Bioelectric dry electrode with adjustable shape and pressure

Abstract

The invention discloses a bioelectric dry electrode with adjustable shape and pressure. The bioelectric dry electrode comprises an electrode substrate, a signal amplification circuit board and a plurality of telescopic dry electrode units fixedly arranged on the signal amplification circuit board. The electrode substrate comprises a flexible substrate and a button electrode male button; the signal amplification circuit board comprises a signal amplification circuit module and a pressure sensing module, the front surface of the signal amplification circuit board is fixedly connected with the plurality of telescopic dry electrode units, and the back surface of the signal amplification circuit board is connected with the electrode substrate; the telescopic dry electrode unit comprises a dry electrode top element, an elastic supporting element and a dry electrode base, one end of the elastic supporting element is fixed to the dry electrode base, and the other end of the elastic supporting element is connected with a lower pressing plate of the electrode top element. According to the self-adaptive bioelectricity acquisition dry electrode, the top element of the dry electrode can stretch out and draw back according to different shapes of contact surfaces, so that the electrode is adaptive to different contact surfaces, the discomfort during use is reduced, and the comfort level of user experience is improved; the signal amplification circuit board can carry out in-situ amplification on signals collected by the electrode unit, and high-quality detection of weak signals is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of brain-computer interfaces, and particularly relates to a bioelectric dry electrode with adjustable shape and pressure. Background Art

[0002] Bioelectric signals are one of the most basic physiological signals of the human body. The main bioelectric signals usually collected in the human body are electrocardiogram, electroencephalogram, electromyogram and electrooculogram signals. Bioelectric acquisition electrodes can be mainly divided into wet electrodes, dry electrodes and capacitive electrodes. Currently, the commonly used wet electrodes are widely used for the measurement of physiological electrical signals in medical institutions due to their low cost, low polarization effect, low electrode-skin interface impedance and ease of use. However, the use of wet electrodes will encounter problems such as the need for skin pretreatment and post-treatment, the inability to wear the electrodes alone, the need to inject conductive paste into the electrodes, and the residual conductive paste after testing will cause skin irritation. At the same time, as the conductive liquid volatilizes and evaporates, the skin-electrode interface impedance will increase, which is not suitable for long-term chronic electrophysiological signal monitoring.

[0003] Dry electrodes do not require skin pretreatment and the application of conductive gel, have good stretchability and portability, and at the same time have advantages such as small size, low cost and a more stable skin contact interface, and are expected to meet the needs of long-term bioelectric monitoring on the human body surface. Currently, the commonly used dry electrodes are mainly traditional block metal electrodes, metal or flexible material electrodes with columnar or comb-like structures. The side of the dry electrode in contact with the scalp is fixed and cannot have a good contact environment with the uneven human skin with pits and bumps, resulting in large electrode impedance and unstable electroencephalogram signals collected. A bioelectric dry electrode with adjustable shape and pressure is provided. Summary of the Invention

[0004] In view of the above problems, the present invention aims to overcome the defects of the prior art, solve the problems that the existing bioelectric acquisition dry electrodes have insufficient tightness in contact with the skin and unstable acquisition of weak signals, and at the same time solve the problem of in-situ amplification of bioelectric signals, and provides a bioelectric dry electrode with adjustable shape and pressure to solve multiple technical problems existing in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solution: A bioelectric dry electrode with adjustable shape and pressure, characterized in that: it includes a microstructure layer, a signal amplification module, and a base layer; the microstructure layer includes a plurality of dry electrode units and a flexible encapsulation layer; the signal amplification module includes a PCB substrate, an amplifier with a very high common-mode rejection ratio, and a pressure sensing module; the base layer includes a flexible base film covering the PCB substrate and a male buckle of a magnetic attraction interface; the electrode units in the microstructure layer are connected to the PCB substrate; the flexible encapsulation layer in the microstructure layer is connected to the bottoms of a plurality of electrode units and the PCB board; the signal amplification module and the pressure sensing module are connected to the PCB substrate through a circuit; in the base layer, the flexible base film is connected to the bottom end of the magnetic attraction interface male buckle, and the other end of the flexible base film is connected to the PCB substrate.

[0006] Further, in the present invention, the plurality of dry electrode units are arranged in an array; the dry electrode unit is composed of a dry electrode top element, a dry electrode bottom element, and an elastic support element; the dry electrode top element and the dry electrode bottom element are cylindrical elements, and are connected in an axial movement manner; the top end of the dry electrode top element is hemispherical, and the bottom end of the dry electrode top element is connected to the inner wall of the dry electrode bottom element to perform relative sliding movement; the upper end of the dry electrode bottom element is a stepped through hole, and the bottom end of the dry electrode bottom element is a circular chassis; the spring support element is axially installed in the stepped through hole of the dry electrode bottom element, the upper end of the elastic support element is connected to the dry electrode top element, and the lower end of the elastic support element is connected to the circular chassis of the dry electrode bottom element.

[0007] Further, the signal amplification module of the present invention is composed of a PCB substrate, an amplifier with a very high common-mode rejection ratio, and a pressure sensing module; circular pads are arranged in an array on the top surface of the PCB substrate and are connected to the circular chassis of the dry electrode bottom element; a circular pad is arranged at the center of the bottom surface of the PCB substrate and is connected to the bottom surface of the male buckle of the magnetic attraction interface of the base layer; a certain number of amplifiers with a high common-mode rejection ratio are arranged on the PCB substrate, the input end of the amplifier is connected to the circular pads arranged in an array, and the output end of the amplifier is connected to the circular pad at the center of the bottom surface of the PCB substrate; a pressure sensing module is arranged on the PCB substrate, the input end of the pressure sensing module is connected to the dry electrode bottom element, and the output end of the pressure sensing module is connected to the circular pad at the center of the bottom surface of the PCB substrate.

[0008] Further, the bioelectric dry electrode with adjustable shape and pressure of the present invention is characterized in that: the dry electrode top element, the dry electrode bottom element, and the elastic support element are all made of conductive materials.

[0009] Further, the bioelectric dry electrode with adjustable shape and pressure of the present invention is characterized in that: the dry elastic support element can adjust the spring length and elastic strength.

[0010] Furthermore, for a bioelectric dry electrode with adjustable shape and pressure according to the present invention, it is characterized in that the flexible encapsulation layer in the microstructure layer is made of an elastic and plastic material.

[0011] Furthermore, for a bioelectric dry electrode with adjustable shape and pressure according to the present invention, it is characterized in that the lower contact surface of the flexible encapsulation layer in the microstructure layer is connected to the upper contact surface of the flexible substrate film in the base layer.

[0012] Furthermore, during the bioelectric signal acquisition process of the present invention, the signal amplification module will amplify the original bioelectric signal in situ, and the amplified signal is transmitted out through the male magnetic interface.

[0013] The present invention has the following advantages compared with the prior art: (1) The top of the dry electrode can freely stretch in length, and can adapt to the human body surface through the elastic support element, improving the contact area between the electrode and the human body. (2) The stretching pressure at the top of the electrode is adjustable, enhancing the wearing comfort of the dry electrode. (3) A signal amplification circuit is provided at the bottom end of the electrode, enabling in-situ amplification of the acquired signal. (4) The adaptive bioelectric dry electrode can sense the pressure on the surface of the object to be measured, realizing the comfort monitoring during long-term wearing of the dry electrode. (5) The button male head and the electrode base are integrated components, improving the stability of signal transmission. Description of the Drawings

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly describe the drawings required for the description of the embodiments. Obviously, the described drawings are only a part of the embodiments of the present invention, rather than all the embodiments. Those skilled in the art can also obtain other design solutions and drawings based on these drawings without creative efforts.

[0015] Figure 1 It is a schematic diagram of the overall structure of the embodiment of the present invention;

[0016] Figure 2 It is the before-and-after effect diagram of the use of the bioelectric dry electrode in the embodiment of the present invention;

[0017] Figure 3 It is a schematic diagram of the signal amplification module in the embodiment of the present invention;

[0018] Figure 4 It is a schematic diagram of the base layer of the present invention;

[0019] Figure 5 It is a structural diagram of the dry electrode unit of the present invention;

[0020] Figure 6 It is a schematic diagram of the signal amplification circuit principle of the present invention;

[0021] In the figure: 1 microstructure layer, 2 signal amplification module, 3 base layer, 4 flexible encapsulation layer, 5 PCB substrate, 6 amplifier with a very large common-mode rejection ratio, 7 dry electrode unit mounting pad, 8 outer layer of the base layer, 9 amplifier mounting hole, 10 male magnetic interface, 11 pressure sensor, 12 bottom element of the dry electrode, 13 elastic support element, 14 top element of the dry electrode, 15 input bioelectric signal, 16 signal amplification circuit, 17 signal acquisition module. Specific implementation mode

[0022] The embodiments of the present invention will be described in detail below, enabling those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The examples of the embodiments are shown in the drawings, and the general principles defined therein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, these embodiments are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0023] As Figure 1 As shown in the appearance structure of a bioelectric dry electrode with adjustable shape and pressure of a preferred embodiment of the present invention, it includes a microstructure layer 1, a signal amplification module 2, and a base layer 3; the microstructure layer includes a plurality of dry electrode units and a flexible encapsulation layer 4; the signal amplification module 2 includes a PCB substrate 5, an amplifier 6 with a very large common-mode rejection ratio, and a pressure sensing module 11. There are pads 7 for mounting dry electrode units on the PCB substrate; the base layer 3 includes a flexible base film 8 covering the PCB board and a male magnetic interface 10; the bottom element of the electrode unit in the microstructure layer 1 passes through the flexible encapsulation layer 4 and is connected to the mounting pad 8 in the PCB substrate 5 by welding; the flexible encapsulation layer 4 in the microstructure layer 1 is connected to the bottom 12 of a plurality of electrode units and the PCB substrate 5, playing the role of encapsulating the upper panel of the PCB and fixing the dry electrode units; the signal amplification module 2 and the pressure sensing module 11 are connected to the PCB substrate 5 through a circuit to realize the amplification and monitoring of the physiological signals collected by the dry electrode units; the flexible base film 8 and the bottom end of the male magnetic interface 10 in the base layer 3 are connected, and the other end of the flexible base film 3 is connected to the PCB substrate 5, playing the role of encapsulating the lower panel of the PCB.

[0024] As Figure 5As shown in the structure of the dry electrode unit of the preferred embodiment of the present invention, the plurality of dry electrode units are arranged in an array and are arranged on the PCB substrate according to a certain rule; the dry electrode unit is composed of a dry electrode top element 14, a dry electrode bottom element 12 and an elastic support element 13; the material of the dry electrode unit is a conductive metal or a polymer conductive material; the dry electrode top element 14 contacts the cortical layer of the human scalp, and the surfaces of the dry electrode top element and the dry electrode bottom element are coated with silver / silver chloride or gold to reduce the influence of the electrode polarization voltage; the dry electrode top element 14 and the dry electrode bottom element 12 are cylindrical elements and are connected in an axial movement manner, and the dry electrode top element 14 is sleeved inside the dry electrode bottom element 12; the top end of the dry electrode top element 14 is hemispherical, and the bottom end of the dry electrode top element 14 is connected to the inner wall of the dry electrode bottom element 12 to perform a relative sliding movement; the upper end of the dry electrode bottom element 12 is a stepped through hole, and the bottom end of the dry electrode bottom element 12 is a circular chassis; the spring support element 13 is axially installed in the stepped through hole of the dry electrode bottom element 12, the upper end of the elastic support element 13 is connected to the dry electrode top element 14, and the lower end of the elastic support element 13 is connected to the circular chassis of the dry electrode bottom element 12; when the dry electrode top element 14 contacts the surface of the object to be measured. The elastic support element 13 can adjust the telescopic distance between the dry electrode top element 14 and the dry electrode bottom element 12 according to the set pressure value, adapt to the surface shape of the object to be measured, and improve the stability of signal acquisition.

[0025] The signal amplification module 2 includes a PCB substrate 5, an amplifier 6 with a very high common-mode rejection ratio, and a pressure sensing module 11; the PCB substrate 5 is a four-layer board; on the top surface of the PCB substrate 5, circular pads 7 are arranged in an array and connected to the bottom elements 12 of the dry electrodes; at the center of the bottom surface of the PCB substrate 5, a circular pad is arranged and connected to the bottom surface of the male buckle of the magnetic attraction interface 10 of the base layer 3; a certain number of amplifiers 6 with a high common-mode rejection ratio are arranged on the PCB substrate 5. The amplifier 6 with a high common-mode rejection ratio selects a 24-bit AD conversion module ADS1263. The input end of the amplifier is connected to the circular pads 7 arranged in an array, and the signals collected by the dry electrode unit are transmitted into the amplifier 6 with a very high common-mode rejection ratio through the circular pads 7; the bioelectric signals 15 collected are input into the signal amplification circuit 16 through the microstructural layer 1. The bioelectric signals are amplified 1000 times in situ by the signal amplification circuit 16 in the amplifier 6 with a high common-mode rejection ratio. The output end of the signal amplification circuit 16 is connected to the circular pad at the center of the bottom surface of the PCB substrate 5. The amplified bioelectric signals 15 are transmitted to the magnetic attraction interface 10 of the base layer 3 through the circular pad at the center of the bottom surface of the PCB substrate 5 and then transmitted into the signal acquisition module 17 for subsequent processing; a pressure sensing module 11 is arranged on the PCB substrate. The input end of the pressure sensing module 11 is connected to the bottom elements 12 of the dry electrodes, and the output end of the pressure sensing module 11 is connected to the circular pad at the center of the bottom surface of the PCB substrate 5. The monitoring data is transmitted through the magnetic attraction interface 10 of the base layer 3.

[0026] The top element of the dry electrode, the bottom element of the dry electrode, and the elastic support element are all made of conductive materials. In this embodiment, dry electrode elements with gold plating on the surface are selected; the total length of the dry electrode is 7.31 mm, the length of the top element of the dry electrode is 2.10 mm, and the length of the bottom element of the dry electrode is 5.21 mm; in this embodiment, the diameter of the PCB substrate 5 is 14.5 mm and the thickness is 1.5 mm; in this embodiment, 7 dry electrode units are welded in a circular array on the PCB substrate 5 with a diameter of 14.5 mm; the flexible encapsulation layer 4 selects polydimethylsiloxane (PDMS) for encapsulating the bottom of the dry electrode and the PCB substrate 5, and the encapsulation thickness is 2 mm.

[0027] The elastic support element of the dry electrode can adjust the spring length and elastic strength. In this embodiment, the rebound of the elastic support element of the dry electrode is 2 mm.

[0028] In this embodiment, the bottom element of the electrode unit in the microstructural layer 1 can also be electrically connected to the PCB substrate 5 by means of rivet installation through the flexible encapsulation layer 4.

[0029] The signal amplification module amplifies and filters the collected bioelectric signals, and at the same time suppresses the interference of common-mode noise. In this embodiment, ADS1291 is selected as the amplifier 6 with a very large common-mode rejection ratio, and the VQFN(RSM) package is selected, with a size of 4mm * 4mm. The pressure sensing module 11 selects 1-3 piezoelectric composite materials.

[0030] The flexible encapsulation layer in the microstructure layer is made of an elastic and plastic material. In this embodiment, polydimethylsiloxane (PDMS) is selected.

[0031] The lower contact surface of the flexible encapsulation layer in the microstructure layer is connected to the upper contact surface of the flexible substrate film in the base layer.

Claims

1. A bioelectric dry electrode with adjustable shape and pressure, characterized in that: It comprises a microstructure layer, a signal amplification module and a base layer; the microstructure layer comprises a plurality of dry electrode units and a flexible packaging layer; the signal amplification module comprises a PCB substrate, an amplifier with a large common mode rejection ratio and a pressure sensing module; the base layer comprises a flexible base film covering the PCB board and a male buckle of a magnetic interface; the electrode units in the microstructure layer are connected to the PCB substrate; the flexible packaging layer in the microstructure layer is connected to the bottom of a plurality of electrode units and the PCB board; the signal amplification module and the pressure sensing module are connected to the PCB substrate through a circuit; the flexible base film in the base layer is connected to the bottom end of the male buckle of the magnetic interface, and the other end of the flexible base film is connected to the PCB substrate.

2. The shape and pressure adjustable bioelectric dry electrode according to claim 1, characterized in that: The plurality of dry electrode units are distributed in an array; the dry electrode unit comprises a dry electrode top element, a dry electrode bottom element and an elastic supporting element; the dry electrode top component and the dry electrode bottom element are cylindrical elements, which are connected in an axial motion manner; the top end of the dry electrode top element is hemispherical, and the bottom end of the dry electrode top element is connected to the inner wall of the dry electrode bottom element for relative sliding motion; the upper end of the dry electrode bottom element is a stepped through hole, and the bottom end of the dry electrode bottom element is a circular chassis; the spring supporting element is axially installed in the stepped through hole of the dry electrode bottom element, the upper end of the elastic supporting element is connected to the dry electrode top element, and the lower end of the elastic supporting element is connected to the circular chassis of the dry electrode bottom element.

3. The shape and pressure adjustable bioelectric dry electrode according to claim 1, characterized in that: The signal amplification module comprises a PCB substrate, an amplifier with a large common mode rejection ratio and a pressure sensing module; the top surface of the PCB substrate is provided with an array of circular pads connected to the circular bottom plate of the dry electrode bottom element; the center of the bottom surface of the PCB substrate is provided with a circular pad connected to the bottom surface of the magnetic interface male buckle of the base layer; a certain number of amplifiers with a large common mode rejection ratio are provided on the PCB substrate, the input end of the amplifier is connected to the array of circular pads, and the output end of the amplifier is connected to the circular pad in the center of the bottom surface of the PCB substrate; the PCB substrate is provided with a pressure sensing module, the input end of the pressure sensing module is connected to the dry electrode bottom element, and the output end of the pressure sensing module is connected to the circular pad in the center of the bottom surface of the PCB substrate.

4. The shape and pressure adjustable bioelectric dry electrode according to claim 2, characterized in that: The dry electrode top element, the dry electrode bottom element and the elastic supporting element are all made of conductive materials.

5. The shape and pressure adjustable bioelectric dry electrode according to claim 2, characterized in that: The elastic supporting element can adjust the spring length and elastic strength.

6. The shape and pressure adjustable bioelectric dry electrode according to claim 1, characterized in that: The flexible packaging layer in the microstructure layer is made of elastic plastic material.

7. The shape and pressure adjustable bioelectric dry electrode according to claim 1, characterized in that: The lower contact surface of the flexible encapsulation layer in the microstructure layer is connected to the upper contact surface of the flexible base film in the base layer.

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