JP7204089B2 - Tensile sensor and its manufacturing method - Google Patents

Description

The present invention relates to a tensile sensor and its manufacturing method.

Conventionally, a wide variety of tension sensors are known that are attached to an object to be detected and detect movement such as elongation of the object to be detected. Tensile sensors are being developed that are constructed as knitted or woven fabrics made from blended yarns interspersed with conductive fibers.

The tension sensor disclosed in Patent Document 1 allows a knitted or woven fabric configured to include a plurality of conductive threads to be stretchable in one direction, and allows the conductive threads to be stretched to maintain an insulated state. It is intended to detect the change in capacitance from the accompanying change in spacing. According to such a tension sensor, since the expansion and contraction of the knitted or woven fabric is detected as capacitance, no current flows even if a voltage is applied to the conductive yarn, and the power consumption in this part can be reduced to zero. , power consumption can be reduced.

JP 2012-177565 A

However, the tensile sensor disclosed in the above-mentioned Patent Document 1 is configured only as a woven or knitted fabric. There is a problem that it is difficult to accurately detect the deformation state of the object to be detected, the presence or absence of the acting tensile force, and the value of the tensile force.

Also, for example, when a tension sensor is installed on a detection target to detect deformation of the detection target, if some other dielectric or conductor comes close to the tension sensor, noise based on the proximity of the dielectric or conductor There is also the problem that the signal is mixed with the signal related to the deformation of the object to be detected, which is originally intended to be acquired, and it is difficult to detect the movement of the object to be detected, such as elongation, with high accuracy.

The present invention has been made to solve such problems, and provides a high-precision tension sensor whose detection accuracy is unlikely to decrease even if it is used continuously, and which is less susceptible to noise. The object is to provide a manufacturing method.

The above-mentioned object of the present invention is to provide a strip-shaped conductor having a stretchable dielectric layer, and stretchable first and second conductive layers provided on one side and the other side of the dielectric layer, respectively. A sensor body is provided, the first conductive layer includes a strip-shaped first electrode portion formed of a conductive thread including a metal plating thread or a metal wire, the dielectric layer is a high melting point resin layer, A first low melting point resin layer and a second low melting point resin layer are provided on both sides of the high melting point resin layer, and the first electrode part is impregnated with at least a part of the first low melting point resin layer. This is achieved by a tensile sensor that is positioned in a vertical direction and is capable of detecting changes in capacitance between the first conductive layer and the second conductive layer that accompany expansion and contraction.

In this tensile sensor, the melting point of the high melting point resin layer is preferably 40° C. or more higher than the melting points of the first low melting point resin layer and the second low melting point resin layer.

In addition, the second conductive layer includes a strip-shaped second electrode portion formed of a conductive thread, and the second electrode portion is located at a position facing the first electrode portion with the dielectric layer interposed therebetween. WHEREIN: It is preferable that at least one part of the said 2nd low melting point resin layer is impregnated and arrange|positioned.

Further, one surface side of the sensor main body may be provided with a stretchable base fabric laminated and arranged, and the stretchable base fabric may be configured to have stretch anisotropy.

Further, one surface side of the sensor main body is provided with a tubular stretchable base fabric laminated and arranged, and the longitudinal direction of the sensor main body is along the circumferential direction of the tubular stretchable base fabric. It further comprises a band-shaped stretch adjustment layer disposed along the circumferential direction of the tubular stretchable base fabric, wherein one end of the stretch adjustment layer is at least in the vicinity of one end of the sensor main body. The other end of the expansion/contraction adjusting layer is arranged at least near the other end of the sensor body, and the sensor main body and the expansion/contraction adjusting layer are arranged on a tubular elastic base fabric to form an annular structure. may be configured.

Moreover, it is preferable that the expansion/contraction adjusting layer is formed including the same material as the high-melting-point resin layer.

In addition, the above object of the present invention provides a metal plating thread on one side and the other side of an elastic dielectric layer having a high melting point resin layer and a low melting point resin layer provided on both sides of the high melting point resin layer, respectively. Alternatively, a first conductive layer having a belt-like first electrode portion formed of conductive yarn including metal wires and configured as a knitted fabric structure or a woven fabric structure, and a conductive yarn including metal-plated yarn or metal wires a lamination step of respectively arranging a second conductive layer configured as a knitted fabric structure or a woven fabric structure provided with a strip-shaped second electrode portion, a heating step of heating the low melting point resin layer to make it flowable; The first conductive layer and the second conductive layer are pressed so as to be close to each other, and the first conductive layer and the second conductive layer are impregnated with the low-melting-point resin layer in a flowable state. This is achieved by a method of manufacturing a tension sensor, including a pressing step of narrowing the inter-surface distance between the electrode portion and the second electrode portion.

Moreover, in this method of manufacturing a tension sensor, it is preferable that the pressing step holds the first conductive layer and the second conductive layer against each other through the high-melting-point resin layer in a non-flowing state.

ADVANTAGE OF THE INVENTION According to this invention, even if it continues using, the detection accuracy is hard to fall, and it can provide the high-precision tension sensor which is hard to be influenced by a noise, and its manufacturing method.

(a) is a schematic configuration plan view showing a tension sensor according to the present invention, and (b) is a schematic configuration rear view thereof. FIG. 2 is a schematic configuration cross-sectional view showing the AA cross section in FIG. 1(a); FIG. 3 is a schematic configuration cross-sectional view for explaining the structure of a dielectric layer in FIG. 2; 1 shows an example of a cross section of a knitted fabric of a first electrode part and a second electrode part provided in a tension sensor according to the present invention, where (a) is when not stretched and (b) is when stretched. It is a block diagram for explaining a method of manufacturing a tensile sensor according to the present invention. It is a schematic structure sectional drawing which shows the modification of the tension sensor which concerns on this invention. (a) is a schematic configuration perspective view showing a modification of the tension sensor according to the present invention, and (b) is a schematic configuration perspective view showing a configuration without an expansion/contraction adjustment layer of the modification. (a) is a schematic configuration plan view showing a modified example of the tension sensor according to the present invention, (b) is a schematic configuration cross-sectional view showing the A'-A' cross section, and (c) is a schematic configuration back view. be. It is a schematic structure sectional drawing which shows the modification of the tension sensor which concerns on this invention. It is a schematic structure sectional drawing which shows the modification of the tension sensor which concerns on this invention. (a) is a schematic configuration plan view of sample A of the tensile sensor according to the present invention, (b) is a schematic configuration cross-sectional view showing the A″-A″ cross section, and (c) is a schematic configuration back view. . 4 is a graph showing the relationship between the elongation rate of sample A and the value of detected capacitance. FIG. 10 is a schematic configuration cross-sectional view for explaining a sample C subjected to a noise influence confirmation test;

A tension sensor according to an embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the drawings are partially enlarged/reduced in order to facilitate understanding of the configuration. FIG. 1(a) is a schematic configuration plan view of a sensor main body 1a provided in a tension sensor 1 according to the present invention, and FIG. 1(b) is a schematic configuration rear view thereof. FIG. 2 is a schematic sectional view showing the AA section of FIG. 1(a). The sensor main body 1a provided in the tension sensor 1 according to the present invention constitutes a sensor that acquires, for example, respiratory information of a living body (for example, presence or absence of breathing, respiratory cycle, etc.) and body movement information (for example, information on limb movements). It is a sensor that can be used as a strain sensor that detects deformation of an object. As shown in FIGS. 1 and 2, the sensor main body 1a has a strip-like shape in plan view, and is provided on the dielectric layer 2 and on one side and the other side of the dielectric layer 2, respectively. It comprises a first conductive layer 3 and a second conductive layer 4 . This sensor main body 1a constitutes a capacitor with a dielectric layer 2 and a first conductive layer 3 and a second conductive layer 4 with the dielectric layer 2 interposed therebetween. 3 and the second conductive layer 4 is a sensor capable of detecting a change in capacitance.

The dielectric layer 2 is configured to have elasticity, and as shown in the cross-sectional view of FIG. It is configured to include a sheet-like first low-melting-point resin layer 22 and a second low-melting-point resin layer 23 . Further, the dielectric layer 2 is configured to have insulating properties so as not to conduct electricity between the first conductive layer 3 and the second conductive layer 4 even when they are laminated. The electric resistivity of the dielectric layer 2 is preferably 10 ⁶ Ω·cm or more and 10 ¹⁸ Ω·cm or less.

A thermoplastic elastomer can be exemplified as the material of the high melting point resin layer 21 . In particular, urethane rubber, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, butyl rubber, nitrile rubber, ethylene-propylene rubber, chloroprene rubber, acrylic rubber, chlorosulfonated polyethylene rubber, silicone rubber, fluororubber, ethylene-acetic acid Various rubber materials such as vinyl rubber and epichlorohydrin rubber can be used. Additives may also be added to the above materials. For example, dielectric constant adjustment, softening plasticizers, elongation enhancing additives, and the like can be mentioned. In addition, it is necessary to select a material that does not cause dielectric breakdown of the dielectric layer 2 as the additive. The high-melting-point resin layer 21 preferably has a melting point of 150°C or higher, more preferably 180°C or higher, and more preferably 200°C or higher. preferable.

As materials for the first and second low melting point resin layers 22 and 23, the materials exemplified in the material for the high melting point resin layer 21 can be used. For the first and second low-melting-point resin layers 22 and 23, those having a melting point of 110° or more can be preferably used, and those having a melting point of 120° or more are more preferable. Here, the first and second low-melting-point resin layers 22 and 23 and the high-melting-point resin layer 21 are formed using thermoplastic elastomers included in the same category, for example, both are formed from polyurethane rubber. can do. Moreover, as the high-melting-point resin layer 21, it is preferable to use a layer whose melting point is higher than the melting points of the first and second low-melting-point resin layers 22 and 23 by 40° C. or more. Moreover, it is more preferable to use one having a temperature higher than 60°C, and still more preferably one having a temperature higher than 80°C.

Further, as the material for forming the high-melting-point resin layer 21, for example, a high-melting-point foamed urethane rubber may be employed, and the dielectric layer 2 may be configured as a sponge having minute voids therein. Such a spongy structure allows the dielectric layer 2 to easily return to its initial shape (the shape before being stretched) when the tension is released.

Here, the thickness of the high-melting-point resin layer 21 is not particularly limited, but is preferably set in the range of 5 μm to 100 μm, more preferably set in the range of 10 μm to 75 μm. Furthermore, it is more preferable to set the thickness in the range of 20 μm to 60 μm. The thicknesses of the first low melting point resin layer 22 and the second low melting point resin layer 23 are also not particularly limited, but it is preferable to configure them so as to have a thickness approximately equal to the thickness of the high melting point resin layer 21 described above.

As shown in FIGS. 1 and 2, the first conductive layer 3 includes a strip-shaped first electrode portion 31 and strip-shaped first non-conductive portions 32 on both sides of the first electrode portion 31. there is The second conductive layer 4 has the same structure as the first conductive layer 3, and includes a strip-shaped second electrode portion 41, and strip-shaped second non-conductive portions 42 on both sides of the second electrode portion 41. configured with. The longitudinal direction of the first electrode portion 31 and the first non-conductive portion 32 of the first conductive layer 3 and the longitudinal direction of the second electrode portion 41 and the second non-conductive portion 42 of the second conductive layer 4 are The direction is set along the longitudinal direction of the strip-shaped sensor main body. Further, the extending direction of the strip-shaped sensor main body is not particularly limited, but the sensor main body may be configured to be extendable along the longitudinal direction.

One side of the first conductive layer 3 and the second conductive layer 4 is embedded in the first low-melting resin layer 22 and the second low-melting resin layer 23 included in the dielectric layer 2, as shown in FIG. placed in a state. That is, the first electrode portion 31 is arranged in a state in which at least a portion of the first low melting point resin layer 22 is impregnated, and the second electrode portion 41 is arranged such that at least a portion of the second low melting point resin layer 23 is impregnated with Arranged impregnated. Due to such a positional relationship, the first conductive layer 3 and the second conductive layer 4 are substantially arranged opposite to each other on both sides of the dielectric layer 2 with the high-melting-point resin layer 21 interposed therebetween. will have.

In addition, the first conductive layer 3 is configured to have stretchability. It is preferable to construct the fabric as a knitted or woven fabric (knitted and woven fabric) using a conductive thread. The same is true for the second conductive layer 4, and knitting or weaving using a conductive thread for forming the second electrode portion 41 and a non-conductive thread for forming each second non-conductive portion 42 is performed. It is preferably configured as a woven fabric. In this embodiment, the first conductive layer 3 (the first electrode portion 31 and the first non-conductive portion 32) and the second conductive layer 4 (the second electrode portion 41 and a second non-conductive portion 42) are formed. The knitted fabric structure is not particularly limited. Various knitted fabric structures can be employed. In addition, when the first conductive layer 3 and the second conductive layer 4 are formed of a woven fabric, examples of the woven structure include plain weave, twill weave, and satin weave. The method of manufacturing the first conductive layer 3 and the second conductive layer 4 is not limited to the above method. For example, after knitting or weaving the main body of the fabric with non-conductive fibers, conductive yarn is woven into a predetermined portion. Alternatively, the first electrode portion 31 (or the second electrode portion 41) can be formed and manufactured by embroidery or the like.

Here, as the conductive thread for forming the first electrode portion 31 and the second electrode portion 41, for example, a synthetic fiber (for example, polyester fiber, nylon fiber, etc.) or natural fiber is used as a core, and the core is A metal-coated thread (plated thread) coated with a metal component by performing wet or dry coating, plating, vacuum film formation, or other suitable coating method can be used. Although it is possible to use monofilaments for the core, multifilaments and spun yarns, which are aggregates of a plurality of single fibers, are preferable to monofilaments, and also wooly processed yarns and covering yarns such as SCY and DCY. A bulky textured yarn such as a fuzzed yarn is more preferred. Metal components to be coated on the core include, for example, pure metals such as aluminum, nickel, copper, titanium, magnesium, tin, zinc, iron, silver, gold, platinum, vanadium, molybdenum, tungsten, cobalt, alloys thereof, and stainless steel. , brass, etc. can be used. In addition, as the conductive thread, for example, pure metals such as aluminum, nickel, copper, titanium, magnesium, tin, zinc, iron, silver, gold, platinum, vanadium, molybdenum, tungsten, cobalt, alloys thereof, stainless steel, A thread-like or strip-like metal wire made of brass or the like, or a thread made of conductive fiber such as carbon fiber can be used. Also, a covering yarn obtained by winding a metal fiber around a synthetic fiber or natural fiber as a core may be used as the conductive thread.

The thickness of the conductive thread is not particularly limited, but the wire diameter per single wire is preferably 10 to 100 μm, for example. Among them, a thickness of 10 to 50 μm is particularly preferable because the flexibility and durability of the first conductive layer 3 and the second conductive layer 4 themselves (the first electrode portion 31 and the second electrode portion 41 themselves) can easily be compatible.

Moreover, when a metal wire is used as the conductive thread, its surface may be covered with an insulating coating layer. The metal wire coated with the insulating coating layer may be a monofilament or a multifilament, and preferably 2 to 9 wires, more preferably 3 to 7 wires are bundled and used as one thread. By covering the metal wire with the insulating coating layer in this way, the change in resistance when the tension sensor 1 expands and contracts becomes small, and it becomes possible to accurately detect the change in capacitance accompanying expansion and contraction. In addition, it is possible to obtain the tensile sensor 1 that is improved in waterproofness and durability and that can be used for a long period of time.

Specific names of materials that can be used as the insulating coating layer are too numerous to enumerate, but one example is as follows. That is, polyurethane, polyvinyl chloride, polypropylene, polyethylene, nylon (nylon 6, nylon 66, etc.) is a general term for polyamide-based synthetic fibers made by spinning long continuous chain-like synthetic polymers with amide bonds. ), polyester, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyetheretherketone, PFA, PVDF, fluorine-based resins such as ETFE, polystyrene, polycarbonate, polysulfone, polyethersulfone, formal (polyvinyl formal), butyral (polyvinyl butyral), etc. Materials that can be used as the insulating coating layer are not limited to these resin types. A metal wire coated with resin as an example is also called an enamel-coated metal wire.

As a method for coating the metal wire with the insulating coating layer, a general coating method from application of the molten material to drying may be adopted. In addition, a metal wire is used as a core material, and a fibrous (thread-like) insulating coating material (for example, yarn or cotton thread formed from the material that can be used as the insulating coating layer) is used as a cover material, and a covering thread (SCY or DCY) is used. It is also possible to adopt a method of forming the covering yarn, a method of heating and melting the covering yarn to form a coating film, and the like.

In addition, in the conductive yarn covered with the insulating coating layer, the material forming the insulating coating layer melts at the melting temperature of solder (approximately 170 ° C. to 250 ° C.), and has flexibility and stretchability. recommended. That is, it is preferable to use a thermoplastic resin having a melting point equal to or lower than the melting temperature of solder for the insulating coating layer. Soldering can be done in a short period of time, and the melted insulating coating layer does not burn out or shrink without obstructing the soldered part. It can be said that one having a melting point in a low temperature range ("150° C. or less" can be cited as an example of a standard) is suitable.

Here, the melting point is not the only condition for selecting the insulating coating layer, and the thickness of the insulating coating layer covering the conductive thread is also one of the conditions. For example, even if the melting point of the insulating coating layer is high (meaning a temperature exceeding 150°C as a guideline), if the coating thickness is thin, it will melt relatively easily during soldering. , can be used as an insulating coating layer.

In the above description, 150° C. is given as an example of the melting temperature of the solder, but this melting temperature varies depending on the resin selected for the insulating coating layer. For example, it should be 155° C. for polyester, modified polyester, polyester-nylon, etc., 105° C. for formal, 130° C. for polyurethane, 180° C. for polyesterimide, and so on.

In addition, the first electrode portion 31 and the second electrode portion 41 may be configured by using a stretchable thread mixed with the conductive thread. By using the stretchable thread mixedly, the stretchability of the first electrode portion 31 and the second electrode portion 41 can be improved. Also, the elastic yarn is preferably a non-conductive yarn. The elastic thread may be made of polyurethane or rubber-based elastomer material alone, or a covering thread that uses polyurethane or rubber-based elastomer material for the "core" and nylon or polyester for the "cover". can be adopted. By adopting such a covering yarn, functions such as hydrophilicity, water repellency, corrosion resistance/corrosion resistance, and coloring can be imparted. It is also useful for improving touch and controlling elongation.

Here, from the viewpoint of accurately detecting changes in capacitance, the first electrode portion 31 has a resistance change rate (%) of the electrical resistance value at 50% elongation with respect to the electrical resistance value at 0% elongation. It is preferably configured to be 20% or less, more preferably 10% or less. Furthermore, it is more preferable to configure so as to be 5% or less. Similarly, the second electrode portion 41 is preferably configured so that the resistance change rate of the electrical resistance value at 50% elongation with respect to the electrical resistance value at 0% elongation is 20% or less, and 10% or less. It is more preferable to configure Furthermore, it is more preferable to configure so as to be 5% or less. Here, the resistance change rate (%) is [(electrical resistance value at 50% elongation rate) - (electrical resistance value at 0% elongation rate)] / (electrical resistance value at 0% elongation rate) x 100% calculated as

Further, for the first electrode portion 31 and the second electrode portion 41, in order to suppress the resistance change rate (%) of the electrical resistance value at 50% elongation with respect to the electrical resistance value at 0% elongation, FIG. A knitted fabric structure as shown in (b) can also be adopted. The knitted fabric structure shown in FIGS. 4(a) and 4(b) is smooth knitting (also called double-sided knitting or interlock), and it seems that two layers of milling knitting are overlapped to fill the uneven grooves of each other. It is a knitted structure, and is composed of a conductive thread 10 and an elastic thread 11 . As long as the conductive thread 10 and the stretchable thread 11 are included, it is optional to mix other types of threads. 4A is the front side of the knitted fabric and the lower side is the back side of the knitted fabric, the conductive yarn 10 is entwined with the conductive yarn old loop 10a on the front side of the knitted fabric to form the first loop. P1 is formed and transferred to the back side of the knitted fabric. Then, the second loop P2 is formed by entwining the conductive yarn old loop 10b on the back side of the knitted fabric, the third loop P3 is formed on the front side of the knitted fabric, and the fourth loop P4 is formed on the back side of the knitted fabric. Repeat what you do. Therefore, the conductive yarn 10 is arranged in a zigzag pattern in the front-to-back direction in the knitted fabric.

On the other hand, the elastic yarn 11 is entwined with the elastic yarn old loop 11a on the back side of the knitted fabric to form the first loop R1, and moves to the front side of the knitted fabric. Then, a second loop R2 is formed by entwining with the elastic yarn old loop 11b on the front side of the knitted fabric, a third loop R3 is formed on the back side of the knitted fabric, and a fourth loop R4 is formed on the front side of the knitted fabric. Repeat to form. Accordingly, the elastic yarns 11 are also arranged in a zigzag pattern in the front-to-back direction in the knitted fabric. As a result, the cross portions 13 of the conductive yarn 10 and the elastic yarn 11 are alternately arranged for each loop in the knitted fabric.

Here, the stretchable thread 11 has abundant stretchability, whereas the conductive thread 10 hardly stretches. Therefore, when the knitted fabric structure is stretched along the surface direction of its front and back surfaces (horizontal direction in FIG. 4), the stretchable yarns 11 intersect the conductive yarns 10 in the cross portion 13, thereby stretching the front and back surfaces of the knitted fabric. The cross angle .theta. generated on the side is gradually increased, and after passing through a situation where the angle becomes obtuse, only the stretchable thread 11 gradually stretches well. Next, a behavior occurs in which the conductive thread 10 is let out from the loop to the cloth portion 13 as if being pulled by the stretching of the stretchable thread 11 . In addition, when the stretch is released, only the stretchable yarn 11 in the cross portion 13 generates a tightening force due to contraction, and the conductive yarn 10 receives this tightening force and pushes from the cross portion 13 into the loops on both outer sides thereof. . The tightening force of the stretchable yarn 11 at this time exerts an effect of maintaining the zigzag arrangement of the conductive yarn 10 in the non-stretchable knitted fabric structure.

In this way, the conductive yarn 10 expands and contracts together with the expansion and contraction of the stretchable yarn 11 while only making the loop smaller or larger by feeding or pushing from the loop to the cross portion 13. The knitted fabric structure has elasticity as shown in FIG. 4(b). As is clear from this description, the conductive thread 10 does not substantially expand and contract, so the total length used in the course direction does not change, and the outer diameter does not change. In addition, the loops of the conductive yarn 10 arranged in the direction of the course do not contact each other, and there is no tangling or contact between a plurality of courses, and the electrical resistance remains unchanged.

In addition, the first electrode portion 31 is preferably configured so that the electrical resistance value per unit length (1 cm) at 0% elongation is 50 Ω or less, and more preferably 10 Ω or less. . Furthermore, it is more preferable to configure the resistance to be 5Ω or less. Similarly, the second electrode portion 41 is preferably configured so that the electrical resistance value per unit length (1 cm) at 0% elongation is 50 Ω or less, more preferably 10 Ω or less. preferable. Furthermore, it is more preferable to configure the resistance to be 5Ω or less.

Further, the first electrode portion 31 may be configured to have anisotropic expansion and contraction. In other words, the first electrode portion 31 may be configured to have a characteristic of being easily elongated in its longitudinal direction and being difficult to be elongated in its lateral direction. In this way, when the dimensional change in the lateral direction of the first electrode part 31 due to elongation is smaller than that in the longitudinal direction, when the first electrode part 31 is elongated in the longitudinal direction by 50%, It is preferable that the dimensional change rate in the transverse direction (the rate of change in the transverse direction dimension at 0% elongation) is less than 5%. Such a configuration can be obtained, for example, by forming the first electrode portion 31 as a double knitted fabric. The double knitted fabric refers to knitted fabrics such as milling, pearl knitting, and smooth knitting. Since the double knitted fabric has a zigzag accordion structure in its thickness direction, the accordion structure effectively suppresses the dimensional change in the lateral direction of the first electrode portion 31 during expansion and contraction. Similarly, the second electrode portion 41 may be configured to have anisotropic expansion and contraction.

Synthetic fibers (for example, polyester fibers, nylon fibers, etc.), natural fibers, and synthetic fibers and stretchable threads are used as non-conductive threads for forming the first non-conductive part 32 and the second non-conductive part 42. materials, etc., can be used. By using the stretchable thread mixedly, the stretchability of the first non-conductive portion 32 and the second non-conductive portion 42 can be improved. For the elastic thread, for example, polyurethane or rubber-based elastomer material may be used alone, or covering thread using polyurethane or rubber-based elastomer material for the "core" and nylon or polyester for the "cover". etc. can be adopted. By adopting such a covering yarn, functions such as hydrophilicity, water repellency, corrosion resistance/corrosion resistance, and coloring can be imparted. It is also useful for improving touch and controlling elongation. Monofilaments can also be used as non-conductive yarns, but multifilaments and spun yarns, which are aggregates of a plurality of single fibers, can be preferably used rather than monofilaments.

Moreover, the first non-conductive portion 32 and the second non-conductive portion 42 are preferably formed of a non-conductive thread having heat resistance against the melting temperature of solder. Here, the heat resistance required for the non-conductive thread forming the first non-conductive portion 32 and the second non-conductive portion 42 is such that it can ignite or melt even when it comes into contact with molten solder (or a soldering iron in a heated state). It does not cause damage and is not easily burnt down. However, the degree of scorching is within the permissible range (can be used for forming non-conductive portions). In other words, as long as it has heat resistance to such an extent that its shape remains even after soldering, it is sufficient as a function. In order to assist the action of preventing the melted solder from penetrating into the first non-conductive portion 32 and the second non-conductive portion 42, the knitting structure of the first non-conductive portion 32 and the second non-conductive portion 42 is made dense. It is even more preferable to add countermeasures. The heat resistance required for the first non-conductive portion 32 and the second non-conductive portion 42 is required at the contact position with the first electrode portion 31 and the second electrode portion 41. The entire band width direction of the first non-conductive portion 32 and the second non-conductive portion 42 need not necessarily have the same configuration. For example, regarding the first non-conductive portion 32, only one course or several courses in contact with the first electrode portion 31 are provided with heat resistance, and a course portion (non-conductive portion) not in direct contact with the first electrode portion 31 is provided with heat resistance. central part in the band width direction, etc.) can be knitted using a general knitting structure or a general material (one that does not have heat resistance to molten solder). The same applies to the second non-conductive portion 42 as well.

Specific examples of heat-resistant non-conductive yarns that are preferable for forming the first non-conductive portion 32 and the second non-conductive portion 42 include various natural fibers such as cotton and wool, glass fibers, ceramic fibers, and the like. fiber, carbon fiber, and various synthetic fibers (e.g. aramid fiber, phenolic fiber, PBO, polyarylate, polyimide, melamine, PPS, PEEK, PTFE, cellulose fiber (flame retardant), nylon (flame retardant) , acrylic fiber, etc.) and the like can be exemplified.

The operation of the tension sensor 1 having such a configuration will be described below. First, a voltage is applied to each of the first electrode portion 31 and the second electrode portion 41 included in the first conductive layer 3 and the second conductive layer 4, respectively. In this state, for example, when the tension sensor 1 (sensor main body 1a) is elongated in the longitudinal direction, the distance between the first electrode portion 31 and the second electrode portion 41 is reduced, and the first electrode portion 31 and the second electrode portion 41 are separated from each other. The capacitance between In addition, the extension also increases the area of the tension sensor 1, and the capacitance between the first electrode portion 31 and the second electrode portion 41 increases. Next, when the extension state is released and the tension sensor 1 contracts (the extension rate is 0%), the distance between the first electrode portion 31 and the second electrode portion 41 increases, and the tension sensor 1 (sensor main body 1a) expands. area is also reduced, the capacitance between the first electrode portion 31 and the second electrode portion 41 is reduced. That is, when the tensile sensor 1 detects the deformation of the object to be detected, if the detected capacitance increases, it can be detected that the deformation has increased. More specifically, for example, when the tension sensor 1 is attached to the elbow portion or knee portion of a jacket worn by a person, the bending of the arm or leg causes the tension sensor 1 to extend and detect static electricity. The capacitance value changes greatly. By detecting the capacitance value at this time, the movement of the elbows and knees of the human body can be clearly detected. Further, for example, by attaching the tension sensor 1 (sensor main body 1a) to the chest or abdomen of a jacket worn by a person, or by winding the tension sensor 1 (sensor body 1a) around the chest or waist. By attaching the main body 1a), the tension sensor 1 expands and contracts based on changes in the wearer's physique caused by breathing. or whether the breathing cycle is fast or slow.

Next, a method for manufacturing the tension sensor 1 according to the present invention will be described. As shown in the block diagram of FIG. 5, the method of manufacturing the tensile sensor 1 includes a dielectric layer forming step S1, a first conductive layer forming step S2, a second conductive layer forming step S3, a stacking step S4, a heating step S5, and a pressing step S6. For convenience of explanation, in the block diagram of FIG. 5, these steps are shown in the order of dielectric layer formation step S1, first conductive layer formation step S2, and second conductive layer formation step S3. However, steps S1 to S3 may be performed in any order as long as they are performed before the stacking step 4. For example, the dielectric layer forming step S1 may be performed after the first conductive layer forming step S2 and the second conductive layer forming step S3, or the dielectric layer forming step S1, the first conductive layer forming step S2, and the second conductive layer forming step S2. Each step of the conductive layer forming step S3 may be performed at the same time.

In the dielectric layer forming step S1, the high melting point resin layer 21 and the low melting point resin layers (the first low melting point resin layer 22 and the second low melting point resin layer 23) provided on both surfaces of the high melting point resin layer 21 are provided respectively. This is a step of forming a dielectric layer 2 having a property. The method of forming the dielectric layer 2 in this dielectric layer forming step S1 is not particularly limited. 22 and the second low-melting-point resin layer 23) may be laminated with an adhesive layer interposed (or by heat lamination without an adhesive layer interposed), or the film-like high-melting-point resin layer 21 may be formed. may be coated with a material for forming the low-melting-point resin layers 22 and 23 on both surfaces thereof, or three layers may be formed by extrusion molding. Alternatively, after laminating a film-like low-melting resin layer (for example, the first low-melting-point resin layer 22) on one surface of the film-like high-melting-point resin layer 21 with an adhesive layer interposed therebetween, the high-melting-point resin layer 21 is laminated. It may be formed by applying a material for forming the low melting point resin layer 23 on the other surface of the .

The first conductive layer forming step S2 and the second conductive layer forming step S3 are steps of forming the first conductive layer 3 and the second conductive layer 4 described above. The first conductive layer 3 and the The step of forming the second conductive layer 4 can be exemplified. Since the method for forming the first conductive layer 3 and the second conductive layer 4 has been described in detail above, the description thereof is omitted here.

In the stacking step S4, strip-like first electrode portions 31 made of the conductive thread formed in the first conductive layer forming step S2 are formed on one side and the other side of the dielectric layer 2 formed in the dielectric layer forming step S1. A first conductive layer 3 configured as a knitted fabric structure or a woven fabric structure, and a strip-shaped second electrode portion 41 made of a conductive yarn formed in the second conductive layer forming step S3. It is a step of respectively arranging the second conductive layer 4 configured as. More specifically, the first conductive layer 3 is laminated on the first low-melting resin layer 22 in the dielectric layer 2, and the second conductive layer 4 is laminated on the second low-melting resin layer 23 in the dielectric layer 2. is a step of laminating the

The heating step S5 is a step of heating the low melting point resin layers (the first low melting point resin layer 22 and the second low melting point resin layer 23) to make the low melting point resin layers 22 and 23 flowable. The heating temperature in the heating step S5 makes the low melting point resin layers (the first low melting point resin layer 22 and the second low melting point resin layer 23) included in the dielectric layer 2 flowable, but the high melting point resin layer 21 is set to a temperature that does not allow the For example, the temperature is set to a temperature that melts the low melting point resin layers (the first low melting point resin layer 22 and the second low melting point resin layer 23 ) but does not melt the high melting point resin layer 21 . Alternatively, the temperature may be set to a temperature that allows the low-melting-point resin layers (the first low-melting-point resin layer 22 and the second low-melting-point resin layer 23) to flow without being melted.

In the pressing step S6, the first conductive layer 3 and the second conductive layer 4 are pressed by a pressing device or the like so as to be close to each other, and a low melting point resin layer (first low melting point resin While impregnating the first conductive layer 3 and the second conductive layer 4 with the layer 22 and the second low melting point resin layer 23), the first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode This is the step of narrowing the face-to-face distance with the portion 41). The high-melting-point resin layer 21 included in the dielectric layer 2 is not melted by heating in the heating step S5 and is maintained in a non-fluid state. is pressed from both sides through the high-melting-point resin layer 21 in a non-flowing state so that the first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode portion 41) to be as narrow as possible.

After the pressing step S6 is completed, the laminate composed of the first conductive layer 3, the dielectric layer 2 and the second conductive layer 4 is naturally cooled, so that the low-melting resin layers 22 and 23 which have been in a flowable state are removed. is solidified, the first conductive layer 3 and the second conductive layer 4 are firmly fixed to the dielectric layer 2, and the tensile sensor 1 is completed. In the above method, a heat press method may be used so that the heating step S5 and the pressing step S6 are performed simultaneously.

As described above, the tensile sensor 1 of the present invention has a capacitance value based on a change in the area of the tensile sensor 1 in addition to a change in the interval between the first electrode portion 31 and the second electrode portion 41 due to expansion and contraction. , it is possible to improve the detection sensitivity for changes in capacitance. In addition, since the dielectric layer 2 having stretchability is provided between the first conductive layer 3 and the second conductive layer 4, the state from the stretched state to the state before stretched (state where the stretch rate is 0%) It has the characteristic of being easy to return to the original shape, and has the effect of not easily losing its stretchability even if it is repeatedly stretched and stretched during continuous use. Furthermore, since the dielectric layer 2 is interposed, the first conductive layer 3 and the second conductive layer 3 are so weak that the conductive threads forming the first electrode portion 31 and the second electrode portion 41 are broken. It is possible to effectively suppress the extension of 4 beyond the limit.

In the present invention, the dielectric layer 2 includes a sheet-like high-melting point resin layer 21, and sheet-like first low-melting point resin layers 22 and second low-melting point resin layers 22 and 22 provided on both sides of the high-melting point resin layer 21, respectively. The first low-melting-point resin layer 22 and the second low-melting-point resin layer 22 and the second low-melting-point resin layer 23 are melted and become fluid by the heating step S5 and the pressing step S6 in the manufacturing process. 23 is impregnated into the fabric of the first conductive layer 3 and the second conductive layer 4 (gap between stitches and fibers) and solidified, so that the first conductive layer 3 and the second conductive layer 4 are strongly dielectric. It will be fixed to layer 2. Further, since the high-melting-point resin layer 21 in the dielectric layer 2 does not melt and maintains a predetermined thickness (for example, 5 μm to 100 μm), a part of the first electrode portion 31 in the first conductive layer 3 and the second It is possible to reliably prevent a short circuit between the conductive layer 4 and a part of the second electrode portion 41 via the dielectric layer 2 (high melting point resin layer 21). Especially when the first conductive layer 3 and the second conductive layer 4 are configured as fabrics (knitted fabrics) knitted or woven using conductive yarns and non-conductive yarns, as in the present embodiment. In this case, a so-called fluffed portion of the fabric may occur, and this fluffed portion may pierce the dielectric layer 2 during the pressing step S6. By configuring the body layer 2, it is possible to reliably prevent the penetration of the fluffed portion. 2, the first electrode portion 31 provided in the first conductive layer 3 and the second electrode portion 41 provided in the second conductive layer 4 are substantially the same as the height provided in the dielectric layer 2, as shown in FIG. Only the thickness dimension of the melting point resin layer 21 (actually, the dimension obtained by adding the thickness dimension of the high melting point resin layer 21 and the slight thickness dimension of the first low melting point resin layer 22 and the second low melting point resin layer 23) It is possible to dispose the first electrode portion 31 and the electrode portion 41 in extremely close proximity to each other. As a result, the change in capacitance between the first conductive layer 3 and the second conductive layer 4 due to expansion and contraction of the tensile sensor 1 can be detected with high sensitivity. It is possible to reduce the ratio of noise signals mixed in the detection signal when some other dielectric material approaches the tensile sensor 1 when detecting deformation of the object to be detected, and is less susceptible to noise. A highly accurate tension sensor 1 can be obtained.

Further, when forming the high melting point resin layer 21 from a resin material having a melting point higher by 40° C. or more than the melting points of the first low melting point resin layer 22 and the second low melting point resin layer 23 provided in the dielectric layer 2, the manufacturing process Even if the heating temperature in the heating step S5 becomes higher than the set temperature for some reason, it is possible to effectively prevent the high melting point resin layer 21 from melting.

Further, in the tensile sensor 1 according to the present invention, the resistance change rate of the first electrode portion 31 when stretched by 50% is configured to be 20% or less. When configured so that the rate of change in resistance is 20% or less, it is possible to accurately capture the change in the detected capacitance. In addition, the electric resistance value per unit length (1 cm) of the first electrode portion 31 is configured to be 50 Ω or less, and similarly, the electric resistance value per unit length (1 cm) of the second electrode portion 41 is When configured so as to be 50Ω or less, it is possible to more accurately capture the change in the detected capacitance.

In addition, since the first electrode portion 31 and the second electrode portion 41 are configured to have a knitted fabric structure, the extension of the tension sensor 1 causes the conductive material forming the first electrode portion 31 and the second electrode portion 41 to expand. It is possible to provide a structure in which the elastic thread is difficult to break.

Here, the first electrode portion 31 and the second electrode portion 41 configured to have a knitted fabric structure are, for example, milled knitted, purl knitted, smooth knitted fabrics, etc., rather than a single knitted fabric such as plain knitting. A change in capacitance can be detected with even higher accuracy when configured as a double knitted fabric such as a knitted fabric. In the case of a double knitted fabric, a zigzag accordion structure is formed in the thickness direction. As a result of being able to make the area increase ratio of the portion 31 and the second electrode portion 41 substantially constant, it is possible to detect a change in capacitance with high accuracy.

Although the tensile sensor 1 according to one embodiment of the present invention has been described above, the specific configuration of the tensile sensor 1 is not limited to the above embodiment. For example, as shown in the schematic configuration plan view of FIG. 6, the tension sensor 1 may be configured to include a stretchable base fabric 5 laminated on one side of the sensor main body 1a. When adopting such a configuration, the sensor body 1a may be adhered onto the stretchable base cloth 5 via an adhesive layer, or the sensor body 1a may be sewn onto the stretchable base cloth 5 by sewing and fixed. You may The stretchable base fabric 5 is not particularly limited, but examples thereof include waistbands and supporters made of woven rubber, and stretchable fabrics for T-shirts and the like. Further, the stretchable base fabric 5 may be configured to have stretch anisotropy. When the stretchable base fabric 5 is configured to have stretch anisotropy, even if the sensor main body 1a has a structure that does not have stretch anisotropy, the tensile sensor 1 as a whole exhibits the properties of stretch anisotropy. It is possible to detect the change in capacitance with high precision and high sensitivity with respect to expansion and contraction.

Here, the first conductive layer 3 or the second conductive layer 4 and the stretchable base fabric are arranged so that the first conductive layer 3 or the second conductive layer 4 of the sensor main body 1a constitutes a part of the stretchable base fabric 5. 5 can also be integrated. More specifically, for example, when knitting the elastic base fabric 5 as a woven rubber structure, the first conductive layer 3 or the second conductive layer 4 is also incorporated and knitted, so that the first conductive layer 3 Alternatively, the second conductive layer 4 and the elastic base fabric 5 may be integrated.

Further, as shown in the schematic configuration perspective view of FIG. 7A, the elastic base cloth 5 is configured in a tubular shape, and the sensor main body 1a is arranged such that the longitudinal direction thereof is the circumferential direction of the tubular elastic base cloth 5. The tension sensor 1 may be configured by stacking and arranging so as to be in the direction along the . When the sensor body 1a is laminated on such a tubular stretchable base cloth 5, it is configured to further include a strip-shaped stretch adjustment layer 6 arranged along the circumferential direction of the tubular stretchable base cloth 5. You can also Here, one end of the expansion/contraction adjustment layer 6 is arranged at least near one end of the sensor body 1a, and the other end of the expansion/contraction adjustment layer 6 is arranged at least near the other end of the sensor body 1a. configured to In the configuration of FIG. 7A, one end of the expansion/contraction adjustment layer 6 is connected to one end of the long sensor body 1a, and the other end of the expansion/contraction adjustment layer 6 is connected to the other end of the sensor body 1a. is configured to By providing such a stretch adjustment layer 6, the sensor main body 1a and the stretch adjustment layer 6 constitute an integrated structure, and a ring structure is formed on the tubular stretch fabric 5. As shown in FIG. Moreover, the expansion/contraction adjusting layer 6 is preferably formed so as to contain the same material as the high melting point resin layer 21 described above, and more preferably formed from the same material as the high melting point resin layer 21 . Moreover, the thickness dimension of the expansion/contraction adjusting layer 6 is preferably configured to be the same as the thickness dimension of the high melting point resin layer 21 .

Here, for example, as shown in FIG. 7B, a tensile sensor 1 having a structure in which a sensor body 1a is simply laminated on a tubular stretchable base cloth 5 is wound around the chest or waist of a human body. In the case of detecting respiratory cycle information and the like based on changes in the wearer's physique due to breathing, the portion 5a that does not function as a sensor (region other than the sensor main body 1a) expands and contracts greatly due to physique changes due to breathing. On the other hand, the sensor main body 1a itself becomes difficult to expand and contract, and there is a possibility that respiratory cycle information cannot be detected efficiently. On the other hand, as shown in FIG. 7(a), a stretch adjusting layer 6 is arranged in a portion 5a of the stretchable base fabric 5 that does not function as a sensor, and the sensor main body 1a and the stretch adjusting layer 6 are integrated into an annular ring. By forming the structure, the sensor main body 1a also expands and contracts greatly according to changes in body size due to breathing, so that changes in capacitance due to changes in body size can be detected with high accuracy and high sensitivity. It is possible to efficiently detect respiratory cycle information and the like.

In addition, when the belt-like expansion/contraction adjustment layer 6 is provided, one end of the expansion/contraction adjustment layer 6 is necessarily connected to one end of the sensor main body 1a as shown in FIG. It is not necessary to connect the other end of the layer 6 to the other end of the sensor main body 1a. However, similarly, the other end of the expansion/contraction adjustment layer 6 may be arranged at a position forming a gap with the other end of the sensor main body 1a. Even with such a configuration, the sensor main body and the stretch adjustment layer, although discontinuous, can form a substantially annular structure on the tubular stretchable base fabric, so that the same effect as described above can be obtained. can be obtained.

Moreover, the band-like stretch adjustment layer 6 may be formed of the same material over the entire length thereof, or may be partially formed of a different material. As for the structure of the expansion/contraction adjustment layer 6, for example, a predetermined region adjacent to one end of the sensor body 1a and a predetermined region adjacent to the other end of the sensor main body 1a are configured as easily stretchable portions, and a difficultly stretchable portion is formed between the easily stretchable portions. may be arranged.

In the above embodiment, the first electrode portion 31 and the second electrode portion 41 are arranged along the longitudinal direction of the strip-shaped tensile sensor 1 (sensor main body 1a) as shown in FIGS. However, the specific form of the first electrode portion 31 and the second electrode portion 41 is not particularly limited. It can be configured in various forms such as an elongated wave shape and a zigzag shape.

Further, in the above-described embodiment, the first conductive layer 3 is configured to include the first non-conductive portion 32, but the first non-conductive portion 32 is omitted, and the first electrode portion 31 alone provides the first electrode. 1 conductive layer 3 may be configured. Similarly, the second conductive layer 4 may be composed only of the second electrode portion 41 .

Alternatively, a coating layer may be provided to cover the exposed surfaces of the first conductive layer 3 and the second conductive layer 4 (surfaces not in contact with the dielectric layer 2). By providing such a coating layer, the first electrode portion 31 and the second electrode portion 41 can be protected, and the durability of the tensile sensor 1 can be improved. The coating layer may be provided only on either the first conductive layer 3 side or the second conductive layer 4 side. As the material for forming the covering layer, for example, the material for forming the dielectric layer 2 described above can be used.

In the above embodiment, the first conductive layer 3 and the second conductive layer 4 are each provided with a single first electrode portion 31 and a plurality of second electrode portions 41, as shown in FIG. However, the numbers of the first electrode portions 31 and the second electrode portions 41 are not particularly limited. For example, as shown in FIGS. The tensile sensor 1 (sensor main body 1a) may be constructed by arranging a plurality of first electrode portions 31 and a plurality of second electrode portions 41 on both surface sides thereof. In the configuration shown in FIG. 8, the first electrode portions 31 are arranged parallel to each other with a predetermined spacing, and the second electrode portions 41 are similarly arranged parallel to each other with a predetermined spacing. are arranged so that A first non-conductive portion 32 is arranged between the first electrode portions 31 , and a second non-conductive portion 42 is arranged between the second electrode portions 41 . Moreover, when adopting such a configuration, it is preferable to arrange each first electrode portion 31 and each second electrode portion 41 at positions facing each other with the dielectric layer 2 interposed therebetween. 8(a) is a schematic configuration plan view of the tension sensor 1, and FIG. 8(b) is a schematic configuration cross-sectional view showing a section taken along line A'-A' of FIG. 8(a). Moreover, FIG.8(c) is a schematic structure back view.

Further, in the configuration shown in FIG. 8, in order to constitute an aggregate of the plurality of first electrode portions 31 as one electrode, the ends on one side of each first electrode portion 31 are short-circuited and each first electrode portion 31 is The ends of one electrode portion 31 on the other side may be short-circuited. may be configured by short-circuiting the ends on one side of each first electrode portion 31 and short-circuiting the ends on the other side of each first electrode portion 31 .

In the configuration shown in FIG. 8, each combination of the first electrode portions 31 and the second electrode portions 41 (the first electrode portion 31a and the second electrode portion 41a , a combination of the first electrode portion 31b and the second electrode portion 41b, and a combination of the first electrode portion 31c and the second electrode portion 41c) may be configured as independent capacitors. When adopting such a configuration, the tension sensor 1 (sensor main body 1a) can detect not only tension in the longitudinal direction, but also torsion about the longitudinal direction. Specifically, when the tensile sensor 1 (sensor main body 1a) is twisted with its longitudinal direction as an axis, the central portion of the tensile sensor 1 (sensor main body 1a) is larger than the side edge portions. Because of the deformation, the value of the capacitance change detected by the capacitor composed of the first electrode portion 31b and the second electrode portion 41b arranged in the center and the value of the change in capacitance detected by the first electrode portion 31a arranged on the side edge portion (31c) and the value of the capacitance change detected by the capacitor formed by the second electrode portion 41a (41c). By detecting this difference, it is possible to determine whether or not the tensile sensor 1 (sensor main body 1a) is twisted.

Further, in the above-described embodiment, the first electrode portion 31 and the second electrode portion 41 are configured to have the same width (the dimension in the direction perpendicular to the longitudinal direction). is not particularly limited to For example, as shown in the schematic configuration cross-sectional view of FIG. The second electrode portion 41 may be arranged at a position facing the first electrode portion 31 with the dielectric layer 2 interposed therebetween. That is, when the first electrode portion 31 is virtually projected onto the second conductive layer 4 , the first electrode portion 31 is arranged in the second electrode portion 41 formation region. and the second electrode portion 41 may be configured. By adopting such a configuration, for example, when the tension sensor 1 (sensor main body 1a) is attached to clothes or the like so that the second conductive layer 4 faces the human body, the second electrode portion 41 can be used as a shield. , it is possible to effectively suppress the occurrence of capacitive coupling between the human body and the first electrode portion 31 . In addition, in the configuration shown in FIG. 2, the first conductive layer 3 and the second conductive layer 4 are arranged so that the first electrode portion 31 and the second electrode portion 41 are opposed to each other with the dielectric layer 2 interposed therebetween. However, as shown in FIG. 9, when the area of the second electrode portion 41 is larger than that of the first electrode portion 31, the dielectric layer 2 It is no longer necessary to strictly align the first conductive layer 3 and the second conductive layer 4 with respect to each other, and the tensile sensor 1 (sensor main body 1a) can be manufactured efficiently.

When adopting a configuration in which the first conductive layer 3 is provided with a plurality of first electrode portions 31, as shown in the schematic configuration cross-sectional view of FIG. The second electrode portion 41 is configured to have an area larger than the area, and the second electrode portion 41 is located at a position facing the region where the plurality of first electrode portions 31 are arranged with the dielectric layer 2 interposed therebetween. It may be configured to be arranged. That is, when virtually all of the plurality of first electrode portions 31 are projected onto the second conductive layer 4 , all of the plurality of first electrode portions 31 overlap the single second electrode portion 41 . , each of the first electrode portion 31 and the second electrode portion 41 may be configured. By adopting such a configuration, for example, when the tension sensor 1 is attached to clothing or the like so that the second conductive layer 4 faces the human body, the second electrode portion 41 can be used as a shield in the same manner as described above. , it is possible to effectively suppress the occurrence of capacitive coupling between the human body and each of the first electrode portions 31 . Moreover, in the configuration shown in FIG. 8, the first conductive layer 3 and the second conductive layer 3 are arranged so that the first electrode portions 31 and the second electrode portions 41 are arranged to face each other with the dielectric layer 2 interposed therebetween. Although it is necessary to perform positioning with respect to the layer 4 with high accuracy, the area of the second electrode portion 41 in plan view is larger than the area of the region where the plurality of first electrode portions 31 are arranged. , the need for strict alignment of the first conductive layer 3 and the second conductive layer 4 with respect to the dielectric layer 2 is eliminated, and the tension sensor 1 can be manufactured efficiently.

The inventor of the present invention prepared a sample A of the tensile sensor 1 (sensor body 1a) according to the present invention and a sample B corresponding to a comparative example, and evaluated the performance when actually stretched. , will be described below.

First, the structures of Sample A and Sample B will be described. First, in sample A, as shown in the schematic sectional view of FIG. 11(a), the tensile sensor 1 is formed by laminating the sensor main body 1a on one side of the stretchable base fabric 5. As shown in FIG. Further, the first conductive layer 3 on the upper side of the sensor body 1a is formed only by the first electrode portion 31, and similarly, the second conductive layer 4 arranged on the lower side of the sensor body 1a is formed only by the second electrode portion 41. It is formed by The first conductive layer 3 (first electrode portion 31) has a long rectangular shape in plan view with a width of 5 mm and a length of 145 mm, and the second conductive layer 4 (second electrode portion 41) has a width of It has an elongated rectangular form with a length of 8.5 mm and a length of 145 mm in plan view.

Each of the first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode portion 41) is configured such that its texture comprises a milling structure. More specifically, it has a bare milling structure and is formed by plating silver-plated fiber threads and bare polyurethane fiber threads. After knitting, the knitted fabric undergoes a heat setting process that is performed in the manufacturing stage, so that the intersections of the bare polyurethane fiber yarns are welded or coalesced to prevent fraying, and then cut to a predetermined size to be used as a sample. A first conductive layer 3 and a second conductive layer 4 are formed.

In sample A, polyurethane films (low melting point resin layers 22 and 23) having a melting point of 120° C. and a thickness of 50 μm are placed on both sides of a polyurethane film (high melting point resin layer 21) having a melting point of 200° C. and a thickness of 50 μm. A laminated film sheet is used as the dielectric layer 2, and after laminating the above-described first conductive layer 3 and second conductive layer 4 on both sides of this film sheet (dielectric layer 2), the bonding temperature is Heat pressing was performed at 180.degree.

Further, when laminating the first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode portion 41) on both sides of the film sheet (dielectric layer 2), as shown in FIG. ), the installation position of the second conductive layer 4 with respect to the first conductive layer 3 is shifted by 15 mm in the longitudinal direction, and the first conductive layer 3 and the second conductive layer 4 are laminated. was formed, and this portion was used as an electrode terminal.

The stretchable base fabric 5 employs a stretchable fabric generally used for supporters and the like. The elastic base fabric 5 has a thickness of 1 mm, a width of 20 mm, and a length of 330 mm, and is rectangular in plan view. The elastic base cloth 5 and the sensor main body 1a are fixed via an adhesive layer.

On the other hand, Sample B has the same structure as Sample A with respect to the first conductive layer 3, the second conductive layer 4, and the stretchable base fabric 5, but only the specific configuration of the dielectric layer 2 is changed. Specifically, as the dielectric layer 2, a polyurethane film having a melting point of 120° C. and a thickness of 150 μm is used. After laminating the same first conductive layer 3 and second conductive layer 4 as above, heat press is performed at a bonding temperature of 180 ° C., and the first conductive layer 3 and second conductive layer 4 are formed into a polyurethane film (dielectric layer 2) , and then fixed on the stretchable base cloth 5 via an adhesive layer (see the schematic sectional view of FIG. 11(c)).

After sandwiching the prepared sample A and sample B with a stand with a chuck, while applying a voltage to each of the first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode portion 41), The stand was moved and extended, and the change in capacitance accompanying the extension was measured. In addition, the measurement of the capacitance value accompanying elongation was performed a total of 3 times.

Table 1 and FIG. 12 show the relationship between the elongation rate of sample A according to the tensile sensor 1 and the value of the detected capacitance. Here, the capacitance value shown in Table 1 is the average value of three measurement results. In addition, in Table 1 and FIG. 12, an elongation rate of 0% means a state in which no elongation is performed.

From the results of Table 1 and FIG. 12, sample A has a detected capacitance value exceeding 400 pF, and the capacitance value increases by 3 pF per 1% increase in elongation rate. It can be seen that the change in capacitance can be detected with high precision and high sensitivity against expansion and contraction. In particular, since it has the characteristic that the value of capacitance increases linearly with its elongation, it is possible to detect and measure the deformation state and tensile force of the object to be detected with extremely high accuracy.

On the other hand, for sample B, the first conductive layer 3 (first electrode portion 31) and the second conductive layer 4 (second electrode portion 41) disposed on both surfaces of the dielectric layer partially interposed the dielectric layer. was short-circuited, and the change in capacitance could not be detected. The cause of the short circuit is that when the first conductive layer 3 and the second conductive layer 4 are heat-pressed, the fluffed portion generated on the surface of the conductive thread forming the first electrode portion or the second electrode portion This is believed to be caused by penetrating the polyurethane film (dielectric layer: melting point: 120° C., thickness: 150 μm) that has become fluid by heating, and coming into contact with the second electrode portion or the first electrode portion.

The inventor also conducted a test to confirm that the tension sensor 1 according to the present invention has characteristics that are less susceptible to noise. The test contents and test results will be described below.

First, the sample A and the sample C corresponding to the comparative example were prepared as samples to be subjected to a test for confirming the noise-susceptibility property. Sample C, as shown in the schematic sectional view of FIG. 13(a), is constructed by attaching a first conductive layer 3 and a second conductive layer 4 to both surfaces of a stretchable base fabric 5, respectively. The structures of the stretchable base fabric 5, the first conductive layer 3 and the second conductive layer 4 in the sample C are the same as those in the sample A described above.

For Sample A and Sample C having such configurations, first, change in capacitance value when elongated by 20% was measured. Table 2 shows the measurement results. In addition, the measurement of the capacitance value accompanying the elongation was performed a total of three times, and Table 2 shows the average value of the measurement results.

From the results in Table 2, for sample A related to the present invention, the capacitance value increased from "485.7 pF" to "546.3 pF" at 20% elongation, and the increased value was "60 0.6 pF". On the other hand, in the case of sample C according to the comparative example, it can be seen that the electrostatic capacitance value increased only slightly by "0.5 pF" even when stretched by 20% (51.9 pF→52.4 pF).

Next, a metal plate (made of aluminum with a thickness of 2 mm, a width of 35 mm, and a length of 310 mm) is brought close to the sample A and the sample C at a position where the distance from the first conductive layer 3 is 15 mm without being stretched. Then, the change in capacitance value was measured. The results are shown in Table 3.

From the results in Table 3, the amount of change in the capacitance value (corresponding to the noise signal) due to the proximity of the metal plate is "-0.4 pF" in the case of sample A according to the present invention, and the sample according to the comparative example. In the case of C, it is "-0.6 pF", and it can be seen that substantially the same noise signals are mixed in both cases. However, in the case of sample C according to the comparative example, the amount of change in the capacitance value when the metal plate is brought closer and the amount of change in the capacitance value when the metal plate is brought closer and the value when the elongation is 20% is of the same order (order of magnitude), and is greatly affected by the proximity of the metal plate, making it difficult to accurately detect the capacitance. More specifically, although there are aspects that cannot be said to be a strict quantitative evaluation, for example, in the case of sample C, even if the capacitance value increases by "0.4 pF" due to 20% elongation, the metal plate etc. When the dielectric comes close, the capacitance value drops by "0.6 pF", and although the tensile sensor is stretched by 20%, the detected capacitance value does not stretch. It becomes a value indicating the state, and the decompression state cannot be detected.

On the other hand, in the case of sample A according to the present invention, the amount of change in the capacitance value at 20% elongation is "60.6 pF", and the change in capacitance value when the metal plate is brought closer Since the amount is -0.4 pF, the effect of the amount of change in the capacitance value when the metal plate is brought closer to the amount of change in the capacitance value at 20% elongation is 1% or less. recognized to be. Although it is a simple calculation, even if the sample A is stretched by 1%, the ratio of the noise signal included in the detected capacitance value is about 13% (0.4 ÷ (60.6 ÷ 20 ) × 100 = 13.2%). In other words, it can be seen that sample A is a tensile sensor with a sufficient S/N ratio. The S/N ratio is the ratio between signal and noise, and stands for signal-noise ratio or signal-to-noise ratio. do.

As described above, when the tension sensor 1 according to the present invention is installed on a detection target and detects deformation or the like of the detection target, even if some other dielectric or conductor is close to the tension sensor 1, , it is possible to reduce the ratio of the noise signal mixed in the detection signal, and it can be said that the sensor is highly accurate and less susceptible to noise.

1 Tensile sensor 1a Sensor body 2 Dielectric layer 21 High melting point resin layer 22 First low melting point resin layer 23 Second low melting point resin layer 3 First conductive layer 31 First electrode part 32 First non-conductive part 4 Second conductive layer 41 Second electrode part 42 Second non-conductive part 5 Stretchable base cloth 6 Stretch adjustment layer

Claims (8)

A strip-shaped sensor body having a stretchable dielectric layer and stretchable first conductive layers and second conductive layers provided on one side and the other side of the dielectric layer, respectively,
The first conductive layer includes a strip-shaped first electrode portion formed of a conductive thread including a metal plating thread or a metal wire ,
The dielectric layer includes a high melting point resin layer, and a first low melting point resin layer and a second low melting point resin layer provided on both sides of the high melting point resin layer,
The first electrode portion is arranged so as to be impregnated with at least a portion of the first low melting point resin layer,
A tension sensor capable of detecting a change in capacitance between the first conductive layer and the second conductive layer due to expansion and contraction. 2. The tension sensor according to claim 1, wherein the melting point of said high melting point resin layer is higher than the melting points of said first low melting point resin layer and said second low melting point resin layer by 40[deg.] C. or more. The second conductive layer includes a strip-shaped second electrode portion formed of a conductive thread,
3. The method according to claim 1, wherein the second electrode portion is impregnated with at least a portion of the second low melting point resin layer at a position facing the first electrode portion through the dielectric layer. Tensile sensor as described. One surface side of the sensor body is provided with a stretchable base fabric laminated and arranged,
The tension sensor according to any one of claims 1 to 3, wherein the stretchable base fabric has stretch anisotropy. One surface side of the sensor body is provided with a tubular stretchable base fabric laminated and arranged,
The sensor main body is arranged such that its longitudinal direction is along the circumferential direction of the tubular stretchable base fabric,
Further comprising a strip-shaped stretch adjustment layer arranged along the circumferential direction of the tubular stretchable base fabric,
One end of the expansion/contraction adjustment layer is arranged at least in the vicinity of one end of the sensor main body, and the other end of the expansion/contraction adjustment layer is arranged in the vicinity of at least the other end of the sensor main body. 5. The tension sensor according to any one of claims 1 to 4, wherein said stretch adjusting layer comprises a ring-shaped structure on a tubular stretchable base fabric. 6. The tension sensor according to claim 5, wherein the expansion/contraction adjustment layer is formed including the same material as the high melting point resin layer. On one side and the other side of the stretchable dielectric layer having a high melting point resin layer and a low melting point resin layer provided on both sides of the high melting point resin layer, a conductive thread including a metal plating thread or a metal wire A first conductive layer configured as a knitted fabric structure or a woven fabric structure including a strip-shaped first electrode part formed, and a strip-shaped second electrode part formed from a conductive thread including a metal plating thread or a metal wire a lamination step of respectively arranging a second conductive layer configured as a knitted fabric structure or a woven fabric structure;
a heating step of heating the low-melting-point resin layer to make it flowable;
The first conductive layer and the second conductive layer are pressed so as to be close to each other, and the first conductive layer and the second conductive layer are impregnated with the low-melting-point resin layer in a flowable state. A method of manufacturing a tension sensor, comprising a pressing step of narrowing the inter-surface distance between the electrode portion and the second electrode portion. 8. The method of manufacturing a tensile sensor according to claim 7, wherein the pressing step holds the first conductive layer and the second conductive layer against each other through the non-flowing high-melting-point resin layer.

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