Flexible ultrasound patch and method of making the same

Abstract

The present application relates to a flexible ultrasonic patch and a preparation method thereof. The flexible ultrasonic patch comprises: a flexible substrate layer; a interdigital electrode layer arranged on one side of the flexible substrate layer; a piezoelectric layer arranged on the side of the interdigital electrode layer away from the flexible substrate layer; and a mesh electrode layer arranged on the side of the piezoelectric layer away from the interdigital electrode layer. In the flexible ultrasonic patch, the flexible substrate layer is used, the interdigital electrode layer is arranged on one side of the flexible substrate layer, the piezoelectric layer is arranged on the interdigital electrode layer, and the mesh electrode layer is arranged on the piezoelectric layer. The acoustic array element spacing is less than one wavelength, the plane wave compound imaging is realized by using the array lower interdigital electrode row circuit addressing design, and the flexible ultrasonic patch has stable acoustic performance.

Description

Technical Field

[0001] This invention relates to the field of ultrasound technology, and in particular to flexible ultrasonic patches and their preparation methods. Background Technology

[0002] Ultrasound equipment continuously monitors human physiological indicators and data non-invasively. Non-invasive ultrasound imaging provides doctors with a powerful diagnostic method for assessing the function of tissues and organs, representing a key trend in precision medicine and digital healthcare. Traditional piezoelectric transducers utilize the longitudinal vibration model of the piezoelectric layer to achieve sound-to-electric field conversion, which dictates the rigid probe design of polymorphic sandwich structures. Three-dimensional complex surfaces are difficult to effectively detect to transmit pathological information such as biological skull and patella; therefore, a flexible sensor suitable for undeveloped complex surfaces is desired. Existing wearable devices can record and analyze human secretions, blood flow detection, radial artery blood flow rate, etc. However, achieving dynamic imaging detection of internal organs remains a major challenge for wearable devices. Flexible ultrasound equipment holds promise for achieving continuous imaging of internal organs and tissues under synchronous deformation conditions. Existing wearable ultrasound devices rely on mechanical devices to install large ultrasound probes at designated locations on the body; the large size and inflexibility of these locations hinder patient movement and experience.

[0003] Flexible ultrasonic patches need to effectively conform to the curved surfaces of the human body and achieve stable acoustic function under the synchronous deformation of human skin tension. The development challenges of flexible ultrasonic patches lie in the following aspects: First, flexible ultrasonic patches must possess excellent mechanical properties such as tensile strength and high flexibility to adapt to complex surface deformations; second, their structure must meet the requirements of small size and light weight for wearability; third, flexible ultrasonic patches need to have stable acoustic function, which means that the array element design must have micron-scale element center-to-center spacing and meet the required aspect ratio; finally, flexible ultrasonic patches must have a simple and synchronously deformable flexible circuit design, which can achieve stable electrical performance under severe deformation and control the phased array activation mode to achieve multi-modal ultrasonic electronic scanning. Conventional flexible ultrasonic patches have poor acoustic performance stability, making it difficult to meet practical requirements. Summary of the Invention

[0004] Based on this, this application provides a flexible ultrasonic patch with stable acoustic performance and a method for preparing the same.

[0005] A flexible ultrasonic patch, comprising:

[0006] Flexible substrate layer;

[0007] An interdigitated electrode layer is disposed on one side of the flexible substrate layer;

[0008] A piezoelectric layer is disposed on the side of the interdigitated electrode layer opposite to the flexible substrate layer;

[0009] A mesh electrode layer is disposed on the side of the piezoelectric layer opposite to the interdigitated electrode layer.

[0010] In the aforementioned flexible ultrasonic patch, a flexible substrate layer is used, with an interdigitated electrode layer on one side, a piezoelectric layer on the interdigitated electrode layer, and a mesh electrode layer on the piezoelectric layer. Acoustically, the element spacing can be less than one wavelength. Plane wave composite imaging is achieved by using the addressing design of the interdigitated electrode row circuit in the lower layer of the array, so that the flexible ultrasonic patch has stable acoustic performance.

[0011] In one embodiment, the interdigitated electrode layer includes N interdigitated leads with opposite first and second ends, and 2N circuit pins. The N interdigitated leads are arranged side by side and spaced apart. The first ends of each interdigitated lead are connected to form a first connection point, and the second ends of each interdigitated lead are connected to form a second connection point. The N circuit pins are arranged side by side and spaced apart and connected to the first connection point, and the remaining N electrode pins are arranged side by side and connected to the second connection point.

[0012] In one embodiment, the piezoelectric layer covers N insertion guide lines, and the piezoelectric layer includes a plurality of piezoelectric blocks arranged in an N-row and N-column interval matrix, with each row of piezoelectric blocks corresponding to one insertion guide line and connected to the corresponding insertion guide line.

[0013] In one embodiment, each row of piezoelectric blocks is electrically connected to the mesh electrode layer so that each row of piezoelectric blocks shares the mesh electrode layer.

[0014] In one embodiment, the length and width of the piezoelectric layer are both 20mm to 25mm; the thickness of the piezoelectric layer is 290μm to 300μm; the length and width of each piezoelectric block are both 0.5mm; the spacing between four adjacent piezoelectric blocks constitutes an array element spacing, and the length and width of the array element spacing are both 0.25mm to 0.3mm.

[0015] In one embodiment, the flexible ultrasonic patch further includes a first conductive layer disposed between the piezoelectric layer and the N insertion guide wires;

[0016] And / or, the flexible ultrasonic patch further includes a second conductive layer disposed between the piezoelectric layer and the mesh electrode layer.

[0017] In one embodiment, the N insertion guide lines are parallel to each other, and adjacent insertion guide lines are spaced apart.

[0018] Furthermore, the interval between two adjacent insertion guides is 0.25mm to 0.3mm, the length of each insertion guide is 6.5mm to 6.7mm, and the width of each insertion guide is 0.5mm.

[0019] In one embodiment, the flexible substrate layer is a polyimide film, the interdigitated electrode layer is made of copper, and the mesh electrode layer is made of copper.

[0020] And / or, the thickness of the flexible substrate layer is 55μm to 60μm, the thickness of the interdigitated electrode layer is 15μm to 25μm, and the thickness of the mesh electrode layer is 10μm to 15μm.

[0021] A method for preparing a flexible ultrasonic patch includes the following steps:

[0022] An interdigitated electrode layer is disposed on one side of the flexible substrate layer;

[0023] A piezoelectric layer is disposed on the side of the interdigitated electrode layer opposite to the flexible substrate layer;

[0024] A mesh electrode layer is provided on the side of the piezoelectric layer opposite to the interdigitated electrode layer.

[0025] In one embodiment, the step of forming an interdigitated electrode layer on one side of the flexible substrate layer includes:

[0026] A first electrode material layer is attached to the flexible substrate layer;

[0027] The interdigitated electrode layer is formed by micromachining on the first electrode material layer using a laser direct etching process.

[0028] In one embodiment, the step of forming the interdigitated electrode layer by micromachining on the first electrode material layer using laser direct etching includes: micromachining the first electrode material layer using a laser direct etching system to form N interdigitated leads with opposite first and second ends, and 2N circuit pins. The N interdigitated leads are arranged side by side and spaced apart. The first ends of each interdigitated lead are connected to form a first connection point, and the second ends of each interdigitated lead are connected to form a second connection point. The N circuit pins are arranged side by side and spaced apart and connected to the first connection point, and the remaining N electrode pins are arranged side by side and connected to the second connection point, thus obtaining the interdigitated electrode layer.

[0029] In one embodiment, the step of forming a piezoelectric layer on the side of the interdigitated electrode layer opposite to the flexible substrate layer includes:

[0030] A piezoelectric material plate is attached to a base film, and a dicing machine micro-engraving system is used to process the piezoelectric material plate to form multiple piezoelectric blocks;

[0031] Each piezoelectric block is bonded to the side of the interdigitated electrode layer away from the flexible substrate layer using a conductive material, and the piezoelectric blocks are arranged in an N-row and N-column interval matrix, with each row of piezoelectric blocks corresponding to and covering one interdigitated electrode line and connected to the corresponding interdigitated electrode line to form the piezoelectric layer.

[0032] In one embodiment, the step of forming a mesh electrode layer on the side of the piezoelectric layer opposite to the interdigitated electrode layer includes:

[0033] The mesh electrode layer is formed by micro-machining on the second electrode material layer using a laser direct etching process;

[0034] The mesh electrode layer is bonded to the side of the piezoelectric layer away from the interdigitated electrode layer using a conductive material, so that each row of piezoelectric blocks shares the mesh electrode layer. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the laminated flexible substrate layer and the first electrode material layer after bonding in a flexible ultrasonic patch.

[0036] Figure 2 To be Figure 1 The diagram shows the structure after the first electrode material layer is processed into the finger electrode layer;

[0037] Figure 3 In order to be in Figure 2 The diagram shows the structure after a piezoelectric layer is placed on the interdigitated electrode layer.

[0038] Figure 4 for Figure 3 Schematic diagram of the structure behind the medium-voltage electrical layer;

[0039] Figure 5 This is a schematic diagram of the structure of a flexible ultrasonic patch;

[0040] Figure 6 for Figure 5 The diagram shows the structure of the flexible ultrasonic patch viewed from below.

[0041] Figure 7 for Figure 5 A schematic diagram of the flexible ultrasonic patch from a side view angle is shown.

[0042] Figure 8 for Figure 5 The exploded view of the flexible ultrasonic patch shown is shown below.

[0043] Figure 9 for Figure 5 The structural dimensions of the flexible ultrasonic patch are shown in the diagram.

[0044] Figure 10 A schematic diagram of row electrode addressing excitation for a flexible ultrasonic patch;

[0045] Figure 11 This is a schematic diagram of the overall excitation of a flexible ultrasonic patch.

[0046] Figure label:

[0047] 100 - Flexible substrate layer;

[0048] 200 - Intercalation electrode layer; 200' - First electrode material layer; 210 - Intercalation wire; 220 - Circuit pin; 211 - First connection point; 213 - Second connection point;

[0049] 300 - Piezoelectric layer; 310 - Piezoelectric block;

[0050] 400 - Mesh electrode layer; 500 - First conductive layer; 600 - Second conductive layer. Detailed Implementation

[0051] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples and accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0052] like Figure 6 and Figure 7 As shown, one embodiment of this study provides a flexible ultrasonic patch with stable acoustic performance; the flexible ultrasonic patch includes: a flexible substrate layer 100; an interdigitated electrode layer 200 disposed on one side of the flexible substrate layer 100; a piezoelectric layer 300 disposed on the side of the interdigitated electrode layer 200 opposite to the flexible substrate layer 100; and a mesh electrode layer 400 disposed on the side of the piezoelectric layer 300 opposite to the interdigitated electrode layer 200.

[0053] In the aforementioned flexible ultrasonic patch, a flexible substrate layer 100 is used, on one side of which an interdigitated electrode layer 200 is disposed, and a piezoelectric layer 300 is disposed on the interdigitated electrode layer 200. Furthermore, a mesh electrode layer 400 is disposed on the piezoelectric layer 300. Acoustically, the element spacing can be less than one wavelength. Plane wave composite imaging is achieved by utilizing the addressing design of the interdigitated electrode row circuit in the lower layer of the array, thus enabling the flexible ultrasonic patch to have stable acoustic performance.

[0054] like Figure 1As shown, the thickness of the flexible substrate layer 100 is 55 μm to 60 μm. In a specific example, the thickness of the flexible substrate layer 100 is 60 μm. The flexible substrate layer 100 is a polyimide film. It should be noted that the flexible substrate layer 100 is not limited to the above-mentioned film layer, and can also be other flexible materials, such as an elastic hydrogel film.

[0055] like Figure 2 As shown, in some embodiments, the interdigitated electrode layer 200 includes N interdigitated leads 210 having opposite first and second ends, and 2N circuit pins 220. The N interdigitated leads 210 are arranged side by side and spaced apart. The first ends of each interdigitated lead 210 are connected to form a first connection 211, and the second ends of each interdigitated lead 210 are connected to form a second connection 213. The N circuit pins 220 are arranged side by side and spaced apart and connected to the first connection 211, and the remaining N electrode pins are arranged side by side and connected to the second connection 213.

[0056] In the illustrated example, there are eight insertion guide wires 210; there are eight circuit pins 220, of which four circuit pins 220 are arranged side by side and spaced apart and connected to the first connection point 211, and the remaining four electrode pins are arranged side by side and connected to the second connection point 213.

[0057] The interdigitated electrode layer 200 is made of copper. It should be noted that the material of the interdigitated electrode layer 200 is not limited to copper; it can also be other electrode materials, such as conductive materials like silver or gold.

[0058] The N insertion guide lines 210 are parallel to each other, and adjacent insertion guide lines 210 are spaced apart. The spacing between adjacent insertion guide lines 210 is 0.3mm. The length of each insertion guide line 210 is 6.7mm. The width of each insertion guide line 210 is 0.5mm.

[0059] In some embodiments, the piezoelectric layer 300 covers N insertion guide lines 210. The piezoelectric layer 300 includes a plurality of piezoelectric blocks 310 arranged in an N-row and N-column spaced matrix. Each row of piezoelectric blocks 310 covers one insertion guide line 210 and is connected to the corresponding insertion guide line 210.

[0060] The piezoelectric layer 300 has a length and width of 20 mm and a thickness of 290 μm. Each piezoelectric block 310 has a length and width of 0.5 mm. The spacing between four adjacent piezoelectric blocks 310 forms an array element spacing 320; the array element spacing 320 has a length and width of 0.3 mm.

[0061] In some embodiments, the flexible ultrasonic patch further includes a first conductive layer 500 disposed between the piezoelectric layer 300 and the N insertion guide wires 210. The first conductive layer 500 is a conductive silver paste layer. The thickness of the first conductive layer 500 is 10 μm to 15 μm.

[0062] In some embodiments, the thickness of the mesh electrode layer 400 is 10 μm to 15 μm. In one specific example, the mesh electrode layer 400 is a mesh copper film layer. The thickness of the mesh electrode layer 400 is 10 μm.

[0063] In some embodiments, each row of piezoelectric blocks 310 is electrically connected to the mesh electrode layer 400, so that each row of piezoelectric blocks 310 shares the mesh electrode layer 400. Further, the flexible ultrasonic patch also includes a second conductive layer 600, which is disposed between the piezoelectric layer 300 and the mesh electrode layer 400. The second conductive layer 600 is a conductive silver paste layer. The thickness of the second conductive layer 600 is 10 μm to 15 μm.

[0064] like Figure 10 and Figure 11 As shown, the working principle of the above-mentioned flexible ultrasonic patch is as follows:

[0065] Each row of piezoelectric array elements' ground lines are connected to a copper film lead of an interdigitated electrode. Each interdigitated electrode is connected to an external pin. All array element signal lines share the same upper electrode on the same mesh copper film.

[0066] By activating a lower electrode of an interdigitated electrode and an upper electrode of a mesh copper film, all piezoelectric elements corresponding to the interdigitated electrodes in that row can be activated to work.

[0067] Exciting all the interdigitated electrodes and the electrodes on the mesh copper film will excite all the piezoelectric elements to make them work.

[0068] The aforementioned flexible ultrasound patch can achieve a dense flexible ultrasound phased array at the sub-millimeter scale. This flexible ultrasound patch can meet the curvature changes of the skin surface such as the human chest cavity, and meets the requirements of wearable devices in terms of miniaturization and lightweighting. Acoustically, it can achieve an array element spacing of less than one wavelength, and realize plane wave composite imaging by using the array lower layer interdigitated electrode row circuit addressing design.

[0069] like Figures 6-9 As shown, one embodiment of this study also provides a method for preparing the above-mentioned flexible ultrasonic patch, including the following steps S110-S120:

[0070] S110. An interdigitated electrode layer 200 is provided on one side of the flexible substrate layer 100;

[0071] S120. A piezoelectric layer 300 is provided on the side of the interdigitated electrode layer 200 that is away from the flexible substrate layer 100.

[0072] S130, A mesh electrode layer 400 is provided on the side of the piezoelectric layer 300 away from the interdigitated electrode layer 200.

[0073] The flexible ultrasonic patch prepared by the above method can achieve a dense flexible ultrasonic phased array at the sub-millimeter scale. This flexible ultrasonic patch can meet the curvature changes of the skin surface such as the human chest cavity, and meets the requirements of wearable devices in terms of miniaturization and lightweighting. Acoustically, it can achieve an array element spacing of less than one wavelength, and realize plane wave composite imaging by using the addressing design of the array lower layer interdigitated electrode row circuit.

[0074] like Figure 1 and Figure 2 As shown, in some embodiments, the step of forming the interdigitated electrode layer 200 on one side of the flexible substrate layer 100 includes S111-S113:

[0075] S111. The first electrode material layer 200' is attached to the flexible substrate layer 100.

[0076] The flexible substrate layer 100 has a thickness of 55 μm-60 μm. The first electrode material layer 200' has a thickness of 10 μm-11 μm. In a specific example, the flexible substrate layer 100 has a thickness of 55 μm-60 μm. The first electrode material layer 200' has a thickness of 20 μm.

[0077] The flexible substrate layer 100 is a polyimide film. The first electrode material layer 200' is a copper film. It should be noted that the flexible substrate layer 100 is not limited to the above-mentioned film layer, and can also be other flexible materials, such as an elastic hydrogel film. The first electrode material layer 200' is not limited to the above-mentioned film layer, and can also be other electrode materials, such as a conductive metal film such as gold or silver.

[0078] Specifically, the steps of S111 include: bonding a 60μm polyimide film to a 20μm copper film, and then cutting the bonded film into 20×20mm squares.

[0079] S113. The interdigitated electrode layer 200 is formed by micro-machining on the first electrode material layer 200' using laser direct etching process.

[0080] The step of forming the interdigitated electrode layer 200 by micromachining on the first electrode material layer 200' using laser direct etching technology includes: micromachining the first electrode material layer 200' using a laser direct etching system to form N interdigitated guide lines 210 with opposite first and second ends and 2N circuit pins 220. The N interdigitated guide lines 210 are arranged side by side and spaced apart. The first ends of each interdigitated guide line 210 are connected to form a first connection point 211, and the second ends of each interdigitated guide line 210 are connected to form a second connection point 213. The N circuit pins 220 are arranged side by side and spaced apart and connected to the first connection point 211. The remaining N electrode pins are arranged side by side and connected to the second connection point 213, thus obtaining the interdigitated electrode layer 200.

[0081] For a detailed description of the interdigitated electrode layer 200, please refer to the above text, and it will not be repeated here.

[0082] In some embodiments, the length of each insertion guide 210 is 6.5mm-6.7mm, the width of each insertion guide 210 is 0.5mm, and the spacing between two adjacent insertion guides 210 is 0.25mm-0.3mm.

[0083] In one specific example, the spacing between two adjacent insertion guides 210 is 0.3 mm. The length of each insertion guide 210 is 6.7 mm. The width of each insertion guide 210 is 0.5 mm.

[0084] Among them, the laser direct marking system is the laser direct marking system (ProtoLaser U3, LPKF).

[0085] like Figure 3 and Figure 4 As shown, in some embodiments, the step of forming a piezoelectric layer 300 on the side of the interdigitated electrode layer 200 facing away from the flexible substrate layer 100 includes S121-S123:

[0086] S121. The piezoelectric material plate is pasted onto the base film, and the piezoelectric material plate is processed by a dicing machine micro-engraving system to form multiple piezoelectric blocks 310.

[0087] The base film is a UV film. It should be noted that the base film is not limited to a UV film; it can also be other film materials, such as water-soluble adhesive tape.

[0088] Piezoelectric materials are hard, brittle, and difficult to process. The processing requires careful attention to the dimensions of the piezoelectric elements, the spacing between them, and the integrity of the elements. Specifically, steps S121 include: cutting 20×20mm piezoelectric cubes (i.e., piezoelectric material plates with a thickness of 290μm) using a dicing machine (DAD323, DISCO Corporation), and then attaching the piezoelectric cubes to the VU film (film thickness of 0.1mm); cutting the piezoelectric cubes using a 0.1mm cutter at a dicing speed of 1mm / s, resulting in piezoelectric blocks 310 with dimensions of 0.5×0.5mm (length and width); the spacing between four adjacent piezoelectric blocks 310 constitutes the element spacing 320, with an element spacing of 0.3×0.3mm (length and width); and cutting the required piezoelectric blocks 310 along with the VU to the same size as the interdigitated electrodes.

[0089] S123. Using conductive material, each piezoelectric block 310 is bonded to the side of the interdigitated electrode layer 200 away from the flexible substrate layer 100, and the multiple piezoelectric blocks 310 are arranged in an N-row and N-column interval matrix, and each row of piezoelectric blocks 310 covers one interdigitated guide line 210 and is connected to the corresponding interdigitated guide line 210 to form a piezoelectric layer 300.

[0090] The ground wire of the piezoelectric layer 300 is bonded to the insertion guide wire 210.

[0091] The conductive material is conductive silver paste.

[0092] Specifically, step S123 includes: bonding a uniform layer of conductive silver paste to the side of the interdigitated electrode layer 200 facing away from the flexible substrate layer 100, removing the mask, aligning the piezoelectric blocks 310 array, and heating and curing. The specific operation is as follows: the laser-prepared interdigitated electrode layer 200 is laid flat on a clean glass slide, and hot melt adhesive tape is pasted on the polyimide side (i.e., the side of the flexible substrate layer 100 facing away from the interdigitated electrode layer 200); with the copper film side of the interdigitated electrode (i.e., the side of the interdigitated electrode layer 200 facing away from the flexible substrate layer 100) facing upwards, conductive silver paste is evenly applied; the piezoelectric blocks 310 of the same size are aligned according to the interdigitated electrode alignment groove, placed on a constant temperature heating table at 60°C and heated for 30 minutes to cure, and after curing, the hot melt adhesive tape on the polyimide side is removed to form the piezoelectric layer 300.

[0093] like Figure 4 As shown in the example, the piezoelectric material is arranged in an 8×8 matrix. Each row of piezoelectric units is connected to the corresponding row interdigitated electrode through conductive silver paste. Each row electrode has an independent external electrode pin for connecting external leads. The piezoelectric array elements are connected to the common mesh copper film electrode through conductive silver paste.

[0094] like Figures 5-7As shown, in some embodiments, the step of forming a mesh electrode layer 400 on the side of the piezoelectric layer 300 opposite to the interdigitated electrode layer 200 includes S131-S133:

[0095] S131. A mesh electrode layer 400 is formed on the second electrode material layer by laser direct etching process.

[0096] The second electrode material layer is a copper film layer. The thickness of the second electrode material layer is 10 μm.

[0097] Specifically, S131 includes: selecting a flat copper film, cutting a 20×20mm square, pasting it onto a hot melt adhesive tape, preparing the material, placing it into the laser direct engraving system (ProtoLaser U3, LPKF) operating platform for printing processing, forming a mesh electrode layer 400.

[0098] S133. A conductive material is used to bond the mesh electrode layer 400 to the side of the piezoelectric layer 300 away from the interdigitated electrode layer 200, so that each row of piezoelectric blocks 310 can share the mesh electrode layer 400.

[0099] The conductive material is conductive silver paste.

[0100] Specifically, S133 includes: uniformly applying conductive silver paste to the copper film formed after reprocessing, and then centrifuging it in a centrifuge to homogenize the silver paste. After centrifugation, the upper mesh copper film is separated from the adhesive tape. The piezoelectric material array (piezoelectric material signal surface) is aligned with the grooves of the electrodes on the copper film mesh. After being adhered with conductive material, it is pressed firmly with a glass plate and placed on a constant temperature heating table, heated at 60°C for 30 minutes. The centrifuge speed is set to 3000 RPM (corresponding to a centripetal acceleration of 17.5 m / s²), and the centrifugation time is 5 minutes.

[0101] The aforementioned method for fabricating flexible ultrasonic patches utilizes a laser direct etching system (ProtoLaser U3, LPKF) and a dicing micro-etching system (DAD323, DISCO Corporation) to prepare a flexible ultrasonic transducer patch with interdigitated electrodes. This flexible transducer patch comprises a polyimide substrate, lower interdigitated electrodes, a conductive silver paste layer, a piezoelectric layer 300, and a shared upper electrode of a mesh copper film. The laser direct etching system flexibly fabricates submicron-scale interdigitated electrodes and a mesh-structured upper copper film electrode. This circuit design not only achieves element spacing of less than 0.1 mm but also allows for the control of the activation of several array elements through the lower interdigitated electrodes, realizing plane wave composite ultrasonic imaging acoustic functions. The DISCO dicing micro-etching system effectively processes hard and brittle piezoelectric materials at the micron scale, providing element sizes and spacing of less than 0.1 mm while ensuring the uniformity and density of the flexible ultrasonic array units. The lower interdigitated electrode has eight channels. Several processed piezoelectric blocks 310 are bonded to the lower interdigitated electrode by conductive silver paste through a transfer method. The upper layer is bonded to the flexible copper mesh film using conductive silver paste and a shared upper electrode. The flexible ultrasonic patch is encapsulated with silicone to allow the lower interdigitated electrode and the upper flexible copper film electrode to deform synchronously to adapt to complex curved surfaces.

[0102] The above-described preparation method can stably, quickly, and at low cost produce flexible ultrasonic patches with stable acoustic performance.

[0103] The following are specific examples.

[0104] Unless otherwise specified, the drugs and instruments used in the examples are conventional choices in the art. Experimental methods not specifying particular conditions in the examples are typically performed under standard conditions, such as those described in literature, books, or methods recommended by the reagent kit manufacturer.

[0105] Example 1

[0106] 1. Lower intercalation electrode fabricated by laser direct etching system: A 60μm polyimide film and a 20μm copper film are bonded together. After bonding, the film is cut into 20×20mm cubes and placed into a laser direct etching system z (ProtoLaser U3, LPKF) for micro-machining of the lower intercalation electrode. The intercalation electrode consists of two parts: one is that the intercalation electrode consists of 8 intercalation leads and 4 circuit pins distributed on each side. Each lead is spaced 0.3mm apart, 6.7mm long, and 0.5mm wide. The 8 leads are arranged in parallel.

[0107] 2. Upper-layer flexible copper film electrode fabricated by laser direct etching system: The upper-layer flexible copper film electrode is made of 10μm thick copper film. A 20×20mm square of flat copper film is cut and pasted onto hot melt adhesive tape. The material is then placed on the laser direct etching system (ProtoLaser U3, LPKF) platform for printing. After processing, conductive silver paste is evenly applied, and then centrifuged to homogenize the silver paste. After centrifugation, the piezoelectric material array is aligned with the grooves on the copper film mesh electrode, pressed firmly with a glass plate, and placed on a constant temperature heating stage for 60℃ for 30 minutes.

[0108] 3. Micro-scribing of piezoelectric materials: Piezoelectric materials are hard, brittle, and difficult to machine. During processing, attention must be paid to the dimensions of the piezoelectric elements, the spacing between elements, and the integrity of the elements. A dicing machine (DAD323, DISCO Corporation) is used to cut 20×20mm piezoelectric blocks, which are then adhered to the VU film (film thickness 0.1mm). A 0.1mm cutter is used to cut the piezoelectric blocks at a scribing speed of 1mm / s. The resulting piezoelectric blocks are 0.5×0.5mm in size, with an element spacing of 0.3×0.3mm. The required piezoelectric blocks, along with the VU film, are then cut to the same size as the interdigitated electrodes.

[0109] 4. Mask Bonding Process: The bonding process mainly involves bonding the piezoelectric layer to the lower intercalation electrodes and the upper copper mesh electrodes. This process consists of two parts: first, bonding the piezoelectric layer ground lines to the lower intercalation electrodes; second, bonding the piezoelectric layer signal lines to the upper copper mesh electrodes. The specific steps are as follows:

[0110] The laser-prepared interdigitated electrodes are laid flat on a clean glass slide. Hot melt adhesive tape is pasted on the polyimide side of the interdigitated electrodes. The copper film side of the interdigitated electrodes is facing up. Conductive silver paste is evenly applied. The piezoelectric blocks of the same size are aligned with the interdigitated electrode alignment grooves. The blocks are placed on a constant temperature heating table and heated at 60°C for 30 minutes to cure. After curing, the hot melt adhesive tape on the signal side of the piezoelectric material is removed.

[0111] The upper electrode of the laser-micromachined mesh copper film is removed and attached to a hot melt adhesive tape. Conductive silver paste is then evenly applied and the film is placed in a centrifuge. The centrifuge speed is set to 3000 RPM (corresponding to a centripetal acceleration of 17.5 m / s²), and the centrifugation time is 5 minutes. After centrifugation, the upper mesh copper film is separated from the adhesive tape. The mesh copper film electrode is then aligned and bonded to the signal face of the piezoelectric material. The film is then placed on a constant-temperature heating stage at 60°C for 30 minutes to cure, resulting in a row-addressable flexible ultrasonic patch.

[0112] 5. The working mode of the above-mentioned row-addressable flexible ultrasonic patch is as follows:

[0113] One lower electrode of the interdigitated copper film is grounded, and the upper electrode terminal block of the mesh copper film is connected to the signal line, which can excite all the piezoelectric elements on the interdigitated electrodes in that row, such as... Figure 10 As shown;

[0114] All the lower electrode terminals of the interdigitated copper film are grounded, and the upper electrode terminals of the mesh copper film are connected to signal lines, which can excite all piezoelectric elements, such as... Figure 11 As shown.

[0115] The flexible ultrasonic patch and its fabrication method described in this application have the following advantages: The lower interdigitated electrodes and upper mesh copper film electrodes are fabricated using a direct laser etching system (ProtoLaser U3, LPKF), resulting in high processing precision, small fabrication size, and simple and stable process. Acoustically, it ensures that the center-to-center distance of the array elements does not exceed the sub-μm scale, and can even be less than one wavelength, meeting the requirements of acoustic imaging. Structurally, it can achieve large curvature bending with two degrees of freedom, conforming to the complex curved surfaces of the human body to achieve wearable flexibility. Electrically, addressable interdigitated electrodes are superior to those with flexible circuits and can also meet multiple acoustic imaging methods such as plane wave composite imaging.

[0116] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0117] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A flexible ultrasonic patch, characterized in that, include: Flexible substrate layer; An interdigitated electrode layer is disposed on one side of the flexible substrate layer; A piezoelectric layer is disposed on the side of the interdigitated electrode layer opposite to the flexible substrate layer; A mesh electrode layer is disposed on the side of the piezoelectric layer opposite to the interdigitated electrode layer; wherein: The interdigitated electrode layer includes N interdigitated leads with opposite first and second ends, and 2N circuit pins. The N interdigitated leads are arranged side by side and spaced apart. The first ends of each interdigitated lead are connected to form a first connection point, and the second ends of each interdigitated lead are connected to form a second connection point. The N circuit pins are arranged side by side and spaced apart and connected to the first connection point, and the remaining N circuit pins are arranged side by side and connected to the second connection point.

2. The flexible ultrasonic patch according to claim 1, characterized in that, The piezoelectric layer covers N insertion guide lines. The piezoelectric layer includes a plurality of piezoelectric blocks arranged in an N-row and N-column interval matrix. Each row of piezoelectric blocks covers one insertion guide line and is connected to the corresponding insertion guide line.

3. The flexible ultrasonic patch according to claim 2, characterized in that, Each row of piezoelectric blocks is electrically connected to the mesh electrode layer so that each row of piezoelectric blocks shares the mesh electrode layer.

4. The flexible ultrasonic patch according to claim 3, characterized in that, The length and width of the piezoelectric layer are both 20 mm to 25 mm; the thickness of the piezoelectric layer is 290 μm to 300 μm; the length and width of each piezoelectric block are both 0.5 mm; the spacing between four adjacent piezoelectric blocks constitutes an array element spacing, and the length and width of the array element spacing are both 0.25 mm to 0.3 mm.

5. The flexible ultrasonic patch according to claim 1, characterized in that, The flexible ultrasonic patch further includes a first conductive layer, which is disposed between the piezoelectric layer and the N insertion guide wires; And / or, the flexible ultrasonic patch further includes a second conductive layer disposed between the piezoelectric layer and the mesh electrode layer.

6. The flexible ultrasonic patch according to claim 1, characterized in that, The N insertion guide lines are parallel to each other, and adjacent insertion guide lines are spaced apart; Furthermore, the spacing between two adjacent insertion guides is 0.25 mm to 0.3 mm, the length of each insertion guide is 6.5 mm to 6.7 mm, and the width of each insertion guide is 0.5 mm.

7. The flexible ultrasonic patch according to any one of claims 1-6, characterized in that, The flexible substrate layer is a polyimide film, the interdigitated electrode layer is made of copper, and the mesh electrode layer is made of copper. And / or, the thickness of the flexible substrate layer is 55μm to 60μm, the thickness of the interdigitated electrode layer is 15μm to 25μm, and the thickness of the mesh electrode layer is 10μm to 15μm.

8. A method for preparing a flexible ultrasonic patch as described in claim 1, characterized in that, Includes the following steps: An interdigitated electrode layer is disposed on one side of the flexible substrate layer; A piezoelectric layer is disposed on the side of the interdigitated electrode layer opposite to the flexible substrate layer; A mesh electrode layer is provided on the side of the piezoelectric layer opposite to the interdigitated electrode layer.

9. The preparation method according to claim 8, characterized in that, The step of forming an interdigitated electrode layer on one side of the flexible substrate layer includes: A first electrode material layer is attached to the flexible substrate layer; The interdigitated electrode layer is formed by micromachining on the first electrode material layer using a laser direct etching process.

10. The preparation method according to claim 9, characterized in that, The step of forming the interdigitated electrode layer by micromachining on the first electrode material layer using laser direct etching includes: micromachining the first electrode material layer using a laser direct etching system to form N interdigitated leads with opposite first and second ends, and 2N circuit pins. The N interdigitated leads are arranged side by side and spaced apart. The first ends of each interdigitated lead are connected to form a first connection point, and the second ends of each interdigitated lead are connected to form a second connection point. The N circuit pins are arranged side by side and spaced apart and connected to the first connection point, and the remaining N circuit pins are arranged side by side and connected to the second connection point, thus obtaining the interdigitated electrode layer.

11. The preparation method according to claim 10, characterized in that, The step of forming a piezoelectric layer on the side of the interdigitated electrode layer opposite to the flexible substrate layer includes: A piezoelectric material plate is attached to a base film, and a dicing machine micro-engraving system is used to process the piezoelectric material plate to form multiple piezoelectric blocks; Each piezoelectric block is bonded to the side of the interdigitated electrode layer away from the flexible substrate layer using a conductive material, and the piezoelectric blocks are arranged in an N-row and N-column interval matrix, with each row of piezoelectric blocks corresponding to and covering one interdigitated electrode line and connected to the corresponding interdigitated electrode line to form the piezoelectric layer.

12. The preparation method according to claim 11, characterized in that, The step of setting a mesh electrode layer on the side of the piezoelectric layer opposite to the interdigitated electrode layer includes: The mesh electrode layer is formed by micro-machining on the second electrode material layer using a laser direct etching process; The mesh electrode layer is bonded to the side of the piezoelectric layer away from the interdigitated electrode layer using a conductive material, so that each row of piezoelectric blocks shares the mesh electrode layer.

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