JP2017129417A - Strain sensor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a strain sensor element that can be attached to cloth relatively easily.SOLUTION: A strain sensor element comprises: a belt-like or filamentous detection part 1, the electric resistance of which changes in accordance with a strain in the longitudinal direction; and a pair of needle-shaped parts 2, each disposed at a longitudinal end of the detection part 1, the width of which gradually decreases toward the tip side. The pair of needle-shaped parts 2 may preferably be a pair of electrodes connected to both ends of the detection part 1. The pair of needle-shaped parts 2 may also be a pair of sandwiched members arranged so as to face the pair of electrodes connected to both ends of the detection part 1. The needle-shaped parts 2 may preferably have a recess at side edge. The needle-shaped parts 2 may have an open hole.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a strain sensor element.

  For example, there is a need for a motion detection device that detects the movement of a human body in order to reproduce the movement of the human body in virtual reality technology used in games and the like. In addition, the use of motion detection devices is also being considered for scientific analysis of movements of athletes, for example.

  As an example of the motion detection device for detecting the movement of the human body, a cylindrical or supporter support body that is formed of a stretchable fabric and is fitted to fit around a joint such as an elbow, and the support body. And a belt-like strain sensor element including a conductive elastomer which is attached so as to be bridged between two points on both the outer side of the joint bending and extending direction and the proximal and distal directions of the joint, and which is extendable and capable of detecting the amount of expansion and contraction. A joint bending angle detection device has been proposed (see Japanese Patent Laid-Open No. 1-136632).

  In the motion detection device described in the publication, the strain sensor element is fixed to the support body by sewing a strain sensor element or a member attached to the strain sensor element to the support body formed of a fabric. As described above, when the strain sensor element is sewn on the fabric, the strain sensor element cannot be easily attached to an accurate position unless the strain sensor element is temporarily fixed to the fabric using an adhesive or the like. . However, temporarily attaching the strain sensor element is troublesome.

JP-A-1-136632

  In view of the above disadvantages, an object of the present invention is to provide a strain sensor element that is relatively easy to attach to a fabric.

  The invention made in order to solve the above-mentioned problems is provided with a strip-like or thread-like detecting portion whose electrical resistance changes according to the strain in the longitudinal direction, and arranged at both ends in the longitudinal direction of the detecting portion, the width of which is the tip side A strain sensor element comprising a pair of needle-like portions gradually decreasing.

  Since the strain sensor element is provided with a pair of needle-like portions whose width gradually decreases toward the distal end at both ends in the longitudinal direction of the detection portion, the needle-like portions can be temporarily fixed by being inserted into the fabric. It is relatively easy to attach the fabric to the correct position.

  The pair of needle-like parts may be a pair of electrodes connected to both ends of the detection part. Thus, the pair of needle-like parts is a pair of electrodes connected to both ends of the detection part, so that the number of parts is not increased due to the needle-like part, and the configuration of the strain sensor element is compared. Can be simplified.

  The pair of needle-like portions may be a pair of clamping members arranged to face a pair of electrodes connected to both ends of the detection portion. In this way, the pair of needle-like parts is a pair of clamping members disposed so as to face the pair of electrodes connected to both ends of the detection part, that is, the connection between the detection part and the electrode is more reliable. By making the pair of sandwiching members that can be provided to be needle-like portions, the number of parts for the needle-like portions is not increased, and the configuration of the strain sensor element can be made relatively simple.

  It is good to have a recessed part in the side edge part of the said acicular part. Thus, by having a recess in the side edge portion of the needle-like portion, the fabric fiber is engaged with the recess, so that the temporary fixing of the strain sensor becomes more reliable, and the fabric can be attached more easily. Become. In addition, when the strain sensor element is fixed by sewing a thread on the fabric, since the sewn thread engages with the recess, the strain sensor element is more reliably fixed.

  The needle-like portion may have a through hole. Thus, since the needle-like portion has a through hole, the strain sensor element can be more reliably fixed by sewing a thread into the through hole.

  As described above, the strain sensor element of the present invention is relatively easy to attach to the fabric.

It is a typical top view showing a distortion sensor element of one embodiment of the present invention. FIG. 2 is a schematic side view of the strain sensor element of FIG. 1. It is a typical side view which shows the temporary fix | stop state of the distortion sensor element of FIG. It is a typical side view which shows the distortion sensor element of embodiment different from FIG. 1 of this invention. FIG. 5 is a schematic side view showing a strain sensor element according to an embodiment different from FIGS. 1 and 4 of the present invention. FIG. 6 is a schematic partial plan view showing a strain sensor element according to an embodiment different from FIGS. 1, 4, and 5 of the present invention.

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

[First embodiment]
The strain sensor elements of the first embodiment of the present invention shown in FIGS. 1 and 2 are arranged in strip-like detection units 1 whose electrical resistance changes according to the strain in the longitudinal direction, and at both ends in the longitudinal direction of the detection unit 1. And a pair of needle-like portions 2 whose width gradually decreases toward the distal end side.

  In the present embodiment, the pair of needle-like parts 2 are a pair of electrodes that are electrically and mechanically connected to both ends of the detection part 1. The pair of needle-like parts 2 may be laminated and fixed so as to cover both end portions of the surface of the detection part 1.

<Detector>
Although the detection part 1 should just change an electrical resistance according to expansion and contraction, for example, a film-like detection body including a plurality of CNT fibers arranged in one direction can be used.

  As a minimum of average width of detection part 1 (film-like detection object), 0.3 mm is preferred and 0.5 mm is more preferred. On the other hand, the upper limit of the average width of the detection unit 1 is preferably 10 mm, more preferably 5 mm, and even more preferably 2 mm. When the average width of the detection unit 1 is less than the lower limit, the strength of the detection unit 1 may be insufficient. On the contrary, when the average width of the detection unit 1 exceeds the upper limit, the strain sensor element becomes large, and the applicable measurement target may be excessively limited.

  As a minimum of average thickness of detection part 1, 10 micrometers is preferred and 15 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the detection unit 1 is preferably 3 mm, and more preferably 1 mm. When the average thickness of the detection unit 1 is less than the lower limit, the strength may be insufficient. On the contrary, when the average thickness of the detection part 1 exceeds the said upper limit, when the needle-like part 2 is inserted in a fabric, the detection part 1 may buffer and may inhibit fixation of the strain sensor element.

  The average length in the longitudinal direction of the detection unit 1 is not particularly limited, and can be freely selected according to the measurement target using the strain sensor element, and can be, for example, 1 cm or more and 20 cm or less.

  The average length in the longitudinal direction of the detection region, which is sandwiched between the pair of needle-like portions 2 in the plan view and substantially expands and contracts and changes its electrical resistance, is a measurement object using the strain sensor element. It can be freely selected according to. The average length of the detection region can be, for example, 2 mm or more and 18 cm or less.

  The average length in the longitudinal direction of the fixed region that overlaps with the pair of needle-like parts 2 in the plan view and does not substantially contribute to the detection of the distortion in the detection part 1 depends on the attachment method of the needle-like part 2 and the like. Although it selects suitably, it can be 3 mm or more and 5 cm or less, for example.

  The lower limit of the electrical resistance (a value measured between the pair of needle-like parts 2) in a state where the detector 1 is not distorted is preferably 10Ω, and more preferably 100Ω. On the other hand, the upper limit of the electrical resistance in a state where the detector 1 is not distorted is preferably 100 kΩ, and more preferably 10 kΩ. When the electrical resistance in a state where the detection unit 1 is not distorted is less than the lower limit, the current for detecting the extension strain becomes large, and the power consumption of the strain sensor element may be increased. On the other hand, when the electrical resistance of the detector 1 without distortion exceeds the upper limit, it is difficult to reduce the size and power consumption of the device that processes the output of the strain sensor element by increasing the voltage of the detection circuit. There is a risk of becoming.

[Membrane-shaped detector]
The film-like detector has a layer formed of a plurality of CNT fibers aligned in one direction, and the film is formed by impregnating an insulating elastomer described later at least on the surface layer (surface vicinity region) of the CNT fiber layer. It is formed in a shape. Further, since the insulating elastomer inhibits electrical contact between the CNT fibers, a region not impregnated with the insulating elastomer remains in the center of the CNT fiber layer. Further, since the CNT fiber layer is covered with the insulating elastomer by impregnation with the insulating elastomer, it is considered that a thin layer made of the insulating elastomer is formed on the surface layer of the film-like detection body.

  Such a film-like detection body has elasticity due to the elastic force of the insulating elastomer, and can expand and contract at least in the longitudinal direction. By extending at least in the longitudinal direction, the CNT fibers are separated from each other to increase the electric resistance, and the film-like detection body contracts due to the elastic force, so that the CNT fibers are brought into contact again and the electric resistance is decreased. The film-like detector may include insulating fibers made of, for example, a synthetic resin in the CNT fiber layer in order to suppress the contact rate between the CNT fibers and adjust the electric resistance.

  Since at least the surface layer of the film-like detection body is impregnated with an insulating elastomer, the insulating elastomer covers a CNT fiber bundle described later. Therefore, the insulating elastomer guides the stretching direction of a plurality of CNT fiber bundles. It also functions as a member. As a result, the strain sensor element can re-contact the CNT fibers separated at the time of extension at the same site again at the time of contraction, and can prevent a reduction in the detection accuracy of the stretching strain due to repeated use. Furthermore, according to such a configuration, the contact relationship between the plurality of CNT fibers is easily maintained, and the stretchability of the plurality of CNT fibers is easily adjusted. Therefore, the expansion / contraction strain of the film-like detection body can be detected with higher accuracy.

  In order to further maintain the contact relationship and adjust the stretchability, it is preferable that the insulating elastomer is also impregnated in the back layer (region near the back surface) of the CNT fiber layer. At this time, since at least a part of the surface layer of the CNT fiber layer is impregnated with the insulating elastomer, the bonding strength between the CNT fiber layer and the insulating elastomer is also increased.

(CNT fiber)
Each of the CNT fibers used for the film-like detector can be formed from a plurality of CNT single fibers. Here, the CNT single fiber means one long carbon nanotube. In addition, the CNT fiber has a connection portion where the ends of the CNT single fibers are connected to each other. The CNT single fibers are connected in the longitudinal direction of these CNT single fibers. In this way, in the film-like detector, the CNT single fibers are connected in the longitudinal direction to form a layer with a large orientation length of the CNT fibers, and the length of the strain sensor element in the longitudinal direction can be increased. The sensitivity can be improved by increasing the sensitivity.

  Moreover, in the CNT fiber layer of the film-like detector, the plurality of CNT fibers may form a network structure. Specifically, the plurality of CNT fibers may be connected or contacted in a mesh shape by a connecting portion or the like where the CNT single fibers are connected to each other. At this time, the end portions of three or more CNT single fibers may be coupled to each other at this connection portion, and the end portions of the two CNT single fibers may be coupled to an intermediate portion of another single fiber. When a plurality of CNT fibers form such a network structure, the CNT fibers are in close contact with each other, and the resistance of the CNT fiber layer can be reduced.

  Furthermore, the film-like detector may have a CNT fiber bundle composed of a plurality of CNT fibers oriented in the longitudinal direction. When the film-shaped detector has a plurality of CNT fiber bundles oriented in the longitudinal direction, the CNT fibers are cut and separated when the film-shaped detector is stretched in the expansion / contraction direction, and the space for cutting the CNT fiber bundles. The resistance of the film-like detection body changes more accurately due to expansion and contraction of the (gap).

  More specifically, the CNT fiber bundle has a bundle structure composed of a plurality of CNT fibers. In an arbitrary cross section of the CNT fiber bundle, the CNT fibers that are not cut and the CNT fibers are cut and separated. Both gaps will exist. Further, since the surface layer of the plurality of CNT fiber bundles is coated with an insulating elastomer, the pressure in the gap is considered to be lower than the atmospheric pressure (negative pressure), and therefore, when the strain sensor element contracts ( When the strain is released, the strain sensor element is contracted by the contraction force of the gap. Furthermore, since the friction between the CNT fibers is reduced in the gap, the movement of the CNT fibers is difficult to be limited.

  In addition, the layer of the CNT fibers in the film-like detector may have a single-layer structure in which a plurality of CNT fibers or a plurality of CNT fiber bundles are arranged substantially in parallel in a planar shape, or may have a multilayer structure. However, in order to ensure a certain degree of conductivity, a multilayer structure is preferable.

  As the CNT single fiber, either single-wall single-wall nanotubes (SWNT) or multi-wall multi-wall nanotubes (MWNT) can be used, but MWNT is preferable from the viewpoint of conductivity and heat capacity, and a diameter of 1. MWNT of 5 nm or more and 100 nm or less is more preferable.

  The CNT single fiber can be produced by a known method, for example, CVD (chemical vapor deposition) method, arc method, laser ablation method, DIPS (direct injection pyrolysis synthesis) method, It can be manufactured by the CoMoCAT method (trademark) or the like. Among these, it is preferable to produce by a CVD method using iron as a catalyst and ethylene gas from the viewpoint that carbon nanotubes (MWNT) having a desired size can be efficiently obtained. In this case, a carbon nanotube crystal having a desired length is obtained by forming a catalyst iron or nickel thin film on a substrate such as a quartz glass substrate or a silicon substrate with an oxide film and vertically growing the carbon nanotubes. Can be obtained.

(Insulating elastomer)
As described above, the insulating elastomer is impregnated in the CNT fiber layer and forms a layer covering the surface of the CNT fiber layer, and has a function of imparting elastic force to the strain sensor element. The insulating elastomer layer covering one surface of the film-like detector can be distinguished by being called a substrate layer, and the insulating elastomer layer covering the other surface of the film-like detector can be called a protective layer. As the insulating elastomer impregnated in the CNT fiber layer of the film-like detector, for example, rubber, styrene elastomer, olefin elastomer, vinyl chloride elastomer, urethane elastomer, amide elastomer and the like can be used.

  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), Examples thereof include fluororubber (FKM) and polydimethylsiloxane (PDMS). Among these, natural rubber is preferable from the viewpoint of strength and the like.

  The insulating elastomer may be impregnated in a layer of CNT fibers by application of an aqueous emulsion. The aqueous emulsion refers to an emulsion in which the main component of the dispersion medium is water. Since carbon nanotubes are highly hydrophobic, when an insulating elastomer is coated by application using an aqueous emulsion, the insulating elastomer does not completely enter between a plurality of CNT fibers. That is, the insulating elastomer is partially impregnated between the plurality of CNT fibers, but this insulating elastomer is not impregnated in the entire region in the cross section in the thickness direction of each CNT fiber. As a result, the insulating elastomer is completely infiltrated between the plurality of CNT fibers to suppress the change in resistance of the film-shaped detector, and the sensitivity to the distortion of the film-shaped detector due to the presence of the insulating elastomer is suppressed. Can be suppressed.

  The main component of the dispersion medium of the aqueous emulsion is water, but other hydrophilic dispersion medium such as alcohol may be contained.

  Preferred emulsions include so-called latexes in which the dispersion medium is water and rubber is a dispersoid, and natural rubber latex is preferred. By using natural rubber latex, a thin and strong film can be formed.

  The insulating elastomer may contain a coupling agent. When the insulating elastomer contains a coupling agent, the insulating elastomer and the CNT fiber can be cross-linked, and the bonding strength between the insulating elastomer and the CNT fiber 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.

  Moreover, it is preferable that the insulating elastomer contains a dispersant having an adsorptivity to the CNT fiber. Examples of such an adsorbent dispersant include those having an adsorption group portion having a salt structure (eg, alkylammonium salt), hydrophobic groups of CNT fibers (eg, alkyl chains and aromatic rings), and the like. The thing etc. which have the hydrophilic group (for example, polyether etc.) which can interact in a molecule | numerator can be used.

  An assist layer made of a different resin material may be further laminated on the surface of the insulating elastomer layer. By adopting a resin material having excellent elasticity and durability as a material different from the insulating elastomer, the stretchability and durability of the strain sensor element can be enhanced. Specifically, a urethane resin is preferable as a material different from the insulating elastomer.

<Needle part>
The pair of needle-like parts 2 are used as terminals for connecting wires for measuring the electrical resistance of the detection part 1 and are inserted into the cloth when the distortion sensor element is fixed to the cloth, thereby the distortion sensor. Used to temporarily fix the element. In other words, the strain sensor element is temporarily fixed to the fabric using, for example, a curable adhesive after temporarily fixing the needle-like portion 2 to an accurate position by inserting the needle-like portion 2 into the fabric.

  The electrical connection method between the needle-like part 2 and the CNT fiber layer of the detection part 1 is not particularly limited. For example, the insulating elastomer on the surface of the protective layer and the CNT fiber layer is removed by laser irradiation or the like. A method of directly contacting the exposed carbon nanotubes, an end surface (for example, a side surface of the CNT fiber layer, an inner peripheral surface of a through hole formed in the CNT fiber layer) and the needle-like portion 2 of the CNT fiber layer. And a method in which a conductive adhesive or the like is placed so as to straddle, and a method in which a protrusion that reaches the CNT fiber layer and is inserted into the detection unit 1 is provided on the needle-like unit 2.

  Moreover, the needle-like part 2 can be fixed to the detection part 1 using an adhesive. As this adhesive, for example, a pressure-sensitive adhesive, a curable adhesive, a thermoplastic adhesive, or the like can be used. As said adhesive, an acrylic adhesive etc. are mentioned, for example. Examples of the curable adhesive include an epoxy adhesive. In addition, when a conductive adhesive containing a conductive filler in a synthetic resin is used as the adhesive, the detection part 1 and the needle-like part 2 can be electrically fixed and mechanically fixed simultaneously.

  Further, by placing the adhesive on the end face in the longitudinal direction of the detection unit 1, the step between the needle-like part 2 and the detection part 1 can be smoothed, whereby the detection part 1 follows the needle-like part 2. It becomes easy to insert the edge part of this into the fabric.

  The material constituting the needle-like portion 2 is not particularly limited as long as it has sufficient strength and conductivity, but a metal is preferably used. Examples of the metal constituting the needle-like portion 2 include copper, aluminum, nickel, stainless steel, etc. Among them, nickel and stainless steel having rigidity are preferably used.

  As a minimum of average thickness of acicular part 2, 0.2 mm is preferred and 0.5 mm is more preferred. On the other hand, as an upper limit of the average thickness of the acicular part 2, 3 mm is preferable and 1 mm is more preferable. When the average thickness of the needle-like part 2 is less than the lower limit, the rigidity may be insufficient and it may be difficult to insert into the fabric. Conversely, if the average thickness of the needle-like part 2 exceeds the upper limit, it may be difficult to insert the end part of the detection part 1 between the fibers of the fabric.

  It is preferable that the average width of the portion fixed to the detection unit 1 of the needle-like unit 2 (usually, this is the maximum width) is substantially equal to the average width of the detection unit 1. When the average width of the part fixed to the detection part 1 of the needle-like part 2 is smaller than the average width of the detection part 1, it may not be easy to insert the detection part 1 into the fabric. When the average width of the portion fixed to the detection unit 1 of the needle-like unit 2 is larger than the average width of the detection unit 1, it may be difficult to pull back the strain sensor element once it has been inserted into the fabric.

  When the average width of the portion fixed to the detection portion 1 of the needle-like portion 2 is larger than the average width of the detection portion 1, the range of the average width of the portion extending from the detection portion 1 of the needle-like portion 2 is from 0 mm It is large and preferably 0.5 mm or less. When the above range is exceeded, as described above, it may be difficult to pull back the strain sensor element after it is once stabbed into the fabric. In addition, when the average width of the part fixed to the detection part 1 of the needle-like part 2 is smaller than the average width of the detection part 1, the detection part 1 extended from the needle-like part 2 is inserted into and removed from the fabric in a folded state. May be.

  As shown in the figure, the planar shape of the needle-like portion 2 may be bilaterally symmetric about the longitudinal axis, but may be bilaterally asymmetric. In addition, the needle-like portion 2 is formed so that the width of the portion extending from the detection portion 1 becomes discontinuously smaller than the width of the portion fixed to the detection portion 1 when not inserted into the fabric until the detection portion 1. May be. Moreover, as a front-end | tip shape of the needle-shaped part 2, what is necessary is just to become thin to such an extent that it can be inserted in the fabric used, and the front-end | tip shape may be the shape rounded and chamfered. In addition, the needle-like portion 2 may be formed so that not only the width but also the thickness gradually decreases toward the distal end side. However, by having a certain thickness, the needle-like portion 2 is relatively easy by punching from a plate material or the like. Can be formed.

<Advantages>
Since the strain sensor element has a pair of needle-like portions 2 whose width gradually decreases toward the distal end side at both ends of the detection portion 1 that converts expansion / contraction strain into a change in electrical resistance, for example, as shown in FIG. By inserting the needle-like portion 2 into the fabric C, it can be temporarily fixed to the fabric C relatively easily. Thus, since the strain sensor element is relatively easy to attach to the fabric, the wearable device that detects the movement of the human body can be easily manufactured by using the strain sensor element.

  In addition, since the strain sensor element includes the needle-like portion 2 that is also an electrode, the strain sensor element can be connected to the measurement circuit by inserting the needle-like portion 2 into a conductive wiring formed in advance on the fabric.

[Second Embodiment]
The strain sensor element according to the first embodiment of the present invention shown in FIG. 4 is disposed on a belt-like detection unit 11 whose electric resistance changes in accordance with strain in the longitudinal direction, and on both ends in the longitudinal direction of the detection unit 11. A pair of electrodes 12 and a pair of needle-like portions 13 that are disposed so as to face the pair of electrodes 12 via the detection portion 11 and whose width gradually decreases toward the distal end side are provided.

  In the present embodiment, the pair of needle-like parts 13 are a pair of clamping members that secure the connection between the detection part 11 and the electrode 12 by sandwiching the detection part 11 between the pair of electrodes 12.

  The detection unit 11 in the strain sensor element of FIG. 4 can be the same as the detection unit 1 in the strain sensor element of FIG. For this reason, the overlapping description about the detection part 11 of the distortion sensor element of FIG. 4 is abbreviate | omitted.

<Electrode>
The pair of electrodes 12 are mechanically fixed to the surface side of both ends of the detection unit 11 and are electrically connected to the CNT fiber layer of the detection unit 11. The pair of electrodes 12 is used as a pair of terminals for electrically extracting a detection signal of the strain sensor element.

  The material of the pair of electrodes 12 is conductive and does not substantially expand and contract during use of the strain sensor element. Note that “substantially does not expand / contract” means that the longitudinal direction of the electrode 12 with respect to the longitudinal expansion / contraction ratio during measurement using the strain sensor element in the detection region between the pair of electrodes 12 in a plan view of the detection unit 11. It means that the ratio of the stretch ratio is 1/100 or less, preferably 1/1000 or less. The number of digits of the ratio of the expansion / contraction area to the expansion / contraction ratio of the electrode 12 during measurement using the strain sensor element is preferably larger than the number of effective numerical values in the measurement, and more than two digits. More preferred.

  The material constituting the electrode 12 is not particularly limited as long as it has sufficient non-stretchability (tensile strength) and conductivity, and for example, metal foil, conductive cloth or the like is used. The electrode 12 may be a laminate having at least a conductive layer disposed on the outer surface and a reinforcing material layer that imparts non-stretchability. Examples of the material of the metal foil include copper, aluminum, nickel, and stainless steel. Moreover, as said conductive cloth, the woven fabric and nonwoven fabric which contain the fiber which has electroconductivity at least on the surface can be used. Furthermore, the surface of the electrode 12 may be coated with a material that is not easily corroded, such as gold. Moreover, you may comprise the electrode 12 by coat | covering the surface of ceramics with gold | metal | money etc.

  As a minimum of average thickness of electrode 12, 10 micrometers is preferred and 50 micrometers is more preferred. On the other hand, the upper limit of the average thickness of the electrode 12 is preferably 1 mm, and more preferably 0.5 mm. When the average thickness of the electrode 12 is less than the lower limit, the electrode 12 may be broken by bending or the like. On the other hand, when the average thickness of the electrode 12 exceeds the upper limit, the strain sensor element may be unnecessarily thick, or the needle-like portion 13 may be prevented from being inserted into the fabric.

  As a method of connecting the electrode 12 to the CNT fiber layer of the detection unit 11 in the strain sensor element of FIG. 4, a method of connecting the needle-like part 2 of the detection unit 1 to the CNT fiber layer of the strain sensor element of FIG. The same can be said.

<Needle part>
The needle-like portion 13 in the strain sensor element of FIG. 4 is a clamping member that suppresses deformation of the fixed region where the electrode 12 of the detection unit 11 is laminated by sandwiching the end of the detection unit 11 between the electrode 12 and the needle-like portion 13. is there. With such a configuration, the strain sensor element expands and contracts only the detection region of the detection unit 11 to improve detection accuracy.

  Moreover, the needle-like part 13 protrudes in the longitudinal direction from the detection part 11 and the electrode 12 in a plan view, and the width of at least a part of the protruding part gradually decreases toward the distal end side. Thereby, since the said strain sensor element can insert the needle-like part 13 in a cloth and can be temporarily fixed, it can be attached to a cloth comparatively easily and correctly.

  The material of the needle-like portion 13 may be any material that has sufficient rigidity, and may be conductive or insulating. Specifically, as the acicular portion 13, for example, a resin composition mainly composed of polyimide, polyethylene terephthalate, or the like, or a metal such as nickel, stainless steel, copper, or aluminum can be used.

  The average thickness of the needle-like portion 13, the average width of the portion fixed to the detection portion 11 and the average width of the portion extending from the detection portion 11 in the strain sensor element of FIG. The average thickness of the needle-like portion 2 in the strain sensor element, the average width of the portion fixed to the detection portion 1, and the average width of the portion extending from the detection portion 1 can be set.

  The opposing electrode 12 and the needle-like part 13 may be clamped by fastening members (not shown) such as bolts, rivets, clamps, and the like. This fastening member may penetrate through the detection unit 11, the electrode 12, and the needle-like unit 13, and may also serve as a member for electrically connecting the electrode 12 to the detection unit 11.

  The acicular part 13 can be laminated | stacked on the detection part 11, for example using an adhesive agent. As this adhesive, the same adhesive as that used for laminating the electrodes 12 can be used, but it is preferable to use an adhesive having no electrical conductivity.

[Third embodiment]
The strain sensor element according to the first embodiment of the present invention shown in FIG. 5 is provided on a belt-like detection unit 21 whose electrical resistance changes according to the strain in the longitudinal direction, and on both ends in the longitudinal direction of the detection unit 11. A first needle-like part 22 and a second needle-like part 23 arranged to face the pair of needle-like parts 22 via the detection part 21 are provided.

  In this embodiment, a pair of 1st acicular part 22 is an electrode for measuring the electrical resistance of the detection part 21, and a pair of 2nd acicular part 23 is between a pair of 1st acicular part. By sandwiching the detection unit 21 between the two, a stretchable region of the detection unit 21 is accurately determined, and the clamping member improves the detection accuracy of the stretch distortion by the strain sensor element.

  The detection part 21 and the first needle-like part 22 in the strain sensor element of FIG. 5 can be the same as the detection part 1 and the needle-like part 2 in the strain sensor element of FIG. Further, the second needle-like portion 23 in the strain sensor element of FIG. 5 can be the same as the needle-like portion 13 in the strain sensor element of FIG. For this reason, the overlapping description about the strain sensor element of FIG. 5 is omitted.

  In the strain sensor element, the first needle-like portion 22 and the second needle-like portion 23 facing each other function as one needle. When the thickness of the detection portion 21 is relatively large, the first needle-like portion 22 and the second needle-like portion 23 are configured to be in close contact with each other by being bent, twisted together, or formed on each of them. It is preferable to integrate by notching a notch.

  As described above, the strain sensor element has the first needle-like portion 22 that is an electrode and the second needle-like portion 23 that is a clamping member, so that the thickness of the strain sensor element is sharply increased on both sides. Since the detection unit 21 is not easily caught by the fabric when the first needle-like portion 22 and the second needle-like portion 23 are inserted into the fabric, the attachment to the fabric is easier.

[Fourth embodiment]
The strain sensor element according to the fourth embodiment of the present invention shown in FIG. 6 is disposed on each of the strip-shaped detection unit 1 whose electric resistance changes according to the strain in the longitudinal direction, and both ends of the detection unit 1 in the longitudinal direction. A needle-like portion 2a.

  The configuration of the strain sensor element of FIG. 6 is the same as the configuration of the strain sensor element of FIG. 1 except that the planar shape of the needle-like portion 2a is different from the needle-like portion 2 of the strain sensor element of FIG. For this reason, the overlapping description of the strain sensor element of FIG. 6 is omitted.

  The needle-like part 2a of the strain sensor element has a fixing recess (notch) 4 at a side edge of a region overlapping with the detection part 1 in a plan view, and a side edge of a part extending from the detection part 1 A cutting recess (notch) 5 is provided in the part, a fixing through-hole 6 is provided in an area overlapping with the detection part 1, and cutting is performed at a position aligned in the width direction of the cutting recess 5 and the needle-like part 2a. A through hole 7 is provided.

  The strain sensor element is firmly fixed to the fabric by sewing a thread to the fabric through the fixing recess 4 and the fixing through-hole 6 in a state where the needle-like portion 2a is inserted into the fabric and temporarily fixed. Can do.

  In addition, the strain sensor element can be temporarily fixed more securely by engaging the fibers of the fabric with the fixing recess 4 when the needle-like portion 2a is inserted into the fabric.

  Furthermore, the strain sensor element is provided with the cutting recesses 5 and the cutting through-holes 7 arranged in a row in the width direction, so that the strain sensor element is relatively aligned along the row of the cutting recesses 5 and the cutting through-holes 7. The needle-like part 2a can be easily cut. For this reason, since the strain sensor element can be relatively easily cut off after the sharp tip of the needle-like portion 2a is fixed to the fabric, the safety of the motion detection device using the strain sensor element is improved. It can be improved.

  The lower limit of the opening width of the fixing recess 4 and the average diameter of the fixing through holes 6 is preferably 0.5 mm, and more preferably 0.7 mm. On the other hand, the upper limit of the opening width of the fixing recess 4 and the average diameter of the fixing through-hole 6 is preferably 2 mm, and more preferably 1.5 mm. When the opening width of the fixing recess 4 and the average diameter of the fixing through-hole 6 are less than the lower limit, it may be difficult to pass the sewing thread into the fixing recess 4 and the fixing through-hole 6. On the contrary, when the average diameter of the fixing recess 4 and the fixing through-hole 6 exceeds the upper limit, the width of the needle-like portion 2 may be unnecessarily increased, or the strength of the needle-like portion 2 may be insufficient. There is.

  On the other hand, the sizes of the cutting recess 5 and the cutting through hole 7 are not particularly limited, and may be set as appropriate in consideration of workability and ease of cutting the needle-like portion 2a. Moreover, you may bend | fold without cut | disconnecting the front-end | tip part of the needle-like part 2a using the recessed part 5 for a cutting | disconnection, and the through-hole 7 for a cutting | disconnection. That is, the cutting recess 5 and the cutting through-hole 7 can identify the position where the needle-like portion 2a is bent and can easily bend the needle-like portion 2a.

[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.

  The needle-like portion of the strain sensor element may have an outer shape such as a hook shape or a hook shape, for example, so as to prevent the strain sensor element from coming off. Further, the needle-like portion of the strain sensor element may be formed in a hook shape that can be engaged with another needle-like portion so that a plurality of the strain sensor elements can be connected.

  In the strain sensor element, the fixing concave portion, the fixing through hole, the cutting concave portion, and the cutting through hole of the needle-like portion can be individually omitted. Further, instead of the cutting recess and the cutting through hole, the thickness of the needle-like portion may be reduced to facilitate cutting. Moreover, you may provide these recessed parts and through-holes in the acicular part provided as a clamping member.

  The detection part of the said strain sensor element should just be what can output the change of expansion-contraction distortion as a change of electrical resistance, and is not limited to the thing using a carbon nanotube.

  The strain sensor element may include a thread-like (a diameter is not limited) as a detection unit. As such a thread-shaped detection unit, for example, a thread-shaped resistor in which the peripheral surface of a carbon nanotube bundle is coated with a resin composition can be used.

  Further, the needle-like portion of the strain sensor element may have a more complicated three-dimensional shape. As an example, when the detection unit is thread-like, the joint surface of the needle-like part with the detection unit may be, for example, a cylindrical surface in accordance with the detection unit. Further, the needle-like portion may have a caulking structure or the like, for example, for connection with the detection portion.

  The strain sensor element can be particularly suitably used for a motion detection device that detects the movement of a human body.

1,11,21 Detecting part 2,22,2a Needle-shaped part (electrode)
4 Fixing recess 5 Cutting recess 6 Fixing through hole 7 Cutting through hole 12 Electrodes 13 and 23 Needle-shaped portion (clamping member)
C fabric

Claims (5)

A strip-shaped or thread-shaped detection unit whose electrical resistance changes according to the strain in the longitudinal direction;
A strain sensor element comprising: a pair of needle-like parts disposed at both ends in the longitudinal direction of the detection part, the width of which gradually decreases toward the tip side.   The strain sensor element according to claim 1, wherein the pair of needle-like parts is a pair of electrodes connected to both ends of the detection part.   2. The strain sensor element according to claim 1, wherein the pair of needle-like portions are a pair of clamping members arranged to face a pair of electrodes connected to both ends of the detection portion.   The strain sensor element according to claim 1, 2 or 3, wherein a concave portion is provided on a side edge portion of the needle-like portion.   The strain sensor element according to any one of claims 1 to 4, wherein the needle-like portion has a through hole.

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