JP2019138888A - Sheet-like sensor and method of using the same - Google Patents

Abstract

To provide a sheet-like sensor which allows for easily determining a pressure-receiving site more accurately, and a method of using the same.SOLUTION: A sheet-like sensor 1 comprises piezoelectric fiber 100 arranged therein, the piezoelectric fiber 100 having reduced piezoelectricity except within a portion thereof in the sheet-like sensor 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a planar sensor using piezoelectric fibers and a method of using the same.

  A planar sensor using a piezoelectric fiber is known (see, for example, Patent Document 1). When the linear sensor is deformed by force, a voltage is induced between the inner conductor and the outer conductor. This characteristic can be used for a tactile sensor, a vibration sensor, or the like.

JP2015-204429A

  When a pressure sensor is applied to a planar sensor such as Patent Document 1, it may not be possible to determine which part the pressure is for.

  In view of the above circumstances, an object of the present invention is to provide a planar sensor that can more easily determine a portion subjected to pressure and a method for using the planar sensor.

The planar sensor of the first aspect of the present invention that solves the above-mentioned object is
A planar sensor in which piezoelectric fibers are arranged,
The piezoelectric fiber has a reduced piezoelectric characteristic except for a part in the planar sensor.
It is characterized by that.

  According to this planar sensor, the piezoelectric fiber can be disposed at a desired location of the planar sensor, and the portion that has received the pressure can be more accurately determined.

Moreover, the planar sensor of the second aspect of the present invention that solves the above object is
A planar sensor provided with a plurality of piezoelectric fibers provided for a first region and a second region that are predicted to have a high frequency of pressure,
In the piezoelectric fiber, the number of intersections between the two piezoelectric fibers intersecting in the first region and the two piezoelectric fibers intersecting in the second region is 1 or less. Is provided,
It is characterized by that.

  According to this planar sensor, it is possible to more accurately determine the portion that has received pressure.

Moreover, the planar sensor of the third aspect of the present invention that solves the above-mentioned object is
A planar sensor in which a plurality of piezoelectric fibers are arranged in a net shape along each of a first direction and a second direction intersecting the first direction,
The first direction and the second direction are:
It is a direction that obliquely intersects the longitudinal direction of the planar sensor,
It is characterized by that.

  According to this planar sensor, it is possible to more accurately determine the portion that has received pressure.

The surface sensor described above is
Conductive wires may be arranged adjacent to at least a part of the plurality of piezoelectric fibers.

  According to this planar sensor, the influence of noise can be reduced.

In addition, the surface sensor described above is
The conductor may have the same impedance as that of the adjacent piezoelectric fiber.

  According to this planar sensor, the influence of noise can be further reduced.

In addition, the surface sensor described above is
Have an external board,
The piezoelectric fiber has a piezoelectric body, an inner conductor insulated by the piezoelectric body, and an outer conductor provided on the outer peripheral side of the inner conductor,
The piezoelectric fiber is fixed to the external substrate through a first hole and a second hole formed in the external substrate,
In the first hole, the exposed outer conductor is soldered,
The piezoelectric body is exposed from the first hole to the second hole,
The end of the state where the inner conductor is folded back to the piezoelectric body passes through the second hole, and is fixed inside the cylinder,
The cylinder may be soldered in the second hole.

  According to this planar sensor, it can be firmly fixed to the external substrate.

In addition, the surface sensor described above is
A metal fiber layer may be provided on a surface not in contact with the installation surface.

  According to this planar sensor, durability can be improved.

The method of using the planar sensor of the present invention that solves the above-described object is as follows.
A first surface sensor that is the surface sensor described above;
Using the second planar sensor that is the planar sensor described above,
In a state where the inspection object is sandwiched between the first planar sensor and the second planar sensor, the position of the pressure change in each of the first planar sensor and the second planar sensor is detected. It is characterized by that.

  According to the usage method of this planar sensor, it is possible to evaluate the buffer performance of the inspection object sandwiched between the two planar sensors.

Moreover, the usage method of the said planar sensor is as follows.
For position adjustment from the first planar sensor to the second planar sensor through the inspection object in a state where the inspection object is sandwiched between the first planar sensor and the second planar sensor Apply the pressure of
When the pressure for adjusting the position is applied, the position information of the pressure change is acquired in each of the first planar sensor and the second planar sensor,
The positional relationship of the pressure change detected by the first planar sensor and the second planar sensor may be corrected based on the positional information.

  According to the usage method of this planar sensor, the position of the pressure change detected by the two planar sensors can be matched, and the buffering performance of the sandwiched inspection object can be more accurately evaluated.

  According to the present invention, it is an object of the present invention to provide a planar sensor that can more easily determine a portion subjected to pressure and a method for using the planar sensor.

(A) is a figure which shows shoe SH to which the planar sensor of this invention is applied, (B) is a figure which shows the planar sensor installed in this shoe SH. It is a figure which shows the structure of the planar sensor shown to FIG. 1 (B). 3 is a cross-sectional view schematically showing the structure of the piezoelectric fiber 100 of the planar sensor 1. FIG. 2 is a view showing the shape of an inner conductor of a piezoelectric fiber 100. FIG. (A) is a figure which shows the planar sensor 1 of this embodiment, (B) shows the planar sensor Z of embodiment which made the wiring direction of the piezoelectric fiber 100 different from this embodiment. FIG. (A) is a figure which shows the planar sensor 1 of this embodiment, (B) is a figure which shows the planar sensor Z of the comparison object shown to FIG. 5 (B). (A) is a figure which shows the planar sensor 1 for fingers of a hand, (B) is a figure which shows the state which applied the planar sensor 1 for fingers of the hand to the index finger of the hand HA. It is a figure which shows embodiment which made the 1st direction and the 2nd direction differ with respect to this embodiment. It is a figure which shows 1 A of planar sensors which have arrange | positioned the fiber 110 used for a general cloth etc. between the piezoelectric fibers 100 arrange | positioned along the 1st direction and the 2nd direction. It is the schematic diagram which looked at the structure of 1 A of planar sensors of FIG. 9 from the side surface. In addition to the first layer 10 in which the piezoelectric fibers 100 are arranged along the first direction and the second layer 11 in which the piezoelectric fibers 100 are arranged along the second direction, non-piezoelectric fibers FIG. 10 is a diagram showing a planar sensor 1B to which a third layer 14 according to 110 is added. It is a figure which shows the structure which braided the piezoelectric fiber 100 adjacent. It is a figure which shows the tread board 3 which provided the convex part 30. FIG. It is a figure which shows the example which used the planar sensor 1 in multiple numbers. It is a figure which shows an example of the piezoelectric fiber 100 fixed to the board | substrate FL. 2 is a cross-sectional view schematically showing an example of the structure of a piezoelectric fiber 100. FIG. 2 is a cross-sectional view schematically showing an example of the structure of a piezoelectric fiber 100. FIG. It is a figure which shows an example of how to wind a piezoelectric film. It is a figure which shows an example of the cross | intersection of two vertical and horizontal piezoelectric fibers. It is a figure which shows an example of the intersection of three piezoelectric fibers. It is a figure which shows an example of the planar sensor which provided the piezoelectric fiber in the one part area | region.

[Surface sensor with piezoelectric fiber on the entire surface]
Embodiments of the present invention will be described below with reference to the drawings.

  First, an embodiment in which the planar sensor of the present invention is applied to a shoe insole and this insole is used as a pressure sensor for a sole will be described. FIG. 1 (A) is a diagram showing a shoe SH to which the planar sensor of the present invention is applied, and FIG. 1 (B) is a diagram showing a planar sensor installed in the shoe SH. FIG. 2 is a diagram illustrating a configuration of the planar sensor illustrated in FIG.

  A planar sensor 1 shown in FIG. 1 (B) has a shape of an insole that can be used for the shoe SH shown in FIG. 1 (A), and a plurality of piezoelectric fibers 100 arranged in a net shape inside the insole. It is equipped with. In FIG. 1B, a plurality of piezoelectric fibers 100 provided in the surface sensor 1 are indicated by dotted lines. These piezoelectric fibers 100 are arranged along two directions intersecting at right angles, and the direction of this arrangement is a direction that obliquely intersects the longitudinal direction of the planar sensor 1. Hereinafter, these two orthogonal directions are referred to as a first direction and a second direction, respectively. In FIG. 1B, the longitudinal direction of the planar sensor 1, the first direction, and the second direction are indicated by arrows.

  The planar sensor 1 of the present embodiment is composed of four layers. Specifically, as shown in FIG. 2, the first layer 10 in which the piezoelectric fibers 100 are arranged along the first direction, and the second layer in which the piezoelectric fibers 100 are arranged along the second direction. In a state where the layers 11 are stacked, felt material layers 12 and 13 are provided on the upper and lower sides thereof. These layers are in a state of being bonded by an adhesive (for example, modified silicon, silylated urethane). Here, the first layer and the second layer are an example of a configuration in which the piezoelectric fibers 100 having different directions are not woven, and the felt material actually enters the gap between the piezoelectric fibers 100. . In addition, the piezoelectric fiber 100 along the second direction may be woven into the piezoelectric fiber 100 along the first direction to form a single layer, but the piezoelectric fiber 100 may be tensioned or planarized by weaving. In some cases, the pressure applied to the sensor 1 is concentrated at the intersection of the piezoelectric fibers 100 and a larger pressure is applied. For this reason, in the present embodiment, a configuration in which the piezoelectric fiber 100 along the first direction and the piezoelectric fiber 100 along the second direction are separated into different layers without being woven is adopted. In addition, when dividing into another layer, two or more layers may be sufficient.

  The piezoelectric fiber 100 of the planar sensor 1 is connected to the recording circuit 2 built in the side surface of the shoe SH, and the signal of the planar sensor 1 (induced voltage generated when the piezoelectric fiber 100 is deformed by pressure). Is recorded in a storage medium (for example, a flash memory) inserted in the recording circuit 2. By taking out this storage medium and analyzing the signal of the planar sensor 1, the position where the pressure applied to the sole changes can be determined. Note that the recording circuit 2 preferably uses a flexible substrate because it is built in the shoe SH. Further, the configuration is not limited to the configuration of the present embodiment. For example, the planar sensor 1 and an external processing device may be connected by wire or wirelessly, and a signal from the planar sensor 1 may be processed in real time.

  Next, the structure of the piezoelectric fiber 100 of the planar sensor 1 will be described with reference to FIGS. 3 is a cross-sectional view schematically showing the structure of the piezoelectric fiber 100 of the planar sensor 1, and FIG. 4 is a view showing the shape of the inner conductor of the piezoelectric fiber 100. As shown in FIG.

  As shown in FIG. 3, the piezoelectric fiber 100 has an inner conductor 101 composed of seven conductor wires 1000 at the center, a piezoelectric body 102 provided on the outer periphery thereof, and further provided on the outer periphery thereof. The outer conductor 103 is provided.

  The seven conductor wires 1000 each have a diameter of 10 μm, of which four are stainless steel conductor wires 1000S and the remaining three are copper conductor wires 1000C. In FIG. 3, the stainless steel conductor wire 1000 </ b> S is shown with a left-down hatching, and the copper conductor wire 1000 </ b> C is shown with a right-down hatching. In the inner conductor 101 shown in FIG. 3, a conductor wire 1000S (stainless steel wire) made of stainless steel is used for the conductor wire 1000 arranged in the center, and the conductor wire 1000 arranged on the outer periphery is made of stainless steel. The conductor wire 1000S and the copper conductor wire 1000C are used alternately. The copper conductor wire 1000C has a lower electrical resistance and is softer than the stainless steel conductor wire 1000S. On the contrary, the conductor wire 1000S made of stainless steel has higher electrical resistance but higher mechanical strength (for example, tensile strength) than the conductor wire 1000C made of copper.

  In FIG. 3, seven conductor wires 1000 are arranged at the apexes of the regular hexagon and the center of the regular hexagon, but these seven conductor wires 1000 are arranged as shown in FIG. It is the one twisted together. That is, the inner conductor 101 is formed by twisting together seven conductor wires 1000 arranged in a close-packed structure in the cross section. In this case, the maximum thickness of the inner conductor 101 is 30 μm. In this way, by twisting the plurality of conductor wires 1000 to the degree of sweet or medium twist, loosening in the direction opposite to the twisting direction is allowed, and this loosening gives the piezoelectric fiber 100 flexibility. be able to.

  The diameter of the conductor wire 1000 is not limited to 10 μm and may be 10 μm or more and 40 μm or less, and is preferably 20 μm or more and 30 μm or less. The thinner the conductor wire 1000, the higher the flexibility, but the lower the strength. The thicker the conductor wire 1000, the lower the flexibility but the strength. Moreover, if the thickness of the conductor wire 1000 is 20 micrometers or more, it can be manufactured at low cost and manufacture is also easy. Moreover, it is not restricted to the structure which makes the thickness of the conductor wire 1000 the same, You may comprise the internal conductor 101 by twisting the conductor wire 1000 of a different thickness.

  In addition, although the internal conductor 101 shown in FIG. 3 was the thing which twisted the seven conductor wires 1000, about this number, it does not need to be seven. Alternatively, for example, a plurality of bundles obtained by twisting a plurality of strands may be prepared, and these may be further twisted, and the strands may be twisted in a plurality of stages. By twisting the plurality of conductor wires 1000, the flexibility of the piezoelectric fiber 100 can be increased. In addition, when there are a plurality of twisting steps as in the case of twisting in a plurality of stages, the twisting directions may be varied. On the other hand, you may use what bundled the some conductor wire 1000 in the linear form, without twisting. Further, for example, these configurations may be combined such that a bundle of a plurality of conductor wires 1000 that are not twisted and a plurality of conductor wires 1000 that are twisted are twisted together. Even in these cases, by applying a piezoelectric material, a plurality of conductor wires 1000 can be bonded and bundled together to produce a single piezoelectric fiber.

  In the piezoelectric fiber 100 described above, a plurality of types of conductor wires having different mechanical strengths and electrical resistances are used as the conductor wires 1000 constituting the inner conductor 101. Is further lowered, the central conductor wire 1000 may be replaced with a copper conductor wire 1000C, or all of the seven conductor wires 1000 may be replaced with a copper conductor wire 1000C. On the contrary, when the mechanical strength is further increased, all of the seven conductor wires 1000 may be made of stainless steel conductor wires 1000S. Further, in place of the stainless steel conductor wire 1000S, a tungsten conductor wire, a conductor wire made of high-tensile steel such as tungsten and its alloys, or ultrahigh-tensile steel may be used, or the copper conductor wire 1000C may be used. Instead, a conductor wire made of titanium, a conductor wire made of titanium alloy, magnesium, magnesium alloy, or the like may be used.

  The piezoelectric body 102 is formed by applying a piezoelectric material such as polyvinylidene fluoride (PVDF) to the internal conductor 101. Polyvinylidene fluoride is a lightweight polymer material that generates a piezoelectric effect, and has a characteristic that a voltage is generated when a pressure is applied thereto, and a strain is generated when a voltage is applied thereto. The piezoelectric body 102 is subjected to polarization treatment, and a voltage is induced between the internal conductor 101 and the external conductor 103 when a force is applied to the piezoelectric body 102 from the outside. When a voltage is applied between the inner conductor 101 and the outer conductor 103, the piezoelectric body 102 is deformed (distorted).

  Examples of the piezoelectric material include polyvinylidene fluoride, trifluoroethylene (TrEF), a mixed crystal material of PVDF and TrEF, and a polymer material having a dipole moment such as polylactic acid, polyuric acid, and polyamino acid. . In addition, as a method of applying the piezoelectric material, it may be dipping (doughing) coating, spray coating by spray or the like, impregnation coating, or brush coating. Application by a coating device such as a coater may also be used. For example, a configuration in which a belt-like PVDF film is spirally wound around the internal conductor 101 may be used.

  The thickness of the piezoelectric body 102 is preferably equal to or larger than the diameter of the conductor wire 1000, and the thickness of the piezoelectric body 102 shown in FIG. 3 is 10 μm at the thinnest portion, but may be 10 μm or more and 50 μm or less. The sensor sensitivity becomes better as the thickness of the piezoelectric body 102 is larger, but the limit value of the thickness of the piezoelectric body 102 is determined by the viscosity of the piezoelectric material to be applied and the application method. In addition, if the thickness of the piezoelectric body 102 is too thick, the piezoelectric fiber 100 becomes too hard and lacks flexibility.

  In the internal conductor 101 shown in FIG. 3, since a plurality of conductor wires 1000 are twisted together, there is a depression at the boundary between the conductor wires 1000. In this recessed portion, more piezoelectric material can be carried, and the volume of the piezoelectric material becomes larger (thick), so that the sensor sensitivity becomes better than the other portions. Since the inner conductor 101 has six portions where the piezoelectric material is thicker than other portions due to such depressions, the inner conductor 101 functions as a highly sensitive piezoelectric fiber even if it is bent in any direction. It becomes a factor.

  Although the adjacent conductor wires 1000 shown in FIG. 3 are substantially in contact with each other, the piezoelectric material penetrates through a slight gap by capillary action, and the gap between the adjacent conductor wires 1000 (inside the inner conductor 101) is the piezoelectric material. It is in a state filled with. However, depending on the viscosity of the piezoelectric material and the application method, the piezoelectric material may not penetrate into the gap between the adjacent conductor wires 1000, but at least the portion facing the outer periphery of the inner conductor 101 is in a state where the piezoelectric material is supported. It only has to be.

  The outer conductor 103 shown in FIG. 3 is a layer formed by applying a polymer conductive material containing carbon such as carbon nanotubes to the outer periphery of the piezoelectric body 102. The conductive material forming the outer conductor 103 may be a polymer conductive material containing silver fine particles, a silver paste, or the like. In addition, the method for applying the conductive material may be immersion (dub coating) coating, spray coating by spraying, impregnation coating, or brush coating. It may be applied by a coating device such as a coater. The thickness of the outer conductor 103 is preferably less than or equal to the diameter of the conductor wire 1000, and is preferably less than or equal to the thickness of the piezoelectric body 102. The thickness of the outer conductor 103 shown in FIG. 3 is 5 μm, but may be 5 μm or more and 50 μm or less. Further, a conductive wire may be used for the outer conductor 103 without using a conductive material.

  As described above, the gap between the adjacent conductor wires 1000 in the inner conductor 101 is filled with the piezoelectric material, and there is no room for the polymer conductive material to enter.

  The piezoelectric fiber 100 shown in FIG. 3 is not provided with a sheath layer for improving wear resistance, chemical resistance, and rust resistance, but may be provided with this sheath layer. When the sheath layer is provided, it may be a single layer. For example, a sheath layer having a thickness of 6 μm may be applied twice to form a two-layer structure including an inner layer and an outer layer. In this case, the inner layer is formed by applying a soft material (for example, a polyamide synthetic resin or a polyvinyl chloride resin) as compared with the exterior, and the outer layer is a material (for example, a polytetracene) having higher wear resistance than the inner layer. Fluoroethylene (PTFE), tetrafluoride / hexafluoropropylene fluororesin (FEP), tetrafluoroethyleneethylene copolymer (EPFE), tetrafluoroethylene perfluoroalkoxyethylene copolymer fluororesin (PFA)) You may form by. The application referred to here may be immersion (doughing) coating, spray coating, brush coating, or coating by a coating device such as a coater. Moreover, it is preferable to apply several times in consideration of the occurrence of pinholes. Further, the outer layer may be thicker than the inner layer. Furthermore, the inner layer may be formed of a flammable material, but the outer layer is preferably formed of a flame retardant material, a non-flammable material, or a flame resistant material. The thickness of the entire sheath layer is preferably 5 μm or more and 50 μm or less. Furthermore, a polyester tape or a tube type sheath (both single layer and multiple layers) may be used, and the thickness may be 20 μm or more and 50 μm or less.

  The piezoelectric fiber 100 shown in FIG. 3 has a maximum thickness of 60 μm, and even if a sheath layer having a thickness of 10 μm is provided in a double structure, the piezoelectric fiber has a thickness of 0.1 mm. Here, as an example of the piezoelectric fiber 100 that is easy to manufacture and can be obtained at low cost, a piezoelectric material having a maximum thickness of 20 μm and an inner conductor 101 having a thickness of 60 μm using a conductor wire 1000 having a diameter of 20 μm. 102 and an outer conductor 103 having a thickness of 10 μm. In this configuration, the thickness up to the outer conductor 103 is 0.12 mm. Even if the sheath layer is provided in a double structure, the wire sensor 1 of 0.15 mm or less can be realized.

  Hereinafter, with reference to FIG. 5, the above-described planar sensor 1 of the present embodiment is compared with an embodiment in which the wiring direction of the piezoelectric fiber 100 is different from that of the present embodiment. One will be explained. FIG. 5A is a diagram illustrating the planar sensor 1 according to the present embodiment, and FIG. 5B illustrates an embodiment in which the wiring direction of the piezoelectric fiber 100 is different from that of the present embodiment (hereinafter referred to as the following). It is a figure which shows the planar sensor Z of a comparison object.

  In the sole, pressure is applied to the base part of the toe and the heel part, and pressure may be applied simultaneously to the plurality of parts during walking (or running). As an example, a case will be described in which pressure is applied simultaneously to the area A1 of the base of the toe shown in FIGS. 5A and 5B and the area A2 of the heel.

  In the planar sensor 1 of the present embodiment, as shown in FIG. 5 (A), five piezoelectric fibers along the first direction with respect to the pressure applied to the area A1 of the base part of the toe. Signals are detected from 100 (first group G1) and five piezoelectric fibers 100 (second group G2) along the second direction. Further, for the pressure applied to the region A2 of the heel portion, five piezoelectric fibers 100 (third group G3) along the first direction and five piezoelectric fibers along the second direction A signal is detected from 100 (fourth group G4). At this time, the intersection of the first group G1 and the second group G2 corresponds to the region A1, and the intersection of the third group G3 and the fourth group G4 corresponds to the region A2. In this case, the area where the pressure has changed can be determined by obtaining the intersection of the piezoelectric fibers 100 from which these signals are detected.

  On the other hand, in the planar sensor Z to be compared, as shown in FIG. 5 (B), the five piezoelectric fibers 100 along the longitudinal direction against the pressure applied to the area A1 of the base part of the toe are shown. Signals are detected from (fifth group G5) and five piezoelectric fibers 100 (sixth group G6) along the short direction. For the pressure applied to the region A2 of the heel portion, the five piezoelectric fibers 100 along the longitudinal direction (seventh group G7) and the five piezoelectric fibers 100 along the short direction (the first group G7). Eight groups G8) are detected. At this time, the intersection of the fifth group G5 and the sixth group G6 corresponds to the region A1, and the intersection of the seventh group G7 and the eighth group G8 corresponds to the region A2. Further, in the configuration of the surface sensor Z to be compared, in addition to the above, the intersection point can be obtained from the sixth group G6 and the seventh group G7, or the fifth group G5 and the eighth group G8. May include a region where no pressure is applied (for example, the intersection of the sixth group G6 and the seventh group G7, region A3, indicated by a dotted line).

  As described above, in the configuration of the surface sensor Z to be compared, there may be a case where a region where pressure is applied cannot be determined appropriately. The above problem is caused by the fact that the piezoelectric fiber 100 is provided in the longitudinal direction of the planar sensor Z, so that the range in which the single piezoelectric fiber 100 takes charge is widened. In view of this point, the present embodiment employs a configuration in which the piezoelectric fiber 100 is provided obliquely with respect to the longitudinal direction of the planar sensor 1. With this configuration, it is possible to narrow a range in which one piezoelectric fiber 100 is in charge, and it is possible to more accurately determine a position or a region where pressure is applied. For example, when detecting a change in the pressure of the sole and adopting a configuration in which a plurality of planar sensors are arranged on the sole of the shoe, it is difficult to match the positional relationship of these planar sensors However, such a problem does not occur when it is configured integrally as in this embodiment, so that installation can be performed easily.

  When a planar sensor is provided on the insole of the shoe as in this embodiment, the planar sensor bends in the longitudinal direction by walking or running. Here, when the planar sensor Z as shown in FIG. 5B is used, a force due to this bending is applied to the piezoelectric fiber 100 provided along the longitudinal direction, and the piezoelectric fiber 100 is to degrade. On the other hand, when the planar sensor 1 according to the present embodiment is used, the piezoelectric fiber 100 is provided obliquely with respect to the longitudinal direction, and therefore, the degree of bending is higher than that when wiring is performed along the longitudinal direction. It is possible to suppress the deterioration of the surface sensor 1.

  Next, using FIG. 6, the planar sensor 1 of the present embodiment shown in FIG. 5A and the planar sensor Z to be compared shown in FIG. 5B are shown again and wired externally. The difference will be described. FIG. 6A is a diagram showing the planar sensor 1 of the present embodiment, and FIG. 6B is a diagram showing the planar sensor Z to be compared shown in FIG. 5B.

  In providing wiring from the planar sensor 1 to the recording circuit 2, the present embodiment employs a configuration in which the piezoelectric fiber 100 inside the planar sensor 1 extends outside the planar sensor 1 and is connected to the recording circuit 2. Yes. Here, since the function of the piezoelectric fiber 100 as a sensor is unnecessary outside the planar sensor 1, this portion is heated (for example, at a heating temperature of 70 ° C. or higher and 150 ° C. or lower for 10 seconds or longer). The heating is performed for 10 minutes or less, preferably 80 ° C. or more and 120 ° C. or less for 10 seconds or more and 60 seconds or less.

  Furthermore, when the planar sensor 1 is applied to the insole of the shoe, it is necessary to bend the piezoelectric fiber 100 extending from the planar sensor 1 to the outside at the edge of the planar sensor 1. Here, as shown in FIG. 6B, when the piezoelectric fibers 100 are provided in the longitudinal direction and the short direction of the planar sensor Z, the piezoelectric fibers 100 are directly extended to the outside of the planar sensor Z. Then, many of the piezoelectric fibers 100 are perpendicular to the edge of the planar sensor Z. FIG. 6B shows an example of the piezoelectric fiber 100 extending outward at an angle substantially perpendicular to the edge of the planar sensor Z. When these bundles of piezoelectric fibers 100 are bent at the edge of the planar sensor Z, the angle becomes close to a right angle. On the other hand, as shown in FIG. 6A, when the piezoelectric fiber 100 is provided obliquely with respect to the longitudinal direction of the planar sensor 1, the piezoelectric fiber 100 is directly extended outside the planar sensor 1. Many of the piezoelectric fibers 100 are inclined with respect to the edge of the planar sensor 1. FIG. 6A shows an example of the piezoelectric fiber 100 that extends outward at an oblique angle with respect to the edge of the planar sensor 1. In this case, since the bundle of the piezoelectric fibers 100 can be bent at the edge of the planar sensor 1 without bending at a right angle, the degree of bending of the piezoelectric fibers 100 can be increased as compared with the case of FIG. Can be suppressed.

  The piezoelectric fiber 100 generates a signal when it is deformed by pressure, but depending on the installation situation, a signal may be generated by pressure other than the measurement target. Therefore, when providing the piezoelectric fiber 100, it is preferable to eliminate external force as much as possible. In this regard, in the configuration in which the piezoelectric fiber 100 is provided obliquely with respect to the longitudinal direction as in the planar sensor 1 of the present embodiment, wiring is performed in comparison with the case where wiring is performed along the longitudinal direction and the lateral direction. Therefore, the sensor performance of the planar sensor 1 can be improved.

  In the configuration described above, the example in which the planar sensor (planar sensor 1) in which piezoelectric fibers are arranged in a direction obliquely intersecting the longitudinal direction is applied to the shoe SH has been described. For example, as illustrated in FIG. The present invention can also be applied to detecting a change in pressure applied to a finger (or robot hand). FIG. 7A shows a planar sensor 1 for a finger of a hand, and FIG. 7B shows a state in which this is applied to the index finger of a hand HA. Thereby, the position where the pressure applied to the finger of the hand has changed can be determined more accurately. Further, as shown in FIG. 7A, since the piezoelectric fiber 100 protrudes obliquely from the planar sensor 1, it can be wired without applying a load from the back side of the finger to the wrist when applied. In addition, about this planar sensor 1, you may make it easily replaceable by comprising like a finger suck. In addition, in the case of detecting a change in pressure applied to the bed from the user, the same effect as described above can be obtained by using a planar sensor in which piezoelectric fibers are arranged obliquely intersecting the longitudinal direction. Can be obtained.

  In addition, when the installation surface of the planar sensor is hard and the piezoelectric fiber of the planar sensor is in direct contact with the installation surface, the piezoelectric fiber is not deformed by pressure, and the signal may not be detected. There is sex. In such a case, a buffer material is provided between the surface sensor and the installation surface so that the piezoelectric fiber can be deformed by pressure, or such a buffer material (for example, in FIG. It is preferable to provide a layer 13) of felt material.

  Hereinafter, other adoptable configurations will be described based on this embodiment.

  FIG. 8 is a diagram showing an embodiment in which the first direction and the second direction are different from those of the present embodiment. In the present embodiment, the first direction and the second direction are orthogonal to each other. For example, these directions may be inclined in the short direction as shown in FIG. Further, as shown in FIG. 8B, the degree of inclination with respect to the longitudinal direction may be different between the first direction and the second direction. Furthermore, you may provide the piezoelectric fiber 100 along the 3rd direction different from any of a 1st direction and a 2nd direction. In this case, since more information for specifying a region that has received pressure is increased, a more accurate position can be determined. In addition, about this 3rd direction, the same direction as a longitudinal direction may be sufficient, and a different direction may be sufficient. Further, when the piezoelectric fibers 100 are arranged along each of the first direction, the second direction, and the third direction, as shown in FIG. It is preferable not to intersect with each other (so that only two piezoelectric fibers 100 overlap each other at each intersection).

  Furthermore, the interval between the plurality of piezoelectric fibers 100 arranged along the first direction and the interval between the plurality of piezoelectric fibers 100 arranged along the second direction need not be the same interval, These intervals may be different. Further, for example, with respect to the plurality of piezoelectric fibers 100 arranged along the first direction, the interval may be increased for a non-important region. That is, the interval between the plurality of piezoelectric fibers 100 arranged along the first direction and the interval between the plurality of piezoelectric fibers 100 arranged along the second direction may not be constant. In addition, the direction of the piezoelectric fiber 100 may be shifted so long as it does not intersect with the adjacent piezoelectric fiber 100.

  Moreover, although the planar sensor 1 having a four-layer structure is shown in FIG. 2, this configuration is an example, and various forms can be applied to portions other than the piezoelectric fiber 100. Hereinafter, a configuration of the planar sensor 1 different from that in FIG. 2 will be described.

  FIG. 9 shows a planar sensor 1A in which a fiber 110 used for a general cloth or the like is arranged between piezoelectric fibers 100 arranged along the first direction and the second direction. Yes. FIG. 10 is a schematic view of the structure of the planar sensor 1A viewed from the side. In the following description, the fiber 110 sandwiched between the piezoelectric fibers 100 is referred to as a non-piezoelectric fiber 110 in order to distinguish it from the piezoelectric fiber 100.

  When a planar sensor using the piezoelectric fiber 100 is applied to a part touched by a person, the tactile sensation of the piezoelectric fiber 100 may be uncomfortable depending on the person. In view of these points, the planar sensor 1A shown in FIG. 9 is characterized in that the piezoelectric fiber 100 is sandwiched between non-piezoelectric fibers 110 that are thicker than the piezoelectric fiber 100 as shown in FIG. In addition, the piezoelectric fiber 100 and the non-piezoelectric fiber 110 are in a state of being woven and fixed by a weaving thread 111 thinner than these fibers. With this configuration, it becomes easier to touch the non-piezoelectric fiber 110 than the piezoelectric fiber 100, so that the chance of touching the piezoelectric fiber 100 is reduced and the tactile sensation is improved.

  For example, the non-piezoelectric fiber 110 preferably has a diameter of 0.3 mm to 1.2 mm. The material may be a synthetic fiber such as polyamide or rayon, may be a natural fiber such as cotton, or a material softer than the piezoelectric fiber 100 may be used. In addition, although the non-piezoelectric fiber 110 may be touched due to the pressure being crushed, the non-piezoelectric fiber 110 can be made thick to improve the tactile sensation.

  The weaving yarn 111 is preferably 1/5 or more and 1/3 or less of the diameter of the piezoelectric fiber 100. The material may be a synthetic fiber such as polyamide, polytetrafluoroethylene, polyester, or rayon, or may be a natural fiber such as cotton, or a material softer than the piezoelectric fiber 100 is used. It may be a thing.

  In the example of FIG. 9, two non-piezoelectric fibers 110 are arranged between the piezoelectric fibers 100. However, for example, two or more non-piezoelectric fibers may be arranged, or one non-piezoelectric fiber may be arranged. The number of the fibers 110 is not limited to this. Moreover, you may combine the some non-piezoelectric fiber 110 from which a raw material differs, and may combine the some non-piezoelectric fiber 110 from which thickness differs. In addition, the piezoelectric fiber 100 may be woven using part or all of the non-piezoelectric fiber 110 without using the woven yarn 111 in configuring the planar sensor 1A.

  In the above description, the example in which the tactile sensation is improved with the configuration of FIG. 9 has been described. For example, durability can be improved by using a metal fiber such as a stainless wire as the non-piezoelectric fiber 110.

  Moreover, as shown in FIG. 11, the 1st layer 10 in which the piezoelectric fiber 100 was arrange | positioned along the 1st direction, and the 2nd layer in which the piezoelectric fiber 100 was arrange | positioned along the 2nd direction In addition to 11, a third layer 14 of non-piezoelectric fibers 110 may be added to form the planar sensor 1B. 2 is an example in which the third layer 14 is made of a felt material. In this configuration, the third layer 14 may be fixed to the first layer 10 and the second layer 11 using fibers such as twisted yarns, or may be bonded.

  For example, the third layer 14 is formed of a synthetic fiber such as polyamide or rayon, or a natural fiber such as cotton, and the tactile sensation can be improved by overlapping the third layer 14 on a surface touched by a person. In this case, in the first layer 10 and the second layer 11, the non-piezoelectric fibers 110 may or may not be provided, but the non-piezoelectric fibers 110 made of the same material as that of the third layer 14 are used. In some cases, the tactile sensation can be further improved. At this time, since the first layer 10 and the second layer 11 are not touched by humans, the thickness of the non-piezoelectric fiber 110 does not have to be larger than that of the piezoelectric fiber 100 as shown in FIG.

  Further, for example, depending on the usage state of the surface sensor 1B, the surface sensor 1B may be damaged by wear. For such a situation, the third layer 14 is formed of a metal fiber such as a stainless steel wire, and this is overlaid on the outer surface of the planar sensor 1B, whereby the durability of the planar sensor 1B. Can be improved. In this case, in the first layer 10 and the second layer 11, the non-piezoelectric fiber 110 may or may not be provided, but the non-piezoelectricity by the metal fiber similar to the third layer 14 is provided. By providing the fiber 110, the durability may be further improved. At this time, since the first layer 10 and the second layer 11 do not touch the outside, the thickness of the non-piezoelectric fiber 110 does not have to be larger than that of the piezoelectric fiber 100 as shown in FIG. If the thickness is increased, the piezoelectric fiber 100 is less likely to be worn inside the planar sensor 1B, and the durability may be further improved.

  In the planar sensor 1, the piezoelectric fiber 100 is wired straight along the first direction or the second direction. However, it may not be straight, for example, it may be wired along the first direction or the second direction as a whole while locally drawing a regular arc. For example, as shown in FIG. 12, when adjacent piezoelectric fibers 100 are knitted, wiring can be performed along the first direction or the second direction as a whole while locally drawing a regular arc. . In this example, the piezoelectric fibers 100 are knitted together, but the piezoelectric fibers 100 and the non-piezoelectric fibers 110 may be knitted. In addition, when a water-soluble material is used for the non-piezoelectric fiber 110, only the piezoelectric fiber 100 is regularly twisted by melting the non-piezoelectric fiber 110 after the surface sensor 1 is formed. be able to. When the piezoelectric fiber 100 has a regular arc, the entire surface of the piezoelectric fiber 100 becomes flexible like a spring, so that the planar sensor 1 can be softened and easy to install even on a curved surface. Can do.

  In the example of FIG. 1, there is a possibility that the planar sensor 1 is displaced inside the shoe SH by walking or running. Also, when the planar sensor 1 is once removed from the shoe and installed again, the installation position may deviate from the previous position. As described above, the above-described planar sensor 1 may be displaced from the initial position during use or may be different in position each time it is used. When such a situation occurs, the analysis result is as if the pressure was received at a different position even though the pressure was received at the same position.

  In such a case, a positioning member capable of applying pressure directly or indirectly to a predetermined position on the installation surface is prepared, and a reference position for pressure detection may be determined using this. Good. For example, in the case of the example of FIG. 1, the reference position can be determined using the footboard 3 provided with the convex portion 30 with a size that matches the shape of the shoe sole of the shoe SH as shown in FIG. 13. . Specifically, when the foot plate 3 is stepped on in a state where the shoe SH is provided with the planar sensor 1 and the heel portion is aligned with the guide 31, pressure is generated on the sole at a position corresponding to the convex portion 30. Therefore, this position is set as the reference position. In determining the position from the signal detected when the planar sensor 1 is used, the positional deviation generated in the planar sensor 1 can be ignored by deriving the relative position with respect to the reference position. it can.

  Further, in the example of FIG. 1, the configuration in which the sole pressure is detected using one sheet sensor 1 is described, but a plurality of sheet sensors 1 can be used. For example, in addition to the shoe SH and the surface sensor 1 of FIG. 1, a surface sensor 1 ′ is separately prepared as shown in FIG. 14, and this is provided on the bottom surface of the shoe SH. It is possible to confirm how the surface sensor 1 ′) is transmitted to the sole of the foot. In other words, it can be said that the buffering performance by the portion sandwiched between the two planar sensors 1, 1 '(sole SO in the example of FIG. 14) can be seen. The position where the planar sensors 1, 1 'are provided may be embedded in the sole SO, for example, and is not limited to the above example. Moreover, although the above example is for shoes SH, for example, when the surface sensors 1 are provided above and below the mattress of the bed, the cushioning performance of the mattress can also be seen. Even when the sizes of the two planar sensors 1 and 1 'to be sandwiched are different or the density of the piezoelectric fiber 100 is different, the buffering performance by the sandwiched portion can be seen.

  When the positions of the pressures detected from the two planar sensors 1 and 1 ′ are aligned, a positioning member such as the tread plate 3 described with reference to FIG. 13 may be used. Note that the guide 31 may not be used when the positional relationship between the two planar sensors 1 and 1 ′ is grasped. Even when the guide 31 is not used, pressure is detected at the position of the convex portion 30 from each of the two planar sensors 1 and 1 ′. Can be adjusted (corrected).

  Note that, as in the example of FIG. 14, the planar sensor 1 ′ provided on the bottom surface of the shoe SH is a planar sensor whose durability is increased by the metal fiber described with reference to FIGS. 9 and 11. Is preferred.

  Further, the planar sensor 1 is not limited to the configuration in which only the piezoelectric fiber 100 is wired. For example, a configuration in which a conductive wire having no piezoelectricity is paired with the piezoelectric fiber 100 may be employed. In the planar sensor 1, noise may be superimposed on a signal from the piezoelectric fiber 100, but similar noise is also superimposed on a pair of conducting wires. Utilizing this, the output from the lead wire is such that the difference between the output of the piezoelectric fiber 100 and the lead wire becomes the lowest in a state where no pressure is applied to the planar sensor 1 (so that the mutual noise components are offset). In addition, the influence of noise can be reduced by taking the difference between the output of the piezoelectric fiber 100 and the conductive wire. Moreover, you may make a pair the conductor which has the same impedance as the piezoelectric fiber 100 so that the magnitude | sizes of both noise may become equal.

  In connecting the sheet sensor 1 and the recording circuit 2, the inner conductor 101 and the outer conductor 103 of the piezoelectric fiber 100 may be soldered. In this soldering, for example, the state shown in FIG. In FIG. 15, the substrate FL is hatched to the left, the land LA provided on the substrate FL is cross-hatched, and a cylinder SL (for example, tin or nickel on copper covering the end of the piezoelectric fiber 100). Are shown with hatching on the lower right.

  In the example of FIG. 15, the piezoelectric fiber 100 is passed from the front side (upper side in FIG. 15) to the back side (lower side in FIG. 15) through the first hole H <b> 1 provided in the substrate FL. Through the hole H2, the piezoelectric fiber 100 is passed from the back side to the front side, and the end portion is exposed to the front side. The piezoelectric fiber 100 is in a state in which the outer conductor 103 is exposed when passing through the first hole H1, and before passing through the second hole H2, the outer conductor 103 is removed and the piezoelectric body 102 is removed. Is exposed. The end portion of the piezoelectric fiber 100 is inserted into the cylinder SL in a state where the inner conductor 101 is folded back along the piezoelectric body 102 and is crimped.

  When the thin piezoelectric fiber 100 as described with reference to FIG. 3 is used, the internal conductor 101 may be cut during connection. On the other hand, the piezoelectric body 102 of the piezoelectric fiber 100 can protect the inner conductor 101. For this reason, it is preferable to leave the piezoelectric body 102 as much as possible, but on the other hand, since the solder is not attached to the piezoelectric body 102, it becomes an obstacle when the internal conductor 101 is connected. For this reason, as shown in the example of FIG. 15, by inserting and crimping the end of the piezoelectric fiber 100 in a state where the inner conductor 101 is folded back along the piezoelectric body 102 inside the cylinder SL, the inner conductor 101 is bonded. It is possible to prevent breakage and facilitate soldering. The cylinder SL may be inserted into the substrate FL after inserting and crimping the end of the piezoelectric fiber 100, or inserted and crimped after passing the end of the piezoelectric fiber 100 through the front side of the substrate FL. May be.

  Further, as shown in the configuration of FIG. 15, by passing the opposite surface of the substrate FL once and fixing the piezoelectric fiber 100, the piezoelectric fiber 100 can be firmly fixed and difficult to come off.

  Further, in the configuration of FIG. 15, the piezoelectric body 102 that is an insulator is exposed in a portion from the first hole H1 to the second hole H2. In this configuration, the outer conductor 103 soldered in the first hole H1 and the inner conductor 101 soldered in the second hole H2 can be reliably insulated.

  Further, a magnet may be arranged in advance on the substrate FL at a position where the piezoelectric fiber 100 is connected, and the piezoelectric fiber 100 may be made of a material containing a ferromagnetic material. In this configuration, the piezoelectric fiber 100 can be easily disposed at the connection position of the substrate FL, and the work efficiency and accuracy of soldering can be improved. The target to include the ferromagnetic material may be any of the inner conductor 101, the piezoelectric body 102, and the outer conductor 103. For example, the stainless steel conductor wire 1000S shown in FIG. 3 may be made of 400 series stainless steel (stainless steel in which chromium is mixed with 10.5% or more). Further, even if the piezoelectric fiber 100 is not made of a material containing a ferromagnetic material, for example, a member into which the end of the piezoelectric fiber 100 such as the cylinder SL in FIG. 15 can be inserted is made of a material containing a ferromagnetic material. By attaching this member to the end of the piezoelectric fiber 100, the piezoelectric fiber 100 can be easily disposed at the connection position of the substrate FL. Further, the arrangement of the magnets is not limited to the configuration in which the magnets are provided on the substrate FL itself. For example, the magnets are provided on a plate different from the substrate FL, and this plate is attached to the back side of the substrate FL (the piezoelectric fiber 100 is soldered) The magnet may be arranged at a position where the piezoelectric fiber 100 is connected on the substrate FL. In this configuration, after the piezoelectric fiber 100 is connected to the substrate FL, the plate on which the magnet is provided can be removed, so that the weight can be reduced compared to the configuration in which the magnet is provided on the substrate FL.

  In the piezoelectric fiber 100 described with reference to FIG. 3, the conductor wire 1000 is twisted to form the inner conductor 101, and then a piezoelectric material is applied to the inner conductor 101 to provide a piezoelectric body 102, and a polymer conductive material is further applied to the outer portion. A conductor 103 is provided. Regarding the twisting step in the manufacturing procedure, the piezoelectric fiber 100 can be manufactured even if the order is changed. Hereinafter, this will be specifically described with reference to FIG.

  For example, as shown in FIG. 16 (A), a piezoelectric material is applied to each of a plurality of conductor wires 1000 to provide a piezoelectric body 102, and then twisted together, and a polymer conductive material is applied thereto to apply externally. The conductor 103 may be provided to form the piezoelectric fiber 100A. Even in this configuration, each of the plurality of conductor wires 1000 functions as the internal conductor 101. In this example, the conductor wire 1000 has a diameter of 10 μm, the piezoelectric body 102 has a thickness of 10 μm, and the outer conductor 103 has a maximum thickness of 5 μm. Note that the number of twisted conductor wires 1000 provided with the piezoelectric body 102 and the method of twisting are the same as when the conductor wires 1000 shown in FIG. 3 are twisted together. Therefore, for example, the piezoelectric fiber 100A may be configured by applying the polymer conductive material to the conductor wires 1000 and bundling them with the external conductor 103 without providing the piezoelectric bodies 102 to each of the conductor wires 1000 and then binding them. .

  In the configuration of FIG. 16A, the diameter, number, and material of the conductor wire 1000 are the same as those of the piezoelectric fiber 100 shown in FIG. Further, the thickness, material, and sheath layer of the piezoelectric body 102 and the external conductor 103 are the same as those of the piezoelectric fiber 100 shown in FIG.

  In the configuration of FIG. 16A, the target for providing the piezoelectric body 102 is not limited to the single conductor wire 1000, and a plurality of conductor wires 1000 may be twisted or simply bundled.

  Further, adjacent conductor wires 1000 to which the piezoelectric material shown in FIG. 16A is applied are almost in contact with each other, but a slight gap is filled with the polymer conductive material. Depending on the viscosity of the polymer material and the coating method, this gap may not penetrate, but the polymer conductive material is supported on at least the portion facing the outer periphery of the bundle of conductor wires 1000 coated with the piezoelectric material. It only has to be. Further, as shown by a two-dot chain line in FIG. 16A, the polymer conductive material may be applied to such an extent that a gap between adjacent conductor wires 1000 to which the piezoelectric material is applied is filled.

  16A, the conductor wire 1000 has a diameter of 20 μm, the piezoelectric body 102 has a thickness of 20 μm, and the outer conductor 103 has a thickness of 10 μm. The thickness is about 0.2 mm. This piezoelectric fiber 100A is an example that can be easily manufactured at low cost.

  Further, for example, as shown in FIG. 16B, a piezoelectric material is applied to each of a plurality of conductor wires 1000 to provide a piezoelectric body 102, and a polymer conductive material is further applied to provide an external conductor 103. These may be twisted to form the piezoelectric fiber 100B. Even in this configuration, each of the plurality of conductor wires 1000 functions as the internal conductor 101. In this example, the conductor wire 1000 has a diameter of 10 μm, the piezoelectric body 102 has a thickness of 10 μm, and the outer conductor 103 has a maximum thickness of 5 μm. Note that the number of twisted conductor wires 1000 provided with the piezoelectric body 102 and the external conductor 103 and the way of twisting are the same as in the case of twisting the conductor wires 1000 shown in FIG. Accordingly, for example, the piezoelectric fiber 100B may be configured by bundling these with a sheath without providing the piezoelectric body 102 and the external conductor 103 to each of the plurality of conductor wires 1000 and then twisting them together.

  In the configuration of FIG. 16B, the target for providing the piezoelectric body 102 and the external conductor 103 is not limited to one conductor wire 1000, but a plurality of conductor wires 1000 twisted or simply bundled. Also good.

  16B, the conductor wire 1000 has a diameter of 20 μm, the piezoelectric body 102 has a thickness of 20 μm, and the outer conductor 103 has a thickness of 10 μm. The thickness is about 0.24 mm. This piezoelectric fiber 100A is an example that can be easily manufactured at low cost.

  16A and 16B, there are a plurality of portions in which the conductor wire 1000 is covered with the piezoelectric body 102 and the external conductor 103. For this reason, compared with the piezoelectric fiber 100 shown in FIG. 3, although the whole becomes thick, the reliability as a sensor can be improved.

  In addition, when a piezoelectric material is applied when manufacturing the piezoelectric fiber, there is a limit to the thickness of the piezoelectric material that can be applied depending on the viscosity of the piezoelectric material and the application method. Therefore, in the configuration of the piezoelectric fiber 100 in FIG. 3, it may be difficult to increase the sensor sensitivity by making the piezoelectric body 102 thicker. On the other hand, in the configuration of the piezoelectric fibers 100A and 100B in FIGS. 16A and 16B, even if the thickness of the piezoelectric fiber 100 and the piezoelectric body 102 in FIG. Therefore, sensor sensitivity can be improved.

  In FIG. 3 or FIG. 16, the configuration in which the piezoelectric material is applied once has been described, but the application may be performed a plurality of times. At this time, the piezoelectric material may be applied by combining (twisting or bundling) the conductor wires 1000 having different numbers of times of applying the piezoelectric material. As an example of this, in FIG. 17, four conductor wires 1000 coated with a piezoelectric material are arranged around one conductor wire 1000 not coated with a piezoelectric material, and a piezoelectric material is further coated on this bundle. The configuration is shown. In FIG. 17, the boundary between the first application and the second application is indicated by a dotted line. As described above, the sensor sensitivity and thickness can be adjusted according to the usage situation by combining the number and order of application, the twisting method and the bundling method.

  Further, as described above, the piezoelectric fiber 100 may have a configuration in which a band-shaped piezoelectric film (PVDF film) is spirally wound around the internal conductor 101 as the piezoelectric body 102. In the case of adopting this configuration, the width of the piezoelectric film is preferably 0.03 mm or more and 2 mm or less, and more preferably 0.05 mm or more and 1.0 mm or less. When the piezoelectric film is spirally wound around the peripheral surface of the inner conductor 101, a gap is created by overlapping one end and the other end of the adjacent piezoelectric film in the extending direction of the inner conductor 101. Do not.

  If the width of the piezoelectric film is too narrow, the piezoelectric films do not overlap each other when they are spirally wound around the outer peripheral surface of the internal conductor 101, and a gap is likely to occur. If there is such a gap, not only the portion where the piezoelectric body 102 that is deformed by the pressure is not provided and sensing becomes impossible, but the function as the pressure sensor is lost because the internal conductor 101 and the external conductor 103 are conducted. It will be. On the other hand, if the width of the piezoelectric film is too wide, slack is likely to occur when it is spirally wound around the peripheral surface of the internal conductor 101. Therefore, it is preferable to employ a piezoelectric film having an appropriate width.

  The thickness of the piezoelectric film is preferably 20 μm or more and 100 μm or less, and more preferably 25 μm or more and 80 μm or less. By superposing one end and the other end in the width direction of the piezoelectric film, the volume of the piezoelectric film can be increased, and the sensor sensitivity can be improved. At this time, if the thickness of the piezoelectric film is too thin, the sensitivity as the pressure sensor becomes insufficient. On the other hand, if the thickness is too thick, the piezoelectric fiber 100 becomes hard, and thus it is necessary to adjust according to the application. The piezoelectric film preferably has a piezoelectric property corresponding to a plurality of directions (elongation direction and bending direction) due to crystal orientation rather than that corresponding only to the longitudinal direction (elongation direction).

  Note that the number of piezoelectric films wound around the inner conductor 101 is not limited to one and may be plural. FIG. 18 shows a state in which two strip-shaped piezoelectric films 102F are wound in the same direction while being shifted by 180 degrees. When winding a single band-like piezoelectric film 102F, if tension is applied to the piezoelectric film 102F so that no slack occurs between the inner conductor 101 and the inner conductor 101, the inner conductor 101 is pulled in one direction. It is possible that the balance when wrapping is upset. However, when a plurality of strip-shaped piezoelectric films 102F are used as shown in FIG. 18, it is possible to prevent the films from being pulled in one direction by applying a uniform tension around the inner conductor 101.

  When the inner conductor 101 is formed by twisting the conductor wire 1000, the piezoelectric film 102F may be wound in the same direction as the twisting direction of the inner conductor 101, or may be wound in the opposite direction. . Depending on this direction, the flexibility of the piezoelectric fiber 100 may be increased.

  In addition to the above configuration, a planar sensor may be configured using, for example, a so-called piezoelectric film that is thinned into a fiber shape. That is, the piezoelectric fiber constituting the planar sensor may be a fiber having a structure in which a piezoelectric material is disposed between two insulated conductors (an inner conductor and an outer conductor) in a cross section intersecting the axial direction. .

  Although the planar sensor 1 having the shape of an insole for shoes has been described with reference to FIG. 1, it is conceivable to use different planar sensors 1 of different sizes depending on the size of the user's foot. Here, it may be preferable to eliminate the difference in foot size, for example, when comparing the pressure detection status in the planar sensor 1 or when the area for displaying the pressure detection status is determined. . In such a case, the ratio of enlargement / reduction in length and width is calculated so that the size of the planar sensor 1 becomes a predetermined size, and the detected coordinate of pressure is converted using this ratio (coordinates). Can be dealt with by normalizing.

[Placement of piezoelectric fiber]
Hereinafter, the arrangement of the piezoelectric fibers in the planar sensor will be described.

  When one piezoelectric fiber is used for detecting the pressure, it can be determined that the pressure is applied to the piezoelectric fiber based on the signal of the piezoelectric fiber. At this time, it is impossible to specify the position of the piezoelectric fiber where the pressure is applied.

  On the other hand, when two piezoelectric fibers are crossed, a signal is detected from either of the two piezoelectric fibers when pressure is applied to the intersection. For this reason, the position where the pressure was applied can be specified by arranging a plurality of piezoelectric fibers in a mesh shape and obtaining the intersection of the piezoelectric fibers from which signals are detected.

  Here, as shown in FIG. 19A, two piezoelectric fibers X1 and X2 are provided in the longitudinal direction, and two piezoelectric fibers Y1 and Y2 are provided in the transverse direction intersecting these. A case where pressure is simultaneously applied to the two points P1 and P2 will be described. In this case, signals are detected from a total of four piezoelectric fibers, that is, two vertical piezoelectric fibers X1 and X2 and two horizontal piezoelectric fibers Y1 and Y2. Here, in order to specify the position where the pressure is applied, when the intersection of the piezoelectric fibers from which these signals are detected is obtained, the two intersections P1, P2 where the pressure is actually applied and the two where the pressure is not applied are obtained. A total of four intersections of two intersections P3 and P4 are targeted. At this time, no matter which piezoelectric fiber signal is used, it becomes impossible to narrow down the intersection where the pressure is applied.

  The above problem occurs when piezoelectric fibers passing through two points under pressure also intersect at other points. However, such a problem does not occur when the number of other intersections is one or less. Here, with reference to FIG. 19B, a case where there is another intersection point P3 in the piezoelectric fibers X1, X2, Y1, and Y2 passing through the intersection points P1 and P2 to which pressure is applied will be described as an example. In this case, signals are detected from a total of four piezoelectric fibers, that is, two vertical piezoelectric fibers X1 and X2 and two horizontal piezoelectric fibers Y1 and Y2.

  Here, in order to specify the position where the pressure is applied, when the intersection of the piezoelectric fibers where these signals are detected is obtained, the two intersections P1, P2 where the pressure is actually applied and the intersection where the pressure is not applied A total of three intersections of P3 are targeted. Here, since the piezoelectric fiber X1 passes only the intersection point P1, it can be estimated from this signal that the pressure is applied to the intersection point P1. Moreover, since the piezoelectric fiber Y2 passes only the intersection point P2, it can be estimated from this signal that the pressure is applied to the intersection point P2.

  In the piezoelectric fiber Y1, a signal based on the pressure at the intersection point P1 and the intersection point P3 is output. However, the difference from the signal of the piezoelectric fiber X1 is caused by the pressure at the intersection point P3. In the piezoelectric fiber X2, a signal based on the pressure at the intersection point P2 and the intersection point P3 is output. However, the difference from the signal of the piezoelectric fiber Y2 is caused by the pressure at the intersection point P3. Based on these differences, it can be estimated whether or not pressure is applied to the intersection P3.

  Based on the above, in the case where a planar sensor is provided for two regions (hereinafter referred to as a first region and a second region) that are predicted to have a high frequency of pressure, FIG. It is preferable not to cause the problem described in (1). Specifically, for example, the piezoelectric elements are set so that the number of intersections between two piezoelectric fibers intersecting in the first region and two piezoelectric fibers intersecting in the second region is 1 or less. May be provided. For example, in FIG. 19B, the intersection point P1 intersects two piezoelectric fibers X1 and Y1 that intersect at an intersection point P1 corresponding to an example of the first region, and an intersection point P2 corresponding to an example of the second region. The number of intersections between the two piezoelectric fibers X2 and Y2 is 1 (only the intersection P3). Also, for example, two piezoelectric fibers that intersect in the first region do not pass through the second region, and two piezoelectric fibers that intersect in the second region do not pass through the first region. You may do it. At this time, the piezoelectric fiber is not limited to being wired straight, but may be bent and wired. The planar sensor 1 in FIG. 1 is long in the vertical direction of the drawing. However, in adopting the above configuration, a square or circular planar sensor having no longitudinal direction may be used.

  As an example of the above configuration, for example, with respect to a reference direction connecting the first region and the second region, a first direction obliquely intersecting the reference direction and a second direction obliquely intersecting the reference direction The structure which provided the piezoelectric fiber along each of these is mentioned. In this configuration, the number of intersections between the two piezoelectric fibers intersecting in the first region and the two piezoelectric fibers intersecting in the second region is unlikely to be two or more. The problem described in (A) hardly occurs. The planar sensor 1 shown in FIG. 1 can be said to be one to which the above configuration is applied, and the base part and the heel part of the toe where pressure is mainly applied correspond to the first region and the second region, The longitudinal direction of the planar sensor 1 corresponds to the reference direction. In this example, the longitudinal direction of the planar sensor 1 is adopted as an example of the reference direction, but it may be the longitudinal direction of the measurement target.

[Surface sensor with piezoelectric fibers in some areas]
The planar sensor 1 shown in FIG. 1 and other embodiments described so far detects that pressure has been applied to the entire planar sensor by disposing the piezoelectric fiber 100 over the entire surface. Is possible. On the other hand, when the pressure at a fixed position is to be detected, the piezoelectric fiber 100 may be provided at that position, and the piezoelectric fiber 100 may not be provided on the entire surface sensor. . This will be specifically described below.

  FIG. 21 (A) shows the sole of the right foot RF. For example, when standing upright, the ball B1, the little finger ball (place where the meat is raised near the base of the little finger) B2, and the thumb ball (place where the meat is raised near the base of the thumb) B3 It is known to support loads. Further, during running or walking, it is known that the load moves in the order of the eyelid B1, the little ball B2, the thumb ball B3, and the thumb B4. FIG. 21A shows the movement of this load. Is indicated by an arrow. In the following description, this load movement line is referred to as a load movement line.

  From the above, when analyzing and evaluating the posture when the subject is standing upright or when walking or running, the change in pressure applied to the heel B1, the little ball B2, the thumb ball B3, and the thumb B4 is measured. It can be said that it is important to see. For such applications, for example, as in the planar sensor 5 shown in FIG. 21B, the piezoelectric fiber 100 may be provided on the eyelid B1, the little finger ball B2, the thumb ball B3, and the thumb B4. Good. The planar sensor 5 shown in FIG. 21B is different from the planar sensor 1 of FIG. 1 in that the piezoelectric fiber 100 is arranged on a part of the planar sensor. Further, the planar sensor 1 of FIG. 1 has a configuration in which two layers of piezoelectric fibers 100 are stacked as shown in FIG. 2, but the planar sensor 5 shown in FIG. The difference is that it is a single layer. In FIG. 21B, the piezoelectric fibers 100 are provided in multiple circles in the heel B1, the little finger ball B2, the thumb ball B3, and the thumb B4. However, these piezoelectric fibers 100 are planar sensors. 5 is wired to the outside. In FIG. 21B, the portion indicated by the solid line in these piezoelectric fibers 100 is a portion having piezoelectric characteristics, and the other portions (portions omitted in the figure) are such that the piezoelectric characteristics cannot be detected. It is reduced by heat treatment. In this way, by partially reducing the piezoelectric characteristics of the piezoelectric fiber 100 with respect to other than the desired portion of the planar sensor 5, a portion having the piezoelectric characteristics can be left in the desired portion. Can be detected.

  In the example of FIG. 21B, since a signal is output when pressure is applied to the eyelid B1, the little ball B2, the thumb ball B3, and the thumb B4, the posture of the subject standing upright or walking using this signal is output. You can analyze and evaluate the form when traveling. Further, in the example of FIG. 21B, since a configuration in which the piezoelectric fiber 100 inside the circle and the piezoelectric fiber 100 outside the circle are different is adopted, whether or not pressure is applied to the center of the circle. Can be discriminated, and useful information can be provided in the above analysis and evaluation. In FIG. 21B, the piezoelectric fibers 100 are provided at four locations of the eyelid B1, the little finger ball B2, the thumb ball B3, and the thumb B4. Depending on the application, the piezoelectric fibers 100 may be provided at one location. 100 may be provided. Further, for example, the piezoelectric fiber 100 corresponding to the region of the base of the finger including these (region B5 in FIG. 21A) is provided without dividing the piezoelectric fiber 100 of the little ball B2 and the thumb ball B3. It is good also as a structure. In FIG. 21B, the piezoelectric fibers 100 are provided in a multi-circular shape, but may be, for example, a single circular shape or a spiral shape. They may be crossed and various wiring forms can be employed.

  In addition to the configuration of FIG. 21B, for example, a planar fiber 6 shown in FIG. 21C may be provided with a piezoelectric fiber 100 that intersects the load movement line with a gap. Good. The planar sensor 6 shown in FIG. 21C is different from the planar sensor 1 of FIG. 1 in that the piezoelectric fiber 100 is arranged on a part of the planar sensor. Further, in the planar sensor 1 shown in FIG. 1, two layers of piezoelectric fibers 100 are stacked as shown in FIG. 2, but the planar sensor 6 shown in FIG. The difference is that it is a single layer. In FIG. 21C, 13 piezoelectric fibers 100 are provided, and these piezoelectric fibers 100 are wired to the outside of the planar sensor 6. In FIG. 21C, a portion indicated by a solid line in these piezoelectric fibers 100 is a portion having piezoelectric characteristics, and the other portions (portions omitted in the drawing) cannot detect the piezoelectric characteristics. It is reduced by heat treatment. In this way, by partially reducing the piezoelectric characteristics of the piezoelectric fiber 100 with respect to other than the desired portion of the planar sensor 6, a portion having the piezoelectric characteristics can be left in the desired portion, and the pressure in this portion can be reduced. Can be detected.

  In the example of FIG. 21C, since a signal is output in accordance with the pressure that changes along the load movement line, it is possible to analyze and evaluate the form when the subject is walking and running. . In addition, there are individual differences in the load movement line, and it is conceivable that the load movement line is shifted in a direction perpendicular to this line. However, when such a shift occurs due to the provision of the piezoelectric fiber 100 so as to intersect the load movement line. But pressure can be easily detected. In FIG. 21C, 13 piezoelectric fibers 100 are provided. However, depending on the application, the number is not limited to this number, and the installation interval is limited to the interval shown in FIG. 21C. Is not to be done. The configuration in FIG. 21C is an example of the wiring of the piezoelectric fiber 100, and is not limited thereto, and various wiring forms can be employed.

  In addition, an audio output circuit that outputs audio based on a signal from the piezoelectric fiber 100 may be provided. In this case, the subject can be made aware of the state of pressure. For example, by assigning different sound to each of the piezoelectric fibers 100 of the planar sensor 5 in FIG. 21B and the planar sensor 6 in FIG. It can make it easier to grasp. Further, for example, when the piezoelectric fiber 100 is provided only in the portion of the thumb ball B3 shown in FIG. 21A and a sound is output in response to a signal from the piezoelectric fiber 100, this is used. By running with the consciousness of outputting sound, it can be used as an index for improving the form during driving. Such a simple index is particularly effective for children, for example.

  In addition, it is good also as a structure which provided the vibration circuit which generate | occur | produces a vibration based on the signal from the piezoelectric fiber 100 not only to an audio | voice, and to the structure combined with the audio | voice output circuit. Further, the configuration is not limited to a configuration that outputs sound. For example, a configuration in which BGM is normally output and the output of the BGM is reduced based on a signal from the piezoelectric fiber 100 may be employed. .

  In the example of FIG. 21 described above, the planar sensor for detecting the pressure change applied to the sole has been described, but the present invention is not limited to such a use. As an example, a case will be described in which a planar sensor for detecting a change in pressure applied to a mattress is configured. For mattresses, it is known that the pressure on the head, chest, waist, and legs is greater, and it can be said that it is important to look at changes in pressure on these areas. For this reason, the piezoelectric fiber 100 may be provided for each of these regions without providing the piezoelectric fiber 100 for the entire planar sensor as in the planar sensor 1 of FIG. Using this surface sensor, for example, the time during which pressure is applied due to the absence of a signal from any part is measured, and when this time exceeds a certain time, a voice or a lamp is used to inform a nurse or the like. Informing you can take action to prevent pressure ulcers. In addition, it is good also as a structure which provided the piezoelectric fiber 100 in one place among a head, a chest, a waist | hip | lumbar part, and a leg part depending on a use. In addition, about the structure which provides the piezoelectric fiber 100 in the part of the head part of a mattress, it can also be set as the structure which provided the piezoelectric fiber 100 in the pillow. Even when such a pillow is used, it is possible to measure the timing of going to bed and turning over, and this information can be used for treatment and care.

  Further, for example, a surface sensor may be applied to a mat used for an exercise such as yoga. In some exercises using a mat, a user maintains a specific posture for a certain period of time. At this time, a certain pressure is applied to a specific area of the mat. The pressure in the specific region does not change while the specific posture is maintained, and changes when the specific posture cannot be maintained. Therefore, the piezoelectric fiber 100 is provided in this specific region, and can be used as an index as to whether or not a specific posture is maintained based on a signal from the piezoelectric fiber 100. Note that, as described with reference to the planar sensor in FIG. 21, a sound may be output upon receiving a signal from the piezoelectric fiber 100 or vibration may be generated.

  In addition, there are individual differences in the user's body shape, and the position of a specific region is not fixed to one, so the piezoelectric fiber 100 is provided in a plurality of regions that are candidates for the specific region, and the user However, it is good also as a structure which uses this properly.

  In addition, about the planar sensor which provided the piezoelectric fiber in the one part area | region, unless it is consistent with the planar sensor which provided the piezoelectric fiber in the whole surface, the structure demonstrated in FIGS. 1-20 is applicable. .

[Pressure magnitude estimation]
The piezoelectric fiber generates an induced voltage when it is deformed by pressure, but no induced voltage is generated in a state where the pressure is maintained (a state in which no new deformation occurs). That is, the magnitude of the piezoelectric fiber signal cannot be used as an index indicating the magnitude of the pressure as it is. On the other hand, the amount of deformation of the entire piezoelectric fiber can be derived by integrating the signal from the piezoelectric fiber. Here, if pressure is applied to the same position of the piezoelectric fiber, the amount of deformation is proportional to the magnitude of the pressure, so the magnitude of the pressure can be estimated from the signal of the piezoelectric fiber. For example, in the planar sensor 5 shown in FIG. 21B, pressure is applied to each piezoelectric fiber at the same position (because the foot is fixed by shoes). Therefore, the surface sensor 5 can estimate the magnitude of the pressure from the signal of the piezoelectric fiber.

  Also, when estimating the pressure applied to the piezoelectric fiber from the piezoelectric fiber signal, the estimated value is compared with a previously stored pressure (hereinafter referred to as a reference pressure), and the difference is determined accordingly. It is good also as a structure which outputs an audio | voice. For example, when the objective is to take an ideal upright posture, the reference pressure is set with reference to measurement data obtained from a person having the ideal upright posture, theoretical pressure distribution, and the like. Next, the magnitude of the pressure when the user of the planar sensor 5 takes an upright posture is estimated and compared with the reference pressure. At this time, if the difference in pressure level exceeds a predetermined threshold, a sound is output, and if it is within the threshold, the sound is not output, so that the user can change his / her posture from the ideal upright posture. Misalignment can be recognized and can be used to improve posture. In FIG. 21B, the piezoelectric fibers 100 are provided at a plurality of locations of the planar sensor 5, but when setting a reference pressure for each of these piezoelectric fibers 100, sound is also generated. Different sounds may be set. In this case, the deviation from the ideal posture can be grasped more specifically.

  The configuration using the reference pressure as described above is not limited to the purpose of taking an ideal upright posture, and can be applied to various uses. For example, when exercising using a mat, it is difficult for the user himself to determine whether or not he is taking an ideal posture. For this reason, for example, by storing the magnitude of the pressure when taking an ideal posture under the instruction of the instructor as a reference pressure, even when there is no instructor, exercise can be performed using this as an index. Can do.

DESCRIPTION OF SYMBOLS 1 Planar sensor 100 Piezoelectric fiber 101 Inner conductor 102 Piezoelectric body 103 Outer conductor 1000 Conductor wire 2 Memory circuit 3 Footplate 5 Planar sensor 6 Planar sensor

Claims (8)

A planar sensor in which piezoelectric fibers are arranged,
The piezoelectric fiber has a reduced piezoelectric characteristic except for a part in the planar sensor.
A planar sensor characterized by the above. A planar sensor provided with a plurality of piezoelectric fibers provided for a first region and a second region that are predicted to have a high frequency of pressure,
In the piezoelectric fiber, the number of intersections between the two piezoelectric fibers intersecting in the first region and the two piezoelectric fibers intersecting in the second region is 1 or less. Is provided,
A planar sensor characterized by the above. A planar sensor in which a plurality of piezoelectric fibers are arranged in a net shape along each of a first direction and a second direction intersecting the first direction,
The first direction and the second direction are:
It is a direction that obliquely intersects the longitudinal direction of the planar sensor,
A planar sensor characterized by the above. The planar sensor according to any one of claims 1 to 3,
A planar sensor, wherein conductive wires are arranged adjacent to at least a part of the plurality of piezoelectric fibers. The planar sensor according to claim 4,
The planar sensor, wherein the conductive wire has the same impedance as that of the adjacent piezoelectric fiber. A planar sensor according to any one of claims 1 to 5,
A planar sensor, wherein a metal fiber layer is provided on a surface not in contact with an installation surface. A first planar sensor which is the planar sensor according to any one of claims 1 to 6;
A second planar sensor that is the planar sensor according to any one of claims 1 to 6,
In a state where the inspection object is sandwiched between the first planar sensor and the second planar sensor, the position of the pressure change in each of the first planar sensor and the second planar sensor is detected. A method of using a planar sensor characterized by the above. A method of using the planar sensor according to claim 7,
For position adjustment from the first planar sensor to the second planar sensor through the inspection object in a state where the inspection object is sandwiched between the first planar sensor and the second planar sensor Apply the pressure of
When the pressure for adjusting the position is applied, the position information of the pressure change is acquired in each of the first planar sensor and the second planar sensor,
A method of using a planar sensor, comprising correcting a positional relationship of pressure changes detected by the first planar sensor and the second planar sensor based on the positional information.