Wearable medical monitoring equipment electrode

Abstract

The invention discloses a wearable medical monitoring equipment electrode which is composed of a layered structure and comprises a transparent flexible substrate layer which is made of a biocompatible flexible polymer material and is used for providing flexible support and isolating a metal electrode from the skin; the metal grid copper transparent electrode layer is formed on the surface of the transparent flexible substrate layer through a yellow light etching micro-nano processing technology; the conductive gel layer uniformly covers the surface of the metal grid copper electrode layer; the encapsulation layer is formed by spin-coating a polymethyl methacrylate solution on the surface of the conductive gel layer and forming a transparent protection layer after curing; the gradient line width bionic honeycomb-shaped copper grid design is adopted, the light transmittance is kept, meanwhile, the collection efficiency of physiological electric signals is remarkably improved, signal transmission loss is reduced, through the polyacrylamide and nanocellulose composite gel formula and micro-channel dynamic humidity adjustment, signal stability under long-term wearing is ensured, and the application range is wide. The problem of signal distortion caused by dryness of traditional gel is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrodes, and specifically to an electrode for a wearable medical monitoring device. Background Art

[0002] Wearable medical monitoring devices have shown broad application prospects in the fields of health management, disease diagnosis, and remote monitoring. In the development process of wearable medical monitoring devices, as a key component, the performance of the electrode directly affects the monitoring accuracy and user experience of the device. Currently, there are some problems that need to be solved urgently with the electrodes of wearable medical devices on the market.

[0003] Traditional metal electrodes, such as silver or silver chloride electrodes, although having certain advantages in conductivity and biocompatibility, are prone to corrosion by sweat, etc. during long-term use, resulting in unstable signal transmission, and also have relatively high costs; some electrodes based on carbon materials, although having lower costs and certain flexibility, have poor conductivity and are difficult to meet the requirements for high-precision acquisition of weak physiological electrical signals. In addition, when the existing electrodes are attached to the human skin, due to the lack of sufficient flexibility and breathability, the user's wearing comfort is poor, and they cannot be stably worn for a long time, affecting the continuity and accuracy of monitoring. Summary of the Invention

[0004] The purpose of the present invention is to provide an electrode for a wearable medical monitoring device to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: An electrode for a wearable medical monitoring device, which is composed of a layered structure, including:

[0006] A transparent flexible base layer, made of a biocompatible flexible polymer material, with a thickness of 0.05 - 0.8 mm, for providing flexible support and isolating the metal electrode from the skin;

[0007] A metal mesh copper transparent electrode layer, formed on the surface of the transparent flexible base layer through yellow light etching micro-nano processing technology, with the line width of its metal mesh being 1 - 50 μm, the spacing being 100 - 500 μm, the thickness being 0.1 - 5 μm, and the light transmittance being not less than 80%;

[0008] A conductive gel layer, composed of polyacrylamide, sodium chloride, glycerol, and deionized water, with a thickness of 0.1 mm, uniformly covering the surface of the metal mesh copper electrode layer;

[0009] An encapsulation layer, formed by spin-coating a polymethyl methacrylate solution on the surface of the conductive gel layer and curing it to form a transparent protective layer.

[0010] Preferably, the material of the transparent flexible base layer is one of polydimethylsiloxane, polyurethane or thermoplastic elastomer, and a micron-scale groove array is preset on the surface of the base, and the groove depth is 10%-30% of the base thickness, which is used to enhance the anchoring effect of the conductive gel layer.

[0011] Preferably, the grid pattern of the metal grid copper transparent electrode layer is a bionic honeycomb-like structure, wherein the grid line width changes in a gradient from the electrode edge to the central region, the edge line width is 10-50 μm, and the center line width is 1-10 μm, so as to optimize the mechanical strength of the electrode edge region and the light transmittance of the central region.

[0012] Preferably, the raw materials for preparing the conductive gel layer include 5%-15% of polyacrylamide, 0.5%-3% of sodium chloride, 10%-25% of glycerol by mass percentage, and the balance is deionized water, and 0.1%-1% of nanocrystalline cellulose is added to the gel by mass fraction, which is used to improve the viscoelasticity and anti-drying performance of the gel.

[0013] Preferably, 0.05%-0.5% of silicon dioxide nanoparticles with a particle size of 10-100 nm are incorporated into the polymethyl methacrylate solution of the encapsulation layer, which is used to improve the wear resistance and scratch resistance of the encapsulation layer.

[0014] Preferably, a transition layer is provided between the metal grid copper transparent electrode layer and the conductive gel layer. The transition layer is a micro-nano rough surface formed by plasma treatment, and the roughness Ra is 0.1-1 μm, which is used to enhance the interfacial bonding strength.

[0015] Preferably, an integrated flexible circuit interface is provided in the edge region of the transparent flexible base layer. The interface adopts a serpentine trace design, the line width is 50-200 μm, and the trace spacing is 100-500 μm, which is used to connect an external signal processing module and adapt to bending deformation.

[0016] Preferably, a microchannel structure is embedded in the conductive gel layer. The microchannel width is 10-100 μm and the depth is 5-50 μm. The dynamic humidity regulation function of the gel layer is realized by injecting an electrolyte solution.

[0017] Preferably, a hydrophobic coating is coated on the surface of the encapsulation layer, which is made of a blend of fluorinated siloxane and polydimethylsiloxane, and the thickness is 0.5-5 μm, which is used to prevent sweat penetration and reduce surface adhesion.

[0018] Preferably, the preparation method of the electrode includes the following steps:

[0019] S1: Prepare a metal grid copper electrode layer on the surface of the transparent flexible substrate by photolithography and wet etching processes;

[0020] S2: Perform oxygen plasma treatment on the metal grid copper electrode layer to form a micro-nano rough transition layer;

[0021] S3: Uniformly coat the surface of the transition layer with the conductive gel solution by spraying method and dry and cure it at room temperature;

[0022] S4: Form a poly(methyl methacrylate) solution encapsulation layer doped with silica nanoparticles on the surface of the conductive gel layer by spin coating method;

[0023] S5: Cure the encapsulation layer in an oven at 60 - 80 °C to finally obtain a flexible electrode with a multi-layer composite structure.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. The present invention adopts a gradient line width bionic honeycomb-shaped copper grid design, which significantly improves the acquisition efficiency of physiological electrical signals while maintaining the light transmittance, reduces the signal transmission loss, and ensures the signal stability under long-term wearing through the polyacrylamide and nanocellulose composite gel formula and the dynamic humidity regulation of the microchannel, solving the problem of signal distortion caused by the drying of traditional gels.

[0026] 2. The poly(methyl methacrylate) solution encapsulation layer doped with silica nanoparticles in the present invention acts synergistically with the hydrophobic coating to effectively isolate sweat corrosion, extend the service life of the electrode, and overcome the defects of easy corrosion and high cost of silver and silver chloride electrodes.

[0027] 3. Through the matching design of the transparent flexible substrate layer and the metal grid copper electrode layer in the present invention, the electrode can be closely attached to the skin surface, avoiding the problem of poor contact caused by movement of traditional rigid electrodes. The breathable structure of the metal grid and the humidity regulation function of the microchannel in the gel layer reduce the skin stuffiness and improve the wearing comfort. Description of the Drawings

[0028] Figure 1 It is a flow chart for the preparation of the electrode of the wearable medical monitoring device of the present invention.

[0029] Figure 2 It is a flow chart for the preparation of the metal grid copper electrode layer of the present invention.

[0030] Figure 3 It is a flow chart for the dynamic humidity regulation of the conductive gel layer of the present invention.

[0031] Figure 4 It is a flow chart for the preparation of the encapsulation layer and the hydrophobic coating of the present invention. Detailed Embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] Please refer to Figures 1 to 4 , the present invention provides a technical solution: a wearable medical monitoring device electrode, which is composed of a layered structure and includes:

[0034] A transparent flexible base layer, made of a biocompatible flexible polymer material, with a thickness of 0.05 - 0.8 mm. This thickness range not only ensures that the base has sufficient flexibility to closely fit the human skin and adapt to various human movement postures, such as bending, stretching, and twisting, but also ensures that it has a certain mechanical strength to prevent easy breakage during daily use.

[0035] The material of the transparent flexible base layer is one of polydimethylsiloxane, polyurethane, or thermoplastic elastomer, and a micron-level groove array is preset on the surface of the base. The groove depth is 10% - 30% of the base thickness. The grooves are designed to enhance the mechanical anchoring of the subsequent conductive gel layer and prevent delamination between layers.

[0036] An integrated flexible circuit interface is provided in the edge area of the transparent flexible base layer and is connected to the base through a hot pressing process. The interface adopts a serpentine trace design, with a line width of 50 - 200 μm and a trace spacing of 100 - 500 μm, for connecting to an external signal processing module and adapting to bending deformation.

[0037] The flexible base not only provides flexible support for the entire electrode but also isolates the metal grid copper electrode layer from the human skin to a certain extent, avoiding possible adverse reactions of metal allergy.

[0038] A metal grid copper transparent electrode layer is formed on the surface of the transparent flexible base layer through yellow light etching micro-nano processing technology. The line width of its metal grid is 1 - 50 μm, the spacing is 100 - 500 μm, and the thickness is 0.1 - 5 μm, and the light transmittance is not less than 80%; in the yellow light etching process, photoresist is spin-coated on the surface of the base, and through ultraviolet exposure, with a wavelength of 365 nm and an energy of 200 - 400 mJ / cm 2 , after development, a grid pattern mask is formed.

[0039] The grid pattern of the metal grid copper transparent electrode layer is a bionic honeycomb structure, in which the line width of the grid changes in a gradient from the electrode edge to the central area. The edge line width is 10 - 50 μm, and the center line width is 1 - 10 μm, to optimize the mechanical strength of the electrode edge area and the light transmittance of the central area.

[0040] There is a transition layer between the metal mesh copper transparent electrode layer and the conductive gel layer. The transition layer treatment is to perform oxygen plasma treatment on the surface of the copper mesh, with a power of 50 - 100W and a time of 30 - 120 seconds. The micro-nano rough surface formed by plasma treatment has a roughness Ra of 0.1 - 1μm, which improves the interfacial bonding strength with the conductive gel layer.

[0041] The conductive gel layer is composed of polyacrylamide, sodium chloride, glycerol and deionized water, with a thickness of 0.1 mm, and uniformly covers the surface of the metal mesh copper electrode layer;

[0042] The raw materials for preparing the conductive gel layer include 8% polyacrylamide, 1.5% sodium chloride, 18% glycerol, 0.5% nanocrystalline cellulose and 72% deionized water by mass percentage. Nanocrystalline cellulose is used to improve the viscoelasticity and anti-drying performance of the gel.

[0043] The conductive gel layer is embedded with a microchannel structure. The width of the microchannel is 10 - 100μm and the depth is 5 - 50μm. The dynamic humidity regulation function of the gel layer is realized by injecting an electrolyte solution.

[0044] The gel solution is evenly covered on the copper mesh surface by spraying method, with a nozzle diameter of 50μm and a pressure of 0.1 - 0.3MPa, and the thickness is controlled at 0.1mm; it is dried at room temperature for 1 hour to form a gel layer with a viscoelastic modulus of 0.1 - 1kPa.

[0045] The high conductivity of the metal mesh copper electrode layer greatly improves the acquisition efficiency of human physiological electrical signals, effectively reducing the loss and distortion during signal transmission. Cooperating with the conductive gel layer further reduces the contact resistance, making the monitoring data more accurate and reliable.

[0046] The encapsulation layer is formed by spin-coating a polymethyl methacrylate solution on the surface of the conductive gel layer and curing it to form a transparent protective layer.

[0047] The polymethyl methacrylate solution is dissolved in chloroform with a concentration of 5% - 10%, doped with 0.2% silica nanoparticles with a particle size of 30nm. Through spin-coating method, with a rotation speed of 2000rpm and a time of 30 seconds, an encapsulation layer with a thickness of 5μm is formed to improve the wear resistance and scratch resistance of the encapsulation layer.

[0048] The surface of the encapsulation layer is coated with a hydrophobic coating, which is made by blending fluorinated siloxane and polydimethylsiloxane, with a thickness of 2μm, to prevent sweat penetration and reduce surface adhesion.

[0049] The flexible substrate and highly flexible metal grid copper electrode layer can perfectly fit the various curved surfaces of human skin. Whether it is daily activities or strenuous exercise, the electrodes can maintain stable contact with the skin deformation without producing an obvious foreign body sensation. At the same time, the breathable structure of the metal grid and the moisturizing ingredients in the conductive gel greatly improve the wearing comfort, making it suitable for users to wear continuously for a long time, meeting the needs of wearable medical devices for long-term monitoring.

[0050] The protective effect of the encapsulation layer effectively extends the service life of the electrode, prevents the metal grid copper electrode layer from being corroded and the conductive gel layer from losing water, ensures that the electrode can work stably under various environmental conditions, and reduces the maintenance cost of the equipment.

[0051] The method for preparing the electrode comprises the following steps:

[0052] S1: Prepare a metal grid copper electrode layer on the surface of a transparent flexible substrate by photolithography and wet etching process;

[0053] S2: treating the metal grid copper electrode layer with oxygen plasma to form a micro-nano rough transition layer;

[0054] S3: uniformly coating the conductive gel solution on the surface of the transition layer by spraying, and drying and curing at room temperature;

[0055] S4: forming a polymethyl methacrylate solution encapsulation layer doped with silicon dioxide nanoparticles on the surface of the conductive gel layer by spin coating;

[0056] S5: Curing the encapsulation layer in an oven at 60-80°C to finally obtain a flexible electrode with a multi-layer composite structure.

[0057] When the electrode comes into contact with human skin, the weak physiological electrical signals generated by the human body are first transmitted to the metal grid copper electrode layer through the conductive gel layer. Due to the good conductivity of the conductive gel layer and its close fit with the skin, the contact resistance of signal transmission can be effectively reduced. The metal grid copper electrode layer, with its excellent high conductivity, transmits the physiological electrical signals quickly and stably to the signal processing module of the connected wearable medical monitoring device.

[0058] During this process, the high flexibility of the metal grid copper electrode layer ensures that even when the human body is in motion, the electrode and the skin can always maintain good contact, avoiding signal interruption or instability due to relative displacement. Its transparency facilitates the coordinated work of multiple monitoring functions in some application scenarios that require optical monitoring methods, such as skin blood oxygen monitoring, without interfering with each other.

[0059] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An electrode of a wearable medical monitoring device, characterized in that: The electrode is composed of a layered structure, including: A transparent flexible base layer, made of a biocompatible flexible polymer material, with a thickness of 0.05 - 0.8 mm, used to provide flexible support and isolate the metal electrode from the skin; A metal mesh copper transparent electrode layer, formed on the surface of the transparent flexible base layer by yellow light etching micro-nano processing technology, with a line width of 1 - 50 μm, a spacing of 100 - 500 μm, a thickness of 0.1 - 5 μm for the metal mesh, and a light transmittance of not less than 80%; A conductive gel layer, composed of polyacrylamide, sodium chloride, glycerol and deionized water, with a thickness of 0.1 mm, uniformly covering the surface of the metal mesh copper electrode layer; An encapsulation layer, formed by spin-coating a polymethyl methacrylate solution on the surface of the conductive gel layer and curing it to form a transparent protective layer.

2. The electrode of a wearable medical monitoring device according to claim 1, wherein: The material of the transparent flexible base layer is one of polydimethylsiloxane, polyurethane or thermoplastic elastomer, and a micro-scale groove array is preset on the surface of the base, with a groove depth of 10% - 30% of the base thickness, used to enhance the anchoring effect of the conductive gel layer.

3. The electrode of a wearable medical monitoring device according to claim 1, wherein: The grid pattern of the metal mesh copper transparent electrode layer is a bionic honeycomb structure, where the line width of the grid changes in a gradient from the electrode edge to the central region, with an edge line width of 10 - 50 μm and a central line width of 1 - 10 μm, to optimize the mechanical strength of the electrode edge region and the light transmittance of the central region.

4. The electrode of a wearable medical monitoring device according to claim 1, wherein: The raw materials for preparing the conductive gel layer include 5% - 15% of polyacrylamide, 0.5% - 3% of sodium chloride, 10% - 25% of glycerol by mass percentage, and the balance is deionized water, and 0.1% - 1% of nanocellulose crystals by mass fraction are added to the gel to improve the viscoelasticity and anti-drying performance of the gel.

5. The electrode of a wearable medical monitoring device according to claim 1, characterized in that: 0.05% - 0.5% of silicon dioxide nanoparticles by mass fraction are incorporated into the polymethyl methacrylate solution of the encapsulation layer, with a particle size of 10 - 100 nm, used to improve the wear resistance and scratch resistance of the encapsulation layer.

6. The electrode of a wearable medical monitoring device according to claim 1, wherein: A transition layer is provided between the metal mesh copper transparent electrode layer and the conductive gel layer, and the transition layer is a micro-nano rough surface formed by plasma treatment, with a roughness Ra of 0.1 - 1 μm, used to enhance the interfacial bonding strength.

7. The electrode of a wearable medical monitoring device according to claim 1, wherein: An integrated flexible circuit interface is provided at the edge region of the transparent flexible base layer, and the interface adopts a serpentine trace design, with a line width of 50 - 200 μm and a trace spacing of 100 - 500 μm, used to connect to an external signal processing module and adapt to bending deformation.

8. The electrode of a wearable medical monitoring device according to claim 1, characterized in that: A microchannel structure is embedded in the conductive gel layer, with a microchannel width of 10 - 100 μm and a depth of 5 - 50 μm, and the dynamic humidity adjustment function of the gel layer is realized by injecting an electrolyte solution.

9. The electrode of a wearable medical monitoring device according to claim 1, wherein: A hydrophobic coating is coated on the surface of the encapsulation layer, made of a blend of fluorinated siloxane and polydimethylsiloxane, with a thickness of 0.5 - 5 μm, used to prevent sweat penetration and reduce surface adhesion.

10. The electrode of a wearable medical monitoring device according to claim 1, wherein: The preparation method of the electrode includes the following steps: S1: Prepare a metal mesh copper electrode layer on the surface of the transparent flexible base by photolithography and wet etching processes; S2: Perform oxygen plasma treatment on the metal mesh copper electrode layer to form a micro-nano rough transition layer; S3: Uniformly coat the conductive gel solution on the surface of the transition layer by spraying method, and dry and cure it at room temperature; S4: Form a poly(methyl methacrylate) solution encapsulation layer doped with silicon dioxide nanoparticles on the surface of the conductive gel layer by spin coating method; S5: Cure the encapsulation layer in an oven at 60 - 80 °C to finally obtain a flexible electrode with a multi-layer composite structure.

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