Load detection device

Abstract

A load detection device (2) is provided with a load sensor (1) and a sealing member (60) that encloses the load sensor (1). The sealing member (60) is provided with: a lower sealing member (62) on which the load sensor (1) is placed; an upper seal member (61) that covers the upper surface (11b) of the load sensor (1) and is joined to the lower seal member (62); and an air pressure adjustment structure for making the air pressure in a housing space (S) of the load sensor (1) formed by the lower seal member (62) and the upper seal member (61) substantially equal to the external air pressure.

Description

Technical Field

[0001] The present invention relates to a load detection device for detecting a load applied from the outside based on a change in electrostatic capacitance. Background Art

[0002] Load detection devices are widely used in the fields of industrial equipment, robots, and vehicles. In recent years, with the development of computer control technology and the improvement of appearance, electronic devices that use free-form surfaces in various ways, such as humanoid robots and automobile interior equipment, are being developed. Therefore, it is required to install high-performance load sensors for each free-form surface.

[0003] Patent Document 1 below describes a capacitance type load sensor, which includes a first conductive member having elasticity and a second conductive member in a linear shape covered with a dielectric. In this load sensor, when a load is applied, the contact area between the first conductive member and the dielectric increases, and the capacitance between the first conductive member and the second conductive member changes. Based on the change in the capacitance, the load applied to the load sensor is detected.

[0004] Prior art literature

[0005] Patent Literature

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

[0007] Problem that the invention aims to solve

[0008] In the load sensor having the above structure, the linear second conductive member covered by the dielectric is sandwiched between the substrate and the first conductive member, so a gap is generated between the substrate and the first conductive member. Therefore, water, oil, foreign matter, etc. easily enter the gap, thereby causing a problem that the characteristics of the load sensor are easily deteriorated.

[0009] Such a problem can be eliminated by sealing the load sensor airtightly with a sealing member. However, in this case, if the load sensor is sealed in a vacuum state, the air pressure in the space inside the sealing member is lower than the external air pressure, and the pressure generated by the air pressure difference is applied to the load sensor. Therefore, even though no load is applied, the load sensor still enters a state where it detects the load generated by the air pressure difference.

[0010] On the other hand, if the load sensor is hermetically sealed by the sealing member so that the air pressure in the space inside the sealing member is higher than the external air pressure, the applied load is pushed back by the sealing member. Therefore, the load sensor cannot accurately detect the load, and the detection accuracy of the load is reduced.

[0011] In view of the above problems, an object of the present invention is to provide a load detection device that can prevent the characteristics of a load sensor from being deteriorated due to moisture, oil, foreign matter, etc., and can accurately detect an applied load.

[0012] Solutions for solving problems

[0013] The main scheme of the present invention relates to a load detection device. The load detection device of this scheme includes a load sensor and a sealing member that encapsulates the load sensor. The load sensor includes: an upper substrate that has elasticity; a lower substrate that is arranged opposite to the upper substrate; at least one conductive elastic body that is formed on at least one of the opposite surfaces of the upper substrate and the opposite surfaces of the lower substrate; at least one linear conductive member that is arranged between the upper substrate and the lower substrate; and a dielectric that is formed on the periphery of the linear conductive member. The sealing member includes: a lower sealing member that carries the load sensor; an upper sealing member that covers the upper surface of the load sensor and is bonded to the lower sealing member; and an air pressure adjustment structure that is used to make the air pressure in the storage space of the load sensor formed by the lower sealing member and the upper sealing member approximately equal to the external air pressure.

[0014] According to the load detection device of this scheme, since the load sensor is enclosed in the sealing member, it is not easy for moisture, oil or foreign matter to intrude into the gap between the upper substrate and the lower substrate. Therefore, it is possible to prevent the characteristics of the load sensor from being deteriorated due to the intrusion of the above-mentioned moisture, oil or foreign matter. In addition, since the air pressure in the storage space of the load sensor is made roughly equal to the external air pressure by using the air pressure adjustment structure, it is possible to suppress the reduction of detection accuracy caused by the air pressure difference between the storage space and the outside. Therefore, the applied load can be accurately detected.

[0015] Effects of the Invention

[0016] As described above, according to the present invention, it is possible to provide a load detection device that can prevent the characteristics of a load sensor from being deteriorated due to moisture, oil, foreign matter, or the like, and can accurately detect an applied load.

[0017] The effects and meanings of the present invention will be further clarified by the description of the following embodiments. However, the following embodiments are merely examples of implementing the present invention, and the present invention is not limited to any of the contents described in the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 (a) is a perspective view schematically showing the upper substrate of Embodiment 1 and the conductive portion formed on the facing surface of the upper substrate. Figure 1 (b) schematically shows the embodiment 1. Figure 1 (a) is a perspective view of a structure in which a conductive elastic body is arranged.

[0019] Figure 2 (a) is a perspective view schematically showing the lower substrate, the conductors formed on the opposite surface of the lower substrate, the wiring, and the terminal portion according to the first embodiment. Figure 2 (b) schematically shows the embodiment 1. Figure 2 (a) is a perspective view showing a state where an insulating film is provided on a structure.

[0020] Figure 3 (a) schematically shows the embodiment 1. Figure 2 (b) is a perspective view of a structure in which a lead wire, a substrate, and a connector are arranged. Figure 3 (b) schematically shows the embodiment 1. Figure 3 The structure of (a) is provided with Figure 1 (b) is a three-dimensional diagram of the state of the structure.

[0021] Figure 4 (a) and Figure 4 (b) are views schematically showing a cross section of the element portion when the element portion according to the first embodiment is cut along a plane parallel to the YZ plane at the center position of the element portion in the Y-axis direction.

[0022] Figure 5 It is a plan view schematically showing the arrangement of various parts of the load sensor according to the first embodiment when viewed in the negative direction of the Z axis.

[0023] Figure 6 This is a schematic diagram showing an example of the potential of each part in the first embodiment.

[0024] Figure 7 (a) and Figure 7 (b) are a plan view and a cross-sectional view schematically showing the structure of the load detection device according to the first embodiment.

[0025] Figure 8 (a) and Figure 8 (b) are a plan view and a cross-sectional view schematically showing the structure of a load detection device according to a modification example of the first embodiment.

[0026] Fig. 9 (a) and Fig. 9 (b) are a plan view and a cross-sectional view schematically showing the structure of the load detection device according to the second embodiment.

[0027] Fig.10 (a) and Fig.10(b) are a plan view and a cross-sectional view schematically showing the structure of a load detection device according to a modified example of the second embodiment.

[0028] Fig.11 (a) and Fig.11 (b) are a plan view and a cross-sectional view schematically showing the structure of the load detection device according to the third embodiment.

[0029] Fig.12 (a) and Fig.12 (b) are a plan view and a cross-sectional view schematically showing the structure of a load detection device according to a modified example of the third embodiment.

[0030] Fig.13 (a) and Fig.13 (b) are a plan view and a cross-sectional view schematically showing the structure of the load detection device according to the fourth embodiment.

[0031] Fig.14 It is a plan view schematically showing the structure of a load detection device according to a modified example of the fourth embodiment.

[0032] Fig.15 It is a cross-sectional view schematically showing the structure of a load detection device according to a modified example of the fourth embodiment.

[0033] Fig.16 (a) is a cross-sectional view schematically showing the structure of a load detection device near a boundary according to a comparative example. Fig.16 (b) is a cross-sectional view schematically showing the structure of a load detection device near a boundary according to a modification of the fourth embodiment.

[0034] Fig.17 (a) is a cross-sectional view schematically showing a load detection device in a case where a conductive coating is applied to the outer surface of a sealing member according to a fifth embodiment. Fig.17 (b) is a cross-sectional view schematically showing the load detection device in the case where the sealing member is made of a conductive material according to the fifth embodiment.

[0035] Fig.18 It is a cross-sectional view schematically showing the structure of a load detection device according to another modified example.

[0036] However, the drawings are intended to be illustrative only and not limiting of the scope of the present invention. DETAILED DESCRIPTION

[0037] The load sensor of the present invention can be applied to a management system that performs processing according to an applied load or a load sensor of an electronic device.

[0038] Examples of the management system include an inventory management system, a driver monitoring system, a coaching management system, a safety management system, and a nursing and childcare management system.

[0039] In an inventory management system, for example, a load sensor provided on an inventory shelf is used to detect the load of stacked inventory, and the types and quantity of goods on the inventory shelf are detected. Thus, in stores, factories, warehouses, etc., inventory can be efficiently managed, and staff can be streamlined. In addition, a load sensor provided in a refrigerator is used to detect the load of food in the refrigerator, and the types and quantity or weight of food in the refrigerator are detected. Thus, a recipe using the food in the refrigerator can be automatically suggested.

[0040] In the driver monitoring system, for example, a load sensor provided in the steering device is used to monitor the load distribution of the driver relative to the steering device (e.g., gripping force, gripping position, pedaling force). In addition, a load sensor provided in the vehicle seat is used to monitor the load distribution of the driver relative to the vehicle seat when the driver is seated (e.g., center of gravity position). This can provide feedback on the driver's driving state (drowsiness, psychological state, etc.).

[0041] In the coaching management system, for example, load sensors provided on the soles of the shoes are used to monitor the load distribution on the soles of the feet, thereby making it possible to correct or guide the foot to an appropriate walking state or exercise state.

[0042] In the safety management system, for example, load sensors installed on the ground are used to detect the load distribution when a person passes by, and to detect the weight, stride, speed, shoe sole pattern, etc. Thus, by comparing the above detection information with the data, the person passing by can be verified.

[0043] In the nursing and childcare management system, for example, load sensors installed on bedding and toilet seats are used to monitor the load distribution of the human body relative to the bedding and toilet seats. Thus, based on the position of the bedding and toilet seats, it is possible to infer what action the person is trying to take, and prevent falls.

[0044] Examples of electronic devices include in-vehicle devices (car navigation systems, audio equipment, etc.), home appliances (electric kettles, IH induction cookers, etc.), smart phones, electronic paper, e-book readers, PC keyboards, game controllers, smart watches, wireless headphones, touch screens, electronic pens, pen-shaped lights, luminous clothing, musical instruments, etc. In electronic devices, a load sensor is provided at an input portion that receives input from a user.

[0045] The load sensor in the following embodiments is an electrostatic capacitance type load sensor typically provided in the load sensor of the management system or electronic equipment as described above. There are also cases where such a load sensor is called an "electrostatic capacitance type pressure sensitive sensor element", "capacitive pressure detection sensor element", "pressure sensitive switch element", etc. In addition, the load detection device in the following embodiments includes a load sensor and a sealing member encapsulating the load sensor. The load detection device is connected to an external detection circuit, and the load detection device and the detection circuit constitute a load detection system. The following embodiment is one embodiment of the present invention, and the present invention is not subject to any limitation of the following embodiments.

[0046] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings. For convenience, each drawing is annotated with mutually orthogonal X-axis, Y-axis, and Z-axis. The Z-axis direction is the height direction of the load sensor and the load detection device.

[0047] <Implementation method 1>

[0048] Figure 1 (a) is a perspective view schematically showing the upper substrate 11 and the conductive portion 12 formed on the facing surface 11 a (the surface on the negative side of the Z axis) of the upper substrate 11 .

[0049] The upper substrate 11 is an elastic insulating member. The upper substrate 11 is a plate-shaped member having flat planes on the positive side and the negative side of the Z axis. The planes on the positive side and the negative side of the Z axis of the upper substrate 11 are parallel to the XY plane. The thickness of the upper substrate 11 is, for example, about 0.1 mm to 1.2 mm. The elastic modulus of the upper substrate 11 is, for example, about 0.01 MPa to 10 MPa, and more specifically, about 1 MPa to 5 MPa.

[0050] The upper substrate 11 is made of a non-conductive resin material or a non-conductive rubber material. The resin material used for the upper substrate 11 is, for example, at least one resin material selected from the group consisting of styrene resins, silicone resins (e.g., polydimethylsiloxane (PDMS)), acrylic resins, rotaxane resins, and polyurethane resins. The rubber material used for the upper substrate 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, chloroether rubber, polyurethane rubber, and natural rubber.

[0051] The conductive portion 12 is formed on the opposite surface 11a of the upper substrate 11. Here, the three conductive portions 12 are arranged on the opposite surface 11a of the upper substrate 11 in a manner extending in the X-axis direction. The three conductive portions 12 are arranged in the Y-axis direction with a predetermined gap. The conductive portion 12 is made of a material having an impedance lower than that of the conductive elastic body 13 described later. The thickness of the conductive portion 12 is smaller than the thickness of the conductive elastic body 13 described later. In addition, the width of the conductive portion 12 in the Y-axis direction is smaller than the width of the conductive elastic body 13 described later.

[0052] Furthermore, the conductive portion 12 may be omitted. However, when the conductive portion 12 is provided with respect to the conductive elastic body 13 described later, the conductivity of the structure including the conductive elastic body 13 and the conductive portion 12 can be improved compared to the conductivity of the conductive elastic body 13 alone.

[0053] Figure 1 (b) is a schematic representation of Figure 1 (a) is a perspective view of a structure in which a conductive elastic body 13 is arranged.

[0054] The conductive elastic body 13 is formed on the opposite surface 11a of the upper substrate 11 so as to cover the conductive portion 12. The conductive elastic body 13 is formed on the opposite surface 11a so that the conductive portion 12 is located approximately in the middle of the conductive elastic body 13 in the Y-axis direction. Here, the three conductive elastic bodies 13 are arranged on the opposite surface 11a of the upper substrate 11 so as to extend in the X-axis direction. The three conductive elastic bodies 13 are arranged in the Y-axis direction with a predetermined gap.

[0055] The conductive elastic body 13 is a conductive member having elasticity. The conductive portion 12 and the conductive elastic body 13 formed so as to cover the conductive portion 12 are electrically connected. The conductive portion 12 and the conductive elastic body 13 are composed of a resin material and a conductive filler dispersed in the resin material, or a rubber material and a conductive filler dispersed in the rubber material.

[0056] Like the resin material used for the upper substrate 11, the resin material used for the conductive portion 12 and the conductive elastic body 13 is, for example, at least one resin material selected from the group consisting of styrene resins, silicone resins (polydimethylsiloxane (such as PDMS)), acrylic resins, rotaxane resins, and polyurethane resins. Like the rubber material used for the upper substrate 11, the rubber material used for the conductive portion 12 and the conductive elastic body 13 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, polyurethane rubber, and natural rubber.

[0057] The conductive filler constituting the conductive part 12 and the conductive elastomer 13 is, for example, at least one material selected from the group consisting of metal materials such as Au (gold), Ag (silver), Cu (copper), C (carbon), ZnO (zinc oxide), In2O3 (indium (III) oxide) and SnO2 (tin (IV) oxide), conductive polymer materials such as PEDOT:PSS (i.e., a composite composed of poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS)), metal-coated organic fibers, and conductive fibers such as metal wires (in fiber state).

[0058] In Embodiment 1, the conductive filler constituting the conductive portion 12 is Ag (silver), and the conductive filler constituting the conductive elastomer 13 is C (carbon). As a result, the conductivity of the conductive portion 12 is higher than that of the conductive elastomer 13. Generally speaking, materials with higher conductivity are expensive, but according to this structure, the conductive portion 12 with higher conductivity can be saved, so the cost of the conductive portion 12 can be suppressed to a low level. In addition, generally speaking, if the elastomer contains a material with higher conductivity, the elastic modulus increases (the elastomer itself becomes harder), but according to this structure, the conductive member 41 described later (see Figure 4 (a) Figure 4 Since the width of the conductive portion 12 in the Y-axis direction at the position (b)) is small, the elastic modulus of the structure including the conductive portion 12 and the conductive elastic body 13 can be maintained low. Therefore, the electrostatic capacitance can be smoothly changed according to the load.

[0059] In Embodiment 1, the elastic modulus of the conductive elastic body 13 is set to be the same as the elastic modulus of the upper substrate 11. In addition, the conductive portion 12 contains Ag (silver) as a conductive filler, and therefore, the elastic modulus of the conductive portion 12 is slightly higher than the elastic modulus of the conductive elastic body 13, for example, several MPa or more or tens of MPa or more.

[0060] The conductive part 12 and the conductive elastic body 13 are formed on the opposite surface 11a of the upper substrate 11 by printing methods such as screen printing, gravure printing, flexographic printing, offset printing, and gravure offset printing. Figure 1 After forming the conductive portion 12 as shown in (a), Figure 1 The conductive elastic body 13 is formed in a manner overlapping the conductive part 12 as shown in (b). According to the above printing method, the conductive part 12 and the conductive elastic body 13 can be formed with a thickness of about 0.001 mm to 0.5 mm on the opposite surface 11a of the upper substrate 11. However, the method for forming the conductive part 12 and the conductive elastic body 13 is not limited to the above printing method.

[0061] During the assembly described below, Figure 1The front and back sides of the structure shown in (b) are reversed. As a result, the surface of the upper substrate 11 on the positive side of the Z axis becomes the upper surface 11b.

[0062] Figure 2 (a) is a perspective view schematically showing the lower substrate 21 , the conductor 22 formed on the opposing surface 21 a (the surface on the positive side of the Z axis) of the lower substrate 21 , the wiring 23 , and the terminal portion 24 .

[0063] The lower substrate 21 is an insulating member. The lower substrate 21 is a plate-shaped member having flat planes on the positive side and the negative side of the Z axis, and the planes on the positive side and the negative side of the Z axis of the lower substrate 21 are parallel to the XY plane. As described later, the lower substrate 21 is arranged opposite to the upper substrate 11. The thickness of the lower substrate 21 is, for example, about 0.1 mm to 1.5 mm. The rigidity of the lower substrate 21 is relatively high, and the elastic modulus of the lower substrate 21 is above 30 MPa.

[0064] The lower substrate 21 is made of a non-conductive resin material. The resin material used for the lower substrate 21 is, for example, at least one resin material selected from the group consisting of polyurethane, polyethylene terephthalate, polyethylene, polycarbonate, and polyimide.

[0065] The conductor 22 and the wiring 23 are formed on the opposite surface 21a of the lower substrate 21. Here, the six conductors 22 extending in the Y-axis direction are arranged with a predetermined gap in the X-axis direction, and three groups (a pair of conductors 22) consisting of two adjacent conductors 22 are arranged in the X-axis direction. The wiring 23 extends from the end of the pair of conductors 22 on the negative side of the Y-axis. The adjacent pair of conductors 22 is connected at a predetermined position in the Y-axis direction, and the terminal portion 24 protrudes from the connection position in the positive direction of the X-axis. One terminal portion 24 is arranged for the pair of conductors 22. The three terminal portions 24 are respectively arranged at Figure 1 The relative positions of the three conductive elastic bodies 13 shown in (b).

[0066] A pair of conductors 22, wiring 23 connected to the pair of conductors 22, and a terminal portion 24 protruding from the pair of conductors 22 are integrally formed and electrically connected. The conductors 22, wiring 23, and terminal portion 24 are made of the same material as each other, and are made of a resin material and a conductive filler dispersed in the resin material, or a rubber material and a conductive filler dispersed in the rubber material, as in the above-mentioned conductive portion 12. In the first embodiment, the conductive filler constituting the conductors 22, wiring 23, and terminal portion 24 is Ag (silver).

[0067] The conductor 22, the wiring 23 and the terminal portion 24 are formed on the opposite surface 21a of the lower substrate 21 by printing methods such as screen printing, gravure printing, flexographic printing, offset printing and gravure offset printing. According to the above printing method, each part can be formed with a thickness of about 0.001 mm to 0.5 mm on the opposite surface 21a of the lower substrate 21. However, the forming method of each part is not limited to the above printing method.

[0068] Figure 2 (b) is a schematic representation of Figure 2 (a) is a perspective view of a structure in which an insulating film 31 is provided.

[0069] The insulating film 31 is an insulating member. The insulating film 31 is a sheet-like member parallel to the XY plane. The thickness of the insulating film 31 is, for example, 0.03 mm. The elastic modulus of the insulating film 31 is 30 MPa or more. The insulating film 31 is made of a non-conductive resin material. The resin material used for the insulating film 31 is, for example, at least one resin material selected from the group consisting of polyurethane, polyethylene terephthalate, polyethylene, polycarbonate, and polyimide.

[0070] The end of the wiring 23 on the negative side of the Y axis extends to the vicinity of the end of the lower substrate 21 on the negative side of the Y axis, and the insulating film 31 is not provided at the end of the lower substrate 21 on the negative side of the Y axis. Figure 2 A hole 31a is formed at a position corresponding to the end of the terminal portion 24 in the positive direction of the X axis, which passes through the insulating film 31 vertically. As described later, the hole 31a is used to connect the conductive elastic body 13 and the terminal portion 24.

[0071] Figure 3 (a) is a schematic representation of Figure 2 (b) is a perspective view of a structure in which the lead wire 40, the substrate 25, and the connectors 26 and 27 are arranged.

[0072] The wires 40 are arranged overlappingly on the upper surface of the insulating film 31. Here, the six wires 40 extending in the Y-axis direction are arranged with a predetermined gap in the X-axis direction, and three groups (a pair of wires 40) consisting of two adjacent wires 40 are arranged in the X-axis direction. Figure 2 The six conductors 22 shown in (a) are at the same position. The two pairs of conductors 40 are connected to each other in the external detection circuit of the later stage. In addition, the paired conductors 40 can also be connected together at the ends on the positive side of the Y axis.

[0073] The wire 40 includes a linear conductive member 41 and a dielectric 42 formed on the surface of the conductive member 41. The structure of the wire 40 will be described later. Figure 4 (a) Figure 4Each of the conductive wires 40 is provided on the lower substrate 21 by wires so as to be movable in the direction in which the conductive wires 40 extend (the Y-axis direction).

[0074] In such Figure 3 After the lead wire 40 is arranged as in (a), the substrate 25 is set on the upper surface of the end portion on the negative side of the Y axis of the lower substrate 21. On the upper surface of the substrate 25, the connectors 26 and 27 are arranged in the X-axis direction. When the substrate 25 is set, the wiring provided on the substrate 25 is connected to Figure 2 The end of the wiring 23 on the negative side of the Y axis shown in (b) and Figure 3 The end of the wire 40 shown in (a) on the negative side of the Y axis. Thus, the three wires 23 are connected to the predetermined terminals of the connector 26 via the wiring in the substrate 25, and the six wires 40 are connected to the predetermined terminals of the connector 27 via the wiring in the substrate 25. The connectors 26 and 27 are connected to an external detection circuit.

[0075] Figure 3 (b) is a schematic representation of Figure 3 The structure of (a) is provided with Figure 1 (b) is a three-dimensional diagram of the state of the structure.

[0076] make Figure 1 The structure (b) is flipped over on the front and back sides. Figure 3 Thus, the lead wire 40 is in contact with the conductive elastic body 13 disposed on the upper substrate 11 .

[0077] After that, the wire 51 is sewn to the upper surface 11b of the upper substrate 11 and the lower surface 21b of the lower substrate 21 through the hole 31a. At this time, the conductive elastic body 13 is located above the hole 31a, and the terminal portion 24 is located below the hole 31a. Therefore, by sewing the wire 51 to the upper surface 11b and the lower surface 21b, the conductive elastic body 13 and the terminal portion 24 can be crimped and electrically connected. The wire 51 is composed of chemical fiber, natural fiber, or mixed fiber of the above fibers, and is composed of a non-conductive material.

[0078] The upper substrate 11 is fixed to the lower substrate 21 by connecting the outer periphery of the upper substrate 11 to the lower substrate 21 with wires. Figure 3 As shown in (b), the load sensor 1 is completed.

[0079] The load sensor 1 is used with the upper substrate 11 facing upward (Z-axis positive side) and the lower substrate 21 facing downward (Z-axis negative side). In this case, the upper surface 11b of the upper substrate 11 becomes the surface to which the load is applied, and the lower surface 21b of the lower substrate 21 becomes the loading surface.

[0080] Here, a plurality of element portions A1 arranged in a matrix shape in a plan view are formed in the load cell 1. In Figure 3 In the example shown in (b) of, a total of nine element portions A1 arranged in the X-axis direction and the Y-axis direction are formed in the load cell 1. One element portion A1 corresponds to a region including the intersection of the conductive elastomer 13 and a pair of lead wires 40 disposed below the conductive elastomer 13. That is, one element portion A1 includes the upper substrate 11, the conductive portion 12, the conductive elastomer 13, the lead wire 40, and the lower substrate 21 near the intersection. When the lower surface (the lower surface 21b of the lower substrate 21) of the load cell 1 is provided on a predetermined installation surface and a load is applied to the upper surface (the upper surface 11b of the upper substrate 11) of the load cell 1 constituting the element portion A1, the electrostatic capacitance between the conductive elastomer 13 and the conductive member 41 in the lead wire 40 changes, and the load is detected based on this electrostatic capacitance.

[0081] Figure 4 In (a) of Figure 4 FIGS. (b) are diagrams schematically showing a cross section of the element portion A1 when cut by a plane parallel to the X-Z plane at the central position in the Y-axis direction of the element portion A1.

[0082] Figure 4 FIG. (a) shows a state where no load is applied, Figure 4 FIG. (b) shows a state where a load is applied. In Figure 4 In (a) of Figure 4 In FIG. (b), the lower surface 21b on the negative Z-axis side of the lower substrate 21 is provided on the installation surface.

[0083] As Figure 4 In (a) of Figure 4 As shown in FIGS. (b), the lead wire 40 is composed of a conductive member 41 and a dielectric 42 formed on the conductive member 41. The dielectric 42 is formed on the outer periphery of the conductive member 41 and covers the surface of the conductive member 41.

[0084] The conductive member 41 is a member having a linear shape. The conductive member 41 is made of, for example, a conductive metal material. In addition, the conductive member 41 may be composed of a core wire including glass and a conductive layer formed on the surface of the core wire, or may be composed of a core wire including resin and a conductive layer formed on the surface of the core wire, etc. For example, as the conductive member 41, rectifying action metals such as aluminum (Al), titanium (Ti), tantalum (Ta), niobium (Nb), zirconium (Zr), hafnium (Hf), tungsten (W), molybdenum (Mo), copper (Cu), nickel (Ni), silver (Ag), gold (Au), etc. can be used.

[0085] The dielectric 42 has insulating properties, and is made of, for example, a resin material, a ceramic material, a metal oxide material, etc. The dielectric 42 may be at least one resin material selected from the group consisting of polypropylene resin, polyester resin (e.g., polyethylene terephthalate resin), polyimide resin, polyphenylene sulfide resin, polyvinyl formal resin, polyurethane resin, polyamide-imide resin, polyamide resin, etc., or may be at least one metal oxide material selected from the group consisting of Al2O3 and Ta2O5, etc.

[0086] like Figure 4 As shown in (a), when no load is applied to the element portion A1, the force applied between the conductive elastic body 13 and the wire 40 and the force applied between the insulating film 31 and the wire 40 are substantially zero. Figure 4 When a load is applied downward relative to the upper surface 11 b of the element portion A1 as shown in (b), the conductive elastic body 13 , the conductive portion 12 , and the upper substrate 11 are deformed by the wire 40 .

[0087] like Figure 4 As shown in (b), when a load is applied, the wire 40 is surrounded by the conductive elastic body 13 and approaches the conductive elastic body 13, and the contact area between the wire 40 and the conductive elastic body 13 increases. As a result, the electrostatic capacitance between the conductive member 41 and the conductive elastic body 13 changes. In addition, by measuring the potential reflecting the change in the electrostatic capacitance in the element part A1 in the external circuit, the load applied to the element part A1 is calculated.

[0088] Figure 5 It is a plan view schematically showing the arrangement of each part of the load sensor 1 when viewed in the negative direction of the Z axis.

[0089] exist Figure 5 , for convenience, the layer including the upper substrate 11 and the conductive elastic body 13, the layer including the wire 40, the layer including the insulating film 31, and the layer including the lower substrate 21, the conductor 22, and the terminal portion 24 are shown in a row. The conductive elastic body 13 is shown in a state of penetrating the upper substrate 11.

[0090] As described above, nine element portions A1 arranged in a matrix are formed in the measurement region of the load sensor 1. The nine element portions A1 correspond to nine locations where the conductive elastic body 13 and the pair of conductive wires 40 intersect. Hereinafter, the nine element portions A1 are referred to as A11, A12, A13, A21, A22, A23, A31, A32, and A33.

[0091] The conductive elastic body 13 corresponding to the element parts A11 to A13 is connected to the terminal part 24 of the pair of conductors 22 connected to the negative side of the X axis via the hole 31a on the negative side of the X axis. Similarly, the conductive elastic body 13 corresponding to the element parts A21 to A23 is connected to the terminal part 24 connected to the pair of conductors 22 in the center via the hole 31a in the center. The conductive elastic body 13 corresponding to the element parts A31 to A33 is connected to the terminal part 24 connected to the pair of conductors 22 on the positive side of the X axis via the hole 31a on the positive side of the X axis. The external circuit sequentially changes the element parts as the detection object of the load at a predetermined time interval.

[0092] Figure 6 1 is a schematic diagram showing the potential of each part when the element part A22 is the detection target of the load. Figure 3 (b)) processes the sequence of detecting the load applied to the element portion A22 when the load is applied to the element portion A22.

[0093] The external circuit connects the conductive elastic body 13 in the center corresponding to the element part A22 to the ground end, and applies a constant voltage (Vcc) to the conductive member 41 in the pair of wires 40 corresponding to the element part A22. Specifically, the external circuit connects the conductive elastic body 13 in the center to the ground end by connecting the pair of conductors 22 in the center to the ground end. In addition, the external circuit applies a constant voltage (Vcc) to the conductive member 41 in the pair of wires 40 in the center. As a result, the potential of the conductive elastic body 13 in the center becomes the ground potential (GND), and the potential V1 of the conductive member 41 in the pair of wires 40 in the center gradually rises according to the time constant corresponding to the electrostatic capacitance of the element part A22.

[0094] Furthermore, the external circuit sets the potential of the conductive elastic body 13 and the potential of the conductive member 41 corresponding to the element portion other than the element portion A22 to be detected to the same potential V1 as the pair of conductive members 41 corresponding to the center of the element portion A22. Specifically, the external circuit sets the potential V1 for the pair of conductors 22 on the positive side of the X axis and the pair of conductors 22 on the negative side of the X axis, thereby setting the potential V1 for the conductive elastic body 13 on the positive side of the Y axis and the conductive elastic body 13 on the negative side of the Y axis. In addition, the external circuit sets the potential V1 for the conductive member 41 in the pair of wires 40 on the positive side of the X axis and the conductive member 41 in the pair of wires 40 on the negative side of the X axis.

[0095] The external circuit measures the potential V1 of the conductive member 41 corresponding to the element portion A22 of the detection object at a predetermined time after the constant voltage (Vcc) is applied. The external circuit calculates the electrostatic capacitance of the element portion A22 based on the measured potential V1. Furthermore, the external circuit obtains the load applied to the element portion A22 based on the calculated electrostatic capacitance.

[0096] When the load as described above is obtained, since the potential V1 or the ground potential (GND) is set for the conductor 22, the lower side of the wire 40 is electrically shielded by the conductor 22. Therefore, even if the electrostatic capacitance component approaches from the lower side of the wire 40, the error caused by the change of the potential V1 can be suppressed. In addition, since the potential V1 or the ground potential (GND) is set for the conductive elastic body 13, the upper side of the wire 40 is electrically shielded by the conductive elastic body 13. Therefore, even if the electrostatic capacitance component approaches from the upper side of the conductive elastic body 13, the error caused by the change of the potential V1 can be suppressed.

[0097] Furthermore, in the load sensor 1 as described above, Figure 4 (a) shows a structure in which the wire 40 is sandwiched between the conductive elastic body 13 and the lower substrate 21, so a gap is generated between the conductive elastic body 13 and the lower substrate 21. Therefore, moisture, oil or foreign matter can easily invade the gap, thereby easily deteriorating the characteristics of the load sensor 1. Such a problem can be solved by sealing the load sensor 1 airtightly with a sealing member. However, in this case, the difference between the air pressure of the space inside the sealing member and the external air pressure will cause the load detection accuracy to decrease.

[0098] In contrast, in Embodiment 1, as described below, load sensor 1 is enclosed in sealing member 60, and a structure is provided to suppress the air pressure difference between the inside and outside of sealing member 60. Thus, the load applied to load sensor 1 can be accurately detected.

[0099] Figure 7 (a) Figure 7 (b) are a plan view and a cross-sectional view schematically showing the structure of the load detection device 2, respectively. Figure 7 (b) is a diagram obtained by observing a cross section of the load detection device 2 cut along a YZ plane passing through the lead wire 40 on the negative side of the X axis, along the positive direction of the X axis.

[0100] like Figure 7 (a) Figure 7 As shown in (b) of FIG. 1 , the load detection device 2 includes a load sensor 1, a sealing member 60 that encloses the load sensor 1, and a cable 70. The sealing member 60 has a rectangular shape in a plan view. The cable 70 is composed of a plurality of cables and is connected to the connectors 26 and 27.

[0101] like Figure 7 As shown in FIG. 2( b ), the sealing member 60 includes an upper sealing member 61 that covers the upper surface of the load sensor 1 (the upper surface 11 b of the upper substrate 11 ) and a lower sealing member 62 on which the load sensor 1 is placed.

[0102] The upper sealing member 61 is configured to have low rigidity. Thus, by configuring the upper sealing member 61 to be flexible, it is possible to suppress the load applied from the load detection device 2 from spreading in the XY plane, and thus the applied load can be appropriately detected in the corresponding element portion A1. From such a viewpoint, it is preferred that the upper sealing member 61 is configured, for example, so that the moment of inertia of the section is less than 1 / 8, and the elastic modulus is less than 1 / 8 of the upper substrate 11. In addition, in the upper sealing member 61, the moment of inertia of the section may be greater than 1 / 8, and the elastic modulus may be greater than 1 / 8 of the upper substrate 11.

[0103] The upper sealing member 61 is made of a material having airtightness. The lower sealing member 62 is configured to have a higher rigidity than the upper sealing member 61 .

[0104] The upper sealing member 61 is made of a material with elasticity and insulation. The upper sealing member 61 is made of a resin material or a rubber material. The resin material used in the upper sealing member 61 is, for example, at least one resin material selected from the group including polyethylene terephthalate (PET), polyurethane resin (polyurethane sheet), styrene resin, silicone resin (such as polydimethylsiloxane (PDMS)), acrylic resin and rotaxane resin. The rubber material used in the upper sealing member 61 is at least one rubber material selected from the group including silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene-propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, chloroether rubber, polyurethane rubber and natural rubber.

[0105] The upper seal member 61 of the first embodiment is made of a polyurethane resin (polyurethane sheet), so that the material of the upper seal member 61 can be easily obtained and the cost of the upper seal member 61 can be reduced.

[0106] The lower sealing member 62 is made of the same material as the upper sealing member 61. That is, the lower sealing member 62 is made of a resin material or a rubber material. The resin material used by the lower sealing member 62 is, for example, at least one resin material selected from the group including polyethylene terephthalate (PET), polyurethane resin (polyurethane sheet), styrene resin, silicone resin (such as polydimethylsiloxane (PDMS)), acrylic resin and rotaxane resin. The rubber material used by the lower sealing member 62 is at least one rubber material selected from the group including silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene-propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, chloroether rubber, polyurethane rubber and natural rubber.

[0107] The lower seal member 62 of the first embodiment is made of polyethylene terephthalate (PET), so that the desired rigidity of the lower seal member 62 can be achieved and the cost of the lower seal member 62 can be reduced.

[0108] During assembly, the load sensor 1 is placed on the upper surface of the lower sealing member 62 , and the upper sealing member 61 is arranged on the upper surface 11 b of the load sensor 1 (the upper surface 11 b of the upper substrate 11 ) so as to be in close contact with the upper surface.

[0109] For example, in the case where the lower sealing member 62 is relatively hard as in the present embodiment, if the upper sealing member 61 is joined to the lower sealing member 62 without loosening, the rigidity of the lower sealing member 62 can be utilized to suppress the occurrence of looseness in the upper sealing member 61. Thus, the close fit between the upper sealing member 61 and the upper substrate 11 can be maintained. In addition, if the upper sealing member 61 is joined to the lower sealing member 62 without loosening while the peripheral portion of the lower sealing member 62 is slightly bent upward, the elastic restoring force of the lower sealing member 62 is utilized to generate a pulling force that pushes the upper sealing member 61 against the upper surface 11b of the upper substrate 11. Thus, the close fit between the upper sealing member 61 and the upper substrate 11 is further improved.

[0110] In addition, if static electricity is generated between the upper sealing member 61 and the upper substrate 11, the electrostatic capacitance cannot be accurately measured, resulting in reduced accuracy of load detection. In order to avoid this problem, it is preferred that the upper sealing member 61 and the upper substrate 11 are made of materials with a close triboelectric series. Thus, static electricity generated by friction between the upper sealing member 61 and the upper substrate 11 can be suppressed.

[0111] However, even if the upper sealing member 61 and the upper substrate 11 are made of materials with close triboelectric series, static electricity may be generated due to friction between the upper sealing member 61 and the upper substrate 11. If the triboelectric series of the two are far apart, static electricity is more likely to be generated. In order to prevent this problem, it is preferred that an antistatic treatment is applied to the joint surface of the upper sealing member 61 and the upper substrate 11. As an antistatic treatment, for example, a surface active layer may be formed on the inner surface of the upper sealing member 61 side.

[0112] When the cable 70 is connected to the connectors 26 and 27, the upper sealing member 61 and the lower sealing member 62 are joined so as to sandwich the cable 70. Specifically, as in Figure 7 As shown by the hatching in (a), the outer edge portion of the upper sealing member 61 and the outer edge portion of the lower sealing member 62 are bonded to each other by an adhesive. By joining the upper sealing member 61 and the lower sealing member 62 at the outer edge portion, a storage space S is formed inside the sealing member 60.

[0113] In addition, the cable 70 is not limited to passing through the overlapping position of the upper sealing member 61 and the lower sealing member 62, and can also be pulled out from the inside of the sealing member 60 to the outside through the hole provided in the upper sealing member 61 or the lower sealing member 62. In this case, the hole through which the cable 70 passes is sealed with an adhesive or the like.

[0114] Here, the lower sealing member 62 includes a mesh structure that blocks the entry and exit of moisture and oil and allows the entry and exit of gas as a ventilation structure that ventilates the storage space S to the outside. The mesh structure has micropores that penetrate the lower sealing member 62. The lower sealing member 62 of embodiment 1 is composed of a raw material including a mesh structure, and as such a raw material, for example, TEMISH (registered trademark) can be cited. The lower sealing member 62 includes a mesh structure, whereby liquids and solids cannot pass through the lower sealing member 62, and only gases can pass through the lower sealing member 62. Thus, the air pressure in the storage space S is roughly equal to the external air pressure.

[0115] In addition, the lower sealing member 62 is not limited to the case where the entire lower sealing member 62 is composed of a raw material including a mesh structure, and the lower sealing member 62 may be partially composed of a raw material including a mesh structure. For example, the lower sealing member 62 may be mainly composed of an airtight raw material, and the opening formed in the part of the raw material is blocked by the raw material including a mesh structure. Alternatively, the lower sealing member 62 may be formed by joining an airtight raw material and a raw material including a mesh structure.

[0116] Thereby, the load detection device 2 is completed. Thereafter, the cable 70 is connected to an external detection circuit to detect the load applied to the upper surface 11 b of the load sensor 1 via the upper seal member 61 .

[0117] <Effects of Embodiment 1>

[0118] According to the first embodiment, the following effects are achieved.

[0119] The sealing member 60 has an air pressure regulating structure for making the air pressure in the storage space S of the load sensor 1 formed by the lower sealing member 62 and the upper sealing member 61 substantially equal to the external air pressure. In the first embodiment, the air pressure regulating structure includes a ventilation structure for ventilating the storage space S with the outside, and more specifically, the ventilation structure includes a mesh structure that prevents the entry and exit of water and oil and allows the entry and exit of gas.

[0120] According to this structure, since the load sensor 1 is enclosed in the sealing member 60, it is difficult for moisture, oil, or foreign matter to infiltrate the gap between the upper substrate 11 and the lower substrate 21. Therefore, it is possible to prevent the characteristics of the load sensor 1 from being deteriorated due to the intrusion of moisture, oil, or foreign matter. In addition, since the air pressure in the storage space S of the load sensor 1 is made substantially equal to the external air pressure by the air pressure adjustment structure, it is possible to suppress the reduction in detection accuracy caused by the air pressure difference between the storage space S and the outside. Therefore, the applied load can be accurately detected.

[0121] In addition, as described above, the air pressure adjustment structure includes a ventilation structure for ventilating the storage space S to the outside, so that the air pressure in the storage space S can be easily maintained at a state substantially equal to the external air pressure. Furthermore, the ventilation structure includes a mesh structure that prevents the entry and exit of moisture and oil and allows the entry and exit of gas, so that moisture and oil can be prevented from invading between the upper substrate 11 and the lower substrate 21, and the air pressure in the storage space S can be maintained at a state substantially equal to the external air pressure.

[0122] The mesh structure of the sealing member 60 is formed on the lower sealing member 62. In terms of structure, the rigidity of the mesh structure is easy to increase. In contrast, since the upper sealing member 61 is a member that bears the load, in order to properly transfer the applied load to the upper substrate 11 of the load sensor 1, it is preferred that the upper sealing member 61 is as soft as possible. On the other hand, for the lower sealing member 62, in order to support the joined upper sealing member 61 in a desired state, it is preferred that the rigidity is as high as possible. Therefore, by forming a mesh structure that is easy to increase the rigidity in the lower sealing member 62, the softness of the upper sealing member 61 can be maintained to improve the detection accuracy of the load, and the lower sealing member 62 can be used to support the upper sealing member 61 in a desired state.

[0123] The load sensor 1 is enclosed in the sealing member 60 in such a way that the sealing member 61 is closely attached to the upper surface 11b of the upper substrate 11. For the upper sealing member 61, although it is slightly slight, it may still produce differences in softness due to position differences. Therefore, if the upper sealing member 61 is displaced relative to the upper substrate 11, the distribution of the softness of the upper sealing member 61 relative to the upper substrate 11 may change, and the detection sensitivity of the load in each element part A11~A33 may change. As a result, the stability of the load detection in the same element part A1 may be slightly reduced. In contrast, according to the above structure, the situation where the upper sealing member 61 is displaced relative to the upper substrate 11 can be suppressed. Therefore, the change of the load detection sensitivity in the element parts A11~A33 can be suppressed, and the load can be stably detected.

[0124] The rigidity of the lower sealing member 62 is higher than that of the upper sealing member 61. According to this structure, the upper sealing member 61 joined to the lower sealing member 62 can be supported in a desired state by the lower sealing member 62. Thus, for example, the upper sealing member 61 can be properly maintained in a state of close contact with the upper surface 11b of the upper substrate 11, and the situation where the upper sealing member 61 is displaced relative to the upper substrate 11 can be suppressed. Therefore, the load can be stably detected. In addition, when the rigidity of the lower sealing member 62 is relatively high, the load applied to the load detection device 2 can be prevented from being released to the surroundings via the lower substrate 21, so the load can be properly detected. Furthermore, the shape of the load detection device 2 when viewed from above can be maintained, so the situation where the upper substrate 11 and the lower substrate 21 are bent and damaged can be avoided.

[0125] <Modification Example of Embodiment 1>

[0126] In the first embodiment, the upper sealing member 61 and the lower sealing member 62 are joined together in such a manner that the sealing member 60 completely accommodates the load sensor 1. However, if at least an accommodating space S is formed to cover the gap between the upper substrate 11 and the lower substrate 21, for example, Figure 8 (a) Figure 8 As shown in (b) , the sealing member 60 does not necessarily have to completely accommodate the load sensor 1 .

[0127] Figure 8 (a) Figure 8 (b) are a plan view and a cross-sectional view schematically showing the structure of a load detection device 2 according to a modified example of the first embodiment.

[0128] In this modification, compared with Embodiment 1, the end of the Y-axis negative side of the upper sealing member 61 and the end of the Y-axis negative side of the lower sealing member 62 are arranged at the position of the substrate 25 in the Y-axis direction. The upper surface of the substrate 25 has a substantially planar shape. The end of the Y-axis negative side of the upper sealing member 61 is located between the end of the Y-axis positive side of the upper surface of the substrate 25 and the end of the Y-axis positive side of the connector 26, 27, and is bonded to the upper surface of the substrate 25 using an adhesive or the like. The end of the Y-axis negative side of the lower sealing member 62 is located on the lower surface of the lower substrate 21 located below the substrate 25, and is bonded to the lower surface of the substrate 25 using an adhesive or the like.

[0129] As in the first embodiment, the upper sealing member 61 and the lower sealing member 62 are bonded to each other at the outer edge portions except for the portion overlapping with the substrate 25. Figure 8 The inner surfaces of the upper sealing member 61 and the lower sealing member 62 at the positions indicated by the dotted lines in (a) are bonded to the side surfaces of the substrate 25 and the lower substrate 21 by an adhesive.

[0130] like Figure 8 (a) Figure 8 As shown in (b), similarly to the first embodiment, the upper sealing member 61 and the lower sealing member 62 are joined to form the sealing member 60 to enclose the load sensor 1. Also, similarly to the first embodiment, the upper sealing member 61 and the lower sealing member 62 form a storage space S for the load sensor 1.

[0131] In this modification, since the load sensor 1 is enclosed in the sealing member 60, it is not easy for moisture, oil or foreign matter to intrude into the gap between the upper substrate 11 and the lower substrate 21. Therefore, it is possible to prevent the characteristics of the load sensor 1 from being deteriorated due to the intrusion of moisture, oil or foreign matter. In addition, since the air pressure in the storage space S of the load sensor 1 is roughly equal to the external air pressure by utilizing the mesh structure of the lower sealing member 62, it is possible to suppress the reduction in detection accuracy caused by the air pressure difference between the storage space S and the outside. Therefore, the applied load can be accurately detected. In addition, since the connectors 26 and 27 are exposed to the outside, the cable 70 can be easily loaded and unloaded.

[0132] In addition, the above-described method of installing the sealing member 60 can also be applied to the embodiments and modifications other than this modification.

[0133] <Implementation method 2>

[0134] In the first embodiment, the lower sealing member 62 has a mesh structure, thereby making the air pressure in the storage space S of the load sensor 1 substantially equal to the external air pressure. In contrast, in the second embodiment, the air vent provided in the sealing member 60 is used to make the air pressure in the storage space S substantially equal to the external air pressure.

[0135] Fig. 9 (a) Fig. 9 (b) are a plan view and a cross-sectional view schematically showing the structure of the load detection device 2 according to the second embodiment.

[0136] In implementation mode 2, Figure 7 (a) Figure 7 Compared to the first embodiment (b), the lower sealing member 62 does not include a mesh structure, but is made of an airtight raw material. In addition, a vent 63 that passes through the upper sealing member 61 is formed near the outer edge of the upper sealing member 61, and a cover 64 for sealing the vent 63 is provided at the vent 63 in a manner that can be loaded and unloaded relative to the vent 63. The cover 64 is a cover that can open the vent 63 in stages according to the degree of rotation relative to the vent 63, and is a so-called screw cap. If the upper sealing member 61 and the lower sealing member 62 are joined in the same manner as in the first embodiment, the load sensor 1 is enclosed in the interior of the sealing member 60, and a storage space S for the load sensor 1 is formed. When the cover 64 is provided, the storage space S in this case becomes isolated from the outside.

[0137] According to the second embodiment, as a ventilation structure for ventilating the storage space S enclosing the load sensor 1 to the outside, a vent 63 formed on the outside of the load sensor 1 in a plan view is formed. According to this structure, when the load detection device 2 is used, by loosening the cover 64, the air pressure in the storage space S can be easily maintained at a state substantially equal to the outside air pressure through the vent 63 while maintaining a state in which moisture, dust, etc. are not easily intruded. In addition, since the vent 63 is formed on the outside of the load sensor 1 in a plan view, even if moisture, oil, or foreign matter, etc. intrudes from the vent 63, it is not easy for the moisture, oil, or foreign matter, etc. to intrude into the gap between the upper substrate 11 and the lower substrate 21. Therefore, it is possible to appropriately suppress the degradation of the characteristics of the load sensor 1.

[0138] In addition, the position of the vent 63 is not limited to Fig. 9 However, when using the load detection device 2, in order to suppress the intrusion of foreign matter from the vent 63 into the load sensor 1, it is preferred that the vent 63 is located at a position that does not overlap with the load sensor 1 when viewed from above, and more preferably, is as far outward as possible from the outer edge of the load sensor 1.

[0139] <Modification Example of Embodiment 2>

[0140] In the second embodiment, the vent 63 is opened when the load detection device 2 is used, but the vent 63 is not limited to being opened when in use, and may be always opened. Fig.10 (a) Fig.10 As shown in (b) of FIG. 1 , a filter 65 is provided at the vent 63 .

[0141] Fig.10 (a) Fig.10 (b) are a plan view and a cross-sectional view schematically showing the structure of a load detection device 2 according to a modified example of the second embodiment.

[0142] In this modification example, Fig. 9 (a) Fig. 9 Compared with the embodiment 2 of (b), a filter 65 is provided relative to the vent 63. The other structures are the same as those of the embodiment 2. The filter 65 has tiny holes that prevent the entry and exit of water and oil and allow the entry and exit of gas. In addition, the tiny holes of the filter 65 can also be tiny holes of a degree that dust and the like are not easy to pass through.

[0143] According to this modification, instead of operating the cover 64 as in Embodiment 2, the air pressure in the storage space S can be easily maintained at a state substantially equal to the external air pressure via the vent 63 and the filter 65 (vent). In addition, since the filter 65 is provided at the vent 63, it is possible to prevent moisture, oil, foreign matter, etc. from intruding from the vent 63.

[0144] In addition, the vent hole 63 may be formed in the upper sealing member 61 of the first embodiment and the modification of the first embodiment.

[0145] <Implementation method 3>

[0146] As a structure for adjusting the air pressure of the storage space S of the load sensor 1, in the third embodiment, Fig.11 (a) Fig.11 As shown in FIG. 2 ( b ), a slack portion 66 is formed in the sealing member 60 .

[0147] Fig.11 (a) Fig.11 (b) are a plan view and a cross-sectional view schematically showing the structure of the load detection device 2 according to the third embodiment.

[0148] In implementation mode 3, Fig. 9 (a) Fig. 9Compared with the second embodiment (b), a slack portion 66 is formed on the upper sealing member 61 instead of the vent 63. The slack portion 66 is formed on the outer side of the load sensor 1 in the positive direction of the Y axis when viewed from above. The slack portion 66 has a shape that bulges to a large extent in the positive direction of the Z axis. The capacity of the slack portion 66 changes according to the difference between the air pressure in the storage space S and the external air pressure. The portion of the upper sealing member 61 other than the slack portion 66 is adhered to the upper surface 11b of the upper substrate 11 in a tightly fitted state using an adhesive or the like.

[0149] The rigidity of the relaxation portion 66 is lower than the rigidity of the portion of the upper sealing member 61 other than the relaxation portion 66. As a structure for reducing the rigidity of the relaxation portion 66, for example, the thickness of the relaxation portion 66 is made smaller than the thickness of the portion of the upper sealing member 61 other than the relaxation portion 66. In order to change the thickness of the relaxation portion 66, the number of layers of the film-like sheet material constituting the relaxation portion 66 may be changed, or the thickness may be changed by film forming. In addition, the elastic modulus of the material constituting the relaxation portion 66 may be greater than the elastic modulus of the material constituting the portion of the upper sealing member 61 other than the relaxation portion 66. In this case, for example, after forming the portion of the upper sealing member 61 other than the relaxation portion 66, a material having an elastic modulus lower than that of the portion may be attached to the portion as the relaxation portion 66 by using an adhesive or by thermal fusion, thereby forming the upper sealing member 61. As the relaxation portion 66, for example, a rubber material or the like can be used.

[0150] In addition, the slack portion 66 is not limited to being provided on the outside of the load sensor 1 in the positive direction of the Y axis, and may be provided on the outside of other sides of the load sensor 1, or may be provided on the outside of four sides of the load sensor 1. In addition, the slack portion 66 is not limited to being long in one direction in a plan view, and may be circular or rectangular.

[0151] According to Embodiment 3, as the air pressure adjustment structure, a slack portion 66 whose capacity changes according to the difference between the air pressure in the storage space S and the external air pressure is formed. According to this structure, the volume of the storage space S including the slack portion 66 changes according to the air pressure difference between the air pressure in the storage space S and the external air pressure, and the air pressure difference can be eliminated. Therefore, the air pressure in the storage space S can be easily maintained in a state substantially equal to the external air pressure.

[0152] The slack portion 66 is formed in the upper sealing member 61. By forming the slack portion 66 in the upper sealing member 61, which is preferably relatively soft, the slack portion 66 can be relatively soft. Therefore, the slack portion 66 can be easily deformed according to the air pressure difference between the air pressure in the storage space S and the external air pressure, and the volume of the storage space S including the slack portion 66 can be smoothly changed to a state in which the air pressure difference can be eliminated.

[0153] The slack portion 66 is configured to be more easily deformed than the portion of the upper sealing member 61 where the slack portion 66 is not formed. According to this structure, the slack portion 66 is mainly deformed according to the air pressure difference between the air pressure in the storage space S and the external air pressure. Thus, it is possible to suppress the portion of the upper sealing member 61 other than the slack portion 66 from being displaced relative to the upper substrate 11 due to the air pressure difference. Therefore, the load can be stably detected.

[0154] In addition, although the upper sealing member 61 is made as homogeneous as possible, there is still unevenness in the distribution of softness. Therefore, when the upper sealing member 61 is displaced relative to the upper substrate 11 due to the air pressure difference, the distribution of the softness of the upper sealing member 61 relative to the upper substrate 11 changes, and the characteristics of the load detection in the same element part A1 change. As a result, the stability of the load detection in the same element part A1 may be slightly reduced. In contrast, in the above-mentioned structure, it is possible to suppress the situation where the upper sealing member 61, except for the slack portion 66, is displaced relative to the upper substrate 11 due to the air pressure difference. Therefore, in the same element part A1, the load can be stably detected.

[0155] The upper sealing member 61 is attached to the upper surface 11b of the upper substrate 11. According to this structure, even if the volume of the storage space S including the slack portion 66 changes due to the pressure difference between the air pressure in the storage space S and the external air pressure, the upper sealing member 61 does not shift relative to the upper substrate 11. Therefore, the load can be stably detected.

[0156] In addition, in the above-mentioned structure, the stiffness of the slack portion 66 is constructed to be lower than the stiffness of the portion of the upper sealing member 61 other than the slack portion 66, but if the slack portion 66 can be smoothly deformed according to the air pressure difference between the air pressure in the storage space S and the external air pressure, then it is also possible that the stiffness of the slack portion 66 is not lower than the stiffness of the portion of the upper sealing member 61 other than the slack portion 66.

[0157] In addition, Fig.11 (a) Fig.11 In the structure of (b), the slack portion 66 and the portion of the upper sealing member 61 other than the slack portion 66 are clearly distinguished, but it may also be, for example Fig.12 (a) Fig.12 As shown in (b), the upper seal member 61 is joined to the lower seal member 62 in a relaxed state with a margin, thereby forming a slack portion 66. In this case, the entire upper seal member 61 including the slack portion 66 may be uniformly formed of a material having the same rigidity.

[0158] <Implementation method 4>

[0159] In the first to third embodiments, the upper sealing member 61 is formed in a sheet shape. Fig.13 (a) Fig.13 As shown in FIG. 2( b ), a pressure receiving portion 67 is provided on the lower surface of the upper sealing member 61 .

[0160] Fig.13 (a) Fig.13 (b) are a plan view and a cross-sectional view schematically showing the structure of the load detection device 2 according to the fourth embodiment.

[0161] In implementation mode 4, Figure 7 (a) Figure 7 Compared with the first embodiment of (b), the upper sealing member 61 has a plurality of pressure-receiving portions 67 arranged at positions corresponding to the plurality of element portions A1, respectively, and a thin-walled portion 68 formed between adjacent pressure-receiving portions 67. The thickness of the pressure-receiving portion 67 is greater than the thickness of the outer edge portion of the upper sealing member 61, and the pressure-receiving portion 67 protrudes from the lower surface of the upper sealing member 61 in the negative direction of the Z axis. The thin-walled portion 68 is thinnest at the center in the width direction, and gradually becomes thinner as it moves from both ends toward the center in the width direction.

[0162] According to Embodiment 4, the load applied to the pressure receiving portion 67 is effectively transmitted to the element portion A1 corresponding to the pressure receiving portion 67. Therefore, the load applied to the upper surface of the load detection device 2 (upper surface of the upper seal member 61) can be detected with high accuracy.

[0163] In addition, the structure of the upper seal member 61 as described above can also be applied to embodiments and modifications other than the present embodiment.

[0164] <Modification example of embodiment 4>

[0165] In the fourth embodiment, one load sensor 1 is enclosed in the sealing member 60, but the present invention is not limited thereto, and a plurality of load sensors 1 may be enclosed in the sealing member 60. For example, Fig.14 , Fig.15 As shown, three load sensors 1 may be enclosed in one sealing member 60 .

[0166] Fig.14 It is a plan view schematically showing the structure of a load detection device 2 according to a modified example of the fourth embodiment.

[0167] In this modification, the same three load sensors 1 as those in the above embodiment are arranged adjacent to each other in the X-axis direction, and the three load sensors 1 are enclosed in one sealing member 60. The sealing member 60 has a shape that is longer in the X-axis direction so as to be able to accommodate the three load sensors 1. The three cables 70 connected to the three load sensors 1 are pulled out from between the upper sealing member 61 and the lower sealing member 62 independently. In addition, the three cables 70 may be gathered into one cable in the sealing member 60, and the gathered cables 70 may be pulled out from the sealing member 60 at one location.

[0168] Fig.15 It is a cross-sectional view schematically showing the structure of a load detection device 2 according to a modified example of the fourth embodiment.

[0169] Two adjacent load sensors 1 are arranged so that the upper substrates 11 are in contact with each other and the lower substrates 21 are in contact with each other. In order to prevent the position of each load sensor 1 from shifting in the horizontal direction, for example, the lower surface 21b of the lower substrate 21 of each load sensor 1 may be adhered to the upper surface of the lower sealing member 62 using an adhesive, or one substrate may be arranged between each lower substrate 21 and the lower sealing member 62 in a manner spanning three lower surfaces 21b.

[0170] The sealing member 60 includes a pressure receiving portion 67 and a thin-walled portion 68 similar to those of the fourth embodiment, and a thin-walled portion 69 formed across the boundary B1 between adjacent load sensors 1. The thin-walled portion 69 is thinnest at the center in the width direction and gradually becomes thinner from both ends toward the center. Fig.15 By configuring as shown, even when a load is applied to the boundary B1, the load can be appropriately transmitted to the element portion A1 adjacent to the boundary B1.

[0171] The material of the sealing member 60 of this modification is the same as that of the first embodiment, and the lower sealing member 62 has a mesh structure. The pressure receiving portion 67 of the upper sealing member 61 is arranged to be in close contact with the upper surface of the load sensor 1 (upper surface 11b of the upper substrate 11).

[0172] Reference Fig.16 (a) Fig.16 (b) illustrates the effect of the structure of the thin-walled portion 69 formed at the boundary B1.

[0173] Fig.16 (a) is a cross-sectional view schematically showing the structure of the load detection device 2 in the vicinity of the boundary B1 of the comparative example.

[0174] In the comparative example, three Fig.13 (a) Fig.13The load detection device 2 of the fourth embodiment is shown in (b). In this case, a dead zone, which is a region where the load cannot be detected, is generated near the boundary B1 between the adjacent load sensors 1 .

[0175] Fig.16 (b) is a cross-sectional view schematically showing the structure of the load detection device 2 near the boundary B1 according to the modification of the fourth embodiment.

[0176] In this modification, a thin-walled portion 69 is formed at the boundary B1 of the adjacent load sensors 1. As described above, the thin-walled portion 69 is thinnest at the center in the width direction, and gradually becomes thinner from both ends toward the center. Thus, the load applied to the boundary B1 of the adjacent load sensors 1 is transmitted to the element portion A1 adjacent to the boundary B1. Therefore, the load can be appropriately detected.

[0177] As described above, according to the modification example of the fourth embodiment, the following effects are achieved.

[0178] like Fig.14 As shown in FIG. 1 , a plurality of load sensors 1 are enclosed in a single sealing member 60. According to this structure, the sealing operation can be facilitated compared to the case where a plurality of load sensors 1 are individually sealed. In addition, if a plurality of load sensors 1 are individually sealed and arranged, the sealing member 60 is sandwiched between adjacent load sensors 1, so that the dead zone where the load cannot be detected becomes larger. In contrast, in the above-mentioned structure, since a plurality of load sensors 1 are enclosed in a single sealing member 60, Fig.16 As shown in (b) of FIG. 1 , the sealing member 60 is not sandwiched between adjacent load sensors 1 . Therefore, a dead space at the boundary B1 between the load sensors 1 can be suppressed.

[0179] A plurality of conductive elastic bodies 13 and a plurality of conductive members 41 (linear conductive members) are disposed in each load sensor 1, so that the element portion A1 for load detection formed by the intersection of the conductive elastic body 13 and the conductive member 41 (linear conductive member) is arranged along the X-axis direction (first direction) and the Y-axis direction (second direction) when viewed from above. The plurality of load sensors 1 are enclosed in the sealing member 60 in a manner adjacent to each other in the X-axis direction (first direction). The upper sealing member 61 has a plurality of pressure-bearing portions 67 disposed at positions corresponding to the plurality of element portions A1, respectively, and thin-walled portions 68 and 69 formed between adjacent pressure-bearing portions 67. The thin-walled portion 69 located at the boundary B1 of adjacent load sensors 1 is formed across the boundary B1. According to this structure, the dead zone at the boundary B1 of adjacent load sensors 1 can be further suppressed. That is, as Fig.16 As shown in (b) of FIG. 1 , the pressure receiving portion 67 can also be arranged near the boundary B1 , and the load applied to the pressure receiving portion 67 can be transmitted to the corresponding element portion A1 .

[0180] The thin-walled portions 68 and 69 are thinnest in the center in the width direction and gradually become thinner from both ends toward the center. The width of the thin-walled portion 69 located at the boundary B1 is larger than the width of the other thin-walled portions 68. According to this structure, the pressure-bearing portion 67 near the boundary B1 of the adjacent load sensor 1 can be brought close to the boundary B1, and the load applied to the pressure-bearing portion 67 can be effectively transmitted to the element portion A1 corresponding to the pressure-bearing portion 67. Therefore, the dead zone near the boundary B1 can be further suppressed, and as shown in FIG. Fig.16 As described in (b), the load applied near the boundary B1 can be detected more accurately.

[0181] Furthermore, the above-described structure in which a plurality of load sensors 1 are sealed in one sealing member 60 can also be applied to the embodiments and modifications other than this modification.

[0182] <Implementation method 5>

[0183] When the electrostatic capacitance component (electromagnetic noise) approaches the load detection device 2, the change in the measured potential will produce an error under the influence of the electromagnetic noise. As a result, the detection accuracy of the electrostatic capacitance is reduced. In contrast, in the fifth embodiment, as shown below, the load detection device 2 is configured in a manner that blocks the electromagnetic noise.

[0184] Fig.17 (a) is a cross-sectional view schematically showing a load detection device 2 in a case where a conductive coating is applied to the outer surface of a sealing member 60 according to Embodiment 5. For convenience, the conductive coating is indicated by a dot-dash line.

[0185] In this example, compared with Embodiment 2, a thin film of metal or the like, a surfactant layer or the like is formed as a conductive coating on the outer surfaces of the upper sealing member 61 and the lower sealing member 62 made of insulating material. The conductive coating is, for example, a conductive film (metal, metal oxide, conductive polymer, carbon).

[0186] By imparting conductivity to the material surface of the sealing member 60 in this manner, electromagnetic noise from the outside can be blocked by the sealing member 60. Therefore, the capacitance of the element portion A1 can be accurately measured, and the accuracy of load detection can be maintained high.

[0187] In addition, Fig.17 In the structure of (a), a conductive coating may be applied to the inner surface of the upper sealing member 61 and the inner surface of the lower sealing member 62 .

[0188] The sealing member 60 may be made of a conductive material instead of applying a conductive coating on the surface of the sealing member 60 .

[0189] Fig.17(b) is a cross-sectional view schematically showing the load detection device 2 in the case where the sealing member 60 is made of a conductive material according to the fifth embodiment.

[0190] In this example, the sealing member 60 is made of a conductive material or a material with lower insulation than in Embodiment 2. Alternatively, the sealing member 60 may be made of a material obtained by mixing a conductive substance into an insulating material similar to that in Embodiment 1.

[0191] In this case, an electrode 71 is provided on the lower surface 21b of the lower substrate 21 located below the substrate 25. The electrode 71 is connected to the lower end of a wiring 72 that passes through the lower substrate 21 in the up-down direction, and the upper end of the wiring 72 is connected to the connector 26 or the connector 27 via the substrate 25. The terminal of the connector 26 or the connector 27 connected with the wiring 72 is connected to a specific potential of an external detection circuit via a cable 70. The specific potential may be a ground potential or a potential other than the ground potential.

[0192] During assembly, if the load sensor 1 is placed on the lower sealing member 62, the electrode 71 is electrically connected to the lower sealing member 62. As described above, in this example, since the upper sealing member 61 and the lower sealing member 62 are conductive, the entire sealing member 60 is connected to a specific potential via the electrode 71, the wiring 72, and the cable 70.

[0193] Thus, if the sealing member 60 has conductivity and is connected to a specific potential, the electromagnetic shielding effect can be improved. Thus, the electromagnetic noise from the outside can be blocked by the sealing member 60. Therefore, the electrostatic capacitance of the element part A1 can be accurately measured, and the accuracy of the load detection can be maintained high.

[0194] In addition, Fig.17 In the structure of (b), the terminal connected to the specific potential of the connector 26 or the connector 27 can also be directly connected to the upper surface of the lower sealing member 62 via a cable, rather than via the electrode 71, the wiring 72 and the substrate 25. In this case, one end of the cable is connected to the upper surface of the lower sealing member 62 using solder, for example.

[0195] As described above, according to the fifth embodiment, the following effects are achieved.

[0196] like Fig.17 (a) Fig.17 As shown in (b), at least one of the upper sealing member 61 and the lower sealing member 62 has conductivity. According to this structure, electromagnetic noise from the outside can be blocked by the sealing member 60. Therefore, it is possible to suppress the reduction in load detection accuracy caused by electromagnetic noise.

[0197] like Fig.17As shown in (b), the conductive member of the upper sealing member 61 and the lower sealing member 62 is electrically connected to a specific potential of the load sensor 1. Fig.17 In the example of (b), both the upper sealing member 61 and the lower sealing member 62 are conductive, and the sealing member 60 as a whole is connected to a terminal connected to a specific potential of the connector 26 or the connector 27 via the electrode 71, the wiring 72 and the substrate 25. According to this structure, the shielding effect of electromagnetic noise can be improved. Therefore, the reduction in load detection accuracy caused by electromagnetic noise can be further suppressed.

[0198] In addition, Fig.17 (a) Fig.17 In (b), based on the structure of the second embodiment, a conductive coating is applied on the surface of the sealing member 60, and the sealing member 60 is made of a conductive material, but the above-mentioned additional structure can also be applied to embodiments and modified examples other than the above-mentioned second embodiment.

[0199] In addition, the above-described structure for blocking electromagnetic noise can also be applied to embodiments and modifications other than this embodiment.

[0200] <Other changes>

[0201] In the above-mentioned embodiment and modification, the sealing member 60 may also have a structure for preventing ultraviolet rays from irradiating the load sensor 1 in the storage space S. For example, the sealing member 60 is made of a material that absorbs ultraviolet rays and does not transmit ultraviolet rays. As such a material, for example, a high molecular polymer can be cited. In addition, a material that scatters and reflects ultraviolet rays can also be arranged on the surface of the sealing member 60. As such a material, for example, inorganic oxide particles such as titanium oxide can be cited. In addition, the structure for preventing ultraviolet rays can be provided at least on the upper sealing member 61.

[0202] When ultraviolet rays are irradiated to the load sensor 1, the rubber material (e.g., the conductive elastic body 13) constituting the load sensor 1 deteriorates, and the load cannot be accurately detected. In contrast, if a structure for preventing ultraviolet rays from entering the storage space S is provided as described above, the degradation of the rubber material constituting the load sensor 1 can be suppressed, and the accuracy of load detection can be maintained high.

[0203] In the above-mentioned embodiment and modification, the upper sealing member 61 may also have regions with different hardness when viewed from above. The difference in hardness is adjusted, for example, by using the thickness of the upper sealing member 61. In this way, if regions with different hardness are set on the upper sealing member 61, for example, it is possible to use the following method: the load is mainly detected in the harder region, and the distribution of the load is mainly detected in the softer region. Specifically, in a supermarket, the store manager can grasp the amount of remaining goods by placing fruits and vegetables in the softer region, and the customer can weigh the weight of the goods by placing the goods in the harder region.

[0204] In the above-described embodiment and modified examples, a QR code (registered trademark) may be printed on the upper surface of the upper seal member 61. In this way, the load detection device 2 can be individually identified by reading the QR code (registered trademark).

[0205] In the above-mentioned embodiment and modification, pictures and characters may be printed on the upper surface of the upper sealing member 61. For example, if pictures and characters indicating the types of commodities are printed on the upper surface of the upper sealing member 61, it is possible to understand what kind of commodities should be placed in the area where the pictures and characters are printed. In addition, when it is desired to change the pictures and characters, it is not necessary to replace them for each load detection device 2, but only the sealing member 60 can be replaced, so the pictures and characters can be changed at a low cost.

[0206] In the above-mentioned embodiments and variations, the upper sealing member 61 may also be made of a material with high impact absorption. For example, the upper sealing member 61 is made of a viscoelastic material, that is, a material that absorbs large instantaneous forces such as impact force and transmits stable forces such as the weight of the product. The upper sealing member 61 is made of, for example, a silicone gel such as αGEL (registered trademark) manufactured by Taica Corporation. Alternatively, the upper sealing member 61 may be made of a styrene elastomer or a polyurethane elastomer as long as it is a gel-like substance or a soft (ultra-soft) elastomer like silicone gel. If the upper sealing member 61 is made of the above-mentioned material, even if a heavier product falls on the load detection device 2, the impact of the fall is absorbed by the upper sealing member 61, thereby preventing the load sensor 1 from being damaged.

[0207] In the above-mentioned embodiments 1, 2, 4, 5 and their variations, the upper sealing member 61 is arranged in a manner of being closely attached to the upper surface of the load sensor 1 (the upper surface 11b of the upper substrate 11), but the upper sealing member 61 may also be attached to the upper surface 11b of the upper substrate 11 in a closely attached state using an adhesive or the like. In addition, in the above-mentioned embodiments and variations, the upper sealing member 61 and the lower sealing member 62 are not limited to being joined using an adhesive, and may also be joined by, for example, thermal welding.

[0208] In the above-mentioned embodiments and modifications, Figure 1 (a) Figure 1 As shown in (b), the load sensor 1 includes three sets of the conductive elastic body 13 and the conductive portion 12, but it is sufficient to include at least one set of the conductive elastic body 13 and the conductive portion 12. For example, the load sensor 1 may include only one set.

[0209] In the above-mentioned embodiments and modifications, Figure 3 As shown in (a) of FIG. 1 , the load sensor 1 includes three sets of a pair of conductive wires 40 , but it is sufficient to include at least one set of a pair of conductive wires 40 . For example, the load sensor 1 may include only one set of a pair of conductive wires 40 .

[0210] In the above-described embodiment and modification examples, the element portion A1 includes two conductive wires 40 arranged in the X-axis direction, but may include one or three or more conductive wires 40 .

[0211] In the above-mentioned embodiments and modifications, Figure 4 (a) Figure 4 As shown in (b), the conductor 40 is composed of a conductive member 41 and a dielectric 42 covering the conductive member 41. However, the present invention is not limited thereto, and the conductor 40 may be composed of a stranded wire formed by bundling a plurality of the above-mentioned conductors. In addition, the conductor 40 may be composed of a stranded wire formed by bundling a plurality of conductive members and a dielectric covering the stranded wire. In the above case, the flexibility of the conductor 40 can be improved, and the strength of the conductor 40 against bending can be improved.

[0212] In the above-described embodiment and modification examples, the X-axis direction (first direction) in which the conductive elastic body 13 and the conductive portion 12 extend is orthogonal to the Y-axis direction (second direction) in which the conductive wire 40 extends. However, the first direction and the second direction may not intersect at 90 degrees.

[0213] In the above-described embodiment and modification examples, the conductive portion 12 and the conductive elastic body 13 are formed on the facing surface 11 a of the upper substrate 11 , but may be formed on the facing surface 21 a of the lower substrate 21 .

[0214] Fig.18 2 is a cross-sectional view schematically showing the structure of the load detection device 2 in the above case.

[0215] exist Fig.18 In the example shown, the structure between the upper substrate 11 and the lower substrate 21 of the load sensor 1 is reversed in the vertical direction compared to the first embodiment. That is, the conductor 22, the wiring 23 and the terminal portion 24 are arranged on the opposite surface 11a of the upper substrate 11 (see Figure 2(a)), substrate 25 and connectors 26 and 27, a conductive portion 12 and a conductive elastic body 13 are formed on the opposite surface 21a of the lower substrate 21. In addition, a wire 40 is arranged on the upper surface of the conductive elastic body 13, and an insulating film 31 is arranged between the wire 40 and the upper substrate 11. In this case, the load applied to the upper surface of the upper sealing member 61 can also be detected by the load sensor 1.

[0216] Furthermore, conductive portion 12 and conductive elastic body 13 are not limited to being formed on either upper substrate 11 or lower substrate 21 , and may be formed on both opposing surface 11 a of upper substrate 11 and opposing surface 21 a of lower substrate 21 facing each other.

[0217] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical concept shown in the claims.

[0218] (Note)

[0219] Based on the description of the above embodiments, the following technology is disclosed.

[0220] (Technology 1)

[0221] A load detection device, characterized in that:

[0222] The load detection device has:

[0223] load cells; and

[0224] a sealing member enclosing the load sensor,

[0225] The load sensor comprises:

[0226] an upper substrate having elasticity;

[0227] a lower substrate, which is arranged opposite to the upper substrate;

[0228] at least one conductive elastic body formed on at least one of the opposing surface of the upper substrate and the opposing surface of the lower substrate;

[0229] at least one linear conductive member disposed between the upper substrate and the lower substrate; and

[0230] a dielectric formed on the outer periphery of the linear conductive member,

[0231] The sealing member comprises:

[0232] a lower sealing member on which the load sensor is mounted;

[0233] an upper sealing member covering an upper surface of the load sensor and engaging with the lower sealing member; and

[0234] The air pressure regulating structure is used to make the air pressure in the storage space of the load sensor formed by the lower sealing member and the upper sealing member substantially equal to the external air pressure.

[0235] According to this technology, since the load sensor is enclosed in a sealing member, it is not easy for moisture, oil, or foreign matter to intrude into the gap between the upper substrate and the lower substrate. Therefore, it is possible to prevent the characteristics of the load sensor from being deteriorated due to the intrusion of moisture, oil, or foreign matter. In addition, since the air pressure in the storage space of the load sensor is made roughly equal to the external air pressure by using an air pressure adjustment structure, it is possible to suppress the reduction in detection accuracy caused by the air pressure difference between the storage space and the outside. Therefore, the applied load can be accurately detected.

[0236] (Technique 2)

[0237] The load sensor according to the technique 1 is characterized in that:

[0238] The air pressure adjustment structure includes a ventilation structure for allowing ventilation of the storage space and the outside.

[0239] According to this technology, the air pressure in the storage space can be easily maintained in a state substantially equal to the external air pressure.

[0240] (Technique 3)

[0241] The load detection device described in the technique 2 is characterized in that:

[0242] The ventilation structure includes a mesh structure that blocks the entry and exit of water and oil but allows the entry and exit of gas.

[0243] According to this technology, it is possible to prevent moisture and oil from invading between the upper substrate and the lower substrate, and to maintain the air pressure in the storage space substantially equal to the external air pressure.

[0244] (Technique 4)

[0245] The load detection device described in technology 3 is characterized in that:

[0246] The mesh structure is formed on the lower sealing member.

[0247] In terms of structure, the rigidity of the mesh structure is easy to increase. In contrast, since the upper sealing member is a member that bears the load, in order to properly transfer the applied load to the upper substrate of the load sensor, it is preferred that the upper sealing member is as soft as possible. On the other hand, for the lower sealing member, in order to support the upper sealing member to be joined in a desired state, it is preferred that the rigidity is as high as possible. Therefore, by forming a mesh structure that is easy to increase the rigidity in the lower sealing member, the softness of the upper sealing member can be maintained to improve the detection accuracy of the load, and the lower sealing member can be used to support the upper sealing member in a desired state.

[0248] (Technique 5)

[0249] The load detection device according to any one of techniques 2 to 4 is characterized in that:

[0250] The ventilation structure includes a ventilation hole formed on an outer side of the load sensor in a plan view.

[0251] According to this technology, when the load detection device is used, the air pressure in the storage space can be easily maintained at a state substantially equal to the external air pressure through the vent. In addition, since the vent is formed on the outside of the load sensor when viewed from above, even if moisture, oil, or foreign matter enters through the vent, it is difficult for the moisture, oil, or foreign matter to enter the gap between the upper substrate and the lower substrate. Therefore, it is possible to appropriately suppress the degradation of the characteristics of the load sensor.

[0252] (Technique 6)

[0253] The load detection device described in the technique 1 is characterized in that:

[0254] The air pressure adjustment structure includes a slack portion whose capacity varies according to a difference between the air pressure in the storage space and the external air pressure.

[0255] According to this technology, the volume of the storage space including the slack portion changes according to the pressure difference between the air pressure in the storage space and the external air pressure, and the pressure difference can be eliminated. Therefore, the air pressure in the storage space can be easily maintained in a state substantially equal to the external air pressure.

[0256] (Technique 7)

[0257] The load detection device according to technology 6 is characterized in that:

[0258] The slack portion is formed in the upper sealing member.

[0259] By forming a slack portion in the upper sealing member, which is preferably relatively soft, the slack portion can be made relatively soft. Therefore, according to this technology, the slack portion can be easily deformed according to the pressure difference between the air pressure in the storage space and the external air pressure, and the volume of the storage space including the slack portion can be smoothly changed to a state that can eliminate the pressure difference.

[0260] (Technology 8)

[0261] The load detection device according to technology 7 is characterized in that:

[0262] The slack portion is configured to be more easily deformed than a portion of the upper seal member where the slack portion is not formed.

[0263] According to this technology, the slack portion is mainly deformed according to the pressure difference between the air pressure in the storage space and the external air pressure. Thus, it is possible to suppress the positional displacement of the upper sealing member other than the slack portion relative to the upper substrate due to the pressure difference. Therefore, the load can be stably detected.

[0264] (Technique 9)

[0265] The load detection device according to any one of techniques 6 to 8 is characterized in that:

[0266] The upper sealing member is attached to the upper surface of the upper substrate.

[0267] According to this technique, even if the volume of the storage space including the slack portion changes due to the pressure difference between the air pressure inside the storage space and the external air pressure, the upper sealing member does not shift relative to the upper substrate. Therefore, the load can be stably detected.

[0268] (Technology 10)

[0269] The load detection device according to any one of techniques 1 to 9 is characterized in that:

[0270] The plurality of load sensors are enclosed in one sealing member.

[0271] According to this technology, the sealing operation can be facilitated compared to the case where a plurality of load sensors are individually enclosed. In addition, if a plurality of load sensors are individually sealed and arranged, the sealing member is sandwiched between adjacent load sensors, and thus the dead zone where the load cannot be detected becomes larger. In contrast, in the above-mentioned technology, since a plurality of load sensors are enclosed in one sealing member, the sealing member is not sandwiched between adjacent load sensors. Therefore, the dead zone at the boundary between the load sensors can be suppressed.

[0272] (Technology 11)

[0273] The load detection device according to technology 10 is characterized in that:

[0274] A plurality of the conductive elastic bodies and a plurality of the linear conductive members are arranged in each of the load sensors, so that a load detection element portion formed by the intersection of the conductive elastic bodies and the linear conductive members is arranged in a first direction and a second direction intersecting the first direction when viewed from above.

[0275] The plurality of load sensors are enclosed by the sealing member so as to be adjacent to each other in the first direction.

[0276] The upper sealing member includes a plurality of pressure receiving portions arranged at positions corresponding to the plurality of element portions, respectively, and a thin-walled portion formed between adjacent pressure receiving portions.

[0277] The thin-walled portion located at the boundary between the adjacent load sensors is formed across the boundary.

[0278] According to this technique, the dead zone at the boundary between adjacent load sensors can be further suppressed. That is, a pressure receiving portion can also be arranged near the boundary, and the load applied to the pressure receiving portion can be transmitted to the corresponding element portion.

[0279] (Technology 12)

[0280] The load detection device according to technology 11 is characterized in that:

[0281] The thin-walled portion is thinnest at the center in the width direction and gradually becomes thinner from both ends toward the center.

[0282] The width of the thin-walled portion located at the boundary is larger than the width of the other thin-walled portions.

[0283] According to this technology, the pressure-bearing parts near the boundary of adjacent load sensors can be brought close to the boundary, and the load applied to the pressure-bearing parts can be effectively transmitted to the element part corresponding to the pressure-bearing parts. Therefore, the dead zone near the boundary can be further suppressed, and the load applied near the boundary can be detected more accurately.

[0284] (Technology 13)

[0285] The load detection device according to any one of techniques 1 to 12 is characterized in that:

[0286] At least one of the upper sealing member and the lower sealing member has conductivity.

[0287] According to this technique, electromagnetic noise from the outside can be blocked by the sealing member, so that a decrease in load detection accuracy due to electromagnetic noise can be suppressed.

[0288] (Technology 14)

[0289] The load detection device described in technology 13 is characterized in that:

[0290] One of the upper sealing member and the lower sealing member having conductivity is electrically connected to a specific potential of the load sensor.

[0291] According to this technology, the shielding effect of electromagnetic noise can be improved, and therefore, the reduction in load detection accuracy caused by electromagnetic noise can be further suppressed.

[0292] (Technology 15)

[0293] The load detection device according to any one of techniques 1 to 14 is characterized in that:

[0294] The load sensor is enclosed in the sealing member in such a manner that the upper sealing member is in close contact with the upper surface of the upper substrate.

[0295] According to this technology, for the upper sealing member, although it is slightly slight, it is still possible to produce differences in softness according to the position difference. Therefore, if the upper sealing member is displaced relative to the upper substrate, the distribution of the softness of the upper sealing member relative to the upper substrate may change, and the detection sensitivity of the load may vary according to the region. As a result, there is a concern that the stability of the load detection in the same area is slightly reduced. In contrast, according to the above technology, the situation where the upper sealing member is displaced relative to the upper substrate can be suppressed. Therefore, the change of the load detection sensitivity according to the region can be suppressed, and the load can be stably detected.

[0296] (Technology 16)

[0297] The load detection device according to any one of techniques 1 to 15 is characterized in that:

[0298] The lower sealing member has a higher rigidity than the upper sealing member.

[0299] According to this technology, the lower sealing member can be used to support the upper sealing member engaged with the lower sealing member in a desired state. Thus, for example, the upper sealing member can properly maintain a state of close contact with the upper surface of the upper substrate, and the situation in which the upper sealing member is displaced relative to the upper substrate can be suppressed. Therefore, the load can be stably detected. In addition, in the case where the rigidity of the lower sealing member is relatively high, the load applied to the load detection device can be prevented from being released to the surroundings via the lower substrate, so the load can be properly detected. Furthermore, since the shape of the load detection device when viewed from above can be maintained, it is possible to avoid the situation in which the upper substrate and the lower substrate are bent and damaged.

[0300] Description of Reference Numerals

[0301] 1. Load sensor; 11. Upper substrate; 11a. Opposite surface; 11b. Upper surface; 13. Conductive elastic body; 21. Lower substrate; 21a. Opposite surface; 41. Conductive member (linear conductive member); 42. Dielectric; 60. Sealing member; 61. Upper sealing member; 62. Lower sealing member; 63. Vent (air pressure regulating structure, ventilation structure); 65. Filter (air pressure regulating structure, ventilation structure, vent); 66. Relaxed portion (air pressure regulating structure); 67. Pressure-bearing portion; 68, 69. Thin-walled portion; A1, A11 to A33, element portion; B1, boundary; S, storage space.

Claims

1. A load detection device, characterized in that: The load detection device has: load cells; and a sealing member enclosing the load sensor, The load sensor comprises: an upper substrate having elasticity; a lower substrate, which is arranged opposite to the upper substrate; at least one conductive elastic body formed on at least one of the opposing surface of the upper substrate and the opposing surface of the lower substrate; at least one linear conductive member disposed between the upper substrate and the lower substrate; and a dielectric formed on the outer periphery of the linear conductive member, The sealing member comprises: a lower sealing member on which the load sensor is mounted; an upper sealing member covering an upper surface of the load sensor and engaging with the lower sealing member; and The air pressure regulating structure is used to make the air pressure in the storage space of the load sensor formed by the lower sealing member and the upper sealing member substantially equal to the external air pressure.

2. The load sensor according to claim 1, characterized in that: The air pressure adjustment structure includes a ventilation structure for allowing ventilation of the storage space and the outside.

3. The load detection device according to claim 2, characterized in that: The ventilation structure includes a mesh structure that blocks the entry and exit of water and oil but allows the entry and exit of gas.

4. The load detection device according to claim 3, characterized in that: The mesh structure is formed on the lower sealing member.

5. The load detection device according to claim 2, characterized in that: The ventilation structure includes a ventilation hole formed on an outer side of the load sensor in a plan view.

6. The load detection device according to claim 1, characterized in that: The air pressure adjustment structure includes a slack portion whose capacity varies according to a difference between the air pressure in the storage space and the external air pressure.

7. The load detection device according to claim 6, characterized in that: The slack portion is formed in the upper sealing member.

8. The load detection device according to claim 7, characterized in that: The slack portion is configured to be more easily deformed than a portion of the upper seal member where the slack portion is not formed.

9. The load detection device according to claim 6, characterized in that: The upper sealing member is attached to the upper surface of the upper substrate.

10. The load detection device according to claim 1, characterized in that: The plurality of load sensors are enclosed in one sealing member.

11. The load detection device according to claim 10, characterized in that: A plurality of the conductive elastic bodies and a plurality of the linear conductive members are arranged in each of the load sensors, so that a load detection element portion formed by the intersection of the conductive elastic bodies and the linear conductive members is arranged in a first direction and a second direction intersecting the first direction when viewed from above. The plurality of load sensors are enclosed by the sealing member so as to be adjacent to each other in the first direction. The upper sealing member includes a plurality of pressure receiving portions arranged at positions corresponding to the plurality of element portions, respectively, and a thin-walled portion formed between adjacent pressure receiving portions. The thin-walled portion located at the boundary between the adjacent load sensors is formed across the boundary.

12. The load detection device according to claim 11, characterized in that: The thin-walled portion is thinnest at the center in the width direction and gradually becomes thinner from both ends toward the center. The width of the thin-walled portion located at the boundary is larger than the width of the other thin-walled portions.

13. The load detection device according to claim 1, characterized in that: At least one of the upper sealing member and the lower sealing member has conductivity.

14. The load detection device according to claim 13, characterized in that: One of the upper sealing member and the lower sealing member having conductivity is electrically connected to a specific potential of the load sensor.

15. The load detection device according to claim 1, characterized in that: The load sensor is enclosed in the sealing member in such a manner that the upper sealing member is in close contact with the upper surface of the upper substrate.

16. The load detection device according to claim 1, characterized in that: The lower sealing member has a higher rigidity than the upper sealing member.

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