Piezoelectric composite material, electrode extraction structure and transducer

Abstract

The utility model discloses a piezoelectric composite material, comprising a piezoelectric backing material which comprises a piezoelectric material and a pair of backing materials bonded on the upper surface and the lower surface of the piezoelectric material; the piezoelectric backing material is provided with strip columns and through grooves which are formed by cutting from the surface of the backing material at certain intervals in the thickness direction. Placing a pair of cut piezoelectric backing materials in a mutually cross-aligned manner; the joined pair of piezoelectric backing materials forms a piezoelectric composite material including a piezoelectric material, an insulating adhesive material, and a backing material laminated in this order by removing a portion of the backing material. According to the utility model, through the interdigital operation of cross alignment of the piezoelectric material with the conductive backs on the two surfaces, a structure with a specified gap width between the array elements and the sub-array elements can be obtained, and the processing of the ultra-high frequency array type ultrasonic transducer with a smaller array element gap size is realized. The utility model also provides a corresponding electrode leading-out structure and a transducer.

Description

Technical Field

[0001] This utility model relates to piezoelectric composite materials, and more specifically, to a piezoelectric composite material, an electrode lead-out structure, and a transducer. Background Technology

[0002] Medical ultrasound transducers are sensors that convert electrical signals into ultrasonic signals and vice versa, and are widely used in the field of medical ultrasound diagnosis. Among them, ultra-high frequency (≥20MHz) ultrasound, due to its high frequency, short wavelength, and high resolution, can be used in specific applications such as superficial skin, ophthalmology, and small animal ultrasound, and has high clinical and research value. Ultra-high frequency ultrasound transducers can be classified into single-element and multi-element (array) types according to their structure. Single-element transducers have a fixed focus and cannot perform Doppler blood flow imaging, which limits their applications. Therefore, ultra-high frequency array ultrasound transducers are mostly used in clinical and research fields.

[0003] Traditional ultra-high frequency ultrasonic transducers, due to their high frequency, have extremely small transducer structures and array element sizes, placing very high demands on various manufacturing processes. Among these, array element segmentation is the most challenging. Taking a 40MHz array ultrasonic transducer as an example, the wavelength of the emitted sound waves in human tissue is approximately 37.5μm. Typically, the spacing between transducer array elements must be less than or equal to one wavelength, i.e., 37.5μm; otherwise, grating lobes will form due to the array's directivity, affecting the quality of the ultrasound image. Furthermore, the size of the gaps between array transducers, i.e., the slit width w, is typically required to be w ≤ vs / (4*f) to avoid the shear vibration of the material filling the element gaps affecting the thickness vibration of the piezoelectric material, where vs is the transverse wave velocity of the material filling the element gaps, and f is the transducer's design frequency. For example, with a 40MHz transducer and an epoxy-filled gap with a transverse wave velocity of 1200m / s, the slit width must be less than or equal to 7.5μm. The conventional method for cutting transducer array elements is to use semiconductor grooving machine blades, which can currently only achieve a thickness of 10µm, which cannot meet the requirements for the kerf width of ultra-high frequency transducer array elements.

[0004] Currently, there are two main manufacturing processes for commercially available ultra-high frequency array ultrasonic transducers. One uses lasers to reduce the kerf between array elements to less than 10µm; the other uses semiconductor MEMS processing technology to manufacture c-MUT or p-MUT transducers on integrated circuits, bypassing the kerf gap issue. However, both laser processing and semiconductor processing technologies involve high equipment investment, maintenance costs, and product manufacturing expenses, resulting in high transducer prices and hindering large-scale clinical and research adoption.

[0005] In addition, to improve the performance of ultrasonic transducers, a backing material is usually placed between the electrode lead-out plate and the piezoelectric material. Since the signal from the piezoelectric material needs to be conducted to the electrode lead-out plate during transducer fabrication, the backing material needs to be electrically conductive. There are generally two methods to achieve this: 1) using a conductive backing material; 2) creating a conductive channel within an insulating backing material. Typically, conductive materials are metals with relatively high impedance. Creating a conductive channel within an insulating material requires a specialized backing fabrication process. Both methods have varying degrees of impact on transducer performance, with a greater impact at higher transducer frequencies, particularly for high-frequency two-dimensional array transducers. This is because two-dimensional array transducers require the piezoelectric material to be divided in both the width and length directions to form a column array. For high-frequency two-dimensional arrays, the size of a single pillar is extremely small (less than 0.1 mm). If a conductive strip is inserted into the backing material, the product performance will be significantly affected due to the impedance between the conductive strip and the backing material and the fact that the conductive strip occupies a large volume of the entire backing pillar. If a conductive material is used as the backing, the high impedance of the conductive material will also affect the product performance and increase the difficulty of manufacturing piezoelectric materials.

[0006] The difficulty in manufacturing ultra-high frequency array ultrasonic transducers lies not only in the extremely small gap size between array elements, but also in how to bring out the array element electrodes, which is a common problem in the industry. Utility Model Content

[0007] To address the technical problems in the prior art, the purpose of this utility model is to provide a piezoelectric composite material, an electrode lead-out structure, and a transducer. By performing a cross-finger operation on two piezoelectric materials with backing materials on both sides, a structure with a specified gap width between array elements and sub-array elements can be obtained. This structure serves as the piezoelectric composite material structure for the transducer array elements, enabling the processing of ultra-high frequency array ultrasonic transducers with smaller array element gap dimensions. Furthermore, by setting a limiting structure on the backing material, it is ensured that the position of the piezoelectric composite material does not shift when it is pressed onto the circuit board, thus achieving precise lead-out of the transducer array element electrodes.

[0008] Traditional interdigitated composite materials are only used for piezoelectric bulk materials such as piezoelectric ceramics or piezoelectric single crystals. Depending on the element spacing and gap requirements, the process involves grooving, filling, and interdigitating to ultimately create a 2-2 or 1-3 type composite material. In the interdigitating process, the grooving depth needs to be greater than the final composite material thickness. However, to avoid damaging the piezoelectric material during cutting and to minimize deformation due to different boundary conditions during epoxy curing shrinkage, the grooving depth is typically less than one-third of the piezoelectric material's thickness. Like pure piezoelectric materials, the thickness of piezoelectric composites is inversely proportional to the vibration frequency. For example, a 40MHz piezoelectric composite typically requires a thickness of less than 50μm. Therefore, the thickness of piezoelectric materials used in the interdigitating process is generally required to be greater than 150μm. However, the thicker the piezoelectric material, the higher the cost, especially for piezoelectric single crystal materials, and the longer the time required to thin the piezoelectric material. Taking into account cost and processing risks, for high-frequency composite materials such as 40MHz, the thickness of each piezoelectric material used in the interdigital process is usually in the range of 200-300μm.

[0009] One of the objectives of this invention is to provide a piezoelectric composite material, comprising the following steps:

[0010] A piezoelectric composite material includes: a piezoelectric backing material, the piezoelectric backing material including a piezoelectric material, and a pair of backing materials bonded to the upper and lower surfaces of the piezoelectric material;

[0011] The piezoelectric backing material has strips and grooves along the thickness direction formed by cutting at certain intervals from the surface of the backing material.

[0012] A pair of pre-cut piezoelectric backing materials are placed in a cross-aligned manner, with the strips of one piezoelectric backing material placed in the through groove of the other piezoelectric backing material, and the adjacent strips having gaps filled with insulating adhesive material to join the pair of piezoelectric backing materials.

[0013] The bonded pair of piezoelectric backing materials are formed into a piezoelectric composite material by removing a portion of the backing material. The piezoelectric composite material comprises piezoelectric materials, insulating adhesive materials, and backing materials stacked sequentially, wherein the piezoelectric materials are flush in thickness; and the piezoelectric composite material has gaps between adjacent strips perpendicular to the stacking direction, which are joined by the insulating adhesive material.

[0014] In some embodiments, the piezoelectric material and the backing materials have the same length and width dimensions but different thicknesses. The thickness of the piezoelectric material is T1, and the thicknesses of the pair of backing materials are T2 and T3 respectively; the thickness of the insulating adhesive material is T4, and the total thickness of each piezoelectric backing material is T5 = T1 + T2 + T3 + 2*T4. The positive electrode of one piezoelectric material is bonded to the backing material with a thickness of T2, and the negative electrode is bonded to the backing material with a thickness of T3. The bonding thicknesses of the positive and negative electrodes of the other piezoelectric material to the backing material are opposite.

[0015] In some embodiments, the surface of each piezoelectric backing material is grooved at intervals of 2*P1 to a preset depth:

[0016] If T2 < T3, cut from the surface of the backing material with a thickness of T2, and control one of the backing materials to be cut to a preset depth D1 = T1 + 2*T2 + 2*T4, and the cutting depth of the other backing material is not less than D1; if T3 < T2, cut from the surface of the backing material with a thickness of T3, and control one of the backing materials to be cut to a preset depth D2 = T1 + 2*T3 + 2*T4, and the cutting depth of the other backing material is not less than D2; the piezoelectric materials in the pair of joined piezoelectric backing materials are flush in the thickness direction to define the bars with a width of K2 and a spacing of P1 and the grooves with a width of K1 + K2 and a spacing of 2P1, and a gap with a width of K1 is formed between adjacent bars.

[0017] In some embodiments, in a pair of joined piezoelectric backing materials, the bottom of the through groove of one piezoelectric backing material fits closely with the surface of the backing material of the other piezoelectric backing material.

[0018] In some embodiments, the removed part in the joined piezoelectric backing materials includes completely removing the backing material on one side of the piezoelectric material until the first part of the piezoelectric material is exposed, and also includes the second part of partially removing the backing material on the other side of the piezoelectric material; the gaps between the piezoelectric materials and the joined piezoelectric materials form a substantially flat first surface; the gaps between the backing materials and the joined backing materials form a substantially flat second surface.

[0019] In some embodiments, in the piezoelectric composite material:

[0020] The upper and lower surfaces of the piezoelectric material are plated with electrodes;

[0021] Each upper and lower surface of the backing material has a conductive area for conduction;

[0022] Electrodes are provided on the first surface of the piezoelectric material and the second surface of the backing material in the piezoelectric composite material, or electrodes are provided only on the first surface of the piezoelectric material in the piezoelectric composite material.

[0023] In some embodiments, the piezoelectric composite material is modified by cutting away electrodes located in the gaps of the backing material, with the cutting depth controlled to be less than the thickness of the backing material. A work station groove is formed at the center of two adjacent gaps on the second surface of the backing material at a distance P1. The depth of the work station groove is adjusted to achieve a limiting fit with the conductive pads of the circuit board. Specifically, by controlling the groove depth to achieve a limiting fit with the conductive pads of the circuit board, the piezoelectric composite material is relatively fixedly pressed onto the conductive pads on the surface of the circuit board through the work station groove of the backing material.

[0024] Addressing the aforementioned technical problems in the preparation of composite materials using traditional interdigitated processes, this invention proposes a piezoelectric composite material for obtaining 40MHz composites. This allows for the bonding of a backing material (containing epoxy resin) with a thickness significantly greater than that of the piezoelectric material on both sides, achieving a total thickness exceeding 1mm after bonding, thus significantly increasing the overall strength of the material. During the grooving process, the backing material and piezoelectric material on the upper surface can be cut through and into the conductive backing material on the lower surface. This avoids epoxy curing shrinkage deformation caused by incomplete cutting of the piezoelectric material. Therefore, the thickness of the piezoelectric material can be controlled within the final thickness of the piezoelectric composite material plus processing error (e.g., 10µm), without needing to exceed three times the final thickness of the piezoelectric composite material, reducing the time and cost of thinning the piezoelectric material.

[0025] This invention uses a backing material and a piezoelectric material to interlock, and the cutting depth can be determined by algebraic fitting. Then, combined with the height limiting function of the pressing mold, the piezoelectric material layer is aligned in the thickness direction when the two piezoelectric backing materials are interlocked, so that the piezoelectric material emission surface is kept on the same plane. This ensures the consistency of the matching layer thickness on each array element in subsequent processes and improves the performance of the array elements.

[0026] In traditional interdigitated processes, after obtaining the composite material, electrodes are plated onto both the top and bottom surfaces. When the composite material is used in an array transducer, the coating needs to be cut through to form individual array elements with separate signal electrodes. However, this inevitably cuts into the gaps in the composite material. If a blade is used to cut the coating, the width of the kerf will inevitably be larger than the gaps in the composite material, affecting its acoustic performance and almost negating the purpose of the interdigitated process.

[0027] The second objective of this utility model is to provide an electrode lead-out structure for the above-mentioned piezoelectric composite material, the technical solution of which is as follows:

[0028] An electrode lead-out structure of a piezoelectric composite material includes the piezoelectric composite material, wherein in each piezoelectric backing material, conductive areas are attached to the surfaces of the backing materials bonded to both sides of the piezoelectric material.

[0029] A pair of piezoelectric backing materials are cut to form strips and slots. The slots of the piezoelectric backing materials have a conductive layer around the backing materials for communicating with the conductive region. The cut piezoelectric backing materials are aligned with each other by extending the strips into the slots. At least one piezoelectric backing material has a stepped width that narrows from the outside to the inside of the cut surface, so that a stepped-width gap is formed between adjacent strips in the resulting piezoelectric composite material, and the gap on the wider side is formed inside the backing material. A continuous conductive layer is provided on the second surface of the backing material. The electrode lead-out structure of the piezoelectric composite material is obtained by cutting the continuous conductive layer between adjacent strips.

[0030] In some embodiments, the through-slot includes a first slot formed by cutting one of the piezoelectric backing materials. The first slot includes a shallow slot formed on the backing material on one side of the piezoelectric material and a deep slot penetrating the piezoelectric material into the backing material on the other side. The width of the shallow slot is wider than that of the deep slot. A first conductive layer is provided on the surface of the shallow slot. The first conductive layer extends along the side of the backing material to a portion of the side of the piezoelectric material. The first conductive layer is electrically connected to the conductive area of ​​the backing material in which it is located.

[0031] The through groove also includes a second groove cut from another piezoelectric backing material. The second groove is a straight groove. A conductive layer is provided on the surface of the second groove. By removing the conductive layer from the backing material to the side of part of the piezoelectric material on the second groove, the conductive layer at the bottom is retained to form a second conductive layer. The second conductive layer is connected to the conductive area of ​​the backing material in which it is located.

[0032] The gaps between adjacent bars in the formed piezoelectric composite material are made to have stepped widths, with wider gaps on the side closer to the shallow groove and narrower gaps on the side farther from the shallow groove. A conductive layer is provided on the second surface of the piezoelectric composite material on the side closer to the shallow groove. The electrodes of adjacent bars in the piezoelectric composite material are divided by cutting the conductive layer that connects the adjacent bars.

[0033] This invention utilizes a very small gap between the interdigitated bars, typically less than 0.01 mm. During array element segmentation, the electrodes of each element need to be separated. Traditional cutting methods easily damage the conductive channels, breaking the electrode lead-out channels on the backing. Based on the electrode lead-out method of this invention, a conductive layer can be deposited to extend the conductive layer to a certain position on the inner surface of the bars, thereby establishing electrode lead-out channels for each bar during the interdigitation process. This significantly saves product manufacturing time and reduces the difficulty of electrode lead-out for transducers, especially high-frequency two-dimensional array transducers.

[0034] More specifically, this invention primarily employs a "cutting control method" to control the position of the conductive layer plated on the side of the strip and the size of the strip. Ultimately, the gaps between the strips bonded to the piezoelectric material form narrow gaps, while wide gaps are formed between the backing materials far from the piezoelectric material. Thus, when using this invention to fabricate an array transducer, the segmentation of the array element signal poles is almost automatically completed after the composite material is fabricated. Subsequent steps only require cutting the coating of the conductive backing, without affecting the acoustic performance of the composite material. Simultaneously, the conductive layer plating process can be used to extend the conductive layer to a certain position on the inner side of the backing pillar or backing strip (i.e., the backing material portion within the strip), thereby establishing electrode lead-out channels for each backing strip or backing pillar during the interdigitation process. This significantly saves product manufacturing time and reduces the difficulty of electrode lead-out for transducers, especially high-frequency two-dimensional array transducers.

[0035] The fourth objective of this utility model is to provide a transducer comprising the aforementioned piezoelectric composite material and a circuit board. The technical solution adopted is to connect the piezoelectric composite material to the circuit board through the aforementioned electrode lead-out method.

[0036] Compared to using laser cutting to cut the gaps between transducer elements or using semiconductor processing methods to manufacture transducers, the processing cost and difficulty of the ultra-high frequency array ultrasonic transducer manufactured by this invention are significantly reduced. In addition, the processing method of this invention can theoretically reduce the gap between elements to less than 1µm. Laser processing is limited by the aspect ratio of the slot (usually 1:10). To achieve a gap width of 1µm, the depth of the slot is only about 10µm, which cannot even cut through the piezoelectric material itself, and cannot meet the requirements for transducer element segmentation.

[0037] Beneficial effects:

[0038] 1) This utility model uses interdigitated piezoelectric materials with conductive backing on both sides to complete the structure of specified gap width between array elements and between sub-array elements. Under the premise of ensuring the reliability of the processing process and obtaining high-quality piezoelectric composite materials, it can realize the processing of ultra-high frequency array ultrasonic transducers with smaller array element gap size.

[0039] 2) This invention uses a backing material with a limiting structure to ensure that the gaps between the piezoelectric material sub-element elements are aligned with the circuit board pads, and that the gaps between the elements are aligned with the position between two pads on the circuit board. Furthermore, this invention uses a circuit board structure with specially shaped pads to ensure that the piezoelectric composite material does not shift on the circuit board.

[0040] 3) This utility model utilizes the interdigitated method to establish an electrode lead-out structure for a non-conductive backing material, which simplifies the electrode lead-out process, especially the realization of a high-frequency two-dimensional array, and avoids the problem of affecting product performance and increasing manufacturing difficulty caused by directly using conductive backing materials with excessively high impedance.

[0041] 4) This utility model utilizes interdigitated fingers to create a gap with stepped width, and coats the second surface of the backing material in the piezoelectric composite material with a conductive layer. Then, the electrode division of adjacent columns is achieved simply by cutting the conductive layer on one side of the wider gap between adjacent columns, which greatly facilitates the electrode lead-out in the piezoelectric composite material. Attached Figure Description

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] Figure 1 This is a combined schematic diagram of the piezoelectric material of this utility model from a top view and a front view.

[0044] Figure 2 This is a schematic diagram of a combination of a pair of backing materials according to the present invention.

[0045] Figure 3 This is a schematic diagram of a combination of a pair of piezoelectric backing materials according to the present invention.

[0046] Figure 4 This is a schematic diagram of the cutting of the piezoelectric backing material in one embodiment of the present invention.

[0047] Figure 5 This is a schematic diagram of the interdigitated finger state in one embodiment of the present invention.

[0048] Figure 6 This is a schematic diagram of the piezoelectric composite material in one embodiment of the present invention.

[0049] Figure 7-1 and Figure 7-2 These are top and side views of the piezoelectric composite materials of types 1-3 formed in one embodiment of this utility model.

[0050] Figure 8 This is a schematic diagram of the groove cut in the backing material in one embodiment of the present invention.

[0051] Figure 9 This is a top view of the circuit board pads in one embodiment of the present invention.

[0052] Figure 10-1 and Figure 10-2 These are schematic diagrams showing the electrode leads in one embodiment of this utility model.

[0053] Figure 11 This is a schematic diagram of the pressing mold in one embodiment of the present invention.

[0054] Figure 12 This is a schematic diagram of the cutting process for electrode extraction in one embodiment of the present invention.

[0055] Figure 13This is another cutting diagram illustrating the electrode lead-out in one embodiment of the present invention.

[0056] Figure 14 This is a schematic diagram of the surface structure of the backing material forming the 2-2 piezoelectric composite material in one embodiment of the present invention.

[0057] Figure 15 , 16 These are schematic diagrams of two surface structures of the backing material forming the 1-3 piezoelectric composite material in one embodiment of this utility model.

[0058] Figure 17 This utility model corresponds to Figure 14-16 A schematic diagram of the side structure of the resulting backing material.

[0059] Figure 18 This is a simplified diagram of a transducer in one embodiment of the present invention.

[0060] The meanings of the symbols in the diagram are as follows:

[0061] 10-First piezoelectric material, 10′-Second piezoelectric material, 100-Piezoelectric backing material, 101-First pillar, 102-Second pillar, 103-First groove, 104-Second groove; A-Shallow groove, B-Deep groove, C-Conductive material, S1-First conductive layer, S2-Second conductive layer; S′-Conductive layer, S-Conductive pad, J-Ground pad, E-Conductive area;

[0062] 2-Pressure mold, 20-Upper pressure block, 21-Lower pressure block, 22-Support rod, 23-Limit block;

[0063] 3-Circuit board. Detailed Implementation

[0064] The present invention will be further explained in detail below with reference to the accompanying drawings and specific embodiments. However, the following description of the embodiments is only intended to enable those skilled in the art to better understand the principles and essence of the present invention, and does not imply any limitation on the present invention.

[0065] In the description of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. It should be noted that the following embodiments can be freely combined as needed. It should be pointed out that those skilled in the art can make several improvements and modifications without departing from the principles of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.

[0066] This invention provides a piezoelectric composite material that can produce specific required element gaps by adjusting the width of the cutting slits. Furthermore, it enables the element gaps to be less than 1 μm, achieving low-cost and low-difficulty processing of ultra-high frequency array ultrasonic transducers. This invention will be further described in detail in the following exemplary embodiments.

[0067] refer to Figures 1 to 3 The composite material includes a pair of piezoelectric materials, with a pair of backing materials provided for the upper and lower surfaces of each piezoelectric material. The backing materials and the piezoelectric materials are bonded together. Thus, the pair of backing materials, together with a piezoelectric substrate, form a piezoelectric backing material. The two pairs of backing materials and the pair of piezoelectric materials together form a pair of piezoelectric backing materials. The upper and lower surfaces of the piezoelectric materials refer to the upper and lower surfaces along the thickness direction of the piezoelectric material. Depending on the specific application, the piezoelectric material can be piezoelectric ceramic or piezoelectric single crystal, etc. In one embodiment, the backing material and the piezoelectric material are bonded using an insulating adhesive, specifically epoxy resin adhesive. In another embodiment, it is shown... Figure 1 In the diagram, the pair of piezoelectric materials includes a first piezoelectric material 10 and a second piezoelectric material 10′, both with a length of L, a width of W, and a thickness of T1. (The diagram is shown...) Figure 2 The pair of backing materials includes a first backing material 11 with a length of L, a width of W, and a thickness of T2, and a second backing material 12 with a length of L, a width of W, and a thickness of T3, where T2 ≠ T3. The thickness of the insulating adhesive material is T4. The insulating adhesive material can be glue, and the glue layer thickness T4 is controlled to be less than 5 μm. After bonding, the total thickness of each piezoelectric backing material is T5 = T1 + T2 + T3 + 2 * T4. The positive electrode of one piezoelectric material is bonded to the first backing material 11 with a thickness of T2, and the negative electrode is bonded to the second backing material 12 with a thickness of T3. The positive and negative electrodes of the other piezoelectric material have opposite bonding thicknesses to the backing materials: the positive electrode is bonded to the second backing material 12 with a thickness of T3, and the negative electrode is bonded to the first backing material 11 with a thickness of T2, as shown in the diagram. Figure 3 The piezoelectric material in the composite material already has positive and negative electrodes. The positive and negative electrodes of the two piezoelectric materials are bonded together with backing materials of opposite thicknesses. Of course, if the piezoelectric material has not yet been given polarity during the fabrication process of the piezoelectric composite material, the corresponding polarity can be given to the piezoelectric material through polarization after the final piezoelectric composite material is formed.

[0068] refer to Figure 4By cutting the surface of each piezoelectric backing material 100 at certain intervals, grooves are cut to form posts and through grooves extending along the thickness direction. Specifically, by cutting the surface of one piezoelectric backing material 100 and cutting grooves at certain intervals, first posts 101 and first grooves 103 extending along the thickness direction are formed, with adjacent first posts 101 separated by first grooves 103. By cutting the surface of another piezoelectric backing material 100 and cutting grooves at certain intervals, second posts 102 and second grooves 104 extending along the thickness direction are formed, with adjacent second posts 102 separated by second grooves 104. (Reference) Figure 5 A pair of pre-cut piezoelectric backing materials are placed in a cross-aligned manner, with the first post 101 placed in the second groove 103 and the second post 102 placed in the first groove 104. The gaps between adjacent first posts 101 and second posts 102 are joined by an insulating adhesive to bond the pair of piezoelectric backing materials. In one embodiment, the adjacent first posts 101 are joined by filling the gaps with epoxy resin adhesive.

[0069] refer to Figure 6, after the insulating bonding material is cured, a part of the piezoelectric backing material that has been finger-jointed is removed along the thickness direction to form a piezoelectric composite material. The piezoelectric composite material has two surfaces in the thickness direction. Specifically, the backing material on one side of the piezoelectric material is removed until the piezoelectric material is exposed to form a substantially flat first surface, and a part of the backing material on the other side of the piezoelectric material is removed to form a substantially flat second surface, so as to form a piezoelectric composite material; wherein, both the first surface and the second surface are defined by strip columns and gaps joined by the insulating bonding material between adjacent strip columns. Here, "substantially flat" means meeting the technical index requirements for the flatness of the laminated material layers in this technical field. Both the first surface and the second surface are formed by the alternately adjacent first columns 101 and second columns 102 and the gaps joined by the insulating bonding material. The difference is only that the first surface is formed by the surface of the piezoelectric material layer exposed after removing the backing material on one side of the piezoelectric material by means of grinding, etc. with the first columns 101 and second columns 102 joined by the bonding insulating material, and the second surface is formed by the bottom surface of the retained backing material layer after removing a part of the backing material on the other side of the piezoelectric material by means of grinding, etc. with the first columns 101 and second columns 102 joined by the bonding insulating material. In one embodiment, when cutting any piezoelectric backing material, the cutting is performed from the surface of the thinner backing material. After the two piezoelectric backing materials are finger-jointed, the thicknesses of the backing materials on both sides of the piezoelectric material are the same, and are both the thickness of the thicker backing material. In another embodiment, a blade with a thickness of K1 + K2 or other implementation methods in the industry are used to cut a pair of piezoelectric backing materials, and each piezoelectric backing material is cut to a preset depth at a spacing of 2*P1 on the surface; if T2 < T3, cut from the surface of the first backing material 11 with a thickness of T2, and control one of the backing materials to be cut to a preset depth D1 = T1 + 2*T2 + 2*T4, and the cutting depth of the other backing material is greater than or equal to D1; if T3 < T2, cut from the surface of the second piezoelectric backing material 12 with a thickness of T3, and control the other backing material to be cut to a preset depth D2 = T1 + 2*T3 + 2*T4, and the cutting depth of the other backing material is greater than or equal to D2, so that after the pair of piezoelectric backing materials are joined, the first piezoelectric material 10 and the second piezoelectric material 10' are flush in the thickness direction, forming a flush piezoelectric material layer, so as to define the first columns 101 and second columns 102 with a width of K2 and a spacing of P1, and the first groove 103 and second groove 104 with a width of K1 + K2 and a spacing of 2P1, and form a gap with a width of K1 between the adjacent strip columns, that is, the first columns 101 and second columns 102.In yet another embodiment, an insulating bonding material is coated on the surface of the first groove 101 of a cut piezoelectric backing material 100, and then another cut piezoelectric backing material 100 with the same parameters is inserted and appropriate pressure is applied, usually 1 - 6 MPa, so that the bottom of the first groove 102 of one piezoelectric backing material 100 fits closely with the conductive backing surface of the other piezoelectric backing material 100 to define the gap width between the piezoelectric backing materials ≤ K1. Ideally, the gap widths on both sides of the first column 101 are both 0.5*K1. Figure 5 The vertical black solid area is the gap filled with epoxy resin glue, and the horizontal black solid area is the glue layer between the piezoelectric material 10 and the backing materials 11 / 12. Remove the backing material on one side of the piezoelectric material until the piezoelectric material is exposed to form a substantially flat first surface, and remove a part of the backing material on the other side of the piezoelectric material to form a substantially flat second surface. The first surface and the second surface constitute the surfaces of the piezoelectric composite material in the thickness direction. Among them, the first surface and the second surface are both defined by strip columns and gaps joined by an insulating bonding material between adjacent strip columns. In the piezoelectric composite material: Electrodes are provided on both the first surface of the piezoelectric material and the second surface of the backing material in the piezoelectric composite material, or electrodes are provided only on the first surface of the piezoelectric material in the piezoelectric composite material. Specifically, conductive electrodes can be plated through a metal plating process. In a more specific embodiment, after the glue layer is completely cured, grind off the conductive backing layer on one side of the piezoelectric material. After the piezoelectric material is exposed, grind the piezoelectric material to the required final thickness, and grind the conductive backing on the other side of the piezoelectric material to a conductive backing thickness of T2 or T3. When T2 < T3, grind the conductive backing thickness to be less than or equal to T2; when T3 < T2, grind the conductive backing thickness to be less than or equal to T3.

[0070] According to the specification parameter requirements of the ultrasonic transducer, the strip column width and the gap (element gap) of the piezoelectric composite material can be further reduced in the above implementation manner, or after the grooving and interdigital process of the 2 - 2 type piezoelectric composite material, rotate the cutting direction 90° along the horizontal plane, and then perform the grooving and interdigital process to form a 1 - 3 type piezoelectric composite material with a combined conductive backing layer as shown in FIG. 7.

[0071] The piezoelectric material 10 has electrodes plated on its upper and lower surfaces for conducting electricity. These electrodes include, but are not limited to, a nickel layer and a gold layer. The backing material 11 / 12 is made of a conductive material, such as graphite or metal; or it is made of an insulating material, with electrodes plated on its upper and lower surfaces or conductive material added inside the insulating material, making the upper and lower surfaces of the backing material 11 / 12 conductive. Electrodes are plated on both the upper and lower surfaces of the ground piezoelectric material 10 and the backing material 11 / 12 in the piezoelectric composite material, or electrodes are plated only on the surface of the piezoelectric material 10, forming a 2-2 type piezoelectric composite material with a combined conductive backing layer. That is, the piezoelectric composite material of the present invention is an assembly of a conventional piezoelectric composite material with a backing material.

[0072] refer to Figure 8 For the piezoelectric composite material, the backing material can be processed with a limiting structure to ensure that the sub-element gaps K3 of the piezoelectric composite material are aligned with the conductive pads S of the circuit board, and the element gaps K4 are aligned with the positions between the two conductive pads S of the circuit board, so as to achieve spatial avoidance of electronic components. This is further combined with a circuit board structure with pads of a specific shape, for example, referencing... Figure 9 As shown, the conductive pads are typically in the shape of an "I" to ensure that the piezoelectric composite material does not shift in position on the circuit board.

[0073] In one embodiment, an electrode is cut into the surface of the backing material 11 / 12 using a blade of thickness K4, within the gap defined by the bonding of the insulating adhesive material, i.e., the surface of the element gap. The cutting depth is less than the thickness of the backing material 11 / 12. Then, a cutting blade of thickness K3 is used to cut grooves at intervals P1 at the center positions of the two gaps on the surface of the backing material 11 / 12 to form a work station groove. By controlling the cutting depth, the work station groove is positioned to fit with the conductive pads S of the circuit board, thereby allowing the piezoelectric composite material to be relatively fixedly pressed onto the conductive pads S on the surface of the circuit board through the work station groove of the backing material. More specifically, in one embodiment, the cutting depth is controlled to be appropriately less than the height of the conductive pads on the circuit board; the cutting width K3 is greater than the width of the middle area of ​​the "I"-shaped conductive pads S on the circuit board, but less than the width of the areas at both ends of the "I"-shaped conductive pads S.

[0074] refer to Figure 10-1 / 10-2, Using conductive adhesive, press the backing material 11 / 12 of the piezoelectric composite material onto the "I"-shaped conductive pad S on the surface of the circuit board, leading the positive or negative electrode of the piezoelectric composite material to the back-end circuit. The other polarity of the piezoelectric composite material is led to the corresponding grounding area of ​​the circuit board through the electrode layer plated on the first surface of the piezoelectric composite material, using conductive material C such as conductive silver paste, coating, etc., usually the extra grounding pads J on both sides. At this point, the positive and negative electrodes of the transducer array element have been led out to the back-end circuit.

[0075] In one embodiment, the circuit board pads are in an "I" shape, and the backing material surface has corresponding grooves, forming an interlocking structure. This solves the problem of needing to cut the array elements according to the spacing of the circuit board pads in the traditional UHF ultrasonic transducer manufacturing process. The other polarity of the piezoelectric composite material is led to the corresponding grounding area of ​​the circuit board through the plating on the surface of the piezoelectric composite material using conductive materials (conductive silver paste, coating, etc.), usually the two extra grounding pads J on both sides. At this point, both the positive and negative poles of the transducer array elements have been led out to the back-end circuit. Finally, according to the corresponding process, an acoustic matching layer and an acoustic lens layer are added to complete the final UHF ultrasonic transducer product.

[0076] This invention utilizes the interlocking of backing material 11 / 12 and piezoelectric material 10. It is important to note that the two piezoelectric backing materials 100 must be aligned in the thickness direction when interlocking. Misalignment will cause the piezoelectric material emission surfaces to be off-plane, leading to inconsistent matching layer thicknesses on each array element in subsequent processes, affecting element performance. This invention solves the alignment challenge of piezoelectric materials based on an "algebraic fitting method" and a "mold limiting method." The algebraic fitting method calculates the preset depth of the groove based on the thickness of the cut piezoelectric material 10 and backing material 11 / 12. A high-precision grooving device then cuts the groove to the calculated depth. During bonding, the two piezoelectric backing materials 100 with grooves cut using the same parameters are aligned and pressed together, following the method of aligning the strips with the cut seams. Alternatively, it is sufficient if the depth of the through-groove cut in one piezoelectric backing material is equal to the preset depth, while the other groove remains greater than or equal to that preset depth, thus ensuring alignment of the piezoelectric material layers in the thickness direction. The aforementioned "mold limiting method" sets the cutting depth based on the preset depth of the groove calculated by the "algebraic fitting method," and the set cutting depth is greater than or equal to the depth calculated based on the "algebraic fitting method." After cutting, the uncut surfaces of the two piezoelectric backing materials 100 are respectively attached or adsorbed onto the upper and lower pressure blocks of the pressing mold 2. The final pressing position of the material is determined by adjusting the distance between the upper and lower pressure blocks of the pressing mold.

[0077] refer to Figure 11 The pressing mold 2 includes an upper pressing block 20 and a lower pressing block 21, and a support rod 22 for fixing the upper pressing block 20 and the lower pressing block 21. The upper pressing block 20 is slidably disposed on the support rod 21. After obtaining the grooved material, the uncut surfaces of a pair of piezoelectric backing materials 100 for interdigitated fingers are fixed to the upper pressing block 20 and the lower pressing block 21 of the mold by means of adhesive or adsorption. Figure 11In this way, control the depth of the through-grooves in the pair of cut piezoelectric backing materials to be not lower than the aforementioned preset depth. Place a limit block 23 on the lower pressing block, and the height of the limit block 23 is equal to the preset depth; when T2 < T3, the height of the limit block 23 is equal to TI + 2T3 + 2T4; when T2 > T3, the height of the limit block is equal to T1 + 2T2 + 2T4. Fix the uncut surfaces of the two pieces of interdigital materials to the upper pressing block 20 and the lower pressing block 21 of the pressing die 2 respectively by means of pasting or adsorption; press the upper pressing block 20 and the lower pressing block 21 until the distance between the pressing blocks is equal to the height of the limit block 23. Among them, the limit block can be a limit device with a fixed height or a limit device with an adjustable height. Fine-tune the limit height according to the alignment effect of each layer of materials during pressing, and the specific structure can be set conventionally according to needs.

[0078] For the piezoelectric composite material of the present invention, the piezoelectric backing material 100 has bars and through-grooves formed by cutting. The bars of one piezoelectric backing material are inserted into the through-grooves of another piezoelectric backing material 100 for alternate interdigital arrangement, and there are gaps filled with an insulating bonding material between adjacent bars to form a piezoelectric backing material combination. The piezoelectric backing material combination forms a piezoelectric composite material including a piezoelectric material, an insulating bonding material, and a backing material stacked in sequence by removing part of the backing material; among them, there are also gaps defined by bonding with an insulating bonding material between adjacent bars in the piezoelectric composite material. In one embodiment, for how to remove part of the backing material, it can be carried out as follows: the piezoelectric backing material combination after removing the backing material on one side of the piezoelectric material and removing part of the backing material on the other side of the piezoelectric material forms a piezoelectric composite material with a backing material of a combined predetermined thickness and a piezoelectric material of a predetermined thickness. Specifically, Figure 6 in the order from top to bottom, the piezoelectric material, the insulating bonding material, and the backing material are stacked in sequence to form a 2-2 type piezoelectric composite material. Or by removing part of the backing material on both sides of the piezoelectric material, making the thicknesses of the final backing materials on both sides inconsistent, then performing grooving and interdigital arrangement on the thinner backing material and then removing the backing material on one side of the piezoelectric material until the piezoelectric material is exposed, and removing part of the backing material on the other side of the piezoelectric material, a 1-3 type piezoelectric composite material stacked with a piezoelectric material, an insulating bonding material, and a backing material in sequence from top to bottom can be formed. Combining Figure 7-1 、 7-2 As shown, the upper and lower surfaces of the 1-3 type piezoelectric composite material form a grid pattern, which is different from the strip-shaped upper and lower surfaces of the 2-2 type piezoelectric composite material, but the stacked materials in the thickness direction are the same.

[0079] Reference Figure 12-17This is an electrode lead-out structure for a piezoelectric composite material. Based on the aforementioned piezoelectric composite material, in each piezoelectric backing material 100, the surfaces of the first backing material 11 and the second backing material 12, bonded to both sides of the piezoelectric material 10 / 10′, each have a conductive region E. Here, "both sides of the piezoelectric material" refers to the upper and lower surfaces of the piezoelectric material along its thickness direction. Both the first backing material 11 and the second backing material 12 are insulating, non-conductive backing materials. In specific applications, such as... Figure 12-13 As shown, the first backing material 11, the second backing material 12, and the piezoelectric material form two conductive regions E, one as the signal electrode and the other as the ground electrode, which are disconnected from each other. A pair of piezoelectric backing materials 100 are cut to form strips and slots. The slots of the piezoelectric backing materials 100 have a conductive layer around the backing material for communication with the conductive region E. The cut piezoelectric backing materials 100 are aligned by inserting the strips into the slots. At least one piezoelectric backing material 100 has a stepped width that narrows from the outside to the inside of the cut surface, creating a stepped-width gap between adjacent strips in the resulting piezoelectric composite material. The wider gap is formed within the backing material. A continuous conductive layer is provided on the second surface of the backing material. By cutting the continuous conductive layer between adjacent strips, the electrode lead-out structure of the piezoelectric composite material is obtained. This allows for easy cutting and separation of the wider gap to facilitate electrode lead-out.

[0080] In one embodiment, the through-slot includes a first slot 103 formed by cutting one of the piezoelectric backing materials 100. The first slot 103 includes a shallow slot A disposed within a backing material 11 layer on one side of the piezoelectric material and a deep slot B penetrating the piezoelectric material 10 to a backing material 12 on the other side. The width of the shallow slot A is wider than the deep slot B. See also Figure 12 A first conductive layer S1 is deposited on the surface of shallow tank A. The first conductive layer S1 extends along the side of the first backing material 11 to a portion of the side of the piezoelectric material 10. The conductive region E where the first conductive layer S1 is bonded to the backing material is correspondingly conductive. Figure 12 The first conductive layer S1 is actually connected to the conductive region E of the first backing material 11 (shown as...). Figure 12 The upper conductive region E) is in an adhesive state, that is, the electrode bonded to the backing material where the first conductive layer S1 is located is conductive, and is connected to the other electrode (shown as...). Figure 12 The lower conductive region E) is disconnected.

[0081] The through-slot also includes a second slot 104 formed by cutting another piezoelectric backing material 100. The second slot 104 is a straight slot. See [link / reference needed] Figure 13A conductive layer is deposited along the surface of the second groove 104. Then, the coating on the second backing material 12 of the second groove 104 is cut to the side of a portion of the piezoelectric material 10 / 10′, leaving the bottom coating to form the second conductive layer S2. The second conductive layer S2 is connected to the conductive area E to which the backing material containing the second conductive layer S2 is bonded. Figure 13 The second conductive layer S2 is actually bonded to the conductive region E (shown as the lower layer in the diagram) of the second backing material 12, meaning that the electrode bonded to the second conductive layer S2 and the backing material containing the second conductive layer S2 is conductive, while the electrode bonded to the other electrode (shown as...) is conductive. Figure 13 The upper conductive region E) is disconnected.

[0082] The gaps between adjacent bars in the formed piezoelectric composite material are made to have stepped widths, with wider gaps on the side closer to shallow groove A and narrower gaps on the side farther from shallow groove A. A continuous conductive layer S′ is deposited on the second surface of the backing material 11 on the side closer to shallow groove A in the piezoelectric composite material. Then, the electrodes of adjacent bars in the piezoelectric composite material are divided by cutting the continuous conductive layer S′ between adjacent bars.

[0083] In this process, two piezoelectric backing materials 100 coated with a first conductive layer S1 and a second conductive layer S2 are interdigitated. More specifically, a first pillar 101 of one piezoelectric backing material is placed in a second groove 104 of another piezoelectric backing material, and a second pillar 102 of one piezoelectric backing material is placed in a first groove 103 of another piezoelectric backing material. A gap filled with an insulating adhesive material exists between adjacent first pillars 101 and second pillars 102, forming a piezoelectric composite material. After removing the backing material from one side of the piezoelectric material, a portion of the backing material from the other side is removed to a predetermined thickness, for example, a thickness not exceeding the smaller of T2 or T3. This thickness difference can be removed by grinding, forming a substantially flat first surface and a second surface. A conductive layer is then deposited onto the second surface of the backing material in the piezoelectric composite material. Finally, electrodes are separated between adjacent first pillars 101 and second pillars 102 in the piezoelectric composite material.

[0084] Based on the aforementioned electrode lead-out method, the total depth of the grooves, which is also the total depth of shallow groove A and deep groove B, is greater than the thickness of the backing material but less than the sum of the thicknesses of the backing material and the piezoelectric material 10, as described in the aforementioned embodiment. The total depth of the grooves is the same as described in the aforementioned reference. Figure 6Embodiment of the cutting method, for example, cutting each surface of the piezoelectric backing material to a preset depth at a uniform pitch; if T2 < T3, cutting from the surface of the first backing material 11 with a thickness of T2, controlling the cutting depth to reach the preset depth D1 = T1 + 2*T2 + 2*T4, then the cutting depth of the second backing material 12 ≥ D1; if T3 < T2, cutting from the surface of the second piezoelectric backing material 12 with a thickness of T3, controlling the cutting depth to reach the preset depth D2 = T1 + 2*T3 + 2*T4, then the cutting depth of the first backing material ≥ D2, so that after the pair of piezoelectric backing materials are joined, the piezoelectric materials therein are flush in the thickness direction to define the first column 101 and the second column 102 with a constant pitch, and a gap with a stepped width that is wide from the cutting surface and narrow inward is formed between the adjacent first column 101 and the second column 102. Thus, by the "cutting control method", the position of the conductive layer plated on the side of the strip column and the size of the strip column are controlled. Finally, in the piezoelectric composite material, a narrow gap is formed between the strip column gaps bonded to the piezoelectric material through the insulating bonding material, and a wide gap is formed between the backing materials far from the piezoelectric material.

[0085] In a more specific embodiment, a piezoelectric backing material 100 is used. The piezoelectric backing material 100 includes a piezoelectric material 10, and the first backing material 11 and the second backing material 12 on the upper and lower surfaces of the piezoelectric material 10: the first backing material 11 and the second backing material 12 are bonded to the piezoelectric material 10 through an insulating bonding material; wherein, the surfaces of the first backing material 11 and the second backing material 12 close to the piezoelectric material both have a conductive region E; along one piezoelectric backing material 100, such as Figure 12 shown, first cut a shallow groove A inward from the surface of the thinner first backing material 11: then plate a first conductive layer S1 on the surface of the shallow groove A (including the top surface of the backing material), and the first conductive layer S1 extends along the side surface of the first backing material 11 to a part of the side surface of the piezoelectric material 10, and the first conductive layer is electrically connected to the conductive region E; then cut a deep groove B, and the width of the deep groove B is smaller than the width of the shallow groove A cutting into the piezoelectric material 10; the shallow groove A is wider than the deep groove B, and the total depth of the cut groove, that is, the total depth of the shallow groove A and the deep groove B constituting the first groove 103, is a preset depth, and this depth is greater than the thickness of the backing material therein but less than the sum of the thicknesses of the pair of backing materials and the piezoelectric material 10; along another piezoelectric backing material 100, such as Figure 13As shown, the thinner first backing material 11 is cut inward from its surface to a final depth (greater than or equal to the preset depth of the first groove 103), and then a conductive layer is plated. Then, the plating on the backing material 12 of the second groove 104 is cut to a portion of the side of the piezoelectric material 10, leaving the bottom plating to form a second conductive layer S2. The second conductive layer is connected to the conductive region E. The two piezoelectric backing materials 100 are interlocked in a crisscross manner. The backing material on one side of the piezoelectric backing material 100 is completely removed until the piezoelectric material 10 is exposed, forming a basically flat first surface. Part of the thickness of the first backing material on the other side of the piezoelectric material is removed to form a basically flat second surface. The first surface is formed by alternating adjacent piezoelectric materials and narrow gaps filled by insulating adhesive material, and the second surface is formed by backing material and wide gaps filled by insulating adhesive material between adjacent backing materials.

[0086] By forming a piezoelectric composite material with a stepped-width slit structure, electrode segmentation can be easily performed at wider slits. After intercalation of the piezoelectric backing materials, the backing material on both sides of the piezoelectric material has the same thickness. To produce a type 2-2 piezoelectric composite material, the backing material on one side of the piezoelectric material (e.g., bonded to the positive electrode) is ground away, and the backing material on the other side (e.g., bonded to the negative electrode) is ground to the predetermined thickness. If further processing to produce a type 1-3 piezoelectric composite material is required, the backing material on both sides of the piezoelectric material is thinned to expose the grooves filled with insulating adhesive material. The backing material on both sides of the piezoelectric material is ground to two different thicknesses, and then the thinner side of the backing material is cut for intercalation, forming a type 1-3 piezoelectric composite material. For example, forming... Figure 14-16 The 2-2 or 1-3 type piezoelectric composite material is shown. A conductive layer S′ is plated onto the second surface of the backing material of the piezoelectric composite material with a wider gap near the shallow groove. Then, the alternating adjacent first pillars 101 and second pillars 102 in the piezoelectric composite material are divided into electrodes, and the circuit board lead-out electrodes are bonded to the electrodes divided in the piezoelectric composite material. This achieves the electrode lead-out function simply and with high quality.

[0087] In addition, this utility model also provides a transducer, see [link to related document]. Figure 18 The circuit board 3 is connected to the piezoelectric composite material and the electrode lead-out structure of the piezoelectric composite material.

[0088] The above description, based on the preferred embodiments of this utility model, provides inspiration. Those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification but must be determined according to the claims.

Claims

1. A piezoelectric composite material, characterized by, The application relates to a piezoelectric composite material and a manufacturing method thereof. The piezoelectric backing material comprises a piezoelectric material and a pair of backing materials bonded to the upper and lower surfaces of the piezoelectric material; The piezoelectric backing material has a strip column and a through groove in the thickness direction formed by cutting the backing material surface at a certain interval; A pair of cut piezoelectric backing materials are placed in a cross alignment mode, wherein the strip column of one piezoelectric backing material is placed in the through groove of the other piezoelectric backing material, and the gap between adjacent strip columns is filled with insulating adhesive material to bond the pair of piezoelectric backing materials; The bonded pair of piezoelectric backing materials forms a piezoelectric composite material by removing part of the backing material, and the piezoelectric composite material comprises the piezoelectric material, the insulating adhesive material and the backing material which are sequentially stacked, wherein the piezoelectric material is flush in the thickness direction; and the piezoelectric composite material has a gap between adjacent strip columns in the direction perpendicular to the stacking direction which is bonded by the insulating adhesive material.

2. The piezoelectric composite of claim 1, wherein, The piezoelectric material and the backing material have the same length and width and different thicknesses, the thickness of the piezoelectric material is T1, the thicknesses of the pair of backing materials are T2 and T3 respectively, the thickness of the insulating adhesive material is T4, the total thickness of each piezoelectric backing material is T5=T1+T2+T3+2*T4, and the positive electrode bonding thickness of one piezoelectric material is the T2-thickness backing material, the negative electrode bonding thickness is the T3-thickness backing material, and the positive and negative electrode bonding thicknesses of the other piezoelectric material are opposite to those of the backing material.

3. The piezoelectric composite of claim 2, wherein, The surface of each piezoelectric backing material is cut at an interval of 2*P1 to a preset depth: If T2 4. The piezoelectric composite of claim 3, wherein: The piezoelectric material in the bonded pair of piezoelectric backing materials is flush in the thickness direction to define the strip column with the width of K2 and the interval of P1, the cut groove with the width of K1+K2 and the interval of 2*P1, and the gap with the width of K1 between adjacent strip columns.

5. The piezoelectric composite of claim 3 or 4, wherein, In the bonded pair of piezoelectric backing materials, the bottom of the through groove of one piezoelectric backing material is closely attached to the surface of the backing material of the other piezoelectric backing material.

6. The piezoelectric composite of claim 5, wherein, The removed part of the bonded piezoelectric backing material comprises a first part in which the backing material on one side of the piezoelectric material is completely removed to expose the piezoelectric material, and a second part in which the backing material on the other side of the piezoelectric material is partially removed; the piezoelectric material and the bonded gap between the piezoelectric materials form a substantially flat first surface; and the backing material and the bonded gap between the backing materials form a substantially flat second surface. In the piezoelectric composite material: The upper and lower surfaces of the piezoelectric material are provided with electrodes; The upper and lower surfaces of each backing material have conductive areas for conduction; The first surface of the piezoelectric material and the second surface of the backing material in the piezoelectric composite are both provided with electrodes, or only the first surface of the piezoelectric material in the piezoelectric composite is provided with electrodes.

7. The piezoelectric composite of claim 6, wherein, The piezoelectric composite is formed by cutting the electrodes at the gaps of the backing material, and the cutting depth is controlled to be less than the thickness of the backing material; and a work groove is formed at the center of each of two adjacent gaps on the second surface of the backing material with a spacing P1, and the work groove is adjusted in depth to be limitedly matched with the conductive pads of the circuit board.

8. An electrode lead-out structure of a piezoelectric composite, comprising the piezoelectric composite according to any one of claims 1-7, characterized in that: In each piezoelectric backing material, the surfaces of the backing material bonded to both sides of the piezoelectric material are both provided with conductive areas; For a pair of piezoelectric backing materials cut to form a column and a through slot, the through slot of the pair of piezoelectric backing materials is provided with a conductive layer around the backing material for corresponding conduction with the conductive areas; the pair of piezoelectric backing materials cut to form the column and the through slot are cross-aligned with the column extending into the through slot, and at least one of the through slots of the piezoelectric backing materials has a stepped width that narrows from the outside to the inside of the cutting surface, so that a gap with a stepped width is formed between adjacent columns in the piezoelectric composite, and the wider side of the gap is formed in the backing material; a continuous conductive layer is provided on the second surface of the backing material, and the electrode lead-out structure of the piezoelectric composite is obtained by cutting the continuous conductive layer between adjacent columns.

9. The electrode lead-through structure according to claim 8, characterized in that: The through slot includes a first slot formed by cutting one of the piezoelectric backing materials, the first slot includes a shallow slot provided on the backing material on one side of the piezoelectric material and a deep slot penetrating through the piezoelectric material to the other side of the backing material, and the width of the shallow slot is wider than that of the deep slot; the surface of the shallow slot is provided with a first conductive layer, the first conductive layer extends along the side surface of the backing material to part of the side surface of the piezoelectric material, and the first conductive layer is in corresponding conduction with the conductive area of the backing material where the first conductive layer is located; The through slot also includes a second slot formed by cutting the other piezoelectric backing material, the second slot is a straight slot, and the surface of the second slot is provided with a conductive layer; by removing the conductive layer on the backing material to part of the side surface of the piezoelectric material on the second slot, a second conductive layer is formed by retaining the conductive layer at the bottom, and the second conductive layer is in corresponding conduction with the conductive area of the backing material where the second conductive layer is located; The gap between adjacent columns in the piezoelectric composite presents a gap with a stepped width, which is wider on the side close to the shallow slot and narrower on the side away from the shallow slot; the second surface of the piezoelectric composite on the side close to the shallow slot is provided with a continuous conductive layer, and the electrode lead-out structure of the piezoelectric composite is obtained by cutting the continuous conductive layer between adjacent columns.

10. A transducer comprising the piezoelectric composite of any one of claims 1-7, the electrode lead-through structure of claim 8 or 9, characterized in that The piezoelectric composite is connected to the circuit board in conduction through the electrode lead-out structure.

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