Wearable devices

Abstract

To provide a wearable device with excellent wearability and measurement stability. [Solution] The wearable device of the present invention comprises clothing, a sheet electrode provided on the clothing containing conductive fibers and a conductive elastomer, and an array structure having a plurality of through holes formed on the biological contact surface of the sheet electrode.

Description

Technical Field

[0001] The present invention relates to wearable devices.

Background Art

[0002] Various developments have been made on wearable devices so far. As this type of technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes that holes are formed at the positions of the eyes and nose when a bioelectric stimulation device is attached to the face. Although not a wearable device, Patent Document 2 describes that a plurality of holes penetrating an insulating layer and a conductive layer are provided in a current collector used for an electrode sheet used in a battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as a result of the study by the present inventors, it has been found that there is room for improvement in terms of wearability in the bioelectric stimulation device as described in Patent Document 1 above.

Means for Solving the Problems

[0005] As a result of further study, the present inventors have found that by forming a plurality of through holes in the biological contact surface of the sheet electrode, it is possible to improve the measurement stability while suppressing a decrease in wearability, and have completed the present invention.

[0006] According to one aspect of the present invention, the following wearable device is provided. 1. Clothing and, A sheet electrode comprising conductive fibers and a conductive elastomer is provided on the garment, The sheet electrode has an array structure with multiple through holes formed on its biological contact surface, Equipped with, Wearable devices. 2. A wearable device as described in 1., The sheet electrode is a wearable device having an impregnation layer in which at least a portion of the conductive elastomer is impregnated into the layer of conductive fibers. 3. A wearable device as described in 1. or 2., The sheet electrode has a structure in which the conductive fiber layer and the conductive elastomer layer are laminated in this order. Having any of (i) and (iii), (i) and (iv), (ii) and (iii), or (ii) and (iv), (i) A structure in which the conductive elastomer does not cover the entire inner surface of the conductive fiber layer within the through hole. (ii) A structure in which the conductive elastomer covers at least a portion of the inner surface of the conductive fiber layer within the through hole. (iii) A structure in which the conductive elastomer does not cover the entire outer surface of the conductive fiber layer. (iv) A structure in which the conductive elastomer covers at least a portion of the outer surface of the layer of conductive fibers. Wearable devices. 4. A wearable device described in any one of items 1 to 3, A wearable device comprising a lead wire made of the conductive elastomer, which is electrically connected to the sheet electrode. 5. A wearable device described in any one of items 1 to 4, A wearable device in which the garment has other through holes that communicate with one of the plurality of through holes formed in the sheet electrode. 6. The wearable device according to any one of 1. to 5., where the clothing and the sheet electrode are fixed to each other by one or more fixing means selected from the group consisting of sewing, an adhesive material, and a thermocompression bonding material. 7. The wearable device according to any one of 1. to 6., where there is a margin at least in part around the arrangement structure on the living body contact surface of the sheet electrode, and the minimum distance between the end of the arrangement structure and the end of the sheet electrode is 0.1 mm or more. 8. The wearable device according to any one of 1. to 7., where the clothing is a belt.

Advantages of the Invention

[0007] According to the present invention, a wearable device excellent in wearing comfort and measurement stability is provided.

Brief Description of the Drawings

[0008] [Figure 1] It is a top view schematically showing an example of the configuration of the wearable device according to the present embodiment. [Figure 2] It is a cross-sectional view taken along the line I-I of FIG. 1. [Figure 3] It is an enlarged view in the α region of FIG. 2.

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description will be appropriately omitted. Also, the drawings are schematic and do not match the actual dimensional ratios.

[0010] The wearable device of the present embodiment will be described.

[0011] FIG. 1 schematically shows a top view of an example of the configuration of the wearable device 100 according to the present embodiment, FIG. 2 shows a cross-sectional view taken along the line I-I of the wearable device 100 in FIG. 1, and FIG. 3 shows an enlarged view of the α region of the wearable device 100 in FIG. 2.

[0012] The wearable device 100 according to the present embodiment includes clothing (e.g., belt 10), a sheet electrode 50 provided on the clothing and including conductive fibers 20 and a conductive elastomer 30, and an array structure 70 having a plurality of through-holes 60 formed in the biological contact surface 52 of the sheet electrode 50.

[0013] The wearable device 100 is worn on the body of a subject and can measure the bioelectric potential of the subject. When worn on the body, a state in which the biological contact surface 52 of the sheet electrode 50 contacts at least a part of the surface of the subject's body is maintained. By contacting the biological contact surface 52 with the surface of the body, the bioelectric potential can be detected.

[0014] The bioelectric potential is not particularly limited, and examples include an electrocardiogram, a muscle-skin potential, an electroencephalogram, and the like.

[0015] According to the study by the present inventors, when the formation pattern of the conductive elastomer 30 has a sheet-like structure in which a plurality of mutually independent through-holes 60 are formed, it has been found that the measurement stability such as an electrocardiogram can be improved as compared with the case where a line-and-space shape in which a plurality of separated linear patterns are arranged.

[0016] In addition, according to the findings of the present inventors, it has been found that if the state in which the biological contact surface 52 of the sheet electrode 50 continues to contact the surface of the subject's skin or the like, the wearing comfort may decrease due to stuffiness.

[0017] Based on such findings, as a result of further study, it has been found that by forming a plurality of through-holes 60 in the biological contact surface 52 of the sheet electrode 50, a decrease in wearing comfort can be suppressed.

[0018] In this specification, wearability can be indicated by the degree of discomfort or other factors related to the wearing experience. Furthermore, the degree of variation in skin condition on the contact surface, such as redness, may be substituted or added to the indicator of wearability.

[0019] Clothing is not particularly limited as long as it can be worn by the human subject, but examples include belts 10 and garments. Among these, clothing that is attached to the body by applying pressure or tightening is preferred, such as belts 10 and compression wear. According to this embodiment, even when the garment is fitted with pressure or tightened, stuffiness on the contact surface can be suppressed, and a decrease in wearability can be prevented.

[0020] The belt 10 may be made of an elastic material. Examples of the material include, but are not limited to, insulating fiber materials. The elasticity of the material is preferably 50% or more.

[0021] The belt 10 is attached to the subject's body by known means, such as wrapping it around the torso, arms, legs, or neck. As an example of attachment, the belt 10 can be attached to the torso between the chest and abdomen.

[0022] The belt 10 (clothing) and the sheet electrode 50 may be fixed to each other by one or more fixing means selected from the group consisting of sewing, adhesive materials, and heat-sealing materials, but are not limited to this.

[0023] As shown in Figure 1, the sheet electrode 50 is provided on at least a portion of the surface of the belt 10. The number of sheet electrodes 50 on the belt 10 may be one, or two or more, depending on the application.

[0024] The sheet electrode 50 may be provided with lead wiring 80, as shown in Figure 1. The lead wiring 80 functions as an external connection for electrically connecting to another electrical device. However, it is not limited to this, and the external connection may be formed directly on the sheet electrode 50.

[0025] The sheet electrode 50 includes conductive fibers 20 and a conductive elastomer 30, and it is preferable that a layer of conductive elastomer 30 is formed on at least the outermost layer of the sheet electrode 50. By including conductive fibers 20, the conductivity stability of the sheet electrode 50 when stretched can be improved compared to when conductive elastomer 30 is used alone.

[0026] The sheet electrode 50 may have a structure in which a layer of conductive fiber 20 and a layer of conductive elastomer 30 are laminated in this order, as shown in Figure 2. In this laminated structure, when viewed in cross-sectional view in the thickness direction of the sheet electrode 50, a layer of conductive fibers 20 may be present on part or all of the underside of the layer of conductive elastomer 30. Furthermore, in the laminated structure, it is preferable that the interface between the conductive fiber layer 20 and the conductive elastomer layer 30 exists between them. Furthermore, the thicknesses of the conductive fiber layer 20 and the conductive elastomer layer 30 may be different from or the same. Here, as shown in Figure 3, in a cross-sectional view of the sheet electrode 50 in the stacking direction, the thickness of the conductive fiber 20 layer is defined as T1, and the thickness of the conductive elastomer 30 is defined as T2. If the sheet electrode 50 includes an impregnation layer 54, the thickness of the impregnation layer 54 is defined to be included in T2, not T1. The sheet electrode 50 may be configured to satisfy 0.01 ≤ T2 / T1 ≤ 100. The lower limit of the T2 / T1 ratio is, for example, 0.01 or higher, preferably 0.05 or higher, and more preferably 0.1 or higher. This improves electrocardiogram measurement. The upper limit of T2 / T1 is, for example, 100 or less, preferably 50 or less, and more preferably 10 or less. The thickness T2 of the conductive elastomer 30 may be, for example, 0.1 to 1 mm.

[0027] In a top view (hereinafter sometimes abbreviated as top view) of the biological contact surface 52 of the sheet electrode 50 viewed from a vertical direction, part or all of the layer of conductive fibers 20 may be arranged inside the layer of conductive elastomer 30.

[0028] Furthermore, as shown in Figure 3, the sheet electrode 50 may have an impregnation layer 54 in which at least a portion of the conductive elastomer 30 is impregnated into the layer of conductive fibers 20. The impregnation layer 54 can suppress the peeling of the conductive elastomer 30 from the conductive fibers 20 even when the belt 10 is deformed or stretched.

[0029] One method for forming the impregnation layer 54 is to apply a conductive paste to the layer of conductive fibers 20 and heat it. When the conductive paste is applied, at least a portion of it impregnates the layer of conductive fibers 20. Then, heating removes the solvent in the conductive paste, and if necessary, the elastomer components crosslink to form the conductive elastomer 30. The composition of the conductive paste will be described later.

[0030] The through-holes 60 are holes that penetrate both the front and back surfaces of the sheet electrode 50 and are formed in the region of the bio-contact surface 52, as shown in Figure 1. In other words, when the sheet electrode 50 comes into contact with the surface of the subject, the multiple through-holes 60 can form non-contact regions on the bio-contact surface 52. When viewed from the vertical direction of the surface of the conductive elastomer 30 layer, the conductive elastomer 30 layer may be formed around the entire periphery of each of the multiple through-holes 60.

[0031] Here, as shown in Figure 1, when viewed from the vertical direction of the surface of the conductive elastomer 30 layer, the area surrounded by the outer edge of the conductive elastomer 30 layer is A1 (however, including the region in which the through holes 60 are formed), and the total area of ​​the multiple through holes 60 is A2. In this case, the sheet electrode 50 may be configured such that 10% ≤ [(A1 - A2) / A1)] × 100 < 100%. The lower limit of [(A1-A2) / A1)]×100 may be 10% or more, 30% or more, or 60% or more. Furthermore, the upper limit of [(A1-A2) / A1)]×100 may be less than 100%, 98% or less, or 95% or less. By keeping the total area of ​​the through-holes within an appropriate range, the accuracy of measurement and ease of installation can be further improved.

[0032] The widths of the individual holes in the multiple through holes 60 may be the same or different from each other, but it is preferable that they be the same. The maximum width inside the through hole 60 may be, for example, 0.1 mm to 10 mm. The number of through holes 60 arranged in the array structure 70 is, for example, 0.1 holes / cm, depending on the width of the holes. 2 ~2500 pieces / cm 2 That is also acceptable. In this specification, "~" indicates that the upper and lower limits are included unless otherwise specified.

[0033] The shape of the through-hole 60 in the top view of the sheet electrode 50 is not particularly limited, but may be elliptical, circular, polygonal, or irregular in shape, with elliptical or circular being preferred.

[0034] The through-hole 60 penetrates the layer of conductive fibers 20 and the layer of conductive elastomer 30 contained in the sheet electrode 50. In other words, the sheet electrode 50 may have any of the following structures: a structure having (i) and (iii), a structure having (i) and (iv), a structure having (ii) and (iii), or a structure having (ii) and (iv), as shown in Figure 3. (i) A structure in which the entire surface surface 22 of the conductive fiber layer 20 within the through hole 60 is not covered with conductive elastomer 30. (ii) A structure in which the conductive elastomer 30 covers at least a portion of the inner surface 22 of the layer of conductive fibers 20 within the through hole 60. (iii) A structure in which the entire outer surface 24 of the layer of conductive fibers 20 is not covered with conductive elastomer 30. (iv) A structure in which a conductive elastomer 30 covers at least a portion of the outer surface 24 of the layer of conductive fibers 20.

[0035] Here, by applying the conductive paste to the layer of conductive fibers 20 and then performing a drilling process that penetrates the layer of conductive elastomer 30 and the layer of conductive fibers 20, a structure is obtained in which the conductive elastomer 30 does not cover the inner surface 22 of the layer of conductive fibers 20 within the through hole 60. Alternatively, by drilling the layer of conductive fibers 20 first and then applying the conductive paste to the layer of conductive fibers 20, a structure is obtained in which the conductive elastomer 30 covers at least a portion of the inner surface 22 of the layer of conductive fibers 20 within the through hole 60. If the outer shape of the conductive fiber layer 20 is formed by cutting or other methods after the conductive paste has been applied, a structure is obtained in which the entire outer surface 24 of the conductive fiber layer 20 is not covered with conductive elastomer 30. If the conductive paste is applied after the outer shape of the conductive fiber layer 20 has been formed, a structure is obtained in which at least a portion of the outer surface 24 of the conductive fiber layer 20 is covered with conductive elastomer 30.

[0036] When the garment is a belt 10, it is preferable that the bio-contact surface 52 of the sheet electrode 50 in a top view has a margin (an area where the through-holes 60 are not formed) around at least a portion of the arrangement structure 70, as shown in Figure 1. The lower limit of the minimum distance D between the edge of the array structure 70 and the edge of the sheet electrode 50 is, for example, 0.1 mm or more, preferably 1 mm or more. This increases the mechanical strength of the sheet electrode 50 when it is deformed. On the other hand, the upper limit of the minimum distance D is not particularly limited, but it may be 10 mm or less.

[0037] The belt 10 may have other through holes that communicate with one of the multiple through holes 60 formed in the sheet electrode 50. The other through holes may be one or more. Each of the multiple other through holes communicates with another through hole 60. This further suppresses moisture buildup at the contact surface.

[0038] The conductive fiber 20 is a textile fabric composed of yarn containing conductive fibers, and may be woven or knitted. A conductive fiber may be obtained by adding a conductive substance to a non-conductive fiber. Examples of conductive materials include metals such as silver, copper, stainless steel, nickel, and aluminum, as well as nonmetals such as carbon and conductive polymers. These may be used individually or in combination of two or more. The ratio of metal to non-conductive fibers may be, for example, 10% by mass or more, 20% by mass or more, or 30% by mass or more. The non-conductive fiber material may be, for example, natural fibers such as cellulose or raw silk, or synthetic fibers such as nylon.

[0039] The addition of conductive material to non-conductive fibers may be done by, for example, wet coating treatment such as electroless metal plating, vapor deposition, sputtering, adhesion of metal foil, impregnation using copper sulfide, etc.

[0040] Furthermore, the conductive fiber 20 does not need to contain non-conductive fibers, as long as it is conductive. Alternatively, the conductive fiber 20 may be formed by knitting a conductive composite yarn. The conductive composite yarn is formed by using an elastic fiber as a core and wrapping a double layer of conductive fibers around it. That is, the conductive composite yarn is formed from a double-covered yarn or the like.

[0041] An example of the conductive elastomer 30 preferably includes an elastomer and a conductive filler. It is not limited to this, but also includes known additives. Examples of elastomers that can be used include silicone rubber, urethane rubber, fluororubber, nitrile rubber, acrylic rubber, styrene rubber, chloroprene rubber, and ethylene propylene rubber. Among these, silicone rubber is preferred as the rubber component. Specifically, conductive silicone rubber containing silicone rubber and conductive fillers is preferred for conductive elastomer 30. Conductive elastomer 30 may also contain non-conductive fillers such as silica in addition to conductive fillers such as silver powder.

[0042] An example of a conductive paste includes a conductive filler, an elastomer composition, and a solvent. The above-mentioned elastomer composition is an elastomer or a composition containing components for forming an elastomer, and an uncured thermosetting elastomer composition is preferred, with a silicone rubber-based curable composition described later being more preferred. Preferred solvents include aliphatic hydrocarbons, aromatic hydrocarbons, ethers, haloalkanes, carboxylic acid amides, sulfoxides, and the like. The content of conductive filler in the conductive paste is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, based on the total solid content of the paste. Furthermore, the content of conductive filler in the paste is preferably 90% by mass or less, more preferably 88% by mass or less, and even more preferably 85% by mass or less, based on the total solid content of the paste.

[0043] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., within the scope that can achieve the objectives of the present invention are included in the present invention. [Examples]

[0044] The present invention will be described in detail below with reference to examples, but the present invention is not limited in any way to the descriptions of these examples.

[0045] <Manufacturing of conductive paste> The obtained 15.3 parts by weight of silicone rubber-based curable composition was mixed in 34.8 parts by weight of decane (solvent), and 65.2 parts by weight of silver powder was added and mixed further to obtain a conductive paste with a total content of 69.8% by weight of silicone rubber-based curable composition and silver powder.

[0046] <Manufacturing of belt-type wearable devices> (Example 1) A belt base material was prepared comprising an insulating fiber fabric layer with elasticity and a conductive fiber fabric layer formed so as to have no steps on the surface of the insulating fiber fabric layer. Here, the conductive fiber fabric layer was made solely of conductive yarn (silver-plated conductive fiber, AGposs®, manufactured by Mitsufuji Co., Ltd.). Next, a 7cm x 7cm x 0.4mm thick belt substrate was placed on the flat surface of a SUS substrate, and then a mask (made of polyethylene terephthalate) with one 5cm x 5cm opening and a thickness of 125μm was placed on the surface of the conductive fiber fabric layer of the belt substrate. Next, the conductive paste described above was applied to the opening of the mask, and squeegee printing was performed multiple times using a glass plate. Next, the mask was removed, and the printed conductive paste 1 was dried at 140°C for 20 minutes and cured at 180°C for 2 hours to form a conductive elastomer layer on the conductive fiber fabric layer of the belt substrate. Next, multiple through-holes were formed that penetrated the conductive fiber fabric layer and the conductive elastomer layer, forming a sheet electrode. When viewed from the vertical direction of the surface of the conductive elastomer layer, the conductive elastomer layer was formed all around each of the multiple through-holes. Subsequently, the sheet electrodes were attached to a belt substrate to create a belt-type wearable device.

[0047] (Comparative Example 1) A belt-type wearable device was fabricated in the same manner as in Example 1, except that through-holes were not formed. (Comparative Example 2) A belt-type wearable device was fabricated in the same manner as in Example 1, except that the conductive paste was applied so that the line-and-space L / S ratio was 5 mm:5 mm, and linear coatings and linear grooves were formed alternately, without forming the through holes.

[0048] In the wearable device of Example 1, the thickness of the conductive fiber fabric layer was 0.6 mm, and the thickness of the conductive elastomer layer was 0.4 mm. For the wearable device of Example 1, when viewed from the vertical direction of the surface of the conductive elastomer layer, if the area surrounded by the outer edge of the conductive elastomer layer is A1 (however, including the area in which through holes are formed) and the total area of ​​the multiple through holes is A2, then [(A1-A2) / A1)] × 100 was 90%. For the wearable device of Example 1, the maximum width within the through-hole is 3 mm, and the number of through-holes is 1.4 per unit area of ​​the conductive elastomer layer / cm². 2 That was the case.

[0049] The following items were evaluated for the obtained wearable devices.

[0050] <Evaluation of wearability> The following wear tests were conducted using the wearable devices of Example 1 and Comparative Example 1. (Practical wear test) • Wearing time: 8 hours / day • Duration: 4 weeks Observation: Day 0, Week 1, Week 2, Week 4 • Number of subjects: 15 The condition of the skin in contact with each of the following materials was examined and compared. After four weeks, the wearable device in Comparative Example 1 showed a stronger tendency towards a stronger contact response than the device in Example 1.

[0051] <Skin irritation test> In the wearable devices of Example 1 and Comparative Examples 1-2, skin irritation was evaluated using the patch test evaluation method by microscopic observation (Kawa method) compiled by the Japan Industrial Skin Hygiene Association. When the skin irritation index was lower compared to Comparative Example 1, a lower index was considered to indicate good wearability. Example 1 and Comparative Example 2 showed favorable results.

[0052] <Evaluation of measurement stability> In the resulting wearable device, an external connector (a metal male snap button) was attached to the other side of the flexible substrate opposite to the side where the conductive elastomer layer was formed. The external connector and the conductive elastomer layer were then electrically connected to obtain three wearable bioelectrodes. An electrocardiogram measurement device was fabricated by connecting the external connection points of three wearable bioelectrodes to a BITalino (manufactured by Plux) via electrode cables with connectors (female snap buttons) and ECG sensors (manufactured by Plux). A wearable device equipped with three wearable bioelectrodes was directly attached to the subject's chest, and the subject's electrocardiogram was measured using a three-lead method (measurement point, reference, and body ground). As a result of the above findings, it was confirmed that the wearable device of Example 1 could monitor the electrocardiogram waveform while wearing it, walking, and jogging. However, in Comparative Example 2, it was found that significant noise occurred in the electrocardiogram waveform, especially when jogging.

[0053] Based on the above results, it was found that the wearable device of Example 1 has superior wearability compared to Comparative Example 1 and superior measurement stability compared to Comparative Example 2. [Explanation of symbols]

[0054] 10 belts 20 Conductive Fibers 22 Inner self 24 Outer surface 30 Conductive elastomer 50 sheet electrodes 52 Biological contact surface 54 Impregnated layer 60 Through holes 62 Interior wall surface 70 Sequence Structure 80 Outlet wiring 100 Wearable Devices D Minimum distance

Claims

1. Clothing and, A sheet electrode comprising conductive fibers and a conductive elastomer is provided on the garment, The sheet electrode has an array structure with multiple through holes formed on its biological contact surface, Equipped with, Wearable devices.

2. A wearable device according to claim 1, The sheet electrode is a wearable device having an impregnation layer in which at least a portion of the conductive elastomer is impregnated into the layer of conductive fibers.

3. A wearable device according to claim 1 or 2, The sheet electrode has a structure in which the conductive fiber layer and the conductive elastomer layer are laminated in this order. Having any of (i) and (iii), (i) and (iv), (ii) and (iii), or (ii) and (iv), (i) A structure in which the entire surface of the inner surface of the conductive fiber layer within the through hole is not covered with the conductive elastomer. (ii) A structure in which the conductive elastomer covers at least a portion of the inner surface of the layer of conductive fibers within the through hole. (iii) A structure in which the conductive elastomer does not cover the entire outer surface of the layer of conductive fibers. (iv) A structure in which the conductive elastomer covers at least a portion of the outer surface of the layer of conductive fibers. Wearable devices.

4. A wearable device according to claim 1 or 2, A wearable device comprising a lead wire made of the conductive elastomer, which is electrically connected to the sheet electrode.

5. A wearable device according to claim 1 or 2, A wearable device in which the garment has other through holes that communicate with one of the plurality of through holes formed in the sheet electrode.

6. A wearable device according to claim 1 or 2, A wearable device in which the clothing and the sheet electrode are fixed to each other by one or more fixing means selected from the group consisting of sewing, adhesive materials, and heat-sealing materials.

7. A wearable device according to claim 1 or 2, The biological contact surface of the sheet electrode has a margin around at least a portion of the arrangement structure. A wearable device in which the minimum distance between the end of the array structure and the end of the sheet electrode is 0.1 mm or more.

8. A wearable device according to claim 1 or 2, A wearable device in which the aforementioned garment is a belt.

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