Wearable medical device, washable flexible fabric circuit board, and methods of making the same

Abstract

The application relates to the technical field of medical equipment, and discloses a wearable medical device, a washable flexible fabric circuit board and a preparation method thereof. The washable flexible fabric circuit board comprises a main body layer, a hydrophobic coating layer and a plurality of electrodes. The main body layer comprises a fabric base and a metal circuit. The fabric base has a first surface and a second surface. A flexible base material is embedded in the fabric aperture of the second surface. The metal circuit is formed on the second surface. The hydrophobic coating layer covers the main body layer. The plurality of electrodes are arranged on the fabric base and electrically connected with the metal circuit. The washable flexible fabric circuit board can make the metal circuit more simply formed on the fabric base, reduces the production difficulty, is beneficial to batch production, and the setting of the hydrophobic coating layer can also avoid the erosion of sweat and other body fluids on the metal circuit, and further improves the stability and service life of the washable flexible fabric circuit board.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a wearable medical device, a washable flexible fabric circuit board, and a method for preparing the same. Background Technology

[0002] With the rapid development of biomedical engineering and sports science, the detection, analysis and application of electromyography (EMG) signals have gradually shifted from basic research to clinical application, and are widely used in clinical medicine, rehabilitation therapy, human-computer interaction, sports science and other fields.

[0003] Traditional array electrodes are mounted on rigid circuit boards, which have poor biocompatibility, severely limiting their performance and making it difficult to meet the needs of accurate detection and analysis in practical applications. In contrast, washable flexible printed circuit boards (FPCs), also known as flexible boards or washable flexible printed circuit boards, are printed circuit boards made of flexible insulating substrates (mainly polyimide or polyester film). They have better biocompatibility and can be attached to human skin.

[0004] However, traditional washable flexible fabric circuit boards are printed circuit boards made of flexible insulating substrates (mainly polyimide or polyester film). Significant bending can still seriously affect their service life and the user experience. Summary of the Invention

[0005] This application discloses a washable flexible fabric circuit board. The fabric substrate serves as the basic carrier of the washable flexible fabric circuit board. The fabric itself has good softness and breathability, and can bend with the deformation of human skin, resulting in better fit. At the same time, by embedding a flexible substrate in the pores of the fabric on the second surface, it can support and protect the metal lines formed on the second surface, preventing the metal lines from breaking under direct stress during large bending, effectively extending the service life of the washable flexible fabric circuit board. It also makes it easier to form the metal lines on the fabric substrate, reducing the difficulty of production and preparation. The hydrophobic coating can also prevent sweat and other bodily fluids from corroding the metal lines, further improving the stability and service life of the washable flexible fabric circuit board.

[0006] To achieve the above objectives, this application discloses a washable flexible fabric circuit board, comprising: a main body layer, the main body layer including a fabric substrate and metal circuits, the fabric substrate having a first surface and a second surface, the flexible substrate being embedded in the fabric pores of the second surface, and the metal circuits being formed on the second surface; A hydrophobic coating is applied to the main body layer; Multiple electrodes are disposed on the fabric substrate and electrically connected to the metal circuit.

[0007] Thus, the washable flexible fabric circuit board can include a main body layer, within which conductive circuitry is integrated. The main body layer can include a fabric substrate and metal circuitry. The fabric substrate, being made of fabric material, possesses excellent flexibility and deformability, allowing it to bend and stretch synchronously with muscle deformation, unlike rigid circuit boards which limit the overall deformation capability of the sensor. Simultaneously, a flexible substrate is embedded within the fabric pores on the second surface of the fabric substrate. This flexible substrate fills the pores, providing a stable support for the metal circuitry and ensuring its stability without significantly sacrificing overall flexibility. Furthermore, the combination of the fabric and the flexible substrate ensures the overall structural strength, preventing breakage or detachment of the metal circuitry after long-term deformation, thus improving the stability of the washable flexible fabric circuit board and extending its service life. A hydrophobic coating covering the main body layer isolates sweat and other bodily fluids from the skin surface, preventing sweat from seeping into the metal circuitry and causing corrosion or short circuits. This further ensures the conductivity stability of the metal circuitry and extends the service life of the washable flexible fabric circuit board. The hydrophobic coating also possesses a degree of flexibility, not affecting the overall structural conformability and deformation capability. Moreover, compared to wrapping a waterproof membrane around the outer surface of the main body layer, the hydrophobic coating in this embodiment can be directly coated and formed on the surface of the processed main body layer without increasing the overall thickness. This makes it easier to adhere to the skin, does not affect the detection accuracy of electromyography signals, and avoids increasing the overall rigidity of the washable flexible fabric circuit board, ensuring a comfortable user experience. In addition, since the metal lines will protrude from the second surface after being formed, the protruding line height c can be 5μm≤c≤10μm. This may cause tiny gaps when the waterproof membrane is wrapped. However, the hydrophobic coating can be uniformly adhered and formed around the metal lines and on the surface, resulting in a better sealing effect and better isolation of sweat and other bodily fluids, thus improving the protective effect.

[0008] As an optional implementation, the fabric substrate includes: an interaction portion, a connecting portion, and an electrode mounting portion. The two ends of the connecting portion are respectively connected to the interaction portion and the electrode mounting portion. The interaction portion is provided with a plurality of interaction points for electrically connecting to the controller. Each electrode is disposed in the electrode mounting portion. The two ends of each metal line are electrically connected to one interaction point and one electrode.

[0009] In this way, the interaction unit can be electrically connected to an external controller, transmitting the electromyographic signals collected by each electrode to the controller through corresponding metal lines. The connection unit is used to connect the interaction unit and the electrode mounting unit into a whole. The size of the connection unit can be adjusted according to the shape of the target application site, so that the washable flexible fabric circuit board can be adapted to the wearing needs of different parts. The electrodes are uniformly set in the electrode mounting unit, which allows each electrode to be arranged in a pre-designed position, ensuring the precision of the electrode's fit to the skin, thereby ensuring the accuracy of the collected electromyographic signals. Each metal line is connected to an interaction point and an electrode respectively, which can realize independent signal transmission, avoid mutual interference between signals from different channels, and further improve the accuracy of signal acquisition.

[0010] As an optional implementation, the spacing 'a' between two adjacent electrodes satisfies: 4mm ≤ a ≤ 10mm.

[0011] In this way, by controlling the spacing between adjacent electrodes within the range of 4mm to 10mm, it is possible to avoid excessive overlap of muscle signals acquired by adjacent electrodes due to excessively small spacing (a < 4mm) and failure to acquire electromyographic signals in some areas due to excessively large spacing (a > 10mm). This approach can balance the density and independence of signal acquisition, accommodate a sufficient number of acquisition channels within a limited area, and ensure the accuracy of each channel signal, thus meeting the precision requirements of electromyographic signal acquisition.

[0012] As an optional implementation, the metal circuit includes: an interaction point connection segment, a main body segment, and an electrode connection segment. The two ends of the main body segment are electrically connected to the interaction point connection segment and the electrode connection segment, respectively. The angle between the interaction point connection segment and the main body segment is an obtuse angle, and the angle between the electrode connection segment and the main body segment is also an obtuse angle.

[0013] Thus, the angle between the interaction point connecting segment and the main body segment, and the angle between the electrode connecting segment and the main body segment, can be acute, right, or obtuse. In this embodiment, an obtuse angle is used to avoid stress concentration at the angle. When the washable flexible fabric circuit board undergoes bending deformation, the stress at the obtuse angle can be better dispersed, preventing the metal circuit from breaking at the angle due to repeated bending. This further improves the overall deformation resistance of the metal circuit structure and extends its service life. Moreover, the current in the metal circuit can flow more smoothly through the corner, reducing impedance at the corner, improving signal transmission stability, avoiding excessive signal attenuation during transmission, and ensuring that the signal strength received by the back-end controller meets the detection requirements.

[0014] As an optional implementation, a portion of the electrodes are spaced apart along a first direction, and a portion of the electrodes are spaced apart along a second direction, the second direction being perpendicular to the first direction, and the main body segment extends along the first direction; Among them, multiple groups of main body segments are arranged at intervals along the second direction, and each group of main body segments contains multiple segments. Along the second direction, each group of main body segments and the electrode are arranged at intervals in sequence.

[0015] In this way, by arranging the electrodes at intervals along the first and second directions, and simultaneously arranging the corresponding main body segments at intervals along the second direction in groups, more electrodes and metal lines can be reasonably arranged within a limited area. This not only expands the acquisition coverage of electromyographic signals but also avoids cross-short circuits between different metal lines, ensuring the independence of signal transmission in each channel and improving the reliability of signal acquisition. The arrangement of the main body segments and electrodes at intervals along the second direction makes the wiring of the entire washable flexible fabric circuit board more regular and easier to align during production, further improving the production yield.

[0016] As an optional implementation, the multiple sets of main body segments include two first sets of main body segments and multiple second sets of main body segments. Along the second direction, the first sets of main body segments are located at the edge of the electrode mounting portion, and each set of second sets of main body segments is located between two first sets of main body segments. Each set of second sets of main body segments is electrically connected to the electrodes on its adjacent two sides.

[0017] In this way, the first set of main body segments is arranged on both sides of the electrode mounting part, and only needs to be electrically connected to the adjacent electrode on the same side. The second set of main body segments is arranged between the two first sets of main body segments, and each second set of main body segments is electrically connected to the electrodes on its adjacent two sides. This arrangement design can make full use of the space between the first sets of main body segments, without reserving space for a separate set of main body segments for each electrode. While ensuring that different lines do not cross, it further reduces the area required for the overall wiring, making the overall structure of the washable flexible fabric circuit board more compact and suitable for small-sized wearing needs.

[0018] As an optional implementation, the metal circuit is made of silver or a silver alloy.

[0019] Thus, silver and silver alloys possess excellent electrical conductivity and low resistivity, resulting in less signal attenuation during transmission and ensuring more stable transmission of collected electromyographic signals. Simultaneously, silver and silver alloys exhibit good ductility, allowing them to undergo stretching and bending deformations along with the fabric substrate. They are less prone to embrittlement and fracture during repeated deformation, further extending the lifespan of the metal circuitry and meeting the requirements for long-term deformation use of washable flexible fabric circuit boards.

[0020] As an optional implementation, the line width b of the metal circuit satisfies: 0.1mm ≤ b ≤ 0.35mm.

[0021] Thus, controlling the line width of the metal circuit within the range of 0.1mm to 0.35mm can avoid the following problems: excessively small line width (b < 0.1mm) leads to more complex manufacturing processes, lower yield, and higher impedance of the circuit itself, resulting in more significant signal attenuation during transmission. At the same time, it can also avoid excessively large line width (b > 0.35mm) which occupies too much wiring space, resulting in a loose overall wiring structure and a larger overall size of the washable flexible fabric circuit board. This ensures that the metal circuit has appropriate resistance to guarantee signal transmission stability, while also accommodating more circuits within a limited area, adapting to the compact wiring requirements of multiple acquisition channels.

[0022] As an optional implementation, the line height c of the metal circuit satisfies: 5μm≤c≤10μm.

[0023] Thus, by controlling the line height of the metal circuit within the range of 5μm to 10μm, we can avoid the problem of excessively small line height (c < 5μm) leading to high resistance of the circuit itself and making it prone to wire breakage defects during the molding process, thus reducing the production yield. At the same time, we can avoid excessively large line height (c > 10μm) leading to excessive overall stiffness of the circuit, which would affect the overall deformation capability of the washable flexible fabric circuit board and increase the amount of raw materials used, thus increasing the production cost. This approach ensures that the metal circuit has sufficient structural strength and suitable conductivity without sacrificing the overall softness and deformability of the washable flexible fabric circuit board, thus balancing production difficulty, production cost, and performance.

[0024] As an optional implementation, the resistance value R of each of the metal lines satisfies: 19Ω≤R≤35Ω.

[0025] Thus, by controlling the resistance value of each metal line within the range of 19Ω to 35Ω, it is possible to avoid excessive attenuation during signal transmission due to excessively high resistance (R>35Ω), resulting in insufficient EMG signal strength received by the back-end controller and affecting the accuracy of signal analysis and processing. At the same time, it is also possible to avoid excessively low resistance (R<19Ω), which would require increasing the line width or line height, occupying too much wiring space and increasing production costs. This resistance range can ensure the stability of EMG signal transmission, meet the accuracy requirements of back-end signal detection and processing, and also adapt to compact wiring designs and control production costs.

[0026] This application also discloses a wearable medical device, including the aforementioned washable flexible fabric circuit board.

[0027] Thus, applying washable flexible fabric circuit boards to wearable medical devices leverages the excellent softness, conformability, conductivity, and washability of the fabric circuit boards. This allows wearable medical devices to be worn on the skin for extended periods, comfortably collecting and detecting physiological signals such as electromyography (EMG) signals. This meets the needs of long-term dynamic monitoring, preventing discomfort from reducing user willingness to use the device. At the same time, it ensures sufficient accuracy of the collected physiological signals, providing a reliable basis for clinical diagnosis and rehabilitation monitoring. Moreover, washable flexible fabric circuit boards can be directly integrated into corresponding clothing. For example, the inner fabric of a knee brace can be used as the fabric base, and electrodes can be used to stimulate the area around the knee covered by the knee brace or collect electromyographic signals. Similarly, the inner fabric of a vest can be used as the fabric base, and electrodes can be used to stimulate a specific part of the human torso (shoulders, neck, waist, abdomen, etc.) or collect electromyographic signals. For example, the inner fabric of a wristband can be used as the fabric base, and electrodes can be used to stimulate the wrist area or collect electromyographic signals. Furthermore, the inner fabric of a sock can be used as the fabric base, and electrodes can be used to stimulate the feet and calves. Wearing and using this technology is more natural and convenient, without adding extra burden to the user, and is suitable for everyday use scenarios.

[0028] This application also discloses a method for preparing a washable flexible fabric circuit board, comprising: printing metal lines on a flexible substrate; embedding the flexible substrate into the fabric gaps of a fabric substrate through a hot pressing process, so that the metal lines are transferred to the fabric substrate; installing multiple electrodes on the fabric substrate, so that each electrode is electrically connected to the corresponding metal line; shielding each electrode and immersing the fabric substrate in a hydrophobic coating, so that the outer periphery of the fabric substrate and the metal lines are covered with a hydrophobic coating.

[0029] In this way, a pre-designed metal circuit pattern is first formed on a flexible substrate using a printing process, resulting in high processing precision, good pattern consistency, and suitability for mass production. Then, a hot-pressing process is used to embed the flexible substrate into the gaps of the fabric substrate, simultaneously transferring the metal circuit pattern. The processing steps are simple, requiring no complex pretreatment of the fabric itself, and it can adapt to different specifications and types of fabric substrates, offering good processing compatibility. After the transfer is completed, electrodes are directly installed to ensure reliable electrical connection between the electrodes and the metal circuit. Finally, a hydrophobic coating is applied to the entire substrate by immersion, which also pre-masks the electrodes. This allows both the fabric substrate and the metal circuit to be covered with a hydrophobic coating, achieving water resistance and corrosion resistance, without affecting the conductivity of the electrodes in contact with the skin. This avoids the increase in electrode impedance caused by the hydrophobic coating covering the electrodes, which could affect signal acquisition. The entire preparation method is simple, has low processing difficulty, and can stably produce washable flexible fabric circuit boards with reliable structure and excellent performance, making it suitable for large-scale mass production.

[0030] Compared with the prior art, the beneficial effects of this application are: The washable flexible fabric circuit board provided in this application uses a fabric substrate as its support. Utilizing the fabric's inherent softness and breathability, the circuit board can better conform to the deformation of human skin, improving its fit and adapting to the contours of different parts of the body, thus meeting the fitting requirements for electromyography (EMG) signal acquisition. By embedding a flexible substrate within the pores of the fabric substrate's second surface, the overall softness of the substrate is ensured, while a stable forming and support foundation is provided for the metal circuitry. This facilitates the layout of the metal circuitry, reduces manufacturing difficulty, and disperses the stress on the metal circuitry during deformation, preventing breakage due to direct force during significant bending, effectively extending the service life of the washable flexible fabric circuit board. The hydrophobic coating isolates sweat and other bodily fluids, preventing corrosion of the metal circuitry and further improving the stability and extending the service life of the washable flexible fabric circuit board. Adapting to the needs of human EMG signal acquisition, it better meets the application requirements of multiple fields such as clinical medicine, rehabilitation therapy, human-computer interaction, and sports science. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of the washable flexible fabric circuit board disclosed in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a washable flexible fabric circuit board from another angle, as disclosed in an embodiment of this application. Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the structure of a washable flexible fabric circuit board from another angle, as disclosed in the embodiments of this application. Figure 5 for Figure 4 Enlarged view of point B in the middle.

[0033] Explanation of reference numerals in the attached figures: 100 - Main body layer; 11 - Fabric substrate; 111 - First surface; 112 - Second surface; 113 - Flexible substrate; 114 - Interaction part; 115 - Connection part; 116 - Electrode mounting part; 12 - Metal circuit; 121 - Interaction point connection segment; 122 - Main body segment; 1221 - First group of main body segments; 1222 - Second group of main body segments; 123 - Electrode connection segment; 200 - Electrode; 300 - Interaction point; y - First direction; x - Second direction. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. The described embodiments are only a part of this application, and not all of them. Other embodiments that can be obtained by those skilled in the art without creative effort based on the content of this application are all within the protection scope of this application.

[0035] The directional or positional terms used in this application, such as "upper," "lower," "inner," and "outer," are based on the directions shown in the accompanying drawings and are used only for descriptive purposes, not to limit the actual location or structure. Some terms may have other meanings in different contexts, and those skilled in the art should understand them according to the specific context.

[0036] The terms "installation," "setup," and "connection" should be interpreted broadly, including but not limited to fixed or detachable, mechanical or electrical, direct or indirect connection methods. The terms "first," "second," etc., are used only to distinguish objects and do not indicate importance or order.

[0037] Washable flexible printed circuit boards (FPCs), also known as flexible boards or washable flexible printed circuit boards, are printed circuit boards made of flexible insulating substrates (mainly polyimide or polyester film). They offer better biocompatibility and can adhere to human skin. However, traditional washable flexible printed circuit boards, made of flexible insulating substrates (mainly polyimide or polyester film), are still susceptible to significant lifespan reduction and user experience issues from excessive bending.

[0038] Based on this, this application discloses a washable flexible fabric circuit board. The fabric substrate serves as the basic carrier of the washable flexible fabric circuit board. The fabric itself has good softness and breathability, and can bend with the deformation of human skin, resulting in better fit. At the same time, by embedding a flexible substrate in the pores of the fabric on the second surface, the metal circuit formed on the second surface can be supported and protected, preventing the metal circuit from being directly broken by force during large bending, effectively extending the service life of the washable flexible fabric circuit board. It also makes it easier to form the metal circuit on the fabric substrate, reducing the difficulty of production and preparation. The hydrophobic coating can also prevent sweat and other bodily fluids from corroding the metal circuit, further improving the stability and service life of the washable flexible fabric circuit board.

[0039] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0040] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a washable flexible fabric circuit board disclosed in an embodiment of this application. This application discloses a washable flexible fabric circuit board, comprising: a main body layer 100, a hydrophobic coating, and multiple electrodes 200. The main body layer 100 includes a fabric substrate 11 and metal lines 12. The fabric substrate 11 has a first surface 111 and a second surface 112. A flexible substrate 113 (not shown in the figure) is embedded in the fabric pores of the second surface 112. The metal lines 12 are formed on the second surface 112. The hydrophobic coating covers the main body layer 100. Multiple electrodes 200 are disposed on the fabric substrate 11 and electrically connected to the metal lines 12.

[0041] In some embodiments, the washable flexible fabric circuit board may include a main body layer 100, which integrates conductive lines. The main body layer 100 may include a fabric substrate 11 and metal lines 12. The fabric substrate 11 is made of fabric material, which has good softness and deformability. It can bend and stretch synchronously with the deformation of muscles, unlike rigid circuit boards which limit the overall deformation capability of the sensor. At the same time, a flexible substrate 113 is embedded in the fabric pores of the second surface 112 of the fabric substrate 11. The flexible substrate 113 can fill the pores to provide a stable support for the metal lines 12, ensuring the stability of the metal lines 12 layout, without significantly sacrificing the overall softness. Moreover, the combination of the fabric and the flexible substrate 113 can also ensure the strength of the overall structure, avoiding the problem of metal lines 12 breaking or falling off after long-term deformation, improving the stability of the washable flexible fabric circuit board and extending its service life.

[0042] Combination Figure 1In some embodiments, the metal lines 12 are directly formed on the second surface 112 where the flexible substrate 113 is embedded, and can be directly used as conductive lines, eliminating the need for an additional rigid circuit board structure and further ensuring the overall flexibility of the sensor. The metal lines 12 are directly formed on the second surface 112 where the flexible substrate 113 is embedded, replacing the rigid wiring structure of the traditional rigid circuit board, and further improving the flexibility of the overall structure.

[0043] In some embodiments, the flexible substrate 113 may be a silicone substrate or a plastic film substrate. Specifically, the silicone substrate may be TPU (Thermoplastic Polyurethane).

[0044] In some embodiments, the metal circuit 12 can be made of silver paste. The circuit after silver paste printing has low resistance and good conductivity. At the same time, it also has a certain degree of flexibility and can deform together with the fabric substrate 11. It is not easy to have embrittlement and breakage problems, and its service life is also longer.

[0045] In some embodiments, the metal circuit 12 can be transferred to the fabric substrate 11 by printing silver paste onto a flexible substrate 113 and then embedding the flexible substrate 113 with the metal circuit 12 onto the fabric substrate 11 through a hot pressing process. This preparation method is simple and efficient, eliminating the need for direct printing on the soft fabric surface, reducing processing difficulty, improving the molding accuracy and yield of the metal circuit 12, ensuring the bonding stability between the metal circuit 12 and the fabric substrate 11, and reducing production costs.

[0046] Combination Figure 1In some embodiments, a hydrophobic coating covers the main body layer 100, which can isolate body fluids such as sweat generated on the skin surface, prevent sweat from seeping into the metal circuit 12 and causing problems such as circuit corrosion and short circuits, further ensuring the conductivity stability of the metal circuit 12, and also extending the service life of the washable flexible fabric circuit board. At the same time, the hydrophobic coating also has a certain degree of flexibility and will not affect the overall structure's ability to fit and deform. Moreover, compared to wrapping a waterproof membrane around the outer surface of the main body layer 100, the hydrophobic coating in this embodiment can be directly coated and formed on the surface of the processed main body layer 100 without increasing the overall thickness. This makes it easier to adhere to the skin, does not affect the detection accuracy of electromyography signals, and avoids increasing the overall hardness of the washable flexible fabric circuit board, ensuring a comfortable user experience. In addition, since the metal line 12 protrudes from the second surface 112 after it is formed, the protruding line height c can be 5μm≤c≤10μm. This may cause tiny gaps when the waterproof membrane is wrapped. However, the hydrophobic coating can be uniformly adhered and formed around the metal line 12 and on its surface, resulting in a better sealing effect and better isolation of sweat and other bodily fluids, thus improving the protective effect.

[0047] Combination Figure 2 , Figure 2 This is a schematic diagram of the structure of a washable flexible fabric circuit board disclosed in another embodiment of this application. In some embodiments, multiple electrodes 200 are disposed on the fabric substrate 11, and each electrode 200 is electrically connected to a corresponding metal line 12. The electrodes 200 can be used to collect electromyographic signals from the skin surface, and then the collected signals are transmitted to a back-end controller for processing through the metal line 12, thereby realizing the acquisition and detection of electromyographic signals. The electrodes 200 can be flexible electrodes, which can better conform to human skin, collect electromyographic signals more accurately, ensure the reliability of signal acquisition, provide a more accurate basis for subsequent signal analysis and processing, and thus meet the needs of electromyographic detection in multiple fields such as clinical medicine and rehabilitation therapy.

[0048] According to embodiments of the present invention, the washable flexible fabric circuit board uses a fabric substrate 11 as a supporting base. Utilizing the inherent softness and breathability of the fabric, the circuit board can better conform to the deformation of human skin, improving its fit and adapting to the contours of different parts of the body, thus meeting the fitting requirements for electromyography signal acquisition. By embedding a flexible substrate 113 within the pores of the second surface 112 of the fabric substrate 11, the overall softness of the substrate is ensured, while a stable forming and support base is provided for the metal circuitry 12. This facilitates the layout of the metal circuitry 12, reduces the difficulty of manufacturing, and disperses the stress borne by the metal circuitry 12 during deformation, preventing breakage due to direct stress during large-scale bending, effectively extending the service life of the washable flexible fabric circuit board. The hydrophobic coating isolates sweat and other bodily fluids, preventing corrosion of the metal circuitry 12, further improving the stability of the washable flexible fabric circuit board and extending its service life. It is adapted to the needs of human electromyography signal acquisition and can better meet the application requirements of multiple fields such as clinical medicine, rehabilitation therapy, human-computer interaction, and sports science.

[0049] Combination Figure 2 In some embodiments, the fabric substrate 11 includes an interaction portion 114, a connecting portion 115, and an electrode mounting portion 116. The two ends of the connecting portion 115 are respectively connected to the interaction portion 114 and the electrode mounting portion 116. The interaction portion 114 is provided with a plurality of interaction points 300 for electrically connecting to the controller. Each electrode 200 is provided on the electrode mounting portion 116. The two ends of each metal line 12 are electrically connected to an interaction point 300 and an electrode 200.

[0050] Specifically, the interaction unit 114 can be electrically connected to an external controller, transmitting the electromyographic signals collected by each electrode 200 to the controller via the corresponding metal line 12. The connection unit 115 connects the interaction unit 114 and the electrode mounting unit 116 into a whole. The size of the connection unit 115 can be adjusted according to the shape of the target application area, making it easy for the washable flexible fabric circuit board to adapt to the wearing needs of different parts. The electrodes 200 are uniformly set in the electrode mounting unit 116, allowing each electrode 200 to be arranged in a pre-designed position, ensuring the adhesion accuracy between the electrodes 200 and the skin, thereby ensuring the accuracy of the collected electromyographic signals. Each metal line 12 is connected to an interaction point 300 and an electrode 200 respectively, enabling independent signal transmission and avoiding mutual interference between signals from different channels, further improving the accuracy of signal acquisition.

[0051] Combination Figure 2 In some embodiments, the spacing 'a' between two adjacent electrodes 200 satisfies: 4mm ≤ a ≤ 10mm.

[0052] Specifically, controlling the spacing between adjacent electrodes 200 within the range of 4mm to 10mm can avoid excessive overlap of muscle signals acquired by adjacent electrodes 200 due to excessively small spacing (a < 4mm), and failure to acquire electromyographic signals in some areas due to excessively large spacing (a > 10mm). This balances the density and independence of signal acquisition, accommodates a sufficient number of acquisition channels within a limited area, and ensures the accuracy of each channel signal, thus meeting the precision requirements of electromyographic signal acquisition.

[0053] Combination Figure 2 In some embodiments, the metal line 12 includes: an interaction point connection segment 121, a main body segment 122 and an electrode connection segment 123. The two ends of the main body segment 122 are electrically connected to the interaction point connection segment 121 and the electrode connection segment 123 respectively. The angle between the interaction point connection segment 121 and the main body segment 122 is an obtuse angle, and the angle between the electrode connection segment 123 and the main body segment 122 is an obtuse angle.

[0054] Specifically, the angle between the interaction point connection segment 121 and the main body segment 122, and the angle between the electrode connection segment 123 and the main body segment 122, can be acute, right, or obtuse. In this embodiment, an obtuse angle is used to avoid stress concentration at the angle. When the washable flexible fabric circuit board undergoes bending deformation, the stress at the obtuse angle can be better dispersed, preventing the metal line 12 from breaking at the angle due to repeated bending. This further improves the overall deformation resistance of the metal line 12 and extends its service life. Moreover, the current in the metal line 12 can flow more smoothly through the corner, reducing the impedance at the corner, improving the stability of signal transmission, avoiding excessive signal attenuation during transmission, and ensuring that the signal strength received by the back-end controller meets the detection requirements.

[0055] Combination Figure 2 In some embodiments, a number of electrodes 200 are arranged at intervals along a first direction y, and a number of electrodes 200 are arranged at intervals along a second direction x, the second direction x being perpendicular to the first direction y, and the main body segment 122 extending along the first direction y; wherein, multiple groups of main body segments 122 are arranged at intervals along the second direction x, and each group of main body segments 122 contains multiple segments, and along the second direction x, each group of main body segments 122 and the electrodes 200 are arranged at intervals in sequence.

[0056] Specifically, the electrodes 200 are arranged at intervals along the first direction y and the second direction x, while the corresponding main body segments 122 are arranged in groups at intervals along the second direction x. This allows for the reasonable arrangement of more electrodes 200 and metal lines 12 within a limited area, which can expand the acquisition coverage of electromyographic signals and avoid cross-short circuits between different metal lines 12, ensuring the independence of signal transmission in each channel and improving the reliability of signal acquisition. The arrangement of the main body segments 122 and electrodes 200 at intervals along the second direction x makes the wiring of the entire washable flexible fabric circuit board more regular and easier to align during production, further improving the production yield.

[0057] Combination Figure 2 In some embodiments, the multiple sets of main body segments 122 include two first sets of main body segments 1221 and multiple second sets of main body segments 1222. Along the second direction x, the first sets of main body segments 1221 are located at the edge of the electrode mounting portion 116, and each set of second sets of main body segments 1222 is located between the two first sets of main body segments 1221. Each set of second sets of main body segments 1222 is electrically connected to the electrodes 200 on its adjacent two sides.

[0058] Specifically, the first set of main body segments 1221 are arranged on both sides of the electrode mounting part 116, and only need to be electrically connected to the adjacent electrode 200 on the same side. The second set of main body segments 1222 are arranged between the two first sets of main body segments 1221. Each second set of main body segments 1222 is electrically connected to the electrode 200 on its adjacent two sides. This arrangement design can make full use of the space between the first set of main body segments 1221, without reserving a separate arrangement space for a set of main body segments 122 for each electrode 200. While ensuring that different lines do not cross, it further reduces the area required for the overall wiring, making the overall structure of the washable flexible fabric circuit board more compact and suitable for small-sized wearing needs.

[0059] In some embodiments, the metal circuit 12 is made of silver or a silver alloy.

[0060] Specifically, silver and silver alloys have excellent electrical conductivity and low resistivity, resulting in less attenuation during signal transmission and ensuring more stable transmission of collected electromyographic signals. At the same time, silver and silver alloys have good ductility, allowing them to stretch and bend along with the fabric substrate 11. They are less prone to embrittlement and breakage during repeated deformation, further improving the service life of the metal circuit 12 and meeting the requirements for long-term deformation use of washable flexible fabric circuit boards.

[0061] Combination Figure 3 , Figure 3 for Figure 2 Enlarged view of point A. In some embodiments, the line width b of the metal line 12 satisfies: 0.1mm ≤ b ≤ 0.35mm.

[0062] Specifically, controlling the line width of the metal line 12 within the range of 0.1mm to 0.35mm can avoid the following: if the line width is too small (b < 0.1mm), the manufacturing process will be more complicated, the yield will be lower, and the impedance of the line itself will be higher, resulting in more significant signal attenuation during transmission. At the same time, it can also avoid the following: if the line width is too large (b > 0.35mm), it will occupy too much wiring space, resulting in a loose overall wiring structure and a larger overall size of the washable flexible fabric circuit board. This ensures that the metal line 12 has appropriate resistance to guarantee the stability of signal transmission, while also accommodating more lines in a limited area to meet the compact wiring requirements of multiple acquisition channels.

[0063] Combination Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of the structure of a washable flexible fabric circuit board from another angle, as disclosed in an embodiment of this application. Figure 5 for Figure 4 Enlarged view at point B. In some embodiments, the line height c of the metal line 12 satisfies: 5μm≤c≤10μm.

[0064] Specifically, controlling the line height of the metal circuit 12 within the range of 5μm to 10μm can avoid the problem of excessively small line height (c < 5μm) leading to high resistance of the circuit itself and easy breakage defects during the molding process, thus reducing the production yield. At the same time, it can also avoid excessively large line height (c > 10μm) leading to excessive overall stiffness of the circuit, which would affect the overall deformation capability of the washable flexible fabric circuit board and increase the amount of raw materials used, thus increasing the production cost. This approach ensures that the metal circuit 12 has sufficient structural strength and suitable conductivity without sacrificing the overall soft and deformable characteristics of the washable flexible fabric circuit board, thus balancing production difficulty, production cost, and performance.

[0065] In some embodiments, the resistance value R of each metal line 12 satisfies: 19Ω≤R≤35Ω.

[0066] Specifically, controlling the resistance value of each metal line 12 within the range of 19Ω to 35Ω avoids excessive attenuation during signal transmission due to excessively high resistance (R>35Ω), resulting in insufficient EMG signal strength received by the back-end controller and affecting the accuracy of signal analysis and processing. At the same time, it avoids the need to increase line width or line height due to excessively low resistance (R<19Ω), which would occupy too much wiring space and increase production costs. This resistance range can ensure the stability of EMG signal transmission, meet the accuracy requirements of back-end signal detection and processing, and also adapt to compact wiring design and control production costs.

[0067] This application also discloses a wearable medical device, including the aforementioned washable flexible fabric circuit board.

[0068] Specifically, applying washable flexible fabric circuit boards to wearable medical devices leverages the excellent softness, conformability, conductivity, and washability of the fabric circuit boards. This allows wearable medical devices to be worn on the skin for extended periods, comfortably collecting and detecting physiological signals such as electromyography (EMG) signals. This meets the needs of long-term dynamic monitoring, preventing discomfort from reducing user willingness to use the device. At the same time, it ensures sufficient accuracy of the collected physiological signals, providing a reliable basis for clinical diagnosis and rehabilitation monitoring. Moreover, washable flexible fabric circuit boards can be directly integrated into corresponding clothing. For example, the inner fabric of a knee brace can be used as the fabric base 11, and electrodes 200 can be used to stimulate the area around the knee covered by the knee brace or collect electromyographic signals. For example, the inner fabric of a vest can be used as the fabric base 11, and electrodes 200 can be used to stimulate a certain part of the human torso (shoulders, neck, waist, abdomen, etc.) with current or collect electromyographic signals. For example, the inner fabric of a wristband can be used as the fabric base 11, and electrodes 200 can be used to stimulate the wrist area with current or collect electromyographic signals. For example, the inner fabric of a sock can be used as the fabric base 11, and electrodes 200 can be used to stimulate the feet and calves with current or collect electromyographic signals. Wearing and using this technology is more natural and convenient, without adding extra burden to the user, and is suitable for daily use scenarios.

[0069] This application also discloses a method for preparing a washable flexible fabric circuit board. The method includes: printing metal lines 12 on a flexible substrate; embedding the flexible substrate into the fabric gaps of a fabric base 11 by a hot pressing process, so that the metal lines 12 are transferred to the fabric base 11; installing a plurality of electrodes 200 on the fabric base 11, so that each electrode 200 is electrically connected to the corresponding metal line 12; shielding each electrode 200 and immersing the fabric base 11 in a hydrophobic coating, so that the outer periphery of the fabric base 11 and the metal lines 12 are covered with a hydrophobic coating.

[0070] Specifically, the process involves first forming a pre-designed metal circuit 12 on a flexible substrate using a printing process. This process offers high precision, good pattern consistency, and suitability for mass production. Then, a hot-pressing process embeds the flexible substrate into the gaps of the fabric substrate 11, simultaneously transferring the metal circuit 12. This simple process eliminates the need for complex pretreatment of the fabric itself, adapts to different specifications and types of fabric substrates, and offers good processing compatibility. After the transfer is complete, electrodes 200 are directly installed, ensuring reliable electrical connection between the electrodes 200 and the metal circuit 12. Finally, a hydrophobic coating is applied to the entire substrate through immersion, while also pre-masking the electrodes 200. This allows both the fabric substrate 11 and the metal circuit 12 to be covered with a hydrophobic coating for water resistance and corrosion resistance, without affecting the conductivity of the electrodes 200 in contact with the skin. This avoids the increased impedance of the electrodes 200 due to the hydrophobic coating, which could affect signal acquisition. The entire preparation method is simple, has low processing difficulty, and can stably produce a reliable, high-performance washable flexible fabric circuit board, suitable for large-scale mass production.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and do not constitute a limitation. The embodiments can be freely combined without conflict. Although each embodiment has been described in detail, those skilled in the art should understand that modifications can still be made to the technical solutions or equivalent substitutions can be made to the technical features, and all such modifications or substitutions should be covered within the scope of the technical solutions of this application.

Claims

1. A washable flexible fabric circuit board, characterized in that, include: The main body layer (100) includes a fabric substrate (11) and a metal circuit (12). The fabric substrate (11) has a first surface (111) and a second surface (112). A flexible substrate (113) is embedded in the fabric pores of the second surface (112). The metal circuit (12) is formed on the second surface (112). A hydrophobic coating is applied to the main body layer (100); Multiple electrodes (200) are disposed on the fabric substrate (11) and electrically connected to the metal circuit (12). The electrodes (200) are used to emit stimulation current or collect electromyographic signals.

2. The washable flexible fabric circuit board according to claim 1, characterized in that, The fabric substrate (11) includes an interaction part (114), a connecting part (115), and an electrode mounting part (116). The two ends of the connecting part (115) are respectively connected to the interaction part (114) and the electrode mounting part (116). The interaction part (114) is provided with a plurality of interaction points (300) for electrically connecting to the controller. Each electrode (200) is provided on the electrode mounting part (116). The two ends of each metal line (12) are electrically connected to one interaction point (300) and one electrode (200).

3. The washable flexible fabric circuit board according to claim 1, characterized in that, The spacing a between two adjacent electrodes (200) satisfies: 4mm ≤ a ≤ 10mm.

4. The washable flexible fabric circuit board according to claim 2, characterized in that, The metal circuit (12) includes: an interaction point connection segment (121), a main body segment (122), and an electrode connection segment (123). The two ends of the main body segment (122) are electrically connected to the interaction point connection segment (121) and the electrode connection segment (123) respectively. The angle between the interaction point connection segment (121) and the main body segment (122) is an obtuse angle, and the angle between the electrode connection segment (123) and the main body segment (122) is an obtuse angle.

5. The washable flexible fabric circuit board according to claim 4, characterized in that, A portion of the electrodes (200) are spaced apart along a first direction (y), and a portion of the electrodes (200) are spaced apart along a second direction (x), the second direction (x) being perpendicular to the first direction (y), and the main body segment (122) extending along the first direction (y); Among them, multiple sets of main body segments (122) are arranged at intervals along the second direction (x), and the number of main body segments (122) in each set is multiple. Along the second direction (x), each set of main body segments (122) and the electrode (200) are arranged at intervals in sequence.

6. The washable flexible fabric circuit board according to claim 5, characterized in that, The multiple sets of main body segments (122) include two first sets of main body segments (1221) and multiple second sets of main body segments (1222). Along the second direction (x), the first sets of main body segments (1221) are located at the edge of the electrode mounting portion (116), and each set of second sets of main body segments (1222) is located between two first sets of main body segments (1221). Each set of second sets of main body segments (1222) is electrically connected to the electrodes (200) on its adjacent two sides.

7. The washable flexible fabric circuit board according to claim 1, characterized in that, The line width b of the metal line (12) satisfies: 0.1mm≤b≤0.35mm, and the line height c of the metal line (12) satisfies: 5μm≤c≤10μm.

8. The washable flexible fabric circuit board according to claim 1, characterized in that, The resistance value R of each of the metal lines (12) satisfies: 19Ω≤R≤35Ω.

9. A wearable medical device, characterized in that, include: The washable flexible fabric circuit board as described in any one of claims 1-8.

10. A method for preparing a washable flexible fabric circuit board, characterized in that, The preparation method includes: Metal circuits are printed on a flexible substrate (12); The flexible substrate is embedded in the fabric gaps of the fabric substrate (11) by hot pressing process, so that the metal circuit (12) is transferred to the fabric substrate (11). Multiple electrodes (200) are mounted on a fabric substrate (11) such that each electrode (200) is electrically connected to a corresponding metal line (12); Each of the electrodes (200) is shielded, and the fabric substrate (11) is immersed in a hydrophobic coating to cover the outer periphery of the fabric substrate (11) and the metal circuit (12) with a hydrophobic coating.

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