JP2016213277A - Cloth-like transducer and device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cloth-like transducer having excellent flexibility and stably generating a strong electric signal, a device using the signal from the transducer, and/or a device that functions by inputting the electric signal.SOLUTION: The transducer is made of a woven fabric including a plurality of piezoelectric units disposed roughly on the same plane so that conductive fibers B and piezoelectric fibers A are electrically connected and an electric signal is made to be an output or an input. The piezoelectric fiber A and the conductive fiber B constituting one piezoelectric unit are in direct contact with each other on a fiber surface, and/or are indirectly connected to each other through a conductive material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transducer that outputs an electric signal and / or changes its shape by inputting an electric signal by changing its shape due to an external force. More specifically, the present invention relates to a fabric-like transducer characterized by being able to change shape flexibly and three-dimensionally.

  In recent years, so-called wearable sensors have attracted attention, and products such as glasses and watches have begun to appear in the world. However, these devices have a feeling that they are worn, and a cloth-like shape, that is, a clothing-like shape that is the ultimate wearable is desired. As such a sensor, a sensor in which a piezoelectric element is attached to a cloth and a signal is extracted therefrom is disclosed (Patent Documents 1 and 2). However, since these require a separate structure on the surface of the woven or knitted fabric, it is difficult to adapt to a free-form surface, the touch is poor, and there is a lack of practicality such as problems in handling, workability, and workability. . In addition, there is a film-like structure made of a piezoelectric material and a conductive material (Patent Document 3), but this is also difficult to adapt to a free-form surface, has poor tactile feel, and is easy to handle. , Lack of practicality, such as causing problems in workability and workability.

  Furthermore, although a sensor (Patent Document 4) that detects resistance between conductive fibers has been proposed as a cloth-like sensor composed of only fibers, it detects pressure on the cloth and directly detects a change in shape. It wasn't.

  Further, Patent Document 5 includes a fabric-like piezoelectric element including two conductive fibers and one piezoelectric fiber, which have contact points with each other and include piezoelectric units arranged on substantially the same plane. Is disclosed. However, the fabric has the advantage of being flexible, but the piezoelectric fiber exists in the fabric in a free state to some extent, so that the electrical signal emitted from the piezoelectric fiber is stably generated as the fabric is deformed. There was a problem that it was difficult to transmit to the conductive fiber and it was difficult to stably exhibit the function as a transducer. Further, Patent Document 5 has no suggestion regarding a technique for improving piezoelectric performance by enhancing and stabilizing the contact point between the piezoelectric fiber and the conductive fiber in the fabric, and further technical improvement has been a problem.

Special table 2007-518886 JP-A-6-323929 JP 2002-203996 A JP 2006-284276 A International Publication No. 2014/058077 Pamphlet

  An object of the present invention is to provide a fabric-like transducer that uses a fiber material and produces a conventional knitted or knitted structure, which is rich in flexibility and stably generates a strong electric signal. Furthermore, it is to provide a device that uses a signal from the transducer and / or a device that functions by inputting an electric signal.

  The inventors of the present invention have found that it functions as a piezoelectric element by combining and arranging conductive fibers and piezoelectric fibers, and further, by introducing contact points between the piezoelectric fibers and the conductive fibers in the woven / knitted structure. The present inventors have found that the function as a piezoelectric element can be improved and completed the present invention.

That is, the present invention includes the following inventions.
1. A transducer that outputs or inputs an electrical signal, and is made of a woven or knitted fabric including a plurality of piezoelectric units in which conductive fibers and piezoelectric fibers are arranged on substantially the same plane so as to provide an electrical connection. Transformer characterized in that the piezoelectric fiber constituting the one piezoelectric unit and the conductive fiber are in direct contact with each other on the fiber surface and / or indirectly through a conductive material Sir.
2. 2. The piezoelectric unit according to claim 1, wherein the piezoelectric unit includes two conductive fibers and one piezoelectric fiber, and the conductive fibers, the piezoelectric fibers, and the conductive fibers are arranged in this order. Transducer.
3. 2. The transducer according to claim 1, wherein insulating fibers are arranged so that the conductive fibers in the piezoelectric unit are not electrically connected to conductive fibers and / or piezoelectric fibers in other piezoelectric units. .
4). 2. The transducer according to 1 above, wherein the piezoelectric fiber mainly contains polylactic acid.
5. 2. The transducer according to 1 above, wherein the piezoelectric fiber mainly contains poly-L-lactic acid or poly-D-lactic acid having an optical purity of 99% or more.
6). The transducer according to 1 above, wherein the piezoelectric fiber is uniaxially oriented and includes crystals.
7). 2. The transducer according to 1 above, wherein the conductive fiber is a metal-plated fiber.
8). 2. The transducer according to 1 above, wherein a flatness ratio of at least one of the piezoelectric fiber and the conductive fiber in direct contact with each other on the fiber surfaces is 2.0 or more.
9. The transducer according to any one of the above 1 to 8, which is a woven fabric containing a plurality of the piezoelectric units, the woven structure of which is a plain weave, a twill weave, a satin weave and a composite structure thereof.
10. The transducer according to 9 above, wherein a plurality of the fabrics are used in combination.
11. The transducer according to any one of 1 to 10 above, an amplification unit that amplifies an electrical signal output from the transducer in accordance with an applied pressure, and an electrical signal that is amplified by the amplification unit And an output means.
12 12. The device according to 11 above, further comprising transmission means for transmitting the electrical signal output from the output means to an external device.
13. 11. The transducer according to any one of 1 to 10, an output unit that outputs an electrical signal from the transducer in accordance with an applied pressure, and an electrical signal output from the output unit to an external device And a transmission means.
14 A device comprising: receiving means for receiving an electric signal; and the transducer according to any one of the above 1 to 10, to which the electric signal received by the receiving means is applied.

  According to the present invention, a fabric-like transducer having high flexibility can be obtained by using a fiber material and producing a conventional woven or knitted structure. Since the transducer according to the present invention is flexible, it is possible to realize a transducer that can input and output electric signals of any shape that can be realized by a foldable cloth shape such as a handkerchief, or a cloth shape.

1 is a schematic diagram of a satin fabric of Example 1. FIG. 3 is a schematic diagram of a plain fabric of Example 2. FIG. It is a block diagram which shows the 1st specific example of the device using the transducer of this invention. It is a block diagram which shows the 2nd specific example of the device using the transducer of this invention. It is a block diagram which shows the 3rd specific example of the device using the transducer of this invention.

The present invention is a transducer that outputs or inputs an electrical signal, which is made of a woven or knitted fabric including a plurality of piezoelectric units in which conductive fibers and piezoelectric fibers are arranged on substantially the same plane so as to provide an electrical connection. The piezoelectric fiber constituting the one piezoelectric unit and the conductive fiber are in direct contact with each other on the fiber surface and / or indirectly connected via a conductive material. Is achieved by a transducer. Each configuration will be described below.
(Conductive fiber)
Any known conductive fibers may be used as long as they exhibit electrical conductivity. For example, metal fibers, conductive polymer fibers, carbon fibers, fibrous or granular conductive fillers are dispersed. Examples thereof include fibers made of a polymer made to be polymerized, or fibers in which a conductive layer is provided on the surface of a fibrous material. Examples of the method for providing a conductive layer on the surface of the fibrous material include a metal coat, a conductive polymer coat, and winding of conductive fibers. Among these, a metal coat is preferable from the viewpoint of conductivity, durability, flexibility and the like. Specific methods for coating the metal include vapor deposition, sputtering, electrolytic plating, and electroless plating, but plating is preferable from the viewpoint of productivity.

  As a base fiber coated with a metal, a known fiber can be used regardless of conductivity, for example, polyester fiber, nylon fiber, acrylic fiber, polyethylene fiber, polypropylene fiber, vinyl chloride fiber, aramid fiber, In addition to polysulfone fiber, polyether fiber, polyurethane fiber, and the like, natural fibers such as cotton, hemp, and silk, semi-synthetic fibers such as acetate, and regenerated fibers such as rayon and cupra can be used. The base fibers are not limited to these, and known fibers can be arbitrarily used, and these fibers may be used in combination.

  Any metal may be used as long as the metal coated on the base fiber exhibits conductivity and exhibits the effects of the present invention.

  For example, gold, silver, platinum, copper, nickel, tin, zinc, palladium, indium tin oxide, copper sulfide, and a mixture or alloy thereof can be used.

  As the conductive fiber, a multifilament in which a plurality of filaments are bundled or a monofilament composed of a single filament may be used. The use as a multifilament is preferable from the viewpoint of long stability of electrical characteristics. The diameter of the monofilament is 1 μm to 5000 μm, preferably 2 μm to 100 μm. More preferably, it is 3 micrometers-50 micrometers. The number of filaments is preferably 1 to 100,000, more preferably 5 to 500, and still more preferably 10 to 100. If the diameter is small, the strength is lowered and handling becomes difficult, and if the diameter is large, flexibility is sacrificed. The cross-sectional shape of the conductive fiber is preferably a circle or an ellipse from the viewpoint of the design and manufacture of the piezoelectric element, but is not limited thereto.

Moreover, in order to efficiently extract the electrical output from the piezoelectric polymer, the electrical resistance is preferably low, and the volume resistivity is preferably 10 ⁻¹ Ω · cm or less, more preferably 10 ⁻² Ω · cm. cm or less, more preferably 10 ⁻³ Ω · cm or less. However, the resistivity of the conductive fiber is not limited as long as strength is obtained for signal detection.
(Piezoelectric fiber)
The piezoelectric fiber is a fiber having piezoelectricity. The piezoelectric fiber is preferably made of a piezoelectric polymer. As the piezoelectric polymer, any polymer exhibiting piezoelectricity such as polyvinylidene fluoride and polylactic acid can be used, but it is preferable that polylactic acid is mainly contained. Polylactic acid is easily oriented by stretching after melt spinning and exhibits piezoelectricity, and is excellent in productivity in that it does not require an electric field alignment treatment required for polyvinylidene fluoride and the like. Furthermore, the piezoelectric fiber made of polylactic acid has a small polarization due to its tensile or compressive stress in the axial direction, and it is difficult to function as a piezoelectric element, but a relatively large electrical output can be obtained depending on the shear stress, This is preferable in the piezoelectric element of the present invention having a structure that can easily apply a shear stress to the piezoelectric polymer.

  The piezoelectric polymer preferably contains mainly polylactic acid. “Mainly” means preferably 90 mol% or more, more preferably 95 mol% or more, and still more preferably 98 mol% or more.

  As polylactic acid, depending on its crystal structure, poly-L-lactic acid obtained by polymerizing L-lactic acid and L-lactide, D-lactic acid, poly-D-lactic acid obtained by polymerizing D-lactide, and those There are stereocomplex polylactic acid having a hybrid structure, and any of them can be used as long as it exhibits piezoelectricity. From the viewpoint of high piezoelectricity, poly-L-lactic acid and poly-D-lactic acid are preferable. Since poly-L-lactic acid and poly-D-lactic acid are reversed in polarization with respect to the same stress, they can be used in combination according to the purpose. The optical purity of polylactic acid is preferably 99% or more, more preferably 99.3% or more, and further preferably 99.5% or more. When the optical purity is less than 99%, the piezoelectricity may be remarkably lowered, and it may be difficult to obtain a sufficient electric output due to the shape change of the piezoelectric fiber. The piezoelectric polymer mainly contains poly-L-lactic acid or poly-D-lactic acid, and the optical purity thereof is preferably 99% or more.

  The piezoelectric fiber is preferably uniaxially oriented in the fiber axis direction of the fiber and contains crystals, more preferably uniaxially oriented polylactic acid having crystals. This is because polylactic acid exhibits large piezoelectricity in its crystalline state and uniaxial orientation.

  Since polylactic acid is a polyester that hydrolyzes relatively quickly, a known hydrolysis inhibitor such as an isocyanate compound, an oxazoline compound, an epoxy compound, or a carbodiimide compound may be added when heat and moisture resistance is a problem. . Further, if necessary, the physical properties may be improved by adding an antioxidant such as a phosphoric acid compound, a plasticizer, a photodegradation inhibitor, and the like.

  Polylactic acid may be used as an alloy with other polymers, but if polylactic acid is used as the main piezoelectric polymer, it contains at least 50% by weight or more based on the total weight of the alloy. It is preferably 70% by weight or more, and most preferably 90% by weight or more.

  Examples of the polymer other than polylactic acid in the case of alloy include polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate copolymer, polymethacrylate, and the like, but the invention is not limited thereto. Any polymer may be used as long as the desired piezoelectricity is exhibited.

  As the piezoelectric fiber, a multifilament in which a plurality of filaments are bundled or a monofilament composed of a single filament may be used. The use as a multifilament is preferable from the viewpoint of long stability of electrical characteristics. The diameter of the monofilament is 1 μm to 5000 μm, preferably 2 μm to 100 μm. More preferably, it is 3 micrometers-50 micrometers. The number of filaments is preferably 1 to 100,000, more preferably 5 to 500, and still more preferably 10 to 100.

  In order to make such a piezoelectric polymer into a piezoelectric fiber, any known technique for fiberizing the polymer can be employed as long as the effect of the present invention is achieved. Extruding and fiberizing technique, Piezoelectric polymer melt spinning and fiberizing technique, Piezoelectric polymer fiberizing process by dry or wet spinning, Piezoelectric polymer fiberizing by electrostatic spinning Techniques etc. can be adopted. As these spinning conditions, a known method may be applied according to the piezoelectric polymer to be employed, and a melt spinning method that is industrially easy to produce is usually employed.

As described above, when the piezoelectric polymer is polylactic acid, the fiber is preferably stretched because it is uniaxially stretched and exhibits greater piezoelectricity when it contains crystals.
(Almost on the same plane)
In the piezoelectric element of the present invention, the conductive fiber and the piezoelectric fiber are arranged on substantially the same plane. Here, “substantially on the same plane” means that the fiber axes of the fibers are arranged on a substantially plane, and “substantially” means that a thickness is generated at the intersection of the fibers. is there.

  For example, a form in which one piezoelectric fiber is further arranged in parallel between two parallel conductive fibers is a form on substantially the same plane. Further, even if the fiber axis of the one piezoelectric fiber is tilted in a state that is not parallel to the two parallel conductive fibers, they are substantially on the same plane. Furthermore, it is assumed that one conductive fiber and one piezoelectric fiber are aligned in parallel, and the other conductive fiber is crossed with the aligned conductive fiber and piezoelectric fiber. Are also on the same plane.

  By being arranged on a substantially flat surface, it is easy to form a cloth-like piezoelectric element by combining the piezoelectric units, and using a cloth-like piezoelectric element increases the degree of freedom in designing the shape of the transducer. Can do. Examples of the type of fabric include woven fabric, knitted fabric, and non-woven fabric.

The relationship between the piezoelectric fiber and the conductive fiber is appropriately selected depending on the shape change to be detected.
(Arrangement order)
The arrangement of the fibers in the piezoelectric unit is not particularly limited as long as the conductive fibers and the piezoelectric fibers are arranged to provide an electrical connection. For example, when the piezoelectric unit is composed of two conductive fibers and one piezoelectric fiber, the conductive fibers, the piezoelectric fibers, and the conductive fibers are preferably arranged in this order. By arranging in this way, the two conductive fibers of the piezoelectric unit do not come into contact with each other, and the piezoelectric material can be obtained without applying other means such as a technique such as coating an insulating material. It can function effectively as a unit.

  At this time, it is desirable that the conductive fiber and the piezoelectric fiber have a contact point that physically contacts each other. However, if the distance between the conductive fiber and the piezoelectric fiber is within 4 mm, An electrical connection can be provided without contact. The distance between the conductive fiber and the piezoelectric fiber is preferably 3 mm or less, more preferably 2 mm or less, still more preferably 1 mm or less, and most preferably 0.5 mm or less. If this distance is 4 mm or more, the electrical output accompanying the change in the shape of the piezoelectric fiber becomes small, making it difficult to use as a transducer.

Examples of the form include a form in which two conductive fibers are arranged in parallel and one piezoelectric fiber is arranged so as to intersect with these two conductive fibers. Further, two conductive fibers may be arranged as warps (or wefts), and one piezoelectric fiber may be arranged as wefts (or warps). In this case, it is preferable that the two conductive fibers are not in contact with each other, and preferably, an insulating substance, for example, an insulating fiber is interposed between the two conductive fibers. It is also possible to adopt a form in which an insulating material is coated only on the surface that is easily contacted so that the conductive fiber is in direct contact with the piezoelectric fiber.
(Insulating fiber)
The piezoelectric unit of the present invention includes an insulating fiber, and the insulating fiber includes a conductive fiber and a piezoelectric fiber so that the conductive fiber in the piezoelectric unit is not in contact with other conductive fibers and the piezoelectric fiber. May be placed between. In this case, the insulating fiber may be a stretchable material or a fiber having a shape for the purpose of improving the flexibility of the fabric. In addition, the conductive fiber in the piezoelectric unit may be arranged not to contact the conductive fiber and the piezoelectric fiber in the other piezoelectric unit.

  By disposing the insulating fibers in the piezoelectric units in this way, even when a plurality of piezoelectric units are combined, the conductive fibers do not come into contact, and the performance as a transducer can be improved.

As such an insulating fiber, it can be used if the volume resistivity is 10 ⁶ Ω · cm or more, more preferably 10 ⁸ Ω · cm or more, and further preferably 10 ¹⁰ Ω · cm or more.

  Examples of insulating fibers include polyester fibers, nylon fibers, acrylic fibers, polyethylene fibers, polypropylene fibers, vinyl chloride fibers, aramid fibers, polysulfone fibers, polyether fibers, polyurethane fibers, and other natural fibers such as cotton, hemp, and silk. Semi-synthetic fibers such as acetate, and regenerated fibers such as rayon and cupra can be used. It is not limited to these, A well-known insulating fiber can be used arbitrarily. Furthermore, these insulating fibers may be used in combination, or may be combined with a fiber having no insulating property to form a fiber having insulating properties as a whole.

  The insulating fiber may be a multifilament in which a plurality of filaments are bundled, or may be a monofilament composed of a single filament. The use as a multifilament is preferable from the viewpoint of long stability of the insulating characteristics. When used as a monofilament, the yarn diameter is 1 μm to 5000 μm, preferably 50 μm to 1000 μm. When used as a multifilament, the single yarn diameter is 0.1 μm to 5000 μm, preferably 2 μm to 100 μm. More preferably, it is 3 micrometers-50 micrometers. The number of filaments of the multifilament is preferably 1 to 100,000, more preferably 5 to 500, and still more preferably 10 to 100.

In addition, for the purpose of imparting flexibility to the fabric, any known shape of fiber can be used.
(Piezoelectric unit combination form)
In the present invention, a woven or knitted fabric containing a plurality of parallel piezoelectric units is preferable. With such a configuration, it is possible to improve the degree of deformation (flexibility) of the shape as a piezoelectric element.

  Such a woven or knitted fabric shape includes a plurality of piezoelectric units, and there is no limitation as long as it functions as a piezoelectric element. In order to obtain a woven or knitted shape, knitting and weaving may be performed with a normal loom or knitting machine. In the case of introducing a plurality of piezoelectric units into one piece of fabric, it may be produced continuously during weaving or knitting, or may be produced by joining a plurality of separately produced fabrics.

  Examples of the woven structure of the woven fabric include a three-layer structure such as plain weave, twill weave, and satin weave, a change structure, a single double structure such as a vertical double weave and a horizontal double weave, and a vertical velvet.

  The type of knitted fabric may be a circular knitted fabric (weft knitted fabric) or a warp knitted fabric. Preferable examples of the structure of the circular knitted fabric (weft knitted fabric) include flat knitting, rubber knitting, double-sided knitting, pearl knitting, tuck knitting, floating knitting, single-sided knitting, lace knitting, and bristle knitting. Examples of the warp knitting structure include single denby knitting, single atlas knitting, double cord knitting, half tricot knitting, back hair knitting, jacquard knitting, and the like. The number of layers may be a single layer or a multilayer of two or more layers. Further, it may be a napped woven fabric or a napped knitted fabric composed of a napped portion made of a cut pile and / or a loop pile and a ground tissue portion.

  When the piezoelectric unit is incorporated in a woven or knitted structure, the piezoelectric fiber itself has a bent portion. However, in order to efficiently exhibit the piezoelectric performance as a piezoelectric element, the bending of the piezoelectric fiber is necessary. Smaller portions are preferred. Therefore, the woven fabric is preferred for the woven fabric and the knitted fabric.

  Even in this case, as described above, the piezoelectric fiber is more efficiently expressed when the bending portion of the piezoelectric fiber is smaller. Therefore, the twill weave is preferable to the plain weave as the weave structure, and the satin weave (salmon weave) than the twill weave. Is preferred. In particular, among satin woven (red satin weave), when the number of jumps is in the range of 3 to 7, it is preferable because the retention of the woven structure and the piezoelectric performance are exhibited at a high level.

  The woven structure is appropriately selected depending on the shape change to be detected. For example, when it is desired to detect bending, it is preferable that the plain weave structure and the piezoelectric fiber and the conductive fiber have a parallel relationship. When torsion detection is desired, the satin weave structure, the piezoelectric fiber and the conductive fiber are A direct relationship is preferred.

In addition, since polylactic acid, which is a piezoelectric fiber, is easily charged, it may easily malfunction. In such a case, the piezoelectric fiber from which a signal is to be taken out can be grounded (grounded). As a method of grounding (grounding), it is preferable to dispose conductive fibers separately from the conductive fibers from which signals are extracted. In this case, the volume resistivity of the conductive fiber is preferably 10 ⁻¹ Ω · cm or less, more preferably 10 ⁻² Ω · cm or less, and still more preferably 10 ⁻³ Ω · cm or less.
(Contact point between piezoelectric fiber and conductive fiber)
The woven or knitted fabric of the present application is characterized in that the piezoelectric fiber and the conductive fiber have sufficient contacts. The function of the fabric of the present application as a transducer is that deformation of the piezoelectric fiber causes electrostatic polarization on the surface of the piezoelectric fiber, and an electrical signal derived from this electrostatic polarization is taken out through the conductive fiber. Therefore, since the piezoelectric fiber and the conductive fiber have sufficient contacts, the contact resistance between them is reduced, and a strong electric signal can be obtained.

  Here, having sufficient contact points means a state having an abundant conduction area between the piezoelectric fiber and the conductive fiber, which is not generated simply by creating a woven or knitted fabric.

  One preferred form of a state having sufficient contact includes a state in which the piezoelectric fiber and / or the conductive fiber are deformed flat along the surface of each other at the intersection. Such a state can be obtained by increasing the weft and warp tension when weaving the fabric, or by pressing the fabric with a strong force and / or pressing in a heated atmosphere. In this case, it is preferable that a molecular level intrusion or chemical bond formation occurs at the contact interface with the conductive fiber in contact with the piezoelectric fiber, and the adhesive state is not adhered, but the contact area increases due to deformation of each fiber surface. The increasing state can also be regarded as a state having sufficient contacts. When fibers adhere to each other, it indicates a state in which the interface between the piezoelectric fibers and the conductive fibers is unclear when the cross section of the fibers is observed. In addition, when the contact area is increased, when the cross section of the cross section of the fiber is observed, the piezoelectric fiber or the conductive fiber is deformed significantly flat in accordance with the shape of the crossed fiber surface. . It can be evaluated by the following method whether it is deform | transforming remarkably flat in this way.

The fabric is solidified after being impregnated with an adhesive so as not to change its state, and is fixed to a thin sheet. A vertical cross section of the piezoelectric fiber at a portion intersecting with the conductive fiber is cut out with a feather cutter, and the cross section is observed with a microscope. On the cross section of the piezoelectric fiber, an x axis parallel to a plane formed by the fabric and a y axis perpendicular to the x axis are taken. If the fiber whose cross-section is to be observed is a monofilament, draw a rectangle with the minimum size that the entire fiber cross-section of one filament will be in, so that each side is parallel to the x-axis and y-axis. Let the length of the side be x ₁ and the length of the side in the y-axis direction be y ₁ . If the fiber whose cross-section is to be observed is a multifilament, draw a rectangle of the smallest size that contains the cross-sections of all the filaments in one multifilament so that each side is parallel to the x-axis and y-axis. The length of the side of the rectangle in the x-axis direction is x ₁ , and the length of the side in the y-axis direction is y ₁ .

  From these measurement results, the oblateness is calculated from the following formula (1).

Flatness ratio = x ₁ ÷ y ₁ (1)
The flatness is calculated for 10 or more different points, and the average value is adopted. When the average value of the flatness is 2.0 or more, in the present application, the piezoelectric fiber at the intersecting portion is significantly flattened according to the shape of the conductive fiber surface of the intersecting partner, that is, the piezoelectric fiber is conductive. It is judged that there is a sufficient contact at the intersection that intersects the sex fibers. It is preferable that the piezoelectric fiber at the intersection is deformed more flatly because the contact area at the intersection is increased. Therefore, the aspect ratio is more preferably 2.3 or more, and further preferably 2.5 or more.

  Further, in the case of a fabric using multifilaments as piezoelectric fibers, it is possible to form a multifilament in which the gaps between the filaments constituting the multifilament are compressed to form a dense multifilament. From the viewpoint of facilitating extraction of an electric signal derived from piezoelectricity that is present in the vicinity.

  In order to achieve the flatness as described above, a conventionally known pressing method is preferably used. In particular, when polylactic acid fibers are used as piezoelectric fibers, it is preferable to perform hot pressing within 10 minutes at a temperature between the glass transition point of 60 ° C. and the melting point, preferably between 70 ° C. and 160 ° C. . Further, it is more preferable to perform hot pressing at a temperature near the melting start temperature of the piezoelectric fiber (between 140 ° C. and 160 ° C. for polylactic acid) and at a temperature at which the conductive fiber and the insulating fiber do not melt. The hot pressing is preferably performed by a roll press machine that can be carried out continuously.

  Moreover, when multifilament is used for the piezoelectric fiber or the conductive fiber, it is preferable that the number of twists of the multifilament is small in order to achieve the flatness as described above. If the number of twists is too large, the fiber is not easily deformed flat, and the contact cannot be made sufficiently large, which is not preferable. From this viewpoint, the number of twists is preferably 1000 or less, preferably 500 or less, and more preferably 300 or less per 1 m.

  Another preferred form of a state having sufficient contacts is a state in which an indirect contact made of a conductive material is provided between the piezoelectric fiber and the conductive fiber. The conductive material used for the indirect contact can be anything as long as it has a function of being electrically connected by being interposed between the piezoelectric fiber and the conductive fiber, such as a conductive material such as solder, metal or carbon. A conductive paste, a conductive adhesive or a conductive adhesive containing a filler is preferably used. In particular, a conductive adhesive having an adhesive force is more preferable because the deformation of the fabric can be efficiently transmitted to the piezoelectric fiber to easily develop the piezoelectric function and the indirect contact can be stably maintained for a long period of time. The conductive material may be preliminarily applied to the fiber surface or contained in the fiber, followed by a weaving or knitting process, and a surface precipitation or curing process may be performed as necessary in the state of the fabric. After that, a conductive material can be applied or impregnated. In order to prevent short-circuiting between different conductive fibers and conduction of unintended parts, the conductive material is applied to the conductive fibers or contained in the conductive fibers, and then subjected to a weaving or knitting process, and the state of the fabric. Therefore, it is preferable to take a method of undergoing surface precipitation or a curing step as necessary.

In order to achieve the object of the present application, any of the above-described weaving and weaving with a strong weft / warp, increase in direct contact area by pressing, and installation of indirect contact by conductive material may be used. Can also be implemented in combination.
(Multiple piezoelectric elements)
It is also possible to use a plurality of piezoelectric elements side by side. The arrangement may be one-dimensionally arranged in one step, two-dimensionally stacked, and may be knitted into a cloth or used as a braid. Thereby, a cloth-like or string-like piezoelectric element can be realized. In forming a cloth or string, as long as the object of the present invention is achieved, the fibers may be combined with other fibers other than the piezoelectric element and mixed, woven, knitted, etc., or incorporated into a resin or the like. You may use it.
(Applied technology for piezoelectric elements)
Regardless of the mode of the transducer of the present invention, contact with the surface, pressure, and shape change can be output as an electrical signal. FIG. 3 is a block diagram showing a first specific example of a device using the transducer of the present invention. For example, the transducer 11 of the present invention, an amplifying unit 12 for amplifying an electric signal output from the transducer 11 in accordance with an applied pressure, and an output unit 13 for outputting the electric signal amplified by the amplifying unit 12 If the device 101 including the transmission unit 14 for transmitting the electrical signal output from the output unit 13 to an external device (not shown) is configured, the device 101 is output by contact with the surface of the transducer 11, pressure, or shape change. Since the electrical signal can be easily taken out, it can be applied to various applications. Whether the transmission method by the transmission means 14 is wireless or wired may be appropriately determined according to the device to be applied.

  Further, not only the amplification means but also known signal processing means such as noise removing means and means for processing in combination with other signals can be used in combination. The order of connection of these means can be appropriately changed according to the purpose. Of course, the electrical signal output from the transducer 11 may be signal-processed after being transmitted to the external device as it is.

  Specific examples include touchscreens, human and animal surface pressure sensors, joint and bends, torsion, and expansion / contraction in the form of clothing, supporters, handkerchiefs, including hats, gloves, and socks. Sensor. For example, when used for humans, it can be used as an interface for detecting contact and movement, collecting information on movement of joints and the like for medical purposes, amusement purposes, and moving lost tissues and robots. In addition, it can be used as a stuffed animal that imitates animals and humanoids, a surface pressure sensor of a robot, a sensor that detects bending, twisting, and expansion / contraction of a joint. In addition, it can be used as a surface pressure sensor or shape change sensor for bedding such as sheets and pillows, shoe soles, gloves, chairs, rugs, bags, and flags.

  Furthermore, since the sensor of the present invention is in the form of a cloth, it has stretchability and flexibility, so that it can be used as a surface pressure sensor or a shape change sensor by pasting or covering all or part of the surface of any structure. be able to.

  In addition, since the transducer of the present invention can take out an electrical signal as an output, it can also be used as a power generation element such as a power source for storing other devices or storing electricity. FIG. 4 is a block diagram showing a second specific example of a device using the transducer of the present invention. For example, the transducer 11 of the present invention, an amplifying unit 12 for amplifying an electric signal output from the transducer 11 in accordance with an applied pressure, and an output unit 13 for outputting the electric signal amplified by the amplifying unit 12 If the device 102 consisting of the above is configured, the electrical signal output by the contact with the surface of the transducer 11, the pressure, and the shape change is used as a power source for moving other devices, or is stored in the power storage device. Can do.

  Further, not only the amplification means but also known signal processing means such as noise removing means and means for processing in combination with other signals can be used in combination. The order of connection of these means can be appropriately changed according to the purpose. Of course, the electrical signal output from the transducer 11 may be signal-processed after being transmitted to the external device as it is.

  Specific examples include power generation by using moving parts of humans, animals, robots, machines, etc. that move spontaneously, shoe soles, rugs, power generation on the surface of structures that receive external pressure, Power generation by changing the shape of the. In order to generate an electric signal due to a shape change in the fluid, it is possible to adsorb the chargeable substance in the fluid or to suppress the adhesion.

  On the other hand, the transducer according to the present invention can generate a mechanical force when an electric signal is inputted, regardless of the mode. FIG. 5 is a block diagram showing a third specific example of a device using the transducer of the present invention. For example, if a device 103 comprising a receiving means 15 for receiving an electric signal from an external device (not shown) and the transducer 11 of the present invention to which the electric signal received by the receiving means 15 is applied, the device 103 is inputted. A force corresponding to the electrical signal can be generated in the transducer 11.

  Further, not only the amplification means but also known signal processing means such as noise removing means and means for processing in combination with other signals can be used in combination. The order of connection of these means can be appropriately changed according to the purpose. Of course, the electrical signal output from the transducer 11 may be signal-processed after being transmitted to the external device as it is.

  Specific examples of applications that use electrical signals as input include applying electrical signals to cloth-shaped piezoelectric elements to move objects placed on the fabric surface, wrapping objects, and compressing them. Or can be vibrated. Various shapes can be expressed by controlling electric signals applied to the piezoelectric elements constituting the fabric. Furthermore, it is possible to function as a speaker by vibrating the fabric itself.

  Other examples include clothing that includes hats, gloves and socks, supporters, handkerchiefs, actuators that apply pressure to the surface of people, animals and objects, bending, twisting, and stretching of joints. There are actuators to support. For example, when used in humans, it can be used for amusement applications that give contact, movement, or pressure, or to move lost tissue. In addition, it can be used as a stuffed animal that imitates animals or humanoids, an actuator that inflates or stretches the surface of a robot, or an actuator that imparts movements such as bending, twisting, and expansion / contraction to joints. Others include actuators that move the surface of bedclothes such as sheets and pillows, shoe soles, gloves, chairs, rugs, bags, and flags, and actuators of all shapes like cloth, such as handkerchiefs, furoshikis, and bags that change shape with electrical signals. Can be used as

  Furthermore, since the actuator of the present invention is in the form of a cloth, it has stretchability and flexibility, so that it can be used as an actuator that changes the surface shape by pasting or covering all or part of the surface of any structure. .

  Since the transducer of the present invention can move with an electric signal as an input, it can also be used as a speaker that generates sound by vibration.

Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples.
(1) Measurement of fiber flatness A sheet in which a fabric is fixed with an epoxy adhesive is prepared, a vertical cross section of a piezoelectric fiber at a portion intersecting with another fiber is cut out with a feather cutter, and the cross section is observed with a microscope. Observed at. On the fiber cross section, an x axis parallel to the plane formed by the fabric and a y axis perpendicular to the x axis were taken. If the fiber whose cross-section is to be observed is a monofilament, draw a rectangle with the minimum size that the entire fiber cross-section of one filament will be in, so that each side is parallel to the x-axis and y-axis. The length of the side was x ₁ , and the length of the side in the y-axis direction was y ₁ . If the fiber whose cross-section is to be observed is a multifilament, draw a rectangle of the smallest size that contains the cross-sections of all the filaments in one multifilament so that each side is parallel to the x-axis and y-axis. The length of the side in the x-axis direction of the rectangle was x ₁ , and the length of the side in the y-axis direction was y ₁ .

  From these measurement results, the oblateness was calculated from the following formula (2).

Flatness ratio = x ₁ ÷ y ₁ (2)
The flatness was calculated for 10 or more different points, and the average value was adopted.
(2) Optical purity of polylactic acid:
Collect 0.1 g of polylactic acid fiber (one bundle in the case of multifilament) constituting the fabric, add 1.0 mL of 5 mol / L sodium hydroxide aqueous solution and 1.0 mL of methanol, and heat to 65 ° C. Set in a set water bath shaker, hydrolyze for about 30 minutes until the polylactic acid becomes a homogeneous solution, and further neutralize to pH 7 by adding 0.25 mol / liter of sulfuric acid to the hydrolyzed solution. Then, 0.1 mL of the decomposition solution was collected, diluted with 3 mL of high-performance liquid chromatography (HPLC) mobile phase solution, and filtered through a membrane filter (0.45 μm). This adjustment solution was subjected to HPLC measurement, and the ratio of L-lactic acid monomer to D-lactic acid monomer was quantified. When the amount of one polylactic acid fiber is less than 0.1 g, the amount of other solution used is adjusted according to the amount that can be collected, and the concentration of polylactic acid in the sample solution used for HPLC measurement is 100 minutes from the above. It was made to be in the range of 1.
<HPLC measurement conditions>
Column: “Sumichiral (registered trademark)” OA-5000 (4.6 mm × φ150 mm) manufactured by Sumika Chemical Analysis Co., Ltd.
Mobile phase: 1.0 mmol / liter copper sulfate aqueous solution Mobile phase flow rate: 1.0 ml / min Detector: UV detector (wavelength 254 nm)
Injection volume: 100 peak areas derived from microliter L-lactic acid monomer and _{S LLA,} D-lactic acid monomer peak areas derived from the When _{S DLA, S LLA} and _{S DLA} is molarity _{M LLA} and L- lactic acid monomer Since it was proportional to the molar concentration M _DLA of the D-lactic acid monomer, the larger value of S _LLA and S _DLA was taken as S _MLA , and the optical purity was calculated by the following formula 3.

Optical purity (%) = S _MLA ÷ (S _LLA + S _DLA ) × 100 (3)
(Manufacture of polylactic acid)
The polylactic acid used in the examples was produced by the following method.

To 100 parts by weight of L-lactide (manufactured by Musashino Chemical Laboratory, Inc., optical purity 100%), 0.005 part by weight of octylate is added, and 180 ° C. in a reactor equipped with a stirring blade in a nitrogen atmosphere. Then, 1.2 times equivalent of phosphoric acid was added to tin octylate, and then the remaining lactide was removed under reduced pressure at 13.3 Pa to obtain chips to obtain poly-L-lactic acid (PLLA1). . The resulting PLLA1 had a weight average molecular weight of 152,000, a glass transition point (Tg) of 55 ° C., and a melting point of 175 ° C.
(Piezoelectric fiber)
PLLA1 melted at 240 ° C. was discharged from a 24-hole cap at 20 g / min and taken up at 887 m / min. This unstretched multifilament yarn was stretched 2.3 times at 80 ° C. and heat-set at 100 ° C. to obtain a multifilament uniaxially stretched yarn of 84 dTex / 24 filament. The optical purity of the piezoelectric fiber A was 99.8%. Further, eight piezoelectric fibers A were bundled to obtain a piezoelectric fiber D.
(Conductive fiber)
The silver-plated nylon product name “AGposs” made by Mitsuji Fuji Textile Industry was used. The volume resistivity of this fiber was 1.1 × 10 ⁻³ Ω · cm. This fiber was designated as conductive fiber B.

The product name “HTS40 3K”, which is a carbon fiber multifilament manufactured by Toho Tenax Co., Ltd., was used as the conductive fiber E. The conductive fiber E was a multifilament having a bundle of 3000 filaments having a diameter of 7.0 μm, and the volume resistivity was 1.6 × 10 −3 Ω · cm.
(Insulating fiber)
Polyethylene terephthalate melted at 280 ° C. was discharged from a 24-hole cap at 22 g / min and taken up at 800 m / min. The undrawn yarn was drawn at 80 ° C. and 2.5 times, and heat-fixed at 180 ° C. to obtain a multifilament drawn yarn of 84 dTex / 24 filament. This fiber was designated as insulating fiber C.

Polyethylene terephthalate melted at 280 ° C. was discharged from a 48-hole cap at 45 g / min and taken up at 800 m / min. The undrawn yarn was drawn at 80 ° C. and 2.5 times, and heat fixed at 180 ° C. to obtain a 167 dTex / 48 filament multifilament drawn yarn. Four bundles of this multifilament drawn yarn were combined to make insulating fiber F.
Example 1
As shown in FIG. 1, a satin woven fabric was produced in which piezoelectric fibers A and insulating fibers C were arranged on the warps, and conductive fibers B and insulating fibers C were arranged on the wefts.

  The satin fabric was pressed at 110 ° C. and a pressure of 1 MPa for 5 minutes to obtain a satin fabric in which the piezoelectric fibers A and the conductive fibers B contact each other at the fiber surfaces.

  The piezoelectric fiber A in the satin fabric was cut perpendicularly at the intersection with the conductive fiber B, and the flatness was measured based on observation with a scanning electron microscope. As a result, the flatness was 2.74. Deformed flat, the piezoelectric fiber had sufficient direct contact with the conductive fiber.

A pair of conductive fibers B sandwiching the piezoelectric fibers A in the satin fabric after the press treatment were connected to an oscilloscope (digital oscilloscope DL6000 series trade name “DL6000” manufactured by Yokogawa Electric Corporation) as signal lines. When the fabric was bent or twisted with the signal line connected, a strong voltage signal of S / N = 19.3 was obtained.
Example 2
As shown in FIG. 2, a plain woven fabric was produced in which insulating fibers F were arranged on the warp and piezoelectric fibers D, conductive fibers E, and insulating fibers F were arranged on the wefts. Furthermore, the conductive adhesive Dotite D-363 (manufactured by Fujikura Kasei Co., Ltd.) is attached to the point G where the piezoelectric fiber D and the conductive fiber E come close to each other using a micropipette, and then dried at room temperature for 5 hours Then, an indirect contact through a conductive material was created.

A pair of conductive fibers E sandwiching the piezoelectric fibers D in the plain fabric were connected to an oscilloscope (digital oscilloscope DL6000 series trade name “DL6000” manufactured by Yokogawa Electric Corporation) as a signal line. When the cloth in the vicinity of the point where the conductive adhesive was applied was bent or twisted with the signal line connected, a strong voltage signal of S / N = 15.6 was obtained.
Comparative Example 1
Using the satin fabric produced in Example 1, the same evaluation as in Example 1 was performed without pressing. The flatness was 1.73, and it did not deform significantly flat at the intersection, and the piezoelectric fiber did not have sufficient direct contact with the conductive fiber. Further, the piezoelectric characteristics were evaluated in the same manner as in Example 1. As a result, the voltage signal S / N = 8.1, and the signal was weaker than that of the satin fabric subjected to press processing in Example 1, and was affected by noise. It was easy.
Comparative Example 2
When the plain fabric prepared in Example 2 was used and evaluated in the same manner as in Example 2 without using a conductive adhesive, the voltage signal S / N was 6.8. Compared to plain fabric using adhesive, the signal was weak and susceptible to noise.

DESCRIPTION OF SYMBOLS A Piezoelectric fiber B Conductive fiber C Insulating fiber D Piezoelectric fiber E Conductive fiber F Insulating fiber G Conductive adhesive application part 1 Oscilloscope 2 Evaluation wiring 3 Evaluation wiring 11 Transducer 12 Amplification means 13 Output means 14 Transmitting means 15 Receiving means 101, 102, 103 Device

Claims (14)

  A transducer that outputs or inputs an electrical signal, and is made of a woven or knitted fabric including a plurality of piezoelectric units in which conductive fibers and piezoelectric fibers are arranged on substantially the same plane so as to provide an electrical connection. A transducer characterized in that the piezoelectric fibers constituting the one piezoelectric unit and the conductive fibers are in direct contact with each other on the fiber surfaces and / or indirectly connected via a conductive material. .   The piezoelectric unit includes two conductive fibers and one piezoelectric fiber, and the conductive fibers, the piezoelectric fibers, and the conductive fibers are arranged in this order. Transducer.   The transformer according to claim 1, wherein insulating fibers are arranged so that the conductive fibers in the piezoelectric unit are not electrically connected to conductive fibers and / or piezoelectric fibers in other piezoelectric units. Deucer.   The transducer according to claim 1, wherein the piezoelectric fiber mainly contains polylactic acid.   The transducer according to claim 1, wherein the piezoelectric fiber mainly contains poly-L-lactic acid or poly-D-lactic acid having an optical purity of 99% or more.   The transducer of claim 1, wherein the piezoelectric fibers are uniaxially oriented and comprise crystals.   The transducer according to claim 1, wherein the conductive fiber is a metal-plated fiber.   The transducer according to claim 1, wherein a flatness ratio of at least one of the piezoelectric fiber and the conductive fiber in direct contact with each other on the fiber surfaces is 2.0 or more.   The transducer according to any one of claims 1 to 8, which is a woven fabric containing a plurality of the piezoelectric units, the woven structure of which is a plain weave, a twill weave, a satin weave and a composite structure thereof.   The transducer according to claim 9, wherein a plurality of the fabrics are used in combination. The transducer according to any one of claims 1 to 10,
Amplifying means for amplifying an electrical signal output from the transducer in response to an applied pressure;
Output means for outputting the electrical signal amplified by the amplification means;
A device comprising:   The device according to claim 11, further comprising a transmission unit that transmits the electrical signal output from the output unit to an external device.   The transducer according to any one of claims 1 to 10, output means for outputting an electrical signal from the transducer in accordance with an applied pressure, and the electrical signal output from the output means to an external device A transmission means for transmitting. Receiving means for receiving an electrical signal;
The transducer according to any one of claims 1 to 10, wherein an electrical signal received by the receiving means is applied;
A device comprising: