JP4023619B2 - Tactile sensor and method for manufacturing tactile sensor - Google Patents

Description

The present invention relates to a tactile sensor that has a simple configuration and can improve sensitivity, and a method for manufacturing the tactile sensor .

  Conventionally, this type of tactile sensor includes a plurality of LC series resonance circuits configured by connecting a coil and a capacitor in series. An external oscillator and a spectrum analyzer are attached to the LC series resonance circuit, and an input signal such as a swept electrical signal is input to the LC series resonance circuit by the external oscillator and then output to the spectrum analyzer. The LC series resonance circuit has a resonance frequency based on the intrinsic frequency of the coil, and the signal strength of the signal output to the spectrum analyzer decreases at a frequency corresponding to the resonance frequency of the LC series resonance circuit (see, for example, Patent Document 1). .)

When a tactile pressure is applied to the tactile sensor, the coil pitch (winding interval) and area change due to the tactile pressure, and the coil inductance changes with this change. Here, the resonance frequency of the LC series resonance circuit varies as the inductance of the coil changes. Therefore, in the signal output to the spectrum analyzer, the position where the signal intensity decreases is displaced with the fluctuation of the resonance frequency of the LC series resonance circuit, so that the fluctuation of the resonance frequency of the LC series resonance circuit can be detected. For this reason, the tactile pressure can be detected by the tactile sensor.
JP 2002-236059 A (pages 2 to 5)

  However, this conventional tactile sensor has a problem that its configuration is complicated because an LC series resonance circuit is configured by connecting a coil and a capacitor in series. Further, the resonance frequency of the LC series resonance circuit fluctuates only by a change in the inductance of the coil. For this reason, for example, when a weak tactile pressure is applied to the tactile sensor and the inductance of the coil hardly changes, the resonance frequency of the LC series resonance circuit hardly changes. Therefore, the tactile sensor cannot detect a weak tactile pressure in which the inductance of the coil hardly changes, and there is a problem that the sensitivity is low.

The present invention has been made paying attention to the problems existing in the prior art as described above. An object of the present invention is to provide a tactile sensor having a simple configuration and improving sensitivity, and a method for manufacturing the tactile sensor .

In order to achieve the above object, a tactile sensor according to claim 1 includes a medium formed of a dielectric material, having a capacitance (C) component, and deformed when a contact pressure is applied, and a coiled carbon fiber. A plurality of sensors which are provided in the medium and have an inductance (L) component, a capacitance (C) component and a resistance (R) component based on the helical structure of the coiled carbon fiber, and act as an LCR resonance circuit An element and a pair of electrodes electrically connected to the medium, and the coiled carbon fiber has a coil diameter of 1 nm to 50 μm and a coil length of 10 nm to 10 mm. The content exceeds 1.0% by mass with respect to the medium and is set to 10.0% by mass or less .

A tactile sensor according to a second aspect of the present invention is the touch sensor according to the first aspect, wherein the coiled carbon fiber has a crystallized graphite layer .
A tactile sensor according to a third aspect of the present invention is the touch sensor according to the first or second aspect, wherein a coating layer made of a conductive material is formed on an outer peripheral surface of the coiled carbon fiber, and the coating A layer is formed in the ratio of 1-50 mass% with respect to coiled carbon fiber .

A tactile sensor according to a fourth aspect of the present invention is the tactile sensor according to any one of the first to third aspects, wherein the sensor element is composed of coiled carbon fibers having different coil diameters. Is.
A tactile sensor according to a fifth aspect of the present invention is the touch sensor according to any one of the first to fourth aspects, wherein each sensor element is provided in the medium in an oriented state. is there.
A tactile sensor according to a sixth aspect of the present invention is the tactile sensor according to any one of the first to fifth aspects, wherein the piezoelectric powder is dispersed in the medium.
According to a seventh aspect of the present invention, there is provided a method of manufacturing a tactile sensor, comprising: an inductance (L) component and a capacitance (C) component based on a helical structure of a coiled carbon fiber formed of a coiled carbon fiber in a liquid silicone resin. A predetermined amount of a plurality of sensor elements having a resistance (R) component and acting as an LCR resonance circuit are blended, and a mixed liquid that is further stirred with a curing agent is prepared and filled into a mold. By solidifying, a medium that has a capacitance (C) component and is deformed when a contact pressure is applied is formed by a dielectric, and the medium is taken out of the mold and a pair of electrodes are electrically connected to the medium. In the tactile sensor manufacturing method, the coiled carbon fiber has a coil diameter of 1 nm to 50 μm and a coil length of 10 nm to 10 mm. , The content of the sensor element is set to 10.0 mass% with greater than 1.0% by weight relative to the medium.
According to an eighth aspect of the present invention, there is provided the tactile sensor manufacturing method according to the seventh aspect of the present invention, wherein the coiled carbon fiber is crystallized by subjecting amorphous carbon fiber to heat treatment at 1500 to 3000 ° C. Having a graphitized graphite layer.
According to a ninth aspect of the present invention, there is provided a method for manufacturing a tactile sensor according to the seventh or eighth aspect of the present invention, wherein the coiled carbon fiber has an outer peripheral surface on which an evaporation method, a thermal spraying method, a coating method, and a dipping method are applied. A coating layer made of a conductive material is formed by one method selected from mechanochemical methods, and the coating layer is formed at a ratio of 1 to 50% by mass with respect to the coiled carbon fiber.
According to a tenth aspect of the present invention, there is provided a method of manufacturing a tactile sensor according to any one of the seventh to ninth aspects, wherein the sensor element is applied by applying a magnetic field in which magnetic lines of force extend in one direction. Are provided in the medium in an oriented state.

The present invention has the following effects.
According to inventions of claim 1 to 10, it is possible to improve the sensitivity as well as the structure is simple. Moreover, the sensitivity can be easily adjusted.

According to the second and eighth aspects of the present invention, the coiled carbon fiber has a variation in electrical resistance that occurs when the carbon particles forming the carbon fiber are regularly arranged in the graphite layer and exposed to a varying magnetic field or the like. Therefore, the resonance characteristics become remarkable.

According to invention of Claim 3, 9, the electroconductivity of coiled carbon fiber can fully be improved.
According to the invention described in claim 6, by dispersing the piezoelectric powder in the medium, it is possible to stabilize the output of the sensor element acting as the LCR resonance circuit.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1A and 1B, the tactile sensor 11 of the first embodiment includes a plurality of sensor elements 13 randomly dispersed in a disk-shaped solid medium 12, and a metal such as copper. A pair of electrodes 14 formed of a material in a disk shape are attached to the upper surface and the lower surface of the medium 12 to form a disk shape. In FIGS. 1B, 2A and 2B, FIG. 4 and FIGS. 6A and 6B, it is easy to understand the sensor elements 13 distributed in the medium 12. For this reason, the medium 12 is drawn thick with its thickness exaggerated.

  Each electrode 14 is electrically connected to the medium 12 and one end of a conducting wire 15 is connected to each other. A power source 17 and a measuring instrument 18 such as an oscilloscope are attached to the other end of each conducting wire 15 via an amplifier circuit 16. Yes. Here, the electrode 14 being electrically connected to the medium 12 means that the electrode 14 is connected to the medium 12 so that a current is passed through the medium 12 via the electrode 14. The tactile sensor 11, the amplifier circuit 16, the power source 17 and the measuring device 18 constitute a tactile sensor system 19, and a current is supplied from the power source 17 to the medium 12 via the amplifier circuit 16, the conductive wire 15 and the electrode 14, and the voltage at the medium 12 is set. Such fluctuations are amplified by the amplifier circuit 16 and detected by the measuring instrument 18.

  The medium 12 mechanically connects the sensor elements 13 distributed to each other, and electrically connects the sensor elements 13 to each other, the electrodes 14, and the sensor elements 13. The medium 12 has lower conductivity than the coiled carbon fiber constituting the sensor element 13, and specific examples of the material include synthetic resin materials such as silicone resin, non-conductive magnetic materials such as ferrite, silica (silicon dioxide), and the like. Examples include ceramic materials and natural rubber. These may form the medium 12 alone, or two or more may be combined to form the medium 12.

  Here, the medium 12 existing between the sensor elements 13 dispersed in the medium 12 has a mass and acts as a mass point in the spring mass point system. For this reason, the sensor elements 13 are mechanically connected to each other, as shown in FIG. 2A, the sensor elements 13 dispersed in the medium 12 and acting as the microsprings 20 are connected to each other. And connecting via a medium 12 that acts as a mass point 21. On the other hand, when the sensor elements 13 are electrically connected to each other and the electrodes 14 and the sensor elements 13 are electrically connected to each other through the medium 12 existing between the sensor elements 13. In other words, the sensor elements 13, the electrodes 14, and the sensor elements 13 are connected to each other so as to flow through the sensor elements 13. Here, FIG. 2A shows an equivalent circuit in FIG.

  The medium 12 is preferably formed of a dielectric and has a capacitance (C) component. Specific examples of the medium 12 formed of a dielectric and having a C component include silicone resin. In this case, the medium 12 existing between the sensor elements 13 acts as an LCR resonance circuit by acting as a capacitor together with the coiled carbon fiber constituting the sensor element 13 and having a function as a C component. The capacitance of the capacitor in the sensor element 13 can be increased. For this reason, the adjustment range of the capacitance of the LCR resonance circuit can be increased. Here, the C component is a capacitance and shows a dielectric characteristic with respect to an electric field.

  The sensor element 13 is made of a coiled carbon fiber. Coiled carbon fiber is formed of a carbon material in a coil shape, and a single helical structure in which a single carbon fiber forms a helical structure, or a multiple helical structure in which two or more carbon fibers each form a helical structure in the same winding direction. It has one of the following helical structures. In addition, the winding direction of the carbon fiber includes a clockwise direction (right-handed) and a counterclockwise direction (left-handed) around the axis of the coil. Each has a left-handed form.

  This coiled carbon fiber has electrical conductivity, thermal conductivity, adsorptivity, surface activity, and biological activity, and acts as a microspring by expanding and contracting itself. Furthermore, the coiled carbon fiber has a resonance characteristic in which an induced electromotive force is generated according to Faraday's law when exposed to a varying magnetic field or the like. Here, the coiled carbon fiber has a unique frequency, and when the coiled carbon fiber receives an electromagnetic wave having the same frequency as this frequency, the amplitude is amplified by tuning these frequencies, A higher induced electromotive force is generated than when an electromagnetic wave having a frequency different from the intrinsic frequency is received.

  As shown in FIGS. 3A and 3B, the coiled carbon fiber 13a has an inductance (L) component 22, a C component 23, and a resistance (R) component 24 based on its helical structure, and an LCR resonance circuit 25. Acts as For this reason, when the coil length or the like varies due to the expansion and contraction of the coiled carbon fiber 13a, the sizes of the L component 22, the C component 23, and the R component 24 of the coiled carbon fiber 13a due to the variation of the coil length or the like. Vary. Therefore, the coiled carbon fiber 13a is electromagnetically converted by converting fluctuations in the coil length and the like due to the expansion and contraction into comprehensive fluctuations of the L component 22, the C component 23, and the R component 24 of the LCR resonance circuit 25. Can be converted to fluctuations. Here, the L component 22 is a self-induction coefficient or a mutual induction coefficient, and indicates electromagnetic induction characteristics. On the other hand, the R component 24 is an electrical resistance and exhibits dielectric characteristics.

  The coiled carbon fiber 13a may be composed of amorphous carbon fiber, but preferably has a graphite layer crystallized by subjecting the amorphous carbon fiber to heat treatment. In this case, the coiled carbon fiber 13a has a remarkable variation in electrical resistance that occurs when it is exposed to a varying magnetic field or the like by regularly arranging the carbon grains forming the carbon fiber in the graphite layer. Resonance characteristics become remarkable. Further, the fluctuation of the R component 24 and the like in the LCR resonance circuit 25 becomes remarkable. For this reason, the sensitivity of the tactile sensor 11 can be improved by improving the detection accuracy of the sensor element 13. Here, the heat treatment temperature is preferably 1500 to 3000 ° C. When the heat treatment temperature is less than 1500 ° C., the crystallization of the carbon fiber becomes insufficient, and even when it exceeds 3000 ° C., it cannot be further crystallized.

  The coiled carbon fiber 13a preferably has a coating layer made of a conductive material on the outer peripheral surface thereof. In this case, the conductivity of the coiled carbon fiber 13a can be improved. Specific examples of the conductive substance include metals such as gold, silver, copper, nickel, cobalt, and manganese, or compounds and alloys thereof. These may form a coating layer alone, or two or more types may be combined to form a coating layer. Specific examples of the compound include a cobalt-ferrite compound, and examples of the alloy include a cobalt-boron alloy.

  The coating layer is preferably formed at a ratio of 1 to 50% by mass with respect to the coiled carbon fiber 13a. Furthermore, the thickness of the coating layer is preferably 0.1 nm to 5 μm, more preferably 0.1 to 200 nm. When the ratio or thickness of the coating layer to the coiled carbon fiber 13a is less than the above range, the conductivity of the coiled carbon fiber 13a cannot be sufficiently improved. On the other hand, if the above range is exceeded, it takes time to form the coating layer, and the manufacturing efficiency of the sensor element 13 may be reduced.

  The coating layer is an electroless plating method, an electrolytic plating method, a physical vapor deposition method such as a vacuum vapor deposition method or a sputtering method, a chemical vapor deposition method, a thermal spraying method, a coating method, a dipping method, or a mechanochemical that mechanically fixes fine particles. It is formed by one method selected from the methods. Among these methods, the electroless plating method is preferable because the coating layer can be uniformly formed on the outer peripheral surface of the coiled carbon fiber 13a.

  The coil diameter of the coiled carbon fiber 13a is preferably 1 nm to 50 μm, and the coil length is preferably 10 nm to 10 mm. If the coil diameter is less than 1 nm, it is difficult to manufacture the coiled carbon fiber 13a. In addition, when the coil length is less than 10 nm, the coiled carbon fiber 13a cannot sufficiently function as the L component 22 because the coil length is short. On the other hand, when the coil diameter exceeds 50 μm or the coil length exceeds 10 mm, the sensor element 13 formed by the coiled carbon fiber 13a becomes large, and it is difficult to reduce the size of the tactile sensor 11. Furthermore, the fiber diameter of the carbon fiber is preferably 1 nm to 10 μm. If the fiber diameter is less than 1 nm, it is difficult to produce the coiled carbon fiber 13a. On the other hand, when the fiber diameter exceeds 10 μm, it is difficult to make the coil diameter within the above range. Here, the concept of the fiber diameter is not limited to the diameter of the fiber formed in a circular cross section, but the length of the long side (long diameter) of the fiber formed in an elliptical cross section, or the fiber formed in a square cross section Including long side length. Each sensor element 13 dispersed in the medium 12 may be composed of coiled carbon fibers 13a having different coil diameters or the like, or may be composed of coiled carbon fibers 13a having the same coil diameter. Good.

  The coiled carbon fiber 13a may be manufactured by any manufacturing method, but the coiled carbon fiber is manufactured by a vapor phase growth method such as a catalyst activated CVD (chemical vapor deposition) method. It is preferable because the coil diameter and coil length of 13a can be easily within the above ranges. In this vapor phase growth method, a hydrocarbon such as acetylene or carbon monoxide as a carbon material is heated to 600 to 3000 ° C. in the presence of a metal catalyst, and the hydrocarbon or carbon monoxide is decomposed in the gas phase. is there. Most of the coiled carbon fibers 13a obtained by this vapor phase growth method are formed in a state in which fine carbon particles are packed up to the central portion of the carbon fibers, and some of them are formed in a hollow shape. Observed.

  The content of the sensor element 13 in the touch sensor 11 is preferably set to 10.0% by mass or less and more than 1.0% by mass with respect to the medium 12. When the content of the sensor element 13 is 1.0% by mass or less, since the content of the sensor element 13 is low, the tactile sensor 11 cannot sufficiently detect the tactile pressure and the sensitivity may be lowered. On the other hand, when it exceeds 10.0 mass%, most of the sensor elements 13 dispersed in the medium 12 are in direct contact with each other without the medium 12 being interposed.

  Here, the coiled carbon fiber 13a constituting the sensor element 13 is dispersed in, for example, a curved state in the medium 12, thereby functioning as the C component 23 via the medium 12 existing between both ends thereof. To demonstrate. For this reason, since the medium 12 does not exist between the both ends of the coiled carbon fiber 13a due to the direct contact between the coiled carbon fibers 13a, the sensor element 13 exhibits the function as the C component 23. It becomes difficult.

  As shown in FIG. 2A, the sensor elements 13 dispersed in the medium 12 are connected to each other via the mass points 21 with the medium 12 existing between the sensor elements 13 as the mass points 21. A mechanical mechanical equivalent circuit 26 of a composite spring mass point system is configured. Further, as shown in FIG. 2B, when the medium 12 is formed of a dielectric and has a C component, the medium 12 existing between the sensor elements 13 acts as a capacitor.

  The sensor elements 13 dispersed in the medium 12 are connected to each other via the medium 12 existing between the sensor elements 13, thereby forming an electrical equivalent circuit 27 that is a composite resonance circuit. ing. For this reason, as shown in FIG. 4, the sensor elements 13 dispersed in the medium 12 can function as one LCR resonance circuit 25 by collecting all the sensor elements in an electrical equivalent circuit. Here, FIG. 2B shows an equivalent circuit in FIG.

  The power source 17 always applies a constant current, for example, to the medium 12 through the amplifier circuit 16, the conductive wire 15, and the electrode 14. The current supplied from the power source 17 to the medium 12 may be direct current or alternating current. In the case of alternating current, the frequency is, for example, 10 kHz to 1 MHz, and the waveform is not particularly limited, and may be a sine wave or a rectangular wave.

  The amplification circuit 16 amplifies the fluctuation of the voltage in the medium 12 to an intensity that can be detected by the measuring instrument 18. It is preferable that the amplifier circuit 16 can detect a minute voltage fluctuation such as 1 μV, can reduce the influence of electric noise received from the outside, and has low electric noise generated by the amplifier circuit 16 itself. In this case, it is possible to detect and amplify a minute voltage fluctuation or the like due to a weak contact pressure without being affected by an external electric noise or the like.

  Now, when manufacturing the tactile sensor 11 in which the medium 12 is formed of a silicone resin comprising a silicone monomer such as methylchlorosilanes and a liquid main agent and a curing agent containing a silicone monomer polymerization catalyst, A predetermined amount of the sensor element 13 is blended in the main component of the silicone resin. Next, after blending the curing agent and preparing a mixed solution, the mixed solution is filled in the cavity inside the mold before the mixed solution is solidified by polymerization of the silicone monomer, and the mixed solution is formed in the mold. The medium 12 is formed by solidifying. Here, the cavity inside the mold is formed to correspond to the shape of the disk-shaped medium 12.

  Subsequently, after releasing the mold, the medium 12 is taken out of the mold, and the electrodes 14 are attached to the upper and lower surfaces of the medium 12 with an adhesive or the like to manufacture the tactile sensor 11. Then, after one end of the conducting wire 15 is attached to the electrode 14 by welding or the like, a power source 17 and a measuring instrument 18 are attached to the other end of each conducting wire 15 via the amplifier circuit 16 to constitute a tactile sensor system 19.

  When this tactile sensor 11 is used, for example, an alternating current is first supplied to the medium 12 by the power source 17. Here, the sensor elements 13 dispersed in the medium 12 are configured as shown in the equivalent circuits of FIGS. 2 (a) and 2 (b). When a contact pressure is applied to a part or the whole of the tactile sensor 11, the length of the micro spring 20 at the location where the contact pressure is applied varies due to the contact pressure in the mechanical mechanical equivalent circuit 26 of the composite spring mass system. To do. Alternatively, the mass point 21 at the location where the contact pressure is applied fluctuates due to a decrease in the volume of the medium 12 existing between the sensor elements 13 due to the contact pressure.

  At this time, since the sensor element 13 also functions as the LCR resonance circuit 25, the fluctuation of the length of the small spring and the mass point 21 is converted into a total fluctuation of the L component 22, the C component 23, and the R component 24, thereby electromagnetically. Can be converted into dynamic fluctuations. For this reason, the voltage of the LCR resonance circuit 25 fluctuates, and the fluctuation of the voltage or the like can be detected by the measuring device 18 after being amplified by the amplifier circuit 16. Therefore, the tactile pressure can be detected by the tactile sensor 11.

According to the first embodiment described in detail above, the following effects are exhibited.
-The sensor element 13 which comprises the tactile sensor 11 of 1st Embodiment is comprised by the coil-shaped carbon fiber 13a. For this reason, the structure of the tactile sensor 11 can be simplified by simplifying the structure of the sensor element 13 as compared with the conventional tactile sensor. Further, the sensor elements 13 dispersed in the medium 12 are configured as a composite spring mass point system mechanical mechanical equivalent circuit 26, and when a touch pressure is applied to the tactile sensor 11, the composite spring mass point system is caused by the contact pressure. In the mechanical mechanical equivalent circuit 26 of FIG.

  At this time, since the sensor element 13 functions as the LCR resonance circuit 25 and is configured as the electrical equivalent circuit 27, the fluctuation of the length of the microspring 20 is changed to the total of the L component 22, the C component 23, and the R component 24. Can be converted to electromagnetic fluctuations. For this reason, the sensitivity of the tactile sensor 11 can be improved as compared with the conventional tactile sensor that detects the tactile pressure only by changing the inductance of the coil.

  In addition, by changing the coil length or the like of the coiled carbon fiber 13a constituting the sensor element 13, the length or the like of the microspring 20 in the mechanical mechanical equivalent circuit 26 can be easily changed, and the LCR The size of the L component 22 and the like in the resonance circuit 25 can be easily changed. Therefore, since the sensitivity of the sensor element 13 can be easily adjusted only by changing the coil length or the like of the coiled carbon fiber 13a, the sensitivity of the touch sensor 11 can be easily adjusted.

  The medium 12 is preferably formed of a dielectric and has a C component 23. In this case, the medium 12 existing between the sensor elements 13 acts as a capacitor together with the coiled carbon fiber 13 a constituting the sensor element 13, thereby adjusting the capacitance of the LCR resonance circuit 25. Can be increased. For this reason, the sensitivity of the touch sensor 11 can be adjusted more easily.

  The content of the sensor element 13 in the tactile sensor 11 is preferably set to 10.0% by mass or less and more than 1.0% by mass with respect to the medium 12. In this case, the sensitivity of the touch sensor 11 can be further improved.

  The coiled carbon fiber 13a preferably has a graphite layer. In this case, the resonance characteristics of the coiled carbon fiber 13a and the fluctuation of each component in the LCR resonance circuit 25 can be made remarkable, so that the sensitivity of the touch sensor 11 can be further improved.

  The coil diameter of the coiled carbon fiber 13a constituting the sensor element 13 is preferably 1 nm to 50 μm, and the coil length is preferably 10 nm to 10 mm. In this case, since the sensor element 13 is small, the tactile sensor 11 can be downsized.

(Second Embodiment)
Hereinafter, the second embodiment of the present invention will be described in detail. Note that the second embodiment will be described with a focus on differences from the first embodiment.

  The tactile sensor 11 according to the second embodiment is configured such that a plurality of sensor elements 13 are randomly distributed in a medium 12 and the electrodes 14 are attached to the upper surface and the lower surface of the medium 12, respectively. The medium 12 electrically connects the sensor elements 13 to each other and the electrodes 14 and the sensor elements 13. The medium 12 has lower conductivity than the conductive fibers constituting the sensor element 13, and the specific example is the same as in the first embodiment. The medium 12 is preferably formed of the dielectric and has a C component. In this case, the medium 12 existing between the sensor elements 13 can increase the capacitance of the capacitor in the sensor element 13 acting as the LCR resonance circuit 25. As a result, the adjustment range of the capacitance of the LCR resonance circuit 25 can be increased.

  The sensor element 13 is made of a conductive fiber. This conductive fiber is formed of a conductive material. Specific examples of the conductive material include metal materials such as copper and silver, alloy materials such as titanium carbide (TiC), titanium nitride (TiN), and zinc oxide (ZnO), carbon Examples thereof include polymer materials such as materials and polyacetylene. Examples of the fiber shape of the conductive fiber include a linear shape and a cylindrical shape. The manufacturing method of this conductive fiber is not specifically limited, The said vapor phase growth method etc. are mentioned. Specific examples of the conductive fibers include carbon nanotubes, VGCF (vapor-grown carbon fibers), carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers, and conductive whiskers. These may constitute the sensor element 13 alone, or two or more types may be combined to constitute the sensor element 13.

  The conductive fiber has an L component 22, a C component 23, and an R component 24, and acts as an LCR resonance circuit 25, and has elasticity. That is, the conductive fiber bends easily, for example, when stress is applied from the outside, and this bending causes distortion inside to change the R component 24, and also the positional relationship with the medium 12 compared to before bending. The reactance components (L component 22 and C component 23) change due to the difference.

  The conductive fiber preferably has a fiber diameter of 1 nm to 10 μm, a fiber diameter of preferably 1 nm to 50 μm, and a fiber length of preferably 10 nm to 10 mm. Here, the fiber diameter indicates the diameter when the shape of the conductive fiber is linear, and indicates the thickness of the peripheral wall when the shape is cylindrical. Further, the fiber diameter indicates the diameter when the fiber shape is linear, and indicates the diameter of the outer periphery in the cross section when the fiber shape is cylindrical. In addition, the concept of the diameter of the fiber is not limited to the diameter of the fiber formed in a circular cross section, the length of the long side (long diameter) of the fiber formed in an elliptical cross section, or the fiber formed in a square cross section Including the length of the long side.

  If the fiber diameter or the fiber diameter is less than 1 nm, the change in the R component 24 when the conductive fiber is bent may be small. Moreover, if the fiber length is less than 10 nm, the conductive fiber cannot be bent sufficiently. On the other hand, when the fiber diameter exceeds 10 μm, the fiber diameter exceeds 50 μm, or the fiber length exceeds 10 mm, it takes time to manufacture the conductive fiber, which may reduce the manufacturing efficiency. Furthermore, since the sensor element 13 made of conductive fibers is large, it is difficult to reduce the size of the touch sensor 11.

  The conductive fiber preferably has an aspect ratio obtained by dividing the fiber length by the fiber diameter from 2 to 10,000, more preferably from 100 to 1,000, and most preferably from 200 to 800. If the aspect ratio is less than 2, the conductive fibers cannot be bent sufficiently. Conversely, if the aspect ratio exceeds 10,000, the conductive fibers become excessively long and the production efficiency is lowered, and the tactile sensor 11 is difficult to downsize. Become.

  The conductive fiber preferably has the coating layer formed on the outer peripheral surface thereof. In this case, the conductivity of the conductive fiber can be improved. Specific examples of the conductive material forming the coating layer, the ratio and thickness of the coating layer to the conductive fibers, and the method for forming the coating layer are the same as those in the first embodiment.

  When using the tactile sensor 11, for example, an alternating current is first supplied to the medium 12 by the power source 17. Here, the sensor elements 13 dispersed in the medium 12 are configured as an electrical equivalent circuit. When tactile pressure is applied to a part or the whole of the tactile sensor 11, the sensor element 13 is bent, and this bending changes the R component 24 and the reactance component. For this reason, the contact pressure can be converted into an electromagnetic fluctuation by changing into a total fluctuation of the L component 22, the C component 23, and the R component 24.

According to the second embodiment described in detail above, the following effects are exhibited.
-The sensor element 13 which comprises the tactile sensor 11 of 2nd Embodiment is comprised with the electroconductive fiber. For this reason, the tactile sensor 11 can be simplified in configuration as compared with the conventional tactile sensor, similarly to the first embodiment. Furthermore, since the sensor element 13 functions as an LCR resonance circuit 25 and is configured as an electrical equivalent circuit, the contact pressure can be converted into electromagnetic fluctuations. For this reason, the tactile sensor 11 of the second embodiment can improve the sensitivity as compared with the conventional tactile sensor. In addition, the size of the L component 22 and the like in the LCR resonance circuit 25 can be easily changed by changing the fiber length and the like of the conductive fibers constituting the sensor element 13. For this reason, since the sensitivity of the sensor element 13 can be easily adjusted only by changing the fiber length or the like of the conductive fiber, the sensitivity of the tactile sensor 11 can be easily adjusted.

In addition, the said embodiment can also be changed and comprised as follows.
In each of the above embodiments, the shape of the medium 12 may be changed to a polygonal plate shape such as a square plate shape. Further, as shown in FIG. 5 (a), the tactile sensor 11 has a rectangular plate shape and a pair of electrodes 14 having an elongated square plate shape on both sides of the lower surface of the medium 12 in which the sensor elements are dispersed. You may form by attaching. Further, as shown in FIG. 5B, a medium 12 having a quadrangular prism shape and sensor elements dispersed therein is attached to the upper surface of a pedestal 28 formed of an acrylic resin in a substantially quadrangular prism shape. Next, the tactile sensor 11 may be formed by attaching a pair of electrodes 14 formed in the shape of a plow on both sides of the lower portion of the medium 12 and the upper portion of the base 28.

  In each of the embodiments, the sensor elements 13 are dispersed in the liquid medium 12 and then a magnetic field extending in one direction is applied to the sensor elements 13 so that all the sensor elements 13 are aligned in parallel with the magnetic lines. . Then, by solidifying the medium 12, as shown in FIG. 6A, the sensor elements 13 may be dispersed in the medium 12 in a state of being oriented in the same direction. In addition, after filling the mold 12 with the liquid medium 12 to about one third of the volume of the mold, the sensor elements 13 are dispersed in the medium 12, and the sensor elements 13 are oriented in the same direction as described above. In this state, the medium 12 is solidified. Next, by repeating the same operation as described above, as shown in FIG. 6B, the sensor elements 13 may be dispersed in the medium 12 so as to form a lattice shape.

In each of the above embodiments, only one sensor element 13 may be provided in the medium 12.
In each of the above embodiments, the piezoelectric powder may be dispersed in the medium 12. Specific examples of the piezoelectric powder include ferrite, titanium oxide (TiO ₂ ), lead zirconate (PbZrO ₃ ), lead titanate (PbTiO ₃ ), lead zirconate titanate (PbZrTiO ₃ ), and barium titanate (BaTiO ₃ ). Etc. At this time, the output of the sensor element 13 acting as the LCR resonance circuit 25 can be stabilized by dispersing the piezoelectric powder in the medium 12.

  -In the said 1st Embodiment, even if the sensor element 13 comprised by the electroconductive fiber of 2nd Embodiment is disperse | distributed in the said medium 12 with the sensor element 13 comprised by the coil-shaped carbon fiber 13a. Good. In the second embodiment, the sensor element 13 constituted by the coiled carbon fiber 13a of the first embodiment may be dispersed in the medium 12 together with the sensor element 13 constituted by the conductive fiber. .

Next, the embodiment will be described more specifically with reference to examples and comparative examples.
(Examples 1 to 3 and Comparative Example 1)
In Example 1, first, the sensor element 13 made of the coiled carbon fiber 13a was blended with the main ingredient of the two-pack type silicone resin (Shin-Etsu Silicone KE103; manufactured by Shin-Etsu Chemical Co., Ltd.) made of the main agent and the curing agent, and then further. A liquid mixture was prepared by blending a curing agent. Here, the mixing ratio of the main agent and the curing agent was set to main agent: curing agent = 100: 5 in mass ratio. Next, the mixed solution is stirred for 5 minutes to randomly disperse the sensor elements 13 in the mixed solution, and then, before the mixed solution is cured, the mixed solution is filled into the cavity inside the mold, and the mixed solution is cured. Medium 12 was formed. Here, the medium 12 has a disk shape with a diameter of 10 cm and a thickness of 20 mm, and the cavity inside the mold is formed to correspond to the shape of the medium 12 having a disk shape.

  Subsequently, after releasing the mold, the medium 12 is taken out of the mold, and the electrodes 14 having a disk shape with a diameter of 10 cm and a thickness of 5 mm are respectively attached to the upper surface and the lower surface of the medium 12 to attach the tactile sensor 11. Obtained. Then, after attaching one end of the conducting wire 15 to each electrode 14, a power source 17 and an oscilloscope as a measuring instrument 18 were attached to the other end of each conducting wire 15 via the amplifier circuit 16 to configure the tactile sensor system 19.

  Here, the coiled carbon fiber 13a constituting each sensor element 13 had a coil diameter in the range of 5 to 10 μm and a coil length of 90 to 150 μm. Further, the content of the sensor element 13 was 1.0 mass% with respect to the medium 12. In Example 2, the content of the sensor element 13 is changed to 2.0% by mass with respect to the medium 12, and in Example 3, the content of the sensor element 13 is set to 3.0% by mass with respect to the medium 12. Except for this, the tactile sensor 11 was obtained in the same manner as in Example 1. On the other hand, in Comparative Example 1, a tactile sensor 11 was obtained in the same manner as in Example 1 except that the medium 12 was formed without blending the sensor element 13. And about the tactile sensor 11 of each example, evaluation was performed regarding the item of following (1)-(5).

(1) Constant load test After placing the beaker on the tactile sensor 11 of each example, water was supplied into the beaker, and the change in the waveform on the oscilloscope was measured. The amount of water supply increased from 100 ml to 100 ml, and the upper limit was 1000 ml. In addition, a weight was placed on the tactile sensor 11, and changes in the waveform on the oscilloscope were observed. Here, the weight of the weight was increased from 0.3 g by 0.3 g, and the upper limit was 3.0 g.

  As a result, in Examples 1 to 3, an impulse response waveform was shown according to the water supply or the placement of the weight. In Example 3, a remarkable response waveform was shown, and in Example 2, a response waveform smaller than that in Example 3 was shown. In Example 1, the response waveform was smaller and weaker than that in Example 2. For this reason, the tactile sensor 11 of Examples 1 to 3 can detect a contact pressure due to a load such as water supply. In Example 2 and Example 3, the content of the sensor element 13 is 1.0% by mass. Therefore, the sensitivity of the tactile sensor 11 could be improved as the content of the sensor element 13 increased. Furthermore, the magnitude of the response waveform was dependent on the amount of water supply and the impact level at the time of water supply. On the other hand, in Comparative Example 1, the response waveform was not shown and the contact pressure due to the load could not be detected.

(2) Displacement Test As shown in FIG. 7, the tactile sensor 11 of each example was attached to the piezoelectric preload application device 29. Here, the piezoelectric preload application device 29 is configured such that the L-plate-shaped preload 30 moves in the vertical direction in FIG. 7 and the movement distance of the preload 30 is adjusted by the controller 31. The lower surface of the preload 30 is in contact with the upper surface of the tactile sensor 11 and the position of the lower surface of the preload 30 when the tactile sensor 11 is not pressed by the preload 30 is used as a reference surface. 30 was moved or displaced. And the change of the waveform with an oscilloscope when the preload 30 displaced was measured. Here, the moving distance of the preload 30 was increased by 50 μm or 100 μm, and the upper limit was set to 3000 μm. Further, the length was increased by 20 μm and the upper limit was set to 200 μm.

  As a result, in Examples 1 to 3, an impulse response waveform was shown according to the displacement of the preload 30. Here, the response waveforms in the first to third embodiments show the same tendency as (1) the constant load test, and the tactile sensor 11 of the first to third embodiments can detect the tactile pressure due to the displacement of the preload 30 and implement it. In Example 2 and Example 3, the sensitivity of the tactile sensor 11 could be improved. On the other hand, in Comparative Example 1, no response waveform was shown and the contact pressure due to the displacement of the preload 30 could not be detected.

(3) Impact test A weight having a predetermined mass was dropped on the tactile sensor 11 from a predetermined height and collided, and a change in waveform on the oscilloscope was measured. Here, the mass of the weight was 1 g, 3 g, 5 g, or 10 g, and the weight was dropped from the vertical direction with respect to the tactile sensor 11, and the height was increased from 10 cm by 5 cm, and the upper limit was 40 cm. Here, the height at which the weight is dropped indicates the distance between the upper surface of the touch sensor 11 and the weight before being dropped.

  As a result, in Examples 1 to 3, an impulse response waveform was shown according to the impact caused by the collision of the weight. Here, the response waveforms in the examples 1 to 3 show the same tendency as (1) the constant load test, and the tactile sensor 11 of the examples 1 to 3 can detect the contact pressure due to the impact, and the examples 2 and In Example 3, the sensitivity of the tactile sensor 11 could be improved. On the other hand, in Comparative Example 1, no response waveform was shown and the contact pressure due to impact could not be detected.

(4) Minimum Sensitivity Test The tactile sensor 11 of the third embodiment was attached to the piezoelectric preload application device 29 in the same manner as the (2) displacement test. And the change of the waveform in an oscilloscope when the preload 30 was moved below from the reference plane was measured. Here, the movement distance of the preload was 10 μm, 5 μm, 1 μm, 0.5 μm, or 0.1 μm. As a result, an impulse-like response waveform was shown according to the displacement of the preload 30 at any moving distance of the preload 30. For this reason, the tactile sensor 11 of Example 3 was able to detect a tactile pressure due to a minute displacement of the preload 30 such as 0.1 μm.

(5) Stimulus type test Stimulus was directly applied to the tactile sensor 11 of each example with a human finger, toothpick, a round bar having a diameter of 5 cm, a twist, or the like, and a change in waveform on an oscilloscope was measured. Here, when a stimulus is applied to the tactile sensor 11 using a human finger, three types of pressing down the tactile sensor 11 and lightly touching or stroking the surface of the tactile sensor 11 were performed. When a toothpick is used, the surface of the tactile sensor 11 is pushed down by 1 mm with the toothpick, lightly touching the surface of the tactile sensor 11, stroked, continuously thrusting, thrusting lightly, or strongly pressing the surface of the tactile sensor 11 with the toothpick. Six types of separating the toothpick from the surface of the touch sensor 11 were performed. On the other hand, when the round bar was used, the tactile sensor 11 was pushed down, and when using this, the surface of the tactile sensor 11 was stroked.

  As a result, in Examples 1 to 3, impulse response waveforms were shown according to various stimuli. Here, in Example 3, the response waveform in the oscilloscope when the tactile sensor 11 is pushed down with the finger is shown in FIG. 8A, and the response waveform when the surface of the tactile sensor 11 is lightly touched with the finger is shown in FIG. FIG. 8C shows a response waveform when the surface of the touch sensor 11 is stroked with a finger. On the other hand, FIG. 8D shows a response waveform when the surface of the touch sensor 11 is pushed down by 1 mm with a toothpick, and FIG. 8E shows a response waveform when the surface of the touch sensor 11 is lightly touched with a toothpick. FIG. 8F shows a response waveform when the surface of the tactile sensor 11 is boiled with a toothpick, and FIG. 9A shows a response waveform when the surface of the tactile sensor 11 is continuously projected with a toothpick.

  Furthermore, the response waveform when the surface of the tactile sensor 11 is lightly struck with a toothpick is shown in FIG. 9B, and when the surface of the tactile sensor 11 is strongly pressed with the toothpick and then the toothpick is separated from the surface of the tactile sensor 11. The response waveform is shown in FIG. FIG. 9D shows a response waveform when the surface of the tactile sensor 11 is struck with a round bar, and FIG. 9E shows a response waveform when the surface of the tactile sensor 11 is stroked with this rod. In FIGS. 8A to 9E, the voltage displacement 32 in the R component and the voltage displacement 33 in the L component and the C component are shown separately.

The response waveforms in Examples 1 to 3 show the same tendency as (1) the constant load test, and the tactile sensor 11 in Examples 1 to 3 can detect tactile pressure due to various stimuli, and Examples 2 and Example. 3, the sensitivity of the touch sensor 11 could be improved. On the other hand, in Comparative Example 1, no response waveform was shown and the tactile pressure due to various stimuli could not be detected.
(Examples 4 to 9)
In Example 4, the shape of the medium 12 is changed to a rectangular plate shape with a length and width of 100 mm and a thickness of 5 mm as shown in FIG. A tactile sensor 11 was obtained in the same manner as in Example 1 except that the electrode 14 having a thickness of 0.1 mm was attached. In Example 5, the content of the sensor element 13 is changed to 2.0% by mass with respect to the medium 12, and in Example 6, the content of the sensor element 13 is changed to 3.0% by mass with respect to the medium 12. A tactile sensor 11 was obtained in the same manner as in Example 4 except that.

  In Example 7, the shape of the medium 12 is changed to a quadrangular prism shape having a length and width of 10 mm and a thickness of 5 mm as shown in FIG. 5B, and the medium 12 is formed on the upper surface of the pedestal 28 formed of acrylic resin. Install. Here, the upper portion of the pedestal 28 has a rectangular column shape with a vertical, horizontal, and thickness of 10 mm, and a lower portion has a cylindrical shape with a diameter of 10 mm and a thickness of 10 mm.

  Next, a tactile sensor 11 was obtained in the same manner as in Example 1 except that the pave-like electrodes 14 were attached to both sides of the lower part of the medium 12 and the upper part of the pedestal. In Example 8, the content of the sensor element 13 is changed to 2.0% by mass with respect to the medium 12, and in Example 9, the content of the sensor element 13 is changed to 3.0% by mass with respect to the medium 12. A tactile sensor 11 was obtained in the same manner as in Example 7 except that.

  And about the tactile sensor 11 of Examples 4-9, it evaluated regarding the item of said (5). As a result, in each Example, an impulse-like response waveform was shown according to various stimuli, and each response waveform showed the same tendency as (1) constant load test. For this reason, the tactile sensors 11 of the fourth to ninth embodiments can detect tactile pressure due to various stimuli and improve the sensitivity of the tactile sensor 11 in the fifth, sixth, eighth, and ninth embodiments. I was able to.

(Examples 10 to 20)
In Example 10, the medium 12 is formed in a disk shape having a diameter of 10 mm and a thickness of 3 mm. Then, a pair of electrodes 14 (thickness 0.5 mm, width 3 mm, length 30 mm, distance between the electrodes 2.5 mm) attached to the lower surface of the medium 12 was obtained. Further, a tactile sensor system was configured in the same manner as in Example 1 except that the sensor element 13 was composed of VGCF. Here, VGCF had a fiber diameter in the range of 50 to 100 nm and a fiber length in the range of 10 to 50 μm. Further, the content of the sensor element 13 was 1 mass% with respect to the medium 12.

  In Example 11, the content of the sensor element 13 was changed to 2% by mass with respect to the medium 12, and in Example 12, the content of the sensor element 13 was changed to 5% by mass with respect to the medium 12, A tactile sensor 11 was obtained in the same manner as in Example 10. In Example 13, the tactile sensor 11 was obtained in the same manner as in Example 12 except that the thickness of the medium 12 was changed to 0.5 mm.

  In Example 14, the tactile sensor 11 was obtained in the same manner as in Example 10 except that the sensor element 13 was composed of carbon nanotubes and the content of the sensor element 13 was set to 5% by mass with respect to the medium 12. . Here, the carbon nanotubes had a fiber diameter in the range of 0.7 to 50 nm and a fiber length in the range of 0.01 to 100 μm. In Example 15, the tactile sensor 11 was obtained in the same manner as in Example 12 except that ferrite was dispersed in the medium 12. Here, the ferrite content was 5 mass% with respect to the medium 12. In Example 16, the tactile sensor 11 was obtained in the same manner as in Example 14 except that ferrite was dispersed in the medium 12. Here, the ferrite content was 5 mass% with respect to the medium 12.

  In Example 17, the tactile sensor 11 was obtained in the same manner as in Example 15 except that the sensor element 13 was composed of the VGCF and the coiled carbon fiber. Here, the coiled carbon fiber had a coil diameter in the range of 5 to 10 μm and a coil length of 90 to 150 μm. Further, the content of the sensor element 13 made of VGCF and the sensor element 13 made of coiled carbon fiber was 5% by mass with respect to the medium 12.

  In Example 18, the tactile sensor 11 was obtained in the same manner as in Example 10 except that the sensor element 13 was composed of the coiled carbon fiber and the carbon nanotube. Here, the content of the sensor element 13 made of a coiled carbon fiber and the sensor element 13 made of a carbon nanotube was 5 mass% with respect to the medium 12. In Example 19, the tactile sensor 11 was obtained in the same manner as in Example 10 except that the sensor element 13 was composed of the VGCF and the coiled carbon fiber. Here, the content of the sensor element 13 made of VGCF and the sensor element 13 made of coiled carbon fiber was set to 5% by mass with respect to the medium 12.

  In Example 20, a tactile sensor 11 was obtained in the same manner as in Example 10 except that the sensor element 13 was composed of the coiled carbon fiber and the PAN-based carbon fiber. Here, the PAN-based carbon fiber had a fiber diameter of 1 to 30 μm and a fiber length of 0.01 to 10 mm. Furthermore, the content of the sensor element 13 made of coiled carbon fiber and the sensor element 13 made of PAN-based carbon fiber was 5% by mass with respect to the medium 12. And about the tactile sensor 11 of each example, evaluation was performed regarding the item of following (6).

(6) Pressing test After pressing the tactile sensor 11 of each example intermittently (at intervals of 0.3 to 0.5 seconds) using a quartz rod (diameter 0.5 cm, weight 1 g) attached to the manipulator. Further, the tactile sensor 11 was continuously pressed for 3 to 5 seconds, and the change in the waveform with an oscilloscope was measured. As a result, in Examples 10 to 20, an impulse-like response waveform was shown according to the pressure applied by the quartz rod, and the tactile pressure due to the pressure could be detected. Here, FIG. 10A shows the response waveform in Example 10, FIG. 10B shows the response waveform in Example 11, FIG. 10C shows the response waveform in Example 12, and FIG. 10 shows the response waveform in Example 13. 10 (d), the response waveform in Example 14 is shown in FIG. 10 (e), and the response waveform in Example 15 is shown in FIG. 10 (f). Further, FIG. 11A shows the response waveform in Example 16, FIG. 11B shows the response waveform in Example 17, FIG. 11C shows the response waveform in Example 18, and FIG. 11 shows the response waveform in Example 19. (D) The response waveform in Example 20 is shown in FIG.

(Example 21)
In Example 21, the tactile sensor 11 was obtained in the same manner as Example 12. And about the tactile sensor 11 of Example 21, it evaluated regarding the item of said (6). Here, the weight of the quartz rod was 20 g. As a result, in Example 21, as in Examples 10 to 20, an impulse-like response waveform was shown according to the pressing by the quartz rod, and the tactile pressure due to the pressing could be detected. Here, the response waveform in Example 20 is shown in FIG.

(Example 22)
In Example 22, the tactile sensor 11 was obtained in the same manner as in Example 12. And about the tactile sensor 11 of Example 22, the said (5) stimulus kind test was done. Here, there were three types of stimulation: pressing down the tactile sensor 11 using a human finger, continuously striking the surface of the tactile sensor 11 with a needle, and rubbing the surface of the tactile sensor 11 with a brush. As a result, in Example 22, an impulse response waveform was shown according to various stimuli. Here, the response waveform when the tactile sensor 11 is pushed down with a finger is shown in FIG. 12 (a), the response waveform when it is continuously struck with a needle is shown in FIG. 12 (b), and the response when rubbing with a brush. The waveform is shown in FIG. In FIGS. 10A to 12C, the voltage displacement 32 in the R component and the voltage displacement 33 in the L component and the C component are shown separately.

(A) is a perspective view which shows the tactile sensor of this embodiment, (b) is the schematic which shows a tactile sensor system. (A) is a circuit diagram which shows a mechanical mechanical equivalent circuit, (b) is a circuit diagram which shows an electrical equivalent circuit. (A) And (b) is a circuit diagram which shows an LCR resonance circuit. The principal part expanded sectional view which shows a LCR resonance circuit. (A) And (b) is a perspective view which shows another example of a tactile sensor. (A) And (b) is a principal part expanded sectional view which shows another example of a tactile sensor. Schematic which shows the tactile sensor system with which the tactile sensor was attached to the piezoelectric preload application apparatus. (A)-(f) is a graph which shows a response waveform. (A)-(e) is a graph which shows a response waveform. (A)-(f) is a graph which shows a response waveform. (A)-(f) is a graph which shows a response waveform. (A)-(c) is a graph which shows a response waveform.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Tactile sensor, 12 ... Medium, 13 ... Sensor element, 13a ... Coiled carbon fiber, 14 ... Electrode, 22 ... Inductance (L) component, 23 ... Capacitance (C) component, 24 ... Resistance (R) component, 25 ... LCR resonance circuit.

Claims (10)

A medium that is formed of a dielectric and has a capacitance (C) component and deforms when a contact pressure is applied, and a coiled carbon fiber that is provided in the medium and is based on the helical structure of the coiled carbon fiber A plurality of sensor elements having an inductance (L) component, a capacitance (C) component, and a resistance (R) component and acting as an LCR resonance circuit, and a pair of electrodes electrically connected to the medium ;
The coiled carbon fiber has a coil diameter of 1 nm to 50 μm and a coil length of 10 nm to 10 mm. The content of the sensor element exceeds 1.0% by mass and 10.0% by mass with respect to the medium. A tactile sensor having the following settings . The tactile sensor according to claim 1, wherein the coiled carbon fiber has a crystallized graphite layer . The coating layer which consists of an electroconductive substance is formed in the outer peripheral surface of the said coiled carbon fiber, The said coating layer is formed in the ratio of 1-50 mass% with respect to the coiled carbon fiber. Or the tactile sensor of Claim 2. The tactile sensor according to any one of claims 1 to 3, wherein each of the sensor elements is formed of coiled carbon fibers having different coil diameters. The tactile sensor according to any one of claims 1 to 4, wherein each sensor element is provided in the medium in an oriented state. The tactile sensor according to any one of claims 1 to 5, wherein piezoelectric powder is dispersed in the medium . The liquid silicone resin has an inductance (L) component, a capacitance (C) component, and a resistance (R) component based on the helical structure of the coiled carbon fiber, which is composed of the coiled carbon fiber, and functions as an LCR resonance circuit. A predetermined amount of a plurality of sensor elements is blended, and a mixed solution is prepared by mixing a curing agent and stirred. After filling the mold, the mixed solution is solidified to form a dielectric (C). In the method of manufacturing a tactile sensor, a medium having a component and deformed when a touch pressure is applied is formed, and the medium is taken out from a mold and a pair of electrodes are electrically connected to the medium.
The coiled carbon fiber has a coil diameter of 1 nm to 50 μm and a coil length of 10 nm to 10 mm. The content of the sensor element exceeds 1.0% by mass and 10.0% by mass with respect to the medium. A method for manufacturing a tactile sensor, characterized by being set as follows. The tactile sensor manufacturing method according to claim 7, wherein the coiled carbon fiber has a graphite layer crystallized by subjecting amorphous carbon fiber to heat treatment at 1500 to 3000 ° C. 8. A coating layer made of a conductive material is formed on the outer peripheral surface of the coiled carbon fiber by one method selected from a vapor deposition method, a thermal spraying method, a coating method, a dipping method, and a mechanochemical method. The method for producing a tactile sensor according to claim 7 or 8, wherein the tactile sensor is formed at a ratio of 1 to 50 mass% with respect to the coiled carbon fiber. The tactile sensor manufacturing method according to any one of claims 7 to 9, wherein each sensor element is provided in the medium in an oriented state by applying a magnetic field in which magnetic lines of force extend in one direction. .

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