JP2023003244A - Capacitance sensor, and deformation detection system and method - Google Patents

Abstract

To provide a capacitance sensor that can measure deformation of a measurement object while preventing inhibition of the deformation of the measurement object.SOLUTION: A capacitance sensor 10 comprises: a sheet-like first conductive layer 11 that is arranged at a first end in a lamination direction and can be elastically deformed; a sheet-like second conductive layer 12 that is arranged at a second end in the lamination direction and can be elastically deformed; a sheet-like third conductive layer 13 that is arranged between the first conductive layer 11 and the second conductive layer 12 and can be elastically deformed; a sheet-like first insulating layer 14 that is arranged between the first conductive layer 11 and the third conductive layer 13 and can be elastically deformed; and a sheet-like second insulating layer 15 that is arranged between the second conductive layer 12 and the third conductive layer 13 and can be elastically deformed. The first conductive layer 11, third conductive layer 13, and first insulating layer 14 constitute a first capacitor 21, and the second conductive layer 12, third conductive layer 13, and second insulating layer 15 constitute a second capacitor 22.SELECTED DRAWING: Figure 4

Description

The present invention relates to a capacitive sensor, a deformation detection system and a deformation detection method.

As a capacitive sensor, a sensor is known in which a pair of sheet-shaped capacitors are stacked to detect bending based on changes in capacitance of the capacitors.

For example, in Patent Document 1, a pair of sheet-shaped capacitors are provided on one side and the other side in the stacking direction with respect to a reference member, and bending deformation is detected based on changes in capacitance of the pair of capacitors. A capacitive sensor is disclosed.

Japanese Patent No. 5496446

Among these types of capacitive sensors, in particular, when measuring changes in the shape of a living body, deformation of the measurement target is inhibited when the sensor is attached to the measurement target, such as skin or clothing. In order to suppress this, it is desirable to have flexibility (ease of elastic deformation) equal to or greater than that of the object to be measured.

In the capacitive sensor disclosed in Patent Document 1, since the pair of capacitors are stacked, the rigidity is higher and the flexibility is lower than when the capacitive sensor is composed of one capacitor. As a result, the object to be measured may feel restricted.

An object of the present invention is to provide a capacitive sensor capable of measuring deformation of a measurement target while suppressing inhibition of deformation of the measurement target.

A first aspect of the present invention is a first conductive layer disposed at a first end in the stacking direction and made of an elastically deformable sheet-like conductor;
a second conductive layer disposed at the second end in the stacking direction and made of an elastically deformable sheet-like conductor;
a third conductive layer disposed between the first conductive layer and the second conductive layer and made of an elastically deformable sheet-like conductor;
a first insulating layer disposed between the first conductive layer and the third conductive layer and made of an elastically deformable sheet-like insulating material;
a second insulating layer disposed between the second conductive layer and the third conductive layer and made of an elastically deformable sheet-like insulator,
A first capacitor is configured by the first conductive layer, the third conductive layer, and the first insulating layer,
A capacitive sensor is provided in which a second capacitor is formed by the second conductive layer, the third conductive layer, and the second insulating layer.

According to the present invention, since the capacitive sensor is configured such that the first capacitor and the second capacitor share the third conductive layer, when the first capacitor and the second capacitor are separately provided, Compared to , two members, the reference member and the conductive layer arranged on one side of the reference member, are not required, so the thickness of the capacitive sensor is reduced. As a result, the rigidity of the capacitive sensor is reduced, and the ability to follow the deformation of the object to be measured can be improved (inhibition of the deformation of the object to be measured is suppressed). Also, the cost can be reduced by reducing the number of members.

Furthermore, since the first capacitor and the second capacitor share the third conductive layer, for example, when measuring bending deformation from the difference in capacitance between the first capacitor and the second capacitor, the first capacitor Compared to the case where a reference member is provided between the capacitor and the second capacitor, it is easier to match the characteristics of the first and second capacitors and the variation of the capacitor is suppressed, so the cost for calibrating the variation of the capacitor can be reduced. .

In a state before deformation, the capacitance of the first capacitor and the capacitance of the second capacitor may be the same.

Since the deformation can be detected from the difference between the capacitance of the first capacitor after deformation and the capacitance of the second capacitor, the difference in capacitance between the first capacitor and the second capacitor before deformation can be detected. Then, the calculation of the deformation amount can be simplified. It is not necessary to obtain the change in capacitance of the first capacitor and the change in capacitance of the second capacitor before and after deformation.

The first conductive layer and the second conductive layer may be made of the same material.

According to this configuration, since the characteristics of the first capacitor and the second capacitor can be made to match, an increase in cost due to variations in the first capacitor and the second capacitor can be avoided.

An elongation rate of the conductive layer and the insulating layer may be set to 120% or more.

According to this configuration, it is possible to obtain followability to the measurement object.

A thickness in a stacking direction of the conductive layer and the insulating layer may be set to 0.5 mm or less.

According to this configuration, deformation of the object to be measured due to an excessive increase in rigidity of the capacitance sensor is less likely to be hindered.

The conductive layer has a surface resistivity of 100Ω/sq. May be set to:

According to this configuration, as the amount of the conductive filler compounded in the conductive layer increases, the contact between the conductive fillers increases, and the uneven distribution of electric charges in the conductive layer can be suppressed, thereby improving the measurement accuracy. can. Also, capacitive coupling between conductive fillers in the conductive layer is suppressed, and responsiveness and measurement accuracy can be ensured.

A dielectric constant of the insulating layer may be set to 3 or more.

According to this configuration, since the capacitance can be increased by increasing the dielectric constant, it is easy to measure the capacitance at the time of deformation, and to easily measure the deformation of the object to be measured.

A second aspect of the present invention is the capacitive sensor,
A deformation detection system comprising: a measurement unit that measures deformation based on changes in the capacitance of the first capacitor and changes in the capacitance of the second capacitor.

According to the present invention, the effects obtained with the capacitive sensor can also be obtained with the deformation detection system.

A third aspect of the present invention is a deformation detection method using the capacitive sensor,
calculating the amount of change in the capacitance of the first capacitor;
calculating the amount of change in the capacitance of the second capacitor;
There is provided a deformation detection method for detecting deformation based on respective amounts of change in capacitance of the first capacitor and the second capacitor.

According to the present invention, the effect obtained with the capacitance type sensor can also be obtained with the deformation detection method.

Advantageous Effects of Invention According to the present invention, it is possible to provide a capacitive sensor capable of measuring deformation of a measurement target while suppressing inhibition of deformation of the measurement target.

1 is a block diagram of a deformation detection system according to one embodiment of the present invention; FIG. FIG. 4 is a diagram for explaining a usage example of a capacitive sensor; 1 is a perspective view of a capacitive sensor according to one embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view of the capacitive sensor taken along line IV-IV in FIG. 3; FIG. 4 is a block diagram of a deformation detection system in a state where the capacitive sensor is convexly deformed; FIG. 4 is a block diagram of a deformation detection system in a state where the capacitive sensor is concavely deformed; 4 is a graph showing a comparison between actual measurement values during bending deformation and measurement values based on the amount of change in capacitance value for a capacitance sensor.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a deformation detection system 1 with a capacitive sensor 10 as one embodiment of the invention.

The deformation detection system 1 as a whole includes a bending-deformable capacitive sensor 10 . As shown in FIG. 2, the capacitive sensor 10, for example, is attached to the skin or clothes of the knee portion 91 (measurement target) of the human body 9, and the extension deformation (length) of the knee portion 91 is measured. and bending deformation (angle) are detected.

In the deformation detection system 1, extensional deformation (length) and bending deformation (angle) are measured as deformation amounts from the capacitance C detected by the capacitance type sensor 10 or the amount of change ΔC in the capacitance. ing. 1 to 6, the essential parts are exaggerated to make the structure of the capacitive sensor 10 easier to understand, and the dimensions and shapes of each member and each part are not shown accurately.

As shown in FIG. 3, the capacitive sensor 10 includes a first conductive layer 11 arranged at a first end (upper end in FIG. 3) in the stacking direction and made of an elastically deformable sheet-like conductor. , a second conductive layer 12 arranged at the second end (lower end in FIG. 3) in the stacking direction and made of an elastically deformable sheet-like conductor; A third conductive layer 13 made of an elastically deformable sheet-like conductor disposed between them, and an elastically deformable sheet-like insulation disposed between the first conductive layer 11 and the third conductive layer 13. and a second insulating layer 15 disposed between the second conductive layer 12 and the third conductive layer 13 and made of an elastically deformable sheet-like insulating material. Prepare.

The capacitive sensor 10 can be manufactured as follows. First, a hot melt sheet (not shown) for bonding the first to third conductive layers 11, 12, 13, the first and second insulating layers 14, 15, and the conductive layers and the insulating layers 11 to 15 ) are prepared.

Next, each conductive layer and each insulating layer 11 to 15 and the hot melt sheet are cut into a predetermined size, and each conductive layer and each insulating layer 11 to 15 are laminated in contact with each other (see FIG. 3). At this time, in this embodiment, a hot-melt sheet is sandwiched between each conductive layer and each insulating layer 11-15.

After that, from one side of the lamination direction of the laminated conductive layers and insulating layers 11 to 15 and the hot-melt sheet, the conductive layers and insulating layers 11 are heated while applying pressure with a thermocompression bonding machine or the like. 15 and the hot-melt sheet are adhered to complete the capacitive sensor 10 .

The first conductive layer 11, the first insulating layer 14, and the third conductive layer 13 form the first capacitor 21, and the second conductive layer 12, the second insulating layer 15, and the third conductive layer 13 form the second capacitor 22. It is The first capacitor 21 and the second capacitor 22 are laminated in the thickness direction.

The first to third conductive layers 11, 12, 13 and the first to second insulating layers 14, 15 are made of elastomer having elasticity and flexibility. It has elasticity so that it can be easily elastically deformed without interfering with the movement (deformation) of the human body when attached to the joints, back, chest, etc. of the human body to be measured.

For example, the elongation rate (elongation rate) of each conductive layer 11, 12, 13 and each insulating layer 14, 15 is set to 120% or more. Specifically, for example, urethane rubber, acrylic rubber, silicon rubber, butadiene rubber, nitrile rubber, chlorosulfonated polyethylene rubber, and natural rubber are used as elastic and flexible elastomers. The elongation rate is the ratio of the elongation between the marked lines on the test piece and the distance between the marked lines until each conductive layer and each insulating layer (test piece) breaks in the tensile test. Further, for example, when measuring the human body, it is preferable that the conductive layers 11, 12, 13 and the insulating layers 14, 15 have high flexibility, and the elastic modulus (Young's modulus) that can be replaced with flexibility is 120 MPa. It is set below.

The material of each conductive layer 11, 12, 13 and each insulating layer 14, 15 is not limited to this, and the cross-sectional shape, cross-sectional area, and length of each conductive layer 11, 12, 13 and each insulating layer 14, 15 The characteristics of bending deformation can be set in consideration of specific shapes such as. For example, depending on the muscle strength of the human body to be measured and the part to be worn, the material can be appropriately set in consideration of durability and ability to follow deformation.

As shown in Fig. 2, when measuring the bending deformation of the knee portion to be measured, in order to improve the detection sensitivity of the deformation of the knee portion, a thin constant cross-section having a predetermined width is used in the longitudinal direction (Fig. 2). 2) is preferably a substantially rectangular strip extending in the vertical direction. The film thickness (thickness in the stacking direction) of each of the conductive layers 11, 12, 13 and each of the insulating layers 14, 15 is set to 0.5 mm or less so that bending deformation of the knee portion is not hindered by the rigidity of the capacitance sensor 10. is set.

Here, assuming that the area of the conductive layer is S, the distance between the conductive layers (=the thickness of the insulating layer) is d, and the dielectric constant of the insulating layer is ε, there is a relationship of capacitance C=ε·(S/d). As the distance d between the conductive layers decreases, the capacitance increases, and as the distance d between the conductive layers increases, the capacitance decreases. As the area S of the conductive layer increases, the capacitance increases, and as the area S of the conductive layer decreases, the capacitance decreases. The dielectric constant of each of the insulating layers 14 and 15 is set to 3 or more to improve detection accuracy.

As described above, each of the conductive layers 11, 12, 13 is made of elastomer. In order to impart conductivity, an elastomer composition made of a mixture with a conductive filler composed of fine particles of carbon materials, metals, etc. is used. formed by As the conductive filler, for example, silver powder or carbon powder is adopted. , 13 is 100%, the conductive filler is mixed with the elastomer material in an amount of 10 to 70% or less.

In order to improve the detection accuracy, it is preferable to match the capacitances of the first capacitor 21 and the second capacitor 22 before deformation. At least the first conductive layer 11 and the second conductive layer 12 are composed of the same material and blending amount. For example, when the conductive filler of the first conductive layer 11 and the second conductive layer 12 is made of a carbon material, and the conductive filler of the third conductive layer 13 is made of a highly conductive metal material (for example, silver), it is expensive and conductive. While minimizing the highly conductive filler, the capacitance of the first capacitor 21 and the second capacitor 22 are matched, and the accuracy is easily improved compared to the case where the conductive filler of the carbon material is used for each conductive layer. .

The electric resistance (surface resistivity) of each of the conductive layers 11, 12, and 13 is set to 100 Ω/sq in order to ensure detection accuracy by suppressing uneven distribution of electric charges in the conductive layers due to an increase in surface resistivity. . It is desirable that: Also, by suppressing capacitive coupling between the conductive fillers in the conductive layer, responsiveness and measurement accuracy can be improved.

Next, movement of the capacitive sensor 10 when the capacitive sensor 10 is bent and deformed will be described with reference to FIG.

As shown in FIG. 4B, when the capacitive sensor 10 is bent and deformed so that one surface of the first conductive layer 11 or the second conductive layer 12, for example, the first conductive layer 11 becomes convex, The surface of the first conductive layer 11 is curved convexly, and the surface of the second conductive layer 12 is curved concavely. At this time, when the neutral plane of bending is within the thickness of the third conductive layer 13, the convexly curved first conductive layer 11 and the first insulating layer 14 are curved with respect to the third conductive layer 13. A tensile force (arrow A1) is applied from the center toward the periphery, and the layer is deformed so that the layer thickness becomes relatively thin.

On the other hand, the second conductive layer 12 and the second insulating layer 15 curved in a concave shape are relatively thickened and the surface area is reduced by a compressive force (arrow A2) acting from the periphery toward the curved bottom. Transform into As a result, while the capacitance C1 of the first capacitor 21 increases, the capacitance C2 of the second capacitor 22 decreases, so bending can be detected based on this capacitance change.

On the other hand, when the electrostatic sensor is curved and deformed so that the first conductive layer 11 becomes concave as shown in FIG. As in the case of bending deformation, bending can be detected based on changes in capacitance. When the capacitive sensor 10 is curved and deformed such that the first conductive layer 11 is concave, the second conductive layer 12 is curved convex.

At this time, when the neutral plane of bending is within the thickness of the third conductive layer 13, the concavely curved first conductive layer 11 and the first insulating layer 14 are curved from the periphery when the third conductive layer 13 is used as a reference. A compressive force (arrow B1) acts toward the bottom portion, and the second conductive layer 12 and the second insulating layer 15 are deformed so that the layer thickness becomes relatively thicker and the surface area decreases, and the curved second conductive layer 12 and the second insulating layer 15 curve. A tensile force (arrow B2) acts from the top toward the periphery and deforms such that the layer thickness becomes relatively thin and the surface area increases. As a result, while the capacitance C1 of the first capacitor 21 decreases, the capacitance C2 of the second capacitor 22 increases, so bending can be detected based on this capacitance change.

Also, the bending angle is calculated based on the difference (ΔC=C1-C2) between the capacitances (C1, C2) that change when the first and second capacitors 21, 22 laminated in the thickness direction are bent and deformed. may For example, it is possible to calculate the bending angle based on a predetermined function with a previously obtained capacitance difference ΔC as a variable, or to obtain the bending angle based on an angle table set in advance corresponding to the capacitance difference ΔC. can. The predetermined function can be a linear function if the capacitance difference ΔC is calibrated using the bend angle of the object measured by motion capture using a camera to track the position of the marker.

As for the capacitances (C1, C2) that change when the first and second capacitors 21, 22 are bent and deformed, the capacitance on the convexly curved side is larger than the capacitance on the concavely curved side. Therefore, the bending direction can be identified by the positive or negative of the difference (ΔC=C1−C2) between the capacitances (C1, C2) that change when the first and second capacitors 21, 22 are bent. When the difference ΔC between the capacitances (C1, C2) is positive, the first capacitor 21 side is curved and deformed in a convex shape, and when the difference ΔC between the capacitances (C1, C2) is negative, the first capacitor 21 is deformed. It can be determined that the capacitor 21 side is curved and deformed concavely.

Although the case where the neutral plane of bending is located within the thickness of the third conductive layer 13 has been described, the bending and / Or the bend angle can be detected. For example, when the neutral plane is located outside the second conductive layer 12 in the stacking direction and the first conductive layer 11 deforms convexly and the second conductive layer 12 deforms concavely, the first conductive layer 11 , the first insulating layer 14, the second conductive layer 12, and the second insulating layer 15 are deformed so that the film thickness becomes thinner than the state before deformation due to the tensile force acting from the top of the curve toward the periphery.

Therefore, the capacitance C1 of the first capacitor 21 and the capacitance C2 of the second capacitor 22 are both larger than the capacitance before deformation, but the first capacitor 21 is located on the convex side of the second capacitor 22. , the capacitance C1 of the first capacitor 21 becomes larger than the capacitance C2 of the second capacitor 22 because it is stretched thinner. As a result, the bending direction and angle can be detected based on the magnitude of the positive/negative value and the absolute value of the difference (ΔC=C1−C2) between the capacitances (C1, C2) as described above.

FIG. 1 shows a block diagram showing an example of a signal processing circuit of a deformation detection system 1. As shown in FIG. The deformation detection system 1 detects, for example, an AC power supply 41 that outputs a reference voltage Vs as a rectangular wave signal of about 1 kHz to the capacitors 21 and 22, and the difference ΔC between the capacitances C1 and C2 of the first capacitor 21 and the second capacitor 22. A calculation unit 42 for calculating, a calculation unit 43 for calculating the bending angle and direction based on the capacitance difference ΔC calculated by the difference unit 42, and a display unit 44 for displaying the bending angle calculated by the calculation unit 43. and

The difference unit 42, the calculation unit 43, and the display unit 44 constitute a measurement unit 40 that measures deformation based on changes in the capacitance C1 of the first capacitor 21 and changes in the capacitance C2 of the second capacitor 22. .

A reference voltage Vs output from the AC power supply 41 is applied to the first conductive layer 11 and the second conductive layer 12, and the third conductive layer 13 is grounded. In the difference part 42, the voltage V1 of the first capacitor 21 (the potential difference between the first conductive layer 11 and the third conductive layer 13) and the voltage V1 of the second capacitor 22 (the second conductive layer 12 and the third conductive layer 13 potential difference) V2 is input. Since the capacitance is proportional to the time-integrated value of the voltage waveform of the capacitor, the difference unit 42 calculates the difference ΔC between the capacitances C1 and C2 of the first capacitor 21 and the second capacitor 22 by using the reference voltage waveform A difference ΔV between the time integral values of V1 and V2 is calculated.

Specifically, output voltage waveforms V1 and V2 distorted with respect to the reference voltage Vs are output from the first capacitor 21 and the second capacitor 22 due to the resistance of the respective capacitors. As shown in FIG. 1, when the capacitive sensor 10 is in a state before deformation, the capacitances of the first capacitor 21 and the second capacitor 22 are set to match. 22 output voltage waveforms V1 and V2 match. Therefore, the difference ΔV between the time integral values of the output voltage waveforms of the first capacitor 21 and the second capacitor 22 calculated by the difference unit 42 becomes zero, and no deformation is detected.

As shown in FIG. 5, when the first capacitor 21 side of the capacitive sensor 10 is curved and deformed to be convex, the capacitance C1 of the first capacitor 21 is larger than the capacitance C2 of the second capacitor 22. As a result, the output voltage waveform V1 of the first capacitor 21 becomes relatively larger than the output voltage waveform V2 of the second capacitor 22 . Therefore, the difference ΔV between the time-integrated values of the output voltage waveforms of the first capacitor 21 and the second capacitor 22 calculated by the difference unit 42 is positive, and the first capacitor 21 side is deformed into a convex shape. is detected.

As shown in FIG. 6, when the first capacitor 21 side of the capacitive sensor 10 is curved and deformed into a concave shape, the capacitance C1 of the first capacitor 21 is smaller than the capacitance C2 of the second capacitor 22. Therefore, the output voltage waveform V1 of the first capacitor 21 becomes relatively smaller than the output voltage waveform V2 of the second capacitor 22. Therefore, the difference ΔV between the time-integrated values of the output voltage waveforms of the first capacitor 21 and the second capacitor 22 calculated by the difference unit 42 becomes negative, and the first capacitor 21 side is deformed into a convex shape. is detected.

The calculation unit 43 calculates the bending deformation angle based on the calculated difference ΔV between the time integral values of the output voltage waveforms and a predetermined function or table, and the calculated angle is displayed on a display or the like as the display unit 44. to be displayed.

As shown in FIG. 2, when the capacitive sensor having such a structure is worn on the human body, it is bent and deformed as the knee portion bends. The capacitive sensor 10 bends and deforms as the knee portion changes due to the movement of the portion. The capacitive sensor 10 is attached so that the stacking direction is the front-rear direction of the human body, and the capacitive sensor 10 is bent and deformed with a radius of curvature perpendicular to the length direction of the capacitive sensor 10 .

In addition, the capacitive sensor 10 is elastically deformed into an arc shape by the action of an external force accompanying a change in the posture of the human body (flexion of the knee), and a bending moment is generated at both ends in the length direction. It's becoming Specifically, as shown in FIG. 2, both ends P1 and P2 in the length direction of the bending deformation region over the entire length L functioning as a sensor are used as input points, so that the center point in the length direction P0 is set so as to substantially coincide with the knee portion 91, which is the bending point.

Specifically, in clothing worn in close contact with the surface of the human body, one end P1 of the capacitive sensor 10 arranged to extend across the knee portion P0 along the body side is fixed to the thighbone side. In addition, since the other end P2 is fixed to the tibia side, a bending moment acts on the entire capacitive sensor 10 through both ends P1 and P2 of the capacitive sensor 10 when the knee portion 91 is bent.

As a result, the knee portion is bent forward as shown in FIG. 2(b) from the extended state shown in FIG. 2(a). , arcuate curvature occurs between both ends P1 and P2. The curvature radius R of this curved state is a value corresponding to the bending angle θ of the knee portion 91 .

As described above, the deformation detection system 1 detects the capacitance of the capacitance sensor 10 attached to the object to be measured, and detects the static capacitance of the capacitance sensor 10 that undergoes bending deformation as the object to be measured bends. By obtaining the amount of change in capacitance from the initial shape, the bending angle θ of the capacitance type sensor 10 can be calculated from the amount of change in capacitance.

In the present embodiment, the center point P0 in the longitudinal direction of the capacitive sensor 10 is set to coincide with the knee portion 91, but the present invention is not limited to this. and the curvature of the measured portion. Specifically, it is sufficient that the capacitive sensor 10 is attached while sufficiently straddling the knee portion 91 .

FIG. 7 shows the bending deformation angle of the knee portion and the detection value of the amount of capacitance change actually measured by motion capture when the capacitive sensor 10 of the present embodiment shown in FIG. 1 is attached to the knee portion of the human body. and is a graph showing. In this graph, the horizontal axis represents time (s), and the vertical axis represents the bending deformation angle and capacitance variation. The broken line indicates the bending deformation angle of the knee portion actually measured by motion capture, and the solid line indicates the detected value of the amount of capacitance change.

For each insulating layer, an elastomer sheet having a thickness of about 0.1 mm, a dielectric constant of 5, and an elongation of 100% was used. Each conductive layer is made of elastomer with a thickness of about 0.1 mm and a surface resistivity of 1 Ω/sq. , an elongation rate of 100% and a conductive filler content of 50 to 60% by mass.

From the experimental results shown in the graph of FIG. 7, it can be seen that the displacement detection system 1 provided with the capacitive sensor 10 of the present invention can accurately detect deformation of the human body.

With the above configuration, according to the present invention, the capacitive sensor 10 is configured such that the first capacitor 21 and the second capacitor 22 share the third conductive layer 13, so the first capacitor 11 and the second capacitor 12 are separately provided, the thickness of the capacitive sensor 10 is reduced because the two members, the reference member and the conductive layer arranged on one side of the reference member, are not required. do. As a result, the rigidity of the capacitive sensor 10 is reduced, and the ability to follow the deformation of the object to be measured can be improved. (It is possible to prevent the deformation of the object to be measured from being obstructed.) Also, the cost can be reduced by reducing the number of members.

Furthermore, since the first capacitor 21 and the second capacitor 22 share the third conductive layer 13, when measuring bending deformation from the difference in capacitance between the first capacitor 21 and the second capacitor 22, Compared to the case where a reference member is provided between the first capacitor 21 and the second capacitor 22, it is easier to match the characteristics of the first and second capacitors 21 and 22, and variations in the capacitors 21 and 22 are suppressed. The cost of calibrating 21,22 variations can be reduced.

Since the capacitance C1 of the first capacitor 21 and the capacitance C2 of the second capacitor 22 are set to be the same in the state before deformation, the capacitance of the first capacitor 21 after deformation is Since the deformation can be detected from the difference ΔC between C1 and the capacitance C2 of the second capacitor 22, compared to the case where there is a difference in capacitance between the first capacitor 21 and the second capacitor 22 before deformation, deformation Quantity calculation can be simplified. It is not necessary to obtain the amount of change in the capacitance of the first capacitor 21 and the amount of change in the capacitance of the second capacitor 22 before and after deformation.

Since the first conductive layer 11 and the second conductive layer 12 are made of the same material, it is easy to match the characteristics of the first capacitor 21 and the second capacitor 22. An increase in cost due to variations can be avoided.

Since the elongation rate of each of the conductive layers 11, 12, 13 and each of the insulating layers 14, 15 is set to 120% or more, good followability to the object to be measured can be obtained.

Since the thicknesses of the conductive layers 11, 12, 13 and the insulating layers 14, 15 are set to 0.5 mm or less, the rigidity of the capacitive sensor 10 does not hinder deformation of the object to be measured.

The surface resistivity of each conductive layer 11, 12, 13 is 100Ω/sq. Since it is set as follows, the more the amount of the conductive filler blended in the conductive layer, the more the contact between the conductive fillers increases, and the uneven distribution of the electric charge in the conductive layer is suppressed, improving the measurement accuracy. can improve. Also, capacitive coupling between the conductive fillers in the conductive layer is suppressed, and responsiveness and measurement accuracy can be ensured.

Since the dielectric constant of each of the insulating layers 14 and 15 is set to 3 or more, the capacitance can be increased by increasing the dielectric constant. It is easy to measure the deformation of

Although the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments.

In the embodiment, the capacitances of the first capacitor 21 and the second capacitor 22 before deformation are the same, and the capacitances (C1, C2 ), the bending angle is calculated based on the difference (ΔC=C1−C2), but the present invention is not limited to this.

For example, there may be a difference in capacitance between the first capacitor 21 and the second capacitor 22 before deformation. In this case, the capacitances C10 and C20 before deformation, which are set in advance according to the specifications of the capacitors 21 and 22, are subtracted from the capacitances (C1 and C2) of the first and second capacitors 21 and 22 at the time of deformation. Bending may be detected from the difference (ΔC1-ΔC2) of the amount of change (ΔC1=C1-C10, ΔC2=C2-C20).

In addition, in the present embodiment, as a method for manufacturing the capacitive sensor 10, a configuration has been described in which each conductive layer and each insulating layer are cut into a predetermined size in advance and then thermocompression bonded, but the present invention is not limited to this. Absent. For example, ready-made conductive layers and insulating layers may be stacked and thermocompressed, and then cut into a predetermined size.

In addition, in the present embodiment, as the manufacturing method of the capacitive sensor 10, a configuration using a hot-melt sheet for adhering each conductive layer and each insulating layer has been described, but it is not limited to this. . For example, each conductive layer and each insulating layer may be laminated in an unvulcanized state and pressed under predetermined conditions to be vulcanized and bonded. In this case, each conductive layer and each insulating layer may be adhered by mutual adhesive strength without using a hot-melt sheet.

Further, for example, it is possible to laminate the insulating layer 13 and the pair of conductive layers 11 and 12 constituting the capacitive sensor 10 in multiple layers, thereby increasing the amount of change in the capacitance and improving the measurement accuracy. can also

In the embodiment, the present invention is applied to the deformation detection system 1 having the capacitive sensor 10 for detecting deformation of the knee portion, but the present invention is not limited to this, and can be applied to the back portion, shoulders, elbows. , chest, hip joint, etc., as the capacitive sensor 10 for detecting deformation of the human body.

As described above, according to the present invention, it is possible to provide a capacitive sensor capable of measuring the deformation of the object to be measured while suppressing the deformation of the object to be measured. There is a possibility that it will be suitably used in the field of related industries.

1 deformation detection system 10 capacitive sensor.
11 first conductive layer 12 second conductive layer 13 third conductive layer 14 first insulating layer 15 second insulating layer and 21 first capacitor 22 second capacitor

Claims (9)

a first conductive layer disposed at a first end in the stacking direction and made of an elastically deformable sheet-shaped conductor;
a second conductive layer disposed at the second end in the stacking direction and made of an elastically deformable sheet-like conductor;
a third conductive layer disposed between the first conductive layer and the second conductive layer and made of an elastically deformable sheet-like conductor;
a first insulating layer disposed between the first conductive layer and the third conductive layer and made of an elastically deformable sheet-like insulating material;
a second insulating layer disposed between the second conductive layer and the third conductive layer and made of an elastically deformable sheet-like insulator,
A first capacitor is configured by the first conductive layer, the third conductive layer, and the first insulating layer,
A capacitive sensor, wherein a second capacitor is composed of the second conductive layer, the third conductive layer, and the second insulating layer. In the state before deformation,
2. The capacitive sensor according to claim 1, wherein the capacitance of said first capacitor and the capacitance of said second capacitor are the same. 3. The capacitive sensor according to claim 1, wherein the first conductive layer and the second conductive layer are made of the same material. 4. The capacitive sensor according to any one of claims 1 to 3, wherein the elongation rate of said conductive layer and said insulating layer is set to 120% or more. 5. The capacitive sensor according to any one of claims 1 to 4, wherein the conductive layer and the insulating layer have a thickness of 0.5 mm or less in the stacking direction. The conductive layer has a surface resistivity of 100Ω/sq. The capacitive sensor according to any one of claims 1 to 5, set forth below. 7. The capacitive sensor according to any one of claims 1 to 6, wherein the insulating layer has a dielectric constant of 3 or more. a capacitive sensor according to any one of claims 1 to 7;
A deformation detection system comprising: a measurement unit that measures deformation based on changes in the capacitance of the first capacitor and changes in the capacitance of the second capacitor. A deformation detection method using the capacitive sensor according to any one of claims 1 to 8,
calculating the amount of change in the capacitance of the first capacitor;
calculating the amount of change in the capacitance of the second capacitor;
A deformation detection method for detecting deformation based on respective amounts of change in capacitance of the first capacitor and the second capacitor.

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