A flexible wearable patch

Abstract

The application discloses a flexible wearable patch, which comprises a flexible ultrasonic transducer and a flexible stretchable electrode which is pasted to the flexible ultrasonic transducer; the flexible ultrasonic transducer comprises a flexible backing layer, a first flexible printed circuit board layer and a flexible acoustic stack layer which are sequentially stacked; the area of the first flexible printed circuit board layer which is not provided with the flexible acoustic stack layer is pasted to the flexible stretchable electrode; the flexible wearable patch further comprises a second flexible printed circuit board layer; and the flexible stretchable electrode is electrically connected to the second flexible printed circuit board layer. The flexible wearable patch provided by the application integrates ultrasonic imaging and electrical signal monitoring, and can realize synchronous in-situ monitoring of ultrasonic imaging and electrical signals.

Description

Technical Field

[0001] The present invention belongs to the field of bio-interface sensing technology, and in particular relates to a flexible wearable patch. Background Art

[0002] Neuromuscular diseases (NMDs) cause muscle weakness and movement disorders. Traditional diagnostic methods, such as electromyography (EMG) and ultrasound imaging, primarily target different aspects of muscle function but fail to provide a comprehensive assessment. EMG monitors the electrophysiological activity of muscles, while ultrasound imaging provides structural information. Despite recent advances in flexible electronics in both areas, existing technologies still face numerous challenges, such as unstable contact caused by skin deformation, signal synchronization issues, and the inability of existing devices to meet the needs of long-term, dynamic monitoring.

[0003] For electrophysiological signal monitoring, current research focuses on flexible electrode arrays, particularly those based on highly flexible materials such as flexible stretchable films and ion gels. These materials can effectively adapt to skin deformation, reduce contact problems caused by movement or muscle contraction, and ensure signal stability. Furthermore, research on biomimetic three-dimensional electronic skin demonstrates the potential for building complex flexible sensing systems through decoupled sensing capabilities. These systems mimic the spatial distribution of mechanoreceptors in human skin, further improving the accuracy and functionality of wearable sensors.

[0004] When it comes to ultrasound imaging technology, commercial ultrasound equipment is usually rigid and bulky, making it unsuitable for long-term, continuous, and stable monitoring. Typically, users must hold the rigid ultrasound device and apply a certain amount of pressure to ensure good contact with the skin to obtain clear tissue imaging. Although this method performs well in deep tissue imaging, applying pressure may cause muscle deformation, thereby affecting the accurate reflection of the true structural characteristics when imaging the muscle. Therefore, the research focus has gradually shifted to the development of flexible, stretchable ultrasound probes to replace traditional rigid probes for blood pressure, blood flow detection, and structural imaging. These sensors can adapt to the skin surface and achieve dynamic imaging, and are particularly suitable for muscle structural monitoring. However, existing ultrasound imaging technology often faces the problem of skin deformation affecting imaging quality, especially during dynamic movement, the imaging quality will be subject to certain limitations.

[0005] Furthermore, unilateral assessments based solely on structural or functional monitoring often yield incomplete information and may even lead to misdiagnosis. Overall, existing technologies lack effective integration of electrophysiological and ultrasound imaging, limiting comprehensive diagnosis and monitoring of muscle health. Consequently, a dual-modal flexible sensing patch that can simultaneously detect electrophysiological signals and changes in muscle structure is lacking.

[0006] In existing technologies, electrophysiological monitoring and ultrasound imaging are usually performed separately to detect functional muscle signals (such as electromyography) and structural muscle signals (such as muscle thickness and morphology), respectively. However, this single-modality monitoring has the following key issues:

[0007] (1) Lack of dual-modal synchronous monitoring: Most existing technologies can only obtain electrophysiological signals or ultrasound images separately, and cannot simultaneously monitor electrophysiological and ultrasound signals in real time. This means that it is impossible to directly obtain muscle structure and function information in situ, resulting in an incomplete comprehensive assessment of disease or health status, affecting the accuracy of diagnosis. If directly combined, the system will be large and difficult to wear, and will be too rigid and not conform to dynamically deformed skin, making imaging difficult.

[0008] (2) Impact of skin deformation on monitoring accuracy: When the human body moves or the skin stretches, electrophysiological electrodes are easily affected by skin deformation, resulting in signal distortion. At the same time, traditional ultrasound equipment requires relatively stable contact. Long-term wearing or dynamic movement will affect the accuracy of the ultrasound signal. Existing technologies cannot effectively maintain signal stability and reliability during dynamic movement, especially when skin deformation exceeds a certain range.

[0009] (3) Lack of integrated design and compatibility: Currently, electrophysiological electrodes and ultrasound sensors are often operated independently during use and cannot be effectively integrated. In order to achieve the best monitoring effect, multiple devices need to be used simultaneously, which not only increases the complexity of operation but also limits the portability and comfort of the system. Especially in scenarios that require long-term wear and dynamic monitoring, existing technologies cannot meet the requirements for integration, flexibility, and stability. Summary of the Invention

[0010] In response to the above technical problems, the present invention provides a flexible wearable patch that integrates a flexible ultrasonic transducer (FUT) and a flexible stretchable electrode. While maintaining high-quality imaging, the patch improves the overall wearability of the device, making it more suitable for long-term wear. At the same time, it ensures the stability of electromyographic signal acquisition, reduces the impact of deformation on ultrasonic transducer imaging, and makes the entire system have good flexibility and fit.

[0011] To achieve the above object, the technical solution of the present invention is as follows:

[0012] The present invention provides a flexible wearable patch, comprising a flexible ultrasonic transducer and a flexible stretchable electrode adhesively connected thereto;

[0013] The flexible ultrasonic transducer comprises a flexible backing layer, a first flexible printed circuit board layer, and a flexible acoustic stack layer provided on the first flexible printed circuit board layer, which are stacked in sequence; an area on the first flexible printed circuit board layer where the flexible acoustic stack layer is not provided is adhesively connected to a flexible stretchable electrode;

[0014] The flexible wearable patch also includes a second flexible printed circuit board layer; the flexible stretchable electrode is electrically connected to the second flexible printed circuit board layer.

[0015] As a preferred embodiment, the flexible acoustic stack layer includes a plurality of acoustic stack units; the flexible acoustic stack layer includes a piezoelectric material layer, a first matching layer and a second matching layer stacked in sequence; wherein the second matching layer faces the flexible stretchable electrode.

[0016] As a preferred embodiment, a signal electrode and a ground electrode are provided on the piezoelectric material layer, and the signal electrode and the ground electrode are respectively arranged on the upper / lower surface or the lower / upper surface of the piezoelectric material layer; the signal electrode and the ground electrode are respectively electrically connected to the corresponding electrodes on the first flexible printed circuit board layer.

[0017] As a preferred embodiment, the signal electrode and the ground electrode are Cr / Au electrodes; the Cr / Au electrode includes a Cr layer connected to the piezoelectric material layer and an Au layer arranged on the Cr layer; in the technical solution of the present invention, the Cr layer is used to improve the adhesion of the Au layer; the Au layer provides conductivity.

[0018] And / or, the first matching layer is epoxy resin doped with aluminum oxide; the second matching layer is epoxy resin; the epoxy resin of the first matching layer and the epoxy resin of the second matching layer are of the same type.

[0019] And / or, the flexible backing layer is polydimethylsiloxane (PDMS) doped with aluminum oxide and hollow glass microspheres.

[0020] As a preferred embodiment, the method for preparing the flexible ultrasonic transducer comprises the following steps:

[0021] (1) Cutting the piezoelectric material into a piezoelectric unit array by a cutting method, filling the gaps of the piezoelectric unit array with epoxy resin; preparing a signal electrode or a ground electrode on the filled upper surface, and sequentially preparing a first matching layer and a second matching layer on the signal electrode or the ground electrode; cutting grooves on the filled lower surface to re-form the piezoelectric unit array, filling the grooves with polydimethylsiloxane, and preparing a ground electrode or a signal electrode on the filled surface to obtain a flexible acoustic stack layer having multiple acoustic stack units;

[0022] (2) bonding the surface of the flexible acoustic stack layer away from the second matching layer to the first flexible printed circuit board layer by curing epoxy resin; electrically connecting the signal electrode and the ground electrode to the corresponding electrodes on the first flexible printed circuit board layer;

[0023] (3) Preparing a flexible backing layer on the other side of the first flexible printed circuit board layer.

[0024] As a preferred embodiment, the flexible stretchable electrode includes a flexible stretchable substrate and a conductive layer provided on the flexible stretchable substrate.

[0025] As a preferred embodiment, the flexible stretchable substrate is selected from any one of silicone, styrene-ethylene-butadiene-styrene block copolymer (SEBS) and polydimethylsiloxane.

[0026] And / or, the conductive layer is selected from any one of gold, silver, and platinum; and the conductive layer is a patterned conductive layer.

[0027] As a preferred embodiment, the conductive layer of the flexible stretchable electrode is electrically connected to the second flexible printed circuit board layer via liquid metal.

[0028] As a preferred embodiment, the area on the first flexible printed circuit board layer where the flexible acoustic stack layer is not provided is bonded and connected to the flexible stretchable substrate of the flexible stretchable electrode by double-sided tape.

[0029] As a preferred embodiment, the flexible stretchable substrate is further subjected to plasma treatment before being adhered with double-sided tape.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The flexible wearable patch provided by this invention integrates ultrasonic imaging and electrical signal monitoring, enabling simultaneous in-situ monitoring of both. The flexible, stretchable electrode, with its high stretchability and low impedance, ensures stable EMG signal acquisition. It also serves as a stress relief layer, alleviating skin deformation stress and ensuring the sensor maintains stable monitoring capabilities during dynamic movements (such as arm flexion, bending, and head rotation), thereby maintaining the imaging stability of the ultrasonic transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention and its features, configurations, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals indicate like parts throughout the drawings. The drawings are not drawn to scale, emphasis instead being placed on illustrating the subject matter of the present invention.

[0033] Figure 1Schematic diagram of the structure of the flexible wearable patch in Example 1 of the present invention.

[0034] Figure 2 for Figure 1 A magnified view of the structure at location A of the medium-flexible wearable patch.

[0035] Figure 3 The imaging of muscle structure is performed by a commercial ultrasound probe and a flexible ultrasound probe prepared by the flexible wearable patch in Example 1 of the present invention.

[0036] Figure 4 3 is a graph of muscle compression rates caused by imaging muscle structures using a commercial ultrasound probe and a flexible ultrasound probe prepared using the flexible wearable patch in Example 1 of the present invention.

[0037] Figure 5 The flexible ultrasonic probe prepared by the flexible wearable patch in Example 1 of the present invention images the brachioradialis muscle of the forearm, the erector spinae muscle of the back, and the sternocleidomastoid muscle of the neck during deformation.

[0038] Figure 6a and Figure 6b Diagrams showing the adhesion states of flexible ultrasound probes prepared with flexible wearable patches with and without flexible stretchable electrodes on the neck skin.

[0039] Figure 7 This is a diagram showing the ultrasonic structure and electromyographic signal analysis results of dual-modal synchronous monitoring of the brachioradialis muscle of the forearm using the flexible ultrasonic probe prepared with the flexible wearable patch in Example 1 of the present invention.

[0040] Figure 8 This is a graph showing the results of simultaneous structure-function monitoring of children with hereditary muscular dystrophy (CMT) using a flexible ultrasound probe prepared using the flexible wearable patch in Example 1 of the present invention. DETAILED DESCRIPTION

[0041] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. It is obvious that the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative work shall fall within the scope of protection of the present invention.

[0042] It should be understood that when the terms “include” and / or “comprising” are used in this specification, they specify the presence of features, steps, operations, devices, components and / or their combinations.

[0043] In the description of the present invention, it should be noted that when terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", and "outside" appear, the orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0044] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections, direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0045] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments, unless otherwise specified, are all conventional methods in the art.

[0046] In view of the technical problem that electrophysiological electrodes and ultrasonic sensors are difficult to integrate in the prior art, the present invention provides a flexible wearable patch, the structure of which is as follows: Figure 1-2 As shown, it includes a flexible ultrasonic transducer and a flexible stretchable electrode adhered to the transducer;

[0047] The flexible ultrasonic transducer comprises a flexible backing layer, a first flexible printed circuit board layer, and a flexible acoustic stack layer provided on the first flexible printed circuit board layer, which are stacked in sequence; an area on the first flexible printed circuit board layer where the flexible acoustic stack layer is not provided is adhesively connected to a flexible stretchable electrode;

[0048] The flexible wearable patch also includes a second flexible printed circuit board layer; the flexible stretchable electrode is electrically connected to the second flexible printed circuit board layer.

[0049] In some specific embodiments, the thickness of the flexible ultrasonic transducer is 1.95-3.2 mm; the thickness of the flexible backing layer is 1.5-2.5 mm; the thickness of the flexible printed circuit board layer is 0.05-0.2 mm; and the thickness of the flexible acoustic stack layer is 0.4-0.5 mm.

[0050] In certain specific embodiments, the first flexible printed circuit board layer and / or the second flexible printed circuit board layer is a polyimide copper clad laminate.

[0051] Furthermore, the flexible acoustic stack layer includes a plurality of acoustic stack units; the flexible acoustic stack layer includes a piezoelectric material layer, a first matching layer and a second matching layer stacked in sequence; wherein the second matching layer faces the flexible stretchable electrode.

[0052] In some specific embodiments, the thickness of the piezoelectric material layer is 0.2-0.3 mm; the thickness of the first matching layer is 0.1-0.2 mm; and the thickness of the second matching layer is 0.1-0.2 mm.

[0053] In some specific embodiments, the piezoelectric material layer is a 2-2 type piezoelectric composite material, which is prepared from a piezoelectric material and a polymer; the piezoelectric material is selected from any one of lead zirconate titanate piezoelectric ceramics, barium titanate piezoelectric ceramics, lithium niobate piezoelectric ceramics, polyvinylidene fluoride and its copolymers, and lead magnesium niobate-lead titanate piezoelectric ceramics.

[0054] Furthermore, a signal electrode and a ground electrode are provided on the piezoelectric material layer, and the signal electrode and the ground electrode are respectively provided on the upper / lower surface or the lower / upper surface of the piezoelectric material layer; the signal electrode and the ground electrode are respectively electrically connected to the corresponding electrodes on the first flexible printed circuit board layer.

[0055] Furthermore, the signal electrode and the ground electrode are Cr / Au electrodes; the Cr / Au electrode includes a Cr layer connected to the piezoelectric material layer and an Au layer arranged on the Cr layer; in the technical solution of the present invention, the Cr layer is used to improve the adhesion of the Au layer; the Au layer provides conductivity.

[0056] And / or, the first matching layer is epoxy resin doped with aluminum oxide; the second matching layer is epoxy resin; the epoxy resin of the first matching layer and the epoxy resin of the second matching layer are of the same type.

[0057] Furthermore, in the first matching layer, the mass fraction of aluminum oxide is 30% to 70%; and the particle size of the aluminum oxide is 10 to 50 microns.

[0058] And / or, the flexible backing layer is polydimethylsiloxane (PDMS) doped with aluminum oxide and hollow glass microspheres.

[0059] Furthermore, in the flexible backing layer, the mass fraction of the aluminum oxide is 10% to 40%; the particle size of the aluminum oxide is 0.5 to 1 micron; the mass fraction of the hollow glass microspheres is 10% to 40%; and the particle size of the hollow glass microspheres is 1 to 5 microns.

[0060] Furthermore, the preparation method of the flexible ultrasonic transducer comprises the following steps:

[0061] (1) Cutting the piezoelectric material into a piezoelectric unit array by a cutting method, filling the gaps of the piezoelectric unit array with epoxy resin; preparing a signal electrode or a ground electrode on the filled upper surface, and sequentially preparing a first matching layer and a second matching layer on the signal electrode or the ground electrode; cutting grooves on the filled lower surface to re-form the piezoelectric unit array, filling the grooves with polydimethylsiloxane, and preparing a ground electrode or a signal electrode on the filled surface to obtain a flexible acoustic stack layer having multiple acoustic stack units;

[0062] (2) bonding the surface of the flexible acoustic stack layer away from the second matching layer to the first flexible printed circuit board layer by curing epoxy resin; electrically connecting the signal electrode and the ground electrode to the corresponding electrodes on the first flexible printed circuit board layer;

[0063] (3) Preparing a flexible backing layer on the other side of the first flexible printed circuit board layer.

[0064] In some specific embodiments, in step (1), the size of the piezoelectric unit array formed by the second cutting corresponds to the size of the piezoelectric unit array formed by the first cutting.

[0065] In certain specific embodiments, in step (1), the viscosity of the epoxy resin is 50-500 mPa·s; if the viscosity is too high, the epoxy resin has poor fluidity and is difficult to penetrate smoothly into the cutting grooves of the piezoelectric unit array, resulting in insufficient filling and affecting the packaging effect and performance.

[0066] In certain specific embodiments, in step (1), the epoxy resin used to fill the gaps in the piezoelectric unit array is of the same type as the epoxy resin used to prepare the first matching layer or the second matching layer.

[0067] In some specific embodiments, a polishing operation is further performed after filling with polydimethylsiloxane and / or filling with the first epoxy resin.

[0068] Furthermore, the flexible stretchable electrode includes a flexible stretchable substrate and a conductive layer arranged on the flexible stretchable substrate.

[0069] In certain specific embodiments, the thickness of the flexible stretchable substrate is 0.5-2 mm; and the thickness of the conductive layer is 0.3-0.5 micrometers.

[0070] Furthermore, the flexible stretchable substrate is selected from any one of silicone, styrene-ethylene-butadiene-styrene block copolymer (SEBS) and polydimethylsiloxane.

[0071] And / or, the conductive layer is selected from any one of gold, silver, and platinum; and the conductive layer is a patterned conductive layer.

[0072] Furthermore, the conductive layer of the flexible stretchable electrode is electrically connected to the second flexible printed circuit board layer through liquid metal.

[0073] Furthermore, the area on the first flexible printed circuit board layer where the flexible acoustic stack layer is not provided is bonded and connected to the flexible stretchable substrate of the flexible stretchable electrode by double-sided tape.

[0074] Furthermore, the flexible stretchable substrate is also subjected to plasma treatment before being adhered with double-sided tape.

[0075] In the technical solution of the present invention, the flexible acoustic stacking layer of the flexible ultrasonic transducer is bonded to the flexible stretchable substrate, and the integration of the ultrasonic transducer and the flexible stretchable electrode is achieved by bonding the area on the first flexible printed circuit board layer where the flexible acoustic stacking layer is not provided to the flexible stretchable substrate.

[0076] Example 1

[0077] This embodiment provides a flexible wearable patch, the preparation process of which is as follows:

[0078] 1. Preparation of Ultrasonic Transducer

[0079] (1) A 0.3 mm thick lead zirconate titanate piezoelectric ceramic sheet was mechanically cut into multiple piezoelectric ceramic units using high-precision cutting equipment to form a piezoelectric unit array; the cutting was carried out in a direction perpendicular to the thickness of the lead zirconate titanate piezoelectric ceramic sheet, and the gap formed by each cutting was 100 μm; the gaps in the formed piezoelectric unit array were filled with epoxy resin (Epo-Tek 301); after polishing to 250 μm, the first Cr / Au electrode was sputtered on the upper surface (first sputtering the Cr layer, then sputtering the Au layer); on the first Cr / Au electrode, epoxy resin (Epo-Tek 301) doped with aluminum oxide (particle size of 0.5 μm, mass fraction of 30%) was stacked as the first matching layer and pure epoxy resin (Epo-Tek 301) was stacked as the second matching layer;

[0080] (2) Cut grooves on the filled lower surface to re-form a piezoelectric unit array, and fill the grooves with PDMS (Sylgard184). The piezoelectric unit array corresponds to the gap of the piezoelectric unit array formed by cutting in step (1); after re-polishing to 250 μm, a second Cr / Au electrode is sputtered (the Cr layer is sputtered first, and then the Au layer is sputtered); the first Cr / Au electrode and the second Cr / Au electrode are used as a signal electrode and a ground electrode respectively, and the signal electrode and the ground electrode are separated by isolation cutting to obtain a flexible acoustic stack layer having multiple acoustic stack units; in this embodiment, the piezoelectric material layer obtained by the above cutting method is a 2-2 type piezoelectric composite material;

[0081] (3) The second Cr / Au electrode and the first Cr / Au electrode were electrically connected to the corresponding electrodes on the first flexible printed circuit board layer (made of polyimide copper clad laminate); epoxy resin (Epo-Tek 301) was coated on the second Cr / Au electrode and bonded to the first flexible printed circuit board layer. After curing at room temperature for 24 hours, the curing was continued at 45°C for 12 hours to form a strong and reliable bond;

[0082] (4) PDMS (flexible backing layer, thickness 2.07 mm) doped with alumina powder (particle size 0.5 μm, mass fraction 30%) and hollow glass microspheres (particle size 1 μm, mass fraction 30%) was cast on the other side of the first flexible printed circuit board layer, finally forming a flexible ultrasonic transducer with a total thickness of 430 μm.

[0083] The flexible ultrasonic transducer prepared in this embodiment has good flexibility, durability and stability.

[0084] 2. Preparation of flexible and stretchable electrodes

[0085] In this example, a 2 mm thick silicone film (Ecoflex 00-20, with an A:B mixture ratio of 1:1) was used as a flexible and stretchable substrate. The silicone liquid was spin-coated three times (200 rpm, 1 min) and cured at room temperature for 1 hour to form a film. A 400 nm thick patterned gold layer was evaporated on the silicone film to form electrode channels.

[0086] Liquid metal (a gallium-indium alloy with gallium and indium contents of 75% and 25% respectively, and a melting point of 16°C) was applied to the tail of the electrode channel using a mask roller. The pins of a second flexible printed circuit board layer (not shown) were connected to the liquid metal at the tail of the electrode channel and fixed with an adhesive (DOWSIL 734). Finally, a silicone film (Ecoflex 00-20) was used for spin coating and packaging at 1500 rpm for 1 min.

[0087] 3. Preparation of flexible wearable patches

[0088] Integrate a flexible stretchable electrode and a flexible ultrasonic transducer: Plasma-treat the side of the flexible stretchable electrode without the patterned gold layer to enhance surface energy, improve bonding strength and stability;

[0089] Double-sided tape is pasted on the area of ​​the first flexible printed circuit board layer where there is no flexible acoustic stack layer, and then the plasma-treated side of the flexible stretchable electrode is bonded to the double-sided tape to complete the integration of the flexible ultrasonic transducer and the flexible stretchable electrode to prepare a flexible wearable patch.

[0090] In order to ensure that the patch provided in this embodiment is firmly attached to the skin, its surface is treated with an adhesive. The specific steps are as follows: the surface of the flexible stretchable electrode in the flexible wearable patch is plasma treated, and the pressure-sensitive adhesive is spin-coated and cured at 60°C for 2 hours.

[0091] Figure 3 The following is a picture of a traditional commercial ultrasound probe (Siemens Acuson L10-5 Ultrasound Transducer, with a center frequency of 7.5 MHz) and a flexible ultrasound probe prepared using the flexible wearable patch in this embodiment for muscle structure imaging. It can be seen from the figure that: (1) The commercial ultrasound probe cannot truly reflect the muscle structure: the commercial probe requires pressure to be applied and an ultrasonic coupling agent is used to eliminate air gaps. When no pressure is applied, the muscle structure of the ultrasound image is blurred and difficult to identify. Only after pressure is applied can clear muscle imaging be obtained, but at the same time, the skin and superficial muscles undergo significant mechanical deformation, resulting in a reduction of tissue thickness by approximately 21.1%. This phenomenon may affect the consistency between the imaging results and the actual muscle structure, thereby reducing the accuracy of the diagnosis. (2) The flexible wearable patch in this embodiment can be used for muscle structure imaging without the need for applying pressure. It has a good conformal adhesion to the skin and can capture muscle thickness that is significantly greater than that of commercial probes.

[0092] Figure 4 Figure 3 is a graph showing muscle compression rates caused by using a traditional commercial ultrasound probe and a flexible ultrasound probe prepared using the flexible wearable patch in this embodiment for muscle structure imaging. The commercial ultrasound probe causes 21.1% tissue deformation during compression imaging, while the flexible ultrasound probe only causes 1.4% tissue deformation when directly attached for imaging.

[0093] Figure 5 The flexible ultrasound probe prepared by the flexible wearable patch in this embodiment performs ultrasound imaging of the brachioradialis muscle of the forearm, the erector spinae muscle of the back, and the sternocleidomastoid muscle of the neck under deformations of 7.2%, 26.8%, and 37.5%.

[0094] Figure 6a and Figure 6b The following are photos of the adhesion of a flexible ultrasound probe fabricated with a flexible wearable patch with and without a flexible stretchable electrode to the neck skin after multiple right rotations, used to evaluate its imaging performance under static and dynamic conditions. The test process is as follows:

[0095] A flexible ultrasound probe made of a flexible wearable patch without flexible stretchable electrodes was attached to the skin surface of the subject's neck, and an ultrasonic coupling agent was used to eliminate air gaps. In a static state, the ultrasound probe was able to achieve clear muscle imaging, and no tissue deformation due to probe pressure was observed, verifying that it can perform high-quality imaging without external pressure and has good adhesion and comfort. However, in the dynamic test, when the subject rotated his neck, as the strain on the skin surface increased, the ultrasound probe gradually detached from the skin. When the rotation reached the sixth time, the ultrasound probe was completely detached from the skin, resulting in failure of ultrasound imaging. This shows that in dynamic conditions where the skin undergoes large deformation, a simple flexible ultrasonic transducer is difficult to maintain close contact with the skin and cannot achieve continuous and stable imaging ( Figure 6a ).

[0096] In this embodiment, the flexible ultrasound probe prepared by the flexible wearable patch of the flexible stretchable electrode is attached to the surface of the skin of the human neck, and an ultrasonic coupling agent is used to eliminate the air gap. In the static state, the ultrasound probe achieved high-quality muscle imaging, and no deformation of the tissue due to the pressure of the probe was observed, showing good adhesion and comfort. In the dynamic test, when the subject rotated his neck, as the strain on the skin surface increased, the ultrasound probe was still able to adhere tightly to the skin and maintain stable imaging performance. Further tests showed that even after 150 consecutive neck rotations, high-quality ultrasound imaging was still possible, without desorption from the skin or blurred imaging, proving its long-term stability under large deformation dynamic conditions. This is mainly due to the fact that the flexible stretchable electrode effectively releases stress during skin deformation, significantly improving the adhesion between the ultrasound probe and the skin, preventing the probe from detaching due to skin strain, and thus ensuring the continuity and accuracy of imaging ( Figure 6b ).

[0097] Figure 7 The flexible ultrasound probe (WSFP) prepared by the flexible wearable patch in this embodiment performs dual-modal simultaneous monitoring of the brachioradialis muscle of the forearm using ultrasound structure and electromyographic (EMG) functional signal analysis: Figure 7 Figure a shows a photograph of the WSFP attached to the brachioradialis muscle of the forearm for structure-function monitoring; Figure 7 Figure b shows the ultrasound imaging (i) and EMG distribution (ii) of the brachioradialis muscle when relaxed and clenched. Figure 7 Figure c shows the relative relationship between muscle structural characteristics (area, minimum and maximum thickness) and EMG (RMS) during simultaneous monitoring; Figure 7 Figure d in Figure 3 shows the action recognition accuracy of unimodal and dual-modal synchronous monitoring signals. As can be seen from the figure, the action recognition accuracy of dual-modal data is significantly higher than that of unimodal data.

[0098] Figure 8 This example uses a flexible ultrasound probe fabricated using the flexible wearable patch described in this example to perform simultaneous structural-functional monitoring in children with hereditary neuromuscular dystrophy (CMT). This example illustrates simultaneous ultrasound imaging and electromyographic monitoring of children with CMT using the flexible ultrasound probe (from top to bottom, left rotation, right rotation, left flexion, and right flexion; the dashed area represents the detected sternocleidomastoid muscle (SCM) structure). As can be seen in the figure, ultrasound imaging of the affected side demonstrates severe muscle flexion, blurred edges, muscle fibrosis, and increased muscle thickness compared to the healthy side. EMG-based topographic mapping reveals bilateral asymmetry in motor tasks in CMT patients.

[0099] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A flexible wearable patch, characterized in that: It includes a flexible ultrasonic transducer and a flexible stretchable electrode adhered to the transducer; The flexible ultrasonic transducer comprises a flexible backing layer, a first flexible printed circuit board layer, and a flexible acoustic stack layer provided on the first flexible printed circuit board layer, which are stacked in sequence; an area on the first flexible printed circuit board layer where the flexible acoustic stack layer is not provided is adhesively connected to a flexible stretchable electrode; The flexible stretchable electrode includes a flexible stretchable substrate and a conductive layer provided on the flexible stretchable substrate; an area on the first flexible printed circuit board layer where the flexible acoustic stack layer is not provided is bonded and connected to the flexible stretchable substrate of the flexible stretchable electrode by double-sided tape; The flexible wearable patch further includes a second flexible printed circuit board layer; the flexible stretchable electrode is electrically connected to the second flexible printed circuit board layer; The flexible acoustic stack layer includes a plurality of acoustic stack units; the flexible acoustic stack layer includes a piezoelectric material layer, a first matching layer, and a second matching layer stacked in sequence; wherein the second matching layer faces the flexible stretchable electrode; The first matching layer is epoxy resin doped with aluminum oxide; the second matching layer is epoxy resin; And / or, the flexible backing layer is polydimethylsiloxane doped with aluminum oxide and hollow glass microspheres.

2. The flexible wearable patch according to claim 1, characterized in that A signal electrode and a ground electrode are provided on the piezoelectric material layer, and the signal electrode and the ground electrode are respectively provided on the upper / lower surface or the lower / upper surface of the piezoelectric material layer; the signal electrode and the ground electrode are respectively electrically connected to the corresponding electrodes on the first flexible printed circuit board layer.

3. The flexible wearable patch according to claim 2, characterized in that The signal electrode and the ground electrode are Cr / Au electrodes; the Cr / Au electrodes include a Cr layer connected to the piezoelectric material layer and an Au layer provided on the Cr layer; And / or, the epoxy resin of the first matching layer is of the same type as the epoxy resin of the second matching layer.

4. The flexible wearable patch according to claim 2 or 3, characterized in that: The preparation method of the flexible ultrasonic transducer comprises the following steps: (1) Cutting the piezoelectric material into a piezoelectric unit array by a cutting method, filling the gaps of the piezoelectric unit array with epoxy resin; preparing a signal electrode or a ground electrode on the filled upper surface, and sequentially preparing a first matching layer and a second matching layer on the signal electrode or the ground electrode; cutting grooves on the filled lower surface to re-form the piezoelectric unit array, filling the grooves with polydimethylsiloxane, and preparing a ground electrode or a signal electrode on the filled lower surface to obtain a flexible acoustic stack layer having a plurality of acoustic stack units; (2) bonding the surface of the flexible acoustic stack layer away from the second matching layer to the first flexible printed circuit board layer by curing epoxy resin; electrically connecting the signal electrode and the ground electrode to the corresponding electrodes on the first flexible printed circuit board layer; (3) Preparing a flexible backing layer on the other side of the first flexible printed circuit board layer.

5. The flexible wearable patch according to claim 1, characterized in that The flexible stretchable substrate is selected from any one of silicone, styrene-ethylene-butadiene-styrene block copolymer and polydimethylsiloxane; And / or, the conductive layer is selected from any one of gold, silver, and platinum; and the conductive layer is a patterned conductive layer.

6. The flexible wearable patch according to claim 1, characterized in that The conductive layer of the flexible stretchable electrode is electrically connected to the second flexible printed circuit board layer through liquid metal.

7. The flexible wearable patch according to claim 1, characterized in that The flexible and stretchable substrate is also subjected to plasma treatment before being adhered with the double-sided tape.

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