Flexible ultrasonic patch for skin acoustic impedance matching and preparation method thereof

Abstract

The invention provides a skin acoustic impedance matching flexible ultrasonic patch and a preparation method thereof, and the preparation method comprises the following steps: preparing an ultrasonic array on a skin acoustic impedance matching flexible substrate, placing each functional unit at a preset position of the substrate, and printing an electrode wire on the substrate through conductive ink to connect each functional unit; spin-coating the packaging material on the surface of the skin acoustic impedance matching substrate, and curing in a drying oven; an ultrasonic adhesion coupling layer is prepared and cured on the skin surface, and an ultrasonic patch is tightly attached to the coupling layer. The electrode wires printed through ink can be seamlessly attached to the substrate, so that the flexible ultrasonic patch is not broken in the bending and stretching process to adapt to skin wrinkles or bending. The flexible ultrasonic patch can transmit and receive ultrasonic signals, and has wide application prospects in the fields of ultrasonic imaging, physiological monitoring and the like.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic technology, and in particular to a flexible ultrasonic patch for skin acoustic impedance matching and a preparation method thereof. Background Art

[0002] Medical imaging modalities such as magnetic resonance, computed tomography, ultrasound and positron emission tomography are crucial in monitoring, diagnosis and treatment. Medical imaging devices and systems are designed for the diagnosis, prevention and treatment of diseases. Conventional medical imaging devices are bulky and rigid, so their use in continuous monitoring and diagnosis applications is almost unfeasible.

[0003] The ultrasound patch is thin and compact and can be worn directly on the body, while image data is transmitted to mobile or personal devices in real time through cloud storage and machine learning analysis, enabling medical imaging and health monitoring, allowing patients to perform disease diagnosis and health assessment anytime and anywhere. The ultrasound patch can be comfortably attached to the skin and body to continuously image for real-time diagnosis and monitoring.

[0004] Therefore, ultrasound patches attached to the skin need to meet several basic requirements, including: 1) biocompatibility to ensure safety for clinical use; 2) soft and easy to fit different areas of the body, comfortable to the skin to reduce irritation; 3) high mechanical durability, and stable electronic circuits during thousands of deformation cycles; 4) matching the acoustic impedance of the skin to improve the quality of the ultrasound signal; 5) high stability to keep the position fixed during the signal measurement process. 6) The coupling layer has high water retention to ensure long-term monitoring of the signal by the ultrasound patch. Summary of the invention

[0005] The purpose of the present invention is to provide a flexible ultrasonic patch with acoustic impedance matching and a preparation method thereof, which can adapt to different body parts and simultaneously match the acoustic impedance of the skin to achieve high-quality transmission of ultrasonic signals, so as to solve the problems encountered in the above-mentioned background technology.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A flexible ultrasonic patch for skin acoustic impedance matching comprises a skin acoustic impedance matching flexible substrate and an ultrasonic array arranged on the outer surface of the skin acoustic impedance matching flexible substrate, a transmitting / receiving switch, a signal processing unit, a control unit, a pulse generator, a Bluetooth module and a battery, wherein the battery is connected to the control unit and supplies power to the entire device; the control unit controls the pulse generator to send an electric pulse to the ultrasonic array, the ultrasonic array transmits an ultrasonic signal and receives an echo signal at the same time, and the echo signal sends the data to a terminal through the Bluetooth module after passing through the transmitting / receiving switch and the signal processing unit.

[0008] Preferably, it also includes a packaging layer, through which the ultrasound array, transmit / receive switch, signal processing unit, control unit, pulse generator, Bluetooth module, battery and vertical conductive tape are integrated into a structure on the surface of a flexible substrate with skin acoustic impedance matching, thereby preventing each functional unit from directly contacting the external environment, reducing the breakage rate and improving the durability of the ultrasound patch.

[0009] Preferably, an ultrasonic adhesion coupling layer is also included, one side of which is connected to the inner side of the flexible substrate for skin acoustic impedance matching, and the other side is used to be fixed on the skin. The ultrasonic adhesion coupling layer is used to closely fit the patch to the human skin, prevent the ultrasonic patch from shifting during the measurement process, and improve the stability of the ultrasonic patch. At the same time, the coupling layer has high water retention, ensuring the long-term monitoring capability of the signal.

[0010] Preferably, the transmit / receive switch is used to control the transmission and reception of ultrasonic signals; the signal processing unit includes a high-pass filter circuit, an ultrasonic amplifying circuit, and an analog-to-digital conversion circuit; the high-pass filter circuit is used to filter out power frequency interference and motion artifacts; the ultrasonic amplifying circuit is used to amplify the ultrasonic signal; the analog-to-digital conversion circuit is used to perform analog-to-digital conversion on the ultrasonic signal; and the Bluetooth module is used to send the collected ultrasonic data to a terminal (such as a host computer or a mobile phone).

[0011] Preferably, the ultrasonic array is composed of multiple ultrasonic transducers arranged in an array. The ultrasonic transducer includes a piezoelectric ceramic sheet and an electrode layer distributed on both sides of the piezoelectric ceramic sheet. The piezoelectric ceramic sheet converts electrical pulses into high-frequency vibrations and generates ultrasonic waves. It can also respond to ultrasonic echoes and convert them into echo signals, thereby realizing the transmission and reception of ultrasonic signals.

[0012] A method for preparing a flexible ultrasonic patch with acoustic impedance matching comprises the following steps:

[0013] The piezoelectric ceramic sheet and the upper and lower electrode sheets are assembled into an ultrasonic transducer and arranged at designated positions into an ultrasonic array, which is used to transmit and receive ultrasonic signals.

[0014] A flexible substrate that matches the acoustic impedance of the skin is prepared by doping liquid metal with silicon-based materials, and various functional units are placed on the surface of the flexible substrate, including: ultrasound array, pulse generator, control unit, transmit / receive switch, signal processing unit, battery, and Bluetooth module; electrode wires are printed at designated positions using conductive ink to connect the various functional units; and organic materials with insulating and biocompatible properties are spin-coated on the surface of the flexible substrate to encapsulate the various functional units and electrode wires.

[0015] Furthermore, the piezoelectric ceramic sheet is made of one of lead zirconate titanate, aluminum oxide, barium titanate, and barium titanium niobate, and is used after high voltage polarization. The piezoelectric ceramic sheet is connected to the upper and lower electrode layers by soldering with solder paste to obtain a single ultrasonic transducer, and the upper and lower electrode layers of the ultrasonic transducer are not conductive.

[0016] Method for preparing a flexible substrate with skin acoustic impedance matching: Ecoflex 00-30A glue and B glue are mixed in a mass ratio of 1:1, and after stirring evenly, a flexible substrate with uniform thickness and equivalent to the skin acoustic impedance is prepared by vacuum degassing, casting and other methods.

[0017] Furthermore, epoxy resin is mixed with metal powder to prepare a matching layer, so that the acoustic impedance of the skin, the flexible substrate and the ultrasonic transducer is balanced, thereby improving the high-quality transmission of the ultrasonic signal. The metal powder is cerium oxide.

[0018] The method for making electrode wires based on conductive ink is as follows: liquid metal gallium-indium alloy is added to anhydrous ethanol for ultrasonic treatment, and then centrifuged to obtain liquid metal pellets; the liquid metal pellets are dissolved in an isopropanol solution, and carbon nanotubes are added, and finally the conductive ink is obtained by magnetic stirring. The electrode wires printed by the conductive ink can adapt to the mechanical properties of the flexible substrate, so that the electrode wires of the ultrasonic patch will not break when stretched or bent, ensuring the long-term wearability and comfort of the ultrasonic patch.

[0019] Preparation method of ultrasonic adhesion coupling layer: β-(acryloyloxy) propionic acid, water, crosslinking agent and photoinitiator are mixed in a mass ratio of 100:200:0.5:2 and ultrasonically treated until completely dissolved. The solvent is dripped onto the skin surface using a mold and cured by ultraviolet light for 30 seconds to form an ultrasonic adhesion coupling layer.

[0020] Compared with the prior art, the beneficial effects of the present invention are: the flexible ultrasonic patch can be stably and conformably attached to different positions of the human body for a long time, transmit and receive ultrasonic signals through the ultrasonic array, and transmit data to a terminal (such as a mobile phone, a host computer, etc.) through a series of circuits, while matching the acoustic impedance of the skin, improving the energy transfer efficiency, and reducing the signal distortion caused by the mismatch of acoustic impedance. Therefore, compared with the prior art, the flexible ultrasonic patch can be attached to the body surface for a long time to achieve high-quality and stable transmission and reception of ultrasonic signals.

[0021] The present invention uses a polyelectrolyte with bottle brush-like side chains as the ultrasonic adhesion coupling layer, and the polymer side chains have a wide range of polar groups, namely, ester groups and carboxyl groups in β-(acryloyloxy) propionic acid. The bottle brush-like side chains are used to achieve a balance between steric hindrance and the proportion of polar groups, thereby achieving high water retention and low modulus.

[0022] By introducing carboxyl groups on the side chains, covalent bonds are formed with amino groups on the surface of skin tissue, thereby improving the adhesion between the device and the tissue. In addition, polyelectrolytes can also be formed in situ on the tissue surface by in situ curing (photoinitiation or thermal initiation), further improving the adhesion between the device and the tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The disclosure of the present invention is described with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components. Among them:

[0024] Figure 1 Block diagram of the flexible ultrasound patch system for skin acoustic impedance matching;

[0025] Figure 2 A schematic diagram of the structure of a flexible ultrasound patch for skin acoustic impedance matching;

[0026] Figure 3 This is a schematic diagram of the structure of an ultrasonic array introduced in an embodiment of the present invention;

[0027] Figure 4 Schematic diagram of integrated packaging of flexible ultrasound patch for skin acoustic impedance matching;

[0028] Figure 5 This is a schematic diagram of the structure of the conductive ink introduced in the embodiment of the present invention;

[0029] Figure 6 This is a waveform diagram of an ultrasonic signal emitted by one example of the flexible ultrasonic patch introduced in the embodiment of the present invention;

[0030] Figure 7 This is a waveform diagram of an ultrasonic signal received by one example of the flexible ultrasonic patch introduced in the embodiment of the present invention;

[0031] Figure 8 The stress-strain curve of the adhesion coupling layer introduced in the embodiment of the present invention;

[0032] Fig. 9 This is a curve showing the change of water retention of the adhesion coupling layer over time introduced in an embodiment of the present invention;

[0033] Fig.10 This is a schematic diagram of acoustic impedance obtained by mixing different materials in the matching layer of the flexible patch according to an embodiment of the present invention;

[0034] Explanations in the figure: 1. Ultrasonic adhesion coupling layer; 2. Skin acoustic impedance matching flexible substrate; 3-ultrasonic array; 31-ultrasonic transducer; 311-electrode layer; 312-piezoelectric ceramic sheet; 4. Transmit / receive switch; 5. Signal processing unit; 6. Control unit; 7. Pulse generator; 8. Bluetooth module; 9. Battery; 10. Packaging layer; 11. Vertical conductive tape. DETAILED DESCRIPTION

[0035] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the present invention is now further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the relevant components of the present invention.

[0036] According to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and the accompanying drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the entirety of the present invention or as a limitation or restriction to the technical solution of the present invention.

[0037] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0038] Example 1

[0039] See also Figure 1 and Figure 2 A flexible ultrasound patch for skin acoustic impedance matching includes a skin acoustic impedance matching flexible substrate 2, an ultrasound array 3 arranged on the surface of the skin acoustic impedance matching flexible substrate 2, a transmitting / receiving switch 4, a signal processing unit 5, a control unit 6, a pulse generator 7, a Bluetooth module 8 and a battery 9, and the functional units are interconnected by wires. The battery 9 supplies power to the entire ultrasound patch through the control unit 6.

[0040] The flexible ultrasonic patch also includes a packaging layer 10, through which the ultrasonic array 3, the transmitting / receiving switch 4, the signal processing unit 5, the control unit 6, the pulse generator 7, the Bluetooth module 8, the battery 9 and the vertical conductive tape 11 are integrated on the surface of the acoustic impedance matching flexible substrate 2 to prevent the functional units from directly contacting the external environment, reduce the breakage rate, and improve the durability of the ultrasonic patch.

[0041] The flexible ultrasonic patch is also equipped with an ultrasonic adhesive coupling layer 1, which can closely fit the human skin, prevent the ultrasonic patch from shifting during the measurement process, and improve the stability of the ultrasonic patch. At the same time, the coupling layer has high water retention, ensuring the long-term monitoring capability of the signal.

[0042] The flexible substrate 2 is made of an organic material that matches the acoustic impedance of the skin, at least one of polyvinyl alcohol, polylactic acid, silicone rubber, and polyester, and is prepared into a film by spin coating, pouring, spraying, coating, or calendering.

[0043] The ultrasonic array 3 is connected to the transmitting / receiving switch 4 and the pulse generator 7. When it is necessary to transmit an ultrasonic signal, the control unit 5 controls the pulse generator 7 to transmit an electric pulse to the ultrasonic array 3, thereby generating an ultrasonic wave. The transmitting / receiving switch 4 controls the transmitting channel and the receiving channel of the ultrasonic array 3. The transmitting mode transmits an ultrasonic signal, and the receiving mode receives an echo signal. The echo signal channel is controlled by the transmitting / receiving switch, and then sent to the signal processing unit 5. After filtering, amplification, and analog-to-digital conversion, the voice data is transmitted to the terminal through the Bluetooth module 8. The transmitting and receiving signals of the ultrasonic array 3 are not synchronous, and the operating mode needs to be switched by the transmitting / receiving switch. Generally, it is first switched to the transmitting mode to transmit the ultrasonic signal, and then switched to the receiving mode to receive the echo signal. Since the transmitted signal is a pulse signal, the transmission and reception of the ultrasonic signal can be completed within one cycle.

[0044] Example 2

[0045] See also Figure 3 to Figure 4 This embodiment introduces a method for preparing a flexible ultrasound patch with skin acoustic impedance matching, which mainly includes an ultrasound array 3, a skin acoustic impedance matching flexible substrate 2, a functional unit and a packaging layer 10 arranged in sequence, so the steps of the preparation method are as follows:

[0046] Step 1: Prepare the ultrasonic array. UV ozone surface activation was performed on the polydimethylsiloxane film and the copper film for 3 minutes. The free radicals and active oxygen molecules generated by ozone decomposition reacted chemically with the surface of the material, allowing the two to bond together.

[0047] Furthermore, the copper film is marked by a laser marking machine to carve out the circuit patterns of the upper and lower electrodes of the ultrasonic array, and the excess copper film is peeled off to obtain the electrode circuit 311 of the ultrasonic array.

[0048] Step 2: Prepare a flexible substrate for skin acoustic impedance matching. Mix Ecoflex00-30 A glue and B glue in a mass ratio of 1:1, stir for 5 minutes, put into a vacuum drying oven, place under negative pressure for 10 minutes to remove bubbles, take out and put into an oven for curing for 30 minutes. Mix epoxy resin (EPOXY-301), cerium oxide powder and curing agent in a mass ratio of 4:4:1, stir for 10 minutes, pour into a concave mold and put into an oven for heating for 1 hour to obtain a matching layer. After curing, the matching layer is directly attached to the flexible substrate.

[0049] The acoustic impedance of the matching layer can be adjusted by the specific gravity of cerium oxide powder. The influence of different specific gravity of cerium oxide powder on acoustic impedance is as follows: Fig.10As shown in the figure, the increase in the specific gravity of cerium oxide will increase the acoustic impedance of the matching layer. Considering the mixing and fusion of cerium oxide powder and epoxy resin and the acoustic impedance, a 1:1 mass ratio of cerium oxide to epoxy resin was finally selected to prepare the matching layer, thereby achieving the matching of the acoustic impedance between the skin, substrate and ultrasonic transducer.

[0050] Step 3: Transfer the electrode circuit of the ultrasound array to the skin acoustic impedance matching flexible substrate through a water-soluble tape, and dissolve the water-soluble tape with deionized water.

[0051] Furthermore, a mask plate with four square holes is fixed to the corresponding position on the surface of the flexible substrate, and the square holes are aligned with the small dots in the electrode circuit. First, solder paste is dripped on the small dots in the square holes, and the piezoelectric ceramic sheet 312 is placed in the corresponding position with tweezers, and cured at 70°C for 30 minutes. The piezoelectric ceramic sheet is selected from one of lead zirconate titanate, aluminum oxide, barium titanate, and barium titanium niobate.

[0052] Furthermore, solder paste is dripped onto the upper surface of the piezoelectric ceramic sheet 312, and another electrode circuit is placed directly above the piezoelectric ceramic sheet 312. The product is also cured at 70°C for 30 minutes to obtain an ultrasonic transducer 31. In this embodiment, an ultrasonic array is composed of four ultrasonic transducers 31, and the number of ultrasonic transducers can be further increased according to actual applications.

[0053] Furthermore, an uncured matching layer solution was dripped onto the upper electrode circuit, and the cured matching layer was placed on the electrode and cured at 70° C. for 1 hour.

[0054] Step 4: Figure 4 As shown, each functional unit is adhered to a preset position of the skin acoustic impedance matching flexible substrate 2, and each functional unit is connected with a conductive material according to a corresponding circuit. The conductive material can be one of silver paste, graphite, and conductive polymer.

[0055] The functional unit includes a transmitting / receiving switch, a signal processing unit, a control unit, a pulse generator, a Bluetooth module and a battery. The signal processing unit 6 includes an amplification circuit, a high-pass filter circuit, and an analog-to-digital conversion circuit. The signal processing unit 6 further processes the ultrasonic echo signal collected by the ultrasonic array and transmits this data to a terminal, such as a mobile phone, a host computer, etc., through the Bluetooth module 8.

[0056] The entire device is powered by the battery 9, which is a button cell, a lithium battery or a flexible supercapacitor.

[0057] It should be noted that the thickness of the flexible ultrasonic patch does not exceed 2 mm, so that the flexible ultrasonic patch can better fit the skin.

[0058] Step 5: Coat a layer of the encapsulation layer 10 on the surface of the device prepared above to protect each unit and circuit.

[0059] The specific method is: the encapsulation layer material is epoxy resin, and it is mixed with epoxy resin special curing agent at a mass ratio of 10:1, stirred with a glass rod for 5 minutes to make it evenly mixed, and then the bubbles in the solution are removed by a centrifuge for subsequent use. The prepared epoxy resin is spin-coated on the surface of the ultrasound patch and cured in a 60°C oven for 2 hours.

[0060] Step 6: Prepare the ultrasonic adhesion coupling layer. Mix β-(acryloyloxy)propionic acid (CAS No.: 24615-84-7), water, crosslinker (N,N'-methylenebisacrylamide) and photoinitiator (phenyl-2,4,6-trimethylbenzoyl lithium phosphite) in a mass ratio of 100:200:0.5:2, and ultrasonically treat for 5 minutes until completely dissolved. Use a mold to drop the prepared solvent on the skin surface and cure it under ultraviolet light for 30 seconds to form an ultrasonic adhesion coupling layer. The stress and water retention of the ultrasonic adhesion coupling layer were tested, and the results are as follows: Figure 8 and Fig. 9 shown.

[0061] In this embodiment, a flexible substrate for skin acoustic impedance matching is prepared, and various functional units are integrated on the surface of the substrate, and the flexible ultrasonic patch is obtained by further packaging, and then the flexible ultrasonic patch is transferred to the ultrasonic adhesion coupling layer.

[0062] Example 3

[0063] This embodiment introduces another method for preparing a flexible ultrasound patch with skin acoustic impedance matching, which also includes an ultrasound array, a functional unit, and a packaging layer arranged in sequence. The specific steps are as follows:

[0064] Step 1: Apply solder paste on one side of the two electrode sheets and stick them on both sides of the piezoelectric ceramic sheet, and then heat treat them on a hot plate at 70°C for 2 hours. The piezoelectric ceramic sheet can be one of lead zirconate titanate, aluminum oxide, barium titanate, and barium titanium niobate.

[0065] The prepared piezoelectric transducers are placed on a flexible substrate and arranged into an ultrasonic array at designated positions, and the number of piezoelectric transducers is greater than or equal to 4. The flexible substrate is prepared as in Example 2, and is matched with the acoustic impedance of the skin to increase the energy transfer efficiency.

[0066] It should be noted that the piezoelectric ceramic sheets used have undergone high-voltage polarization operations and have good piezoelectric properties.

[0067] Step 2: Place each functional unit on the flexible substrate at a preset position, and prepare an electrode circuit by printing conductive ink to connect each functional unit.

[0068] Preparation method of conductive ink: Figure 5 As shown, 2 grams of liquid metal gallium-indium alloy was added to 5 milliliters of anhydrous ethanol, and after ultrasonic treatment in a cold water bath for 1 hour, the solution was centrifuged to separate liquid metal spheres; the liquid metal spheres were dissolved in an isopropanol solution, and a certain amount of carbon nanotubes were added, and conductive ink was obtained after magnetic stirring. The conductive ink was placed in a 10-ml syringe for subsequent use.

[0069] It should be noted that during the printing of the conductive ink, the distance between the nozzle tip and the flexible substrate was maintained at 1 mm.

[0070] The third step: encapsulate the surface of the flexible ultrasonic patch. On the one hand, it fixes each functional unit to make it integrated and improve the mechanical strength. On the other hand, it prevents the device from direct contact with the outside world and protects each functional unit.

[0071] Step 4: Transfer the packaged flexible ultrasonic patch to the ultrasonic adhesion coupling layer to prevent the patch from shifting during signal monitoring and improve stability.

[0072] The flexible ultrasonic patch introduced in the embodiment of the present invention can realize the functions of transmitting and receiving ultrasonic signals. Figure 6 and Figure 7 3 is a waveform diagram of the transmitted and received ultrasonic signals of Example 3.

[0073] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flexible ultrasound patch with skin acoustic impedance matching, characterized in that: The device comprises a skin acoustic impedance matching flexible substrate (2), an ultrasonic array (3) arranged on the outer surface of the skin acoustic impedance matching flexible substrate (2), a transmitting / receiving switch (4), a signal processing unit (5), a control unit (6), a pulse generator (7), a Bluetooth module (8) and a battery (9), wherein the battery (9) is connected to the control unit (6) and supplies power to the entire device; the control unit (6) controls the pulse generator (7) to send electric pulses to the ultrasonic array (3), the transmitting / receiving switch (4) controls the ultrasonic array (3) to transmit ultrasonic signals, and receives echo signals, transmits the received echo signals to the signal processing unit (5) for processing, and then sends the data to the terminal via the Bluetooth module (8).

2. The flexible ultrasound patch with skin acoustic impedance matching according to claim 1, characterized in that: The invention also comprises a packaging layer (10), through which the ultrasound array (3), the transmitting / receiving switch (4), the signal processing unit (5), the control unit (6), the pulse generator (7), the Bluetooth module (8), the battery (9) and the vertical conductive tape (11) are integrated on one side of the surface of the skin acoustic impedance matching flexible substrate (2) to form an integrated structure, and the other side of the skin acoustic impedance matching flexible substrate (2) is exposed.

3. A flexible ultrasound patch for skin acoustic impedance matching according to claim 1 or 2, characterized in that: It also comprises an ultrasonic adhesion coupling layer (1), one side of the ultrasonic adhesion coupling layer (1) is connected to the skin acoustic impedance matching flexible substrate (2), and the other side is used to be fixed on the skin.

4. The flexible ultrasound patch for skin acoustic impedance matching according to claim 1, characterized in that: The transmitting / receiving switch (4) is used to control the transmission and reception of ultrasonic signals; the signal processing unit (5) comprises a high-pass filtering circuit, an ultrasonic amplifying circuit, and an analog-to-digital conversion circuit; the high-pass filtering circuit is used to filter out power frequency interference and motion artifacts; the ultrasonic amplifying circuit is used to amplify the ultrasonic signal; the analog-to-digital conversion circuit is used to perform analog-to-digital conversion on the ultrasonic signal; and the Bluetooth module is used to send the collected ultrasonic data to a terminal.

5. The flexible ultrasound patch with skin acoustic impedance matching according to claim 1, characterized in that: The ultrasonic array (3) is composed of a plurality of ultrasonic transducers (31) arranged in an array. The ultrasonic transducers (31) include a piezoelectric ceramic sheet (312) and electrode layers (311) distributed on both sides of the piezoelectric ceramic sheet (312). The piezoelectric ceramic sheet converts electrical pulses into high-frequency vibrations and generates ultrasonic waves. It can also respond to ultrasonic echoes and convert them into echo signals, thereby realizing the transmission and reception of ultrasonic signals.

6. The flexible ultrasound patch for skin acoustic impedance matching according to any one of claims 1 to 5, characterized in that: The ultrasonic adhesion coupling layer (1) is prepared by mixing β-(acryloxy) propionic acid with a crosslinking agent and a photoinitiator and then irradiating the mixture with ultraviolet light.

7. A method for preparing a flexible ultrasonic patch with skin acoustic impedance matching according to any one of claims 1 to 6, characterized in that: The following steps are involved: An ultrasonic array is prepared by using a piezoelectric ceramic sheet and transferred to a flexible substrate matching the skin acoustic impedance, wherein the ultrasonic array is used to transmit and receive ultrasonic signals; Various functional units are placed on the surface of the skin acoustic impedance matching flexible substrate, including: an ultrasound array, a transmitting / receiving switch, a signal processing unit, a control unit, a pulse generator, a Bluetooth module and a battery block; Printing electrode wires with conductive ink to connect various functional units; An insulating and biocompatible organic material is spin-coated on the surface of a flexible substrate that matches the skin acoustic impedance to encapsulate various functional units and electrode wires. The packaged flexible ultrasound patch is transferred to the ultrasound adhesion coupling layer.

8. The method for preparing a flexible ultrasonic patch with skin acoustic impedance matching according to claim 7, characterized in that: The piezoelectric ceramic sheet is made of one of lead zirconate titanate, aluminum oxide, barium titanate, and barium titanium niobate, and is connected with two electrode sheets by soldering with solder paste to obtain the piezoelectric transducer.

9. The method for preparing a flexible ultrasonic patch with skin acoustic impedance matching according to claim 7, characterized in that: The skin acoustic impedance matching flexible substrate (2) is made of Ecoflex 00-30, and the acoustic impedance matching layer is made by mixing epoxy resin and cerium oxide.

10. The method for preparing a flexible ultrasonic patch with skin acoustic impedance matching according to claim 7, characterized in that: The ultrasonic adhesion coupling layer is prepared by mixing beta-(acryloxy) propionic acid with a crosslinking agent and a photoinitiator and then crosslinking the mixture.

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