Bioelectrode

Abstract

A bioelectrode (1) includes a base portion (21) including a mounting surface (21a), and a plurality of electrode protrusions (22) protruding from the mounting surface (21a) and including conductive particles and a rubber material, the plurality of electrode protrusions being configured to be in contact with a detection object to detect a biometric signal, a plurality of electrode protrusions (22) are arranged on a mounting surface in a circular manner, in which a central axis (O2) of each of the plurality of electrode protrusions (22) is inclined with respect to a normal (O1) passing through a center of the mounting surface, a center of a distal end of each of the plurality of electrode protrusions (22) is arranged further radially outward from a center of the mounting surface than a center of a corresponding proximal end, and wherein each of the plurality of electrode protrusions (22) is hollow.

Description

Technical Field

[0001] The present disclosure relates to a bioelectrode. Background Art

[0002] There is known a bioelectrode for obtaining biometric information such as electroencephalogram, electrocardiogram, and electromyogram based on changes in potential in a living body. As a bioelectrode, for example, the bioelectrode described in Patent Document 1 can be cited.

[0003] The bioelectrode described in Patent Document 1 includes a support member and a plurality of electrode members. The support member supports the plurality of electrode members. The plurality of electrode members are segments that contact the body of the subject and protrude from the support member in a brush-like manner. Further, the materials of the support member and the plurality of electrode members are conductive rubber. The conductive rubber includes silicone rubber and silver powder.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: WO 2018 / 230445 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] Biometric signals such as electroencephalogram are weak signals of several tens of μV. Generally, in order to detect such signals with high sensitivity, a large amount of metal powder such as silver powder is used as the material of the bioelectrode. When a large amount of metal powder is used, the material hardness increases and the material cost increases. When the material hardness increases, discomfort may be felt according to the condition of wearing the electrode for a long time. Therefore, it may not be possible to obtain a desired measurement result.

[0009] Solutions to the Problems

[0010] To solve the above problems, a bioelectrode according to an aspect of the present disclosure includes a base and a plurality of electrode protrusions. The base includes a mounting surface. The plurality of electrode protrusions protrude from the mounting surface and include conductive particles and a rubber material. The plurality of electrode protrusions are configured to contact a detection object to detect a biometric signal. Among them, the plurality of electrode protrusions are arranged in a circular manner on the mounting surface. Among them, the central axis of each of the plurality of electrode protrusions is inclined with respect to the normal line passing through the center of the mounting surface. Among them, the center of the distal end of each of the plurality of electrode protrusions is arranged to be more radially outward from the center of the mounting surface than the center of the corresponding proximal end. And among them, each of the plurality of electrode protrusions is hollow.

[0011] In addition, a bioelectrode according to another aspect of the present disclosure includes a base and a plurality of electrode protrusions. The base includes a mounting surface. The plurality of electrode protrusions protrude from the mounting surface and include conductive particles and a rubber material. The plurality of electrode protrusions are configured to contact a detection object to detect a biometric signal. Among them, the plurality of electrode protrusions are arranged in a circular manner on the mounting surface. Among them, the central axis of each of the plurality of electrode protrusions is inclined with respect to the normal line passing through the center of the mounting surface. Among them, the center of the distal end of each of the plurality of electrode protrusions is arranged to be more radially outward away from the center of the mounting surface than the center of the mounting surface. Among them, each of the plurality of electrode protrusions includes a hemispherical distal portion and an intermediate portion. The hemispherical distal portion includes a distal end. The intermediate portion is provided between the distal portion and the mounting surface and has a split cylindrical shape. The intermediate portion has a split cylindrical shape obtained by cutting off a radially outer portion from the cylinder along the normal line.

[0012] Effects of the Invention

[0013] According to the present disclosure, the rigidity of the electrode protrusions can be reduced, and the possibility of discomfort when wearing the bioelectrode can be reduced. In addition, the plurality of electrode protrusions flexibly bend to expand outward when wearing the bioelectrode; therefore, the contact area between the electrode protrusions and the measurement site of the subject can be increased. Therefore, a decrease in measurement accuracy can be generally prevented. Description of the Drawings

[0014] Figure 1 is a side view of a bioelectrode according to the first embodiment.

[0015] Figure 2 is a bottom view of a bioelectrode according to the first embodiment.

[0016] Figure 3 is along Figure 2 The cross-sectional view taken along line A1-A1 of.

[0017] Figure 4 is Figure 3 An enlarged view of a part of the plurality of electrode protrusions shown.

[0018] Figure 5 is a diagram showing a cross-section of a part of an electrode member according to the second embodiment.

[0019] Figure 6 is a diagram showing a cross-section of a part of an electrode member according to the third embodiment.

[0020] Figure 7 is a side view of an electrode member according to the fourth embodiment.

[0021] Figure 8Yes Figure 7 The bottom view of the electrode member shown.

[0022] Figure 9 Yes Figure 7 The cross-sectional view of a part of the plurality of electrode protrusions shown.

[0023] Figure 10 The side view of a bioelectrode according to a variant. Detailed Description of the Invention

[0024] Hereinafter, preferred embodiments according to the present disclosure will be described with reference to the accompanying drawings. In addition, the scope of the present disclosure is not limited to these embodiments, unless the following description includes a description specifically limiting the present disclosure.

[0025] 1. First Embodiment

[0026] Figure 1 The side view of the bioelectrode 1 according to the first embodiment. Figure 2 The bottom view of the bioelectrode 1 according to the first embodiment. Figure 3 Yes Figure 2 The cross-sectional view taken along line A1 - A1 of.

[0027] Figure 1 , Figure 2 and Figure 3 The bioelectrode 1 shown is an electrode for detecting a change in potential in a living body such as a human or an animal as a biometric signal. The bioelectrode 1 is used in a state where the bioelectrode 1 is in contact with the surface of the living body to be measured. Although not shown, the bioelectrode 1 is electrically connected to a measuring device that generates biometric information such as an electroencephalogram based on the biometric signal from the bioelectrode 1. Hereinafter, the living body to be measured may be referred to as a subject.

[0028] It should be noted that the use of the bioelectrode 1 is not limited to taking an electroencephalogram. For example, biometric information such as an electrocardiogram and an electromyogram can be measured. Therefore, a part of the living body in contact with the bioelectrode 1 is not limited to the scalp. For example, it can be an arm, a leg, a chest, a back, etc., or alternatively, it can be a hairless area. In addition, the use of the bioelectrode 1 is not limited to the use of measuring biometric signals. For example, it can be used for providing electrical stimulation to a living body.

[0029] As Figure 1 shown, the bioelectrode 1 includes a support member 10, an electrode member 20, and a connector 30. The bioelectrode 1 outputs the biometric signal of the subject from the connector 30 in a state where the distal ends 22t of the plurality of electrode protrusions 22 included in the electrode member 20 are in contact with the body of the subject. Hereinafter, each element of the bioelectrode 1 will be described in turn.

[0030] The support member 10 is a member for supporting the electrode member 20. The support member 10 is made of an insulating material, in other words, a dielectric material. Examples of the insulating material include polymers such as silicone rubber, polyurethane rubber, fluororubber, and terpolymer rubber made of ethylene, propylene, and diene. The terpolymer rubber made of ethylene, propylene, and diene is ethylene propylene diene monomer (EPDM). From the perspective of enhancing the adhesion between the support member 10 and the electrode member 20, preferably, the insulating material is the same polymer as the polymer type constituting the electrode member 20.

[0031] In Figure 1 In the example shown, the shape of the support member 10 is disc-shaped. The support member 10 includes a support surface 10a and a rear surface 10b. The support surface 10a is the surface for supporting the electrode member 20. The rear surface 10b is the surface facing the direction opposite to the direction facing the support surface 10a. Further, as Figure 3 shown, the support member 10 is provided with a through hole S0 and a plurality of first holes S1. Each of the through hole S0 and the first holes S1 is a hole passing through the support member 10 in the thickness direction, and each of the through hole S0 and the first holes S1 opens to each of the support surface 10a and the rear surface 10b. As Figure 2 shown, in a plan view, the through hole S0 is provided at the center of the support member 10. Further, the first holes S1 are provided in one-to-one correspondence with electrode protrusions 22 included in the electrode member 20 described below. In the drawings, the width of each of the first holes S1 is constant over the entire region along the length direction. Further, the cross-sectional shape of each of the first holes S1 is circular.

[0032] It should be noted that Figure 1 in the example shown, the shape of the support member 10 is circular in a plan view; however, the shape of the support member 10 is not limited thereto, and for example, it may be polygonal. The cross-sectional shape of each of the holes constituted by the through hole S0 and the first holes S1 is not limited to circular, and for example, it may be a polygon such as a square or a pentagon. The support member 10 may be provided or omitted as the case may be, or the support member 10 may be integrated with the electrode member 20.

[0033] Figure 1The electrode member 20 shown is a conductive member to be in contact with the surface of a living body. The electrode member 20 is made of an elastic material having conductivity. The elastic material includes a rubber material and conductive particles. Examples of the rubber material include silicone rubber, terpolymer rubber made of ethylene, propylene, and diene, nitrile rubber, and polyurethane rubber. Among the above rubbers, silicone rubber is suitable as the rubber material from the perspective of biocompatibility and the like. Examples of the conductive particles include carbon particles composed of carbon black, carbon nanotubes, or graphite, and metal particles composed of a metal such as silver or a metal compound such as silver chloride. It should be noted that the elastic material may include not only a rubber material and conductive particles, but also a fiber-based material (such as a non-woven fabric made of a resin material or a carbon material, etc.) or a woven fabric, or may include various additives.

[0034] The electrode member 20 includes a base portion 21 and an electrode protrusion portion 22. The base portion 21 and the electrode protrusion portion 22 are made of the same material, but may also be made of different materials respectively.

[0035] The base portion 21 is a part of the electrode member 20 that supports the electrode protrusion portion 22. In Figure 1 the example shown, the base portion 21 is disc-shaped, and in a plan view, the outer shape of the base portion 21 is substantially the same as the outer shape of the support member 10. The base portion 21 includes a mounting surface 21a and a surface 21b that faces a direction opposite to the direction in which the mounting surface 21a faces. The surface 21b that faces a direction opposite to the direction in which the mounting surface 21a faces is the surface that contacts the support surface 10a, and the surface 21b is bonded to the support surface 10a by vulcanization bonding or by an adhesive or the like. The mounting surface 21a is provided with the electrode protrusion portion 22.

[0036] As Figure 3 shown, the base portion 21 is provided with a plurality of second holes S2. The second holes S2 are holes that penetrate the support member 10 in the thickness direction, and the second holes S2 open toward each of the mounting surface 21a and the surface 21b that faces a direction opposite to the direction in which the mounting surface 21a faces. The second holes S2 are provided in one-to-one correspondence with the electrode protrusion portion 22. In the drawings, the width of each of the second holes S2 is constant over the entire region along the length direction. In addition, the cross-sectional shape of each of the second holes S2 is circular.

[0037] It should be noted that in Figure 1 the example shown, the shape of the base portion 21 is circular in a plan view; however, the shape of the base portion 21 is not limited thereto, and for example, it may be polygonal. In addition, the shape of the base portion 21 in a plan view may be different from the shape of the support member 10 in a plan view.

[0038] Figure 4 isFigure 3 An enlarged view of a part of the electrode protrusion 22 shown. As Figure 4 shown, each electrode protrusion in the electrode protrusions 22 is a protrusion protruding from the mounting surface 21a of the base 21. Each electrode protrusion in the electrode protrusions 22 is made of a single material of a conductive elastic material, and each electrode protrusion in the electrode protrusions 22 serves as an electrode configured to contact a detection object to detect a biometric signal. In addition, each electrode protrusion in the electrode protrusions 22 is hollow and has an internal space S. The internal space S communicates with the second hole S2 of the base 21 described above. Since each electrode protrusion in the electrode protrusions 22 is hollow, the number of conductive particles can be reduced compared with a solid protrusion. Therefore, the rigidity of each electrode protrusion in the electrode protrusions 22 can be reduced. Therefore, the possibility that the subject feels discomfort when wearing the bioelectrode 1 can be reduced. In particular, when wearing the bioelectrode 1 for a long time, it is less likely to feel discomfort. In addition, since the number of conductive particles can be reduced, the material cost can be reduced.

[0039] As Figure 2 shown, the electrode protrusions 22 are arranged in a circular manner on the mounting surface 21a. More specifically, when viewed in the thickness direction of the base 21, the electrode protrusions 22 are separated from each other at regular angular intervals on a virtual circle C1 centered on the center O of the mounting surface 21a.

[0040] Alternatively, the electrode protrusions 22 can be separated from each other at irregular angular intervals. In addition, a plurality of other electrode protrusions 22 can be provided, and the plurality of other electrode protrusions 22 are arranged on another circle concentric with the virtual circle C1. In addition, in Figure 2 the example shown, the number of the electrode protrusions 22 is nine; however, the number of the electrode protrusions 22 is not limited thereto, and it can be eight or less, or can be ten or more. However, from the perspective of achieving stable contact between the living body and the electrode member 20, the number of the electrode protrusions 22 is preferably three or more, and more preferably four or more.

[0041] As Figure 4As shown, each electrode protrusion 22 in the electrode protrusion portions includes a proximal end 22p and a distal end 22t. The proximal end 22p of each electrode protrusion 22 in the electrode protrusion portions is connected to the base 21. The distal end 22t of each electrode protrusion 22 in the electrode protrusion portions is to be in contact with the surface of a living body. Additionally, the circle connecting the proximal ends 22p of the corresponding electrode protrusions 22 to each other is the aforementioned virtual circle C1. Additionally, the circle connecting the centers Op of the distal ends 22t of the electrode protrusions 22 to each other is the virtual circle C2. The virtual circle C2 is arranged outside the virtual circle C1. It should be noted that the distal end 22t is not a plane, and the center Ot of the distal end 22t corresponds to the distal end 22t.

[0042] As Figure 2 shown, in each electrode protrusion 22 of the electrode protrusion portions, the center Ot of the distal end 22t is arranged to be more radially outward away from the center O of the mounting surface 21a than the center Op of the proximal end 22p. Additionally, as Figure 4 shown, the central axis O2 along the protruding direction of each electrode protrusion 22 in the electrode protrusion portions is inclined with respect to the normal line O1 passing through the center O of the mounting surface 21a. The normal line O1 overlaps with the center line of the base 21. This inclination causes the electrode protrusion 22 to deform flexibly such that when the biological electrode 1 is pressed against a subject, the distal end 22t first expands radially outward. Additionally, as described above, each electrode protrusion 22 in the electrode protrusion portions is hollow; thus, when each electrode protrusion 22 in the electrode protrusion portions deforms, each electrode protrusion 22 in the electrode protrusion portions deforms in a bending manner. Therefore, the contact area between each electrode protrusion 22 in the electrode protrusion portions and the subject can be increased. Therefore, a reduction in the measurement accuracy of the biological electrode 1 can be generally prevented.

[0043] The inclination angle of the central axis O2 with respect to the normal line O1 is not particularly limited; additionally, from the perspective of ensuring good contact between the living body and the electrode member 20, the inclination angle is preferably 10 degrees or greater than 10 degrees, more preferably 10 degrees or greater than 10 degrees and 45 degrees or less than 45 degrees, still more preferably 10 degrees or greater than 10 degrees and 30 degrees or less than 30 degrees. It should be noted that the inclination angles of the electrode protrusions 22 can be the same as or different from each other.

[0044] As Figure 4As shown, each electrode protrusion 22 in the electrode protrusion part includes a distal part 220, and the distal part 220 includes a distal end 22t and has a convex curve shape. In the example shown in the drawings, the shape of the distal part 220 is hemispherical. Since the shape of the distal part 220 of the electrode protrusion 22A is a convex curve, the possibility that the subject feels discomfort when wearing the biological electrode 1 can be reduced. It should be noted that the shape of the distal part 220 of each electrode protrusion 22 in the electrode protrusion part is a convex curve; however, the shape of the distal part 220 of each electrode protrusion 22 in the electrode protrusion part is not limited to this, and the shape can be freely selected.

[0045] In addition, each electrode protrusion 22 in the plurality of electrode protrusions 22 has a conical shape. Therefore, the width W of each electrode protrusion 22 in the electrode protrusion part gradually narrows from the proximal end 22p to the distal end 22t. Therefore, the width of the distal part 220 is smaller than the width of the proximal end 22p. Since the width W of each electrode protrusion 22 in the electrode protrusion part gradually narrows from the proximal end 22p to the distal end 22t, compared with the case where the width W is constant, when the electrode member 20 presses against the subject, the electrode protrusion 22 may deform and expand radially outward. Therefore, the contact area between each electrode protrusion 22 in the electrode protrusion part and the subject can be further increased. In addition, since the width W gradually narrows from the proximal end 22p to the distal end 22t, the rigidity of the proximal end 22p and its vicinity can be maintained. Therefore, deformation of the base of the electrode protrusion 22 can be generally prevented. Therefore, the biological electrode 1 can be stably worn on the measurement site of the subject; therefore, a change in the position of the measurement site can be generally prevented. It should be noted that the width W of the electrode protrusion 22 may be constant from the proximal end 22p to the distal end 22t.

[0046] As Figure 4 shown, in this embodiment, the thickness D between the inner wall surface and the outer wall surface of each electrode protrusion 22 in the electrode protrusion part is constant. Since the thickness D is constant, each electrode protrusion 22 in the electrode protrusion part can be easily produced compared with the case where the thickness D is not constant. In addition, the thickness D is not particularly limited; further, from the perspective of being easily deformed, the thickness D is preferably 0.2 mm or greater than 0.2 mm and 1.0 mm or less than 1.0 mm, and more preferably 0.4 mm or greater than 0.4 mm and 0.6 mm or less than 0.6 mm. It should be noted that the thickness D of the electrode protrusions 22 may be the same as or different from each other.

[0047] In addition, the distal portion 220 of each electrode protrusion 22 in the electrode protrusions 22 is not provided with a hole that allows the internal space S and the outside to communicate with each other. If the distal portion 220 is provided with a hole, the rigidity of the distal portion 220 will be reduced beyond the required rigidity. Therefore, when the distal portion 220 of each electrode protrusion 22 in the electrode protrusions 22 presses against the subject, the distal portion 220 may collapse. Therefore, it is highly likely that a portion of each electrode protrusion 22 in the electrode protrusions 22 located between the distal portion 220 and the proximal end 22p does not deform in a bending manner and only the distal portion 220 collapses. In this case, the contact area between each electrode protrusion 22 in the electrode protrusions 22 and the subject will not increase. On the contrary, since each electrode protrusion 22 in the electrode protrusions 22 according to the present embodiment is not provided with a hole, the electrode protrusion 22 may deform to expand radially outward; therefore, the contact area between each electrode protrusion 22 in the electrode protrusions 22 and the subject can be further increased.

[0048] In the present embodiment, the cross-sectional outer contour shape of each electrode protrusion 22 in the electrode protrusions 22 is circular. Therefore, compared with the case where the cross-sectional outer contour shape of each electrode protrusion 22 in the electrode protrusions 22 is quadrilateral, the possibility of the subject feeling discomfort can be reduced. In addition, the cross-sectional outer contour shape of each electrode protrusion 22 in the electrode protrusions 22 is not limited to a circle, and may be, for example, a polygon such as a square or a pentagon.

[0049] As Figure 4 shown, in the present embodiment, the generatrix B1 arranged on a part of each electrode protrusion 22 in the electrode protrusions 22 is parallel to the normal line O1, and this part of each electrode protrusion 22 in the electrode protrusions 22 is the farthest from the normal line O1. In addition, the generatrix B2 arranged on a part of each electrode protrusion 22 in the electrode protrusions 22 is inclined with respect to the normal line O1 such that the distance between the generatrix B2 and the normal line O1 gradually increases from the proximal end 22p to the distal end 22t, and this part of each electrode protrusion 22 in the electrode protrusions 22 is the closest to the normal line O1.

[0050] The height h of the electrode protrusion 22 is not particularly limited, and preferably is 6 mm or greater than 6 mm and 15 mm or less than 15 mm. The height h within this range enables the electrode protrusion 22 to appropriately contact the hairy surface of the living body. If the height h of the electrode protrusion 22 is too short, it may be difficult to maintain a good contact state between the electrode protrusion 22 and the hairy living body surface depending on the state of the subject's hair, etc. On the other hand, if the height h of the electrode protrusion 22 is too long, it is not desirable from the perspective of reducing the size of the biological electrode 1. In addition, when forming the electrode member 20 using a mold, the mold release property is often worse.

[0051] It should be noted that the height h of the electrode protrusion 22 is the length from the proximal end 22p to the distal end 22t of a part of the electrode protrusion 22 in the thickness direction of the base 21 (in other words, in the direction along the normal line O1 of the mounting surface 21a). Additionally, from the perspective of ensuring a good contact state between the living body and the electrode member 20, preferably, the height h of the electrode protrusion 22 is equal.

[0052] There is no particular limitation on the hardness of the material of each electrode protrusion in the electrode protrusion 22. In other words, there is no particular limitation on the hardness of the conductive material including the conductive particles and the rubber material. Additionally, from the perspective of being easily deformable, preferably, the hardness is measured to be 40 degrees or greater than 40 degrees and 80 degrees or less than 80 degrees using a durometer "Type A" according to JIS K 6253.

[0053] Figure 3 The shown connector 30 is a snap - type male connector and is connected by being fitted into a female connector electrically connected to the measuring device, although this is not shown. The connector 30 includes a first conductive member 31 and a second conductive member 32. Each of the first conductive member 31 and the second conductive member 32 is a cylindrical body with a bottom, and the cylindrical body has a flange, and is made of a metal material such as stainless steel, for example. Additionally, the first conductive member 31 and the second conductive member 32 cooperate with each other.

[0054] The first conductive member 31 includes a first cylindrical body having a bottom 311 and a first flange 312. The first cylindrical body having a bottom 311 generally has the shape of a cylindrical body with a bottom. The first cylindrical body having a bottom 311 includes an open end joined to the first flange 312. A part of the first cylindrical body having a bottom 311 is inserted into the through - hole S0 of the support member 10. The first flange 312 contacts the support surface 10a of the support member 10, and the first flange 312 has the shape of a flange extending radially outward from the open end of the first cylindrical body having a bottom 311.

[0055] The second conductive member 32 includes a second cylindrical body having a bottom 321 and a second flange 322. The second cylindrical body having the bottom 321 generally has the shape of a cylindrical body with a bottom. The second cylindrical body having the bottom 321 includes an open end coupled to the second flange 322. The inner diameter of the second cylindrical body having the bottom 321 is substantially equal to the outer diameter of the first cylindrical body having the bottom 311. The second cylindrical body having the bottom 321 is arranged to cover a part of the first cylindrical body having the bottom 311, and the first conductive member 31 and the second conductive member 32 cooperate with each other. The second flange 322 contacts the rear surface 10b of the support member 10, and the second flange 322 has the shape of a flange that extends radially outward from the open end of the second cylindrical body having the bottom 321. In a state where the first conductive member 31 and the second conductive member 32 cooperate with each other, the support member 10 is sandwiched between the first flange 312 and the second flange 322. Accordingly, the connector 30 is fixed to the support member 10.

[0056] As described above, in the biological electrode 1 according to the present embodiment, each of the electrode protrusions 22 is made of a single material including conductive particles and a rubber material, and each of the electrode protrusions 22 is solid; in addition, the central axis O2 of each of the electrode protrusions 22 is inclined with respect to the normal line O1 so as to extend radially. Accordingly, the rigidity of each of the electrode protrusions 22 can be reduced; thus, the possibility of discomfort when wearing the biological electrode 1 can be reduced. In addition, each of the electrode protrusions 22 flexibly bends so as to expand outward when wearing the biological electrode 1; thus, the contact area between each of the electrode protrusions 22 and the measurement site of the subject can be increased. Accordingly, a decrease in measurement accuracy can be generally prevented.

[0057] 2. Second Embodiment

[0058] Hereinafter, a second embodiment according to the present disclosure will be described. In the second embodiment, for elements having substantially the same effects and functions as those of the first embodiment, the reference numerals used in the description of the first embodiment are used, and the detailed description of these elements is appropriately omitted.

[0059] Figure 5 is a cross-sectional view showing a part of the electrode member 20A according to the second embodiment. As Figure 5 shown, the second embodiment is the same as the first embodiment except that the thickness between the inner wall surface and the outer wall surface of the electrode protrusion 22A (i.e., any one of the electrode protrusions 22A included in the electrode member 20A) is not constant.

[0060] As Figure 5As shown, the electrode protrusion 22A includes a distal portion 220A and a thin portion 221. The distal portion 220A includes a distal end 22t, and the distal portion 220A is a part of the electrode protrusion 22A having a convex curved shape. The thin portion 221 is a part of the electrode protrusion 22A disposed between the distal portion 220A and the mounting surface 21a, and the thickness D2 of this part of the electrode protrusion 22A is smaller than the thickness D1 of the distal portion 220A.

[0061] Since the thickness D1 of the distal portion 220A is greater than the thickness D2 of the thin portion 221, the strength of the distal portion 220A can be increased. Therefore, the electrode protrusion 22A (any one of the electrode protrusions in the electrode protrusion 22A) may not be deformed from the distal portion 220A, but may be deformed from a position near the middle of the electrode protrusion 22A in the protruding direction of the electrode protrusion 22A. In other words, collapse of the distal portion 220A can be substantially prevented, and each electrode protrusion in the electrode protrusion 22A can be easily deformed in a bending manner. Therefore, the contact area between each electrode protrusion in the electrode protrusion 22A and the subject can be increased. Therefore, the measurement accuracy can be improved.

[0062] The thickness D1 is not particularly limited; further, from the perspective of substantially preventing collapse of the distal portion 220A, the thickness D1 is preferably 1 mm or greater than 1 mm and 5 mm or less than 5 mm, more preferably 2 mm or greater than 2 mm and 3 mm or less than 3 mm. In addition, the thickness D2 is not particularly limited; further, from the perspective of easy deformation, the thickness D2 is preferably 0.2 mm or greater than 0.2 mm and 1.0 mm or less than 1.0 mm, more preferably 0.4 mm or greater than 0.4 mm and 0.6 mm or less than 0.6 mm. It should be noted that the thicknesses D1 of the electrode protrusions 22A may be the same as or different from each other, and the thicknesses D2 of the electrode protrusions 22A may be the same as or different from each other.

[0063] 3. Third Embodiment

[0064] Hereinafter, a third embodiment according to the present disclosure will be described. In the third embodiment, for elements having substantially the same effects and functions as those of the first embodiment, the reference numerals used in the description of the first embodiment are used, and the detailed description of these elements is appropriately omitted.

[0065] Figure 6 is a cross-sectional view showing a part of the electrode member 20B according to the third embodiment. As Figure 6 shown, the third embodiment is the same as the first embodiment except that the thickness between the inner wall surface and the outer wall surface of the electrode protrusion 22B (i.e., any one of the electrode protrusions 22B included in the electrode member 20B) is not constant.

[0066] As Figure 6 shown, the electrode protrusion 22B includes an inner portion 222 and an outer portion 223. The inner portion 222 is a section disposed inside a frustum that connects the virtual circles C1 and C2 shown above Figure 2 to each other. On the other hand, the outer portion 223 is a section disposed outside the frustum. It should be noted that the inner portion 222 can be referred to as a section disposed radially inwardly away from a virtual plane that connects the central axis O2 of the electrode protrusion 22B shown Figure 6 . The outer portion 223 can be referred to as a section disposed radially outwardly away from the virtual plane.

[0067] The thickness D4 of the outer portion 223 is smaller than the thickness D3 of the inner portion 222. Therefore, the rigidity of the outer portion 223 can be easily lower than the rigidity of the inner portion 222. Thus, in the present embodiment, compared with the first embodiment, when the electrode member 20B is pressed against the subject, the electrode protrusion 22B may deform to expand radially outward. Therefore, the contact area between each electrode protrusion in the electrode protrusion 22B and the subject can be further increased.

[0068] The thickness D3 is not particularly limited; in addition, from the perspective that the rigidity of the inner portion 222 is higher than the rigidity of the outer portion 223, the thickness D3 is preferably 1 mm or greater than 1 mm and 5 mm or less than 5 mm, more preferably 2 mm or greater than 2 mm and 3 mm or less than 3 mm. In addition, the thickness D4 is not particularly limited; in addition, from the perspective of easy deformation, the thickness D4 is preferably 0.2 mm or greater than 0.2 mm and 1.0 mm or less than 1.0 mm, more preferably 0.4 mm or greater than 0.4 mm and 0.6 mm or less than 0.6 mm. It should be noted that the thicknesses D3 of the electrode protrusions 22 may be the same as or different from each other, and the thicknesses D4 of the electrode protrusions 22 may be the same as or different from each other.

[0069] 4. Fourth Embodiment

[0070] Hereinafter, a fourth embodiment according to the present disclosure will be described. In the fourth embodiment, for elements whose effects and functions are substantially the same as those of the first embodiment, the reference numerals used in the description of the first embodiment are used, and the detailed description of these elements is appropriately omitted.

[0071] Figure 7 is a side view of the electrode member 20C according to the fourth embodiment. Figure 8 is Figure 7 the bottom view of the electrode member 20C shown Figure 9 is Figure 7Cross-sectional view of a part of the electrode protrusion 22C shown. As Figure 7 , Figure 8 and Figure 9 shown, except that a part of the electrode protrusion 22C (i.e., any one of the electrode protrusions 22C included in the electrode member 20C) is cut off, the fourth embodiment is the same as the first embodiment.

[0072] As Figure 7 and Figure 9 shown, the electrode protrusion 22C (any one of the electrode protrusions 22C) includes a distal portion 220 and an intermediate portion 225. The intermediate portion 225 is a part of the electrode protrusion 22C located between the distal portion 220 and the mounting surface 21a, and the electrode protrusion 22C is any one of the electrode protrusions 22C. The shape of the intermediate portion 225 is a split cylindrical shape obtained by cutting off the radially outer portion along the normal line O1 from the cylindrical body. In the example shown in the drawings, the cross-sectional shape of the intermediate portion 225 along the central axis O2 is an arc. In addition, in the present embodiment, the intermediate portion 225 is arranged radially inward away from the virtual circle C2.

[0073] In addition, from another perspective, an opening 224 is provided in a part of the side surface of the electrode protrusion 22C (any one of the electrode protrusions 22C), and this part of the side surface of the electrode protrusion 22C is separated from the distal end 22t. The opening 224 is provided radially outward so as not to face the normal line O1. The opening 224 is provided as a through hole communicating with the corresponding internal space S from the outer wall surface to the inner wall surface of the electrode protrusion 22.

[0074] Due to the provision of the opening 224, the rigidity of the intermediate portion 225 can be reduced. On the contrary, since the rigidity of the distal portion 220 is maintained, the rigidity of the distal portion 220 can be greater than the rigidity of the intermediate portion 225. Therefore, the electrode protrusion 22C (any one of the electrode protrusions 22C) may not be deformed from the distal portion 220, but may be deformed from the vicinity of the middle of the electrode protrusion 22C in the protruding direction of the electrode protrusion 22C. Therefore, the contact area between each electrode protrusion in the electrode protrusion 22C and the subject can be increased. Therefore, the measurement accuracy can be improved.

[0075] It should be noted that the opening area of the opening 224 is not particularly limited and can be freely selected. In addition, the opening areas of the electrode protrusions 22C can be the same as or different from each other.

[0076] In addition, portions of the base 21C and the side surface of the support member 10 corresponding to the opening 224 are cut away. Further, in this embodiment, the base 21C and the electrode projection portion 22C are integrally formed. Since the base 21C and the electrode projection portion 22C are integrally formed, the strength of the mold can be enhanced as compared with the case where the base 21C and the electrode projection portion 22C are separate from each other; thus, it is easy to produce the electrode member 20C having the required rigidity. Further, in this embodiment, as Figure 8 shown, a part of the distal end portion 220 of each electrode projection portion in the electrode projection portion 22C is arranged radially outward away from the base 21; however, when viewed in the direction along the normal line O1, the entire distal end portion 220 can overlap with the base 21.

[0077] 5. Variations

[0078] For example, the above-described embodiment can be modified as follows.

[0079] Figure 10 is a side view of the bioelectrode 1D according to the variation. As Figure 10 shown, in the electrode member 20D of the bioelectrode 1D, the bus bar B1 arranged on a part of each electrode projection portion in the electrode projection portion 22D is inclined with respect to the normal line O1 such that the distance between the bus bar B1 and the normal line O1 gradually increases from the proximal end 22p to the distal end 22t, and this part of each electrode projection portion in the electrode projection portion 22D is the farthest from the normal line O1. Similarly, the bus bar B2 arranged on a part of each electrode projection portion in the electrode projection portion 22D is inclined with respect to the normal line O1 such that the distance between the bus bar B2 and the normal line O1 gradually increases from the proximal end 22p to the distal end 22t, and this part of each electrode projection portion in the electrode projection portion 22D is the closest to the normal line O1.

[0080] According to such a bioelectrode 1D, similar to the corresponding embodiment, each electrode projection portion in the electrode projection portion 22D flexibly bends to expand outward when the bioelectrode 1D is worn; thus, it is possible to increase the contact area between each electrode projection portion in the electrode projection portion 22D and the measurement site of the subject.

[0081] The present disclosure is described based on the preferred embodiments and variations; however, the present disclosure is not limited to the above-described embodiments. Further, the configuration of each element of the present disclosure can be replaced with a freely selectable configuration that provides the same function as that provided by the above-described embodiments, and freely selectable elements can be added to the freely selectable configuration.

[0082] In addition, corresponding embodiments can be appropriately combined. For example, the electrode protrusion 22A according to the second embodiment and the electrode protrusion 22B according to the third embodiment can be included. In this case, for example, the thickness D1 of the distal portion 220A, the thickness D3 of the inner portion 222, and the thickness D4 of the outer portion 223 can decrease in sequence. In addition, for example, the electrode protrusion 22A according to the second embodiment and the electrode protrusion 22C according to the fourth embodiment can be included.

[0083] Description of Reference Numerals

[0084] 1. Bioelectrode, 1D. Bioelectrode, 10. Support member, 10a. Support surface, 10b. Rear surface, 20. Electrode member, 20A. Electrode member, 20B. Electrode member, 20C. Electrode member, 20D. Electrode member, 21. Base, 21C. Base, 21a. Mounting surface, 21b. Surface, 22. Electrode protrusion, 22A. Electrode protrusion, 22B. Electrode protrusion, 22C. Electrode protrusion, 22D. Electrode protrusion, 22p. Proximal end, 22t. Distal end, 30. Connector, 31. First conductive member, 32. Second conductive member, 220. Distal portion, 220A. Distal portion, 221. Thin portion, 222. Inner portion, 223. Outer portion, 224. Opening, 225. Intermediate portion, 311. First cylindrical body with a bottom, 312. First flange, 321. Second cylindrical body with a bottom, 322. Second flange, B1. Generatrix, B2. Generatrix, C1. Virtual circle, C2. Virtual circle, D. Thickness, D1. Thickness, D2. Thickness, D3. Thickness, D4. Thickness, O. Center, O1. Normal line, O2. Central axis, Op. Center, Ot. Center, S. Inner space, S0. Through hole, S1. First hole, S2. Second hole, h. Height.

Claims

1. A biological electrode, comprising: a base, the base comprising a mounting surface; and a plurality of electrode protrusions protruding from the mounting surface and comprising conductive particles and a rubber material, the plurality of electrode protrusions being configured to contact a detection object to detect a biometric signal, wherein the plurality of electrode protrusions are arranged in a circular manner on the mounting surface, wherein a central axis of each of the plurality of electrode protrusions is inclined with respect to a normal line passing through the center of the mounting surface, wherein a center of a distal end of each of the plurality of electrode protrusions is arranged to be more radially outwardly away from the center of the mounting surface than a center of a corresponding proximal end, and wherein each of the plurality of electrode protrusions is hollow.

2. The biological electrode according to claim 1, wherein a width of each of the plurality of electrode protrusions gradually narrows from the proximal end to the distal end.

3. The biological electrode according to claim 1 or 2, wherein each of the plurality of electrode protrusions includes a distal portion, the distal portion including the distal end and having a shape of a convex curve.

4. The biological electrode according to claim 1, wherein each of the plurality of electrode protrusions includes: a distal portion, the distal portion including the distal end; and a thin portion provided between the distal portion and the mounting surface, a thickness of the thin portion being less than a thickness between an inner wall surface and an outer wall surface of the distal portion.

5. The biological electrode according to claim 1, wherein each of the plurality of electrode protrusions includes: an inner portion; and an outer portion, the outer portion being more radially outwardly away from the center of the mounting surface than the inner portion, a thickness of the outer portion being less than a thickness between an inner wall surface and an outer wall surface of the inner portion.

6. The biological electrode according to claim 1, wherein one side of each of the plurality of electrode protrusions includes an opening separated from the distal end, and wherein the opening is arranged radially outwardly away from the center of the mounting surface.

7. A biological electrode, comprising: a base, the base comprising a mounting surface; and a plurality of electrode protrusions protruding from the mounting surface and comprising conductive particles and a rubber material, the plurality of electrode protrusions being configured to contact a detection object to detect a biometric signal, wherein the plurality of electrode protrusions are arranged in a circular manner on the mounting surface, wherein a central axis of each of the plurality of electrode protrusions is inclined with respect to a normal line passing through the center of the mounting surface, wherein a center of a distal end of each of the plurality of electrode protrusions is arranged to be more radially outwardly away from the center of the mounting surface than the center of the mounting surface, and wherein each of the plurality of electrode protrusions includes: a hemispherical distal portion, the hemispherical distal portion including the distal end; and An intermediate portion, the intermediate portion being disposed between the distal portion and the mounting surface and having a split cylindrical shape, the intermediate portion opening radially outwardly away from the center of the mounting surface.

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