Load sensor
Patent Information
- Application Number
- JP2023566137
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-21
- Filing Date
- 2022-10-21
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2042-10-21
AI Technical Summary
Existing load sensors face difficulties in properly sewing a large number of conductor wires due to the narrow distance between them, which is exacerbated by the minimum needle hole pitch of sewing machines, making it challenging to secure each wire effectively.
The load sensor design includes a first and second base member with conductive elastic bodies and conductor wires arranged such that they intersect or approach each other at specific positions, allowing for wider spacing and proper sewing by threading, which accommodates the minimum needle hole pitch of sewing machines.
This design enables the proper sewing and securing of multiple conductor wires, enhancing the accuracy of load detection while preventing overlap and potential damage to the dielectric material, thus improving the overall performance and reliability of the load sensor.
Abstract
Description
Load Sensor
[0001] The present invention relates to a load sensor that detects an externally applied load based on a change in capacitance.
[0002] Load sensors are widely used in fields such as industrial equipment, robots, and vehicles. In recent years, with the advancement of computer-based control technology and improvements in design, there has been progress in the development of electronic devices that make use of a variety of free-form surfaces, such as humanoid robots and automobile interior fittings. Accordingly, there is a demand for high-performance load sensors to be attached to each free-form surface.
[0003] The following Patent Document 1 describes a pressure-sensitive element (load sensor) that includes a sheet-like substrate having an elastic conductive portion, a plurality of conductor wires arranged so as to cross the elastic conductive portion, a plurality of dielectrics respectively arranged between the plurality of conductor wires and the elastic conductive portion, and a thread-like member that sews the plurality of conductor wires to the substrate.
[0004] International Publication No. 2020 / 153029
[0005] In the load sensor described above, a sewing machine is used to sew the multiple conductor wires to the base material. However, when a large number of conductor wires are arranged in the load sensor, the spacing between adjacent conductor wires becomes narrow, making it difficult to properly sew each conductor wire to the base material.
[0006] In view of the above problem, an object of the present invention is to provide a load sensor in which a plurality of conductor wires can be properly sewn to a base member.
[0007] A main aspect of the present invention relates to a load sensor. The load sensor according to this aspect includes a first base member, a second base member arranged opposite the first base member, a plurality of conductive elastic bodies arranged side by side on opposing surfaces of at least one of the first and second base members, a plurality of conductor wires arranged to intersect the conductive elastic bodies, a dielectric body arranged between the conductive elastic bodies and the conductor wires, and a thread that sews the plurality of conductor wires to the first or second base member with a row of stitches extending in a direction intersecting the arrangement direction of the conductive elastic bodies. The plurality of conductor wires are arranged so that one of the conductor wires intersects or is close to another of the conductor wires at the position of the row of stitches, and the thread is sewn to the first or second base member so as to straddle the one conductor wire and the other conductor wire that intersect or are close to each other.
[0008] The load sensor according to this aspect allows multiple conductor wires that intersect or approach each other at a stitching row position to be sewn together to the first base member or the second base member. In this case, the intervals between the positions where the multiple conductor wires intersect or approach each other (sewn-up positions) are wider than the intervals when the multiple conductor wires are simply lined up. Generally, sewing machines for sewing threads have a minimum needle hole pitch based on machine precision. Therefore, even if it is not possible to sew up multiple lined-up conductor wires one by one due to the minimum needle hole pitch, the load sensor according to this aspect allows each conductor wire to be properly sewn up because the intervals between the stitched-up positions are wide, as described above.
[0009] As described above, according to the present invention, it is possible to provide a load sensor in which a plurality of conductor wires can be properly sewn to a base member.
[0010] The effects and significance of the present invention will become more apparent from the following description of the embodiments, however, the embodiments shown below are merely examples of how the present invention can be implemented, and the present invention is not limited to the embodiments described below.
[0011] FIG. 1 is a plan view schematically showing the configuration of a structure during a manufacturing process according to the first embodiment. FIG. 2 is a plan view schematically showing the configuration of a structure during a manufacturing process according to the first embodiment. FIG. 3 is a plan view schematically showing the configuration of a structure during a manufacturing process according to the first embodiment. FIG. 4 is a plan view schematically showing the configuration of a wire structure according to the first embodiment. FIG. 5 is a diagram schematically showing a cross section of a structure according to the first embodiment, when cut along a plane parallel to the X-Z plane at the position of a thread. FIG. 6 is a perspective view schematically showing the configuration of a load sensor according to the first embodiment. FIGS. 7(a) and 7(b) are diagrams schematically showing a cross section near the intersection position of a conductive elastic body and a wire according to the first embodiment, when cut along a plane parallel to the X-Z plane at the intersection position of the conductive elastic body and the wire. FIG. 8 is a plan view schematically showing the internal configuration of a load sensor according to the first embodiment. FIG. 9(a) is a plan view schematically showing the spacing of stitches of a thread according to a comparative example. FIG. 9(b) is a plan view schematically showing the spacing of stitches of a thread according to the first embodiment. FIG. 10 is a plan view showing the configuration of a wire structure according to a first modification of the first embodiment. FIG. 11 is a plan view showing the configuration of a wire structure according to a second modification of the first embodiment. FIG. 12 is a plan view showing the configuration of a wire structure according to a third modification of the first embodiment. FIG. 13 is a plan view showing the configuration of a wire structure according to the second embodiment. FIG. 14 is a plan view schematically showing the intervals between stitches of thread according to the second embodiment. FIG. 15 is a plan view showing the configuration of a wire structure according to a first modification of the second embodiment. FIG. 16 is a plan view showing the configuration of a wire structure according to a second modification of the second embodiment. FIG. 17 is a plan view showing the configuration of a wire structure according to a third modification of the second embodiment. FIG. 18 is a diagram schematically showing a cross section near an intersection position when cutting along a plane parallel to the X-Z plane at the intersection position of a conductive elastic body and a wire according to another modification.
[0012] However, the drawings are for illustrative purposes only and do not limit the scope of the present invention.
[0013] The load sensor according to the present invention can be applied to a load sensor for a management system or electronic device that performs processing in response to an applied load.
[0014] Examples of management systems include inventory management systems, driver monitoring systems, coaching management systems, security management systems, and nursing care / childcare management systems.
[0015] In an inventory management system, for example, a load sensor installed on a stock shelf detects the weight of the stock piled up, and detects the type and number of products on the stock shelf. This allows for efficient inventory management and labor savings in stores, factories, warehouses, etc. Furthermore, a load sensor installed inside a refrigerator detects the weight of food in the refrigerator, and detects the type, number, and amount of food in the refrigerator. This allows for automatic menu suggestions using the food in the refrigerator.
[0016] In a driver monitoring system, for example, a load sensor provided in the steering device monitors the load distribution of the driver on the steering device (e.g., grip force, grip position, pedal force). Also, a load sensor provided in the vehicle seat monitors the load distribution of the driver on the vehicle seat while seated (e.g., center of gravity position). This makes it possible to provide feedback on the driver's driving state (drowsiness, psychological state, etc.).
[0017] In a coaching management system, for example, load sensors installed in the bottom of shoes monitor the load distribution on the soles of the feet, which can correct or guide the wearer to an appropriate walking or running state.
[0018] In a security management system, for example, load sensors installed on the floor detect the load distribution as a person passes through, and detect the person's weight, stride length, passing speed, shoe sole pattern, etc. By comparing this detected information with data, it becomes possible to identify the person who has passed through.
[0019] In a caregiving / childcare management system, for example, load sensors installed on bedding and toilet seats monitor the distribution of load on the human body relative to the bedding and toilet seat. This makes it possible to estimate what actions the person is about to take in relation to the position of the bedding and toilet seat and prevent falls.
[0020] Examples of electronic devices include in-vehicle devices (car navigation systems, audio equipment, etc.), home appliances (electric kettles, induction cooking heaters, etc.), smartphones, electronic paper, electronic book readers, PC keyboards, game controllers, smart watches, wireless earphones, touch panels, electronic pens, penlights, luminous clothing, musical instruments, etc. In electronic devices, a load sensor is provided in an input unit that receives input from a user.
[0021] The load sensor in the following embodiments is a capacitance type load sensor that is typically provided in the load sensors of the management systems and electronic devices described above. Such load sensors are sometimes called "capacitive pressure-sensitive sensor elements," "capacitive pressure detection sensor elements," "pressure-sensitive switch elements," etc. The load sensors in the following embodiments are connected to a detection circuit, and the load sensor and the detection circuit constitute a load detection device. The following embodiments are one embodiment of the present invention, and the present invention is not limited to the following embodiments in any way.
[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, each drawing is labeled with X, Y, and Z axes which are orthogonal to each other. The Z axis direction is the height direction of the load sensor 1.
[0023] First Embodiment FIG. 1 is a plan view schematically showing the configuration of a structure 1a in a manufacturing process.
[0024] The structure 1 a includes a first base member 11 , a plurality of conductors 12 , a plurality of conductive elastic bodies 13 , a plurality of wirings 14 , and a plurality of electrodes 15 .
[0025] The first base member 11 is an elastic, flat-plate-like member. The first base member 11 has a rectangular shape in a plan view. The thickness of the first base member 11 is constant. When the thickness of the first base member 11 is small, the first base member 11 is sometimes called a sheet member or a film member.
[0026] The first base member 11 is insulating and is made of, for example, a non-conductive resin material or a non-conductive rubber material. The resin material used for the first base member 11 is, for example, at least one resin material selected from the group consisting of styrene-based resins, silicone-based resins (e.g., polydimethylpolysiloxane (PDMS)), acrylic-based resins, rotaxane-based resins, and urethane-based resins. The rubber material used for the first base member 11 is, for example, at least one rubber material selected from the group consisting of 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.
[0027] The conductors 12 are formed on the opposing surface 11a (the surface on the negative side of the Z axis) of the first base member 11. Here, five conductors 12 are arranged on the opposing surface 11a of the first base member 11 so as to extend in the X axis direction. The conductors 12 are made of a material with lower resistance than the conductive elastic body 13. In the first embodiment, the conductors 12 are elastic, conductive members, and the thickness of the conductors 12 is smaller than the thickness of the conductive elastic body 13. Wiring 14 is drawn out from the end of each conductor 12 on the negative side of the X axis.
[0028] The conductive elastic bodies 13 are formed on the opposing surface 11a of the first base member 11 so as to cover the conductors 12. The conductive elastic bodies 13 are formed on the opposing surface 11a so that the conductors 12 are positioned approximately in the middle of the conductive elastic bodies 13 in the Y-axis direction. Here, five conductive elastic bodies 13 are arranged on the opposing surface 11a of the first base member 11. The five conductive elastic bodies 13 have the same width, length, and thickness.
[0029] Each conductive elastic body 13 has a strip-like shape that is long in the X-axis direction and is aligned in the Y-axis direction with a predetermined gap between them. That is, the long sides of the conductive elastic bodies 13 are parallel to the X-axis, and the alignment direction of the conductive elastic bodies 13 is parallel to the Y-axis. The conductive elastic bodies 13 are elastic, conductive members. The conductors 12 and the conductive elastic bodies 13 formed to cover the conductors 12 are electrically connected.
[0030] The conductor 12 and the conductive elastic body 13 are formed on the opposing surface 11a of the first base member 11 by a printing method such as screen printing, gravure printing, flexographic printing, offset printing, or gravure offset printing. The conductive elastic body 13 is formed so as to overlap the conductor 12 after the conductor 12 is formed. These printing methods make it possible to form the conductor 12 and the conductive elastic body 13 on the opposing surface 11a of the first base member 11 to a thickness of approximately 0.001 mm to 0.5 mm. However, the method of forming the conductor 12 and the conductive elastic body 13 is not limited to the printing method.
[0031] The conductor 12 and the conductive elastic body 13 are made of a resin material with a conductive filler dispersed therein, or a rubber material with a conductive filler dispersed therein.
[0032] The resin material used for the conductor 12 and the conductive elastic body 13 is, like the resin material used for the first base member 11 described above, at least one resin material selected from the group consisting of styrene-based resins, silicone-based resins (polydimethylpolysiloxane (e.g., PDMS)), acrylic-based resins, rotaxane-based resins, and urethane-based resins. The rubber material used for the conductor 12 and the conductive elastic body 13 is, like the rubber material used for the first base member 11 described above, at least one rubber material selected from the group consisting of 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.
[0033] The conductive filler used in the conductor 12 and the conductive elastic body 13 may be, for example, Au (gold), Ag (silver), Cu (copper), C (carbon), ZnO (zinc oxide), In 2 O 3 (indium(III) oxide), and SnO 2 The conductive material is at least one material selected from the group consisting of metal materials such as tin (IV) oxide, conductive polymer materials such as PEDOT:PSS (i.e., a composite of poly3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS), and conductive fibers such as metal-coated organic fibers and metal wires (in a fibrous state).
[0034] In the first embodiment, the conductive filler used in the conductor 12 is Ag (silver), and the conductive filler constituting the conductive elastic body 13 is C (carbon).
[0035] The wiring 14 is formed on the opposing surface 11a (the surface on the negative side of the Z axis) of the first base member 11. The electrodes 15 are formed near the end of the opposing surface 11a of the first base member 11 on the positive side of the Y axis. Here, five electrodes 15 are lined up in the X axis direction with a predetermined gap between them. The wiring 14 and the electrodes 15 are made of a conductive material. Each wiring 14 electrically connects one conductor 12 and one electrode 15 that make a pair.
[0036] FIG. 2 is a plan view schematically showing the configuration of the structure 1b in the manufacturing process.
[0037] The structure 1 b includes a substrate 21 , a plurality of electrodes 22 , a plurality of electrodes 23 , and a plurality of wires 30 .
[0038] The substrate 21 has a rectangular shape extending in the X-axis direction. The electrodes 22 are formed on the surface of the substrate 21 on the positive side of the Z-axis near the end on the negative side of the Y-axis. Here, five electrodes 22 are lined up in the X-axis direction with a predetermined gap between them. The electrodes 23 are formed on the surface of the substrate 21 on the positive side of the Z-axis near the end on the positive side of the Y-axis. Here, five electrodes 23 are lined up in the X-axis direction with a predetermined gap between them. The size and pitch of the five electrodes 23 in the X-axis direction are the same as those of the five electrodes 15 shown in FIG. 1. The substrate 21 has a terminal (not shown) at the end on the positive side of the Y-axis. This terminal is connected to the electrodes 22 and 23 and is used to connect each of the electrodes 22 and 23 to an external detection circuit.
[0039] The multiple wires 30 are arranged so as to extend in the Y-axis direction. Here, 40 wires 30 are arranged. Each wire 30 is arranged so as to be tilted in the X-axis direction by a predetermined angle with respect to the Y-axis. As will be described later, the wire 30 is made up of a conductor line 31 and a dielectric 32 that covers the surface thereof (see FIGS. 5(a) and 5(b)).
[0040] Eight wires 30 constitute one wire structure ST. Here, five wire structures ST are lined up in the X-axis direction with a predetermined gap between them. The eight wires 30 included in one wire structure ST are connected at their ends to form a continuous piece. The eight wires 30 included in one wire structure ST cross each other in a mesh-like pattern in the X-Y plane. The end of the wire structure ST on the positive side of the Y-axis is connected to the electrode 22 using solder. At this time, the dielectric 32 is removed from the end of the wire 30, and the exposed conductor line 31 is soldered to the electrode 22.
[0041] The configuration of the wire structure ST will be described in more detail later with reference to Fig. 4. The configuration of the wires 30 will be described later with reference to Figs.
[0042] FIG. 3 is a plan view schematically showing the configuration of the structure 1c in the manufacturing process.
[0043] 2 is placed upside down on the negative side of the Z axis of the structure 1a in Fig. 1. As a result, the surface on the positive side of the Z axis of the substrate 21 abuts against the opposing surface 11a (the surface on the negative side of the Z axis) of the first base member 11, and the wire structure ST made up of wires 30 abuts against the conductive elastic bodies 13. Each wire 30 of the wire structure ST crosses the five conductive elastic bodies 13 diagonally and intersects these conductive elastic bodies 13.
[0044] In this state, the wires 30 of each wire structure ST are sewn to the opposing surface 11a of the first base member 11 with thread 40. The thread 40 is sewn by, for example, a sewing machine. As will be described later, the sewing machine forms pinholes 11c (see FIGS. 5(a) and 5(b)) at a predetermined pitch in the X-axis direction and forms seams 43 (see FIGS. 5(a) and 5(b)) in the pinholes 11c to sew the wires 30 to the first base member 11.
[0045] The stitching rows 40a of the thread 40 extend in the X-axis direction. In the stitching rows 40a, the thread 40 straddles all of the wires 30 and sews each wire 30 to the first base member 11. In FIG. 3 , six stitching rows 40a of the thread 40 are arranged on the first base member 11.
[0046] In a plan view, the stitching rows 40a of the four inner threads 40 are located in the gaps between two adjacent conductive elastic bodies 13 in the Y-axis direction, and the stitching rows 40a of the two outer threads 40 are located outside the two outer conductive elastic bodies 13 in the Y-axis direction. The wire 30 is movable in the Y-axis direction while sewn with the threads 40, and its movement in the X-axis direction is restricted by the threads 40. The threads 40 are made of chemical fibers, natural fibers, or a mixture thereof.
[0047] Furthermore, by covering structure 1a with structure 1b, electrode 15 on the first base member 11 side and electrode 23 on the substrate 21 side come into contact with each other. In this state, first base member 11 and substrate 21 are sewn together with thread 50 at the positions of electrodes 15, 23. As a result, electrodes 15, 23 are joined to each other.
[0048] FIG. 4 is a plan view showing the configuration of the wire structure ST.
[0049] In the wire structure ST, a plurality of wires 30 are arranged along a plurality of straight lines inclined with respect to the Y-axis direction, thereby forming a plurality of meshes. That is, the plurality of wires 30 are arranged non-parallel to the arrangement direction (Y-axis direction) of the conductive elastic bodies 13, thereby forming a mesh of the wire structure ST. The wires 30 are inclined in two directions, the positive direction of the X-axis and the negative direction of the X-axis, and the inclination angles of the two inclination directions are the same.
[0050] In the first embodiment, the ends of adjacent wires 30 in the Y-axis direction are connected to each other, thereby forming a continuous string of eight wires 30. In Fig. 4, the route from end 30a to end 30b when the eight wires 30 are arranged in a continuous string is indicated by a solid arrow. By arranging the eight wires 30 in a continuous string along this route, a mesh of the wire structure ST is formed.
[0051] Here, two wires 30 intersect at position P1 on the stitching row 40a. The positions P1 are aligned with a predetermined gap in the X-axis direction. The thread 40 is sewn to the first base member 11 so as to straddle the two intersecting wires 30 at each position P1. Furthermore, two wires 30 are close to each other at position P2 on the stitching row 40a. The positions P2 are aligned with a predetermined gap in the X-axis direction. The thread 40 is sewn to the first base member 11 so as to straddle the two close wires 30 at each position P2. At this time, a stitch 43 is formed between two adjacent positions P1, and a stitch 43 is formed between two adjacent positions P2. Multiple stitching rows 40a of threads 40 extending in the X-axis direction are formed with a predetermined gap in the Y-axis direction.
[0052] 5(a) and (b) are schematic diagrams showing cross sections of the structure 1c of FIG. 3 when cut along a plane parallel to the XZ plane at the positions of the thread 40 passing through positions P1 and P2, respectively.
[0053] 5(a) and 5(b), the wire 30 is composed of a conductor wire 31 and a dielectric 32 formed on the conductor wire 31. The dielectric 32 is formed on the outer periphery of the conductor wire 31 and covers the entire surface of the conductor wire 31.
[0054] The conductor wire 31 is a conductive, linear member. The conductor wire 31 is made of, for example, a conductive metal material. Alternatively, the conductor wire 31 may be made of a glass core wire with a conductive layer formed on its surface, or a resin core wire with a conductive layer formed on its surface. For example, the conductor wire 31 may be made of a valve metal such as aluminum (Al), titanium (Ti), tantalum (Ta), niobium (Nb), zirconium (Zr), or hafnium (Hf), or tungsten (W), molybdenum (Mo), copper (Cu), nickel (Ni), silver (Ag), or gold (Au). In the first embodiment, the conductor wire 31 is made of copper. The conductor wire 31 may also be a twisted wire made of twisted wires made of a conductive metal material.
[0055] The dielectric 32 has electrical insulating properties and is made of, for example, a resin material, a ceramic material, a metal oxide material, etc. The dielectric 32 may be at least one resin material selected from the group consisting of polypropylene resin, polyester resin (for example, polyethylene terephthalate resin), polyimide resin, polyphenylene sulfide resin, polyvinyl formal resin, polyurethane resin, polyamideimide resin, polyamide resin, etc., and may be Al. 2 O 3 and Ta 2 O 5 and the like.
[0056] The diameter of the conductor wire 31 may be, for example, 0.01 mm or more and 1.5 mm or less, or 0.05 mm or more and 0.8 mm or less. Such a configuration of the conductor wire 31 is preferable from the viewpoint of the strength and resistance of the conductor wire 31. The thickness of the dielectric 32 is preferably 5 nm or more and 100 μm or less, and can be appropriately selected depending on the design of the sensor sensitivity, etc.
[0057] 5(a) and 5(b), the thread 40 is made up of an upper thread 41 arranged along the upper surface (opposing surface 11a) of the first base member 11 and a lower thread 42 arranged along the lower surface (upper surface 11b) of the first base member 11. The upper thread 41 and the lower thread 42 intersect with each other at the position of the needle eye 11c that penetrates the first base member 11 in the Z-axis direction, and a seam 43 is formed at this intersection. The thread 40 is sewn to the first base member 11 along the X-axis direction so as to straddle positions P1 and P2 shown in FIG. 4. As a result, multiple seams 43 are lined up in the X-axis direction.
[0058] A stitch row 40a of the thread 40 is formed by a plurality of stitches 43 aligned in the X-axis direction and the thread 40 between adjacent stitches 43. As shown in FIG. 4 , a plurality of stitch rows 40a of the thread 40 are formed on the opposing surface 11a of the first base member 11 at a predetermined pitch in the Y-axis direction. Between adjacent stitches 43 on each stitch row 40a, the wire 30 is sewn to the first base member 11 by the thread 40. As shown in FIG. 5( a), at position P1, two intersecting wires 30 are sewn to the first base member 11 by the thread 40 between adjacent stitches 43. As shown in FIG. 5( b), at position P2, two approaching wires 30 are sewn to the first base member 11 by the thread 40 between adjacent stitches 43.
[0059] FIG. 6 is a perspective view schematically showing the configuration of the load sensor 1. As shown in FIG.
[0060] The load sensor 1 includes the structure 1c of FIG.
[0061] The second base member 61 is a flat plate-shaped member. The second base member 61 is disposed opposite the lower surface (opposing surface 11a) of the first base member 11. The second base member 61 has the same shape as the first base member 11 in a plan view. The thickness of the second base member 61 is constant. When the thickness of the second base member 61 is small, the second base member 61 may be called a sheet member or a film member.
[0062] The second base member 61 has insulating properties and is made of, for example, a non-conductive resin material or a non-conductive rubber material. The second base member 61 is made of, for example, a material that can be used for the above-mentioned first base member 11. The second base member 61 may also be made of a hard material that is not easily elastically deformed.
[0063] The second base member 61 is placed on the structure 1c in Fig. 3 from below (the negative side of the Z axis). This causes the wire 30 to come into contact with the opposing surface 61a (the surface on the positive side of the Z axis) of the second base member 61. Then, the outer periphery of the first base member 11 is connected to the second base member 61 with a thread (not shown). This fixes the first base member 11 to the second base member 61. In this way, the load sensor 1 is completed as shown in Fig. 6.
[0064] The load sensor 1 is used with the first base member 11 facing upward (positive side of the Z axis) and the second base member 61 facing downward (negative side of the Z axis). In this case, the upper surface 11b of the first base member 11 is the surface to which the load is applied, and the lower surface 61b of the second base member 61 is placed on the installation surface.
[0065] Here, the load sensor 1 has a plurality of element units A1 arranged in a matrix in a plan view. The load sensor 1 of FIG. 6 has a total of 25 element units A1 arranged in the X-axis direction and the Y-axis direction. One element unit A1 corresponds to a region including an intersection between one conductive elastic body 13 and one wire structure ST arranged below the conductive elastic body 13. That is, one element unit A1 includes the first base member 11, the conductor 12, the conductive elastic body 13, the wire structure ST, and the second base member 61 near the intersection. When the lower surface of the load sensor 1 (the lower surface 61b of the second base member 61) is placed on a predetermined installation surface and a load is applied to the upper surface of the load sensor 1 (the upper surface 11b of the first base member 11) that constitutes the element unit A1, the electrostatic capacitance between the conductive elastic body 13 and the conductor wire 31 changes, and the load is detected based on the electrostatic capacitance.
[0066] 7A and 7B are diagrams showing a schematic cross section of the conductive elastic body 13 and the wire 30 in the vicinity of the intersection when the conductive elastic body 13 and the wire 30 are cut along a plane parallel to the XZ plane at the intersection.
[0067] 7A shows a state in which no load is applied, and FIG. 7B shows a state in which a load is applied, in which the lower surface 61b of the second base member 61 on the negative side of the Z axis is placed on the installation surface.
[0068] As shown in Fig. 7(a), when no load is applied, the force acting between the conductive elastic body 13 and the wire 30 is almost zero. From this state, as shown in Fig. 7(b), when a load is applied downward to the upper surface 11b of the first base member 11, the conductive elastic body 13 is deformed by the wire 30. At this time, the wire 30 is brought closer to the conductive elastic body 13 so as to be wrapped in the conductive elastic body 13, and the contact area between the wire 30 and the conductive elastic body 13 increases. This changes the capacitance between the conductor wire 31 and the conductive elastic body 13. The potential reflecting this change in capacitance is then measured in the detection circuit, and the load is calculated.
[0069] 8 is a plan view schematically illustrating the internal configuration of the load sensor 1 when viewed in the negative direction of the Z axis. For convenience, only the outlines of the first base member 11, the conductive elastic body 13, and the substrate 21 are shown in FIG.
[0070] As described above, the load sensor 1 has element portions A1 formed in the regions of intersections between the conductive elastic body 13 and the wire structure ST, and a plurality of element portions A1 are arranged in a matrix. The electrodes 15, 22, and 23 are connected via the substrate 21 to a detection circuit (not shown) including a load detection circuit.
[0071] The detection circuit detects the capacitance value for each element A1 while switching between the conductive elastic bodies 13 and the wire structures ST corresponding to the element A1 to be detected. Specifically, the detection circuit applies a DC voltage via a resistor to the conductive elastic bodies 13 and the wire structures ST that intersect in the element A1 to be detected, and measures the voltage value at this intersection. The voltage value at the intersection rises with a time constant determined by the resistance and the capacitance at the intersection (the capacitance between the conductive elastic bodies 13 and the eight conductor lines 31 aligned in the X-axis direction).
[0072] The capacitance at the intersection point has a magnitude corresponding to the load applied to the intersection point. In other words, the contact area of the dielectric 32 with the conductive elastic body 13 changes depending on the load applied to the intersection point. The capacitance at the intersection point has a value corresponding to this contact area. The detection circuit measures the voltage value at the intersection point at a predetermined timing after a certain period of time has elapsed since the start of application of the DC voltage, and obtains the load of the element portion A1 corresponding to that intersection point based on the measured voltage value. In this way, the load on each element portion A1 is detected.
[0073] By increasing the number of wires 30 arranged on each element unit A1, the change in contact area when a load is applied increases. This increases the sensitivity of each element unit A1 and widens the dynamic range. However, on the other hand, increasing the number of wires 30 arranged on each element unit A1 narrows the spacing between the wires 30 in the X-axis direction, making it difficult to sew the wires 30 to the base member.
[0074] In the first embodiment, this problem is solved by arranging the wires 30 as described above. This point will be explained below in comparison with a comparative example.
[0075] FIG. 9A is a plan view schematically showing the intervals between stitches 43 of the thread 40 according to a comparative example.
[0076] In the comparative example, eight wires 30 are arranged in one element unit A1, similar to the first embodiment, in order to improve the sensitivity and dynamic range of the element unit A1. However, in the comparative example, the eight wires 30 each extend linearly parallel to the Y axis and are arranged with a predetermined gap in the X axis direction. In this case, since each wire 30 needs to be sewn with thread 40 between adjacent stitches 43, if the width of the element unit A1 in the X axis direction is w1, the pitch (pinhole pitch) w2 of the pinholes 11c in the comparative example is w1 / 8. Therefore, if the width w1 of the element unit A1 is 10 mm, the pinhole pitch w2 in the comparative example is 1.25 mm.
[0077] However, as described above, when the thread 40 is sewn onto the first base member 11 by a sewing machine, the minimum pitch of the needle holes 11c is generally about 2 mm due to the mechanical precision of the sewing machine. Therefore, when the wire 30 is arranged as shown in Figure 9(a), it becomes difficult to provide two needle holes 11c sandwiching one wire 30, and it becomes difficult to properly sew the wire 30 onto the first base member 11 as shown in Figure 9(a).
[0078] In contrast, in the first embodiment, as shown in FIG. 4, a plurality of wires 30 are arranged in the X-axis direction so that one wire 30 intersects another wire 30 at a position P1.
[0079] FIG. 9B is a plan view schematically illustrating the intervals between stitches 43 of the thread 40 according to the first embodiment.
[0080] In the first embodiment, as in the comparative example, one element portion A1 includes eight wires 30. However, in the first embodiment, unlike the comparative example, two wires 30 cross in the gap between two conductive elastic bodies 13. In the example of FIG. 9(b), there are four positions P1 where the wires 30 cross in the upper gap 13a, and five positions P1 where the wires 30 cross in the lower gap 13b. Therefore, when two wires 30 are sewn together at these positions, the pitch (needle hole pitch) w3 of the pinholes 11c is w1 / 4. If the width w1 of the element portion A1 is 10 mm, the pinhole pitch w3 in the first embodiment is 2.5 mm.
[0081] As described above, according to the first embodiment, the needle hole pitch w3 of the needle holes 11c in the X-axis direction passing through position P1 is greater than 2 mm, which is the minimum pitch of the needle holes 11c based on the mechanical accuracy of the sewing machine, and therefore, in the stitching row 40a passing through position P1, it is possible to provide two stitches 43 sandwiching the two intersecting wires 30. Therefore, in the stitching row 40a passing through position P1, it is possible to properly sew the wire 30 to the first base member 11.
[0082] At position P2 (see FIG. 4), the plurality of wires 30 are arranged in the X-axis direction so that one wire 30 is close to another wire 30. As a result, the number of positions P2 where the wires 30 are close to each other outside the two outermost conductive elastic bodies 13 in the Y-axis direction is four or five. Therefore, in this case as well, the needle hole pitch w3 is w1 / 4, and therefore the wires 30 can be properly sewn to the first base member 11 in the stitching row 40a that passes through position P2.
[0083] <Effects of First Embodiment> According to the first embodiment, the following effects are achieved.
[0084] At position P1 of the stitching row 40a, the plurality of wires 30 (conductor wires 31) that intersect can be sewn together to the first base member 11. In this case, the intervals between the positions (sewn-up positions) where the plurality of wires 30 (conductor wires 31) intersect are wider than the intervals when the plurality of wires 30 (conductor wires 31) are simply lined up as in the comparative example of FIG. 9( a). Generally, a sewing machine for sewing thread has a minimum needle hole pitch based on machine precision. Therefore, even if the plurality of lined up wires (conductor wires 31) cannot be sewn up one by one due to the relationship with the minimum needle hole pitch, the load sensor 1 of embodiment 1 allows each wire 30 (conductor wire 31) to be properly sewn up because the intervals between the stitched-up positions are wide as described above.
[0085] As shown in Fig. 3, the stitching row 40a is arranged in the gap between adjacent conductive elastic bodies 13 in a plan view (for example, the gaps 13a and 13b in Fig. 9(b)). This prevents the stitching row 40a from overlapping with the element portion A1, thereby suppressing the influence of the stitching row 40a on load detection. This allows the load to be detected with high accuracy.
[0086] 4, the wires 30 (conductor wires 31) are arranged along a plurality of straight lines inclined with respect to the arrangement direction (Y-axis direction) of the conductive elastic bodies 13 in a plan view, forming a plurality of meshes. This makes it easier to align the vertices of the meshes, i.e., the positions P1 where two wires 30 (conductor wires 31) intersect, in straight lines at a predetermined pitch. This makes it easy to sew the wires 30 (conductor wires 31) to the first base member 11.
[0087] 4, the wires 30 (conductor wires 31) are connected to each other at their ends to form a continuous wire, which makes it easier to arrange the wires 30 (conductor wires 31) than when the wires 30 (conductor wires 31) are arranged individually.
[0088] The pitch of the stitches 43 on the stitch row 40a is 2 mm or more. Generally, the minimum needle hole pitch of a sewing machine is about 2 mm due to machine precision. Even if the needle hole pitch of the sewing machine can only be set as small as about 2 mm, multiple wires 30 (conductor wires 31) can be sewn together between adjacent stitches with a pitch of 2 mm or more. Therefore, each wire 30 (conductor wire 31) can be sewn in properly.
[0089] 8, a plurality of pairs of a wire structure ST consisting of a plurality of conductive elastic bodies 13 and a plurality of wires 30 (conductor wires 31) are arranged in a direction (X-axis direction) intersecting the arrangement direction (Y-axis direction) of the conductive elastic bodies 13. This allows the number of element portions A1 to be increased, and loads to be detected over a wider range.
[0090] 5(a) and 5(b), the dielectric 32 is disposed so as to cover the surface of the conductor wire 31. According to this configuration, the dielectric 32 can be disposed between the conductive elastic body 13 and the conductor wire 31 simply by covering the surface of the conductor wire 31 with the dielectric 32.
[0091] <Modification 1 of Embodiment 1> In embodiment 1, as shown in FIG. 4 , the wire structure ST is composed of wires 30 that are non-parallel to the arrangement direction (Y-axis direction) of the conductive elastic bodies 13, but it is not necessary that all of the wires 30 are non-parallel to the Y-axis direction, and some of the wires 30 or parts of the wires 30 may be parallel to the Y-axis direction.
[0092] FIG. 10 is a plan view showing the configuration of a wire structure ST according to a first modification of the first embodiment.
[0093] In this modified example, similarly to the first embodiment, the wire structure ST has a plurality of meshes formed by a plurality of linearly extending wires 30. However, in this modified example, each wire 30 extending from the positive side of the Y axis to the negative side of the Y axis has a portion parallel to the Y axis direction and a portion non-parallel to the Y axis direction. The inclination direction of the wire 30 in the portion non-parallel to the Y axis direction has two kinds of directions, the positive direction of the X axis and the negative direction of the X axis, and the inclination angles of the two kinds of directions are the same.
[0094] In this modification, the ends of adjacent wires 30 in the Y-axis direction are connected to each other, thereby forming a continuous string of eight wires 30. In Fig. 10, the route from end 30a to end 30b when the eight wires 30 are arranged in a continuous string is indicated by a solid arrow.
[0095] 5(a), at position P1 in this modified example, two intersecting wires 30 are sandwiched between two adjacent stitches 43, and these two wires 30 are sewn to the first base member 11 by the thread 40. At position P2 in the stitching row 40a in modified example 2, two approaching wires 30 are sandwiched between two adjacent stitches 43, and these two wires 30 are sewn to the first base member 11 by the thread 40, as in the configuration shown in FIG.
[0096] As described above, in Modification 1 of Embodiment 1, similarly to Embodiment 1, multiple conductor wires 31 that intersect at position P1 of the stitching row 40a can be sewn together to the first base member 11. Therefore, the intervals between the stitching positions can be widened, and each conductor wire 31 can be sewn appropriately.
[0097] <Modification 2 of Embodiment 1> In Embodiment 1, as shown in FIG. 4, the wire structure ST is configured by wires 30 extending linearly, but it is not necessary that all of the wires 30 extend linearly, and some of the wires 30 or a part of the wires 30 may extend in a curved shape.
[0098] FIG. 11 is a plan view showing the configuration of a wire structure ST according to a second modification of the first embodiment.
[0099] In this modified example, multiple meandering wires 30 are arranged in the wire structure ST to form multiple meshes. In this modified example, the ends of adjacent wires 30 are connected to each other at the ends in the Y-axis direction, forming a continuous string of eight wires 30. In Fig. 11, the route from end 30a to end 30b when the eight wires 30 are arranged in a continuous string is indicated by solid arrows.
[0100] As described above, in Modification 2 of Embodiment 1, similarly to Embodiment 1, multiple conductor wires 31 that intersect at position P1 of the stitching row 40a can be sewn together to the first base member 11. Therefore, the intervals between the stitching positions can be widened, and each conductor wire 31 can be sewn appropriately.
[0101] <Modification 3 of Embodiment 1> In embodiment 1, as shown in Figure 4, the ends of adjacent wires 30 are connected to each other at the ends in the Y-axis direction, making the eight wires 30 continuous, but this is not limited to this, and each wire 30 may be separated from each other.
[0102] FIG. 12 is a plan view showing the configuration of a wire structure ST according to a third modification of the first embodiment.
[0103] 4, the wire structure ST of this modified example is not configured by a continuous wire 30. That is, in this modified example, eight wires 30 that are not parallel to the Y-axis direction are arranged independently of each other. The shape of the mesh in a plan view of this modified example is the same as that of the first embodiment.
[0104] In addition, when the multiple wires 30 are arranged independently as in this modified example, it becomes necessary to arrange the multiple wires 30 individually when assembling the load sensor 1. Therefore, it is easier to arrange the multiple wires 30 when the multiple wires 30 are configured as a continuous piece as in the first embodiment.
[0105] <Embodiment 2> In embodiment 1, two wires 30 cross each other in the gap between adjacent conductive elastic bodies 13, but multiple wires 30 may be arranged so that two wires 30 are close to each other in the gap between adjacent conductive elastic bodies 13. The configuration of embodiment 2 is the same as embodiment 1 except for the wire structure ST.
[0106] FIG. 13 is a plan view showing the configuration of a wire structure ST according to the second embodiment.
[0107] The wire structure ST of the second embodiment has a wave shape in which the plurality of wires 30 meander in the direction of the stitching row 40a (the X-axis direction). The amplitude directions of adjacent wires 30 are opposite to each other, but the amplitudes of adjacent wires 30 are the same. In the second embodiment, the ends of adjacent wires 30 are connected to each other, thereby forming a continuous wire 30. In Fig. 13, the route from end 30a to end 30b when eight wires 30 are arranged in a continuous manner is indicated by a solid arrow.
[0108] Here, at position P2 on the stitching row 40a, two wires 30 are close to each other. The positions P2 are lined up with a predetermined gap in the X-axis direction. The thread 40 is sewn to the first base member 11 so as to straddle the two wires 30 that are close to each other at each position P2. At this time, a stitch 43 is formed between two adjacent positions P2. Multiple stitching rows 40a of the thread 40 extending in the X-axis direction are formed with a predetermined gap in the Y-axis direction.
[0109] Also, at position P2 in embodiment 2, similar to the configuration shown in Figure 5 (b), two approaching wires 30 are sandwiched between two adjacent stitches 43, and these two wires 30 are sewn to the first base member 11 by thread 40.
[0110] FIG. 14 is a plan view schematically showing the intervals between stitches 43 of the thread 40 according to the second embodiment.
[0111] In the second embodiment, as in the first embodiment, the element portion A1 includes eight wires 30. In the first modification, two wires 30 are close to each other at position P2. As a result, in the upper gap 13a between the two conductive elastic bodies 13, there are four positions P2, and in the lower gap 13b, there are five positions P2. Therefore, the pitch (needle hole pitch) w3 of the pinholes 11c is w1 / 4, as in the first embodiment. If the width w1 of the element portion A1 is 10 mm, the pinhole pitch w3 in this embodiment is 2.5 mm.
[0112] In this way, also in the second embodiment, the needle hole pitch w3 of the needle holes 11c in the X-axis direction passing through position P2 is greater than 2 mm, which is the minimum pitch of the needle holes 11c based on the mechanical accuracy of the sewing machine, so that in the stitching row 40a passing through position P2, it is possible to provide two stitches 43 sandwiching two approaching wires 30. Therefore, in the stitching row 40a passing through position P2, it is possible to properly sew the wire 30 to the first base member 11.
[0113] As described above, according to the second embodiment, similarly to the first embodiment, a plurality of wires 30 (conductor wires 31) that are close to each other at position P2 of the stitching row 40a can be sewn together to the first base member 11. Therefore, the intervals between the stitching positions can be widened, and each wire 30 (conductor wire 31) can be sewn appropriately.
[0114] 13, the wires 30 (conductor wires 31) have a wave-like shape that meanders in the direction of the stitching row 40a. This allows the wires 30 (conductor wires 31) to be arranged so that they do not overlap at the stitching row 40a, thereby preventing the wires 30 from rubbing against each other when a load is applied. This prevents damage to the dielectric 32 covering the conductor wires 31 and the occurrence of a short circuit between the conductive elastic body 13 and the conductor wires 31.
[0115] <Modification 1 of Embodiment 2> In Embodiment 2, as shown in FIG. 13 , the wire structure ST is configured so that the curved meandering wires 30 approach each other at position P2, but the wire structure ST may also be configured so that the straight meandering wires 30 approach each other at position P2.
[0116] FIG. 15 is a plan view showing the configuration of a wire structure ST according to a first modification of the second embodiment.
[0117] In this modified example, similar to the second embodiment, the plurality of wires 30 have a shape that meanders in the direction of the stitching rows 40a (X-axis direction). However, in this modified example, each wire 30 has a linear shape that has a linear portion that is non-parallel to the Y-axis direction. The inclination direction of the wire 30 in the portion that is non-parallel to the Y-axis direction has two types: the positive X-axis direction and the negative X-axis direction, and the inclination angle of the two types of inclination directions is the same.
[0118] In this modification, the ends of adjacent wires 30 in the Y-axis direction are connected to each other, thereby forming a continuous string of eight wires 30. In Fig. 15, the route from end 30a to end 30b when the eight wires 30 are arranged in a continuous string is indicated by a solid arrow.
[0119] Also, at position P2 in this modified example, similar to the configuration shown in Figure 5 (b), two approaching wires 30 are sandwiched between two adjacent stitches 43, and these two wires 30 are sewn to the first base member 11 by thread 40.
[0120] As described above, in Modification 1 of Embodiment 2, similarly to Embodiment 2, a plurality of conductor wires 31 that are close to each other at position P2 of the stitching row 40a can be sewn together to the first base member 11. Therefore, the intervals between the stitching positions can be widened, and each conductor wire 31 can be sewn appropriately.
[0121] 15, the plurality of wires 30 (conductor wires 31) have a shape that meanders in the direction of the stitching row 40a. This allows the plurality of wires 30 (conductor wires 31) to be arranged so that they do not overlap at the stitching row 40a, thereby preventing the wires 30 from rubbing against each other when a load is applied. This prevents damage to the dielectric 32 covering the conductor wires 31 and the occurrence of a short circuit between the conductive elastic body 13 and the conductor wires 31.
[0122] <Modification 2 of Embodiment 2> In Embodiment 2, as shown in FIG. 13 , the ends of adjacent wires 30 are connected to each other at the ends in the Y-axis direction, thereby forming a continuous string of eight wires 30, but each wire 30 may also be separated from each other.
[0123] FIG. 16 is a plan view showing the configuration of a wire structure ST according to a second modification of the second embodiment.
[0124] 13, the wire structure ST of this modified example is not configured by a continuous wire 30. That is, in this modified example, eight wires 30 meandering in the X-axis direction are arranged independently. The shape of this modified example in a plan view is the same as that of the second embodiment.
[0125] <Modification 3 of Embodiment 2> In Embodiment 1, the plurality of wires 30 are arranged so that two wires 30 cross each other in the gap between adjacent conductive elastic bodies 13, and in Embodiment 2, the plurality of wires 30 are arranged so that two wires 30 approach each other in the gap between adjacent conductive elastic bodies 13. However, this is not limiting, and two wires 30 may cross or approach each other in each gap between adjacent conductive elastic bodies 13.
[0126] FIG. 17 is a plan view showing the configuration of a wire structure ST according to a third modification of the second embodiment.
[0127] In this modified example, the eight wires 30 extend in the Y-axis direction while meandering in the X-axis direction. As in the first and second embodiments, each stitching row 40a is provided at a position where it does not overlap with the conductive elastic body 13. Referring to Fig. 17, in the second and fourth stitching rows 40a from the Y-axis positive side, a position P1 is provided where two wires 30 cross, and in the third and fifth stitching rows 40a from the Y-axis positive side, a position P2 is provided where two wires 30 approach each other.
[0128] In this modification, the ends of adjacent wires 30 in the Y-axis direction are connected to each other, thereby forming a continuous string of eight wires 30. In Fig. 17, the route from end 30a to end 30b when the eight wires 30 are arranged in a continuous string is indicated by a solid arrow.
[0129] <Other Modifications> In the above embodiment and modifications, each wire 30 is configured to have either a straight or curved shape, but it may have both straight and curved portions. Furthermore, in one wire structure ST, some wires 30 may be configured to be straight and other wires 30 may be configured to be curved.
[0130] In the above-described first embodiment, first and third modifications of the first embodiment, and first modification of the second embodiment, there are two types of inclination directions of the wires 30 that are not parallel to the Y-axis direction, and the inclination angles of the two types of inclination directions are the same, but this is not limited to this, and the inclination angles of the two types of inclination directions do not have to be the same. Also, in the above-described second modification of the first embodiment, the second embodiment, and first to third modifications of the second embodiment, the amplitudes of adjacent wires 30 are the same, but this is not limited to this, and the amplitudes of adjacent wires 30 do not have to be the same.
[0131] In the above embodiment and modified example, the position where the wire 30 crosses or approaches is a position where it does not overlap the conductive elastic body 13 in a plan view, but this is not limiting and the position may be a position where it overlaps the conductive elastic body 13 in a plan view. In this case, the wire 30 crosses or approaches at a position where it overlaps the conductive elastic body 13, and the wire 30 is sewn at this position by the thread 40. Therefore, in order to suppress the effect of the stitching row 40a on load detection, it is preferable that the position where the wire 30 crosses or approaches is a position where it does not overlap the conductive elastic body 13, as described above.
[0132] In the above embodiment and modified example, the conductive elastic body 13 is disposed on the facing surface 11 a of the first base member 11, but this is not limiting and the conductive elastic body 13 may be disposed on the facing surface 61 a of the second base member 61. Furthermore, the conductive elastic body 13 may be disposed on both the facing surface 11 a of the first base member 11 and the facing surface 61 a of the second base member 61.
[0133] In the above embodiment and modified example, the thread 40 is sewn to the first base member 11 , but this is not limiting and the thread 40 may be sewn to the second base member 61 .
[0134] In the above embodiment and modified examples, the dielectric 32 is disposed so as to cover the entire circumference of the conductor wire 31, but the dielectric 32 may be disposed so as to cover at least the area of the surface of the conductor wire 31 where the contact area changes depending on the load. Furthermore, the dielectric 32 is made of one type of material in the thickness direction, but may have a structure in which two or more types of materials are laminated in the thickness direction.
[0135] In the above embodiment and modified example, the dielectric 32 is disposed on the surface of the conductor wire 31, but the dielectric 32 that determines the capacitance between the conductor wire 31 and the conductive elastic body 13 may be disposed between the conductor wire 31 and the conductive elastic body 13. For example, as shown in Fig. 18, the dielectric 32 may be disposed on the surface of the conductive elastic body 13. In this case, the dielectric 32 is made of an elastically deformable material so that the contact area with the conductor wire 31 changes in response to a load. For example, the dielectric 32 is made of a material having the same elastic modulus as the conductive elastic body 13.
[0136] In the above embodiment and modified example, five wire structures ST are arranged and eight wires 30 are arranged in one element portion A1, but the number of wire structures ST and the number of wires 30 included in one element portion A1 are not limited to this. For example, the number of wire structures ST may be 1 to 4 or 6 or more, and the number of wires 30 included in one element portion A1 may be 1 to 7 or 9 or more.
[0137] In the above embodiment and modified example, five conductive elastic bodies 13 are arranged, but the number of conductive elastic bodies 13 arranged in the load sensor 1 is not limited to this. For example, the number of conductive elastic bodies 13 may be 1 to 4, or 6 or more.
[0138] In the above embodiments and modified examples, the method of placing the conductive elastic body 13 on the opposing surface 11a of the first base member 11 is not necessarily limited to printing, but may be other methods such as gluing foil.
[0139] In the above-described embodiment and modified examples, the wire structure ST extends in a direction parallel to the arrangement direction (Y-axis direction) of the conductive elastic bodies 13, but it may extend in a direction non-parallel to the arrangement direction of the conductive elastic bodies 13. For example, the wire structure ST and the conductive elastic bodies 13 may cross each other in diagonal directions.
[0140] In the above embodiments and modified examples, the width of the conductive elastic body 13 does not necessarily have to be constant; for example, the width of the conductive elastic body 13 may be narrower in the range between the element parts A1 in the direction in which the conductive elastic body 13 extends (X-axis direction).
[0141] In the above-described embodiment and modified examples, the conductor 12 may be omitted, and the wiring 14 may be connected to the conductive elastic body 13 .
[0142] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical ideas set forth in the claims.
[0143] REFERENCE SIGNS LIST 1 load sensor 11 first base member 11a opposing surface 12 conductor (conductive elastic body) 13 conductive elastic body 13a, 13b gap 31 conductor wire 32 dielectric body 40 thread 40a stitch row 43 stitch 61 second base member 61a opposing surface
Claims
a second base member disposed opposite said first base member; a plurality of conductive elastic bodies disposed in a row on opposing surfaces of at least one of said first base member and said second base member; a plurality of conductor wires disposed so as to intersect said plurality of conductive elastic bodies; a dielectric disposed between said conductive elastic bodies and said conductor wires; and a thread that sews said plurality of conductor wires to said first base member or said second base member by a row of stitches extending in a direction intersecting the arrangement direction of said plurality of conductive elastic bodies, wherein said plurality of conductor wires are disposed so that one of said conductor wires intersects or comes close to another of said conductor wires at the position of said row of stitches, and said thread is sewn to said first base member or said second base member so as to straddle said one conductor wire and said other conductor wires that intersect or come close to each other.
2. A load sensor according to claim 1, wherein the stitching rows are arranged in gaps between adjacent conductive elastic bodies in a plan view.
3. A load sensor according to claim 1 or 2, characterized in that the plurality of conductor wires are arranged along a plurality of straight lines inclined with respect to the arrangement direction in a plan view, thereby forming a plurality of meshes.
4. A load sensor according to claim 1 or 2, wherein the plurality of conductor wires have a wave shape that meanders in the direction of the stitching rows.
5. A load sensor according to any one of claims 1 to 4, characterized in that the ends of the plurality of conductor wires are connected to each other to form a continuous structure.
6. A load sensor according to any one of claims 1 to 5, characterized in that the pitch of the stitches on the stitch row is 2 mm or more.
7. A load sensor according to any one of claims 1 to 6, characterized in that a plurality of pairs of the conductive elastic bodies and the conductor wires are arranged in a direction intersecting the arrangement direction.
8. A load sensor according to any one of claims 1 to 7, characterized in that the dielectric is disposed so as to cover the surface of the conductor wire.