WO2022104683A1

WO2022104683A1 - Array-type ultrasonic transducer and manufacturing method therefor

Info

Publication number: WO2022104683A1
Application number: PCT/CN2020/130397
Authority: WO
Inventors: 马腾; 张琪; 黄继卿; 李永川; 郑海荣
Original assignee: 深圳先进技术研究院
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2022-05-27

Abstract

An array-type ultrasonic transducer and a manufacturing method therefor. Said transducer comprises a plurality of ultrasonic transducing units (100) in an array arrangement, and each ultrasonic transducing unit (100) comprises: a backing layer (110), a circuit layer being exposed on a surface of one side of the backing layer (110); a piezoelectric layer (120) located on the side of the backing layer (110) having the circuit layer, the piezoelectric layer (120) comprising a piezoelectric layer body and electrodes located on a surface of a side of the piezoelectric layer body facing toward the backing layer (110) and a surface of a side facing away from the backing layer (110); an acoustic artificial structure (130) located on a side of the piezoelectric layer (120) facing away from the backing layer (110), the acoustic artificial structure (130) comprising: an acoustic impedance matching layer (131) and an acoustic metasurface (132); wherein the acoustic metasurface (132) is located between the acoustic impedance matching layer (131) and the piezoelectric layer (120), or the acoustic metasurface (132) is located on a side of the acoustic impedance matching layer (131) facing away from the backing layer (110). The ultrasonic transducing units (100) can solve the problem of an impedance mismatch between an ultrasonic transducing unit (100) and a target object by means of the acoustic impedance matching layers (131), output bandwidth and amplitude response of an ultrasonic transducing unit (100) is improved, and imaging resolution and sensitivity thereof are increased.

Description

Array type ultrasonic transducer and method of making the same

technical field

The invention relates to the technical field of ultrasonic transducers, and more particularly, to an array type ultrasonic transducer and a manufacturing method thereof.

Background technique

In recent years, the use of novel physical properties and effects of phononic crystals and acoustic metamaterial surfaces to improve the acoustic matching performance of ultrasonic transducers has been reported by many scholars. As synthetic composite structural materials, acoustic metamaterials are composed of sub-wavelength-scale structural units (or artificial "atoms"), which can exhibit equivalent material parameters that natural materials do not possess, such as negative mass density, Negative elastic modulus, near-zero refractive index and extreme anisotropy, etc. Different from other artificial materials such as phononic crystals, the macroscopic physical properties of acoustic metamaterials mainly depend on the local properties of their structural units rather than the long-range interactions between them. This enables us to design macroscopic material parameters on demand at the "atomic" scale, and more easily construct spatial gradient distributions, thereby enabling anomalous manipulation of acoustic waves. The performance of existing ultrasonic transducer devices has yet to be improved.

SUMMARY OF THE INVENTION

In view of this, the present invention provides an array ultrasonic transducer and a manufacturing method thereof, which effectively solve the technical problems existing in the prior art, and the array ultrasonic transducer provided by the present invention has high performance.

For achieving the above object, the technical scheme provided by the invention is as follows:

An array type ultrasonic transducer, comprising a plurality of ultrasonic transducer units arranged in an array, the ultrasonic transducer units comprising:

a backing layer, the circuit layer is exposed on one side of the backing layer;

A piezoelectric layer located on the side of the backing layer with the circuit layer, the piezoelectric layer includes a piezoelectric layer body, and a surface of the piezoelectric layer body on the side facing the backing layer and away from the electrodes on one side of the backing layer;

And, an acoustic artificial structure located on the side of the piezoelectric layer away from the backing layer, the acoustic artificial structure comprising: an acoustic impedance matching layer and an acoustic metasurface; wherein, the acoustic metasurface is located on the acoustic metasurface Between the impedance matching layer and the piezoelectric layer, or the acoustic metasurface is located on the side of the acoustic impedance matching layer away from the backing layer.

Optionally, the acoustic impedance matching layer includes a first acoustic impedance matching sub-layer to an N-th acoustic impedance matching sub-layer that are sequentially superimposed along the direction from the backing layer to the piezoelectric layer, where N is greater than or equal to 1. Integer.

Optionally, the acoustic metasurface includes a circular center portion and a first annular portion to an M-th annular portion, where M is an integer greater than or equal to 1; the first annular portion surrounds the circular center part, the i+1 th annular part surrounds the i th annular part, between the first annular part and the circular center part and between the i+1 th annular part and the i th annular part All are in the shape of annular grooves, and i is an integer greater than or equal to 1 and less than M;

Alternatively, the acoustic metasurface comprises arranging a plurality of strips side by side, at least one strip having a height different from the rest of the strips in the direction from the backing layer to the piezoelectric layer, and/ Or, in the arrangement direction of the plurality of strip-shaped parts, the width of at least one strip-shaped part is different from the width of the other strip-shaped parts, and/or the side of the strip-shaped part facing away from the backing layer is wedge-shaped, And/or, the strip part is a hollow strip part, and/or, the material of at least one strip part is different from the material of the other strip parts;

Alternatively, the side of the acoustic metasurface facing away from the backing layer is a wavy surface.

Optionally, the material of the acoustic impedance matching layer is a polymer material or a metal material.

Optionally, the material of the acoustic metasurface is a polymer material.

Optionally, the piezoelectric layer body is made of piezoelectric ceramic, piezoelectric ceramic composite material, pressure point single crystal material or piezoelectric single crystal composite material.

Optionally, the material of the backing layer includes epoxy resin, and the material of the backing layer further includes at least one of tungsten powder and alumina powder.

Optionally, the plurality of ultrasonic transducer units are arranged in a matrix.

Correspondingly, the present invention also provides a manufacturing method of an array ultrasonic transducer, wherein the array ultrasonic transducer includes a plurality of ultrasonic transducer units arranged in an array, and the fabrication method of the ultrasonic transducer unit:

forming a backing layer, and the circuit layer is exposed on one side of the backing layer;

A piezoelectric layer is formed on the side of the backing layer with the circuit layer, the piezoelectric layer includes a piezoelectric layer body, and a surface of the piezoelectric layer body on the side facing the backing layer and away from the backing layer is formed. an electrode on one side surface of the backing layer;

forming an acoustic artificial structure on the side of the piezoelectric layer away from the backing layer, the acoustic artificial structure includes: an acoustic impedance matching layer and an acoustic metasurface grown by a forward growth process; wherein, the acoustic ultrasound The textured surface is located between the acoustic impedance matching layer and the piezoelectric layer, or the acoustic metasurface is located on the side of the acoustic impedance matching layer away from the backing layer.

Optionally, the acoustic impedance matching layer grown by the forward growth process includes:

The acoustic impedance matching layer is grown by a thermal evaporation coating process or a magnetron sputtering process.

Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

The invention provides an array type ultrasonic transducer and a manufacturing method thereof, comprising a plurality of ultrasonic transducer units arranged in an array, wherein the ultrasonic transducer unit comprises: a backing layer, and one side surface of the backing layer is exposed circuit layer; a piezoelectric layer located on the side of the backing layer with the circuit layer, the piezoelectric layer includes a piezoelectric layer body, and a surface located on the side of the piezoelectric layer body facing the backing layer and an electrode facing away from the side surface of the backing layer; and an acoustic artificial structure located on the side of the piezoelectric layer facing away from the backing layer, the acoustic artificial structure comprising: an acoustic impedance matching layer and an acoustic metasurface; Wherein, the acoustic metasurface is located between the acoustic impedance matching layer and the piezoelectric layer, or the acoustic metasurface is located on the side of the acoustic impedance matching layer away from the backing layer.

It can be seen from the above that the ultrasonic transducer unit provided by the present invention can solve the problem of impedance mismatch between the ultrasonic transducer unit and the target object through the acoustic impedance matching layer, improve the output bandwidth and amplitude response of the ultrasonic transducer unit, and increase the Its imaging resolution and sensitivity. In addition, the ultrasonic transducer unit can correct the sound field distortion generated during the adjustment of beam control, deflection, and beam focusing through the acoustic metasurface. At the same time, the imaging resolution and signal-to-noise ratio of the ultrasonic transducer unit can be further improved. And an array ultrasonic transducer is obtained by arranging a plurality of ultrasonic transducer units in an array, thereby improving the applicable range and performance of the array ultrasonic transducer. At the same time, the present invention uses the forward growth process to grow the acoustic impedance matching layer, thereby improving the thickness accuracy of the acoustic impedance matching layer and further improving the performance of the array ultrasonic transducer.

Description of drawings

1 is a schematic structural diagram of an array ultrasonic transducer provided by an embodiment of the present invention;

2 is a schematic structural diagram of an ultrasonic transducer unit according to an embodiment of the present invention;

3 is a schematic structural diagram of another ultrasonic transducer unit provided by an embodiment of the present invention;

4 is a schematic structural diagram of another ultrasonic transducer unit provided by an embodiment of the present invention;

5a is a schematic structural diagram of an acoustic metasurface provided by an embodiment of the present invention;

Figure 5b is a sectional view in the direction of AA' in Figure 5a;

6 is a schematic structural diagram of another acoustic metasurface provided by an embodiment of the present invention;

7 is a schematic structural diagram of yet another acoustic metasurface provided by an embodiment of the present invention;

8 is a schematic structural diagram of yet another acoustic metasurface provided by an embodiment of the present invention;

9 is a schematic structural diagram of another acoustic metasurface provided by an embodiment of the present invention;

10 is a schematic structural diagram of yet another acoustic metasurface provided by an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of still another acoustic metasurface provided by an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

As mentioned in the background art, in recent years, many scholars have reported using the novel physical properties and effects of acoustic metamaterials to improve the acoustic matching performance of ultrasonic transducers. Ultrasound transducers are key components in ultrasound equipment and can be used for ultrasound imaging, ultrasound stimulation, ultrasound therapy, acoustic manipulation, and more. The performance of existing ultrasonic transducer devices has yet to be improved.

Based on this, the embodiments of the present invention provide an array ultrasonic transducer and a manufacturing method thereof, which effectively solve the technical problems existing in the prior art, and the array ultrasonic transducer provided by the embodiments of the present invention has high performance.

To achieve the above purpose, the technical solutions provided by the embodiments of the present invention are as follows, and the technical solutions provided by the embodiments of the present invention are described in detail with reference to FIG. 1 to FIG. 11 .

1 to 3, FIG. 1 is a schematic structural diagram of an array ultrasonic transducer provided by an embodiment of the present invention, and FIG. 2 is a structural schematic diagram of an ultrasonic transducer unit provided by an embodiment of the present invention. 3 is a schematic structural diagram of another ultrasonic transducer unit provided in an embodiment of the present invention. The array type ultrasonic transducer includes a plurality of ultrasonic transducer units 100 arranged in an array, and the ultrasonic transducer units include:

The backing layer 110 has a bare circuit layer on one surface of the backing layer 110 .

The backing layer 110 has a piezoelectric layer 120 on one side of the circuit layer, the piezoelectric layer 120 includes a piezoelectric layer body, and a surface of the piezoelectric layer body on the side facing the backing layer 110 and an electrode facing away from the surface of the backing layer 110 .

And, the acoustic artificial structure 130 located on the side of the piezoelectric layer 120 away from the backing layer 110, the acoustic artificial structure 130 includes: an acoustic impedance matching layer 131 and an acoustic metasurface 132; wherein, the acoustic ultrasound The structured surface 132 is located between the acoustic impedance matching layer 131 and the piezoelectric layer 120 (as shown in FIG. 2 ). Or the acoustic metasurface 132 is located on the side of the acoustic impedance matching layer 131 away from the backing layer 110 (as shown in FIG. 3 ).

In an embodiment of the present invention, the plurality of ultrasonic transducer units provided by the present invention may be arranged in a matrix, which is not specifically limited by the present invention.

It can be understood that the ultrasonic transducer unit provided by the embodiment of the present invention can solve the problem of impedance mismatch between the ultrasonic transducer unit and the target object through the acoustic impedance matching layer, improve the output bandwidth and amplitude response of the ultrasonic transducer unit, and increase the performance of the ultrasonic transducer unit. Great for its imaging resolution and sensitivity. In addition, the ultrasonic transducer unit can correct the sound field distortion generated during the adjustment of beam control, deflection, and beam focusing through the acoustic metasurface. At the same time, the imaging resolution and signal-to-noise ratio of the ultrasonic transducer unit can be further improved. And an array ultrasonic transducer is obtained by arranging a plurality of ultrasonic transducer units in an array, thereby improving the applicable range and performance of the array ultrasonic transducer. Meanwhile, the embodiment of the present invention uses the forward growth process to grow the acoustic impedance matching layer, thereby improving the thickness accuracy of the acoustic impedance matching layer and further improving the performance of the array ultrasonic transducer.

Further, the ultrasonic transducer unit provided by the embodiment of the present invention can also achieve sub-wavelength focusing and super-imaging effects that break through the diffraction limit through an acoustic artificial structure.

In an embodiment of the present invention, the acoustic impedance matching layer provided by the embodiment of the present invention is used to match the impedance between the ultrasonic transducer unit and the target object, wherein the acoustic impedance matching unit may be a single-layer structure, or the acoustic impedance matching unit may also for multiple stacked structures. As shown in FIG. 4 , it is a schematic structural diagram of still another ultrasonic transducer unit provided by an embodiment of the present invention, wherein the acoustic impedance matching layer 131 provided by the embodiment of the present invention includes the backing layer 110 to the From the first acoustic impedance matching sub-layer 1311 to the N-th acoustic impedance matching sub-layer 131n that are sequentially stacked in the direction of the piezoelectric layer 120 , N is an integer greater than or equal to 1.

In an embodiment of the present invention, the acoustic metasurface provided by the embodiment of the present invention is used to change the transmission characteristics of sound waves, such as reflection and focusing at any point, perfect low-frequency sound absorption, self-bending sound beams, spiral sound waves, and asymmetric transmission of sound energy etc., the embodiments of the present invention do not specifically limit the structure of the acoustic metasurface, which may be a multi-circle nested structure, a multi-layer structure, a gradient structure, or the like. As shown in Fig. 5a and Fig. 5b, Fig. 5a is a schematic structural diagram of an acoustic metasurface provided by an embodiment of the present invention, and Fig. 5b is a cross-sectional view along the AA' direction in Fig. 5a, wherein the The acoustic metasurface 132 includes a circular central portion 1320 and a first annular portion 1321 to an M-th annular portion 132m, where M is an integer greater than or equal to 1.

The first annular portion 1321 surrounds the circular central portion 1320 , the i+1-th annular portion surrounds the i-th annular portion, and the distance between the first annular portion 1321 and the circular central portion 1320 Both the i+1 th annular portion and the i th annular portion are in the shape of an annular groove, and i is an integer greater than or equal to 1 and less than M.

It can be understood that the depth of the groove structure between the first annular portion and the circular center portion provided by the embodiment of the present invention and the depth of the groove structure between the i+1 th annular portion and the i th annular portion are different. To make specific restrictions, it can penetrate the acoustic metasurface, which needs to be specifically designed according to the actual application.

Alternatively, as shown in FIG. 6 , the acoustic metasurface includes a plurality of strip-shaped parts 132a arranged side by side, and in the direction from the backing layer to the piezoelectric layer, the height h1 of at least one strip-shaped part 132a is the same as that of the other strip-shaped parts 132a. The heights of the bar-shaped portions 132a are different (for example, they may be set in a gradient, wherein the height of each bar-shaped portion needs to be adjusted according to actual applications), and/or, as shown in FIG. 7 , the plurality of bar-shaped portions are arranged in the In the direction, the width h2 of at least one strip portion 132a is different from the widths of the other strip portions (wherein the width of each strip portion needs to be adjusted according to the actual application), and/or, as shown in FIG. The side of the shaped portion 132a facing away from the backing layer is wedge-shaped (wherein the wedge-shaped angle of each strip portion needs to be specifically adjusted according to practical applications). And/or, as shown in FIG. 9 , the strip portion 132a is a hollow strip portion, and/or the material of at least one strip portion is different from the material of the other strip portions.

Alternatively, as shown in FIG. 10 , the side of the acoustic metasurface 132 away from the backing layer is a wavy surface, which is not specifically limited in the present invention, and a specific shape of the acoustic metasurface is designed as required.

The ultrasonic transducer unit transmitted in the embodiment of the present invention includes a backing layer, a piezoelectric layer, an acoustic impedance matching layer, an acoustic metasurface, etc. In order to study the influence of each layer structure on the electrical and acoustic performance of the ultrasonic transducer unit, First, a physical model equivalent to its structure is established. Among them, the main structure of the ultrasonic transducer unit includes a piezoelectric layer, an acoustic impedance matching layer, an acoustic metasurface and a backing layer. This will be based on the microwave transmission line theory and through the Mason electromechanical equivalent circuit to model and analyze the ultrasonic transducer. The relationship between the acoustic impedance matching of the unit and the structural parameters of each layer. The mechanical vibration of each layer will be equivalent to a part of the circuit. The acoustic impedance matching network theory is applied to the parameter design of the acoustic impedance matching layer, and the transmission matrix is used to calculate the acoustic wave transmission efficiency under the action of the acoustic impedance matching layer. Wherein, the static capacitance C0, electromechanical conversion coefficient N, longitudinal wave velocity Cp, wave number k, and acoustic impedance Zp of the piezoelectric layer material provided by the embodiment of the present invention are respectively:

_k =ω/cp

Z _p = ρc _p

where ρ, A, t _p ,

_h33 ,

respectively represent the density, area, thickness, elastic stiffness constant, piezoelectric constant and dielectric constant of the piezoelectric layer material, and then the optimal parameters are obtained by optimizing the piezoelectric layer material.

And, the embodiment of the present invention takes the acoustic impedance matching layer including the first acoustic impedance matching sub-layer to the third acoustic impedance matching sub-layer as an example, wherein Z _a is the acoustic impedance of the first acoustic impedance matching sub-layer, and Z _b is the second acoustic impedance matching sub-layer. The acoustic impedance of the acoustic impedance matching sub-layer, Z _c is the acoustic impedance of the third acoustic impedance matching sub-layer, Z _l is the acoustic impedance of the propagation medium between the acoustic impedance matching layer and the target object, and _ta is the first acoustic impedance matching sub-layer. layer thickness, t _b is the thickness of the second acoustic impedance matching sublayer, t _c is the thickness of the third acoustic impedance matching sublayer, _{ka is the wavenumber of the first acoustic impedance matching sublayer, and k b} _is the second acoustic impedance The wave number of the matching sub-layer, k _c is the wave number of the third acoustic impedance matching sub-layer, and the equivalent input impedance of each layer matching is derived through the equivalent circuit (Zin1 is the equivalent input impedance of the first acoustic impedance matching sub-layer, Zin2 is the equivalent input impedance of the second acoustic impedance matching sublayer, and Zin3 is the equivalent input impedance of the third acoustic impedance matching sublayer) respectively:

After calculation, the material selection and thickness parameters of each acoustic impedance matching sub-layer are determined, and then a finite element model is established through finite element simulation software (such as COMSOL Multiphysics) for sound field analysis to further optimize the effect of the acoustic impedance matching layer. Optionally, the material of the acoustic impedance matching layer provided by the implementation of the present invention is a polymer material (wherein the acoustic impedance matching layer of the polymer material can be prepared by the forward growth technology of thermal evaporation coating) or a metal material (wherein The acoustic impedance matching layer of metal material can be prepared by the forward growth technology of magnetron sputtering). Specifically, the material of the acoustic impedance matching layer provided in the embodiment of the present invention may be parylene or gold, which may also be other materials in other embodiments of the present invention, which is not specifically limited in the present invention.

And, the acoustic metasurface provided by the embodiment of the present invention may include a circular central portion, a first annular portion, and a second annular portion, wherein the principles of Kirchhoff diffraction theory and Fresnel zone plate theory are used as the principles , to establish the theoretical model of the plane Fresnel acoustic lens of the acoustic metasurface of the circular structure. It can be seen from the half-wave band method that the acoustic artificial focusing structure parameters can make the sound field of the ultrasonic transducer unit produce a focusing effect when the following formulas are satisfied:

Among them, F represents the designed focal length, λ represents the wavelength of the sound wave in the transmission medium, and m (m=1, 2, 3...) represents the number of turns of the circular structure (that is, the central part of the circle is the first circle, the first annular part For the second circle, and so on, as shown in Figure 11), the more the number of circles, the higher the transmission efficiency of the sound wave, but at the same time the fabrication of the Fresnel acoustic lens will become more complicated. For example, when m (for example, m=3) circles of acoustic metasurface are prepared on the ultrasonic transducer unit, the thickness h of the acoustic metasurface can be designed by the following formula:

where c0 is the sound speed of the propagation medium between the ultrasonic transducer unit and the target object, c1 is the sound speed of the material of the acoustic metasurface,

Represents the phase change of a sound wave as it exits through an acoustic metasurface. Optionally, the material of the acoustic metasurface provided in the embodiment of the present invention may be a polymer material, such as parylene, wherein, considering that the transmission efficiency of sound waves is also affected by the acoustic impedance of the material, Based on the theoretical calculation and finite element simulation verification of acoustic artificial structures, for example, parylene with acoustic impedance parameters closer to water is selected as the material for preparing acoustic metasurfaces. Specifically, high-precision photolithography micromachining technology or 3D microfabrication technology can be used. It is produced by printing technology, which ensures high production precision; this is not specifically limited in the present invention, and other materials may also be used in other embodiments of the present invention.

In addition, the piezoelectric layer body provided in the embodiment of the present invention is made of piezoelectric ceramic, piezoelectric ceramic composite material, pressure point single crystal material or piezoelectric single crystal composite material. And, the backing layer of the ultrasonic transducer unit is prepared by using a material with high sound absorption performance to further reduce the size of the ultrasonic transducer unit. Optionally, the material of the backing layer provided in the embodiment of the present invention includes epoxy resin, And the material of the backing layer also includes at least one of tungsten powder and aluminum oxide powder. Specifically, epoxy resin, tungsten powder, and aluminum oxide powder can be formed into a mixed material.

Correspondingly, an embodiment of the present invention also provides a method for manufacturing an array ultrasonic transducer, wherein the array ultrasonic transducer includes a plurality of ultrasonic transducer units arranged in an array. method:

It can be understood that, after a plurality of ultrasonic transducer units are obtained by the above manufacturing method, all ultrasonic transducer units are arranged in a preset arrangement to obtain an array ultrasonic transducer.

In an embodiment of the present invention, the acoustic impedance matching layer grown by the forward growth process provided by the present invention includes:

The acoustic impedance matching layer is grown by a thermal evaporation coating process or a magnetron sputtering process, and a preparation process needs to be specifically selected according to the specific material of the acoustic impedance matching degree, which is not specifically limited in the present invention.

Embodiments of the present invention provide an array ultrasonic transducer and a manufacturing method thereof, including a plurality of ultrasonic transducer units arranged in an array, the ultrasonic transducer units comprising: a backing layer, one side of the backing layer A circuit layer is exposed on the surface; a piezoelectric layer located on the side of the backing layer with the circuit layer, the piezoelectric layer includes a piezoelectric layer body, and a piezoelectric layer located on the side of the piezoelectric layer body facing the backing layer an electrode on the surface and a surface away from the backing layer; and an acoustic artificial structure located on the side of the piezoelectric layer away from the backing layer, the acoustic artificial structure comprising: an acoustic impedance matching layer and an acoustic superstructure surface; wherein, the acoustic metasurface is located between the acoustic impedance matching layer and the piezoelectric layer, or the acoustic metasurface is located on the side of the acoustic impedance matching layer away from the backing layer.

It can be seen from the above that the ultrasonic transducer unit provided by the embodiment of the present invention can solve the problem of impedance mismatch between the ultrasonic transducer unit and the target object through the acoustic impedance matching layer, and improve the output bandwidth and amplitude response of the ultrasonic transducer unit. Increase its imaging resolution and sensitivity. In addition, the ultrasonic transducer unit can correct the sound field distortion generated during the adjustment of beam control, deflection, and beam focusing through the acoustic metasurface. At the same time, the imaging resolution and signal-to-noise ratio of the ultrasonic transducer unit can be further improved. And an array ultrasonic transducer is obtained by arranging a plurality of ultrasonic transducer units in an array, thereby improving the applicable range and performance of the array ultrasonic transducer. Meanwhile, the embodiment of the present invention uses the forward growth process to grow the acoustic impedance matching layer, thereby improving the thickness accuracy of the acoustic impedance matching layer and further improving the performance of the array ultrasonic transducer.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

An array type ultrasonic transducer, characterized in that it includes a plurality of ultrasonic transducer units arranged in an array, and the ultrasonic transducer units include:

a backing layer, the circuit layer is exposed on one side of the backing layer;

A piezoelectric layer located on the side of the backing layer with the circuit layer, the piezoelectric layer includes a piezoelectric layer body, and a surface of the piezoelectric layer body on the side facing the backing layer and away from the electrodes on one side of the backing layer;

And, an acoustic artificial structure located on the side of the piezoelectric layer away from the backing layer, the acoustic artificial structure comprising: an acoustic impedance matching layer and an acoustic metasurface; wherein, the acoustic metasurface is located on the acoustic metasurface Between the impedance matching layer and the piezoelectric layer, or the acoustic metasurface is located on the side of the acoustic impedance matching layer away from the backing layer.
The array ultrasonic transducer according to claim 1, wherein the acoustic impedance matching layer comprises a first acoustic impedance matching sub-layer to a second acoustic impedance matching sub-layer to a second acoustic impedance matching sub-layer to N acoustic impedance matching sublayers, where N is an integer greater than or equal to 1.
The array ultrasonic transducer according to claim 1, wherein the acoustic metasurface comprises a circular central portion and a first annular portion to an M-th annular portion, where M is an integer greater than or equal to 1 ; The first circular ring portion surrounds the circular central portion, the i+1 circular ring portion surrounds the i-th circular portion, and between the first circular ring portion and the circular central portion and the Both the i+1 annular portion and the i-th annular portion are in the shape of an annular groove, and i is an integer greater than or equal to 1 and less than M;

Alternatively, the acoustic metasurface comprises arranging a plurality of strips side by side, at least one strip having a height different from the rest of the strips in the direction from the backing layer to the piezoelectric layer, and/ Or, in the arrangement direction of the plurality of strip-shaped parts, the width of at least one strip-shaped part is different from the width of the other strip-shaped parts, and/or the side of the strip-shaped part facing away from the backing layer is wedge-shaped, And/or, the strip part is a hollow strip part, and/or, the material of at least one strip part is different from the material of the other strip parts;

Alternatively, the side of the acoustic metasurface facing away from the backing layer is a wavy surface.
The array ultrasonic transducer according to claim 1, wherein the material of the acoustic impedance matching layer is a polymer material or a metal material.
The array ultrasonic transducer according to claim 1, wherein the material of the acoustic metasurface is parylene.
The array ultrasonic transducer according to claim 1, wherein the piezoelectric layer body is made of piezoelectric ceramic, piezoelectric ceramic composite material, pressure point single crystal material or piezoelectric single crystal composite material.
The array ultrasonic transducer according to claim 1, wherein the material of the backing layer comprises epoxy resin.
The array ultrasonic transducer according to claim 1, wherein the plurality of ultrasonic transducer units are arranged in a matrix.
A manufacturing method of an array ultrasonic transducer, characterized in that the array ultrasonic transducer comprises a plurality of ultrasonic transducer units arranged in an array, and the fabrication method of the ultrasonic transducer unit:

forming a backing layer, and the circuit layer is exposed on one side of the backing layer;

A piezoelectric layer is formed on the side of the backing layer with the circuit layer, the piezoelectric layer includes a piezoelectric layer body, and a surface of the piezoelectric layer body on the side facing the backing layer and away from the backing layer is formed. an electrode on one side surface of the backing layer;

forming an acoustic artificial structure on the side of the piezoelectric layer away from the backing layer, the acoustic artificial structure includes: an acoustic impedance matching layer and an acoustic metasurface grown by a forward growth process; wherein, the acoustic ultrasound The textured surface is located between the acoustic impedance matching layer and the piezoelectric layer, or the acoustic metasurface is located on the side of the acoustic impedance matching layer away from the backing layer.
The method for manufacturing an array ultrasonic transducer according to claim 9, wherein the acoustic impedance matching layer grown by a forward growth process comprises:

The acoustic impedance matching layer is grown by a thermal evaporation coating process or a magnetron sputtering process.