Electrical signal measuring device, electrical signal measuring system, and electrical signal measuring method

Abstract

Provided is an electrical signal measurement device comprising at least: an electrode for detecting an electrical signal from a living body in order to measure biological information with high precision even when the state of contact between the electrode and the living body changes due to body movement, etc.; a determination unit for determining a voltage to use in common-mode feedback on the basis of information on the state of contact between the living body and the electrode, obtained from the electrical signal; and a feedback unit for applying the voltage to the living body.

Description

[Technical field]

[0001] The present technology relates to an electric signal measuring device, an electric signal measuring system, and an electric signal measuring method. [Background technology]

[0002] Conventionally, in daily life, a technique for measuring biological information such as an electroencephalogram signal, an electrocardiogram signal, or a skin potential signal is used. It is known that common mode noise occurs in the measurement of biological information due to the presence of an external electromagnetic field. This common mode noise causes a problem that biological information cannot be measured with high accuracy.

[0003] In order to reduce this common mode noise, for example, Non-Patent Document 1 and Patent Document 1 describe a technology for reducing common mode noise by inverting and amplifying the components equivalent to the common mode noise and feeding them back to the living body via electrodes. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Bruce B. Winter, John G. Webster, “Driven-Right-Leg Circuit Design”, IEEE, IEEE Transactions on Biomedical Engineering (1983): 62-66 [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2012-532731 Summary of the Invention [Problem to be solved by the invention]

[0006] Wet electrodes, which are commonly used in research and medical applications, are electrodes that use gel, saline, or the like to reduce contact impedance with a living body.

[0007] However, in daily life, it is difficult to use wet electrodes due to reasons such as dirt on the user's skin surface, changes over time, and the time required. In daily life, dry electrodes are expected to be used.

[0008] Dry electrodes are easy to attach, but there is a problem in that if the contact state between the electrode and the living body changes due to, for example, body movement or improper attachment, the reduction of common mode noise becomes insufficient.

[0009] Therefore, the main objective of the present technology is to provide an electrical signal measuring device, an electrical signal measuring system, and an electrical signal measuring method that measure biological information with high accuracy even if the contact condition between the electrode and the living body changes due to, for example, body movement. [Means for solving the problem]

[0010] In order to solve the above problem, the present technology provides an electrical signal measuring device comprising at least an electrode that detects an electrical signal from a living organism, a determination unit that determines a voltage to be used for common-mode feedback based on contact state information between the living organism and the electrode obtained from the electrical signal, and a feedback unit that applies the voltage to the living organism. The electrode may be a dry electrode. The contact state information may include a contact impedance. The contact state information may include an amplitude of the electrical signal. The determination unit may compare the contact state information with a predetermined threshold value to determine the voltage. The determination unit may determine the voltage by analyzing a trend of the contact state information. The electrode may include a switch. The electrodes may have a variable resistance. The present technology also provides an electrical signal measurement system comprising at least an electrode that detects an electrical signal from a living organism, a determination unit that determines a voltage to be used for common-mode feedback based on contact state information between the living organism and the electrode obtained from the electrical signal, and a feedback unit that applies the voltage to the living organism. The present technology also provides an electrical signal measuring method that includes at least the steps of: an electrode detecting an electrical signal from a living organism; determining a voltage to be used for common-mode feedback based on contact state information between the living organism and the electrode obtained from the electrical signal; and the electrode applying the voltage to the living organism. [Brief description of the drawings]

[0011] [Figure 1] 1 is a circuit diagram showing a circuit configuration of an electrical signal measuring device according to an embodiment of the present technology. [Diagram 2] 11 is a flowchart illustrating a procedure of a determination unit according to an embodiment of the present technology. [Diagram 3] FIG. 1 is a circuit diagram showing a circuit configuration of a comparative example of an electrical signal measuring device. [Figure 4] FIG. 1 is a circuit diagram of an electrical signal measuring device used in verification. [Diagram 5] FIG. 11 is an explanatory diagram of a verification result. [Figure 6] FIG. 11 is an explanatory diagram of a verification result. [Figure 7] 1 is a circuit diagram showing a circuit configuration of an electrical signal measuring device according to an embodiment of the present technology. [Figure 8] 1 is a circuit diagram showing a circuit configuration of an electrical signal measuring device according to an embodiment of the present technology. [Figure 9] 1 is a circuit diagram showing a circuit configuration of an electrical signal measuring device according to an embodiment of the present technology. [Figure 10] 1 is a circuit diagram showing a circuit configuration of an electrical signal measuring device according to an embodiment of the present technology. [Figure 11] 1 is a circuit diagram showing a circuit configuration of an electrical signal measuring device according to an embodiment of the present technology. [Figure 12]1 is a block diagram showing a configuration of an electrical signal measuring system according to an embodiment of the present technology. [Figure 13] 1 is a flowchart showing a procedure of an electrical signal measuring method according to an embodiment of the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A preferred embodiment for implementing the present technology will be described below. The embodiment described below shows an example of a typical embodiment of the present technology, and the scope of the present technology will not be narrowly interpreted by this. Unless otherwise specified, in the drawings, "upper" means the upper direction or upper side in the drawing, "lower" means the lower direction or lower side in the drawing, "left" means the left direction or left side in the drawing, and "right" means the right direction or right side in the drawing. In addition, in the drawings, the same or equivalent elements or members are given the same reference numerals, and duplicated explanations are omitted.

[0013] The present technology will be described in the following order. 1. First embodiment of the present technology (example 1 of electrical signal measuring device) (1) Overview of the Present Invention (2) Judgment section (3) Verification 2. Second embodiment of the present technology (example 2 of electrical signal measuring device) 3. Third embodiment of the present technology (third example of electrical signal measuring device) 4. Fourth embodiment of the present technology (example 4 of electrical signal measuring device) 5. Fifth embodiment of the present technology (example 5 of electrical signal measuring device) 6. Sixth embodiment of the present technology (sixth example of electrical signal measuring device) 7. Seventh embodiment of the present technology (electrical signal measurement system) 8. Eighth embodiment of the present technology (electrical signal measuring method)

[0014] [1. First embodiment of the present technology (example 1 of electrical signal measuring device)] [(1) Overview of this embodiment] An electrical signal measuring device according to a first embodiment of the present technology will be described with reference to Fig. 1. Fig. 1 is a circuit diagram showing a circuit configuration of the electrical signal measuring device according to the first embodiment.

[0015] As shown in FIG. 1, the electrical signal measuring device 1000 according to this embodiment at least includes a plurality of electrodes 100 to 300, a determination section 500, and a feedback section 400.

[0016] Each of the electrodes 100 to 300 is disposed at a position in contact with the skin surface of the living body S or at a position close to the skin surface of the living body S. Each of the electrodes 100 to 300 detects an electric signal from the living body S. Examples of the electric signal include an electroencephalogram (EEG) signal, an electrocardiogram (ECG) signal, a magnetocardiogram (MCG) signal, a magnetoencephalogram (MEG) signal, a surface electromyogram (EMG) signal, an electrooculogram (EOG) signal, and an electrodermal activity (EDA) signal.

[0017] The multiple electrodes 100 to 300 will be described in more detail. The multiple electrodes 100 to 300 may be composed of a first detection electrode 100, a second detection electrode 200, and a third detection electrode 300. The number of the multiple electrodes 100 to 300 is not limited to three.

[0018] In this embodiment, each of the first detection electrode 100 and the second detection electrode 200 detects an electrical signal from the living organism S. The third detection electrode 300 detects an electrical signal from the living organism S that serves as a reference for the electric potential.

[0019] Each of the multiple electrodes 100 to 300 may be a dry electrode. Since each of the multiple electrodes 100 to 300 is a dry electrode, the electrical signal measuring device 1000 can measure the electrical signal from the living body S with high accuracy even if the contact state between the electrode and the living body S changes due to, for example, body movement.

[0020] The feedback section 400 applies a voltage to the living body S. To explain in more detail, the feedback section 400 reduces the common mode noise by inverting and amplifying a component corresponding to the common mode noise and feeding it back to the living body (common feedback).

[0021] The first sensing electrode 100 is composed of a first passive electrode 110 and a first active electrode 120. The first active electrode 120 can include, for example, a first switch 121, a first instrumentation amplifier 122, a first resistor 123, a first AD converter 124, and a first switch switching unit 125.

[0022] The second sensing electrode 200, like the first sensing electrode 100, is composed of a second passive electrode 210 and a second active electrode 220. The second active electrode 220 can include, for example, a second switch 221, a second instrumentation amplifier 222, a second resistor 223, a second AD converter 224, and a second switch switching unit 225.

[0023] The third sensing electrode 300 is composed of a third passive electrode 310 and a first operational amplifier 321 .

[0024] The feedback section 400 is composed of a fourth passive electrode 410 and a second operational amplifier 421 .

[0025] The determination unit 500 is electrically connected to each of the electrodes 100-300 and the feedback unit 400. The determination unit 500 obtains contact state information between the living body S and each of the electrodes 100-300 from the electrical signals detected by each of the electrodes 100-300. Then, the determination unit 500 determines the voltage to be used for the common mode feedback based on the contact state information. The determination unit 500 can be realized by using, for example, a microcomputer or the like.

[0026] The feedback section 400 applies the voltage determined by the determination section 500 to the living body S.

[0027] [(2) Judgment section] The flow of processing performed by the determination unit 500 will be described with reference to Fig. 2. Fig. 2 is a flowchart showing the procedure of the determination unit according to this embodiment.

[0028] 2, the determination unit 500 obtains contact state information between the living body S and each of the electrodes 100 to 300 from an electrical signal detected by each of the electrodes 100 to 300 (S1). This contact state information may include, for example, a contact impedance or an amplitude of the electrical signal.

[0029] Next, the determination unit 500 determines the voltage to be used for common feedback based on the obtained contact state information (S2). This determination method is not particularly limited, but to explain one example, the determination unit 500 may compare the contact state information with a predetermined threshold value to determine the voltage. For example, when the contact impedance, which is an example of contact state information, is equal to or greater than the predetermined threshold value (S2: Yes), the determination unit 500 separates the detection electrode that detects the electric signal including this contact state information from the circuit (S3). Note that this predetermined threshold value is not particularly limited.

[0030] This separation will be described with reference to Fig. 1. In the electrical signal measuring device 1000 according to this embodiment, for example, it is assumed that the first detection electrode 100 detects an electrical signal including contact state information equal to or greater than a predetermined threshold. In other words, it is assumed that the contact state between the first passive electrode 110 included in the first detection electrode 100 and the living body S is poor.

[0031] The determination unit 500 separates the first detection electrode 100 from the circuit. At this time, the determination unit 500 instructs the first switch changeover unit 125 to separate. The first switch changeover unit 125 changes the first switch 121 from the on state to the off state. As a result, the first detection electrode 100 is separated from the circuit.

[0032] The first switch 121 is realized by using, for example, a MOSFET. At this time, the first switch control unit 125 applies a predetermined voltage to the first switch 121 to change the first switch 121 from an on state to an off state.

[0033] Although details will be described later, the detection electrodes do not necessarily have to be separated by a physical switch, and may be separated by digital signal processing, for example.

[0034] Returning to the description of Fig. 2, the determination unit 500 analyzes the tendency of the contact state information contained in the electrical signals detected by all the detection electrodes, and determines the voltage to be used for the common mode feedback. That is, when the determination is completed for all the detection electrodes (S4: Yes), the determination unit 500 determines the voltage to be used for the common mode feedback (S5).

[0035] Next, the feedback section 400 applies the voltage determined by the determination section 500 to the living body S. This allows appropriate common mode feedback, allowing the electric signal measuring device 1000 to measure the electric signal with high accuracy.

[0036] The timing at which each of the multiple switches 121 and 221 is turned on and off may be each time an electrical signal is detected, or may be a predetermined number of times.

[0037] Furthermore, an external reference signal obtained from, for example, an acceleration sensor or the like may be used as a trigger for the determination by the determination unit 500. Alternatively, the determination unit 500 configured with, for example, an event-driven algorithm may start processing when, for example, the contact state information changes to or exceeds a predetermined threshold value.

[0038] The determination unit 500 may make a determination using the amplitude of the electrical signal in addition to the contact impedance described above. For example, when the amplitude is equal to or greater than a predetermined threshold, the determination unit 500 may disconnect the detection electrode that detects the electrical signal including this amplitude from the circuit. By using the amplitude of the electrical signal, a similar effect can be obtained with a simpler circuit without using a current source.

[0039] The determination unit 500 may determine the voltage used for the common mode feedback using a statistical algorithm. The determination unit 500 may determine the voltage used for the common mode feedback based on, for example, the degree of variation from the average value in all the detection electrodes.

[0040] Here, the effect of the present technology will be described with reference to Fig. 3. Fig. 3 is a circuit diagram showing a circuit configuration of a comparative example of an electrical signal measuring device for explaining the effect of the present technology.

[0041] 3, an electrical signal measuring device 2000 according to a comparative example includes at least a plurality of electrodes 100-300, a control unit 700, and a feedback unit 400. It is assumed that, among the plurality of electrodes 100-300, for example, the first passive electrode 110 of the first detection electrode 100 is in poor contact with the living body S. In this case, the electrical signal detected by the first detection electrode 100 contains a lot of noise.

[0042] The control unit 700 performs common feedback by applying a voltage to the living body S via the feedback unit 400 based on the electrical signals obtained by each of the multiple electrodes 100 to 300. However, there is a problem that the electrical signal from the living body S cannot be measured with high accuracy because this noise is superimposed and applied.

[0043] By removing this noise, the electric signal measuring device 1000 according to an embodiment of the present technology has an effect of being able to measure with high accuracy the electric signal from the living organism S. The same effect is also achieved in other embodiments described below.

[0044] In the present embodiment, an electrical signal from a living body is measured, but the measurement target is not limited to a living body. For example, a solid, liquid, or gas having any circuit characteristics may be measured.

[0045] [(3) Verification] The results of verifying the effect of removing this noise will be described with reference to Figures 4 to 6. Figure 4 is a circuit diagram of the electrical signal measuring device used in this verification. Note that this circuit diagram is merely an example, and the circuit configuration of the electrical signal measuring device 1000 is not limited to that shown in Figure 4.

[0046] As shown in Fig. 4, this circuit includes a first channel Ch1 and a second channel Ch2. Each of the first channel Ch1 and the second channel Ch2 has input terminals (Sig_IN, REF_IN) corresponding to electrodes. Note that the contact impedance of the second channel Ch2 is higher than the contact impedance of the first channel Ch1.

[0047] Fig. 5 is an explanatory diagram of the verification results. In Fig. 5, the first graph G1 shows the frequency and amplitude of the electrical signal input to each of the multiple input terminals (Sig_IN, REF_IN) when common mode feedback (DRL: Driven Right Leg) is not performed. As shown in the first graph G1, this electrical signal contains common mode noise.

[0048] The second graph G2 shows the frequency and amplitude of the electrical signals input to each of the multiple input terminals (Sig_IN, REF_IN) when common mode feedback is performed based on the electrical signal obtained from the first channel Ch1. The electrical signal obtained from the first channel Ch1, which has a low contact impedance, is used for common mode feedback. The electrical signal obtained from the second channel Ch2, which has a high contact impedance, is not used for common feedback.

[0049] As shown in the second graph G2, the common mode noise shown in the first graph G1 is eliminated. In addition, since the electrical signal obtained from the second channel Ch2, which has a high contact impedance, is not used, the electrical signal is measured with high accuracy.

[0050] The third graph G3 shows the frequency and amplitude of the electrical signals input to each of the multiple input terminals (Sig_IN, REF_IN) when common mode feedback is performed based on the electrical signal obtained from the second channel Ch2. The electrical signal obtained from the first channel Ch1, which has a low contact impedance, is not used for common mode feedback. The electrical signal obtained from the second channel Ch2, which has a high contact impedance, is not used for common mode feedback.

[0051] As shown in the third graph G3, the amplitude is unstable because the electrical signal obtained from the second channel Ch2, which has a high contact impedance, is used, and the electrical signal cannot be measured with high accuracy. In addition, common mode noise is not eliminated.

[0052] The fourth graph G4 shows the frequency and amplitude of the electrical signals input to each of the multiple input terminals (Sig_IN, REF_IN) when common mode feedback is performed based on the electrical signals obtained from the first channel Ch1 and the second channel Ch2. This is the conventional common mode feedback.

[0053] As shown in the fourth graph G4, the common mode noise is not sufficiently removed.

[0054] The common mode noise rejection ratio (CMRR) will be further described with reference to Fig. 6. Fig. 6 is an explanatory diagram of the verification results. Fig. 6 shows the common mode noise rejection ratio in each of the three patterns.

[0055] The first pattern (left side) corresponds to the second graph G2 in Figure 5, and shows the common mode noise rejection rate when common mode feedback is performed based on the electrical signal obtained from the first channel Ch1. Of the three patterns, this has the highest common mode noise rejection rate. This allows the electrical signal to be measured with high accuracy.

[0056] The second pattern (center) corresponds to the third graph G3 in Fig. 5, and shows the common mode noise rejection rate when common mode feedback is performed based on the electrical signal obtained from the second channel Ch2. Of the three patterns, this has the lowest common mode noise rejection rate. The second channel Ch2 corresponds to the error electrode.

[0057] The third pattern (right side) corresponds to the fourth graph G4 in Fig. 5, and shows the common mode noise rejection rate when common mode feedback is performed based on the electrical signals obtained from the first channel Ch1 and the second channel Ch2. The rejection of common mode noise is insufficient.

[0058] The above verification shows that this technology can increase the common mode noise rejection rate, which enables the electrical signals detected by the electrodes to be measured with high accuracy.

[0059] [2. Second embodiment of the present technology (example 2 of electrical signal measuring device)] An electrical signal measuring device according to a second embodiment of the present technology will be described with reference to Fig. 7. Fig. 7 is a circuit diagram showing a circuit configuration of the electrical signal measuring device according to the second embodiment. Note that components similar to those in the electrical signal measuring device according to the first embodiment are given the same reference numerals and detailed description thereof will be omitted.

[0060] 7, each of the first active electrode 120 and the second active electrode 220 may include a variable resistor instead of a switch. That is, the first sensing electrode 100 may include a first variable resistor 126. The second sensing electrode 200 may include a second variable resistor 226.

[0061] The first switch changer 125 can change the resistance value of the first variable resistor 126. Specifically, the first switch changer 125 can change the resistance value of the first variable resistor 126 by changing the voltage applied to the first variable resistor 126, for example.

[0062] Similarly, the second switch changeover unit 225 can change the resistance value of the second variable resistor 226 .

[0063] This allows the determination unit 500 to adjust the amount of current flowing through each of the first variable resistor 126 and the second variable resistor 226. For example, when disconnecting the first detection electrode 100 from the circuit, the determination unit 500 instructs the first switch changeover unit 125 to disconnect. The first switch changeover unit 125 increases the resistance value of the first variable resistor 126. This reduces the amount of current flowing through the first variable resistor 126. As a result, the first detection electrode 100 is disconnected from the circuit.

[0064] It should be noted that the first switch changeover unit 125 is provided independently of the first active electrode 120, but for example, the first active electrode 120 may have the first switch changeover unit 125. The same applies to the second switch changeover unit 225.

[0065] [3. Third embodiment of the present technology (example 3 of electrical signal measuring device)] An electrical signal measuring device according to a third embodiment of the present technology will be described with reference to Fig. 8. Fig. 8 is a circuit diagram showing a circuit configuration of the electrical signal measuring device according to the third embodiment. Note that components similar to those of the electrical signal measuring devices according to the first and second embodiments are given the same reference numerals and detailed descriptions thereof will be omitted.

[0066] 8, the determination unit 500 may have a function of switching the on / off state of each of the multiple switches 121 and 221. That is, the electrical signal measuring device 1000 according to this embodiment does not need to have an independent switch switching unit.

[0067] For example, when the first sensing electrode 100 is to be disconnected from the circuit, the determination section 500 changes the first switch 121 from the on state to the off state, thereby disconnecting the first sensing electrode 100 from the circuit.

[0068] [4. Fourth embodiment of the present technology (example 4 of electrical signal measuring device)] An electrical signal measuring device according to a fourth embodiment of the present technology will be described with reference to Fig. 9. Fig. 9 is a circuit diagram showing a circuit configuration of the electrical signal measuring device according to the fourth embodiment. Note that components similar to those of the electrical signal measuring devices according to the first to third embodiments are given the same reference numerals and detailed description thereof will be omitted.

[0069] The determination section 500 may have a function of converting an analog signal into a digital signal. That is, as shown in Fig. 9, the electrical signal measuring device 1000 according to this embodiment does not need to include an independent AD converter.

[0070] The determining section 500 acquires the analog electrical signals detected by each of the multiple electrodes 100 to 300. The determining section 500 converts these analog electrical signals into digital signals and determines the voltage to be used for common mode feedback. Since there is no need to have multiple AD converters, this technology can contribute to miniaturizing devices, for example.

[0071] [5. Fifth embodiment of the present technology (example 5 of electrical signal measuring device)] An electrical signal measuring device according to a fifth embodiment of the present technology will be described with reference to Fig. 10. Fig. 10 is a circuit diagram showing a circuit configuration of the electrical signal measuring device according to the fifth embodiment. Note that components similar to those in the electrical signal measuring devices according to the first to fourth embodiments are given the same reference numerals and detailed description thereof will be omitted.

[0072] 10, the second operational amplifier 421 of the feedback section 400 is connected to each of the multiple instrumentation amplifiers 122 and 222. The feedback section 400 can apply a voltage to the living organism S and also to each of the multiple instrumentation amplifiers 122 and 222. As a result, the electrical signal measuring device 1000 according to this embodiment does not need to include a detection electrode that detects an electrical signal that serves as a reference for the potential from the living organism S. As a result, the present technology can contribute to, for example, miniaturization of devices.

[0073] [6. Sixth embodiment of the present technology (example 6 of electrical signal measuring device)] An electrical signal measuring device according to a sixth embodiment of the present technology will be described with reference to Fig. 11. Fig. 11 is a circuit diagram showing a circuit configuration of the electrical signal measuring device according to the sixth embodiment. Note that components similar to those in the electrical signal measuring devices according to the first to fifth embodiments are given the same reference numerals and detailed description thereof will be omitted.

[0074] 11, the electrical signal measuring device 1000 according to this embodiment does not necessarily have to include an independent AD converter. The determining section 500 can convert an analog signal into a digital signal.

[0075] Furthermore, the electrical signal measuring device 1000 may include a DA converter 600. The DA converter 600 can convert a digital signal into an analog signal.

[0076] The determination unit 500 analyzes the tendency of the contact state information contained in the electrical signals obtained by each of the multiple electrodes 100 to 300. Then, the determination unit 500 determines the voltage to be used for common feedback. This voltage is applied to the living body S via the DA converter 600 and the feedback unit 400, not via each of the multiple electrodes 100 to 300.

[0077] Thereby, each of the first active electrode 120 and the second active electrode 220 does not need to have a switch, etc. As a result, the present technology can contribute to, for example, miniaturization of the device.

[0078] In the electrical signal measuring device 1000 according to this embodiment, the determining section 500 has a function of converting an analog signal into a digital signal, but may be provided with an independent AD converter.

[0079] [7. Seventh embodiment of the present technology (electrical signal measurement system)] An electrical signal measurement system according to a seventh embodiment of the present technology will be described with reference to Fig. 12. Fig. 12 is a block diagram showing a configuration of the electrical signal measurement system according to the seventh embodiment. Note that the electrical signal measurement system according to the seventh embodiment may utilize the techniques according to the first to sixth embodiments. Therefore, the same components as those in the electrical signal measurement devices according to the first to sixth embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0080] As shown in FIG. 12, the electrical signal measurement system 10000 according to this embodiment at least includes a plurality of electrodes 100 to 300, a determination section 500, and a feedback section 400.

[0081] Each of the plurality of electrodes 100 to 300 is disposed at a position in contact with the skin surface of the living body S or at a position close to the skin surface of the living body S. Each of the plurality of electrodes 100 to 300 detects an electrical signal from the living body S.

[0082] The feedback section 400 applies a voltage to the living body S. To explain in more detail, the feedback section 400 reduces the common mode noise by inverting and amplifying a component corresponding to the common mode noise and feeding it back to the living body (common feedback).

[0083] The determination unit 500 is electrically connected to each of the electrodes 100-300 and the feedback unit 400. The determination unit 500 obtains contact state information between the living body S and each of the electrodes 100-300 from the electrical signals detected by each of the electrodes 100-300. Then, the determination unit 500 determines the voltage to be used for the common mode feedback based on the contact state information. The determination unit 500 can be realized by using, for example, a microcomputer or the like.

[0084] The feedback section 400 applies the voltage determined by the determination section 500 to the living body S.

[0085] [8. Eighth embodiment of the present technology (electrical signal measuring method)] An electric signal measuring method according to an eighth embodiment of the present technology will be described with reference to Fig. 13. Fig. 13 is a flowchart showing the procedure of the electric signal measuring method according to the eighth embodiment. Note that the electric signal measuring method according to this embodiment may utilize the techniques according to the first to seventh embodiments.

[0086] As shown in Figure 13, the electrical signal measurement method of this embodiment includes at least the steps of an electrode detecting an electrical signal from a living organism (S100), determining a voltage to be used for common mode feedback based on contact state information between the living organism and the electrode obtained from the electrical signal (S200), and the electrode applying the voltage to the living organism (S300).

[0087] The voltage used for the common mode feedback (S200) can be determined by using, for example, a microcomputer.

[0088] In addition, the configurations described in the above embodiments can be selected or changed to other configurations as appropriate without departing from the spirit of the present technology.

[0089] The effects described in this specification are merely examples and are not limiting, and other effects may also be obtained.

[0090] The present technology can also be configured as follows. [1] An electrode for detecting an electrical signal from a living body; a determination unit that determines a voltage to be used for common mode feedback based on contact state information between the living body and the electrodes obtained from the electrical signal; A feedback unit that applies the voltage to the living body; An electrical signal measuring device comprising at least [2] The electrode is a dry electrode. The electrical signal measuring device described in [1]. [3] The contact state information includes a contact impedance. An electrical signal measuring device according to [1] or [2]. [4] The contact state information includes an amplitude of the electrical signal. The electrical signal measuring device according to any one of [1] to [3]. [5] the determination unit compares the contact state information with a predetermined threshold value to determine the voltage; The electrical signal measuring device according to any one of [1] to [4]. [6] the determination unit analyzes a trend of the contact state information to determine the voltage. The electrical signal measuring device according to any one of [1] to [5]. [7] The electrode has a switch. The electrical signal measuring device according to any one of [1] to [6]. [8] The electrode has a variable resistance. The electrical signal measuring device according to any one of [1] to [7]. [9] An electrode for detecting an electrical signal from a living body; a determination unit that determines a voltage to be used for common mode feedback based on contact state information between the living body and the electrodes obtained from the electrical signal; A feedback unit that applies the voltage to the living body; An electrical signal measurement system comprising at least

[10] The electrodes detect electrical signals from a living body; determining a voltage to be used for common mode feedback based on contact state information between the living body and the electrodes obtained from the electrical signal; The electrodes apply the voltage to the living body; An electrical signal measuring method comprising at least the steps of: [Explanation of symbols]

[0091] S: Living organism 1000: Electrical signal measuring device 100, 200, 300: Electrode 121, 221: Switch 126, 226: Variable resistor 400: Return Section 500: Judgment section 600: DA converter 10000: Electrical signal measurement system S100: Detecting electrical signals from the living body using electrodes S200: Determining the voltage used for common mode feedback S300: Applying voltage to living organisms

Claims

1. An electrode for detecting an electrical signal from a living body; a determination unit that compares a contact impedance included in contact state information between the living body and the electrodes, which is obtained from the electrical signal, or an amplitude of the electrical signal with a predetermined threshold value to determine a voltage to be used for common mode feedback; A feedback unit that applies the voltage to the living body; At least one of the following is provided: An electrical signal measuring device, wherein an output terminal of an operational amplifier of the feedback section is connected to an input terminal of an instrumentation amplifier of the electrode.

2. The electrode is a dry electrode. The electrical signal measuring device according to claim 1 .

3. The electrode has a switch. The electrical signal measuring device according to claim 1 .

4. The electrode has a variable resistance. The electrical signal measuring device according to claim 1 .

5. The determination unit has a function of converting an analog signal into a digital signal, a DA converter connected between the determination unit and the feedback unit converts a digital signal output by the determination unit into an analog signal; an output terminal of the DA converter is connected to an input terminal of an operational amplifier included in the feedback section; The electrical signal measuring device according to claim 1 .

6. An electrode for detecting an electrical signal from a living body; a determination unit that compares a contact impedance included in contact state information between the living body and the electrodes, which is obtained from the electrical signal, or an amplitude of the electrical signal with a predetermined threshold value to determine a voltage to be used for common mode feedback; A feedback unit that applies the voltage to the living body; At least one of the following is provided: An electrical signal measurement system, wherein an output terminal of an operational amplifier of the feedback section is connected to an input terminal of an instrumentation amplifier of the electrode.

7. The electrodes detect electrical signals from a living body; determining a voltage to be used for common mode feedback by comparing a contact impedance included in contact state information between the living body and the electrodes, which is obtained from the electrical signal, or an amplitude of the electrical signal with a predetermined threshold; Connecting an output terminal of an operational amplifier for applying the voltage to the living body to an input terminal of an instrumentation amplifier of the electrode; The electrodes apply the voltage to the living body; An electrical signal measuring method comprising at least the steps of:

Images