WO2024027432A1

WO2024027432A1 - Electrocardiogram electrode and electronic device

Info

Publication number: WO2024027432A1
Application number: PCT/CN2023/105272
Authority: WO
Inventors: 金秋; 胡轶; 茹红强; 张翠萍
Original assignee: 华为技术有限公司
Priority date: 2022-08-05
Filing date: 2023-06-30
Publication date: 2024-02-08
Also published as: CN117547277A

Abstract

The embodiment of the present invention relates to the field of electrocardiogram detection devices. Disclosed are an electrocardiogram electrode and an electronic device, which solve the problem that the small effective contact area of existing electrocardiogram electrodes with the human body makes the signal quality stability of the electrocardiogram electrodes low. The electrocardiogram electrode comprises an electro-conductive ceramic layer and an electro-conductive layer. The electro-conductive ceramic layer has a first surface and a second surface opposite to each other. The first surface is used to be electrically connected to a lead. The electro-conductive layer is provided in a stacked manner on the second surface of the electro-conductive ceramic layer. Furthermore, the electro-conductive layer is electrically connected to the electro-conductive ceramic layer. The electro-conductive layer and the electro-conductive ceramic layer may be electrically connected directly, or may be electrically connected indirectly. The electro-conductive layer is used to be in contact with the skin to collect an electrical signal. The outer surface of the electro-conductive layer away from the electro-conductive ceramic layer may be in contact with the skin to form a whole-surface effective contact. Therefore, according to the present application, the electro-conductive layer is provided on the electro-conductive ceramic layer, so that the effective area of the electrocardiogram electrode in contact with the skin is increased. Moreover, the signal quality stability of the electrocardiogram electrode is improved.

Description

A kind of electrocardiographic electrode and electronic equipment

This application claims priority to the Chinese patent application filed with the China Patent Office on August 5, 2022, with the application number 202210939547.2 and the application name "An electrocardiographic electrode and electronic device", the entire content of which is incorporated into this application by reference. middle.

Technical field

The present application relates to the technical field of ECG detection equipment, and in particular to an ECG electrode and electronic equipment.

Background technique

More and more smart wearable devices use electrocardiogram (ECG) function as one of their main features. Therefore, users can monitor their heart health at any time through smart wearable devices during daily use. One of the core components of these smart wearable devices to implement the ECG detection function is the ECG electrode. Usually, ECG electrodes are installed on the appearance surface of smart wearable devices and can be in contact with human skin to collect the potential on the human body surface. Afterwards, the potential signal is transmitted to the internal processing device of the smart wearable device for further processing and analysis, thereby obtaining an electrocardiogram. The quality of the ECG electrodes greatly affects the signal quality of the ECG.

There is an existing ECG electrode made of conductive ceramics. Conductive ceramics can directly transmit human physiological signals to processors inside electronic devices. Conductive ceramics include a matrix phase and a conductive phase, and the conductive phase is dispersed in the matrix phase. The conductive phases are connected to each other into a conductive network structure to provide conductive properties. Only when the conductive phase in the conductive ceramic comes into contact with the human skin can the potential of the human body surface be collected. Therefore, only some areas on the surface of the conductive ceramic can form effective contact with the human skin. The effective contact area between the ECG electrode and the human body is small, resulting in low signal quality stability of the ECG electrode.

Contents of the invention

Embodiments of the present application provide an ECG electrode and electronic equipment, which solve the problem that the effective contact area between the existing ECG electrode and the human body is small, resulting in low signal quality stability of the ECG electrode.

In order to achieve the above purpose, this application adopts the following technical solutions:

In a first aspect, embodiments of the present application provide an electrocardiographic electrode including a conductive ceramic layer and a conductive layer. Wherein, the conductive ceramic layer has opposite first surfaces and second surfaces. The first surface is used for electrical connection with the wires. The conductive layer is stacked on the second surface of the conductive ceramic layer. Furthermore, the conductive layer is electrically connected to the conductive ceramic layer. The conductive layer and the conductive ceramic layer may be directly electrically connected or indirectly electrically connected. The conductive layer is used to make contact with the skin to collect electrical signals. The electrocardiographic electrode in the embodiment of the present application has a conductive layer added to the conductive ceramic layer. The outer surface of the conductive layer away from the conductive ceramic layer can all be in contact with the skin to form effective contact over the entire surface. Therefore, the effective area of contact between the ECG electrode and the skin is increased. Furthermore, the signal quality stability of the ECG electrode is improved.

In some embodiments, the material of the conductive layer is any one of nitride, carbide, and carbonitride of metal materials. Among them, the ratio of the content of non-metal elements to the content of metal elements in the conductive layer is greater than 1:9. A higher content of non-metallic elements in the conductive layer can give it a stable polarization potential. In addition, the conductive layer made of the above-mentioned materials is not easy to chemically react with sweat, so the conductive layer has good resistance to acid and alkali sweat corrosion.

Moreover, in other embodiments, the ratio of the content of non-metal elements to the content of metal elements in the conductive layer is greater than 1:4. In the same way, increasing the content of non-metallic elements in the conductive layer can further improve the polarization potential stability of the conductive layer.

Based on the above, in some embodiments of the present application, the material of the conductive layer is any one of TiC, TiN, TiCN, CrC, CrN, CrCN, TiNbN, and TiNbC. All of the above-mentioned materials can have stable polarization potential, and have good resistance to acid and alkali sweat corrosion.

Moreover, in order to further improve the corrosion resistance of the conductive layer, in some embodiments, the material of the conductive layer further includes silicon element. For example, the material of the conductive layer is any one of CrSiN, CrSiC, TiSiN, TiSiC, CrSiCN, and TiSiCN. These materials have stronger resistance to acid and alkali sweat corrosion.

Furthermore, in some embodiments of the present application, the thickness of the conductive layer is greater than or equal to 0.4 μm. A conductive layer of sufficient thickness can ensure a stable polarization potential and is not prone to chemical reactions with sweat.

The above is mainly the selection of materials and various physical parameters of the conductive layer. The various physical parameters of the conductive ceramic layer also need to be appropriately selected. In some embodiments of the present application, the conductive ceramic layer has a resistivity of less than 10 ^-4 Ω·m. The ECG signal passes through conductive ceramics with small resistivity When the porcelain layer is used, the resistance is small, which facilitates the transmission of ECG signals.

Since the conductive ceramic layer will produce certain pores during production, electrons will scatter more and generate noise when passing through the pores in the conductive ceramic layer, which is not conducive to obtaining stable ECG signals. Therefore, in some embodiments of the present application, the porosity of the conductive ceramic layer is less than 2%. The conductive ceramic layer with lower porosity reduces the loss of ECG signals during transmission. Thus, the stability of the ECG signal is improved.

In other embodiments of the present application, the conductive ceramic layer has a porosity of less than 0.5%. In the same way, a conductive ceramic layer with lower porosity can further improve the stability of the ECG signal.

Furthermore, in some embodiments of the present application, the difference between the electrochemical potential of the conductive ceramic layer and the electrochemical potential of the conductive layer is less than 0.3v. Therefore, the electrochemical potential of the conductive ceramic layer is close to that of the conductive layer, and it is difficult for the conductive ceramic layer and the conductive layer to undergo a galvanic reaction, further making the conductive layer less prone to electrochemical corrosion. Therefore, the ECG electrodes are not prone to discoloration.

Due to the mismatch in thermal expansion coefficient and/or modulus between the conductive ceramic layer and the conductive layer, it is easy to accumulate large stress in the conductive layer during the deposition and cooling process, resulting in cracking or poor adhesion of the conductive layer. Therefore, in some possible embodiments of the present application, the ECG electrode further includes a conductive connection layer, and the conductive connection layer is disposed between the conductive layer and the conductive ceramic layer. The conductive layer is electrically connected to the conductive ceramic layer through the conductive connection layer. The thermal expansion coefficient of the conductive connection layer is between the thermal expansion coefficient of the conductive layer and the thermal expansion coefficient of the conductive ceramic layer. The modulus of the conductive connection layer is between the modulus of the conductive layer and the modulus of the conductive ceramic layer. Therefore, when the conductive connection layer and the conductive layer are made by physical vapor deposition, the conductive connection layer can be used as a buffer layer during the deposition and cooling process to reduce the accumulation of large stress in the conductive layer. Therefore, the bonding force between the conductive layer and the conductive ceramic layer can be improved. Based on the above parameter selection requirements, in some embodiments, the material of the conductive connection layer is chromium or titanium.

In some embodiments of the present application, the ECG electrode further includes a transitional conductive connection layer, and the transitional conductive connection layer is disposed between the conductive connection layer and the conductive layer. The conductive layer is electrically connected to the conductive ceramic layer through the conductive connection layer and the transition conductive connection layer. The thermal expansion coefficient of the transition conductive connection layer is between the thermal expansion coefficient of the conductive connection layer and the thermal expansion coefficient of the conductive layer. The modulus of the transitional conductive connection layer is between the modulus of the conductive connection layer and the modulus of the conductive layer. In the same way, the transitional conductive connection layer can also serve as a buffer layer during the deposition and cooling processes to further reduce the accumulation of large stress in the conductive layer. Therefore, the bonding force between the conductive layer and the conductive ceramic layer can be further improved. Moreover, in some embodiments, the material of the transition conductive connection layer is a chromium-titanium mixture or a chromium-carbon mixture.

In some embodiments, the above-mentioned conductive connection layer, transition conductive connection layer and conductive layer are all formed using a physical vapor deposition process. The conductive connection layer, the transition conductive connection layer and the conductive layer are formed uniformly and densely, and have strong connection with the conductive ceramic layer. The process flow is simple and does not require complex fixtures.

In a second aspect, embodiments of the present application provide an electronic device, which includes a fixed structure and the ECG electrode described in the above embodiment. ECG electrodes can be mounted on fixed structures. Since the ECG electrodes in the electronic equipment of the embodiments of the present application have the same structure as the ECG electrodes described in the above embodiments, they can solve the same technical problems and achieve the same technical effects, which will not be described again here.

Description of drawings

Figure 1 is a schematic three-dimensional structural diagram of an electronic device that is a smart watch according to an embodiment of the present application;

Figure 2 is a schematic diagram of the module connection of each component in the smart watch according to the embodiment of the present application;

Figure 3 is a second schematic three-dimensional structural diagram of the electronic device being a smart watch according to the embodiment of the present application;

Figure 4 is a schematic structural diagram of the connection between the processor and the ECG electrodes in the smart watch according to the embodiment of the present application;

Figure 5 is a schematic structural diagram of an ECG electrode and an arm in an electronic device;

Figure 6 is an enlarged view of part A in Figure 5;

Figure 7 is a schematic structural diagram of the ECG electrodes and wires in the electronic device according to the embodiment of the present application;

Figure 8 is a schematic structural diagram of an ECG electrode in another electronic device;

Figure 9 is a schematic diagram showing the thickness of the conductive layer in the ECG electrode in the electronic device according to the embodiment of the present application;

Figure 10 is a schematic structural diagram of an ECG electrode with a conductive connection layer in the electronic device according to the embodiment of the present application;

Figure 11 is a schematic structural diagram of an ECG electrode having a conductive connection layer and a buffer conductive connection layer in the electronic device according to the embodiment of the present application;

Figure 12 (a), (b), (c), and (d) are respectively structural schematic diagrams of each process step of preparing the ECG electrode in the electronic device according to the embodiment of the present application;

Figure 13 is a schematic structural diagram of an embodiment of the present application in which the electronic device is smart glasses and the ECG electrodes are installed on the temples;

Figure 14 is a schematic structural diagram of an embodiment of the present application in which the electronic device is smart glasses and the ECG electrodes are installed on the nose bridge;

Figure 15 is a schematic structural diagram of an embodiment of the present application in which the electronic device is a smartphone and the ECG electrodes are integrated on the main control keys of the smartphone;

FIG. 16 is a partial cross-sectional view of the ECG electrode of Example 1 taken with a scanning electron microscope.

Reference number:
1000-electronic equipment, 100-strap, 200-watch body, 10-casing, 20-processor, 30-memory, 40-communication module, 50-
Charging module, 60-display, 70, 70a, 70b-ECG electrodes, 80-wire, 1-conductive ceramic layer, 1a-first surface, 1b-second surface, 11-matrix phase, 12-conductive phase, 13-sintering aid, 2-conductive layer, 3-conductive connection layer, 4-transition conductive connection layer, 101-temple legs, 102-nose bridge, 103-main control key, 01-insulation support block, 02-ring conductive layer.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be described in further detail below in conjunction with the accompanying drawings.

Hereinafter, the terms “first”, “second”, etc. are used for descriptive purposes only and shall not be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Thus, features defined by "first," "second," etc. may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise stated, "plurality" means two or more.

In addition, in this application, directional terms such as "upper", "lower", "left", "right", "horizontal" and "vertical" are defined relative to the schematically placed orientations of the components in the drawings. It should be understood that these directional terms are relative concepts and are used for relative description and clarification, which may change accordingly according to changes in the orientation of components in the drawings.

In this application, unless otherwise expressly stated and limited, the term "connection" should be understood in a broad sense. For example, "connection" may refer to a mechanical structure or a physical structure connection. For example, they can be fixedly connected, detachably connected, or integrated; they can be directly connected or indirectly connected through an intermediate medium. It can also be understood as the physical contact and electrical conduction of components, and it can also be understood as the connection between different components in the circuit structure through physical lines that can transmit electrical signals such as PCB copper foil or wires.

An embodiment of the present application provides an electronic device, which includes various smart devices that can be in direct contact with the skin. For example, the electronic devices include smart watches, smart bracelets, smart glasses, smart helmets, smart headbands, smart clothing, smart schoolbags, smart crutches, smart accessories and other wearable smart devices, as well as mobile phones, tablets, etc. personal computer), laptop computer (laptop computer), personal digital assistant (PDA), smart speakers, smart desk lamps, smart TVs, smart refrigerators and other devices that users can touch their shells, as well as electrocardiographs and electrocardiograms Monitors and other equipment with ECG detection functions. The embodiments of the present application do not place special restrictions on the specific forms of the above-mentioned electronic devices. For convenience of explanation, the following takes the electronic device as a smart watch as shown in Figure 1 as an example.

Please refer to FIG. 1 , which is a perspective view of an electronic device provided by some embodiments of the present application. As can be seen from the above, in this embodiment, the electronic device 1000 is a smart watch. The electronic device 1000 may include a watch band 100 and a watch body 200 connected to the watch band 100 . The watch band 100 is connected to both ends of the watch body 200 and is used to be fixed on the wrist of a human body. The watch body 200 includes a housing 10. The housing 10 is provided with a first opening and a second opening. The first opening and the second opening are arranged oppositely. Moreover, the first opening is far away from the human body, and the second opening is close to the human body. An accommodating cavity located between the first opening and the second opening is formed in the housing 10 . The accommodating cavity is connected to both the first opening and the second opening.

As shown in FIG. 2 , the electronic device 1000 may also include components such as a processor 20 , a memory 30 , a communication module 40 , a charging module 50 , and a display screen 60 . The processor 20 is electrically connected to the memory 30 , the communication module 40 , the charging module 50 and the display screen 60 . The above-mentioned processor 20 , memory 30 , communication module 40 , and charging module 50 are all arranged in the accommodation cavity of the housing 10 . The display screen 60 is installed at the first opening on the housing 10 .

The communication module 40 is used to implement WLAN (such as Wi-Fi network), Bluetooth (BR/EDR, BLE), global navigation satellite system (global navigation satellite system, GNSS), FM radio (frequency modulation, FM), etc. on the smart watch. Function. Processor 20 may parse signals received by communication module 40. The memory 30 is used to store various operating systems, software programs, and/or multiple sets of instructions, etc. The above-mentioned charging module 50 is used to provide electric energy to all electronic devices in the smart watch. Display 60 is used to display images or information.

Moreover, for a smart watch with an electrocardiogram detection function, as shown in FIG. 3 , the electronic device 1000 also includes an electrocardiogram electrode 70 and a wire 80 . The electrocardiogram electrode 70 can be installed at the second opening of the housing 10 . Therefore, the ECG electrode 70 can be in contact with human skin. The ECG electrodes 70 can also be integrated on the control buttons on the side of the housing 10 . May come into contact with skin when used to operate control buttons. The ECG electrode 70 is electrically connected to the processor 20 , and the processor 20 can also process the ECG data collected by the ECG electrode 70 . For example, as shown in FIG. 4 , the ECG electrodes 70 are electrically connected to the processor 20 through wires 80 . When the electronic device 1000 performs the electrocardiogram detection function, the electrocardiogram electrode 70 collects data on the user's electrocardiogram changes, and transmits the data to the processor 20 through the wire 80 for processing. Afterwards, the electrocardiogram processed by the processor 20 is displayed on the display screen 60 . Moreover, the display screen 60 displays the result obtained after processing by the processor 20 rate value.

It should be noted that if the above-mentioned ECG electrode 70 is directly made of conductive ceramics, the ECG electrode 70 made of conductive ceramics has the advantages of high voltage resistance, radiation resistance, high temperature resistance, etc. As shown in FIGS. 5 and 6 , the conductive ceramic includes a matrix phase 11 and a conductive phase 12 . The matrix phase 11 is an insulating material. The matrix phase 11 can enable the ECG electrode 70a to have good sintering performance and mechanical properties. The conductive phase 12 is dispersed in the matrix phase 11 in a network shape, and multiple conductive paths are formed to provide conductive performance.

Since the stability of the ECG signal quality is directly related to the effective contact area between the human body and the electrodes, the larger the effective contact area, the more stable the ECG signal quality. In the electrocardiographic electrode 70a directly made of conductive ceramic material, effective contact can be formed only when the conductive phase 12 in the conductive ceramic layer 1 comes into contact with human skin. The ECG electrode 70a is formed by a mixture of the matrix phase 11 and the conductive phase 12. Therefore, only part of the surface of the ECG electrode 70a in contact with human skin (ie, the upper surface of the ECG electrode 70a shown in Figure 4) has the conductive phase 12. , so that the effective contact area of the electrocardiographic electrode 70a made of conductive ceramic material is smaller, and the signal quality stability is lower.

In order to solve the above problem, referring to FIG. 7 , the ECG electrode 70 according to the embodiment of the present application includes a conductive ceramic layer 1 and a conductive layer 2 . The conductive ceramic layer 1 has opposing first and second surfaces 1a and 1b. The first surface 1 a of the conductive ceramic layer 1 is connected to the wire 80 . The conductive layer 2 is stacked on the second surface 1 b of the conductive ceramic layer 1 and is electrically connected to the conductive ceramic layer 1 . The outer surface of the conductive layer 2 away from the conductive ceramic layer 1 is used to contact the skin to collect electrical signals. Specifically, the electrical signal may be an electromyographic signal of a human body or other living things.

Therefore, compared with the ECG electrode 70a shown in FIG. 5 above, the ECG electrode 70 in the embodiment of the present application has a conductive layer 2 added to the conductive ceramic layer 1. The outer surface of the conductive layer 2 away from the conductive ceramic layer 1 can be All are in contact with the skin to form effective contact over the entire surface, so the effective contact area between the ECG electrode 70 and the skin is increased. Furthermore, the signal quality stability of the electrocardiographic electrode 70 is improved.

Furthermore, the electrocardiographic electrode 70b shown in FIG. 8 is embedded in the housing 10 described above. The ECG electrode 70b includes an insulating support block 01 (for example, made of sapphire or glass), and an annular conductive layer 02 wrapped around the outer wall of the insulating support block 01 (from the inside of the housing 10 to the outside of the housing 10). When using physical vapor deposition (PVD) to make the annular conductive layer 02, the insulating support block 01 needs to be rotated so that conductive materials can be deposited on multiple surfaces of the insulating support block 01. Therefore, the requirements for the fixture for fixing the insulating support block 01 are very high. At the same time, it takes a long time to make the annular conductive layer 02, and the surface area of the insulating support block 01 is small (such as the insulating support block 01 is opposite to the shell 10 The surface 011) is prone to the problem of incomplete coverage of conductive materials. Furthermore, if multiple ECG electrodes 70b shown in FIG. 8 are manufactured at the same time, the multiple insulating support blocks 01 may easily interfere or collide with each other while rotating in the reaction chamber of the physical vapor deposition equipment. Therefore, compared with the ECG electrode 70b shown in FIG. 8, the ECG electrode 70 in the embodiment of the present application only needs to form the conductive layer 2 on one outer surface of the conductive ceramic layer 1, that is, the second surface 1b, and the process flow is simple. , the production of the conductive layer 2 takes less time, does not require complex fixtures, and does not cause interference or collision with each other in the reaction chamber of the physical vapor deposition equipment when multiple ECG electrodes 70 shown in Figure 9 are produced simultaneously. question.

It should be noted that if the conductive layer 2 is made of pure metal material, it will be difficult to achieve a stable polarization potential. Moreover, the conductive layer 2 is prone to form a galvanic cell with the conductive ceramic layer 1, and electrochemical corrosion occurs, seriously affecting the appearance and ECG measurement function of the ECG electrode 70, and reducing the service life of the ECG electrode 70. Therefore, the material for making the conductive layer 2 in the embodiment of the present application is any one of nitride, carbide, and carbonitride of metal materials. For example, the material of the conductive layer 2 is any one of TiC, TiN, TiCN, CrC, CrN, CrCN, TiNbN, and TiNbC. These materials have the advantages of stable polarization potential, corrosion resistance and wear resistance. Thus, the above problems can be avoided.

Furthermore, the content of non-metallic elements and the content of metallic elements in the conductive layer 2 are different, and the polarization potential of the conductive layer 2 is also different. In some embodiments of the present application, the ratio of the content of non-metal elements to the content of metal elements in the conductive layer 2 is greater than 1:9. For example, the ratio of the content of non-metal elements to the content of metal elements in the conductive layer 2 is 1:8. , 1:6, 1:4 or 1:2. A higher content of non-metallic elements can make the conductive layer 2 have a stable polarization potential. Therefore, the conductive layer 2 is less likely to chemically react with sweat, and the ECG electrode 70 has better resistance to acid and alkali sweat corrosion.

Based on the above, in other embodiments of the present application, the ratio of the content of non-metal elements to the content of metal elements in the conductive layer 2 is greater than 1:4, such as the ratio of the content of non-metal elements to the content of metal elements in the conductive layer 2 be 1:3, 1:2 or 1:1. A higher content of non-metallic elements can make the conductive layer 2 have a more stable polarization potential and be less likely to chemically react with sweat. The ECG electrode 70 has better resistance to acid and alkali sweat corrosion.

In addition, in addition to the above-mentioned content of non-metallic elements in the conductive layer 2 that affects the acid-base sweat corrosion characteristics of the ECG electrode 70, some embodiments of the present application add silicon elements to the material of the conductive layer 2. For example, the material of the conductive layer 2 is any one of CrSiN, CrSiC, TiSiN, TiSiC, CrSiCN, and TiSiCN. Silicon element can also further improve the corrosion resistance of acid, alkali and sweat in the conductive layer 2 .

Furthermore, in order to ensure that the conductive layer 2 can have the above-mentioned stable polarization potential and is not prone to chemical reactions with sweat, the thickness of the conductive layer 2 cannot be too small. Therefore, in some embodiments of the present application, as shown in FIG. 9 , the thickness T ₁ of the conductive layer 2 is greater than or equal to At 0.4 μm, for example, the thickness T ₁ of the conductive layer 2 is 0.5 μm, 0.6 μm, 0.7 μm or 0.8 μm. Only a conductive layer 2 of sufficient thickness can ensure the performance of having the above-mentioned stable polarization potential and not easily reacting chemically with sweat.

The above mainly describes the various physical parameters that are required for designing the conductive layer 2 . The material and various physical parameters of the conductive ceramic layer 1 also need to be designed to ensure that the ECG electrode 70 has good performance.

The matrix phase 11 of the conductive ceramic layer 1 in the ECG electrode 70 in the embodiment of the present application can be made of materials such as zirconium oxide, silicon carbide, etc., so that it has good mechanical strength, sinterability, corrosion resistance, etc. The conductive phase 12 of the conductive ceramic layer 1 can be nitride, carbide, or carbonitride of transition metal. For example, the conductive phase 12 can be made of materials such as titanium carbide and titanium nitride. The resistivity of titanium carbide and titanium nitride is both less than 10 ^-5 Ω·m, so the overall resistivity of the conductive ceramic layer 1 made of the above two materials can be less than 10 ^-4 Ω·m. The smaller overall resistivity allows the ECG signal to have less resistance when passing through the conductive ceramic layer 1, thereby facilitating the transmission of the ECG signal. Moreover, the content of the conductive phase 12 in the conductive ceramic layer 1 should be greater than the percolation threshold to ensure that the conductive phases 12 can be connected to each other in the matrix phase 11 and form a conductive network.

It should be noted that in some embodiments of the present application, the conductive ceramic layer 1 may also contain a small amount of sintering aid. The sintering aid is used to improve the wetting of the matrix phase 11 and the conductive phase 12 and enhance the bonding force between different components. For example, the content of the sintering aid in the conductive ceramic layer 1 is less than or equal to 10% (weight percent) of the total content of the conductive ceramic layer 1 . The content of the sintering aid is small and has little impact on the structure of the conductive ceramic layer 1 .

In addition, since the conductive ceramic layer 1 cannot ensure perfect contact with all raw material powders during the sintering process, pores may appear in some areas. The electrons that transmit ECG signals will be scattered more and generate noise when passing through the pores in the conductive ceramic layer 1, which is not conducive to accurate transmission of ECG signals. Therefore, in some embodiments of the present application, the porosity of the conductive ceramic layer 1 is less than 2%, for example, the porosity of the conductive ceramic layer 1 is 0.5%, 1%, 1.5% or 1.8%. There are fewer pores in the conductive ceramic layer 1, which reduces the loss of ECG signals during transmission. Therefore, the impact of the pores on the accuracy of ECG signal transmission is reduced, and the stability of the ECG signal quality is higher.

Based on the above, in other embodiments of the present application, the porosity of the conductive ceramic layer 1 is less than 0.5%, for example, the porosity of the conductive ceramic layer 1 is 0.1%, 0.3% or 0.4%. There are very few pores in the conductive ceramic layer 1, which further reduces the impact of pores on the accuracy of ECG signal transmission and ensures high stability of ECG signal quality.

In addition, the difference between the electrochemical potential of the conductive ceramic layer 1 and the electrochemical potential of the conductive layer 2 will also affect the corrosion resistance of the ECG electrode 70 . When the difference between the electrochemical potential of the conductive ceramic layer 1 and the electrochemical potential of the conductive layer 2 is large, the conductive ceramic layer 1 and the conductive layer 2 easily form a primary battery and cause electrochemical corrosion. When the difference between the electrochemical potential of the conductive ceramic layer 1 and the electrochemical potential of the conductive layer 2 is small, the galvanic reaction between the conductive ceramic layer 1 and the conductive layer 2 is less likely to occur, so electrochemical corrosion is less likely to occur. Therefore, in some embodiments of the present application, the difference between the electrochemical potential of the conductive ceramic layer 1 and the electrochemical potential of the conductive layer 2 is less than 0.3v, such as the electrochemical potential of the conductive ceramic layer 1 and the electrochemical potential of the conductive layer 2 The difference in potential is 0.1v or 0.2v. The electrochemical potential of the conductive ceramic layer 1 is close to the electrochemical potential of the conductive layer 2, which can further make the conductive layer 2 less prone to electrochemical corrosion. Therefore, the ECG electrode 70 is less prone to discoloration.

Based on the above-mentioned materials and physical parameters of the conductive ceramic layer 1 and the materials and physical parameters of the conductive layer 2, there may also be a thermal expansion coefficient mismatch and/or a modulus mismatch between the conductive ceramic layer 1 and the conductive layer 2. Therefore, when the physical vapor deposition process is used to make the conductive layer 2 on the conductive ceramic layer 1, it is easy to accumulate large stress in the conductive layer 2 during the deposition and cooling process, resulting in cracking or poor adhesion of the conductive layer 2. question.

In order to reduce the above problems, in some embodiments of the present application, the above-mentioned ECG electrode 70 also includes a conductive connection layer 3 as shown in FIG. 10 , which is disposed between the conductive layer 2 and the conductive ceramic layer 1 . The conductive layer 2 is electrically connected to the conductive ceramic layer 1 through the conductive connection layer 3 . At this time, the conductive layer 2 and the conductive ceramic layer 1 are indirectly electrically connected. Furthermore, the thermal expansion coefficient of the conductive connection layer 3 is between the thermal expansion coefficient of the conductive layer 2 and the thermal expansion coefficient of the conductive ceramic layer 1 . The modulus of the conductive connection layer 3 is between the modulus of the conductive layer 2 and the modulus of the conductive ceramic layer 1 . In other words, along the direction away from the second surface 1 b of the conductive ceramic layer 1 , the thermal expansion coefficient of the coating layer including the conductive connection layer 3 and the conductive layer 2 gradually increases or decreases, and the modulus of the coating layer gradually increases or decreases. Small, so that the deformation amount of the conductive connection layer 3 under the influence of temperature change is between the deformation amount of the conductive layer 2 and the deformation amount of the conductive ceramic layer 1. Therefore, during the deposition and cooling process of making the coating layer, the conductive connection layer 3 can serve as a buffer layer, improving the bonding force between the conductive layer 2 and the conductive ceramic layer 1, and reducing the possibility of cracking or poor adhesion of the conductive layer 2. question.

For example, the material of the conductive connection layer 3 may be chromium or titanium. The conductive connection layer 3 has the same elements as some elements in the conductive layer 2 and some elements in the conductive ceramic layer 1. Therefore, the thermal expansion coefficient and modulus of the conductive layer 2 are the same as those of the conductive layer 2 or the conductive ceramic layer. The thermal expansion coefficient and modulus of 1 are relatively close.

In addition, in other embodiments of the present application, in addition to the above-mentioned conductive connection layer 3, the ECG electrode 70 also includes A transitional conductive connection layer 4 is provided between the conductive connection layer 3 and the conductive layer 2 . The conductive layer 2 is electrically connected to the conductive ceramic layer 1 through the conductive connection layer 3 and the transition conductive connection layer 4 . At this time, the conductive layer 2 and the conductive ceramic layer 1 are also indirectly electrically connected. The thermal expansion coefficient of the transitional conductive connection layer 4 is between the thermal expansion coefficient of the conductive connection layer 3 and the thermal expansion coefficient of the conductive layer 2 . The modulus of the transitional conductive connection layer 4 is between the modulus of the conductive connection layer 3 and the modulus of the conductive layer 2 . In the same way, along the direction away from the second surface 1b of the conductive ceramic layer 1, the thermal expansion coefficient of the coating layer including the conductive connection layer 3, the transition conductive connection layer 4 and the conductive layer 2 gradually increases or decreases, and the conductive connection layer 3, The modulus of the transition conductive connection layer 4 and the conductive layer 2 gradually increases or decreases, so that the deformation amount of the transition conductive connection layer 4 under the influence of temperature change is between the deformation amount of the conductive connection layer 3 and the deformation amount of the conductive layer 2 between. Therefore, during the deposition and cooling process of the coating layer, the conductive connection layer 3 and the transition conductive connection layer 4 can simultaneously serve as buffer layers, which can further avoid the problem of cracking in the conductive layer 2 .

It should be noted that the above-mentioned transition conductive connection layer 4 may be one layer or multiple layers, which is not limited in the embodiments of the present application. If the ECG electrode 70 includes a layer of transitional conductive connection layer 4, and the material of the conductive connection layer 3 is chromium or titanium, the material of the conductive layer 2 is any one of TiC, TiN, TiCN, CrC, CrN, CrCN, TiNbN, and TiNbC. One, the material of the transition conductive connection layer 4 is a chromium-titanium mixture or a chromium-carbon mixture. Thus, the thermal expansion coefficient and modulus of the transitional conductive connection layer 4 may be between the thermal expansion coefficient and modulus of the conductive connection layer 3 and the thermal expansion coefficient and modulus of the conductive layer 2 . If the transition conductive connection layer 4 is multi-layered, the material composition of the multi-layer transition conductive connection layer 4 can slowly transition from a material composition close to the conductive connection layer 3 to a material composition close to the conductive layer 2, so that the multi-layer transition The thermal expansion coefficient and modulus of the conductive connection layer 4 gradually increase or decrease from the thermal expansion coefficient and modulus of the conductive connection layer 3 to close to the thermal expansion coefficient and modulus of the conductive layer 2 .

It should be noted that the above-mentioned conductive connection layer 3, transition conductive connection layer 4 and conductive layer 2 can all be formed using a physical vapor deposition process. The formed conductive connection layer 3, transitional conductive connection layer 4 and conductive layer 2 are uniform and dense in film formation, have strong connection force with the conductive ceramic layer 1, the process flow is simple, and no complicated fixtures are required.

Moreover, the resistance in the transmission path of the ECG signal needs to be within a suitable range to ensure the smooth transmission of the ECG signal. Therefore, the thickness of the conductive connection layer 3 and the thickness of the transition conductive connection layer 4 need to be reasonably designed so that the resistance of the coating layer including the conductive connection layer 3, the transition conductive connection layer 4 and the conductive layer 2 along the thickness direction is less than 10 kΩ. Therefore, in some embodiments of the present application, the thickness T of the coating layer ranges from 0.8 to 2.5 μm. For example, the thickness T of the coating layer is 0.8 μm, 1.4 μm, 1.8 μm or 2.5 μm, so that the coating layer can The resistance in the thickness direction is less than 10kΩ.

Moreover, in other embodiments of the present application, the thickness T of the coating layer ranges from 1.0 μm to 1.5 μm. For example, the thickness T of the coating layer is 1.0 μm, 1.2 μm, 1.4 μm or 1.5 μm. In the same way, it can be further Reduce the resistance of the coating layer along the thickness direction.

Based on the structure of the above-mentioned ECG electrode 70, as shown in FIG. 12, the ECG electrode 70 can be prepared by the following process method. The process includes the following steps:

S100: Prepare conductive ceramic layer 1.

For example, as shown in (a) of FIG. 12 , the conductive ceramic layer 1 can be produced using processes such as discharge plasma sintering, hot press sintering, and normal pressure sintering. After that, the second surface 1b of the conductive ceramic layer 1 is processed. For example, grinding, grinding, etc. are used to change the surface flatness of the second surface 1b of the conductive ceramic layer 1, and sandblasting, drawing, polishing, laser, etc. are used to create a surface texture on the second surface 1b of the conductive ceramic layer 1. , to facilitate the deposition of subsequent coating layers (such as conductive layer 2).

S200: Form the conductive connection layer 3, the transition conductive connection layer 4 and the conductive layer 2 on the second surface 1b of the conductive ceramic layer 1 in order from top to bottom.

For example, as shown in (b), (c) and (d) in Figure 12, a physical vapor deposition process is used to sequentially form the conductive connection layer 3, the transition conductive connection layer 4 and the second surface 1b of the conductive ceramic layer 1. Conductive layer 2.

The ECG electrodes 70 in the above embodiments are all explained by taking the example of being installed on a smart watch. It should be noted that when the ECG electrode 70 is applied to other electronic devices 1000, the ECG electrode 70 needs to be installed at a position where the electronic device 1000 can come into contact with the skin. For example, as shown in Figure 13, the electronic device 1000 is smart glasses. The ECG electrode 70 is installed on the inner wall of the temple 101 of the smart glasses at a position that can contact the skin of the human face. Therefore, the fixed structure of the ECG electrode 70 is the temple 101 . Alternatively, as shown in FIG. 14 , the ECG electrode 70 is installed on the nose bridge 102 of the frame in the smart glasses. Therefore, the fixed structure of the ECG electrode 70 is the nose bridge 102 housing.

For example, as shown in FIG. 15 , the electronic device 1000 is a smartphone, and the ECG electrode 70 can be directly integrated with the main control keys 103 (such as fingerprint recognition buttons and volume keys) of the smartphone. Therefore, the fixed structure of the ECG electrode 70 is the housing of the main control button 103 . When the user performs fingerprint recognition or operates buttons, the user's ECG signal can be detected. Similarly, if the electronic device 1000 is a tablet computer, the ECG electrodes 70 can be directly integrated with the central control button of the tablet computer. Similarly, when the user performs fingerprint recognition or operates buttons, Complete the detection of the user's ECG signal.

The above-mentioned electrocardiographic electrode 70 will be described in detail below with reference to specific embodiments. The electrocardiographic electrode 70 in the following embodiments includes a conductive ceramic layer 1, a conductive connection layer 3, a transitional conductive connection layer 4 and a conductive layer 2 that are stacked in sequence. The first surface 1 a of the conductive ceramic layer 1 away from the conductive connection layer 3 is connected to the wire 80 . The conductive ceramic layer 1 is electrically connected to the conductive layer 2 through the conductive connection layer 3 and the transition conductive connection layer 4 .

Example 1

The conductive ceramic layer 1 in the electrocardiographic electrode 70 of this example includes a matrix phase 11, a conductive phase 12, and a sintering aid 13 as shown in FIG. 16 . The material of the matrix phase 11 is silicon carbide, and the content of the matrix phase 11 in the conductive ceramic layer 1 is 44.4%. The material of the conductive phase 12 is titanium carbide, and the content of the conductive phase 12 in the conductive ceramic layer 1 is 45.6%. The sintering aid 13 is a mixture of aluminum oxide and yttrium oxide. The content of aluminum oxide in the conductive ceramic layer 1 is 4.3%. The content of yttrium oxide in the conductive ceramic layer 1 is 5.7%. The above content percentages are all weight percentages. The thickness of the conductive ceramic layer 1 is 1.2mm.

The material of the above-mentioned conductive connection layer 3 is chromium, the material of the transition conductive connection layer 4 is a chromium-titanium mixture, and the conductive layer 2 is titanium nitride. The content ratio of titanium element and nitrogen element in the conductive layer 2 is 1.5:1. The thickness of the conductive connection layer 3 is 0.1 μm, the thickness of the transition conductive connection layer 4 is 1.4 μm, and the thickness of the conductive layer 2 is 0.5 μm. Therefore, the total thickness of the conductive connection layer 3, the transition conductive connection layer 4 and the conductive layer 2 is 2.0 μm.

The ECG electrode 70 with the above parameters can be produced using the following steps:

S101: Prepare conductive ceramic layer 1.

For example, the conductive ceramic layer 1 is prepared in the order of mixing, forming, drying, and sintering. Preparing the conductive ceramic layer 1 specifically includes the following steps:

S1011: Mix materials such that the weight percentage of silicon carbide is 44.4%, the weight percentage of titanium carbide is 45.6%, the weight percentage of aluminum oxide is 4.3%, and the weight percentage of yttrium oxide is 5.7%, to obtain mixed powder. Then add polyvinyl alcohol with a weight of 8% of the total weight of the mixed powder as a binder into the mixed powder.

S1012: Press the mixture containing the binder into the mold at a pressure of 150MPa for shaping.

S1013: Demold the formed body in the mold. After demoulding, the green body was dried in an environment with a temperature of 80°C for 10 hours to obtain a green body.

S1014: Put the blank into the vacuum sintering furnace. After that, the temperature in the furnace cavity of the vacuum sintering furnace was raised to 1850°C and maintained at normal pressure, and the green body was sintered for 1 hour. Finally, the green body is naturally cooled to room temperature to obtain the conductive ceramic layer 1.

S1015: After performing grinding, rough polishing, fine polishing and other process steps on the second surface 1b of the conductive ceramic layer 1, the second surface 1b with a roughness of less than 0.2 μm is obtained.

S201: Perform process steps such as water washing, degreasing, and drying on the conductive ceramic layer 1. Afterwards, the conductive ceramic layer 1 is placed into the cavity of the physical vapor deposition equipment, and the second surface 1 b of the conductive ceramic layer 1 is cleaned with plasma for 10 minutes. After that, the conductive connection layer 3, the transition conductive connection layer 4 and the conductive layer 2 are sequentially plated on the second surface 1b of the conductive ceramic layer 1 using a physical vapor deposition process.

FIG. 16 is a partial cross-sectional view of the ECG electrode 70 produced through the above steps, taken using a scanning electron microscope. The porosity of the conductive ceramic layer 1 in the ECG electrode 70 is 0.28%, the resistivity of the conductive ceramic layer 1 is 1.7×10 ^-5 Ω·m, and the density of the conductive ceramic layer 1 is 3.8g/cm ³ . The flexural strength of 1 is 428MPa. Therefore, the conductive ceramic layer 1 has the advantages of lower density, higher bending strength, and excellent mechanical properties.

An electrocardiogram signal test was performed on the electrocardiogram electrode 70 produced in the above steps and the electrocardiogram electrode 70 with the conductive phase 12 made of titanium boride and the matrix phase 11 made of titanium carbide without coating. After testing, compared with the latter, the stability of the ECG signal curve obtained by the ECG electrode 70 in this example can be improved by 18%, which contributes to more accurate ECG diagnosis and reduces the possibility of misdiagnosis.

Furthermore, the acid-base sweat wrapping test was performed on the ECG electrode 70 produced in the above steps and the ECG electrode 70 with the conductive phase 12 made of titanium boride, the matrix phase 11 made of titanium carbide and without coating. Observing the test results after 120 hours, it was found that the ECG electrode 70 in this example did not discolor or corrode in both acidic sweat and alkaline sweat environments, while the latter's ECG electrode 70 turned yellow after the alkaline sweat test.

Example 2

In this example, the conductive ceramic layer 1 of the central electrical electrode 70 includes a matrix phase 11 and a conductive phase 12 . The material of the matrix phase 11 is zirconia, and the content of the matrix phase 11 in the conductive ceramic layer 1 is 44%. The material of the conductive phase 12 is titanium carbide, and the content of the conductive phase 12 in the conductive ceramic layer 1 is 56%. The above content percentages are all weight percentages. The thickness of the conductive ceramic layer 1 is 1.2mm.

The material of the above-mentioned conductive connection layer 3 is chromium, the material of the transition conductive connection layer 4 is a chromium-carbon mixture, and the conductive layer 2 is chromium carbide. guide The content ratio of chromium element and nitrogen element in the electric layer 2 is 4.6:1. The thickness of the conductive connection layer 3 is 0.1 μm, the thickness of the transition conductive connection layer 4 is 1 μm, and the thickness of the conductive layer 2 is 0.4 μm. Therefore, the total thickness of the conductive connection layer 3, the transition conductive connection layer 4 and the conductive layer 2 is 1.5 μm.

S102: Prepare conductive ceramic layer 1.

S1021: Mix the materials so that the weight percentage of zirconium oxide is 44% and the weight percentage of titanium carbide is 56% to obtain mixed powder. Then add polyvinyl alcohol with a weight of 10% of the total weight of the mixed powder as a binder into the mixed powder.

S1022: Press the mixture containing the binder into the mold at a pressure of 100MPa for shaping.

S1023: Demold the formed body in the mold. After demoulding, the green body was dried in an environment with a temperature of 80°C for 10 hours to obtain a green body. Afterwards, the blank was placed in an environment with a temperature of 700°C for 5 hours for degumming.

S1024: Put the blank after debinding into the vacuum sintering furnace. After that, the temperature in the furnace cavity of the vacuum sintering furnace was raised to 1750°C and maintained at normal pressure, and the green body was sintered for 2 hours. Finally, the green body is naturally cooled to room temperature to obtain the conductive ceramic layer 1.

S1025: After performing grinding, rough polishing, fine polishing and other process steps on the second surface 1b of the conductive ceramic layer 1, a second surface 1b with a roughness of 0.9 μm is obtained.

S202: Perform process steps such as water washing, degreasing, and drying on the conductive ceramic layer 1. Afterwards, the conductive ceramic layer 1 is placed into the cavity of the physical vapor deposition equipment, and the second surface 1 b of the conductive ceramic layer 1 is cleaned with plasma for 10 minutes. After that, the conductive connection layer 3, the transition conductive connection layer 4 and the conductive layer 2 are sequentially plated on the second surface 1b of the conductive ceramic layer 1 using a physical vapor deposition process.

In the ECG electrode 70 produced through the above process steps, the porosity of the conductive ceramic layer 1 is 0.5%, the resistivity of the conductive ceramic layer 1 is 8.0×10 ^-5 Ω·m, and the density of the conductive ceramic layer 1 is 5.6 g/cm ³ , the flexural strength of the conductive ceramic layer 1 is 592MPa. Therefore, the conductive ceramic layer 1 has properties such as lower density, higher bending strength, and excellent mechanical properties.

The ECG signal test was performed on the ECG electrode 70 produced in the above steps and the ECG electrode 70 with the conductive phase 12 made of titanium boride, the matrix phase 11 made of titanium carbide and without coating. Compared with the latter, the stability of the ECG signal curve obtained by the ECG electrode 70 in this example can be improved by 15%, which also contributes to more accurate ECG diagnosis and reduces the possibility of misdiagnosis.

In addition, comparing Example 1 and Example 2, the matrix phase 11 of the conductive ceramic layer 1 in Example 2 uses zirconia. Zirconia has higher bending strength and is suitable for scenarios where ECG electrodes have high requirements for bending strength. At the same time, zirconia is also denser. Example 1 and Example 2 also look different. In Example 1, the appearance color of the conductive layer 2 is gold, and the appearance texture of the conductive layer 2 is a polished surface. In Example 2, the appearance color of the conductive layer 2 is black, and the appearance texture of the conductive layer 2 is a sandblasted surface. Therefore, Example 1 and Example 2 can be respectively applied to application scenarios with different appearance design requirements.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application. should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

An electrocardiographic electrode, characterized by including:

A conductive ceramic layer, the conductive ceramic layer has an opposite first surface and a second surface; the first surface is used for electrical connection with a wire;

A conductive layer, the conductive layer is stacked on the second surface of the conductive ceramic layer and is electrically connected to the conductive ceramic layer; the conductive layer is used to contact the skin to collect electrical signals.
The electrocardiographic electrode according to claim 1, characterized in that the material of the conductive layer is any one of nitride, carbide and carbonitride of metal materials; wherein, the non-metal elements in the conductive layer The ratio of the content to the content of metal elements is greater than 1:9.
The electrocardiographic electrode according to claim 2, characterized in that the ratio of the content of non-metallic elements to the content of metallic elements in the conductive layer is greater than 1:4.
The electrocardiographic electrode according to any one of claims 1 to 3, characterized in that the material of the conductive layer is any one of TiC, TiN, TiCN, CrC, CrN, CrCN, TiNbN, and TiNbC.
The electrocardiographic electrode according to any one of claims 2 to 4, characterized in that the material of the conductive layer further includes silicon element.
The electrocardiographic electrode according to any one of claims 1 to 5, wherein the thickness of the conductive layer is greater than or equal to 0.4 μm.
The electrocardiographic electrode according to any one of claims 1 to 6, characterized in that the resistivity of the conductive ceramic layer is less than 10 -4 Ω·m.
The electrocardiographic electrode according to any one of claims 1 to 7, wherein the porosity of the conductive ceramic layer is less than 2%.
The electrocardiographic electrode according to any one of claims 1 to 8, wherein the porosity of the conductive ceramic layer is less than 0.5%.
The electrocardiographic electrode according to any one of claims 1 to 9, characterized in that the difference between the electrochemical potential of the conductive ceramic layer and the electrochemical potential of the conductive layer is less than 0.3v.
The ECG electrode according to any one of claims 1-10, characterized in that the ECG electrode further includes:

A conductive connection layer, the conductive connection layer is provided between the conductive layer and the conductive ceramic layer; the conductive layer is electrically connected to the conductive ceramic layer through the conductive connection layer; the thermal expansion of the conductive connection layer The coefficient is between the thermal expansion coefficient of the conductive layer and the thermal expansion coefficient of the conductive ceramic layer; the modulus of the conductive connection layer is between the modulus of the conductive layer and the modulus of the conductive ceramic layer.
The electrocardiographic electrode according to claim 11, wherein the conductive connection layer is made of chromium or titanium.
The ECG electrode according to claim 11 or 12, characterized in that the ECG electrode further includes:

A transitional conductive connection layer, the transitional conductive connection layer is provided between the conductive connection layer and the conductive layer; the conductive layer is electrically connected to the conductive ceramic layer through the conductive connection layer, the transition conductive connection layer; The thermal expansion coefficient of the transition conductive connection layer is between the thermal expansion coefficient of the conductive connection layer and the thermal expansion coefficient of the conductive layer; the modulus of the transition conductive connection layer is between the modulus of the conductive connection layer and the thermal expansion coefficient of the conductive connection layer. between the modulus of the conductive layer.
The electrocardiographic electrode according to claim 13, wherein the transition conductive connection layer is made of a chromium-titanium mixture or a chromium-carbon mixture.
The electrocardiographic electrode according to claim 13 or 14, wherein the conductive connection layer, the transition conductive connection layer and the conductive layer are all formed using a physical vapor deposition process.
An electronic device, characterized in that it includes a fixed structure and the ECG electrode according to any one of claims 1 to 15, and the ECG electrode is installed on the fixed structure.