Flexible electrode capable of adjusting detection position in real time

Abstract

The invention relates to a flexible electrode capable of adjusting a detection position in real time, which is used for solving the problem that after an existing fixed structure type electrode is attached, the detection position cannot be adjusted to quickly and accurately position a disease position or target nerves and muscles. And the problems of time waste, material waste, electrode performance reduction, skin discomfort or injury and the like caused by electrode replacement or electrode re-attachment due to detection position change are solved. The electrode is composed of a flexible substrate with a hole structure, a conductive magnetic fluid and a flexible packaging layer. After the electrode is attached to the skin, the encapsulation layer area corresponding to the conductive magnetic fluid is pressed, and the conductive magnetic fluid is pressed to penetrate through the holes in the flexible substrate to be in contact with the skin for signal acquisition. The conductive magnetofluid can be sucked back to the cavity space between the substrate and the packaging layer from the through holes by using the magnet; when the detection position needs to be changed, the conductive magnetofluid moves between the substrate and the packaging layer by using the magnet, so that the electrodes are attached once, and the detection position is adjusted at any time.

Description

Technical Field

[0001] This case relates to electrophysiological detection and monitoring technologies, and particularly to a flexible electrode with a real-time adjustable detection position. Background Art

[0002] Electrophysiological signal monitoring plays a crucial role in modern medical and technological applications, and is widely used in multiple fields such as disease diagnosis, treatment effect evaluation, rehabilitation process tracking, human-computer interaction, and health management and prevention. In the field of medical health, high-quality electrophysiological signal monitoring can improve the timeliness and accuracy of disease diagnosis, help doctors quickly find the cause, and thus formulate appropriate treatment plans to enhance the effectiveness of rehabilitation treatment. In the field of human-computer interaction, accurate acquisition of electrophysiological signals of targeted nerves or muscles can improve the accuracy of intention recognition, enhance the interaction experience, and thus enhance the reliability of human-computer interaction applications. As the core tool for collecting neuroelectrophysiological signals, the signal acquisition ability and usage experience of electrodes are crucial for the actual applications based on electrophysiological signals at the backend.

[0003] Although conventional electrodes can already collect high-quality electrophysiological signals, there are significant limitations in the existing electrode technologies in terms of achieving accurate signal acquisition and usage experience. Since physiological signals of the human body are often formed by the superposition of multiple muscles or neurons and are highly complex, and the state, size, etc. of human tissues vary from person to person, it is difficult to accurately attach the electrode to an individual at one time and accurately collect electrophysiological signals. In addition, during the detection of neuromuscular-related diseases, it is often necessary to adjust the electrode position multiple times to accurately locate the disease site. Traditional electrodes usually have a fixed structure and are difficult to flexibly adjust the position once attached to the skin or tissue surface, and it is difficult to obtain the best signal monitoring site or high-quality signals at one time. For this reason, it is often necessary to tear off the electrode and reattach it or directly replace the electrode, which not only increases the complexity of the operation, but also greatly increases the material cost and time cost. In addition, frequent tearing and pasting operations may also cause skin discomfort or damage, such as pain, skin redness and swelling, and allergic reactions, which not only affect the electrode wearing experience, but also reduce the reliability and stability of signal acquisition. Therefore, developing reliable electrodes to achieve rapid and accurate acquisition of electrophysiological signals at different positions while avoiding repeated pasting and frequent replacement of electrodes is of great significance for improving the electrode wearing experience, achieving accurate disease diagnosis and treatment, and high-quality human-computer interaction.

[0004] In order to accurately collect the electrophysiological signals of targeted nerves or muscle tissues in an area without repeatedly pasting electrodes or replacing electrodes, multi-channel electrode arrays and movable electrodes have been developed. The multi-channel electrode array contains multiple independent detection channels within a certain area. After being attached once, it can collect electrophysiological signals at multiple positions simultaneously without changing its position, thereby enabling rapid localization of the disease location or targeted nerves. However, due to the large number of channels in this type of electrode, the structural complexity and cost of both the electrode and the acquisition device have increased significantly. Summary of the Invention

[0005] Aiming at the above problems or some of them, the purpose of this solution is to propose a new flexible electrode structure design with a real-time adjustable detection position. By designing and fabricating a magneto-conductive fluid detection layer that can move arbitrarily, not only can the detection position of the electrode be arbitrarily changed without changing the overall position of the electrode, but also the electrode substrate can be stably adhered to the skin to ensure high-quality signal detection, while avoiding the discomfort and damage caused by the de-adhesion of the electrode to the skin when changing positions.

[0006] In a first aspect, the present disclosure proposes a flexible electrode with a real-time adjustable detection position. The flexible electrode includes a magneto-conductive fluid, a substrate, and a packaging layer. The substrate and the packaging layer form a cavity together, confining the magneto-conductive fluid within the cavity. The magneto-conductive fluid is a semi-solid conductive material that can deform and move under the action of an external force or a magnetic field. The substrate has holes. By pressing the surface of the packaging layer corresponding to the magneto-conductive fluid, the magneto-conductive fluid is extruded, and a part of it penetrates through several holes to contact the skin, collecting the electrophysiological signals of the skin. The magneto-conductive fluid that penetrates through the holes can return to the cavity space under the action of a magnetic field. The substrate is a flexible and stretchable polymer film, and its adhesion to the skin is not only greater than the gravity of the electrode itself but also greater than the adhesion of the magneto-conductive fluid to the skin, thereby ensuring that the flexible electrode can stably collect signals under different skin conditions. In one implementation of the above technical solution, a wire is used to connect the magneto-conductive fluid to an external device.

[0007] In one implementation of the above technical solution, the components of the magneto-conductive fluid include a solvent, a polymer, magnetic particles, a conductive material, and an additive. The mass percentages of each component are 35% - 65%, 2% - 18%, 15% - 40%, 0% - 25%, and 0.1% - 10% respectively. The solvent is water or ethanol. The polymer is polyethylene glycol, dextran, polyvinylpyrrolidone, or liquid silicone. The magnetic particles are iron oxide, iron tetroxide, nickel, or neodymium iron boron powder. The conductive material is metal particles, carbon materials, or conductive polymers. The additive is a polymer cross-linking agent, glycerol, polyethylene glycol, sodium chloride, or potassium chloride.

[0008] In one embodiment of the above technical solution, the material of the flexible and stretchable polymer film is one or more of the following composites: polyurethane, silicone rubber, fluororubber, styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene block polymer with isoprene substituting butadiene (SIS), and parylene.

[0009] In one embodiment of the above technical solution, the thickness of the flexible and stretchable polymer film is 100 nm - 10 mm.

[0010] In one embodiment of the above technical solution, the magnetic field is provided by a magnet.

[0011] In one embodiment of the above technical solution, the holes are regular shapes, irregular shapes, or a combination of regular and irregular shapes, and the area is , and the edge distance between the holes and adjacent holes is 0.1 µm - 10 mm.

[0012] In one embodiment of the above technical solution, there are multiple electromagnetic fluids.

[0013] In a second aspect, the present disclosure provides a flexible electrode. The flexible electrode includes a cavity, and the bottom of the cavity adheres to the skin through its own physical action or an adhesive; there is an electromagnetic fluid in the cavity. Pressing the surface of the cavity corresponding to the position where the electromagnetic fluid is located can enable the electromagnetic fluid to contact the skin through the holes at the bottom of the cavity, and collect the electrophysiological signals of the skin.

[0014] In one embodiment of the above technical solution, the bottom of the cavity uses a flexible and stretchable polymer film, and its adhesion to the skin is not only greater than the weight of the electrode itself, but also greater than the adhesion of the electromagnetic fluid to the skin.

[0015] Advantageous technical effects: The electrode designed and prepared in the present disclosure only needs to be attached once, and the detection position can be adjusted at any time, avoiding material waste and time consumption when replacing the electrode and adjusting the detection position, and can reduce possible skin discomfort, damage, etc. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 , OneSchematic diagram of a flexible electrode with a real-time adjustable detection position in one embodiment.

[0018] Figure 2 、 One Schematic diagram of the movement of the ferrofluid in the flexible electrode with a real-time adjustable detection position in one embodiment by the attraction of a magnet.

[0019] Figure 3 、 One Schematic diagram before being pressed in one embodiment.

[0020] Figure 4 、 One Schematic diagram after being pressed in one embodiment.

[0021] Figure 5 、 One Schematic diagram of the electromyogram (EMG) signal measured before the ferrofluid moves in one embodiment.

[0022] Figure 6 、 One Schematic diagram of the EMG signal measured after the ferrofluid moves in one embodiment.

[0023] In the figure: ① Encapsulation layer, ② Conductive ferrofluid, ③ Substrate, ④ Lead wire, ⑤ Magnet, ⑥ Skin. Specific embodiments

[0024] Based on the background technology, the following problems exist in the prior art: The existing fixed-structured electrodes cannot change the detection position after attachment, making it difficult to quickly and accurately monitor the signals of targeted nerves or muscles or locate the disease position; Although the existing multi-channel electrodes can simultaneously test the electrophysiological signals at multiple positions in a large area for accurate positioning, the multi-channel electrodes have a high cost and require high complexity and performance of the acquisition equipment; The existing body surface electrodes with movable positions have insufficient adhesion and stability on the body surface, making it difficult to achieve reliable use in different skin states and positions.

[0025] This case proposes a flexible electrode structure design with a real-time changeable position, which can, without changing the overall electrode position after a single attachment, arbitrarily change the electrode detection position by adjusting the position of the conductive ferrofluid to realize the detection of electrophysiological signals at any position within a large area, thus overcoming the problem that the traditional fixed-structured electrodes cannot adjust the position after attachment, as well as a series of problems such as time waste, material waste, skin discomfort or damage caused by replacing the electrode or re-attaching the electrode due to the need to change the detection position.

[0026] Next, in conjunction with the accompanying drawings, how the technical solution of this case is implemented will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of this case, rather than all embodiments. Based on the embodiments in this case, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by this application.

[0027] (I) Structural design of the electrode The electrode includes a substrate, a conductive electromagnetic fluid, and a packaging layer. The substrate, the conductive electromagnetic fluid, and the packaging layer form a "sandwich" structure, where: the substrate and the packaging layer are combined to form a cavity, confining the conductive electromagnetic fluid within the cavity. The substrate is located at the bottom of the electrode and directly contacts the skin. The packaging layer is located at the upper part of the electrode, and its edge can be assembled with the flexible substrate. The assembly method can be adhesion or other detachable methods. A cavity space is formed between the packaging layer and the substrate. Within this space, the conductive electromagnetic fluid, which serves as the sensing and detecting part of the electrode, is confined.

[0028] The conductive electromagnetic fluid can move freely, without leakage and without contacting the external environment. There are holes on the substrate. Before the electrode is used, due to its relatively high viscosity, the conductive electromagnetic fluid can stay on the flexible substrate and will not leak through the holes on the substrate or contact the skin, that is, the conductive electromagnetic fluid is separated from the skin by the substrate. After the electrode is attached to the skin, by pressing the area of the packaging layer above the conductive electromagnetic fluid, the conductive electromagnetic fluid is pressed to pass through the holes on the substrate and contact the skin, and then physiological electrical signal acquisition can be carried out.

[0029] After the signal acquisition is completed, a magnet or a real-time generated magnetic field can be used to suck the conductive electromagnetic fluid back into the cavity space between the substrate and the packaging layer through the holes on the substrate.

[0030] When changing the detection position, a magnet or a real-time generated magnetic field can be used to change the position of the conductive electromagnetic fluid between the substrate and the packaging layer, and then by pressing, the conductive electromagnetic fluid passes through the holes on the substrate and contacts the skin for signal detection. This realizes that with one attachment of the electrode, the position can be adjusted at any time to perform electrophysiological signal detection within a certain area, avoiding the problems of fixed acquisition points and immobility of conventional electrodes, high cost of multi-channel electrodes and complex acquisition equipment, and poor stability of existing movable electrodes on the body surface.

[0031] See Figure 1 the shown electrode, which is composed of a substrate ③, a conductive electromagnetic fluid ②, and a packaging layer ①. There are regularly arranged circular holes on the substrate, but the size, shape, and arrangement of the holes can be further designed. The conductive electromagnetic fluid is connected to an external device through a wire ④. See Figure 2 , a magnet can be used to change the position of the conductive electromagnetic fluid, Figure 2In (a), it shows the position before changing the position of the magneto-conductive fluid by using a magnet. Figure 2 In (b), it shows the position after the right magneto-fluid in the two magneto-fluids is moved to the right by the magnet. See Figure 3 and Figure 4 , which are the states of the magneto-conductive fluid before and after pressing respectively. Before pressing, the magneto-conductive fluid is located between the substrate and the encapsulation layer. After pressing, the magneto-conductive fluid is squeezed into several holes to contact the skin ⑥.

[0032] Thus, it can be seen that when the electrode substrate adheres to the skin in this case, the detection position of the electrode can be changed without changing the overall position of the electrode, thereby avoiding the material and time costs of replacing the electrode and the detection position, and can also reduce skin discomfort, damage, etc.

[0033] When the entire cavity space formed by the substrate and the encapsulation layer is filled with magneto-conductive fluid, signal acquisition of the skin area covered by the entire electrode area can be realized. If a magnet or magnetic field is set on the encapsulation layer, it can control whether the magneto-conductive fluid contacts the skin. Figure 2 The magnet ⑤ is used in

[0034] (II) Material Selection The substrate is preferably made of a flexible and stretchable thin film material, so that the substrate can form a certain adhesion force with the skin through physical or chemical action, and can be processed into a thin film structure with holes.

[0035] The encapsulation layer is preferably made of a flexible and stretchable thin film material, so that the prepared electrode can be overall soft, deformable and stretchable.

[0036] The magneto-conductive fluid material requires a high magnetic adsorption deformation ability, certain electrical conductivity, viscosity and shape retention. It has low adhesion to the skin, does not adhere to the substrate and the encapsulation layer. It will not spread through the holes of the flexible substrate by itself under static conditions, but can penetrate through the holes of the substrate to contact the skin after pressing. The interface impedance is low when contacting the skin, which not only ensures high-quality signals, but also avoids the discomfort and damage caused by the de-adhesion of the magneto-conductive fluid to the skin when changing positions.

[0037] The electrode assembled in this way is a flexible electrode that can closely fit the skin without causing discomfort.

[0038] (III) Preparation Method of the Electrode (3.1) Substrate The substrate is preferably a flexible and stretchable polymer thin film, which can form a strong adhesion force with the skin through its own physical action or adhesive.

[0039] Prepare a polymer film with a microporous structure. The thickness of the film is preferably between 100 nm and 10 mm (including the boundaries and any values within the boundaries), and the size and shape are not limited. The materials used are preferably flexible materials with good biocompatibility, including but not limited to one or more composites of polyurethane, silicone rubber, fluororubber, styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene block copolymer with isoprene substituting butadiene (SIS), parylene, etc. These materials can ensure that the adhesion force between the prepared substrate and the skin is greater than the gravity of the electrode itself and greater than the adhesion force between the electroconductive magnetic fluid and the skin, thereby ensuring that the flexible electrode can stably collect signals under different skin conditions.

[0040] The preparation methods of the film include but are not limited to printing, doctor blading, casting, spin coating, hot pressing, etc.; the micropores on the film can be regular shapes such as circular, square, triangular, or irregular shapes, or a combination of regular and irregular shapes. The pore sizes can be the same or different, and the area size is controlled within , and the edge distance between the holes and adjacent holes is 0.1 µm - 10 mm.

[0041] The accuracy of the flexible electrode in collecting signals with respect to the pore shape and spacing can be determined by simulation.

[0042] The micropores can be prepared by methods such as template method, mechanical cutting, laser cutting, etc.

[0043] One side of the substrate can be selectively coated with an adhesive, and the adhesive can be a biocompatible pressure-sensitive adhesive, silicone rubber, etc.

[0044] (3.2) Electroconductive magnetic fluid The electroconductive magnetic fluid is a semi-solid conductive material that can deform and move under the action of external force or magnetic field and can collect and conduct electrophysiological signals. Its adhesion force to the skin is less than the adhesion force between the above flexible stretchable film and the skin, so it is convenient to detach from the skin.

[0045] A conductive electromagnetic fluid is prepared by using components including a solvent, a polymer, magnetic particles, a conductive material, an additive, etc. The mass percentages of each component are 35% - 65%, 2% - 18%, 15% - 40%, 0% - 25%, and 0.1% - 10% respectively. The mass percentages of each component include the boundary values. Based on such mass percentages, the obtained conductive electromagnetic fluid can achieve a certain adhesion to the skin and is convenient to detach from the skin. Among them: the solvents used are water, ethanol, etc.; the polymers are polyethylene glycol, dextran, polyvinylpyrrolidone, liquid silicone, etc.; the magnetic particles are ferric oxide, ferroferric oxide, nickel, neodymium iron boron powder, etc.; the conductive materials are metal particles, carbon materials, conductive polymers, etc.; the additives are polymer crosslinking agents, glycerol, polyethylene glycol, sodium chloride, potassium chloride, etc.

[0046] The conductive electromagnetic fluid prepared thereby has high magnetic attraction deformation ability, certain viscosity and shape retention, low skin adhesion and interface impedance, and does not adhere to the substrate and the encapsulation layer, ensuring that the electrode can quickly change the detection position, does not damage the skin, and can obtain high-quality electrophysiological signals.

[0047] (3.3)Encapsulation layer A polymer film with the same shape and size as the flexible substrate is prepared. The thickness of the film is between 100 nm and 10 mm, and the materials used are flexible materials with good biocompatibility, including but not limited to one or more composites of polyurethane, silicone rubber, fluororubber, styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), isoprene-substituted butadiene block styrene polymer (SIS), parylene, etc.; the preparation methods of the film include but not limited to printing, scraping, printing, casting, spin coating, hot pressing, etc.

[0048] It should be noted that the material of the encapsulation layer can be different from that of the substrate layer.

[0049] (3.4)Electrode The conductive electromagnetic fluid is placed between the flexible substrate and the encapsulation layer, and then the wire is fixed to the edge of the substrate and connected to the conductive electromagnetic fluid and the acquisition device respectively. After that, the edges of the flexible substrate and the encapsulation layer are bonded to obtain a flexible electrode that can change positions in real time. Before using the electrode, the conductive electromagnetic fluid can stay on the flexible substrate due to its own viscosity and shape retention, and will not leak through the holes on the substrate or contact the skin.

[0050] When in use, after attaching the electrode to the skin, press the packaging layer area on the upper layer of the electromagnetic conductive fluid, so that the electromagnetic conductive fluid is pressurized and contacts the skin through the holes in the flexible substrate, and then collect signals; after a single test, use a magnet to suck the electromagnetic conductive fluid back into the cavity space between the packaging layer through the holes in the flexible substrate; when the detection position needs to be changed, use a magnet to attract the electromagnetic conductive fluid to change its position between the flexible substrate and the packaging layer, and then press the electromagnetic conductive fluid through the holes in the flexible substrate to contact the skin to achieve signal detection; after the final test, use a magnet to suck the electromagnetic conductive fluid out of the holes in the flexible substrate to the middle of the flexible substrate and the sealing layer.

[0051] 4. Experimental verification (4.1) Example 1 Preparation of flexible substrate: A 2 mm thick 5×5 cm film was prepared using silicone rubber Ecoflex by casting a template and curing it at room temperature. Then, evenly distributed circular through micropores with a diameter of 1 mm were generated on it by mechanical punching, and the spacing between the holes was 3 mm.

[0052] Preparation of magnetically conductive fluid: The magnetically conductive fluid was prepared using ferroferric oxide. The preparation method was as follows: (1) Weigh an appropriate amount of PVA powder and dissolve it in deionized water to obtain a PVA solution with a concentration of 15 wt%. (2) Weigh 4.58 g of ferroferric oxide (particle size of 100 nm, purity of 99%), 11.3 g of PVA solution, and 0.17 g of additive (PVA cross-linking agent borax) and mix them to obtain a solvent, polymer, magnetic particles, and additive with a proportion of 59.9%, 10.5%, 28.5%, and 1.1%, respectively. Then stir at room temperature at a speed of 2000 rpm for 2 minutes to ensure that the components are evenly mixed and the natural cross-linking of PVA is completed, and finally the magnetically conductive fluid is obtained.

[0053] Preparation of encapsulation layer: A 1 mm thick 5×5 cm film was prepared using silicone rubber Ecoflex by casting a template and curing at room temperature.

[0054] Assembly of electrodes: Take an appropriate amount of electromagnetically conductive fluid and place it between the flexible substrate and the packaging layer. Then fix the wires on the edge of the substrate and connect them to the electromagnetically conductive fluid and the collection device respectively. Then, bond the flexible substrate to the edge of the packaging layer to obtain a flexible electrode that can change its position in real time.

[0055] Usage of the electrode: After cleaning the skin on the arm, attach the electrode. Gently press the encapsulation layer area on the upper layer of the electro-conductive magnetic fluid with your hand. After the electro-conductive magnetic fluid is pressed and penetrates through the holes on the flexible substrate to contact the skin, signal acquisition is performed when the arm makes a fist clenching movement; after a single test, use a magnet to suck the electro-conductive magnetic fluid back into the cavity space between the flexible substrate and the encapsulation layer through the holes on the flexible substrate, change the position of the electro-conductive magnetic fluid between the flexible substrate and the encapsulation layer, then press the electro-conductive magnetic fluid to penetrate through the holes on the flexible substrate to contact the skin, and signal acquisition is performed when the arm makes a fist clenching movement again; after the final test, use a magnet to suck out the electro-conductive magnetic fluid to the middle of the flexible substrate and the encapsulation layer.

[0056] (4.2) Example 2 Preparation of the flexible substrate: Use silicone rubber Ecoflex to prepare a circular film with a thickness of 5 mm and a diameter of 6 cm by pouring it into a mold and curing it at room temperature. Then, use a mechanical punching method to generate uniformly distributed circular through-holes with a diameter of 500 nm on it, and the distance between holes is 1 mm.

[0057] Preparation of the electro-conductive magnetic fluid: Use iron oxide to prepare the electro-conductive magnetic fluid. The preparation method is as follows: (1) Weigh an appropriate amount of PVA powder and dissolve it fully in deionized water to obtain a PVA solution with a concentration of 15 wt%. (2) Weigh 5.5 g of iron oxide (particle size of 100 nm, purity of 99%), 11.5 g of the PVA solution, and 0.2 g of an additive (PVA cross-linking agent borax) respectively and mix them. The proportions of the solvent, polymer, magnetic particles, and additive are 56.83%, 10.03%, 31.98%, and 1.16% respectively. Then, stir at a speed of 2000 rpm for 2 minutes at room temperature to ensure uniform mixing of each component and complete the natural cross-linking of PVA. Finally, the electro-conductive magnetic fluid is obtained.

[0058] Preparation of the encapsulation layer: Use silicone rubber Ecoflex to prepare a circular film with a thickness of 2 mm and a diameter of 6 cm by pouring it into a mold and curing it at room temperature.

[0059] Assembly of the electrode: Take an appropriate amount of electro-conductive magnetic fluid and place it between the flexible substrate and the encapsulation layer. Then, fix the wire on the edge of the substrate and connect it to the electro-conductive magnetic fluid and the acquisition device respectively. After that, bond the edges of the flexible substrate and the encapsulation layer to obtain a flexible electrode whose position can be changed in real time.

[0060] Usage of the electrode: After cleaning the skin on the arm, attach the electrode. Gently press the encapsulation layer area on the upper layer of the electromagnetic fluid with your hand. After the electromagnetic fluid is pressed and penetrates through the holes on the flexible substrate to contact the skin, signal acquisition is carried out when the arm makes a fist clenching movement; after a single test, use a magnet to suck the electromagnetic fluid back into the cavity space between the flexible substrate and the encapsulation layer through the holes on the flexible substrate, change the position of the electromagnetic fluid between the flexible substrate and the encapsulation layer, then press the electromagnetic fluid to penetrate through the holes on the flexible substrate to contact the skin, and signal acquisition is carried out when the arm makes a fist clenching movement again; after the final test, use a magnet to suck out the electromagnetic fluid to the middle of the flexible substrate and the encapsulation layer.

[0061] (4.3) Example 3 Preparation of the flexible substrate: Use silicone rubber Ecoflex to prepare a circular film with a thickness of 5 mm and a diameter of 6 cm by pouring into a mold and curing at room temperature. Then, generate uniformly distributed circular through-holes with a diameter of 1 mm on it by mechanical punching, and the distance between holes is 3 mm.

[0062] Preparation of the electromagnetic fluid: Use iron oxide to prepare the electromagnetic fluid. The preparation method is as follows: (1) Weigh an appropriate amount of PVA powder and dissolve it fully in deionized water to obtain a PVA solution with a concentration of 20 wt%. (2) Weigh 4.46 g of iron oxide (particle size of 100 nm, purity of 99%), 0.51 g of carbon nanotubes, 12 g of the PVA solution, and 0.86 g of an additive (PVA crosslinking agent borax) respectively and mix them. The proportions of the solvent, polymer, magnetic particles, conductive material, and additive are 53.84%, 13.46%, 25.01%, 2.86%, and 4.82% respectively. Then, stir at a speed of 2000 rpm at room temperature for 2 minutes to ensure uniform mixing of each component, and finally obtain the electromagnetic fluid.

[0063] Preparation of the encapsulation layer: Use a 10% SEBS-toluene solution by spin coating to prepare a circular film with a thickness of 5 mm and a diameter of 6 cm.

[0064] Usage of the electrode: After cleaning the skin on the back, attach the electrode. Gently press the encapsulation layer area on the upper layer of the electromagnetic fluid with your hand. After the electromagnetic fluid is pressed and penetrates through the holes on the flexible substrate to contact the skin, signal acquisition is carried out when bending down; after a single test, use a magnet to suck the electromagnetic fluid back into the cavity space between the flexible substrate and the encapsulation layer through the holes on the flexible substrate.

[0065] (4.4) Example 4 Figure 5 and Figure 6 Schematic diagram showing the electromyogram signals of the electromagnetic fluid before and after movement when using the prepared flexible electrode. In the two figures,Figure 5 and Figure 6 where (a) in Figure 6 is the electromyogram signal of channel 1, Figure 5 and Figure 6 where (b) in Figure 6 is the electromyogram signal of channel 2. As can be seen from the two figures, the quality of the electromyogram signals of the two channels before and after moving the position is relatively high, and different signal forms are shown at different positions. The flexible electrode uses two electromagnetic fluid conductors.

[0066] However, in other embodiments, the number of electromagnetic fluid conductors in the cavity of the flexible electrode can be 1, 3 or more. The electromagnetic fluid conductor can be split into multiple ones under the condition of a magnetic field or manual extrusion, and can be positioned to the corresponding positions under the control of a magnetic field or external force to form an electrophysiological signal acquisition array. It will not make the electrode complicated due to the increase in the number of channels, thus reducing the cost of the device. Similarly, multiple electromagnetic fluid conductors can also be combined into one.

[0067] (4.5) Embodiment 5 When there is no need to adjust the detection position, the electromagnetic fluid conductor in the cavity of the flexible electrode can be 1, filling the cavity in area, and the height can meet the requirement of being sucked back from the hole into the cavity space.

[0068] The flexible electrode in this case can be used as a device or sensor for collecting physiological electrical signals, or can be used as a local electrical stimulation device.

[0069] Although the embodiments of the present disclosure have been described above in conjunction with the accompanying drawings, the present disclosure is not limited to the above specific embodiments and application fields. The above specific embodiments are merely illustrative and guiding, rather than restrictive. Those of ordinary skill in the art can also make many forms under the inspiration of this specification and without departing from the scope protected by the claims of the present disclosure, and these all fall within the scope of protection of the present disclosure.

Claims

1. A flexible electrode with real-time adjustable detection position, characterized in that: The flexible electrode comprises an electromagnetically conductive fluid, a substrate, and a packaging layer, wherein the substrate and the packaging layer are combined to form a cavity, and the electromagnetically conductive fluid is confined in the cavity; The electromagnetically conductive fluid is a semi-solid conductive material that can be deformed and moved under the action of an external force or magnetic field; The substrate has holes, and the surface of the packaging layer corresponding to the electromagnetically conductive fluid is pressed to squeeze the electromagnetically conductive fluid, so that the electromagnetically conductive fluid is partially in contact with the skin through the holes to collect the electrophysiological signals of the skin, and the electromagnetically conductive fluid that passes through the holes can return to the cavity space under the action of the magnetic field; The substrate is a flexible and stretchable polymer film, and its adhesion to the skin is not only greater than the gravity of the electrode itself, but also greater than the adhesion between the conductive electromagnetic fluid and the skin, thereby ensuring that the flexible electrode can stably collect signals under different skin conditions.

2. The flexible electrode according to claim 1, characterized in that: Use wires to connect the conductive magnetic fluid to external equipment.

3. The flexible electrode according to claim 1, characterized in that: The components of the electromagnetic fluid include solvent, polymer, magnetic particles, conductive material, and additives, and the mass proportions of each component are 35% to 65%, 2% to 18%, 15% to 40%, 0% to 25%, and 0.1% to 10%, respectively; the solvent is water or ethanol; the polymer is polyethylene glycol, dextran, polyvinyl pyrrolidone or liquid silica gel; the magnetic particles are ferric oxide, ferrous oxide, nickel or rubidium iron boron powder, the conductive material is metal particles, carbon material or conductive polymer, and the additive is a polymer cross-linking agent, propylene glycol, polyethylene glycol, sodium chloride or potassium chloride.

4. The flexible electrode according to claim 1, characterized in that: The material of the flexible and stretchable polymer film is one or more of the following composites: polyurethane, silicone rubber, fluororubber, styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), isoprene-substituted butadiene block styrene polymer (SIS), polyparaxylene.

5. The flexible electrode according to claim 1, characterized in that: The thickness of the flexible and stretchable polymer film is 100 nm-10 mm.

6. The flexible electrode according to claim 1, characterized in that: The magnetic field is provided by magnets.

7. The flexible electrode according to claim 1, characterized in that: The holes are of regular shape or irregular shape or a combination of regular shape and irregular shape, and the hole area is The distance between the edge of the hole and the adjacent hole is 0.1 µm-10 mm.

8. The flexible electrode according to claim 1, characterized in that: The number of the electromagnetically conductive fluids is multiple.

9. A flexible electrode, characterized in that: The flexible electrode comprises a cavity, the bottom of which adheres to the skin through its own physical action or adhesive; There is an electromagnetically conductive fluid in the cavity. By pressing the cavity surface corresponding to the position of the electromagnetically conductive fluid, the electromagnetically conductive fluid can contact the skin through the holes at the bottom of the cavity to collect electrophysiological signals of the skin.

10. The flexible electrode according to claim 9, characterized in that: The bottom of the cavity is made of a flexible and stretchable polymer film, and its adhesion to the skin is not only greater than the gravity of the electrode itself, but also greater than the adhesion between the conductive electromagnetic fluid and the skin.

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