Rigid-flex active electrode device, equipment and system

Abstract

The embodiment of the invention relates to the technical field of electroencephalogram signal processing and brain-computer interfaces, and provides a rigid-flex active electrode device, equipment and a system. The device comprises a reference electrode, a bias driving electrode module, a first movable electrode module, a second movable electrode module, a third movable electrode module, a fourth movable electrode module, a fifth movable electrode module, a sixth movable electrode module, a seventh movable electrode module, an eighth movable electrode module and an interface module, the reference electrode comprises a buffer drive circuit and a wet electrode plate, and the signal-to-noise ratio of collected electroencephalogram signals can be increased.

Description

Technical Field

[0001] The present application relates to the technical field of electroencephalogram (EEG) signal processing and brain-computer interface, and specifically to a rigid-flexible active electrode device, equipment and system. Background Art

[0002] Obtaining stable and reliable EEG signals is the premise of scalp brain-computer interface technology. Electroencephalogram (EEG) is the spontaneous bioelectric activity at the scale of brain cell groups. EEG signals are usually very weak, with an amplitude generally between 1 and 100 μV, and are easily interfered by various physiological and environmental noises, which reduces the signal-to-noise ratio. Among them, electromagnetic interference is the most critical noise, such as the 1 / f noise of the components themselves, the thermal noise generated by the circuit, the 50Hz mains frequency noise, and the differential mode noise caused by the circuit asymmetry, DC bias error, etc. In order to reduce the impact of these noises and improve the signal-to-noise ratio, it is necessary to continuously improve the EEG signal conditioning and acquisition system, which is crucial to improving the accuracy and reliability of EEG signal research.

[0003] EEG signal acquisition based on dry electrodes is prone to introduce more noise interference due to the high contact impedance between the dry electrodes and the skin, resulting in a low signal-to-noise ratio of the collected EEG signals, and the clarity and accuracy of the signal are affected to a certain extent; and the contact state between the electrode and the skin may be affected by many factors, such as sweating, oil secretion, hair interference, etc., which may cause large signal fluctuations and result in a low signal-to-noise ratio of the collected EEG signals. Summary of the invention

[0004] The embodiments of the present application provide a rigid-flex active electrode device, equipment and system that can improve the signal-to-noise ratio of collected EEG signals.

[0005] A first aspect of an embodiment of the present application provides a rigid-flexible active electrode device, which is applied to an EEG signal acquisition system. The device includes: a reference electrode, a bias drive electrode module, a first active electrode module, a second active electrode module, a third active electrode module, a fourth active electrode module, a fifth active electrode module, a sixth active electrode module, a seventh active electrode module, an eighth active electrode module and an interface module. The reference electrode includes a buffer drive circuit and a wet electrode sheet, wherein:

[0006] The ninth input interface to the sixteenth input interface of the interface module are respectively connected to the output interface of the first active electrode module to the output interface of the eighth active electrode module through the flexible board, the first interface of the interface module is connected to the output interface of the buffer drive circuit through the flexible board, the input interface of the buffer drive circuit is connected to the wet electrode sheet through the electrode wire, and the second interface of the interface module is connected to the output interface of the bias drive electrode module through the flexible board;

[0007] The first active electrode module, the second active electrode module, the third active electrode module, the fourth active electrode module, the fifth active electrode module, the sixth active electrode module, the seventh active electrode module and the eighth active electrode module are used to collect the user's EEG signal;

[0008] The reference electrode is used to collect a reference signal of the EEG signal by connecting to the wet electrode sheet at the mastoid of the user;

[0009] The bias driving electrode module is used to collect the common mode bias voltage signal corresponding to the EEG signal and the reference signal from the user;

[0010] The rigid-flexible active electrode device sends the EEG signal, the reference signal and the common-mode bias voltage signal to the EEG signal multi-stage conditioning and amplification device through the interface module.

[0011] In this example, the interface module is connected to the remaining electrode modules through a flexible board, and the flexible board is made using a rolled copper process, so that the ductility, bending resistance and conductivity of the rigid-flexible active electrode device are better than the usual electrolytic copper process. At the same time, it also provides a good electrical reference plane for EEG signal transmission, effectively ensuring signal integrity, greatly reducing the electromagnetic interference of EEG signals due to wire transmission, and improving the signal-to-noise ratio of EEG signals.

[0012] In a specific implementation, the first active electrode module includes a first active electrode and a first buffer driving circuit, the first buffer driving circuit includes a first gain buffer, a first resistor, a second resistor, a third resistor, a thirteenth resistor, a thirty-ninth resistor, a fifth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor and a first electrostatic diode, wherein:

[0013] The first active electrode is connected to the first port, the fifth port, the sixth port, and the tenth port of the first gain buffer through the thirty-ninth capacitor, the first end of the first electrostatic diode is connected between the first active electrode and the port connected to the thirty-ninth resistor, and the second end of the second electrostatic diode is grounded, the second port of the first gain buffer is connected to the output interface of the first active electrode through the thirteenth resistor, the fourth port of the first gain buffer is connected to the output interface of the first active electrode through the first resistor, the seventh port of the first gain buffer is connected to the output interface of the first active electrode through the second resistor, the ninth port of the first gain buffer is connected to the output interface of the first active electrode through the third resistor, the third port of the first gain buffer is connected to the first end of the fifth capacitor, the first end of the tenth capacitor, and the first end of the eleventh capacitor, the first end of the tenth capacitor and the second end of the eleventh capacitor are connected and then grounded, the eighth port of the first gain buffer is connected to the second end of the fifth capacitor, the first end of the twelfth capacitor, and the first end of the thirteenth capacitor, the second end of the twelfth capacitor is connected to the second end of the thirteenth capacitor and then grounded;

[0014] The eighth port of the first gain buffer is a negative power supply port, and the third port of the first gain buffer is a positive power supply port.

[0015] In this example, a first electrostatic diode is set at the input end of the first gain buffer, which can reduce the damage of the first gain buffer caused by electrostatic discharge and improve the safety of the first gain buffer; and a plurality of capacitors are set at the positive and negative power supply ports of the first gain buffer, which can filter out high-frequency interference in the power supply and improve the stability of the power supply voltage.

[0016] In a specific implementation, the first gain buffer is an AD8244 chip, and the first electrostatic diode is an ESD electrostatic diode.

[0017] In a specific implementation, the tenth capacitor, the eleventh capacitor, the twelfth capacitor, and the thirteenth capacitor are decoupling capacitors, and the fifth capacitor is a ceramic capacitor.

[0018] In a specific implementation, the bias driving electrode module includes a bias driving electrode, a ninth electrostatic diode and a thirty-third resistor, wherein:

[0019] The output end of the bias driving electrode is connected to the first end of the ninth electrostatic diode and the first end of the thirty-third resistor, the second end of the ninth electrostatic diode is grounded, and the second end of the thirty-third resistor is the output end of the bias driving electrode module.

[0020] In this example, the thirty-third resistor is connected in series to ensure impedance matching on the signal transmission link, prevent signal reflection, contribute to signal integrity, and effectively suppress noise interference; the ninth electrostatic diode is terminated at the electrode to avoid the influence of static electricity on the previous signal output circuit and improve performance.

[0021] In a specific implementation, the thirty-third resistor is used to perform impedance matching on the bias drive electrode module.

[0022] In a specific implementation, the circuit boards corresponding to the reference electrode, bias drive electrode module and the first active electrode module, the second active electrode module, the third active electrode module, the fourth active electrode module, the fifth active electrode module, the sixth active electrode module, the seventh active electrode module and the eighth active electrode module are FR4 hard boards.

[0023] In a specific implementation, the FR4 hard board includes a top layer, a GND layer, an intermediate signal layer, a -2.5V power layer, a +2.5V power layer and a bottom layer, wherein:

[0024] The GND layer, the intermediate signal layer, the -2.5V power layer, and the +2.5V power layer are sequentially arranged between the top layer and the bottom layer, the intermediate signal layer is arranged adjacent to the top layer, the +2.5V power layer is arranged adjacent to the bottom layer, and the intermediate signal layer is used for signal transmission.

[0025] In this example, the signal is transmitted in the middle signal layer and is sandwiched by the complete bottom layer and power layer, which provides a good electrical reference plane for EEG signal transmission, effectively ensures signal integrity, reduces electromagnetic interference to EEG signals caused by wire transmission, and helps improve the signal-to-noise ratio.

[0026] A second aspect of an embodiment of the present application provides a rigid-flex active electrode device, comprising a shell and a rigid-flex active electrode device as described in any one of the first aspects, wherein the rigid-flex active electrode device is arranged inside the shell.

[0027] The second aspect of an embodiment of the present application provides a high signal-to-noise ratio dry electrode EEG signal acquisition system, which includes an EEG signal multi-stage conditioning and amplification device and a rigid-flexible active electrode device as described in the second aspect, wherein the rigid-flexible active electrode device is connected to the EEG signal multi-stage conditioning and amplification device, and the rigid-flexible active electrode device is used to send the collected EEG signal, reference signal and common-mode bias voltage signal to the EEG signal multi-stage conditioning and amplification device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the structure of a high signal-to-noise ratio dry electrode EEG signal acquisition system is provided for an embodiment of the present application;

[0030] Figure 2 A structural schematic diagram of a rigid-flex active electrode device is provided for an embodiment of the present application;

[0031] Figure 3 A structural schematic diagram of a first movable electrode module is provided for an embodiment of the present application;

[0032] Figure 4 A schematic structural diagram of a bias driving electrode module is provided for an embodiment of the present application;

[0033] Figure 5 A schematic diagram of the architecture of an FR4 hard board is provided for an embodiment of the present application;

[0034] Figure 6 A schematic diagram of the architecture of a flexible board is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0037] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0038] In order to better understand the rigid-flexible active electrode device provided in the embodiment of the present application, the EEG signal acquisition scheme in the existing scheme is briefly introduced below.

[0039] The EEG acquisition and amplification circuit based on wet electrodes is relatively mature. However, wet electrodes have problems such as long preparation time and inconvenience in wearing, which seriously restrict the practical application of brain-computer interfaces. The EEG signal acquisition based on dry electrodes is prone to introduce more noise interference due to the high contact impedance between the dry electrodes and the skin, resulting in a low signal-to-noise ratio of the collected EEG signals, and the clarity and accuracy of the signal are affected to a certain extent. In addition, the contact state between the electrode and the skin may be affected by many factors, such as sweating, oil secretion, hair interference, etc., which leads to large signal fluctuations, and puts higher requirements on the filtering, amplification, and acquisition of EEG signals.

[0040] At present, a variety of control algorithms have emerged in software design, which have improved the signal-to-noise ratio of EEG signals to a certain extent, but have prolonged the data processing time and reduced the real-time performance of the system. In terms of hardware design, the structure of EEG acquisition devices using active electrodes + conditioning acquisition circuits has emerged. Although this structure is relatively complex, it can enhance the anti-interference ability of EEG signals at the source, which helps to improve its signal-to-noise ratio and is a technical means with great application prospects. However, the circuit principle and structure, PCB layout and wiring, and stacking structure design of active electrodes, especially under the conditions of dry electrode application, directly affect the integrity and anti-interference ability of EEG signals; and the front-end analog conditioning circuits of EEG acquisition devices, such as low-pass filtering, high-pass filtering, multi-stage amplification, AD conversion, etc., their circuit principles, front-end interconnection relationships, electrical parameter matching and other factors also affect the transmission integrity and noise suppression ability of EEG signals, and the system needs to be comprehensively designed to ensure signal quality. Therefore, the research on EEG acquisition devices with high signal-to-noise ratio still faces various technical challenges.

[0041] The main technical problems of the current EEG acquisition device using active electrodes + multi-stage conditioning circuits are:

[0042] The wire connection of the active electrode is prone to electromagnetic interference. In the existing solutions, the active electrode is mostly designed with a hard board made of FR4 material + a soft and long wire. The EEG signal is easily affected by electromagnetic interference when it is transmitted in the wire, and the EEG signal does not have a good electrical reference plane. The signal integrity is also greatly affected, which is not conducive to improving the signal-to-noise ratio;

[0043] The unreasonable circuit design of active electrodes affects the integrity of EEG signals. The active electrode circuit contains a filter circuit. If it is in front of the buffer, the original characteristics of the EEG signal will be destroyed due to the large internal resistance of the EEG signal source; if it is close to the buffer and at the back end, the integrity of the EEG signal will be affected due to the large output impedance and long-line transmission problems.

[0044] The mismatch of electrical parameters between the active electrode circuit and the pre-conditioning amplifier circuit leads to poor signal quality after interconnection. The electrical parameter matching between the active electrode and the pre-conditioning amplifier circuit in the EEG acquisition device is not ideal, which seriously affects the signal integrity and signal-to-noise ratio during the EEG signal transmission process. Especially under the condition of dry electrode application, the design rationality and effectiveness of these two parts of the circuit face great technical challenges.

[0045] In order to solve the above-mentioned technical problems, the present application provides a rigid-flexible active electrode device, which can connect the interface module with the remaining electrode modules through a flexible board, and the flexible board is manufactured by a rolled copper process, so that the ductility, bending resistance and conductivity of the rigid-flexible active electrode device are better than the conventional electrolytic copper process. At the same time, it also provides a good electrical reference plane for EEG signal transmission, effectively ensures signal integrity, greatly reduces the electromagnetic interference of EEG signals due to wire transmission, and improves the signal-to-noise ratio of EEG signals.

[0046] See also Figure 1 , Figure 1 The present invention provides a schematic diagram of the structure of a high signal-to-noise ratio dry electrode EEG signal acquisition system. Figure 1 As shown, the high signal-to-noise ratio dry electrode EEG signal acquisition system 100 includes an EEG signal multi-stage conditioning and amplification device 200 and a rigid-flexible active electrode device 300, wherein the rigid-flexible active electrode device 300 is connected to the EEG signal multi-stage conditioning and amplification device 200, and the rigid-flexible active electrode device 300 is used to send the collected EEG signal and reference signal to the EEG signal multi-stage conditioning and amplification device 200, and receive a bias drive signal from the EEG signal multi-stage conditioning and amplification device 200;

[0047] After receiving the EEG signal and the reference signal, the EEG signal multi-stage conditioning and amplification device 200 performs filtering and differential amplification processing to obtain a final usable EEG signal, which greatly improves the signal quality and signal-to-noise ratio of the acquired EEG signal.

[0048] Specifically, the EEG signal multi-stage conditioning and amplification device 200 and the rigid-flexible active electrode device 300 use high-density and ultra-low-height board connectors AXT616124 and AXT516124 for plug-in interconnection. The terminals of the connectors are made of copper alloy and are electroplated with Ni on the bottom layer and Au on the surface, which improves the contact stability and durability.

[0049] See also Figure 2 , Figure 2 A structural schematic diagram of a rigid-flex active electrode device is provided for an embodiment of the present application. Figure 2 As shown, the rigid-flex active electrode device 300 includes: a reference electrode 1, a bias drive electrode module 2 and a first active electrode module 3, a second active electrode module 4, a third active electrode module 5, a fourth active electrode module 6, a fifth active electrode module 7, a sixth active electrode module 8, a seventh active electrode module 9, an eighth active electrode module 10 and an interface module 11, wherein the reference electrode 1 includes a buffer drive circuit 111 and a wet electrode sheet 112, wherein:

[0050] The ninth input interface to the sixteenth input interface of the interface module 11 are respectively connected to the corresponding output interface of the first active electrode module 3 to the output interface of the eighth active electrode module 10 through a flexible board, the first interface of the interface module 11 is connected to the output interface of the buffer drive circuit 111 through a flexible board, the input interface of the buffer drive circuit 111 is connected to the wet electrode sheet 112 through an electrode wire, and the second interface of the interface module 11 is connected to the output interface of the bias drive electrode module 2 through a flexible board, and the flexible board is made by a rolled copper process;

[0051] The first active electrode module 3, the second active electrode module 4, the third active electrode module 5, the fourth active electrode module 6, the fifth active electrode module 7, the sixth active electrode module 8, the seventh active electrode module 9 and the eighth active electrode module 10 are used to collect the user's EEG signal;

[0052] The reference electrode 1 is used to collect the reference signal of the EEG signal by connecting to the wet electrode sheet 112 at the mastoid of the user;

[0053] The bias driving electrode module 2 is used to obtain a common mode bias voltage signal corresponding to an EEG signal from a user;

[0054] The rigid-flex active electrode device interconnects the EEG signal, reference signal, common-mode bias voltage signal, and power supply with the EEG signal multi-stage conditioning and amplification device 200 through the interface module 11 .

[0055] in, Figure 2The wiring structure diagram of the rigid-flex active electrode device is shown in FIG. The dotted line connection between the electrodes is used to indicate that the circuit connection is made by a flexible board instead of a wire connection. The buffer drive circuit 111 and the wet electrode sheet 112 in the reference electrode 1 are connected by an electrode wire.

[0056] In this example, the interface module 11 is connected to the remaining electrode modules through a flexible board, and the flexible board is made using a rolled copper process, so that the ductility, bending resistance and conductivity of the rigid-flexible active electrode device are better than the conventional electrolytic copper process. At the same time, it also provides a good electrical reference plane for EEG signal transmission, effectively ensuring signal integrity, greatly reducing the electromagnetic interference of EEG signals due to wire transmission, and improving the signal-to-noise ratio of EEG signals.

[0057] In a specific implementation, Figure 3 As shown, the first active electrode module 3 includes a first active electrode 31 and a first buffer driving circuit, the first buffer driving circuit includes a first gain buffer 321, a first resistor R1, a second resistor R2, a third resistor R3, a thirteenth resistor R13, a thirty-ninth resistor R39, a fifth capacitor C5, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a thirteenth capacitor C13 and a first electrostatic diode D1, wherein,

[0058] The first active electrode 31 is connected to the first port, the fifth port, the sixth port, and the tenth port of the first gain buffer 321 through the thirty-ninth capacitor, the first end of the first electrostatic diode D1 is connected between the first active electrode 31 and the port connected to the thirty-ninth resistor R39, and the second end of the second electrostatic diode is grounded, the second port of the first gain buffer 321 is connected to the output interface of the first active electrode 31 through the thirteenth resistor R13, the fourth port of the first gain buffer 321 is connected to the output interface of the first active electrode 31 through the first resistor R1, and the seventh port of the first gain buffer 321 is connected to the first active electrode 31 through the second resistor R2. The output interface of the first active electrode 31 is connected to the output interface of the first active electrode 31, the ninth port of the first gain buffer 321 is connected to the output interface of the first active electrode 31 through the third resistor R3, the third port of the first gain buffer 321 is connected to the first end of the fifth capacitor C5, the first end of the tenth capacitor C10, and the first end of the eleventh capacitor C11, the first end of the tenth capacitor C10 and the second end of the eleventh capacitor C11 are connected and then grounded, the eighth port of the first gain buffer 321 is connected to the second end of the fifth capacitor C5, the first end of the twelfth capacitor C12, and the first end of the thirteenth capacitor C13, the second end of the twelfth capacitor C12 is connected to the second end of the thirteenth capacitor C13 and then grounded;

[0059] The eighth port of the first gain buffer 321 is a negative power supply port, and the third port of the first gain buffer 321 is a positive power supply port.

[0060] The negative power supply port is represented by AVSS_-2V5, and the positive power supply port is represented by AVSS_2V5. The output port of the first active electrode module 3 is represented by CH OUT1, and the electrode connection pad is connected to the first active electrode.

[0061] Specifically, the circuit structures of the second movable electrode module 4 to the eighth movable electrode module 10 are the same as the circuit structure of the first movable electrode module 3 .

[0062] The circuit structure of the buffer driving circuit in the reference electrode 1 is the same as the circuit structure of the first buffer driving circuit.

[0063] In this example, a first electrostatic diode D1 is set at the input end of the first gain buffer 321, which can reduce the damage of the first gain buffer 321 caused by electrostatic discharge and improve the safety of the first gain buffer 321; and a plurality of capacitors are set at the positive and negative power supply ports of the first gain buffer 321, which can filter out high-frequency interference in the power supply and improve the stability of the power supply voltage.

[0064] In a specific implementation, the first gain buffer 321 is an AD8244 chip, the first electrostatic diode D1 is an ESD electrostatic diode, the tenth capacitor C10, the eleventh capacitor C11, the twelfth capacitor C12 and the thirteenth capacitor C13 are decoupling capacitors, and the fifth capacitor C5 is a ceramic capacitor.

[0065] Specifically, in a preferred embodiment, the capacity of the tenth capacitor C10 can be 0.1uF, the capacity of the eleventh capacitor C11 can be 4.7uF, the capacity of the twelfth capacitor C12 can be 0.1uF, the capacity of the thirteenth capacitor C13 can be 4.7uF, the capacity of the fifth capacitor C5 can be 4.7uF, and the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, and the thirteenth resistor R13 can be 51Ω. The above values ​​are only preferred embodiments, not all implementations of the present application, and the parameters that can specifically meet the corresponding performance indicators are in line with the technical solutions of the present application.

[0066] AD8244 is a four-channel unity gain buffer with a maximum bias current of 2pA, a current noise of 0.8fA, a voltage noise of 0.4uVpp, and an input impedance of 10TΩ. Therefore, even if the source impedance is at the MΩ level, there will be no input error due to the load effect. The output resistance of the device is basically zero, and the output voltage has a high load capacity. Figure 2 The structure of the first active electrode module 3 shown in the figure adopts a parallel structure of four buffers to realize the isolation buffering of one channel of EEG signal. This structure reduces the voltage noise density, and the effective value of the noise is reduced to half of the effective value of the noise when the single buffer is used, thereby improving the signal-to-noise ratio. A small resistor of 51Ω is placed at each buffer output pin, the main purpose of which is to prevent the flow of additional current caused by the slight difference between the outputs of each channel, and further improve the stability of the signal.

[0067] In a specific implementation, Figure 4 As shown, the bias driving electrode module 2 includes a bias driving electrode 21, a ninth electrostatic diode D9 and a thirty-third resistor R33, wherein:

[0068] The output end of the bias driving electrode 21 is connected to the first end of the ninth electrostatic diode D9 and the first end of the thirty-third resistor R33. The second end of the ninth electrostatic diode D9 is grounded. The second end of the thirty-third resistor R33 is the output end of the bias driving electrode module 2.

[0069] The electrode connection pad is connected to a bias driving electrode. The input port of the bias driving electrode module 2 is represented by OUT_BIAS.

[0070] The bias drive electrode module 2 is used to provide an electrical reference point for the user's body. The actual output is the common-mode reference voltage generated by the filter amplification acquisition device, which can reduce the common-mode interference of the EEG signal on the active electrode and the reference electrode 1. The thirty-third resistor R33 is connected in series to ensure impedance matching on the signal transmission link, prevent signal reflection, contribute to signal integrity, and effectively suppress noise interference; the ninth electrostatic diode D9 is terminated at the electrode to avoid the influence of static electricity on the front-stage signal output circuit and improve performance.

[0071] In a specific implementation, the thirty-third resistor R33 is used to perform impedance matching on the bias driving electrode module 2 .

[0072] In a specific implementation, the circuit boards corresponding to the reference electrode 1, the bias drive electrode module 2 and the first active electrode module 3, the second active electrode module 4, the third active electrode module 5, the fourth active electrode module 6, the fifth active electrode module 7, the sixth active electrode module 8, the seventh active electrode module 9 and the eighth active electrode module 10 are FR4 hard boards.

[0073] In a specific implementation, Figure 5 As shown, the FR4 hard board adopts a six-layer PCB architecture, and the stack includes a top layer, a GND layer, an intermediate signal layer, a -2.5V power layer, a +2.5V power layer and a bottom layer, wherein:

[0074] The GND layer, the intermediate signal layer, the -2.5V power layer, and the +2.5V power layer are sequentially arranged between the top layer and the bottom layer, the intermediate signal layer is arranged adjacent to the top layer, the +2.5V power layer is arranged adjacent to the bottom layer, and the intermediate signal layer is used for signal transmission.

[0075] Among them, the signals transmitted in the middle layer include EEG signals, reference signals, and common-mode bias voltage signals, etc. The signals are transmitted in the middle signal layer, sandwiched by the complete GND layer and power layer, which provides a good electrical reference plane for EEG signal transmission, effectively guarantees signal integrity, reduces electromagnetic interference to EEG signals caused by wire transmission, and helps improve the signal-to-noise ratio.

[0076] The flexible board adopts a four-layer PCB structure, which is the same as the middle four layers of the FR4 hard board. Figure 6 As described above, the stacking order from top to bottom is GND layer, middle signal layer, -2.5V power layer, +2.5V power layer. The signals on the electrodes are all transmitted in the middle signal layer of the flexible board, sandwiched between the complete GND layer and the power layer, providing a good electrical reference plane for EEG signal transmission, effectively ensuring signal integrity, reducing electromagnetic interference to EEG signals caused by wire transmission, and helping to improve the signal-to-noise ratio.

[0077] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0078] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0079] In the several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be electrical or other forms.

[0080] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0081] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A rigid-flex active electrode device, characterized in that: The device comprises: a reference electrode, a bias drive electrode module and a first active electrode module, a second active electrode module, a third active electrode module, a fourth active electrode module, a fifth active electrode module, a sixth active electrode module, a seventh active electrode module, an eighth active electrode module and an interface module, wherein the reference electrode comprises a buffer drive circuit and a wet electrode sheet, wherein: The ninth input interface to the sixteenth input interface of the interface module are respectively connected to the output interface of the first active electrode module to the output interface of the eighth active electrode module through the flexible board, the first interface of the interface module is connected to the output interface of the buffer drive circuit through the flexible board, the input interface of the buffer drive circuit is connected to the wet electrode sheet through the electrode wire, the second interface of the interface module is connected to the output interface of the bias drive electrode module through the flexible board, and the flexible board is made by the rolled copper process; The first active electrode module, the second active electrode module, the third active electrode module, the fourth active electrode module, the fifth active electrode module, the sixth active electrode module, the seventh active electrode module and the eighth active electrode module are used to collect the user's EEG signal; The reference electrode is used to collect a reference signal of the EEG signal by connecting to the wet electrode sheet at the mastoid of the user; The bias driving electrode module is used to collect the common mode bias voltage signal corresponding to the EEG signal and the reference signal from the user; The rigid-flexible active electrode device sends the EEG signal, the reference signal and the common-mode bias voltage signal to the EEG signal multi-stage conditioning and amplification device through the interface module.

2. The rigid-flex active electrode device according to claim 1, characterized in that: The first active electrode module includes a first active electrode and a first buffer driving circuit, the first buffer driving circuit includes a first gain buffer, a first resistor, a second resistor, a third resistor, a thirteenth resistor, a thirty-ninth resistor, a fifth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor and a first electrostatic diode, wherein: The first active electrode is connected to the first port, the fifth port, the sixth port, and the tenth port of the first gain buffer through the thirty-ninth capacitor, the first end of the first electrostatic diode is connected between the first active electrode and the port connected to the thirty-ninth resistor, and the second end of the second electrostatic diode is grounded, the second port of the first gain buffer is connected to the output interface of the first active electrode through the thirteenth resistor, the fourth port of the first gain buffer is connected to the output interface of the first active electrode through the first resistor, the seventh port of the first gain buffer is connected to the output interface of the first active electrode through the second resistor, the ninth port of the first gain buffer is connected to the output interface of the first active electrode through the third resistor, the third port of the first gain buffer is connected to the first end of the fifth capacitor, the first end of the tenth capacitor, and the first end of the eleventh capacitor, the first end of the tenth capacitor and the second end of the eleventh capacitor are connected and then grounded, the eighth port of the first gain buffer is connected to the second end of the fifth capacitor, the first end of the twelfth capacitor, and the first end of the thirteenth capacitor, the second end of the twelfth capacitor is connected to the second end of the thirteenth capacitor and then grounded; The eighth port of the first gain buffer is a negative power supply port, and the third port of the first gain buffer is a positive power supply port.

3. The rigid-flex active electrode device according to claim 2, characterized in that: The first gain buffer is an AD8244 chip, and the first electrostatic diode is an ESD electrostatic diode.

4. The rigid-flex active electrode device according to claim 2 or 3, characterized in that: The tenth capacitor, the eleventh capacitor, the twelfth capacitor and the thirteenth capacitor are decoupling capacitors, and the fifth capacitor is a ceramic capacitor.

5. The rigid-flex active electrode device according to claim 4, characterized in that: The bias driving electrode module includes a bias driving electrode, a ninth electrostatic diode and a thirty-third resistor, wherein: The output end of the bias driving electrode is connected to the first end of the ninth electrostatic diode and the first end of the thirty-third resistor, the second end of the ninth electrostatic diode is grounded, and the second end of the thirty-third resistor is the output end of the bias driving electrode module.

6. The rigid-flex active electrode device according to claim 5, characterized in that: The thirty-third resistor is used for impedance matching of the bias driving electrode module.

7. The rigid-flex active electrode device according to claim 6, characterized in that: The circuit boards corresponding to the reference electrode, the bias drive electrode module and the first active electrode module, the second active electrode module, the third active electrode module, the fourth active electrode module, the fifth active electrode module, the sixth active electrode module, the seventh active electrode module and the eighth active electrode module are FR4 hard boards.

8. The rigid-flex active electrode device according to claim 6, characterized in that: The FR4 hard board includes a top layer, a GND layer, an intermediate signal layer, a -2.5V power layer, a +2.5V power layer and a bottom layer, wherein: The GND layer, the intermediate signal layer, the -2.5V power layer, and the +2.5V power layer are sequentially arranged between the top layer and the bottom layer, the intermediate signal layer is arranged adjacent to the top layer, the +2.5V power layer is arranged adjacent to the bottom layer, and the intermediate signal layer is used for signal transmission.

9. A rigid-flex active electrode device, characterized in that: It comprises a shell and a rigid-flex active electrode device as described in any one of claims 1 to 8, wherein the rigid-flex active electrode device is arranged inside the shell.

10. A high signal-to-noise ratio dry electrode EEG signal acquisition system, characterized in that: The high signal-to-noise ratio dry electrode EEG signal acquisition system includes an EEG signal multi-stage conditioning and amplification device and a rigid-flexible active electrode device as described in any one of claims 1 to 8, wherein the rigid-flexible active electrode device is connected to the EEG signal multi-stage conditioning and amplification device, and the rigid-flexible active electrode device is used to send the collected EEG signal, reference signal and common-mode bias voltage signal to the EEG signal multi-stage conditioning and amplification device.

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