Load Sensor

Abstract

This load sensor comprises: a flat plate-shaped base member (11); a plurality of conductive elastic bodies (12) that are positioned so as to extend in a first direction, on an upper surface (11a) of the base member (11); at least one conductive member (conductor line (20)) that extends in a second direction and crosses the plurality of conductive elastic bodies (12); a dielectric body that is positioned between the plurality of conductive elastic bodies (12) and the conductive member; and a plurality of wirings (13) that are respectively connected to the plurality of conductive elastic bodies (12), and are positioned so as to extend in the second direction, on the upper surface (11a) of the base member (11). The wirings (13) are positioned in locations that do not overlap with the conductive member (conductor line (20)), and are provided with insulation (insulating bodies (14)) at least in the range where each overlaps with the conductive elastic bodies (12) other than the respective conductive elastic body (12) to which each is connected.

Description

[Technical Field]

[0001] The present invention relates to a load sensor that detects an externally applied load based on a change in capacitance. [Background technology]

[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) including a plurality of first electrodes made of a conductive elastic body, a plurality of second electrodes made of linear conductive members, and a dielectric covering the surfaces of the second electrodes. The plurality of first electrodes and the plurality of second electrodes are arranged so as to intersect with each other in a plan view.

[0004] In this configuration, when the load applied to each intersection of the first electrode and the second electrode increases, the contact area between the first electrode and the dielectric increases at each intersection, and the capacitance between the first electrode and the second electrode increases accordingly. Therefore, by detecting the value of the capacitance between the first electrode and the second electrode for each intersection, the load applied to each intersection can be detected. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 079995 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above configuration, a connector electrically connected to the plurality of first electrodes; 2 The first electrode and the second electrode are electrically connected to the connectors, which are individually arranged at different positions. The connector connected to the first electrode is arranged in the direction in which the first electrode extends, and the connector connected to the second electrode is arranged in the direction in which the second electrode extends. This increases the size of the load sensor, and the outer periphery where the connectors are arranged becomes a dead zone where the load cannot be detected.

[0007] In view of the above, an object of the present invention is to provide a load sensor that can reduce the size in a plan view and that can reduce the dead zone that occurs in the outer periphery. [Means for solving the problem]

[0008] A main aspect of the present invention relates to a load sensor. The load sensor according to this aspect includes a flat base member and a sensor element disposed on an upper surface of the base member so as to extend in a first direction. , arranged in a second direction intersecting the first direction A plurality of conductive elastic bodies; The aforementioned The plurality of conductive elastic bodies extend in a second direction. Top of to overlap At least one Linear a conductive member; a dielectric member disposed between the plurality of conductive elastic bodies and the conductive member; and a dielectric member disposed between the plurality of conductive elastic bodies and the conductive member. One end and a plurality of wirings connected to the base member and arranged on the top surface of the base member so as to extend in the second direction. Multiple The wiring is In the range of the first direction in which the plurality of conductive elastic bodies are arranged, is disposed at a position not overlapping the conductive member, contact Other than the conductive elastic body to be connected other overlapping the conductive elastic body The wiring overlaps at least one other conductive elastic body. The area is insulated The other conductive elastic body is overlapped on the upper surface of the insulating layer. , The other ends of the plurality of wirings and one end of the conductive member are arranged at one end of the base member adjacent in the second direction to the range in which the plurality of conductive elastic bodies are arranged. .

[0009] In the load sensor according to this aspect, the conductive member and the wiring extend in the same direction, so that one end of the conductive member and one end of the wiring can be arranged in the same region, which allows the size of the load sensor to be reduced compared to when these regions are different, and also reduces the dead zone that occurs in the outer periphery. [Effects of the Invention]

[0010] As described above, according to the present invention, it is possible to provide a load sensor that can reduce the size in a plan view and reduce the dead zone that occurs in the outer periphery.

[0011] 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. [Brief explanation of the drawings]

[0012] [Figure 1] Fig. 1(a) is a perspective view schematically showing the structure of the upper surface of a lower base member according to embodiment 1. Fig. 1(b) is a perspective view schematically showing a state in which conductor wires are installed on the lower base member according to embodiment 1. [Figure 2] Fig. 2(a) is a perspective view showing a state in which a circuit board is installed in the structure of Fig. 1(b) according to embodiment 1. Fig. 2(b) is a perspective view showing a state in which an upper base member is installed in the structure of Fig. 2(a) according to embodiment 1. [Figure 3] 3(a) and 3(b) are cross-sectional views schematically showing the periphery of the conductor wire according to the first embodiment, as viewed in the negative direction of the X-axis. [Figure 4] 4(a) to 4(d) are diagrams showing steps of forming a conductive elastic body, wiring, an insulator, and a conductor on the upper surface of a base member according to the first embodiment. [Figure 5]Fig. 5(a) is a plan view schematically showing the inside of the load sensor seen from above according to embodiment 1. Fig. 5(b) is a plan view schematically showing the inside of the load sensor seen from above according to a comparative example. [Figure 6] FIG. 6 is a diagram showing a state in which a plurality of load sensors are arranged in the Y-axis direction according to the first embodiment. [Figure 7] Fig. 7(a) is a perspective view showing the configuration of a structure according to embodiment 2. Fig. 7(b) is a perspective view showing the structure of the lower surface of the upper base member according to embodiment 2. [Figure 8] FIG. 8 is a diagram showing a state in which an upper base member is placed on the top surface of a lower base member according to the second embodiment. [Figure 9] 9(a) and 9(b) are cross-sectional views schematically showing the periphery of a conductor wire of a load sensor according to the second embodiment. [Figure 10] Fig. 10(a) is a perspective view showing the configuration of a structure according to embodiment 3. Fig. 10(b) is a perspective view showing the structure of the lower surface of the upper base member according to embodiment 3. [Figure 11] Fig. 11(a) is a perspective view showing the structure of Fig. 10(b) turned upside down and placed on the structure of Fig. 10(a) according to embodiment 3. Fig. 11(b) is a side view showing an enlarged view of the ends of opposing conductors according to embodiment 3. Fig. 11(c) is a side view showing the state in which the peripheries of the opposing conductors in the state of Fig. 11(b) have been sewn together with thread. [Figure 12] 12(a) and 12(b) are cross-sectional views schematically showing the periphery of a conductive member according to a modified example, as viewed in the negative direction of the X axis.

[0013] However, the drawings are for illustrative purposes only and do not limit the scope of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] 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.

[0015] Examples of management systems include inventory management systems, driver monitoring systems, coaching management systems, security management systems, and nursing care / childcare management systems.

[0016] 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.

[0017] 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 (for example, grip force, grip position, and pedal force). Also, a load sensor provided in the vehicle seat monitors the load distribution of the driver on the vehicle seat while seated (for example, center of gravity position). This makes it possible to provide feedback on the driver's driving state (drowsiness, psychological state, etc.).

[0018] 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.

[0019] 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.

[0020] In a caregiving and childcare management system, for example, load sensors installed on bedding and toilet seats monitor the weight distribution of 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 or toilet seat and prevent falls or trips.

[0021] 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, smartwatches, wireless earphones, touch panels, electronic pens, penlights, luminous clothing, musical instruments, etc. In electronic devices, a load sensor is provided in the input unit that receives input from the user.

[0022] 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.

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, each drawing has X, Y, and Z axes which are orthogonal to each other. The Z axis direction is the height direction of the load sensor 1.

[0024] <Embodiment 1> FIG. 1(a) is a perspective view schematically showing a base member 11, a conductive elastic body 12, wiring 13, an insulator 14, and a conductor 15 placed on the upper surface 11a (the surface on the positive side of the Z axis) of the base member 11.

[0025] The base member 11 is an elastic, insulating, flat-plate member. The base member 11 has a rectangular shape in a plan view. The thickness of the base member 11 is constant. When the thickness of the base member 11 is small, the base member 11 is sometimes called a sheet member or a film member. The base member 11 is made of a non-conductive resin material or a non-conductive rubber material.

[0026] The resin material used for the base member 11 is at least one resin material selected from the group consisting of, for example, styrene-based resins, silicone-based resins (such as polydimethylpolysiloxane (PDMS)), acrylic-based resins, rotaxane-based resins, and urethane-based resins. The rubber material used for the base member 11 is at least one rubber material selected from the group consisting of, for example, 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 conductive elastic bodies 12 are arranged on the upper surface 11a (the surface on the positive side of the Z axis) of the base member 11. In FIG. 1(a), five conductive elastic bodies 12 are arranged on the upper surface 11a of the base member 11. The conductive elastic bodies 12 are conductive members having elasticity. Each conductive elastic body 12 has a strip shape that is long in the Y axis direction. The conductive elastic bodies 12 are arranged to extend in a first direction (Y axis direction). In other words, the long sides of the conductive elastic bodies 12 are parallel to the Y axis. The five conductive elastic bodies 12 have the same width, length and thickness. A predetermined gap is provided between adjacent conductive elastic bodies 12.

[0028] The conductive elastic body 12 is formed on the upper surface 11a of the base member 11 by a printing method such as screen printing, gravure printing, flexographic printing, offset printing, or gravure offset printing. These printing methods make it possible to form the conductive elastic body 12 with a thickness of about 0.001 mm to 0.5 mm on the upper surface 11a of the base member 11. However, the method for forming the conductive elastic body 12 is not limited to the printing method.

[0029] The conductive elastic body 12 is made of a resin material with a conductive filler dispersed therein, or a rubber material with a conductive filler dispersed therein.

[0030] The resin material used for the conductive elastic body 12 is, like the resin material used for the above-described base member 11, 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 conductive elastic body 12 is, like the rubber material used for the above-described base member 11, 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.

[0031] The conductive filler used in the conductive elastic body 12 may be, for example, a metal material such as Au (gold), Ag (silver), Cu (copper), C (carbon), ZnO (zinc oxide), In2O3 (indium (III) oxide), or SnO2 (tin (IV) oxide), or a PEDOT:PSS (i.e., poly (The conductive filler is at least one material selected from the group consisting of conductive polymer materials such as a composite of 3,4-ethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS), metal-coated organic fibers, metal wires (in a fibrous state), etc. In the first embodiment, the conductive filler constituting the conductive elastic body 12 is carbon (C).

[0032] The wirings 13 are arranged on the upper surface 11a of the base member 11. The number of wirings 13 is the same as the number of conductive elastic bodies 12. In Fig. 1(a), five wirings 13 are arranged on the upper surface 11a of the base member 11. Each wiring 13 is arranged to extend in the second direction (X-axis direction).

[0033] The five wirings 13 are connected to the five conductive elastic bodies 12, respectively. The five wirings 13 and the five conductive elastic bodies 12 are connected one-to-one. Here, the wiring 13 furthest on the Y-axis positive side is connected to the conductive elastic body 12 furthest on the X-axis negative side, and the wiring 13 furthest on the Y-axis negative side is connected to the conductive elastic body 12 furthest on the X-axis positive side. The second, third, and fourth wirings from the Y-axis positive side are connected to the second, third, and fourth conductive elastic bodies 12 from the X-axis negative side, respectively.

[0034] The wiring 13 is composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein. The same material as the conductive elastomer 12 may be used as the resin material or rubber material constituting the wiring 13. As the conductive filler constituting the wiring 13, a material having excellent conductivity may be used from among the materials exemplified above as the conductive filler of the conductive elastomer 12. In the first embodiment, the conductive filler constituting the wiring 13 is Ag (silver). The wiring 13 is formed on the upper surface 11a of the base member 11 by the printing method described above.

[0035] The wiring 13 is insulated in the area where it overlaps with conductive elastic bodies 12 other than the conductive elastic body 12 to be connected. That is, an insulator 14 is formed covering the wiring 13 in the area of ​​the longitudinal wiring 13 that overlaps with conductive elastic bodies 12 other than the conductive elastic body 12 to be connected. In this way, the insulator 14 is interposed between the wiring 13 and the conductive elastic bodies 12 that are not to be connected. This allows the wiring 13 to be connected only to the conductive elastic bodies 12 to be connected. The insulator 14 is made of, for example, polyurethane resin. The insulator 14 is formed on the upper surface 11a of the base member 11 by the printing method described above.

[0036] The conductors 15 are arranged on the upper surface 11a of the base member 11. Here, five conductors 15 are arranged on the upper surface 11a of the base member 11 so as to be covered by five conductive elastic bodies 12, respectively, and extend in the first direction. The conductors 15 are arranged over substantially the entire range of the conductive elastic bodies 12 in the first direction. In other words, the lengths of the conductive elastic bodies 12 and the conductors 15 in the Y-axis direction are substantially the same. The conductors 15 are arranged at substantially the middle position of the conductive elastic bodies 12 in the X-axis direction.

[0037] The conductor 15 is made of a material with lower resistance than the conductive elastomer 12. In the first embodiment, the conductor 15 is an elastic, conductive member. The conductor 15 is made of a resin material with a conductive filler dispersed therein, or a rubber material with a conductive filler dispersed therein. The same material as the conductive elastomer 12 may be used as the resin material or rubber material constituting the conductor 15. As the conductive filler constituting the conductor 15, a material with excellent conductivity may be used from among the materials exemplified above as the conductive filler of the conductive elastomer 12. In the first embodiment, the conductive filler constituting the conductor 15 is Ag (silver). The conductor 15 is formed on the upper surface 11a of the base member 11 by the printing method described above.

[0038] The wiring 13 is connected to the conductive elastic body 12 to be connected, as well as to the conductor 15 located at the position of the conductive elastic body 12 to be connected. In this way, by connecting the wiring 13 to the low-resistance conductor 15, it is possible to reduce the resistance value between each position in the Y-axis direction of the conductive elastic body 12 and the end of the wiring 13 on the negative side of the X-axis, compared to when the conductor 15 is omitted. This makes it possible to improve the detection sensitivity of the sensor unit A1 (see FIG. 5(a)) described below.

[0039] The width in the X-axis direction and the thickness in the Z-axis direction of the conductor 15 are several times smaller than those of the conductive elastic body 12. The thickness of the conductor 15 is on the order of several microns. Therefore, the elastic properties of the conductor 15 do not significantly affect the elastic properties of the conductive elastic body 12, and even if the conductor 15 contains a conductive filler that is more expensive than the conductive elastic body 12, the cost does not increase significantly.

[0040] In FIG. 1(a), the thicknesses of the conductive elastic body 12 and the conductive body 15 are exaggerated for the sake of convenience, but in reality, the thickness of the conductive elastic body 12 is at most several hundred microns. Conductor 15 The thickness of the structure is about several microns. The method for forming the structure of Fig. 1(a) will be described later with reference to Figs. 4(a) to 4(d).

[0041] FIG. 1(b) is a perspective view that schematically shows a state in which a conductor wire 20 is installed on a base member 11. As shown in FIG.

[0042] The conductor wires 20 are formed by bending a linear member at a middle position. In the first embodiment, five conductor wires 20 are arranged so as to extend in the second direction (X-axis direction). The five conductor wires 20 are arranged overlapping on the upper surfaces of the five conductive elastic bodies 12 so as to intersect with the five conductive elastic bodies 12, respectively.

[0043] In plan view, the four conductor lines 20 are arranged between adjacent wirings 13. In other words, the wirings 13 are arranged in the range between adjacent conductor lines 20. The wirings 13 and conductor lines 20 are arranged in positions where they do not overlap each other in plan view. Here, the conductor lines 20 are arranged in the middle between adjacent wirings 13, in other words, the wirings 13 are arranged in the middle between adjacent conductor lines 20. As will be described later, the conductor lines 20 are made up of a linear conductive member 21 and a dielectric 22 formed so as to cover the surface of the conductive member 21 (see FIGS. 3(a) and 3(b)).

[0044] FIG. 2(a) is a perspective view showing a state in which a circuit board 31 is installed in the structure of FIG. 1(b).

[0045] The circuit board 31 is disposed on the upper surface 11a of the base member 11 so as to be aligned with the conductive elastic body 12 on the negative side of the X axis. The circuit board 31 is disposed so as to cover the ends of the five wirings 13 and the five conductor wires 20 on the negative side of the X axis. On the lower surface (the surface on the negative side of the Z axis) of the circuit board 31, multiple electrodes are disposed at positions that overlap the ends of the five wirings 13 and the five conductor wires 20 on the negative side of the X axis. In the areas where the conductor wires 20 overlap with the electrodes on the circuit board 31, the coating of the dielectric 22 is omitted, and the conductive member 21 is exposed. The five conductor wires 20 are connected to the corresponding electrodes by soldering when the circuit board 31 is installed.

[0046] Furthermore, when the circuit board 31 is placed on the upper surface 11a of the base member 11, the five conductor wires 20 are placed on the base member 11 with threads 16. In the example shown in FIG. 2(a), 30 threads 16 are sewn to the base member 11 so as to straddle the conductor wires 20 at positions other than the positions where the conductive elastic body 12 and the conductor wires 20 overlap. The stitching at the U-shaped bent portions restricts longitudinal movement of the five conductor wires 20. The other portions of the five conductor wires 20 are loosely sewn with threads 16 so as to allow longitudinal movement. The threads 16 are made of synthetic fibers, natural fibers, or a mixture thereof.

[0047] The circuit board 31 is sewn to the base member 11 with thread 16. At this time, the thread 16 is firmly sewn so that the end of the wire 13 on the negative side of the X-axis is joined to the electrode on the underside of the circuit board 31 that overlaps it. As a result, the end of the wire 13 and the electrode are pressed together, and the wire 13 is electrically connected to the circuit board 31.

[0048] FIG. 2(b) is a perspective view showing a state in which a base member 41 is installed on the structure of FIG. 2(a).

[0049] The base member 41 has the same configuration as the base member 11. The base member 41 has the same size and shape as the base member 11 and is made of the same material as the base member 11. The base member 41 is placed on the upper surface of the structure of FIG. 2(a). Then, the outer periphery of the base member 41 is connected to the outer periphery of the base member 11 with a silicone rubber adhesive, thread, or the like. This fixes the base member 41 to the base member 11. In this way, the load sensor 1 is completed.

[0050] The load sensor 1 may be used in a state in which it is turned upside down from the state shown in Fig. 2. In this case, the base member 41 does not necessarily have to be made of the same material as the base member 11, and may be made of, for example, a hard material that is not easily elastically deformed.

[0051] 3(a) and 3(b) are cross-sectional views schematically showing the periphery of the conductor wire 20 when the load sensor 1 in FIG. 2(b) is viewed in the negative direction of the X-axis. Fig. 3(a) shows a state where no load is applied, and Fig. 3(b) shows a state where a load is applied.

[0052] 3(a) and 3(b), the conductor wire 20 is composed of a conductive member 21 and a dielectric 22 formed so as to cover the surface of the conductive member 21. The conductive member 21 is a conductive wire material.

[0053] The conductive member 21 is made of, for example, a conductive metal material. Alternatively, the conductive member 21 may be made of a core wire made of glass and a conductive layer formed on the surface thereof, or a core wire made of resin and a conductive layer formed on the surface thereof. The conductive member 21 may also be a twisted wire formed by twisting wires made of a conductive metal material. In the first embodiment, the conductive member 21 is made of copper. The dielectric 22 has electrical insulation properties and is made of, for example, a resin material, a ceramic material, a metal oxide material, or the like.

[0054] Other examples of the conductive member 21 that can be used include valve metals such as titanium (Ti), tantalum (Ta), niobium (Nb), zirconium (Zr), and hafnium (Hf), as well as tungsten (W), molybdenum (Mo), aluminum (Al), nickel (Ni), silver (Ag), and gold (Au). The diameter of the conductive member 21 may be, for example, 10 μm to 1500 μm, or 50 μm to 800 μm. This configuration of the conductive member 21 is preferable from the viewpoint of the strength and resistance of the conductive member 21. The thickness of the dielectric 22 is preferably 5 nm to 100 μm, and can be appropriately selected depending on the design of the sensor sensitivity, etc.

[0055] 3(a), when no load is applied to the load sensor 1, the force acting between the conductive elastic body 12 and the conductor wire 20 is almost zero. From this state, as shown in FIG. 3(b), when an upward load is applied to the lower surface of the base member 11 and a downward load is applied to the upper surface of the base member 41, the conductive elastic body 12 is deformed by the conductor wire 20.

[0056] At this time, the conductor wire 20 is brought closer to the conductive elastic body 12 so as to be wrapped in the conductive elastic body 12, and the contact area between the conductor wire 20 and the conductive elastic body 12 increases. This causes a change in the capacitance between the conductive member 21 and the conductive elastic body 12. The load is calculated by detecting this change in capacitance.

[0057] 4(a) to 4(d) are diagrams showing the steps of forming the conductive elastic body 12, the wiring 13, the insulator 14, and the conductor 15 on the upper surface 11a of the base member 11. FIG.

[0058] As described above, the conductive elastic body 12, the wiring 13, the insulator 14 and the conductor 15 are formed by a printing method.

[0059] 4(a), five wires 13 are formed on the upper surface 11a of the base member 11 so as to extend in the X-axis direction. The ends of the five wires 13 on the negative side of the X-axis are located at the same position in the X-axis direction. The length of each wire 13 is set so that the end of each wire 13 on the positive side of the X-axis reaches the position of the conductor 15.

[0060] Next, as shown in FIG. 4(b), four insulators 14 are formed on the upper surface 11a of the base member 11 so as to cover the four wirings 13 on the negative side of the Y axis. The insulators 14 are formed in an area excluding both end portions of the wirings 13. Furthermore, as shown in FIG. 4(c), five conductors 15 are formed so as to extend in the Y axis direction. The conductors 15 overlap the ends of the corresponding wirings 13 where the insulators 14 are not formed. The five conductors 15 are all the same length. Furthermore, the positions of both ends of the five conductors 15 are the same in the Y axis direction. The five conductors 15 are formed at the same pitch in the X axis direction.

[0061] Five conductive elastic bodies 12 are formed on the upper surface 11a of the base member 11 so as to cover the five conductors 15, respectively. The widths of the five conductive elastic bodies 12 in the X-axis direction are the same, and the lengths of the five conductive elastic bodies 12 in the Y-axis direction are the same. Furthermore, the lengths of the conductive elastic bodies 12 in the Y-axis direction are approximately the same as the lengths of the conductors 15 in the Y-axis direction. X The conductor 15 is disposed at the middle position in the axial direction. A gap is provided between adjacent conductive elastic bodies 12.

[0062] 4(d), the end of each wiring 13 on the positive side of the X axis is joined to the conductive elastic body 12 and conductor 15 to be connected. An insulator 14 is formed in the area of ​​each wiring 13 that overlaps with conductive elastic bodies 12 and conductors 15 other than the conductive elastic body 12 and conductor 15 to be connected. This allows each wiring 13 to be connected only to the conductive elastic body 12 and conductor 15 to be connected.

[0063] Fig. 5(a) is a plan view schematically showing a state in which the inside of the load sensor 1 is seen through from above. For convenience, the thread 16 is not shown in Fig. 5(a).

[0064] The load sensor 1 has 25 sensor units A1 arranged in the X-axis and Y-axis directions. That is, rectangular areas where the conductive elastic bodies 12 and the conductor wires 20 intersect are set as sensor units A1 capable of detecting a load. The wiring 13 is arranged between the sensor units A1 adjacent to each other in the Y-axis direction.

[0065] FIG. 5(b) is a plan view schematically showing the inside of the load sensor 2 according to the comparative example as seen through from above.

[0066] In the comparative example, the wiring 17 connecting the conductive elastic body 12 and the circuit board 31 is drawn out to the positive side of the conductive elastic body 12 on the Y-axis. Therefore, a region for forming the wiring 17 is provided at the end on the positive side of the Y-axis in the base member 11, and the size in the Y-axis direction is larger by the width W1 of this region compared to the configuration of the first embodiment shown in Fig. 5(a). In the comparative example, the region of width W1 becomes a dead zone where a load cannot be detected.

[0067] In contrast to this, in the configuration of the first embodiment, the area for arranging the wiring 17 is omitted, so that the size in the Y-axis direction can be reduced, and the dead zone occurring in the outer periphery of the load sensor 1 can be reduced.

[0068] In the configuration of the comparative example, to reduce the size of the load sensor 2 in the Y-axis direction, it is necessary to make the width W1 as small as possible. In this case, the width of the wiring 17 must be reduced in accordance with the reduction in width W1. However, when the width of the wiring 17 is reduced, the resistance value of the wiring 17 increases. As a result, the load detection sensitivity of each sensor unit A1 decreases, and the load detection becomes more susceptible to the influence of noise.

[0069] In contrast, in the configuration of the first embodiment, the wiring 13 is arranged in a range that does not overlap the conductor wire 20, so the width of the wiring 13 can be set wide. This reduces the resistance value of the wiring 13. Therefore, the load detection sensitivity can be increased, and the load detection becomes less susceptible to the influence of noise.

[0070] 6 is a diagram showing a state in which a plurality of load sensors 1 are arranged side by side in the Y-axis direction. For convenience, the base member 41 is not shown in FIG.

[0071] As explained by comparing Figures 5(a) and (b), the configuration of embodiment 1 allows the size of the load sensor 1 in the Y-axis direction to be reduced. Therefore, when multiple load sensors 1 are arranged side by side in the Y-axis direction as shown in Figure 6, the width W2 of the dead zone where load cannot be detected can be effectively reduced. Therefore, it is possible to properly detect load over a wider range.

[0072] <Effects of the First Embodiment> According to the first embodiment, the following effects are achieved.

[0073] As shown in Fig. 5(a), the conductor wire 20 (conductive member 21) and the wiring 13 extend in the same direction, so one end of the conductor wire 20 (conductive member 21) and the end of the wiring 13 can be arranged in the same region. Therefore, compared to the case where these regions are different as in the comparative example of Fig. 5(b), the size of the load sensor 1 can be reduced, and the dead zone generated in the outer periphery of the load sensor 1 can be reduced.

[0074] 4(a) to 4(d), a plurality of conductors 15 having lower resistance than the conductive elastic bodies 12 are arranged on the upper surface 11a of the base member 11 so as to be covered by the plurality of conductive elastic bodies 12 and extend in the first direction (Y-axis direction). The wiring 13 is connected to the conductor 15 at the position of the conductive elastic body 12 to be connected. By connecting the wiring 13 to the low-resistance conductor 15 in this way, it is possible to reduce the resistance value between each position of the conductive elastic body 12 in the Y-axis direction and the end of the wiring 13 on the negative side of the X-axis, compared to when the conductor 15 is omitted. This makes it possible to improve the detection sensitivity of the sensor unit A1.

[0075] The plurality of conductors 15 are arranged over the entire range of the conductive elastic body 12 in the first direction (Y-axis direction). This makes it possible to reduce the resistance value of the combined structure of the conductive elastic body 12 and the conductors 15 over the entire length of the conductive elastic body 12. This makes it possible to increase the detection sensitivity of all sensor units A1 set in the load sensor 1.

[0076] 5(a), the conductor wire 20 (conductive member 21) is arranged in the range between adjacent wirings 13. This allows the wirings 13 and the conductor wire 20 (conductive member 21) to be smoothly arranged without overlapping each other. Furthermore, since the distance between the wirings 13 and the conductor wire 20 (conductive member 21) can be widened, the influence of the wirings 13 on load detection can be effectively suppressed.

[0077] 4(a) to 4(d), the conductive elastic body 12 and the wiring 13 are formed by printing on the upper surface 11a of the base member 11. This allows the conductive elastic body 12 and the wiring 13 to be easily arranged on the upper surface 11a of the base member 11.

[0078] 3(a) and 3(b), the dielectric 22 is disposed so as to cover the surface of the conductive member 21. According to this configuration, the dielectric 22 can be disposed between the conductive elastic body 12 and the conductive member 21 simply by covering the surface of the conductive member 21 with the dielectric 22.

[0079] <Embodiment 2> In the first embodiment, no conductive elastic body is disposed on the base member 41. In contrast to this, in the second embodiment, a conductive elastic body is disposed on the base member 41 as well as the base member 11.

[0080] FIG. 7(a) is a perspective view showing the configuration of a structure according to the second embodiment.

[0081] The structure in Fig. 7(a) corresponds to the structure in Fig. 2(a). However, in the structure in Fig. 7(a), five electrodes 32 are arranged in the Y-axis direction on the upper surface of the circuit board 31. The other configuration of the structure in Fig. 7(a) is the same as that of the structure in Fig. 2(a).

[0082] FIG. 7(b) is a perspective view showing the structure of the lower surface 41a of the base member 41 according to the second embodiment.

[0083] A conductive elastic body 42, wiring 43, insulator 44, and conductor 45 are arranged on the lower surface 41a of base member 41. The structure of FIG. 7(b) is a structure obtained by inverting the structure of FIG. 7(a) in the X-axis direction. The conductive elastic body 42, wiring 43, insulator 44, and conductor 45 are made of the same materials as the conductive elastic body 12, wiring 13, insulator 14, and conductor 15, respectively. The conductive elastic body 42, wiring 43, insulator 44, and conductor 45 are formed on the lower surface 41a of base member 41 by the same steps as those of FIGS. 4(a) to 4(d).

[0084] 7(b) is placed upside down on the top surface of the structure of Fig. 7(a). As a result, the five conductive elastic bodies 42 on the base member 41 side face the five conductive elastic bodies 12 on the base member 11 side, respectively, and the five conductor wires 20 are sandwiched between the five conductive elastic bodies 42 and the five conductive elastic bodies 12. In addition, the ends on the negative side of the X-axis of the five wires 43 on the base member 41 side overlap the five electrodes 32 on the top surface of the circuit board 31, respectively.

[0085] FIG. 8 is a diagram showing a state in which a base member 41 is placed on the upper surface of the base member 11. As shown in FIG.

[0086] In the state shown in FIG. 8, the base member 41 is sewn to the base member 11 with thread 18. At this time, the thread 18 is tightly sewn so that the end of the wiring 43 on the negative side of the X axis on the base member 41 side and the electrode 32 on the upper surface of the circuit board 31 that overlaps it are in close contact. This brings the end of the wiring 43 and the electrode 32 into pressure contact, and the wiring 43 is electrically connected to the circuit board 31. Furthermore, the outer periphery of the base member 41 is connected to the outer periphery of the base member 11 with a silicone rubber adhesive, thread, or the like, thereby fixing the base member 41 to the base member 11. In this way, the load sensor 1 is completed.

[0087] 9(a) and 9(b) are cross-sectional views schematically showing the periphery of the conductor wire 20 when the load sensor 1 in FIG. 8 is viewed in the negative direction of the X-axis. Fig. 9(a) shows a state where no load is applied, and Fig. 9(b) shows a state where a load is applied.

[0088] As shown in FIG. 9(b), in the load sensor 1 of the second embodiment, when a load is applied to the lower surface of the base member 11 and the upper surface of the base member 41, the conductive wire 20 causes the conductive elastic body 12 and the conductive elastic body 42 to deform.

[0089] At this time, the conductor wire 20 is wrapped around the conductive elastic bodies 12, 42. 、42 , and the contact area between the conductor wire 20 and the conductive elastic bodies 12, 42 increases. This changes the capacitance between the conductive member 21 and the conductive elastic bodies 12, 42. The load is calculated by detecting this change in capacitance.

[0090] <Effects of the Second Embodiment> As shown in Figures 7(a) to 9(b), the load sensor 1 of embodiment 2 comprises another base member 41 arranged opposite the upper surface 11a of the base member 11, a plurality of conductive elastic bodies 42 (other conductive elastic bodies) arranged on the lower surface 41a of the other base member 41 so as to face the plurality of conductive elastic bodies 12, respectively, and a dielectric 22 arranged between the plurality of conductive elastic bodies 42 (other conductive elastic bodies) and the plurality of conductive members 21.

[0091] According to this configuration, 9 As shown in (b), not only the contact area between the conductor wire 20 and the conductive elastic body 12 but also the contact area between the conductor wire 20 and the conductive elastic body 42 changes depending on the load, so the change in contact area when a load is applied is greater than in the cases of (a) and (b) in Figure 3. This increases the load detection sensitivity of the load sensor 1.

[0092] Also, in this configuration, similarly to the first embodiment, the size of the load sensor 1 in the Y-axis direction can be reduced, and the dead zone occurring in the outer periphery of the load sensor 1 can be reduced.

[0093] <Embodiment 3> In the above-described second embodiment, the conductive elastic body 42 on the base member 41 side is connected to the circuit board 31 by joining the wiring 43 and the electrode 32. In contrast, in the third embodiment, the wiring 43 and the insulator 44 on the base member 41 side are omitted.

[0094] FIG. 10(a) is a perspective view showing the configuration of a structure according to the third embodiment.

[0095] In the structure of Fig. 10(a), the end portion on the negative side of the Y-axis of the conductor 15 protrudes in the negative direction of the Y-axis from the edge on the negative side of the Y-axis of the conductive elastic body 12. The other configuration of the structure of Fig. 10(a) is similar to that of the structure of Fig. 2(a). In the structure of Fig. 10(a), the electrode 32 (see Fig. 7(a)) is not arranged on the upper surface of the circuit board 31.

[0096] FIG. 10(b) is a perspective view showing the structure of the lower surface 41a of the base member 41 according to the third embodiment.

[0097] In the third embodiment, the wiring 43 and the insulator 44 are not formed on the lower surface 41a of the base member 41. That is, in the third embodiment, the wiring 43 and the insulator 44 are omitted from the configuration of Fig. 7(b). Also, in the third embodiment, the end of the conductor 45 on the negative side of the Y axis protrudes in the negative direction of the Y axis from the edge of the conductive elastic body 42 on the negative side of the Y axis.

[0098] FIG. 11(a) is a perspective view showing the structure of FIG. 10(b) turned upside down and superimposed on the structure of FIG. 10(a).

[0099] 11(a), the five conductive elastic bodies 42 on the base member 41 side face the five conductive elastic bodies 12 on the base member 11 side, respectively, and the five conductor wires 20 are sandwiched between the five conductive elastic bodies 42 and the five conductive elastic bodies 12. Furthermore, the Y-axis negative side end of the conductor 15 on the base member 11 side faces the Y-axis negative side end of the conductor 45 on the base member 41 side in the Z-axis direction.

[0100] FIG. 11(b) is an enlarged side view showing the ends of the conductors 15 and 45 facing each other.

[0101] 11(b), for the sake of convenience, the distance D1 between the ends of the conductors 15 and 45 is shown larger than it actually is. In reality, the thickness of the conductive elastic bodies 12 and 42 is small, so the distance D1 is much smaller.

[0102] 11(b), the opposing positions of the conductors 15, 45 at the ends of the base members 11, 41 on the Y-axis negative side are tightly sewn together with thread 51. As a result, as shown in FIG. 11(c), the base members 11, 41 approach each other at this sewn position, and the conductors 15, 45 are joined. By joining the conductors 15, 45 in this manner, the conductor 45 on the base member 41 side is electrically connected to the conductor 15 on the base member 11 side. As a result, the conductor 45 on the base member 41 side is connected to the circuit board 31 via the conductor 15 and wiring 13 on the base member 11 side.

[0103] <Effects of the Third Embodiment> In the configuration of the third embodiment, similarly to the first embodiment, the change in the contact area when a load is applied is greater than in the cases of Figures 3(a) and 3(b), thereby improving the load detection sensitivity of the load sensor 1.

[0104] Also, in this configuration, similarly to the first embodiment, the size of the load sensor 1 in the Y-axis direction can be reduced, and the dead zone occurring in the outer periphery of the load sensor 1 can be reduced.

[0105] Furthermore, the configuration of embodiment 3 includes a connection structure for electrically connecting the opposing conductive elastic bodies 12, 42, in which the conductors 15, 45 protrude from the edges of the conductive elastic bodies 12, 42 to face each other, and a structure in which the opposing portions of the conductors 15, 45 are joined by thread 51. This makes it possible to omit the wiring 43 and insulator 44 from the configuration of Fig. 7(b), thereby simplifying the configuration and reducing costs.

[0106] However, the connection structure for electrically connecting the opposing conductive elastic bodies 12, 42 is not limited to this. For example, the conductors 15, 45 may be made to protrude from the edges of the conductive elastic bodies 12, 42, and these protruding portions may be joined with solder.

[0107] <Example of change> In the above-described first to third embodiments, the dielectric 22 is disposed so as to cover the entire periphery of the conductive member 21, but the dielectric 22 may be disposed so as to cover at least the area of ​​the surface of the conductive member 21 where the contact area changes depending on the load. Furthermore, the dielectric 22 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.

[0108] Furthermore, in the above-described first to third embodiments, the dielectric 22 is disposed on the surface of the conductive member 21, but a dielectric may also be disposed on the surface of the conductive elastic bodies 12 and 42. For example, in the configuration of the first embodiment, a dielectric 19 may be formed on the surface of the conductive elastic body 12 as shown in FIG. 12(a). In addition, in the configurations of the second and third embodiments, a dielectric 19 and 46 may be disposed on the surfaces of the conductive elastic bodies 12 and 42, respectively, as shown in FIG. 12(b). In these cases, the dielectrics 19 and 46 may be made of an elastically deformable material so that the contact area with the conductive member 21 changes depending on the load. For example, the dielectrics 19 and 46 are made of a material having the same elastic modulus as the conductive elastic bodies 12 and 42.

[0109] Furthermore, in the above-described first to third embodiments, the cross-sectional shape of the conductive member 21 is circular, but the cross-sectional shape of the conductive member 21 is not limited to circular, and may be other shapes such as elliptical or pseudo-circular.

[0110] Furthermore, in the above-described first to third embodiments, as shown in Fig. 1(b), five conductive elastic bodies 12, 42 and five conductor wires 20 (conductive members 21) are arranged in the load sensor 1, but the number of conductive elastic bodies 12, 42 and conductor wires 20 (conductive members 21) arranged in the load sensor 1 is not limited to this. For example, when the conductive elastic bodies 12 are arranged only on the base member 11 side as in the first embodiment, a plurality of conductive elastic bodies 12 may be arranged, and at least one conductor wire 20 (conductive member 21) may be arranged.

[0111] For example, the load sensor 1 may have a configuration in which one conductor wire 20 is overlapped with two conductive elastic bodies 12. In this case, too, the conductor wire 20 only needs to be positioned so as not to overlap with the two wirings 13 connected to the two conductive elastic bodies 12, respectively, in a plan view, and preferably be positioned at the middle of the gap between these two wirings 13.

[0112] Furthermore, in the above-described first to third embodiments, the conductor wire 20 is configured to be bent at a middle position, but the conductor wire 20 does not necessarily have to be bent, and two conductor wires may be connected to form a pair on the circuit board 31. Furthermore, one pair does not necessarily have to consist of two conductor wires; for example, three or more conductor wires may be connected to form a pair on the circuit board 31, or only one conductor wire may be placed at the position of the conductor wire 20 shown in the first and second embodiments. Furthermore, the shape of the conductor wire 20 does not necessarily have to be linear in plan view, and may be wavy.

[0113] Furthermore, in the above-described first to third embodiments, the conductor wire 20 (conductive member 21) is disposed at the intermediate position between the adjacent wirings 13, but the conductor wire 20 (conductive member 21) may be disposed at another position as long as it does not overlap the wirings 13 in a plan view. For example, the wirings 13 may be disposed between one conductor wire 20 (conductive member 21) bent into a U shape (between the straight portions extending in the X-axis direction).

[0114] 4(a) to 4(d), insulators 14 are arranged not only in the area where wiring 13 and conductive elastic body 12 overlap, but also in the area where wiring 13 and conductive elastic body 12 do not overlap (the area of ​​the gap between adjacent conductive elastic bodies 12), but insulators 14 do not have to be arranged in the area where wiring 13 and conductive elastic body 12 do not overlap. This also applies to embodiments 2 and 3.

[0115] In the first embodiment, the conductors 15 have the same length as shown in FIGS. 4(a) to 4(d), but the lengths of the conductors 15 may be different from each other. X The width in the axial direction is not limited to the widths shown in the above-described first to third embodiments. 、 For example, the conductor 15 X The width in the axial direction may be approximately the same as the width of the conductive elastic body 12. Furthermore, as long as there is no problem with load detection, the conductive body 15 does not necessarily have to be elastic. These points also apply to the conductive body 45.

[0116] If the resistance value of the conductive elastic body 12 does not pose a problem in detecting the load, the conductor 15 may be omitted and the wiring 13 may be connected only to the conductive elastic body 12. This also applies to the second and third embodiments.

[0117] Furthermore, the method for arranging the conductive elastic body 12, wiring 13, insulator 14, and conductor 15 on the upper surface 11a of the base member 11 is not necessarily limited to printing, and other methods such as bonding foil may be used. Furthermore, multiple wirings 13, 43 may be connected to one conductive elastic body 12, 42. Furthermore, the first direction and the second direction do not necessarily have to be perpendicular to each other.

[0118] 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. [Explanation of symbols]

[0119] 1 Load sensor 11 Base material 11a Top surface 12 Conductive elastic body 13 Wiring 14 Insulators 15 Conductors 19 Dielectrics 20 Conductor wire 21 Conductive material 22 Dielectrics 41 Base material (other base material) 41a Bottom surface 42 Conductive elastic body (other conductive elastic body) 43 Wiring 44 Insulator 45 Conductors 46 Dielectric 51 Thread (connecting structure)

Claims

1. a flat base member; a plurality of conductive elastic bodies arranged on an upper surface of the base member so as to extend in a first direction with substantially the same length and aligned in a second direction intersecting the first direction; at least one linear conductive member extending in the second direction and overlapping upper surfaces of the plurality of conductive elastic bodies; a dielectric disposed between the plurality of conductive elastic bodies and the conductive member; a plurality of wirings, one end of each of which is connected to the plurality of conductive elastic bodies, and which are arranged on the top surface of the base member so as to extend in the second direction; the plurality of wirings are arranged at positions that do not overlap the conductive member within a range in which the plurality of conductive elastic bodies are arranged in the first direction, The wiring that overlaps with the conductive elastic body other than the conductive elastic body to be connected is insulated at least in the area where it overlaps with the other conductive elastic body, and the other conductive elastic body overlaps on the upper surface of the insulation, the other ends of the plurality of wirings and one end of the conductive member are disposed at one end of the base member adjacent in the second direction to an area in which the plurality of conductive elastic bodies are disposed; A load sensor characterized by:

2. The load sensor according to claim 1, a plurality of conductors having a lower resistance than the conductive elastic body are respectively covered by the conductive elastic bodies and are disposed on the upper surface of the base member so as to extend in the first direction; The wiring is connected to the conductor at the position of the conductive elastic body to be connected. A load sensor characterized by:

3. The load sensor according to claim 2, the plurality of conductors are arranged over the entire range of the conductive elastic body in at least the first direction; A load sensor characterized by:

4. The load sensor according to any one of claims 1 to 3, The conductive member is disposed in a range between adjacent ones of the wirings. A load sensor characterized by:

5. The load sensor according to any one of claims 1 to 4, the conductive elastic body and the wiring are formed on the upper surface of the base member by printing; A load sensor characterized by:

6. The load sensor according to any one of claims 1 to 5, The dielectric is disposed so as to cover the surface of the conductive member. A load sensor characterized by:

7. The load sensor according to any one of claims 1 to 6, Another base member disposed opposite the upper surface of the base member; a plurality of other conductive elastic bodies arranged on the lower surface of the other base member so as to face the plurality of conductive elastic bodies, respectively; a dielectric disposed between the plurality of other conductive elastic bodies and the conductive member, A load sensor characterized by:

8. The load sensor according to claim 7, a connection structure for electrically connecting the conductive elastic body and the other conductive elastic body that face each other; A load sensor characterized by:

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