Ultrasonic / opto-acoustic dual-mode imaging two-dimensional area array transducer and preparation method thereof

Abstract

The invention provides an ultrasonic / opto-acoustic dual-mode imaging two-dimensional area array transducer and a preparation method thereof, the ultrasonic / opto-acoustic dual-mode imaging two-dimensional area array transducer comprises an ultrasonic transducer and at least two optical signal transmitting devices, the ultrasonic transducer comprises at least two array combinations arranged at intervals, and at least one optical signal transmitting device is arranged between two adjacent array combinations and is used for transmitting optical signals; the array combination comprises at least one single-layer array, and when the number of the single-layer arrays is multiple, the multiple single-layer arrays are distributed in the first direction; each single-layer array comprises a circuit board and a plurality of transducer array elements, the transducer array elements are arranged on the circuit board and distributed in the second direction, and at least one transducer array element is used for transmitting ultrasonic signals; the ultrasonic transducer is configured to receive the ultrasonic echo signal and the photoacoustic echo signal and process the image. By combining optical equipment and ultrasonic equipment, the transducer has the advantages of high spatial resolution of optical imaging and strong penetrating power of ultrasonic imaging, so that the transducer is high in imaging efficiency and good in imaging effect.

Description

Technical Field

[0001] The present application belongs to the field of transducer technology, and specifically relates to an ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer and a preparation method thereof. Background Art

[0002] The study of brain activity and brain function characteristics is a core component of brain science research. At present, the exact mechanism of functional brain diseases is still unclear and there is a lack of effective treatment measures. This is still a scientific and medical challenge faced by the world. Therefore, understanding the spatiotemporal characteristics of brain activity related to the pathology of these functional brain diseases and developing advanced intervention and treatment technologies are major and urgent tasks for the scientific community. Brain activity is different from any other organ in the body in terms of time. The organ and internal sources of the brain receiving and processing perceptions are complex neural signals with high time dependence, which determines the high variability of brain activity in the time dimension, and poses great challenges to the tools, methods and theoretical frameworks of brain science research. Therefore, the development of technologies and methods that can accurately analyze brain functional activities in spatial and temporal dimensions, especially brain function analysis strategies and instruments under living conditions, plays an important role in understanding the fundamental operating laws of the brain and promoting the innovative development of brain science.

[0003] Currently, the equipment available for imaging includes magnetic resonance imaging equipment, photoacoustic imaging equipment, ultrasound imaging equipment, and so on. Although photoacoustic imaging equipment can provide high contrast and blood oxygen metabolism information, its penetration depth is low and it is not suitable for deep brain imaging. Ultrasound imaging equipment can provide information on vascular morphology, blood flow direction, and blood flow velocity, but it cannot provide blood oxygen information and is not suitable for brain imaging. Currently, only magnetic resonance imaging equipment is used clinically to detect the brain, but the equipment is large, expensive, and has limited spatiotemporal resolution. It is impossible to obtain specific brain imaging data, which limits its application in some brain sciences.

[0004] Although some multimodal technologies combining photoacoustics and ultrasound have been proposed, photoacoustic imaging and ultrasound imaging use different imaging principles. It is difficult to combine photoacoustic imaging equipment and ultrasound imaging equipment in actual operation, and it is difficult to simultaneously meet the requirements of equipment size, structural stability, imaging effect, imaging efficiency, and processing difficulty.

[0005] Application Contents

[0006] In order to overcome the defects of the above-mentioned prior art, the present application proposes an ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer and a preparation method thereof. By combining an optical device with an ultrasonic device, the advantages of high spatial resolution of optical imaging and strong penetration of ultrasonic imaging are combined, so that the imaging efficiency of the transducer is high and the imaging effect is good.

[0007] This is achieved specifically through the following technical solutions:

[0008] An ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer comprises an ultrasonic transducer and at least two optical signal emitting devices, wherein at least two of the optical signal emitting devices are arranged on the ultrasonic transducer;

[0009] The ultrasonic transducer comprises at least two array combinations arranged at intervals, at least one optical signal emitting device is arranged between two adjacent array combinations, and the optical signal emitting device is used to emit an optical signal;

[0010] The array combination includes at least one single-layer array, and when there are multiple single-layer arrays, the multiple single-layer arrays are distributed along a first direction; each of the single-layer arrays includes a circuit board and multiple transducer array elements, the multiple transducer array elements are arranged on the circuit board and distributed along a second direction, and at least one transducer array element is used to transmit an ultrasonic signal; the ultrasonic transducer is configured to receive an ultrasonic echo signal corresponding to the ultrasonic signal and a photoacoustic echo signal corresponding to the optical signal, so as to process imaging based on the ultrasonic echo signal and the photoacoustic echo signal.

[0011] In a specific embodiment, the first end of the array assembly and the first end of the optical signal emitting device are directed toward the target tissue, and are used to emit the ultrasonic signal and the optical signal to the target tissue;

[0012] The first ends of all the array assemblies and the first ends of all the optical signal emitting devices together form a plane, an arc surface or an arc-like surface. In a preferred embodiment, the first ends of all the array assemblies and the first ends of all the optical signal emitting devices together form an arc surface, and the curvature of the arc surface is between 2 / π-4 / π.

[0013] In a specific embodiment, the circuit board includes a flexible circuit board, a first portion of the flexible circuit board is located on a first side of the single-layer array, and when the array combination includes a plurality of the single-layer arrays, the plurality of the single-layer arrays are distributed along the first direction, and the transducer array elements of adjacent single-layer arrays are spaced apart by the first portion of the flexible circuit board;

[0014] The second part of the flexible circuit board is connected to the first part of the flexible circuit board and extends a preset length, and the width ratio between an end of the second part of the flexible circuit board away from the first part of the flexible circuit board and an end of the second part of the flexible circuit board close to the first part of the flexible circuit board is greater than 1, and the second part of the flexible circuit board is used to lead out the leads on the flexible circuit board to connect with external electrical components.

[0015] In a specific embodiment, a width ratio between an end of the second part of the flexible circuit board away from the first part of the flexible circuit board and an end of the second part of the flexible circuit board close to the first part of the flexible circuit board is between 1.2 and 2;

[0016] And / or, the second part of the flexible circuit board has a connected extension section and a connecting section, the length of the extension section is greater than the length of the connecting section, and the width of the connecting section away from the extension section is greater than the width of the connecting section close to the extension section.

[0017] In a specific embodiment, it further comprises a substrate, the array assembly is arranged on the substrate, a limiting space is defined between each adjacent array assembly and the substrate, the optical signal emitting device is arranged in the limiting space, and the limiting space is used to limit the position of the optical signal emitting device;

[0018] The optical signal transmitting device includes a plurality of optical fibers, which are distributed along the second direction to form an optical fiber array; each of the optical fibers includes an extension portion, one end of which extends in a direction away from the array combination for connection with an external device, and the other end of the extension portion is provided with a light emitting portion, which is located at the first end of the optical signal transmitting device and faces the target tissue.

[0019] In a specific embodiment, the transducer array element includes a piezoelectric layer, a backing layer and at least one matching layer, at least one matching layer is arranged on one side of the piezoelectric layer, the backing layer is arranged on the other side of the piezoelectric layer, and the first part of the flexible circuit board covers the first side of the backing layer;

[0020] At least one of the matching layers includes a first matching layer and a second matching layer, the first matching layer is arranged on the piezoelectric layer, and the second matching layer is arranged on the first matching layer, the first matching layer and the second matching layer are made of different materials and have different acoustic impedances; the first matching layer and the second matching layer work together to optimize the acoustic impedance to obtain optimal bandwidth and maximum acoustic energy conversion.

[0021] In a specific embodiment, the array combination includes at least two single-layer arrays, and an adhesive is provided between each adjacent single-layer array, and the adjacent single-layer arrays are connected by the adhesive; wherein the number of the single-layer arrays in the array combination is between 2 and 8;

[0022] And / or, there is a preset angle between two adjacent array combinations, and the preset angle is between 0° and 20°.

[0023] In a specific embodiment, an electrode layer is disposed between the backing layer and the piezoelectric layer and on a side of the matching layer away from the piezoelectric layer.

[0024] In a specific embodiment, the height of each single-layer array along the first direction decreases to form a step-like arrangement; or the height of each single-layer array decreases from the outside to the inside to form a V-shaped arrangement; or the height of each single-layer array decreases from the inside to the outside to form a pyramid-like arrangement.

[0025] A preparation method for preparing the above-mentioned ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer, comprising:

[0026] Acquire a plurality of the circuit boards and a plurality of the transducer array elements, arrange at least two of the transducer array elements on each of the circuit boards, and at least two of the transducer array elements are distributed along the second direction, each of the circuit boards and the transducer array elements on the circuit boards constitute the single-layer array, and a plurality of the circuit boards and the plurality of the transducer array elements constitute a plurality of the single-layer arrays;

[0027] Combining a single single-layer array as an array or arranging at least two single-layer arrays along the first direction and bonding them together as an array;

[0028] At least two of the array combinations and at least two of the optical signal emitting devices are staggered along a first direction, two adjacent array combinations define a limiting space, and the optical signal emitting device is placed in the limiting space.

[0029] This application has at least the following beneficial effects:

[0030] The present application proposes an ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer, comprising an ultrasonic transducer and at least two optical signal transmitting devices, wherein the at least two optical signal transmitting devices are arranged on the ultrasonic transducer; the ultrasonic transducer comprises at least two array combinations arranged at intervals, at least one optical signal transmitting device is arranged between two adjacent array combinations, and the optical signal transmitting device is used to transmit optical signals; the array combination comprises at least one single-layer array, and when there are multiple single-layer arrays, the multiple single-layer arrays are distributed along a first direction; each single-layer array comprises a circuit board and multiple transducer array elements, the multiple transducer array elements are arranged on the circuit board and distributed along a second direction, and at least one transducer array element is used to transmit ultrasonic signals; the ultrasonic transducer is configured to receive an ultrasonic echo signal corresponding to the ultrasonic signal and a photoacoustic echo signal corresponding to the optical signal, so as to process imaging based on the ultrasonic echo signal and the photoacoustic echo signal. First, the present application provides an optical signal transmitting device on the ultrasonic transducer, so that at least one optical signal transmitting device is provided on each of the two array combinations, so as to combine the photoacoustic imaging of the optical signal transmitting device and the ultrasonic imaging of the ultrasonic transducer, thereby having the advantages of high spatial resolution of optical imaging and strong penetration of ultrasonic imaging. At the same time, at least two array combinations are arranged at intervals so that the ultrasonic transducer forms a planar array transducer, which improves the resolution and efficiency of detection compared with the existing linear array transducer. Furthermore, considering that the size of the transducer must be ensured while the optical device and the ultrasonic device are provided on the transducer, which has certain difficulties in processing and preparation, based on this, the present application also makes a special design for each array combination, and divides the array combination into at least one single-layer array, each single-layer array is composed of a plurality of transducer array elements distributed along the second direction and a circuit board connected to the transducer array. The array combination under this setting has a plurality of independent single-layer arrays, and the circuit board on each single-layer array can not only transmit electrical signals to the transducer array elements on the circuit board individually, but also play a certain insulation role. The array combination under this setting not only reduces the difficulty of processing, but also makes the array combination structure more stable and reliable. Furthermore, the ultrasonic transducer of the present application can not only receive the ultrasonic echo signal generated after the transducer array element transmits the ultrasonic signal to the target tissue, but also receive the photoacoustic echo signal generated after the optical signal transmitting device transmits the optical signal to the target tissue. Only one device can receive multiple types of echo signals, reduce the design of components, and make the structure of the transducer more small and compact.

[0031] Furthermore, the first end of the array combination and the first end of the optical signal emitting device are oriented toward the target tissue, and are used to emit ultrasonic signals and optical signals to the target tissue; the first ends of all array combinations and the first ends of all optical signal emitting devices together constitute a plane, an arc surface or a quasi-arc surface. In the present application, the first ends of all array combinations and the first ends of all optical signal emitting devices together constitute a plane, an arc surface or a quasi-arc surface through the special design of each array combination and each optical signal emitting device. The transducer under the plane design is easy to prepare and can be suitable for simple application scenarios. In the prior art, transducers can only be prepared into planes. In addition to the plane design, in the present application, under the special design of each array combination and each optical signal emitting device, the dual-mode imaging two-dimensional array transducer can also be prepared into an arc surface or a quasi-arc surface. The optical signal of the optical signal emitting device under the arc surface or the quasi-arc surface design is better emitted to the target tissue to better receive the photoacoustic echo signal generated at the target tissue, thereby improving the photoacoustic and ultrasonic dual-mode imaging effect. Preferably, when the first ends of all array combinations and the first ends of all optical signal emitting devices together form an arc surface, the curvature of the arc surface is between 2 / Π-4 / Π. This curvature design can not only adapt to different application scenarios, but also enable the photoacoustic / ultrasonic dual-mode transducer to transmit optical signals more efficiently, thereby improving the effects of photoacoustic and ultrasonic dual-mode imaging.

[0032] Furthermore, the circuit board includes a flexible circuit board, a first part of the flexible circuit board is located on a first side of a single-layer array, and when the array combination includes multiple single-layer arrays, the multiple single-layer arrays are distributed along a first direction, and adjacent single-layer arrays are separated by the first part of the flexible circuit board; the second part of the flexible circuit board is connected to the first part of the flexible circuit board and extends a preset length, and a width ratio between an end of the second part of the flexible circuit board away from the first part of the flexible circuit board and an end of the second part of the flexible circuit board close to the first part of the flexible circuit board is greater than 1, and the second part of the flexible circuit board is used to lead out the leads on the flexible circuit board for connection with external electrical components. The present application adopts a flexible circuit board to enable the transducer device to better adapt to various complex and compact spatial layouts, thereby improving the overall flexibility and adaptability of the device. By dividing the flexible circuit board into a first part and a second part, the first part of the flexible circuit board is arranged on the first side of the single-layer array, so that the transducer array elements of adjacent single-layer arrays are separated by the first part of the flexible circuit board, so that the array elements in the array combination are independent of each other, so as to reduce the influence of the vibration of a certain array element on other array elements, thereby effectively reducing the crosstalk interference between the array elements, and the width of the second part of the flexible circuit board is specially designed so that the second part of the flexible circuit board can better disperse the leads, optimize the wiring design, and better connect more electrical components.

[0033] Furthermore, the width ratio between the end of the second part of the flexible circuit board away from the first part of the flexible circuit board and the end of the second part of the flexible circuit board close to the first part of the flexible circuit board is between 1.2-2. The present application sets the width of the two ends of the second part of the flexible circuit board so that the second part of the flexible circuit board can better disperse the leads and optimize the wiring design to better connect more electrical components. And / or, the second part of the flexible circuit board has a connected extension section and a connecting section, the length of the extension section is greater than the length of the connecting section, and the width of the connecting section away from the extension section is greater than the width of the connecting section close to the extension section. The present application sets the length of the second part of the flexible circuit board on the extension section and the connecting section, as well as the width of the extension section and the connecting section, so that the flexible circuit board can be extended to a certain extent to adapt to various complex spatial layouts, and the leads can be distributed to a certain extent to facilitate the connection between the leads and electrical components.

[0034] Furthermore, the ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer also includes a substrate, an array assembly is arranged on the substrate, a limiting space is defined between each adjacent array assembly and the substrate, and an optical signal transmitting device includes multiple optical fibers, the multiple optical fibers are arranged in the limiting space, and are distributed along the second direction to form an optical fiber array; each optical fiber includes an extension portion and a light output portion, one end of the extension portion passes through the substrate and extends in a direction away from the array assembly, for connecting with an external device; the other end of the extension portion is provided with a light output portion, the light output portion faces the target tissue, and is used to transmit an optical signal to the target tissue, so as to generate a photoacoustic echo signal at the target tissue. The present application makes the spatial arrangement more reasonable by staggering the array assembly and the optical signal transmitting device on the substrate; at the same time, considering that the optical fiber is relatively soft, a limiting space is defined between the array assembly and the substrate, and multiple optical fibers are arranged in the limiting space to limit the position of the optical fiber and prevent the optical fiber from moving; multiple optical fibers are distributed along the second direction, so that the optical signal emitted by the optical fiber can cover the target tissue in a larger range, so as to improve the imaging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 The main view of the ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer of this application Figure 1 ;

[0037] Figure 2 The main view of the ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer of this application Figure 2 ;

[0038] Figure 3 Schematic diagram of a single-layer array of a two-dimensional array transducer for ultrasound / photoacoustic dual-mode imaging in this application Figure 1 ;

[0039] Figure 4 This is a schematic diagram of the optical fiber array of the ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer of this application;

[0040] Figure 5 The main view of the ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer of this application Figure 2 ;

[0041] Figure 6 A schematic diagram of a transducer array element of an ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer for this application;

[0042] Figure 7 This is a stereogram of a single-layer array of a two-dimensional array transducer for ultrasound / photoacoustic dual-mode imaging in this application;

[0043] Figure 8 This is an overall schematic diagram of the ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer of this application;

[0044] Fig. 9 Schematic diagram of a single-layer array of a two-dimensional array transducer for ultrasound / photoacoustic dual-mode imaging in this application Figure 2 .

[0045] Reference numerals:

[0046] 10-ultrasonic transducer; 20-optical signal transmitting device; 30-first end; 40-limiting space;

[0047] 1-Array combination;

[0048] 11-single layer array;

[0049] 111-transducer array element; 112-circuit board; 1110-first side;

[0050] 1111- piezoelectric layer; 1112- backing layer; 1113- matching layer; 1114- electrode layer;

[0051] 11131-first matching layer; 11132-second matching layer;

[0052] 1121-Part 1; 1122-Part 2;

[0053] 11221- extension section; 11222- connection section;

[0054] 2- Fiber Optic Array;

[0055] 21- optical fiber;

[0056] 211-extension part; 212-light emitting part. DETAILED DESCRIPTION

[0057] Hereinafter, various embodiments of the present application will be described more fully. The present application may have various embodiments, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of the present application to the specific embodiments disclosed herein, but the present application should be understood to cover all adjustments, equivalents and / or alternatives within the spirit and scope of the various embodiments of the present application.

[0058] Hereinafter, the term "include" or "may include" used in various embodiments of the present application indicates the presence of a disclosed function, operation, or element, and does not limit the addition of one or more functions, operations, or elements. In addition, as used in various embodiments of the present application, the terms "include", "have", and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components, or a combination of the foregoing or the possibility of adding one or more features, numbers, steps, operations, elements, components, or a combination of the foregoing.

[0059] Example 1

[0060] like Figure 1-9 As shown, in order to solve the problem that the imaging equipment in the prior art has a single function, limited spatiotemporal resolution, and cannot obtain specific brain imaging data, this application proposes an ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer, such as Figure 1-9 As shown, it includes an ultrasonic transducer 10 and at least two optical signal transmitting devices 20, and the at least two optical signal transmitting devices 20 are arranged on the ultrasonic transducer 10; the ultrasonic transducer 10 includes at least two array combinations 1 arranged at intervals, and at least one optical signal transmitting device 20 is arranged between two adjacent array combinations 1, and the optical signal transmitting device 20 is used to transmit optical signals; the array combination 1 includes at least one single-layer array 1, and when there are multiple single-layer arrays 1, the multiple single-layer arrays 1 are distributed along the first direction a1; each single-layer array 1 includes a circuit board 112 and multiple transducer array elements 111, and the multiple transducer array elements 111 are arranged on the circuit board 112 and distributed along the second direction a2, and at least one transducer array element 111 is used to transmit ultrasonic signals; the ultrasonic transducer 10 is configured to receive ultrasonic echo signals corresponding to ultrasonic signals and photoacoustic echo signals corresponding to optical signals, so as to process imaging based on the ultrasonic echo signals and the photoacoustic echo signals.

[0061] First, the present application provides an optical signal emitting device 20 on the ultrasonic transducer 10, so that at least one optical signal emitting device 20 is provided on every two array combinations 1, so as to combine the photoacoustic imaging of the optical signal emitting device 20 and the ultrasonic imaging of the ultrasonic transducer 10, thereby having the advantages of high spatial resolution of optical imaging and strong penetration of ultrasonic imaging. At the same time, at least two array combinations 1 are arranged at intervals to form the ultrasonic transducer 10 into a planar array transducer, thereby improving the resolution and efficiency of detection compared with the existing linear array transducer.

[0062] Furthermore, considering that the size of the transducer must be ensured while the optical device and the ultrasonic device are provided on the transducer, there is a certain difficulty in processing and preparation. Based on this, the present application also makes a special design for each array combination 1, and divides the array combination 1 into at least one single-layer array 1. Each single-layer array 1 is composed of a plurality of transducer array elements 111 distributed along the second direction a2 and a circuit board 112 connected to the transducer array. The array combination 1 under this setting has a plurality of independent single-layer arrays 1. The circuit board 112 on each single-layer array 1 can not only transmit electrical signals to the transducer array element 111 on the circuit board 112 independently, but also play a certain insulating role. The array combination 1 under this setting not only reduces the difficulty of processing, but also makes the structure of the array combination 1 more stable and reliable.

[0063] Furthermore, the present application uses the ultrasonic transducer 10 to receive the ultrasonic echo signal generated after the transducer array element 111 transmits the ultrasonic signal to the target tissue, and receives the photoacoustic echo signal generated after the optical signal transmitting device 20 transmits the optical signal to the target tissue. Only one device is needed to receive multiple types of echo signals, thereby reducing the design of components and making the structure of the transducer more compact.

[0064] Furthermore, the ultrasonic imaging of the area array transducer composed of multiple array combinations 1 and the photoacoustic imaging of the optical signal transmitting device 20 are combined to form three-dimensional acoustic BOLD imaging. The three-dimensional acoustic BOLD imaging is different from the conventional imaging method. It utilizes the unique properties of ultrasonic microbubbles, combines wide-beam wave ultrasound with microbubbles, and breaks through the limitations of the diffraction limit of traditional imaging through algorithms to achieve three-dimensional ultrasonic high-resolution blood flow imaging of less than 30 microns; at the same time, the area array probe formed by multiple single-layer arrays 1 is used to obtain the photoacoustic signals of blood and the photoacoustic signals of deoxyhemoglobin and oxyhemoglobin, and analyze and obtain three-dimensional oxygen metabolism imaging, so that it has the advantages of high spatial resolution of optical imaging and strong penetration of ultrasonic imaging. While obtaining high-resolution tissue images, it can quantitatively analyze information such as blood oxygen saturation based on the difference in photoacoustic signals of deoxyhemoglobin and oxyhemoglobin, thereby significantly improving the imaging effect.

[0065] like Figure 1 , 2As shown, the first end 30 of the array assembly 1 and the first end 30 of the optical signal emitting device 20 are oriented toward the target tissue, and are used to emit ultrasonic signals and optical signals to the target tissue; the first ends 30 of all array assemblies 1 and the first ends 30 of all optical signal emitting devices 20 together form a plane or an arc-like surface.

[0066] In one embodiment, Figure 2 As shown, the first ends 30 of all array assemblies 1 and the first ends 30 of all optical signal transmitting devices 20 together form a plane. The transducer under the plane design is easy to prepare and can be suitable for simple application scenarios.

[0067] In another embodiment, the first ends 30 of all array assemblies 1 and the first ends 30 of all optical signal emitting devices 20 together constitute a quasi-arc surface, and the quasi-arc surface includes a plurality of planes, and the plurality of planes are connected and each of the planes has an angle. The present application makes the first ends 30 of all array assemblies 1 and the first ends 30 of all optical signal emitting devices 20 together constitute a quasi-arc surface through the special design of each array assembly 1 and each optical signal emitting device 20. The design of the quasi-arc surface can make the optical signal of the optical signal emitting device 20 better emitted to the target tissue, so as to better receive the photoacoustic echo signal generated at the target tissue, thereby improving the effect of photoacoustic and ultrasonic dual-mode imaging.

[0068] In other embodiments, the first ends 30 of all array assemblies 1 and the first ends 30 of all optical signal emitting devices 20 together form an arc surface, and the curvature of the arc surface is between 2 / Π-4 / Π, such as Figure 1 As shown, the dotted line is a schematic diagram of the arc surface in the main viewing direction, and the curvature of the arc surface in the main viewing direction is between 2 / Π-4 / Π. This curvature design can not only adapt to different application scenarios, but also enable the photoacoustic / ultrasonic dual-mode transducer to transmit optical signals more efficiently, so as to improve the effects of photoacoustic and ultrasonic dual-mode imaging.

[0069] like Fig. 9As shown, the circuit board 112 includes a flexible circuit board 112, and the first part 1121 of the flexible circuit board 112 is located on the first side 1110 of the single-layer array 1. When the array combination 1 includes multiple single-layer arrays 1, the multiple single-layer arrays 1 are distributed along the first direction a1, and adjacent single-layer arrays 1 are separated by the first part 1121 of the flexible circuit board 112; the second part 1122 of the flexible circuit board 112 is connected to the first part 1121 of the flexible circuit board 112 and extends a preset length, and the ratio between the width d2 of the second part 1122 of the flexible circuit board 112 away from the first part 1121 of the flexible circuit board 112 and the width d1 of the second part 1122 of the flexible circuit board 112 close to the first part 1121 of the flexible circuit board 112 is greater than 1, and the second part 1122 of the flexible circuit board 112 is used to lead out the leads on the flexible circuit board 112 to connect with external electrical components.

[0070] The present application adopts a flexible circuit board 112 to enable the transducer device to better adapt to various complex and compact spatial layouts, thereby improving the overall flexibility and adaptability of the device. By dividing the flexible circuit board 112 into a first part 1121 and a second part 1122, the first part 1121 of the flexible circuit board 112 is set on the first side 1110 of the single-layer array 1, so that the transducer array elements 111 of adjacent single-layer arrays 1 are separated by the first part 1121 of the flexible circuit board 112, so that the array elements on the array combination 1 are independent of each other, so as to reduce the influence of the vibration of a certain array element on other array elements, thereby effectively reducing the crosstalk interference between the array elements, and the width of the second part 1122 of the flexible circuit board 112 is specially designed, so that the second part 1122 of the flexible circuit board 112 can better disperse the leads, optimize the wiring design, better connect more electrical components, facilitate function switching, and improve the application scope of the product, thereby meeting the needs of different scenarios.

[0071] like Fig. 9 As shown, the width ratio between the width d2 of the second part 1122 of the flexible circuit board 112 away from the end of the first part 1121 of the flexible circuit board 112 and the width d1 of the second part 1122 of the flexible circuit board 112 close to the first part 1121 of the flexible circuit board 112 is between 1.2-2. The present application sets the width size of the two ends of the second part 1122 of the flexible circuit board 112 so that the second part 1122 of the flexible circuit board 112 can better disperse the leads and optimize the wiring design to better connect more electrical components.

[0072] And / or, the second portion 1122 of the flexible circuit board 112 has a connected extension section 11221 and a connecting section 11222, the length L1 of the extension section 11221 is greater than the length L2 of the connecting section 11222, and the width d2 of the connecting section 11222 away from the extension section 11221 is greater than the width d3 of the connecting section 11222 close to the extension section 11221. The present application can extend the flexible circuit board 112 to a certain extent to adapt to various complex spatial layouts, and can also distribute the leads to a certain extent to facilitate the connection between the leads and electrical components through the length setting of the second portion 1122 of the flexible circuit board 112 on the extension section 11221 and the connecting section 11222, and the width setting of the extension section 11221 and the connecting section 11222.

[0073] like Figure 1-8 As shown, the ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer also includes a substrate (not shown in the figure), the array assembly 1 is arranged on the substrate, and a limiting space 40 is defined between each adjacent array assembly 1 and the substrate. The optical signal transmitting device 20 includes a plurality of optical fibers 21, and the plurality of optical fibers 21 are arranged in the limiting space 40 and distributed along the second direction a2 to form an optical fiber 21 array 2; each optical fiber 21 includes an extension portion 211 and a light emitting portion 212, one end of the extension portion 211 passes through the substrate and extends in a direction away from the array assembly 1 for connection with an external device; the other end of the extension portion 211 is provided with a light emitting portion 212, the light emitting portion 212 is located at the first end 30 of the optical signal transmitting device 20, and the light emitting portion 212 faces the target tissue for transmitting an optical signal to the target tissue to generate a photoacoustic echo signal at the target tissue. The present application makes the spatial arrangement more reasonable by staggeredly arranging the array combination 1 and the optical signal transmitting device 20 on the substrate; at the same time, considering that the optical fiber 21 is relatively soft, a limiting space 40 is defined between the array combination 1 and the substrate, and multiple optical fibers 21 are arranged in the limiting space 40 to limit the position of the optical fiber 21 and prevent the optical fiber 21 from moving; the multiple optical fibers 21 are distributed along the second direction a2, so that the optical fiber 21 can cover a larger range of the target tissue to improve the imaging effect.

[0074] In one embodiment, Figure 1 , 2 As shown, the extension portion 211 extends and bends toward one end away from the array assembly 1 , and the arrangement can be better performed through the bent extension portion 211 , so that each extension portion 211 can be better connected to each external device.

[0075] In another embodiment, the light-emitting portion 212 of the optical fiber 21 is bent to be in an arc shape. By setting the light-emitting portion 212 of the optical fiber 21 to be in an arc shape, the reflection and scattering of light at the light-emitting portion 212 are significantly reduced, thereby reducing light loss, improving the transmission efficiency of the optical signal, and optimizing the distribution of the optical signal to make it more uniform and stable in space, thereby improving the accuracy and precision of the measurement. In addition, this design can also enhance the stability and reliability of the optical signal and reduce the attenuation and distortion of the optical signal during transmission.

[0076] like Figure 3 , 6 As shown in , 7, the transducer array element 111 includes a piezoelectric layer 1111, a backing layer 1112 and at least one matching layer 1113, at least one matching layer 1113 is arranged on one side of the piezoelectric layer 1111, and the backing layer 1112 is arranged on the other side of the piezoelectric layer 1111; the first part 1121 of the flexible circuit board 112 covers the first side 1110 of the backing layer 1112. The present application enables the flexible circuit board 112 to reliably transmit and control the signal from each transducer array element 111 through the design between the piezoelectric layer 1111, the backing layer 1112, the matching layer 1113 and the flexible circuit board 112, so as to ensure the performance and accuracy of the entire system.

[0077] like Figure 5 As shown, at least one matching layer 1113 includes a first matching layer 11131 and a second matching layer 11132, wherein the first matching layer 11131 is disposed on the piezoelectric layer 1111, and the second matching layer 11132 is disposed on the first matching layer 11131; wherein the first matching layer 11131 and the second matching layer 11132 are made of different materials and have different acoustic impedances; the first matching layer 11131 and the second matching layer 11132 cooperate with each other to optimize the acoustic impedance to obtain an optimal bandwidth and maximum acoustic energy conversion.

[0078] Specifically, the thickness of the matching layer 1113 is typically one quarter of the wavelength of the acoustic wave in the material.

[0079] For a transducer with only one layer, the acoustic impedance of the matching layer 1113 is calculated as follows:

[0080]

[0081] Z p is the acoustic impedance of the piezoelectric layer 1111, Z l It is the acoustic impedance of the medium through which sound waves propagate.

[0082] In the present application, the transducer has two matching layers 1113.

[0083] The acoustic impedance of the first matching layer 1113 is calculated as follows:

[0084]

[0085] The acoustic impedance of the second matching layer 11132 is calculated as follows:

[0086]

[0087] It can be seen that the present application achieves a smoother impedance transition, widens the frequency band, effectively reduces the reflection and energy loss of sound waves on the interface, and improves the energy transmission efficiency by setting two matching layers 1113 with different materials and different acoustic impedances. At the same time, different materials of the matching layer 1113 can meet different application requirements, such as enhancing sensitivity or improving the focusing effect of sound waves, so that the transducer can adapt to different media more flexibly and improve its performance under various conditions.

[0088] Furthermore, although ultrasound imaging can obtain the tissue structure and blood flow information of cerebral blood vessels in real time and with high resolution, photoacoustic imaging can use multi-wavelength laser to irradiate tissues, and obtain the light absorption spectrum information of tissues through photoacoustic imaging, and then quantitatively analyze the solubility of chemical components of biological tissues. Hemoglobin has two forms, oxygenated hemoglobin and deoxygenated hemoglobin, which have different absorption characteristics for electromagnetic waves of different wavelengths. Using a dual-wavelength photoacoustic imaging system to image living biological tissues, not only the total hemoglobin content in the area can be obtained, but also the relative content of oxygenated hemoglobin and deoxygenated hemoglobin can be obtained, and then the blood oxygen saturation information can be calculated, and then the arterial and venous systems can be distinguished from the photoacoustic image. Since hemoglobin is the most important oxygen carrier, it is closely related to the metabolic process of the organism. Photoacoustic imaging of hemoglobin can sensitively reflect the metabolism of the organism and the physiological function information related to it. Combining optical and ultrasonic imaging technologies can have the advantages of both optical imaging and ultrasonic imaging.

[0089] However, in the prior art, combining the ultrasonic transducer 10 and the optical fiber 21 is a technical challenge. Since the working principles of the two technologies are completely different, precise engineering design is required to achieve effective energy conversion and transmission. Therefore, there is a certain demand for the design of the optical fiber 21 and the transducer position. Secondly, energy coupling and control is also a major problem. How to effectively couple the light energy in the optical fiber 21 to the part used for ultrasonic excitation and accurately control the energy intensity of each excitation point to avoid ultrasonic intensity imbalance is the main challenge currently faced.

[0090] To this end, the present application specially designs the positions of the transducer array elements 111 and the optical fiber 21. By designing the angles and spacings between the array combination 1, and the design between the array combination 1 and the optical fiber 21 array 2, the transducer has the advantages of both high spatial resolution of optical imaging and strong penetration of ultrasonic imaging. While obtaining high-resolution tissue images, it can quantitatively analyze information such as blood oxygen saturation based on the difference in photoacoustic signals of deoxyhemoglobin and oxyhemoglobin, and has high imaging efficiency.

[0091] Specifically, Figure 1-5 As shown, the array combination 1 includes at least two single-layer arrays 1, and an adhesive is provided between each adjacent single-layer array 1, and the adjacent single-layer arrays 1 are connected by the adhesive; wherein, the number of single-layer arrays 1 in the array combination 1 is between 2 and 8. When the number of single-layer arrays 1 in the array combination 1 is one, there is an optical fiber 21 array 2 between adjacent single-layer arrays 1. By providing an optical fiber 21 array 2 every 1-8 single-layer arrays 1, the ultrasound probe formed by the array combination 1 can efficiently image to obtain clear imaging data, and the optical fiber 21 can also be better emitted to the tissue, which is convenient for subsequent processing to better obtain the blood oxygen metabolism information of the brain area, so that it has the advantages of both optical imaging space and ultrasound imaging.

[0092] Furthermore, if Figure 1-5 As shown, there is a preset angle α between two adjacent array combinations 1, and the preset angle α is between 0°-20°. At this angle, the transducer can obtain imaging data more accurately and quickly. In addition, when the preset angle α of two adjacent array combinations 1 is 0°, the multiple array combinations 1 form a planar two-dimensional array transducer. The imaging quality of the transducer under this design is high, and real-time three-dimensional ultrasonic imaging can be achieved, with higher resolution and clearer image quality. When the preset angle α of two adjacent array combinations 1 is 1°-20°, the multiple array combinations 1 form a curved two-dimensional array transducer. The curved surface design enables it to better adapt to the complex shapes of the detected objects, thereby improving the accuracy and reliability of the detection.

[0093] like Figure 6 As shown, electrode layers 1114 to 1114 are disposed between the backing layer 1112 and the piezoelectric layer 1111 and on the side of the matching layer 1113 away from the piezoelectric layer 1111 .

[0094] like Figure 1-9As shown, the height of each single-layer array 1 along the first direction a1 decreases to form a step-shaped arrangement; or the height of each single-layer array 1 decreases from the outside to the inside to form a V-shaped arrangement; or the height of each single-layer array 1 decreases from the inside to the outside to form a pyramid-shaped arrangement. Since the transducer of the present application is prepared by first preparing a single-layer array 1, and a new transducer array element 111 can be superimposed on the single-layer array 1 to form a plurality of single-layer arrays 1, or an array combination 1 can be formed by connecting a plurality of adjacent single-layer arrays 1, the entire transducer can be arranged in a variety of shapes, such as a V-shaped arrangement, a pyramid-shaped arrangement, or a step-shaped arrangement, etc., so as to meet certain special needs.

[0095] The substrate has at least two first mounting grooves (not shown in the figure) and at least two second mounting grooves (not shown in the figure), the at least two first mounting grooves and the at least two second mounting grooves are arranged alternately, the array assembly 1 is arranged in the first mounting groove, the optical fiber 21 array 2 is arranged in the second mounting groove, and the optical fiber 21 is adhered to the substrate by an adhesive. In this embodiment, the adhesive includes epoxy resin.

[0096] Example 2

[0097] like Figure 1-9 As shown, a preparation method for preparing the above-mentioned ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer comprises:

[0098] Acquire multiple circuit boards 112 and multiple transducer array elements 111, set at least two transducer array elements 111 on each circuit board 112, and the at least two transducer array elements 111 are distributed along the second direction a2, each circuit board 112 and the transducer array element 111 on the circuit board 112 constitute a single-layer array 1, and the multiple circuit boards 112 and the multiple transducer array elements 111 constitute multiple single-layer arrays 1;

[0099] A single single-layer array 1 is used as an array combination 1, or at least two single-layer arrays 1 are arranged along a first direction and bonded together to form an array combination 1;

[0100] At least two array assemblies 1 and at least two optical signal emitting devices 20 are staggered along a first direction, and two adjacent array assemblies 1 define a limiting space 40 , and the optical signal emitting devices 20 are placed in the limiting space 40 .

[0101] The present application arranges a plurality of single-layer arrays 1 first, then generates an array combination 1 by combining the plurality of single-layer arrays 1, and then staggers the array combination 1 and the optical signal emitting device 20 along a first direction, so as to limit the position of the optical signal emitting device 20 by two adjacent array combinations 1, thereby making the prepared transducer have the advantages of ultrasonic imaging of a planar array transducer and the advantages of optical imaging, and also have the advantages of stable structure and low processing difficulty.

[0102] Specifically, the plurality of transducer array elements 111 are manufactured in the following manner: first, a piezoelectric layer 1111 for manufacturing the transducer is ground flat on both sides to a preset thickness. Electrodes are sputtered on the first side of the piezoelectric layer 1111 to form an electrode layer 1114, and then the piezoelectric layer 1111 is flipped over, one or more matching layers 1113 are stacked on the second side of the piezoelectric layer 1111, and electrodes are sputtered on the matching layer 1113 to form an electrode layer 1114;

[0103] The piezoelectric layer 1111, the electrode layer 1114, and the matching layer 1113 are turned over so that the first surface of the piezoelectric layer 1111 faces upward; a backing layer 1112 is disposed on the first surface of the piezoelectric layer 1111;

[0104] A plurality of transducer array elements 111 are obtained by cutting along the stacking direction of the backing layer 1112 , the electrode layer 1114 , the piezoelectric layer 1111 , the matching layer 1113 , and the electrode layer 1114 .

[0105] In summary, the ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer and its preparation method of the present application have the following advantages:

[0106] First, the present application provides an optical signal emitting device 20 on the ultrasonic transducer 10, so that at least one optical signal emitting device 20 is provided on every two array combinations 1, so as to combine the photoacoustic imaging of the optical signal emitting device 20 and the ultrasonic imaging of the ultrasonic transducer 10, thereby having the advantages of high spatial resolution of optical imaging and strong penetration of ultrasonic imaging. At the same time, at least two array combinations 1 are arranged at intervals to form the ultrasonic transducer 10 into a planar array transducer, thereby improving the resolution and efficiency of detection compared with the existing linear array transducer.

[0107] Secondly, considering that the size of the transducer must be ensured while the optical device and the ultrasonic device are provided on the transducer, there are certain difficulties in processing and preparation. Based on this, the present application also makes a special design for each array combination 1, and divides the array combination 1 into at least one single-layer array 1. Each single-layer array 1 is composed of a plurality of transducer array elements 111 distributed along the second direction a2 and a circuit board 112 connected to the transducer array. The array combination 1 under this setting has a plurality of independent single-layer arrays 1. The circuit board 112 on each single-layer array 1 can not only transmit electrical signals to the transducer array element 111 on the circuit board 112 separately, but also play a certain insulating role. The array combination 1 under this setting not only reduces the difficulty of processing, provides a richer arrangement method, but also makes the structure of the array combination 1 more stable and reliable.

[0108] Furthermore, the present application uses the ultrasonic transducer 10 to receive the ultrasonic echo signal generated after the transducer array element 111 transmits the ultrasonic signal to the target tissue, and to receive the photoacoustic echo signal generated after the optical signal transmitting device 20 transmits the optical signal to the target tissue. Only one device is needed to receive multiple types of echo signals, thereby reducing the design of components and making the structure of the transducer more compact.

[0109] Furthermore, the ultrasonic imaging of the area array transducer composed of multiple array combinations 1 and the photoacoustic imaging of the optical signal transmitting device 20 are combined to form three-dimensional acoustic BOLD imaging. The three-dimensional acoustic BOLD imaging is different from the conventional imaging method. It utilizes the unique properties of ultrasonic microbubbles, combines wide-beam wave ultrasound with microbubbles, and breaks through the limitations of the diffraction limit of traditional imaging through algorithms to achieve three-dimensional ultrasonic high-resolution blood flow imaging of less than 30 microns; at the same time, the area array probe formed by multiple single-layer arrays 1 is used to obtain the photoacoustic signals of blood and the photoacoustic signals of deoxyhemoglobin and oxyhemoglobin, and analyze and obtain three-dimensional oxygen metabolism imaging, so that it has the advantages of high spatial resolution of optical imaging and strong penetration of ultrasonic imaging. While obtaining high-resolution tissue images, it can quantitatively analyze information such as blood oxygen saturation based on the difference in photoacoustic signals of deoxyhemoglobin and oxyhemoglobin, thereby significantly improving the imaging effect.

[0110] In various embodiments of the present application, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the words listed at the same time. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0111] The expressions (such as "first", "second", etc.) used in the various embodiments of the present application may modify the various constituent elements in the various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing one element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of the present application, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0112] It should be noted that in this application, unless otherwise clearly specified and defined, the terms "installation", "connection", "fixation" and the like 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 an indirect connection through an intermediate medium; it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0113] In the present application, a person of ordinary skill in the art should understand that the terms indicating orientation or positional relationship herein are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0114] The terms used in the various embodiments of the application are only used to describe the purpose of specific embodiments and are not intended to limit the various embodiments of the application. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as the meanings commonly understood by ordinary technicians in the field of the various embodiments of the application. The terms (such as the terms defined in the dictionary generally used) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly defined in the various embodiments of the application.

Claims

1. An ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer, characterized in that: It comprises an ultrasonic transducer and at least two optical signal emitting devices, wherein at least two of the optical signal emitting devices are arranged on the ultrasonic transducer; The ultrasonic transducer comprises at least two array combinations arranged at intervals, at least one optical signal emitting device is arranged between two adjacent array combinations, and the optical signal emitting device is used to emit an optical signal; The array combination includes at least one single-layer array, and when there are multiple single-layer arrays, the multiple single-layer arrays are distributed along a first direction; each of the single-layer arrays includes a circuit board and multiple transducer array elements, the multiple transducer array elements are arranged on the circuit board and distributed along a second direction, and at least one transducer array element is used to transmit an ultrasonic signal; the ultrasonic transducer is configured to receive an ultrasonic echo signal corresponding to the ultrasonic signal and a photoacoustic echo signal corresponding to the optical signal, so as to process imaging based on the ultrasonic echo signal and the photoacoustic echo signal.

2. The ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer according to claim 1, characterized in that: The first end of the array assembly and the first end of the optical signal emitting device are directed toward the target tissue, and are used to emit an ultrasonic signal and an optical signal to the target tissue; The first ends of all the array combinations and the first ends of all the optical signal emitting devices together form a plane, an arc surface or an arc-like surface.

3. The ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer according to claim 1, characterized in that: The circuit board comprises a flexible circuit board, a first portion of the flexible circuit board is located at a first side of the single-layer array, and when the array combination comprises a plurality of the single-layer arrays, the plurality of the single-layer arrays are distributed along the first direction, and the transducer array elements of adjacent single-layer arrays are spaced apart by the first portion of the flexible circuit board; The second part of the flexible circuit board is connected to the first part of the flexible circuit board and extends a preset length, and the width ratio between an end of the second part of the flexible circuit board away from the first part of the flexible circuit board and an end of the second part of the flexible circuit board close to the first part of the flexible circuit board is greater than 1, and the second part of the flexible circuit board is used to lead out the leads on the flexible circuit board to connect with external electrical components.

4. The ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer according to claim 3, characterized in that: A width ratio between an end of the second part of the flexible circuit board away from the first part of the flexible circuit board and an end of the second part of the flexible circuit board close to the first part of the flexible circuit board is between 1.2 and 2; And / or, the second part of the flexible circuit board has a connected extension section and a connecting section, the length of the extension section is greater than the length of the connecting section, and the width of the connecting section away from the extension section is greater than the width of the connecting section close to the extension section.

5. The ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer according to claim 1, characterized in that: It also includes a substrate, the array assembly is arranged on the substrate, and a limiting space is defined between each adjacent array assembly and the substrate. The optical signal transmitting device comprises a plurality of optical fibers, the plurality of optical fibers are arranged in the limiting space and distributed along the second direction to form an optical fiber array; Each of the optical fibers includes an extension portion and a light emitting portion, wherein one end of the extension portion passes through the substrate and extends in a direction away from the array combination for connection with an external device; the other end of the extension portion is provided with the light emitting portion, the light emitting portion is located at the first end of the optical signal emitting device, and the light emitting portion faces the target tissue.

6. The ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer according to claim 3, characterized in that: The transducer array element comprises a piezoelectric layer, a backing layer and at least one matching layer, wherein at least one matching layer is arranged on one side of the piezoelectric layer, the backing layer is arranged on the other side of the piezoelectric layer, and the first part of the flexible circuit board covers the first side of the backing layer; At least one of the matching layers includes a first matching layer and a second matching layer, the first matching layer is arranged on the piezoelectric layer, and the second matching layer is arranged on the first matching layer, the first matching layer and the second matching layer are made of different materials and have different acoustic impedances; the first matching layer and the second matching layer work together to optimize the acoustic impedance to obtain optimal bandwidth and maximum acoustic energy conversion.

7. The ultrasound / photoacoustic dual-mode imaging two-dimensional array transducer according to claim 1, characterized in that: The array combination includes at least two single-layer arrays, and an adhesive is provided between each adjacent single-layer array, and the adjacent single-layer arrays are connected by the adhesive; wherein the number of the single-layer arrays in the array combination is between 2 and 8; And / or, there is a preset angle between two adjacent array combinations, and the preset angle is between 0° and 20°.

8. The ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer according to claim 6, characterized in that: Electrode layers are disposed between the backing layer and the piezoelectric layer and on a side of the matching layer away from the piezoelectric layer.

9. The ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer according to claim 1, characterized in that: The height of each single-layer array along the first direction decreases gradually to form a step-shaped arrangement; or the height of each single-layer array decreases from the outside to the inside to form a V-shaped arrangement; or the height of each single-layer array decreases from the inside to the outside to form a pyramid-shaped arrangement.

10. A preparation method for preparing the ultrasonic / photoacoustic dual-mode imaging two-dimensional array transducer according to any one of claims 1 to 9, characterized in that: include: Acquire a plurality of the circuit boards and a plurality of the transducer array elements, arrange at least two of the transducer array elements on each of the circuit boards, and at least two of the transducer array elements are distributed along the second direction, each of the circuit boards and the transducer array elements on the circuit boards constitute the single-layer array, and a plurality of the circuit boards and the plurality of the transducer array elements constitute a plurality of the single-layer arrays; Combining a single single-layer array as an array or arranging at least two single-layer arrays along the first direction and bonding them together as an array; At least two of the array combinations and at least two of the optical signal emitting devices are staggered along a first direction, two adjacent array combinations define a limiting space, and the optical signal emitting device is placed in the limiting space.

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