Biopotential electrode body and biopotential sensor

Abstract

To provide a biopotential electrode body that has strong mechanical strength and is suitable for obtaining a greater amount of biological information.SOLUTION: A biopotential electrode body has a plurality of conductor portions each including a contact surface that can contact a living body, and one or more insulator portions that mutually electrically insulate the plurality of conductor portions. The conductor portions include a first elastic resin and a plurality of first particles embedded in the first elastic resin. The insulator portions include a second elastic resin and a plurality of second particles embedded in the second elastic resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0005]

[0001] The present disclosure relates to a bioelectric potential sensor that detects bioelectric signals by contacting a living body, and a bioelectric potential electrode body used therefor.

Background Art

[0002] An earphone-type bioelectric potential sensor for detecting bioelectric signals such as brain waves, heartbeats, or pulses has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the earpiece portion that contacts the outer ear is made of a conductive material, and this earpiece portion is used as an electrical contact with the living body.

[0005] By the way, in a bioelectric potential sensor, it is desirable to have excellent durability and to obtain more bioinformation.

[0006] Therefore, a bioelectric potential sensor having high mechanical strength and suitable for obtaining more bioinformation, and a bioelectric potential electrode used therefor are desired.

Means for Solving the Problems

[0007] A biopotential electrode body according to one embodiment of the present disclosure comprises a plurality of conductive portions, each having a contact surface that can come into contact with a living organism, and one or more insulating portions that electrically insulate the plurality of conductive portions from each other. The conductive portions include a first elastic resin and a plurality of first particles embedded in the first elastic resin. The insulating portions include a second elastic resin and a plurality of second particles embedded in the second elastic resin.

[0008] A biopotential sensor according to one embodiment of the present disclosure comprises the biopotential electrode body described above.

[0009] In one embodiment of the biopotential electrode and biopotential sensor of this disclosure, since it includes a plurality of conductive portions that are insulated from each other, it is possible to detect the potential at multiple locations in a living body. Furthermore, since the conductive portions include a plurality of first particles and the insulating portions include a plurality of second particles, delamination between the conductive portions and the insulating portions is less likely to occur. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing the overall configuration of an electrode unit having a pair of electrode bodies according to the first embodiment of this disclosure. [Figure 2] Figure 1 is a schematic perspective view showing the appearance of the electrode body. [Figure 3] This is a schematic cross-sectional view showing another cross-section of the electrode body shown in Figure 1. [Figure 4] Figure 1 is a cross-sectional view showing the details of the electrode body. [Figure 5] This is a cross-sectional view showing the details of the first particle contained in the electrode body shown in Figure 1. [Figure 6] This is a cross-sectional view showing details of other first particles contained in the electrode body shown in Figure 1. [Figure 7] This is a cross-sectional view showing an example of the configuration of an electrode body according to a first modification of the first embodiment of the present disclosure. [Figure 8] This is a cross-sectional view showing an example of the configuration of an electrode body according to a second modification of the first embodiment of the present disclosure. [Figure 9A]It is a perspective view schematically showing an overall configuration example of a bioelectric potential sensor according to a second embodiment of the present disclosure. [Figure 9B] It is an exploded perspective view of the bioelectric potential sensor shown in FIG. 9A. [Figure 10] It is a block diagram schematically showing an overall configuration example of the bioelectric potential sensor shown in FIG. 9A. [Figure 11] It is a cross-sectional view showing a configuration example of an electrode body according to a first modification of the second embodiment of the present disclosure. [Figure 12] It is a cross-sectional view showing a configuration example of an electrode body according to a second modification of the second embodiment of the present disclosure. [Figure 13] It is a block diagram schematically showing an overall configuration example of a bioelectric potential sensor according to a third modification of the second embodiment of the present disclosure. [Figure 14] It is a block diagram schematically showing an overall configuration example of a bioelectric potential sensor according to a fourth modification of the second embodiment of the present disclosure. [Figure 15] It is a schematic diagram showing an example of using the electrode body shown in FIG. 1 for a head-mounted display. [Figure 16] It is a schematic diagram showing an example of using the electrode body shown in FIG. 1 for a headband. [[ID=​​​​​​​ 1.1. Configuration example 1.2. Manufacturing method 1.3. Function and effect 1.4. Variation example 2. Second embodiment (bioelectric potential sensor) 2.1. Configuration example 2.2. Function and effect 2.3. Variation example 3. Other variation examples

[0013] <0. Background Hitherto, when measuring bioelectric potentials such as electroencephalogram or measuring bioimpedance such as skin electrical activity, wet electrodes have often been used. A wet electrode is, for example, an electrode that reduces the contact impedance with a living body by using a gel for measurement, physiological saline, etc. However, in consumer applications, the use of wet electrodes has often been avoided from the viewpoints of dirt due to the adhesion of gels, etc., changes over time of gels, etc., or the annoyance of measurement preparation. Therefore, recently, measuring devices using dry electrodes have begun to be proposed (see, for example, "Dry EEG Electrodes" Sensors, 14, 12847 (2014), etc.).

[0014] Regarding the materials of such dry electrodes as well, various proposals have been made. For example, in Japanese Patent Application No. 2010-247047, a nitrile rubber composition in which conductive particles such as carbon are mixed with an elastomer such as rubber has been proposed. Since the nitrile rubber composition is rich in flexibility, it is expected that the comfort during wearing will be improved by using this as the material of the dry electrode.

[0015] On the other hand, in recent years, efforts have been made to obtain useful information from the human body by performing electrical measurements (see, for example, "Hearables: Multimodal physiological in-ear sensing" Scientific Reports, 7, 6948 (2017), and "Unobtrusive ambulatory EEG using a smartphone and flexible printed electrodes around the ear" Scientific Reports, 5, 16743 (2015)). In such cases, electrodes are made to come into contact with a limited area of ​​the skin surface of the human body, such as the outer ear or the area surrounding the outer ear.

[0016] For example, in the aforementioned Patent Document 1, a conductive resin is used for the electrical contact with the inner surface of the external auditory canal. However, in earphone-type biopotential sensors like the one in Patent Document 1, the electrodes are in contact with a limited skin surface, namely the inner surface of the external auditory canal. As a result, the biometric information obtained is limited to a single point.

[0017] Therefore, this disclosure provides a biopotential sensor suitable for obtaining more biological information, and a biopotential electrode body used therein.

[0018] <1. First Embodiment> [1.1. Example Configuration] (Electrode Unit 1) First, an electrode unit 1 as a biopotential electrode body according to the first embodiment of this disclosure will be described with reference to Figures 1 to 3. Figure 1 is a first cross-sectional view schematically showing an example of the overall configuration of the electrode unit 1. Figure 2 is a perspective view schematically showing the appearance of the electrodes 10L and 10R. Figure 3 is a second cross-sectional view of the electrodes 10L and 10R, showing a cross-section perpendicular to the cross-section shown in Figure 1.

[0019] As shown in Figure 1, the electrode unit 1 has a pair of electrodes 10L and 10R. As shown in Figures 1 to 3, the pair of electrodes 10L and 10R have substantially the same structure. Therefore, in the following, we will describe electrode 10L of the pair of electrodes 10L and 10R. In this specification, when it is not necessary to distinguish between the pair of electrodes 10L and 10R, they may simply be referred to as electrode 10.

[0020] (Electrode body 10L) The electrode body 10L has a plurality of conductive portions and one or more insulating portions. The plurality of conductive portions are specifically, for example, a first conductive portion 11L and a second conductive portion 12L. The one or more insulating portions are specifically, for example, a first insulating portion Z1L and a second insulating portion Z2L. The first conductive portion 11L and the second conductive portion 12L, as well as the first insulating portion Z1L and the second insulating portion Z2L, together form a substantially cylindrical cylindrical structure including a through hole 10HL. The cylindrical structure formed by the first conductive portion 11L and the second conductive portion 12L, as well as the first insulating portion Z1L and the second insulating portion Z2L, is supported, for example, by a support 13L inserted through the through hole 10HL. The first conductive portion 11L, the first insulating portion Z1L, the second conductive portion 12L, and the second insulating portion Z2L are arranged alternately in the circumferential direction of the above-described cylindrical structure. The first conductive portion 11L and the first insulating portion Z1L are connected at interface K1L. The first insulating portion Z1L and the second conductive portion 12L are connected at interface K2L. The second conductive portion 12L and the second insulating portion Z2L are connected at interface K3L. The second insulating portion Z2L and the first conductive portion 11L are connected at interface K4L. Therefore, the first conductive portion 11L and the second conductive portion 12L are electrically insulated from each other by the first insulating portion Z1L and the second insulating portion Z2L.

[0021] (1st conductor part 11L) The first conductive portion 11L has a two-layer structure consisting of a first core portion C1L and a first elastic portion E1L. The first core portion C1L and the first elastic portion E1L are stacked radially in the cylindrical structure. The first core portion C1L is located on the inside of the cylindrical structure. The first elastic portion E1L is located on the outside of the cylindrical structure. The first elastic portion E1L includes a first surface 11SL opposite to the through hole 10HL. The first surface 11SL is a contact surface that can come into contact with the surface of a living organism, such as the skin surface of the human body. The first core portion C1L mainly contains a highly conductive metallic material such as Au (gold), Ag (silver), or Cu (copper) as its constituent material. The first core portion C1L is the portion that comes into contact with the first electrode 131 (see Figure 4 below) of the support 13L inserted into the through hole 10HL.

[0022] (Second conductor part 12L) The second conductive portion 12L has substantially the same configuration as the first conductive portion 11L described above. That is, the second conductive portion 12L has a two-layer structure consisting of a second core portion C2L and a second elastic portion E2L. The second core portion C2L and the second elastic portion E2L are stacked radially in the cylindrical structure. The second core portion C2L is located on the inside of the cylindrical structure. The second elastic portion E2L is located on the outside of the cylindrical structure. The second elastic portion E2L includes a second surface 12SL opposite to the through hole 10HL. The second surface 12SL is a contact surface that can come into contact with the surface of a living organism, for example, the surface of human skin. The second core portion C2L mainly contains a highly conductive metallic material such as Au (gold), Ag (silver), or Cu (copper) as its constituent material. The second core portion C2L is the portion that comes into contact with the second electrode 132 (see Figure 4 below) of the support 13L inserted into the through hole 10HL.

[0023] (First elastic section E1L and second elastic section E2L) Figure 4 is a cross-sectional view showing details of the electrode body 10L shown in Figure 1. As shown in Figure 4, the first elastic part E1L and the second elastic part E2L each contain a first elastic resin 14 and a plurality of first particles 15 embedded in the first elastic resin 14. The first elastic resin 14 is, for example, an insulating resin. In contrast, the first particles 15 are, for example, conductive particles. Because the conductive first particles 15 are dispersed and contained in the first elastic resin 14, the first elastic part E1L and the second elastic part E2L each become conductive. The first elastic part E1L and the second elastic part E2L each contain, for example, 30 wt% of the first particles 15.

[0024] The average primary particle diameter of the first particles 15 is preferably in the range of 10 to 100 nm. This is because the first particles 15 are more easily dispersed homogeneously in the first elastic resin 14. When the first particles 15 are conductive particles, the conductivity of the first elastic part E1L and the second elastic part E2L is improved by the more homogeneous dispersion of the first particles 15 in the first elastic resin 14, which is preferable.

[0025] Furthermore, the average secondary particle diameter of the first particle 15 is preferably in the range of 30 to 500 nm. By having a secondary particle size within the above range for the base material particles 111, the conductive particles 103 become more easily dispersed in the base material resin layer 101, making it possible to further improve measurement accuracy.

[0026] Here, the average primary particle diameter and average secondary particle diameter of the substrate particles 111 can be measured by direct observation using a transmission electron microscope (TEM) or by particle size measurement using dynamic light scattering.

[0027] Figure 5 is a schematic diagram showing an example of the cross-sectional structure of the first particle 15. As shown in Figure 5, the first particle 15 has a base particle 151 and a surface treatment area 152. The base particle 151 is, for example, a conductor or insulator including a surface 151S. In Figure 5, a spherical base particle 151 is schematically shown, but in this disclosure, the shape of the base particle is not limited to a sphere, and may be ellipsoidal or have an uneven surface. The surface treatment area 152 is, for example, a conductor that covers or replaces at least a part of the surface 151S of the base particle 151. Furthermore, the first particle 15 does not need to have a surface treatment area 152 if the base particle 151 is conductive. Moreover, it is preferable that the surface treatment area 152 is present over the entire surface 151S of the base particle 151, as shown in Figure 5. However, the first particle of this disclosure also includes, for example, the first particle 15A in which the surface treatment 152 is selectively present only on a portion of the surface 151S of the substrate particle 151, as shown in Figure 6.

[0028] The base particles 151 may be, for example, carbon particles or metal particles. These carbon particles and metal particles are conductive themselves, making it easier to ensure the conductivity of the first elastic part E1L and the second elastic part E2L. The metal particles as base particles 151 are composed of a metal consisting of at least one of gold (Au), silver (Ag), and copper (Cu). When the base particles 151 are metal particles, the surface treatment 152 may be a metal compound that covers at least a portion of the surface 151S of the base particles 151. The metal compound as surface treatment 152 is, for example, a sulfide, selenide, or chloride of at least one of gold (Au), silver (Ag), and copper (Cu).

[0029] The carbon particles as the base material particles 151 are, for example, particles made of various carbon compounds. Specifically, the carbon particles are, for example, particles of carbon black (graphite), carbon nanotubes, and graphene. Alternatively, the carbon particles may be granular forms of flakes or fibers of each of the materials: carbon black (graphite), carbon nanotubes, and graphene.

[0030] The base particles 151 may be, for example, polymer particles. Polymer particles are particles made from various resin compositions, and examples include particles of polyphenylene sulfide (PPS) resin, polyethylene terephthalate (PET) resin, polyethersulfone (PES) resin, polyamide-imide (PAI) resin, acrylic resin, polyvinylidene difluoride (PVDF) resin, epoxy resin, polylactic acid resin, nylon resin, urethane resin, and the like.

[0031] The first particle 15 may, for example, have an organic conductive polymer as a surface treatment 152 when the base particle 151 is an insulating particle. The organic conductive polymer as the surface treatment 152 includes at least one from the group consisting of PEDOT-PSS, polypyrrole, polyacetylene, polyphenylenevinylene, polythiophene, polythiol, and polyaniline, and their analogs. Each of the above organic conductive polymers may be used individually or in combination as the surface treatment 152. When an organic conductive polymer is used as the surface treatment 152, various binder resins such as water-soluble acrylic resin, water-soluble urethane resin, water-soluble polyester alkyd, and water-soluble amino resin may be mixed with the organic conductive polymer. This is to more reliably coat the surface 151S of the base particle 151 and improve the adhesion between the base particle 151 and the surface treatment 152. Note that the organic conductive polymer as the surface treatment 152 can also be used when the base particle 151 is a conductive particle. Furthermore, in the first particle 15, the surface treatment portion 152 may be a mixture of a portion containing an organic conductive polymer and a portion containing a metal compound.

[0032] (First insulating portion Z1L and second insulating portion Z2L) As shown in Figure 4, the first insulator portion Z1L and the second insulator portion Z2L each contain a second elastic resin 16 and a plurality of second particles 17 embedded in the second elastic resin 16. The second elastic resin 16 is, for example, an insulating resin. The constituent material of the second elastic resin 16 may be substantially the same as the constituent material of the first elastic resin 14. The second particles 17 are, for example, insulating particles. As the second particles 17, titanium oxide such as TiO2 can be used. The first insulator portion Z1L and the second insulator portion Z2L contain, for example, 20 wt% of the second particles 17.

[0033] The first elastic resin 14 and the second elastic resin 16 are resins mainly composed of a predetermined resin material, rubber, or elastomer. More specifically, the first elastic resin 14 and the second elastic resin 16 are solidified or cured products of resin components mainly composed of a predetermined resin material, rubber, or elastomer. Here, "solidified product" simply means a product in which the resin component itself has solidified, and "cured product" means a product in which the resin component has been cured by adding various curing agents to it. Furthermore, "main component" means a component that is present in 50 parts by mass or more of 100 parts by mass of the total resin component, and "resin component" does not include non-resin components such as crosslinking agents.

[0034] The Shore hardness (Shore A hardness) of the first elastic resin 14 and the second elastic resin 16 is preferably 70 HS or less, for example. This is because if the Shore A hardness of the first elastic resin 14 is 70 HS or less, the Shore A hardness of the first conductive portion 11L and the second conductive portion 12L, which are formed by kneading the first particles 15 into the first elastic resin 14, can be set to 80 HS or less. Similarly, if the Shore A hardness of the second elastic resin 16 is 70 HS or less, the Shore A hardness of the first insulating portion Z1L and the second insulating portion Z2L, which are formed by kneading the second particles 17 into the second elastic resin 16, can be set to 80 HS or less. By setting the Shore A hardness of the first conductive portion 11L and the second conductive portion 12L to 80 HS or less, it becomes easier to follow the movement of the living body, and the adhesion to the living body can be further improved. Furthermore, comfort is ensured when the electrode body 10L is attached to the human body as a living organism. The Shore A hardness of the first elastic resin 14 and the second elastic resin 16 is measured in accordance with the method described in JIS K6253:2012.

[0035] The electrode body 10L has a first conductive portion 11L including a first surface 11SL that comes into contact with the living body, and a second conductive portion 12L including a second surface 12SL, both having the first elastic resin 14 as described above. Therefore, it is possible to maintain sufficient adhesion between the electrode body 10L and the living body.

[0036] Examples of the first elastic resin 14 and the second elastic resin 16 include at least one thermoplastic resin selected from the group consisting of polyvinyl chloride resin, polypropylene resin, polyethylene resin, polyurethane resin, polyacetal resin, polyamide resin, and polycarbonate resin, as well as copolymers thereof.

[0037] Furthermore, examples of rubbers to be applied to the first elastic resin 14 and the second elastic resin 16 include natural rubber or synthetic rubber. Examples of synthetic rubbers include diene-based rubbers such as styrene-butadiene rubber and isoprene rubber.

[0038] Furthermore, examples of elastomers applied to the first elastic resin 14 and the second elastic resin 16 include thermosetting elastomers, which include one selected from the group consisting of silicone resins and polyurethane resins.

[0039] The resin materials, rubbers, and elastomers mentioned above are merely examples, and various other known resin materials, rubbers, and elastomers can be used. Furthermore, the first elastic resin 14 and the second elastic resin 16 may contain various additives, such as pigments and colorants.

[0040] As shown in Figure 4, the through-hole 10HL is provided so that the support 13L can be inserted into it. The support 13L is a member having a shape that can be press-fitted into the through-hole 10HL, for example, a substantially cylindrical or substantially columnar shape. The support 13L includes a first electrode 131, a second electrode 132, and an insulating portion 133. The first electrode 131 is the portion that contacts the first core portion C1L. The second electrode 132 is the portion that contacts the second core portion C2L. The insulating portion 133 is an insulator that electrically separates the first electrode 131 and the second electrode 132.

[0041] (Electrode body 10R) The configuration of electrode body 10R is substantially the same as the configuration of electrode body 10L described above. Specifically, for example, the configuration of electrode body 10R can be explained by substituting the first conductive portion 11L, second conductive portion 12L, first insulating portion Z1L, second insulating portion Z2L, through hole 10HL, interface K1L, interface K2L, interface K3L, interface K4L, first core portion C1L, first elastic portion E1L, first surface 11SL, second core portion C2L, second elastic portion E2L, and second surface 12SL of electrode body 10L with the first conductive portion 11R, second conductive portion 12R, first insulating portion Z1R, second insulating portion Z2R, through hole 10HR, interface K1R, interface K2R, interface K3R, interface K4R, first core portion C1R, first elastic portion E1R, first surface 11SR, second core portion C2R, second elastic portion E2R, and second surface 12SR shown in Figure 4. As shown in Figure 4, a support 13R is inserted into the through hole 10HR. The configuration of the support 13R is substantially the same as that of the support 13L.

[0042] In the following explanation, the first conductive portion 11L and the first conductive portion 11R may be collectively referred to as the first conductive portion 11. Similarly, the second conductive portion 12L and the second conductive portion 12R may be collectively referred to as the second conductive portion 12. Furthermore, the first insulator portion Z1L and the first insulator portion Z1R may be collectively referred to as the first insulator portion Z1. Furthermore, the second insulator portion Z2L and the second insulator portion Z2R may be collectively referred to as the second insulator portion Z2. Furthermore, the through hole 10HL and the through hole 10HR may be collectively referred to as the through hole 10H. Furthermore, interfaces K1L, K2L, K3L, K4L, K1R, K2R, K3R, and K4R may be collectively referred to as interface K. In addition, the first elastic section E1L and the first elastic section E1R may be collectively referred to as the first elastic section E1. The first surface 11SL and the first surface 11SR may be collectively referred to as the first surface 11S. In addition, the second elastic section E2L and the second elastic section E2R may be collectively referred to as the second elastic section E2. In addition, the second surface 12SL and the second surface 12SR may be collectively referred to as the second surface 12S.

[0043] [1.2. Manufacturing method] (Method for manufacturing electrode body 10) Next, the manufacturing method of the electrode body 10 of this embodiment will be briefly described. The electrode body 10 can be manufactured using so-called injection molding technology. The manufacturing process includes, for example, the first to third steps. The first step is the process of manufacturing first particles 15 and second particles 17. The second step is the process of kneading the manufactured first particles 15 and second particles 17 into a first elastic resin 14 and a second elastic resin 16, respectively, to manufacture a first kneaded resin composition and a second kneaded resin composition, respectively. The third step includes the third step of simultaneously injection molding the first kneaded resin composition and the second kneaded resin composition to manufacture an electrode body 10 in which the first conductive portion 11 and the second conductive portion 12 are alternately arranged and integrated.

[0044] Here, the method for producing the first particles 15 and the second particles 17 is not particularly limited. For example, the first particles 15 can be produced by known methods such as permeating a compound for forming a surface treatment 152 into a container filled with base particles 151, or by adding base particles 151 to a solution containing a compound for forming a surface treatment 152 and stirring the solution. The method for producing the first kneaded resin composition and the second kneaded resin composition is also not particularly limited and can be carried out by known methods. The average particle size of the secondary aggregates (aglomerates) of the first particles 15 when kneading the first particles 15 into the first elastic resin 14 is, for example, about 1 μm to 200 μm.

[0045] Furthermore, regarding the third step described above, it is possible to manufacture electrode bodies 10 of any size and shape by methods such as two-color molding, in accordance with various known injection molding technologies.

[0046] [1.3. Effects] The electrode body 10 of this embodiment has a first conductive portion 11 and a second conductive portion 12, and a first insulating portion Z1 and a second insulating portion Z2. The first conductive portion 11 and the second conductive portion 12 each include a first surface 11S and a second surface 12S, respectively, which are contact surfaces that can come into contact with living tissue. Here, the first conductive portion 11 and the second conductive portion 12 are electrically insulated by the first insulating portion Z1 and the second insulating portion Z2. Therefore, the potential of living tissue can be detected at the contact point between the first surface 11S of the first conductive portion 11 and living tissue, and at the contact point between the second surface 12S of the second conductive portion 12 and living tissue. In other words, the electrode body 10 can be used to detect the potential at multiple locations on living tissue.

[0047] Furthermore, in the electrode body 10 of this embodiment, the first conductive portion 11 includes a first elastic portion E1, and the second conductive portion 12 includes a second elastic portion E2. Therefore, good adhesion between the first surface 11S and the living body, and between the second surface 12S and the living body can be maintained.

[0048] Furthermore, in the electrode body 10, the first elastic portion E1 and the second elastic portion E2 each contain the first elastic resin 14 and a plurality of first particles 15. For this reason, by making the first particles 15 conductive, for example, the first elastic resin 14 can be made of an insulating resin. Therefore, compared to the case in which the first elastic resin 14 is formed from a conductive resin, processability is improved, and the first elastic portion E1 and the second elastic portion E2 of a wider variety of shapes can be formed with higher precision.

[0049] Furthermore, in the electrode body 10, the first insulating portion Z1 and the second insulating portion Z2 contain the second elastic resin 16 and a plurality of second particles 17. Therefore, compared to the case where the first insulating portion Z1 and the second insulating portion Z2 do not contain the second particles 17, delamination is less likely to occur at each interface K between the first conductive portion 11 and the second conductive portion 12 and the first insulating portion Z1 and the second insulating portion Z2. This is because the stress concentration at each interface K is alleviated because the first conductive portion 11 and the second conductive portion 12 each contain the first particles 15, and the first insulating portion Z1 and the second insulating portion Z2 contain the second particles 17. Thus, the mechanical strength of the electrode body 10 is improved, and its long-term reliability is enhanced.

[0050] In particular, by making the constituent materials of the first elastic resin 14 and the second elastic resin 16 substantially the same, stress concentration at each interface K is further reduced. As a result, the mechanical strength of the electrode body 10 is further improved, and its long-term reliability is further enhanced.

[0051] Furthermore, in the electrode body 10, the first conductive portion 11, the first insulating portion Z1, the second conductive portion 12, and the second insulating portion Z2 are arranged alternately in the circumferential direction of the cylindrical structure. Therefore, the first conductive portion 11 and the second conductive portion 12 can be brought into contact with the measurement site of the living body, respectively. For example, when the electrode body 10 is attached to the external auditory canal of a person to detect the brainwaves (EEG) of the person, the first surface 11S of the first conductive portion 11 may be brought into contact with the part of the inner surface of the external auditory canal on the top of the head side where the EEG intensity is relatively strong, and the second surface 12S of the second conductive portion 12 may be brought into contact with the part of the inner surface of the external auditory canal on the neck side where the EEG intensity is relatively weak. In that case, the potential difference between the potential of the part on the top of the head side and the potential of the part on the neck side can be measured.

[0052] [1.4. Variant Example] (Extreme variation 1-1) Figure 7 is a cross-sectional view showing an example configuration of an electrode body 10A according to a first modification (modification 1-1) of the first embodiment of the present disclosure. In the electrode body 10 of the first embodiment described above, the first elastic portion E1 and the second elastic portion E2 are solid bodies that do not contain cavities or air bubbles. In contrast, the electrode body 10A of modification 1-1 includes cavities V1 and V2 inside the first elastic portion E1 and the second elastic portion E2, respectively. According to the electrode body 10A of modification 1-1, since cavities V1 and V2 are included, the first conductive portion 11 and the second conductive portion 12 have even higher elasticity. Therefore, the adhesion between the first surface 11S and the living body, and the adhesion between the second surface 12S and the living body can be maintained even better. Cavities may also be provided inside the first insulating portion Z1 and the second insulating portion Z2, respectively.

[0053] (Variations 1-2) Figure 8 is a cross-sectional view showing an example configuration of an electrode body 10B according to a second modification (modification 1-2) of the first embodiment of the present disclosure. The electrode body 10 of the first embodiment has a cylindrical structure. In the electrode body 10, a conductive portion and an insulating portion extend radially from the center of the cylindrical structure, respectively. In contrast, in the electrode body 10B as modification 1-2, a plurality of conductive portions are separated in the axial direction of the cylindrical structure by the insulating portion. That is, in the electrode body 10B of modification 1-2, a first conductive portion 11, an insulating portion Z, and a second conductive portion 12 are arranged in order in the Z-axis direction indicated by the arrow. Here, the insulating portion Z has the same configuration as, for example, at least one of the first insulating portion Z1 and the second insulating portion Z2. In the electrode body 10B of modification 1-2, the first conductive portion 11 and the second conductive portion 12 are each provided without interruption over the entire circumference in the circumferential direction of the cylindrical structure. Therefore, for example, when attaching the electrode body 10B to the external auditory canal of a human body, it is not necessary to align the circumferential position of the cylindrical structure with the position on the inner surface of the external auditory canal. Furthermore, as will be described later, it is suitable for using the first conductive portion 11 as a terminal for detecting biopotential and the second conductive portion 12 as a reference terminal or ground terminal.

[0054] <2. Second Embodiment> [2.1. Example Configuration] (Bioelectric potential sensor 100) Next, with reference to Figures 9A to 10, a biopotential sensor 100 according to the second embodiment of this disclosure will be described. Figure 9A is a schematic perspective view showing an example of the overall configuration of the biopotential sensor 100. Figure 9B is an exploded perspective view of the biopotential sensor 100. Figure 10 is a block diagram schematically showing an example of the overall configuration of the biopotential sensor 100.

[0055] The biopotential sensor 100 is mounted on a wireless earphone. As shown in Figure 9A, the biopotential sensor 100 has electrode bodies 10L and 10R and main bodies 30L and 30R. Figure 9B shows the electrode bodies 10L and 10R removed from the main bodies 30L and 30R. As shown in Figure 9B, the main body 30L includes a base 31L and a support 13L provided on the base 31L. The main body 30R includes a base 31R and a support 13R provided on the base 31R. The electrode bodies 10L and 10R have the configuration described in the first embodiment above. The electrode bodies 10L and 10R are supported by support 13L and 13R which are inserted through through holes 10HL and 10HR, respectively.

[0056] As shown in Figure 10, the biopotential sensor 100 includes, for example, terminals T1 to T3, preamplifiers 51 to 53, a differential amplifier 54, an analog-to-digital converter (ADC) 55, and a signal processing device 56. Terminals T1 to T3 are included in electrode bodies 10L and 10R. The preamplifiers 51 to 53, the differential amplifier 54, the ADC 55, and the signal processing device 56 are included in the main body 30L and 30R. The signal processing device 56 includes, for example, a signal processing unit 561, a storage unit 562, and a communication unit 563. The signal processing unit 561 includes, for example, a digital signal processor (DSP). The storage unit 562 includes, for example, a semiconductor memory such as DRAM. The communication unit 563 includes, for example, a communication device compatible with a short-range wireless communication standard such as Bluetooth (a registered trademark of Bluetooth SIG, Inc.). The signal processing device 56 can be connected to an external device 57, such as a personal computer (PC), wirelessly or wired. The external device 57 includes, for example, an arithmetic unit 571 such as a central processing unit (CPU).

[0057] Terminals T1 to T3 are each designed to contact different parts of the skin surface SS of a living organism. The biopotential sensor 100 can be used to measure the brain waves of a human body by, for example, attaching electrode body 10L to the left external auditory canal of the human body and electrode body 10R to the right external auditory canal of the human body. In this case, in the biopotential sensor 100, for example, the first conductive portion 11L of electrode body 10L and the first conductive portion 11R of electrode body 10R are used as terminal T1. The first surface 11SL of the first conductive portion 11L and the first surface 11SR of the first conductive portion 11R are preferably in contact with the part of the inner surface of the left and right external auditory canals that is on the top of the head side where the EEG intensity is relatively strong. In addition, the second conductive portion 12L of electrode body 10L is used as terminal T2. In this case, the second surface 12SL of the second conductive portion 12L is preferably in contact with the part of the inner surface of the external auditory canal that is on the neck side where the EEG intensity is relatively weak. Terminal T2 is, for example, a reference terminal, which detects a reference potential for measuring the difference between the potential detected at terminal T1 and the reference potential. Furthermore, the second conductive portion 12R of the electrode body 10R is used as, for example, terminal T3. In this case, the second surface 12SR of the second conductive portion 12R is preferably in contact with the neck-side portion of the inner surface of the external auditory canal where the EEG intensity is relatively weak. Terminal T3 is, for example, a ground terminal.

[0058] [2.2. Effects] As described above, the biopotential sensor 100 of this embodiment has electrode bodies 10L and 10R as described in the first embodiment, so it can be used to detect the potential at multiple locations in the body. For example, by bringing the first surface 11S of the first conductive portion 11 into contact with the part of the inner surface of the external auditory canal on the top of the head where the EEG intensity is relatively strong, and bringing the second surface 12S of the second conductive portion 12 into contact with the part of the inner surface of the external auditory canal on the neck side where the EEG intensity is relatively weak, the potential difference between the potential at the top of the head side and the potential at the neck side can be easily measured. This makes it possible to detect the brain waves of the human body with greater accuracy. In addition, since the electrode body 10 has excellent mechanical strength, the long-term reliability of the biopotential sensor 100 is improved.

[0059] [2.3. Variant] (Variation 2-1) Figure 11 is a schematic diagram showing an example of the cross-sectional configuration of the electrode unit 1C of a biopotential sensor 100A according to a first modified example (modification 2-1) of the second embodiment of the present disclosure. In the biopotential sensor 100 of the second embodiment described above, electrode bodies 10L and 10R having substantially the same configuration are used. In contrast, the electrode unit 1C of modification 2-1 includes electrode bodies 10CL and 10CR having different configurations. Specifically, as shown in Figure 11, for example, in the electrode body 10CR that is attached to the right external auditory canal, a first conductive portion 11R is provided so as to occupy the entire circumferential direction of the cylindrical structure. On the other hand, in the electrode body 10CL that is attached to the left external auditory canal, the first conductive portion 11L, the first insulating portion Z1L, the second conductive portion 12L, and the second insulating portion Z2L are arranged alternately in the circumferential direction of the cylindrical structure. In electrode body 10CL, the volume ratio of the first conductive portion 11L to the entire electrode body 10L is higher than the volume ratio of the second conductive portion 12L to the entire electrode body 10L. The support 13L is provided with a first electrode 131 corresponding to the first conductive portion 11L and a second electrode 132 corresponding to the second conductive portion 12L. The support 13R is provided with a first electrode 131 corresponding to the first conductive portion 11R.

[0060] In the biopotential sensor 100A of modified example 2-1, for example, the first conductive portion 11R of electrode body 10CR of electrode body unit 1C can be used as terminal T1 for electroencephalogram detection, the first conductive portion 11L of electrode body 10CL can be used as terminal T2 for reference, and the second conductive portion 12L of electrode body 10CL can be used as terminal T3 for grounding.

[0061] (Variation 2-2) Figure 12 is a schematic diagram showing an example of a cross-sectional configuration of an electrode body 10D of a biopotential sensor 100B according to a second modification (modification 2-2) of the second embodiment of the present disclosure. In the second embodiment described above, an electrode body unit 1 including a pair of electrode bodies 10L and 10R is used. In contrast, in the biopotential sensor 100B of modification 2-2, one electrode body 10D is assigned to terminals T1 to T3. When the biopotential sensor 100B detects, for example, brain waves of a human body, the electrode body 10D is attached to the right or left external auditory canal. As shown in Figure 12, the electrode body 10D has three conductive parts, namely the first to third conductive parts 11 to 13. The electrode body 10D further has first to third insulating parts Z1 to Z3 provided to electrically separate the first to third conductive parts 11 to 13 from each other. The support 13 is provided with a first electrode 131 corresponding to the first conductive portion 11, a second electrode 132 corresponding to the second conductive portion 12, and a third electrode 134 corresponding to the third conductive portion 13.

[0062] According to the biopotential sensor 100B of modified example 2-2, biopotential can be easily detected by attaching a single electrode body 10D to the body.

[0063] (Variations 2-3) Figure 13 illustrates a biopotential sensor 100C according to a third modified example (modification 2-3) of the second embodiment of this disclosure. Figure 13 is a block diagram schematically showing an example of the overall configuration of the biopotential sensor 100C.

[0064] In the biopotential sensor 100C of this embodiment, for example, the signal processing unit 561 determines whether electrodes 10L and 10R are attached to the living body based on the biosignal obtained from the living body. Specifically, the signal processing unit 561, as a discrimination unit, determines whether electrode 10L is attached to the living body based on the change in the living body impedance between the first conductive portion 11L and the second conductive portion 12L of electrode 10L. Similarly, the signal processing unit 561, as a discrimination unit, determines whether electrode 10R is attached to the living body based on the change in the living body impedance between the first conductive portion 11R and the second conductive portion 12R of electrode 10R.

[0065] The signal processing unit 561 may, for example, determine whether or not electrodes 10L and 10R are attached to the living body based on the real part of the measured impedance of the living body, among the real and imaginary parts.

[0066] The biopotential sensor 100C may further include a current supply unit 58, such as a secondary battery 581, as shown in Figure 13. The current supply unit 58 supplies current between the first conductive portion 11L and the second conductive portion 12L, and between the first conductive portion 11R and the second conductive portion 12R. The current is, for example, a sine wave, square wave, or triangular wave having a frequency greater than 0 and less than or equal to 1000 Hz. Although Figure 13 shows an example in which the current supply unit 58 is provided inside the main body 30L, 30R, the current supply unit 58 may be provided outside the main body 30L, 30R.

[0067] According to the biopotential sensor 100C of modified example 2-3, it is possible to easily and accurately detect whether electrodes 10L and 10R are attached to the body, respectively.

[0068] To date, for example, Japanese Patent Publication No. 2018-515045 proposes a method for detecting whether wireless earphones are worn in a user's ears using sensors such as optical proximity sensors, pressure sensors, heat sensors, and humidity sensors. However, there is considerable individual variation in the shape of users' ears, and in some cases, it may be difficult to determine whether a device such as wireless earphones is being worn. When determining whether or not a device is being worn using an optical proximity sensor, for example, it may be incorrectly determined that the wireless earphones are being worn even if they are actually resting on a desk.

[0069] In this respect, in the biopotential sensor 100C of modified example 2-3, the signal processing unit 561, which acts as a discrimination unit, determines whether the electrodes 10L and 10R are attached to the body based on biosignals obtained from the body, such as bioimpedance. Therefore, the possibility of misjudging a state where the device is placed on a desk as a state where it is attached to the ear can be eliminated. Furthermore, the electrodes 10L and 10R each have a first conductive portion 11 including a first elastic portion E1 and a second conductive portion 12 including a second elastic portion E2. Therefore, a good state of contact between each of the electrodes 10L and 10R and the body can be maintained. To obtain bioimpedance, it is usually necessary to measure the impedance between two points, but with the electrodes 10L and 10R, high contact can be obtained even in a minute section within a single ear canal. Therefore, the biopotential sensor 100C can detect with high accuracy whether the electrodes 10L and 10R are attached to the body.

[0070] (Modification 2-4) In the biopotential sensor 100C of the above modified example 2-3, the presence or absence of electrodes 10L and 10R attached to a living body is determined by detecting bioimpedance, but the disclosure is not limited thereto. Figure 14 is a schematic block diagram showing an example of the overall configuration of a biopotential sensor 100D according to the fourth modified example (modified example 2-4) of the second embodiment of the disclosure.

[0071] In the modified biopotential sensor 100D of the above embodiment, in addition to the biopotential sensor 100, an oscillation circuit 59 that emits electrical vibrations is further included. In the biopotential sensor 100D, the signal processing unit 561 acts as a discrimination unit and determines whether the electrodes 10L and 10R are attached to the living body based on the change in the oscillation frequency of the electrical vibrations emitted by the oscillation circuit 59. That is, the signal processing unit 561 detects the change in the charge amount of each electrode 10L and 10R due to the frequency change of the oscillation circuit 59 and determines whether the electrodes 10L and 10R are in contact with the ear canal of the living body.

[0072] In the biopotential sensor 100D of modified example 2-4, it is possible to easily and accurately detect whether the electrodes 10L and 10R are attached to the living body, respectively.

[0073] <3. Other variations> The technology of this disclosure has been described above with reference to several embodiments and modifications. However, the technology of this disclosure is not limited to the embodiments described above, and various modifications are possible.

[0074] For example, in the electrode body 10 of the first embodiment, the first elastic portion E1 and the second elastic portion E2 are solid bodies that do not contain voids or air bubbles, but the disclosure is not limited thereto. For example, the first elastic resin of the conductive portion may be a foam containing air bubbles. Similarly, the second elastic resin of the insulating portion may be a solid body that does not contain voids or air bubbles, or it may be a foam containing air bubbles.

[0075] Furthermore, in the second embodiment and others, a wireless earphone-type biopotential sensor 100 was used as an example to describe the biopotential sensor, but the present disclosure is not limited thereto. The biopotential sensor of the present disclosure may be provided, for example, as part of a head-mounted display 200 shown in Figure 15. In the head-mounted display 200, the electrode body 10 can be provided, for example, on the inner surface of the pad portion 201 and the band portion 202.

[0076] Alternatively, the biopotential sensor of this disclosure may be provided as part of a headband 300, for example, as shown in Figure 16. In the headband 300, the electrode body 10 can be provided, for example, on the inner surface of the band portions 301, 302 that come into contact with the head.

[0077] Alternatively, the biopotential sensor of this disclosure may be provided as part of the headphones 400 shown in Figure 17, for example. In the headphones 400, the electrode body 10 can be provided, for example, on the inner surface of the band portion 401 that comes into contact with the head, or on the ear pads 402, etc.

[0078] Alternatively, the biopotential sensor of this disclosure may be provided as part of a cap 500, for example, as shown in Figure 18. In the cap 500, the electrode body 10 can be provided, for example, on the inner surface that comes into contact with the forehead.

[0079] Furthermore, not all configurations and operations described in each embodiment are necessarily essential to the configurations and operations of the present disclosure. For example, any component in each embodiment that is not described in an independent claim representing the highest-level concept of the present disclosure should be understood as an optional component.

[0080] Terms used herein and throughout the appended claims should be interpreted as “non-limiting.” For example, the terms “includes” or “contains” should be interpreted as “not limited to the manner in which it is included.” The term “has” should be interpreted as “not limited to the manner in which it has been described.”

[0081] The terminology used herein includes terms used solely for explanatory purposes and not intended to limit the configuration or operation. For example, terms such as "right," "left," "up," and "down" merely indicate direction on the referenced drawing. Similarly, terms such as "inside" and "outside" merely indicate directions toward and away from the center of the element of interest, respectively. The same applies to similar or similar terms.

[0082] Furthermore, the technology relating to this disclosure can also take the following configuration. The biopotential electrode body of this disclosure having the following configuration has high mechanical strength and is suitable for obtaining more biological information. Furthermore, the effects of the technology relating to this disclosure are not necessarily limited to those described herein, but may be any of the effects described in this disclosure. (1) Multiple conductive parts, each containing a contact surface that can come into contact with a living organism, One or more insulating portions that electrically insulate the plurality of conductive portions from each other It has, The conductive portion comprises a first elastic resin and a plurality of first particles embedded in the first elastic resin. The insulating portion includes a second elastic resin and a plurality of second particles embedded in the second elastic resin. Bioelectric potential electrodes. (2) The first particle is a conductor, and the second particle is an insulator. The bioelectric electrode described in (1) above. (3) The first elastic resin and the second elastic resin are insulators. The bioelectric electrode described in (2) above. (4) The first elastic resin and the second elastic resin are both substantially the same material. The bioelectric electrode described in (3) above. (5) The first particle includes carbon particles or metal particles. A bioelectric electrode described in any one of the above (1) to (4). (6) The metal particles consist of at least one of gold (Au), silver (Ag), and copper (Cu). The bioelectric electrode described in (5) above. (7) The first particle comprises a metal particle and a metal compound covering at least a portion of the surface of the metal particle. A bioelectric electrode described in any one of the above (1) to (6). (8) The aforementioned metal compound is a sulfide, selenide, or chloride of at least one metal selected from gold (Au), silver (Ag), and copper (Cu). The bioelectric electrode described in (7) above. (9) The first particle comprises a base particle and an organic conductive polymer covering at least a portion of the surface of the base particle. A bioelectric electrode described in any one of the above (1) to (8). (10) The organic conductive polymer includes at least one from the group consisting of PEDOT-PSS, polypyrrole, polyacetylene, polyphenylenevinylene, polythiophene, polythiol, and polyaniline, and their analogs. The bioelectric electrode described in (9) above. (11) The first elastic resin and the second elastic resin are at least one thermoplastic resin selected from the group consisting of polyvinyl chloride resin, polypropylene resin, polyethylene resin, polyurethane resin, polyacetal resin, polyamide resin, and polycarbonate resin, and copolymers thereof. A bioelectric electrode described in any one of the above (1) to (10). (12) The first elastic resin and the second elastic resin are natural rubber or diene rubber. A bioelectric electrode described in any one of the above (1) to (10). (13) The first elastic resin and the second elastic resin are thermosetting elastomers in which the base resin layer contains one selected from the group consisting of silicone resin and polyurethane resin. A bioelectric electrode described in any one of the above (1) to (10). (14) The second particle is made of titanium oxide. A bioelectric electrode described in any one of the above (1) to (13). (15) The plurality of conductive portions and the one or more insulating portions form a substantially cylindrical cylindrical structure as a whole. The conductive portion and the insulating portion are arranged alternately in the circumferential direction of the cylindrical structure. A bioelectric electrode described in any one of the above (1) to (14). (16) The plurality of conductive portions and the one or more insulating portions form a substantially cylindrical cylindrical structure as a whole. The plurality of conductive portions are separated in the axial direction of the cylindrical structure by the one or more insulating portions. A bioelectric electrode described in any one of the above (1) to (14). (17) A biopotential sensor equipped with a biopotential electrode, The biopotential electrode body is Multiple conductive parts, each containing a contact surface that can come into contact with a living organism, One or more insulating portions that electrically insulate the plurality of conductive portions from each other It has, The conductive portion comprises a first elastic resin and a plurality of first particles embedded in the first elastic resin. The insulating portion includes a second elastic resin and a plurality of second particles embedded in the second elastic resin. Bioelectric potential sensor. (18) The plurality of conductive portions include a first conductive portion and a second conductive portion. The first conductive portion is a measuring terminal for measuring the potential of the living organism. The second conductive portion is a ground terminal. The bioelectric electrode described in (17) above. (19) It also features a differential amplifier circuit, The plurality of conductive portions include a first conductive portion and a second conductive portion. The first conductive portion is a measuring terminal for measuring the potential of the living organism. The second conductive portion is a reference terminal for measuring the reference potential. The differential amplifier circuit detects the difference between the potential of the living organism and the reference potential. The bioelectric electrode described in (17) or (18) above. (20) The system further includes a discrimination unit that determines whether the biopotential electrode is attached to the living organism based on the biosignal obtained from the living organism. The bioelectric potential sensor described in (17) above. (twenty one) The plurality of conductive portions include a first conductive portion and a second conductive portion. The discrimination unit determines whether the biopotential electrode body is attached to the living body based on the change in the impedance of the living body between the first conductive portion and the second conductive portion. The bioelectric potential sensor described in (20) above. (twenty two) The discrimination unit determines, based on the actual value of the measured impedance of the living organism, whether the biopotential electrode body is attached to the living organism. The bioelectric potential sensor described in (21) above. (twenty three) The present invention further comprises a current supply unit that supplies a current having a frequency greater than 0 and less than or equal to 1000 Hz between the first conductive portion and the second conductive portion. The biopotential sensor described in (21) or (22) above. (twenty four) An oscillator circuit that generates electrical vibrations, A discrimination unit that determines whether the biopotential electrode body is attached to the living body based on the change in the oscillation frequency of the electrical vibration. Furthermore, it has The bioelectric potential sensor described in (17) above. [Explanation of Symbols]

[0083] 1...Electrode unit, 10(10L,10R)...Electrode body, 11(11L,11R)...First conductive part, 11SL,11SR...First surface, 12SL,12SR...Second surface, 13L,13R...Support, 14...First elastic resin, 15...First particle, 16...Second elastic resin, 17...Second particle, C1L,C1R...First core part, E1L,E1R...First elastic part, C2L,C2R...Second core part, E2L,E2R...Second elastic part, 12(12L,12R)...Second conductive part, Z1L,Z1R...First insulating part, Z2L,Z2R...Second insulating part, 10HL,10HR...Through hole, K1L~K4L,K1R~K4R...Interface, 100...Biopotential sensor.

Claims

1. A plurality of conductive portions each including a contact surface capable of contacting a living body; one or more insulating portions that electrically insulate the plurality of conductive portions from one another; having the conductive portion includes a first elastic resin and a plurality of first particles embedded in the first elastic resin, The insulator portion includes a second elastic resin and a plurality of second particles embedded in the second elastic resin. Biopotential electrode body.

2. The first particles are conductive and the second particles are insulators.

2. The biopotential electrode assembly of claim 1.

3. The first elastic resin and the second elastic resin are insulators. The biopotential electrode according to claim 2.

4. The first elastic resin and the second elastic resin are both substantially the same material. The biopotential electrode according to claim 3.

5. The first particles include carbon particles or metal particles.

2. The biopotential electrode assembly of claim 1.

6. The metal particles are made of at least one of gold (Au), silver (Ag) and copper (Cu). The biopotential electrode according to claim 5.

7. The first particles include metal particles and a metal compound that covers at least a portion of the surface of the metal particles.

2. The biopotential electrode assembly of claim 1.

8. The metal compound is a sulfide, selenide, or chloride of at least one metal selected from the group consisting of gold (Au), silver (Ag), and copper (Cu). The biopotential electrode assembly of claim 7.

9. The first particle includes a base particle and an organic conductive polymer covering at least a portion of the surface of the base particle.

2. The biopotential electrode assembly of claim 1.

10. The organic conductive polymer includes at least one member selected from the group consisting of PEDOT-PSS, polypyrrole, polyacetylene, polyphenylenevinylene, polythiophene, polythiol, and polyaniline, and their analogues.

10. The biopotential electrode assembly of claim 9.

11. The first elastic resin and the second elastic resin are at least one thermoplastic resin selected from the group consisting of polyvinyl chloride resin, polypropylene resin, polyethylene resin, polyurethane resin, polyacetal resin, polyamide resin, polycarbonate resin, and copolymers thereof.

2. The biopotential electrode assembly of claim 1.

12. The first elastic resin and the second elastic resin are natural rubber or diene rubber.

2. The biopotential electrode assembly of claim 1.

13. The first elastic resin and the second elastic resin are thermosetting elastomers including one selected from the group consisting of silicone resins and polyurethane resins.

2. The biopotential electrode assembly of claim 1.

14. The second particles are made of titanium oxide.

2. The biopotential electrode assembly of claim 1.

15. the plurality of conductive portions and the one or more insulator portions collectively form a generally cylindrical cylindrical structure; The biopotential electrode of claim 1 , wherein the conductive portions and the insulator portions are interleaved in a circumferential direction of the cylindrical structure.

16. the plurality of conductive portions and the one or more insulator portions collectively form a generally cylindrical cylindrical structure; The conductive portions are separated axially of the cylindrical structure by the one or more insulating portions.

2. The biopotential electrode assembly of claim 1.

17. A biopotential sensor including a biopotential electrode body, The biopotential electrode body is A plurality of conductive portions each including a contact surface capable of contacting a living body; one or more insulating portions that electrically insulate the plurality of conductive portions from one another; having the conductive portion includes a first elastic resin and a plurality of first particles embedded in the first elastic resin, The insulator portion includes a second elastic resin and a plurality of second particles embedded in the second elastic resin. Biopotential sensors.

18. the plurality of conductor portions include a first conductor portion and a second conductor portion; the first conductor portion is a measurement terminal for measuring an electric potential of the living body, The second conductive portion is a ground terminal.

20. The biopotential sensor of claim 17.

19. A differential amplifier circuit is further provided, the plurality of conductor portions include a first conductor portion and a second conductor portion; the first conductor portion is a measurement terminal for measuring an electric potential of the living body, the second conductive portion is a reference terminal for measuring a reference potential; The differential amplifier circuit detects a difference between the potential of the living body and the reference potential.

20. The biopotential sensor of claim 17.

20. The device further includes a determination unit that determines whether the biopotential electrode unit is attached to the living body based on a biosignal obtained from the living body.

20. The biopotential sensor of claim 17.

21. the plurality of conductor portions include a first conductor portion and a second conductor portion; The determination unit determines that the biopotential electrode unit is attached to the living body based on a change in impedance of the living body between the first conductive portion and the second conductive portion.

21. The biopotential sensor of claim 20.

22. The determination unit determines whether the biopotential electrode unit is attached to the living body based on a real part of a measured impedance of the living body.

22. The biopotential sensor of claim 21.

23. The present invention further includes a current supply unit that supplies a current having a frequency greater than 0 and less than or equal to 1000 Hz between the first conductive portion and the second conductive portion.

22. The biopotential sensor of claim 21.

24. An oscillator circuit that generates an electrical oscillation; a discrimination unit that discriminates whether the biopotential electrode unit is attached to the living body based on a change in the oscillation frequency of the electrical vibration; Further having 20. The biopotential sensor of claim 17.

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