Load sensor

Abstract

The load sensor comprises: a first substrate and a second substrate arranged face-to-face; a conductive elastomer disposed on the opposing surface of the first substrate; and conductor wires (13a, 13b) disposed between the second substrate and the conductive elastomer, and is formed by twisting together a plurality of wires (30). The wires (30) are formed by coating the surface of a linear conductive member (31) with a dielectric (32). The twist pitch of the plurality of wires (30) satisfies the condition "p ≤ 12nd". In the above formula, p is the twist pitch of the plurality of wires (30), n is the number of wires (30) contained in the conductor wires (13a, 13b), and d is the outer diameter of the wires (30).

Description

Technical Field

[0001] This invention relates to a load sensor that detects externally applied loads based on changes in electrostatic capacitance. Background Technology

[0002] Load sensors are widely used in industrial equipment, robotics, and vehicles. In recent years, the development of computer-based control technology and the improvement of aesthetics have driven the development of electronic devices that utilize freeform surfaces in various forms, such as humanoid robots and automotive interior decorations. Correspondingly, there is a growing demand for equipping high-performance load sensors on various freeform surfaces.

[0003] Patent Document 1 describes a pressure-sensitive element comprising a sensor portion for imparting pressure and a detector for detecting pressure. In this pressure-sensitive element, the sensor portion includes a first conductive member, a second conductive member sandwiched between the first conductive member and a substrate, and a dielectric. The first conductive member is elastic. The second conductive member is configured as a line and is arranged in a wavy pattern along a fixed main direction. The dielectric is disposed between the first and second conductive members, at least partially covering the surface of either the first or second conductive member. The detector detects the pressure based on the change in electrostatic capacitance between the first and second conductive members.

[0004] Prior technology documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2018 / 096901 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In the structure described above, if the second conductive member is formed by stranding multiple linear members together, the bending strength of the second conductive member can be improved. However, in this case, if the sensor section is repeatedly subjected to a load, thereby releasing the stranded state, the relationship between the load and the electrostatic capacitance between the first and second conductive members will change. As a result, the load can no longer be properly detected.

[0009] In view of the relevant issues, the object of the present invention is to provide a load sensor that can employ stranded wires and appropriately detect loads.

[0010] Methods for solving problems

[0011] The first aspect of the present invention relates to a load sensor. The load sensor of this aspect comprises: a first substrate and a second substrate disposed face-to-face; a conductive elastomer disposed on the opposing surface of the first substrate; and conductor wires disposed between the second substrate and the conductive elastomer, formed by twisting together a plurality of wires. The wires are formed by coating the surface of a linear conductive member with a dielectric material, and the twist pitch of the plurality of wires satisfies the following conditional expression.

[0012] p≤12nd

[0013] Here, the parameters shown in the above equations are defined as follows.

[0014] p: Twist pitch of multiple wires

[0015] n: The number of wires contained in the conductor wire

[0016] d: Outer diameter of the wire

[0017] According to the load sensor described in this method, the twist pitch of multiple wires is configured to satisfy the above formula. Therefore, since wire untwisting is suppressed, the change in electrostatic capacitance between the conductive elastomer and the conductive member is suppressed. Thus, load can be appropriately detected while using a conductor wire (stranded wire) formed by twisting multiple wires together.

[0018] The effects of the invention

[0019] As described above, according to the present invention, a load sensor that can use stranded wire and appropriately detect load can be provided.

[0020] The effects or significance of the present invention will become clearer through the following description of the embodiments. However, the embodiments shown below are merely examples of implementing the present invention, and the present invention is not limited to any of the solutions described in the following embodiments. Attached Figure Description

[0021] Figure 1 (a) is a perspective view schematically showing the lower substrate and the conductive elastomer disposed on the opposing surface of the lower substrate according to Embodiment 1. Figure 1 (b) is a perspective view schematically representing a pair of conductor wires and a filament (wire) according to Embodiment 1.

[0022] Figure 2 (a) is a perspective view schematically showing the upper substrate and the conductive elastomer disposed on the opposite surface of the upper substrate according to Embodiment 1. Figure 2 (b) is a perspective view schematically showing the assembled load sensor according to Embodiment 1.

[0023] Figure 3 (a) is a perspective view schematically showing the structure of the conductor wire involved in Embodiment 1. Figure 3 (b) is a schematic diagram of the cross section of the conductor line cut in the direction of rotation axis by a plane perpendicular to the rotation axis, according to Embodiment 1.

[0024] Figure 4 (a) and (b) are schematic cross-sectional views of the periphery of the conductor line as shown in the negative X-axis direction according to Embodiment 1.

[0025] Figure 5 This is a top view of the interior of the load sensor as shown in the negative Z-axis direction according to Embodiment 1.

[0026] Figure 6 (a) is a cross-sectional view of the periphery of the conductor line in the case of Comparative Example 1, viewed in the negative X-axis direction. Figure 6 (b) is a diagram illustrating the change in electrostatic capacitance involved in Comparative Example 1.

[0027] Figure 7 (a) is a table showing the verification results of the twist pitch involved in Implementation 1. Figure 7 (b) is a diagram illustrating the change in electrostatic capacitance as described in Implementation 1.

[0028] Figure 8 This is a diagram used to illustrate the spacing of the conductor lines and the width of the sensor section in Embodiment 2.

[0029] Figure 9 This is a graph showing the verification results of the conductor spacing involved in Implementation Method 2.

[0030] Figure 10 (a) is a top view schematically showing the interior of the load sensor as described in Embodiment 2, viewed in the negative Z-axis direction. Figure 10 (b) is a top view of the interior of the load sensor, which is shown in the negative Z-axis direction in Comparative Example 2.

[0031] Figure 11 This is a flowchart illustrating the steps of the manufacturing method for the load sensor involved in the modified example.

[0032] Figure 12 (a) and (b) are schematic diagrams illustrating the manufacturing process of the load sensor involved in the modified example.

[0033] Figure 13 (a) and (b) are schematic diagrams illustrating the manufacturing process of the load sensor involved in the modified example.

[0034] Figure 14 This is a top view schematically illustrating the manufacturing method of the load sensor involved in Comparative Example 3.

[0035] Figure 15 This is a top view showing the structure of the clamp (jig) used to form a pair of conductor wires involved in the modified example.

[0036] Figure 16 (a) to (d) are top views of the modified example, illustrating the steps of using a clamp to form a pair of conductor wires.

[0037] Figure 17 This is a schematic diagram illustrating the internal structure of a load sensor in a modified example where the load sensor is positioned on the toilet seat.

[0038] Figure 18 (a) is a perspective view schematically representing the lower substrate and conductive elastomer involved in Reference Example 1. Figure 18 (b) is a schematic perspective view of the copper-coated wire and the wire involved in Reference Example 1.

[0039] Figure 19 (a) is a perspective view schematically representing the upper substrate and conductive elastomer involved in Reference Example 1. Figure 19 (b) is a perspective view schematically representing the assembled load sensor involved in Reference Example 1.

[0040] Figure 20 (a) and (b) are schematic cross-sectional views of the periphery of the copper-clad wires, taken in the negative X-axis direction as described in Reference Example 1.

[0041] Figure 21 This is a top view of the interior of the load sensor, as shown in Reference Example 1, viewed in the negative Z-axis direction.

[0042] Figure 22 This is a top view schematically illustrating the specific structure of the load sensor involved in Reference Example 1.

[0043] Figure 23 (a) and (b) are cross-sectional views of the section cut in the positive Y-axis direction at the location of the copper-coated wire with a plane parallel to the XZ plane, as described in Comparative Example 1.

[0044] Figure 24 (a) and (b) are cross-sectional views of the section cut in the positive Y-axis direction at the location of the copper-coated wire with a plane parallel to the XZ plane, as described in Comparative Example 2.

[0045] Figure 25 (a) and (b) are cross-sectional views of the section cut in the positive Y-axis direction at the location of the copper-coated wire with a plane parallel to the XZ plane, as described in Reference Example 1.

[0046] Figure 26 This is a top view schematically illustrating the specific structure of the load sensor involved in Reference Example 2.

[0047] Figure 27 (a) is the A-A' cross-sectional view of the load sensor in Reference Example 2, where the load sensor is cut off by the XZ plane passing through the joint located on the negative side of the Y-axis. Figure 27 (b) is a table showing the verification results conducted by the inventors in Reference Example 2.

[0048] Figure 28 This is a top view schematically illustrating the specific structure of the load sensor involved in Reference Example 3.

[0049] Figure 29 (a) is a top view of the outer periphery of the substrate on the negative Y-axis side, as described in Reference Example 3, viewed in the negative Z-axis direction. Figure 29 (b) is a cross-sectional view of the load sensor cut off by the XZ plane passing through the pinhole, as described in Reference Example 3.

[0050] Figure 30 (a) is a top view of the outer periphery of the substrate on the negative Y-axis side, as described in Comparative Example 3, viewed in the negative Z-axis direction. Figure 30 (b) is a cross-sectional view of the load sensor cut off by the XZ plane passing through the pinhole, as described in Comparative Example 3.

[0051] Figure 31 (a) is a top view of the outer periphery of the substrate on the negative Y-axis side, as described in Modification Example 1, viewed in the negative Z-axis direction. Figure 31 (b) is the D-D' cross-sectional view of the load sensor when it is cut off by the XZ plane passing through the pinhole, as involved in the modified example 1.

[0052] Figure 32 (a) is a top view of the outer periphery of the substrate on the negative Y-axis side, as described in the negative Z-axis direction, in the case of Modification Example 2. Figure 32 (b) is a top view of the outer periphery of the substrate on the negative Y-axis side, as described in Modification Example 3, viewed in the negative Z-axis direction.

[0053] However, the accompanying drawings are for illustrative purposes only and do not limit the scope of the invention. Detailed Implementation

[0054] The load sensor involved in this invention can be used as a load sensor in management systems and electronic devices that process the assigned load.

[0055] Examples of management systems include inventory management systems, driver monitoring systems, instruction management systems, security management systems, and nursing / childcare management systems.

[0056] In inventory management systems, for example, load sensors installed on shelves detect the load of the loaded inventory, thereby identifying the type and quantity of goods present on the shelves. This allows for efficient inventory management and labor savings in stores, factories, and warehouses. Furthermore, load sensors installed inside refrigerators detect the load of food inside, thereby identifying the type, quantity, and type of food. This allows for the automatic creation of recipes utilizing the food stored in the refrigerator.

[0057] In driver monitoring systems, for example, load sensors located on the steering mechanism monitor the driver's load distribution on the steering system (e.g., grip force, grip position, pedal force). Furthermore, load sensors located on the vehicle seat monitor the driver's load distribution on the seat while seated (e.g., center of gravity position). This allows for feedback on the driver's driving state (drowsiness, psychological state, etc.).

[0058] In guidance and management systems, for example, load sensors installed on the soles of shoes can monitor the load distribution on the soles of the feet. This allows for correction or guidance of appropriate walking or running patterns.

[0059] In security management systems, for example, load sensors installed on the floor can detect load distribution, weight, stride length, speed, and shoe sole patterns as a person passes by. By comparing this detection information with data, the person passing by can be identified.

[0060] In nursing / childcare management systems, for example, load sensors installed on bedding and toilet seats can monitor the load distribution of the human body on these surfaces. This allows for the estimation of how a person should act based on the location of the bedding and toilet seat, thus preventing falls.

[0061] Examples of electronic devices include in-vehicle devices (navigation systems, audio equipment, etc.), home appliances (electric kettles, IH cooking heaters, etc.), smartphones, e-paper devices, e-book readers, PC keyboards, game controllers, smartwatches, wireless headphones, touch panels, electronic pens, flashlights, light-up clothing, musical instruments, etc. In electronic devices, a load sensor is installed at the input section that receives input from the user.

[0062] The load sensor in the following embodiments is a capacitive load sensor typically installed in the load sensors of management systems and electronic devices described above. Such load sensors are sometimes also referred to as "capacitive pressure sensor elements," "capacitive pressure detection sensor elements," or "pressure-sensitive switch elements." Furthermore, the load sensor in the following embodiments is connected to a detection circuit, and a load detection device is constructed by the load sensor and the detection circuit. The following embodiments are one embodiment of the present invention, and the present invention is not limited to any of the following embodiments.

[0063] The embodiments of the present invention will be described below with reference to the accompanying drawings. For convenience, the mutually orthogonal X, Y, and Z axes are indicated in each figure. The Z-axis direction is the height direction of the load sensor 1.

[0064] <Implementation Method 1>

[0065] refer to Figure 1 (a)~ Figure 5 To illustrate the structure of load sensor 1.

[0066] Figure 1 (a) is a perspective view schematically showing the substrate 11 and three conductive elastomers 12 disposed on the opposing surface 11a (the surface on the positive side of the Z-axis) of the substrate 11.

[0067] The substrate 11 is an elastic insulating component having a flat plate shape parallel to the XY plane. The substrate 11 is made of a non-conductive resin material or a non-conductive rubber material. The resin material used in the substrate 11 is, for example, at least one resin material selected from the group including styrene-based resins, silicone-based resins (such as polydimethylpolysiloxane (PDMS), etc.), acrylic resins, rotaxane-based resins, and urethane-based resins. The rubber material used in the base material 11 is, for example, at least one rubber material selected from the group including silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber, and natural rubber.

[0068] A conductive elastomer 12 is formed on the opposing surface 11a (the surface on the positive Z-axis side) of the substrate 11. Figure 1In (a), three conductive elastomers 12 are formed on the opposing surface 11a of the substrate 11. Each conductive elastomer 12 is an elastic, conductive component. Each conductive elastomer 12 has a long, strip-like shape in the Y-axis direction and is arranged at a given interval in the X-axis direction. A cable 12a, electrically connected to the conductive elastomer 12, is provided at the end of each conductive elastomer 12 on the negative Y-axis side.

[0069] The conductive elastomer 12 is formed on the opposing surface 11a of the substrate 11 by printing methods such as screen printing, gravure printing, flexographic printing, offset printing, and gravure-offset printing. Through these printing methods, the conductive elastomer 12 can be formed on the opposing surface 11a of the substrate 11 with a thickness of 0.001 mm to 0.5 mm.

[0070] The conductive elastomer 12 is composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein.

[0071] The resin material used in the conductive elastomer 12 is the same as the resin material used in the substrate 11 described above, and is, for example, at least one resin material selected from the group including styrene-based resins, silicone-based resins (polydimethylpolysiloxane (e.g., PDMS), acrylic resins, rotaxane-based resins, and urethane-based resins. The rubber material used in the conductive elastomer 12 is the same as the rubber material used in the substrate 11 described above, and is, for example, at least one rubber material selected from the group including silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber, and natural rubber.

[0072] The conductive filler used in the conductive elastomer 12 is selected from at least one material from the group including metal materials such as Au (gold), Ag (silver), Cu (copper), C (carbon), ZnO (zinc oxide), In2O3 (indium oxide (III)) and SnO2 (tin oxide (IV)), conductive polymer materials such as PEDOT:PSS (i.e., a composite containing poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS), metal-coated organic fibers, conductive fibers such as metal wires (fiber state).

[0073] Figure 1 (b) is a schematic representation of a container placed on Figure 1 A three-dimensional view of the structure of (a) consisting of three pairs of conductor wires 13 and 12 filaments 14.

[0074] A pair of conductor lines 13 are formed by connecting the ends of two conductor lines 13a and 13b arranged at a given interval on the positive side of the X-axis. The pair of conductor lines 13 are arranged overlappingly. Figure 1 The upper surfaces of the three conductive elastomers 12 are shown in (a). Here, three sets of pairs of conductor wires 13 are overlapped on the upper surfaces of the three conductive elastomers 12. The three sets of pairs of conductor wires 13 are arranged to intersect the conductive elastomers 12 and are arranged at a given interval along the long side direction (Y-axis direction) of the conductive elastomers 12. The pairs of conductor wires 13 extend in the X-axis direction so as to cross the three conductive elastomers 12. The conductor wires 13a and 13b are composed of linear conductive members and a dielectric covering the surface of the conductive members. The structure of the conductor wires 13a and 13b will be referred to later. Figure 3 Let's explain using (a) and (b).

[0075] like Figure 1 As in (b), after arranging three sets of a pair of conductor wires 13, each pair of conductor wires 13 is movable on the substrate 11 in the direction (X-axis direction) in which the pair of conductor wires 13 extend, via a wire 14. Figure 1 In the example shown in (b), 12 filaments 14 connect the pair of conductor wires 13 to the substrate 11 at locations other than where the conductive elastomer 12 overlaps with the pair of conductor wires 13. The filaments 14 are made of chemical fibers, natural fibers, or a mixture thereof.

[0076] Figure 2 (a) is a perspective view schematically showing the substrate 21 overlapping on the upper side of the substrate 11 and the three conductive elastomers 22 disposed on the opposing surface 21a (the surface on the negative side of the Z-axis) of the substrate 21.

[0077] Substrate 21 has the same size and shape as substrate 11 and is made of the same material as substrate 11. Conductive elastomers 22 are formed on the opposing surface 21a (the negative Z-axis surface) of substrate 21 at a position opposite to conductive elastomer 12, arranged at given intervals in the X-axis direction. Conductive elastomers 22 have the same size and shape as conductive elastomer 12 and are made of the same material as conductive elastomer 12. Like conductive elastomer 12, conductive elastomers 22 are formed on the negative Z-axis surface of substrate 21 using a given printing method. Cables 22a electrically connected to conductive elastomer 22 are provided at the negative Y-axis end of each conductive elastomer 22.

[0078] Figure 2 (b) is a schematic representation of... Figure 1 (b) Construct settings Figure 2 A three-dimensional diagram of the state of the construct of (a).

[0079] from Figure 1The structure shown in (b) is positioned above (positive Z-axis side) the top of it. Figure 2 The structure shown in (a) is as follows. In this case, substrate 11 and substrate 21 are arranged such that opposing surfaces 11a and 21a face each other, and conductive elastomers 12 and 22 are arranged overlappingly. Then, substrate 11 and substrate 21 are fixed by connecting the outer periphery of substrate 21 relative to the outer periphery of substrate 11 using a silicone rubber adhesive, thread, etc. Thus, the three sets of one pair of conductor wires 13 are sandwiched between three conductive elastomers 12 and three conductive elastomers 22. Thus, as... Figure 2 As shown in (b), load sensor 1 is completed.

[0080] Figure 3 (a) is a perspective view schematically showing the structure of conductor lines 13a and 13b. Conductor lines 13a and 13b have the same structure.

[0081] Conductor wires 13a and 13b are constructed by twisting together multiple wires 30. That is, conductor wires 13a and 13b are stranded wires formed by rotating multiple wires 30 around a central axis 30a with the direction in which the conductor wires 13a and 13b extend as the central axis 30a. Figure 3 In (a), seven wires 30 are twisted together. If multiple wires 30 are twisted together in this way, the multiple wires 30 are intertwined. As shown by the dotted line, the distance along the central axis 30a from which any wire 30 rotates about the central axis 30a until it returns to the same rotational position is the twist pitch p. The setting value of the twist pitch p will be referred to later. Figure 7 Explain (a).

[0082] Figure 3 (b) is cut off by a plane perpendicular to the central axis 30a when viewed in the direction of the central axis 30a. Figure 3 A schematic diagram of the cross-sections of conductor lines 13a and 13b in (a).

[0083] If multiple wires are twisted together appropriately, then as follows: Figure 3 As shown in (b), multiple wires 30 are arranged approximately symmetrically around a central axis 30a. Each wire 30 consists of a linear conductive member 31 and a dielectric 32 covering the surface of the conductive member 31. The outer diameter (diameter) of the wire 30 is d. The setting value of the outer diameter d will be referred to later. Figure 7 Explain (a).

[0084] The conductive member 31 is made of, for example, a conductive metallic material. Alternatively, the conductive member 31 can be made of a glass core wire and a conductive layer formed on its surface, or of a resin core wire and a conductive layer formed on its surface. In Embodiment 1, the conductive member 31 is made of copper.

[0085] The dielectric 32 has electrical insulation properties and is made of, for example, resin materials, ceramic materials, metal oxide materials, etc. The dielectric 32 may be at least one resin material selected from the group including polypropylene resin, polyester resin (e.g., polyethylene terephthalate resin), polyimide resin, polyphenylene sulfide resin, polyvinyl alcohol formaldehyde resin, polyurethane resin, polyamide-imide resin, polyamide resin, etc., or at least one metal oxide material selected from the group including Al2O3 and Ta2O5, etc.

[0086] Figure 4 (a) and (b) are schematic cross-sectional views of the periphery of conductor lines 13a and 13b when viewed in the negative X-axis direction. Figure 4 (a) indicates the state without load applied. Figure 4 (b) indicates the state in which a load is applied. For convenience, the following description explains the case in which a load is applied to conductor 13a.

[0087] In the absence of Figure 4 When a load is applied to the region shown in (a), the force applied between the conductive elastomer 12 and the conductor wire 13a, and the force applied between the conductive elastomer 22 and the conductor wire 13a, are approximately zero. If from this state onwards... Figure 4 As shown in (b), when a load is applied upward to the lower surface of substrate 11 and downward to the upper surface of substrate 21, the conductive elastomers 12 and 22 will deform due to the conductor wire 13a. Furthermore, when a stationary object is placed on the lower surface of substrate 11 or the upper surface of substrate 21 and a load is applied only to the other substrate, a load is also applied from the stationary object side through a reaction.

[0088] like Figure 4 As shown in (b), when a load is applied, conductor 13a moves closer to conductive elastomers 12 and 22, increasing the contact area between conductor 13a and conductive elastomers 12 and 22, which are encased in them. Similarly, conductor 13b moves closer to conductive elastomers 12 and 22, increasing the contact area between conductor 13b and conductive elastomers 12 and 22, which are encased in them. This causes changes in the electrostatic capacitance between conductive member 31 and conductive elastomer 12, and between conductive member 31 and conductive elastomer 22. The load applied to the region is then calculated by detecting the electrostatic capacitance of the regions of conductors 13a and 13b.

[0089] Figure 5 This is a top view schematically showing the interior of load sensor 1 when viewed in the negative Z-axis direction. Figure 5For convenience, the illustration of thread 14 is omitted.

[0090] Nine sensor units are arranged in the X-axis and Y-axis directions within the measurement area R of the load sensor 1. Specifically, the measurement area R is divided into three parts in the X-axis direction and three parts in the Y-axis direction, resulting in nine regions, which are then assigned to the nine sensor units. The boundary of each sensor unit is connected to the boundary of the sensor unit adjacent to it. The nine sensor units correspond to nine locations where they intersect with the conductive elastomers 12 and 22 and a pair of conductor lines 13, forming nine sensor units A11, A12, A13, A21, A22, A23, A31, A32, and A33 at these nine locations, corresponding to changes in electrostatic capacitance under load.

[0091] Each sensor unit includes conductive elastomers 12 and 22 and a pair of conductor wires 13. The pair of conductor wires 13 constitute one electrode (e.g., anode) of a static capacitor, and the conductive elastomers 12 and 22 constitute the other electrode (e.g., cathode) of the static capacitor. That is, the conductive member 31 within the pair of conductor wires 13 constitutes one electrode of the load sensor 1 (static capacitance type load sensor), the conductive elastomers 12 and 22 constitute the other electrode of the load sensor 1 (static capacitance type load sensor), and the dielectric 32 within the pair of conductor wires 13 corresponds to the dielectric of a specified static capacitance in the load sensor 1 (static capacitance type load sensor).

[0092] If a load is applied to each sensor unit in the Z-axis direction, the pair of conductor wires 13 will be wrapped into the conductive elastomers 12 and 22 due to the load. As a result, the contact area between the pair of conductor wires 13 and the conductive elastomers 12 and 22 changes, and the electrostatic capacitance between the pair of conductor wires 13 and the conductive elastomers 12 and 22 changes.

[0093] The ends of the X-axis negative side of a pair of conductor wires 13, the ends of the Y-axis negative side of cable 12a, and the ends of the Y-axis negative side of cable 22a are connected to the detection circuit provided for the load sensor 1.

[0094] like Figure 5 As shown, the cables 12a and 22a leading out from the three sets of conductive elastomers 12 and 22 are referred to as lines L11, L12, and L13, and the conductive components 31 within the pairs of conductors 13 in the three sets are referred to as lines L21, L22, and L23. The locations where the conductive elastomers 12 and 22 connected to line L11 intersect with lines L21, L22, and L23 are sensor units A11, A12, and A13, respectively; the locations where the conductive elastomers 12 and 22 connected to line L12 intersect with lines L21, L22, and L23 are sensor units A21, A22, and A23, respectively; and the locations where the conductive elastomers 12 and 22 connected to line L13 intersect with lines L21, L22, and L23 are sensor units A31, A32, and A33, respectively.

[0095] If a load is applied to sensor section A11, the contact area between the pair of conductor lines 13 and the conductive elastomers 12 and 22 increases. Therefore, the load applied to sensor section A11 can be calculated by detecting the electrostatic capacitance between line L11 and line L21. Similarly, for other sensor sections, the load applied to those other sensor sections can be calculated by detecting the electrostatic capacitance between the two intersecting lines of those other sensor sections.

[0096] Here, when conductor wires 13a and 13b, which are made of stranded wires, are used as electrodes constituting the sensor section as described above, if untwisting occurs in conductor wires 13a and 13b as in Comparative Example 1 below, the relationship between load and electrostatic capacitance will unexpectedly change.

[0097] Figure 6 (a) is a cross-sectional view of the periphery of conductor lines 13a and 13b in Comparative Example 1, viewed in the negative X-axis direction.

[0098] In Comparative Example 1, untwisting occurred in conductor wires 13a and 13b. Figure 3 The state of multiple wires 30 combined as shown in (a) and (b) is released. Such untwisting can occur, for example, when multiple loads are applied to the conductor wires 13a and 13b. If such untwisting occurs, it is as follows: Figure 6 As shown in (a), when a load is applied, the multiple wires 30 unwind and extend in the Y-axis direction. In this case, compared with the case where the stranding state of the conductor wires 13a and 13b is appropriate, even when the same load is applied, the contact area between the conductor wire 13a and the conductive elastomers 12 and 22 will increase, and the electrostatic capacitance will increase.

[0099] Figure 6 (b) is a diagram illustrating the change in electrostatic capacitance in Comparative Example 1.

[0100] Figure 6 The graph on the left of (b) is a graph showing the relationship between the load on a sensor section and the electrostatic capacitance of the sensor section when no untwisting occurs in the conductors 13a and 13b of the pair of conductors 13. In the case where no untwisting occurs in the conductors 13a and 13b, Figure 6 In the example shown in the graph on the left side of (b), the value of the static capacitance is also approximately 0 when the load value is 0.

[0101] Figure 6 The graph to the right of (b) is a graph showing the relationship between the load on a sensor section and the electrostatic capacitance of the sensor section in the case of untwisting in the conductors 13a and 13b of a pair of conductors 13. Figure 6The curve shown by the dashed line in the graph to the right of (b) is... Figure 6 The curve in the graph to the left of (b) is the same.

[0102] In this case, due to, as Figure 6 As shown in (a), untwisting occurs in conductor wires 13a and 13b, thus increasing the contact area between conductor wires 13a and 13b and conductive elastomers 12 and 22 compared to the case without untwisting. Therefore, in Figure 6 In the chart to the right of (b), with Figure 6 Compared to the graph on the left of (b), the electrostatic capacitance is shifted upwards. In this case, if the load is detected based on the detected electrostatic capacitance, the applied load will be detected as larger than the true value.

[0103] To this end, the inventors verified the twist p of the conductors 13a and 13b that makes it difficult for untwisting to occur in the conductors 13a and 13b.

[0104] The verification conditions are as follows. The outer diameter d (reference) of the wire 30 within a pair of conductor wires 13. Figure 3 (b) is set to any one of 0.055mm, 0.073mm, or 0.105mm. The number n of wires 30 contained in one conductor wire 13a or 13b is set to any one of 7, 11, or 15. The twist p of conductor wires 13a or 13b is (refer to...) Figure 3 (a) is set to any of 3mm, 5mm, 10mm, 15mm, or 20mm. 15 types of pairs of conductor wires 13 are made by combining the outer diameter d, the quantity n, and the twist pitch p.

[0105] A pair of conductor wires 13 were respectively placed on the load sensor 1. As a preliminary measurement, the electrostatic capacitance was measured when a load of 0.3 MPa was applied. Then, a load of 0.5 MPa was applied to the load sensor 1 10,000 times. After that, as a subsequent measurement, the electrostatic capacitance was measured when a load of 0.3 MPa was applied again.

[0106] Figure 7 (a) is a table showing the results of the inventors' verification of the twist p.

[0107] "○" indicates that the rate of increase is less than 10% in both the pre- and post-tests. "×" indicates that the rate of increase of electrostatic capacitance is greater than 10% in both the pre- and post-tests. If the rate of increase is greater than 10%, it can be determined that untwisting has occurred in conductor wires 13a and 13b. "-" indicates that it cannot be verified because the minimum twist pitch is insufficient.

[0108] The results of this verification show that, with d = 0.055 and n = 7, the rate of increase in electrostatic capacitance is greater than 10% when the twist pitch p is 5 mm or more. With d = 0.073 and n = 11, the rate of increase in electrostatic capacitance is greater than 10% when the twist pitch p is 10 mm or more. With d = 0.105 and n = 15, the rate of increase in electrostatic capacitance is greater than 10% when the twist pitch p is 20 mm.

[0109] Here, the inventors focus on the value of 12nd, which is the product of the outer diameter d of wire 30, the number n of wires 30, and 12. When the outer diameter d and the number n are three, if 12nd is calculated separately, then... Figure 7 As shown in Table (a), the values ​​are 4.6, 9.6, and 18.9. The inventors found that when comparing these 12nd values ​​with the twist p, the twist p is less than the value of 12nd, and the increase rate of electrostatic capacitance is suppressed to less than 10%.

[0110] That is, with d = 0.055 and n = 7, since the value of 12nd is 4.6, it is presumed that when the twist pitch p is 4.6 or less, the rate of increase in electrostatic capacitance is suppressed to less than 10%. This presumption is consistent with the above verification results. Similarly, with d = 0.073 and n = 11, since the value of 12nd is 9.6, it is presumed that when the twist pitch p is 9.6 or less, the rate of increase in electrostatic capacitance is suppressed to less than 10%. This presumption is also consistent with the above verification results. Similarly, with d = 0.105 and n = 15, since the value of 12nd is 18.9, it is presumed that when the twist pitch p is 18.9 or less, the rate of increase in electrostatic capacitance is suppressed to less than 10%. This presumption is also consistent with the above verification results.

[0111] Therefore, it can be seen that when the twist p of the multiple wires 30 satisfies the following condition (1), the rate of increase of electrostatic capacitance can be suppressed to less than 10%. The conductor wires 13a and 13b of Embodiment 1 are configured to satisfy the following condition (1).

[0112] p≤12nd…(1)

[0113] p: Twist pitch of multiple wires

[0114] n: The number of wires contained in the conductor wire

[0115] d: Outer diameter of the wire

[0116] Figure 7 (b) is a diagram illustrating the change in electrostatic capacitance in Implementation 1.

[0117] Figure 7 The chart on the left of (b) and Figure 6The same applies to the chart on the left of (b). Figure 7 The graph to the right of (b) is a graph showing the relationship between load and electrostatic capacitance after applying loads to the load sensor 1 of Embodiment 1 multiple times (e.g., 10,000 times). Figure 7 The curve shown by the dashed line in the chart to the right of (b) is also... Figure 7 The curve in the graph to the left of (b) is the same.

[0118] According to the load sensor 1 of embodiment 1, since the twist pitch p is set to satisfy the above formula (1), after multiple loads are applied, untwisting will not occur in the conductor wires 13a and 13b. Therefore, the contact area between the conductor wires 13a and 13b and the conductive elastomers 12 and 22 is similar to that in the case where no untwisting occurs ( Figure 7 Compared to the chart on the left of (b), there was almost no increase. Therefore, in Figure 7 In the graph to the right of (b), the difference between the curve in the case where no untwisting occurs (the curve shown by the dashed line) and the curve after multiple loads were applied in Embodiment 1 (the curve shown by the solid line) is significantly suppressed.

[0119] <Effects of Implementation Method 1>

[0120] The above-described implementation method 1 achieves the following effects.

[0121] A pair of conductor wires 13a and 13b are disposed between a substrate 21 and a conductive elastomer 12, and are formed by twisting multiple wires 30 together. The conductor wires 13a and 13b are formed by coating the surface of the linear conductive member 31 with a dielectric 32. Furthermore, the twist pitch p of the multiple wires 30 is configured to satisfy the above formula (1). Therefore, since untwisting of the wires 30 is suppressed, thus, as... Figure 7 As shown in the diagram on the right of (b), the characteristic change of electrostatic capacitance between the conductive elastomers 12, 22 and the conductive member 31 is suppressed. Therefore, the load can be appropriately detected using conductor wires 13a, 13b (stranded wires) formed by twisting multiple wires 30 together.

[0122] Multiple conductive elastomers 12 and 22 each have a strip-like shape that is elongated in the Y-axis direction perpendicular to the direction (X-axis direction) in which the conductor lines 13a and 13b extend, and multiple sets of a pair of conductor lines 13 are arranged in the Y-axis direction. Thus, the area (sensor section) used for detecting loads can be arranged in a matrix.

[0123] A conductive elastomer 12 is formed on the opposing surface 11a of the substrate 11, and a conductive elastomer 22 is disposed opposite to the conductive elastomer 12 on the opposing surface 21a of the substrate 21. Furthermore, a pair of conductor lines 13 (conductor lines 13a, 13b) are disposed between the conductive elastomer 12 and the conductive elastomer 22. Therefore, since the electrostatic capacitance between the conductive elastomers 12, 22 and the pair of conductor lines 13 (conductor lines 13a, 13b) can be set to be large, the sensitivity of the load sensor 1 can be improved.

[0124] A pair of conductor wires 13 (conductor wires 13a and 13b) are arranged in a wave shape in a plane parallel to the substrates 11 and 21 (in the XY plane). Therefore, even when the substrates 11 and 21 expand or contract in the plane parallel to them, the change in the bending state of the pair of conductor wires 13 (conductor wires 13a and 13b) can prevent breakage. Furthermore, compared to arranging the pair of conductor wires 13 (conductor wires 13a and 13b) in a straight line, the density of conductor wires per unit area is increased, thus improving the detection sensitivity of the load sensor 1.

[0125] <Implementation Method 2>

[0126] In the load sensor 1 of Embodiment 1 described above, the inventors further investigated ways to improve sensitivity and expand dynamic range. As a result, the inventors found that by narrowing the spacing between conductor wires 13a and 13b relative to the width of the sensor portion, thereby increasing the tilt angle of the wave shape of the pair of conductor wires 13, the sensitivity of the load sensor 1 was improved and the dynamic range was expanded. In Embodiment 2, as shown below, the widths of conductor wires 13a and 13b that resulted in good sensitivity and dynamic range were investigated, and a load sensor 1 with widths of conductor wires 13a and 13b set based on the investigation results was used. Furthermore, the other structures of Embodiment 2 are the same as those of Embodiment 1.

[0127] Figure 8 This is a diagram used to illustrate the spacing of conductor lines 13a and 13b and the width of the sensor section in Embodiment 2. Figure 8 This is a top view schematically showing the interior of load sensor 1 when viewed in the negative Z-axis direction. Figure 8 In, with Figure 5 Similarly, the nine sensor units A are arranged in a matrix.

[0128] exist Figure 8In the diagram, the width of one sensor unit A in the direction in which sensor units A are arranged (the X-axis and Y-axis directions) is d1, and the spacing between a pair of conductor lines 13 (the spacing between conductor lines 13a and 13b) in the direction in which the conductive elastic bodies 12 and 22 extend (the Y-axis direction) is d2. The angle of inclination between the wave shape of the pair of conductor lines 13 (conductor lines 13a and 13b) and the direction in which the pair of conductor lines 13 extend (the X-axis direction) is θ. The angle of inclination θ is the angle when the angle between the wave shape and the X-axis direction is at its maximum.

[0129] The inventors in Figure 8 In the load sensor 1 shown, the width d1 of the sensor section A is fixed at 12 mm, and the interval d2 of the conductor lines 13a and 13b is set to any one of 3 mm, 4 mm, 5 mm, 6 mm, or 7 mm. Five types of load sensors 1 are made corresponding to these five values ​​of interval d2. Each load sensor 1 is then constructed such that the pair of conductor lines 13 falls within the width d1 of the sensor section A arranged in the X-axis direction, and the waveform of the pair of conductor lines 13 has the maximum amplitude in the Y-axis direction. Then, the load is varied, and the electrostatic capacitance is measured.

[0130] Figure 9 It is a graph showing the results of the inventors' verification of the spacing d2 of conductor lines 13a and 13b.

[0131] exist Figure 9 This diagram shows the relationship between load and static capacitance from the point of contact between conductive elastomers 12 and 22 until the static capacitance saturates. In other words, it demonstrates a range within which load can be measured smoothly and appropriately while maintaining linearity in the measurement of static capacitance. This range is termed the dynamic range of load measurement. Figure 9 The diagram shows the range within which linearity is ensured amidst changes in electrostatic capacitance. Therefore, the maximum load within this range becomes the maximum load that can be properly detected (the maximum load of the dynamic range).

[0132] like Figure 9 As shown, it can be seen that as the interval d2 decreases, the value of the electrostatic capacitance corresponding to the load increases, and the sensitivity of the load sensor 1 increases. Furthermore, it can be seen that as the interval d2 decreases, the maximum load that can be appropriately detected increases, and the dynamic range of the load sensor 1 increases. Moreover, when the interval d2 is 3mm to 5mm, compared to the case where the interval d2 is 6mm to 7mm, the electrostatic capacitance corresponding to the load becomes larger, and the maximum detectable load becomes larger.

[0133] Based on the above results, the inventors determined that, preferably, when the width d1 of the sensor section A is 12 mm, the spacing d2 of the conductor lines 13a and 13b is 3 mm to 5 mm. Furthermore, based on this result, the inventors derived the following equation (2) as a conditional expression for the width d1 and the spacing d2.

[0134] d2≤d1 / 2…(2)

[0135] That is, if the width d1 and the interval d2 are set to satisfy the above equation (2), the sensitivity of the load sensor 1 is improved and the dynamic range of the load sensor 1 is expanded.

[0136] Figure 10 (a) and (b) are schematic top views of the interior of the load sensor 1 in Embodiment 2 and Comparative Example 2, respectively, when viewed in the negative Z-axis direction. Figure 10 In (a) and (b), for convenience, only a portion of the sensor unit A is shown.

[0137] like Figure 10 As shown in (a), in Embodiment 2, the width d1 of the sensor section A and the interval d2 of the conductor lines 13a and 13b are set such that the above equation (2) is satisfied (d2 ≤ d1 / 2). On the other hand, as Figure 10 As shown in (b), in Comparative Example 2, the width d1 and the interval d2 are set such that the above equation (2) is not satisfied (d2 > d1 / 2). Figure 10 As shown in embodiment 2 of (a), if the width d1 and the interval d2 are set, then with Figure 10 Compared with Comparative Example 2 (b), the tilt angle θ can be increased. This increases the change in electrostatic capacitance of sensor section A. Furthermore, since conductors 13a and 13b are subjected to load over a large contact area, they become embedded in conductive elastomers 12 and 22, and conductive elastomers 12 and 22 come into contact. This increases the load (maximum load of the dynamic range) when the load begins to be supported between conductive elastomers 12 and 22.

[0138] <Effects of Implementation Method 2>

[0139] The above-described implementation method 2 achieves the following effects.

[0140] When the sensor section A is constructed by crossing the conductive elastomers 12 and 22 and a pair of conductor wires 13 as described above, it is desirable to improve the sensitivity of the load sensor 1 and expand the dynamic range of the load sensor 1.

[0141] Therefore, the load sensor 1 of Embodiment 2 is configured as follows.

[0142] A load sensor 1, which has at least a plurality of sensor units A arranged in a first direction (X-axis direction) in the measurement area, includes: a first substrate 11 and a second substrate 21 arranged face to face; a plurality of conductive elastomers 12 disposed on the opposing surface of the first substrate 11 at positions corresponding to the plurality of sensor units A; and a pair of conductor lines 13 arranged between the second substrate 21 and the conductive elastomers 12, extending along the plurality of sensor units A and having a dielectric 32 around them. The pair of conductor lines 13 are arranged in a wave shape with amplitude in a second direction (Y-axis direction) perpendicular to the first direction (X-axis direction) in a plane parallel to the first substrate 11 and the second substrate 21, intersecting the plurality of conductive elastomers 12 at the positions of the plurality of sensor units A, and the interval between the two conductor lines 13a and 13b constituting the pair of conductor lines 13 is less than 1 / 2 of the width of the sensor unit A in the second direction.

[0143] like Figure 8 As shown, in the load sensor 1, multiple sensor units A are arranged in the X-axis direction (first direction) within the measurement area R. The conductive elastomer 12 is positioned on the opposing surface 11a of the substrate 11 (reference). Figure 1 The conductors are positioned at locations corresponding to the plurality of sensor sections A arranged in the X-axis direction, as shown in (a) and (b). A pair of conductor lines 13 are arranged between the substrate 21 and the conductive elastomer 12, extending along the plurality of sensor sections A arranged in the X-axis direction. The pair of conductor lines 13 are arranged in a wave shape with amplitude in the Y-axis direction (second direction) perpendicular to the X-axis direction (first direction) in a plane parallel to the substrates 11 and 21, and intersect with the plurality of conductive elastomers 12 at the locations of the plurality of sensor sections A arranged in the X-axis direction. Furthermore, the interval d2 between the two conductor lines 13a and 13b is set to be less than half the width d1 of the sensor section A.

[0144] If the interval d2 between the two conductor lines 13a and 13b constituting a pair of conductor lines 13 is set in this way, the pair of conductor lines 1 can be contained within the width d1 of the sensor section A, and the tilt angle θ of the waveform of the pair of conductor lines 13 can be made large. If the tilt angle θ of the waveform increases, then... Figure 10 As shown in (a), at the position of sensor section A, a pair of conductor wires 13 cross in an oblique direction relative to the conductive elastomers 12 and 22, and the contact length between the pair of conductor wires 13 and the conductive elastomers 12 and 22 is extended.

[0145] Therefore, since the change in electrostatic capacitance under applied load can be increased, the sensitivity of load sensor 1 can be improved. Furthermore, since the contact area between conductors 13a and 13b and conductive elastomers 12 and 22 is increased, the pressure applied by the load to the conductive elastomers 12 and 22 in contact with conductors 13a and 13b is suppressed. That is, the conductors 13a and 13b become more difficult to... Figure 4 As shown in (b), the conductive elastomers 12 and 22 are embedded, thus increasing the range of loads that occur until one conductive elastomer comes into contact with the other and its properties become saturated. This expands the dynamic range of detectable loads.

[0146] Multiple conductive elastomers 12 and 22 each have a strip-like shape that is long in the Y-axis direction (second direction), and multiple sets of a pair of conductor wires 13 are arranged in the Y-axis direction. Thus, the area (sensor section A) used for detecting load can be arranged in a matrix.

[0147] Furthermore, the load sensor 1 includes another conductive elastomer 22 disposed opposite to the conductive elastomer 12 on the opposing surface of the second substrate 21, and the pair of conductor lines 13 are disposed between the conductive elastomer 12 and the other conductive elastomer 22.

[0148] That is, the conductive elastomer 12 is disposed on the opposing surface 11a of the substrate 11, and the other conductive elastomers 22 are disposed on the opposing surface 21a of the substrate 21, so as to be opposite to the conductive elastomer 12. Furthermore, a pair of conductor wires 13 are disposed between the conductive elastomer 12 and the other conductive elastomers 22. Therefore, compared to the case where only one of the conductive elastomers 12 or 22 is disposed, the electrostatic capacitance between the conductive elastomers 12 / 22 and the pair of conductor wires 13 can be set to be large, thereby improving the sensitivity of the load sensor 1.

[0149] Conductor wires 13a and 13b are as referenced. Figure 3 As explained in (a), the conductors 13a and 13b are formed by twisting together multiple wires 30, and each wire 30 is formed by coating the surface of a linear conductive member 31 with a dielectric 32. Thus, if the conductors 13a and 13b are stranded wires formed by twisting together multiple wires 30, the bending resistance of the conductors 13a and 13b can be improved. Therefore, as... Figure 10 As shown in (a), even if a pair of conductor wires 13 are configured in a wave shape, damage to the pair of conductor wires 13 can be prevented.

[0150] <Example of Change>

[0151] The structure of the load sensor 1 can be modified in various ways, in addition to the structure shown in the above embodiments.

[0152] For example, in embodiments 1 and 2 described above, the number n of wires 30 contained in conductor wire 13a or conductor wire 13b is as follows: Figure 7 As shown in table (a), 7, 11, and 15 wires can be cited, but the number n of wires 30 is not limited to this.

[0153] Furthermore, in the above embodiment 1, the load sensor 1 has three sets of a pair of conductor wires 13, but having at least one set of a pair of conductor wires 13 is sufficient. For example, the load sensor 1 may have only one set of a pair of conductor wires 13.

[0154] Furthermore, in embodiments 1 and 2 described above, the load sensor 1 includes three sets of conductive elastomers 12 and 22 arranged vertically opposite each other, but it is sufficient to include at least one set of conductive elastomers 12 and 22. For example, the load sensor 1 may include only one set of conductive elastomers 12 and 22.

[0155] Furthermore, in embodiments 1 and 2 described above, the conductive elastomer 22 on the substrate 21 side may be omitted. In this case, a pair of conductor wires 13 are sandwiched between the conductive elastomer 12 on the substrate 11 side and the opposing surface 21a of the substrate 21. Corresponding to the load, the pair of conductor wires 13 are embedded in the conductive elastomer 12, and the electrostatic capacitance in each sensor unit changes.

[0156] Furthermore, in Embodiment 1 described above, the pair of conductor lines 13 are configured such that conductor lines 13a and 13b arranged in the Y-axis direction are connected at their ends in the X-axis direction. However, a single conductor line may be used instead of a pair of conductor lines 13, or three or more conductor lines may be used. Additionally, in Embodiment 1 described above, the shape of the pair of conductor lines 13 may not be wavy; it may be a straight line. When a single conductor line is used instead of a pair of conductor lines 13, the shape of that conductor line may also be a straight line.

[0157] Furthermore, in the above-described embodiment 2, the conductors 13a and 13b of a pair of conductors 13 may not be made of stranded wire, but may be made of a single wire 30.

[0158] Furthermore, in embodiments 1 and 2 described above, conductive elastomers 12 and 22 are formed on the opposing surfaces 11a and 21a respectively using a given printing method. However, this is not a limitation; conductive elastomers 12 and 22 may also be provided on the opposing surfaces 11a and 21a respectively using an adhesive or the like.

[0159] Furthermore, in the above embodiments 1 and 2, conductor wires 13a and 13b are formed by twisting wires 30 composed of conductive member 31 and dielectric 32, but it is not limited to this. Conductor wires 13a and 13b can also be formed by covering the surface of the stranded wires formed by twisting conductive member 31 with dielectric.

[0160] Furthermore, in embodiments 1 and 2 described above, the load sensor 1 is rectangular in shape, but it is not limited to this and can also be other shapes. For example, the load sensor 1 can be circular, elliptical, sector-shaped, or it can be a shape in which the center of a sector is cut into a circle. The shape of the load sensor 1 can be freely set.

[0161] The following is for reference Figures 11-13 (b) will be used to illustrate the manufacturing steps of load sensor 1 in the case where the center of the sector is cut into a circular shape.

[0162] Figure 11 This is a flowchart illustrating the steps of the manufacturing method for load sensor 1. Figure 12 (a)~ Figure 13 (b) is a schematic diagram showing the manufacturing process of load sensor 1. Figure 12 (a)~ Figure 13 The substrates 11 and 21, the conductive elastomers 12 and 22, and the pair of conductor wires 13 shown in (b) are the same as in the above embodiment.

[0163] In the following manufacturing processes, such as Figure 12 As shown in (a), a parent substrate 10 with multiple conductive elastomers 12 arranged in a specific configuration is prepared in advance. A region with a shape matching the shape of the load sensor 1 is cut from this parent substrate 10, and this cut region is used as the substrate of the load sensor 1. When using the upper and lower substrates 11 and 21 in the load sensor 1, the two substrates 11 and 21 are respectively cut from the parent substrate 10 so that the shape viewed from above when they are stacked vertically becomes the shape of the load sensor 1. Furthermore, as... Figure 13 As shown in (b), a plurality of pairs of conductor wires 13 are formed to match the shape of the cut substrates 11, 21. Then, the plurality of pairs of conductor wires 13 formed are arranged between the upper and lower substrates 11, 21 to form a load sensor 1.

[0164] More in detail, Figure 11 In step S11, the substrate 11 on the lower surface side and the conductive elastomer 12 are cut from the parent substrate 10 to match the measurement area R (the area of ​​the final shape of the load sensor 1), and the substrate 21 on the upper surface side and the conductive elastomer 22 are cut from the parent substrate 10 to match the measurement area R.

[0165] Specifically, such as Figure 12 As shown in (a), the substrate 10 has a square shape, and on the surface of the substrate 10 on the positive side of the Z-axis, a plurality of conductive elastomers 12 are arranged in the X-axis direction and form extending in the Y-axis direction. Figure 12 The area corresponding to the measurement area R is cut out from the mother substrate 10 shown in (a). Thus, as... Figure 12 The substrate 11 and the conductive elastomer 12 are formed as shown in (b) to correspond to the shape of the measurement area R. For convenience, in Figure 12 In (b), the conductive elastomer 12 is shown as a rectangle when viewed from above, but in reality, the ends of each conductive elastomer 12 on the positive and negative sides of the Y-axis extend in the Y-axis direction to the boundary of the substrate 11.

[0166] Furthermore, in the above process, multiple conductive elastomers 12 are pre-positioned on the parent substrate 10, but it is also possible not to position the conductive elastomers 12 on the parent substrate 10. In this case, after forming the substrate 11 by cutting out the area corresponding to the measurement area R from the parent substrate 10, as shown... Figure 12 As in (b), a plurality of rectangular conductive elastomers 12 are disposed on the upper surface of the substrate 11.

[0167] Thus, as Figure 12 As shown in (b), the substrate 11 and the conductive elastomer 12 are formed to correspond to the measurement region R. Similarly, the substrate 21 and the conductive elastomer 22 are also formed to correspond to the measurement region R.

[0168] Next, in step S12, as Figure 13 As shown in (a), a pair of conductor lines 13 are formed in conjunction with the measurement area R. Specifically, a plurality of pairs of conductor lines 13 are arranged extending in the X-axis direction such that the folded-back portion on the positive side of the X-axis is located within the measurement area R. Figure 13 In (a), the folded portion of a pair of conductor lines 13 in the three groups set to the negative side of the Y-axis is located further to the negative side of the X-axis than the other pair of conductor lines 13, so as to match the circular hole inside the measurement area R.

[0169] Next, in step S13, as Figure 13 As shown in (b), a substrate 11 with conductive elastomer 12, a substrate 21 with conductive elastomer 22, and a pair of conductor wires 13 are assembled. Figure 13 (b) is a top view schematically showing the interior of the load sensor 1 when viewed in the negative Z-axis direction. By overlapping the two substrates 11 and 21, and aligning the two conductive elastomers 12 and 22 in a mutually opposing state, a pair of conductor wires 13 are sandwiched between the two conductive elastomers 12 and 22. Thus, the assembly of the load sensor 1 is completed.

[0170] In the above manufacturing process, since the area matching the measuring area R (the area of ​​the final shape of the load sensor 1) is cut from the parent substrate 10, and the substrates 11 and 21 and the conductive elastomers 12 and 22 are formed in one step, the assembly time of the load sensor 1 can be reduced, and the load sensor 1 can be manufactured easily. Regarding this effect, see [reference needed]. Figure 14The following comparative example 3 will be used for illustration.

[0171] Figure 14 This is a top view schematically illustrating the manufacturing method of the load sensor 100 involved in Comparative Example 3.

[0172] In Comparative Example 3, rectangular sensor assemblies 110 and 120 are disposed on a substrate 130 forming the shape of the load sensor 100. Sensor assembly 110 includes: a substrate 111; three conductive elastomers 112 extending in the Y-axis direction; and a pair of conductor wires 113 extending in two sets in the X-axis direction. Sensor assembly 120 includes: a substrate 121; a conductive elastomer 122; and a pair of conductor wires 123 extending in the X-axis direction.

[0173] Substrate 130 and Figure 12 Similarly, in (b) the substrate 11 has a fan-shaped center cut into a circular shape. Three sensor assemblies 110 and one sensor assembly 120 are provided on the substrate 130. A substrate having the conductive elastomers 111, 121 and 112, 122 opposite to the conductive elastomers 111, 121 and 122, and another substrate having the conductive elastomer opposite to the conductive elastomer are superimposed on the upper surface of the substrate 130. Thus, the load sensor 100 of Comparative Example 3 is completed.

[0174] In Comparative Example 3, because multiple sensor assemblies 110 and 120 need to be individually manufactured and then arranged on the substrate 130 in order to effectively lay out the substrate 130, the assembly time increases. Furthermore, Figure 14 In the load sensor 100, since the rectangular sensor components 110 and 120 are arranged on the substrate 130, the area (insensitive zone) in the area (measuring area) of the substrate 130 where the sensor components 110 and 120 are not arranged becomes larger.

[0175] In contrast, according to Figure 12 (a)~ Figure 13 The load sensor 1 shown in (b) significantly reduces assembly time compared to Comparative Example 3 because, during the manufacturing of the load sensor 1, a region matching the measurement area R (the region of the final shape of the load sensor 1) is cut from the parent substrate 10, and the substrates 11 and 21 and the conductive elastomers 12 and 22 are formed in one step. Furthermore, since it is not necessary to arrange the sensor assemblies 110 and 120 in a given layout on the substrate 130 as in Comparative Example 3, the manufacturing process of the load sensor 1 can be easily automated.

[0176] In addition, the length and fold-back position of the pair of conductor wires 13 can be freely set according to the shape of the substrates 11 and 21 by using the clamp 200 shown below.

[0177] Figure 15 This is a top view showing the structure of the clamp 200 used to form a pair of conductor wires 13. Figure 15 In the middle, for convenience, and Figure 13 Similarly, in (a) and (b), the direction in which a pair of conductor lines 13 extend is used as the X-axis direction to label the X, Y, and Z axes.

[0178] In the fixture 200, a plurality of pairs of slots 210 are arranged in the Y-axis direction, forming a bend in the Y-axis direction and extending in the X-axis direction. Figure 15 In the fixture 200, 16 pairs of slots 210 are arranged in the Y-axis direction. Each pair of slots 210 consists of two slots 211 extending in the X-axis direction with the same zigzag period. The ends of the pairs of slots 211 on the positive X-axis side are connected by fold-back slots 220. Furthermore, the pairs of slots 211 are connected at given intervals by multiple fold-back slots 220 from the ends on the negative X-axis side to the ends on the positive X-axis side. The slots 211 and the fold-back slots 220 are recesses one level lower than the upper surface 201 (the surface on the positive Z-axis side) of the fixture 200. In addition, in the fixture 200, pins 231 and 232 are formed corresponding to the two slots 211 on the negative X-axis side of the pairs of slots 210, respectively. The pins 231 and 232 are used when forming a pair of conductor wires 13.

[0179] Figure 16 (a) to (d) are top views illustrating the steps of forming a pair of conductor wires 13 using the clamp 200.

[0180] When using the clamp 200 to form a pair of conductor wires 13, the conductor wires 13c from the coil will be passed through the nozzle. Then, as... Figure 16 As shown in (a), the end of the conductor wire 13c extending from the front end of the nozzle is hooked to and fixed by the pin 231 disposed on the outside of the slot 211. In this state, as Figure 16 As shown in (b), the tip of the nozzle is pushed into the position of the groove 211 and moved along the groove 211 in the positive direction of the X-axis from the end on the negative X-axis side of the groove 211. As a result, the conductor wire 13c is led out from the nozzle and disposed inside the groove 211.

[0181] Thus, if the nozzle moves to the fold-back groove 220, which becomes the fold-back position of conductor wire 13c, it is as follows: Figure 16 As shown in (c), the tip of the nozzle is moved through the fold-back groove 220 to the adjacent groove 211. This forms a fold-back portion of a pair of conductor wires 13. The fold-back position is determined according to the shape of the load sensor 1 and the measurement area R.

[0182] Next, as Figure 16As shown in (d), the tip of the nozzle is moved along the adjacent slot 211 in the negative X-axis direction, and the conductor wire 13c is positioned along the adjacent slot 211. The nozzle is moved further from the end of the adjacent slot 211 on the negative X-axis side to a position at a given distance in the negative X-axis direction, and the conductor wire 13c near the tip of the nozzle is hooked onto the pin 232 positioned on the outside of the slot 211 and secured. Then, the end of the conductor wire 13c folded back on the negative X-axis side is cut off at the same position in the X-axis direction, completing a pair of conductor wires 13.

[0183] By repeating this operation sequentially on each pair of slots 210, multiple pairs of conductor wires 13 in one load sensor 1 are formed. At this time, the fold-back position of the conductor wires 13c is set at a position corresponding to the length of each conductor wire 13c. This is how they are formed. Figure 13 As shown in (a) and (b), there are multiple pairs of conductor lines 13 with different lengths and fold-back positions.

[0184] Thus, by using the clamp 200 and moving the tip of the nozzle along a pair of slots 210 and a foldback slot 220 of the clamp 200, a pair of conductor wires 13 of various lengths can be easily formed. Therefore, by controlling the movement mechanism of the nozzle in a movement pattern corresponding to the length of the pair of conductor wires 13, a pair of conductor wires 13 of various lengths can be automatically formed.

[0185] Furthermore, the pair of conductor wires 13c used in the above manufacturing process can be conductor wires with a stranded structure as described in Embodiment 1, or they can be conductor wires composed of single wires. In addition, the number of the pair of slots 210 disposed in the fixture 200 is not limited to... Figure 15 As shown, other quantities are also possible. Furthermore, the shapes of the substrates 11 and 21 are not limited to... Figure 12 The shapes shown in (a) and (b) can be freely changed according to the shape of the device on which the load sensor 1 is installed.

[0186] Figure 17 This is a schematic diagram showing the internal structure of the load sensor 1 when it is positioned on the toilet seat. Additionally, in Figure 17 The image shows the inner portion of the load sensor 1 cut into a rectangle along the opening H10 of the toilet seat, retaining the rectangular shape for convenience. However, in reality, the outer portion of the load sensor 1 is cut into an elliptical shape along the shape of the toilet seat surface (a roughly enlarged shape based on the shapes of notches 311 and 321).

[0187] Figure 17The load sensor 1 shown includes two sensor assemblies 310 and two sensor assemblies 320. The two sensor assemblies 310 are arranged on the negative side of the Y-axis in the X-axis direction, and the two sensor assemblies 320 are arranged on the positive side of the Y-axis in the X-axis direction. The two sensor assemblies 310 have the same shape and structure and are arranged opposite to each other. Similarly, the two sensor assemblies 320 have the same shape and structure and are arranged opposite to each other.

[0188] The centers of the four sensor assemblies 310 and 320 are positioned at the opening H10 of the toilet seat. A notch 311 is formed on the center side of the sensor assembly 310 at a position corresponding to the opening H10 of the toilet seat, and a notch 321 is formed on the center side of the sensor assembly 320 at a position corresponding to the opening H10 of the toilet seat.

[0189] Multiple conductive elastomers 12 and 22 extending in the Y-axis direction are respectively disposed on the substrates 11 and 21 of the sensor assembly 310. By forming a notch 311, the substrates 11 and 21 and the conductive elastomers 12 and 22 on the central side are cut off. A pair of conductor lines 13 of the multiple components of the sensor assembly 310 are configured with folded-back portions positioned outside the notch 311.

[0190] Similarly, multiple conductive elastomers 12 and 22 extending in the Y-axis direction are respectively disposed on the substrates 11 and 21 of the sensor assembly 320. By forming the notch 321, the substrates 11 and 21 and the conductive elastomers 12 and 22 on the central side are cut off. A pair of conductor lines 13 of the multiple components of the sensor assembly 320 are configured with folded-back portions positioned outside the notch 321.

[0191] according to Figure 17 The structure involves forming notches 311 and 321 in the square-shaped substrates 11 and 21 on which conductive elastomers 12 and 22 are disposed, and forming a pair of conductor wires 13 using the aforementioned clamp 200 corresponding to the shape of the notches 311 and 321. Thus, by assembling only the substrates 11 and 21, the conductive elastomers 12 and 22, and the pair of conductor wires 13, the load sensor 1 (sensor assembly 310, 320) can be constructed. Therefore, the assembly time of the load sensor 1 can be reduced, and the assembly of the load sensor 1 can be easily automated. Furthermore, since the notches 311 and 321 are formed corresponding to the shape of the opening H10 of the toilet seat, the folding position of each pair of conductor wires 13 can be adjusted, thereby reducing the area where the sensor section is not disposed (the insensitive zone). Therefore, the load distribution of a person sitting on the toilet seat can be accurately measured.

[0192] As described above, the method for manufacturing a load sensor according to this modified example includes the following steps: cutting out a region corresponding to the shape of the load sensor from a parent substrate on which a conductive elastomer is formed on the surface of a substrate to form the substrate and the conductive elastomer used in the load sensor; and placing a conductor wire coated with a dielectric onto the conductive elastomer of the cut substrate. According to this manufacturing method, as described above, assembly time can be reduced for load sensors with free shapes, and the load sensor can be manufactured easily. Furthermore, according to this manufacturing method, areas where the conductive elastomer and conductor wire are not disposed (insensitive zones) can be suppressed, and the detection accuracy of the load sensor can be improved.

[0193] Furthermore, the manufacturing method of the load sensor involved in this modified example is as described above, wherein the upper substrate and conductive elastomer, and the lower substrate and conductive elastomer are cut out from the parent substrate, and the dielectric-coated conductor wires are arranged between the cut conductive elastomers. This improves the detection sensitivity of the load sensor.

[0194] <Reference Example 1>

[0195] In the structure of the above-described embodiment 1, as follows: Figure 2 As shown in (b), the conductive elastomers 12 and 22 are arranged face to face. However, in such a structure, sometimes a misalignment occurs in the position where the conductive elastomer 12 is formed on the substrate 11, or in the position where the conductive elastomer 12 is arranged relative to the conductive elastomer 22. To address this, adjacent conductive elastomers 12 are arranged with a gap so that even if a misalignment occurs within the conductive elastomers 12, adjacent conductive elastomers 12 do not conduct to each other.

[0196] However, if the gap of the conductive elastomer 12 is left open, the area where the pressure-sensitive element cannot detect the load will become larger, i.e., the insensitive zone will become larger.

[0197] Therefore, in Reference Example 1, a load sensor 1 is constructed to avoid unexpected conduction and suppress insensitive bands.

[0198] refer to Figure 18 (a)~ Figure 21 To illustrate the general structure of the load sensor 1 involved in Reference Example 1.

[0199] Figure 18 (a) is a perspective view schematically showing the substrate 11 and three conductive elastomers 12 disposed on the opposing surface 11a (the surface on the positive side of the Z-axis) of the substrate 11.

[0200] The substrate 11 is an elastic, insulating component having a flat plate shape parallel to the XY plane. The substrate 11 is made of a non-conductive resin material or a non-conductive rubber material. The resin material used in the substrate 11 is, for example, at least one resin material selected from the group comprising styrene-based resins, silicone-based resins (e.g., polydimethylpolysiloxane (PDMS)), acrylic resins, rotaxane-based resins, and urethane-based resins. The rubber material used in the substrate 11 is, for example, at least one rubber material selected from the group comprising silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber, and natural rubber.

[0201] A conductive elastomer 12 is formed on the opposing surface 11a (the surface on the positive Z-axis side) of the substrate 11. Figure 18 In (a), three conductive elastomers 12 are formed on the opposing surface 11a of the substrate 11. Each conductive elastomer 12 is an elastic, conductive component. Each conductive elastomer 12 has a long, strip-like shape in the Y-axis direction and is arranged at a given interval in the X-axis direction. A cable 12a, electrically connected to the conductive elastomer 12, is provided at the end of each conductive elastomer 12 on the negative Y-axis side.

[0202] The conductive elastomer 12 is formed on the opposing surface 11a of the substrate 11 using printing methods such as screen printing, gravure printing, flexographic printing, offset printing, and gravure-offset printing. Through these printing methods, the conductive elastomer 12 can be formed on the opposing surface 11a of the substrate 11 with a thickness of 0.001 mm to 0.5 mm.

[0203] The conductive elastomer 12 is composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein.

[0204] The resin material used in the conductive elastomer 12 is the same as the resin material used in the substrate 11 described above, and is, for example, at least one resin material selected from the group including styrene-based resins, silicone-based resins (polydimethylpolysiloxane (e.g., PDMS), acrylic resins, rotaxane-based resins, and urethane-based resins. The rubber material used in the conductive elastomer 12 is the same as the rubber material used in the substrate 11 described above, and is, for example, at least one rubber material selected from the group including silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber, and natural rubber.

[0205] The conductive filler used in the conductive elastomer 12 is selected from at least one material from the group consisting of metallic materials such as Au (gold), Ag (silver), Cu (copper), C (carbon), ZnO (zinc oxide), In2O3 (indium oxide (III)) and SnO2 (tin oxide (IV)), conductive polymer materials such as PEDOT:PSS (i.e., a composite containing poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS), metal-coated organic fibers, conductive fibers such as metal wires (fiber state).

[0206] Figure 18 (b) is a schematic representation of a container placed on Figure 18 A three-dimensional view of the structure of (a) consisting of three copper-coated wires 15 and twelve wires 14.

[0207] One coated copper wire 15 is bent at its end on the positive X-axis side. That is, the coated copper wire 15 has a shape where a pair of coated copper wires are connected at their ends on the positive X-axis side. The coated copper wires 15 are arranged overlappingly. Figure 18 The upper surface of the three conductive elastomers 12 is shown in (a). Here, three copper-coated wires 15 are overlapped on the upper surface of the three conductive elastomers 12.

[0208] Each coated copper wire 15 consists of a conductive wire and a dielectric coating on the surface of the wire. Three coated copper wires 15 are arranged to intersect with conductive elastomers 12, spaced at a given interval along the long side (Y-axis direction) of the conductive elastomers 12. Each coated copper wire 15 is arranged along the X-axis direction, spanning three conductive elastomers 12. The structure of the coated copper wires 15 will be discussed later. Figure 20 Let's explain using (a) and (b).

[0209] In such Figure 18 After arranging the three copper-coated wires 15 as in (b), each copper-coated wire 15 is mounted on the substrate 11 using a wire 14, allowing it to move along its long side (X-axis direction). Figure 18 In the example shown in (b), 12 wires 14 connect the coated copper wire 15 to the substrate 11 at locations other than where the conductive elastomer 12 overlaps with the coated copper wire 15. The wires 14 are made of chemical fibers, natural fibers, or a mixture of these fibers.

[0210] Figure 19 (a) is a perspective view schematically showing the substrate 21 overlapping on the upper side of the substrate 11 and the three conductive elastomers 22 disposed on the opposing surface 21a (the surface on the negative side of the Z-axis) of the substrate 21.

[0211] Substrate 21 has the same size and shape as substrate 11 and is made of the same material as substrate 11. Conductive elastomer 22 is formed on the opposing surface 21a (the negative Z-axis side) of substrate 21, opposite to conductive elastomer 12, and is made of the same material as conductive elastomer 12. Conductive elastomer 22, like conductive elastomer 12, has a long, strip-like shape in the Y-axis direction and is formed by arranging them at given intervals in the X-axis direction. Conductive elastomer 22, like conductive elastomer 12, is formed on the negative Z-axis side of substrate 21 using a given printing method. Cables 22a electrically connected to conductive elastomer 22 are provided at the negative Y-axis end of each conductive elastomer 22.

[0212] The length (width in the long side direction) of the conductive elastomer 22 in the Y-axis direction is the same as the length (width in the long side direction) of the conductive elastomer 12 in the Y-axis direction. On the other hand, the length (width in the short side direction) of the conductive elastomer 22 in the X-axis direction can be smaller than the length (width in the short side direction) of the conductive elastomer 12 in the X-axis direction. The effects resulting from the difference in the width in the short side direction of the conductive elastomer 22 and the conductive elastomer 12 will be discussed later. Figure 23 (a)~ Figure 25 Let’s explain using (b).

[0213] Figure 19 (b) is a schematic representation of... Figure 18 (b) Construct settings Figure 19 A three-dimensional diagram of the state of the construct of (a).

[0214] from Figure 18 The structure shown in (b) is positioned above (positive Z-axis side) the top of it. Figure 19 The structure shown in (a) is as follows. In this configuration, substrate 11 and substrate 21 are arranged such that opposing surfaces 11a and 21a face each other, and the center positions of the conductive elastomer 12 and 22 in the X-axis direction overlap, as do the ends of the conductive elastomer 12 and 22 in the Y-axis direction. Furthermore, substrate 11 and substrate 21 are fixed by connecting the outer periphery of substrate 21 to the outer periphery of substrate 11 with a silicone rubber adhesive. Thus, the three copper-coated wires 15 are sandwiched between the three conductive elastomers 12 and 22.

[0215] exist Figure 19 In (b), for convenience, the load detection unit 1a, which is sandwiched between substrates 11 and 21, is shown in dashed lines. The load detection unit 1a includes multiple conductive elastomers 12, multiple conductive elastomers 22, and multiple coated copper wires 15. Thus, as... Figure 19 The load sensor 1 is completed as shown in (b).

[0216] Figure 20 (a) and (b) are schematic cross-sectional views of the periphery of the copper-coated wire 15 when viewed in the negative X-axis direction. Figure 20 (a) indicates the state without load applied. Figure 20 (b) indicates the state under which a load is applied.

[0217] like Figure 20 As shown in (a), the coated copper wire 15 is composed of a copper wire 15a and a dielectric 15b covering the copper wire 15a. The copper wire 15a is made of copper, and its diameter is, for example, about 60 μm. The dielectric 15b is disposed between the conductive elastomer 12 and the copper wire 15a, and between the conductive elastomer 22 and the copper wire 15a.

[0218] The dielectric 15b has electrical insulating properties and is made of, for example, resin materials, ceramic materials, metal oxide materials, etc. The dielectric 15b may be at least one resin material selected from the group including polypropylene resin, polyester resin (e.g., polyethylene terephthalate resin), polyimide resin, polyphenylene sulfide resin, polyvinyl alcohol formaldehyde resin, polyurethane resin, polyamide-imide resin, polyamide resin, etc., or at least one metal oxide material selected from the group including Al2O3 and Ta2O5, etc.

[0219] In the Figure 20 When a load is applied to the region shown in (a), the force applied between the conductive elastomer 12 and the coated copper wire 15, and the force applied between the conductive elastomer 22 and the coated copper wire 15, are approximately zero. If from this state onwards... Figure 20 When a load is applied upward to the lower surface of substrate 11 and downward to the upper surface of substrate 21 as shown in (b), the conductive elastomers 12 and 22 will deform due to the copper wire 15. Furthermore, even if the lower surface of substrate 11 or the upper surface of substrate 21 is placed on a stationary object and a load is applied only to the other substrate, a similar load will be applied from the stationary object side due to the reaction.

[0220] If so Figure 20 As shown in (b), when a load is applied, the coated copper wire 15 moves closer to the conductive elastomers 12 and 22, thereby increasing the contact area between the coated copper wire 15 and the conductive elastomers 12 and 22, which are encased in the conductive elastomers 12 and 22. This causes changes in the electrostatic capacitance between the copper wire 15a and the conductive elastomer 12, and between the copper wire 15a and the conductive elastomer 22. By detecting the electrostatic capacitance in this region, the load applied to this region can be calculated.

[0221] Figure 21This is a top view schematically showing the interior of load sensor 1 when viewed in the negative Z-axis direction. Figure 21 For convenience, the illustration of thread 14 is omitted.

[0222] like Figure 21 As shown, sensor sections A11, A12, A13, A21, A22, A23, A31, A32, and A33 are formed at the locations where the conductive elastomers 12 and 22 intersect with the coated copper wire 15, and these sections change in capacitance according to the load. Each sensor section includes the conductive elastomers 12 and 22 and the coated copper wire 15. The coated copper wire 15 constitutes one electrode of the electrostatic capacitance (e.g., an anode), and the conductive elastomers 12 and 22 constitute the other electrode of the electrostatic capacitance (e.g., a cathode).

[0223] That is, the copper wire 15a with copper wire 15 coating constitutes one electrode of the load sensor 1 (capacitive load sensor), the conductive elastomers 12 and 22 constitute the other electrode of the load sensor 1 (capacitive load sensor), and the dielectric 15b with copper wire 15 coating corresponds to the dielectric of the specified electrostatic capacitance in the load sensor 1 (capacitive load sensor).

[0224] If a load is applied to each sensor unit in the Z-axis direction, the coated copper wire 15 will be wrapped into the conductive elastomers 12 and 22 due to the load. As a result, the contact area between the coated copper wire 15 and the conductive elastomers 12 and 22 changes, and the electrostatic capacitance between the coated copper wire 15 and the conductive elastomers 12 and 22 changes.

[0225] The X-axis negative end of the copper-coated wire 15, the Y-axis negative end of the cable 12a, and the Y-axis negative end of the cable 22a are connected to the detection circuit provided for the load sensor 1.

[0226] like Figure 21 As shown, the cables 12a and 22a leading out from the three sets of conductive elastomers 12 and 22 are referred to as lines L11, L12, and L13, and the three copper wires 15a within the coated copper wires 15 are referred to as lines L21, L22, and L23. The locations where the conductive elastomers 12 and 22 connected to line L11 intersect with lines L21, L22, and L23 are sensor units A11, A12, and A13, respectively; the locations where the conductive elastomers 12 and 22 connected to line L12 intersect with lines L21, L22, and L23 are sensor units A21, A22, and A23, respectively; and the locations where the conductive elastomers 12 and 22 connected to line L13 intersect with lines L21, L22, and L23 are sensor units A31, A32, and A33, respectively.

[0227] If a load is applied to sensor section A11, the contact area between the coated copper wire 15 and the conductive elastomers 12 and 22 in sensor section A11 increases. Therefore, the load applied to sensor section A11 can be calculated by detecting the electrostatic capacitance between line L11 and line L21. Similarly, in other sensor sections, the load applied to that other sensor section can also be calculated by detecting the electrostatic capacitance between two intersecting lines in that other sensor section.

[0228] Figure 22 This is a top view schematically showing the specific structure of load sensor 1. Figure 22 For convenience, the load detection section 1a located inside the load sensor 1 is shown in solid line.

[0229] Figure 22 The load sensor 1 shown is Figure 18 (a)~ Figure 21 The load sensor 1 shown includes 16 conductive elastomers 12, 16 conductive elastomers 22, and 16 copper-coated wires 15. In this case, the 16 conductive elastomers 12 are arranged on a substrate 11, and the 16 conductive elastomers 22 are arranged on a substrate 21. The substrates 11 and 21 are then connected such that the conductive elastomers 12 and 22 face each other.

[0230] In addition, Figure 22 In the load sensor 1 shown, the copper-coated wire 15 is periodically bent. Figure 22 In this configuration, the periodically bent coated copper wire 15 is positioned on the upper side of the conductive elastomer 12, and... Figure 18 Similarly, in case (b), the copper wire 14 is connected to the substrate 11. Thus, by periodically bending the copper wire 15, even if the substrates 11 and 21 expand or contract, damage to the copper wire 15 can be avoided by changing the bending state of the copper wire 15. Furthermore, compared to arranging the copper wire 15 in a straight line, the higher density of copper wire 15a per unit area improves the detection sensitivity of the load sensor 1.

[0231] Next, the effect produced by the difference in the width of the short side (X-axis direction) of the conductive elastomer 12 and the width of the short side (X-axis direction) of the conductive elastomer 22 will be explained.

[0232] Figure 23 (a) and (b) are schematic diagrams of the structure of Comparative Example 1, in which the width of the short side of the conductive elastomer 12 is equal to the width of the short side of the conductive elastomer 22. Figure 23 (a) and (b) are cross-sectional views taken along the positive Y-axis at the location of the copper-coated wire 15, cut with a plane parallel to the XZ plane. Additionally, in Figure 23 In (a) and (b), for convenience, the copper-coated wire 15 is shown in a state where it extends in a straight line in the X-axis direction.

[0233] like Figure 23 As shown in (a), in Comparative Example 1, the width of the conductive elastomer 12 formed on the substrate 11 in the short side direction (X-axis direction) and the width of the conductive elastomer 22 formed on the substrate 21 in the short side direction (X-axis direction) are both set to d1. Furthermore, the spacing between the two conductive elastomers 12 and the spacing between the two conductive elastomers 22 are both set to dg1.

[0234] In Comparative Example 1, for example, Figure 23 As shown in (b), if the substrate 21 is disposed with a deviation of dg1 in the positive X-axis direction, the conductive elastomer 22 formed on the substrate 21 also moves a distance dg1 in the positive X-axis direction. Therefore, as Figure 23 As shown by the dashed line in (b), the positive X-axis end of the conductive elastomer 22 and the negative X-axis end of the conductive elastomer 12 overlap.

[0235] Thus, in Comparative Example 1, if a positional deviation from dg1 occurs in the X-axis direction during the installation of substrates 11 and 21, the conductive elastomers 12 and 22 of adjacent sensor units will become conductive. Similarly, if a positional deviation from dg1 occurs in the X-axis direction during the formation of conductive elastomers 12 and 22, the conductive elastomers 12 and 22 of adjacent sensor units will also become conductive. In this case, it is no longer possible to individually and appropriately detect the electrostatic capacitance based on the two adjacent sensor units.

[0236] Figure 24 (a) and (b) are schematic diagrams showing the structure of Comparative Example 2, in which the width of the conductive elastomers 12 and 22 in the short side direction is shortened relative to Comparative Example 1.

[0237] like Figure 24 As shown in (a), in Comparative Example 2, the width of the short side (X-axis direction) of both conductive elastomers 12 and 22 is set to d2, which is shorter than d1. Furthermore, the spacing between two adjacent conductive elastomers 12 and the spacing between two adjacent conductive elastomers 22 are both set to dg2, which is longer than dg1.

[0238] In Comparative Example 2, for example, Figure 24 As shown in (b), even if the substrate 21 is disposed at a distance dg1 offset from the positive X-axis direction, and the conductive elastomer 22 is disposed at a distance dg1 offset from the positive X-axis direction, it is still in harmony with... Figure 23Unlike case (b), the positive X-axis end of conductive elastomer 22 and the negative X-axis end of conductive elastomer 12 do not overlap. Therefore, in Comparative Example 2, even if a positional deviation from dg1 occurs in the X-axis direction during the installation of substrates 11 and 21, the conductive elastomers 12 and 22 of adjacent sensor sections will not conduct. Furthermore, similarly, if a positional deviation from dg1 occurs in the X-axis direction during the formation of conductive elastomers 12 and 22, the conductive elastomers 12 and 22 of adjacent sensor sections will not conduct.

[0239] However, in Comparative Example 2, since the spacing between adjacent conductive elastomers 12 and 22 is set to dg2, which is longer than dg1, the area where the load sensor 1 cannot detect the load, i.e., the insensitive zone, becomes larger compared to Comparative Example 1.

[0240] To this end, in order to avoid unexpected conduction and suppress insensitive bands, as in Reference Example 1, the inventors made the width of the short side of the conductive elastomer 12 formed on the substrate 11 and the width of the short side of the conductive elastomer 22 formed on the substrate 21 different from each other.

[0241] Figure 25 (a) and (b) are schematic diagrams of the structure of Reference Example 1, which shows that the width of the short side of the conductive elastomer 12 is different from the width of the short side of the conductive elastomer 22.

[0242] like Figure 25 As shown in (a), in Reference Example 1, the width of the conductive elastomer 12 in the short side direction (X-axis direction) is set to d1, and the width of the conductive elastomer 22 formed on the substrate 21 in the short side direction (X-axis direction) is set to d2, which is shorter than d1. Furthermore, the spacing between the two conductive elastomers 12 is set to dg1, and the spacing between the two conductive elastomers 22 is set to dg2, which is longer than dg1. d1 is, for example, about 10 mm, and dg1 is, for example, about 2 mm.

[0243] In reference example 1, for example, Figure 25 As shown in (b), even when the substrate 21 is disposed at a distance dg1 offset in the positive X-axis direction, and the conductive elastomer 22 is also offset at a distance dg1 in the positive X-axis direction, the end of the conductive elastomer 22 on the positive X-axis side and the end of the conductive elastomer 12 on the negative X-axis side do not overlap. That is, it avoids the conductive elastomer 22 constituting one sensor part from conducting with the conductive elastomer 12 constituting other sensor parts adjacent to one sensor part.

[0244] Thus, in Reference Example 1, even if the substrates 11 and 21 are offset from dg1 in the X-axis direction, the conductive elastomers 12 and 22 of adjacent sensor sections will not conduct. Furthermore, even if the conductive elastomers 12 and 22 are offset from dg1 in the X-axis direction during their formation, the conductive elastomers 12 and 22 of adjacent sensor sections will still not conduct. Therefore, the electrostatic capacitance based on adjacent sensor sections can be detected individually and appropriately.

[0245] Furthermore, in Reference Example 1, such as Figure 25 As shown in (a), although the spacing between adjacent conductive elastomers 22 is dg2, the spacing between adjacent conductive elastomers 12 is set to be shorter than dg2, dgl. This suppresses the region where the load sensor 1 cannot detect the load, i.e., the insensitive zone.

[0246] In addition, Figure 25 In (a) and (b), the change in electrostatic capacitance corresponding to the load is reduced in the area where only one of the conductive elastomers 12 and 22 is in contact with the coated copper wire 15 compared to the area where both conductive elastomers 12 and 22 are in contact. However, since a change in electrostatic capacitance corresponding to the load also occurs in the area where only one of the conductive elastomers 12 and 22 is in contact with the coated copper wire 15, this area does not become an insensitive zone and functions as the load detection range.

[0247] <See the effect in Example 1>

[0248] Based on Example 1, the above achieves the following effect.

[0249] The load sensor 1 according to Example 1 includes: a first substrate 11 and a second substrate 21 arranged face to face; a plurality of first conductive elastomers 12 formed in strip shape at a given interval on the opposing surface 11a of the first substrate 11; a plurality of second conductive elastomers 22 formed in strip shape opposite to the plurality of first conductive elastomers 12 on the opposing surface 21a of the second substrate 21; a conductive member (copper wire 15a) sandwiched between the plurality of first conductive elastomers 12 and the plurality of second conductive elastomers 22 and extending in a direction intersecting the first and second conductive elastomers; and a dielectric 15b disposed between the first conductive elastomers 12 and the second conductive elastomers 22 and the conductive member (copper wire 15a), wherein the widths of the plurality of first conductive elastomers 12 in the short side direction and the widths of the plurality of second conductive elastomers 22 in the short side direction are different from each other.

[0250] In the load sensor 1, the position where the conductive elastomers 12 and 22 intersect with the coated copper wire 15 forms the sensor section, and the load can be detected based on the change in electrostatic capacitance in the sensor section. In this case, since the widths of the conductive elastomers 12 and 22 are different, even if there is a positional deviation in the arrangement direction of the conductive elastomers 12 between them and the substrates 11 and 21 during the assembly of the load sensor 1, the conductive elastomers 12 and 22 constituting adjacent sensor sections can be prevented from conducting. Furthermore, since even reducing the spacing dgl of the wider conductive elastomer 12 can suppress the conduction between the conductive elastomers 12 and 22 caused by positional deviation, the spacing dg1 of the wider conductive elastomer 12 can be reduced. For this reason, the insensitive zone provided in the sensor section of the load sensor 1 can be reduced. Therefore, the load sensor 1 according to Reference Example 1 can avoid unexpected conduction and suppress the insensitive zone.

[0251] The copper wire 15a (conductive member) with copper coating 15 is a linear conductor, and the dielectric 15b is coated around the copper wire 15a. If the copper wire 15a is composed of linear conductors in this way, then the portion between the vertically arranged conductive elastomers 12 and 22 without copper wire 15a becomes prone to a situation where adjacent rows of diagonally opposed conductive elastomers 12 and 22 come into contact due to positional misalignment. However, in Reference Example 1, as... Figure 25 As shown in (a) and (b), since the width of the short side of the conductive elastomer 12 is different from the width of the short side of the conductive elastomer 22, unexpected conduction can be avoided.

[0252] <Reference Example 2>

[0253] In Reference Example 1 above, the four corner vertices of substrate 11 and the four corner vertices of substrate 21 are joined together by connecting them with a silicone rubber adhesive. In contrast, in Reference Example 2, substrate 11 and substrate 21 are joined together by sewing the peripheral portions of substrate 11 and substrate 21 together with thread members.

[0254] Figure 26 This is a top view schematically illustrating the specific structure of the load sensor 1 in Reference Example 2. Figure 26 For convenience, the load detection unit 1a located inside the load sensor 1 is shown in solid line.

[0255] exist Figure 26 In the load sensor 1 shown, with Figure 22As shown in the dashed lines, the load sensor 1 is assembled by stitching the outer periphery of substrates 11 and 21 together with thread members 300. The seams of the thread members 300 are formed in a straight line along the outline of substrates 11 and 21. The thread members 300 are composed of lower thread 301 and upper thread 302. The thread members (lower thread 301 and upper thread 302) are made of chemical fibers, natural fibers, or blends thereof. Other structures in Reference Example 2 are the same as in Reference Example 1.

[0256] Figure 27 (a) is through Figure 26 The XZ plane of the seam located on the negative side of the Y-axis cuts off the A-A' cross-section of load sensor 1.

[0257] Through the stitching of substrates 11 and 21, the pinhole 41 penetrating substrates 11 and 21 in one direction (Z-axis direction) Figure 27 In case (a), the threads are arranged in the X-axis direction to be parallel to the outline of the substrates 11 and 21. The upper thread 302 passes through the pinhole 41 from the positive Z-axis side, and the upper thread 302 and lower thread 301 are engaged near the negative Z-axis side of the pinhole 41. The spacing of the pinholes 41 arranged in one direction is set to p. The thickness of substrate 11 is set to t1, and the thickness of substrate 21 is set to t2. Through the stitching of the thread members 300, the lower thread 301 presses substrate 11 in the positive Z-axis direction, and the upper thread 302 presses substrate 21 in the negative Z-axis direction. Thus, substrate 11 and substrate 21 are joined.

[0258] Here, if the spacing p of the pinholes 41 is short, although the adhesion between the substrate 11 and the substrate 21 is improved, if the direction of the substrates 11 and 21 is extended in the XY plane (e.g., ... Figure 27 When a tensile force is applied to substrates 11 and 21 in (a) along the Y-axis direction perpendicular to the A-A' section, a problem arises where substrates 11 and 21 crack along the seam of the filament member 300. To address this, the inventors actually fabricated multiple load sensors 1 stitched together at different intervals p, applying a given tensile force to verify the conditions that prevent substrates 11 and 21 from cracking along the seam.

[0259] The verification conditions are as follows. The yarn component 300 (lower yarn 301 and upper yarn 302) is made of King polyester #60 manufactured by FUJIX Co., Ltd. The substrates 11 and 21 are made of compounded silicone rubber. The thickness t1 of substrate 11 and the thickness t2 of substrate 21 are set to be equal, and the thicknesses t1 and t2 are set to any one of 0.5 mm, 1.0 mm, and 1.5 mm. The spacing p of the pinholes 41 is set to any one of 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, and 3.0 mm. Eighteen types of load sensors 1 are fabricated by combining the thicknesses t1 and t2 with the spacing p. By applying tensile force to the 18 types of load sensors 1 in the positive and negative X-axis directions, respectively, the presence of tensile force on the near-center of the positive and negative X-axis sides of the substrates 11 and 21 is used to verify whether the substrates 11 and 21 crack along the seam. During the verification, the tensile force is gradually increased.

[0260] Figure 27 Table (b) shows the results of the verification conducted by the inventors. “○” indicates that the substrates 11 and 21 did not crack along the seam, and “×” indicates that the substrates 11 and 21 cracked along the seam. In the case of “○”, although the substrates 11 and 21 did not crack along the seam, they were torn off due to local cracking near the tensile force given the tensile force.

[0261] The results of this verification show that although the tensile force at which substrates 11 and 21 begin to crack along the joint is roughly the same whether or not they crack along the joint, the tensile force required to further develop cracks differs. Specifically, when substrates 11 and 21 crack along the joint, cracking begins at the joint and continues along the joint with a weak tensile force. Conversely, when substrates 11 and 21 do not crack along the joint, cracking begins at the joint, and by applying a considerably strong tensile force, localized cracks only occur near the area where the tensile force was applied. Therefore, it can be said that when substrates 11 and 21 crack along the joint, their strength is low, and when they do not crack along the joint, their strength is high.

[0262] Furthermore, if the substrates 11 and 21 crack along the joint, the crack extends along the joint, not only near the center of the edge that has been subjected to tensile force, but also near both ends of the edge. On the other hand, if the substrates 11 and 21 do not crack along the joint, the crack terminates near the center of the edge that has been subjected to tensile force.

[0263] Therefore, from the viewpoint of the strength of the substrates 11 and 21 and the extent of crack propagation in the substrates 11 and 21, it is preferable that the substrates 11 and 21 do not crack along the joint.

[0264] like Figure 27 As shown in Table (b), when the thicknesses t1 and t2 of substrates 11 and 21 are 0.5 mm, if the spacing p is 2.5 mm or less, substrates 11 and 21 will crack along the joint. When the thicknesses t1 and t2 of substrates 11 and 21 are 1.0 mm, if the spacing p is 1.0 mm or less, substrates 11 and 21 will crack along the joint. When the thicknesses t1 and t2 of substrates 11 and 21 are 1.5 mm, if the spacing p is 0.5 mm, substrates 11 and 21 will crack along the joint.

[0265] Based on the above results, the inventors believe that in order to prevent the substrates 11 and 21 from cracking along the joint, the following equations (1) and (2) need to be satisfied.

[0266] p≥1.5 / t1…(1)

[0267] p≥1.5 / t2…(2)

[0268] That is, the inventors discovered that when both equations (1) and (2) above are satisfied, in other words, when the substrate with the smaller thickness among the substrates 11 and 21 satisfies the equation, the substrates 11 and 21 do not crack along the seam. Therefore, in the load sensor 1 of Reference Example 2, the spacing p is set so that both equations (1) and (2) above are satisfied.

[0269] <See the effect of Example 2>

[0270] Based on Example 2, the above achieves the following effect.

[0271] The load sensor 1 described in Reference Example 2 includes: two substrates 11 and 12 arranged face to face; and a load detection part 1a sandwiched between the two substrates 11 and 12. The two substrates 11 and 12 are joined together by stitching their outer peripheries together with a thread member 300. The spacing p of the pinholes 41 formed by stitching in one direction is more than 1.5 times the reciprocal of the thickness of the substrate 11.

[0272] Here, the load detection unit 1a and Figure 18 (a)~ Figure 22Reference Example 1 shown also includes: a plurality of first conductive elastomers 12 in strip shape formed at a given interval on the opposing surface 11a of one of the substrates 11; a plurality of second conductive elastomers 22 in strip shape formed on the opposing surfaces 21a of other substrates 21 respectively opposite to the plurality of first conductive elastomers 12; a conductive member (copper wire 15a) sandwiched between the plurality of first conductive elastomers 12 and the plurality of second conductive elastomers 22 and extending in a direction intersecting the first conductive elastomers 12 and the second conductive elastomers 22; and a dielectric 15b disposed between the first conductive elastomers 12 and the second conductive elastomers 22 and the conductive member (copper wire 15a).

[0273] When the pinholes 41 are arranged in one direction, cracks may occur between the pinholes 41 due to the tensile force in the direction of expansion of the substrates 11 and 21, depending on the spacing between the pinholes 41, causing the substrates 11 and 21 to crack at the joint. In contrast, in Reference Example 2, as shown in equations (1) and (2) above, since the spacing p of the pinholes 41 formed by stitching in one direction is set to be more than 1.5 times the reciprocal of the thickness of the substrates 11 and 21, as verified above, even when a tensile force is applied in the direction of expansion of the substrates 11 and 21, the substrates 11 and 21 are unlikely to crack at the joint. Therefore, the strength of the substrates 11 and 21 can be improved.

[0274] <Reference Example 3>

[0275] In Reference Example 2 above, the seam of the wire member 300 is formed in a straight line along the outline of the substrates 11 and 21. In contrast, in Reference Example 3, as... Figure 28 As shown, the seam of the thread member 300 is formed in a zigzag shape while following the outer contour. In Reference Example 3, the substrates 11 and 21 are also joined together by stitching the outer periphery with the thread member 300. The other structures of Reference Example 3 are the same as those of Reference Example 2.

[0276] Figure 29 (a) is in Figure 28 A top view of the outer periphery of substrates 11 and 21 on the negative Y-axis side, viewed from the negative Z-axis direction.

[0277] Through the stitching of substrates 11 and 21, pinholes 41 and 42 are formed penetrating through substrates 11 and 21 vertically (in the Z-axis direction). Near the outer periphery of substrates 11 and 21, a pinhole row C1 of pinholes 41 and a pinhole row C2 of pinholes 42 arranged in a straight line along the outer shape are formed. Figure 29In (a), since the shapes of the substrates 11 and 21 extend in the X-axis direction, the pinhole rows C1 and C2 also extend in the X-axis direction. Pinhole row C1 is formed outside pinhole row C2, and the interval between pinhole row C1 and pinhole row C2 is w1.

[0278] Pinholes 41 are arranged along a straight line of pinholes C1 at a fixed interval p, and pinholes 42 are arranged along a straight line of pinholes C2 at a fixed interval p. Adjacent pinholes 41 and 42 are arranged along the direction of their outer shape (…). Figure 29 The interval in (a) is p / 2 (in the X-axis direction).

[0279] Figure 29 (b) is in Figure 29 (a) shows the B-B' cross-sectional view when the load sensor 1 is cut through the XZ plane passing through the pinhole 41. Figure 29 In (b), the upper wire 302 passing through the pinhole 42 located further inside the cut surface (positive Y-axis side) is shown in dashed lines.

[0280] like Figure 29 As shown in (b), when viewed in the direction perpendicular to the pinhole rows C1 and C2 (positive Y-axis direction), pinholes 41 and 42 are arranged alternately. Furthermore, in Reference Example 3, the distance p between two adjacent pinholes 41 and the distance p between two adjacent pinholes 42 are also set to satisfy equations (1) and (2) shown in Reference Example 2 above.

[0281] <See the effect in Example 3>

[0282] Based on Example 3, the above achieves the following effect.

[0283] The load sensor 1 according to Example 3 includes: two substrates 11 and 21 arranged face to face; and a load detection part 1a arranged between the two substrates 11 and 21. The two substrates 11 and 21 are joined together by stitching together near their outer peripheries with a thread member 300. The pinholes 41 and 42 formed by the stitching are arranged in at least two rows. The pinholes 41 in one row are displaced relative to the pinholes 42 in the other rows in the direction in which the row extends.

[0284] Here, the load detection unit 1a and Figure 18 (a)~ Figure 22Similarly, Reference Example 1 shown includes: a plurality of first conductive elastomers 12 formed in strips at given intervals on the opposing surface 11a of one substrate 11; a plurality of second conductive elastomers 22 formed in strips on the opposing surfaces 21a of other substrates 21, respectively opposite to the plurality of first conductive elastomers 12; a conductive member (copper wire 15a) sandwiched between the plurality of first conductive elastomers 12 and the plurality of second conductive elastomers 22 and extending in a direction intersecting the first conductive elastomers 12 and the second conductive elastomers 22; and a dielectric 15b disposed between the first conductive elastomers 12 and the second conductive elastomers 22 and the conductive member (copper wire 15a).

[0285] When only pinhole row C1 is provided and the spacing p of pinhole 41 is set to be large, as shown in Comparative Example 3 below, the adhesion between the two substrates 11 and 21 weakens within the range between adjacent pinholes 41, and the waterproof and dustproof performance is reduced.

[0286] Figure 30 (a) is a top view of the outer periphery of the substrates 11 and 21 on the negative Y-axis side, viewed from the negative Z-axis direction in the case of Comparative Example 3. In Comparative Example 3, compared with Reference Example 3, pinhole 42 is omitted, and only pinhole 41 is formed. Figure 30 (b) is in Figure 30 In (a), the C-C' cross-section of the load sensor 1 is cut off by the XZ plane passing through the pinhole 41. Figure 30 As shown in (b), in Comparative Example 3, a gap is formed between substrate 11 and substrate 21 near the middle of adjacent pinholes 41. If such a gap is formed, water and dust may penetrate into the interior of the load sensor 1.

[0287] In contrast, in Reference Example 3, such as Figure 29 As shown in (a) and (b), the pinholes 41 and 42 formed by stitching are arranged in two rows, with the pinholes 42 in row C2 being shifted relative to the pinholes 41 in row C1 in the direction extending from rows C1 and C2. Therefore, the lateral area between adjacent pinholes 41 in row C1 is stitched together with the pinholes 42 in row C2, and the lateral area where the adhesion is weakened by stitching the pinholes 41 in row C1 is improved by stitching the pinholes 42 in row C2. Thus, when all pinholes 41 and 42 are stitched together, the adhesion between the two substrates 11 and 21 can be improved throughout the entire area. Therefore, the waterproof and dustproof performance of the load sensor 1 can be improved.

[0288] The spacing p of pinholes 41 in pinhole row C1 and the spacing p of pinholes 42 in pinhole row C2 are both set to be at least 1.5 times the reciprocal of the thickness of the substrates 11 and 21. Therefore, as shown in Reference Example 2 above, even when tensile force is applied in the direction extending the substrates 11 and 21, the substrates 11 and 21 are less likely to crack at the joint, thus improving their strength. Thus, in Reference Example 3, pinhole rows C1 and C2 can be provided to improve waterproof and dustproof performance, and the spacing p is set large to prevent the substrates 11 and 21 from cracking.

[0289] exist Figure 29 In example (a), the pinholes 41 and 42 formed by the stitching are arranged in two columns.

[0290] In addition, Figure 29 In example (a), the thread member 300 alternately passes through the pinholes 41 of one column (pinhole column C1) and the pinholes 42 of the other column (pinhole column C2). Thus, the two substrates 11 and 21 can be reliably joined together by the stitching of the thread member 300.

[0291] A pinhole 42 from the other column (pinhole column C2) is positioned to the side (positive Y-axis side) at the midpoint of adjacent pinholes 41 in one column (pinhole column C1). Thus, the adhesion is improved by stitching the pinholes 42 from pinhole column C2 to the side where the adhesion is weakest due to the stitching of the pinholes 41 in pinhole column C1. Therefore, the adhesion between the two substrates 11 and 21 can be improved more effectively.

[0292] <Example of a modified reference example>

[0293] Besides the structure shown in the reference example above, the structure of load sensor 1 can be modified in various ways.

[0294] For example, in the above-mentioned Reference Example 3, the thread member 300 sews the substrates 11 and 21 so that they alternately pass through the needle holes 41 and 42. However, the sewing of the thread member to the needle holes 41 and 42 is not limited to this. For example, it can also be done as in the following Modification Examples 1 and 2.

[0295] Figure 31 (a) is a top view of the outer periphery of the substrates 11 and 21 on the negative Y-axis side, as described in the modified example 1, when viewed in the negative Z-axis direction.

[0296] In Modification 1, similar to Reference Example 3, pinholes 41 and 42 are formed on substrates 11 and 21, forming pinhole rows C1 and C2. However, in Modification 1, in the stitching of substrates 11 and 21, not only is thread member 300 used, but also thread member 500, which is the same as thread member 300. That is, the thread member has a first thread member 300 that passes through the pinholes 41 in one row (pinhole row C1) and a second thread member 500 that passes through the pinholes 42 in the other row (pinhole row C2). Thread member 500 is composed of a lower thread 501 and an upper thread 502. In Modification 1, thread member 300 is used only for stitching pinholes 41, and thread member 500 is used only for stitching pinholes 42.

[0297] In Change Example 1, as well as... Figure 31 As in (a), the pinholes 42 of the other column (pinhole column C2) are arranged to the side (positive Y-axis side) at the middle position of adjacent pinholes 41 in the column (pinhole column C1) of one party.

[0298] Figure 31 (b) is in Figure 31 The D-D' cross-sectional view of load sensor 1 is shown in (a) when the XZ plane passing through the pinhole 41 cuts through it.

[0299] In Modification 1, the pinholes 41 are arranged at a spacing p along pinhole column C1, and the pinholes 42 are arranged at a spacing p along pinhole column C2. Furthermore, the spacing p is set to satisfy equations (1) and (2) shown in Reference Example 2 above. This prevents the substrates 11 and 21 from cracking along pinhole columns C1 and C2. In addition, in Modification 1, similar to Reference Example 3 above, since the lateral portion of the area between adjacent pinholes 41 in pinhole column C1 is stitched together through pinholes 42 in pinhole column C2, the adhesion between the two substrates 11 and 21 is improved. This improves the waterproof and dustproof performance of the load sensor 1.

[0300] Furthermore, in Modified Example 1, since the use of the thread member 300 that passes through the pinhole 41 of pinhole row C1 and the thread member 500 that passes through the pinhole 42 of pinhole row C2, the two substrates 11 and 21 can be more reliably joined by the stitching of the thread members 300 and 500.

[0301] Figure 32 (a) is a top view of the outer periphery of the substrates 11 and 21 on the negative Y-axis side, as described in Modification Example 2, in the negative Z-axis direction.

[0302] In Modification 2, similar to Reference 3, pinholes 41 and 42 are formed on substrates 11 and 21, forming pinhole rows C1 and C2. However, in Modification 2, the order in which the thread member 300 stitches the pinholes 41 and 42 is different from that in Reference 3. In Modification 2, pinholes 41 and 42 are not stitched alternately, but rather pinhole 41 is stitched twice consecutively, followed by pinhole 42 being stitched twice consecutively. Thus, as... Figure 32 As shown in (a), the substrates 11 and 21 are sewn together so that the thread member 300 is bent. In modified example 2, the same effect is achieved as in reference example 3.

[0303] Furthermore, in the above-mentioned Reference Example 3, the needle holes formed by sewing are arranged in two rows, but it is not limited to this and can also be arranged in three or more rows.

[0304] Figure 32 (b) is a top view of the outer periphery of the substrates 11 and 21 on the negative Y-axis side, as described in Modification Example 3, from the negative Z-axis direction.

[0305] In Modification Example 3, compared to Modification Example 2, in addition to the pinhole rows C1 and C2, a pinhole row C3 consisting of pinholes 43 is also provided. Pinhole row C3 is located between pinhole row C1 and the outer edges of substrates 11 and 21, and is parallel to pinhole rows C1 and C2. The positions of pinholes 41, 42, and 43 in the X-axis direction are different from each other. In the X-axis direction, the intervals between pinholes 41 and 42, between pinholes 42 and 43, and between pinholes 43 and 41 are all p / 3. In Modification Example 3, in the stitching of substrates 11 and 21, not only are thread members 300 and 500 used, but also a thread member 600, which is the same as thread members 300 and 500. Thread member 600 consists of a lower thread 601 and an upper thread 602, and is used only for stitching pinholes 43.

[0306] In Modification Example 3, the positive and negative Y-axis sides of the range between adjacent pinholes 41 in pinhole row C1 are stitched together using pinholes 42 in pinhole row C2 and pinholes 43 in pinhole row C3, respectively. This improves the fit between the sides of the range where the fit is weakened by stitching pinholes 41, by stitching pinholes 42 and 43. Therefore, the waterproof and dustproof performance of the load sensor 1 can be further improved.

[0307] In the X-axis direction, the intervals between pinholes 41 and 42, pinholes 42 and 43, and pinholes 43 and 41 can also be different from p / 3. Pinholes 42 and 43 can be positioned laterally in the X-axis direction by shifting them relative to each other in the region between pinholes 41.

[0308] Furthermore, in the above-described reference example, the conductive elastomers 12 and 22 are formed on the opposing surfaces 11a and 21a respectively using a given printing method. However, this is not a limitation; the conductive elastomers 12 and 22 may also be applied to the opposing surfaces 11a and 21a respectively using an adhesive or the like.

[0309] Furthermore, in the above-described reference example, the width of the conductive elastomer 22 on the substrate 21 side is set to be shorter than the width of the conductive elastomer 12 on the substrate 11 side, but it is not limited to this. Alternatively, the width of the conductive elastomer 12 on the substrate 11 side may be set to be shorter than the width of the conductive elastomer 22 on the substrate 21 side.

[0310] Furthermore, in Reference Example 1 above, the load sensor 1 includes multiple coated copper wires 15, but having at least one coated copper wire 15 is sufficient. For example, the coated copper wire 15 included in the load sensor 1 may also be a single wire. In Reference Examples 2 and 3 above, the load sensor 1 may include at least one conductive elastomer 12 and at least one coated copper wire 15.

[0311] Furthermore, in the aforementioned reference example, instead of the copper-coated wire 15, an electrode can be used consisting of a linear conductive member made of a material other than copper and a dielectric coating the conductive member. In this case, the conductive member of the electrode is, for example, composed of a metal body, a glass body with a conductive layer formed on its surface, a resin body with a conductive layer formed on its surface, etc.

[0312] Furthermore, in the above-mentioned reference example, the structure of the load sensor 1 does not necessarily have to be a combination of coated copper wire 15 and conductive elastomer 12. For example, it can also be a structure with a stretchable dielectric sandwiched between the upper and lower electrodes.

[0313] Furthermore, in the above reference example, Figure 19 The load detection unit 1a shown in (b) and sandwiched between substrates 11 and 21 is not limited to the structure described above.

[0314] Furthermore, in the structures of Reference Examples 2 and 3, the structure of the load detection unit 1a does not necessarily have to be the same as that of Reference Example 1. For example, in Reference Examples 2 and 3, the widths of the conductive elastomers 12 and 22 in the short side direction of the load detection unit 1a can be the same. In this case, the crack prevention effect of the substrates 11 and 21 in Reference Example 2 and the improved adhesion effect of the substrates 11 and 21 in Reference Example 3 can be achieved.

[0315] Furthermore, in Reference Examples 1 to 3 and their variations, a conductor wire 13 made of stranded wire may be used instead of the copper-coated wire 15.

[0316] Furthermore, various modifications can be made to the embodiments of the present invention within the scope of the technical concept shown in the claims.

[0317] Explanation of reference numerals in the attached figures

[0318] 1. Load sensor

[0319] 11, 21 Substrates (Substrate 1, Substrate 2)

[0320] Opposite surfaces 11a and 21a

[0321] 12, 22 Conductive elastomers (other conductive elastomers)

[0322] 13 A pair of conductor wires (conductor wires)

[0323] Conductor wires 13a and 13b

[0324] 30 wire

[0325] 31 Copper wire (conductive component)

[0326] 32 Dielectric

[0327] Sensor sections A, A11~A13, A21~A23, A31~A33

[0328] R is the measurement area.

Claims

1. A load sensor, comprising: The first substrate and the second substrate are arranged face to face with each other; A conductive elastomer disposed on the opposing surface of the first substrate; and A conductor wire, disposed between the second substrate and the conductive elastomer, is formed by twisting together multiple wires. The wire is constructed by coating the surface of a linear conductive component with a dielectric material. The twist pitch of the plurality of wires satisfies the following condition: p≤12nd Here, the parameters shown in the above equations are defined as follows: p: Twist pitch of multiple wires n: The number of wires contained in the conductor wire d: Outer diameter of the wire.

2. The load sensor according to claim 1, wherein, The conductive elastomers are arranged in plurality at given intervals on the opposite surface of the first substrate. The conductor lines are configured to intersect with the plurality of conductive elastomers.

3. The load sensor according to claim 1 or 2, wherein, The conductive elastomer has a strip-like shape that is long in a direction perpendicular to the direction in which the conductor line extends. The conductor lines are configured to intersect the conductive elastomer in multiple ways.

4. The load sensor according to claim 1 or 2, wherein, The load sensor includes: Other conductive elastomers are disposed opposite to the conductive elastomer on the opposing surface of the second substrate. The conductor wire is disposed between the conductive elastomer and the other conductive elastomers.

5. The load sensor according to claim 1 or 2, wherein, The conductor wire is arranged in a wave shape in a plane parallel to the first substrate and the second substrate.

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