JP6701748B2 - Strain sensor element - Google Patents

Description

  The present invention relates to strain sensor elements.

  For example, in virtual reality technology used for games and the like, there is a demand for a motion detection device that detects the motion of the human body in order to reproduce the motion of the human body. Also, the use of the motion detection device is being considered for scientifically analyzing the motion of, for example, an athlete.

  As an example of the motion detecting device for detecting the movement of the human body, a tubular or supporter-like support body which is formed of a stretchable cloth and is fitted so as to fit around joints such as elbows, and the support body A belt-shaped strain sensor element which is attached so as to bridge between two points on both sides of the joint bending extension direction and both sides in the proximal and distal direction of the joint, and which is stretchable and includes a conductive elastomer capable of detecting the stretch amount thereof. A joint bending angle detecting device has been proposed (see Japanese Patent Laid-Open No. 1-136632).

  In the motion detection device described in the above publication, the strain sensor element is fixed to the support by sewing the strain sensor element or a member attached to the strain sensor element to the support formed of cloth. As described above, when the strain sensor element is sewn to the cloth, first, the strain sensor element cannot be easily attached to an accurate position without temporarily fixing the strain sensor element to the cloth using an adhesive agent or the like. . However, it is complicated to temporarily fix the strain sensor element.

JP-A-1-136632

  In view of the above-mentioned inconvenience, an object of the present invention is to provide a strain sensor element which is relatively easy to attach to a cloth.

  The invention made in order to solve the above-mentioned problems is a strip-shaped or thread-shaped detection part whose electric resistance changes in accordance with the strain in the longitudinal direction, and the detection part is arranged at both ends in the longitudinal direction, and the width thereof is the tip side. The strain sensor element includes a pair of needle-shaped portions that gradually decrease in length.

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

  The pair of needle-shaped parts may be a pair of electrodes connected to both ends of the detection part. As described above, since the pair of needle-shaped portions are the pair of electrodes connected to both ends of the detection portion, the number of components is not increased due to the needle-shaped portions, and the configurations of the strain sensor elements are compared. Can be simplified.

  The pair of needle-shaped portions may be a pair of sandwiching members arranged so as to face a pair of electrodes connected to both ends of the detection unit. In this way, the pair of needle-shaped portions is a pair of sandwiching members arranged so as to face the pair of electrodes connected to both ends of the detection unit, that is, the connection between the detection unit and the electrodes is more reliable. By making the pair of sandwiching members that can be provided in order to be needle-shaped portions, it is possible to relatively simplify the configuration of the strain sensor element without increasing the number of parts due to the needle-shaped portions.

  It is preferable that a side edge portion of the needle-shaped portion has a recess. As described above, since the side edge portion of the needle-shaped portion has the concave portion, the fibers of the cloth engage with the concave portion, so that the strain sensor can be more temporarily fixed and the cloth can be more easily attached. Become. Further, when the strain sensor element is fixed by sewing a thread on the cloth, the stitched thread engages with the concave portion, so that the strain sensor element is more reliably fixed.

  The needle-shaped portion may have a through hole. As described above, since the needle-shaped portion has the through hole, the thread can be sewn into the through hole to more securely fix the strain sensor element.

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

It is a schematic plan view showing a strain sensor element of one embodiment of the present invention. It is a typical side view of the strain sensor element of FIG. FIG. 2 is a schematic side view showing a temporarily fixed state of the strain sensor element of FIG. 1. 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 of 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 of 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 element according to the first embodiment of the present invention shown in FIG. 1 and FIG. And a pair of needle-shaped portions 2 whose width is gradually reduced toward the tip side.

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

<Detection unit>
The detection unit 1 may be any unit whose electric resistance changes according to expansion and contraction, but for example, a film-shaped detection body including a plurality of CNT fibers aligned in one direction can be used.

  The lower limit of the average width of the detection unit 1 (membrane-shaped detector) is preferably 0.3 mm, more preferably 0.5 mm. On the other hand, the upper limit of the average width of the detection unit 1 is preferably 10 mm, more preferably 5 mm, even more preferably 2 mm. If 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.

  The lower limit of the average thickness of the detection unit 1 is preferably 10 μm, more preferably 15 μm. On the other hand, the upper limit of the average thickness of the detection unit 1 is preferably 3 mm, more preferably 1 mm. If the average thickness of the detection unit 1 is less than the lower limit, the strength may be insufficient. On the other hand, when the average thickness of the detection unit 1 exceeds the upper limit, the detection unit 1 may buffer the needle-shaped portion 2 when inserting it into the cloth, and may hinder the 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, but can be, for example, 1 cm or more and 20 cm or less.

  In the detection unit 1, the average length in the longitudinal direction of the detection region, which is sandwiched between the pair of needle-shaped units 2 in plan view and substantially expands and contracts to change the electric resistance, is an object to be measured using the strain sensor element. It can be freely selected according to. The average length of the detection region may be, for example, 2 mm or more and 18 cm or less.

  The average length in the longitudinal direction of the fixed region of the detection unit 1 that overlaps with the pair of needle-shaped portions 2 in plan view and does not substantially contribute to the detection of strain depends on the attachment method of the needle-shaped portions 2 or the like. Although it is appropriately selected, it can be, for example, 3 mm or more and 5 cm or less.

  The lower limit of the electrical resistance (the value measured between the pair of needle-shaped portions 2) in the state where the detection unit 1 is not distorted is preferably 10Ω, and more preferably 100Ω. On the other hand, the upper limit of the electric resistance of the detection unit 1 in the absence of distortion is preferably 100 kΩ, and more preferably 10 kΩ. If the electrical resistance of the detection unit 1 in the absence of strain is less than the lower limit, the current for detecting elongation strain may increase and the power consumption of the strain sensor element may increase. On the contrary, when the electric resistance of the detection unit 1 in the absence of distortion exceeds the upper limit, the voltage of the detection circuit becomes high, which makes it difficult to reduce the size and power consumption of the device that processes the output of the distortion sensor element. May be

[Membrane detector]
The membranous detector has a layer formed of a plurality of CNT fibers that are aligned in one direction, and a film is formed by impregnating at least the surface layer (region near the surface) of the CNT fiber layer with an insulating elastomer described below. It is formed into a shape. Further, since the insulating elastomer hinders electrical contact between the CNT fibers, a region not impregnated with the insulating elastomer is left at the center of the layer of CNT fibers. Further, since the layer of CNT fibers is covered with the insulating elastomer by impregnation with the insulating elastomer, it is considered that a thin layer of the insulating elastomer is formed on the surface layer of the film-shaped detector.

  Such a film-shaped detector has elasticity due to the elastic force of the insulating elastomer and can expand and contract at least in the longitudinal direction. In this film-shaped detection body, the CNT fibers are separated from each other by extending at least in the longitudinal direction to increase the electric resistance, and the elastic contraction causes the CNT fibers to come into contact with each other again to reduce the electric resistance. In addition, in order to suppress the contact ratio between the CNT fibers and adjust the electric resistance, the film-shaped detector may include insulating fibers made of, for example, a synthetic resin in the layer of the CNT fibers.

  Since at least the surface layer of the film-shaped detection body is impregnated with the insulating elastomer, the CNT fiber bundle described later is covered with the insulating elastomer. Therefore, the insulating elastomer guides the expansion/contraction direction of the plurality of CNT fiber bundles. It also functions as a member. As a result, in the strain sensor element, the CNT fibers separated at the time of extension can be brought into contact with each other again at the same site at the time of contraction, and it is possible to prevent a decrease in expansion/contraction detection accuracy 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-shaped detector can be detected with higher accuracy.

  Further, in order to further facilitate the maintenance of such a contact relationship and the adjustment of stretchability, it is preferable that the back layer (region near the back surface) of the CNT fiber layer is also impregnated with an insulating elastomer. At this time, since the insulating elastomer is impregnated into at least a part of the surface layer of the CNT fiber layer, the bonding force between the CNT fiber layer and the insulating elastomer is also increased.

(CNT fiber)
The CNT fibers used in the film-shaped 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 connecting portion where the ends of the CNT single fiber are connected. The CNT single fibers are connected to each other in the longitudinal direction of these CNT single fibers. As described above, in the film-shaped detector, a layer having a large orientation length of the CNT fibers can be formed by connecting the CNT single fibers to each other in the longitudinal direction, and the length of the strain sensor element in the longitudinal direction can be reduced. It can be increased to improve sensitivity.

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

  Furthermore, the film-shaped 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, when the film-shaped detector is strained so as to be stretched in the expansion and contraction direction, the CNT fibers are cut and separated, and the CNT fiber bundle cutting space is provided. The resistance of the film-shaped detector 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, and 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 from each other. There will be both a gap and a gap. Further, since the surface layer of the plurality of CNT fiber bundles is covered with the insulating elastomer, the pressure in this gap is considered to be lower than the atmospheric pressure (negative pressure). Therefore, when the strain sensor element contracts ( When the strain is released), the contraction force of the gap urges the contraction of the strain sensor element. Further, since the friction between the CNT fibers is reduced within this gap, it is difficult to limit the movement of the CNT fibers.

  The layer of CNT fibers in the membranous detector may have a single-layer structure in which a plurality of CNT fibers or a plurality of CNT fiber bundles are arranged substantially parallel to each other in a plane, or may have a multi-layer structure. However, in order to secure a certain degree of conductivity, it is preferable to have a multilayer structure.

  As the CNT single fiber, either a single-wall single-wall nanotube (SWNT) or a multi-layer multi-wall nanotube (MWNT) can be used, but MWNT is preferable in terms of conductivity and heat capacity, and the diameter is 1. MWNTs of 5 nm or more and 100 nm or less are more preferable.

  The CNT monofilament can be produced by a known method, for example, a CVD (chemical vapor deposition) method, an arc method, a laser ablation method, a DIPS (direct injection pyrolysis synthesis) method, It can be manufactured by the CoMoCAT method (trademark) or the like. Among these, from the viewpoint that carbon nanotubes (MWNTs) of a desired size can be efficiently obtained, it is preferable to manufacture by a CVD method using iron as a catalyst and ethylene gas. In this case, an iron or nickel thin film serving as a catalyst is formed on a substrate such as a quartz glass substrate or a silicon substrate with an oxide film, and the carbon nanotubes of a desired length are grown by vertically aligned growth of the carbon nanotubes. Can be obtained.

(Insulating elastomer)
As described above, the insulating elastomer forms a layer that is impregnated in the CNT fiber layer and covers the surface of the CNT fiber layer, and has a function of imparting an elastic force to the strain sensor element. The layer of the insulating elastomer that covers one surface of the film-shaped detector is referred to as a substrate layer, and the layer of the insulating elastomer that covers the other surface of the film-shaped detector is referred to as a protective layer. As the insulating elastomer with which the CNT fiber layer of the film-shaped detector is impregnated, for example, rubber, styrene elastomer, olefin elastomer, vinyl chloride elastomer, urethane elastomer, amide elastomer, etc. 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), styrene/butadiene rubber (SBR). , Silicone rubber (Q), chloroprene rubber (CR), chlorosulphonated 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 them, natural rubber is preferable from the viewpoint of strength and the like.

  The insulating elastomer may be impregnated into the layer of CNT fibers by coating with an aqueous emulsion. The aqueous emulsion is an emulsion in which the main component of the dispersion medium is water. Since carbon nanotubes have high hydrophobicity, when an insulating elastomer is coated by coating with an aqueous emulsion, the insulating elastomer does not completely penetrate between a plurality of CNT fibers. That is, the insulating elastomer is partially impregnated between the plurality of CNT fibers, but the insulating elastomer does not impregnate the entire region in the cross section in the thickness direction of each CNT fiber. As a result, the insulating elastomer is prevented from completely impregnating between the plurality of CNT fibers to prevent the resistance change of the film-shaped detector from being affected, and the sensitivity to the strain of the film-shaped detector caused by the presence of the insulating elastomer. 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.

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

  The insulating elastomer preferably contains a coupling agent. When the insulating elastomer contains the coupling agent, the insulating elastomer and the CNT fiber can be crosslinked, and the bonding force between the insulating elastomer and the CNT fiber can be improved.

  Examples of the coupling agent that can be used include amino coupling agents such as amino silane coupling agents, amino titanium coupling agents, amino aluminum coupling agents, and silane coupling agents.

  Further, the insulating elastomer preferably contains a dispersant having adsorptivity for CNT fibers. Examples of the dispersant having such adsorptivity include those in which the adsorptive group portion has a salt structure (for example, alkyl ammonium salt), hydrophobic groups of CNT fiber (for example, alkyl chain, aromatic ring, etc.) Those having a hydrophilic group (for example, polyether) capable of interacting in the molecule 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 excellent in elasticity and durability as a material different from the insulating elastomer, the stretchability and durability of the strain sensor element can be enhanced. As the material different from the insulating elastomer, urethane resin is specifically preferable.

<Needle part>
The pair of needle-shaped portions 2 are used as terminals for connecting wirings for measuring the electric resistance of the detection unit 1, and are inserted into the cloth when the strain sensor element is fixed to the cloth, thereby the strain sensor. It is used to temporarily fix the device. That is, the strain sensor element is temporarily fixed to an accurate position by inserting the needle-shaped portion 2 into the cloth, and then permanently fixed to the cloth using, for example, a curable adhesive or the like.

  The electrical connection method between the needle-shaped portion 2 and the CNT fiber layer of the detection unit 1 is not particularly limited, but 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 of the CNT fiber layer where the carbon nanotubes are exposed (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 like portion 2) Examples thereof include a method in which a conductive adhesive or the like is spread so as to extend over the area, and a method in which the needle-shaped portion 2 is provided with a protrusion that is inserted into the detection portion 1 and reaches the layer of CNT fibers.

  Moreover, the needle-shaped part 2 can be fixed to the detection part 1 using an adhesive. Further, as this adhesive, for example, a pressure-sensitive adhesive, a curable adhesive, a thermoplastic adhesive or the like can be used. Examples of the pressure-sensitive adhesive include acrylic pressure-sensitive adhesives. Examples of the curable adhesive include epoxy adhesives. Further, if a conductive adhesive containing a conductive filler in a synthetic resin is used as the adhesive, the detection part 1 and the needle-shaped part 2 can be electrically and mechanically fixed at the same time.

  Further, by applying an adhesive on the end face in the longitudinal direction of the detection unit 1, the step between the needle-shaped unit 2 and the detection unit 1 can be made smooth, which allows the detection unit 1 to follow the needle-shaped unit 2. It becomes easy to insert the end of the into the cloth.

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

  The lower limit of the average thickness of the needle-shaped portion 2 is preferably 0.2 mm, more preferably 0.5 mm. On the other hand, the upper limit of the average thickness of the needle-shaped portion 2 is preferably 3 mm, more preferably 1 mm. If the average thickness of the needle-shaped portion 2 is less than the lower limit, the rigidity may be insufficient and it may be difficult to insert the needle-shaped portion 2 into the cloth. On the contrary, when the average thickness of the needle-shaped portion 2 exceeds the upper limit, it may be difficult to insert the end portion of the detection portion 1 between the fibers of the cloth.

  It is preferable that the average width of the portion of the needle-shaped portion 2 fixed to the detection portion 1 (usually the maximum width) is substantially equal to the average width of the detection portion 1. If the average width of the portion of the needle-shaped portion 2 fixed to the detection portion 1 is smaller than the average width of the detection portion 1, it may not be easy to insert the detection portion 1 into the cloth. If the average width of the portion of the needle-shaped portion 2 that is fixed to the detection unit 1 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 cloth.

  When the average width of the portion of the needle-shaped portion 2 fixed to the detection portion 1 is larger than the average width of the detection portion 1, the range of the average width of the portion of the needle-shaped portion 2 extending from the detection portion 1 is 0 mm or more. It is large and preferably 0.5 mm or less. When it exceeds the above range, as described above, it may be difficult to pull back the strain sensor element once it is inserted into the cloth. When the average width of the portion of the needle-shaped portion 2 that is fixed to the detection portion 1 is smaller than the average width of the detection portion 1, the detection portion 1 extending from the needle-shaped portion 2 is folded and inserted into or removed from the cloth. May be.

  As shown in the figure, the planar shape of the needle-shaped portion 2 may be bilaterally symmetric with respect to the longitudinal axis, or bilaterally asymmetric. Further, the needle-shaped 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 the detection portion 1 is not inserted into the cloth. You may. Further, the shape of the tip of the needle-shaped portion 2 may be such that it is thin enough to be inserted into the cloth to be used, and the tip may be rounded and chamfered. Further, the needle-shaped portion 2 may be formed so that not only its width but also its thickness is gradually reduced toward the distal end side, but by having a constant thickness, it is relatively easy to perform punching from a plate material or the like. Can be formed.

<Advantages>
Since the strain sensor element has a pair of needle-shaped portions 2 whose width is gradually reduced toward the tip end at both ends of the detection unit 1 which converts the expansion/contraction strain into a change in electric resistance, for example, as shown in FIG. By inserting the needle portion 2 into the cloth C, it is possible to temporarily fix the cloth C to the cloth C relatively easily. As described above, since the strain sensor element is relatively easy to attach to the cloth, the wearable device for detecting the movement of the human body can be easily manufactured by using the strain sensor element.

  Further, since the strain sensor element includes the needle-shaped portion 2 which is also an electrode, the strain-sensor element can be connected to the measurement circuit by inserting the needle-shaped portion 2 into the conductive wiring formed in advance on the cloth.

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

  In the present embodiment, the pair of needle-shaped portions 13 are a pair of sandwiching members that secure the connection between the detection portion 11 and the electrode 12 by sandwiching the detection portion 11 between the pair of electrodes 12.

  The detection unit 11 in the strain sensor element in FIG. 4 can be the same as the detection unit 1 in the strain sensor element in FIG. Therefore, redundant description of the detection unit 11 of the strain sensor element in FIG. 4 is omitted.

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

  The material of the pair of electrodes 12 is electrically conductive and does not substantially expand or contract during use of the strain sensor element. Note that “not substantially expand and contract” means that the expansion and contraction rate in the longitudinal direction of the electrode 12 relative to the expansion and contraction rate in the longitudinal direction during measurement using the strain sensor element in the detection region between the pair of electrodes 12 in the plan view of the detection unit 11. It means that the ratio of expansion/contraction ratio is 1/100 or less, preferably 1/1000 or less. In addition, the number of digits of the ratio of the expansion/contraction ratio of the expansion/contraction region 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 measurement, and is preferably larger by two or more digits. More preferable.

  The material forming 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. Further, the electrode 12 may be a laminated body including at least a conductive layer arranged on the outer surface and a reinforcing material layer imparting non-stretchability. Examples of the material of the metal foil include copper, aluminum, nickel, stainless steel and the like. Further, as the conductive cloth, a woven cloth or a non-woven cloth containing a fiber having conductivity on at least the surface can be used. Further, the surface of the electrode 12 may be covered with a material such as gold which is not easily corroded. Alternatively, the electrode 12 may be formed by coating the surface of the ceramic with gold or the like.

  The lower limit of the average thickness of the electrode 12 is preferably 10 μm, more preferably 50 μm. On the other hand, the upper limit of the average thickness of the electrode 12 is preferably 1 mm, more preferably 0.5 mm. If the average thickness of the electrode 12 is less than the lower limit, the electrode 12 may be broken due to bending or the like. On the contrary, when the average thickness of the electrode 12 exceeds the upper limit, the strain sensor element may be unnecessarily thick, or the needle-shaped portion 13 may be prevented from being inserted into the cloth.

  As a method of connecting the detection part 11 of the electrode 12 in the strain sensor element of FIG. 4 to the CNT fiber layer, a method of connecting the detection part 1 of the needle-shaped part 2 in the strain sensor element of FIG. It can be similar.

<Needle part>
The needle-shaped portion 13 in the strain sensor element of FIG. 4 is a sandwiching member that suppresses the deformation of the fixed region in which 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 electrode 12. is there. With such a configuration, the strain sensor element improves the detection accuracy by expanding and contracting only the detection region of the detection unit 11.

  Further, the needle-shaped portion 13 protrudes in the longitudinal direction from the detection portion 11 and the electrode 12 in a plan view, and the width of at least a part of this protruding portion is gradually reduced toward the tip side. Accordingly, the strain sensor element can be attached to the cloth relatively easily and accurately because the needle-shaped portion 13 can be inserted into the cloth and temporarily fixed.

  The needle 13 may be made of any material as long as it has sufficient rigidity, and may be conductive or insulating. Specifically, as the needle-shaped portion 13, for example, a resin composition containing polyimide, polyethylene terephthalate or the like as a main component, a metal such as nickel, stainless steel, copper or aluminum can be used.

  The average thickness of the needle-shaped 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-shaped portion 2, 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 in the strain sensor element can be the same.

  The electrode 12 and the needle-shaped portion 13 that face each other may be sandwiched by fastening members (not shown) such as bolts, rivets, and clamps. This fastening member may penetrate the detection unit 11, the electrode 12, and the needle-shaped portion 13, and may also serve as a member for electrically connecting the electrode 12 to the detection unit 11.

  The needle-shaped part 13 can be laminated on the detection part 11 by using, for example, an adhesive. As the 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 conductivity.

[Third embodiment]
The strain sensor element according to the first embodiment of the present invention shown in FIG. 5 is arranged at both ends in the longitudinal direction of the belt-shaped detector 21 whose electric resistance changes according to the strain in the longitudinal direction. The first needle-shaped portion 22 and the second needle-shaped portion 23 are provided so as to face the pair of needle-shaped portions 22 with the detection portion 21 interposed therebetween.

  In the present embodiment, the pair of first needle-shaped portions 22 are electrodes for measuring the electrical resistance of the detection unit 21, and the pair of second needle-shaped portions 23 are between the pair of first needle-shaped portions. By sandwiching the detection unit 21 in the region, the stretchable region of the detection unit 21 is accurately determined, and the sandwiching member improves the detection accuracy of the stretching strain by the strain sensor element.

  The detection unit 21 and the first needle-shaped portion 22 in the strain sensor element in FIG. 5 can be the same as the detection unit 1 and the needle-shaped portion 2 in the strain sensor element in FIG. Further, the second needle-shaped portion 23 in the strain sensor element of FIG. 5 can be the same as the needle-shaped portion 13 in the strain sensor element of FIG. Therefore, redundant description of the strain sensor element of FIG. 5 is omitted.

  In the strain sensor element, the first needle-shaped portion 22 and the second needle-shaped portion 23 that face each other function as one needle. When the thickness of the detection unit 21 is relatively large, the first needle-shaped portion 22 and the second needle-shaped portion 23 are configured so as to be in close contact with each other by bending, or twisted with each other. It is preferable that they be integrated by engaging the notches.

  As described above, the strain sensor element has the first needle-shaped portion 22 that is the electrode and the second needle-shaped portion 23 that is the sandwiching member, so that the strain sensor element has a clear step difference such that the thickness is rapidly increased on the front and back sides. Since it is difficult to form, the detection unit 21 is less likely to be caught by the cloth when the first needle-shaped portion 22 and the second needle-shaped portion 23 are inserted into the cloth, so that the attachment to the cloth is easier.

[Fourth Embodiment]
The strain sensor element according to the fourth embodiment of the present invention shown in FIG. 6 is provided with a 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. And a needle-shaped 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-shaped portion 2a is different from the needle-shaped portion 2 of the strain sensor element of FIG. Therefore, duplicate description of the strain sensor element of FIG. 6 is omitted.

  The needle-shaped portion 2a of the strain sensor element has a fixing recess (notch) 4 in a side edge portion of a region overlapping with the detection unit 1 in a plan view, and a side edge of a portion extending from the detection unit 1. Has a cutting concave portion (notch) 5, a fixing through hole 6 inside a region overlapping the detecting portion 1, and the cutting concave portion 5 and the needle-shaped portion 2a are arranged at positions aligned in the width direction. It has a through hole 7.

  The strain sensor element is firmly fixed to the cloth by sewn a thread to the cloth through the fixing concave portion 4 and the fixing through hole 6 in a state where the needle-shaped portion 2a is pierced and temporarily fixed to the cloth. You can

  Further, when the needle-shaped portion 2a is inserted into the cloth, the strain sensor element can be more reliably temporarily fixed by engaging the fibers of the cloth with the fixing recesses 4.

  Further, in the strain sensor element, the cutting recesses 5 and the cutting through holes 7 are provided in a row in the width direction, so that the cutting recesses 5 and the cutting through holes 7 are relatively arranged along the row. The needle-shaped portion 2a can be easily cut. For this reason, after the strain sensor element is fixed to the cloth, the sharp tip portion of the needle-shaped portion 2a can be relatively easily cut off, and thus the safety of the motion detection device using the strain sensor element can be improved. 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, 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, more preferably 1.5 mm. If 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 through 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-shaped portion 2 may be unnecessarily increased, or the strength of the needle-shaped 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 appropriately set in consideration of workability and easiness of cutting the needle-shaped portion 2a. Further, the cutting recess 5 and the cutting through hole 7 may be used to bend the tip of the needle-shaped portion 2a without cutting. That is, the cutting concave portion 5 and the cutting through hole 7 can specify the position where the needle-shaped portion 2a is bent and facilitate the bending of the needle-shaped portion 2a.

[Other Embodiments]
The above embodiment does not limit the configuration of the present invention. Therefore, in the above-described embodiment, it is possible to omit, replace, or add the constituent elements of each part of the embodiment based on the description and technical common sense of the present specification, and all of them are construed as belonging to the scope of the present invention. Should be.

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

  In the strain sensor element, the fixing recess, the fixing through hole, the cutting recess, and the cutting through hole of the needle-shaped portion can be individually omitted. Further, instead of the cutting recess and the cutting through hole, the thickness of the needle-shaped portion may be reduced to facilitate cutting. Further, these recesses and through holes may be provided in the needle-shaped portion provided as the holding member.

  The detection unit of the strain sensor element is not limited to the one using carbon nanotubes as long as it can output a change in expansion/contraction strain as a change in electric resistance.

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

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

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

1,11,21 Detection part 2,22,2a Needle part (electrode)
4 Fixing Recesses 5 Cutting Recesses 6 Fixing Through Holes 7 Cutting Through Holes 12 Electrodes 13, 23 Needle-shaped Parts (Holding Members)
C cloth

Claims (5)

A strip-shaped or thread-shaped detection unit that expands and contracts in the longitudinal direction and whose electric resistance changes according to the expansion and contraction ,
A pair of needle-shaped portions, which are respectively arranged at both ends in the longitudinal direction of the detection portion, and whose width gradually decreases toward the tip end side.   The strain sensor element according to claim 1, wherein the pair of needle-shaped portions are a pair of electrodes connected to both ends of the detection portion.   The strain sensor element according to claim 1, wherein the pair of needle-shaped portions are a pair of holding members arranged to face a pair of electrodes connected to both ends of the detection unit.   The strain sensor element according to claim 1, 2 or 3, wherein a concave portion is provided at a side edge portion of the needle-shaped portion.   The strain sensor element according to any one of claims 1 to 4, wherein the needle-shaped portion has a through hole.

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