JP6470049B2 - Yarn-like strain sensor element and fabric-like strain sensor element - Google Patents

Description

  The present invention relates to a thread-like strain sensor element and a fabric-like strain sensor element.

  In recent years, applications of strain sensor elements that detect expansion and contraction have expanded as sensors for robots and wearable devices, for example. Along with this, the needs for strain sensor elements are diversifying. In particular, there is a need for a strain sensor element that is thin and can detect relatively large expansion and contraction.

  As a thread-like strain sensor element, a conductive wire is spirally wound around a thread-like stretchable elastic body, and an inductance or capacitance between the conductive wires whose winding pitch changes as the elastic body stretches. A strain sensor element that detects expansion and contraction strain by measurement is proposed (see Japanese Patent Application Laid-Open No. 2011-089923).

  In the strain sensor element described in the above publication, accurate strain cannot be detected unless the winding pitch of the conductive wires is constant. For this reason, the publication discloses that the auxiliary member is wound in a spiral shape in the direction opposite to the conductive line from above the conductive line in order to fix the conductive line. However, when the auxiliary member is wound in this way, it is difficult to greatly expand and contract the elastic body in the longitudinal direction. Therefore, in the strain sensor element described in the above publication, there is a trade-off between detection accuracy and detectable strain magnitude.

JP 2011-089923 A

  In view of the above inconveniences, an object of the present invention is to provide a highly accurate yarn-like strain sensor element and fabric-like strain sensor element capable of detecting a relatively large stretching strain.

  The invention made in order to solve the above-mentioned problems is mainly composed of a core material including a plurality of carbon nanotubes aligned in one direction, a peripheral surface of the core material, and a synthetic resin or rubber having elasticity. A yarn-like strain sensor element comprising a protective layer.

  When the core material including a plurality of carbon nanotubes that are aligned in one direction is elongated, the plurality of carbon nanotubes are separated from each other according to a change in the length of the core material to increase the electrical resistance. By measuring this electrical resistance, stretch distortion can be detected. In addition, since the thread-like strain sensor element has a stretchable protective layer covering the peripheral surface of the core material, the contact relationship between the plurality of carbon nanotubes is maintained even after repeated stretches, so The detection accuracy of expansion / contraction strain is ensured without obstruction. Therefore, the thread-like strain sensor element can detect a relatively large stretching strain with high accuracy.

  It is preferable to further include a node forming member that is disposed on the outer peripheral surface of the protective layer and partially restricts expansion and contraction of the protective layer. Thus, by further providing a node forming member that is disposed on the outer peripheral surface of the protective layer and partially restricts expansion and contraction of the protective layer, the separation of the carbon nanotubes due to the elongation of the core material is partially promoted, The detection sensitivity can be further improved by increasing the linearity of the resistivity change.

  The node forming member may be a linear body or a belt-like body that is spirally wound around the outer peripheral surface of the protective layer. As described above, when the node forming member is a linear body or a belt-like body that is spirally wound around the outer peripheral surface of the protective layer, the partial separation of the carbon nanotubes is efficiently promoted to further improve the detection sensitivity. be able to.

  The node forming member may be conductive. As described above, since the node forming member has conductivity, the node forming member can be used as an electric circuit from one end vicinity of the core material to the other end vicinity, and the resistance value of the filamentous strain sensor element is detected. Wiring for this is facilitated.

  An elastomer layer that covers the outer peripheral surface of the protective layer may be further provided. Thus, by further providing an elastomer layer that covers the outer peripheral surface of the protective layer, the detection accuracy can be further improved by protecting the core body and the protective layer and stabilizing the expansion / contraction rate with respect to the tension.

  Another invention made to solve the above problem is a strain sensor element formed by knitting or weaving the thread-like strain sensor element.

  Since the cloth-like strain sensor element includes the thread-like strain sensor element as a thread constituting the cloth, a strain detecting function can be added by using the cloth-like strain sensor element as a cloth such as clothes. In addition, the fabric-like strain sensor element is formed by knitting or weaving the thread-like strain sensor element, so that other fibers partially suppress the expansion and contraction of the thread-like strain sensor element. Since the separation is partially promoted, it has high linearity and excellent detection sensitivity.

  Here, “aligned in one direction” does not require until the alignment directions are completely matched, and is a state having a random variation in the alignment direction and a regular deflection such as a so-called twist. Including.

  The yarn-like strain sensor element and the fabric-like strain sensor element of the present invention can detect a relatively large stretching strain and have high detection accuracy.

It is typical radial direction sectional drawing of the thread-like distortion sensor element of one Embodiment of this invention. FIG. 2 is a schematic plan view of a fabric-like strain sensor element using the yarn-like strain sensor element of FIG. 1. It is a typical side view of the filamentous distortion sensor element of embodiment different from FIG. 1 of this invention. FIG. 4 is a schematic axial cross-sectional view of a thread-like strain sensor element of an embodiment different from FIGS. 1 and 3 of the present invention. FIG. 5 is a schematic axial cross-sectional view of a thread-like strain sensor element according to an embodiment different from FIGS. 1, 3, and 4 of the present invention.

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

[First embodiment]
1 includes a core material 2 and a protective layer 3 that covers the peripheral surface of the core material. The thread-like strain sensor element 1 detects the expansion / contraction strain by measuring the resistance value between both ends of the core material 2.

<Core>
The core material 2 includes a plurality of carbon nanotubes 4 that are aligned in one direction. Specifically, the core material 2 is a fiber bundle in which a plurality of fibers including carbon nanotubes 4 and insulating fibers 5 are oriented in a substantially constant direction.

  The core material 2 has conductivity by forming a current path by contacting and electrically connecting a plurality of carbon nanotubes 4 aligned in one direction while being overlapped with each other. The core body 2 having such a configuration exhibits a certain level of electrical resistance, particularly when the contact area between the carbon nanotubes 4 is limited. When the core material 2 expands and contracts in the longitudinal direction, the contact state between the carbon nanotubes 4 changes, and the resistance value of the core material 2 changes.

  The lower limit of the average diameter of the core material 2 is preferably 0.5 μm and more preferably 5 μm. On the other hand, the upper limit of the average diameter of the core material 2 is preferably 5 mm, and more preferably 1 mm. When the average diameter of the core material 2 is less than the lower limit, continuous contact of the carbon nanotubes 4 cannot be ensured, and there is a possibility that conduction cannot be obtained. Conversely, when the average diameter of the core material 2 exceeds the upper limit, it may not be easy to form the core material 2, or the carbon nanotubes 4 at the center of the core material 2 move irregularly and detection accuracy is increased. May be insufficient.

(carbon nanotube)
As the carbon nanotubes 4 contained in the core material 2, either single-wall single-wall nanotubes (SWNT) or multi-wall multi-wall nanotubes (MWNT) can be used. Among these, MWNT is preferable from the viewpoint of conductivity and heat capacity, and MWNT having a diameter of 1.5 nm to 100 nm is more preferable.

  The carbon nanotubes 4 can be manufactured by a known method, for example, CVD method, arc method, laser ablation method, DIPS method, CoMoCAT method and the like. Among these, it is preferable that the carbon nanotube 4 (MWNT) having a desired size can be efficiently obtained by a CVD method using iron as a catalyst and ethylene gas. In this case, a crystal of carbon nanotubes 4 having a desired length which is grown in a vertical orientation on an iron or nickel thin film as a catalyst is formed on a substrate such as a quartz glass substrate or a silicon substrate with an oxide film. Can do.

(Insulating fiber)
The insulating fiber 5 has a function of adjusting the electrical resistivity of the core material 2 by suppressing contact between the carbon nanotubes 4 by being mixed with the carbon nanotubes 4.

  The blending ratio of the insulating fibers 5 is determined according to the electrical resistance to be obtained. As a general theory, the lower limit of the blending ratio of the insulating fibers 5 in the core material 2 is 0%. On the other hand, the upper limit of the blending ratio of the insulating fibers 5 is preferably 50% by volume. Setting the blending ratio of the insulating fibers 5 to 0% means that the core material 2 is formed of only the carbon nanotubes 4. Moreover, when the mixture rate of the insulating fiber 5 exceeds the said upper limit, the contact between the carbon nanotubes 4 becomes uncertain, and there exists a possibility that the detection accuracy of the said thread-like distortion sensor element 1 may become inadequate.

  As the insulating fiber 5, any chemical fiber can be used. The stretchability of the insulating fiber 5 is not essential, but the strength of the core material 2 can be improved by using the stretchable insulating fiber 5. Examples of the stretchable fiber that can be used as the insulating fiber 5 include spandex (stretchable urethane fiber).

  Further, the diameter of the insulating fiber 5 can be set to the same level as that of the carbon nanotube 4.

  As a method of forming the core material 2 by aligning the carbon nanotubes 4 in one direction, a catalyst layer is formed on a growth substrate, and a plurality of carbon nanotubes 4 oriented in a certain direction are grown by a CVD method. In the same way as natural yarn is spun, a method of continuously pulling out a plurality of carbon nanotubes 4 can be mentioned. The mixed yarn of the insulating fibers 5 can be obtained by, for example, spreading the insulating fibers 5 on a growth substrate on which the carbon nanotubes 4 are formed. That is, by pulling out some of the carbon nanotubes 4 on the growth substrate, the other carbon nanotubes 4 and the insulating fibers 5 follow and are aligned in one direction and drawn into a continuous thread shape. This filamentous body may be used as the core material 2 as it is, or a bundle of a plurality of filamentous bodies may be used as the core material 2.

<Protective layer>
The protective layer 3 is composed mainly of a synthetic resin or rubber having insulating properties and stretchability, and covers the peripheral surface of the core material 2 so that the carbon nanotubes 4 are in contact with the surrounding objects and are damaged. This prevents the foreign matter from entering the material 2 and hindering electrical contact between the carbon nanotubes 4.

  The protective layer 3 is preferably impregnated into at least a part of the surface layer of the core material 2. As described above, the protective layer 3 retains the carbon nanotubes 4 and the insulating fibers 5 on the outer peripheral side of the core material 2 by impregnating at least a part of the surface layer of the core material 2. The function of assisting in maintaining the mutual positional relationship of the five can be achieved. As a result, the detection sensitivity and resistance change linearity of the filamentous strain sensor element 1 can be further improved. Furthermore, by providing a difference in the degree of impregnation of the protective layer 3 into the surface layer of the core material 2, a portion that is easily stretched and a portion that is difficult to stretch are formed to induce partial expansion and contraction of the core material 2. The responsiveness of the sensor element 1 can be further enhanced. However, since the protective layer 3 covers the carbon nanotubes 4 and prevents electrical contact between the carbon nanotubes 4, the protective layer 3 must not be completely impregnated to the center of the core material 2. That is, by having the non-impregnated portion surrounded by the impregnated portion of the protective layer 3 in the radial direction inside the core material 2, it is possible to prevent the deformation in the orientation direction of the core material 2 from being hindered by the resin.

  The lower limit of the average thickness of the protective layer 3 on the outer peripheral surface of the core material 2 is preferably 0.1 μm, and more preferably 0.2 μm. On the other hand, the upper limit of the average thickness of the protective layer 3 on the outer peripheral surface of the core material 2 is preferably 2 mm, and more preferably 1 mm. When the average thickness of the protective layer 3 on the outer peripheral surface of the core material 2 is less than the lower limit, the protection of the core material 2 may be insufficient. On the contrary, when the average thickness of the protective layer 3 on the outer peripheral surface of the core material 2 exceeds the upper limit, the expansion and contraction of the thread-like strain sensor element 1 may be hindered.

  As the main component of the protective layer 3, rubber is particularly preferable. By using rubber, the flexibility of the protective layer 3 can be further increased.

  Examples of the synthetic resin include phenol resin (PF), epoxy resin (EP), melamine resin (MF), urea resin (urea resin, UF), unsaturated polyester (UP), alkyd resin, polyurethane (PUR), heat Curable polyimide (PI), polyethylene (PE), high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene (PS), polyvinyl acetate (PVAc), acrylonitrile butadiene styrene resin (ABS), acrylonitrile styrene resin (AS), polymethyl methacrylate (PMMA), polyamide (PA), polyacetal (POM), polycarbonate (PC), modified Polyphe Ether (m-PPE), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and cyclic polyolefin (COP) and the like.

  Examples of the rubber include natural rubber (NR), butyl rubber (IIR), isoprene rubber (IR), ethylene / propylene rubber (EPDM), butadiene rubber (BR), urethane rubber (U), and styrene / butadiene rubber (SBR). , Silicone rubber (Q), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), acrylonitrile butadiene rubber (NBR), chlorinated polyethylene (CM), acrylic rubber (ACM), epichlorohydrin rubber (CO, ECO), Fluoro rubber (FKM), PDMS, etc. can be mentioned. Among these rubbers, natural rubber is preferable from the viewpoint of strength.

  The protective layer 3 is preferably formed from an aqueous emulsion. An aqueous emulsion refers to an emulsion in which the main component of the dispersion medium is water. Since the carbon nanotubes 4 are highly hydrophobic, when the protective layer 3 is formed from an aqueous emulsion, the protective layer 3 is not impregnated in the entire core 2 by providing the protective layer 3 by coating or dipping, for example. It can be set as the state filled with the circumference | surroundings of the core material 2, or a part of surface layer. By doing in this way, it can suppress that resin which forms the protective layer 3 penetrates into the inside of the core material 2, and influences the resistance change of the said thread-like distortion sensor element. In addition, the water-based emulsion can form the more stable protective layer 3 by passing through a drying process.

  The main component of the dispersion medium of the aqueous emulsion is water, but other hydrophilic dispersion medium such as alcohol may be contained. The dispersoid of the emulsion is usually a resin, and the above-described rubber, particularly natural rubber is preferable. Further, polyurethane may be used as the dispersoid. Preferred emulsions include so-called latexes in which the dispersion medium is water and rubber is a dispersoid, and natural rubber latex is more preferable. By using natural rubber latex, a thin and strong protective layer 3 can be formed.

  Moreover, the protective layer 3 is good to contain the coupling agent. When the protective layer 3 contains a coupling agent, the protective layer 3 and the core material 2 can be cross-linked and the bonding force between the protective layer 3 and the core material 2 can be improved.

  As said coupling agent, amino coupling agents, such as an aminosilane coupling agent, an amino titanium coupling agent, and an amino aluminum coupling agent, a silane coupling agent, etc. can be used, for example.

  As a minimum of content to 100 mass parts of resin components of protective layer 3 of a coupling agent, 0.1 mass part is preferred and 0.5 mass part is more preferred. On the other hand, as an upper limit of content with respect to 100 mass parts of resin components of the protective layer 3 of a coupling agent, 10 mass parts is preferable and 5 mass parts is more preferable. When content of a coupling agent is less than the said minimum, there exists a possibility that formation of the crosslinked structure of the core material 2 and the protective layer 3 may become inadequate. On the other hand, when the content of the coupling agent exceeds the upper limit, residual amine or the like that does not form a crosslinked structure increases, and the quality of the thread-like strain sensor element 1 may be deteriorated.

  Further, the protective layer 3 preferably contains a dispersant having an adsorptivity to the core material 2. Examples of such a dispersing agent having an adsorptive property include those in which the adsorbing group portion has a salt structure (for example, an alkylammonium salt), and a hydrophobic group of the core material 2 (for example, an alkyl chain or an aromatic ring). Those having a hydrophilic group (for example, polyether etc.) in the molecule that can interact with the molecule can be used.

  As a minimum of content to 100 mass parts of resin components of protective layer 3 of the above-mentioned dispersing agent, 0.1 mass part is preferred and 1 mass part is more preferred. On the other hand, as an upper limit of content with respect to 100 mass parts of resin components of the protective layer 3 of a dispersing agent, 5 mass parts is preferable and 3 mass parts is more preferable. When the content of the dispersant is less than the lower limit, the bonding force between the core material 2 and the protective layer 3 may be insufficient. On the contrary, when the content of the dispersant exceeds the upper limit, the dispersant that does not contribute to the bonding with the core material 2 increases, and the quality of the thread-like strain sensor element 1 may be deteriorated.

<Advantages>
The thread-like strain sensor element 1 has a stretchable protective layer 3 covering the peripheral surface of the core material 2, so that the contact relationship between the plurality of carbon nanotubes 4 can be achieved without hindering the expansion and contraction of the core material 2. Since it is held, a relatively large stretch distortion can be detected with high accuracy.

  Since the thread-like strain sensor element 1 is thread-like, it can be sewn as a sewing thread on a cloth such as clothes, and can be used as a sensor for detecting expansion and contraction of the cloth.

[Strain sensor element]
The strain sensor element of FIG. 2 is formed by weaving the thread-like strain sensor element 1 of FIG. Specifically, the fabric-like strain sensor element is a fabric using a plurality of yarn-like strain sensor elements 1 as warp yarns and normal yarns made of natural fibers or chemical fibers as weft yarns 6.

  The fabric-like strain sensor element includes a pair of connection terminals 7 that connect both ends of the plurality of thread-like strain sensor elements 1. The connection terminal 7 is electrically connected to the core material 2 of each thread strain sensor element 1.

  The fabric-like strain sensor element detects expansion and contraction in the longitudinal direction of each thread-like strain sensor element 1.

<Advantages>
In the fabric-like strain sensor element, the weft 6 forms a node that partially suppresses expansion and contraction of the yarn-like strain sensor element 1. For this reason, in the fabric-like strain sensor element, the portion between these nodes of the thread-like strain sensor element 1 is intensively expanded and contracted, and the change in the contact state between the carbon nanofibers 4 is ensured even for a small strain. Therefore, the linearity is high and the detection sensitivity is excellent. Further, even when a force that locally stretches the cloth-like strain sensor element is applied, the yarn-like strain sensor element 1 is locally disposed between the wefts 6 that form a pair of portions where the force is applied, that is, between adjacent nodes. Therefore, local expansion / contraction distortion can be detected with high accuracy.

  The cloth-like strain sensor element can be stitched with another cloth to constitute a part of a cloth such as clothes. Thereby, the wearable device which detects a motion of a human body can be comprised easily.

[Second Embodiment]
3 includes a core material 2, a protective layer 3 covering the peripheral surface of the core material, a node forming member 11 wound spirally around the outer peripheral surface of the protective layer 3, and the protective layer 3. And an elastomer layer 12 that covers the outer peripheral surface of the node forming member 11.

  The core material 2 and the protective layer 3 in the thread-like strain sensor element 10 in FIG. 3 are the same as the core material 2 and the protective layer 3 in the thread-like strain sensor element 1 in FIG.

<Knot forming member>
The node forming member 11 is partially wound around the protective layer 3 to partially restrict the expansion and contraction of the region located immediately below the node forming member 11 of the protective layer 3 and the core material 2.

  Thereby, the expansion / contraction area | region of the core material 2 is limited, and when the expansion stress acts on a part of the longitudinal direction of the said thread-like distortion sensor element 10, the core material 2 is partially expanded and contracted, and the resistance value of the core material 2 Make a change. For this reason, the said thread-like distortion sensor element 10 changes a resistance value linearly also with respect to such a partial expansion-contraction distortion, and can detect an expansion-contraction distortion accurately.

  As the node forming member 11, a linear body or a strip-shaped body is used. The material of the node forming member 11 may be any material as long as it has flexibility to be wound around the protective layer 3 in a spiral manner, and examples thereof include metals and resins. Even if the node forming member 11 does not have elasticity, it can be expanded and contracted together with the core material 2 and the protective layer 3 by being wound spirally.

  The average diameter of the node forming member 11 wound in a spiral shape (average width in the case of a band-like body) can be set to, for example, 10 μm or more and 500 μm or less. Further, the winding pitch of the node forming member 11 may be 1.5 times or more the average diameter of the node forming member 11 and not more than the average diameter of the protective layer 3.

  Further, by using a conductive member as the node forming member 11, the node forming member 11 can be used as a part of the wiring for measuring the electrical resistance of the core material 2. That is, the core material 2 and the node forming member 11 are short-circuited at one end of the thread-like strain sensor element 10, and the detection circuit is connected between the core material 2 and the node forming member 11 at the other end. The electrical resistance between both ends can be measured.

  Further, the conductive node forming member 11 can also function as a shield or a ground for blocking electromagnetic noise from the outside to the core member 2.

  Examples of the conductive node forming member 11 include a metal thread and a ribbon obtained by cutting a metal film deposited on a resin film into a strip shape.

<Elastomer layer>
The elastomer layer 12 further reinforces the function of the protective layer 3 and prevents displacement of the node forming member 11 with respect to the protective layer 3.

  The material of the elastomer layer 12 can be the same as that of the protective layer 3.

  As a minimum of average thickness of elastomer layer 12, 10 micrometers is preferred and 50 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the elastomer layer 12 is preferably 5 mm, and more preferably 2 mm. If the average thickness of the elastomer layer 12 is less than the lower limit, there is a possibility that the displacement of the node forming member 11 cannot be prevented. Conversely, when the average thickness of the elastomer layer 12 exceeds the upper limit, the thread-like strain sensor element 10 may unnecessarily increase in diameter.

<Advantages>
Since the thread-like strain sensor element 10 has the node forming member 11 as described above, even when a part of the longitudinal direction is partially expanded and contracted, the expansion and contraction strain can be accurately detected.

[Third embodiment]
4 includes a core member 2, a protective layer 3 covering the peripheral surface of the core member, and a plurality of annular node forming members 21 disposed on the outer peripheral surface of the protective layer 3. The protective layer 3 and the elastomer layer 12 covering the outer peripheral surfaces of the plurality of node forming members 21 are provided.

  The core material 2, protective layer 3 and elastomer layer 12 in the thread strain sensor element 20 of FIG. 4 are the core material 2 and protective layer 3 of the thread strain sensor element 1 of FIG. 1 and the elastomer layer of the thread strain sensor element 10 of FIG. 12 is the same as in FIG.

<Knot forming member>
The node forming member 21 is disposed in close contact with the outer peripheral surface of the protective layer 3 at an arbitrary interval, thereby partially expanding and contracting the protective layer 3 and the region located immediately below the node forming member 21 of the core material 2. regulate. The node forming members 21 may be arranged at equal intervals, or may be arranged at partially different intervals according to the use of the thread-like strain sensor element 20.

  As this node forming member 21, for example, an annular heat shrink film (heat-shrinkable tube cut short) that is heated after being fitted to the outer periphery of the protective layer 3, various curable properties that are cured after being placed on the outer peripheral surface of the protective layer 3 Examples thereof include resins.

  The average thickness of the node forming member 21 can be, for example, 10 μm or more and 1 mm or less. The average width of the node forming member 21 is appropriately selected depending on the application, but may be, for example, 100 μm or more and 10 mm or less.

<Advantages>
In the thread-like strain sensor element 20, since the plurality of node forming members 21 are independently provided, the expansion and contraction of a desired position of the core material 2 can be selectively restricted. In addition, since the plurality of node forming members 21 are separated from each other, high detection sensitivity is obtained without interfering with the expansion and contraction of the core material 2 and the protective layer 3 between the node forming members 21.

[Fourth embodiment]
5 includes a core member 2, a protective layer 3 covering the peripheral surface of the core member, a plurality of node forming members 31 disposed on the outer peripheral surface of the protective layer 3, and the node formation. And an elastomer layer 32 that is integrally formed with the member 31 and covers the protective layer 3.

  The core material 2 and the protective layer 3 in the thread-like strain sensor element 30 in FIG. 5 are the same as the core material 2 and the protective layer 3 in the thread-like strain sensor element 1 in FIG.

  The node forming member 31 and the elastomer layer 32 are formed by applying a resin composition to the outer peripheral surface of the protective layer 3, and by changing the thickness of the coating film, the core material 2 and A node forming member 31 that partially restricts expansion and contraction of the protective layer 3 is formed.

  As a method of forming such a node forming member 31 and the elastomer layer 32, it can form by vibrating the die | dye which coats a resin composition, or roughening the surface of a coating film by spraying air.

  The maximum protrusion height of the node forming member 31 from the elastomer layer 32 can be, for example, 1 to 5 times the average thickness of the elastomer layer 32.

[Other Embodiments]
The said embodiment does not limit the structure of this invention. Therefore, in the above-described embodiment, components of each part of the above-described embodiment can be omitted, replaced, or added based on the description and common general knowledge of the present specification, and they are all interpreted as belonging to the scope of the present invention. Should.

  In the second to fourth embodiments of the thread strain sensor element, either one of the elastomer layer and the node forming member may be omitted.

  Further, in the thread-like strain sensor element, the node forming member may be disposed not on the inner side of the elastomer layer but on the outer peripheral surface of the elastomer layer.

  In the thread-like strain sensor element, the node forming member may be formed integrally with the protective layer.

  The fabric-like strain sensor element may be woven using the yarn-like strain sensor element as a weft. In this case, if the width of the woven fabric is used as it is, the respective thread strain sensor elements are connected in series. Therefore, the electrical resistance between the ends of the respective thread strain sensor elements at both ends in the longitudinal direction of the cloth is set. Stretching distortion may be detected by measuring.

  Further, the fabric-like strain sensor element may be configured to detect bi-directional stretching strain by using the yarn-like strain sensor element for both warp and weft.

  In addition, the fabric-like strain sensor element may be a fabric woven using the yarn-like strain sensor element as part of the warp or weft.

  The fabric-like strain sensor element may be a knitted fabric knitted using at least a part of the yarn-like strain sensor element.

  The thread-like strain sensor element and the fabric-like strain sensor element of the present invention can be suitably used as a sensor for a wearable device or the like.

1, 10, 20, 30 Threaded strain sensor element 2 Core material 3 Protective layer 4 Carbon nanotube 5 Insulating fiber 6 Weft 7 Connection terminal 11, 21, 31 Node forming member 12, 32 Elastomer layer

Claims (4)

A core material including a plurality of carbon nanotubes aligned in one direction;
Covering the peripheral surface of this core material, and comprising a protective layer mainly composed of a synthetic resin or rubber having elasticity ,
A thread-like strain sensor element further comprising a node forming member disposed on the outer peripheral surface of the protective layer and partially restricting expansion and contraction of the protective layer . The thread-like strain sensor element according to claim 1 , wherein the node forming member is a linear body or a belt-like body wound spirally around the outer peripheral surface of the protective layer. The thread-like strain sensor element according to claim 2 , wherein the node forming member has conductivity. A fabric-like strain sensor element obtained by knitting or weaving the thread-like strain sensor element according to any one of claims 1 to 3 .

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