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]

[0001] The present disclosure relates to a biopotential sensor that is brought into contact with a living body to detect a biosignal, and a biopotential electrode body used therefor. [Background technology]

[0002] Earphone-type biopotential sensors that detect biosignals such as brain waves, heartbeats, or pulse rates have been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-24758 Summary of the Invention [Problem to be solved by the invention]

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

[0005] It is desirable for a biopotential sensor to be highly durable and to be able to obtain as much bioinformation as possible.

[0006] Therefore, there is a demand for a biopotential sensor that has high mechanical strength and is suitable for obtaining a greater amount of biological information, as well as a biopotential electrode used therein. [Means for solving the problem]

[0007] A biopotential electrode body according to an embodiment of the present disclosure includes a plurality of conductive body portions each including a contact surface that can come into contact with a living body; bodyand one or more insulating portions that electrically insulate the conductive portions from one another. The conductive portion includes 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. The plurality of conductive portions and the one or more insulating portions collectively form a substantially cylindrical structure, and the volume ratio of one of the plurality of conductive portions is higher than the volume ratios of the other conductive portions.

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

[0009] In the biopotential electrode assembly and biopotential sensor according to an embodiment of the present disclosure, The overall structure is substantially cylindrical. Since the device includes multiple conductive portions insulated from one another, it is possible to detect the potential of multiple locations on the living body. Furthermore, since the conductive portion includes multiple first particles and the insulator portion includes multiple second particles, peeling between the conductive portion and the insulator portion is unlikely to occur. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically illustrating the overall configuration of an electrode body unit having a pair of electrode bodies according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective view schematically illustrating the appearance of the electrode body shown in FIG. [Figure 3] 1. FIG. 4 is a cross-sectional view schematically showing another cross section of the electrode body shown in FIG. [Figure 4] FIG. 2 is a cross-sectional view illustrating the details of the electrode body shown in FIG. [Figure 5] 2 is a cross-sectional view showing details of a first particle included in the electrode body shown in FIG. 1. FIG. [Figure 6] 1. FIG. 4 is a cross-sectional view showing details of another first particle included in the electrode body shown in FIG. [Figure 7] FIG. 2 is a cross-sectional view illustrating a configuration example of an electrode body according to a first modified example of the first embodiment of the present disclosure. [Figure 8] FIG. 10 is a cross-sectional view illustrating a configuration example of an electrode body according to a second modified example of the first embodiment of the present disclosure. [Figure 9A]FIG. 10 is a perspective view schematically illustrating an example of the overall configuration of a biopotential sensor according to a second embodiment of the present disclosure. [Figure 9B] FIG. 9B is an exploded perspective view of the biopotential sensor shown in FIG. 9A. [Figure 10] FIG. 9B is a block diagram schematically illustrating an example of the overall configuration of the biopotential sensor shown in FIG. 9A. [Figure 11] FIG. 10 is a cross-sectional view illustrating a configuration example of an electrode body according to a first modified example of the second embodiment of the present disclosure. [Figure 12] FIG. 10 is a cross-sectional view illustrating a configuration example of an electrode body according to a second modified example of the second embodiment of the present disclosure. [Figure 13] FIG. 10 is a block diagram schematically illustrating an example of the overall configuration of a biopotential sensor according to a third modified example of the second embodiment of the present disclosure. [Figure 14] FIG. 10 is a block diagram schematically illustrating an example of the overall configuration of a biopotential sensor according to a fourth modified example of the second embodiment of the present disclosure. [Figure 15] FIG. 2 is a schematic diagram illustrating an example in which the electrode body shown in FIG. 1 is used in a head-mounted display. [Figure 16] FIG. 2 is a schematic diagram illustrating an example in which the electrode body shown in FIG. 1 is used in a headband. [Figure 17] FIG. 2 is a schematic diagram illustrating an example in which the electrode body shown in FIG. 1 is used in headphones. [Figure 18] FIG. 2 is a schematic diagram illustrating an example in which the electrode body shown in FIG. 1 is used as a cap. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiment described below is a specific example of the present disclosure, and the technology according to the present disclosure is not limited to the following aspects. Furthermore, the arrangement, dimensions, dimensional ratios, etc. of each component of the present disclosure are not limited to the aspects shown in the drawings.

[0012] The explanation will be given in the following order. 0. Background 1. First embodiment (biopotential electrode assembly) 1.1.Configuration Example 1.2. Manufacturing method 1.3.Effects 1.4. Variations 2. Second embodiment (biopotential sensor) 2.1.Configuration Example 2.2.Effects 2.3. Variations 3. Other Modifications

[0013] <0. Background> Until now, wet electrodes have often been used to measure bioelectrical potentials such as electroencephalograms (EEG) and bioimpedance such as electrodermal activity (EDA). Wet electrodes are electrodes that reduce contact impedance with the body using, for example, measurement gel or saline solution. However, for consumer applications, wet electrodes have often been avoided due to concerns about contamination caused by gel adhesion, deterioration of the gel over time, and the hassle of measurement preparation. For this reason, measurement devices using dry electrodes have recently begun to be proposed (see, for example, "Dry EEG Electrodes," Sensors, 14, 12847 (2014)).

[0014] Various proposals have been made regarding materials for such dry electrodes. For example, Japanese Patent Application No. 2010-247047 proposes a nitrile rubber composition in which conductive particles such as carbon are mixed into an elastomer such as rubber. Because this nitrile rubber composition is highly flexible, its use as a material for dry electrodes is expected to improve comfort when worn.

[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 these cases, electrodes are placed in contact with limited areas of the human skin surface, such as the outer ear or the area surrounding the outer ear.

[0016] For example, in the above-mentioned Patent Document 1, a conductive resin is used for electrical contact with the inner surface of the ear canal. However, in an earphone-type biopotential sensor like that in Patent Document 1, the electrodes are in contact with the limited skin surface, which is the inner surface of the ear canal. As a result, the biological information obtained is limited to one point.

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

[0018] <1. First embodiment> [1.1. Configuration example] (Electrode unit 1) First, an electrode unit 1 as a biopotential electrode according to a first embodiment of the present 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 electrode assemblies 10L and 10R. Figure 3 is a second cross-sectional view showing a cross section of the electrode assemblies 10L and 10R that is perpendicular to the cross section shown in Figure 1.

[0019] As shown in Fig. 1, the electrode body unit 1 has a pair of electrode bodies 10L, 10R. As shown in Figs. 1 to 3, the pair of electrode bodies 10L, 10R have substantially the same structure. Therefore, of the pair of electrode bodies 10L, 10R, only the electrode body 10L will be described below. In this specification, when there is no need to distinguish between the pair of electrode bodies 10L, 10R, they may be simply referred to as electrode body 10.

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

[0021] (1st conductor part 11L) The first conductor 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 layered in the radial direction of the cylindrical structure. The first core portion C1L is located inside the cylindrical structure. The first elastic portion E1L is located outside the cylindrical structure. The first elastic portion E1L includes a first surface 11SL on the side opposite the through-hole 10HL. The first surface 11SL is a contact surface that can come into contact with the surface of a living body, for example, the surface of human skin. The first core portion C1L is primarily composed of a highly conductive metal material such as Au (gold), Ag (silver), or Cu (copper). The first core portion C1L is a portion that comes into contact with, for example, a first electrode 131 (see FIG. 4 ) of the support member 13L inserted into the through-hole 10HL.

[0022] (Second conductor part 12L) The second conductor portion 12L has substantially the same configuration as the first conductor portion 11L. That is, the second conductor 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 layered in the radial direction of the cylindrical structure. The second core portion C2L is located on the inner side of the cylindrical structure. The second elastic portion E2L is located on the outer side of the cylindrical structure. The second elastic portion E2L includes a second surface 12SL on the side opposite the through-hole 10HL. The second surface 12SL is a contact surface that can come into contact with the surface of a living body, for example, the surface of human skin. The second core portion C2L mainly contains a highly conductive metal material such as Au (gold), Ag (silver), or Cu (copper). The second core portion C2L is a portion that comes into contact with, for example, the second electrode 132 (see FIG. 4 ) of the support member 13L inserted into the through-hole 10HL.

[0023] (First elastic portion E1L and second elastic portion E2L) FIG. 4 is a cross-sectional view showing details of the electrode body 10L shown in FIG. 1. As shown in FIG. 4, the first elastic portion E1L and the second elastic portion E2L each include 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. The first particles 15, which are conductive, are dispersed and contained in the first elastic resin 14, thereby making the first elastic portion E1L and the second elastic portion E2L conductive. The first elastic portion E1L and the second elastic portion E2L each include, for example, 30 wt % of the first particles 15.

[0024] The average primary particle diameter of the first particles 15 is preferably within a range of, for example, 10 to 100 nm. This is because the first particles 15 are more likely to be dispersed more uniformly in the first elastic resin 14. When the first particles 15 are conductive particles, more uniform dispersion of the first particles 15 in the first elastic resin 14 is preferable because this improves the conductivity of the first elastic portion E1L and the conductivity of the second elastic portion E2L.

[0025] The average secondary particle diameter of the first particles 15 is preferably within a range of 30 to 500 nm. 1st particle 15 By having a secondary particle size such that is within the above range, 1st particle 15 but First Elastic Resin 14 This makes it easier for the particles to disperse in the air, making it possible to further improve measurement accuracy.

[0026] where: 1st particle 15 The average primary particle size and the average secondary particle size can be measured by direct observation using a transmission electron microscope (TEM) or by particle size measurement using a dynamic light scattering method.

[0027] FIG. 5 is a schematic diagram illustrating an example of the cross-sectional structure of a first particle 15. As shown in FIG. 5, the first particle 15 has a base particle 151 and a surface-treated portion 152. The base particle 151 is, for example, a conductor or insulator having a surface 151S. Note that FIG. 5 schematically illustrates a spherical base particle 151, but in the present disclosure, the shape of the base particle is not limited to a sphere and may be an ellipsoid or have an uneven surface. The surface-treated portion 152 is, for example, a conductor, and covers or replaces at least a portion of the surface 151S of the base particle 151. Furthermore, the first particle 15 does not need to have the surface-treated portion 152 as long as the base particle 151 is conductive. Furthermore, as shown in FIG. 5, the surface-treated portion 152 is preferably present over the entire surface 151S of the base particle 151. However, the first particle of the present disclosure also includes first particle 15A in which surface treatment portion 152 is selectively present only on a portion of surface 151S of base particle 151, as shown in FIG.

[0028] The base particle 151 may be, for example, a carbon particle or a metal particle. This is because these carbon particles and metal particles are themselves conductive and therefore easily ensure the conductivity of the first elastic portion E1L and the second elastic portion E2L. The metal particle serving as the base particle 151 is, for example, made of at least one metal selected from gold (Au), silver (Ag), and copper (Cu). When the base particle 151 is a metal particle, the surface treatment portion 152 may be a metal compound that covers at least a portion of the surface 151S of the base particle 151. The metal compound serving as the surface treatment portion 152 is, for example, a sulfide, selenide, or chloride of at least one metal selected from gold (Au), silver (Ag), and copper (Cu).

[0029] The carbon particles serving as the substrate 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 granulated flakes or fibers of carbon black (graphite), carbon nanotubes, and graphene.

[0030] The base particle 151 may be, for example, a polymer particle. The polymer particle is a particle made of various resin compositions, such as polyphenylene sulfide (PPS) resin, polyethylene terephthalate (PolyEthyleneTere p Polyvinyl phthalate (PET) resin, Polyethersulfone (PolyEtherSulfone: PES) resin, Polyamide-imide (PolyAmide-Imide: PAI) resin, acrylic resin, Polyvinylidene difluoride (Polyvinylidene difluoride: PVDF) resin, epoxy resin, polylactic acid resin, Examples of the resin include particles of iron resin, urethane resin, etc.

[0031] For example, when the base particle 151 of the first particle 15 is an insulating particle, the surface-treated portion 152 may include, for example, an organic conductive polymer. The organic conductive polymer used as the surface-treated portion 152 includes at least one selected from the group consisting of PEDOT-PSS, polypyrrole, polyacetylene, polyphenylene vinylene, polythiophene, polythiol, polyaniline, and their analogs. The surface-treated portion 152 may include any of the above organic conductive polymers, either singly or in combination. When using an organic conductive polymer as the surface-treated portion 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 adhesion between the base particle 151 and the surface-treated portion 152. The organic conductive polymer used as the surface-treated portion 152 may 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 insulator portion Z1L and second insulator portion Z2L) As shown in FIG. 4, the first insulator portion Z1L and the second insulator portion Z2L each include 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. The second particles 17 may be, for example, titanium oxide such as TiO2. The first insulator portion Z1L and the second insulator portion Z2L each include, for example, 20 wt% of the second particles 17.

[0033] The first elastic resin 14 and the second elastic resin 16 are resins whose main component is 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 a resin component whose main component is a predetermined resin material, rubber, or elastomer. Here, the term "solidified product" simply refers to a resin component that has solidified, and the term "cured product" refers to a resin component that has been cured by adding various curing agents to the resin component. Furthermore, the term "main component" refers to a component that is contained in an amount of 50 parts by mass or more out of 100 parts by mass of the total resin component, and the term "resin component" does not include non-resin components such as crosslinking agents.

[0034] The Shore hardness (Shore A hardness) of each of the first elastic resin 14 and the second elastic resin 16 is preferably 70 HS or less. 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 mixing the first particles 15 into the first elastic resin 14, can be 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 mixing the second particles 17 into the second elastic resin 16, can be 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, they can easily follow the movement of a living body, even when the body moves, thereby further improving adhesion to the living body. Furthermore, comfort is ensured when the electrode body 10L is attached to a 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] In the electrode body 10L, at least the first conductive portion 11L including the first surface 11SL that comes into contact with the living body and the second conductive portion 12L including the second surface 12SL have the above-described first elastic resin 14. This makes it possible to sufficiently maintain 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 rubber that can be used for the first elastic resin 14 and the second elastic resin 16 include natural rubber and synthetic rubber. Examples of synthetic rubber include diene rubbers such as styrene butadiene rubber and isoprene rubber.

[0038] Furthermore, examples of the elastomer used for the first elastic resin 14 and the second elastic resin 16 include thermosetting elastomers including one selected from the group consisting of silicone resins and polyurethane resins.

[0039] The above-mentioned resin materials, rubbers, and elastomers 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 FIG. 4, the through hole 10HL is provided so that the support 13L can be inserted therein. 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 columnar shape. The support 13L includes a first electrode 131, a second electrode 132, and an insulating portion 133. The first electrode 131 is a portion that contacts the first core portion C1L. The second electrode 132 is a 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 the electrode assembly 10R is substantially the same as the configuration of the electrode assembly 10L described above. Specifically, for example, the configuration of the electrode body 10R can be explained by replacing the first conductor portion 11L, the second conductor portion 12L, the first insulator portion Z1L, the second insulator portion Z2L, the through hole 10HL, the interface K1L, the interface K2L, the interface K3L, the interface K4L, the first core portion C1L, the first elastic portion E1L, the first surface 11SL, the second core portion C2L, the second elastic portion E2L, and the second surface 12SL of the electrode body 10L with the first conductor portion 11R, the second conductor portion 12R, the first insulator portion Z1R, the second insulator portion Z2R, the through hole 10HR, the interface K1R, the interface K2R, the interface K3R, the interface K4R, the first core portion C1R, the first elastic portion E1R, the first surface 11SR, the second core portion C2R, the second elastic portion E2R, and the second surface 12SR, respectively, as shown in Figure 4. The through-hole 10HR is provided with a support 13R that can be inserted therein, as shown in Fig. 4. The configuration of the support 13R is substantially the same as the configuration of the support 13L.

[0042] In the following description, the first conductor portion 11L and the first conductor portion 11R may be collectively referred to as the first conductor portion 11. Similarly, the second conductor portion 12L and the second conductor portion 12R may be collectively referred to as the second conductor portion 12. The first insulator portion Z1L and the first insulator portion Z1R may be collectively referred to as the first insulator portion Z1. The second insulator portion Z2L and the second insulator portion Z2R may be collectively referred to as the second insulator portion Z2. The through hole 10HL and the through hole 10HR may be collectively referred to as the through hole 10H. The interface K1L, the interface K2L, the interface K3L, the interface K4L, the interface K1R, the interface K2R, the interface K3R, and the interface K4R may be collectively referred to as the interface K. Furthermore, the first elastic portion E1L and the first elastic portion E1R may be collectively referred to as the first elastic portion E1. The first surface 11SL and the first surface 11SR may be collectively referred to as the first surface 11S. The second elastic portion E2L and the second elastic portion E2R may be collectively referred to as the second elastic portion E2. 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 of manufacturing electrode body 10) Next, a brief description will be given of a method for manufacturing the electrode body 10 of this embodiment. The electrode body 10 can be manufactured using so-called injection molding technology. The manufacturing process includes, for example, first to third steps. The first step is a step of manufacturing the first particles 15 and the second particles 17. The second step is a step of kneading the manufactured first particles 15 and the second particles 17 with the first elastic resin 14 and the second elastic resin 16, respectively, to manufacture the first kneaded resin composition and the second kneaded resin composition, respectively. The third step includes a third step of simultaneously injection-molding the first kneaded resin composition and the second kneaded resin composition to manufacture the electrode body 10 in which the first conductor portions 11 and the second conductor portions 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 may be produced by a known method, such as by passing a compound for forming the surface-treated part 152 through a container filled with base particles 151, or by adding the base particles 151 to a solution containing a compound for forming the surface-treated part 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 may be carried out by a known method. Note that when the first particles 15 are kneaded into the first elastic resin 14, the average particle size of the secondary aggregates (agglomerates) of the first particles 15 is, for example, about 1 μm to 200 μm.

[0045] Furthermore, in the third step described above, it is possible to manufacture the electrode body 10 in any desired size and shape by using various known injection molding techniques, such as two-color molding.

[0046] [1.3. Action and Effects] The electrode assembly 10 of this embodiment includes a first conductive portion 11, a second conductive portion 12, 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, as contact surfaces that can come into contact with a living body. 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 the living body can be detected at the contact point between the first surface 11S of the first conductive portion 11 and the living body, and at the contact point between the second surface 12S of the second conductive portion 12 and the living body. In other words, the electrode assembly 10 can be used to detect the potential at multiple locations on the living body.

[0047] Furthermore, in the electrode body 10 of this embodiment, the first conductive portion 11 includes the first elastic portion E1, and the second conductive portion 12 includes the second elastic portion E2, which makes it possible to maintain good contact between the first surface 11S and the living body, and between the second surface 12S and the living body.

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

[0049] Furthermore, in the electrode body 10, the first insulating portion Z1 and the second insulating portion Z2 contain a second elastic resin 16 and a plurality of second particles 17. Therefore, compared to when the first insulating portion Z1 and the second insulating portion Z2 do not contain the second particles 17, peeling is less likely to occur at the interfaces 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 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, thereby mitigating stress concentration at the interfaces K. This improves the mechanical strength of the electrode body 10 and its long-term reliability.

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

[0051] In addition, in the electrode body 10, the first conductive body Part 11, first insulating part Z1 and second conductive part body The portions 12 and the second insulator portions 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 respective measurement sites of the living body. For example, when the electrode unit 10 is attached to the external ear canal of the human body to detect the electroencephalogram (EEG) of the human body, the first surface 11S of the first conductive portion 11 may be brought into contact with the portion of the inner surface of the external ear canal near the top of the head 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 portion of the inner surface of the external ear canal near the neck where the EEG intensity is relatively weak. In this case, it is possible to measure the potential difference between the portion near the top of the head and the portion near the neck.

[0052] [1.4. Modifications] (Variation 1-1) FIG. 7 is a cross-sectional view illustrating a configuration example of an electrode body 10A according to a first modified example (modified example 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 containing no cavities or bubbles. In contrast, the electrode body 10A of modified example 1-1 includes cavities V1 and V2 in the first elastic portion E1 and the second elastic portion E2, respectively. According to the electrode body 10A of modified example 1-1, the inclusion of cavities V1 and V2 provides the first conductor portion 11 and the second conductor portion 12 with even higher elasticity. This allows for even better maintenance of intimate contact between the first surface 11S and the living body, and between the second surface 12S and the living body. Note that cavities may also be provided in the first insulator portion Z1 and the second insulator portion Z2.

[0053] (Variation 1-2) FIG. 8 is a cross-sectional view showing a configuration example of an electrode body 10B according to a second modified example (modified example 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 each extend radially from the center of the cylindrical structure. In contrast, the electrode body 10B as modified example 1-2 has a plurality of conductive portions. bodyThe first and second conductor portions 11, 12 are separated in the axial direction of the cylindrical structure by the insulator portion. That is, in the electrode body 10B of Variation 1-2, the first conductor portion 11, the insulator portion Z, and the second conductor portion 12 are arranged in this order in the Z-axis direction indicated by the arrow. Here, the insulator portion Z has the same configuration as at least one of the first insulator portion Z1 and the second insulator portion Z2, for example. In the electrode body 10B of Variation 1-2, the first conductor portion 11 and the second conductor portion 12 are each arranged without interruption around the entire circumferential direction of the cylindrical structure. Therefore, when attaching the electrode body 10B to the external ear canal of a human body, for example, it is not necessary to align the circumferential position of the cylindrical structure with the position of the inner surface of the external ear canal. Furthermore, as will be described later, this electrode body is suitable for using the first conductor portion 11 as a terminal for detecting biopotentials and the second conductor portion 12 as a reference terminal or ground terminal.

[0054] 2. Second embodiment [2.1. Configuration example] (Biopotential sensor 100) Next, a biopotential sensor 100 according to a second embodiment of the present disclosure will be described with reference to Figures 9A to 10. Figure 9A is a perspective view schematically illustrating 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 illustrating 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 FIG. 9A, the biopotential sensor 100 includes electrode bodies 10L and 10R and main bodies 30L and 30R. FIG. 9B shows the electrode bodies 10L and 10R detached from the main bodies 30L and 30R. As shown in FIG. 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 supports 13L and 13R inserted into through-holes 10HL and 10HR, respectively.

[0056] As shown in FIG. 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. The terminals T1 to T3 are included in the 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 bodies 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 a 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 communicably connected to an external device 57, such as a personal computer (PC), for example, wirelessly or via a wired connection. The external device 57 includes a computing unit 571 such as a central processing unit (CPU).

[0057] The terminals T1 to T3 are each adapted to contact a different location on the skin surface SS of a living body. The biopotential sensor 100 can be used to measure a human brain wave by, for example, attaching the electrode assembly 10L to the left external ear canal and the electrode assembly 10R to the right external ear canal. In this case, in the biopotential sensor 100, the first conductor portion 11L of the electrode assembly 10L and the first conductor portion 11R of the electrode assembly 10R are used as terminal T1. The first surface 11SL of the first conductor portion 11L and the first surface 11SR of the first conductor portion 11R are preferably in contact with the inner surfaces of the left and right external ear canals, near the top of the head, where EEG intensity is relatively strong. The second conductor portion 12L of the electrode assembly 10L is used as terminal T2, for example. In this case, the second surface 12SL of the second conductor portion 12L is preferably in contact with the inner surfaces of the external ear canals, near the neck, where EEG intensity is relatively weak. Terminal T2 is, for example, a reference terminal that detects a potential that serves as a reference for measuring the difference from the potential detected at terminal T1. Furthermore, second conductive portion 12R of electrode assembly 10R is used, for example, as terminal T3. In this case, second surface 12SR of second conductive portion 12R may be in contact with the inner surface of the external auditory canal, near the neck, where the EEG intensity is relatively weak. Terminal T3 is, for example, a ground terminal.

[0058] [2.2. Action and Effects] As described above, the biopotential sensor 100 of this embodiment includes the electrodes 10L and 10R described in the first embodiment, and can therefore be used to detect potentials at multiple locations on a living body. For example, by contacting the first surface 11S of the first conductor portion 11 with the inner surface of the external auditory canal near the top of the head, where EEG intensity is relatively strong, and contacting the second surface 12S of the second conductor portion 12 with the inner surface of the external auditory canal near the neck, where EEG intensity is relatively weak, the potential difference between the potential at the top of the head and the potential at the neck canal can be easily measured. This allows for more accurate detection of human brain waves. Furthermore, the electrode portion 10 has excellent mechanical strength, improving the long-term reliability of the biopotential sensor 100.

[0059] [2.3. Modifications] (Variation 2-1) FIG. 11 is a schematic diagram illustrating an example cross-sectional configuration of an 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. The biopotential sensor 100 of the second embodiment uses an electrode assembly 10L and an electrode assembly 10R having substantially the same configuration. In contrast, the electrode assembly unit 1C of modification 2-1 includes an electrode assembly 10CL and an electrode assembly 10CR having mutually different configurations. Specifically, as shown in FIG. 11, for example, in an electrode assembly 10CR to be fitted in the right external auditory canal, a first conductor portion 11R is provided so as to occupy the entire circumferential direction of the cylindrical structure. On the other hand, in an electrode assembly 10CL to be fitted in the left external auditory canal, a first conductor portion 11L, a first insulator portion Z1L, a second conductor portion 12L, and a second insulator portion Z2L are alternately arranged in the circumferential direction of the cylindrical structure. In the 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 body 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 body 13R is provided with a first electrode 131 corresponding to the first conductive portion 11R.

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

[0061] (Variation 2-2) FIG. 12 is a schematic diagram illustrating an example cross-sectional configuration of an electrode assembly 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, an electrode assembly unit 1 including a pair of electrode assemblies 10L and 10R is used. In contrast, in the biopotential sensor 100B of modification 2-2, one electrode assembly 10D is assigned to terminals T1 to T3. When the biopotential sensor 100B detects, for example, human brain waves, the electrode assembly 10D is attached to the right or left external auditory canal. As shown in FIG. 12, the electrode assembly 10D has three conductor portions, namely, first to third conductor portions 11 to 13. The electrode assembly 10D further has first to third insulator portions Z1 to Z3 that are provided to electrically isolate the first to third conductor portions 11 to 13 from one another. 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 modification 2-2, a biopotential can be easily detected by attaching one electrode body 10D to a living body.

[0063] (Variation 2-3) Fig. 13 illustrates a biopotential sensor 100C according to a third modified example (modification example 2-3) of the second embodiment of the present disclosure. Fig. 13 is a block diagram schematically illustrating 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 is configured to determine whether the electrode bodies 10L and 10R are attached to a living organism based on a biosignal obtained from the living organism. That is, the signal processing unit 561, as a determination unit, is configured to determine whether the electrode body 10L is attached to a living organism based on a change in the impedance of the living organism between the first conductive portion 11L and the second conductive portion 12L of the electrode body 10L. Similarly, the signal processing unit 561, as a determination unit, is configured to determine whether the electrode body 10R is attached to a living organism based on a change in the impedance of the living organism between the first conductive portion 11R and the second conductive portion 12R of the electrode body 10R.

[0065] The signal processing unit 561 may determine whether the electrode assemblies 10L, 10R are attached to the living body based on, for example, the real part of the real and imaginary parts of the measured value of the impedance of the living body.

[0066] As shown in FIG. 13, the biopotential sensor 100C may further include a current supply unit 58 including, for example, a secondary battery 581. 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 may be, for example, a sine wave, square wave, or triangular wave having a frequency greater than 0 and equal to or less than 1000 Hz. Although FIG. 13 shows an example in which the current supply unit 58 is provided inside the main bodies 30L and 30R, the current supply unit 58 may also be provided outside the main bodies 30L and 30R.

[0067] According to the biopotential sensor 100C of the modification 2-3, it is possible to easily and accurately detect whether the electrode assemblies 10L, 10R are attached to a living body.

[0068] For example, JP 2018-515045 A has proposed 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 are significant individual differences in the shape of users' ears, and it can be difficult for some users to determine whether a device such as wireless earphones is worn. When determining whether a device is worn using an optical proximity sensor, there is a possibility that the wireless earphones may be mistakenly determined to be worn in the ears even when they are actually placed on a desk.

[0069] In contrast, in the biopotential sensor 100C of Modification 2-3, the signal processing unit 561, which serves as a discrimination unit, determines whether the electrode bodies 10L and 10R are attached to a living body based on biosignals obtained from the living body, such as bioimpedance. This eliminates the possibility of erroneously determining that the electrode bodies 10L and 10R are attached to the ear, even when the electrode bodies are placed on a desk. Furthermore, the electrode bodies 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. This ensures good contact between the electrode bodies 10L and 10R and the living body. While bioimpedance is typically measured by measuring impedance between two points, the electrode bodies 10L and 10R provide high contact even over a very small area within a single ear canal. Therefore, the biopotential sensor 100C can accurately detect whether the electrode bodies 10L and 10R are attached to the living body.

[0070] (Variation 2-4) In the biopotential sensor 100C of the above-described modification 2-3, the attachment of the electrode assemblies 10L, 10R to a living body is determined by detecting the bioimpedance, but the present disclosure is not limited to this. Fig. 14 is a block diagram schematically showing an example of the overall configuration of a biopotential sensor 100D according to a fourth modification (modification 2-4) of the second embodiment of the present disclosure.

[0071] A biopotential sensor 100D of Modification 2-4 further includes an oscillator circuit 59 that oscillates electrical vibrations in addition to the components of the biopotential sensor 100 of the above embodiment. In the biopotential sensor 100D, a signal processing unit 561 serves as a discrimination unit that determines whether the electrode assemblies 10L, 10R are attached to a living body based on changes in the oscillation frequency of the electrical vibrations oscillated by the oscillator circuit 59. That is, the signal processing unit 561 detects changes in the amount of charge in each of the electrode assemblies 10L, 10R due to changes in the frequency of the oscillator circuit 59, and determines whether the electrode assemblies 10L, 10R are in contact with the ear canal of the living body.

[0072] The biopotential sensor 100D of modification 2-4 can also easily and accurately detect whether the electrode assemblies 10L, 10R are attached to a living body.

[0073] <3. Other Modifications> The technology according to the present disclosure has been described above by giving several embodiments and modifications. However, the technology according to the present disclosure is not limited to the above embodiments, and various modifications are possible.

[0074] For example, in the electrode assembly 10 of the first embodiment, the first elastic portion E1 and the second elastic portion E2 are solid bodies that do not contain cavities or bubbles, but the present disclosure is not limited to this. For example, the first elastic resin of the conductor portion may be a foam that contains bubbles. Similarly, the second elastic resin of the insulator portion may be a solid body that does not contain cavities or bubbles, or may be a foam that contains bubbles.

[0075] Furthermore, in the second embodiment and the like, a wireless earphone-type biopotential sensor 100 and the like have been described as examples of biopotential sensors, but the present disclosure is not limited to this. The biopotential sensor of the present disclosure may be provided as part of a head-mounted display 200 shown in Fig. 15, for example. In the head-mounted display 200, the electrode body 10 can be provided on the inner surfaces of the pad portion 201 and the band portion 202, for example.

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

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

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

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

[0080] Terms used throughout this specification and the appended claims should be interpreted as "open-ended" terms. For example, the terms "including" or "including" should be interpreted as "not limited to the manner described as including." The term "having" should be interpreted as "not limited to the manner described as having."

[0081] The terms used in this specification include terms that are used merely for the convenience of description and are not intended to limit the configuration or operation. For example, terms such as "right," "left," "upper," and "lower" merely indicate directions in the drawings to which reference is made. Furthermore, the terms "inner" and "outer" merely indicate directions toward and away from the center of a focused element, respectively. The same applies to similar terms and terms of a similar meaning.

[0082] The technology according to the present disclosure can also have the following configuration: A biopotential electrode body according to the present disclosure having the following configuration has high mechanical strength and is suitable for obtaining a larger amount of biological information. Note that the effects achieved by the technology according to the present disclosure are not necessarily limited to the effects described herein, and may be any of the effects described in the present disclosure. (1) a plurality of conductive portions each including a contact surface that can come into contact with a living body; one or more insulating portions that electrically insulate the plurality of conductive portions from one another; and the conductor 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 conductors and the second particles are insulators. The biopotential electrode according to (1) above. (3) The first elastic resin and the second elastic resin are insulators. The biopotential electrode according to (2) above. (4) The first elastic resin and the second elastic resin are both substantially the same material. The biopotential electrode according to (3) above. (5) The first particles include carbon particles or metal particles. A biopotential electrode according to any one of (1) to (4) above. (6) The metal particles are made of at least one of gold (Au), silver (Ag), and copper (Cu). The biopotential electrode according to (5) above. (7) The first particles include metal particles and a metal compound that covers at least a portion of the surface of the metal particles. A biopotential electrode according to any one of (1) to (6) above. (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 according to (7) above. (9) The first particle includes a base particle and an organic conductive polymer that covers at least a portion of the surface of the base particle. A biopotential electrode according to any one of (1) to (8) above. (10) The organic conductive polymer includes at least one selected from the group consisting of PEDOT-PSS, polypyrrole, polyacetylene, polyphenylene vinylene, polythiophene, polythiol, and polyaniline, and analogs thereof. The biopotential electrode according to (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, polycarbonate resin, and copolymers thereof. A biopotential electrode according to any one of (1) to (10) above. (12) The first elastic resin and the second elastic resin are natural rubber or diene rubber. A biopotential electrode according to any one of (1) to (10) above. (13) The first elastic resin and the second elastic resin of the base resin layer are thermosetting elastomers containing one selected from the group consisting of silicone resins and polyurethane resins. A biopotential electrode according to any one of (1) to (10) above. (14) The second particles are made of titanium oxide. A biopotential electrode according to any one of (1) to (13) above. (15) the plurality of conductive portions and the one or more insulator portions collectively form a generally cylindrical cylindrical structure; The conductive portions and the insulating portions are interleaved in the circumferential direction of the cylindrical structure. A biopotential electrode according to any one of (1) to (14) above. (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. A biopotential electrode according to any one of (1) to (14) above. (17) A biopotential sensor including a biopotential electrode body, The biopotential electrode assembly a plurality of conductive portions each including a contact surface that can come into contact with a living body; one or more insulating portions that electrically insulate the plurality of conductive portions from one another; and the conductor 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 that measures the potential of the living body, The second conductive portion is a ground terminal. The biopotential electrode according to (17) above. (19) further comprising a differential amplifier circuit; the plurality of conductor portions include a first conductor portion and a second conductor portion; the first conductor portion is a measurement terminal that measures the potential of the living body, the second conductive portion is a reference terminal for measuring a reference potential; The differential amplifier circuit detects the difference between the potential of the living body and the reference potential. The biopotential electrode according to (17) or (18) above. (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. The biopotential sensor according to (17) above. (twenty one) the plurality of conductor portions include a first conductor portion and a second conductor portion; The determination unit determines that the biopotential electrode assembly 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. The biopotential sensor according to (20) above. (twenty two) The determination unit determines whether the biopotential electrode unit is attached to the living body based on a real part of a measured value of the impedance of the living body. The biopotential sensor according to (21) above. (twenty three) The device further includes a current supply unit that supplies a current having a frequency greater than 0 and equal to or less than 1000 Hz between the first conductive portion and the second conductive portion. The biopotential sensor according to (21) or (22) above. (twenty four) an oscillation circuit that generates an electrical oscillation; a determination unit that determines 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 The biopotential sensor according to (17) above. [Explanation of symbols]

[0083] 1...electrode unit, 10 (10L, 10R)...electrode body, 11 (11L, 11R)...first conductor portion, 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 portion, E1L, E1R...first elastic portion, C2L, C2R...second core portion, E2L, E2R...second elastic portion, 12 (12L, 12R)...second conductor portion, Z1L, Z1R...first insulator portion, Z2L, Z2R...second insulator portion, 10HL, 10HR...through hole, K1L to K4L, K1R to K4R...interface, 100...biopotential sensor.

Claims

1. a plurality of conductive portions each including a contact surface that can come into contact with a living body; one or more insulating portions that electrically insulate the plurality of conductor portions from one another; and 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; the plurality of conductive portions and the one or more insulating portions collectively form a generally cylindrical cylindrical structure; The volume ratio of one of the plurality of conductive portions is higher than the volume ratio of the other conductive portions. Biopotential electrode body.

2. The first particles are conductive and the second particles are insulators. The biopotential electrode assembly of claim 1 .

3. The first elastic resin and the second elastic resin are insulators. The biopotential electrode assembly of claim 2.

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

5. The first particles include carbon particles or metal particles. 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 assembly of 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. 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 that covers at least a portion of the surface of the base particle. The biopotential electrode assembly of claim 1 .

10. The organic conductive polymer includes at least one selected from the group consisting of PEDOT-PSS, polypyrrole, polyacetylene, polyphenylene vinylene, polythiophene, polythiol, and polyaniline, and analogs thereof.

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. The biopotential electrode assembly of claim 1 .

12. The first elastic resin and the second elastic resin are natural rubber or diene rubber. The biopotential electrode assembly of claim 1 .

13. The first elastic resin and the second elastic resin are thermosetting elastomers containing one selected from the group consisting of silicone resins and polyurethane resins. The biopotential electrode assembly of claim 1 .

14. The second particles are made of titanium oxide. The biopotential electrode assembly of claim 1 .

15. The conductive portions and the insulating portions are interleaved in the circumferential direction of the cylindrical structure. The biopotential electrode assembly of claim 1 .

16. The plurality of conductive portions are separated axially of the cylindrical structure by the one or more insulating portions. The biopotential electrode assembly of claim 1 .

17. At least the plurality of conductive portions among the plurality of conductive portions and the one or more insulating portions include a cavity therein. The biopotential electrode assembly of claim 1 .

18. A biopotential sensor including a biopotential electrode body, The biopotential electrode assembly a plurality of conductive portions each including a contact surface that can come into contact with a living body; one or more insulating portions that electrically insulate the plurality of conductor portions from one another; and 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; the plurality of conductive portions and the one or more insulating portions collectively form a generally cylindrical cylindrical structure; The volume ratio of one of the plurality of conductive portions is higher than the volume ratio of the other conductive portions. Biopotential sensors.

19. the plurality of conductor portions include a first conductor portion and a second conductor portion; the first conductor portion is a measurement terminal that measures the potential of the living body, The second conductive portion is a ground terminal.

20. The biopotential sensor of claim 18.

20. further comprising a differential amplifier circuit; the plurality of conductor portions include a first conductor portion and a second conductor portion; the first conductor portion is a measurement terminal that measures the potential of the living body, the second conductive portion is a reference terminal for measuring a reference potential; The differential amplifier circuit detects the difference between the potential of the living body and the reference potential.

20. The biopotential sensor of claim 18.

21. 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 18.

22. the plurality of conductor portions include a first conductor portion and a second conductor portion; The determination unit determines that the biopotential electrode assembly 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.

22. The biopotential sensor of claim 21.

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

23. The biopotential sensor of claim 22.

24. a current supply unit that supplies a current having a frequency greater than 0 and not greater than 1000 Hz between the first conductive portion and the second conductive portion; 23. The biopotential sensor of claim 22.

25. an oscillation circuit that generates an electrical oscillation; a determination unit that determines 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 18.

26. A plurality of the biopotential electrode assemblies are provided, the plurality of biopotential electrode bodies include a first electrode body and a second electrode body having different configurations; the first electrode body has the plurality of conductive portions and the one or more insulating portions, the plurality of conductive portions and the one or more insulating portions collectively form a generally cylindrical cylindrical structure; In the first electrode body, a volume ratio occupied by one of the plurality of conductive portions is higher than a volume ratio occupied by another conductive portion.

20. The biopotential sensor of claim 18.

27. The second electrode body has a single conductive portion that forms a substantially cylindrical structure, and the single conductive portion is provided over the entire circumferential direction of the cylindrical structure.

27. The biopotential sensor of claim 26.

28. The conductive portions and the insulating portions are interleaved in the circumferential direction of the cylindrical structure.

20. The biopotential sensor of claim 18.

29. The plurality of conductive portions are separated axially of the cylindrical structure by the one or more insulating portions.

20. The biopotential sensor of claim 18.

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