Capacitive element, proximity sensor, robot, and proximity detection system

Abstract

A capacitive element (2) comprises: a conductive detection electrode (10); a conductive guard electrode (11); and an insulating film that is made of an insulator and has one surface in close contact with one surface of the detection electrode (10) and the other surface in close contact with one surface of the guard electrode (11). The capacitive element (2) is a foldable sheet-like member.

Description

Capacitive element, proximity sensor, robot, proximity detection system

[0001] The present invention relates to a capacitive element, a proximity sensor, a robot, and a proximity detection system.

[0002] Patent Document 1 discloses a proximity sensor that is provided on the outer surface of a robot arm and has a capacitive element made up of a detection electrode that detects an object approaching the arm by a change in electrostatic capacitance.

[0003] JP 2010-10116 A

[0004] The proximity sensor described above has a detection electrode made of a metal plate, which can be damaged by repeated bending and straightening. For this reason, it is difficult to use the capacitance element in a position that is subject to deformation, such as by attaching it across two arms connected to the joints of the arms.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a capacitive element, a proximity sensor, a robot, and a proximity detection system that can be attached to a deforming part and used.

[0006] In order to achieve the above object, a capacitance element according to a first aspect of the present invention is a foldable sheet-like member comprising: a first electrode cloth having conductivity; a second electrode cloth having conductivity; and an insulating film made of an insulator, one side of which is in close contact with one surface of the first electrode cloth and the other side of which is in close contact with one surface of the second electrode cloth.

[0007] A proximity sensor according to a second aspect of the present invention comprises: a capacitive element according to the first aspect of the present invention covering at least a part of an object to be protected; and a detection circuit that detects an object approaching the object to be protected based on a change in the capacitance of the capacitive element.

[0008] A robot according to a third aspect of the present invention comprises: a robot body; a capacitive element according to the first aspect of the present invention that covers at least a portion of the robot body as an object to be protected; and a detection circuit that detects an object approaching the robot body based on a change in capacitance of the capacitive element.

[0009] A robot according to a fourth aspect of the present invention comprises: a robot arm having a first arm, a second arm, and a joint portion connecting the first arm and the second arm; a capacitive element according to the first aspect of the present invention covering the robot arm as an object to be protected; and a detection circuit that detects an object approaching the robot arm based on a change in capacitance of the capacitive element.

[0010] A proximity detection system according to a fifth aspect of the present invention comprises: an object to be protected; a capacitive element according to the first aspect of the present invention covering at least a portion of the object to be protected; and a detection circuit that detects an object approaching the object to be protected based on a change in capacitance of the capacitive element.

[0011] According to the present invention, it can be used by being attached to a deforming part.

[0012] FIG. 1 is a schematic diagram showing the configuration of a proximity sensor according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a state in which a portion of the capacitive element of FIG. 1 is folded back. FIG. 3 is a schematic diagram showing an electric field formed by the capacitive element when an object is not in proximity. FIG. 4 is a schematic diagram showing an electric field formed by the capacitive element when an object is in proximity. FIG. 5 is a schematic diagram showing a case in which the capacitive element is flat. FIG. 6 is a schematic diagram showing a case in which the capacitive element is deformed. FIG. 7 is a schematic diagram of a capacitive element when there is no guard electrode. FIG. 8 is a graph showing an example of change in capacitance over time. FIG. 9 is a first perspective view showing a human-collaborative robot. FIG. 10 is a second perspective view showing a human-collaborative robot. FIG. 11 is a perspective view showing a vertical articulated robot. FIG. 12 is a perspective view showing a SCARA robot. FIG. 13 is a perspective view showing a mobile robot.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same or equivalent parts are designated by the same reference numerals.

[0014] 1, a proximity sensor 1 according to this embodiment detects an approaching object H. The proximity sensor 1 includes a capacitive element 2 and a detection circuit 3. The capacitive element 2 and the detection circuit 3 are electrically connected to each other.

[0015] [Capacitor Element] The capacitor element 2 is a sheet-like member and includes a detection electrode 10 as a first conductive electrode cloth, a guard electrode 11 as a second conductive electrode cloth, and an insulating film 12 made of an insulator.

[0016] [Detection Electrode and Guard Electrode] The detection electrode 10 and the guard electrode 11 are formed from yarns made by drawing fibrous materials in parallel or twisted yarns. The detection electrode 10 and the guard electrode 11 are formed by bonding or intertwining conductive yarns. The detection electrode 10 and the guard electrode 11 may be woven or knitted fabrics made from conductive yarns. The detection electrode 10 and the guard electrode 11 may also be nonwoven fabrics (including felt).

[0017] The threads constituting the detecting electrode 10 and the guard electrode 11 may be made of fibrous resin plated with metal. More specifically, the threads constituting the detecting electrode 10 and the guard electrode 11 may be made of, for example, nylon plated with silver. Alternatively, the threads constituting the detecting electrode 10 and the guard electrode 11 may be made of conductive fibers (for example, fibrous metal). These threads are regularly or irregularly bonded or entangled to be electrically conductive with each other, forming a single sheet of electrode cloth.

[0018] The detection electrode 10 and the guard electrode 11 are soft and thin enough to be foldable. The detection electrode 10 and the guard electrode 11 can be folded back without leaving any gaps. The detection electrode 10 and the guard electrode 11 can be folded back by bending the yarn and deforming the gaps between the yarns.

[0019] In this embodiment, the shape and size of the surface of the detecting electrode 10 are the same as the shape and size of the surface of the guard electrode 11. However, the shape of the surface of the detecting electrode 10 may be different from the shape of the surface of the guard electrode 11, and the size of the surface of the detecting electrode 10 may be smaller than the size of the surface of the guard electrode 11. In this embodiment, the surfaces of the detecting electrode 10 and the guard electrode 11 are shown as rectangular in FIG. 1 , but this is not limiting. Also, in this embodiment, the film thickness of the detecting electrode 10 and the film thickness of the guard electrode 11 are the same, but this is not limiting.

[0020] [Insulating Film] The insulating film 12 is made of a soft material that is flexible and stretchable, and is a film-like member that is thin enough to be folded back without leaving a gap (so that the surfaces before and after the folding point are in contact). The insulating film 12 is made of an insulating material that is flexible and foldable, i.e., can be folded back without leaving a gap. The insulating film 12 is configured to have a uniform film thickness.

[0021] The insulating film 12 can be a film-like member made of resin, rubber, or other elastomers. In this embodiment, however, the insulating film 12 is an insulating cloth made by bonding or intertwining insulating threads. The threads that make up the insulating film 12 are made of resin, such as nylon. These threads are bonded or intertwined with each other in a regular or irregular manner to form a single piece of insulating cloth. The insulating film 12 can be folded back by bending the threads and deforming the gaps between the threads.

[0022] The shape and size of the surface of the insulating film 12 are the same as those of the surfaces of the detection electrode 10 and the guard electrode 11. However, the surface of the insulating film 12 may be larger than the surface of the detection electrode 10. Furthermore, although the shape of the surface of the insulating film 12 is shown as a rectangle in FIG. 1 , this is not limiting. The thickness of the insulating film 12 does not need to be the same as that of the detection electrode 10.

[0023] In FIG. 1 , the detection electrode 10, the guard electrode 11, and the insulating film 12 are illustrated as being shifted in the planar direction. However, in reality, the detection electrode 10, the guard electrode 11, and the insulating film 12 are stacked so that their outer edges are aligned and overlap. One surface of the insulating film 12 is in close contact with one surface of the detection electrode 10. The other surface of the insulating film 12 is in close contact with one surface of the guard electrode 11. In summary, the surface size of the detection electrode 10 is equal to or smaller than the surface size of the insulating film 12, and equal to or smaller than the surface size of the guard electrode 11. Even if the surface sizes are different, the detection electrode 10 is insulated from the guard electrode 11 by the insulating film 12.

[0024] In this embodiment, the insulating film 12 is adhered to the detection electrode 10 and the guard electrode 11 by an adhesive. In FIG. 1 , the adhesive between the insulating film 12 and the detection electrode 10 is shown as an adhesive layer 13, and the adhesive between the insulating film 12 and the guard electrode 11 is shown as an adhesive layer 14. The adhesive layers 13 and 14 are insulating, but may also be conductive. Preferably, the adhesive is a hot-melt adhesive that is melted by applying heat to bond the layers, but other types of adhesives may also be used.

[0025] The detection electrode 10 and the guard electrode 11 may be sewn to the insulating film 12. In this case, they need to be sewn together finely so that no gaps are formed between the opposing surfaces of the detection electrode 10 and the insulating film 12, and between the opposing surfaces of the guard electrode 11 and the insulating film 12, even when the capacitive element 2 is folded.

[0026] As shown in FIG. 2 , the capacitance element 2 is foldable, i.e., configured to be able to be folded back without creating gaps. In other words, the capacitance element 2 has flexibility and thickness that allow it to be folded back. Even when the capacitance element 2 is folded back, the detection electrodes 10 and the insulating film 12 are bonded together with an adhesive, maintaining close contact between the detection electrodes 10 and the insulating film 12, and the guard electrodes 11 and the insulating film 12 are bonded together with an adhesive, maintaining close contact between the guard electrodes 11 and the insulating film 12. This is because the detection electrodes 10, the guard electrodes 11, and the insulating film 12 are formed by bonding or intertwining threads. Therefore, when a portion of the capacitance element 2 is folded back, the gaps between the threads at the folded back portion deform, allowing the capacitance element 2 to deform without generating stress inside the capacitance element 2.

[0027] 1, the guard electrode 11 has a connection terminal 11a. The guard electrode 11 is grounded via the connection terminal 11a. Meanwhile, the detection electrode 10 has a connection terminal 10a, and the detection circuit 3 has a pair of connection terminals 3a and 3b. The detection circuit 3 is connected to the connection terminal 10a of the detection electrode 10 at one connection terminal 3a and is grounded at the other connection terminal 3b.

[0028] 3A and 3B, the capacitive element 2 is used as a cover that protects the object to be protected G. In the capacitive element 2, the guard electrode 11 faces the object to be protected G.

[0029] [Detection Circuit] Returning to FIG. 1 , the detection circuit 3 detects the approach of an object H to the protection target G (see FIGS. 3A and 3B ) based on a change in the capacitance of the capacitance element 2. The detection circuit 3 has an electric circuit that forms a circuit for detecting capacitance in which the capacitance element 2 is incorporated. When the object H approaches the detection electrode 10, the charge on the detection electrode 10 increases, increasing the capacitance of the capacitance element 2, and changing the phase and frequency of the circuit that detects the capacitance. The detection circuit 3 converts this change in phase and frequency of the circuit that detects the capacitance into a change in the capacitance between the detection electrode 10 and the ground, and detects the approach of the object H when the change in capacitance exceeds a threshold. In FIG. 1 , a human hand is shown as the approaching object H. However, the approaching object H is not limited to a human hand.

[0030] 3A , in the capacitive element 2, a capacitor is formed between the detection electrode 10 and the guard electrode 11. A capacitor is also formed between the detection electrode 10 and the ground. However, because the ground is sufficiently far from the detection electrode 10, the capacitance of the capacitor between the detection electrode 10 and the guard electrode 11 is so large that the capacitance of the capacitor between the detection electrode 10 and the ground can be ignored.

[0031] 3B , when an object H approaches the detection electrode 10, a capacitor is formed between the detection electrode 10 and the object H. The capacitance of this capacitor is much larger than the capacitance of the capacitor between the detection electrode 10 and the ground, so the capacitance of the entire capacitive element 2 changes significantly. This change allows the detection circuit 3 to detect that an object is approaching the detection electrode 10.

[0032] 4A, in the capacitance element 2, the area of ​​the detection electrode 10, the guard electrode 11, and the insulating film 12 is S1, and the film thickness of the insulating film 12 is L. In this case, the electrostatic capacitance C between the detection electrode 10 and the guard electrode 11 is expressed by the following equation: C=ε ０ ・ε Ｓ (S1 / L) (1) where ε ０ is the dielectric constant of a vacuum, and ε Ｓ is the dielectric constant of the insulating film 12.

[0033] 4B , even if a portion of the capacitance element 2 is deformed and wrinkled, the area S1 of the portion where the detection electrode 10 and the guard electrode 11 face each other (effective area that determines the capacitance) does not change, and the distance L between the detection electrode 10 and the guard electrode 11 does not change either. Therefore, the capacitance of the capacitor formed by the detection electrode 10 and the guard electrode 11 does not change. In other words, regardless of the deformation of the capacitance element 2, the capacitance element 2 can accurately determine whether or not an object H is approaching.

[0034] 4C , when the guard electrode 11 is removed from the capacitance element 2, the effective area of ​​the detection electrode 10, which determines the capacitance of the capacitance element 2, changes from S1 to S2. Therefore, without the guard electrode 11, the capacitance of the entire capacitance element 2 changes significantly even if the object H is not in proximity. This change becomes an error component included in the detection signal used to determine whether the object H is in proximity.

[0035] 5, when the capacitive element 2 is deformed as shown in FIG. 4B, for example, the deformation causes a slight variation in the capacitance of the entire capacitive element 2 detected by the detection circuit 3. The range of this variation is indicated by a gray zone in FIG. 5. In this case, a first threshold value greater than the level of this variation range must be set as the threshold value for determining whether or not the object H is approaching.

[0036] When the capacitance element 2 according to this embodiment is caused to detect the presence or absence of the approaching object H, the capacitance of the entire capacitance element 2 detected by the detection circuit 3 increases. If this capacitance exceeds the first threshold value, it can be detected that the object H is approaching. In the graph shown in FIG. 5 , the time point at which it is determined that the object H is approaching is indicated as time t1.

[0037] Here, if the guard electrode 11 is removed, the capacitance of the entire capacitive element 2 will fluctuate significantly. Therefore, as a threshold for determining whether or not the object H is approaching, it is necessary to set a second threshold that is even higher than the first threshold that exceeds the range of variation. In this case, the time at which it is determined that the object H is approaching is time t2, which is later than time t1. This indicates that the spatial range in which it is possible to determine whether or not the object H is approaching is narrowed.

[0038] As described above, the capacitive element 2 according to the present embodiment includes the guard electrode 11, which suppresses fluctuations in the capacitance of the capacitive element 2 and stabilizes it. Therefore, the threshold value for determining whether or not the object H is approaching is set to the first threshold value, which widens the detection area in which the presence or absence of the object H can be detected, thereby enabling the proximity of the object H to be detected quickly.

[0039] [Example of Use] The capacitive element 2 functions as a cover that covers at least a part of a protected object with the guard electrode 11 facing the protected object (with the guard electrode 11 facing inside). For example, as shown in Figures 6A and 6B, 7 and 8, the capacitive element 2 can be used as a cover for an articulated robot.

[0040] 6A , the capacitive element 2 according to this embodiment can be used as a cover for a human-collaborative robot 20. The human-collaborative robot 20 is a robot designed to be able to work together with humans while sharing the same space, without the need for isolation by a fence for safety. Because the human-collaborative robot 20 shares the same space as humans, it is desirable to use the capacitive element 2 as a cover to detect proximity to a human in order to avoid contact with the human.

[0041] In Fig. 6A, the capacitive element 2 is transparent. As shown in Fig. 6A, the human-collaborative robot 20 includes a base unit 20a, a plurality of joint units 20b to 20e, arm units 21a to 21d, and a hand unit 22. The base unit 20a and the joint units 20b to 20e each have a built-in motor, and when the motor is driven, the position and posture of the connected arm units 21a to 21d (first arm, second arm) and the hand unit 22 at the tip can be changed. In summary, the human-collaborative robot 20 is a robot arm having a base unit 20a, arm units 21a to 21d, a joint unit 20b connecting arm unit 21a and arm unit 21b, a joint unit 20c connecting arm unit 21b and arm unit 21c, a joint unit 20d connecting arm unit 21c and arm unit 21d, and a hand unit 22 connected to arm unit 21d via joint unit 20e.

[0042] As shown in FIG. 6B , the capacitive element 2 covers the entire human-collaborative robot 20 except for the hand unit 22. The capacitive element 2 has a through-hole 2a through which the hand unit 22 protrudes to the outside, enabling operation. The capacitive element 2 is sized to have a certain degree of margin relative to the human-collaborative robot 20. Even when the human-collaborative robot 20 deforms, the capacitive element 2 deforms to match the human-collaborative robot 20. Even during this deformation, the capacitance of the capacitive element 2 does not change significantly unless another object (e.g., a person) H (see FIG. 1 ) approaches. When the object H approaches, the capacitance of the capacitive element 2 changes significantly. This makes it possible to detect the approach of the object H.

[0043] The capacitance element 2 can also be used as a cover for a vertical articulated robot 23 shown in FIG. 7 and a SCARA robot 25 shown in FIG. 8. In both FIGS. 7 and 8, the cover (capacitance element 2) is illustrated as being transparent. As shown in FIG. 7, the vertical articulated robot 23 has a base 23a, arms 23b and 23c, and a hand 24. Joints incorporating motors are provided between the base 23a and the arm 23b, between the arm 23b and the arm 23c, and between the arm 23c and the hand 24. As shown in FIG. 8, the SCARA robot 25 has a base 25a, arms 25b and 25c, and a hand 26. Joints incorporating motors are provided between the base 25a and the arm 25b, between the arm 25b and the arm 25c, and between the arm 25c and the hand 26.

[0044] 7 and 8, the capacitance element 2 is sized to have a sufficient margin relative to the vertical articulated robot 23 and the SCARA robot 25, and covers the vertical articulated robot 23 and the SCARA robot 25 with their respective hand units 24, 26 protruding to the outside through the through-holes 2a. Therefore, even if the joints of the vertical articulated robot 23 and the SCARA robot 25 rotate, the capacitance element 2 deforms to match the shape of the robot. Even during this deformation, the capacitance of the capacitance element 2 does not change significantly unless another object H (see FIG. 1, for example, a person) is brought close.

[0045] The capacitance element 2 can also be used as a cover for a mobile robot 27 as shown in FIG. 9. The mobile robot 27 includes a robot body 27a and wheels 27b for movement. The robot body 27a is provided with a drive unit that rotates the wheels 27b, and the robot moves by driving the wheels 27b. The mobile robot 27 has functions suited to its intended use, such as monitoring the surroundings, cleaning the floor, or serving food. The capacitance element 2 is attached to at least a part of the robot body 27a, for example, to the side surface. The proximity of an object H (see FIG. 1) to the robot body 27a can be detected by a change in the electrostatic capacitance of the capacitance element 2.

[0046] In the above embodiment, the capacitance element 2 is formed by attaching the detection electrode 10 and guard electrode 11 made of conductive thread and the insulating film 12 made of insulating thread to an adhesive material. However, this is not limiting. The capacitance element 2 may be formed by knitting or weaving a combination of conductive thread and insulating thread, so that a layer made of insulating thread is formed between two layers made of conductive thread.

[0047] Furthermore, when the object to be protected G is large, the entire cover may be formed by connecting a plurality of capacitive elements 2. In this case, a detection circuit 3 is formed for each capacitive element 2. In this case, the capacitive elements 2 may be connected to each other with adhesive or by sewing.

[0048] [Summary] (1) As described above in detail, the capacitance element 2 according to this embodiment is a foldable sheet-like member that includes a conductive detection electrode 10, a conductive guard electrode 11, and an insulating film 12 made of an insulator, one surface of which is in close contact with one surface of the detection electrode 10 and the other surface of which is in close contact with one surface of the guard electrode 11. In this way, even if the object to be protected G deforms, the capacitance element 2 can cover the object to be protected G while freely deforming in response to the deformation, and therefore can be attached to a deforming part for use.

[0049] (2) In the capacitance element 2 according to this embodiment, the detection electrode 10 and the guard electrode 11 are formed by bonding or intertwining conductive threads. This allows the capacitance element 2 to be bent smoothly by bending the threads and deforming the gaps between the threads.

[0050] (3) In the capacitive element 2 according to this embodiment, the insulating film 12 is an insulating cloth formed by bonding or intertwining insulating threads. This allows the insulating cloth to bend the threads and deform the gaps between the threads, thereby allowing the capacitive element 2 to be bent smoothly.

[0051] (4) In the capacitive element 2 according to this embodiment, the insulating film 12 may be made of a flexible, foldable insulating material. In other words, it is not limited to an insulating cloth made of thread.

[0052] (5) In the capacitive element 2 according to this embodiment, the insulating film 12 has a uniform thickness. This reduces variations in capacitance depending on the location where the object H is in proximity.

[0053] (6) In the capacitive element 2 according to this embodiment, the detection electrode 10 and the guard electrode 11 are adhered to the insulating film 12. In this manner, the detection electrode 10 and the insulating film 12 are closely attached to each other, and the capacitive element 2 can be deformed while the guard electrode 11 and the insulating film 12 are closely attached to each other.

[0054] (7) In the capacitive element 2 according to this embodiment, the detection electrode 10 and the guard electrode 11 may be sewn to the insulating film 12. By sewing these together, the capacitive element 2 can be used even in an environment where the use of adhesive is undesirable.

[0055] (8) In the capacitive element 2 according to this embodiment, the guard electrode 11 faces the object to be protected (with the guard electrode 11 facing inward) and functions as a cover that covers at least a part of the object to be protected G. In other words, the capacitive element 2 can be used as a cover that protects the object to be protected G.

[0056] (9) The proximity sensor 1 according to this embodiment may include a capacitive element 2 and a detection circuit 3 that detects the approach of an object H to a protection target G based on a change in the electrostatic capacitance of the capacitive element 2. This proximity sensor 1 may be used for any object G to be protected, such as a stationary object or a moving object.

[0057] (10) The robot according to this embodiment may include a robot body 27a of a mobile robot 27, a capacitance element 2 that covers at least a portion of the robot body 27a as a protected object G, and a detection circuit 3 that detects the approach of an object H to the robot body 27a based on a change in the capacitance of the capacitance element 2.

[0058] (11) The human-collaborative robot 20 according to this embodiment may include robot arms (20a to 20e, 21a to 21d, 22) having an arm portion 21a, an arm portion 21b, and a joint portion 20b connecting the arm portion 21a and the arm portion 21b; a capacitive element 2 that covers the robot arms (20a to 20e, 21a to 21d, 22) as objects to be protected; and a detection circuit 3 that detects the approach of an object H to the robot arms (20a to 20e, 21a to 21d, 22) based on a change in the capacitance of the capacitive element 2.

[0059] (12) The proximity detection system according to this embodiment includes a protection target G, a capacitive element 2 that covers at least a portion of the protection target G, and a detection circuit 3 that detects the proximity of an object H to the protection target G based on a change in the electrostatic capacitance of the capacitive element 2. In this way, the protection target G is not limited to a robot, and the system can be applied to any protection target G, including moving objects such as vehicles and drones, and stationary objects.

[0060] This invention allows various embodiments and modifications without departing from the broad spirit and scope of this invention. Furthermore, the above-described embodiments are intended to explain this invention and do not limit the scope of this invention. That is, the scope of this invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the invention equivalent thereto are considered to be within the scope of this invention.

[0061] In addition, this application claims priority based on Japanese Patent Application No. 2023-127034 filed on August 3, 2023, and the specification, claims, and drawings of Japanese Patent Application No. 2023-127034 are incorporated herein by reference.

[0062] The present invention can be applied to detecting objects.

[0063] 1 proximity sensor, 2 capacitance element, 2a through hole, 3 detection circuit, 3a connection terminal, 3b connection terminal, 10 detection electrode (first electrode cloth), 10a connection terminal, 11 guard electrode (second electrode cloth), 11a connection terminal, 12 insulating film, 13, 14 adhesive layer, 20 human collaborative robot, 20a base portion, 20b, 20c, 20d, 20e joint portion, 21a, 21b, 21c, 21d arm portion (first arm, second arm), 22 hand portion, 23 vertical articulated robot, 23a base portion, 23b, 23c arm portion, 24 hand portion, 25 SCARA robot, 25a base portion, 25b, 25c arm portion, 26 hand portion, 27 mobile robot, 27a robot body, 27b wheel, 50 proximity detection system, G protected object, H object

Claims

1. A capacitive element comprising: a first electrode cloth having electrical conductivity; a second electrode cloth having electrical conductivity; and an insulating film made of an insulator, one side of which is in close contact with one side of the first electrode cloth and the other side of which is in close contact with one side of the second electrode cloth, said element being a foldable sheet-like member.

2. The capacitance element according to claim 1, wherein the first electrode cloth and the second electrode cloth are formed by bonding or intertwining conductive threads.

3. The capacitive element according to claim 1, wherein the insulating film is an insulating cloth made by bonding or intertwining insulating threads together.

4. The capacitive element according to claim 1, wherein the insulating film is made of a flexible, foldable insulating material.

5. The capacitive element according to claim 1, wherein the insulating film is configured to have a uniform thickness.

6. The capacitance element according to claim 1, wherein the first electrode cloth and the second electrode cloth are adhered to the insulating film.

7. The capacitance element according to claim 3, wherein the first electrode cloth and the second electrode cloth are sewn to the insulating cloth.

8. A capacitive element according to any one of claims 1 to 7, wherein the second electrode cloth faces an object to be protected and functions as a cover that covers at least a portion of the object to be protected.

9. A proximity sensor comprising: a capacitive element according to claim 8 that covers at least a part of an object to be protected; and a detection circuit that detects the approach of an object to the object to be protected based on a change in capacitance of the capacitive element.

10. A robot comprising: a robot body; a capacitive element as described in claim 8 that covers at least a portion of the robot body as an object to be protected; and a detection circuit that detects the approach of an object to the robot body based on a change in capacitance of the capacitive element.

11. A robot comprising: a robot arm having a first arm, a second arm, and a joint connecting the first arm and the second arm; a capacitive element as described in claim 8 that covers the robot arm as an object to be protected; and a detection circuit that detects the approach of an object to the robot arm based on a change in capacitance of the capacitive element.

12. A proximity detection system comprising: an object to be protected; a capacitive element according to claim 8 covering at least a portion of the object to be protected; and a detection circuit that detects the proximity of an object to the object to be protected based on a change in capacitance of the capacitive element.

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