WO2019003653A1

WO2019003653A1 - Biopotential measurement device, electrostatic capacitance control device, electroencephalograph, electrostatic capacitance control method, and program

Info

Publication number: WO2019003653A1
Application number: PCT/JP2018/018025
Authority: WO
Inventors: 秋憲松本
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-06-30
Filing date: 2018-05-10
Publication date: 2019-01-03
Also published as: JPWO2019003653A1; JP6909968B2

Abstract

A biopotential measurement device (1b) is for measuring the biopotential of a user (10). The biopotential measurement device (1b) is provided with: a biopotential amplification unit (14) that differentially amplifies a biopotential detected by a reference electrode (49) and a measurement electrode (48) brought into contact with the user (10), and performs A/D conversion thereon; a biopotential output unit (15) that outputs the biopotential converted into a digital signal; a power supply unit (220) that supplies electric power to the biopotential amplification unit (14) and/or the biopotential output unit (15); and an electrostatic capacitance (201) equipped with a capacitance electrode to which a wire as a shield member (200) covering the perimeter of the measurement electrode (48) is connected. The ground potential of the power supply unit (220) is electrically connected to the ground potential of the electrostatic capacitance (201).

Description

Biopotential measurement device, capacitance control device, electroencephalograph, capacitance control method and program

The present disclosure relates to a bioelectric potential measurement device, a capacitance control device, an electroencephalograph, a capacitance control method, and a program.

Conventionally, there is a bioelectric potential measuring device for measuring bioelectric potentials such as electroencephalograms and electrocardiograms of a living body. In the biopotential measurement apparatus, for example, the user wears an electrode (bioelectrode) on the skin and acquires biopotentials such as electroencephalograms and electrocardiograms as bioinformation. In addition, depending on the bioelectric potential measurement device, an output unit that outputs the acquired biological information to an external device by wireless may be provided. For example, Patent Document 1 discloses a medical telemeter which outputs acquired biological information by radio.

JP-A-5-192304

However, in the technique described in Patent Document 1, when wireless communication is performed, current consumption is instantaneously increased depending on the communication status, thereby deteriorating the signal quality of the output biological information, interrupting wireless communication, etc. And there is a problem that stable measurement can not be performed.

The present disclosure has been made in view of the above problems, and when performing biopotential measurement using wireless communication, it is possible to measure biopotential with stable signal quality with less power fluctuation, instantaneous blackouts, etc. It is an object of the present invention to provide a bioelectric potential measuring device etc.

A biopotential measuring device according to an aspect of the present disclosure is a biopotential measuring device for measuring a biopotential, which comprises a measuring electrode in contact with a living body, and a biopotential for amplifying the biopotential detected by the measuring electrode. An amplification unit, a biopotential output unit for outputting the biopotential amplified by the biopotential amplification unit, a power supply unit for supplying power to at least one of the biopotential amplification unit and the biopotential output unit, and the measurement electrode And a capacitance having a capacitance electrode connected to a wire covering the periphery of the shield as a shield member, wherein the ground potential of the power supply unit is electrically connected to the ground potential of the capacitance.

Further, a capacitance control device according to an aspect of the present disclosure is a capacitance control device for controlling a plurality of capacitances included in a biopotential measurement device for measuring a biopotential, the biopotential measurement The apparatus comprises: a measurement electrode in contact with a living body; a biopotential amplification unit for amplifying the biopotential detected by the measurement electrode; and a biopotential output unit for outputting the biopotential amplified by the biopotential amplification unit. The capacitance control device includes: a plurality of capacitances each having a capacitance electrode connected to a wiring that covers the periphery of the measurement electrode as a shield member; and a power supply unit that receives supply of power from the capacitance. A capacitance control unit is provided for changing the sum of capacitance values of the plurality of capacitances in the biopotential measurement device in which the ground potential of the power supply unit is electrically connected to the ground potential of the capacitance. .

An electroencephalograph according to an aspect of the present disclosure includes the bioelectric potential measurement device and a mounting unit attached to a head of a living body whose biological potential is to be measured, and the measurement electrode is a biological potential of the living body. In order to be in contact with the head of the living body.

Further, a capacitance control method according to an aspect of the present disclosure is a capacitance control method of a plurality of capacitances included in a biopotential measurement device for measuring a biopotential, wherein the biopotential measurement device is a living body A biopotential amplification unit for amplifying the biopotential detected by the measurement electrode, a biopotential output unit for outputting the biopotential amplified by the biopotential amplification unit, and And a power supply unit receiving supply of electric power from the capacitance, the ground potential of the power supply unit is the capacitance of the capacitance. The capacitance control method is electrically connected to the ground potential, and the capacitance control method includes a determination step of determining whether the power supply unit is in the on state or the off state, and the state determined in the determination step. And the plurality of And a control step of changing the total capacitance value of the capacitance.

Further, one aspect of the present disclosure can be realized as a program for causing a computer to function the above-described capacitance control method. Alternatively, it may be realized as a computer readable recording medium storing the program.

According to the bioelectric potential measurement device and the like of the present disclosure, a bioelectric potential measurement device and the like that can perform bioelectric potential measurement of stable signal quality can be provided.

FIG. 1 is a view showing a usage scene of the electroencephalograph according to the embodiment. FIG. 2A is a schematic view showing an example of the electroencephalograph according to the embodiment. FIG. 2B is a schematic view showing another example of the electroencephalograph according to the embodiment. FIG. 3A is a schematic view showing a first example of the shape of an electrode. FIG. 3B is a schematic view showing a second example of the shape of the electrode. FIG. 3C is a schematic view showing a third example of the shape of the electrode. FIG. 3D is a schematic view showing a fourth example of the shape of the electrode. FIG. 3E is a schematic view showing a fifth example of the shape of the electrode. FIG. 4 is a block diagram showing an overall configuration of a system including the bioelectric potential measurement device according to the embodiment. FIG. 5 is a block diagram showing a detailed configuration of a system including the bioelectric potential measurement device according to the embodiment. FIG. 6 is a block diagram showing a hardware configuration of a system including the bioelectric potential measurement device according to the embodiment. FIG. 7 is a block diagram showing the hardware configuration of the information processing apparatus according to the embodiment. FIG. 8 is a flowchart showing a basic processing procedure of the bioelectric potential measuring device and the information processing device according to the embodiment. FIG. 9 is a perspective view showing a detailed configuration of the electroencephalograph provided with the bioelectric potential measurement device according to the embodiment. FIG. 10 is a block diagram showing a detailed configuration when the electroencephalograph according to the embodiment measures a bioelectric potential. FIG. 11 is a block diagram for explaining a circuit configuration of a plurality of capacitances provided in the electroencephalograph according to the embodiment. FIG. 12 is a diagram for explaining an example of the relationship between the operation state of the electroencephalograph and the total capacitance value of the electrostatic capacitance according to the embodiment. FIG. 13 is a timing chart for explaining an example of the relationship between the operation state of the electroencephalograph according to the embodiment and the total capacitance value of the capacitance according to time. FIG. 14 is a flowchart for describing control for changing the total capacitance value of the electrostatic capacitance in accordance with the operation state of the electroencephalograph according to the embodiment. FIG. 15 is a diagram showing input noise of the electroencephalograph according to the embodiment and the electroencephalograph according to the comparative example. FIG. 16 is a flowchart for explaining application processing that is changed according to the operation state of the electroencephalograph according to the embodiment. FIG. 17 is a diagram illustrating a first example of an image displayed by the display unit according to the operation state of the electroencephalograph according to the embodiment. FIG. 18 is a diagram illustrating a second example of an image displayed by the display unit according to the operation state of the electroencephalograph according to the embodiment. FIG. 19 is a diagram illustrating a third example of an image displayed by the display unit according to the operation state of the electroencephalograph according to the embodiment.

Hereinafter, a bioelectric potential measurement apparatus and the like according to the embodiment will be described with reference to the drawings. Note that all the embodiments described below show general or specific examples. Numerical values, shapes, materials, components, arrangement positions of components, connection configurations, steps and order of steps, and the like described in the following embodiments are merely examples, and are not intended to limit the present disclosure. Further, among the components in the following embodiments, components not described in the independent claim indicating the highest concept are described as arbitrary components.

Each figure is a schematic view, and is not necessarily illustrated strictly. Further, in the drawings, substantially the same configurations are denoted by the same reference numerals, and overlapping descriptions may be omitted or simplified.

Embodiment
[Outline of bioelectric potential measurement system]
FIG. 1 is a view showing a usage scene of the electroencephalograph according to the embodiment.

A bioelectric potential measurement system 100 shown in FIG. 1 includes an electroencephalograph 1, an information processing device 2, and a display unit 3. The electroencephalograph 1, the information processing device 2, and the display unit 3 are communicably connected by wire or wireless, respectively, and mutually output (transmit) and / or acquire (receive) information.

The electroencephalograph 1 is a device including the bioelectric potential measurement device 1b (see FIG. 5) according to the embodiment, and is a device for measuring an electroencephalogram that is an example of the bioelectric potential of the user 10. In the present embodiment, the electroencephalograph 1 is a headset-type electroencephalograph that measures the electroencephalogram of the user 10. The electroencephalograph 1 includes a mounting unit 150 for the user 10 to wear on the head, and a plurality of electrodes (electrodes for measuring biopotential) 51 (for example, see FIG. 2A) for measuring the biopotential of the user 10 Prepare.

The plurality of electrodes 51 are in contact with the user 10 when measuring the biopotential. The plurality of electrodes 51 include a measurement electrode 48 (see FIG. 6) for measuring the biopotential, and a reference electrode 49 (see FIG. 6) used to calculate the difference between the potential measured by the measurement electrode 48. The electroencephalograph 1 further includes an operation input device 1a (see FIG. 5) for inputting operation information for the user 10 to operate the bioelectric potential measurement system 100, and an operation for achieving a desired process is input. .

The information processing apparatus 2 acquires operation input data from the electroencephalograph 1 and performs predetermined processing. For example, the information processing device 2 is a personal computer (Personal Computer / PC). The predetermined process is, for example, a process of causing the display unit 3 to display data acquired from the electroencephalograph 1.

The display unit 3 is a display device that displays the processing result performed by the information processing device 2. The display unit 3 is, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, or the like. The display unit 3 displays, for example, the image information acquired from the information processing device 2. The display unit 3 may include a speaker that outputs the acoustic information acquired from the information processing device 2.

[Configuration of electroencephalograph]
FIG. 2A is a schematic view showing an example of the electroencephalograph according to the embodiment. FIG. 2B is a schematic view showing another example of the electroencephalograph according to the embodiment.

For example, the user 10 wears the electroencephalograph 1 on the head. An example of the appearance of the electroencephalograph 1 is a headphone (headset) type in FIG. 2A and a band type in FIG. 2B.

The electroencephalograph 1 shown in FIG. 2A is of an arched headphone type along the head of the user 10. The headphone type electroencephalograph 1 shown in FIG. 2A includes a plurality of electrodes 51, an outer side surface 44, a mounting surface 45, a mounting portion 150, and an operation surface 43. The mounting unit 150 has an arched arm 151 and ear pads 46 attached to both ends of the arm 151 in the electroencephalograph 1 shown in FIG. 2A. The outer side surface 44 is a surface disposed on the opposite side of the head of the user 10 when the user 10 wears the electroencephalograph 1. The mounting surface 45 is a surface disposed on the head side of the user 10 when the user 10 wears the electroencephalograph 1. An operation button 41 and a display device 47 are disposed on the operation surface 43.

The plurality of electrodes 51 are provided on the mounting surface 45 of the electroencephalograph 1 and the end of the ear pad 46 on the same side as the mounting surface 45 of the electroencephalograph 1.

Before wearing the electroencephalograph 1, the user 10 operates the operation button 41 disposed on the operation surface 43 to activate the electroencephalograph 1 and wears the electroencephalograph 1 on the head of the user 10. In the electroencephalograph 1, for example, the left ear pad 46 is positioned at the right ear of the user 10 toward the paper surface of FIG. 2A, and the right ear pad 46 is positioned at the left ear of the user 10 toward the paper surface of FIG. Is mounted on the head of the user 10. Also, the ear pads 46 are applied to cover the left and right ears of the user 10.

The electrode 51 provided on the mounting surface 45 is applied to the skin (scalp) of the user 10. An electrode 51 provided at the end of the earpiece 46 is placed behind the ear of the user 10. For example, the electrode 51 provided at the end of the left ear pad 46 toward the paper surface of FIG. 2A is provided at the end of the right ear pad 46 toward the paper surface of FIG. 2A (see FIG. 6). The other electrode 51 may be used as the measuring electrode 48. The ground electrode 73 c is an electrode for applying a reference potential (also referred to as body ground or ground) at which the electroencephalograph 1 operates in the user 10.

The arrangement position of the ground electrode 73c and the reference electrode 49 is not limited to this, and the electrode 51 provided at the end of the right ear pad 46 toward the paper surface of FIG. 2A is the ground electrode 73c. The electrode 51 provided at the end of the left ear pad 46 may be used as the reference electrode 49.

The display device 47 is, for example, a liquid crystal display or an organic EL display, and displays a state of operation of the operation button 41 of the user 10 or the like.

The electroencephalograph 1001 shown in FIG. 2B is in the form of a band that is worn by being wound around the head of the user 10. A band type electroencephalograph 1001 shown in FIG. 2B includes a plurality of electrodes 51, an outer side surface 44, a mounting surface 45, a mounting portion 150, and an operation surface 43. In the electroencephalograph 1001 shown in FIG. 2B, the mounting unit 150 has a band shape without ear pads. The configuration of the electrode 51, the operation button 41 disposed on the operation surface 43, and the display device 47 is the same as that of the headphone type electroencephalograph 1. Before the user 10 wears the electroencephalograph 1001, the electroencephalograph 1 is activated by operating the operation button 41 disposed on the operation surface 43, and the half of the outer surface 44 of the band type electroencephalograph 1001 (the operation surface 43). Side) is worn so as to come to the forehead of the user 10.

Among the plurality of electrodes 51, the electrode 51 corresponding to the ground electrode 73c and the electrode 51 corresponding to the reference electrode 49 extend a lead wire (not shown) from the mounting surface 45 to the back of the ear of the user 10. It may be a configuration to apply.

[Electrode shape]
3A to 3E show examples of the shape of the contact surface of the electrode 51 in contact with the skin of the user 10. FIG.

The material of the electrode (bioelectrode) 51 is made of a conductive substance. The material of the electrode 51 may be silver-silver chloride (Ag / AgCl) or silver which has less polarization when in contact with a living body and stable polarization voltage.

The shape of the contact surface of the electrode 51 may be circular (for example, 10 mm in diameter) shown in FIG. 3A, similar to an electrode used for medical use. Further, the shape of the contact surface of the electrode 51 may be various shapes depending on the application other than the electrode 51 having a circular contact surface with the living body. For example, it may be a triangle as shown in FIG. 3B, a square as shown in FIG. 3C, or a square.

Further, as shown in (a) and (b) of FIG. 3D, the electrode 51 may be an electrode configured by a plurality of cylinders (five in FIG. 3D). According to such a configuration, since the electrode 51 is in contact with the skin of the user 10, the hair of the user 10 can be scraped off.

In addition, the contact surface with the skin in each cylinder may be circular as shown to (a) of FIG. 3D, and other shapes, such as an ellipse, may be sufficient as it. Moreover, not only a cylinder but a prism may be sufficient. The number of cylinders or prisms may be five as shown in (a) and (b) of FIG. 3D, or may be any number, and is not particularly limited.

Also, the tips of the individual cylinders in FIG. 3D may have a shape in which the corners are in contact with the skin. This can increase the contact area with the skin.

Further, as shown in (a) of FIG. 3E, the shape of the electrode 51 may be such that the contact surface with the skin of the user 10 is concentric. The electrode 51 having such a shape is used, for example, as an electrode provided on the ear pad 46 of the headphone type electroencephalograph 1 shown in FIG. 2A or an electrode provided on the band type electroencephalograph 1001 shown in FIG. It is touched by the place without hair, such as the forehead of 10 and the back of the ear. By doing this, the pressure on the skin is relieved in comparison with the electrode 51 of the shape shown in (a) and (b) of FIG. 3D in the electrode 51 of the shape shown in (a) and (b) of FIG. . Therefore, according to the

electroencephalographs

1 and 1001 provided with the electrode 51 having the above-mentioned shape, it is possible to ease the burden that the user 10 receives.

[Configuration of bioelectric potential measurement system]
Next, the configuration of the bioelectric potential measurement system 100 will be described. FIG. 4 is a block diagram showing an overall configuration of a system including the bioelectric potential measurement device 1b according to the embodiment.

The bioelectric potential measurement system 100 includes an electroencephalograph 1, an information processing device 2, and a display unit 3. The electroencephalograph 1 includes an operation input device 1a and a bioelectric potential measurement device 1b.

The electroencephalograph 1 acquires information input to the user 10 by the operation input device 1a, and measures the biopotential of the user 10 by the biopotential measuring device 1b. The bioelectric potential measured by the electroencephalograph 1 is output (sent) to the information processing device 2.

The information processing device 2 receives an input from the operation input device 1a and / or the bioelectric potential measurement device 1b, performs a predetermined process, and outputs the processing result to the display unit 3.

FIG. 5 is a block diagram showing the detailed configurations of the electroencephalograph 1 and the information processing apparatus 2. Here, the case where the electroencephalograph 1 and the information processing device 2 are connected wirelessly will be described as an example.

The operation input device 1 a of the electroencephalograph 1 includes an operation input unit 11 and an operation signal output unit 12.

The operation input unit 11 is a processing unit that acquires operation input information input by the operation button 41 (see FIGS. 2A and 2B) and determines the content of the operation. The operation signal output unit 12 is a communication interface for outputting the operation input information acquired by the operation input unit 11 to the information processing device 2. The operation input information acquired by the operation input unit 11 is output from the operation signal output unit 12 to the information processing device 2.

The bioelectric potential measurement device 1b included in the electroencephalograph 1 includes an electrode unit 13, a bioelectric potential amplification unit 14, a bioelectric potential output unit 15, a power supply unit 220, one or more electrostatic capacitances 201, and electrostatic capacitance control And a unit 210a.

The electrode unit 13 is composed of a plurality of electrodes 51. As described above, the plurality of electrodes 51 includes the measurement electrode 48, the reference electrode 49, and the ground electrode 73c. The plurality of electrodes 51 are disposed, for example, at positions in contact with the skin of the user 10 in the electroencephalograph 1.

The biopotential amplification unit 14 is an amplifier that amplifies a biopotential corresponding to the potential difference between the plurality of electrodes 51. Specifically, the biopotential amplification unit 14 measures the potential difference between the measurement electrode 48 and the reference electrode 49, and amplifies the measured potential difference. The amplified potential difference is converted into a digital signal by, for example, an A / D converter (Analog-to-Digital Converter) 75 (see FIG. 6) provided in the biopotential amplification unit 14.

The biopotential amplification unit 14 does not have to amplify the biopotential when it can measure the biopotential having a predetermined potential level or more, and may measure only the potentials of the plurality of electrodes 51.

The biopotential output unit 15 is a communication interface for outputting the potential difference amplified by the biopotential amplification unit 14 to the information processing device 2. The potential difference of the biopotential converted into the digital value in the biopotential amplification unit 14 is output from the biopotential output unit 15 to the information processing device 2.

The power supply unit 220 is a power supply circuit that supplies power to each component of the electroencephalograph 1 such as the biopotential amplification unit 14, the biopotential output unit 15, and the capacitance 201.

The electrostatic capacitance 201 is a capacitor that is connected to the battery 81 and temporarily stores the power supplied to the power supply unit 220. The capacitance 201 is arranged to cover at least the periphery of the measurement electrode 48. In this way, the capacitance 201 functions to prevent extraneous noise that can be received by the measurement electrode 48. As the capacitance 201, for example, an electric double layer capacitance (supercapacitor or ultracapacitor) may be adopted from the viewpoint of making the mounting portion 150 flexible and lightening. The capacitance 201 may be a lithium ion capacitor having the features of both the capacitance and the battery. When the user 10 wears the electroencephalograph 1, the compression of the temples of the user 10 is reduced and the pain of the user 10 is alleviated by making the mounting unit 150 worn by the user 10 in the electroencephalograph 1 flexible and lightweight. And the effect of preventing the mixing of pulse waves is expected.

Further, the ground potential of the power supply unit 220 is electrically connected to the ground potential of the electrostatic capacitance 201. That is, the ground potentials of the power supply unit 220 and the electrostatic capacitance 201 are set to be equal.

The capacitance control unit 210 a is a processing unit that changes the sum of capacitance values (capacitance values) of the plurality of capacitances 201. For example, the capacitance control unit 210a changes the sum of capacitance values (capacitance values) of the plurality of capacitances 201 in accordance with the operation mode of the bioelectric potential output unit 15. As the operation mode, for example, a normal mode and a high speed mode in which the amount of data (communication amount) per unit time of the data of the biopotential output from the biopotential output unit 15 are different are set. Specifically, the capacitance control unit 210a detects the bioelectric potential at the measurement electrode 48, and outputs the detected bioelectric potential to the bioelectric potential output unit 15, and detects the bioelectric potential at the measurement electrode 48. The mode control is performed to switch the detected biopotential to a high-speed mode in which the biopotential output unit 15 outputs the data amount of the biopotential output per unit time more than in the normal mode. In this case, the capacitance control unit 210a performs control to increase the sum of the capacitance values of the plurality of capacitances 201 in the high-speed mode than in the normal mode.

Also, for example, the capacitance control unit 210a changes the sum of the capacitance values of the plurality of capacitances 201 between when the power of the power supply unit 220 is turned on and when the power of the power supply unit 220 is turned off.

Also, for example, when the bioelectric potential output unit 15 outputs the biological potential of the user 10, the electrostatic capacity control unit 210a changes the sum of the capacitance values of the plurality of electrostatic capacitances 201.

A detailed specific example of control of the capacitance value of the capacitance 201 performed by the capacitance control unit 210a will be described later.

The information processing apparatus 2 includes an operation signal acquisition unit 21, a bioelectric potential acquisition unit 22, a bioelectric potential processing unit 23, an application processing unit (application processing unit) 26, a display information output unit 27, and an acoustic information output unit 28. And have.

The information processing apparatus 2 acquires (receives) the operation input information output from the electroencephalograph 1 at the operation signal acquisition unit 21 and acquires the bioelectric potential at the bioelectric potential acquisition unit 22 to obtain information from the electroencephalograph 1. get.

Biopotentials often can not be used as information in original signals that have only been recorded. Therefore, the bioelectric potential processing unit 23 performs processing of extracting meaningful information from the acquired original signal. For example, in the case of electroencephalogram measurement, the signal is limited to signals in a band (frequency of 0.5 Hz to 100 Hz) including a specific frequency (for example, 10 Hz), and Fast Fourier Transform (FFT) is performed. Calculate Power Spectral Density of the signal.

The bioelectric potential processing unit 23 may be disposed in the electroencephalograph 1 instead of the information processing device 2.

The application processing unit 26 performs central application processing (application processing) of the information processing apparatus 2. The application processing is realized by receiving a signal from the electroencephalograph 1 and performing predetermined processing.

The result processed by the application processing unit 26 is output from the application processing unit 26 to the display information output unit 27 and / or the acoustic information output unit 28.

The display information output unit 27 and the acoustic information output unit 28 output a signal serving as visual and / or auditory information to the display unit 3 in order to feed back the result processed by the application processing unit 26 to the user 10. Interface for

[Hardware configuration]
FIG. 6 is a block diagram showing a hardware configuration of a system including the bioelectric potential measurement device 1b according to the embodiment. Specifically, FIG. 6 is a block diagram showing the hardware configuration of the electroencephalograph 1.

The electroencephalograph 1 includes an operation button group 71, a control signal conversion circuit 72, a measurement electrode 48, a reference electrode 49, an earth electrode 73c, a biological amplifier 74, an A / D converter 75, and a transmission circuit 79. A signal processing unit 78, an antenna 68, a power supply unit 220, a battery 81, a capacitance control device 210, and a shield member 200 are provided. The components included in the electroencephalograph 1 are connected to one another by a bus 105 so that data can be transmitted and received mutually.

The operation button group 71 and the control signal conversion circuit 72 correspond to the operation input unit 11 shown in FIG. Further, each button in the operation button group 71 corresponds to the operation button 41. The measurement electrode 48, the reference electrode 49, and the ground electrode 73c correspond to the electrode 51 shown in FIGS. 2A and 2B and the electrode portion 13 shown in FIG. The living body amplifier 74 and the A / D converter 75 correspond to the living body potential amplification unit 14 shown in FIG. Further, the transmission circuit 79 and the antenna 68 function as the biopotential output unit 15 and / or the operation signal output unit 12 shown in FIG.

The battery 81 is a battery for supplying power to the electroencephalograph 1. The battery employed for the battery 81 may be a dry cell, a button cell, a lithium polymer rechargeable battery, a nickel hydrogen rechargeable battery, or the like. The power supply unit 220 converts the voltage supplied from the battery into a desired power supply voltage and supplies the power supply voltage to each component of the electroencephalograph 1.

The signal processing unit 78 includes a CPU (Central Processing Unit) 101, a RAM (Random Access Memory) 102 storing a program 103 which is a control program executed by each component of the electroencephalograph 1, and a ROM (Read Only Memory). And 104). The program 103 describes the signal processing procedure in the electroencephalograph 1. The electroencephalograph 1 converts the operation signal and the biological signal into digital signals according to the program 103 by the CPU, and outputs the digital signals from the antenna 68 to the information processing apparatus 2 via the transmission circuit 79.

The capacitance control device 210 includes the above-described capacitance control unit 210a. The capacitance control unit 210a includes, for example, a CPU 211, a RAM 212 storing a program 213 which is a control program to be executed by the CPU 211, and a ROM 214.

The shield member 200 is provided in the electroencephalograph 1 in order to prevent the measurement electrode 48 from extraneous noise, and includes the one or more capacitances 201 described above.

The depression information of each button regarding the operation button group 71 is converted into a control signal for controlling the operation of the electroencephalograph 1 in the control signal conversion circuit 72, and is output to the CPU 101 via the bus 105.

The measurement electrode 48, the reference electrode 49, and the earth electrode 73c are connected to the living body amplifier 74. These electrodes are installed at predetermined places of the electroencephalograph 1. The potential difference between the measurement electrode 48 and the reference electrode 49 is amplified by the biological amplifier 74 and converted by the A / D converter 75 from an analog biological signal to a digital biological signal. The potential difference converted into the digital biomedical signal is output to the CPU 101 via the bus 105 as a biomedical signal capable of processing and outputting.

The program 103 may be stored in the ROM 104. The signal processing unit 78, the control signal conversion circuit 72, the transmission circuit 79, the living body amplifier 74, and the A / D converter 75 are hardware such as DSP (Digital Signal Processor) in which a computer program is incorporated in one semiconductor integrated circuit. May be realized as By mounting on one semiconductor integrated circuit, the mounting area can be reduced and the power consumption can be reduced. In addition, the biological amplifier 74 and the A / D converter 75 are integrated in one semiconductor integrated circuit, the signal processing unit 78, the control signal conversion circuit 72, and the transmitting circuit 79 are integrated in another semiconductor integrated circuit. The integrated circuits may be connected in one package and integrated as a system-in-package (SiP), and may be realized as hardware such as a DSP incorporating a computer program. By realizing the two semiconductor integrated circuits in separate manufacturing processes, an effect of reducing the cost can be obtained as compared with one mounted on one semiconductor integrated circuit.

FIG. 7 is a block diagram showing the hardware configuration of the information processing apparatus 2 according to the embodiment.

The information processing apparatus 2 includes an antenna 80, a receiving circuit 82, a signal processing unit 108, an image control circuit 84, a display information output circuit 85, an acoustic control circuit 86, an acoustic information output circuit 87, and a power supply 88. Is equipped. The antenna 80 and the receiving circuit 82 correspond to the bioelectric potential acquisition unit 22 and / or the operation signal acquisition unit 21 illustrated in FIG. 5.

The signal processing unit 108 includes a CPU 111, a RAM 112, a program 113 executed by the CPU 111, and a ROM 114. The signal processing unit 108 corresponds to the bioelectric potential processing unit 23 and / or the application processing unit 26 illustrated in FIG. 5. Further, the image control circuit 84 and the display information output circuit 85 correspond to the display information output unit 27 shown in FIG. The sound control circuit 86 and the sound information output circuit 87 correspond to the sound information output unit 28 shown in FIG. In addition, these components are connected to one another by a bus 115, and data can be transmitted and received mutually. Further, power is supplied from the power supply 88 to each component.

The operation information and bioelectric potential output from the electroencephalograph 1 are acquired by the receiving circuit 82 via the antenna 80, and are sent to the CPU 111 via the bus 115.

The CPU 111 is a processing unit that executes the program 113 stored in the RAM 112. The program 113 describes the signal processing procedure in the information processing device 2. The information processing apparatus 2 converts the operation signal and the biological signal according to the program 113, performs processing for executing a predetermined application (program), and transmits a signal for performing feedback to the user 10 by an image and / or sound. Generate The program 113 may be stored in the ROM 114.

The feedback signal of the image generated by the signal processing unit 108 is output from the display information output circuit 85 to the display unit 3 via the image control circuit 84. Similarly, the acoustic feedback signal generated by the signal processing unit 108 is output from the acoustic information output circuit 87 via the acoustic control circuit 86.

The signal processing unit 108, the receiving circuit 82, the image control circuit 84, and the sound control circuit 86 may be realized as hardware such as a DSP in which a program is incorporated in one semiconductor integrated circuit. If one semiconductor integrated circuit is used, an effect of reducing power consumption can be obtained.

[Summary of processing procedure of bioelectric potential measurement system]
FIG. 8 is a flowchart showing a basic processing procedure of the electroencephalograph 1 and the information processing device 2 including the bioelectric potential measurement device 1b according to the embodiment. Note that steps S11 to S14 indicate processing in the electroencephalograph 1 (step S10), and steps S21 to S25 indicate processing in the information processing apparatus 2 (step S20).

The operation input unit 11 receives an operation input performed by the user 10 (step S11). Specifically, the operation input unit 11 detects which operation button 41 is pressed at the reception timing. An example of the timing of acceptance is when the operation button 41 is pressed. The detection of whether or not the operation button 41 is pressed is performed, for example, by detecting a change in mechanical button position when the operation button 41 is pressed or a change in electric signal. Further, the operation input unit 11 detects the type of the operation input received by the operation input unit 11 according to the type of the pressed operation button 41, and outputs the operation input to the operation signal output unit 12.

Next, the operation signal output unit 12 outputs an operation signal corresponding to the operation input received by the operation input unit 11 to the information processing device 2 (step S12).

Next, the biopotential amplification unit 14 measures and amplifies the biopotential corresponding to the potential difference between the plurality of electrodes 51 in the electrode unit 13 (step S13). For example, the potential difference between the reference electrode 49 and the measurement electrode 48 disposed on the right head (the electrode position of C4 of the international 10-20 method) among the plurality of electrodes 51 in the electrode unit 13 is measured. In addition, the biopotential amplification unit 14 amplifies the measured biopotential. The amplified biopotential is output from the biopotential amplification unit 14 to the biopotential output unit 15.

Next, the bioelectric potential output unit 15 outputs the acquired bioelectric potential to the information processing device 2 (step S14).

In the processing step S10 by the electroencephalograph 1, the steps S11 and S12 and the steps S13 and S14 may be performed as parallel processes, and the processes from the step S11 to the step S14 are all in the order described above. There is no need to do it.

Subsequently, the processing step S20 in the information processing device 2 will be described.

The operation signal acquisition unit 21 acquires the operation signal output from the operation signal output unit 12 in step S12 (step S21). Further, the operation signal acquisition unit 21 outputs the acquired operation signal to the application processing unit 26.

Next, the biological potential acquisition unit 22 acquires the biological signal output from the biological potential output unit 15 in step S14 (step S22). In addition, the bioelectric potential acquisition unit 22 outputs the acquired biological signal to the bioelectric potential processing unit 23.

Next, the biological signal acquired by the biological potential acquisition unit 22 is analyzed by the biological potential processing unit 23 to extract meaningful information (step S23). For example, a biological signal of a predetermined frequency component is extracted. The predetermined frequency component is, for example, 10 Hz in the case of measurement of an electroencephalogram.

Next, the application processing unit 26 receives the operation signal from the operation signal acquisition unit 21 and the biological signal from the biological potential processing unit 23, and performs predetermined processing for executing the current application (step S24).

Next, in order to feed back the processing result of the application processing unit 26 to the user 10, the display information output unit 27 outputs the image information to the display unit 3, and the acoustic information output unit 28 outputs the acoustic information to the display unit 3. (Step S25). Thereby, the display unit 3 outputs an image and a sound corresponding to the processing result.

In processing step S20 in information processor 2, processing with Steps S22 and S23, and Step S24 may be performed as parallel processing, respectively. In addition, the application processing unit 26 does not have to perform processing using both the operation signal output from the operation signal acquisition unit 21 and the biological signal output from the biological potential processing unit 23, and only the biological signal is processed. You may use and process. In that case, step S21 for acquiring the operation signal may be omitted.

[Details of the structure of the electroencephalograph]
Subsequently, the detailed structure of the electroencephalograph 1 according to the embodiment will be described.

FIG. 9 is a perspective view showing a detailed configuration of the electroencephalograph 1 including the bioelectric potential measurement device 1b according to the embodiment. The electroencephalograph 1 shown in FIG. 9 illustrates in detail the configuration of the electroencephalograph 1 shown in FIG. 2A. Further, the electroencephalograph 1 shown in FIG. 9 is illustrated so that the outer side surface 44 and the mounting surface 45 can be seen easily for the sake of explanation, and the shape of the electroencephalograph 1 is not illustrated strictly.

The electroencephalograph 1 shown in FIG. 9 is covered by a shield member 200 in which the periphery of the plurality of electrodes 51 is disposed on the outer side surface 44.

The shield member 200 is disposed in the electroencephalograph 1 so as to cover the mounting unit 150 that the user 10 of the electroencephalograph 1 wears. The shield member 200 is an electrostatic shield for preventing extraneous noise from coming around. Moreover, in order to increase the capacitance of the electroencephalograph 1, when the electroencephalograph 1 and PC (for example, the information processing apparatus 2) are paired, etc., the current exceeding the maximum discharge current (for example, 150 mA) of the battery 81 is When it becomes necessary, the shield member 200 is configured of a plurality of capacitances 201 from the viewpoint of securing an instantaneous amount of current.

In the present embodiment, on the outer side surface 44 and the mounting surface 45 of the electroencephalograph 1, a plurality of shield members 200 configured of the electrostatic capacitance 201 are disposed. Specifically, on the outer side surface 44 of the electroencephalograph 1, a capacitance 201 having a capacitance electrode (an electrode of the capacitance 201) covering the periphery of the measurement electrode 48 as a shield member 200 is disposed. The capacitance 201 includes a dielectric and two capacitance electrodes sandwiching the dielectric. The capacitive electrode of the electrostatic capacitance 201 here means at least one of the two capacitive electrodes (positive electrode and negative electrode) sandwiching the dielectric.

A shield member 200 is disposed on the mounting surface 45 of the electroencephalograph 1 with the measurement electrode 48 interposed therebetween. Further, in the electroencephalograph 1, two wires (not shown) for connecting in parallel each of the capacitances 201 of the plurality of shield members 200 are arranged, and are continuous to the outer surface 44 and the mounting surface 45. It is arranged. For example, a capacitance value of 35 mF per capacitance is used for the

capacitance

201, and 12 capacitances connected in parallel are configured to be 400 mF or more as a whole.

Although the headphone type electroencephalograph 1 is illustrated in FIG. 9, the configuration in which the outer surface 44 is covered by the shield member 200 so as to cover the plurality of electrodes 51 in the electroencephalograph 1 described above is illustrated. The present invention may be applied to a band-type electroencephalograph 1001 shown in 2B.

Further, in FIG. 9, the shield member 200 is disposed so as to cover the mounting portion 150, but the mounting portion 150 may be configured by the shield member 200. For example, the arm 151 may be configured of the capacitance 201.

FIG. 10 is a block diagram showing a detailed configuration when the electroencephalograph 1 according to the embodiment measures a bioelectric potential. In FIG. 10, a plurality of electrodes 51 (electrodes 13 shown in FIG. 6) disposed on the mounting surface 45 of the electroencephalograph 1 of FIG. Shows an example of a dynamic connection. Further, in FIG. 10, among the plurality of electrodes 51 constituting the electrode unit 13, an electrode used as a measurement electrode is a measurement electrode 48, and an electrode used as a reference electrode is a reference electrode 49. Hereinafter, the measurement electrode 48 may be denoted as Ch1 and the reference electrode 49 may be denoted as Ref.

Further, as shown in FIG. 10, a buffer 90 a is connected to the measurement electrode 48. Similarly, the buffer 90 b is connected to the reference electrode 49. Generally, the combination of an electrode and an op amp circuit (buffer) is called an active electrode.

In FIG. 10, a configuration in which the measurement electrode 48 and the buffer 90a are combined is referred to as a first active electrode 95a, and a configuration in which the reference electrode 49 and the buffer 90b are combined is referred to as a second active electrode 95b. With an active electrode, the output of the buffer converts the impedance of the signal line to a lower value (for example 1 kΩ) even when the contact impedance of the electrode (ie the impedance of the signal source) is high (for example 30 kΩ at 10 Hz) be able to.

The potentials detected by the measurement electrode 48 and the reference electrode 49 are buffered in the

buffers

90a and 90b, respectively, as shown in FIG. The input impedance of the

buffers

90a and 90b desirably has an impedance of 500 MΩ or more at 10 Hz. Furthermore, it is desirable that the gains and input impedances of

buffers

90a and 90b be equal.

Buffers

90a and 90b may be replaced with an operational amplifier circuit whose absolute value of gain is 1 or more. In this case, amplification of the biological potential in the biological potential amplification unit 14 is the second stage amplification following the operational amplifier circuit, so the requirement for input conversion noise is alleviated compared to the case of the

buffers

90a and 90b. , Low power consumption amplifiers can be used.

The biopotential amplifier 14 of FIG. 10 amplifies the difference (voltage) (differential amplification) by taking the difference between the potential of the measurement electrode 48 and the potential of the reference electrode 49 in the bioamplifier 74 of FIG. The gain of the biological amplifier 74 is, for example, 1200 times. Also, it is desirable that the common-mode rejection ratio (CMRR) of the biological amplifier 74 be, for example, 100 dB. The amplified voltage is filtered by a low pass filter (not shown) and converted into a digital signal by an A / D converter 75 at a predetermined resolution (for example, 12 bits) and a sampling frequency (for example, 1 kHz). The data (digital data) converted into the digital signal is output to the bioelectric potential output unit 15.

The electroencephalograph 1 may have a configuration in which the

buffers

90a and 90b are not provided in the path between the measurement electrode 48 and the biopotential amplification unit 14 and between the reference electrode 49 and the biopotential amplification unit 14 . In that case, it is desirable that the input impedance of the biopotential amplification unit 14 be 500 MΩ (value at a frequency of 10 Hz) or more.

The output terminals of the first active electrode 95 a and the second active electrode 95 b are connected to the Ch 1 terminal and the Ref terminal of the biopotential amplifier 14 respectively. In the biopotential amplification unit 14, the biopotential of Ch1 is amplified (differential amplification) after taking a difference from the biopotential of Ref. The amplified biopotential is filtered by a low pass filter (not shown) and converted by the A / D converter 75 into a digital signal. Data (digital data) of the converted digital signal is output to the bioelectric potential output unit 15.

Further, in the present embodiment, the measurement electrode 48 and the buffer 90 a, and the reference electrode 49 and the buffer 90 b are covered by the shield member 200.

FIG. 11 is a block diagram for explaining a circuit configuration of a plurality of capacitances 201 provided in the electroencephalograph 1 according to the embodiment.

As shown in FIG. 11, the shield member 200 is configured of a plurality of electrostatic capacitances 201. In FIG. 11, sixteen capacitances 201 are illustrated as an example of the shield member 200.

The capacitance value of each of the plurality of capacitances 201 is set to, for example, 50 mF. Further, each of the plurality of capacitances 201 and the power supply unit 220 are grounded and have the same ground potential.

A plurality of electrostatic capacitances 201 of the shield member 200 are connected to the wiring connecting the battery 81 and the power supply unit 220. The power supply unit 220 generates a power supply voltage necessary for driving the load circuit, and supplies the power supply voltage to load circuits such as the biopotential amplification unit 14 and the biopotential output unit 15. The power supply unit 220 includes, for example, active electrodes (the first active electrode 95 a and / or the second active electrode 95 b), the biopotential amplification unit 14, and the biopotential output unit 15 (level conversion circuit not shown). Supply 1.8V power supply voltage (1.8V power supply voltage). In addition, the power supply unit 220 supplies 3.0 V (a power supply voltage of 3.0 V system) to the biopotential output unit 15 and the other load circuits in FIG. 6. Thereby, the capacitance 201 functions as a smoothing capacitor. That is, the capacitance 201 suppresses the influence of external noise on the measurement electrode 48, and smoothes the voltage of the battery 81 and various power supply voltages supplied to the load circuit by the power supply unit 220.

The capacitance control unit 210a changes the capacitance value of each of the plurality of capacitances 201 by controlling on (switch: closed) and off (switch: open) of the switches S1 to S4.

[Control of capacitance value]
Next, the details of a specific example of the procedure of changing the capacitance value of the plurality of capacitances 201 performed by the capacitance control unit 210a will be described.

FIG. 12 is a diagram for explaining an example of the relationship between the operation state of the electroencephalograph 1 according to the embodiment and the capacitance value of the capacitance 201. FIG. 13 is a timing chart for explaining an example of the relationship between the operation state of the electroencephalograph 1 according to the embodiment and the capacitance value of the capacitance 201 according to time.

The user 10 wearing the electroencephalograph 1 activates the electroencephalograph 1 at time t = t0 to turn on the power. The time t = t0 may be a time when the electroencephalograph 1 is attached. At this time, the capacitance control unit 210a controls the switches S1 to S4 to change the total value of the capacitance values of the plurality of capacitances 201 to 200 mF. For example, the capacitance control unit 210a outputs a Low (L) signal to the switches S1 to S4, and turns off the switches S1 to S4.

Next, the electroencephalograph 1 performs pairing with the information processing device 2 at time t = t1, and establishes communication with the information processing device 2. At this time, the capacitance control unit 210a controls the switches S1 to S4 to change the sum of capacitance values of the plurality of capacitances 201 to 600 mF. For example, the capacitance control unit 210a outputs a High (H) signal to the switches S1 to S3 to turn on the switches S1 to S3. Further, the capacitance control unit 210a outputs an L signal to the switch S4, and turns off the switch S4.

If the electroencephalograph 1 does not immediately acquire the bioelectric potential, it will be in a standby state after time t = t2. At this time, the capacitance control unit 210a controls the switches S1 to S4 to change the sum of capacitance values of the plurality of capacitances 201 to 300 mF. For example, the capacitance control unit 210a outputs an H signal to the switch S1, and turns on the switch S1. Further, the capacitance control unit 210a outputs an L signal to the switches S2 to S4, and turns off the switches S2 to S4.

Next, at time t = t3, the electroencephalograph 1 acquires the bioelectric potential of the user 10 in the normal mode. At this time, the capacitance control unit 210a controls the switches S1 to S4 to change the sum of capacitance values of the plurality of capacitances 201 to 400 mF. For example, the capacitance control unit 210a outputs an H signal to the switches S1 and S2, and turns on the switches S1 and S2. Further, the capacitance control unit 210a outputs an L signal to the switches S3 and S4, and turns off the switches S3 and S4.

If acquisition of the bioelectric potential of the user 10 is completed, the electroencephalograph 1 is in a standby state after time t = t11. At this time, the capacitance control unit 210a controls the switches S1 to S4 to change the sum of capacitance values of the plurality of capacitances 201 to 300 mF.

Next, the electroencephalograph 1 acquires the bioelectric potential of the user 10 in the high speed mode at time t = t12. At this time, the capacitance control unit 210a controls the switches S1 to S4 to change the sum of capacitance values of the plurality of capacitances 201 to 800 mF. For example, the capacitance control unit 210a outputs an H signal to the switches S1 to S4, and turns on the switches S1 to S4.

Furthermore, at time t = t13, the electroencephalograph 1 changes from the high speed mode to the setting for acquiring the bioelectric potential of the user 10 in the normal mode. For example, it is assumed that an instruction to change the operation mode is acquired from the user 10 through the operation button 41. At this time, the capacitance control unit 210a controls the switches S1 to S4 to change the sum of capacitance values of the plurality of capacitances 201 to 400 mF.

Next, the electroencephalograph 1 turns off (shuts off) the power at time t = t21. At this time, the capacitance control unit 210a controls the switches S1 to S4 to change the sum of capacitance values of the plurality of capacitances 201 to 200 mF. For example, the capacitance control unit 210a outputs an L signal to the switches S1 to S4, and turns off the switches S1 to S4.

Thus, the capacitance control unit 210a changes the sum of capacitance values of the plurality of capacitances 201 according to the operation mode. If the capacitance values mounted on the plurality of capacitances 201 are too large, there is a concern that the rise time of the electroencephalograph 1 may become long. Further, for example, there is a concern that the operation of the electroencephalograph 1 at the time of power on, power off, etc. becomes unstable. In particular, the power-off sequence of the electroencephalograph 1 is not normally performed when the power is shut off, which may cause the power-up of the electroencephalograph 1 to never be performed again from the next time. Therefore, the capacitance control unit 210a controls the sum of capacitance values of the plurality of capacitances 201 according to the operation mode. For example, as described above, during operation in the high speed mode, the capacitance control unit 210a sets the sum of capacitance values of the plurality of capacitances 201 to a maximum, and maximizes instantaneous current supply capability. Do.

FIG. 14 is a flowchart for describing control for changing the capacitance value of the capacitance 201 according to the operation state of the electroencephalograph 1 according to the embodiment. Specifically, FIG. 14 is a flowchart for describing an operation of controlling the sum of capacitance values of the plurality of capacitances 201 performed by the capacitance control unit 210a illustrated in FIGS. 12 and 13. .

First, the capacitance control unit 210a controls the plurality of capacitances 201 (specifically, switches S1 to S4) in advance so that the total capacitance value of the plurality of capacitances 201 is 200 mF. (Step S101). As described above, the capacitance control unit 210a sets a plurality of sums of capacitance values of the plurality of capacitances 201 to 200 mF when the power of the electroencephalograph 1 is shut down (power supply is turned off). The capacitance 201 is controlled.

The user 10 turns on the power supply of the electroencephalograph 1 (for example, to turn on the electroencephalograph 1 included in the operation button 41 shown in FIG. 2A and to turn on the power switch, the power button, etc.). 1 is started (step S102).

Next, the capacitance control unit 210a determines whether or not the power supply voltage (3.0 V power supply voltage) supplied to the load circuit by the power supply unit 220 is 2.8 V or higher (step S103). . For example, the capacitance control unit 210a determines whether or not the 3.0V power supply voltage supplied to the transmission circuit 79 by the power supply unit 220 is 2.8 V or more. In step S103, when the capacitance control unit 210a determines that the power supply unit 220 does not supply the 3.0 V power supply voltage to the load circuit at 2.8 V or more (NO in step S103), the electroencephalograph 1 The determination in step S103 is repeated, judging that it has not risen yet.

On the other hand, in step S103, when the capacitance control unit 210a determines that the 3.0 V power supply voltage of the electroencephalograph 1 is 2.8 V or more (YES in step S103), a plurality of electrostatics are generated. The plurality of capacitances 201 are controlled such that the total capacitance value of the capacitance 201 is set to 600 mF.

Next, the electroencephalograph 1 performs pairing with the information processing device 2 (step S105).

Next, the electroencephalograph 1 determines whether the pairing with the information processing device 2 is completed (step S106). In step S106, when the electroencephalograph 1 determines that the pairing with the information processing device 2 is not completed (NO in step S106), the determination of step S106 is repeated.

On the other hand, if electroencephalograph 1 determines in step S106 that the pairing with information processing device 2 is completed (YES in step S106), it determines whether to operate in the normal mode (step S107). Specifically, in step S107, the electroencephalograph 1 determines whether to operate in the normal mode in which the bioelectric potential is output to the information processing device 2 at the normal communication speed. The determination as to whether or not to operate in the normal mode may be arbitrarily determined. For example, the setting of the operation mode may be arbitrarily determined by the user 10 operating the operation button 41. Also, the setting of the operation mode may be determined by the number of electrodes 51 used to measure the biopotential. For example, the electroencephalograph 1 may operate in the high speed mode when the number of electrodes 51 used to measure the bioelectric potential is 5 or more, and may operate in the normal mode when the number is less than 5.

When the capacitance control unit 210a determines that the electroencephalograph 1 operates in the normal mode (YES in step S107), a plurality of total capacitance values of the plurality of capacitances 201 are set to 400 mF. The capacitance 201 is controlled (step S108).

Next, the electroencephalograph 1 acquires a bioelectric potential from the user 10, and outputs the acquired bioelectric potential to the information processing device 2 (step S109).

On the other hand, when the electroencephalograph 1 determines that it does not operate in the normal mode (NO in step S107), it determines whether it operates in the high speed mode (step S110).

When the capacitance control unit 210a determines that the electroencephalograph 1 operates in the high-speed mode (YES in step S110), a plurality of capacitance values of the plurality of capacitances 201 are set to 800 mF in total. The capacitance 201 is controlled (step S111).

Next, the electroencephalograph 1 acquires a bioelectric potential from the user 10, and outputs the acquired bioelectric potential to the information processing apparatus 2 (step S112).

On the other hand, when the capacitance control unit 210a determines that the electroencephalograph 1 does not operate in the high-speed mode (No in step S110), the total capacitance value of the plurality of capacitances 201 is set to 300 mF. The plurality of capacitances 201 are controlled (step S113).

Next, the electroencephalograph 1 is in a standby state (step S114).

After step S209, step S112, or step S114, the electroencephalograph 1 determines whether the power is turned off (step S115).

When it is determined that the power is not turned off (NO in step S115), the electroencephalograph 1 returns to step S107, and repeats the determination of step S107 to step S114.

On the other hand, when it is determined that the power is turned off by the electroencephalograph 1 (YES in step S115), the capacitance control unit 210a sets the sum of capacitance values of the plurality of capacitances 201 to be 200 mF. Control the plurality of capacitances 201 (step S116).

Next, the electroencephalograph 1 turns off the power (step S117).

FIG. 15 is a diagram showing input noise (input conversion noise obtained by dividing output noise by the gain of the biological amplifier 74) of the electroencephalograph 1 according to the embodiment and the electroencephalograph according to the comparative example. The solid line shown in FIG. 15 is the input noise of the electroencephalograph 1 according to the embodiment, and the broken line is the input noise of the electroencephalograph according to the comparative example. In addition, the electroencephalograph according to the comparative example is characterized in that the functional configuration is the electroencephalogram according to the embodiment except that the plurality of capacitances 201 (that is, the shield member 200) in the electroencephalograph 1 according to the embodiment is not provided. It is the same as 1 in total.

As shown in FIG. 15, in the electroencephalograph according to the comparative example, it can be confirmed that the input noise is larger than that of the electroencephalograph 1 according to the embodiment. Generally, the amplitude of the electroencephalogram input to the electroencephalograph is 20 μVpp, and in the electroencephalograph according to the comparative example, input noise exceeding 20 μVpp is partially confirmed. Therefore, the electroencephalograph according to the comparative example can not stably detect the biopotential due to the input external noise, and can not make the biopotential to be output stable signal quality.

On the other hand, in the electroencephalograph 1 according to the embodiment, input noise exceeding 20 μVpp is not confirmed. Therefore, in the electroencephalograph 1 according to the embodiment, the bioelectric potential can be stably detected, and the bioelectric potential to be output can be stabilized in signal quality.

[Application processing]
Subsequently, application processing when measuring the bioelectric potential using the bioelectric potential measurement system 100 will be described. FIG. 16 is a flowchart for explaining application processing that is changed according to the operation state of the electroencephalograph 1 according to the embodiment.

As shown in FIG. 16, the application processing unit 26 performs the processing from step S121 to step S129. Each step from step S121 to step S129 will be described in detail later. The information processed by the application processing unit 26 is, as shown in FIG. 5, an image as shown in FIG. 17, FIG. 18 and FIG. 19 as a display unit via the display information output unit 27 and the acoustic information output unit 28. Displayed on 3.

FIG. 17, FIG. 18 and FIG. 19 are diagrams showing examples of images displayed by the display unit 3 according to the operation state of the electroencephalograph 1 according to the embodiment.

The images shown in FIGS. 17, 18 and 19 are displayed on the display unit 3. The image displayed on the display unit 3 includes a measurement information display unit 3a, a biopotential waveform display unit 3b, an electrode display unit 3c, and a mode display unit 3d.

The current measurement state of the measurement electrode 48 and the reference electrode 49 is displayed on the measurement information display unit 3a. For example, when the reference electrode 49 is completely separated from the skin of the user 10 and the measurement of the biopotential is not performed, as shown in FIG. 17, “biopotential not measured”, “electrode Ref is in contact It is displayed as "No". Thereby, it can be informed that the reference electrode 49 is not in contact with the skin of the user 10, and the user 10 can be urged to wear the electroencephalograph 1 normally.

The measured bioelectric potential is displayed in time series on the bioelectric potential waveform display unit 3b. Thereby, the user 10 can visually recognize the change of the bioelectric potential.

Moreover, the contact state with the user 10 of the measurement electrode 48 (Ch1) and the reference electrode 49 (Ref) is displayed on the electrode display part 3c. For example, an image of the electroencephalograph 1 viewed from the top of the head of the user 10 is displayed on the electrode display unit 3c. The contact state of the measurement electrode 48 and the reference electrode 49 is displayed on the electrode display unit 3 c together with the positions of the measurement electrode 48 and the reference electrode 49 with respect to the body of the user 10. As a result, the user 10 can visually recognize at which position the electrode is shifted, and the electroencephalograph 1 can be worn at a normal position.

As shown in FIG. 18 and FIG. 19, in addition to the biopotential waveform currently being measured being displayed on the biopotential waveform display unit 3b, when the biopotential is being measured, the display unit 3 is used. The positions corresponding to the measurement electrode 48 and the reference electrode 49 of the displayed image may be colored and displayed. When the bioelectric potential is not measured, as shown in FIG. 17, the image showing the reference electrode 49 of the electrode display unit 3 c may be displayed in white. In the following description, a display that can be distinguished from other images may be described as “highlighted display” by displaying in color and displaying in a flickering manner instead of whiteouting. .

As shown in FIG. 19, when the measurement electrodes 48 are attached to a plurality of positions of the user 10, for example, the positions of the respective measurement electrodes 48 correspond to the positions of the electrode display portions according to the positions of the attached measurement electrodes 48. It is displayed on the electrode position display sections 3c1 to 3c5 of 3c. In addition, channels (Ch1 to Ch5) corresponding to the respective electrode positions are displayed on the electrode display unit 3c.

The mode display unit 3d shown in FIGS. 18 and 19 displays the operation mode that the electroencephalograph 1 is executing. For example, when the electroencephalograph 1 is operating in the normal mode, the mode display unit 3 d displays “normal mode”. Further, for example, when the electroencephalograph 1 is operating in the high speed mode, the mode display unit 3 d displays “high speed mode”.

Subsequently, each step of application processing performed by the application processing unit 26 will be described with reference to an image displayed on the display unit 3 shown in FIGS. 17 to 19.

First, the application processing unit 26 determines whether or not the bioelectric potential is being measured based on the output result of the bioelectric potential processing unit 23 (step S121). For the application processing unit 26 to perform the determination, for example, the electroencephalograph 1 may include a contact impedance measuring device (not shown) for measuring the contact impedance between each electrode and the user 10. In this case, the application processing unit 26 determines that the electrode unit 13 is a living body based on the determination result of whether or not the measurement electrode 48 and the reference electrode 49 are in contact with the skin of the user 10 output from the contact impedance measuring device. It is determined whether or not the potential is being measured.

When the application processing unit 26 determines that the measurement electrode 48 and the reference electrode 49 measure the bioelectric potential (YES in step S121), for example, as shown in FIG. 18, through the display information output unit 27, A message "during biopotential measurement" is displayed on the display unit 3 (step S122). On the measurement information display unit 3a of the display unit 3, "Bioelectric potential measurement in progress" is displayed.

On the other hand, when the application processing unit 26 determines that the measurement electrode 48 and the reference electrode 49 do not measure the biopotential (NO in step S121), for example, “biopotential not measured” via the display information output unit 27 "" Is displayed on the display unit 3 (step S123). On the measurement information display unit 3 a of the display unit 3, as shown in FIG. 17, “biopotential not measured” is displayed. For example, when the reference electrode 49 (Ref) is not in contact with the skin of the user 10, as shown in FIG. 17, “the electrode Ref is not in contact” is displayed on the measurement information display unit 3a and processed Ends.

After step S122, the display information output unit 27 detects an electrode used for measurement (step S124).

Next, the display information output unit 27 causes the display unit 3 to highlight the image representing the electrode used for measuring the bioelectric potential (step S125). For example, in the case where the display information output unit 27 detects the measurement electrode 48 (Ch1) and the reference electrode 49 (Ref) as the electrodes used for measurement, the display information output unit 27 sets the measurement electrode 48 (Ch1) and the reference electrode 49 (Ref) as electrodes. The highlight is displayed on the display unit 3c. For example, as shown in FIG. 18, the display unit 3 displays the measurement electrode 48 and the reference electrode 49 on the electrode display unit 3c with a picture of the electrodes.

Next, the display information output unit 27 calculates the number of electrodes used for measuring the bioelectric potential. As an example, the display information output unit 27 determines whether the number of electrodes used for measurement is five or more (step S126). In the flowchart shown in FIG. 16, the operation mode is determined by the number of electrodes used to measure the bioelectric potential.

When the display information output unit 27 determines that the number of electrodes used for measuring the bioelectric potential is five or more (YES in step S126), as shown in FIG. The mode is displayed (step S127).

On the other hand, when the display information output unit 27 determines that the number of electrodes used for measuring the bioelectric potential is less than 5 (NO in step S126), the mode display unit 3d is displayed as shown in FIG. The "normal mode" is displayed (step S128).

After step S127 or step S128, the display information output unit 27 causes the biopotential waveform display unit 3b to display the signal waveform of the biopotential measured by each electrode (step S129). For example, in the case of one electrode, one signal waveform is displayed on the biopotential waveform display unit 3b as shown in FIG. 18, and in the case of multiple electrodes, a plurality of signal waveforms are biopotential as shown in FIG. It is displayed on the waveform display unit 3b. In FIG. 19, although five biological signal waveforms corresponding to the number of measurement electrodes 48 are displayed on the biological potential waveform display unit 3b, they are shown in a simplified manner.

[Effects, etc.]
As described above, the biopotential measurement device 1b according to the present embodiment is a biopotential measurement device for measuring the biopotential. The biopotential measuring device 1 b includes a measuring electrode 48 in contact with a living body, a biopotential amplification unit 14 that amplifies the biopotential detected by the measuring electrode 48, and a living body that outputs the biopotential amplified by the biopotential amplification unit 14. And a potential output unit 15. The biopotential measuring device 1 b further includes a power supply unit 220 that supplies power to at least one of the biopotential amplification unit 14 and the biopotential output unit 15, and a capacitance connected to a wire that covers the periphery of the measurement electrode 48 as the shield member 200. And a capacitance 201 having an electrode. Further, the ground potential of the power supply unit 220 is electrically connected to the ground potential of the electrostatic capacitance 201.

According to such a configuration, the electrostatic capacitance 201 serves as an electrostatic shield, and it is possible to suppress external noise that affects the measurement electrode 48. Thereby, the biopotential detected by the measurement electrode 48 is likely to be stabilized. Therefore, according to the biopotential measurement device 1b, stable biopotential measurement of signal quality can be performed.

Further, by adopting the capacitance 201 as a shield, it is possible to secure the discharge current other than the battery 81. Thereby, the stability of the operation of the bioelectricity measuring device 1b is improved. Therefore, according to the biopotential measurement device 1b, stable biopotential measurement of signal quality can be performed.

In addition, the bioelectric potential measurement apparatus 1 b further changes the sum of the capacitance values of the plurality of capacitances 201 according to the plurality of capacitances 201 and the operation mode of the bioelectric potential output unit 15. And 210a.

If the capacitance value of the capacitance 201 mounted on the biopotential measurement device 1b is too large, the rise time becomes long, and there is also a concern that the operation at the time of start-up such as when the power is shut off becomes unstable. By appropriately adjusting the total capacitance value of the capacitance 201 mounted on the biopotential measurement device 1b, the rise time is unlikely to be long, and the operation at the time of rise, power interruption, etc. is easily stabilized.

For example, the capacitance control unit 210a may change the sum of capacitance values of the plurality of capacitances 201 between when the power of the power supply unit 220 is turned on and when the power of the power supply unit 220 is turned off.

Also, for example, when the bioelectric potential output unit 15 outputs the bioelectric potential, the electrostatic capacity control unit 210a may change the sum of the capacitance values of the plurality of electrostatic capacitances 201.

As described above, by appropriately adjusting the total of the capacitance values of the capacitances 201 mounted on the biopotential measurement device 1b, the rise time does not easily become long, and the operation at the time of rising of the battery 81, power interruption, etc. is stable. It becomes easy to do.

In addition, the capacitance control unit 210a according to the present embodiment detects the bioelectric potential by the measurement electrode 48, and switches the mode between the normal mode in which the bioelectric potential output unit 15 outputs the detected bioelectric potential to the high speed mode. It may control. In the high-speed mode, the capacitance control unit 210a detects the bioelectric potential at the measurement electrode 48, and outputs the detected bioelectric potential per unit time by a larger amount of data of the bioelectric potential than in the normal mode. Make the part 15 output. Further, in the mode control, the capacitance control unit 210a may perform control to increase the sum of the capacitance values of the plurality of capacitances 201 in the high-speed mode than in the normal mode.

For example, when operating in the high speed mode, the capacitance control unit 210a sets the sum of capacitance values of a plurality of capacitances to a maximum, and maximizes the current supply capability. Thus, by appropriately adjusting the total of the capacitance values of the capacitance 201, the biological potential measurement device 1b can perform communication operation quickly and easily.

The capacitance 201 according to the present embodiment may be an electric double layer capacitance.

Thereby, weight reduction of the bioelectric potential measuring device 1b is attained.

The capacitance control device 210 according to the present embodiment is a capacitance control device that controls a plurality of capacitances 201 included in a biopotential measurement device 1 b for measuring a biopotential. The biopotential measuring device 1b outputs the biopotential amplified by the biopotential amplifier 14 and the biopotential amplifier 14 that amplifies the biopotential detected by the measuring electrode 48, which is in contact with the living body, and the bioelectrode. And a bioelectric potential output unit 15. In addition, the bioelectric potential measurement apparatus 1b includes a plurality of capacitances 201 having capacitance electrodes to which the wiring covering the periphery of the measurement electrode 48 is connected as the shield member 200, and a power supply unit 220 receiving power supply from the capacitances 201. And The capacitance control device 210 changes the sum of capacitance values of the plurality of capacitances 201 in the biological potential measurement device 1b in which the ground potential of the power supply unit 220 is electrically connected to the ground potential of the capacitance 201. A capacitance control unit 210a is provided.

As a result, by appropriately adjusting the total capacitance value of the capacitance 201 mounted on the biopotential measurement device 1b, the rise time is unlikely to be long, and the operation at the time of rise, at the time of power shut off, etc. is stable. It becomes easy to do.

The electroencephalograph 1 according to the present embodiment includes a bioelectric potential measurement device 1b and a mounting unit 150 mounted on the head of a living body whose bioelectric potential is to be measured. The measurement electrode 48 is disposed on the mounting unit 150 so as to be in contact with the head of the living body when measuring the biopotential of the living body.

As shown in FIG. 15, according to the electroencephalograph 1 according to the embodiment, it is possible to suppress the input extraneous noise to be equal to or less than the amplitude of a general electroencephalogram. That is, the bioelectric potential measurement device 1b according to the embodiment is suitable for the electroencephalograph 1 for measuring an electroencephalogram.

For example, the capacitance 201 provided in the electroencephalograph 1 according to the present embodiment may be arranged to cover the mounting unit 150.

Also, for example, the mounting unit 150 of the electroencephalograph 1 according to the present embodiment may be configured of the electrostatic capacitance 201.

Thereby, the electrostatic capacitance 201 functions as a shield which prevents the external noise to each circuit and the electrode 51 with which the electroencephalograph 1 is provided. Therefore, according to the electroencephalograph 1, bioelectric potential measurement of stable signal quality can be performed.

Further, the capacitance control method according to the present embodiment is a capacitance control method of the plurality of capacitances 201 included in the biopotential measuring device 1 b that measures biopotential. The biopotential measuring device 1b outputs the biopotential amplified by the biopotential amplifier 14 and the biopotential amplifier 14 that amplifies the biopotential detected by the measuring electrode 48, which is in contact with the living body, and the bioelectrode. And a bioelectric potential output unit 15. In addition, the bioelectric potential measurement apparatus 1b includes a capacitance 201 having a capacitance electrode to which a wire covering the periphery of the measurement electrode 48 is connected as a shield member 200, and a power supply unit 220 receiving power supply from the capacitance 201. Prepare. The ground potential of the power supply unit 220 is electrically connected to the ground potential of the capacitance. The capacitance control method includes a determination step of determining whether the power supply unit 220 is in the on state or the off state, and a sum of capacitance values of the plurality of capacitances 201 according to the state determined in the determination step. Control steps to change

The present invention may also be implemented as a program that causes a computer to execute the steps included in the capacitance control method according to the present embodiment. The program may also be realized as a non-volatile recording medium such as a compact disc-read only memory (CD-ROM) readable by a computer. Also, the present invention may be realized as information, data or signals indicating the program. And these programs, information, data, and signals may be distributed via a communication network such as the Internet.

As a result, the capacitance control method can be executed by the computer as a program capable of simply and stably measuring bioelectric potential of signal quality.

(Other embodiments)
The biopotential measurement device, the capacitance control device, the electroencephalograph, the capacitance control method, and the program according to the embodiment of the present disclosure have been described above, but the present disclosure is limited to the above-described embodiment is not.

For example, although the biopotential measurement device, the capacitance control device, and the capacitance control method have been described as one aspect of the present disclosure in the above embodiment, the present disclosure allows a computer to execute the method described above. It may be a program. Further, the present disclosure may be a digital signal including a program of the computer.

Furthermore, the present disclosure relates to a non-transitory recording medium that can read the computer program or the digital signal from a computer, such as a flexible disk, a hard disk, a CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, a BD It may be recorded on a Blu-ray (registered trademark) Disc), a semiconductor memory, or the like. Further, the present invention may be the digital signal recorded on these non-temporary recording media.

Further, the present disclosure may transmit the computer program or the digital signal via a telecommunications line, a wireless or wired communication line, a communication network represented by the Internet, data broadcasting, and the like.

Also, the standard of wireless communication in the present disclosure is Bluetooth (registered trademark), BLE (Bluetooth (registered trademark) Low Energy), ANT (registered trademark), Wi-Fi (registered trademark), Zigbee (registered trademark), or the like. It may be a proprietary communication standard.

Further, the present disclosure may be a computer system including a microprocessor and a memory, the memory storing the computer program, and the microprocessor operating according to the computer program.

In addition, by recording and transferring the program or the digital signal on the non-temporary recording medium, or by transferring the program or the digital signal via the communication network etc. May be implemented by a computer system of

Furthermore, for example, in the above-described embodiment, an electroencephalogram is assumed as the bioelectric potential to be measured, but the bioelectric potential to be measured is not limited to the electroencephalogram, and may be an electrocardiogram, an myoelectric potential, or an electrooculogram Or other biometric information. In this case, as described above, the shape of the device for measuring the bioelectric potential is not limited to the headphone type and the band type, and may be another shape in accordance with the mounting position.

Also, the electrode may be an active electrode provided with an amplifier, or may be a digital active electrode capable of converting a biomedical signal into a digital value.

Also, at least one measurement electrode and one reference electrode may be provided, or a plurality of measurement electrodes and reference electrodes may be provided.

The electroencephalograph and the information processing apparatus may be communicably connected by wire or may be communicably connected by wireless. Further, the information processing apparatus and the display unit may be communicably connected by wire or may be communicably connected by wireless.

Also, the steps in the above-described embodiment may be changed or omitted. Also, the order of the steps may be reversed. Also, processing of a plurality of steps may be performed in parallel.

In addition, the embodiments can be realized by various combinations of the embodiments that can be conceived by those skilled in the art, or by combining components and functions in the embodiments within the scope of the present disclosure. This form is also included in the present disclosure.

1, 1001 electroencephalograph 1a operation input device 1b bioelectric potential measurement device 2 information processing device 3 display unit 3a measurement information display unit 3b biopotential waveform display unit 3c electrode display unit 3c1, 3c2, 3c3, 3c4, 3c5 electrode position display unit 3d Mode display unit 10 user 11 operation input unit 12 operation signal output unit 13 electrode unit 14 biopotential amplification unit 15 biopotential output unit 21 operation signal acquisition unit 22 biopotential acquisition unit 23 biopotential processing unit 26 application processing unit (application processing unit )
27 Display information output unit 28 Acoustic information output unit 41 Operation button 43 Operation surface 44 Outer surface 45 Mounting surface 46 Ear rest 47 Display 48 Measurement electrode 49 Reference electrode 51 Electrode (electrode for measuring biopotential)
68, 80 Antenna 71 Operation Button Group 72 Control Signal Conversion Circuit 73c Earthing Electrode 74 Biological Amplifier 75 A /

D Converter

78, 108 Signal Processing Unit 79 Transmission Circuit 81 Battery 82 Reception Circuit 84 Image Control Circuit 85 Display Information Output Circuit 86 Sound Control Circuit 87 acoustic information output circuit 88

power supply

90a, 90b buffer 95a first active electrode 95b second active electrode 100

biopotential measurement system

101, 111, 211 CPU
102, 112, 212 RAM
103, 113, 213

programs

104, 114, 214 ROM
DESCRIPTION OF

SYMBOLS

105, 115 Bus 150 Mounting part 151 Arm 200 Shield member 201 Capacitance 210 Capacitance control device 210a Capacitance control part 220 Power supply part S1, S2, S3, S4 switch

Claims

A biopotential measuring device for measuring a biopotential comprising:
Measuring electrodes in contact with the living body,
A biopotential amplification unit for amplifying a biopotential detected by the measurement electrode;
A biopotential output unit that outputs the biopotential amplified by the biopotential amplification unit;
A power supply unit for supplying power to at least one of the biopotential amplification unit and the biopotential output unit;
And a capacitance having a capacitive electrode connected to a wire covering the periphery of the measurement electrode as a shield member,
The ground potential of the power supply unit is electrically connected to the ground potential of the electrostatic capacitance.
Furthermore, a plurality of said capacitances,
The bioelectric potential measurement device according to claim 1, further comprising: a capacitance control unit that changes a sum of capacitance values of the plurality of capacitances according to an operation mode of the bioelectric potential output unit.
The capacitance control unit
The bioelectric potential measurement device according to claim 2, wherein a sum of capacitance values of the plurality of electrostatic capacitances is changed between when the power supply unit is turned on and when the power supply unit is turned off.
The bioelectric potential measurement device according to claim 2 or 3, wherein the capacitance control unit changes a sum of capacitance values of the plurality of capacitors when the bioelectric potential output unit outputs the bioelectric potential.
The capacitance control unit
The bioelectric potential is detected by the measurement electrode, and the bioelectric potential is detected by the measurement electrode, and the bioelectric potential detected is output per unit time in the normal mode in which the bioelectric potential detected is output to the bioelectric potential output unit Mode control for switching to a high speed mode in which the amount of data of the biopotential concerned is output to the biopotential output unit more than the normal mode,
The bioelectric potential measurement device according to any one of claims 2 to 4, wherein in the mode control, the high speed mode controls the sum of capacitance values of the plurality of capacitances to be higher than the normal mode. .
The bioelectric potential measurement device according to any one of claims 1 to 5, wherein the capacitance is an electric double layer capacitance.
A capacitance control device for controlling a plurality of capacitances included in a biopotential measuring device for measuring a biopotential, comprising:
The biopotential measuring device
Measuring electrodes brought into contact with the living body,
A biopotential amplification unit for amplifying a biopotential detected by the measurement electrode;
A biopotential output unit that outputs the biopotential amplified by the biopotential amplification unit;
A plurality of capacitances each having a capacitance electrode connected to a wire covering a periphery of the measurement electrode as a shield member;
A power supply unit that receives supply of power from the capacitance;
The capacitance control device changes the sum of capacitance values of the plurality of capacitances in the biopotential measuring device in which the ground potential of the power supply unit is electrically connected to the ground potential of the capacitance. A capacitance control device comprising a capacitance control unit.
The bioelectric potential measurement device according to any one of claims 1 to 6,
And a mounting unit mounted on a head of the living body whose biopotential is to be measured.
The measurement electrode is disposed on the mounting unit so as to be in contact with the head of the living body when the bioelectric potential of the living body is measured.
The electroencephalograph according to claim 8, wherein the capacitance is arranged to cover the mounting portion.
The electroencephalograph according to claim 8, wherein the mounting unit is configured by the capacitance.
A capacitance control method for a plurality of capacitances included in a biopotential measuring device for measuring a biopotential, comprising:
The biopotential measuring device
Measuring electrodes brought into contact with the living body,
A biopotential amplification unit for amplifying a biopotential detected by the measurement electrode;
A biopotential output unit that outputs the biopotential amplified by the biopotential amplification unit;
A capacitance having a capacitive electrode connected to a wire covering a periphery of the measurement electrode as a shield member;
A power supply unit that receives supply of power from the capacitance;
The ground potential of the power supply unit is electrically connected to the ground potential of the capacitance,
The capacitance control method is
A determination step of determining whether the power supply unit is in the on state or the off state;
A control step of changing a sum of capacitance values of the plurality of capacitances in accordance with the state determined in the determination step.
A program for causing a computer to execute a capacitance control method of a plurality of capacitances included in a biopotential measuring device for measuring a biopotential, comprising:
The biopotential measuring device
Measuring electrodes brought into contact with the living body,
A biopotential amplification unit for amplifying a biopotential detected by the measurement electrode;
A biopotential output unit that outputs the biopotential amplified by the biopotential amplification unit;
A capacitance having a capacitive electrode connected to a wire covering a periphery of the measurement electrode as a shield member;
A power supply unit that receives supply of power from the capacitance;
The ground potential of the power supply unit is electrically connected to the ground potential of the capacitance,
The capacitance control method is
A determination step of determining whether the power supply unit is in the on state or the off state;
A control step of changing the sum of capacitance values of the plurality of capacitances according to the state determined in the determination step, and a program for causing a computer to execute the capacitance control method.