Piezoelectric composite co-form matrix and method of making

Abstract

The present application relates to a kind of piezoelectric composite co-forming matrix and its preparation method, belong to piezoelectric material technical field.The purpose of the present application is to solve the problems that piezoelectric composite is difficult to form curve in existing transducer matrix, transducer array is placed in large space, preparation cycle is long.The present application uses 1-3 connected piezoelectric composite as matrix, integrally forms curved transducer matrix, not only can solve the problems such as existing transducer matrix process complex, time-consuming, poor consistency of element, but also can realize the miniaturization and co-forming bending dual functions of matrix, so that transducer matrix can easily meet the needs of a variety of curved surface applications.

Description

TECHNICAL FIELD

[0001] The present application relates to a piezoelectric composite co-forming matrix and a preparation method thereof, and belongs to the technical field of piezoelectric materials. BACKGROUND

[0002] An ultrasonic transducer is a sensor for realizing mutual conversion of electrical and acoustic signals, and can be divided into piezoelectric, electromagnetic, capacitive and other types of devices according to working mechanism. Among these transducer types, piezoelectric transducers are favored by acoustic workers due to their high performance, high stability, easy processing and low cost, and have been widely used in research fields such as nondestructive testing, ocean exploration, medical imaging, etc. A transducer matrix (also known as a transducer array) is formed by arranging a plurality of transducer units according to a certain geometric structure, and is currently assembled in an array by manual positioning. According to practical needs, it can be arranged in a linear array, spherical array, arc array, cylindrical array, etc. to meet the acoustic indicators of transducer matrix such as high-power emission, high focusing accuracy, large beam opening angle, etc. Although the traditional transducer array technology can meet the needs of various application scenarios, the preparation process is complex, time-consuming, the yield is low, the array element consistency is poor, and the volume is large, which are the key points for improvement by relevant researchers. In addition, in the field of underwater acoustic detection, with the popularization and application of UUV, underwater robots and other technologies, it is also an urgent problem to develop a miniaturized transducer matrix that can adapt to various curved shell structures.

[0003] Piezoelectric composites are commonly used sensitive materials for making acoustic transducers, usually adopting a 1-3 connected structure. It is a two-phase transduction material composed of one-dimensional linearly arranged piezoelectric phase and three-dimensionally connected polymer phase, which has outstanding thickness vibration mode, low acoustic impedance, high electromechanical coupling coefficient and other excellent performances, and is widely used in the development of transducer sensitive elements. However, the piezoelectric composites currently used in ultrasonic transducers are mostly made of hard piezoelectric ceramics and rigid epoxy resin, and the whole is an uncontrollable element. In terms of structure, it is mostly designed as a plane, which is difficult to meet the application requirements of complex curved surfaces. SUMMARY

[0004] The purpose of the present application is to solve the problems of the existing transducer matrix, such as the difficulty of piezoelectric composite material to form a curved surface, the large transducer array placement space, and the long preparation period. The present application provides a piezoelectric composite co-forming matrix and a preparation method thereof. The present application uses 1-3 connected piezoelectric composite material as the matrix to integrally form a curved transducer matrix, which not only solves the problems of complex process, long time-consuming, poor element consistency of the existing transducer matrix, but also realizes the miniaturization and co-forming bending of the matrix, making the transducer matrix easily meet the needs of various curved surface applications.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] A co-molded array based on piezoelectric composite material, which comprises piezoelectric composite material elements, a rubber mesh frame, an electrode layer, a flexible circuit board and a backing layer.

[0007] Further, the piezoelectric composite material elements are made of piezoelectric material and rigid polymer. The rigid polymer can make the elements have certain rigidity, so that the elements have high transmitting performance and anti-external pressure capability, and the vibration mode of the composite material can be concentrated in the thickness direction, thereby meeting the large power transmitting condition of the transducer. In another preferred embodiment, the piezoelectric material can be high-performance PZT series piezoelectric ceramic or piezoelectric single crystal. Such piezoelectric material has high electromechanical coupling coefficient and piezoelectric coefficient, so that the prepared transducer has high sensitivity receiving and large power transmitting performance. In another preferred embodiment, the rigid polymer can be E51 or EP2115 type epoxy resin material, which can enhance the stability of the piezoelectric composite material elements.

[0008] Further, the rubber mesh frame is embedded around the piezoelectric composite material elements for forming a co-molded array with curved surface. Since the rubber has high elasticity, the co-molded array can be applied to various curved shell structures. In another preferred embodiment, the rubber mesh frame can be prepared by using 704 or 705 silicone rubber material. The two types of silicone rubber material have good adhesion and elasticity, so that the piezoelectric composite material elements can be firmly fixed, and the whole array can adapt to various curved shell structures.

[0009] Further, the electrode layer comprises a bottom electrode layer and a top electrode layer, which are uniformly covered on the upper and lower surfaces of the co-molded array. The bottom electrode layer is an array electrode, which is attached to the metal electrode of the flexible circuit board. The top electrode layer is connected to the top surface of all piezoelectric composite material elements.

[0010] Further, the flexible circuit board comprises an array metal electrode, a flexible lead and an encapsulation layer. The size of the array metal electrode should be equivalent to that of the array electrode on the lower surface of the co-molded array, so as to ensure that the array electrode of each element is closely attached to the array metal electrode. The flexible lead is used to connect the array metal electrode, so that the elements of the co-molded array can be controlled. The encapsulation layer is made of polyester material as a base material, which can effectively isolate the lead of the encapsulation layer from the outside world, and has good insulation, good bending property and thin thickness.

[0011] Further, the backing layer is made of a material with high acoustic impedance, which is a curved entity in structure and is fixedly connected to the bottom electrode layer, thereby playing a role of supporting the co-molded array and absorbing clutter. The backing layer can be made into various curved structures such as cylindrical surface, arc surface and spherical surface, so that the co-molded array can be bent and attached to form a curved surface.

[0012] The application gives two preparation methods of piezoelectric composite co-forming matrix according to two different application scenarios, which are as follows:

[0013] First, a preparation method of piezoelectric composite co-forming matrix, characterized in that: the prepared co-forming matrix is a piezoelectric composite curved surface co-forming matrix, which is suitable for small ultrasonic transducers; the specific steps are as follows:

[0014] Step one, preparing a co-forming matrix skeleton; fixing the piezoelectric material plate on the sample table of the cutting machine, cutting the material along the specified direction, and reserving a certain thickness of the material base to prepare the co-forming matrix skeleton;

[0015] Step two, preparing a rubber piezoelectric composite material; taking the co-forming matrix skeleton in step one after cleaning and drying, injecting liquid rubber into the gap of the skeleton, vacuumizing and solidifying to obtain a stable rubber mesh frame; each unit of the co-forming matrix is evenly divided and positioned in the grid of each rubber mesh frame to form a rubber piezoelectric composite material.

[0016] Step three, preparing a micro piezoelectric composite unit skeleton; after polishing the upper and lower surfaces of the rubber piezoelectric composite material in step two, fixing it on the sample table of the laser cutting machine, controlling the laser to form a micro piezoelectric composite unit skeleton;

[0017] Step four, preparing a micro piezoelectric composite unit; after washing the micro unit skeleton prepared in step three with acetone and drying, a certain amount of epoxy resin solution is prepared and poured into the sintering gap of the micro unit skeleton, and after standing and solidifying, the residual epoxy resin impurities are removed to obtain a micro piezoelectric composite unit composed of piezoelectric and epoxy;

[0018] Step five, preparing a bottom electrode layer; polishing the piezoelectric material base, lightly pasting the hollow mask according to the size of the micro piezoelectric composite unit, and then being electrified; removing the mask to form an array bottom electrode layer;

[0019] Step six, molding a curved surface co-forming matrix; aligning the flexible circuit board with the array bottom electrode of the co-forming matrix, then sticking them together with conductive adhesive, and drying and solidifying at a high temperature of 150 DEG C; then, placing the bottom electrode layer of the co-forming matrix after the conductive adhesive is solidified downward, and pressing and pasting it on a hard curved surface backing layer to obtain a curved surface co-forming matrix;

[0020] Step seven, preparing a top electrode layer; electrifying the top surface of the curved surface co-forming matrix to form a uniform top electrode layer; taking a flexible circuit board and pasting it on the top electrode layer to prepare a piezoelectric composite curved surface co-forming matrix suitable for small ultrasonic transducers.

[0021] Further, the step of cutting, the width of the cutting seam between adjacent units is slightly larger than the width of the cutting seam inside the piezoelectric composite unit, so that after filling the rubber material, the co-molded array can be molded into a curved array structure.

[0022] Further, the micro-piezoelectric composite unit skeleton in step three can be prepared by laser cutting method, and the width of the laser cutting seam can be controlled at about 10-50 μm.

[0023] Second, a preparation method of a piezoelectric composite co-molded array, characterized in that: the prepared co-molded array is a piezoelectric composite curved co-molded array, which is suitable for large ultrasonic transducer array for underwater acoustic detection; the specific steps are as follows:

[0024] Step one, preparing a piezoelectric ceramic column array; fixing the piezoelectric material on the cutting machine sample table, and cutting the material along the specified direction with the cutting blade to retain a certain thickness of the material base to obtain a piezoelectric ceramic column array;

[0025] Step two, preparing a piezoelectric composite unit skeleton; keeping the piezoelectric ceramic column array in step one in place, modifying the cutting step to uniformly divide each ceramic column again to form a piezoelectric composite unit skeleton;

[0026] Step three, preparing a rigid piezoelectric composite array; taking the piezoelectric composite unit skeleton in step two to clean and dry, then filling with a rigid polymer glue, vacuumizing and solidifying to obtain a rigid piezoelectric composite array sample, each piezoelectric composite unit in the array is composed of piezoelectric material and rigid polymer.

[0027] Step four, preparing a co-molded array skeleton; polishing the upper and lower surfaces of the rigid piezoelectric composite array in step three to make the cutting machine cut part of the epoxy resin along the x and y directions, and the cutting depth is consistent with the setting in step one to obtain a co-molded array skeleton;

[0028] Step five, preparing a co-molded array; filling the liquid rubber material into the gap of the co-molded array skeleton, vacuumizing and solidifying to obtain a rubber mesh framework, which is connected with the piezoelectric composite unit to form a stable structure; clamping the material, polishing the material base of the co-molded array to obtain a co-molded array;

[0029] Step six, preparing a bottom electrode layer; polishing the upper and lower surfaces of the co-molded array to make the piezoelectric composite units exposed outward by attaching a mask plate; uniformly electrifying the exposed piezoelectric composite units to form an array bottom electrode layer; finally, aligning and attaching the metal electrode of the flexible circuit board with the array bottom electrode layer, and then adhering and solidifying with conductive adhesive for 24 hours;

[0030] Step seven, forming a curved co-molded array; the bottom electrode layer of the co-molded array attached with the flexible circuit board is fixed on the curved backing with the bottom electrode layer facing down, to obtain a curved co-molded array;

[0031] Step eight, preparing a top electrode layer; the curved co-molded array of step seven is subjected to electroplating with the top surface facing up, to form a top electrode layer of the co-molded array; the flexible circuit board is aligned and pasted on the top electrode layer, to obtain a large transducer array suitable for underwater acoustic detection;

[0032] Further, the bottom electrode array in step six can be directly brushed or embedded with a customized metal panel, and the bottom electrode array is respectively led out of a lead wire for independent driving control of the element;

[0033] Further, the flexible circuit board used in the above two preparation methods only contains one metal electrode unit, and the size of the electrode should be comparable to the size of the top electrode of the co-molded array;

[0034] Further, in another preferred example, the piezoelectric composite element made into a 1-3 connected structure can effectively ensure the performance consistency and high electromechanical conversion of each element in the co-molded array.

[0035] Advantages

[0036] 1. The piezoelectric composite material integrated forming transducer array of the present application improves the problems of traditional hand-pasted transducer array, such as heavy weight, large volume, complex preparation process, low yield, etc., and greatly improves the preparation efficiency of the transducer array, which can be mass-produced.

[0037] 2. The piezoelectric composite material element is prepared and divided by the cutting-filling-re-cutting-re-filling method, which can make the element have good consistency; compared with the traditional splicing type hard frame, the introduction of the flexible polymer frame can greatly reduce the coupling between the elements to reduce the vibration interference between the elements.

[0038] 3. The present application ingeniously uses the traditional 1-3 type connected structure on the array to realize the co-molded bending characteristics of the composite material; the 1-3 type piezoelectric composite material connected structure is reserved on each element, which not only enriches the application environment of the array, but also guarantees the acoustic performance of the element. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a schematic diagram of the piezoelectric composite material co-molded array structure.

[0040] Figure 2 It is Figure 1 Further, the specific structure schematic diagram is further illustrated.

[0041] Figure 3 It is a schematic diagram of the metal electrode distribution of the flexible circuit board used in the present application.

[0042] Figure 4 Preparation flow chart for small arcuate array suitable for ultrasonic transducer in Example 1.

[0043] Figure 5 Preparation flow chart for large spherical array suitable for underwater acoustic transducer in Example 2.

[0044] Figure 6 Schematic diagram of wide beam directivity of co-forming array in water of the present application.

[0045] In the figure, 1 - piezoelectric composite co-forming array, 2 - curved backing, 3 - rubber mesh frame, 4 - flexible circuit board, 5 - electrode layer, 6 - piezoelectric composite element, 7 - metal electrode. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present application more clear and obvious, the present application is further described in detail below with specific examples and the accompanying drawings.

[0047] Figure 1 A schematic diagram of a piezoelectric composite co-forming array structure is given. The piezoelectric composite co-forming array is made according to the integrated composite process of a plurality of rigid piezoelectric composite elements, and a flexible polymer mesh frame with high elasticity and firmness is adhered around each element. The user can bend the co-forming array to the required shape for use. The present application can also be applied to ship hulls, molds and metals with curved surface structures. Since the co-forming array is connected to a high-elasticity flexible polymer frame, it can be pressed and adhered to the surface of each curved structure, Figure 1 A case of the co-forming array adhering to a curved backing structure is given. It is worth noting that the curved surface can also be a cylindrical or hyperbolic structure. When the ultrasonic transducer is used to form a focused sound field, the curved backing can also be made into a concave structure, and the co-forming array is attached to the inner surface of the concave structure.

[0048] Figure 2 A schematic diagram of the structural details of the co-forming array is given. The upper and lower surfaces of the co-forming array are connected to an electrode layer, and the lower surface is a uniform electrode array. The electrode array can be made by methods such as silver glue brushing-mechanical separation, embedded array electrode plate, mask-covered electrode, etc. according to the size of the transducer; the outer side of the electrode layer is attached to a flexible circuit board for conducting electrical signals, Figure 3A layout structure of a flexible circuit board is provided. The metal electrode of the top flexible circuit board uses a square metal electrode as the contact surface, which is attached to the top electrode of the conformal array. The metal electrode can also be circular or other shapes, and the size of the electrode surface is determined according to the size of the flexible circuit board. The metal electrodes of the bottom flexible circuit board adopt an array structure corresponding to the conformal array (if the array size is 16×16, then the electrode array size is also 16×16). Each metal electrode of the bottom flexible circuit board is connected by a flexible lead (not shown in the figure). One end of the lead is connected to the array metal electrode, and the other end can be connected to an external output port for outputting the elemental signal of the piezoelectric composite material. The lead is wrapped with an insulating and waterproof polyester material. The flexible circuit board and the conformal array can be bonded together using polypropylene (PP) material by compression molding. This type of adhesive has a viscosity as high as 3500 c·P and can be fully cured within 48 hours. During bonding, some metal powder or liquid metal can be added to the polypropylene material to enhance conductivity. Based on the structural features of the present invention, two fabrication schemes are given below for a small arc-shaped array suitable for medical ultrasound and a large spherical array for underwater acoustic detection.

[0049] Example 1: A method for fabricating a conformal arc-shaped array suitable for small ultrasonic transducers

[0050] Ultrasonic imaging within living organisms is typically achieved using handheld ultrasonic transducers. Each ultrasonic transducer contains several interconnected micro-ultrasonic units, typically in the millimeter or micrometer range. These units require high precision and consistency in the market. For curved structures such as convex and concave arrays, conventional splicing processes are quite challenging, making it difficult to guarantee consistency. Figure 4 A flowchart for fabricating small curved conformal arrays suitable for ultrasound is presented. The cutting process can combine mechanical cutting and laser micromachining to fabricate curved structures such as convex and concave arrays. The specific process is as follows:

[0051] Step 1: Prepare the conformal array framework by cutting in one step

[0052] Take a small polarized piezoelectric ceramic plate, fix it on the sample stage of a mechanical scribing machine, set the cutting parameters so that the metal blade cuts along the x and y directions to form a prototype array with a ceramic substrate; clean the skeleton sample with anhydrous ethanol and dry it to obtain a conformal array skeleton with a 1-3 interconnected structure.

[0053] Step 2: Preparation of rubber piezoelectric composite material

[0054] Take the co-type matrix skeleton in step one, uniformly inject liquid rubber into the gap of the skeleton, then place the sample into a vacuum box for constant temperature vacuumizing, until no bubbles are produced on the surface of the sample, then take it out and solidify for 24 h at a constant temperature of 20℃, to form a stable rubber network frame; connect the rubber network frame with the piezoelectric composite element to form a rubber piezoelectric composite material.

[0055] Step three, secondary cutting to prepare 1-3 piezoelectric composite micro-element skeleton

[0056] After the rubber composite material in step two is solidified, remove the rubber impurities on the surface and around the sample and polish the upper and lower surfaces; fix the polished composite material sample on the sample table of the laser cutting machine, align the objective lens one by one with the elements divided in step one; set the cutting parameters and array scale, make the laser repeatedly burn the specified area, and then form several concave grooves on the surface of the element, after the single direction burning is completed, adjust the laser cutting direction to rotate 90°, and finally get a stable 1-3 piezoelectric composite micro-element skeleton.

[0057] Step four, preparation of 1-3 piezoelectric composite micro-element

[0058] Take the acetone liquid to clean the micro-element skeleton prepared in step three, wipe and dry; inject the pre-configured epoxy resin glue solution into the sample, then place it in a vacuum box for vacuumizing, until there are no bubbles on the surface of the sample, then take it out and solidify for 24 h at 20℃ to shape, to prepare a 1-3 piezoelectric composite micro-element.

[0059] Step five, preparation of array bottom electrode layer

[0060] Gently scrape off the epoxy resin impurities on the surface and around the 1-3 piezoelectric composite micro-element in step four with a blade, then place it on the sample table of the mechanical scribing machine for cutting, clean and polish the sample again; gently paste the pre-prepared hollow mask according to the size of the element, then place it in the magnetron sputtering instrument, set the instrument parameters, and deposit the electrode on the 1-3 piezoelectric composite micro-element in step four, then remove the mask plate to form a stable array bottom electrode layer.

[0061] Step six, molding of arc surface co-type matrix

[0062] Brush a little high-viscosity conductive adhesive on the flexible circuit board, then align and paste it with the array electrode in step five, and press it tightly with a weight and solidify for 24 h; after solidification, clean the adhesive impurities on the surface of the sample with anhydrous ethanol, bend the cleaned sample to the arc backing, and bond and solidify it with high-viscosity conductive adhesive for 24 h, so that the co-type matrix sample forms a stable arc surface structure.

[0063] Step seven, preparation of top electrode layer

[0064] Take the arc-shaped co-molded array of step six and polish the top. Apply high-purity conductive silver glue evenly to the top surface of the sample, then place it in a 200°C environment oven for 1 hour to dry. The top electrode is complete. Place the top flexible circuit board tightly on the top electrode, and follow step six to adhere the top electrode and flexible circuit board firmly to make a piezoelectric composite arc-shaped co-molded array.

[0065] Example 2: A large spherical co-molded array preparation method suitable for underwater acoustic detection

[0066] In underwater acoustic applications, underwater acoustic transducer arrays with high receiving and transmitting response and large beam opening angle can capture more acoustic information and improve detection accuracy. The present application can use large blocks of piezoelectric composite materials to integrate the array-element preparation, Figure 5 A large spherical array process flowchart for underwater acoustic detection is given. The size of this type of array can be made very large according to the hull or UUV shell, so the cutting method can use pure mechanical cutting. The specific process is as follows:

[0067] Step 1: Preparation of piezoelectric ceramic column array

[0068] Take a large block of piezoelectric ceramic panel and fix it on the sample table of the dicing machine. Set the cutting parameters so that the blade cuts along the x and y directions to form a piezoelectric ceramic column array with a ceramic base.

[0069] Step 2: Secondary cutting to prepare 1-3 type piezoelectric composite element skeleton

[0070] Keep the sample position in step 1 unchanged, modify the cutting step to evenly divide each ceramic column into a 1-3 type connected structure, then place the sample in an ultrasonic cleaning machine for cleaning, wipe and dry to obtain a 1-3 type piezoelectric composite element skeleton.

[0071] Step 3: Preparation of rigid piezoelectric composite array

[0072] Take the 1-3 type piezoelectric composite element skeleton in step 2, fill the pre-configured epoxy resin solution into the sample's cutting groove, then place it in a vacuum box to extract vacuum until there are no bubbles on the sample surface, then take it out and solidify at 20°C for 24 hours. Repeat the polishing of the surface of the sample to remove excess epoxy resin impurities to obtain a rigid piezoelectric composite array.

[0073] Step 4: Third cutting to prepare a co-molded array skeleton

[0074] Fix the sample in step 3 on the sample table of the dicing machine, set the cutting parameters so that the blade cuts along the x and y directions to remove the epoxy resin around the 1-3 type piezoelectric composite element.

[0075] Step five, preparation of co-molded matrix

[0076] After the co-molded matrix skeleton in step four is washed with anhydrous ethanol and dried, liquid rubber is injected into the co-molded matrix skeleton, and then the sample is placed in a vacuum box for constant-temperature vacuumizing until no bubbles are generated on the surface of the sample, and then the sample is taken out and cured at a constant temperature of 20 DEG C for 24 hours; after the sample is cured, the rubber impurities on the surface and around the sample are removed, and the upper and lower surfaces of the sample are polished; the sample is clamped on the sample table of a scribe machine to cut the ceramic substrate, and a co-molded matrix is obtained.

[0077] Step six, preparation of bottom electrode layer

[0078] Low-temperature conductive silver glue is taken and uniformly brushed on the surface of each 1-3 type piezoelectric composite element to form a uniform electrode array, and strict separation between the elements should be ensured, and then the sample after the electrode brushing is placed in a 200 DEG C environment oven for drying for 1 hour, and the preparation of the bottom electrode is completed. In addition, in this step, a customized metal plate can also be covered on the top surface of each 1-3 type piezoelectric composite element, and the size of the metal plate should be comparable to the size of each element, and when the element size of the underwater acoustic array is very large, the electrode preparation by the time-consuming magnetron sputtering method is not suitable.

[0079] Step seven, molding of spherical co-molded matrix

[0080] A little high-viscosity conductive glue is brushed on the flexible mask plate, which is then aligned and attached to the array electrode in step six, and a heavy object is used to press and solidify for 24 hours; after solidification, the adhesive impurities on the surface of the sample are cleaned with anhydrous ethanol, the cleaned sample is molded and bent to a spherical backing, and conductive glue is used to adhere and solidify for 24 hours, so that the co-molded matrix sample forms a stable spherical structure.

[0081] Step eight, preparation of top electrode layer

[0082] The top of the sample in step seven is polished, high-purity conductive silver glue is uniformly brushed on the top surface of the sample, and then the sample is placed in a 200 DEG C environment oven for drying for 1 hour, and the top electrode is completed; the top flexible circuit board is tightly attached to the top electrode, and the top electrode and the flexible circuit board are firmly adhered according to step six, and a large spherical co-molded matrix suitable for underwater acoustic detection is obtained.

[0083] Figure 6 The figure is a schematic diagram of the wide-beam directivity of the co-molded matrix in water. The position of the hydrophone in water is kept unchanged, the acoustic center of the transducer array is rotated along the axial direction, at this time the open-circuit voltage value received by the hydrophone changes from 0 degrees to 180 degrees in a fan-shaped structure, the acoustic wave coverage range is wide, and the transducer has the characteristics of wide-beam acoustic wave emission.

[0084] The above detailed description of the specific description, the purpose, technical scheme and beneficial effects of the application are further described in detail, it should be understood that the above description is only a specific embodiment of the application, and is not used to limit the protection scope of the application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A method of piezoelectric composite co-forming an array, the method comprising: The prepared co-forming matrix is a piezoelectric composite curved co-forming matrix, and is suitable for small ultrasonic transducers; the preparation method comprises the following steps: ​ Step one, preparing a co-forming matrix skeleton; fixing a piezoelectric material plate on a cutting machine sample table, cutting the material along a specified direction, and reserving a certain thickness of the material base to prepare the co-forming matrix skeleton; Step two, preparing a rubber piezoelectric composite material; taking the co-forming matrix skeleton in step one after cleaning and air drying, injecting liquid rubber into the gap of the skeleton, vacuumizing and solidifying to obtain a stable rubber mesh frame; each unit of the co-forming matrix is evenly divided and positioned in each grid of the rubber mesh frame to form a rubber piezoelectric composite material; Step three, preparing a micro piezoelectric composite material unit skeleton; fixing the upper and lower surfaces of the rubber piezoelectric composite material in step two after polishing to be flat on a sample table of a laser cutting machine, and controlling laser burning to form a micro piezoelectric composite material unit skeleton; Step four, preparing a micro piezoelectric composite material unit; washing the micro unit skeleton prepared in step three with acetone liquid and air drying; configuring a certain mass of epoxy resin glue solution, pouring into the burning gap of the micro unit skeleton, and removing residual epoxy resin impurities after static curing to obtain a micro piezoelectric composite material unit composed of piezoelectric and epoxy; Step five, preparing a bottom electrode layer; polishing a piezoelectric material base, lightly adhering a hollow mask to the micro piezoelectric composite material unit scale after being electrified, and removing the mask to form an array bottom electrode layer; Step six, molding a curved co-forming matrix; aligning a flexible circuit board with the array bottom electrode of the co-forming matrix, and then adhering them together with conductive adhesive, and then baking and curing at a high temperature of 150 DEG C; then, placing the bottom electrode layer of the co-forming matrix after the conductive adhesive is cured downward, and adhering it to a hard curved backing layer by molding to obtain a curved co-forming matrix; Step seven, preparing a top electrode layer; electrifying the top surface of the curved co-forming matrix to form a uniform top electrode layer; adhering a flexible circuit board to the top electrode layer to prepare a piezoelectric composite curved co-forming matrix suitable for small ultrasonic transducers; The piezoelectric composite units and the rubber mesh frame are connected in parallel to form a piezoelectric composite co-forming matrix; the electrode layer comprises a bottom electrode layer and a top electrode layer, which are evenly covered on the upper and lower surfaces of the co-forming matrix, wherein the bottom electrode layer is an array electrode, the array electrode is adhered to the metal electrode of the flexible circuit board, and the top electrode layer connects the top surface of all piezoelectric composite units; the flexible circuit board comprises an array metal electrode, a flexible lead and a packaging layer; the size of the array metal electrode is equivalent to that of the array electrode on the lower surface of the co-forming matrix, so as to ensure that the array electrode of each unit is closely adhered to the array metal electrode; the flexible lead is used to connect the array metal electrode to achieve controllability of the units of the co-forming matrix; the backing layer is made of a hard material with high acoustic impedance, and is a curved entity in structure, which is fixedly connected with the bottom electrode layer and is used for realizing the curved molding of the piezoelectric composite co-forming matrix.

2. The method of claim 1, wherein: In the cutting process, the width of the cutting gap between adjacent units is slightly larger than the width of the cutting gap inside the piezoelectric composite unit. The micro piezoelectric composite element skeleton in the step three can be prepared by a laser cutting method, and the seam width of the laser cutting can be controlled to be 10-50 μm.

3. A method of co-fabricating an array of piezoelectric composites, characterized by: The prepared co-forming matrix is a piezoelectric composite curved surface co-forming matrix, and is suitable for a large transducer matrix for underwater acoustic detection; the preparation method comprises the following steps: Step one, preparing a piezoelectric ceramic column matrix; the piezoelectric material is fixed on a cutting machine sample table, and a cutting blade is used to cut the material along a specified direction, and a certain thickness of the material base is reserved to obtain the piezoelectric ceramic column matrix; Step two, preparing a piezoelectric composite element skeleton; the piezoelectric ceramic column matrix in step one is kept in place, and the cutting step is modified so that each ceramic column is uniformly divided again to form the piezoelectric composite element skeleton; Step three, preparing a rigid piezoelectric composite matrix; the piezoelectric composite element skeleton in step two is cleaned and dried, then a rigid polymer glue solution is filled, vacuumized and solidified to obtain a rigid piezoelectric composite matrix sample, and each piezoelectric composite element in the matrix is composed of a piezoelectric material and a rigid polymer; Step four, preparation of co-molded matrix skeleton; the upper and lower surfaces of the rigid piezoelectric composite matrix of step three are polished flat, a cutting machine is used to cut off part of the epoxy resin along x , y the direction, and the cutting depth is consistent with the setting of step one, to obtain a co-molded matrix skeleton; Step five, preparing a co-forming matrix; a liquid rubber material is filled in the gap of the co-forming matrix skeleton, vacuumized and solidified to obtain a rubber mesh frame, the rubber mesh frame is connected with the piezoelectric composite element to form a stable structure; the material is buckled, the material base of the co-forming matrix is polished to obtain the co-forming matrix; Step six, preparing a bottom electrode layer; the upper and lower surfaces of the co-forming matrix are polished flat, a mask plate is attached to expose the piezoelectric composite elements outward, the exposed piezoelectric composite elements are uniformly electroplated to form an array bottom electrode layer; finally, the metal electrode of a flexible circuit board is aligned and attached to the array bottom electrode layer, and then conductive glue is used for adhesion and solidification for 24 h; Step seven, forming a curved surface co-forming matrix; the bottom electrode layer of the co-forming matrix attached with the flexible circuit board is fixed downward on a curved surface backing to obtain a curved surface co-forming matrix; Step eight, preparing a top electrode layer; the top surface of the curved surface co-forming matrix in step seven is electroplated to form a top electrode layer of the co-forming matrix; the flexible circuit board is aligned and attached to the top electrode layer to obtain a large transducer matrix suitable for underwater acoustic detection; The piezoelectric composite elements and the rubber mesh frame are connected in parallel to form a piezoelectric composite co-forming matrix; the electrode layer comprises a bottom electrode layer and a top electrode layer, which are uniformly covered on the upper and lower surfaces of the co-forming matrix, wherein the bottom electrode layer is an array electrode, the array electrode is attached to the metal electrode of the flexible circuit board, and the top electrode layer connects the top surfaces of all piezoelectric composite elements; the flexible circuit board comprises an array metal electrode, a flexible lead and an encapsulation layer; the size of the array metal electrode is equivalent to that of the array electrode on the lower surface of the co-forming matrix to ensure that the array electrode of each element is closely attached to the array metal electrode; the flexible lead is used to connect the array metal electrode to achieve controllability of the elements of the co-forming matrix; the backing layer is made of a hard material with high acoustic impedance, and is a curved surface entity in structure, which is fixedly connected with the bottom electrode layer and is used for realizing the curved surface formation of the piezoelectric composite co-forming matrix.

4. The method of claim 3, wherein: The step six bottom electrode array is directly painted or custom metal panel inlay.

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