Ultrasonic transducer and method of manufacturing the same

Abstract

This application relates to the field of ultrasonic imaging technology, and provides an ultrasonic transducer and its fabrication method. The ultrasonic transducer includes a substrate layer, a piezoelectric layer, and an acoustic matching layer stacked sequentially along the thickness direction. The piezoelectric layer includes a substrate, which includes a wiring area and multiple piezoelectric elements spaced in a row-column pattern along both row and column directions. Adjacent piezoelectric elements are bonded together with an insulating adhesive. The upper and lower surfaces of the piezoelectric elements and the insulating adhesive are formed by vacuum-deposited electrode layers, creating rows and columns of strip electrodes. These strip electrodes can be formed by cutting and photolithography. The end of a first electrode layer is electrically connected to a first conductive element; the end of a second electrode layer is electrically connected to a second conductive element. The substrate layer and the acoustic matching layer can directly contact the piezoelectric layer for acoustic matching, improving the acoustic matching effect between the piezoelectric elements and the substrate layer and acoustic matching layer.

Description

Technical Field

[0001] This application relates to the field of ultrasonic imaging technology, and in particular to an ultrasonic transducer and its fabrication method. Background Technology

[0002] With the continuous development of ultrasound imaging technology, ultrasound imaging systems are increasingly used in medical diagnosis. Real-time three-dimensional ultrasound imaging technology is one of the important means of medical imaging diagnosis today. This technology can improve the scanning frame rate and achieve high-quality imaging requirements. Compared with traditional single-element and one-dimensional array ultrasound transducers, two-dimensional array phased array systems are an effective means of solving real-time three-dimensional ultrasound imaging. It can focus in two directions, greatly improving the detection spatial resolution.

[0003] The key component of ultrasound imaging equipment for three-dimensional ultrasound imaging is the two-dimensional array ultrasound transducer. This is because the two-dimensional array ultrasound transducer (i.e., the phased array system of the two-dimensional array) can focus in two directions, has high detection spatial resolution, and the data acquisition process is fast and stable. It can freely deflect and focus to achieve three-dimensional imaging without moving or rotating. If time is included in another dimension, four-dimensional images can be generated.

[0004] Two-dimensional array ultrasonic transducers consist of a large number of array elements arranged in rows and columns. Each element is small in size and requires independent wiring. Acoustic matching substrates and acoustic matching layers are located on both sides of each element. However, in existing ultrasonic transducers, the acoustic matching effect between the array elements and the substrates and acoustic matching layers needs improvement. Summary of the Invention

[0005] The purpose of this application is to provide an ultrasonic transducer and its manufacturing method, aiming to solve the technical problem that the acoustic matching effect of existing ultrasonic transducers needs to be improved.

[0006] In a first aspect, this application provides an ultrasonic transducer comprising a substrate layer, a piezoelectric layer, and an acoustic matching layer sequentially stacked along the thickness direction; the piezoelectric layer includes a substrate, the substrate including a wiring area and a plurality of piezoelectric elements spaced in a row-column pattern along the row and column directions, adjacent piezoelectric elements being bonded together by an insulating adhesive, and the wiring area being connected to the outside of the plurality of piezoelectric elements; a plurality of first electrode layers spaced along the row direction are disposed on the side of the substrate near the substrate layer, each first electrode layer covering one column of the piezoelectric elements; a plurality of second electrode layers spaced along the column direction are disposed on the side of the substrate near the acoustic matching layer, each second electrode layer covering one row of the piezoelectric elements; the thickness direction is perpendicular to the row direction and the column direction, respectively.

[0007] The first electrode layer extends to the wiring area at least at one end in the column direction and is electrically connected to a first conductive element in the wiring area; the second electrode layer extends to the wiring area at least at one end in the row direction and is electrically connected to a second conductive element in the wiring area.

[0008] In one embodiment, the first electrode layer extends to the wiring area at both ends in the column direction and is alternately connected with the first conductive element.

[0009] In one embodiment, the second electrode layer extends to the wiring area at both ends in the row direction and is alternately connected with the second conductive element.

[0010] In one embodiment, the first electrode layer extends to the wiring area for a length of 1 mm to 3 mm.

[0011] In one embodiment, the second electrode layer extends to the wiring area for a length of 1 mm to 3 mm.

[0012] In one embodiment, the first electrode layer and / or the second electrode layer includes an adhesion-enhancing layer, a main conductive layer, and an antioxidant layer sequentially stacked on the substrate along the thickness direction.

[0013] In one embodiment, the adhesive layer is made of at least one of chromium, titanium, aluminum, nickel, and tin.

[0014] In one embodiment, the material of the main conductive layer is at least one of copper, silver, and platinum.

[0015] In one embodiment, the material of the antioxidant layer includes at least one of gold, aluminum, iron, niobium, zirconium, and stainless steel.

[0016] In one embodiment, the thickness of the adhesion-enhancing layer is 20 nm to 30 nm.

[0017] In one embodiment, the thickness of the main conductive layer is 500 nm to 3000 nm.

[0018] In one embodiment, the thickness of the antioxidant layer is 50 nm to 100 nm.

[0019] In one embodiment, the thickness of the first electrode layer is less than or equal to 10 μm.

[0020] In one embodiment, the thickness of the second electrode layer is less than or equal to 10 μm.

[0021] In one embodiment, the material of the piezoelectric element is lead magnesium titanate single crystal, lead barium barium yttrium zirconium titanate single crystal, beryllium zirconium titanate single crystal, sodium niobium phosphate single crystal, or lithium niobate single crystal, and the material of the insulating adhesive is at least one of epoxy resin, polyurethane, polyimide, and polysulfone.

[0022] In one embodiment, both ends of the substrate in the column direction are exposed to the piezoelectric layer.

[0023] In one embodiment, both ends of the substrate in the row direction are exposed to the acoustic matching layer.

[0024] In one embodiment, the thickness of the substrate is 50 μm to 1500 μm.

[0025] In one embodiment, the acoustic matching layer includes a first matching layer and a second matching layer sequentially disposed on the piezoelectric layer along the thickness direction. The acoustic impedance of the piezoelectric array element is 25 MRayl to 35 MRayl. The acoustic impedance of the first matching layer is less than 20 MRayl and greater than the acoustic impedance of the second matching layer. The acoustic impedance of the second matching layer is greater than 2 MRayl.

[0026] In one embodiment, the first matching layer is made of a mixture of alumina powder and epoxy resin.

[0027] In one embodiment, the material of the second matching layer is epoxy resin.

[0028] In one embodiment, the thickness of the first matching layer is 90 μm to 110 μm.

[0029] In one embodiment, the thickness of the second matching layer is 50 μm to 70 μm.

[0030] In one embodiment, the center frequency of the ultrasonic transducer is 1MHz-30MHz.

[0031] In one embodiment, the thickness of the substrate layer is 3 mm to 6 mm.

[0032] Secondly, this application provides a method for manufacturing an ultrasonic transducer, the method comprising the following steps:

[0033] S100: The substrate is cut into multiple piezoelectric array elements arranged in a row and column direction respectively, and insulating adhesive is filled in the gap between two adjacent piezoelectric array elements, and wiring areas are connected to the outside of the multiple piezoelectric array elements.

[0034] S200: A plurality of first electrode layers and a plurality of second electrode layers are deposited on both sides of the substrate along the thickness direction, each first electrode layer covering a column of the piezoelectric array elements, and each second electrode layer covering a row of the piezoelectric array elements;

[0035] S300: Electrically connect the first conductive element to at least one end of the first electrode layer extending to the wiring area, and cover the first electrode layer with the substrate layer;

[0036] S400: The second conductive element is electrically connected to at least one end of the second electrode layer extending to the wiring area, and the acoustic matching layer covers the second electrode layer, wherein the second conductive element and the acoustic matching layer are offset from each other on the plane of the second electrode layer.

[0037] In one embodiment, step S100 includes the following steps:

[0038] S101: Polish the substrate;

[0039] S102: Polish the substrate after grinding;

[0040] S103: Cut the substrate along the row direction;

[0041] S104: Fill the cuts formed by cutting the substrate along the row direction with an insulating adhesive with a viscosity of 80 cPs-100 cPs, and cure the insulating adhesive.

[0042] S105: Cut the substrate along the column direction;

[0043] S106: Fill the cuts formed by cutting the substrate along the column direction with the insulating adhesive having a viscosity of 80 cPs-100 cPs, and cure the insulating adhesive.

[0044] S107: Grind the substrate to remove excess insulating adhesive.

[0045] In one embodiment, step S200 includes the following steps:

[0046] S201: An adhesion-enhancing layer, a main conductive layer, and an anti-oxidation layer are sequentially sputtered and deposited on both sides of the substrate, so that the first electrode layer and the second electrode layer are formed on both sides of the substrate, respectively.

[0047] S202: Cut the first electrode layer along the row direction and fill the cut with the insulating adhesive;

[0048] S203: Cut the second electrode layer along the column direction and fill the cut with the insulating adhesive.

[0049] In one embodiment, the step of electrically connecting the first conductive element to at least one end of the first electrode layer specifically includes:

[0050] S301: The first conductive element is alternately connected to both ends of the first electrode layer;

[0051] S302: The end of the first conductive element is fixed to the first electrode layer using the insulating adhesive;

[0052] S303: Compress the pads of the first conductive element and connect the pads of the first conductive element to the end of the first electrode layer.

[0053] The beneficial effects of the ultrasonic transducer and its fabrication method provided in this application are as follows: at least one end of the first electrode layer is exposed in the region of the piezoelectric array element and is used for electrical connection with the first conductive element. The first conductive element is not disposed in the region of the piezoelectric array element, so that the piezoelectric layer and the substrate layer can directly contact each other for acoustic matching; at least one end of the second electrode layer is exposed in the region of the piezoelectric array element and is used for electrical connection with the second conductive element. The second conductive element is not disposed between the second electrode layer and the acoustic matching layer, so that the piezoelectric layer and the acoustic matching layer can directly contact each other for acoustic matching. Therefore, the acoustic matching effect between the piezoelectric array element and the substrate layer and the acoustic matching layer is improved. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a schematic diagram of the structure of the ultrasonic transducer provided in the embodiments of this application;

[0056] Figure 2 for Figure 1 Enlarged view of point A in the image;

[0057] Figure 3 This is a schematic diagram of the substrate of the ultrasonic transducer provided in this embodiment;

[0058] Figure 4 This is another perspective view of the ultrasonic transducer provided in this embodiment;

[0059] Figure 5 for Figure 4 A sectional view;

[0060] Figure 6 for Figure 5 A magnified view of a portion of the image;

[0061] Figure 7 This is another perspective view of the ultrasonic transducer provided in this embodiment;

[0062] Figure 8 for Figure 7 Enlarged view of point B in the image;

[0063] Figure 9 This is another perspective view of the ultrasonic transducer provided in this embodiment;

[0064] Figure 10 for Figure 9 A sectional view;

[0065] Figure 11 for Figure 10 A magnified view of a portion of the image;

[0066] Figure 12 This is a test diagram of the electromechanical coefficients of the ultrasonic transducer provided in this embodiment;

[0067] Figure 13 This is a diagram showing the relationship between the pulse echo signal and the spectrum of the ultrasonic transducer provided in this embodiment;

[0068] Figure 14 This is a schematic flowchart illustrating the fabrication method of the ultrasonic transducer provided in this embodiment.

[0069] The following are the labeling elements in the figure:

[0070] X: Row direction; Y: Column direction; Z: Thickness direction;

[0071] 10. Piezoelectric layer; 11. Substrate; 111. Piezoelectric element; 112. Insulating adhesive; 113. Wiring area; 114. Support; 12. First electrode layer; 13. Second electrode layer; 14. Adhesive layer; 15. Main conductive layer; 16. Antioxidant layer;

[0072] 20. Substrate layer;

[0073] 30. Sound matching layer; 31. First matching layer; 32. Second matching layer;

[0074] 40. First conductive element; 41. First insulating plate; 42. First conductive circuit;

[0075] 50. Second conductive component; 51. Second insulating plate; 52. Second conductive line. Detailed Implementation

[0076] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0077] Throughout this specification, references to "an embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Therefore, the phrases "in one embodiment" or "in some embodiments" appear in various places throughout the specification, and not all refer to the same embodiment. Furthermore, in one or more embodiments, particular features, structures, or characteristics may be combined in any suitable manner.

[0078] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0079] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0080] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0081] Example 1

[0082] refer to Figure 1 and Figure 2The ultrasonic transducer provided in this application has a row direction X, a column direction Y, and a thickness direction Z, with the thickness direction Z perpendicular to both the row direction X and the column direction Y. Specifically, the angle between the row direction X and the column direction Y is 10° to 170°. Optionally, the row direction X is the length direction of the ultrasonic transducer, and the column direction Y is the width direction of the ultrasonic transducer; or, the row direction X is the width direction of the ultrasonic transducer, and the column direction Y is the length direction of the ultrasonic transducer; or, the row direction X and the column direction Y are neither the length direction nor the width direction of the ultrasonic transducer. The ultrasonic transducer includes a substrate layer 20, a piezoelectric layer 10, and an acoustic matching layer 30 sequentially stacked along the thickness direction Z. Figure 3 The piezoelectric layer 10 includes a substrate 11, which includes a wiring area 113 and a plurality of piezoelectric elements 111 arranged in a row-column pattern along the row direction X and the column direction Y. In other words, the plurality of piezoelectric elements 111 includes multiple rows of piezoelectric elements 111, which are spaced apart along the column direction Y, with multiple piezoelectric elements 111 in each row arranged sequentially at intervals along the row direction X; or, the plurality of piezoelectric elements 111 includes multiple columns of piezoelectric elements 111, which are spaced apart along the row direction X, with multiple piezoelectric elements 111 in each column arranged sequentially at intervals along the column direction Y. Adjacent piezoelectric elements 111 are bonded together by an insulating adhesive 112, meaning that adjacent piezoelectric elements 111 are insulated from each other, and the insulating adhesive 112 connects the plurality of piezoelectric elements 111 into a single unit. Wiring area 113 is connected to the outside of multiple piezoelectric elements 111. Multiple piezoelectric elements 111 enclose an element region, and the edges of the multiple piezoelectric elements 111 (refer to...) Figure 3 The area outside the dashed line (in the diagram) is the wiring area 113. On the side of the substrate 11 near the substrate layer 20, a plurality of first electrode layers 12 are spaced apart along the row direction X. Each first electrode layer 12 covers a column of piezoelectric elements 111, meaning the number of first electrode layers 12 corresponds one-to-one with the number of columns M of piezoelectric elements 111. The first electrode layers 12 extend along the column direction Y, and one first electrode layer 12 contacts and conducts with one column of piezoelectric elements 111. On the side of the substrate 11 near the acoustic matching layer 30, a plurality of second electrode layers 13 are spaced apart along the column direction Y. Each second electrode layer 13 covers a row of piezoelectric elements 111, meaning the number of second electrode layers 13 corresponds one-to-one with the number of rows N of piezoelectric elements 111. The second electrode layers 13 extend along the row direction X, and one second electrode layer 13 contacts and conducts with one row of piezoelectric elements 111.

[0083] Combination Figures 4 to 6 At least one end of the first electrode layer 12 in the column direction Y extends to the wiring area 113, and is electrically connected to the first conductive element 40 in the wiring area 113. Figures 9 to 11At least one end of the second electrode layer 13 in the row direction X extends to the wiring area 113 and is electrically connected to the second conductive element 50 in the wiring area 113.

[0084] In this embodiment, at least one end of the first electrode layer 12 extends to the wiring area 113 to facilitate electrical connection with the first conductive element 40. The first conductive element 40 is not disposed between the piezoelectric array element 111 and the substrate layer 20, allowing the piezoelectric layer 10 and the substrate layer 20 to directly contact each other for acoustic matching, thereby improving the efficiency of sound wave transmission and enhancing the clarity and quality of the ultrasonic signal. At least one end of the second electrode layer 13 extends to the wiring area 113 to facilitate electrical connection with the second conductive element 50. The second conductive element 50 is not disposed between the piezoelectric array element 111 and the acoustic matching layer 30, allowing the piezoelectric layer 10 and the acoustic matching layer 30 to directly contact each other for acoustic matching, thereby improving the efficiency of sound wave transmission, enhancing the clarity and quality of the ultrasonic signal, and improving the acoustic matching effect between the piezoelectric array element 111 and the substrate layer 20 and the acoustic matching layer 30.

[0085] The traditional wiring method for ultrasonic transducers involves connecting a wire independently to one side of each piezoelectric element 111. The total number of wiring operations is the product of the number of rows and columns (N*M), which is complex. Furthermore, the wires separate the piezoelectric element 111 from the acoustic matching layer 30, causing energy loss during sound wave transmission between the two. This may result in sound waves reflecting back and forth between the piezoelectric element 111 and the wires, or between the wires and the acoustic matching layer 30, generating unnecessary reflected waves and interference waves that interfere with the clarity and quality of the ultrasonic signal. In the ultrasonic transducer provided in this application, the first conductive element 40 and the second conductive element 50 are located on both sides of the substrate 11, providing more space for wiring operations and reducing wiring difficulty. The first conductive element 40 is electrically connected to the first electrode layer 12, and the number of wiring operations is the same as the number of columns M of the piezoelectric array element 111. The second conductive element 50 is electrically connected to the second electrode layer 13, and the number of wiring operations is the same as the number of rows N of the piezoelectric array element 111. The total number of wiring operations is the sum of the number of rows and columns (N+M), which improves wiring efficiency. Moreover, only the cross-region of the row and column electrodes of the first electrode layer 12 and the second electrode layer 13 will be excited and detected by ultrasonic vibration. The first conductive element 40 is not located between the piezoelectric array element 111 and the piezoelectric layer 10, and the second conductive element 50 is not located between the piezoelectric array element 111 and the acoustic matching layer 30. This will not affect the resonant frequency, frequency response and stability of the ultrasonic transducer, and will not damage the connection between the substrate layer 20 and the piezoelectric layer 10, or between the piezoelectric layer 10 and the acoustic matching layer 30, thereby improving the durability and reliability of the ultrasonic transducer.

[0086] In some embodiments, the piezoelectric element 111 is square, so that the row direction X and column direction Y are perpendicular, and the longitudinal and transverse dimensions of the piezoelectric element 111 are consistent, which facilitates cutting and filling with insulating adhesive 112, and also makes the acoustic performance consistent in both the transverse and longitudinal directions.

[0087] Specifically, the side length of the piezoelectric array element 111 is 80μm to 100μm, the spacing between adjacent piezoelectric array elements 111 is 10μm to 50μm, and the center distance between two adjacent piezoelectric array elements 111 is 100μm to 150μm. Thus, the small spacing and center distance between the adjacent piezoelectric array elements 111 provide higher spatial resolution, enabling more accurate capture of subtle details and signal changes, and providing a wide frequency response range. The small spacing also helps reduce interference and attenuation that may occur during the transmission of the received signal.

[0088] Optionally, the side length of the piezoelectric array element 111 is 80μm, 90μm or 100μm, the spacing between adjacent piezoelectric array elements 111 is 10μm, 20μm, 30μm or 50μm, and the center distance between two adjacent piezoelectric array elements 111 is 100μm, 120μm, 130μm or 150μm.

[0089] In one embodiment, the piezoelectric element 111 is made of lead magnesium niobate titanate single crystal, lead barium barium yttrium zirconium titanate single crystal, beryllium zirconium titanate single crystal, sodium niobium phosphate single crystal, or lithium niobate single crystal.

[0090] Optionally, the material of the piezoelectric element 111 is PMN-0.28PT, with a piezoelectric constant d33≥2000pC / N and an electromechanical coupling coefficient k33~0.92.

[0091] In one embodiment, an insulating adhesive 112 is used to fix the piezoelectric elements 111 and reduce crosstalk interference between adjacent piezoelectric elements 111. The insulating adhesive 112 can be made of at least one of epoxy resin, polyurethane, polyimide and polysulfone, which can not only achieve insulation between piezoelectric elements 111, but also bond to the piezoelectric elements 111.

[0092] Specifically, in combination Figure 3 The wiring area 113 can be located at one or both ends of the plurality of piezoelectric elements 111 in the row direction X, so as to support the first electrode layer 12 exposed in the plurality of piezoelectric elements 111; and the wiring area 113 can be located at one or both ends of the plurality of piezoelectric elements 111 in the column direction Y, so as to support the second electrode layer 13 exposed in the plurality of piezoelectric elements 111. Optionally, when only one end of the first electrode layer 12 in the column direction Y needs to extend to the wiring area 113, the wiring area 113 in the column direction Y can be located at one or both ends of the plurality of piezoelectric elements 111; when both ends of the first electrode layer 12 in the column direction Y need to extend to the wiring area 113, the wiring area 113 in the column direction Y is located at both ends of the plurality of piezoelectric elements 111.

[0093] In one embodiment, combined with Figure 3The wiring area 113 does not generate piezoelectric signals or actively excite mechanical vibrations. The wiring area 113 includes multiple supports 114. The supports 114 can be piezoelectric substrates, insulating ceramics, glass, or high-resistivity silicon wafers, and are not limited thereto. Adjacent supports 114 are connected by insulating adhesive 112, and the supports 114 and the array element area are connected by insulating adhesive 112. The multiple supports 114 are located at one or both ends of the array element area in the row direction X and correspond one-to-one with each row of piezoelectric array elements 111, and are located at one or both ends of the array element area in the column direction Y and correspond one-to-one with each column of piezoelectric array elements 111.

[0094] Optionally, combined Figure 3 The first, third, and fifth supports 114 on the left, from top to bottom, are connected to the first conductive line 42 of the first conductive element 40; the second, fourth, and sixth supports 114 on the right, from top to bottom, are connected to the first conductive line 42 of the first conductive element 40. The first, third, and fifth supports 114 on the upper side, from left to right, are connected to the second conductive line 52 of the second conductive element 50; the second, fourth, and sixth supports 114 on the lower side, from left to right, are connected to the second conductive line 52 of the second conductive element 50. Thus, the first conductive elements 40 are alternately connected in the column direction Y, and the second conductive elements 50 are alternately connected in the row direction X, to increase the wire spacing and reduce electrical crosstalk.

[0095] In one embodiment, the thickness of the substrate 11 is 50μm to 1500μm, which is relatively small and facilitates the miniaturization design of the ultrasonic transducer, thereby improving the applicability of the ultrasonic transducer. The corresponding probe operating frequency of the ultrasonic transducer is 1MHz to 30MHz.

[0096] Optionally, the thickness of the substrate 11 is 50μm, 150μm, 180μm, 200μm, 220μm, 500μm, 1000μm or 1500μm.

[0097] In one embodiment, the substrate 11 has a length of 20mm to 25mm and a width of 20mm to 25mm.

[0098] Optionally, the length and width of the substrate 11 are the same, both being 20mm, 22mm, 23mm or 25mm.

[0099] In some embodiments, the length of the first electrode layer 12 extending to the wiring area 113 is 1mm to 3mm. If the size of the first electrode layer 12 exposed above the plurality of piezoelectric elements 111 is too short, the electrical connection operation space between it and the first conductive element 40 is small, the connection length is short, and the connection is not strong. If the size of the first electrode layer 12 exposed above the plurality of piezoelectric elements 111 is too long, it increases the contact area between the first electrode layer 12 and the surrounding environment, making it more sensitive to external interference signals and causing interference and loss of electrical signals.

[0100] In some embodiments, the wiring area 113 is located at both ends of the plurality of piezoelectric units 111 in the column direction Y. For example, in the column direction Y, one end of the first electrode layer 12 extends to the wiring area 113 for electrical connection with the first conductive element 40. As another example, in the column direction Y, both ends of the first electrode layer 12 extend to the wiring area 113, and the first conductive element 40 can be electrically connected to either end of the first electrode layer 12, or can be alternately connected to both ends of the first electrode layer 12.

[0101] In one embodiment, combined with Figure 1 , Figures 4 to 6 The first electrode layer 12 extends to the wiring area 113 at both ends in the column direction Y and is alternately connected with the first conductive element 40 to increase the wire spacing. In other words, please combine them together. Figure 3 The left side of the first electrode layer 12 corresponding to the odd-numbered columns of piezoelectric units 111 (first, third, fifth, etc.) is connected to the first conductive element 40, while the right side of the first electrode layer 12 corresponding to the even-numbered columns of piezoelectric units 111 (second, fourth, sixth, etc.) is connected to the first conductive element 40. At the same end in the column direction Y, the interval between two adjacent electrical connection points is two row spacings. Compared to single row spacing, this increases the interval between adjacent electrical connection points, reducing electrical crosstalk, especially when the ultrasonic transducer operates at high frequencies. Simultaneously, it achieves physical separation, increases the electrical connection operation space, helps improve circuit performance and stability, and reduces potential signal interference.

[0102] Furthermore, if the interval between two adjacent electrical connection points is small, the diameter of the first conductive line 42 in the first conductive element 40 is also required to be small, which in turn increases the manufacturing cost of the ultrasonic transducer.

[0103] In some embodiments, the length of the second electrode layer 13 extending to the wiring area 113 is 1mm to 3mm. If the length of the second electrode layer 13 extending to the wiring area 113 is too short, the operating space for electrical connection with the second conductive element 50 is small, the connection length is short, and the connection is not strong. If the length of the second electrode layer 13 extending to the wiring area 113 is too long, it increases the contact area between the second electrode layer 13 and the surrounding environment, making it more sensitive to external interference signals and causing interference and loss of electrical signals.

[0104] In some embodiments, combined with Figure 7 and Figure 8 The wiring area 113 is located at both ends of the plurality of piezoelectric elements 111 in the row direction X. For example, in the row direction X, one end of the second electrode layer 13 extends to the wiring area 113 for electrical connection with the second conductive element 50. As another example, in the row direction X, both ends of the second electrode layer 13 extend to the wiring area 113, and the second conductive element 50 can be electrically connected to either end of the second electrode layer 13, or can be alternately connected to both ends of the second electrode layer 13.

[0105] In one embodiment, combined with Figure 7 , Figures 9 to 11 The second electrode layer 13 has wiring areas 113 at both ends in the row direction X, and is alternately connected with second conductive elements 50 to increase the wire spacing. At the same end in the row direction X, the spacing between two adjacent electrical connection points is two column spacings. Compared with single column spacing, this increases the wire spacing between two adjacent electrical connection points, reduces electrical crosstalk, especially when the ultrasonic transducer operates at a high frequency. It also achieves physical separation, increases the electrical connection operation space, helps improve circuit performance and stability, and reduces potential signal interference.

[0106] In one embodiment, combined with Figure 6 and Figure 11 At least one of the first electrode layer 12 and the second electrode layer 13 includes an adhesive layer 14, a main conductive layer 15, and an anti-oxidation layer 16 sequentially stacked along the thickness direction Z on the substrate 11. The adhesive layer 14 increases the connection strength between the first electrode layer 12 and / or the second electrode layer 13 and the substrate 11, reducing the possibility of the first electrode layer 12 and / or the second electrode layer 13 detaching due to mechanical vibration or external force. Especially since the piezoelectric element 111 is cut from a brittle single crystal, the adhesive layer 14 increases the flexibility of the first electrode layer 12 and / or the second electrode layer 13, facilitating stable electrical connection and preventing adjacent piezoelectric elements 111 from separating due to cracking. The main conductive layer 15 has low resistance and high conductivity, which helps in the transmission of electrical signals and the centralized distribution of electrical energy. The antioxidant layer 16 provides antioxidant protection for the main conductive layer 15, preventing the main conductive layer 15 from losing conductivity due to oxidation. At the same time, the antioxidant layer 16 can extend the service life of the first electrode layer 12 and / or the second electrode layer 13, and improve stability and reliability.

[0107] For example, combining Figure 6The first electrode layer 12 corresponds to the position of each column of piezoelectric elements 111. Each column of piezoelectric elements 111 includes multiple piezoelectric elements 111 spaced apart and insulating adhesive 112 filling the gaps. The first electrode layer 12 needs to be adhered to both the piezoelectric elements 111 and the insulating adhesive 112, resulting in interface changes. The adhesion-enhancing layer 14 can improve the adhesion between the first electrode layer 12 and the substrate 11, ensuring stable signal transmission.

[0108] Specifically, in combination Figure 6 and Figure 11 The adhesive layer 14 is made of at least one of chromium, titanium, aluminum, nickel and tin.

[0109] Specifically, the thickness of the adhesion-enhancing layer 14 is 20 nm to 30 nm. In this way, the thickness of the adhesion-enhancing layer 14 is relatively thin, which helps to reduce the thickness of the first electrode layer 12 and / or the second electrode layer 13, and avoids stress concentration between the first electrode layer 12 and / or the second electrode layer 13 and the substrate 11 due to excessive thickness.

[0110] Specifically, in combination Figure 6 and Figure 11 The main conductive layer 15 is made of at least one of copper, silver and platinum.

[0111] Specifically, the thickness of the main conductive layer 15 is 500 nm to 3000 nm. The main conductive layer 15 has the largest thickness in the electrode layer to provide lower resistance and improve conductivity, while also avoiding excessive cost and excessive spacing between the substrate 11 and the acoustic matching layer 30 or the substrate layer 20 due to a thickness exceeding 3000 nm.

[0112] Specifically, in combination Figure 6 and Figure 11 The material of the antioxidant layer 16 includes at least one of gold, aluminum, iron, niobium, zirconium and stainless steel.

[0113] Specifically, the thickness of the antioxidant layer 16 is 50 nm to 100 nm. The thickness of the antioxidant layer 16 is moderate to prevent oxides from penetrating into the main conductive layer 15. If the thickness is too thin, it may cause oxidation problems. If the thickness is too thick, it may increase manufacturing costs and increase the spacing between the substrate 11 and the acoustic matching layer 30 or the substrate layer 20.

[0114] In one embodiment, the thickness of the first electrode layer 12 is less than or equal to 10 μm. The small thickness of the first electrode layer 12 reduces the spacing between the piezoelectric element 111 and the substrate layer 20, allowing the substrate layer 20 to better eliminate interference from environmental noise on the piezoelectric element 111. Furthermore, the relatively thin first electrode layer 12 can better accommodate minute deformations between the piezoelectric element 111 and the substrate layer 20, maintain high mechanical strength, reduce stress concentration due to mismatch, lower the risk of material damage, provide a more uniform stress distribution, help reduce impedance mismatch in the acoustic wave transmission path, and improve acoustic wave transmission efficiency.

[0115] In one embodiment, the thickness of the second electrode layer 13 is less than or equal to 10 μm. The small thickness of the second electrode layer 13 reduces the gap between the piezoelectric element 111 and the acoustic matching layer 30, allowing for better sound wave transmission between them. Furthermore, the relatively thin second electrode layer 13 better accommodates minute deformations between the piezoelectric element 111 and the acoustic matching layer 30, maintains high mechanical strength, reduces stress concentration due to mismatch, lowers the risk of material damage, provides a more uniform stress distribution, helps reduce impedance mismatch in the sound wave transmission path, and improves sound wave transmission efficiency.

[0116] In some embodiments, the acoustic matching layer 30 includes a first matching layer 31 and a second matching layer 32 sequentially disposed along the thickness direction Z of the piezoelectric layer 10. The acoustic impedance of the piezoelectric element 111 is 25 MRayl to 35 MRayl. The acoustic impedance of the first matching layer 31 is less than 20 MRayl and greater than that of the second matching layer 32, and the acoustic impedance of the second matching layer 32 is greater than 2 MRayl. Through the gradual transition between the two matching layers, acoustic impedance matching between the piezoelectric element 111 and the load medium (human body) is achieved, thereby reducing sound wave loss due to reflection and transmission and improving the sound energy transmission efficiency. Optionally, the acoustic impedance of the second matching layer 32 is less than 15 MRayl.

[0117] In one embodiment, it is assumed that the acoustic impedances of the piezoelectric array element 111, the load matrix, the first matching layer 31, and the second matching layer 32 are Z, respectively. p Z l Z1 and Z2 then satisfy the following requirements: In this way, acoustic impedance matching can be achieved between the piezoelectric element 111 and the load matrix, reducing acoustic wave loss due to reflection and transmission, and improving the transmission efficiency of acoustic energy.

[0118] Optionally, when the loading matrix is ​​a human organ, Z lThe acoustic impedance Z1 of the first matching layer 31 is 1.65 MRayl, and the range of the acoustic impedance Z1 is 6 MRayl to 12 MRayl. The range of the acoustic impedance Z2 of the second matching layer 32 is 2 MRayl to 4 MRayl.

[0119] Specifically, the first matching layer 31 is made of a mixture of alumina powder and epoxy resin. Optionally, it is manufactured using a high-compression (50–70 MPa) method to increase the acoustic impedance and reduce attenuation. For example, the acoustic impedance can be increased from 5.6 MRayl to 8.54 MRayl, which is similar to the acoustic impedance of heavy metals, but with much lower attenuation. The alumina powder has a diameter of 1–2 μm, much smaller than the wavelength of sound waves, thus minimizing scattering effects and reducing attenuation at the design center frequency.

[0120] Optionally, the ratio of alumina powder to epoxy resin is 2:1.

[0121] Specifically, the material of the second matching layer 32 is epoxy resin.

[0122] Optionally, the material of the second matching layer 32 is epoxy resin 301.

[0123] Specifically, the thickness of the first matching layer 31 is 90 μm to 110 μm. Optionally, the thickness of the first matching layer 31 is 90 μm, 95 μm, 100 μm, 105 μm or 110 μm.

[0124] Specifically, the thickness of the second matching layer 32 is 50 μm to 70 μm. Optionally, the thickness of the second matching layer 32 is 50 μm, 55 μm, 60 μm, 65 μm or 70 μm.

[0125] In some embodiments, the acoustic matching layer 30 covers a plurality of piezoelectric elements 111 but does not cover the wiring area 113. It will be understood that in other embodiments, the acoustic matching layer 30 covers the entire substrate 10, with a step at the end in the row direction Y for accommodating a second conductive element 50 located on the wiring area 113.

[0126] In some embodiments, the substrate 20 can absorb unwanted acoustic waves from the back of the piezoelectric array element 111 when the ultrasonic transducer is in operation, greatly improving the quality of the two-dimensional array ultrasonic transducer.

[0127] Optionally, the acoustic impedance of the substrate 20 is 5 MRayl to 10 MRayl.

[0128] Specifically, the substrate layer 20 is an insulating substrate structure, and its preparation material can be a common material. For example, a common material can be a mixture of low-viscosity epoxy resin and tungsten powder. In other embodiments, the preparation material of the substrate layer 20 can also be other common materials. For example, a common material can be a mixture of low-viscosity epoxy resin and bismuth oxide. Other common materials can also be used; this application does not limit this, and the choice depends on the specific circumstances. It should be noted that the difference between the two preparation materials mentioned above lies in their different absorption capabilities of sound wave energy. Optionally, the substrate layer 20 is a mixture of Al2O3 powder and epoxy resin 301, which can provide acoustic attenuation over a wide frequency range.

[0129] Specifically, the thickness of the substrate layer 20 is 3mm to 10mm. A larger substrate layer 20 results in a larger volume, but better absorption of residual waves. Conversely, a smaller substrate layer 20 results in a smaller volume, but poorer absorption of residual waves. To achieve a smaller substrate layer 20 while still meeting the current requirements for residual wave absorption, the thickness of the substrate layer 20 can be set to a range of 3mm to 10mm. For example, the thickness of the substrate layer 20 can be 3mm, 5mm, 6mm, 8mm, or 10mm.

[0130] Specifically, in combination Figure 5 and Figure 6 The substrate 20 covers the entire piezoelectric layer 10. The substrate 20 has a step at the end in the column direction Y for accommodating the first conductive element 40. Thus, the substrate 20 covers the first electrode layer 12 and the first conductive element 40 located in the wiring area 113, eliminating the influence of environmental noise on the substrate 11 or the first electrode layer 12.

[0131] In some embodiments, the first conductive element 40 includes a first insulating plate 41 and a plurality of first conductive lines 42 laid on the first insulating plate 41. The number of first conductive lines 42 is the same as the number of first electrode layers 12 and corresponds one-to-one. Thus, the plurality of first conductive lines 42 have strong overall integrity; only positioning between the first insulating plate 41 and the substrate 11 is needed to align the plurality of first conductive lines 42 and the plurality of first electrode layers 12, facilitating electrical connection operations. Optionally, the first conductive element 40 is a flexible circuit board.

[0132] In some embodiments, the second conductive element 50 includes a second insulating plate 51 and a plurality of second conductive lines 52 laid on the second insulating plate 51. The number of second conductive lines 52 is the same as the number of second electrode layers 13 and corresponds one-to-one. Thus, the plurality of second conductive lines 52 have strong overall integrity; only positioning between the second insulating plate 51 and the substrate 11 is required to align the plurality of second conductive lines 52 and the plurality of second electrode layers 13, facilitating electrical connection operations. Optionally, the second conductive element 50 is a flexible circuit board.

[0133] In some embodiments, the center frequency of the ultrasonic transducer is 1MHz-30MHz.

[0134] Optionally, the center frequency of the ultrasonic transducer is 1MHz, 4MHz, 8MHz, 10MHz, 20MHz or 30MHz.

[0135] Insertion loss testing was performed on the ultrasonic transducer provided in this embodiment. The acoustic matching layer 30 of the ultrasonic transducer was immersed in water, and the signal generator was set to generate a waveform excitation of a single-tone burst mode with an amplitude of 5 cycles at the center frequency of the ultrasonic transducer. The pulsed ultrasonic wave was reflected by a 40mm thick stainless steel block in water at a distance of 3mm from the ultrasonic transducer. The pulse echo signal (V) i ) and pulsed ultrasound (V o The insertion loss can be obtained by comparing the amplitudes of the two values ​​displayed on the oscilloscope. The insertion loss IL is 49.0 dB, which is relatively small. Furthermore, combined with... Figure 12 The substrate 11 has a thickness of 200 μm, the first matching layer 31 has a thickness of 100 μm, and the second matching layer 32 has a thickness of 66 μm. The impedance and phase diagram in row 29 was measured in air using a precision impedance analyzer. The calculated electromechanical coupling coefficient kt is 0.64, significantly higher than that of traditional transducers. Here, fs is the resonant frequency at which the conductance reaches its minimum, and fp is the parallel resonant frequency at which the resistance reaches its maximum. Figure 12 We can see that fs is 5.5MHz and fp is 6.9MHz.

[0136] Combination Figure 13 In bidirectional pulse echo measurements, an ultrasonic transducer immersed in acoustic coupling agent is individually excited by a pulse generator / receiver at a repetition frequency of 2 kHz, with the pulse generator / receiver having an energy of 4 μJ. The electrical coupling and gain of the device and signal amplifier are set to 50 Ω and 26 dB, respectively. A Fast Fourier Transform (FFT) function in the oscilloscope's mathematical functions is used to convert the time-domain signal into a frequency-domain spectrum. Figure 13(b) shows the acoustic response of a representative element located at the center (60, 60) of the transducer. The average interpeak amplitude of the pulse-echo response is 121 mV (gain 26 dB), and the -6 dB bandwidth from 4.27 MHz to 11 MHz is approximately 88% at a center frequency of 6.73 MHz.

[0137] Example 2

[0138] See Figure 14 This application provides a method for fabricating an ultrasonic transducer, the method comprising the following steps:

[0139] S100: The substrate 11 is cut into multiple piezoelectric array elements 111 arranged in a row and column pattern along the row direction X and column direction Y respectively. Insulating adhesive 112 is filled in the gap between two adjacent piezoelectric array elements 111, and wiring area 113 is connected to the outside of the multiple piezoelectric array elements 111.

[0140] S200: Multiple first electrode layers 12 and multiple second electrode layers 13 are deposited on both sides of the substrate 11 along the thickness direction Z. Each first electrode layer 12 covers a row of piezoelectric elements 111, and each second electrode layer 13 covers a row of piezoelectric elements 111.

[0141] S300: The first conductive element 40 is electrically connected to at least one end of the first electrode layer 12 extending to the wiring area 113, and the substrate layer 20 covers the first electrode layer 12.

[0142] S400: The second conductive element 50 is electrically connected to at least one end of the second electrode layer 13 extending to the wiring area 113, and the acoustic matching layer 30 is covered to the second electrode layer 13.

[0143] Steps S200, S300, and S400 can be performed sequentially or in an alternating manner. For example, the fabrication of the first electrode layer 12 in step S200 can be performed first, followed by step S300, then the fabrication of the second electrode layer 13 in step S200, and finally step S400.

[0144] In this embodiment, at least one end of the first electrode layer 12 extends to the wiring area 113 for easy electrical connection with the first conductive element 40. The first conductive element 40 is not disposed between the plurality of piezoelectric elements 111 and the substrate layer 20, allowing the piezoelectric layer 10 and the substrate layer 20 to directly contact each other for acoustic matching, thereby improving the efficiency of sound wave transmission and enhancing the clarity and quality of the ultrasonic signal. At least one end of the second electrode layer 13 extends to the wiring area 113 for easy electrical connection with the second conductive element 50. The second conductive element 50 is not disposed between the plurality of piezoelectric elements 111 and the acoustic matching layer 30, allowing the piezoelectric layer 10 and the acoustic matching layer 30 to directly contact each other for acoustic matching, thereby improving the efficiency of sound wave transmission and enhancing the clarity and quality of the ultrasonic signal. Therefore, the acoustic matching effect between the piezoelectric elements 111 and the substrate layer 20 and the acoustic matching layer 30 is improved.

[0145] In one embodiment, step S100 includes the following steps:

[0146] S101: Polish the substrate 11 to flatten its surface, which will facilitate the subsequent deposition of the first electrode layer 12 and the second electrode layer 13. Polishing also controls the thickness of the substrate 11.

[0147] S102: Polish the finished substrate 11. Optionally, polish with 4000-grit alumina.

[0148] S103: Cut the substrate 11 along the X direction. Optionally, a blade with a thickness smaller than the preset interval between adjacent piezoelectric elements 111 is used for cutting. For example, if the preset interval is 30 μm, the blade thickness is selected to be 25 μm.

[0149] S104: Fill the cuts formed by cutting the substrate 11 along the X-direction using an insulating adhesive 112 with a viscosity of 80 cPs-100 cPs, and cure the insulating adhesive 112. Optionally, the filling is performed at 23°C, and the curing time is 20 to 30 hours.

[0150] S105: Cut the substrate 11 along the column direction Y. Optionally, a blade with a thickness smaller than the preset interval between adjacent piezoelectric elements 111 is used for cutting.

[0151] S106: Fill the cuts formed along the Y-axis of the substrate 11 using an insulating adhesive 112 with a viscosity of 80 cPs-100 cPs. Optionally, the filling is performed at 23°C, and the curing time is 20 to 30 hours.

[0152] S107: Grind the substrate 11 to remove excess insulating adhesive 112. Optionally, step S107 can be performed once after steps S104 and S106.

[0153] Optionally, the support 114 of the wiring area 113 can be cut from the substrate 11. That is, multiple piezoelectric units 111 and multiple supports 114 are cut out simultaneously in steps S103 and S105, and then insulating adhesive 112 is filled between the multiple supports 114 and between the supports 114 and the piezoelectric units 111 simultaneously in steps S104 and S106 to improve production efficiency. It is understood that in other embodiments, the support 114 can also be insulating ceramic, glass, or a high-resistivity silicon wafer, and is not limited here.

[0154] In one embodiment, step S200 includes the following steps:

[0155] S201: An adhesion-enhancing layer 14, a main conductive layer 15, and an antioxidant layer 16 are sequentially sputtered and deposited on both sides of the substrate 11, thereby forming a first electrode layer 12 and a second electrode layer 13 on both sides of the substrate 11. Optionally, the first electrode layer 12 and the second electrode layer 13 are formed by magnetron sputtering.

[0156] S202: The first electrode layer 12 is cut along the column direction Y, and the cut is filled with insulating adhesive 112. Optionally, the cutting tool, cutting position, cutting parameters and step S105 are the same. It is understood that in other embodiments, photolithography can also be used to divide the first electrode layer 12 into strips.

[0157] S203: The second electrode layer 13 is cut along the X direction, and the cut is filled with insulating adhesive 112. Optionally, the cutting tool, cutting position, cutting parameters and step S103 are the same. It is understood that in other embodiments, photolithography can also be used to divide the second electrode layer 13 into strips.

[0158] In step S200, steps S201, S202, and S203 can be performed sequentially, or the first electrode layer 12 in step S201 and step S202 can be performed first, and then the second electrode layer 13 in step S201 and step S203 can be performed.

[0159] Furthermore, after step S203, the fabrication method further includes step S204: polarizing the substrate 11 for 30 minutes at room temperature under a constant electric field of 10 kV / cm. The polarized region is the element region, and the wiring region 113 is not polarized, that is, the wiring region 113 does not generate piezoelectric signals and does not actively generate mechanical vibrations.

[0160] In one embodiment, the step of electrically connecting the first conductive element 40 to at least one end of the first electrode layer 12 specifically includes:

[0161] S301: The first conductive element 40 is alternately connected to both ends of the first electrode layer 12.

[0162] S302: The end of the first conductive element 40 is fixed to the first electrode layer 12 using an insulating adhesive 112.

[0163] S303: Compress the pads of the first conductive element 40 to connect the pads of the first conductive element 40 to the end of the first electrode layer 12. Compressing the pads increases the contact area and adhesion between the pads and the first electrode layer 12, effectively reducing the presence of oxide layers or contaminants between the contact surfaces, and also reduces resistance. Optionally, after soldering, the surface is cured in an oven at 65°C for 3 hours.

[0164] Optionally, after step S303, step S304 is also included: using a multimeter to check for short circuits.

[0165] In one embodiment, the step of electrically connecting the second conductive element 50 to at least one end of the second electrode layer 13 specifically includes:

[0166] S401: The second conductive element 50 is alternately connected to both ends of the second electrode layer 13.

[0167] S402: The end of the second conductive element 50 is fixed to the second electrode layer 13 using an insulating adhesive 112.

[0168] S403: Compress the pads of the second conductive element 50 to connect the pads of the second conductive element 50 to the end of the second electrode layer 13. Compressing the pads increases the contact area and adhesion between the pads and the second electrode layer 13, effectively reducing the presence of oxide layers or contaminants between the contact surfaces, and also reduces resistance. Optionally, after soldering, the surface is cured in an oven at 65°C for 3 hours.

[0169] Optionally, after step S403, step S404 is also included: using a multimeter to check for short circuits.

[0170] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An ultrasonic transducer, characterized in that, The ultrasonic transducer includes a backing layer, a piezoelectric layer, and an acoustic matching layer stacked sequentially along the thickness direction. The piezoelectric layer includes a substrate, which includes a wiring area and a plurality of piezoelectric elements spaced in a row-column pattern along both the row and column directions. Adjacent piezoelectric elements are bonded together with an insulating adhesive. The wiring area is connected to the outside of the plurality of piezoelectric elements. A plurality of first electrode layers are disposed on the side of the substrate near the backing layer, spaced along the row direction. Each first electrode layer covers one column of piezoelectric elements. A plurality of second electrode layers are disposed on the side of the substrate near the acoustic matching layer, spaced along the column direction. Each second electrode layer covers one row of piezoelectric elements. The thickness direction is perpendicular to both the row and column directions. The first electrode layer extends at least one end in the column direction to the wiring area and is electrically connected to a first conductive element in the wiring area. The first conductive element is not disposed between the piezoelectric element and the backing layer, so that the piezoelectric layer and the backing layer are in direct contact for acoustic matching. The second electrode layer extends at least one end in the row direction to the wiring area and is electrically connected to a second conductive element in the wiring area. The second conductive element is not disposed between the piezoelectric element and the acoustic matching layer, so that the piezoelectric layer and the acoustic matching layer are in direct contact for acoustic matching. The first conductive element and the second conductive element are flexible circuit boards. The piezoelectric array element is made of PMN-0.28PT, with a piezoelectric constant d33 ≥ 2000 pC / N and an electromechanical coupling coefficient k33 ~ 0.

92. The wiring area includes multiple supports, and the wiring area does not generate piezoelectric signals.

2. The ultrasonic transducer according to claim 1, characterized in that: The first electrode layer extends to the wiring area at both ends in the column direction and is alternately connected with the first conductive element; And / or, the second electrode layer extends to the wiring area at both ends in the row direction and is alternately connected with the second conductive element.

3. The ultrasonic transducer according to claim 1, characterized in that: The length of the first electrode layer extending to the wiring area is 1mm to 3mm; And / or, the second electrode layer extends to the wiring area by a length of 1mm to 3mm.

4. The ultrasonic transducer according to claim 1, characterized in that: The first electrode layer and / or the second electrode layer include an adhesion-enhancing layer, a main conductive layer, and an antioxidant layer sequentially stacked on the substrate along the thickness direction.

5. The ultrasonic transducer according to claim 4, characterized in that: The adhesive layer is made of at least one of chromium, titanium, aluminum, nickel and tin; the main conductive layer is made of at least one of copper, silver and platinum; and the antioxidant layer is made of at least one of gold, aluminum, iron, niobium, zirconium and stainless steel.

6. The ultrasonic transducer according to claim 4, characterized in that: The thickness of the adhesion-enhancing layer is 20nm~30nm, the thickness of the main conductive layer is 500nm~3000nm, and the thickness of the antioxidant layer is 50nm~100nm.

7. The ultrasonic transducer according to claim 1, characterized in that: The insulating adhesive is made of at least one of epoxy resin, polyurethane, polyimide and polysulfone; both ends of the substrate in the row direction are exposed to the acoustic matching layer; the thickness of the substrate is 50μm to 1500μm.

8. The ultrasonic transducer according to claim 1, characterized in that: The acoustic matching layer includes a first matching layer and a second matching layer sequentially disposed on the piezoelectric layer along the thickness direction. The acoustic impedance of the piezoelectric array element is 25 MRayl to 35 MRayl. The acoustic impedance of the first matching layer is less than 20 MRayl and greater than the acoustic impedance of the second matching layer. The acoustic impedance of the second matching layer is greater than 2 MRayl.

9. The ultrasonic transducer according to claim 8, characterized in that: The acoustic matching layer also includes at least one of the following features: The first matching layer is made of a mixture of alumina powder and epoxy resin; The second matching layer is made of epoxy resin; The thickness of the first matching layer is 90μm~110μm; The thickness of the second matching layer is 50μm~70μm.

10. The ultrasonic transducer according to any one of claims 1 to 9, characterized in that: The center frequency of the ultrasonic transducer is 1 MHz-30 MHz, and the thickness of the backing layer is 3 mm to 10 mm.

11. A method for manufacturing an ultrasonic transducer as described in claim 1, characterized in that, The method includes the following steps: S100: The substrate is cut into multiple piezoelectric array elements arranged in a row and column direction respectively, and insulating adhesive is filled in the gap between two adjacent piezoelectric array elements, and wiring areas are connected to the outside of the multiple piezoelectric array elements. S200: A plurality of first electrode layers and a plurality of second electrode layers are deposited on both sides of the substrate along the thickness direction, each first electrode layer covering a column of the piezoelectric array elements, and each second electrode layer covering a row of the piezoelectric array elements; S300: The first conductive element is electrically connected to at least one end of the first electrode layer extending to the wiring area, and the backing layer covers the first electrode layer; the first conductive element is not disposed between the piezoelectric element and the backing layer, so that the piezoelectric layer and the backing layer are in direct contact for acoustic matching. S400: The second conductive element is electrically connected to at least one end of the second electrode layer extending to the wiring area, and the acoustic matching layer covers the second electrode layer; the second conductive element is not disposed between the piezoelectric element and the acoustic matching layer, so that the piezoelectric layer and the acoustic matching layer are in direct contact for acoustic matching; the first conductive element and the second conductive element are flexible circuit boards; The piezoelectric array element is made of PMN-0.28PT, with a piezoelectric constant d33 ≥ 2000 pC / N and an electromechanical coupling coefficient k33 ~ 0.

92. The wiring area includes multiple supports, and the wiring area does not generate piezoelectric signals.

12. The method for preparing an ultrasonic transducer according to claim 11, characterized in that, Step S100 includes the following steps: S101: Polish the substrate; S102: Polish the substrate after grinding; S103: Cut the substrate along the row direction; S104: Fill the cuts formed by cutting the substrate along the row direction with an insulating adhesive with a viscosity of 80 cPs-100 cPs, and cure the insulating adhesive. S105: Cut the substrate along the column direction; S106: Fill the cuts formed by cutting the substrate along the column direction with the insulating adhesive having a viscosity of 80 cPs-100 cPs, and cure the insulating adhesive. S107: Grind the substrate to remove excess insulating adhesive.

13. The method for preparing an ultrasonic transducer according to claim 11, characterized in that: Step S200 includes the following steps: S201: An adhesion-enhancing layer, a main conductive layer, and an anti-oxidation layer are sequentially sputtered and deposited on both sides of the substrate, so that the first electrode layer and the second electrode layer are formed on both sides of the substrate, respectively. S202: Cut the first electrode layer along the column direction and fill the cut with the insulating adhesive; S203: Cut the second electrode layer along the row direction and fill the cut with the insulating adhesive.

14. The method for manufacturing an ultrasonic transducer according to any one of claims 11 to 13, characterized in that, The step of electrically connecting the first conductive element to at least one end of the first electrode layer specifically includes: S301: The first conductive element is alternately connected to both ends of the first electrode layer; S302: The end of the first conductive element is fixed to the first electrode layer using the insulating adhesive; S303: Compress the pads of the first conductive element and connect the pads of the first conductive element to the end of the first electrode layer.

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