Measurement device and load detection system

Abstract

A measurement device (200) is provided with: a switching unit (202) for switching a voltage application unit (100) between an application voltage and a non-application voltage; a measurement unit (203) that measures the current of the supply line (L0) of the voltage application unit (100); and a control unit (201) that controls the switching unit (202) and the measurement unit (203) so as to measure the current that changes and is saturated in the supply line (L0). The control unit (201) performs the following processes: setting a plurality of measurement periods that are different from each other; starting the application of the voltage in synchronization with the start of each measurement period; determining whether or not the current measured by the measuring unit (203) is saturated during each measurement period; and acquiring a measurement result of the current on the basis of the measurement period in which the current has been determined to be saturated.

Description

Technical Field

[0001] The present invention relates to a measuring device for measuring electric quantity which changes and becomes saturated with the application of voltage, and a load detection system using the measuring device. Background Art

[0002] Conventionally, there is known a capacitance type load sensor in which the capacitance of a component part changes according to a load. In such a load sensor, the capacitance of the component part is detected based on, for example, a change in voltage when a voltage is applied to the component part. A load detection device using such a load sensor is described in, for example, the following patent document 1.

[0003] In addition, a current measuring device capable of measuring the current flowing through a circuit within a measurement range from a low current value to a high current value is described in the following patent document 2. In this device, two sensors, a high range sensor and a low range sensor, are used to measure the current flowing through the measured wire.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-81209

[0007] Patent Document 2: Japanese Patent Application Publication No. 2005-91021 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In a capacitive load sensor, the capacitance of the element portion can be detected based on the amount of charge accumulated in the element portion when a voltage is applied to the element portion. In this case, for example, the amount of charge accumulated in the element portion can be calculated by measuring the current flowing through the element portion from the time the voltage is applied to the element portion until the accumulated charge is saturated.

[0010] On the other hand, the electrostatic capacitance of the element part changes according to the range of the load to be detected (dynamic range). Therefore, the period until the accumulation of charge in the element part is completed changes according to the load applied to the element part. Therefore, when measuring the current flowing through the element part as described above, the period required for current measurement changes according to the load.

[0011] In this case, a method can be used in which the measurement period required when the maximum load is applied to the component unit is applied to all loads within the dynamic range. However, in this method, since a long measurement period for a high load is applied even when the load applied to the component unit is small, a problem occurs in that the load cannot be detected efficiently. In the above-mentioned Patent Document 2, such a problem is not particularly considered.

[0012] In view of such problems, an object of the present invention is to provide a measuring device and a load detection system using the measuring device that can efficiently obtain high-precision measurement results by appropriately setting the measurement period of the electric quantity when the period until the electric quantity to be measured is saturated may vary.

[0013] Solutions for solving problems

[0014] The first aspect of the present invention relates to a measuring device. The measuring device according to this aspect comprises: a switching unit for switching between applying a voltage to a circuit and not applying a voltage; a measuring unit for measuring the electric quantity at a predetermined location in the circuit; and a control unit for controlling the switching unit and the measuring unit to measure the electric quantity that changes and becomes saturated at the predetermined location. The control unit performs the following processing: setting a plurality of different measurement periods; starting to apply the voltage synchronously with the start of each of the measurement periods; determining whether the electric quantity measured by the measuring unit in each of the measurement periods is saturated; and obtaining the measurement result of the electric quantity according to the measurement period in which the electric quantity is determined to be saturated.

[0015] According to the measuring device involved in this method, the measurement result of the electric quantity is obtained according to the measurement period in which the electric quantity as the measurement object is determined to be saturated among a plurality of different measurement periods. Therefore, even if the period until the electric quantity as the measurement object is saturated may vary, the measurement period of the electric quantity can be appropriately set, and a high-precision measurement result can be efficiently obtained.

[0016] The second aspect of the present invention relates to a load detection system. The load detection system according to this aspect comprises: a load sensor having an element portion whose electrostatic capacitance changes according to a load; a voltage applying portion including the measuring device according to the first aspect for applying a voltage to the element portion; and a signal processing portion for acquiring the electrostatic capacitance of the element portion from the measurement result of the measuring device. The measuring device performs the following processing: applying the voltage to the element portion through the switching portion; measuring the electric quantity at a predetermined position of the voltage applying portion through the measuring portion; and outputting the measurement result of the electric quantity acquired by the control portion to the signal processing portion.

[0017] According to the load detection system involved in this mode, since the measuring device involved in the first mode is used, even if the electrostatic capacitance of the component part changes according to the load, the measurement period corresponding to the electrostatic capacitance can be set. Therefore, the electric quantity corresponding to the electrostatic capacitance can be measured efficiently and accurately, and the load of the component part can be detected with high accuracy.

[0018] Effects of the Invention

[0019] As described above, according to the present invention, it is possible to provide a measuring device and a load detection system using the measuring device that can efficiently obtain high-precision measurement results by appropriately setting the measurement period of the electric quantity when the period until the electric quantity to be measured may vary.

[0020] The effects and significance 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 the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 (a) is a perspective view schematically showing a base member according to an embodiment and a conductive elastic body provided on an upper surface of the base member. Figure 1 (b) schematically shows the embodiment involved in Figure 1 (a) is a three-dimensional diagram showing a state in which a conductor line is provided in the structure.

[0022] Figure 2 (a) schematically shows the embodiment involved in Figure 1 (b) is a stereoscopic diagram of a state in which a wire is provided in the structure. Figure 2 (b) schematically shows the embodiment involved in Figure 2 A perspective view showing a state in which a sheet-like member is provided in the structure of (a).

[0023] Figure 3 (a) and Figure 3 (b) are views schematically showing cross sections of the load sensors according to the embodiments.

[0024] Figure 4 It is a plan view schematically showing the internal structure of the load sensor according to the embodiment.

[0025] Figure 5 It is a block diagram showing the structure of the load detection system according to the embodiment.

[0026] Figure 6 : is a circuit diagram showing the structure of a potential applying section according to the embodiment.

[0027] Figure 7 2 is a timing chart showing a gate signal output from a gate signal generating unit according to the embodiment.

[0028] Figure 8 It is a diagram showing an operating state of a potential applying unit when a voltage is applied to a device unit to be measured according to the embodiment.

[0029] Fig. 9 It is a diagram showing an operating state of a voltage applying unit during discharge according to the embodiment.

[0030] Fig.10 (a) to (d) are graphs showing the relationship between the current measured by the measuring unit and the measurement period according to the embodiment.

[0031] Fig.11 This is a graph showing simulation results of the relationship between the period ratio and the average current ratio when the electrostatic capacitance of the element portion to be measured according to the embodiment is a predetermined value.

[0032] Fig.12 1 is a flowchart showing a process of acquiring a measurement result of a current for a device unit to be measured according to the embodiment.

[0033] Fig.13 (a) and (b) are flowcharts respectively showing a process of determining whether or not the current is saturated during a measurement period according to the embodiment.

[0034] Fig.14 (a) and (b) are diagrams for explaining a method of determining whether or not the current is saturated during a measurement period according to Modification Example 1.

[0035] Fig.15 1 is a diagram showing a configuration of a measuring device according to Modification Example 2.

[0036] Fig.16 This is a diagram showing the flow of current when the charge accumulated in the element portion to be measured according to Modification Example 2 is discharged.

[0037] Fig.17 This is a graph showing simulation results of the relationship between the period ratio and the average current ratio when the electrostatic capacitance of the element portion to be measured according to Modification Example 2 is a predetermined value.

[0038] Fig.18 1 is a diagram showing a configuration of a measuring device according to Modification Example 3.

[0039] Fig.19(a) to (d) are graphs showing the relationship between the voltage measured by the measuring unit and the measurement period according to Modification Example 3, respectively.

[0040] Fig. 20 1 is a flowchart showing a process of acquiring a voltage measurement result for a device unit to be measured according to Modification Example 3. FIG.

[0041] Fig.21 (a) and (b) are flowcharts respectively showing a process of determining whether or not the voltage is saturated during the measurement period according to Modification Example 3.

[0042] However, the drawings are mainly for illustration and do not limit the scope of the present invention. DETAILED DESCRIPTION

[0043] The load detection system according to the present invention can be applied to management systems that perform processing according to the applied load, etc. Examples of management systems include inventory management systems, driver monitoring systems, coach management systems, safety management systems, and nursing / childcare management systems.

[0044] In the inventory management system, for example, a load sensor installed in the inventory shelf is used to detect the load of the loaded goods, thereby detecting the types and number of goods on the inventory shelf. In this way, goods can be efficiently managed in stores, factories, warehouses, etc., and manpower can be saved. In addition, a load sensor installed in a refrigerator is used to detect the load of food in the refrigerator, thereby detecting the types, number and amount of food in the refrigerator. In this way, a recipe using the food in the refrigerator can be automatically suggested.

[0045] In the driver monitoring system, for example, a load sensor provided on 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 on 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.).

[0046] 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 being able to correct or guide the foot to an appropriate walking state or running state.

[0047] In the safety management system, for example, load sensors installed on the floor are used to detect the load distribution when a person passes by, and to detect weight, stride, speed, shoe sole pattern, etc. Thus, the person passing by can be identified by comparing these detection information with the data.

[0048] In the nursing / 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, thereby estimating what actions the person intends to take at the position of the bedding and toilet seat to prevent falling.

[0049] The load detection system of the following embodiment is applied to the management system as described above, for example. The load detection system of the following embodiment comprises: a load sensor for detecting a load; and a detection unit combined with the load sensor. The load sensor of the following embodiment is an electrostatic capacitance type load sensor. Such a load sensor is sometimes also referred to as an "electrostatic capacitance type pressure sensitive sensor element", "capacitive pressure detection sensor element", "pressure sensitive switch element", etc. In addition, the following embodiment is one embodiment of the present invention, and the present invention is not limited by the following embodiment in any way.

[0050] The embodiments of the present invention are described below with reference to the drawings. For convenience, mutually orthogonal X, Y, and Z axes are marked in each drawing. The Z axis direction is the height direction of the load sensor 1.

[0051] Reference Figure 1 (a)~ Figure 4 The load sensor 1 will be described.

[0052] Figure 1 (a) is a perspective view schematically showing the base member 11 and the conductive elastic body 12 provided on the upper surface (the surface on the positive side of the Z axis) of the base member 11 .

[0053] The base member 11 is a flat plate-shaped member having elasticity and insulating properties. The base member 11 has a rectangular shape when viewed from above. The thickness of the base member 11 is constant. The thickness of the base member 11 is, for example, 0.01 mm to 2 mm. When the thickness of the base member 11 is small, the base member 11 is sometimes referred to as a sheet member or a film member. The base member 11 is made of a non-conductive resin material or a non-conductive rubber material.

[0054] The resin material used for the base member 11 is, for example, at least one resin material selected from the group consisting of styrene resins, silicone resins (e.g., polydimethylpolysiloxane (PDMS)), acrylic resins, rotaxane resins, and polyurethane resins. The rubber material used for the base member 11 is, for example, at least one rubber material selected from the group consisting of silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene-propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, polyurethane rubber, and natural rubber.

[0055] The conductive elastic body 12 is disposed on the upper surface (the surface on the positive side of the Z axis) of the base member 11. Figure 1 In (a), three conductive elastic bodies 12 are arranged on the upper surface of the base member 11. The conductive elastic body 12 is a member having elastic conductivity. Each conductive elastic body 12 has a strip shape that is long in the Y-axis direction. The three conductive elastic bodies 12 are arranged at a predetermined interval in the X-axis direction. A wiring W2 electrically connected to the conductive elastic body 12 is provided at the end of each conductive elastic body 12 on the negative side of the Y-axis.

[0056] The conductive elastic body 12 is formed on the upper surface of the base member 11 by printing methods such as screen printing, gravure printing, flexographic printing, offset printing, and gravure offset printing. According to these printing methods, the conductive elastic body 12 can be formed on the upper surface of the base member 11 with a thickness of about 0.001 mm to 0.5 mm.

[0057] The conductive elastic body 12 is composed of a resin material and conductive fillers dispersed therein, or a rubber material and conductive fillers dispersed therein.

[0058] The resin material used for the conductive elastomer 12 is similar to the resin material used for the base member 11 described above, and is, for example, at least one resin material selected from the group consisting of styrene resins, silicone resins (polydimethylpolysiloxane (such as PDMS)), acrylic resins, rotaxane resins, and polyurethane resins.

[0059] The rubber material used for the conductive elastomer 12 is the same as the rubber material used for the base member 11 mentioned above, 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.

[0060] The conductive filler used for the conductive elastomer 12 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, metal wires (in fiber state) and other conductive fibers.

[0061] Figure 1 (b) is a schematic diagram showing Figure 1 (a) is a perspective view showing a state in which a conductor wire 13 is provided in the structure.

[0062] The conductor wire 13 is a linear member, which is superimposed on Figure 1 In the present embodiment, three conductor wires 13 are arranged on the upper surface of the three conductive elastic bodies 12 in a superimposed manner. The three conductor wires 13 are arranged at predetermined intervals along the long side direction (Y-axis direction) of the conductive elastic body 12 in a manner that crosses the conductive elastic body 12. Each conductor wire 13 is arranged to extend along the X-axis direction in a manner that crosses the three conductive elastic bodies 12.

[0063] The conductor wire 13 is, for example, a copper wire with a coating. The conductor wire 13 is composed of a linear conductive member 13a and a dielectric 13b formed on the surface of the conductive member 13a. Figure 3 (a) and (b) are described below.

[0064] Figure 2 (a) is a schematic diagram showing Figure 1 (b) is a three-dimensional view of a state in which the wire 14 is provided in the structure.

[0065] In such Figure 1 After the conductor wires 13 are arranged as in (b), each conductor wire 13 is connected to the base member 11 by the wire 14 so as to be movable along the longitudinal direction (X-axis direction) of the conductor wire 13. Figure 2 In the example shown in (a), twelve wires 14 connect the conductor wire 13 and the base member 11 at positions other than the positions where the conductive elastic body 12 overlaps the conductor wire 13. The wire 14 is made of chemical fiber, natural fiber, or a mixed fiber thereof.

[0066] Figure 2 (b) is schematically shown in Figure 2 (a) is a perspective view showing a state in which a base member 15 is provided in the structure.

[0067] from Figure 2 A base member 15 is provided above the structure shown in (a) (positive side of the Z axis). The base member 15 is an insulating member. The base member 15 is, for example, at least one resin material selected from a group consisting of polyethylene terephthalate, polycarbonate, and polyimide. The base member 15 may also be made of the same material as the base member 11. The base member 15 has a flat plate shape parallel to the XY plane, and has the same size and shape as the base member 11 when viewed from above. The thickness of the base member 15 in the Z-axis direction is, for example, 0.01 mm to 2 mm.

[0068] The outer circumference of the base member 15 is connected to the outer circumference of the base member 11 by a silicone rubber adhesive, a wire, etc. Thus, the base member 15 is fixed to the base member 11. The conductor wire 13 is sandwiched between the conductive elastic body 12 and the base member 15. Figure 2 The load sensor 1 is completed as shown in (b). The load sensor 1 can be Figure 2 The state (b) is used after the front and back sides are reversed.

[0069] Figure 3 (a) and Figure 3 (b) is a diagram schematically showing a cross section of the load sensor 1 when the load sensor 1 is cut along a plane parallel to the YZ plane at the center position of the conductive elastic body 12 in the X-axis direction. Figure 3 (a) shows a state where no load is applied, Figure 3 (b) shows a state where a load is applied.

[0070] like Figure 3 As shown in (a) and (b), the conductor wire 13 is composed of a conductive member 13a and a dielectric 13b formed on the conductive member 13a. The conductive member 13a is a linear member having conductivity. The dielectric 13b covers the surface of the conductive member 13a. The conductive member 13a is composed of, for example, copper. The diameter of the conductive member 13a is, for example, about 60 μm.

[0071] The dielectric 13b has electrical insulation properties and is made of, for example, a resin material, a ceramic material, a metal oxide material, etc. The dielectric 13b 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. The dielectric 13b is formed at least in the range of the conductor line 13 that overlaps with the conductive elastic body 12.

[0072] like Figure 3 As shown in (a), when no load is applied, the force applied between the conductive elastic body 12 and the conductor wire 13 and the force applied between the base member 15 and the conductor wire 13 are substantially zero. Figure 3 When a load is applied to the surface on the negative side of the Z axis of the base member 11 as shown in (b), the conductive elastic body 12 and the base member 11 are deformed by the conductor wire 13 .

[0073] like Figure 3As shown in (b), the conductor wire 13 approaches the conductive elastic body 12 in a manner surrounded by the conductive elastic body 12 due to the application of the load. Along with this, the contact area between the conductor wire 13 and the conductive elastic body 12 increases. As a result, the electrostatic capacitance between the conductive member 13a and the conductive elastic body 12 changes. By detecting the electrostatic capacitance between the conductive member 13a and the conductive elastic body 12, the load applied to the area is obtained.

[0074] Figure 4 FIG. 1 is a top view schematically showing the internal structure of the load sensor 1. Figure 4 In the figure, for convenience, illustration of the wire 14 and the base member 15 is omitted.

[0075] like Figure 4 As shown, element portions A11, A12, A13, A21, A22, A23, A31, A32, and A33 whose electrostatic capacitance varies according to the load are formed at the positions where the three conductive elastic bodies 12 intersect the three conductor lines 13. Each element portion includes the conductive elastic body 12 and the conductor line 13 near the intersection of the conductive elastic body 12 and the conductor line 13.

[0076] In each element portion, the conductor line 13 constitutes one electrode (eg, anode) of the electrostatic capacitor, and the conductive elastic body 12 constitutes the other electrode (eg, cathode) of the electrostatic capacitor. Figure 3 (a), (b)) constitute one electrode of the load sensor 1 (capacitive load sensor), the conductive elastic body 12 constitutes the other electrode of the load sensor 1 (capacitive load sensor), and the dielectric 13b (refer to Figure 3 (a) and (b) of FIG. 1 correspond to the dielectric that defines the capacitance in the load sensor 1 (capacitive load sensor).

[0077] When a load is applied to each element portion in the Z-axis direction, the conductor wire 13 is wrapped by the conductive elastic body 12. As a result, the contact area between the conductor wire 13 and the conductive elastic body 12 changes, and the electrostatic capacitance between the conductor wire 13 and the conductive elastic body 12 changes. The end of the conductor wire 13 on the negative side of the X-axis and the end of the wiring W2 on the negative side of the Y-axis provided on the conductive elastic body 12 are aligned with the reference Figure 5 It is connected to the detection unit 2 described later.

[0078] If a load is applied to the element portion A11, the contact area between the conductive member 13a of the conductor wire 13 and the conductive elastic body 12 via the dielectric 13b in the element portion A11 increases. In this case, the load applied to the element portion A11 can be calculated by detecting the electrostatic capacitance between the conductive elastic body 12 closest to the negative side of the X-axis and the conductor wire 13 closest to the positive side of the Y-axis. Similarly, in other element portions, the load applied to the other element portions can be calculated by detecting the electrostatic capacitance between the conductive elastic body 12 and the conductor wire 13 intersecting in the other element portions.

[0079] Figure 5 3 is a block diagram showing the structure of the load detection system 3 .

[0080] The load detection system 3 includes the load sensor 1 and the detection unit 2. The detection unit 2 detects the electrostatic capacitance of each element of the load sensor 1. As described above, the electrostatic capacitance of each element changes according to the load applied to each element. The detection unit 2 applies a voltage to each element to detect the electrostatic capacitance of each element that changes according to the load.

[0081] The detection unit 2 includes a voltage application unit 100 , a measurement device 200 , and a signal processing unit 300 . The measurement device 200 is included in the voltage application unit 100 .

[0082] The voltage applying unit 100 applies a predetermined potential to two electrodes of each element unit, and applies a voltage corresponding to the potential difference between these potentials to each element unit. The voltage applying unit 100 includes a potential generating unit 110, a first switching unit 120, and a second switching unit 130. The potential generating unit 110 generates a potential to be applied to two electrodes of each element unit. The first switching unit 120 selectively applies the potential generated by the potential generating unit 110 to the three conductor wires 13 of the load sensor 1. The first switching unit 120 selectively applies the potential generated by the potential generating unit 110 to the three conductive elastic bodies 12 of the load sensor 1.

[0083] The measuring device 200 measures the electric quantity corresponding to the amount of charge accumulated in the element portion by the application of the voltage. Here, as the electric quantity, the measuring device 200 measures the supply line L0 (refer to Figure 6 ) current.

[0084] The signal processing unit 300 is composed of a microcomputer or the like. The signal processing unit 300 controls the first switching unit 120 and the second switching unit 130 to apply the potential generated by the potential generating unit 110 to a predetermined element portion of the load sensor 1. Then, the signal processing unit 300 acquires the measured value of the current measured by the measuring device 200 from the measuring device 200 according to the application of the potential, and detects the electrostatic capacitance of each element portion based on the acquired measured value.

[0085] Figure 6 is a circuit diagram showing the structure of the voltage applying unit 100 .

[0086] The voltage applying unit 100 includes a potential generating unit 110, a first switching unit 120, and a second switching unit 130. The potential generating unit 110 includes a measuring device 200 and an equipotential generating unit 111. The potential generating unit 110 generates a potential to be applied to the element unit of the load sensor 1 through the measuring device 200 and the equipotential generating unit 111.

[0087] The measuring device 200 includes a control unit 201, a switching unit 202, and a measuring unit 203. The control unit 201 is composed of a microcomputer, an FPGA, etc. The control unit 201 controls the switching unit 202 and the measuring unit 203 to measure the current (electricity) that changes and saturates in the supply line L0. The switching unit 202 is used to switch between applying the power supply potential Vdd to the supply line L1 and not applying the power supply potential Vdd. The switching unit 202 has switch elements 202a and 202b connected in series between the supply line L1 and the ground line L3.

[0088] The measuring unit 203 includes a resistor inserted into the supply line L0 and measures the current flowing through the supply line L0. That is, when the switch element 202a is in the conducting state and the switch element 202b is in the non-conducting state, the measuring unit 203 measures the current flowing through the supply line L0, that is, the current corresponding to the amount of charge transferred to the load sensor 1 via the supply lines L0 and L1 and the first switching unit 120. The measuring unit 203 may be arranged at another position on the path from the power supply S1 to the multiplexer 122 via the switch element 202a.

[0089] When measuring the current, the control unit 201 outputs a gate signal for turning on the switch elements 202a and 202b. The switch element 202a is composed of a P-type FET and is turned on by applying a low-level gate signal to the gate. The switch element 202b is composed of an N-type FET and is turned on by applying a high-level gate signal to the gate.

[0090] Figure 7 1 is a timing chart showing gate signals output from the control unit 201 to the switching elements 202 a and 202 b when measuring the current of the element unit to be measured.

[0091] The upper gate signal G1 is a signal supplied to the gate of the switching element 202a, and the lower gate signal G2 is a signal supplied to the gate of the switching element 202b.

[0092] like Figure 7As shown, when measuring the current of an element part set as the measurement object, the control unit 201 outputs multiple gate signals G1 with different periods T1(n) (n is a positive natural number) to the gate of the switching element 202a. The period T1(n) becomes longer as the variable n increases. The gate signal G1 of each period T1(n) is at a low level during the period Ta(n) and at a high level during other periods. The ratio (duty cycle) of the period Ta(n) to the period T1(n) is fixed. This ratio (duty cycle) is, for example, 50%. Therefore, the periods Ta(n) of the multiple gate signals G1 are different from each other. The period Ta(n) of each gate signal G1 becomes longer as the variable n increases.

[0093] In addition, when detecting the electrostatic capacitance of an element part, the control unit 201 outputs multiple gate signals G2 with different periods T2(n) (n is a positive natural number) to the gate of the switching element 202b. The period T2(n) becomes longer as the variable n increases. The gate signal G2 of each period T2(n) is at a high level during the period Tb(n) and at a low level during other periods. The ratio (duty cycle) of the period Tb(n) to the period T2(n) is fixed. This ratio (duty cycle) is, for example, 50%. Therefore, the periods Tb(n) of the multiple gate signals G2 are different from each other. The period Tb(n) in each gate signal G2 becomes longer as the variable n increases.

[0094] The period T1(n) of the gate signal G2 is the same length as the period T1(n) of the gate signal G1, and the period Tb(n) of the gate signal G2 is the same length as the period Ta(n) of the gate signal G1. In addition, the period Tb(n) of the gate signal G2 is output at a timing that falls roughly in the middle of the high level period of the period T1(n+1) of the gate signal G1. Therefore, a predetermined time interval (time gap) is generated between the end timing of the period Ta(n) and the start timing of the period Tb(n), and a predetermined time interval is generated between the end timing of the period Tb(n) and the start timing of the period Ta(n+1).

[0095] During the period Ta(n), the switch element 202a is turned on, and the power supply potential Vdd is applied to the element portion to be measured. That is, the control unit 201 starts applying the power supply potential Vdd in synchronization with the start of the period Ta(n). During this period Ta(n), the control unit 201 causes the measurement unit 203 to measure the current flowing through the supply line L0. Therefore, the period Ta(n) corresponds to the current measurement period. In this way, when measuring the current of the element portion to be measured, the control unit 201 sets a plurality of different measurement periods to measure the current flowing through the supply line L0.

[0096] In the period Tb(n), the switch element 202b is turned on, and the element portion to be measured is discharged. That is, the charge accumulated in the element portion to be measured by the application of the power supply potential Vdd in the period Ta(n) is discharged to the ground line L3 due to the conduction of the switch element 202b in the next period Tb(n). Then, in the next period Ta(n+1), the element portion to be measured is charged again, and the current is measured. Thereafter, the same process is repeated, and the current is measured for each period Ta(n).

[0097] In addition, Figure 7 , six periods T1(n) and five periods T2(n) are shown, but periods T1(6) and T2(5) are followed by periods T1(n) and T2(n). These periods T1(n) and T2(n) also become longer as the variable n increases, as described above.

[0098] Return to Figure 6 The equipotential generating unit 111 is an operational amplifier for generating a potential equal to the potential of the supply line L1 and applying the potential to the supply line L1.

[0099] The first switching unit 120 selectively connects one of the supply line L1 and the ground line L3 to the wiring W1 respectively extended from the plurality of conductor lines 13 (conductive members 13 a ).

[0100] Specifically, the first switching unit 120 includes three multiplexers 121 and one multiplexer 122. The supply line L1 is connected to the input terminal of the multiplexer 122. The multiplexer 122 has three output terminals. The three multiplexers 121 are connected to the three output terminals of the multiplexer 122, respectively. The three multiplexers 121 are provided corresponding to the three conductor wires 13 (conductive members 13a), respectively. The conductive members 13a (wiring W1) of the conductor wire 13 are connected to the output terminals of each multiplexer 121.

[0101] Each multiplexer 121 has two input terminals. Multiplexer 122 is connected to one input terminal of multiplexer 121, and a power supply potential Vdd is applied to the input terminal via supply line L1. Power supply potential Vdd is a potential generated by power supply S1. The other input terminal of multiplexer 121 is connected to ground line L3.

[0102] The second switching unit 130 selectively connects one of the supply line L2 and the ground line L3 to the conductive elastic body 12 (wiring W2 ).

[0103] Specifically, the second switching unit 130 includes three multiplexers 131. The three multiplexers 131 are provided corresponding to the three conductive elastic bodies 12, respectively. The wiring W2 connected to the conductive elastic body 12 is connected to the output side terminal of each multiplexer 131. Each multiplexer 131 is provided with two input side terminals. The supply line L2 is connected to one input side terminal of the multiplexer 131. The ground line L3 is connected to the other input side terminal of the multiplexer 131.

[0104] The first switching unit 120 and the second switching unit 130 are composed of Figure 5 The signal processing unit 300 controls the three conductor wires 13 (wiring W1) and the three conductive elastic bodies 12 (wiring W2). As a result, the power supply potential Vdd, the potential from the equipotential generating unit 111, or the ground potential is applied to the three conductor wires 13 (wiring W1) and the three conductive elastic bodies 12 (wiring W2).

[0105] Figure 8 1 is a diagram showing a state of the voltage applying unit 100 when a voltage is applied to a device unit to be measured.

[0106] Here, Figure 6 The component part A11 of is set as the measurement object. Figure 8 In FIG. 1 , a thick solid line shows a path for applying a potential equivalent to the power supply potential Vdd to the load sensor 1 , and a thick dotted line shows a path for applying a ground potential.

[0107] When the capacitance detection target is the element unit A11, the multiplexers 121 and 122 of the first switching unit 120 and the multiplexer 131 of the second switching unit 130 are set to Figure 6 In this state, if Figure 7 The gate signals G1 and G2 are used to switch the switch element 202a to the on state. Figure 8 As shown, the power supply potential Vdd is applied to the conductor line 13 of the row including the element portion A11 of the load sensor 1. Thus, the power supply potential Vdd is applied to one electrode (conductor line 13) of the three element portions A11 to A13 of the row.

[0108] At this time, regarding the other electrodes (three conductive elastic bodies 12) of the three element parts A11 to A13, only the other electrode of element part A11 is connected to the ground via the second switching part 130, and the other electrode of the remaining element part A12 is connected to the supply line L2. Therefore, different potentials are applied to the two electrodes of element part A11 among these element parts A11 to A13, and the same potential is applied to element parts A12 and A13 among these element parts A11 to A13. Therefore, charge is accumulated in element part A11, and no charge is accumulated in element parts A12 and A13. Element parts other than element parts A11 to A13 do not accumulate charge because one electrode (conductor line 13) is open. Therefore, in Figure 8 In this state, the element part A11 is mainly charged (charge is accumulated).

[0109] During this charging, the current Im flowing through the supply line L0 is measured by the measuring unit 203. The current Im is Figure 7 The control unit 201 calculates the average current value Im_av of the current Im based on the measurement value of the measuring device 200 .

[0110] Thus, when the period Ta(n) ends, the switch element 202a becomes non-conductive, and the application of the power supply potential Vdd to the supply line L1 is cut off. Figure 7 When the period Tb(n) arrives, the switch element 202b is turned on to discharge the element portion A11.

[0111] Fig. 9 1 is a diagram showing a state of the voltage applying unit 100 when discharging the element unit to be measured.

[0112] exist Fig. 9 In FIG. 1 , the thick solid line shows the path of the current flowing toward the ground.

[0113] like Fig. 9 As shown by the dotted arrow, the current flows from the supply line L1 to the ground line L3, and the charge charged to the element part A11 is discharged to the ground. In this way, when the period Tb(n) ends, the switch element 202b is non-conductive, and the connection between the ground line L3 and the supply line L1 is cut off. Then, when the next period Ta(n+1) comes, Figure 8 In the same manner as in the case of , the power supply potential Vdd of the supply line L1 is applied to the element portion A11. After that, due to the arrival of the period Tb(n+1), Fig. 9 In the same manner as in the case of , the element portion A11 is discharged. In this way, the charging and discharging of the element portion A11 are repeated.

[0114] Fig.10(a) to (d) are graphs showing the relationship between the current Im measured by the measuring unit 203 and the measurement period.

[0115] Fig.10 (a) and (b) show graphs when the load applied to the element portion A11 to be measured is small. Fig.10 (c) and (d) show graphs when the load applied to the element portion A11 to be measured is large. Fig.10 (a) and (c) show the relationship between the period Ta(n) and the current Im. Fig.10 (b) and (d) show the relationship between the next period Ta(n+1) and the current Im.

[0116] like Fig.10 As shown in (a) and (b), when the load applied to the element part A11 is small, the electrostatic capacitance of the element part A11 is small, so the period until the current Im is saturated (the period from when the current Im starts to flow to when it converges to zero) is short. Therefore, the current Im is saturated within the range of the periods Ta(n) and Ta(n+1). In this case, when the average current values ​​Im_av(n) and Im_av(n+1) are calculated for the periods T1(n) and T1(n+1), the following relationship is satisfied.

[0117] Im_av(n) / Im_av(n+1)=Ta(n+1) / Ta(n)…(1)

[0118] In addition, the average current values ​​Im_av(n) and Im_av(n+1) can also be calculated for the periods Ta(n) and Ta(n+1). In this case, the relationship of the above formula (1) is also satisfied. In addition, since the ratio (duty cycle) of Ta(n) and T1(n) is the same as the ratio of Ta(n+1) and T1(n+1), the right side of the above formula (1) is satisfied even if it is T1(n+1) / T1(n) instead of Ta(n+1) / Ta(a).

[0119] like Fig.10 As shown in (c) and (d), when the load applied to the element part A11 is large, the electrostatic capacitance of the element part A11 is large, so the period until the current Im is saturated (the period from when the current Im starts to flow until it converges to zero) is long. Therefore, the current Im is not saturated within the range of the period Ta(n) and Ta(n+1), and the relationship of the above formula (1) is not satisfied. Then, the variable n is greater than Fig.10In the case of (c) and (d), the variable n is large, and the period until the current Im is saturated is less than the period Ta(n), thereby satisfying the relationship of the above formula (1). Therefore, it is possible to determine whether the current Im is saturated within the range of the period Ta(n) as the measurement period based on whether the relationship of the above formula (1) is satisfied.

[0120] Fig.11 This is a graph showing simulation results of the relationship between the ratio of periods T1(n) and T1(n+1) (cycle ratio) and the ratio of average current values ​​Im_av(n) and Im_av(n+1) (average current ratio) when the electrostatic capacitance of the component part being measured is a specified value.

[0121] exist Fig.11 In the simulation results, the horizontal axis is set to the period ratio T1(n+1) / T1(n), but the same simulation results are obtained even if the horizontal axis is the measurement period ratio Ta(n+1) / Ta(n). That is, Fig.11 The simulation result is equivalent to the case where the horizontal axis is the measurement period ratio Ta(n+1) / Ta(n).

[0122] like Fig.11 As shown, in this simulation, in the range of the period ratio less than 1.1, the relationship between the period ratio and the average current ratio does not satisfy linearity. This corresponds to the relationship of the above formula (1) not being satisfied in this range. This is because, in this range, Fig.10 As in (c) and (d) of FIG. 1 , the period until the current Im is saturated is longer than the period Ta(n).

[0123] In contrast, within the range where the cycle ratio is greater than 1.1, the relationship between the cycle ratio and the average current ratio satisfies linearity. This corresponds to the relationship satisfying the above equation (1) within this range. This is because within this range, Fig.10 As in (a) and (b), the period until the current Im is saturated is less than the period Ta(n).

[0124] In this way, it can be confirmed that whether the current Im is saturated within the range of the period Ta(n) as the measurement period can be determined based on whether the relationship between the cycle ratio and the average current ratio satisfies linearity, that is, whether the relationship of the above formula (1) is satisfied. Therefore, by using the period Ta(n) within the range within which the relationship between the cycle ratio and the average current ratio satisfies linearity, that is, the range within which the relationship of the above formula (1) is satisfied as the appropriate measurement period of the current Im, the current Im from the start of the flow of the current Im to saturation can be measured, and the average current value Im_av based on the saturated current amount can be appropriately obtained.

[0125] Fig.12 1 is a flowchart showing a process of acquiring a measurement result of a current Im for a device unit to be measured.

[0126] The component part to be measured is Figure 6 In the case of the element unit A11, the first switching unit 120 and the second switching unit 130 are set to Figure 6 In this state, the discharge of all the elements of the load sensor 1 is completed. Then, the control unit 201 of the measuring device 200 starts Figure 7 The gate signals G1 and G2 are output to execute Fig.12 processing.

[0127] The control unit 201 sets 1 to the variable n (S11), and obtains the measured value of the current Im in the period Ta(n) from the measuring unit 203 (S12). When the measurement of the current Im in the period Ta(n) is completed, the control unit 201 determines whether the current Im is saturated (whether the current is converged to zero) in the period Ta(n) based on the obtained measured value of the current Im (S13). If the determination in step S13 is "No", the control unit 201 adds 1 to the variable n (S15), and returns the process to step S12. Thus, the control unit 201 obtains the measured value of the current Im in the next period Ta(n) (S12), and determines whether the current Im is saturated in the period Ta(n) based on the obtained measured value (S13).

[0128] The control unit 201 performs the same process while increasing the variable n until the determination of step S13 is "yes". Then, if the determination of step S13 is "yes", the control unit 201 outputs the measurement result of the current Im measured during the period Ta(n) at this time to the signal processing unit 300, and ends the output of the gate signals G1 and G2 (S14). Thus, the control unit 201 ends Fig.12 processing.

[0129] Fig.13 (a) shows Fig.12 Flowchart of the processing in step S13.

[0130] The control unit 201 calculates the average current value Im_av(n) of the current Im based on the current Im acquired in the period Ta(n) (S101). The control unit 201 refers to the change rate Im_av(n-1) / Im_av(n) between the average current value Im_av(n) and the average current value Im_av(n-1) calculated for the previous period Ta(n-1), and the change rate Ta(n) / Ta(n-1) between the period Ta(n) and the previous period Ta(n-1) (S102), to determine whether the relationship between the two change rates substantially satisfies linearity (S103).

[0131] The determination in step S103 is similar to the above formula (1) based on whether the change rate Im_av(n-1) / Im_av(n) and the change rate Ta(n) / Ta(n-1) are substantially equal, for example, whether the difference between the two change rates is within a few %.

[0132] Furthermore, when the two change rates remain substantially equal while the variable n is increased several times (eg, five times), the determination in step S103 may be “Yes.” This makes it possible to more accurately determine that the current Im is saturated in the period Ta(n).

[0133] If the determination in step S103 is "yes", the control unit 201 determines that the current is saturated in the period Ta(n) (S104), and Fig.12 On the other hand, if the determination of step S103 is "No", the control unit 201 skips step S104 and sets Fig.12 The determination of step S13 is set to "No". Thus, the control unit 201 ends Fig.13 (a) processing.

[0134] exist Fig.12 In step S13, Fig.13 In the case of the processing of (a), the control unit 201 outputs the value obtained by multiplying the average current value Im_av(n) when the answer to step S103 is "Yes" by the period T1(n), that is, the charge amount Qm(n) accumulated in the element unit A11 as the measurement object, as the measurement result in step S14 to the signal processing unit 300. In this case, the signal processing unit 300 calculates the electrostatic capacitance C of the element unit A11 by the following formula.

[0135] C=Qm(n) / Vdd…(2)

[0136] Alternatively, the control unit 201 may output the average current value Im_av(n) when step S103 is "yes" and the period T1(n) at this time as the measurement result to the signal processing unit 300. In this case, the signal processing unit 300 obtains the charge amount Qm(n) based on the received average current value Im_av(n) and the period T1(n), and calculates the electrostatic capacitance based on the above formula (2).

[0137] exist Fig.12In the process, the greater the load applied to the component part A11, that is, the greater the electrostatic capacitance of the component part A11, the more steps S12, S13, and S15 are repeated. However, when the period Ta(n) suitable for the size of the electrostatic capacitance of the component part A11 is reached, the judgment of step S13 becomes "yes", and the process of a period Ta(n) longer than this period is not performed. Therefore, it is possible to obtain efficient and high-precision measurement results by using the period Ta(n) suitable for the component part A11.

[0138] In addition, Fig.12 In step S13, the processing may also be Fig.13 (b) is processed. In this case, the control unit 201 accumulates all the current values ​​obtained during the period Ta(n) to calculate the total current value Im_sum(n) (S111), and determines whether the calculated total current value Im_sum(n) substantially converges to a constant (S112). In step S112, the control unit 201 determines whether the difference between the total current value Im_sum(n) calculated this time and the total current value Im_sum(n-1) calculated last time is within the error range. Alternatively, in step S112, the control unit 201 determines whether the ratio of the total current value Im_sum(n) calculated this time to the total current value Im_sum(n-1) calculated last time is within the error range centered on 1.

[0139] In this case, when the difference or ratio is maintained within the error range while the variable n is increased several times (e.g., five times), the determination in step S112 may be set to "yes." This makes it possible to more accurately determine that the current Im is saturated during the period Ta(n).

[0140] In this case, the total current value Im_sum(n) calculated in step S111 is the amount of charge accumulated in the element portion A11 during the period Ta(n). Fig.12 In step S13, Fig.13 In the case of the processing of (b), the control unit 201 only needs to output the total current value Im_sum(n) when step S112 is "yes" as the measurement result in step S14 to the signal processing unit 300. In this case, the signal processing unit 300 applies the acquired total current value Im_sum(n) as Qm(n) to equation (2) to calculate the electrostatic capacitance C of the element unit A11.

[0141] According to the above processing, when the capacitance of the element unit A11 to be measured is obtained, the signal processing unit 300 switches the element unit A11 to be measured to the next element unit. For example, the first switching unit 120 and the second switching unit 130 are set so that when the next element unit to be measured is Figure 6 In the case of the element part A12, only the power supply potential Vdd and the ground potential are applied to the two electrodes of the element part A12. Specifically, the multiplexers 131 at the left and right ends of the second switching part 130 are connected to the supply line L2, and the multiplexer 131 at the center is connected to the ground line L3. The connection state of the first switching part 120 is maintained Figure 6 status.

[0142] In this state, the control unit 201 executes Fig.12 The measurement result of the current Im is output to the signal processing unit 300. Thus, the measurement result corresponding to the electrostatic capacitance of the element unit A12 is output from the control unit 201 to the signal processing unit 300. The signal processing unit 300 applies the acquired measurement result to the above formula (2) to calculate the electrostatic capacitance of the element unit A12. Next, similarly, the element unit to be measured is switched at any time while executing Fig.12 The electrostatic capacitance is calculated for all component parts in sequence.

[0143] <Effects of Implementation Methods>

[0144] According to the above-described embodiment, the following effects can be achieved.

[0145] like Fig.12 As shown, the measurement result of the current Im (electricity) is obtained from the period Ta(n) (measurement period) in which the current Im (electricity) to be measured is determined to be saturated among a plurality of different periods Ta(n) (measurement period) (S13, S14). Therefore, even if the period until the current Im (electricity) to be measured is saturated may vary, the measurement period of the current Im (electricity) can be appropriately set. Therefore, it is possible to efficiently obtain high-precision measurement results.

[0146] like Figure 7 As shown in FIG. 1 , the control unit 201 changes the lengths of a plurality of periods Ta(n) (measurement periods) in sequence in one direction. Fig.13 As shown in (a), the control unit 201 calculates the average value of the current Im (electricity) for each period Ta(n) (measurement period), that is, the average current value Im_av(n) (S101), and determines whether the current Im (electricity) is saturated (S104) based on whether the change rate of the period Ta(n) (measurement period) and the change rate of the average current value Im_av(n) substantially satisfy linearity (S103). Therefore, as shown in FIG. Fig.10 (a)~(d) and Fig.11As described above, it is possible to accurately determine whether the current Im (electric quantity) is saturated in the period Ta(n) (measurement period). Furthermore, the average current value Im_av(n) when the determination in step S103 is "yes" can be used for calculation of the electrostatic capacitance based on equation (2).

[0147] like Figure 7 As shown in FIG. 1 , the control unit 201 changes the lengths of a plurality of periods Ta(n) (measurement periods) in sequence in one direction. Fig.13 As shown in (b), the control unit 201 determines whether the current Im (electricity) is saturated (S113) based on whether the sum of the current Im (electricity) obtained in each period Ta (n) (measurement period), that is, the total current value Im_sum (n), substantially converges to a constant (S112). Through this processing, it is also possible to appropriately determine whether the current Im (electricity) is saturated in the period Ta (n) (measurement period). In addition, the total current value Im_sum (n) when the judgment of step S112 is "yes" can be used for the calculation of the electrostatic capacitance based on formula (2).

[0148] like Figure 7 As shown, the control unit 201 increases the length of multiple periods Ta(n) (measurement period) in sequence. As a result, the period Ta(n) (measurement period) can be gradually brought close to the length of the current Im (electricity) saturation. Therefore, the appropriate period Ta(n) (measurement period) can be smoothly set.

[0149] like Figure 8 As shown, the measuring device 200 measures the current flowing through the supply line L0 (the predetermined part of the voltage applying unit) when the power supply potential Vdd is applied as the amount of electricity that changes due to the charging of the element unit. As a result, the period Ta(n) (measurement period) corresponding to the change in the current Im can be appropriately set, and the measurement result of the current Im corresponding to the charge amount of the element unit as the measurement object can be obtained with high accuracy. Therefore, the electrostatic capacitance of the element unit as the measurement object can be appropriately obtained based on the measurement result.

[0150] like Figure 6 As shown, the load sensor 1 has a plurality of component parts, the voltage applying part 100 is configured to be able to switch the component part to which the voltage is applied, the signal processing part 300 controls the voltage applying part 100 to apply the voltage to each component part, obtains the measurement result from the measuring device 200 for each component part, and obtains the electrostatic capacitance of each component part from the obtained measurement result. According to this structure, since a plurality of component parts are configured, the detection range of the load can be expanded. In addition, since the above-mentioned processing is performed on each component part, the electrostatic capacitance given to each component part can be detected with high accuracy, and the load of each component part can be detected efficiently.

[0151] like Figure 6 As shown, a plurality of element parts are arranged in a matrix in a manner of arranging a plurality of rows and columns, one of the two electrodes of the element parts of the same row is connected to each other, and the other of the two electrodes of the element parts of the same column is connected to each other, and the voltage applying part 100 has multiplexers 121, 122, 131 (switching elements) for switching the rows and columns to which the potential is to be applied. According to this structure, since a plurality of element parts are arranged in a matrix, the distribution of the load extending in a square range can be detected by these element parts. In addition, by switching the rows and columns to which the potential is to be applied using the multiplexers 121, 122, 131 (switching elements), it is possible to selectively apply a voltage to the element part located at the intersection of the switched rows and columns, and the electrostatic capacitance of the element part can be efficiently detected by the above-mentioned control.

[0152] In addition, Fig.12 In the processing, it is also possible that before the variable n reaches the specified upper limit value, the determination of step S13 is not "yes", that is, before the variable n reaches the upper limit value, Fig.13 In the process of (a), the rate of change during the measurement period and the rate of change of the average current value do not substantially satisfy linearity, or Fig.13 If the total current value is not substantially constant in the process of (b), it is determined that there is a possibility that a fault has occurred in the load sensor 1 or its component. That is, the correlation between the rate of change during the measurement and the rate of change of the average current value or the total current value can also be used for fault diagnosis of the load sensor 1 or its component.

[0153] <Change Example 1>

[0154] In the above embodiment, by Fig.13 (a) or Fig.13 In the process of (b), it is determined whether the current Im converges during the period Ta(n) (measurement period), but the method of determining whether the current Im converges during the period Ta(n) (measurement period) is not limited to this. For example, it is also possible to determine whether the current Im converges during the period Ta(n) (measurement period) based on whether the current value Im_E measured by the measuring unit 203 at the end timing of the period Ta(n) (measurement period) is substantially zero.

[0155] In this case, for example, Fig.14 As shown in (a) and (b), whether the current Im has converged in the period Ta(n) is determined by whether the current value Im_E is less than the threshold value Th1. The threshold value Th1 is set to a value slightly higher than the noise component that may be generated after the current Im has converged.

[0156] like Fig.14As shown in (a), when the load applied to the element portion to be measured is small and the period until the current Im converges is shorter than the period Ta(n), the current value Im_E is smaller than the threshold value Th1. Fig.14 As shown in (b), when the load applied to the element unit to be measured is large and the period until the current Im converges is longer than the period Ta(n), the current value Im_E is greater than the threshold value Th1. Therefore, it is possible to appropriately determine whether the current Im converges during the period Ta(n) (measurement period) based on whether the current value Im_E measured by the measuring unit 203 at the end timing of the period Ta(n) is less than the threshold value Th1 (whether it is substantially zero).

[0157] <Change Example 2>

[0158] In the above embodiment, the measuring unit 203 measures the current Im that changes when the element unit to be measured is charged. However, the measuring unit 203 may measure the current that changes when the element unit to be measured is discharged.

[0159] Fig.15 2 is a diagram showing the configuration of the measurement device 200 in this case.

[0160] exist Fig.15 In the structure of FIG. 1 , a measuring unit 203 is arranged in the path between the switching element 202b and the ground line L3. The measuring unit 203 measures the current Im flowing through the path between the switching element 202b and the ground line L3 when the element unit is discharged. The measuring unit 203 may be arranged at another position on the path connected to the ground line L3 from the multiplexer 122 via the switching element 202b.

[0161] Fig.16 This is a diagram showing the flow of current when the charge accumulated in the element portion A11 is discharged.

[0162] Fig.16 The state of the voltage applying unit 100 in the embodiment is different from that of the measuring unit 203 except for the configuration position of the measuring unit 203. Fig. 9 When the switch element 202a is in a non-conductive state and the switch element 202b is in a conductive state, the measuring unit 203 measures the current flowing from the element unit A11 to the ground line L3, that is, the current Im corresponding to the amount of charge accumulated in the element unit A11 before discharge.

[0163] In Modification Example 2, since the current during discharge is measured, Figure 7 The period Tb(n) is the measurement period of the current Im. In this case, in the current Im, Fig.10Similarly, the period from the start of discharge to the saturation of the current Im (the period until the current Im converges to zero) varies according to the load applied to the element portion A11 as the measurement object, that is, the electrostatic capacitance of the element portion A11. Therefore, this period may be longer than the period Tb(n). Therefore, in the second modification, the situation that satisfies the above formula (1) and the situation that does not satisfy the above formula (1) are also generated according to the magnitude relationship between the period from the start of discharge to the saturation of the current Im and the period Tb(n).

[0164] Fig.17 This is a graph showing the simulation results of the relationship between the ratio of the periods T2(n) and T2(n+1) (cycle ratio) and the ratio of the average current values ​​Im_av(n) and Im_av(n+1) (average current ratio) when the electrostatic capacitance of the component part being measured is a specified value.

[0165] exist Fig.17 In the figure, the average current values ​​Im_av(n) and Im_av(n+1) on the vertical axis are Figure 7 The average value of the current measured during the period Tb(n) and Tb(n+1) relative to the period T2(n) and T2(n+1). Fig.11 Similarly, even if the average current values ​​Im_av(n) and Im_av(n+1) are Figure 7 The current measured during the period Tb(n) and Tb(n+1) is also equal to the average value of the current measured during the period Tb(n) and Tb(n+1). Fig.17 The same simulation results. In addition, Fig.11 Similarly, even if the horizontal axis is the measurement period ratio Tb(n+1) / Tb(n), the same Fig.17 The same simulation results.

[0166] exist Fig.17 The simulation results also show that Fig.11 Similarly, there are ranges where the relationship between the cycle ratio and the average current ratio satisfies linearity and ranges where it does not satisfy linearity. In the simulation results, in the range where the cycle ratio is less than 1.1, the relationship between the cycle ratio and the average current ratio does not satisfy linearity, and in the range where the cycle ratio is greater than 1.1, the relationship between the cycle ratio and the average current ratio satisfies linearity. Therefore, in Modification Example 2, as in the above-mentioned embodiment, it is possible to determine whether the current Im is saturated during the period Tb(n) based on whether the relationship between the cycle ratio and the average current ratio satisfies linearity, that is, whether it satisfies the relationship of the above-mentioned formula (1).

[0167] Therefore, in the second modification, it is also possible to Fig.12The measurement result of the current Im when the current Im during discharge is saturated within the period Tb(b) is efficiently acquired by the processing, and the measurement result is output to the signal processing unit 300.

[0168] In this case, Fig.12 Step S12 is changed to a process of measuring the current value during the period Tb(n). Fig.12 In step S13, it is possible to Fig.13 (a) or Fig.13 (b) to appropriately determine whether the current Im during discharge is saturated within the period Tb(b). In this case, Fig.14 The determination methods shown in (a) and (b) are used instead Fig.13 The determination method of (a) and (b).

[0169] In Modification 2, the capacitance of each element portion can also be calculated according to the above formula (2). Fig.13 In the case of the process (a) of step S103, the average current value Im_av(n) (average current value during discharge) when step S103 is "yes" is multiplied by the period T2(n) to obtain the charge amount Qm of equation (2). Fig.13 In the case of the process (b), the charge amount Qm in the formula (2) is directly used as the sum current value Im_sum(n) (the integrated value of the current Im during discharge) when the answer to step S112 is "Yes".

[0170] As described above, in Modification Example 2, the period Tb(n) (measurement period) for measuring the current Im (electricity) can be appropriately set when the period until the current Im (electricity) to be measured is saturated may vary. Therefore, a high-precision measurement result can be obtained efficiently, and the electrostatic capacitance of each component part can be appropriately detected.

[0171] <Change Example 3>

[0172] In the above embodiment, the electric quantity measured by the measuring device 200 is current, but the electric quantity measured by the measuring device 200 may be electric quantity other than current. In Modification 3, the electric quantity measured by the measuring device 200 is set to voltage.

[0173] Fig.18 1 is a diagram showing a configuration of a measuring device 200 according to Modification 3.

[0174] like Fig.18As shown in FIG. 1 , in the third modification, the measuring unit 204 is arranged on the supply line L0. The measuring unit 204 includes a resistor 204a inserted into the supply line L0 and a voltmeter 204b for measuring the voltage across the resistor 204a. The measuring unit 204 may also be arranged at other positions of the supply lines L0 and L1. The control unit 201 Figure 7 The voltage value measured by the voltmeter 204b is obtained during the period Ta(n).

[0175] Fig.19 (a) to (d) are graphs showing the relationship between the voltage Vm measured by the measuring unit 203 and the measurement period.

[0176] When the period Ta(n) (measurement period) starts and the switch element 202a is in the on state, a voltage is applied to the element portion to be measured. At this time, the voltage Vm measured by the measuring unit 203 drops from the power supply potential Vdd by a predetermined potential as the element portion is charged by the voltage application. Thereafter, as the element portion to be measured is charged, the voltage Vm gradually approaches the power supply potential Vdd. Along with this, the voltage drop ΔV of the voltage Vm gradually decreases.

[0177] Here, the period from when the voltage drop ΔV starts to when the voltage Vm converges to the power supply potential Vdd varies depending on the size of the electrostatic capacitance of the element portion to be measured. Fig.19 As shown in (a) and (b) of FIG. 1 , when the load applied to the component part to be measured is small and the electrostatic capacitance of the component part is small, the period until the voltage Vm converges to the power supply potential Vdd is short. On the other hand, Fig.19 As shown in (c) and (d), when the load applied to the element portion to be measured is large and the electrostatic capacitance of the element portion is large, the period until the voltage Vm converges to the power supply potential Vdd is long.

[0178] exist Fig.19 In the cases of (a) and (b), the period during which the voltage drop ΔV occurs is shorter than the periods Ta(n) and Ta(n+1). Therefore, in these cases, the voltage drop ΔV can be measured by the voltmeter 204b for all the periods during which the voltage drop ΔV occurs. Therefore, in these cases, the sum of the voltage drops ΔV (the sum voltage drop ΔV_sum(n)) and the average value of the voltage drops ΔV (the average voltage drop ΔV_av(n)) can be obtained for all the periods during which the voltage drop ΔV occurs.

[0179] The total voltage drop ΔV_sum(n) and the average voltage drop ΔV_av(n) can be calculated by the following equations.

[0180] [Number 1]

[0181] ΔV_sum(n)=∫0Ta(n) ΔVdt…(3)

[0182]

[0183] In equation (4), the average voltage drop ΔV_av(n) is calculated by dividing the total voltage drop ΔV_sum(n) by the period T1(n), but the average voltage drop ΔV_av(n) may be calculated by dividing the total voltage drop ΔV_sum(n) by the period Ta(n).

[0184] exist Fig.19 In the cases of (a) and (b), since the period during which the voltage drop ΔV occurs is shorter than the periods Ta(n) and Ta(n+1), the following relational expression is satisfied.

[0185] ΔV_av(n) / ΔV_av(n+1)=Ta(n+1) / Ta(n)…(5)

[0186] ΔV_sum(n+1) / ΔV_sum(n)=1…(6)

[0187] exist Fig.19 In the cases (c) and (d), the period during which the voltage drop ΔV occurs is longer than the periods Ta(n) and Ta(n+1). Therefore, in these cases, the voltage drop ΔV cannot be measured by the voltmeter 204b for all the periods during which the voltage drop ΔV occurs. Therefore, in these cases, the above equations (3) and (4) are not satisfied.

[0188] In this way, whether or not the equations (3) and (4) are satisfied is determined by whether or not the period during which the voltage drop ΔV is generated is shorter than the periods Ta(n) and Ta(n+1). Therefore, whether or not the period during which the voltage drop ΔV is generated is shorter than the periods Ta(n) and Ta(n+1), that is, whether or not the voltage Vm is saturated and converges to the power supply potential Vdd within the range of the periods Ta(n) and Ta(n+1), can be determined by whether or not the equations (3) and (4) are satisfied.

[0189] The relationship between the rate of change of the voltage drop when the variable n changes ΔV_av(n) / ΔV_av(n+1) and the rate of change during the measurement period Ta(n+1) / Ta(n) is as follows Fig.11 In the range of variable n where the period during which the voltage drop ΔV occurs is shorter than the periods Ta(n) and Ta(n+1), the relationship between the change rate ΔV_av(n) / ΔV_av(n+1) and the change rate Ta(n+1) / Ta(n) satisfies linearity.

[0190] Fig. 20 1 is a flowchart showing a process of acquiring a measurement result of a voltage Vm for a device unit to be measured.

[0191] Fig. 20 The processing is basically the same as that of Fig.12 The same treatment is applied.

[0192] The component part to be measured is Figure 6 In the case of the element unit A11, the first switching unit 120 and the second switching unit 130 are set to Figure 6 In this state, the discharge of all the elements of the load sensor 1 is completed. Then, the control unit 201 of the measuring device 200 starts Figure 7 The gate signals G1 and G2 are output to execute Fig. 20 processing.

[0193] The control unit 201 sets 1 to the variable n (S21), and obtains the measured value of the voltage Vm in the period Ta(n) from the voltmeter 204b (S22). When the measurement of the voltage Vm in the period Ta(n) is completed, the control unit 201 determines whether the voltage Vm is saturated (whether the voltage converges to the power supply potential Vdd) in the period Ta(n) based on the obtained measured value of the voltage Vm (S23). If the determination in step S23 is "No", the control unit 201 adds 1 to the variable n (S25), and returns the process to step S22. Thus, the control unit 201 obtains the measured value of the voltage Vm in the next period Ta(n) (S22), and determines whether the voltage Vm is saturated in the period Ta(n) based on the obtained measured value (S23).

[0194] The control unit 201 performs the same process while increasing the variable n until the determination of step S23 is "yes". If the determination of step S23 is "yes", the control unit 201 outputs the measurement result of the voltage Vm measured during the period Ta(n) to the signal processing unit 300, and ends the output of the gate signals G1 and G2 (S24). Thus, the control unit 201 ends Fig. 20 processing.

[0195] Fig.21 (a) shows Fig. 20 Flowchart of the processing in step S23.

[0196] The control unit 201 calculates the average voltage drop ΔV_av(n) of the voltage Vm based on the voltage Vm acquired in the period Ta(n) (S201). The control unit 201 refers to the change rate V_av(n-1) / ΔV_av(n) between the average voltage drop ΔV_av(n) and the average voltage drop ΔV_av(n-1) calculated for the previous period Ta(n-1), and the change rate Ta(n) / Ta(n-1) between the period Ta(n) and the previous period Ta(n-1) (S202), to determine whether the relationship between the two change rates substantially satisfies linearity (S203).

[0197] The determination of step S203 is similar to the above formula (5) based on whether the change rate V_av(n-1) / ΔV_av(n) and the change rate Ta(n) / Ta(n-1) are substantially equal, for example, whether the difference between the two change rates is within a few %. In addition, when the two change rates are substantially equal during the period when the variable n is increased several times (for example, five times), the determination of step S203 can also be set to "yes". In this way, it can be more accurately determined that the voltage Vm is saturated during the period Ta(n).

[0198] If the determination in step S203 is "yes", the control unit 201 determines that the voltage is saturated in the period Ta(n) (S204), and Fig. 20 On the other hand, if the determination of step S203 is "No", the control unit 201 skips step S204 and sets Fig. 20 The determination of step S23 is set to "No". Thus, the control unit 201 ends Fig.21 (a) processing.

[0199] exist Fig. 20 In step S23, Fig.21 In the case of the processing of (a), the control unit 201 may output the value obtained by multiplying the average voltage drop ΔV_av(n) by the period T1(n) when the answer to step S203 is "Yes", that is, the total voltage drop ΔV_sum(n) as the measurement result in step S24 to the signal processing unit 300. In this case, the signal processing unit 300 calculates the charge amount Qm(n) accumulated in the element unit A11 by the following formula.

[0200] Qm(n)=ΔV_sum(n) / R…(7)

[0201] Here, R is Fig.18 The signal processing unit 300 applies the charge amount Qm calculated in this way to the above equation (2) to calculate the electrostatic capacitance of the element unit A11.

[0202] exist Fig. 20 In the processing, Fig.12 Similarly to the processing of , the period Ta(n) suitable for the element portion A11 can be efficiently set, and efficient and high-precision measurement results can be obtained.

[0203] also, Fig. 20 The processing of step S23 may also be Fig.21 (b) is processed. In this case, the control unit 201 calculates the total voltage drop ΔV_sum(n) (S211) based on the voltage value obtained during the period Ta(n), and determines whether the calculated total voltage drop ΔV_sum(n) substantially converges to a constant (S212). In step S212, the control unit 201 determines whether the difference between the total voltage drop ΔV_sum(n) calculated this time and the total voltage drop ΔV_sum(n-1) calculated last time is within the error range. Alternatively, in step S212, the control unit 201 determines whether the ratio of the total voltage drop ΔV_sum(n) calculated this time to the total voltage drop ΔV_sum(n-1) calculated last time is within the error range centered on 1.

[0204] In this case, when the difference or ratio is maintained within the error range while the variable n is increased several times (e.g., five times), the determination in step S212 may be set to "yes." This makes it possible to more accurately determine that the voltage Vm is saturated during the period Ta(n).

[0205] If the determination in step S212 is "yes", the control unit 201 determines that the voltage is saturated in the period Ta(n) (S213), and Fig. 20 On the other hand, if the determination of step S212 is "No", the control unit 201 skips step S213 and sets Fig. 20 The determination of step S23 is set to "No". Thus, the control unit 201 ends Fig.21 (a) processing.

[0206] In this case, the control unit 201 may output the total voltage drop ΔV_sum(n) when step S212 is "yes" as the measurement result in step S24 to the signal processing unit 300. The signal processing unit 300 applies the acquired total voltage drop ΔV_sum(n) to equation (7) to calculate Qm(n), and applies the calculated Qm(a) to equation (2) to calculate the electrostatic capacitance C of the element unit A11.

[0207] According to the above processing, when the electrostatic capacitance of the component part A11 as the measurement object is obtained, the signal processing unit 300 sequentially switches the component part A11 as the measurement object and calculates the electrostatic capacitance of each component part in the same manner as in the above embodiment. In this way, when the electrostatic capacitance of all the component parts is obtained, the control unit 201 ends the detection processing of the electrostatic capacitance of the load sensor 1 this time.

[0208] According to Modification 3, similarly to Embodiment 1, when the period until the voltage Vm (electricity) to be measured is saturated may vary, the period Ta(n) (measurement period) for measuring the voltage Vm (electricity) can be appropriately set. Therefore, a high-precision measurement result can be efficiently obtained, and the electrostatic capacitance of each element portion can be appropriately detected.

[0209] In addition, in Modification Example 3, Fig.14 Similarly to (a) and (b), it is also possible to determine whether the voltage Vm is saturated based on the relationship between the voltage Vm and the threshold Th2. In this case, the threshold Th2 is set to be slightly lower than the power supply potential Vdd. The control unit 201 determines whether the voltage Vm is saturated in the period Ta(n) based on whether the voltage value Vm_E(n) of the voltage Vm measured at the end timing of the period Ta(n) is greater than the threshold Th2.

[0210] In the third modification, the voltage Vm during discharge can also be detected in the same manner as in the second modification. In this case, the measuring unit 204 is disposed in the path between the switching element 202b and the ground line L3. Figure 7 The voltage of the resistor 204a arranged in the path is measured during the period Tb(n). In this case, it is also possible to Fig. 20 and Fig.21 The measurement result of the voltage Vm during discharge is obtained by performing the same processing as in (a) and (b).

[0211] <Other Changes>

[0212] In the above embodiment, the period Ta(n) is set so that the period Ta(n) as the measurement period becomes longer as the variable (n) increases, but the method of setting the period Ta(n) is not limited to this. For example, for the first element part A11, an appropriate period Ta(n) may be set by the same process as above, and for the next element part A12, the period Ta(n) may be set by the same process as above. Fig.12The length of the period Ta(n) is varied in the length direction with the appropriate period Ta(n) as the center when the judgment of step S13 is "yes", while searching for the appropriate period Ta(n). For the subsequent element parts, the length of the period Ta(n) can be varied in the length direction with the appropriate period Ta(n) for the previous element part as the center, while searching for the appropriate period Ta(n). The same changes can also be applied to the modification examples 2 and 3.

[0213] In addition, the number (number of types) of measurement periods used for measuring the current amount may be set to a number that can efficiently determine that the current amount is saturated.

[0214] In addition, in the above-mentioned embodiment, the charge amount Qm is calculated by multiplying the average current value Im_av(n) by the period T1(n), but the method of obtaining the charge amount Qm is not limited to this. For example, when the average current value Im_av(n) is calculated for the period Ta(n), the charge amount Qm may be calculated by multiplying the average current value Im_av(n) by the period Ta(n). In addition, instead of multiplying by the period T1(n), the charge amount Qm may be calculated by dividing the average current value Im_av(n) by the frequency F1(n) corresponding to the period T1(n). Alternatively, the charge amount Qm may be obtained by accumulating the current Im during the period Ta(n).

[0215] In the above embodiment, the first switch section 120 and the second switch section 130 are formed of the multiplexers 121 , 122 , and 131 . However, the first switch section 120 and the second switch section 130 may be formed of a switching circuit other than a multiplexer.

[0216] In the above embodiment, the multiplexer 122 is disposed before the three multiplexers 112 in the first switching unit 120 . However, the multiplexer 122 may be omitted and the supply line L1 may be directly connected to one input terminal of the three multiplexers 112 .

[0217] In addition, in the above embodiment, nine element units are arranged in a matrix to form the load sensor 1, but the structure of the load sensor 1 is not limited to this. For example, the load sensor 1 may be formed by arranging a plurality of element units in a row, or the load sensor 1 may have only one element unit. In this case, the processing of the above embodiment and Modifications 1 to 3 may be applied to each element unit.

[0218] In the above embodiment, the switch unit 202 has two switch elements 202a and 202b. However, the switch unit 202 may have any other structure as long as it can selectively connect the supply line L1 to the supply line L0 and the ground line L3. For example, the same multiplexer as the multiplexer 121 may be used as the switch unit 202. In this case, the control unit 201 only needs to control the multiplexer to alternately generate Figure 7 The charging period Ta(n) and the discharging period Tb(n) are shown, and the lengths of the period Ta(n) and the period Tn(n) may be lengthened as the variable n increases.

[0219] In the above embodiment, the conductor wire 13 is formed of a copper wire with a coating, but the present invention is not limited thereto and may be formed of a linear conductive member made of a material other than copper and a dielectric coating the conductive member.

[0220] In addition, in the above-mentioned embodiment, the conductive elastic body 12 is provided only on the surface on the positive side of the Z axis of the base member 11, but the conductive elastic body may also be provided on the surface on the negative side of the Z axis of the base member 15. In this case, the conductive elastic body on the side of the base member 15 is configured in the same manner as the conductive elastic body 12 on the side of the base member 11, and is arranged to overlap with the conductive elastic body 12 in a manner of sandwiching the conductor line 13 when viewed from above. Moreover, the cable led out from the conductive elastic body on the side of the base member 15 is connected to the cable 12a led out from the conductive elastic body 12 facing each other in the Z axis direction. In this way, when the conductive elastic body is provided up and down with respect to the conductor line 13, the change in electrostatic capacitance in the element portion is approximately twice that corresponding to the upper and lower conductive elastic bodies, so that the detection sensitivity of the load applied to the element portion can be improved.

[0221] In addition, in the above embodiment, the dielectric 13b is formed for the conductive member 13a so as to cover the outer periphery of the conductive member 13a, but the dielectric 13b may be formed on the upper surface of the conductive elastic body 12 instead. In this case, the conductive member 13a sinks in a manner surrounded by the conductive elastic body 12 and the dielectric 13b according to the application of the load, and the contact area between the conductive member 13a and the conductive elastic body 12 changes. Thereby, the load applied to the element portion can be detected in the same manner as in the above embodiment.

[0222] In addition, in the above embodiment, the element portion is formed by the conductive elastic body 12 and the conductor wire 13 intersecting each other, but the structure of the element portion is not limited to this. For example, the element portion may be formed by a structure in which a dielectric is sandwiched between a hemispherical conductive elastic body and a flat electrode. In this case, the dielectric may be formed on the surface of the electrode facing the conductive elastic body, or on the surface of the hemispherical conductive elastic body.

[0223] Furthermore, the measuring device according to the present invention can be suitably used not only for load sensors but also for other circuits in which the electric charge of the detection target changes and becomes saturated, such as electrostatic touch panels, capacitive elements formed in semiconductor devices, electrolytic capacitors, and ceramic capacitors.

[0224] In addition, the embodiments of the present invention can be variously modified as appropriate within the scope of the technical concept shown in the claims.

[0225] (Note)

[0226] According to the description of the above embodiments, the following technology is disclosed.

[0227] (Technology 1)

[0228] A measuring device, characterized by comprising:

[0229] A switching unit for switching between applying a voltage to the circuit and not applying a voltage;

[0230] a measuring unit configured to measure the amount of electricity at a predetermined location in the circuit; and

[0231] a control unit that controls the switching unit and the measuring unit to measure the amount of electricity that changes and becomes saturated at the predetermined portion,

[0232] The control unit performs the following processing:

[0233] Set multiple different measurement periods;

[0234] Starting to apply the voltage in synchronization with the start of each of the measurement periods;

[0235] determining whether the amount of electricity measured by the measuring unit in each of the measurement periods is saturated; and

[0236] The measurement result of the electric quantity is acquired according to the measurement period in which it is determined that the electric quantity is saturated.

[0237] According to this technology, the measurement result of the electric quantity is obtained according to the measurement period in which the electric quantity as the measurement object is determined to be saturated among a plurality of different measurement periods. Therefore, even if the period until the electric quantity as the measurement object is saturated may vary, the measurement period of the electric quantity can be appropriately set, and a high-precision measurement result can be efficiently obtained.

[0238] (Technique 2)

[0239] The measuring device according to technique 1 is characterized in that

[0240] The control unit performs the following processing:

[0241] causing the lengths of the plurality of measurement periods to change sequentially along one direction;

[0242] calculating an average value of the electrical quantity for each of the measurement periods; and

[0243] Whether the power is saturated is determined according to whether the rate of change during the measurement period and the rate of change of the average value substantially satisfy linearity.

[0244] According to this technology, it is possible to accurately determine whether the electric quantity is saturated during the measurement period.

[0245] (Technique 3)

[0246] The measuring device according to technique 1 is characterized in that

[0247] The control unit performs the following processing:

[0248] sequentially changing the lengths of the plurality of measurement periods in one direction; and

[0249] Whether the electric quantity is saturated is determined according to whether the sum of the electric quantities acquired in each of the measurement periods substantially converges to a constant value.

[0250] According to this technique, similarly to the technique 2, it is possible to appropriately determine whether the electric quantity is saturated within the measurement period.

[0251] (Technique 4)

[0252] The measuring device according to technology 2 or 3 is characterized in that

[0253] The control unit sequentially increases the lengths of the plurality of measurement periods.

[0254] According to this technique, the measurement period can be gradually brought close to the length of the electric charge saturation, so that an appropriate measurement period can be smoothly set.

[0255] (Technique 5)

[0256] The measuring device according to any one of techniques 1 to 4 is characterized in that:

[0257] The electrical quantity is electric current.

[0258] According to this technology, through the above-mentioned processing, it is possible to appropriately set the measurement period according to the change in the current.

[0259] (Technique 6)

[0260] The measuring device according to any one of techniques 1 to 4 is characterized in that:

[0261] The electrical quantity is a voltage.

[0262] According to this technology, through the above-mentioned processing, it is possible to appropriately set the measurement period according to the change in the current.

[0263] (Technique 7)

[0264] A load detection system, characterized by comprising:

[0265] A load sensor including an element portion whose electrostatic capacitance changes according to a load;

[0266] a voltage applying section including the measuring device according to any one of techniques 1 to 6, for applying a voltage to the element section; and

[0267] a signal processing unit that acquires the electrostatic capacitance of the element unit from the measurement result of the measuring device,

[0268] Wherein, the measuring device performs the following processing:

[0269] applying the voltage to the element portion through the switching portion;

[0270] measuring the electric quantity at a predetermined position of the voltage applying part by the measuring part; and

[0271] The measurement result of the electric quantity acquired by the control unit is output to the signal processing unit.

[0272] According to this technique, since the measuring device described in any one of techniques 1 to 6 is used, even if the electrostatic capacitance of the component part changes according to the load, the measurement period corresponding to the electrostatic capacitance can be set. Therefore, the electric quantity corresponding to the electrostatic capacitance can be measured efficiently and accurately, and the load of the component part can be detected with high accuracy.

[0273] (Technology 8)

[0274] The load detection system according to technology 7 is characterized in that:

[0275] The load sensor includes a plurality of the element parts.

[0276] The voltage applying section is configured to be able to switch the element section to which the voltage is applied,

[0277] The signal processing unit controls the potential applying unit to apply the voltage to each of the element units, acquires the measurement result from the measuring unit for each of the element units, and acquires the electrostatic capacitance of each of the element units from the acquired measurement result.

[0278] According to this technology, since a plurality of element parts are arranged, the load detection range can be expanded. In addition, since the above-mentioned processing is performed on each element part, the electrostatic capacitance given to each element part can be detected with high accuracy, and the load of each element part can be detected efficiently.

[0279] (Technique 9)

[0280] The load detection system according to technology 8 is characterized in that:

[0281] The plurality of element portions are arranged in a matrix in a plurality of rows and columns.

[0282] One electrodes of the element portions of the same row are connected to each other,

[0283] The other electrodes of the element parts of the same column are connected to each other,

[0284] The voltage applying section includes a switching element that switches between the row and the column to which the voltage is applied.

[0285] According to this technology, since a plurality of element parts are arranged in a matrix, the distribution of loads extending in a square range can be detected by these element parts. In addition, by switching the row and column to which the potential is to be applied using a switching element, a predetermined potential can be applied to the two electrodes of the element part located at the intersection of the switched row and column, respectively, and the electrostatic capacitance of the element part can be efficiently detected by the above control.

[0286] Description of Reference Numerals

[0287] 1: load sensor; 3: load detection system; 100: voltage application unit; 121, 122, 131: multiplexer (switching element); 200: measuring device; 201: control unit; 202: switching unit; 203, 204: measuring unit; 300: signal processing unit; A11~A16: element unit; Ta(n), Tb(n): period (measurement period).

Claims

1. A measuring device, characterized in that: have: A switching unit for switching between applying a voltage to the circuit and not applying a voltage; a measuring unit configured to measure the amount of electricity at a predetermined location in the circuit; and a control unit that controls the switching unit and the measuring unit to measure the amount of electricity that changes and becomes saturated at the predetermined portion, The control unit performs the following processing: Set multiple different measurement periods; Starting to apply the voltage in synchronization with the start of each of the measurement periods; determining whether the amount of electricity measured by the measuring unit in each of the measurement periods is saturated; and The measurement result of the electric quantity is acquired according to the measurement period in which it is determined that the electric quantity is saturated.

2. The measuring device according to claim 1, characterized in that The control unit performs the following processing: causing the lengths of the plurality of measurement periods to change sequentially along one direction; Calculating an average value of the electrical quantity for each of the measurement periods; as well as Whether the power is saturated is determined according to whether the rate of change during the measurement period and the rate of change of the average value substantially satisfy linearity.

3. The measuring device according to claim 1, characterized in that The control unit performs the following processing: sequentially changing the lengths of the plurality of measurement periods in one direction; and Whether the electric quantity is saturated is determined according to whether the sum of the electric quantities acquired in each of the measurement periods substantially converges to a constant value.

4. The measuring device according to claim 2, characterized in that The control unit sequentially increases the lengths of the plurality of measurement periods.

5. The measuring device according to claim 1, characterized in that The electrical quantity is electric current.

6. The measuring device according to claim 1, characterized in that The electrical quantity is a voltage.

7. A load detection system, characterized in that: have: A load sensor including an element portion whose electrostatic capacitance changes according to a load; a voltage applying section, comprising the measuring device according to any one of claims 1 to 6, for applying a voltage to the element section; and a signal processing unit that acquires the electrostatic capacitance of the element unit from the measurement result of the measuring device, Wherein, the measuring device performs the following processing: applying the voltage to the element portion through the switching portion; measuring the electric quantity at a predetermined position of the voltage applying part by the measuring part; and The measurement result of the electric quantity acquired by the control unit is output to the signal processing unit.

8. The load detection system according to claim 7, characterized in that: The load sensor includes a plurality of the element parts. The voltage applying section is configured to be able to switch the element section to which the voltage is applied, The signal processing unit controls the potential applying unit to apply the voltage to each of the element units, acquires the measurement result from the measuring device for each of the element units, and acquires the electrostatic capacitance of each of the element units from the acquired measurement result.

9. The load detection system according to claim 8, characterized in that: The plurality of element portions are arranged in a matrix in a plurality of rows and columns. One electrodes of the element portions of the same row are connected to each other, The other electrodes of the element parts of the same column are connected to each other, The voltage applying section includes a switching element that switches between the row and the column to which the voltage is applied.

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