Biosignal measurement device and biosignal measurement system

Abstract

Proposed are a biopotential measurement device, a biopotential measurement system, and a biopotential measurement method which can suppress erroneous determination in determining the quality of a contact state of an electrode and a living body. The biopotential measurement device according to the present technology includes an electrode and a control unit. The electrode measures a biopotential. The control unit determines the quality of a contact state of the electrode and the living body on the basis of a signal amplitude of a specific frequency signal.

Description

Technical Field

[0001] The present technology relates to a biological potential measurement device, a biological potential measurement system, and a biological potential measurement method.

Background Art

[0002] Conventionally, as a biological electric measurement device, there is known one that acquires biological information such as electroencephalogram and electrocardiogram by measuring the contact impedance of an electrode in contact with a user's skin (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional biological potential measurement device, depending on the user's wearing state, it may not be possible to accurately determine whether the contact state between the electrode and the user's skin is good, leading to misjudgment.

[0005] Therefore, in the present disclosure, a biological potential measurement device, a biological potential measurement system, and a biological potential measurement method capable of suppressing misjudgment in determining the quality of the contact state between an electrode and a living body are proposed.

Means for Solving the Problems

[0006] To solve the above problems, a biological potential measurement device according to one aspect of the present technology includes an electrode and a control unit. The electrode measures a biological potential. The control unit determines the quality of the contact state between the electrode and the living body based on the signal amplitude of a signal at a specific frequency.

[0007] The control unit may determine whether the contact state is good or bad based on whether the signal amplitude exceeds a predetermined threshold value.

[0008] The signal of the specific frequency may be a signal caused by a commercial power supply.

[0009] It may further include a reference electrode that provides a reference point for the potential during the potential measurement of the electrode.

[0010] It may further include an amplification circuit that amplifies the potential difference between the potential measured by the electrode and the potential measured by the reference electrode.

[0011] The electrode has a first measurement electrode and a second measurement electrode. The amplification circuit may have a first amplification circuit connected to the first measurement electrode and a second amplification circuit connected to the second measurement electrode.

[0012] When both the signal amplitude of the signal caused by the commercial power supply output from the first amplification circuit and the signal amplitude of the signal caused by the commercial power supply output from the second amplification circuit exceed a predetermined threshold value, the control unit may determine that the contact state between the living body and the reference electrode is poor.

[0013] When either one of the signal amplitude of the signal caused by the commercial power supply output from the first amplification circuit and the signal amplitude of the signal caused by the commercial power supply output from the second amplification circuit does not exceed a predetermined threshold value, the control unit may determine that the contact state between the living body and the reference electrode is good.

[0014] When the signal amplitude of the signal caused by the commercial power supply output from the first amplification circuit exceeds a predetermined threshold value, the control unit may determine that the contact state between the first measurement electrode and the living body is poor and determine that the contact state between the second measurement electrode and the living body is good.

[0015] When the signal amplitude of the signal caused by the commercial power supply output from the first amplification circuit does not exceed a predetermined threshold and the signal amplitude of the signal caused by the commercial power supply output from the second amplification circuit exceeds the predetermined threshold, the control unit may determine that the contact state between the first measurement electrode and the living body is good and determine that the contact state between the second measurement electrode and the living body is bad.

[0016] When neither the signal amplitude of the signal caused by the commercial power supply output from the first amplification circuit nor the signal amplitude of the signal caused by the commercial power supply output from the second amplification circuit exceeds a predetermined threshold, the control unit may determine that the contact states between the first and second measurement electrodes and the living body are good.

[0017] When the control unit determines that the contact state is bad, the control unit may cause a display device to display information for allowing the user to confirm the contact state.

[0018] The bioelectric potential measurement device may be configured to measure electroencephalogram.

[0019] The bioelectric potential measurement device may be configured to measure electrocardiogram.

[0020] To solve the above problems, a bioelectric potential measurement system according to an aspect of the present technology includes a bioelectric potential measurement device and a display device. The bioelectric potential measurement device includes an electrode and a control unit. The electrode measures a bioelectric potential. The control unit determines whether the contact state between the electrode and the living body is good or bad based on the signal amplitude of a signal having a specific frequency. The display device displays the bioelectric potential and the contact state between the electrode and the living body.

[0021] When the control unit determines that the contact state is bad, the display device may display information for allowing the user to confirm the contact state.

[0022] To solve the above problems, a biological potential measurement method of a biological potential measurement device according to an aspect of the present technology is as follows: The biological potential is measured. Based on the signal amplitude of a signal with a specific frequency, whether the contact state between the electrode and the living body is good or bad is determined.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present technology will be described with reference to the drawings.

[0025] <Configuration of the Biological Potential Measurement System> FIG. 1 is a schematic diagram showing a configuration example of the biological potential measurement system 1 of the present embodiment. As shown in FIG. 1, the biological potential measurement system 1 includes a biological potential measurement device 10, an information processing device 30, and a display device 31.

[0026] The biological potential measurement device 10 and the information processing device 30 are connected wirelessly or by wire. Alternatively, the biological potential measurement device 10 and the information processing device 30 may be connected to be communicable with each other via an arbitrary network. In this case, the network may be the Internet, a mobile communication network, a local area network, or the like, or may be a network in which a plurality of these types of networks are combined.

[0027] [Biological potential measurement device] The biological potential measurement device 10 is typically an electroencephalogram headset worn on the user's head. The biological potential measurement device 10 has a plurality of measurement electrodes for measuring biological potentials and a reference electrode (reference electrode) serving as a reference for obtaining a potential difference between the potential measured by the measurement electrodes.

[0028] The biological potential measurement device 10 has an input device (see FIG. 3) for inputting operation information for the user to operate the biological potential measurement system 1, and operation information for realizing a user-desired operation is input.

[0029] The biological potential measurement device 10 measures the biological potential of the user. Information regarding the biological potential measured by the biological potential measurement device 10 is output to the information processing device 30.

[0030] FIG. 2 is a diagram showing a detailed configuration of a main part of the biological potential measurement device 10. The biological potential measurement device 10 has a differential amplification circuit 11, a first measurement electrode 12, a second measurement electrode 13, a reference electrode 14, a bias electrode 15, ADCs 16 and 17, a bus 18, a control unit 19, and a communication module 20. The differential amplification circuit 11 is an example of the "amplification circuit" in the claims.

[0031] As shown in FIG. 2, the differential amplification circuit 11 has amplification circuits 111 and 112 and impedance conversion circuits 113 and 114. The amplification circuit 111 is an amplification circuit that amplifies a biological potential (electroencephalogram) corresponding to the potential difference between the first measurement electrode 12 and the reference electrode 14.

[0032] The positive input terminal of the amplifier circuit 111 is connected to the first measurement electrode 12. The negative input terminal of the amplifier circuit 111 is connected to the output terminal of the impedance conversion circuit 113. The output of the differential amplifier 111 is connected to the ADC 16.

[0033] The amplifier circuit 112 is an amplifier circuit that amplifies the bioelectric potential corresponding to the potential difference between the second measurement electrode 13 and the reference electrode 14. The amplifier circuit 112 measures the potential difference between the second measurement electrode 13 and the reference electrode 14 and amplifies the measured potential difference.

[0034] The positive input terminal of the amplifier circuit 112 is connected to the second measurement electrode 13. The negative input terminal of the amplifier circuit 112 is connected to the output terminal of the amplifier circuit 112. The output of the amplifier circuit 112 is connected to the ADC 17.

[0035] The impedance conversion circuit 113 is a circuit that does not amplify the potential measured by the reference electrode 14 but converts the impedance. The impedance circuit 113 is a circuit called a so-called voltage follower circuit. The positive input terminal of the amplifier circuit 113 is connected to the reference electrode 14. The output of the differential amplifier 113 is connected to the negative input terminals of the differential amplifiers 111 and 112.

[0036] The impedance conversion circuit 114 is a circuit that applies a fixed potential of resistor voltage division connected to the positive input terminal to the living body, and is a circuit called a voltage follower circuit similar to the impedance conversion circuit 113. The impedance conversion circuit 114 can apply a fixed potential to the living body regardless of the impedance between the bioelectric potential measuring device 10 and the living body. The output of the impedance conversion circuit 114 is connected to the bias electrode 15.

[0037] The first and second measurement electrodes 12 and 13 measure the brain waves of the user. The reference electrode 14 is a reference electrode that provides a potential reference point when measuring the bioelectric potential of the first and second measurement electrodes 12 and 13. The bias electrode 15 is an electrode that determines the potential relationship between the bioelectric potential measuring device 10 and the living body.

[0038] The first and second measurement electrodes 12, 13, the reference electrode 14, and the bias electrode 15 are electrodes for acquiring electric potential from a living body. These electrodes 12 to 15 are typically Ag / AgCl electrodes, but are not limited thereto, and may be composed of, for example, gold (Au), stainless steel, or the like. Further, the first and second measurement electrodes 12, 13, the reference electrode 14, and the bias electrode 15 may be gel electrodes, dry electrodes, or wet electrodes.

[0039] ADC 16 is an A / D converter that converts an analog signal of the potential difference amplified by the amplifier circuit 111 into a digital signal and outputs this digital signal to the control unit 19 via the bus 18. Similarly, ADC 17 is an A / D converter that converts an analog signal of the potential difference amplified by the amplifier circuit 112 into a digital signal and outputs this digital signal to the control unit 19 via the bus 18.

[0040] The control unit 19 controls all or part of the operations of the biological potential measurement device 10 according to a program. Specifically, it controls the timing when reading digital values for ADC 16 and ADC 17, and controls various measurement modes. The reading timing is usually performed at fixed intervals. For example, when the measurement frequency of biological potential measurement is 1000 Hz, the readings for ADC 16 and ADC 17 are performed every 1 ms.

[0041] The communication module 20 communicates with the information processing device 30. The communication module 20 functions as a communication interface of the biological potential measurement device 10.

[0042] [Information Processing Device] The information processing device 30 executes predetermined processing on the biological potential signal acquired by the biological potential measurement device 10 and outputs the processing result to the display device 31. The information processing device 30 is connected to the biological potential measurement device 10 by wire or wirelessly.

[0043] The information processing device 30 is typically a desktop PC, but is not limited thereto, and may be any other computer such as a laptop PC.

[0044] [Display device] The display device 31 displays the processing result processed by the information processing device 30. The display device 31 displays the measurement result of the bioelectric potential measured by each measurement electrode in contact with the user's head. Further, the display device 31 displays the mounting state of each measurement electrode in contact with the user's head.

[0045] [Hardware configuration] FIG. 3 is a block diagram showing a hardware configuration example of the bioelectric potential measurement device 10 and the information processing device 30. The bioelectric potential measurement device 10 and the information processing device 30 may be the information processing device 100 shown in FIG. 3.

[0046] The information processing device 100 includes a CPU (Central Processing unit) 101, a ROM (Read Only Memory) 012, and a RAM (Random Access Memory) 103. Further, the information processing device 100 may have a configuration including a host bus 104, a bridge 105, an external bus 106, an interface 107, an input device 108, an output device 109, a storage device 110, a drive 115, a connection port 116, and a communication device 117.

[0047] Furthermore, the information processing device 100 may have a configuration including an imaging device 118 and a sensor 119 as necessary. The information processing device 100 may have a processing circuit such as a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field-Programmable Gate Array) instead of or together with the CPU 101.

[0048] The CPU 101 functions as an arithmetic processing unit and a control unit, and controls all or part of the operations within the information processing apparatus 100 in accordance with various programs recorded in the ROM 102, the RAM 103, the storage device 110, or the removable recording medium 40. The control unit 19 may be the CPU 101.

[0049] The ROM 102 stores programs, arithmetic parameters, etc. used by the CPU 101. The RAM 103 temporarily stores programs used in the execution of the CPU 101 and parameters that change as appropriate during the execution.

[0050] The CPU 101, the ROM 102, and the RAM 103 are interconnected by a host bus 104 formed by an internal bus such as a CPU bus. Further, the host bus 104 is connected to an external bus 106 such as a PCI (Peripheral Component Interconnect / Interface) bus via a bridge 105.

[0051] The input device 108 is a device operated by a user, such as a mouse, a keyboard, a touch panel, buttons, switches, and levers. The input device 108 may be, for example, a remote control device using infrared rays or other radio waves, or an external connection device 50 such as a mobile phone corresponding to the operation of the information processing apparatus 100.

[0052] The input device 108 includes an input control circuit that generates an input signal based on the information input by the user and outputs it to the CPU 101. By operating this input device 108, the user inputs various data to the information processing apparatus 100 and instructs processing operations.

[0053] The output device 109 is composed of devices capable of notifying the acquired information to the user using senses such as vision, hearing, and touch. The output device 109 is, for example, an LCD (Liquid It may be a display device such as a liquid crystal display (LCD) or an organic electroluminescence (EL) display, an audio output device such as a speaker or headphones, or a vibrator, etc.

[0054] The output device 109 outputs the result obtained by the processing of the information processing device 100 as video such as text or images, audio such as voice or sound, or vibration. The display device 31 corresponds to the output device 109.

[0055] The storage device 110 is a data storage device configured as an example of the storage unit of the information processing device 100. The storage device 110 is composed of, for example, a magnetic storage unit device such as a hard disk drive (HDD), a semiconductor storage device, an optical storage device, or a magneto-optical storage device. The storage device 110 stores, for example, programs executed by the CPU 101, various data, and various data acquired from the outside.

[0056] The drive 115 is a reader / writer for a removable recording medium 40 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, and is built in or externally attached to the information processing device 100. The drive 115 reads the information recorded on the mounted removable recording medium 40 and outputs it to the RAM 103. Also, the drive 115 writes a record to the mounted removable recording medium 40.

[0057] The connection port 116 is a port for connecting a device to the information processing apparatus 100. The connection port 116 can be, for example, a USB (Universal Serial Bus) port, an IEEE 1394 port, a SCSI (Small Computer System Interface) port, etc. Also, the connection port 116 may be an RS-232C port, an optical audio terminal, an HDMI (registered trademark) (High-Definition Multimedia Interface) port, etc. By connecting the external connection device 50 to the connection port 116, various data can be exchanged between the information processing apparatus 100 and the external connection device 50.

[0058] The communication device 117 is, for example, a communication interface composed of a communication device for connecting to the communication network N. The communication device 117 can be, for example, a communication card for LAN (Local Area Network), Bluetooth (registered trademark), Wi-Fi, or WUSB (Wireless USB).

[0059] The communication device 117 may also be a router for optical communication, a router for ADSL (Asymmetric Digital Subscriber Line), or a modem for various communications. The communication device 117 transmits and receives signals, etc. using a predetermined protocol such as TCP / IP, for example, between the Internet and other communication devices. The communication module 20 corresponds to the communication device 117.

[0060] Also, the communication network N connected to the communication device 117 is a network connected by wire or wirelessly, and may include, for example, the Internet, a home LAN, infrared communication, radio wave communication, or satellite communication.

[0061] The imaging device 118 is a device that images the real space using various members such as an imaging element such as a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge Coupled Device), and a lens for controlling the imaging of the subject image on the imaging element, and generates an imaging image. The imaging device 118 may capture still images or may also capture moving images.

[0062] The sensor 119 is various sensors such as, for example, an acceleration sensor, an angular velocity sensor, a geomagnetic sensor, an illuminance sensor, a temperature sensor, an atmospheric pressure sensor, or a sound sensor (microphone).

[0063] The sensor 119 acquires information regarding the state of the information processing device 100 itself, such as the posture of the housing of the information processing device 100, and information regarding the surrounding environment of the information processing device 100, such as the brightness and noise around the information processing device 100. Further, the sensor 119 may include a GPS (Global Positioning System) receiver that receives a GPS signal and measures the latitude, longitude, and altitude of the device.

[0064] The configuration example of the bioelectric potential measurement system 1 has been shown above. Each of the above components may be configured using general-purpose members, or may be configured by hardware specialized for the functions of each component. Such a configuration can be appropriately changed according to the technical level at the time of implementation.

[0065] <Electrode Contact State Determination Method> FIG. 4 is a flowchart showing the flow of a typical operation of the bioelectric potential measurement device 10. Hereinafter, a method for determining the quality of the contact state between the user and the electrode will be described with appropriate reference to FIG. 4.

[0066] First, prior to explaining the operation of the bioelectric potential measurement device 10 of the present embodiment, commercial power supply noise will be described.

[0067] In the user whose bioelectric potential is measured by the bioelectric potential measuring device 10, commercial power supply noise in the measured area is propagated. The frequency of the commercial power supply noise is 50 Hz in eastern Japan and 60 Hz in western Japan. The commercial power supply noise in the present embodiment is 50 Hz hum noise, and the same applies to the following description. Around us, in Japan, electrical products operating on a 100V AC power supply are operating everywhere, and commercial power supply noise derived from the 100V AC power supply is propagated to the steel bars of buildings and metal furniture in the room. In such an environment, even if a person is not physically in contact with the building or furniture, the noise is propagated to the human body by capacitive coupling. As a result, commercial power supply noise is observed as common mode noise by the bioelectric potential measuring device 10. At this time, if the contact impedance matching between each measurement electrode 12, 13 and the reference electrode 14 is not achieved, commercial power supply noise remains on the output side of the differential amplifier circuit 11. Therefore, the bioelectric potential measuring device 10 of the present embodiment determines the contact state of the first and second measurement electrodes 12, 13 and the reference electrode 14 based on whether the signal intensity of the commercial power supply noise remaining on the output side of the differential amplifier circuit 11 exceeds a predetermined threshold value. Hereinafter, some patterns of the determination method of the contact state will be described.

[0068] (Pattern 1) FIG. 5 is a diagram showing a detailed configuration of the bioelectric potential measuring device 10, and is a diagram showing a case where the contact state of the reference electrode 14 is poor. The control unit 19 determines whether the signal amplitude of the commercial power supply noise remaining on the output side of the amplifier circuits 111, 112 exceeds a predetermined threshold value (step S101).

[0069] Specifically, when the user's brain waves and commercial power supply noise are superimposed and displayed on the display device 31 and observed as shown in FIG. 6b, the control unit 19 determines whether the signal amplitude D of the commercial power supply noise remaining on the output sides of the amplifier circuits 111 and 112 exceeds a predetermined threshold value. When the signal amplitudes D of all the noises exceed the predetermined threshold value (YES in step S101), the control unit 19 determines that the contact state between the reference electrode 14 and the user is poor (step S102). FIG. 6 is a diagram showing an example of the display screen of the display device 31.

[0070] When the control unit 19 determines that the contact state between the reference electrode 14 and the user is poor, the display device 31 displays information prompting confirmation and improvement of the contact state between the reference electrode 14 and the user. The predetermined threshold value may be arbitrarily set according to the specifications and uses of the biological potential measurement device 10, and the same applies to patterns 2 to 4 described later.

[0071] (Pattern 2) FIG. 7 is a diagram showing a detailed configuration of the biological potential measurement device 10, and shows a case where the contact state of the first measurement electrode 12 is poor and the contact state between the first measurement electrode 12 and the reference electrode 14 is good.

[0072] When none of the signal amplitudes D of the commercial power supply noise remaining on the output sides of the amplifier circuits 111 and 112 exceeds the predetermined threshold value (NO in step S101), the control unit 19 determines that the contact state between the reference electrode 14 and the user is good (step S103).

[0073] Next, the control unit 19 determines whether the signal amplitude D of the commercial power supply noise remaining on the output side of the amplifier circuit 111 exceeds a predetermined threshold value (step S104). Here, when the signal amplitude D exceeds the predetermined threshold value (YES in step S104), the control unit 19 determines that the contact state between the first measurement electrode 12 and the user is poor and determines that the contact state between the second measurement electrode 13 and the user is good (step S105).

[0074] When the contact state between the first measurement electrode 12 and the user is determined by the control unit 19 to be poor, the display device 31 displays information prompting confirmation and improvement of the contact state between the first measurement electrode 12 and the user.

[0075] (Pattern 3) FIG. 8 is a diagram showing a detailed configuration of the bioelectric potential measurement device 10, and shows a case where the contact state between the first measurement electrode 12 and the reference electrode 14 is good and the contact state of the second measurement electrode 13 is poor.

[0076] When the signal amplitude D due to the commercial power supply remaining on the output side of the amplifier circuit 111 does not exceed a predetermined threshold (NO in step S104), the control unit 19 determines whether the signal amplitude D of the commercial power supply noise remaining on the output side of the amplifier circuit 112 exceeds a predetermined threshold (step S106). When the signal amplitude D exceeds the predetermined threshold (YES in step S106), the control unit 19 determines that the contact state between the first measurement electrode 12 and the user is good, and determines that the contact state between the second measurement electrode 13 and the user is poor (step S107).

[0077] When the contact state between the second measurement electrode 13 and the user is determined by the control unit 19 to be poor, the display device 31 displays information prompting confirmation and improvement of the contact state between the second measurement electrode 12 and the user.

[0078] Here, for example, when the control unit 19 determines that the contact state between the first measurement electrode 12 and the user is good, on the display screen of the display device 31, the brain wave measured by the first measurement electrode 12 and the signal due to the commercial power supply whose signal amplitude D is below a predetermined threshold are superimposed and displayed. Alternatively, only the brain wave measured by the first measurement electrode 12 is displayed.

[0079] When only the brain waves measured by the first measurement electrode 12 are displayed on the display screen of the display device 31, the commercial power supply noise input from the first measurement electrode 12 side to the amplifier circuit 111 and the commercial power supply noise input from the reference electrode 14 side to the amplifier circuit 111 cancel each other out. This is because the contact impedance between the first measurement electrode 12 and the reference electrode 14 is matched.

[0080] FIG. 9 is a diagram showing the detailed configuration of the biological potential measurement device 10 and is a diagram for explaining that commercial power supply noise is canceled out.

[0081] When the contact impedance between the first measurement electrode 12 and the reference electrode 14 is matched, the potential measured by the first measurement electrode 12, the potential measured by the reference electrode 14, and the commercial power supply noise are represented by ν eeg , ν ref , ν cmn respectively. Then, the potential P1 observed on the positive electrode side of the amplifier circuit 111 and the potential P2 observed on the negative electrode side of the amplifier circuit 111 are calculated by the following formulas (1) and (2).

[0082] P1 = ν eeg + ν cmn ···(1) P2 = ν ref + ν cmn ···(2)

[0083] Therefore, when the amplifier gain of the amplifier circuit 111 is G, the amplifier circuit 111 outputs a potential P3 calculated by the following formula (3). Therefore, a biological potential without residual commercial power supply noise is obtained, and only the brain waves of the user are displayed on the display screen of the display device 31 as shown in FIG. 6a.

[0084] P3 = G·{(ν eeg + ν cmn ) - (ν ref + ν cmn )} = G·(ν eeg - ν ref )···(3)

[0085] (Pattern 4) When the signal amplitude D of the commercial power supply noise remaining on the output side of the amplifier circuit 112 does not exceed a predetermined threshold value (NO in step S106), the control unit 19 determines that the contact states between the first and second measurement electrodes 12 and 13 and the user are good (step S108).

[0086] <Function and Effect> Conventionally, in a biological potential measurement device that measures brain waves, electrocardiograms, etc., a configuration is known in which the potential difference from each measurement site is obtained via a differential amplifier circuit with reference to a reference potential. In such a configuration, the measurement sites are at two or more channels, and the reference potential is often impedance-converted using a buffer circuit. The signal quality of the biological potential measurement device greatly depends on the wearing state of the user and the electrodes.

[0087] The wearing state of the user and the electrodes can be monitored by measuring the contact impedance between the user and the electrodes at each electrode. An electroencephalograph equipped with such electrodes measures electroencephalograms and contact impedance simultaneously.

[0088] As shown in FIG. 2, when the circuit model of the contact portion between the electrode and the user has a configuration in which a resistance component and a capacitance component are connected in parallel, the contact impedance, the resistance value of the resistance component, the capacitance value of the capacitance component, the angular frequency, the imaginary unit, and the measurement frequency are represented by Z, R1, C1, ω, j, and f, respectively. For example, it is expressed by the following formula (4).

[0089] Z=(R1·1 / jωC1) / (R1+1 / jωC1)=R1 / (1+j·2πfR1C1)··(4)

[0090] Here, in measuring the user's brain waves, the contact impedance in the DC to 60 Hz band is important. However, in order to measure both the brain waves and the contact impedance simultaneously, the brain waves must be measured in a high-frequency band, and accordingly, the contact impedance must also be measured in a high-frequency band. At this time, according to Equation (4), it can be seen that the higher the measurement frequency, the smaller the impedance of the capacitance component, and as a result, the contact impedance becomes smaller.

[0091] Originally, in a bioelectric potential measurement device, in measuring the user's brain waves, the contact impedance is measured to confirm the signal quality. However, depending on the usage situation of the device, there may be no meaning in measuring the contact impedance.

[0092] For example, the electrodes must be in contact with at least the user's scalp in order to measure the brain waves. However, when measuring the contact impedance in a high-frequency band, even if the electrodes merely touch the user's hair, the contact impedance becomes low (the signal amplitude of the contact impedance becomes small), making it difficult to determine whether the signal quality is good or not, and there may be a case of causing a misjudgment.

[0093] On the other hand, the bioelectric potential measurement device 10 of the present embodiment determines the contact state of the electrodes based on whether the signal intensity (signal amplitude) of the commercial power supply noise (hum noise) superimposed on the bioelectric potential waveform exceeds a predetermined threshold value. Thereby, it is possible to accurately determine the quality of the contact state between the user and the electrodes while simultaneously measuring the brain waves and the contact impedance regardless of whether the contact impedance is low or high, that is, regardless of whether the signal amplitude of the contact impedance is small or large.

[0094] Further, according to the bioelectric potential measurement device 10, since the determination index for determining the contact state between the user and the electrodes is the commercial power supply noise, it is possible to determine the quality of the contact state of the electrodes with a simple configuration without separately increasing the number of parts for determining the contact state.

[0095] <Modification Example> The embodiments of the present technology have been described above. However, the present technology is not limited to the above-described embodiments, and it goes without saying that various modifications can be made.

[0096] For example, the amplifier circuits 111 and 112 may be single-stage, or may be cascaded with two or more stages. Further, an analog filter block may be provided, for example, between the amplifier circuits 111 and 112 and the ADCs 16 and 17.

[0097] Also, a plurality of predetermined threshold values in the above embodiment may be set, and the contact state between the user and the electrode may be determined in three stages such as "good", "medium", and "bad" step by step. Further, the determined contact state may be color-coded and displayed by the display device 31, for example, so that the user may be more explicitly urged to improve the contact state.

[0098] Furthermore, the biological potential measurement device 10 in the above embodiment has a configuration having two electrodes (first and second measurement electrodes 12 and 13) for measuring the brain waves of the user, but is not limited thereto, and may have a configuration having one or three or more electrodes.

[0099] <Supplementary Note> The embodiments of the present technology may include, for example, a biological potential measurement device, a biological potential measurement system, a biological potential measurement method executed by the biological potential measurement device or the biological potential measurement system, a program for functioning the biological potential measurement device, and a non-transitory tangible medium on which the program is recorded, as described above.

[0100] Also, in the above embodiment, the description has been made on the premise that the biological potential measurement device measures the brain waves of the user, but is not limited thereto. For example, the present technology may be applied to an electrocardiograph that measures the electrocardiogram of the user, and its use is not particularly limited.

[0101] Furthermore, the effects described in this specification are merely illustrative or exemplary and not restrictive. That is, the present technology may exhibit other effects that are obvious to those skilled in the art from the description of this specification, together with or instead of the above effects.

[0102] The preferred embodiments of the present technology have been described in detail above with reference to the accompanying drawings, but the present technology is not limited to such examples. It is obvious that those having ordinary knowledge in the technical field of the present technology can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and these are also naturally understood to belong to the technical scope of the present technology.

[0103] In addition, the present technology can also have the following configurations.

[0104] (1) An electrode for measuring a bioelectric potential, A control unit that determines the quality of the contact state between the electrode and the living body based on the signal amplitude of a signal of a specific frequency A bioelectric potential measurement device comprising the above. (2) The bioelectric potential measurement device according to (1) above, wherein the control unit determines the quality of the contact state based on whether the signal amplitude exceeds a predetermined threshold value A bioelectric potential measurement device. (3) The bioelectric potential measurement device according to (1) or (2) above, wherein the signal of the specific frequency is a signal caused by a commercial power supply A bioelectric potential measurement device. (4) The bioelectric potential measurement device according to (3) above, further comprising a reference electrode that provides a reference point for the potential during the potential measurement of the electrode A bioelectric potential measurement device. (5) The bioelectric potential measurement device according to (4) above, further comprising an amplification circuit that amplifies the potential difference between the potential measured by the electrode and the potential measured by the reference electrode A bioelectric potential measurement device. (6) The bioelectric potential measurement device according to (5) above, The electrode has a first measurement electrode and a second measurement electrode. The amplifier circuit has a first amplifier circuit connected to the first measurement electrode and a second amplifier circuit connected to the second measurement electrode. Biopotential measurement device. (7) The biopotential measurement device according to (6) above, When both the signal amplitude of the signal caused by the commercial power supply output from the first amplifier circuit and the signal amplitude of the signal caused by the commercial power supply output from the second amplifier circuit exceed a predetermined threshold value, the control unit determines that the contact state between the living body and the reference electrode is poor. Biopotential measurement device. (8) The biopotential measurement device according to (6) or (7) above, When either one of the signal amplitude of the signal caused by the commercial power supply output from the first amplifier circuit and the signal amplitude of the signal caused by the commercial power supply output from the second amplifier circuit does not exceed a predetermined threshold value, the control unit determines that the contact state between the living body and the reference electrode is good. Biopotential measurement device. (9) The biopotential measurement device according to any one of (6) to (8) above, When the signal amplitude of the signal caused by the commercial power supply output from the first amplifier circuit exceeds a predetermined threshold value, the control unit determines that the contact state between the first measurement electrode and the living body is poor, and determines that the contact state between the second measurement electrode and the living body is good. Biopotential measurement device. (10) The biopotential measurement device according to any one of (6) to (9) above, When the signal amplitude of the signal caused by the commercial power supply output from the first amplifier circuit does not exceed a predetermined threshold value and the signal amplitude of the signal caused by the commercial power supply output from the second amplifier circuit exceeds a predetermined threshold value, the control unit determines that the contact state between the first measurement electrode and the living body is good, and determines that the contact state between the second measurement electrode and the living body is poor. Biopotential measurement device. (11) The biopotential measurement device according to any one of (6) to (10), when neither the signal amplitude of the signal caused by the commercial power supply output from the first amplifier circuit nor the signal amplitude of the signal caused by the commercial power supply output from the second amplifier circuit exceeds a predetermined threshold value, the control unit determines that the contact state between the first and second measurement electrodes and the living body is good Biopotential measurement device. (12) The biopotential measurement device according to any one of (1) to (11), when the control unit determines that the contact state is poor, the control unit causes the display device to display information for allowing the user to confirm the contact state Biopotential measurement device. (13) The biopotential measurement device according to any one of (1) to (12), the biopotential measurement device is configured to be able to measure electroencephalogram Biopotential measurement device. (14) The biopotential measurement device according to any one of (1) to (13), the biopotential measurement device is configured to be able to measure electrocardiogram Biopotential measurement device. (15) electrodes for measuring biopotentials, a control unit that determines whether the contact state between the electrodes and the living body is good or bad based on the signal amplitude of a signal having a specific frequency, and a biopotential measurement device having the above, a display device that displays the biopotential and the contact state between the electrodes and the living body, and a biopotential measurement system including the above. (16) The biopotential measurement system according to (15), when the contact state is determined to be poor by the control unit, the display device displays information for allowing the user to confirm the contact state Biopotential measurement system. (17) The biopotential measurement device measures the biopotential, and determines the quality of the contact state between the electrode and the living body based on the signal amplitude of a signal of a specific frequency. Biopotential measurement method.

Explanation of symbols

[0105] Biopotential measurement system... 1 Biopotential measurement device... 10 Differential amplifier circuit (amplifier circuit)... 11 First measurement electrode... 12 Second measurement electrode... 13 Reference electrode... 14 ADC... 16, 17 Control unit... 19 Information processing device... 30, 100 Display device... 31 Amplifier circuit... 111 (first amplifier circuit), 112 (second amplifier circuit) Impedance conversion circuit... 113, 114

Claims

1. An electrode for measuring a bioelectric potential, A reference electrode that provides a reference point for potential during potential measurement of the electrode, An amplifier circuit that amplifies the potential difference between the potential measured by the electrode and the potential measured by the reference electrode, A control unit that determines the quality of the contact state between the electrode and the living body based on the signal amplitude of a signal of a specific frequency superimposed on the bioelectric potential while simultaneously measuring the bioelectric potential and the contact impedance between the electrode and the living body, Comprising: The signal of the specific frequency is a signal caused by a commercial power supply, The electrode has a first measurement electrode and a second measurement electrode, The amplifier circuit has a first amplifier circuit connected to the first measurement electrode and a second amplifier circuit connected to the second measurement electrode, When the signal amplitude of the signal caused by the commercial power supply output from the first amplifier circuit and superimposed on the bioelectric potential does not exceed a predetermined threshold value, and the signal amplitude of the signal caused by the commercial power supply output from the second amplifier circuit and superimposed on the bioelectric potential exceeds the predetermined threshold value, the control unit determines that the contact state between the first measurement electrode and the living body is good and determines that the contact state between the second measurement electrode and the living body is bad. A bioelectric potential measurement device.

2. The bioelectric potential measurement device according to claim 1, When the signal amplitudes of the signals caused by the commercial power supply output from the first amplifier circuit and superimposed on the bioelectric potential and the signal amplitudes of the signals caused by the commercial power supply output from the second amplifier circuit and superimposed on the bioelectric potential do not exceed a predetermined threshold value, the control unit determines that the contact states of the first and second measurement electrodes with the living body are good. A bioelectric potential measurement device.

3. The bioelectric potential measurement device according to claim 1, When the control unit determines that the contact state is bad, it causes a display device to display information for allowing the user to confirm the contact state. A bioelectric potential measurement device.

4. The bioelectric potential measurement device according to claim 1, The bioelectric potential measurement device is configured to be able to measure electroencephalogram. A bioelectric potential measurement device.

5. The bioelectric potential measurement device according to claim 1, The bioelectric potential measurement device is configured to be able to measure electrocardiogram. A bioelectric potential measurement device.

6. An electrode for measuring a bioelectric potential, A reference electrode that provides a reference point for potential during potential measurement of the electrode, An amplifier circuit that amplifies the potential difference between the potential measured by the electrode and the potential measured by the reference electrode, A control unit that determines the quality of the contact state between the electrode and the living body based on the signal amplitude of a signal of a specific frequency superimposed on the bioelectric potential while simultaneously measuring the bioelectric potential and the contact impedance between the electrode and the living body A bioelectric potential measuring device having the same A display device that displays the bioelectric potential and the contact state between the electrode and the living body Comprising The signal of the specific frequency is a signal caused by a commercial power supply The electrode has a first measurement electrode and a second measurement electrode The amplification circuit has a first amplification circuit connected to the first measurement electrode and a second amplification circuit connected to the second measurement electrode When the signal amplitude of the signal caused by the commercial power supply output from the first amplification circuit and superimposed on the bioelectric potential does not exceed a predetermined threshold value, and the signal amplitude of the signal caused by the commercial power supply output from the second amplification circuit and superimposed on the bioelectric potential exceeds the predetermined threshold value, the control unit determines that the contact state between the first measurement electrode and the living body is good, and determines that the contact state between the second measurement electrode and the living body is bad A bioelectric potential measurement system

7. The bioelectric potential measurement system according to claim 6, wherein When the control unit determines that the contact state is bad, the display device displays information for allowing the user to confirm the contact state A bioelectric potential measurement system

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