JP2016163688A - Brain wave measuring electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brain wave measuring electrode capable of sufficiently securing conduction by being brought into contact with a scalp without using conductive paste and reducing the burden of a subject.SOLUTION: A brain wave measuring electrode 10 including a base material 12 which is formed by an elastic body, and a structure formed on the surface of the base material. The base material 12 includes projection parts 12b having a contact surface 12c to be brought into contact with a scalp, and the structure includes a plurality of nanocarbon materials, forms a network structure in which the plurality of nanocarbon materials are mutually connected, and is fixed to the surface of the base material 12.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electroencephalogram measurement electrode.

  As a conventional electroencephalogram measurement electrode, a type in which a conductive paste is interposed between a subject's scalp and an electrode is often used. In addition to reducing the contact impedance between the scalp and the electrode, the conductive paste has the effect of fixing the position of the measurement site, but it requires work removal because it requires removal after measurement. .

  In recent years, an electrode (dry electrode) that can ensure low contact impedance without using a conductive paste has been developed. As the dry electrode, for example, a multi-pin type dry electrode (for example, Non-Patent Document 1) used by attaching to a hair band or a multi-pin type dry electrode (for example, Non-Patent Document 2) used by attaching to a head cap has been proposed. ing. In these dry electrodes, the multi-pin is made of a hard metal.

  In addition, in order to reduce the burden on the subject, an electroencephalogram measurement electrode (for example, Patent Document 1) provided with a metal contact portion at the tip of a protruding portion made of rubber, or a metal spring is used. There has been proposed an electroencephalogram measurement electrode in which a spherical tip can be expanded, contracted and swiveled (for example, Patent Document 2).

JP 2013-111361 A JP 2013-240485 A

Manabu Honda, CREST, Strategic Creativity Research Promotion Project, Research Area “Advanced Integrated Sensing Technology”, Research Subject “Wearable Core Functional Integrated Sensing System to Create a Safe Information Environment in the Brain” g-tec Active Dry Electrode “g.SAHARA”, Internet <URL: http://www.gtec.at/Products/Electrodes-and-Sensors/g.SAHARA-Specs-Features>

  The electrodes of Non-Patent Documents 1 and 2 have a problem that the test subject feels uncomfortable and the burden on the scalp is large, although conduction is sufficiently ensured because the multi-pin is made of a hard metal.

  In the electrode of Patent Document 1, a large amount of a conductive material is blended in order to impart desired conductivity to a protrusion made of rubber. As a result, the inherent flexibility and cushioning properties of the rubber are lowered and become hard, which leads to the pain of the subject when brought into contact with the scalp. In addition, since it is hard, it has poor adhesion to the scalp, making it difficult to accurately measure brain waves. In the case where an expensive conductive material is used, the manufacturing cost cannot be suppressed.

  In the electrode of Patent Document 2, due to the complexity of the structure, poor continuity may occur at the contact point, and electroencephalogram measurement may not be performed well. In addition, since the structure is complicated, the manufacturing cost is high and it is not suitable for mass production.

  Therefore, an object of the present invention is to provide an electroencephalogram measurement electrode that can sufficiently ensure electrical conduction by contacting the scalp without using a conductive paste and that can reduce the burden on the subject.

  An electroencephalogram measurement electrode according to the present invention is an electroencephalogram measurement electrode comprising a base material made of an elastic body and a structure formed on a surface of the base material, wherein the base material contacts the scalp. The structure includes a plurality of nanocarbon materials, and the plurality of nanocarbon materials form a network structure connected to each other and are fixed to the surface of the base material. It is characterized by.

  According to the present invention, the electroencephalogram measurement electrode includes a base material made of an elastic body, and a part of the protrusion (contact surface) of the base material contacts the scalp of the subject. In the structure, nano-carbon materials are connected to form a network structure. Such a structure is attached and fixed to the base material. Thereby, it can contact with a scalp without using an electrically conductive paste, and can fully ensure conduction | electrical_connection. Since the elastic body has flexibility and cushioning properties, even when pressure is applied, it does not give the subject discomfort such as pain, and the burden can be reduced.

It is a perspective view which shows the structure of the electrode for electroencephalogram measurement which concerns on this embodiment. It is a perspective view which shows the structure of the electrode for electroencephalogram measurement which concerns on a modification. It is a perspective view which shows the electrode for electroencephalogram measurement produced in the Example. It is a figure which shows the base material in the electrode for electroencephalogram measurement produced in the Example, FIG. 4A is a top view, FIG. 4B is AA sectional drawing in FIG. 4A. It is the schematic which shows the structure of the active electrode used for the electrode contact resistance measurement.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1. Overall Configuration As shown in FIG. 1, the electroencephalogram measurement electrode 10 includes a base material 12 having a disk-shaped support 12 a and a protrusion 12 b formed on one surface of the support 12 a. A structure (not shown) is formed on the surface of the base material 12. This structure has conductivity, and a conductive path is formed on the surface of the base material 12 by this structure.

  In the case of this embodiment, the base material 12 is formed of an elastic body having flexibility and cushioning properties, and is formed of, for example, a thermoplastic elastomer. More specifically, examples of the thermoplastic elastomer include urethane thermoplastic elastomers. When the Shore A hardness of the base material 12 is too large, the subject feels pain when the protruding portion 12b is brought into contact with the scalp. On the other hand, when the Shore A hardness of the base material 12 is too small, the protrusion 12b pressed against the scalp is excessively curved, and the contact between the scalp and the protrusion 12b becomes unstable. The Shore A hardness of the base material 12 is preferably about 68 to 75A. The Shore A hardness of the base material 12 formed of a urethane-based thermoplastic elastomer is, for example, about 75A.

  Although the number of protrusions 12b in the base material 12 is not limited, it is desirable that a plurality of protrusions 12b are provided. In the present embodiment, the protruding portion 12b has a cylindrical shape and is integrally formed of the same material as that of the support portion 12a. The tip of the protrusion 12b has a contact surface 12c that contacts the scalp. In practice, the scalp is in contact with the structure formed on the contact surface 12c.

  In the present embodiment, the electroencephalogram measurement electrode 10 includes a base material 12 made of an elastic body and a structure on the surface of the base material 12, and does not include a metal member.

  In the base material 12 made of an elastic body, for example, the support portion 12a can have a diameter of about 5 to 20 mm and a thickness of about 1 to 10 mm. About the protrusion part 12b, a diameter can be about 1-10 mm and height can be about 5-20 mm, for example.

  A structure (not shown) on the surface of the base material 12 includes a plurality of nanocarbon materials. In this embodiment, a carbon nanotube (hereinafter referred to as CNT) is used as the nanocarbon material. The plurality of CNTs are connected to each other to form a structure having a network structure. The connection here includes physical connection (simple contact). Since CNTs themselves have high conductivity, they can maintain high conductivity even after becoming a structure having a network structure of a plurality of CNTs, and are preferably used as the electroencephalogram measurement electrode 10.

  A structure having a network structure of CNT may be formed by mixing a general adhesive or the like with CNT and fixed to the surface of the base material 12 or van der Waals force possessed by CNT without using an adhesive or the like. It may be formed by using and attached directly to the surface of the base material 12 and fixed.

  When not using an adhesive or the like, since the surface of the CNT fiber itself is not covered with an adhesive or the like, the CNTs can be directly connected without inclusions, and a structure having a network structure can be formed. The high conductivity of CNT has the advantage that it can be used for the electroencephalogram measurement electrode 10 as it is.

CNT is manufactured by a general arc discharge method, a vapor phase growth method, a laser evaporation method, or the like. For example, a CNT produced by a vapor phase growth method using a catalyst containing a metal such as Co and Mg and using a gas containing CO (carbon monoxide) and H ₂ as a raw material can be used. Further, CNTs can be used not only in a tube shape but also those whose shape has been changed by heating or the like.

2. Manufacturing Method Next, a manufacturing method of the electroencephalogram measurement electrode 10 will be described. The electroencephalogram measurement electrode 10 can be manufactured by preparing a dispersion containing CNTs and forming a structure on the surface of the base material 12 using the dispersion.

  Prior to preparation of the dispersion, CNTs are pretreated with a mixed acid. As the mixed acid, for example, a 1: 1 mixed solvent of nitric acid and sulfuric acid can be used. After the CNTs are added to the mixed solvent, the CNTs are stirred and then irradiated with ultrasonic waves to isolate and disperse the CNTs. Thereafter, the CNT is taken out by filtration under reduced pressure, and the CNT surface is neutralized using ammonia water or the like. And after washing | cleaning the surface with a pure water, it dries and obtains powdery CNT.

  A dispersion is obtained by ultrasonic treatment or high-pressure dispersion treatment so that the powdery CNTs subjected to the pretreatment as described above have a concentration of, for example, 0.01 to 10 wt%. The concentration of CNT in the dispersion is more preferably about 0.1 to 5 wt%, and most preferably about 0.5 to 2 wt%. As the solvent, N, N-dimethylformamide (DMF), various alcohols, and the like can be used. In addition, you may use for this dispersion liquid adding suitable additives, such as a dispersing agent, surfactant, and an adhesive agent. However, when such additives are added to the dispersion, these additives may coat the fiber surface of the CNT, which may impair the original conductivity of the CNT. From these facts, it can be said that it is preferable from the viewpoint of improving conductivity to form a structure having a network structure of CNTs with a dispersion without adding the above additives and fix the structure to the base material 12.

  Next, the elastic body as the base material 12 is immersed in the dispersion. When the above-mentioned additive is not added to the dispersion, the CNT forms a structure having a network structure of the CNT by van der Waals force acting between the surface of the base material 12, and the protrusion in the base material 12. It adheres directly to the surface of the part 12b, the support part 12a and the contact surface 12c. Further, when an adhesive or the like is added to the dispersion liquid, in addition to the above van der Waals force, a force such as an adhesive is also taken into account, and the dispersion liquid strongly adheres to the base material 12.

  Thereafter, the base material 12 is pulled out of the dispersion and dried, so that the CNTs adhere and are fixed to the surface of the base material 12. In this way, a structure having a network structure in which CNTs are connected to each other is formed on the surface of the base material 12. A structure having a predetermined thickness can be obtained by repeating the steps of dipping and drying.

  When the base material 12 is immersed in the dispersion liquid as described above, the CNTs adhere to the surfaces of the protruding portion 12b, the support portion 12a, and the contact surface 12c in the base material 12. Therefore, it is possible to easily form the electroencephalogram measurement electrode 10 in which CNTs adhere to the surface of the base material 12.

3. Action and Effect In the electroencephalogram measurement electrode 10 configured as described above, a structure is formed on the surface of the base material 12 having the protruding portion 12b, and a conductive path is formed on the surface of the base material 12 by the structure. Is done. When measuring an electroencephalogram using such an electroencephalogram measurement electrode 10, the protrusion 12b enters between the hairs and contacts the scalp at the contact surface. Even without using a conductive paste, it is possible to ensure electrical conduction between the electroencephalogram measurement electrode 10 and the head of the subject and reduce the contact impedance to an extremely low level. As a result, the electroencephalogram measurement electrode 10 can accurately detect a weak electric signal from the head.

  In addition, the base material 12 including the protruding portion 12b is made of an elastic body and has flexibility and cushioning properties. The contact between the projecting portion 12b and the head of the subject prevents the subject from feeling uncomfortable even when pressure is applied, and the burden is reduced.

  In the case of this embodiment, since the structure forms a network structure in which a plurality of CNTs are connected to each other, the structure can exhibit electrical conductivity that is a function derived from CNTs. In particular, when a structure having a network structure is formed by directly connecting a plurality of CNTs with nothing intervening, the electrical conductivity thereof is particularly high, and the electroencephalogram measurement electrode 10 is suitable.

  In addition, since the conductive path is formed on the surface of the base material 12, the measured electroencephalogram can be efficiently transmitted as compared with the case where the conductive path exists inside the base material 12.

  In addition, when the structure is directly connected to CNTs without using an adhesive or the like to form a network and is fixed to the base material 12, that is, the structure is formed without using an adhesive or the like. Since the structure is fixed to the base material 12, in addition to good conductivity, the flexibility and cushioning properties of the base material 12 can be maintained. Therefore, the electroencephalogram measurement electrode 10 can reduce the burden on the subject by having flexibility and cushioning properties as a whole. Since the structure exists on the surface of the base material 12, the amount of CNT used can be minimized, leading to a reduction in manufacturing cost.

  The electroencephalogram measurement electrode 10 according to the present embodiment is composed of a base material 12 made of an elastic body and a structure on the surface of the base material 12. Since a metal member is not included, X-ray computed tomography (CT) or nuclear magnetic resonance imaging (MRI) is performed with the electroencephalogram measurement electrode 10 according to the present embodiment mounted on the head. Thus, even if image information is acquired, the occurrence of artifacts can be prevented. Therefore, the electroencephalogram measurement electrode 10 can simultaneously acquire image information obtained by X-ray CT, MRI, or the like and an electroencephalogram by the electroencephalogram electrode.

  Since the metal member is not included, the electroencephalogram measurement electrode 10 can be used for a subject having metal allergy. The electroencephalogram measurement electrode 10 according to the present embodiment can be disposable, and is excellent in terms of hygiene. The base material 12 made of an elastic body can be integrally formed with the support portion 12a and the protruding portion 12b. Such an electroencephalogram measurement electrode 10 is excellent in mass productivity and can reduce the manufacturing cost.

4). The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the gist of the present invention.

  In the above embodiment, CNT is used as the nanocarbon material forming the structure. However, the present invention is not limited to CNT, and graphene can also be used. Graphene is a nanocarbon material having high conductivity like CNT. The electroencephalogram measurement electrode 10 can be obtained by attaching graphene to the surfaces of the protruding portion 12b, the support portion 12a, and the contact surface 12c of the base material 12 by the same method as described above except that CNT is changed to graphene. .

  Graphene can be dispersed in a solvent and used as a dispersion having a concentration of 0.01 to 10 wt%, for example. The concentration of graphene in the dispersion is more preferably about 0.1 to 5 wt%, and most preferably about 0.5 to 2 wt%.

  Moreover, although the said embodiment demonstrated the case where the base material 12 was formed with a thermoplastic elastomer, this invention is not restricted to this, The base material 12 can be formed using arbitrary elastic bodies. For example, the base material 12 may be formed of resin, rubber, or the like. Examples of the thermoplastic elastomer include olefin-based thermoplastic elastomer (TPO), styrene-based thermoplastic elastomer, ester-based thermoplastic elastomer (TPC), urethane-based thermoplastic elastomer (TPU), polyamide-based thermoplastic elastomer (TPAE), and vinyl chloride. Examples of resins include AS resin, ABS resin, epoxy resin, tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and the like. ), Hexafluoropropylene / ethylene copolymer (EFEP), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene / ethylene copolymer (EC) FE), polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene sebacamide (nylon 610), polyhexamethylene deca Mido (nylon 612), polydodecanamide (nylon 12), polyundecanamide (nylon 11), polyhexamethylene terephthalamide (nylon 6T), polyxylylene adipamide (nylon XD6), polynonamethylene terephthalamide (nylon) 9T), polyundecane methylene terephthalamide (nylon 11T), polydecane methylene decanamide (nylon 1010), polydecane methylenedodecanamide (nylon 1012) amide elastomer (TPA), polybutylene terephthalate PBT), polybutylene naphthalate (PBN), polyethylene naphthalate (PEN) polycarbonate (PC), linear low density polyethylene (LLDPE), ultra low density polyethylene, low density polyethylene (LDPE), medium density polyethylene (MDPE) , High density polyethylene (HDPE), cross-linked polyethylene, ethylene / vinyl acetate copolymer (EVA), ethylene / vinyl alcohol copolymer (EVOH), butenediol / vinyl alcohol copolymer (BVOH), polyvinyl alcohol (PVA) , Polybutene (PB), urethane elastomer (TPU), ester elastomer (TPC), olefin elastomer (TPO), styrene elastomer (TPS), modified polyphenylene ether (modified PPE), liquid crystal polymer LCP), cycloolefin copolymer (COC), polyether ketone (PEK), polyglycolic acid (PGA), polyarylate (PAR), polymethylpentene (PMP), polyether ether ketone (PEEK), polyether sulfone ( PES), polyethylene terephthalate (PET), phenol resin (PF), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polyimide (PI), polyetherimide (PEI), acrylic resin (PMMA), polyacetal ( POM), polypropylene (PP), polyphenylene sulfide (PPS), polystyrene (PS), polysulfone (PSU), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and the like.

  Examples of rubber include natural rubber (NR), ethylene / propylene rubber (EPM, EPDM), chloroprene rubber (CR), butyl rubber (IIR), polyurethane rubber (U), silicone rubber (VMQ, FVMQ), and acrylic rubber (ACM). ), Epichlorohydrin rubber (ECO), fluorine-based rubber (FKM, FEPM, FFKM), nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), chlorinated polyethylene (CPE), chlorosulfonated polyethylene (CSM), Examples thereof include butadiene rubber (BR) and styrene / butadiene rubber (SBR).

  The Shore A hardness of the base material 12 formed of an olefin-based thermoplastic elastomer (TPO) is, for example, about 73. The Shore A hardness of the base material 12 formed of ester thermoplastic elastomer (TPC) is about 68, for example. The Shore A hardness of the base material 12 formed of a polyamide-based thermoplastic elastomer (TPAE) is, for example, about 75A.

  The support part 12a and the protrusion part 12b in the base material 12 may use different materials by multicolor molding, insert molding, or the like, as long as flexibility and cushioning properties are not impaired.

  Further, the base material 12 is formed by solidifying a foam material having cushioning properties such as urethane foam, a porous material such as wood or cork, a material made into a thread shape based on various fibers, or a material in which fibers are woven or knitted. You may form with a material and a nonwoven material. In short, any material exhibiting elasticity can be suitably used without being limited to the above materials.

  In particular, when a fiber material, a porous material, a foam material, or the like is used for the base material 12, since the CNT fibers are easily entangled with the unevenness of the surface, each CNT is applied to the surface of the base material 12 without using an adhesive. A structure having a CNT network structure can be formed while a plurality of fibers are entangled with each other, and can be directly fixed to the base material 12 at the same time. Thereby, the electroencephalogram measurement electrode 10 with improved conductivity can be obtained as described above.

  The protruding portion 12b in the base material 12 is not limited to a cylindrical shape, and may be a polygonal column shape, a polygonal pyramid shape, or the like. Furthermore, the protrusion part 12b can also be formed in the shape which consists of an axial part and a contact part which are demonstrated later.

  When consideration about the artifact is not required, a metal member such as a metal plate may be included in a part of the electroencephalogram measurement electrode 10 as long as the flexibility and cushioning properties of the protrusion 12b are not impaired. For example, a metal plate can be disposed on the bottom surface of the support portion 12a in the base material 12. By providing the metal plate, an electric signal can be easily transmitted. In this case, as long as a conducting wire for ensuring electrical continuity with the projecting portion 12b is provided, the structure does not necessarily have to be formed on the surface of the supporting portion 12a.

The shape of the support part 12a in the base material 12 and the arrangement of the protruding parts 12b can be changed as appropriate. For example, as illustrated in FIG. 2, the base material 22 may be formed by arranging a protruding portion 22 b along the long side and the short side on one surface of a rectangular plate-like support portion 22 a. In brain wave measurement electrode 20 shown in FIG. 2, the protruding portion 22b has a slender shaft portion 22b ₁ diameter, and a contact portion 22b ₂ Metropolitan provided at the tip of the shaft portion 22b _1. In this case, the end face of the contact portion 22b ₂ is the contact surface 22c.

  As long as a change in the weak potential of the electroencephalogram can be captured, the shape and number of the protruding portions, the shape and area of the contact surface, and the like are not particularly limited and can be changed as appropriate. The electroencephalogram measurement electrode 20 in which the structure as described above is formed on the surface of the base material 12 having a protrusion and made of an elastic body can obtain the same effect.

<Preparation of electroencephalogram measurement electrode>
The base material 12 was injection-molded using a polyamide-based thermoplastic elastomer as a thermoplastic elastomer, and an electroencephalogram measurement electrode 10 as shown in FIG. 3 was produced. Specifically, the polyamide-based thermoplastic elastomer used is Pebax 2533SA01 manufactured by Arkema Co., Ltd. The base material 12 includes a disk-shaped support portion 12a and three projecting portions 12b. On one surface of the support portion 12a, a cylindrical portion 12e is provided concentrically with the support portion 12a. The three protrusions 12b are equally arranged so as to extend from the cylindrical portion 12e. The outer diameter d1 of the support part 12a is 10 mm. The cylindrical portion 12e has a thickness center diameter d2 of 5.0 mm (see FIG. 4A).

  In the base material 12, the distance h1 from the end surface 12d of the support portion 12a to the contact surface 12c is 10 mm, the thickness t1 of the support portion 12a is 2 mm, and the height h2 of the cylindrical portion 12e is 2.5 mm (see FIG. 4B). ). The cylindrical portion 12e has a base wall thickness t2 of 1 mm and a front wall thickness t3 of 0.8 mm. The three protrusions 12b have a tapered columnar shape. The protrusion 12b has a proximal end diameter d4 of 2 mm and a distal end diameter d5 of 1 mm. The Shore A hardness of the base material 12 was 75.

  Using the CNT dispersion liquid having a concentration of 0.6 wt%, the base material 12 was subjected to CNT coating by the method described above, and the electroencephalogram measurement electrode 10 of Example 1 was produced. In addition, the electroencephalogram measurement electrode 10 of Example 2 was manufactured by applying graphene coating to the base material 12 in the same manner except that a 1 wt% concentration of graphene dispersion was used.

<Measurement of impedance>
The impedance of the electroencephalogram measurement electrode 10 of Example 1 was measured using an LCR meter (IM3590 manufactured by Hioki Electric Co., Ltd.). The impedance was measured by sandwiching two predetermined portions of the base material 12 with clips. The frequency was 10 Hz. The impedance measured by sandwiching two places (on the diameter) of the outer periphery of the support portion 12a with clips was 600Ω. The impedance measured by sandwiching one point on the outer periphery of the support portion 12a and the tip of the protruding portion 12b closest to this point with a clip was 6 kΩ. If the impedance is about 30 KΩ or less, it can be suitably used as an electroencephalogram measurement electrode.

The impedance of the polyamide-based thermoplastic elastomer alone constituting the base material 12 is 1 × 10 ¹² Ω or more. By applying CNT coating to such a base material 12, the impedance could be greatly reduced. When graphene coating is applied to the same base material 12, the impedance similarly decreases.

<Measurement of electrode contact resistance>
The electroencephalogram measurement electrode 10 of the example was combined with an active electrode (dish electrode), and electrode contact resistance was measured for the forehead and the hair portion. For measurement, a wireless bioelectric signal measuring device (Polymate Mini) manufactured by Miyuki Giken was used.

  As shown in FIG. 5, the active electrode 30 has a dish surface 30 a on one surface, a terminal retainer 34 for attaching the electroencephalogram measurement electrode 10 to the dish surface 30 a on the other surface, and a conducting wire 32 is connected. Yes. The electroencephalogram measurement electrode 10 is attached so that the end surface 12 d (see FIG. 4B) of the support portion 12 a of the base material 12 is in contact with the dish surface 30 a of the active electrode 30.

  The reference and ground electrodes were connected to the right ear. At this time, in order to reduce the contact resistance of the reference, a polishing gel was used for the right ear and a conductive paste was applied to the electrode. As a result, the reference electrode contact resistance was 10 KΩ.

  The contact surface 12c of the electroencephalogram measurement electrode 10 was brought into contact with the forehead portion or the hair portion, and the electrode contact resistance relative to the reference was measured. The forehead part was measured by reducing the contact resistance by using a polishing gel before the measurement. In the electroencephalogram measurement electrode 10 of Example 1, the electrode contact resistance at the forehead portion was 25 kΩ, and the electrode contact resistance at the hair portion was 30 kΩ. In the electroencephalogram measurement electrode 10 of Example 2, the electrode contact resistance at the forehead portion was 40 kΩ, and the electrode contact resistance at the hair portion was 80 kΩ. It was confirmed that the electroencephalogram measurement electrode 10 of the example had a low electrode contact resistance even in the hair portion.

  For comparison, the electrode contact resistance was measured for the forehead portion and the hair portion in the same manner using only the active electrode 30. Although the electrical contact resistance at the forehead was similar to that of the electroencephalogram measurement electrode 10 of the example, the hair portion was a large value of 300 kΩ or more. The active electrode 30 cannot contact the scalp avoiding the hair. Only with the active electrode 30, the hair becomes an obstacle, and the electrode contact resistance of the hair portion becomes high, so that the electroencephalogram cannot be measured accurately.

  In the electroencephalogram measurement electrode 10 of the embodiment, the protruding portion 12b made of an elastic body reaches the scalp while scraping the hair of the head hair portion, and the contact surface 12c of the protruding portion 12b contacts the scalp without being obstructed by the hair. Since the contact surface 12c has a structure having a network structure in which a plurality of CNTs are connected to each other, sufficient conductivity can be ensured without a conductive paste. In the case of using the electroencephalogram measurement electrode 10 of the example, a low resistance value can be obtained even in the hair portion, and the electroencephalogram can be measured with high accuracy. Moreover, since the electroencephalogram measurement electrode 10 includes the protruding portion 12b made of an elastic body, the burden on the subject can be reduced.

10, 20 Electroencephalogram measurement electrode 12, 22 Base material 12a, 22a Support portion 12b, 22b Protruding portion 12c, 22c Contact surface 12d End surface of 12a 12e Cylindrical portion 22b ₁ shaft portion 22b ₂ contact portion 30 Active electrode 30a Plate surface 34 Terminal Holding

Claims (5)

An electroencephalogram measurement electrode comprising a base material made of an elastic body and a structure formed on the surface of the base material,
The base material includes a protrusion having a contact surface that contacts the scalp,
The structure includes a plurality of nanocarbon materials, and the plurality of nanocarbon materials form a network structure connected to each other and are fixed to the surface of the base material. Measuring electrode.   The electroencephalogram measurement electrode according to claim 1, wherein the base material includes a support portion that supports the protruding portion, and the protruding portion is integrally formed with the support portion.   3. The electroencephalogram measurement electrode according to claim 1, wherein the elastic body is selected from a resin, a thermoplastic elastomer, and rubber.   The electroencephalogram measurement electrode according to any one of claims 1 to 3, wherein the plurality of nanocarbon materials are selected from carbon nanotubes and graphene. The electrode for electroencephalogram measurement according to any one of claims 1 to 4, wherein a metal member is not included.

Images