Flexible and rigidly combined active electrode devices, apparatuses and systems

Abstract

The embodiment of the application relates to the fields of electroencephalogram signal processing and brain-computer interface technology, and provides a rigid-flex active electrode device, equipment and system, the device comprises a reference electrode, a bias driving 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 comprises a buffer driving circuit and a wet electrode piece, and the signal-to-noise ratio of the collected electroencephalogram signal can be improved.

Description

Technical Field

[0001] The present application relates to the technical fields of electroencephalogram (EEG) signal processing and brain-computer interface (BCI), and in particular 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 with 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, the differential mode noise caused by circuit asymmetry, and DC bias error. 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 introducing 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 signals are affected to a certain extent; and the contact state between the electrodes and the skin may be affected by many factors, such as sweating, oil secretion, hair interference, etc., which may cause large signal fluctuations and 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-flex active electrode device, which is applied to an EEG signal acquisition system. The device includes: 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. The reference electrode includes a buffer drive circuit and a wet electrode sheet, wherein:

[0006] The ninth to sixteenth input interfaces of the interface module are respectively connected to the output interfaces of the first to eighth active electrode modules via flexible boards; the first interface of the interface module is connected to the output interface of the buffer drive circuit via a flexible board; the input interface of the buffer drive circuit is connected to the wet electrode sheet via an electrode wire; and the second interface of the interface module is connected to the output interface of the bias drive electrode module via a 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 electroencephalogram (EEG) signals;

[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 process 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-flex 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 manufactured using a rolled copper process, so that the ductility, bending resistance and conductivity of the rigid-flex active electrode device are better than those of 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.

[0012] In a specific implementation, the first movable electrode module includes a first movable 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 with 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 with the thirty-ninth resistor, the second end of the second electrostatic diode is grounded, the second port of the first gain buffer is connected with the output interface of the first active electrode through the thirteenth resistor, the fourth port of the first gain buffer is connected with the output interface of the first active electrode through the first resistor, the seventh port of the first gain buffer is connected with the output interface of the first active electrode through the second resistor, the ninth port of the first gain buffer is connected with the output interface of the first active electrode through the third resistor, the third port of the first gain buffer is connected with 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 grounded, the eighth port of the first gain buffer is connected with the second end of the fifth capacitor, the first end of the twelfth capacitor and the first end of the thirteenth capacitor, and the second end of the twelfth capacitor and the second end of the thirteenth capacitor are connected and 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 the example, the first electrostatic diode is arranged at the input end of the first gain buffer, so that the damage of electrostatic discharge to the first gain buffer is reduced, and the safety of the first gain buffer is improved; and the plurality of capacitors are arranged at the positive and negative power supply ports of the first gain buffer, so that the high-frequency disturbance quantity in the power supply is filtered out, and the stability of the power supply voltage is improved.

[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 comprises 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 with 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-stage signal output circuit, thereby improving 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, and the +2.5V power layer is arranged adjacent to the bottom layer. 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 between the intact bottom layer and power layer. This provides a good electrical reference plane for EEG signal transmission, effectively ensuring signal integrity, reducing electromagnetic interference on EEG signals caused by wire transmission, and helping to 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. 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0029] Figure 1 A schematic structural diagram 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 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 drive 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 this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0037] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, 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 following first briefly introduces the EEG signal acquisition solution in the existing solution.

[0039] EEG acquisition and amplification circuits based on wet electrodes are 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. EEG signal acquisition based on dry electrodes, due to the high contact impedance between dry electrodes and the skin, is prone to introducing more noise interference, resulting in a low signal-to-noise ratio of the collected EEG signals, which affects the clarity and accuracy of the signals. In addition, the contact state between the electrodes and the skin may be affected by various factors, such as sweating, oil secretion, and interference from hair, resulting in large signal fluctuations, which places higher requirements on the filtering, amplification, and acquisition of EEG signals.

[0040] Currently, various control algorithms have emerged in software design, which have improved the signal-to-noise ratio (SNR) of EEG signals to a certain extent, but this also increases data processing time and reduces the system's real-time performance. In hardware design, EEG acquisition devices employing active electrodes plus conditioning and acquisition circuitry have emerged. While relatively complex, this structure enhances interference rejection at the source of the EEG signal, helping to improve its SNR, making it a promising technology. However, the design of active electrodes, particularly dry electrodes, directly impacts EEG signal integrity and interference rejection, including their circuit principles and structure, PCB layout, and stack-up structure. Furthermore, the front-end analog conditioning circuitry of EEG acquisition devices, such as low-pass filtering, high-pass filtering, multi-stage amplification, and A / D conversion, also impacts EEG signal transmission integrity and noise suppression capabilities. Therefore, comprehensive system design is required to ensure signal quality. Therefore, research on EEG acquisition devices with high SNR 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 connections of active electrodes are prone to electromagnetic interference. Existing solutions often use a hard FR4 board with long, flexible wires. EEG signals are susceptible to electromagnetic interference when transmitted through the wires. Furthermore, the EEG signal lacks a good electrical reference plane, significantly impacting signal integrity and hindering signal-to-noise ratio improvement.

[0043] Improper active electrode circuit design can affect EEG signal integrity. If the active electrode circuit includes a filter circuit, placing it before the buffer can disrupt the original EEG signal characteristics due to the high internal resistance of the EEG signal source. If placed immediately after the buffer, the EEG signal integrity can be compromised due to high output impedance and long transmission lines.

[0044] Electrical parameter mismatches between the active electrode circuit and the pre-conditioning amplifier circuit lead to poor signal quality after interconnection. Less than ideal electrical parameter matching between the active electrode and the pre-conditioning amplifier circuit in EEG acquisition devices seriously affects signal integrity and signal-to-noise ratio during EEG signal transmission. This is particularly true when using dry electrodes, and the rationality and effectiveness of the design of these two circuit components present significant 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. The rigid-flexible active electrode device 300 is connected to the EEG signal multi-stage conditioning and amplification device 200. 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 the 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 the 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, 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 The present invention provides a structural diagram of a rigid-flex active electrode device. 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. The reference electrode 1 includes a buffer drive circuit 111 and a wet electrode sheet 112, wherein:

[0050] The ninth to sixteenth input interfaces of the interface module 11 are respectively connected to the corresponding output interfaces of the first to eighth active electrode modules 3 to 10 via flexible boards. The first interface of the interface module 11 is connected to the output interface of the buffer drive circuit 111 via a flexible board. The input interface of the buffer drive circuit 111 is connected to the wet electrode sheet 112 via an electrode wire. The second interface of the interface module 11 is connected to the output interface of the bias drive electrode module 2 via a flexible board, and the flexible board is manufactured using 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 electroencephalogram (EEG) signals;

[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 user's mastoid process;

[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 diagram of the rigid-flex active electrode device is shown in Figure 2. The dotted lines between the electrodes indicate that the circuit connections are made using a flexible board rather than wires. The buffer drive circuit 111 and the wet electrode sheet 112 in the reference electrode 1 are connected by electrode wires.

[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 movable electrode module 3 includes a first movable 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 with the first port, the fifth port, the sixth port and the tenth port of the third gain buffer 321 through the thirty-ninth capacitor, the first end of the first static diode D1 is connected between the first active electrode 31 and the port connected with the thirty-ninth resistor R39, the second end of the second static diode is grounded, the second port of the third gain buffer 321 is connected with the output interface of the first active electrode 31 through the thirteenth resistor R13, the fourth port of the third gain buffer 321 is connected with the output interface of the first active electrode 31 through the first resistor R1, the seventh port of the third gain buffer 321 is connected with the output interface of the first active electrode 31 through the second resistor R2, the ninth port of the third gain buffer 321 is connected with the output interface of the first active electrode 31 through the third resistor R3, the third port of the third gain buffer 321 is connected with 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 grounded, the eighth port of the third gain buffer 321 is connected with 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 and the second end of the thirteenth capacitor C13 are connected and grounded;

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

[0060] Wherein, 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 first active electrode is connected at the electrode connection pad.

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

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

[0063] In the example, the first static diode D1 is arranged at the input end of the third gain buffer 321, which can reduce the damage of electrostatic discharge to the third gain buffer 321 and improve the safety of the third gain buffer 321; and a plurality of capacitors are arranged at the positive and negative power supply ports of the third gain buffer 321, which can filter out high-frequency interference quantities 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 and not all implementations of the present application. The parameters that can specifically meet the corresponding performance indicators are in line with the technical solutions of the present application.

[0066] The 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 this device is essentially zero, and the output voltage has a high load capacity. Figure 2 The structure of the first active electrode module 3 shown uses four parallel buffers to isolate and buffer one EEG signal. This structure reduces voltage noise density, reducing the effective noise value to half that of a single buffer, thereby improving the signal-to-noise ratio. A small 51Ω resistor is placed at each buffer output pin to prevent additional current flow caused by slight differences between outputs, further improving signal stability.

[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 driving electrode module 2 is used to provide an electrical reference point for the human body of the user, and the actual output is a common-mode reference voltage generated by the filtering and amplifying collecting device, which can reduce the common-mode interference of the brain electrical signals on the active electrode and the reference electrode 1. The series connection of the thirty-third resistor R33 is to ensure impedance matching on the signal transmission link, prevent signal reflection, help signal integrity, and also effectively suppress noise interference; the ninth static diode D9 at the end of the electrode can avoid the influence of static electricity on the front-stage signal output circuit and improve performance.

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

[0072] In a specific implementation manner, the reference electrode 1, the bias driving 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 correspond to FR4 hard boards.

[0073] In a specific implementation manner, as shown in Figure 5 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 supply layer, a +2.5V power supply layer, and a bottom layer, wherein

[0074] the GND layer, the intermediate signal layer, the -2.5V power supply layer, and the +2.5V power supply layer are sequentially arranged between the top layer and the bottom layer, the intermediate signal layer is arranged adjacent to the top layer, and the +2.5V power supply 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 intermediate layer include brain electrical signals, reference signals, and common-mode bias voltage signals. The signals are transmitted in the intermediate signal layer and are sandwiched between the complete GND layer and the power supply layer, which provides a good electrical reference plane for brain electrical signal transmission, effectively guarantees signal integrity, reduces electromagnetic interference of brain electrical signals caused by wire transmission, and helps to improve the signal-to-noise ratio.

[0076] The flexible board adopts a four-layer PCB architecture, which is the same as the intermediate four layers of the FR4 hard board, as shown in Figure 6 the stack order from top to bottom is a GND layer, an intermediate signal layer, a -2.5V power supply layer, and a +2.5V power supply layer. The signals on the electrodes are all transmitted in the intermediate signal layer of the flexible board and are sandwiched between the complete GND layer and the power supply layer, which provides a good electrical reference plane for brain electrical signal transmission, effectively guarantees signal integrity, reduces electromagnetic interference of brain electrical signals caused by wire transmission, and helps 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 this application is not limited by the order of the actions described, because according to this 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 this application.

[0078] In the above embodiments, the description of each embodiment has its own focus. 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 this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, 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 devices or units can be electrical or other forms.

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

[0081] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein 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 those skilled in the art, according to the idea of ​​the present application, there may be changes in the specific implementation methods 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 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, wherein the reference electrode comprises a buffer drive circuit and a wet electrode sheet, wherein: The ninth to sixteenth input interfaces of the interface module are respectively connected to the output interfaces of the first to eighth active electrode modules via flexible boards; the first interface of the interface module is connected to the output interface of the buffer drive circuit via a flexible board; the input interface of the buffer drive circuit is connected to the wet electrode sheet via an electrode conductor; the second interface of the interface module is connected to the output interface of the bias drive electrode module via a flexible board, and the flexible board is manufactured using a 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 electroencephalogram (EEG) signals; The reference electrode is used to collect a reference signal of the EEG signal by connecting to the wet electrode sheet at the mastoid process 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-flex 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; The first movable electrode module includes a first movable electrode and a first buffer driving circuit, wherein 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 movable electrode is connected to the first port, the fifth port, the sixth port, and the tenth port of the first gain buffer via the thirty-ninth resistor. The first end of the first electrostatic diode is connected between the port connected to the first movable electrode and the thirty-ninth resistor, and the second end of the first electrostatic diode is grounded. The second port of the first gain buffer is connected to the output interface of the first movable electrode via the thirteenth resistor. The fourth port of the first gain buffer is connected to the output interface of the first movable electrode via the first resistor. The seventh port of the first gain buffer is connected to the output interface of the first movable electrode via the second resistor. The ninth port of the first gain buffer is connected to the output interface of the first movable electrode via 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; The circuit boards corresponding to the reference electrode, the bias drive electrode module, and the first, second, third, fourth, fifth, sixth, seventh, and eighth movable electrode modules are FR4 hard boards; 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, and the +2.5V power layer is arranged adjacent to the bottom layer. The intermediate signal layer is used for signal transmission.

2. The rigid-flex active electrode device according to claim 1, wherein: The first gain buffer is an AD8244 chip, and the first electrostatic diode is an ESD electrostatic diode.

3. The rigid-flex active electrode device according to claim 1 or 2, 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.

4. The rigid-flex active electrode device according to claim 3, wherein: 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. The second end of the thirty-third resistor is the output end of the bias driving electrode module.

5. The rigid-flex active electrode device according to claim 4, wherein: The thirty-third resistor is used to perform impedance matching on the bias driving electrode module.

6. A rigid-flex active electrode device, characterized in that: It comprises a shell and the rigid-flex active electrode device according to any one of claims 1 to 5, wherein the rigid-flex active electrode device is arranged inside the shell.

7. 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 5. 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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