize two-dimensional composite vibrations in the thickness direction and the width direction, and can avoid its coupling effect in the length direction, thereby avoiding unnecessary consumption of energy output by the ultrasonic transducer.

Description

Technical Field

[0001] The present invention relates to the technical field of interventional medical devices, and in particular to a two-dimensional composite vibration ultrasonic transducer and a design method thereof. Background Art

[0002] Thrombotic diseases are common and frequently occurring diseases in clinic. In my country, there are millions of cases of thrombi every year. Thrombi are composed of insoluble fibrin, deposited platelets, accumulated white blood cells and trapped red blood cells. After thrombi are formed in blood vessels, they will block the normal flow of blood, leading to ischemia of local tissues or organs, and even necrosis.

[0003] There are currently many methods for the treatment of venous thromboembolism, and ultrasound-assisted thrombolysis is one of them. In ultrasound-assisted thrombolysis, the ultrasonic guide core is guided to the location of the embolism in the vascular lumen, radiating ultrasound into the thrombus, and at the same time injecting thrombolytic drugs into the thrombus. The mechanical vibration and cavitation effect of ultrasound are used to loosen the tight fibrin structure in the thrombus, promoting the delivery of thrombolytic drugs into the thrombus, thereby improving the thrombolytic efficiency of the drug.

[0004] In the prior art, the ultrasonic guide core can only emit ultrasonic waves in two directions, so there will be an uneven distribution of ultrasonic energy. In some directions, due to insufficient ultrasonic energy, the thrombolysis effect is not ideal. Based on this, how to design an ultrasonic transducer that can generate two-dimensional composite vibrations has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] The invention discloses a two-dimensional composite vibration ultrasonic transducer and a design method thereof, which are used to solve the problems existing in the prior art.

[0006] In a first aspect, an embodiment of the present invention provides a two-dimensional composite vibration ultrasonic transducer, comprising at least one ultrasonic transmitting unit, the ultrasonic transmitting unit comprising a first electrode wire, a second electrode wire and a piezoelectric element;

[0007] The first electrode wire is arranged at the central axis, the two piezoelectric elements are electrically connected to the two axial sides of the first electrode wire respectively, and the two piezoelectric elements are configured as rectangular blocks of the same size, and the two second electrode wires are electrically connected to the two piezoelectric elements respectively and extend in the axial direction;

[0008] The size of the piezoelectric element satisfies that when the piezoelectric element is excited, the resonant frequencies of the piezoelectric element in the thickness direction and the width direction can be coupled to the same frequency, thereby generating two-dimensional composite vibrations in the thickness direction and the width direction.

[0009] As a preferred technical solution, the size of the piezoelectric element further satisfies: no coupling effect occurs in the length direction of the piezoelectric element.

[0010] As a preferred technical solution, the ratio of the width to the thickness of the piezoelectric element is negatively correlated with the thickness frequency constant of the piezoelectric element.

[0011] As a preferred technical solution, the thickness frequency constant is negatively correlated with the material density of the piezoelectric element.

[0012] As a preferred technical solution, the ratio of the width to the thickness of the piezoelectric element is configured to be 0.3-3, and the length of the piezoelectric element is configured to be more than 3 times the thickness and / or width.

[0013] As a preferred technical solution, the thickness direction of the piezoelectric element is the polarization direction, the length direction of the piezoelectric element is the direction parallel to the axis of the first electrode wire, and the width direction of the piezoelectric element is another direction perpendicular to the thickness direction and the length direction.

[0014] In a second aspect, an embodiment of the present invention provides a method for designing a two-dimensional composite vibration ultrasonic transducer, the method for designing a two-dimensional composite vibration ultrasonic transducer as described in any one of the above items, comprising:

[0015] Obtaining initial performance parameters and target performance parameters of the piezoelectric element;

[0016] The calculation models of the apparent compliance constants of the piezoelectric element in the width direction and the thickness direction are constructed respectively;

[0017] Construct a resonant frequency model of a piezoelectric element when a two-dimensional fundamental frequency resonance occurs;

[0018] According to the apparent compliance constant calculation model and the resonance frequency model, a correlation model between the width-to-thickness ratio and the thickness frequency constant of the piezoelectric element is constructed;

[0019] Based on the initial performance parameters and the target performance parameters, the size of the piezoelectric element is determined through the correlation model.

[0020] As a preferred technical solution, the initial performance parameters include the material density of the piezoelectric element, multiple groups of elastic compliance constants, and stress components of the piezoelectric element in the length direction, width direction, and thickness direction. The multiple groups of elastic compliance constants include: a first elastic compliance constant of the piezoelectric element in which the polarization direction is the length direction and the vibration direction is also the length direction, a second elastic compliance constant of the piezoelectric element in which the polarization direction is the length direction and the vibration direction is the width direction, a third elastic compliance constant of the piezoelectric element in which the polarization direction is the length direction and the vibration direction is the thickness direction, and a fourth elastic compliance constant of the piezoelectric element in which the polarization direction is the thickness direction and the vibration direction is also the thickness direction;

[0021] Target performance parameters include a target resonant frequency and a target aspect ratio of the piezoelectric element.

[0022] As a preferred technical solution, in the step of respectively constructing the calculation model of the apparent compliance constant of the piezoelectric element in the width direction and the thickness direction, it also specifically includes:

[0023] Based on the piezoelectric equation, the strain component calculation models of the piezoelectric element in the length direction, width direction and thickness direction are constructed respectively;

[0024] Calculate the Poisson's ratio of the piezoelectric element in multiple directions;

[0025] Construct a calculation model for the coupling coefficient of piezoelectric elements vibrating in the thickness and width directions;

[0026] Based on the strain component calculation model, Poisson's ratio and coupling coefficient calculation model, the strain component calculation models of the piezoelectric element in the width direction and thickness direction are constructed respectively.

[0027] As a preferred technical solution, in the step of constructing a resonant frequency model of a piezoelectric element when a two-dimensional fundamental frequency resonance occurs, the step includes:

[0028] A first resonant frequency model and a second resonant frequency model are constructed respectively, the first resonant frequency model is associated with the width of the piezoelectric element, and the second resonant frequency model is associated with the thickness of the piezoelectric element.

[0029] As a preferred technical solution, the step of determining the size of the piezoelectric element based on the initial performance parameters and the associated model includes:

[0030] Obtaining a set of coupling coefficients of the piezoelectric element vibrating in the thickness direction and the width direction;

[0031] Based on the correlation model, the values ​​of several width-to-thickness ratios and thickness frequency constants are determined;

[0032] Based on the target performance parameters, the size of the piezoelectric element is determined.

[0033] In a third aspect, an embodiment of the present invention provides an electronic device, including:

[0034] one or more processors;

[0035] A memory for storing one or more programs;

[0036] When the one or more programs are executed by the one or more processors, the one or more processors implement the method for designing a two-dimensional composite vibration ultrasonic transducer as described in any one of the above items.

[0037] In a fourth aspect, an embodiment of the present invention provides a readable storage medium, on which is stored a design program for an ultrasonic transducer with two-dimensional composite vibrations. When the design program is executed by a processor, it is capable of implementing a design method for an ultrasonic transducer with two-dimensional composite vibrations as described in any one of the above items.

[0038] Compared with the prior art, the technical solution adopted by the present invention can achieve the following beneficial effects:

[0039] In one embodiment, the present invention provides an ultrasonic transducer with two-dimensional composite vibrations, in which the size of the piezoelectric element can satisfy the following requirements: when the piezoelectric element is excited, the resonant frequencies of the piezoelectric element in the thickness direction and the width direction can be coupled to the same frequency to generate two-dimensional composite vibrations in the thickness direction and the width direction. This two-dimensional composite vibration can allow the ultrasonic waves emitted by the ultrasonic transducer to propagate in multiple directions, thereby achieving a wider coverage range and more efficient energy transfer. Especially when applied to ultrasound-assisted thrombolysis, it can significantly enhance the treatment effect and shorten the operation time.

[0040] In another embodiment of the present invention, a design method for the above-mentioned two-dimensional composite vibration ultrasonic transducer is provided. Based on this design method, complicated experimental operations are no longer required, and the design steps are simplified. Only the initial performance parameters and the target performance parameters need to be obtained to obtain the corresponding piezoelectric element size. Under this size, the piezoelectric element can realize two-dimensional composite vibration in the thickness direction and the width direction, and can avoid its coupling effect in the length direction, thereby avoiding unnecessary consumption of the energy of the ultrasonic transducer sound output. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0042] Figure 1 This is a schematic structural diagram of a two-dimensional composite vibration ultrasonic transducer disclosed in Example 1 of the present invention;

[0043] Figure 2 It is a schematic structural diagram of the ultrasonic guide core disclosed in Example 1 of the present invention;

[0044] Figure 3 This is a schematic structural diagram of the ultrasonic transducer group disclosed in Example 1 of the present invention;

[0045] Figure 4 This is a curve diagram showing the relationship between the thickness frequency constant and the width-to-thickness ratio disclosed in Example 2 of the present invention.

[0046] Description of reference numerals:

[0047] Piezoelectric element 11, first electrode wire 12, second electrode wire 13, ultrasonic transducer group 14, Luer connector 15, power connector 16. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0049] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0050] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] refer to Figure 1 In an embodiment of the present invention, a two-dimensional composite vibration ultrasonic transducer is provided, which is preferably used in ultrasound-assisted thrombolysis. During treatment, ultrasonic energy can be radiated from the inside of the thrombus to the surrounding area, so that the thrombolytic drug can be more evenly distributed inside the thrombus to accelerate the dissolution of the thrombus.

[0053] In a preferred embodiment, the two-dimensional composite vibration ultrasonic transducer includes at least one ultrasonic transmitting unit, such as Figure 1 The ultrasonic transmitting unit includes a first electrode wire 12, a second electrode wire 13 and a piezoelectric element 11, wherein the first electrode wire 12 is preferably configured as a negative electrode wire and is arranged at the central axis of the ultrasonic transmitting unit, and a piezoelectric element 11 is electrically connected to both sides of the first electrode wire 12, and the piezoelectric elements 11 correspondingly arranged on the left and right are configured as rectangular blocks of the same size, and a second electrode wire 13 is electrically connected to the outer side surfaces of the two piezoelectric elements 11, and the second electrode wire 13 is preferably configured as a positive electrode wire and extends axially.

[0054] When an alternating voltage is applied to the first electrode wire 12 and the second electrode wire 13, the piezoelectric element 11 is excited to generate mechanical vibration, thereby emitting ultrasonic waves outward; in some embodiments, the piezoelectric element 11 can be made of piezoelectric ceramics, polyvinylidene fluoride (PVDF) or single crystal piezoelectric materials, and piezoelectric ceramic materials are further preferably used.

[0055] Preferably, the piezoelectric element 11 has three directions, the polarization direction of the piezoelectric element 11 is defined as its thickness direction, the direction parallel to the axis of the first electrode wire 12 is defined as its length direction, and another direction perpendicular to the thickness direction and the length direction is defined as its width direction.

[0056] In a preferred embodiment, the size of the piezoelectric element 11 satisfies that: when the piezoelectric element 11 is excited by an alternating voltage, the resonant frequencies of the piezoelectric element 11 in the thickness direction and the width direction can be coupled to the same frequency, generating two-dimensional composite vibrations in the thickness direction and the width direction. This two-dimensional composite vibration enables the ultrasonic waves emitted by the ultrasonic transducer to propagate in multiple directions, thereby achieving a wider coverage range and more efficient energy transfer, especially when applied to ultrasound-assisted thrombolysis, which can significantly enhance the treatment effect and shorten the operation time.

[0057] Specifically, when the piezoelectric element 11 is excited by an alternating voltage, it vibrates at a natural frequency, which is the resonant frequency. At the resonant frequency, the piezoelectric element 11 can generate vibrations with maximum amplitude. In the present embodiment, the piezoelectric element 11 can generate resonant frequencies in both its thickness direction and width direction when excited, and couple to the same frequency, thereby generating vibrations in both the thickness direction and the width direction and emitting ultrasonic waves. Since the vibration in the width direction and the vibration in the thickness direction are not in the same plane, it is called "two-dimensional composite vibration".

[0058] In a preferred embodiment, since the length direction of the piezoelectric element 11 is the transmission direction of the ultrasonic transducer in the human body, the vibration of the piezoelectric element 11 in the length direction basically has no therapeutic effect and also consumes the energy output by the ultrasonic transducer. In order to convert the electrical energy into vibrations in the thickness and width directions as much as possible, the size of the piezoelectric element 11 further satisfies the following requirements: the length direction of the piezoelectric element 11 does not produce a coupling effect.

[0059] In a preferred embodiment, the ratio of the width to the thickness of the piezoelectric element 11 is negatively correlated with its thickness frequency constant. Specifically, the thickness frequency constant is the product of the resonant frequency of the piezoelectric element 11 in the thickness direction and its thickness. The thickness frequency constant is negatively correlated with the material density of the piezoelectric element 11. Therefore, further, the width-to-thickness ratio of the piezoelectric element 11 is negatively correlated with the material density of the piezoelectric element 11.

[0060] In a preferred embodiment, based on the above design concept, the width-to-thickness ratio of the piezoelectric element 11 is configured to be 0.3-3, the length of the piezoelectric element 11 is configured to be more than 3 times its thickness and / or width, and the frequency is 20KHz-10MHz; specifically, after determining the width-to-thickness ratio and thickness-frequency constant of the piezoelectric element 11, the thickness and width values ​​of the piezoelectric element 11 can be further determined based on the relationship between the two.

[0061] Furthermore, this embodiment also provides an ultrasonic guide core, which includes a plurality of axially electrically connected two-dimensional composite vibration ultrasonic transducers to form an ultrasonic transducer group 14, such as Figure 2 and Figure 3 The ultrasonic transducer group 14 is coated with an encapsulating glue on its periphery, and a Luer connector 15 and a power connector 16 are further provided at its proximal end. Preferably, a temperature sensor can be further provided between the ultrasonic transducer group 14 and the encapsulating glue. The specific structure and setting position of the temperature sensor can refer to any embodiment disclosed in the prior art and are not specifically limited here.

[0062] Furthermore, this embodiment further provides an ultrasonic thrombolytic device, including the above-mentioned ultrasonic guide core, and a thrombolytic catheter is provided outside the ultrasonic guide core for delivering the ultrasonic guide core in the body. In this embodiment, the structure and size of the thrombolytic catheter are no longer specifically limited, and technical personnel in this field can freely choose according to actual needs.

[0063] Example 2

[0064] In an embodiment of the present invention, a two-dimensional composite vibration ultrasonic transducer design method is provided, which is used to design the two-dimensional composite vibration ultrasonic transducer in the above-mentioned embodiment 1. The technical features recorded in the above-mentioned embodiment 1 are naturally inherited in this embodiment and will not be repeated.

[0065] Preferably, the above design method includes:

[0066] S210 , obtaining initial performance parameters and target performance parameters of the piezoelectric element 11 .

[0067] In some embodiments, the piezoelectric element 11 is in the shape of a rectangular block, and the polarization direction of the piezoelectric element 11 is defined as its thickness direction, and the thickness T extends along the Z axis of the rectangular coordinate system; the direction parallel to the axis of the first electrode wire 12 is defined as its length direction, and the length L extends along the X axis of the rectangular coordinate system; the other direction perpendicular to the thickness direction and the length direction is defined as its width direction, and the width W extends along the Y axis of the rectangular coordinate system; the length L is much larger than the thickness T and the width W, and the width W and the thickness T are comparable in size.

[0068] In some embodiments, the initial performance parameters include the material density ρ of the piezoelectric element 11, multiple sets of elastic compliance constants and the stress component σ of the piezoelectric element 11 in the length direction x , the stress component σ in the width direction y , the stress component σ in the thickness direction z .

[0069] In some embodiments, the elastic compliance constant The subscript i represents the polarization direction of the piezoelectric element 11, and the subscript j represents the vibration direction of the piezoelectric element 11. The value 1 represents the X direction, 2 represents the Y direction, and 3 represents the Z direction. The unit is (×10 - 12 m 2 / N); In this embodiment, only the stretching vibration of the piezoelectric element 11 is considered. Multiple groups of elastic compliance constants The first elastic compliance constant of the piezoelectric element 11 is as follows: The second elastic compliance constant of the piezoelectric element 11 is: The third elastic compliance constant of the piezoelectric element 11 is: The fourth elastic compliance constant of the piezoelectric element 11 is:

[0070] In some embodiments, the target performance parameters include the target resonant frequency f0 and the target aspect ratio of the piezoelectric element 11.

[0071] S220, constructing calculation models of the apparent compliance constants of the piezoelectric element 11 in the width direction and the thickness direction respectively.

[0072] In some embodiments, step S220 further includes:

[0073] S221, based on the piezoelectric equation, construct the strain component calculation model of the piezoelectric element 11 in the length direction, width direction and thickness direction respectively. The strain component calculation model is as follows (1)-(3):

[0074]

[0075]

[0076]

[0077] Among them, ε y ,ε zare the strain components of the piezoelectric element 11 in the Y and Z directions respectively. According to the above-mentioned embodiment 1, the size of the piezoelectric element 11 satisfies that no coupling effect is generated in its length direction. Therefore, the strain component of the piezoelectric element 11 in the X direction in formula (3) is 0.

[0078] S222, calculating the Poisson's ratio of the piezoelectric element 11 in multiple directions.

[0079] In some embodiments, the Poisson's ratio V ij That is, the ratio of the strain of the piezoelectric element 11 in different directions, let:

[0080]

[0081] S223, construct a coupling coefficient calculation model for the vibration of the piezoelectric element 11 in the thickness direction and the width direction.

[0082] In some embodiments, the coupling coefficient of the piezoelectric element 11 vibrating in the thickness direction and the width direction is defined as n, and the coupling coefficient calculation model is:

[0083] n=-σ z / σ y (5)

[0084] S224, based on the strain component calculation model, Poisson's ratio and coupling coefficient calculation model, construct the strain component calculation model of the piezoelectric element 11 in the width direction and the thickness direction respectively.

[0085] In some embodiments, according to the above formulas (1) to (5), the strain component calculation models of the piezoelectric element 11 in the width direction and the thickness direction are respectively:

[0086]

[0087]

[0088] In some embodiments, the calculation model of the apparent compliance constant of the piezoelectric element 11 in the width direction and the thickness direction can be further obtained according to the above equations (6) and (7):

[0089]

[0090]

[0091] S230, constructing a resonance frequency model of the piezoelectric element 11 when a two-dimensional fundamental frequency resonance occurs.

[0092] In some embodiments, step S230 further includes:

[0093] S231, constructing a first resonant frequency model and a second resonant frequency model respectively, wherein the first resonant frequency model is associated with the width of the piezoelectric element 11, and the second resonant frequency model is associated with the thickness of the piezoelectric element 11, wherein the first resonant frequency model is:

[0094]

[0095] The second resonant frequency model is:

[0096]

[0097] In the above equations (10) and (11), f0 is the fundamental resonance frequency of the piezoelectric element 11, and ρ is the density of the piezoelectric element 11, with the unit of (kg / m).

[0098] S240, constructing a correlation model between the width-to-thickness ratio and the thickness-frequency constant of the piezoelectric element 11 according to the apparent compliance constant calculation model and the resonance frequency model.

[0099] In some embodiments, the width-to-thickness ratio of the piezoelectric element 11 is The thickness frequency constant is f0T. Through the above formulas (1) to (11), the width-to-thickness ratio calculation model and the thickness frequency constant calculation model of the piezoelectric element 11 can be obtained, where the width-to-thickness ratio calculation model is:

[0100]

[0101] The calculation model of thickness frequency constant is:

[0102]

[0103] S250, based on the initial performance parameters and the target performance parameters, determine the size of the piezoelectric element 11 through the correlation model.

[0104] In some embodiments, step 250 further specifically includes: obtaining a set of coupling coefficients n of the piezoelectric element 11 vibrating in the thickness direction and the width direction, determining the values ​​of several aspect ratios and thickness frequency constants based on the correlation model, and determining the size of the piezoelectric element 11 based on the target performance parameters.

[0105] In some embodiments, after obtaining the initial performance parameters, V 12 、V 13 、V 31 are all constants. Based on a series of coupling coefficients n, a series of and f0T, and a series of numerical values ​​of the two are mapped in the relationship curve. When designing the ultrasonic transducer, when the target resonant frequency f0 of the piezoelectric element 11 and the target width-to-thickness ratio After determination, the width W and thickness T of the piezoelectric element 11 can be determined according to the above relationship curve. After the width W and thickness T of the piezoelectric element 11 are determined, the length L can be selected as needed. The length L preferably needs to be at least 3 times the thickness T and width W to avoid the coupling effect of the piezoelectric element 11 in the length direction.

[0106] In one embodiment, a target resonant frequency f0 is designed to be 2 MHz and a target width-to-thickness ratio Taking the two-dimensional composite vibration ultrasonic transducer of 1.5 as an example, its initial performance parameters are: 12.3×10 -12 m 2 / N, =-4.05×10 -12 m 2 / N, =-5.31×10 -12 m 2 / N, 15.5×10 -12 m 2 / N, the material density ρ of the piezoelectric element 11 is 7500 kg / m, according to the above formula (4), V 12 =0.33, V 13 =0.43, V 31 =0.34, and then according to the above formulas (12) and (13), the thickness frequency constant f0T and the width-to-thickness ratio are obtained The relationship curve, such as Figure 4 ,Depend on Figure 4 It can be seen that when the width-to-thickness ratio When it is 1.5, the thickness frequency constant f0T of the piezoelectric element 11 is about 1070 Hz·m. At this time, it can be calculated that the thickness T is about 0.54 mm and the width W is about 0.8 mm. Then the length L is selected as needed. The length L is preferably more than 3 times the thickness T and / or width W.

[0107] In some embodiments, the aspect ratio of the piezoelectric element 11 is configured to be 0.3-3, the length of the piezoelectric element 11 is configured to be more than 3 times its thickness and / or width, and the frequency is 20 KHz to 10 MHz.

[0108] In one embodiment of the present invention, an electronic device is also provided, which includes at least one processor and a memory, wherein the memory is used to store one or more programs. When the one or more programs are executed by the processor, the processor can implement the two-dimensional composite vibration ultrasonic transducer design method as described above.

[0109] In one embodiment of the present invention, a readable storage medium is also provided, on which a two-dimensional composite vibration ultrasonic transducer design program is stored. When the two-dimensional composite vibration ultrasonic transducer design program is executed by a processor, steps S210 to S250 can be implemented.

[0110] A person of ordinary skill in the art will appreciate that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk, or an optical disk, etc.

[0111] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A two-dimensional composite vibration ultrasonic transducer, characterized in that: It comprises at least one ultrasonic transmitting unit, wherein the ultrasonic transmitting unit comprises a first electrode wire, a second electrode wire and a piezoelectric element; The first electrode wire is arranged at the central axis, the two piezoelectric elements are electrically connected to the two axial sides of the first electrode wire respectively, and the two piezoelectric elements are configured as rectangular blocks of the same size, and the two second electrode wires are electrically connected to the two piezoelectric elements respectively and extend in the axial direction; The size of the piezoelectric element satisfies that: when the piezoelectric element is excited, the resonant frequencies of the piezoelectric element in the thickness direction and the width direction can be coupled to the same frequency, generating two-dimensional composite vibration in the thickness direction and the width direction; The two-dimensional composite vibration ultrasonic transducer is applied to ultrasound-assisted thrombolysis, and the size of the piezoelectric element also satisfies that: no coupling effect occurs in the length direction of the piezoelectric element.

2. The two-dimensional composite vibration ultrasonic transducer according to claim 1, characterized in that: The ratio of the width to the thickness of the piezoelectric element is negatively correlated with the thickness frequency constant of the piezoelectric element.

3. The two-dimensional composite vibration ultrasonic transducer according to claim 2, characterized in that: The thickness frequency constant is negatively correlated with the material density of the piezoelectric element.

4. The two-dimensional composite vibration ultrasonic transducer according to claim 3, characterized in that: The ratio of the width to the thickness of the piezoelectric element is configured to be 0.3-3, and the length of the piezoelectric element is configured to be more than 3 times the thickness and / or width.

5. The two-dimensional composite vibration ultrasonic transducer according to any one of claims 1 to 4, characterized in that: The thickness direction of the piezoelectric element is the polarization direction, the length direction of the piezoelectric element is the direction parallel to the axis of the first electrode wire, and the width direction of the piezoelectric element is another direction perpendicular to the thickness direction and the length direction.

6. A method for designing a two-dimensional composite vibration ultrasonic transducer, the method being used to design the two-dimensional composite vibration ultrasonic transducer as claimed in any one of claims 1 to 5, characterized in that: include: Obtaining initial performance parameters and target performance parameters of the piezoelectric element; Constructing calculation models of the apparent compliance constants of the piezoelectric element in the width direction and the thickness direction respectively; Constructing a resonant frequency model of the piezoelectric element when a two-dimensional fundamental frequency resonance occurs; Constructing a correlation model between the aspect ratio and the thickness frequency constant of the piezoelectric element according to the apparent compliance constant calculation model and the resonance frequency model; Based on the initial performance parameter and the target performance parameter, determining the size of the piezoelectric element through the correlation model; The step of respectively constructing the calculation model of the apparent compliance constant of the piezoelectric element in the width direction and the thickness direction further specifically includes: Based on the piezoelectric equation, a strain component calculation model of the piezoelectric element in the length direction, the width direction and the thickness direction is constructed respectively; Calculating the Poisson's ratio of the piezoelectric element in multiple directions; Constructing a coupling coefficient calculation model for the piezoelectric element vibrating in the thickness direction and the width direction; Based on the strain component calculation model, the Poisson's ratio and the coupling coefficient calculation model, strain component calculation models of the piezoelectric element in the width direction and the thickness direction are constructed respectively.

7. The design method according to claim 6, characterized in that: The initial performance parameters include the material density of the piezoelectric element, multiple groups of elastic compliance constants, and stress components of the piezoelectric element in the length direction, the width direction, and the thickness direction, wherein the multiple groups of elastic compliance constants include: a first elastic compliance constant of the piezoelectric element in which the polarization direction is the length direction and the vibration direction is also the length direction, a second elastic compliance constant of the piezoelectric element in which the polarization direction is the length direction and the vibration direction is the width direction, a third elastic compliance constant of the piezoelectric element in which the polarization direction is the length direction and the vibration direction is the thickness direction, and a fourth elastic compliance constant of the piezoelectric element in which the polarization direction is the thickness direction and the vibration direction is also the thickness direction; The target performance parameters include a target resonant frequency and a target aspect ratio of the piezoelectric element.

8. The design method according to claim 6, characterized in that: In the step of constructing the resonant frequency model of the piezoelectric element when the two-dimensional fundamental frequency resonance occurs, it includes: A first resonant frequency model and a second resonant frequency model are constructed respectively, wherein the first resonant frequency model is associated with the width of the piezoelectric element, and the second resonant frequency model is associated with the thickness of the piezoelectric element.

9. The design method according to claim 6, characterized in that: The step of determining the size of the piezoelectric element based on the initial performance parameter and the correlation model includes: Obtaining a set of coupling coefficients of the piezoelectric element vibrating in the thickness direction and the width direction; Based on the correlation model, determining values ​​of several aspect ratios and thickness frequency constants; Based on the target performance parameter, the size of the piezoelectric element is determined.

10. An electronic device, characterized in that: include: one or more processors; A memory for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the two-dimensional composite vibration ultrasonic transducer design method as described in any one of claims 6 to 9.

11. A readable storage medium, characterized in that: The readable storage medium stores a two-dimensional composite vibration ultrasonic transducer design program, and when the design program is executed by the processor, it can implement the two-dimensional composite vibration ultrasonic transducer design method as described in any one of claims 6-9.

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