One-dimensional array ultrasonic transducer and method for manufacturing the same

Abstract

The application relates to the technical field of ultrasonic imaging, and provides a one-dimensional array type ultrasonic transducer and a preparation method thereof. The ultrasonic transducer comprises a substrate layer, a piezoelectric layer and an acoustic matching layer which are sequentially stacked in a thickness direction; the piezoelectric layer comprises a substrate, the substrate comprises an extension support and multiple rows of piezoelectric elements, two adjacent rows of piezoelectric elements are bonded through insulating adhesive, and the extension support is connected to at least one side of the multiple rows of piezoelectric elements in a row direction; the piezoelectric layer further comprises multiple first electrode layers which are arranged on one side of the substrate in the row direction and are spaced apart, each first electrode layer covers one row of piezoelectric elements; at least one end of the first electrode layer in the row direction extends to the extension support, and the first electrode layer is electrically connected to a conductive member on the extension support. The conductive member is indirectly electrically connected to the piezoelectric elements of the corresponding row through the first electrode layer, so that the piezoelectric layer, the acoustic matching layer and the substrate layer can be directly contacted for acoustic matching, and the acoustic matching effect of the piezoelectric elements and the acoustic matching layer is improved.

Description

Technical Field

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

[0002] One-dimensional array ultrasonic transducers comprise a large number of piezoelectric elements, with an acoustically matched substrate and a matching layer on either side of each element. Because each piezoelectric element is small and requires independent wiring, copper wires or flexible circuit boards are placed between the piezoelectric elements and the matching layer, or between the piezoelectric elements and the substrate, to achieve electrical connection between the ultrasonic transducer and the external environment. This allows for the conversion of electrical energy into mechanical energy and the mutual conversion of sound waves and electrical signals. However, in existing one-dimensional array ultrasonic transducers, the acoustic matching effect between the piezoelectric elements and the matching layer, or between the piezoelectric elements and the substrate, needs improvement. Summary of the Invention

[0003] The purpose of this invention is to provide a one-dimensional array ultrasonic transducer and its fabrication method, aiming to solve the technical problem that the acoustic matching effect of existing one-dimensional array ultrasonic transducers needs to be improved.

[0004] In a first aspect, this application provides a one-dimensional array 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 an extended support member and multiple rows of piezoelectric elements spaced apart along the column direction, adjacent rows of piezoelectric elements being bonded together by an insulating adhesive, the extended support member being connected to at least one side of the multiple rows of piezoelectric elements in the row direction; the piezoelectric layer further includes multiple first electrode layers spaced apart along the column direction on one side of the substrate, each first electrode layer covering one row of piezoelectric elements; the thickness direction is perpendicular to both the row direction and the column direction.

[0005] The first electrode layer extends to at least one end of the extended support in the row direction and is electrically connected to a conductive element on the extended support.

[0006] In one embodiment, the extended support is made of the same material as the piezoelectric array element, and the extended support is not polarized.

[0007] In one embodiment, the extended support is made of a different material than the piezoelectric element.

[0008] In one embodiment, the conductive element includes an insulating plate and metal wires disposed on the insulating plate. The number of metal wires is the same as the number of the first electrode layers and corresponds one-to-one. The insulating plate is connected to the extended support, and the metal wires are electrically connected to the corresponding first electrode layers.

[0009] In one embodiment, the insulating plate is a flexible plate.

[0010] In one embodiment, the conductive element is a conductive line corresponding to the first electrode layer, the first end of the conductive line is electrically connected to the corresponding first electrode layer, and the second end of the conductive line extends away from the substrate; in two adjacent conductive lines, the interval between their second ends is greater than the interval between their first ends.

[0011] In one embodiment, the conductive line includes a first straight segment and a second straight segment. The two ends of the first straight segment are respectively connected to the first electrode layer and the second straight segment. The first straight segment is set at an acute angle to the column direction and extends toward the end of the substrate in the column direction. The second straight segment is parallel to the row direction and the line width of the second straight segment is greater than the line width of the first straight segment.

[0012] In one embodiment, the one-dimensional array ultrasonic transducer further includes an insulating support located on the outside of the substrate, and the conductive element located on the outer portion of the substrate is supported by the insulating support.

[0013] In one embodiment, the first electrode layer is located on the side of the substrate near the acoustic matching layer, and the piezoelectric layer further includes a second electrode layer disposed on the side of the substrate near the substrate layer, the second electrode layer covering multiple rows of the piezoelectric elements.

[0014] In one embodiment, the extended support is connected to opposite sides of the multiple rows of piezoelectric elements in the row direction, and the first electrode layer extends to the extended support at both ends in the row direction and is alternately connected to the conductive elements.

[0015] In one embodiment, the first electrode layer includes an adhesion-enhancing layer, a main conductive layer, and an antioxidant layer sequentially stacked on the substrate along the thickness direction.

[0016] In one embodiment, the adhesive layer is made of at least one of chromium, titanium, aluminum, nickel, and tin.

[0017] In one embodiment, the material of the main conductive layer is at least one of copper, silver, and platinum.

[0018] In one embodiment, the material of the antioxidant layer includes at least one of gold, aluminum, iron, niobium, zirconium, and stainless steel.

[0019] In one embodiment, the thickness of the adhesion-enhancing layer is 20 nm to 30 nm.

[0020] In one embodiment, the thickness of the main conductive layer is 500 nm to 3000 nm.

[0021] In one embodiment, the thickness of the antioxidant layer is 50 nm to 100 nm.

[0022] In one embodiment, the thickness of the first electrode layer is less than or equal to 10 μm.

[0023] In one embodiment, the center-to-center distance between adjacent first electrode layers is 10 μm to 100 μm.

[0024] In one embodiment, the center frequency of the one-dimensional array ultrasonic transducer is greater than or equal to 15 MHz.

[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 7 MRayl and less than 15 MRayl.

[0026] Secondly, this application provides a method for fabricating a one-dimensional array ultrasonic transducer, the method comprising the following steps:

[0027] S100: The substrate is cut into multiple rows of piezoelectric array elements along the row direction, insulating adhesive is filled in the gap between two adjacent rows of piezoelectric array elements, and an extension support is connected to the outside of the multiple rows of piezoelectric array elements.

[0028] S200: A plurality of first electrode layers are deposited on one side of the substrate along the thickness direction, each first electrode layer covering a row of the piezoelectric array elements, and at least one end of the first electrode layer in the row direction extends to the extended support.

[0029] S300: Electrically connect the conductive element to at least one end of the first electrode layer extending to the extended support;

[0030] S400: Cover one side of the substrate with a substrate layer and cover the other side of the substrate with an acoustic matching layer.

[0031] The beneficial effects of the one-dimensional array ultrasonic transducer and its fabrication method provided by this invention are as follows: the extended support is located on at least one side of the multi-row piezoelectric array elements in the row direction, and is not limited by the size and spacing of the piezoelectric array elements, providing sufficient space for the conductive element and the first electrode layer to connect on the extended support; the first electrode layer extends to the extended support located outside the multi-row piezoelectric array elements, and the conductive element is indirectly electrically connected to the corresponding row of piezoelectric array elements through the first electrode layer, avoiding the problem of poor acoustic matching caused by the conductive element directly contacting the piezoelectric array elements due to being located between the acoustic matching layer and the piezoelectric array elements or between the substrate layer and the piezoelectric array elements. The piezoelectric layer and the acoustic matching layer, as well as the piezoelectric layer and the substrate layer, can directly contact each other for acoustic matching, solving the technical problem that the acoustic matching effect of existing one-dimensional array ultrasonic transducers needs to be improved, and significantly improving the performance of one-dimensional array ultrasonic transducers and ultrasonic imaging. Attached Figure Description

[0032] 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.

[0033] Figure 1 This is a schematic diagram of the structure of a one-dimensional array ultrasonic transducer provided in an embodiment of this application;

[0034] Figure 2 for Figure 1 Enlarged view of point A in the image;

[0035] Figure 3 This is a schematic diagram showing the connection between the substrate and some conductive components of the one-dimensional array ultrasonic transducer provided in this embodiment.

[0036] Figure 4 This is a top view of a one-dimensional array ultrasonic transducer provided in this embodiment;

[0037] Figure 5 This is another top view of the one-dimensional array ultrasonic transducer provided in this embodiment;

[0038] Figure 6 This is another perspective view of the one-dimensional array ultrasonic transducer provided in this embodiment;

[0039] Figure 7 for Figure 6 A sectional view;

[0040] Figure 8 for Figure 7 Enlarged view of point B;

[0041] Figure 9 This is another perspective view of the one-dimensional array ultrasonic transducer provided in this embodiment;

[0042] Figure 10 This is a schematic flowchart illustrating the fabrication method of the one-dimensional array ultrasonic transducer provided in this embodiment.

[0043] The following are the labeling elements in the figure:

[0044] X: Row direction; Y: Column direction; Z: Thickness direction;

[0045] 10. Piezoelectric layer; 11. Substrate; 111. Piezoelectric element; 112. Insulating adhesive; 113. Extended support; 12. First electrode layer; 121. Adhesive layer; 122. Main conductive layer; 123. Antioxidant layer; 13. Second electrode layer;

[0046] 20. Substrate layer;

[0047] 30. Sound matching layer; 31. First matching layer; 32. Second matching layer;

[0048] 40. Conductive component; 41. Insulating plate; 42. Metal wire; 43. Conductive wire; 431. First straight segment; 432. Second straight segment;

[0049] 50. Insulating support components. Detailed Implementation

[0050] Embodiments of the present invention are described in detail below, examples of which are illustrated 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 the present invention, and should not be construed as limiting the present invention.

[0051] 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.

[0052] In the description of this invention, 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. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0053] 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.

[0054] In this invention, unless otherwise explicitly 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 invention according to the specific circumstances.

[0055] Example 1

[0056] Combination Figures 1 to 3 The one-dimensional array ultrasonic transducer provided in this application includes a substrate layer 20, a piezoelectric layer 10, and an acoustic matching layer 30 stacked sequentially along the thickness direction Z. The piezoelectric layer 10 includes a substrate 11, which includes an extension support 113 and multiple rows of piezoelectric array elements 111 spaced apart along the column direction Y. Adjacent rows of piezoelectric array elements 111 are bonded together by an insulating adhesive 112, i.e., adjacent piezoelectric array elements 111 are insulated from each other, and the insulating adhesive 112 connects the multiple rows of piezoelectric array elements 111 into a single unit. The extension support 113 is connected to at least one side of the multiple rows of piezoelectric array elements 111 in the row direction X. The piezoelectric layer 10 also includes multiple first electrode layers 12 spaced apart along the column direction Y on one side of the substrate 11. The first electrode layers 12 can be disposed on the side of the substrate 11 near the acoustic matching layer 30 or on the side of the substrate near the substrate layer 20. Each first electrode layer 12 covers one row of piezoelectric array elements 111. That is, the number of first electrode layers 12 corresponds one-to-one with the number of rows of piezoelectric array elements 111. The first electrode layers 12 extend along the row direction X, and one first electrode layer 12 is in contact with and connected to one row of piezoelectric array elements 111.

[0057] The thickness direction Z is perpendicular to both the row direction X and the column direction Y, wherein the angle between the row direction X and the column direction Y can be 60° to 120°, and in particular, the row direction X and the column direction Y are perpendicular to each other. Optionally, the row direction X is the length direction of the substrate 11 and the column direction Y is the width direction of the substrate 11; or, the row direction X is the width direction of the substrate 11 and the column direction Y is the length direction of the substrate 11; or, the row direction X and the column direction Y are neither the length direction nor the width direction of the substrate 11.

[0058] At least one end of the first electrode layer 12 extends to the extended support 113 in the row direction X, and the conductive element 40 is electrically connected to the extended support 113. For ease of observation, Figure 3 Only two first electrode layers 12 are shown. In practice, each row of piezoelectric array elements 111 corresponds to one first electrode layer 12.

[0059] In this embodiment, the extended support 113 is located on at least one side of the multi-row piezoelectric array elements 111 in the row direction X, and is not limited by the size and spacing of the piezoelectric array elements 111, providing sufficient operating space for the conductive element 40 and the first electrode layer 12 to be connected on the extended support 113. The first electrode layer 12 extends to the extended support 113 located outside the multi-row piezoelectric array elements 111. The conductive element 40 is indirectly electrically connected to the corresponding row of piezoelectric array elements 111 through the first electrode layer 12. This avoids the conductive element 40 directly contacting the piezoelectric array elements 111 due to being located between the acoustic matching layer 30 and the piezoelectric array elements 111 or between the substrate layer 20 and the piezoelectric array elements 111, which would cause poor acoustic matching. The piezoelectric layer 10, the substrate layer 20, and the acoustic matching layer 30 can directly contact each other for acoustic matching, 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 elements 111 and the substrate layer 20 and the acoustic matching layer 30. This significantly improves the performance of the one-dimensional array ultrasonic transducer and ultrasonic imaging.

[0060] High-frequency ultrasonic transducers are of great significance for imaging human skin and the nervous system in clinical and biomedical research. Due to the complexity of electrode contacts, high-frequency ultrasonic transducers with small aperture sizes are difficult to manufacture (both phase and linear arrays). While using metal foils (e.g., Cu, Au) or flexible circuits to form direct contact with the piezoelectric array element 111 can lead to poor acoustic matching because the piezoelectric array element 111 cannot directly contact the acoustic matching layer 30 and the substrate layer 20. For high-frequency transducers, the aperture size can be as small as 1.5 mm; therefore, direct contact with the conductive element 40 on the piezoelectric array element 111 will result in poor acoustic matching problems and significantly affect the performance of the transducer and ultrasonic imaging. Thus, the one-dimensional array ultrasonic transducer provided in this application has a center frequency greater than or equal to 15 MHz, which meets the requirements for high-frequency operation.

[0061] Optionally, the center frequency of the one-dimensional array ultrasonic transducer is 15MHz, 18MHz, 20MHz, 25MHz, 30MHz or 35MHz.

[0062] In some embodiments, combined with Figure 3 The piezoelectric element 111 is rectangular, and the X-axis dimension of the piezoelectric element 111 is much larger than the Y-axis dimension.

[0063] Specifically, the Y-axis side length of the piezoelectric array element 111 is 80μm to 110μm, the X-axis side length is 100μm to 1000μm, the Y-axis spacing between adjacent piezoelectric array elements 111 is 10μm to 50μm, and the center distance between two adjacent rows of piezoelectric array elements 111 is 100μm to 150μm. Thus, the small adjacent spacing and center distance of the 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 adjacent spacing also helps reduce potential interference and attenuation during signal transmission.

[0064] Optionally, the Y-direction side length of the piezoelectric array element 111 is 80μm, 90μm or 100μm, the Y-direction spacing between adjacent piezoelectric array elements 111 is 10μm, 2μm, 30μm or 50μm, and the Y-direction center distance between two adjacent rows of piezoelectric array elements 111 is 100μm, 120μm, 130μm or 150μm.

[0065] It is understood that in other embodiments, the multiple piezoelectric elements 111 are arranged in a row-column pattern, that is, each row of piezoelectric elements 111 includes multiple piezoelectric elements 111 spaced apart along the row direction X. The piezoelectric elements 111 are a 1-3 composite structure.

[0066] 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.

[0067] 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.

[0068] In one embodiment, combined with Figure 3 The insulating adhesive 112 is used to fix the piezoelectric array elements 111 and reduce crosstalk interference between adjacent piezoelectric array elements 111. The material of the insulating adhesive 112 can be selected from at least one of epoxy resin, polyurethane, polyimide and polysulfone, which can not only achieve insulation between piezoelectric array elements 111, but also bond to the piezoelectric array elements 111.

[0069] In one embodiment, the thickness of the substrate 11 is 50 μm to 1500 μm. The relatively small thickness allows for the achievement of a low excitation voltage during corresponding polarization, and facilitates the miniaturization design of the one-dimensional array ultrasonic transducer, thereby expanding the applicability of the one-dimensional array ultrasonic transducer.

[0070] Optionally, the thickness of the substrate 11 is 50μm, 150μm, 180μm, 200μm, 220μm, 500μm, 1000μm or 1500μm.

[0071] In one embodiment, the dimension of the substrate 11 in the column direction Y is much larger than the dimension of the substrate 11 in the row direction X.

[0072] Specifically, the substrate 11 has a dimension of 20mm to 25mm in the column direction Y and a dimension of 1mm to 10mm in the row direction X.

[0073] In this embodiment, combined with Figure 3 The extended support 113 does not generate piezoelectric signals or actively induce mechanical vibrations. The extended support 113 can be a piezoelectric substrate, insulating ceramic, glass, or a high-resistivity silicon wafer, and is not limited thereto. The extended support 113 and the piezoelectric element 111 are connected by an insulating adhesive 112.

[0074] In one embodiment, combined with Figure 3 The material of the extended support 113 is the same as that of the piezoelectric array element 111, and the extended support 113 is not polarized, so the extended support 113 does not generate piezoelectric signals and does not actively excite mechanical vibration.

[0075] In one embodiment, combined with Figure 3 The material of the extended support 113 is different from that of the piezoelectric element 111, so the extended support 113 does not generate piezoelectric signals and does not actively excite mechanical vibrations. For example, the extended support 113 is a ceramic part, a plastic part, etc.

[0076] In one embodiment, combined with Figure 4 The conductive component 40 includes an insulating plate 41 and metal wires 42 disposed on the insulating plate 41. The number of metal wires 42 is the same as the number of first electrode layers 12 and corresponds one-to-one. The insulating plate 41 is connected to the extended support 113, and the metal wires 42 are electrically connected to the corresponding first electrode layers 12. Multiple metal wires 42 are disposed together on the insulating plate 41, which has strong integrity. It is only necessary to position the insulating plate 41 and the substrate 11 to achieve one-to-one alignment of multiple metal wires 42 and multiple first electrode layers 12, which facilitates electrical connection operations.

[0077] When there is one insulating plate 41, the insulating plate 41 is located on one side of the multi-row piezoelectric array elements 111 in the row direction X, and the number of metal lines 42 on the insulating plate 41 is the same as the number of the first electrode layers 12 and corresponds one-to-one. When there are two insulating plates 41, the two insulating plates 41 are located on opposite sides of the multi-row piezoelectric array elements 111 in the row direction X, and the sum of the metal lines 42 on the two insulating plates 41 is the same as the number of the first electrode layers 12 and corresponds one-to-one.

[0078] Optionally, the insulating plate 41 is a flexible plate.

[0079] In one embodiment, combined with Figure 5 The conductive element 40 consists of conductive lines 43 that correspond one-to-one with the first electrode layer 12. The first end of the conductive line 43 is electrically connected to the corresponding first electrode layer 12, and the second end of the conductive line 43 extends away from the substrate 11. In two adjacent conductive lines 43, the spacing between their second ends is greater than the spacing between their first ends, thereby allowing the second end of the conductive element 40 to have a larger operating space for connection with external circuits, simplifying the electrical connection operation.

[0080] It is understood that in other embodiments, the spacing between the second ends of two adjacent conductive lines 43 may be equal to or less than the spacing between their first ends, and no specific limitation is made here. For example, when the spacing between the first ends of two adjacent conductive lines 43 has sufficient space for connection operation, the spacing between the two adjacent conductive lines 43 remains unchanged, that is, the spacing between the second ends may be equal to the spacing between the first ends. As another example, when the spacing between the first ends of two adjacent conductive lines 43 is large, the spacing between the two adjacent conductive lines 43 gradually decreases, that is, the spacing between the second ends may be less than the spacing between the first ends, so as to reduce the size of the one-dimensional array ultrasonic transducer.

[0081] Specifically, the conductive line 43 includes a first straight segment 431 and a second straight segment 432. The two ends of the first straight segment 431 are connected to the first electrode layer 12 and the second straight segment 432, respectively. The first straight segment 431 is set at an acute angle to the column direction Y and extends towards the end of the substrate 11 in the column direction Y. The second straight segment 432 is parallel to the row direction X. In this way, the first straight segment 431 diffuses outward, increasing the spacing between the second straight segments 432 and simplifying the operation of connecting to external circuits.

[0082] Optionally, the line width of the second straight segment 432 is greater than that of the first straight segment 431, so that the second end of the conductive element 40 is more convenient to be connected to the external circuit.

[0083] In one embodiment, combined with Figure 5The one-dimensional array ultrasonic transducer also includes an insulating support 50, which is located on the outside of the substrate 11, and the conductive element 40 is located on the outside of the substrate 11 and supported by the insulating support 50.

[0084] Optionally, the insulating support 50 may be a ceramic or plastic component.

[0085] In this embodiment, combined with Figure 1 and Figure 2 The extension support 113 can be located at one or both ends of the multi-row piezoelectric array 111 in the row direction X, so as to support the first electrode layer 12 exposed in the multi-row piezoelectric array 111. Optionally, when only one end of the first electrode layer 12 needs to extend to the extension support 113 in the row direction X, the extension support 113 can be located at one or both ends of the multi-row piezoelectric array 111 in the row direction X; when both ends of the first electrode layer 12 need to extend to the extension support 113 in the row direction X, the extension support 113 is located at both ends of the multi-row piezoelectric array 111 in the row direction X.

[0086] In one embodiment, combined with Figure 5 The extended support 113 is connected to the opposite sides of the multi-row piezoelectric array elements 111 in the row direction X. The first electrode layer 12 extends to the extended support 113 at both ends in the row direction X and is alternately connected with conductive elements 40 to increase the wire spacing between adjacent conductive elements 40, reduce electrical crosstalk, especially when the operating frequency of the one-dimensional array ultrasonic transducer is high frequency. At the same time, physical separation is achieved, increasing the electrical connection operation space, which helps to improve circuit performance and stability, and reduce potential signal interference.

[0087] In other words, the left side of the first electrode layer 12 corresponding to the odd-numbered rows of piezoelectric units (first, third, fifth, etc.) is connected to the conductive element 40, while the right side of the first electrode layer 12 corresponding to the even-numbered rows of piezoelectric units (second, fourth, sixth, etc.) is connected to the conductive element 40. Furthermore, if the interval between two adjacent electrical connection points is small, the diameter of the conductive element 40 also needs to be small, thus increasing the manufacturing cost of the one-dimensional array ultrasonic transducer.

[0088] In one embodiment, combined with Figures 6 to 8The first electrode layer 12 includes an adhesive layer 121, a main conductive layer 122, and an anti-oxidation layer 123, which are sequentially stacked on the substrate 11 along the thickness direction Z. The adhesive layer 121 increases the connection strength between the first electrode layer 12 and the substrate 11, reducing the possibility of the first electrode layer 12 detaching due to mechanical vibration or external force. In particular, since the piezoelectric elements 111 are cut from brittle single crystals, the adhesive layer 121 increases the flexibility of the first electrode layer 12, which is beneficial for maintaining a stable electrical connection and also prevents adjacent piezoelectric elements 111 from separating due to cracking. The main conductive layer 122 has low resistance and high conductivity, which helps in the transmission of electrical signals and the centralized distribution of electrical energy. The anti-oxidation layer 123 provides anti-oxidation protection for the main conductive layer 122, preventing the main conductive layer 122 from losing conductivity due to oxidation. At the same time, the anti-oxidation layer 123 can extend the service life of the first electrode layer 12 and improve its stability and reliability.

[0089] For example, combining Figure 7 and Figure 8 The first electrode layer 12 corresponds to the position of each row of piezoelectric elements 111. Each row of piezoelectric elements 111 includes multiple rows of piezoelectric elements 111 spaced apart and an 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 adhesive layer 121 can improve the adhesion between the first electrode layer 12 and the substrate 11, ensuring stable signal transmission.

[0090] Specifically, the material of the tackifying layer 121 is at least one of chromium, titanium, aluminum, nickel and tin.

[0091] Specifically, the thickness of the adhesion-enhancing layer 121 is 20nm to 30nm. In this way, the thickness of the adhesion-enhancing layer 121 is relatively thin, which helps to reduce the thickness of the first electrode layer 12 and avoids stress concentration between the first electrode layer 12 and the substrate 11 due to excessive thickness.

[0092] Specifically, the main conductive layer 122 is made of at least one of copper, silver and platinum.

[0093] Specifically, the thickness of the main conductive layer 122 is 500 nm to 3000 nm. The main conductive layer 122 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 due to a thickness exceeding 3000 nm.

[0094] Specifically, the material of the antioxidant layer 123 includes at least one of gold, aluminum, iron, niobium, zirconium, and stainless steel.

[0095] Specifically, the thickness of the antioxidant layer 123 is 50nm to 100nm. The thickness of the antioxidant layer 123 is moderate to prevent oxides from penetrating into the main conductive layer 122. 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.

[0096] 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.

[0097] In one embodiment, the center-to-center distance between adjacent first electrode layers 12 is 10 μm to 100 μm.

[0098] In some embodiments, the length of the first electrode layer 12 extending to the extended support 113 is 1mm to 3mm. If the size of the first electrode layer 12 exposed above the multi-row piezoelectric array 111 is too short, the electrical connection operation space between it and the 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 multi-row piezoelectric array 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.

[0099] In one embodiment, combined with Figure 8 The first electrode layer 12 is located on the side of the substrate 11 near the acoustic matching layer 30. The piezoelectric layer 10 also includes a second electrode layer 13 disposed on the side of the substrate 11 near the substrate layer 20, and the second electrode layer 13 covers multiple rows of piezoelectric elements 111. The second electrode layer 13 can shield signals. Optionally, the second electrode layer 13 is grounded.

[0100] Optionally, the second electrode layer 13 includes an adhesive layer 121, a main conductive layer 122, and an antioxidant layer 123 sequentially stacked on the substrate 11 along the thickness direction Z.

[0101] Optionally, the thickness of the second electrode layer 13 is less than or equal to 10 μm. The smaller thickness of the second electrode layer 13 reduces the gap between the piezoelectric element 111 and the substrate layer 20, allowing for better and tighter contact between them. Furthermore, the relatively thin second electrode layer 13 can better accommodate minute deformations between the piezoelectric element 111 and the substrate layer 20, while maintaining high mechanical strength. This reduces stress concentration caused by mismatch and lowers the risk of material damage, providing a more uniform stress distribution. This helps reduce impedance mismatch in the acoustic wave transmission path and improves the transmission efficiency of the acoustic waves.

[0102] In one embodiment, combined Figure 9 The acoustic matching layer 30 includes a first matching layer 31 and a second matching layer 32 sequentially disposed along the thickness direction Z on 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. The acoustic impedance of the second matching layer 32 is greater than 7 MRayl and less than 15 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 the loss of sound waves due to reflection and transmission, and improving the transmission efficiency of sound energy.

[0103] 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.

[0104] Optionally, when the loading matrix is ​​a human organ, Z l The 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.

[0105] 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.

[0106] Optionally, the ratio of alumina powder to epoxy resin is 2:1.

[0107] Specifically, the material of the second matching layer 32 is epoxy resin.

[0108] Optionally, the material of the second matching layer 32 is epoxy resin 301.

[0109] 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.

[0110] 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.

[0111] In some embodiments, the substrate 20 can absorb unwanted acoustic waves from the back side of the piezoelectric array element 111 when the one-dimensional array ultrasonic transducer is in operation, greatly improving the quality of the one-dimensional array ultrasonic transducer.

[0112] Optionally, the acoustic impedance of the substrate 20 is 5 MRayl to 10 MRayl.

[0113] 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.

[0114] 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.

[0115] Example 2

[0116] Combination Figure 10 This application provides a method for fabricating a one-dimensional array ultrasonic transducer, the method comprising the following steps:

[0117] S100: The substrate 11 is cut into multiple rows of piezoelectric array elements 111 along the row direction X, insulating adhesive 112 is filled in the gap between two adjacent rows of piezoelectric array elements 111, and an extension support member 113 is connected to the outside of the multiple rows of piezoelectric array elements 111.

[0118] S200: A plurality of first electrode layers 12 are deposited on one side of the substrate 11 along the thickness direction Z. Each first electrode layer 12 covers a row of piezoelectric elements 111. At least one end of the first electrode layer 12 in the row direction X extends to the extended support member 113. Optionally, the first electrode layer 12 is formed on the substrate 11 by photolithography, which is beneficial to manufacturing a first electrode layer 12 with a smaller thickness.

[0119] S300: Electrically connect the conductive element 40 to at least one end of the first electrode layer 12 extending to the extended support 113.

[0120] S400: The substrate 20 covers one side of the substrate 11, and the acoustic matching layer 30 covers the other side of the substrate 11.

[0121] In this embodiment, at least one end of the first electrode layer 12 extends to the extended support member 113 to facilitate electrical connection with the conductive member 40. The conductive member 40 is not disposed between the multi-row piezoelectric array element 111, the substrate layer 20, and the acoustic matching layer 30, so that the piezoelectric layer 10, the substrate layer 20, and the acoustic matching layer 30 can 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 array element 111 and the substrate layer 20 and the acoustic matching layer 30 is improved.

[0122] In one embodiment, step S100 includes the following steps:

[0123] S101: Polish the substrate 11 to flatten its surface, which will facilitate the subsequent deposition of the first electrode layer 12. Polishing also controls the thickness of the substrate 11.

[0124] S102: Polish the finished substrate 11. Optionally, polish with 4000-grit alumina.

[0125] 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.

[0126] 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.

[0127] S105: Grind the substrate 11 to remove excess insulating adhesive 112.

[0128] Optionally, the extended support 113 can be cut from the substrate 11, that is, multiple rows of piezoelectric units and the extended support 113 are cut out simultaneously in step S103, and then insulating adhesive 112 is filled between the extended support 113 and the piezoelectric units in step S104 to improve production efficiency. It is understood that in other embodiments, the extended support 113 can also be insulating ceramic, glass or high-resistivity silicon wafer, and is not limited here.

[0129] In one embodiment, step S200 includes the following steps:

[0130] S201: An adhesion-enhancing layer 121, a main conductive layer 122, and an antioxidant layer 123 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.

[0131] S202: Cut the first electrode layer 12 along the row direction X, and fill the cut with insulating adhesive 112. Optionally, the cutting tool, cutting position, cutting parameters and step S103 are the same.

[0132] Furthermore, after step S202, the fabrication method further includes step S203: polarizing the substrate 11 at room temperature under a constant electric field of 10 kV / cm for 30 minutes. The polarized region is the multi-row piezoelectric array 111, and the extended support 113 is not polarized, that is, the extended support 113 does not generate piezoelectric signals and does not actively generate mechanical vibrations.

[0133] In one embodiment, the step of electrically connecting the conductive element 40 to at least one end of the first electrode layer 12 specifically includes:

[0134] S301: Conductive elements 40 are alternately connected to both ends of the first electrode layer 12.

[0135] S302: The end of the conductive element 40 is fixed to the first electrode layer 12 using an insulating adhesive 112.

[0136] S303: Compress the pads of the conductive element 40 to connect the pads of the 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.

[0137] Optionally, after step S303, step S304 is also included: using a multimeter to check for short circuits.

[0138] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A one-dimensional array ultrasonic transducer, characterized in that: The one-dimensional array 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 an extended support member and multiple rows of piezoelectric elements spaced apart along the column direction. Adjacent rows of piezoelectric elements are bonded together with an insulating adhesive. The extended support member is connected to at least one side of the multiple rows of piezoelectric elements in the row direction. The piezoelectric layer also includes multiple first electrode layers spaced apart along the column direction on one side of the substrate, each first electrode layer covering one row of piezoelectric elements. The thickness direction is perpendicular to both the row direction and the column direction. The first electrode layer extends to at least one end of the extended support in the row direction and is electrically connected to a conductive element on the extended support; The material of the extended support is the same as that of the piezoelectric array element, and the extended support is not polarized. The first electrode layer includes an adhesion-enhancing layer, a main conductive layer, and an antioxidant layer sequentially stacked on the substrate along the thickness direction, and the thickness of the first electrode layer is less than or equal to 10 μm; The piezoelectric array element is cut from a brittle single crystal. The center frequency of the one-dimensional array ultrasonic transducer is greater than or equal to 15 MHz; The piezoelectric array element is rectangular, and the side length of the piezoelectric array element in the column direction is 80μm to 110μm.

2. The one-dimensional array ultrasonic transducer according to claim 1, characterized in that: The conductive component includes an insulating plate and metal wires disposed on the insulating plate. The number of metal wires is the same as the number of the first electrode layers and corresponds one-to-one. The insulating plate is connected to the extended support, and the metal wires are electrically connected to the corresponding first electrode layers.

3. The one-dimensional array ultrasonic transducer according to claim 2, characterized in that: The insulating plate is a flexible plate.

4. The one-dimensional array ultrasonic transducer according to claim 1, characterized in that: The conductive element is a conductive line that corresponds one-to-one with the first electrode layer. The first end of the conductive line is electrically connected to the corresponding first electrode layer, and the second end of the conductive line extends away from the substrate. In two adjacent conductive lines, the interval between their second ends is greater than the interval between their first ends.

5. The one-dimensional array ultrasonic transducer according to claim 4, characterized in that: The conductive line includes a first straight segment and a second straight segment. The two ends of the first straight segment are respectively connected to the first electrode layer and the second straight segment. The first straight segment is set at an acute angle to the column direction and extends toward the end of the substrate in the column direction. The second straight segment is parallel to the row direction and the line width of the second straight segment is greater than the line width of the first straight segment.

6. The one-dimensional array ultrasonic transducer according to claim 1, characterized in that: The one-dimensional array ultrasonic transducer further includes an insulating support member located on the outside of the substrate, and the conductive element located on the outside of the substrate is supported by the insulating support member.

7. The one-dimensional array ultrasonic transducer according to claim 1, characterized in that: The first electrode layer is located on the side of the substrate near the acoustic matching layer, and the piezoelectric layer further includes a second electrode layer disposed on the side of the substrate near the substrate layer, the second electrode layer covering multiple rows of the piezoelectric array elements.

8. The one-dimensional array ultrasonic transducer according to claim 1, characterized in that: The extended support is connected to the opposite sides of the multiple rows of piezoelectric array elements in the row direction, and the first electrode layer extends to the extended support at both ends in the row direction and is alternately connected to the conductive elements.

9. The one-dimensional array ultrasonic transducer according to claim 1, 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.

10. The one-dimensional array ultrasonic transducer according to claim 1, 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.

11. The one-dimensional array ultrasonic transducer according to claim 1, characterized in that: The one-dimensional array ultrasonic transducer also includes: The center-to-center distance between adjacent first electrode layers is 10 μm to 100 μm.

12. The one-dimensional array ultrasonic transducer according to any one of claims 1 to 11, 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 7 MRayl and less than 15 MRayl.

13. A method for fabricating a one-dimensional array ultrasonic transducer as described in claim 1, characterized in that, The method includes the following steps: S100: The substrate is cut into multiple rows of piezoelectric array elements along the row direction, insulating adhesive is filled in the gap between two adjacent rows of piezoelectric array elements, and an extension support is connected to the outside of the multiple rows of piezoelectric array elements. S200: A plurality of first electrode layers are deposited on one side of the substrate along the thickness direction, each first electrode layer covering a row of the piezoelectric array elements, and at least one end of the first electrode layer in the row direction extends to the extended support. S300: Electrically connect the conductive element to at least one end of the first electrode layer extending to the extended support; S400: Cover one side of the substrate with a substrate layer and cover the other side of the substrate with an acoustic matching layer; The material of the extended support is the same as that of the piezoelectric array element, and the extended support is not polarized. The first electrode layer includes an adhesion-enhancing layer, a main conductive layer, and an antioxidant layer sequentially stacked on the substrate along the thickness direction, and the thickness of the first electrode layer is less than or equal to 10 μm; The piezoelectric array element is cut from a brittle single crystal. The center frequency of the one-dimensional array ultrasonic transducer is greater than or equal to 15 MHz; The piezoelectric array element is rectangular, and the side length of the piezoelectric array element in the column direction is 80μm to 110μm.

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