Finger electrocardiosignal extraction device capable of reducing in-band noise

Abstract

The invention relates to the technical field of electrocardiosignal extraction, in particular to a finger electrocardiosignal extraction device capable of reducing in-band noise, which comprises a metal cavity, a flexible layer, an insulating layer and an electrode layer, the metal cavity is a cuboid cavity, the flexible layer is attached to the top wall and the side wall in the metal cavity, the insulating layer is attached to the bottom wall in the metal cavity, and the electrode layer is arranged in the metal cavity. The electrode layer is arranged on the insulating layer; during application, a finger extends into the metal cavity, and a finger pulp is in contact with the electrode layer. The metal chamber blocks external electromagnetic interference, and it is ensured that electrocardiosignals are collected more stably and purely; the flexible layer limits finger movement, and artifacts and noise caused by finger movement are reduced; the finger is limited in the metal chamber, the contact between the finger and the electrode is stable, the signal transmission is stable, and the in-band noise is also reduced. By integrating the effects, the method has a good application prospect in the technical field of finger electrocardiosignal extraction.

Description

Technical Field

[0001] The invention relates to the technical field of electrocardiogram signal extraction, and in particular to a finger electrocardiogram signal extraction device capable of reducing in-band noise. Background Art

[0002] The traditional way to collect ECG signals is to attach electrodes to multiple parts of the body, such as the chest and limbs, and then connect them to an ECG machine for signal collection. Common methods include 12 lead ECG. The traditional way to collect ECG signals requires correctly attaching multiple electrodes to designated locations on the body. The operation is complicated and requires professional knowledge, making it difficult for ordinary people to operate at home. In addition, traditional ECG equipment is usually large and inconvenient to carry and use daily.

[0003] The operation of collecting ECG signals through fingers is simple. You only need to place your fingers on the device to collect ECG signals. No professional knowledge is required, which is suitable for home and personal use. In addition, collecting ECG signals through fingers does not require electrodes to be attached to the body, which reduces skin irritation and discomfort. Of course, finger collection equipment is more portable, small in size, easy to carry, and can be used for ECG monitoring anytime and anywhere.

[0004] The frequency band of ECG signals is usually between 0.05Hz and 150Hz. Any noise within this frequency band will affect the quality and accuracy of ECG signals. Noise generated within the frequency band of ECG signals is called in-band noise. Since the fingers are far away from the heart, noise is easily introduced during the transmission of ECG signals to the fingers, affecting the quality of ECG signals.

[0005] For in-band noise, using only digital filtering to process it is easy to cause signal distortion. That is to say, while the digital filter removes the noise, it also distorts the effective components of the ECG signal. Especially when the frequency range is close, the filter cannot completely distinguish between the signal and the noise, thus affecting the accuracy of the ECG signal. In particular, such a filter is prone to losing the high-frequency detail information of the ECG signal. For example, when a low-pass filter is used to remove high-frequency noise, typical ECG characteristics such as the sharp edges and details of the QRS complex will be lost. Summary of the invention

[0006] To solve the above problems, the present invention provides a finger ECG signal extraction device for reducing in-band noise, including a metal chamber, a flexible layer, an insulating layer, and an electrode layer. The metal chamber is a rectangular cavity for accommodating a finger, the flexible layer is attached to the top wall and side walls of the metal chamber, the insulating layer is attached to the bottom wall of the metal chamber, and the electrode layer is placed on the insulating layer; when in use, the finger is inserted into the metal chamber and the fingertip contacts the electrode layer.

[0007] The in-band noise of ECG signals is caused by many factors, such as (1) electromagnetic interference: surrounding electronic devices (such as mobile phones, computers, etc.) generate electromagnetic interference, which will be superimposed on the ECG signals to form in-band noise; (2) motion artifacts: fingers are prone to slight movements during the acquisition process. These tiny movements generate artifacts, interfere with the stability of ECG signals, and increase in-band noise; (3) unstable contact resistance: the contact area between the finger and the electrode is small, and the resistance of the skin surface is unstable, which is easily affected by the contact surface condition, resulting in unstable signal transmission and thus generating noise.

[0008] In the present invention, the metal chamber shields external electromagnetic interference, and the metal material can effectively block external electromagnetic waves, preventing external electromagnetic waves from interfering with the collection of electrocardiogram signals, thereby reducing in-band noise; the flexible layer is attached to the top wall and side walls of the metal chamber, and can absorb the mechanical vibration generated when the finger contacts the metal chamber, reducing the noise caused by finger movement or environmental vibration, making the electrocardiogram signal more stable; in addition, the hollow metal chamber tightly confines the finger therein, so that the contact surface between the finger and the electrode is stable, the signal transmission is stable, and the in-band noise is also reduced.

[0009] Furthermore, the metal chamber is made of copper, aluminum or stainless steel, which have good electrical conductivity and shielding effectiveness, and can effectively block external electromagnetic waves and reduce the interference of external electromagnetic waves on ECG signals.

[0010] Furthermore, the material of the flexible layer is silicone or polyurethane. These materials are soft and have good vibration reduction performance, and can absorb the mechanical vibration generated when the finger contacts the metal chamber, thereby reducing motion artifacts.

[0011] Furthermore, the material of the insulating layer is polytetrafluoroethylene or polyimide. These materials have good insulation properties and can prevent electrical short circuits between the metal chamber and the electrode layer, thereby ensuring signal purity.

[0012] Furthermore, the material of the electrode layer is silver / silver chloride electrode. Silver / silver chloride electrode has good conductivity and biocompatibility, and can stably collect electrocardiogram signals.

[0013] Furthermore, the root of the metal chamber at least partially covers the proximal phalanx. Covering the proximal phalanx can effectively limit the movement of the finger during the acquisition process, thereby reducing artifacts and noise caused by finger movement. In addition, there is less muscle activity at the proximal phalanx, and by covering this part, the electromyographic signal interference caused by the extensor tendon activity on the back of the finger can be effectively reduced.

[0014] Furthermore, at the top wall of the metal chamber, the flexible layer is doped with a conductive microstructure. On the one hand, the conductive microstructure can form a continuous conductive path, enhance the shielding effect of the flexible layer, effectively block external electromagnetic interference from entering the metal chamber, and reduce the in-band noise in the ECG signal; on the other hand, the conductive microstructure forms a microscopic conductive network in the flexible layer, absorbs and scatters the high-frequency electromyographic signal generated by the finger muscle activity, and reduces its interference with the ECG signal.

[0015] Furthermore, the material of the conductive microstructure is silver, copper or nickel.

[0016] Furthermore, the conductive microstructure is linear. The linear conductive microstructure is more likely to form a continuous conductive network in the flexible layer, forming a uniformly distributed electric field, reducing local electric field concentration, and providing a more stable and efficient electromagnetic shielding effect; in addition, due to the high aspect ratio of the linear structure, the linear conductive microstructure can cover a larger area, forming a uniform and dense shielding layer, which can better block external electromagnetic interference and reduce the high-frequency noise generated internally. For electromyographic signals, the linear conductive microstructure also enhances the absorption and scattering of high-frequency noise, reduces local electric field concentration, and the conductive network formed helps to disperse and absorb the energy of electromyographic signals at the microscopic level, reducing the interference of electromyographic signals on electrocardiographic signals.

[0017] Furthermore, the line diameter of the conductive microstructure is 1 micrometer to 10 micrometers.

[0018] Beneficial effects of the present invention: (1) The metal chamber and its shielding design of the present invention effectively block external electromagnetic interference, ensure that the acquisition of ECG signals is more stable and pure, significantly reduce in-band noise, and improve the quality of ECG signals.

[0019] (2) The design of the flexible layer and the covering proximal phalanx of the present invention effectively restricts finger movement, reduces artifacts and noise caused by finger movement, and improves the stability of the ECG signal.

[0020] (3) In the present invention, the finger is confined in the metal chamber, the contact between the finger and the electrode is stable, the signal transmission is stable, and the in-band noise is reduced.

[0021] (4) The present invention dopes conductive microstructures into the flexible layer to form a continuous conductive network, which enhances the shielding effect and effectively reduces the interference of electromyographic signals, further improving the purity and reliability of electrocardiographic signals.

[0022] Based on the above beneficial effects, the present invention has good application prospects in the technical field of electrocardiogram signal extraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1A schematic diagram of a finger electrocardiogram signal extraction device for reducing in-band noise.

[0024] Figure 2 The present invention is a cross-sectional view of a finger electrocardiogram signal extraction device for reducing in-band noise.

[0025] In the figure: 1. Metal chamber; 2. Flexible layer; 3. Finger; 4. Insulation layer; 5. Electrode layer. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples.

[0027] The present invention provides a finger electrocardiogram signal extraction device for reducing in-band noise, such as Figure 1 and Figure 2 As shown, it includes a metal chamber 1, a flexible layer 2, an insulating layer 4, and an electrode layer 5. The metal chamber 1 is a rectangular cavity with an inner cavity length of 70-80 mm, a width and a height of 20-30 mm, and is used to accommodate a finger 3; the root (i.e., the end) of the metal chamber 1 at least partially covers the proximal phalanx. The selection of the material and thickness of the metal chamber 1 is based on the conductivity, strength, shielding effectiveness, and other aspects of the material: when the material of the metal chamber 1 is copper, aluminum, or stainless steel, the wall thickness of the metal chamber 1 is 0.3-1.5 mm. When the metal chamber 1 is made of copper, the wall thickness is 0.5-1 mm; when the metal chamber 1 is made of aluminum, the wall thickness is 1 mm-1.5 mm; when the metal chamber 1 is made of stainless steel, the wall thickness is 0.3-0.7 mm. The flexible layer 2 is attached to the top wall and side walls of the metal chamber 1, and the material of the flexible layer 2 is silicone or polyurethane, and the thickness is 1-2 mm. The insulating layer 4 is attached to the bottom wall of the metal chamber 1. The insulating layer 4 is made of polytetrafluoroethylene or polyimide with a thickness of 0.5-1 mm. The main functions of the insulating layer 4 are electrical isolation and signal protection. The electrode layer 5 is placed on the insulating layer 4. The electrode layer 5 is made of silver / silver chloride electrode. The area of ​​the electrode sheet is 10-15 square millimeters and the thickness is 0.1-0.2 mm.

[0028] The specific process of applying the finger ECG signal extraction device of the present invention includes: placing the finger ECG signal extraction device steadily on a stable surface, and then the user gently inserts the finger 3 that needs to collect the ECG signal into the metal chamber 1, wherein the finger pulp faces the electrode layer 5 side, and the finger 3 is completely inserted into the metal chamber 1 and contacts the electrode layer 5; the finger 3 is kept as still as possible to reduce the interference of motion artifacts and electromyographic signals. During the insertion of the finger 3, the flexible layer 2 in the metal chamber 1 fits the surface of the finger 3, provides stable support and absorbs tiny mechanical vibrations, thereby reducing the noise caused by the movement of the finger 3. The shielding effect of the metal chamber 1 will effectively block external electromagnetic interference and ensure the purity of the ECG signal. Through the electrode layer 5, the ECG signal is collected and transmitted to the signal processing unit, and the signal processing unit further processes the collected signal. During the whole process, the user needs to keep the finger 3 stable and still, avoid any unnecessary movement, and ensure the accuracy and reliability of signal acquisition. After completing the signal acquisition, the user can gently remove the finger from the metal chamber 1 and turn off the device.

[0029] In order to make the present invention adapt to different fingers 3, a controllable airbag is arranged between the flexible layer 2 and the metal chamber 1, and the controllable airbag is connected to a micro air pump. The micro air pump is used to inflate or deflate the controllable airbag, and can expand or contract according to the size and shape of the finger 3 to achieve the best fitting effect. The controllable airbag not only makes the present invention adapt to different fingers 3, but also provides soft and uniform pressure, reduces the pressure of the rigid structure on the finger 3, and improves the comfort of the user. Of course, the controllable airbag can also absorb and buffer the tiny vibrations of the finger 3 and external vibrations, reduce the interference of mechanical vibrations on the electrocardiogram signal, and further reduce the in-band noise.

[0030] In order to better reduce the noise interference caused by movement, a finger rest is provided in the metal chamber 1, and the size of the finger rest is smaller than the size of the bottom of the metal chamber 1. The finger rest is fixed to the bottom of the metal chamber 1 and connected by an adhesive. The finger rest is made of a flexible and moderately hard material, such as silicone. The insulating layer 4 covers the bottom of the metal chamber 1, including the area where the finger rest is located. The insulating layer 4 is fixed to the bottom of the metal chamber 1 and the surface of the finger rest by an adhesive. The electrode layer 5 is placed on the insulating layer 4, located on the top of the finger rest, so that the contact area between the electrode layer 5 and the finger 3 is maximized. Since the finger rest is designed as a groove or half-tube structure that matches the shape of the finger 3, it covers the proximal and middle phalanges of the finger and can provide full-length support, reducing noise interference caused by movement.

[0031] In addition, the finger ECG signal extraction device is designed in the form of a glove, and only the finger part for measuring ECG is retained, and the other finger covers are cut off, and an elastic band is set at the wrist end of the glove. The glove form plus the elastic band at the wrist end make the glove fit the hand tightly, prevent the individual finger covers from slipping off during use, and improve the stability of signal collection.

[0032] Based on the embodiment 1, a conductive microstructure is doped in the flexible layer 2 at the top wall of the metal chamber 1. The conductive microstructure is made of silver, copper or nickel, and is linear, with a diameter of 1 to 10 micrometers.

[0033] The extensor tendons on the back of the fingers are the main conduction path of the electromyographic signals. The flexible layer 2 on the top wall of the metal chamber 1 is doped with conductive microstructures to weaken these electromyographic signals. The electrocardiographic signals are mainly transmitted through the conductive medium of the human body, including blood, muscles, skin and other soft tissues. Doping the conductive microstructures in the above-mentioned flexible layer 2 will not significantly weaken the electrocardiographic signals of the fingers.

[0034] Currently, researchers have prepared silver microwires, copper microwires, and nickel microwires. The steps of doping the conductive microstructure in the flexible layer include: dispersing the prepared conductive microwires in a solvent to form a uniform dispersion; adding the dispersion to the solution of the flexible matrix material and stirring it thoroughly so that the conductive microwires are evenly distributed in the matrix material; coating the matrix material mixed with the conductive microwires on the top wall of the metal chamber 1 to form a uniform flexible layer 2; and finally curing at an appropriate temperature, so that the flexible layer 2 is formed and attached to the top wall of the metal chamber 1.

[0035] In the application, it is preferred to use distributed electrodes, which are designed as multiple small electrode sheets arranged in a grid or linear distribution on the finger 3. The size of each electrode sheet is 2 mm to 5 mm, ensuring that a larger area is covered. Distributed electrodes can cover a larger skin area, capture more ECG signals, and reduce signal loss and noise caused by poor contact of a single electrode. In addition, distributed electrodes collect signals through multiple contact points, which can smooth local resistance changes, improve signal stability, and reduce artifacts caused by finger micro-movements.

[0036] In addition, when used, the metal chamber 1 is grounded, and single-point grounding is used to reduce ground loop interference and ensure the purity and stability of the ECG signal. Use low-resistance wires, and the wires are as short as possible. Single-point connection to the single-point connection point of the analog ground and digital ground on the circuit board ensures a unified potential reference for the entire system, reduces the impact of noise and electromagnetic interference on the signal, and improves the integrity and accuracy of the ECG signal. In addition, low-resistance wires and the shortest possible wire length also reduce ground resistance and parasitic inductance, reduce the possibility of noise coupling, and ensure the stability of signal transmission.

[0037] In summary, the present invention provides a finger ECG signal extraction device that reduces in-band noise, including a metal chamber 1, a flexible layer 2, an insulating layer 4, and an electrode layer 5. The metal chamber 1 is a rectangular cavity, the flexible layer 2 is attached to the top wall and the side wall in the metal chamber 1, the insulating layer 4 is attached to the bottom wall in the metal chamber 1, and the electrode layer 5 is placed on the insulating layer 4; when used, the finger 3 is inserted into the metal chamber 1, and the fingertip contacts the electrode layer 5. The metal chamber 1 of the present invention blocks external electromagnetic interference, ensuring that the acquisition of ECG signals is more stable and pure; the flexible layer 2 limits the movement of the finger 3, reducing the artifacts and noise caused by the movement of the finger 3; the finger 3 is confined in the metal chamber 1, the contact between the finger 3 and the electrode is stable, the signal transmission is also stable, and the in-band noise is also reduced. Combining the above effects, the present invention has good application prospects in the field of finger ECG signal extraction technology.

[0038] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A finger electrocardiogram signal extraction device for reducing in-band noise, characterized in that: It includes a metal chamber, a flexible layer, an insulating layer, and an electrode layer. The metal chamber is a rectangular cavity for accommodating a finger. The flexible layer is attached to the top wall and side walls of the metal chamber, the insulating layer is attached to the bottom wall of the metal chamber, and the electrode layer is placed on the insulating layer. When in use, the finger is inserted into the metal chamber.

2. The finger electrocardiogram signal extraction device with reduced in-band noise as claimed in claim 1, characterized in that: The material of the metal chamber is copper, aluminum or stainless steel.

3. The finger electrocardiogram signal extraction device with reduced in-band noise as claimed in claim 1, characterized in that: The material of the flexible layer is silicone or polyurethane.

4. The finger electrocardiogram signal extraction device with reduced in-band noise as claimed in claim 1, characterized in that: The material of the insulating layer is polytetrafluoroethylene or polyimide.

5. The finger electrocardiogram signal extraction device with reduced in-band noise as claimed in claim 1, characterized in that: The material of the electrode layer is silver / silver chloride electrode.

6. The finger electrocardiogram signal extraction device with reduced in-band noise as claimed in claim 1, characterized in that: The root of the metal chamber at least partially covers the proximal phalanx.

7. The finger electrocardiogram signal extraction device with reduced in-band noise according to any one of claims 1 to 6, characterized in that: The flexible layer is doped with a conductive microstructure at the top wall of the metal cavity.

8. The finger electrocardiogram signal extraction device with reduced in-band noise as claimed in claim 7, characterized in that: The conductive microstructure is made of silver, copper or nickel.

9. The finger electrocardiogram signal extraction device with reduced in-band noise as claimed in claim 8, characterized in that: The conductive microstructure is linear.

10. The finger electrocardiogram signal extraction device with reduced in-band noise as claimed in claim 9, characterized in that: The line diameter of the conductive microstructure is 1 micron to 10 microns.

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