Physical quantity measurement system and physical quantity detection device

Abstract

[Problem] To remotely measure, using a simple configuration, a physical quantity such as the weight (load) of an object placed on a sensor or the pressure applied to the sensor. [Solution] In the present invention, a placement part 111 is provided on one surface of an upper plate 112 and a movable electrode 113 is provided on the opposite surface. An elastic member is sandwiched between the upper plate 112 and a lower plate 115. First and second fixed electrodes 114A and 114B are provided to the lower plate 115 in positions opposite the movable electrode 113. The second fixed electrode 114B and the movable electrode 113 are conductively connected to form a variable capacitor 110. Capacitance is detected by a capacitive sensor tag 120 and wirelessly transmitted to an information processing device 30. The information processing device 30 measures the weight of an object to be measured MO placed on the placement part 111 on the basis of the capacitance and measurement reference data.

Description

Physical quantity measurement system and physical quantity detection device

[0001] This invention relates to a physical quantity measurement system for detecting load or pressure, etc. In particular, this invention relates to a physical quantity measurement system for detecting load or pressure wirelessly, etc.

[0002] Conventionally, various devices have been proposed that measure the weight (load) of an object placed on the movable electrode side and the pressure applied to the movable electrode side, by arranging a fixed electrode and a movable electrode opposite each other and providing an elastic body such as a leaf spring between the fixed electrode and the movable electrode (for example, Patent Documents 1 and 2). These types of devices are configured to detect the weight of an object placed on the movable electrode side and the pressure applied to the movable electrode side based on the change in capacitance that occurs due to the change in the distance between the electrodes, which changes in response to the weight (load) of an object placed on the movable electrode side and the pressure applied to the movable electrode side.

[0003] Recently, sensors have also been proposed that combine multiple RFID (Radio Frequency Identification) devices, each equipped with switches that have different load and pressure values ​​as on / off control thresholds, and which pre-store data indicating these threshold load and pressure values ​​(for example, Patent Document 3). This sensor has the function of wirelessly transmitting data corresponding to the threshold from an ON RFID device, and displaying the range of load and pressure applied to the sensor at a location away from the sensor (for example, Patent Document 3).

[0004] Furthermore, RFID tags equipped with ICs that have a capacitive sensor function capable of measuring capacitance values ​​with very low power consumption have recently been proposed (for example, Patent Document 4). Because RFID tags equipped with this capacitive sensor can detect capacitance with very low power consumption, it is possible to accurately detect capacitance values ​​even when using passive drive and communication modes.

[0005] Japanese Patent Publication No. Hei 7-270219, Japanese Patent Publication No. Sho 63-2203530, Japanese Patent Publication No. 2005-158018, Japanese Patent Publication No. 2020-134354

[0006] However, the inventions described in Patent Documents 1 and 2 above are configured to display the load or pressure detected by a sensor composed of electrodes on a display device electrically connected to the sensor. Therefore, it is difficult to confirm physical quantities such as load or pressure at a location far from where the sensor is installed. Furthermore, the invention described in Patent Document 3 allows for the remote display and confirmation of the load or pressure applied to the sensor. This invention is configured to display the range of load or pressure applied to the sensor by combining multiple RFIDs having switches with different on / off thresholds. Therefore, not only does the sensor become more complex and larger, but it is also difficult to accurately measure the load or pressure.

[0007] The present invention has been made in view of the circumstances described above, and its purpose is to provide a physical quantity measurement system that can detect physical quantities such as the weight (load) of an object placed on a sensor and the pressure applied to the sensor with a simple configuration, and measure them remotely.

[0008] (1) In order to solve the above-mentioned problems, the physical quantity measurement system according to the present invention comprises two members connected opposite to each other by an elastic member, (1) a first member which is installed to be movable when a load or pressure is applied and which has a movable electrode disposed thereon, and (2) a second member which has a fixed electrode disposed at a position opposite to the movable electrode and which does not move and is fixed even when a load or pressure is applied to the first member, and a variable capacitor whose capacitance value changes due to the change in the distance between the movable electrode and the fixed electrode when the first member moves as the elastic member elastically deforms in accordance with the applied load or pressure, and a variable capacitor which is electrically connected to the variable capacitor, and the variable capacitor The device includes: (1) a capacitance sensor that detects the capacitance value and transmits corresponding detection data wirelessly; (2) reference data that defines the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and obtained by a predetermined calculation based on the result of pre-measurement of the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor; and (3) a physical quantity measuring device that measures the value of the load or pressure applied to the first member based on the detection data wirelessly transmitted by the capacitance sensor and performs processing based on the measurement result.

[0009] In this configuration, in the physical quantity measurement system of the present invention, when a load or pressure is applied to the first member (corresponding to the upper plate 112 described later) on which the movable electrode is located, the elastic member connecting the first member and the second member (corresponding to the lower plate 115 described later) (for example, the coil springs CS1 to 4 and leaf springs LS1 to 4 described later) deforms, and the first member moves toward the second member. On the other hand, the second member does not move, and the distance between the electrodes between the movable electrode and the fixed electrode changes according to the load or pressure applied to the first member. As a result, in the physical quantity measurement system of the present invention, the capacitance value of the variable capacitor constructed by the movable electrode and the fixed electrode changes. Since the capacitance value of the capacitor depends on the distance between the electrodes, as shown in (Equation 1) described later, when the distance between the electrodes changes according to the load or pressure applied to the first member, the capacitance value of the variable capacitor changes accordingly. The capacitance sensor detects this capacitance value of the variable capacitor and transmits detection data indicating the detection result wirelessly to the physical quantity measurement device. On the other hand, the physical quantity measuring device measures the value of the load or pressure applied to the first member and performs processing based on the following: (a) reference data obtained by performing a predetermined calculation based on the results of a prior measurement of the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, which defines the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, and (b) detection data wirelessly transmitted by the capacitance sensor.

[0010] As a result, the physical quantity measurement system of the present invention allows for the remote measurement of physical quantities such as the weight of an object placed on the first member of a variable capacitor (i.e., the load applied to the first member) or the pressure applied to the first member of the variable capacitor by a physical quantity measurement device. The physical quantity measurement device can then perform various processes using the measurement results. Furthermore, the variable capacitor, which functions as a load or pressure sensor, can be constructed very simply and at low cost by connecting a first member on which a movable electrode is provided and a second member on which a fixed electrode is provided, using an elastic member so that the movable electrode and the fixed electrode face each other. Moreover, the capacitance sensor can be configured, for example, as an RFID that can be manufactured at low cost, or as a capacitance tester with wireless communication capabilities. This allows for the detection of the capacitance value of the variable capacitor obtained by converting the load or pressure value applied to the first member of the variable capacitor (sensor) at low cost, and the detection result can be transmitted wirelessly to the physical quantity measurement device.

[0011] Here, we consider a case where (a) a first member provided with a movable electrode and (b) a second member provided with a fixed electrode are connected by an elastic member, and a variable capacitor is constructed using the movable and fixed electrodes. In this case, the change characteristics of the capacitance value of the variable capacitor when a load or pressure is applied (hereinafter also referred to as the "initial characteristics of the variable capacitor") will vary from one variable capacitor to another due to the influence of individual differences in the elastic members constituting the variable capacitor. For example, even if coil springs or leaf springs with the same spring constant and initial length are used as elastic members, it is extremely difficult to manufacture coil springs or leaf springs with exactly the same characteristics due to manufacturing tolerances of the coil springs or leaf springs. Furthermore, it is difficult to manufacture exactly the same movable and fixed electrodes on the corresponding members due to manufacturing tolerances. For this reason, even when variable capacitors are manufactured with the same configuration, the initial characteristics of the variable capacitor will vary from one variable capacitor to another. Therefore, even when using variable capacitors manufactured with the same configuration according to specifications, in order to appropriately measure the load or pressure applied to the first component using a physical quantity measuring device, it is necessary to use reference data that has been appropriately adjusted according to the initial characteristics of each individual variable capacitor actually used. Furthermore, even with the same individual variable capacitor, if a condition occurs that changes the characteristics of the variable capacitor before it is installed in the facility where it will be used (for example, a warehouse, etc.) (for example, a condition corresponding to "characteristic change conditions d and e" described later), the characteristics of the variable capacitor will change from the initial characteristics at the time of manufacture. Therefore, in order to appropriately measure the load or pressure applied to the first component after newly installing a variable capacitor in a facility, it is necessary to use reference data that has been adjusted to match the characteristics of the variable capacitor at the time of installation, including both (i) the initial characteristics of the variable capacitor and (ii) the characteristic changes that occurred before on-site installation.

[0012] In this regard, the present invention provides a physical quantity measuring device that measures the value of the load or pressure applied to the first member based on (a) data defining the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, which includes the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and reference data obtained by performing a predetermined calculation on the measurement results of the load or pressure applied to the first member and the capacitance value of the variable capacitor, and (b) detection data. Therefore, with this configuration, even if the initial characteristics of the variable capacitor are different or if the characteristics change before the on-site installation of the variable capacitor, reference data that reflects the difference in initial characteristics or the change in characteristics that occurred before installation can be generated by a predetermined calculation. The physical quantity measuring device can then measure the value of the load or pressure applied to the first member using the generated reference data.

[0013] Accordingly, the physical quantity measurement system of the present invention can obtain, at low cost and with a very simple configuration, the value of the load or pressure applied to the first member by a physical quantity measurement device installed at a location away from the installation location of a variable capacitor that functions as a load or pressure sensor, by converting it into the capacitance value of the variable capacitor and obtaining it from a capacitance sensor. The physical quantity measurement device can appropriately measure the value of the load or pressure applied to the first member based on (a) reference data adjusted to match the characteristics of the variable capacitor, including the initial characteristics of the variable capacitor actually used and characteristic changes that occurred before installation, and (b) detection data obtained from the capacitance sensor, and can perform processing based on the measurement result. The specific processing content to be performed by the physical quantity measurement device is arbitrary. For example, (1) the physical quantity measurement device can display the measurement result, or notify the user of the measurement result using at least one of voice and / or images. Also, (2) the physical quantity measurement device can perform processing for inventory management of goods. Furthermore, (3) the physical quantity measurement device can perform processing to monitor the change in pressure while measuring the pressure value applied to the first member of the variable capacitor, which is installed in real space as a pressure sensor. This point, as well as the specific calculations used by physical quantity measuring devices to generate reference data, will be described in detail later.

[0014] (2) In addition, in the above configuration, the physical quantity measuring device may employ a configuration in which it measures the value of the load or pressure applied to the first member based on (a) at least two measurement results obtained by actually measuring the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, which include the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, by performing a calculation based on a first mathematical formula that includes unknown first and second parameters as a predetermined calculation and defines the relationship between the capacitance value of the variable capacitor and the load or pressure applied to the first member, thereby determining the values ​​of the first and second parameters suitable for the characteristics of the variable capacitor and generating the reference data, and (b) the detection data.

[0015] With this configuration, in the physical quantity measurement system of the present invention, as described later, a physical quantity measurement device that generates reference data or calibrated reference data acquires at least two measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and the measurement result of the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, which has been measured in advance. Then, the physical quantity measuring device, etc., includes unknown first and second parameters (corresponding to parameters "A and B" described later) in the measurement result and performs calculations based on a first mathematical formula (Equation 11 described later, or a third mathematical formula described later, which can be obtained by modifying Equation 11, etc., described later (specifically corresponding to Equation 15 described later)) that defines the relationship between the capacitance value of the variable capacitor and the load or pressure applied to the first member. As a result, the physical quantity measuring device, etc., determines values ​​for the first and second parameters that are suitable for the characteristics of the variable capacitor at the time of field installation, including the initial characteristics of the variable capacitor. Then, the physical quantity measuring device, etc., can generate reference data suitable for the actual characteristics of the variable capacitor by applying the determined first and second parameters, or generate calibrated reference data. As a result, the physical quantity measuring device can measure the value of the load or pressure applied to the first member based on the generated reference data or calibrated reference data and the detection data.

[0016] Generally, to generate reference data suitable for the initial characteristics of each newly manufactured variable capacitor, it is necessary to actually apply a known load or pressure to the first component using the corresponding individual capacitor, measure the capacitance value of the variable capacitor at that time, and generate reference data based on the measurement results. In this case, the reference data usually needs to be generated by obtaining measurement results from a large number of measurement points (for example, about 10 points) and obtaining an appropriate approximate straight line or approximate curve for these measurement results. Here, as mentioned above, the initial characteristics of a variable capacitor differ from one individual to another, and even for the same individual, they change depending on the condition that occurred before on-site installation. For this reason, as will be described later, when newly manufacturing a variable capacitor and installing a system on-site, it is necessary to perform the measurement work using the actual variable capacitor to be used, for example, using a physical quantity measuring device or an external PC (Personal Computer), and generate and use reference data that reflects the actual characteristics, including the initial characteristics of the variable capacitor being installed.

[0017] Furthermore, even after the system has been installed and put into operation, the characteristics of the variable capacitor will change if conditions such as those listed below (corresponding to "characteristic change conditions a to c" described later) are met. These conditions include: (1) deterioration of the elastic member due to aging; (2) replacement of at least a part of the elastic member due to deterioration due to aging; and (3) application of a load or pressure to the first member that exceeds a predetermined limit value as a measurable load or pressure value. Therefore, when a condition meeting these predetermined conditions occurs, it is necessary to appropriately calibrate the reference data generated at the time of on-site installation to suit the characteristics of the variable capacitor after the characteristic change, and to perform measurement and calibration work to generate calibrated reference data (corresponding to the calibrated measurement reference data described later). Generally, this type of calibration requires numerous measurements (around 10 points) as described above. Therefore, repeating this measurement work each time a condition meeting these predetermined conditions occurs is extremely cumbersome and may impair user convenience. In particular, when implementing a usage scenario in which the load and pressure applied to the first component of multiple variable capacitors are centrally managed by a single physical quantity measuring device, the user will need to repeat the same measurement work for each variable capacitor whenever the above predetermined conditions are met, not only during system construction but also during system operation, making it difficult to ensure convenience.

[0018] On the other hand, in the physical quantity measurement system of the present invention employing the above configuration, the physical quantity measurement device, etc., which generates and constructs reference data, acquires measurement results from at least two points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member. The physical quantity measurement device, etc., then performs calculations based on the first mathematical formula on the measurement results, thereby generating reference data suitable for the actual characteristics of the variable capacitor to be newly installed on site. Furthermore, according to the above configuration, even if a condition occurs that satisfies predetermined conditions for calibrating the reference data, the physical quantity measurement device, etc., can generate calibrated reference data based on the at least two measurement results acquired above, in accordance with the characteristics of the variable capacitor after the occurrence of the condition. As will be described in more detail later, the first and second parameters in the first mathematical formula incorporate (a) elements corresponding to the characteristics of the elastic member constituting the variable capacitor (for example, characteristics such as spring constant, initial length, and natural length) and (b) elements corresponding to the characteristics of the movable electrode and fixed electrode (for example, characteristics such as electrode area). Therefore, by determining first and second parameters suitable for the characteristics of the variable capacitor through calculations based on the first mathematical formula, the physical quantity measuring device can generate reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor. Furthermore, this method allows the physical quantity measuring device to appropriately calibrate the reference data to match the characteristics of the variable capacitor after a state satisfying predetermined conditions has occurred, thereby generating calibrated reference data. The specific method by which the physical quantity measuring device determines the first and second parameters based on the first mathematical formula to suit the current characteristics of the variable capacitor, and the physical meaning of the first and second parameters included in the first mathematical formula, will be described in detail later.

[0019] In particular, the first formula includes only two unknown parameters, the first and second parameters, and defines the relationship between the capacitance value of the variable capacitor and the value of the load or pressure applied to the first member. When there are two unknown parameters, as described later, if there are two measurement results of the capacitance value of the variable capacitor under conditions where a known load or pressure is applied to the first member, the values ​​of the first and second parameters in the first formula can be determined. Therefore, according to this configuration, the capacitance value of the variable capacitor is measured at two points: (state a) when no load or pressure is applied to the first member, and (state b) when a predetermined value of load or pressure (known) is applied. If a physical quantity measuring device performs calculations based on the first formula on these measurement results, the values ​​of the first and second parameters suitable for the characteristics of the variable capacitor can be determined. In other words, according to this configuration, based on the measurement results at two points in the two states, the physical quantity measuring device can generate reference data suitable for the actual characteristics of the variable capacitor at the time of on-site installation, including the initial characteristics of the variable capacitor. Furthermore, according to this configuration, the physical quantity measuring device can appropriately generate calibrated reference data by determining the first and second parameters suitable for the characteristics of the variable capacitor after the occurrence of the condition that satisfies the above predetermined conditions.Therefore, according to this configuration, the physical quantity measuring device can generate appropriate reference data or calibrate the reference data to appropriately generate calibrated measurement reference data, while dramatically simplifying the measurement work during the generation and calibration of the reference data.Note that the number of measurement points used for generating and calibrating the reference data may be, for example, about 10 points as in the conventional method, and calculations based on the first mathematical formula may be performed using these measurement points to determine the first and second parameters and generate and calibrate the reference data.However, in order to reduce the measurement burden, it is desirable to generate reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor, using the measurement results of two points, including a state in which no load or pressure is applied to the first member, or to generate calibrated reference data configured to suit the characteristics of the variable capacitor after the occurrence of the condition that satisfies the above predetermined conditions.

[0020] The specific calculation methods used for generating and calibrating the reference data are arbitrary. For example, (Method a) The physical quantity measuring device acquires at least two measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, as described below. The physical quantity measuring device then performs regression analysis based on the first mathematical formula on the measurement results to determine the values ​​of the first and second parameters that are suitable for the actual characteristics of the variable capacitor at the time of on-site installation, including the initial characteristics of the variable capacitor. The physical quantity measuring device then generates reference data by applying the determined first and second parameters, or generates calibrated reference data based on the values ​​of the first and second parameters that are suitable for the characteristics of the variable capacitor after the above predetermined conditions are met. Alternatively, (Method b) The physical quantity measuring device acquires at least two measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member. Then, the physical quantity measuring device, etc., determines values ​​for the first and second parameters that are suitable for the characteristics of the variable capacitor at the time of on-site installation, or for the characteristics of the variable capacitor after a predetermined condition has occurred, by performing calculations based on a third formula (corresponding to (Formula 15) described later) calculated based on the first formula for the measurement results.The physical quantity measuring device, etc., may then generate reference data by applying the first and second parameters determined in this way, or generate reference data that has been calibrated to be suitable for the characteristics of the variable capacitor after a condition that satisfies the predetermined conditions has occurred.

[0021] (3) In addition, in the configuration described in claim 2, the physical quantity measuring device may, instead of the reference data generated by calculation based on the first formula, use the following configuration: (a) Measurement results of at least three points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, to which an unknown third parameter is added as the first formula as a predetermined calculation, and to which the reference data is generated by determining the values ​​of the first to third parameters in the second formula that are suitable for the characteristics of the variable capacitor; and (b) a configuration in which the value of the load or pressure applied to the first member is measured based on the detection data.

[0022] With this configuration, in the physical quantity measurement system of the present invention, (a) measurement results of at least three points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, are acquired by the physical quantity measurement device, etc., as described later. The physical quantity measurement device, etc. then performs calculations based on the second formula (corresponding to (Formula 16) described later) to determine the values ​​of the first to third parameters, which are suitable for the characteristics of the variable capacitor, including the initial characteristics. With this configuration, the physical quantity measurement device, etc. can generate reference data based on the values ​​of the first to third parameters determined in this way. Furthermore, with this configuration, even if a condition occurs that satisfies predetermined conditions for calibrating the above reference data, the physical quantity measurement device, etc. can perform calculations based on the second formula on the above at least three measurement results to determine the values ​​of the first to third parameters, which are suitable for the characteristics of the variable capacitor after the occurrence of the condition. Furthermore, according to this configuration, the physical quantity measuring device can generate calibrated reference data based on the first to third parameters that have been determined. Furthermore, according to this configuration, the physical quantity measuring device can measure the value of the load or pressure applied to the first member based on (b1) reference data generated by calculation based on the second formula, or (b2) the calibrated reference data and detection data, rather than (a1) reference data generated by calculation based on the first formula, or (a2) reference data calibrated by calculation based on the first formula.

[0023] In particular, the variable capacitor constituting the physical quantity measurement system of the present invention is affected by parasitic capacitance and other factors depending on its configuration. In this case, if reference data suitable for the actual characteristics of the variable capacitor at the time of field installation, including the initial characteristics of the variable capacitor, is generated using the first formula, or if the reference data is calibrated after the occurrence of predetermined conditions to generate calibrated reference data, the fit of the reference data or the calibrated reference data obtained by calibrating it to the measurement results may decrease slightly, as described later. On the other hand, with the configuration using the second formula described above, the effects of parasitic capacitance and other factors can be incorporated into the third parameter, as described later. As a result, with this configuration, the physical quantity measurement device can (a) generate reference data that fits the measurement results very well, and (b) calibrate the reference data with high accuracy to generate calibrated reference data. However, when generating reference data using the second formula, or when calibrating the reference data to generate calibrated reference data, there will be three unknown parameters, the first to the third. Therefore, the number of measurement results required for generating and calibrating the reference data also changes from when it is determined based on the first formula, and at least three measurement results are required instead of at least two. The measurement results used at this time are arbitrary. However, in order to reduce the workload when acquiring measurement results, the capacitance value of the variable capacitor is measured at three points: (state a) when no load or pressure is applied to the first member, and (state b) when two predetermined loads or pressures (known) are applied. The first to third parameters suitable for the characteristics of the variable capacitor at the time of on-site installation or after the conditions have been met are determined by performing calculations based on the second formula on these measurement results. Then, it is desirable that a physical quantity measuring device, etc., applies these first to third parameters to generate reference data, or generates reference data calibrated to suit the characteristics of the variable capacitor after the conditions have been met. By adopting this method, the measurement work involved in generating and calibrating reference data suitable for the actual characteristics of the variable capacitor during on-site installation, including its initial characteristics, can be simplified, dramatically improving user convenience.

[0024] Furthermore, when this configuration is adopted, the specific calculation method used by the physical quantity measuring device, etc., to generate reference data suitable for the actual characteristics of the variable capacitor at the time of on-site installation, including initial characteristics, or to generate calibrated reference data, is arbitrary, just as when the first formula is used. For example, (Method a) The physical quantity measuring device or external PC, etc., is configured to acquire at least three measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, as described later. The physical quantity measuring device, etc., then employs a method in which it determines, as described later, the values ​​of the first to third parameters, suitable for (i) the actual characteristics of the variable capacitor at the time of on-site installation, including initial characteristics of the variable capacitor, or (ii) the characteristics of the variable capacitor after the above predetermined conditions are met, by regression analysis based on the second formula on the measurement results. The physical quantity measuring device, etc., then may generate (i) reference data suitable for the characteristics of the newly installed variable capacitor by applying the determined first to third parameters. Furthermore, (ii) when a condition satisfying the above predetermined conditions occurs, the physical quantity measuring device, etc., may generate reference data calibrated to suit the characteristics of the variable capacitor after the occurrence of said condition. In addition, (method b) as described later, the physical quantity measuring device, etc., acquires at least three measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member. The physical quantity measuring device, etc., then determines, based on the measurement results, the values ​​of the first to third parameters that are suitable for (i) the characteristics of the variable capacitor at the time of on-site installation, including the initial characteristics, or (ii) the characteristics of the variable capacitor after the occurrence of the condition satisfying the above predetermined conditions, based on a predetermined set of mathematical formulas (specifically corresponding to (formula 18) to (formula 20) described later). The physical quantity measuring device, etc., then may apply the first to third parameters determined in this way to generate reference data suitable for the characteristics of the variable capacitor at the time of on-site installation, or to generate reference data calibrated to suit the characteristics of the variable capacitor after the occurrence of the condition satisfying the above predetermined conditions.

[0025] (4) Furthermore, in the configuration described in claim 2, the physical quantity measuring device (A) when the variable capacitor is newly installed, obtains measurement results from at least two points in which the relationship between the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and determines the values ​​of the first and second parameters in the first formula that are suitable for the characteristics including the initial characteristics of the variable capacitor by regression analysis based on the first formula on the measurement results, and generates the reference data suitable for the initial characteristics of the variable capacitor based on the determined values ​​of the first and second parameters, and (a) using the generated reference data, the load or pressure applied to the first member While measuring the force value, (B) if a condition that satisfies predetermined conditions occurs after the installation of the variable capacitor, the relationship between the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured and the measurement results of at least two points are obtained. Based on the measurement results, regression analysis based on the first formula is performed to determine the values ​​of the first and second parameters that are suitable for the characteristics of the variable capacitor after the condition that satisfies the applicable conditions occurs. Based on the determined values ​​of the first and second parameters, the reference data is calibrated to generate calibrated reference data that is suitable for the characteristics of the variable capacitor after the condition that occurs. The load or pressure applied to the first member is then measured using the calibrated reference data instead of the reference data generated at the time of initial installation.

[0026] With this configuration, the physical quantity measurement system of the present invention can generate reference data suitable for (i) the actual characteristics of a variable capacitor newly installed on site, including its initial characteristics (specifically, the initial characteristics of the variable capacitor, and, if conditions corresponding to the characteristic change conditions d and e described later occur before installation, causing the characteristics to change, the characteristics after such characteristic change). Furthermore, the physical quantity measurement system is configured such that (ii) when a condition occurs that satisfies predetermined conditions (corresponding to the "characteristic change conditions a to c" described later) for which the reference data should be calibrated, the physical quantity measurement device or an external PC, etc., acquires at least two measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, as described later. The physical quantity measurement device or external PC, etc., then performs regression analysis (nonlinear regression) based on the first mathematical formula on the acquired measurement results to determine, respectively, values ​​for the first and second parameters suitable for (i) the actual characteristics of the variable capacitor, including its initial characteristics, or (ii) the characteristics of the variable capacitor after the occurrence of the condition that satisfies the predetermined conditions. Then, by applying the values ​​of the first and second parameters, which are suitable for the characteristics of the variable capacitor determined in this way, the physical quantity measuring device can generate appropriate reference data suitable for the characteristics of the corresponding variable capacitor at the time of new installation. Furthermore, by applying the first and second parameters determined by the above method, the physical quantity measuring device can appropriately calibrate the reference data according to the characteristics of the variable capacitor after the occurrence of a state that satisfies the predetermined conditions, and generate calibrated reference data. With this configuration, the physical quantity measuring system of the present invention, based on measurement results at least two points, including a state in which no load or pressure is applied to the first member, allows the physical quantity measuring device or external PC, as described later, to generate reference data suitable for the actual characteristics of the variable capacitor at the time of on-site installation, including the initial characteristics of the variable capacitor, through regression analysis based on the first mathematical formula. Furthermore, the physical quantity measuring device or external PC can generate calibrated reference data while calibrating the reference data to suit the characteristics of the variable capacitor after the occurrence of a state that satisfies the conditions for calibrating the predetermined reference data, and based on the calibrated reference data and the detected data, it can appropriately measure the weight or pressure applied to the first member.As a result, with this configuration, the physical quantity measuring device can appropriately measure the load or pressure applied to the first member using appropriate reference data generated according to the actual characteristics of the variable capacitor at the time of on-site installation, including the initial characteristics of the newly installed variable capacitor. Furthermore, with this configuration, even if a condition arises after the variable capacitor has been installed and the system has started operation that satisfies predetermined conditions requiring calibration of the reference data, calibrated reference data suitable for the characteristics of the variable capacitor after the occurrence of such a condition can be generated, and the physical quantity measuring device can measure the weight or pressure applied to the first member using this calibrated reference data, thereby achieving appropriate physical quantity measurement. Whether or not a condition that satisfies predetermined conditions requiring calibration has occurred may be determined by the user, or it may be automatically determined by the physical quantity measuring device or an external PC that functions as a device for processing the calibration of the reference data. When the former method is adopted, the system determines that the user has met predetermined conditions requiring calibration of the reference data, such as when the user performs a periodic inspection, replaces at least a part of the elastic member, or applies a load or pressure exceeding a specified value. In such cases, the system measures the capacitance value of the variable capacitor using a capacitance sensor in at least two states, including (state 1) a state in which no load or pressure is applied to the first member, and (state 2) a state in which a known load or pressure is applied. The physical quantity measuring device then wirelessly acquires the measurement results from these at least two points from the capacitance sensor tag. Meanwhile, the physical quantity measuring device determines the values ​​of the first and second parameters suitable for the characteristics of the variable capacitor after the conditions have been met by performing a regression analysis based on the first mathematical formula on the acquired measurement results from these at least two points. Based on the values ​​of the first and second parameters determined in this way, the physical quantity measuring device calibrates the reference data to generate calibrated reference data suitable for the characteristics of the variable capacitor after the conditions have been met, and stores it for use in subsequent measurements.

[0027] Furthermore, if the latter method is adopted, the physical quantity measuring device may store, for example, the date and time of the previous reference data calibration or the date and time of the elastic member replacement. The physical quantity measuring device may then notify the user that a periodic inspection or replacement should be performed and the reference data calibrated when a predetermined period has elapsed from that date and time (for example, 6 months to 2 years in the case of periodic inspections, or 5 to 10 years from the date and time of the previous replacement in the case of elastic member replacement), prompting the user to perform the measurement work for calibration. In this case, the physical quantity measuring device may acquire detection data corresponding to at least two measurement results measured based on the calibration work performed by the user from the capacitance sensor tag 120 and calibrate the reference data. In addition, the detection data may be monitored to determine whether a load or pressure greater than specified has been applied, and if a capacitance value exceeding a predetermined threshold is detected, the physical quantity measuring device may determine that calibration is necessary and prompt the user to perform the calibration work.

[0028] (5) Furthermore, in the configuration described in claim 2, the physical quantity measuring device (A) when the variable capacitor is newly installed, obtains measurement results from at least two points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and determines the values ​​of the first and second parameters in the first formula that are suitable for the characteristics including the initial characteristics of the variable capacitor by calculation based on the third formula calculated based on the first formula on the measurement results, generates the reference data suitable for the characteristics including the initial characteristics of the variable capacitor based on the determined values ​​of the first and second parameters, and uses the reference data to apply to the first member (B) If a condition is met after the installation of the variable capacitor, the relationship between the load or pressure applied to the first member and the capacitance value of the variable capacitor is measured, and the values ​​of the first and second parameters in the first formula that are suitable for the characteristics of the variable capacitor after the condition is met are determined by calculation based on the third formula, the reference data is calibrated based on the determined values ​​of the first and second parameters to generate calibrated reference data that is suitable for the characteristics of the variable capacitor after the condition is met, and the load or pressure applied to the first member is measured using the calibrated reference data instead of the reference data generated at the time of initial installation.

[0029] As will be explained in detail later, one of the first and second parameters in the first formula can be determined based on the capacitance value of the variable capacitor when no load or pressure is applied to the first member. The other parameter can be easily calculated from the capacitance value measurement result based on a predetermined third formula (corresponding to (Formula 15) described later). As a result, with this configuration, when a new variable capacitor is installed, the physical quantity measuring device or external PC can determine the values ​​of the first and second parameters that are suitable for the actual characteristics of the variable capacitor at the time of on-site installation, including the initial characteristics of the variable capacitor, by performing a simple calculation based on two measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and the third formula, without performing calculations by regression analysis (nonlinear regression). The physical quantity measuring device can then apply the first and second parameters to generate reference data suitable for the characteristics of the variable capacitor. The physical quantity measuring device can then appropriately measure the load or pressure applied to the first member based on the reference data and the detected data. Furthermore, with this configuration, even if a condition arises after the variable capacitor has been installed and the system has started operation that necessitates calibration of the reference data, the physical quantity measuring device or external PC can determine the first and second parameters based on two measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and a third mathematical formula, without performing calculations by regression analysis (nonlinear regression), as described later. The physical quantity measuring device can then apply the determined first and second parameters to calibrate the reference data and generate calibrated reference data. As a result, this configuration dramatically reduces the processing burden required when generating reference data suitable for the actual characteristics of a newly installed variable capacitor, or when the characteristics of the variable capacitor change after the start of operation due to the occurrence of a condition that satisfies the above-mentioned predetermined conditions, necessitating calibration of the reference data. In this case as well, the occurrence of a condition that satisfies the conditions may be determined by the user, or it may be automatically determined by the physical quantity measuring device, and the calibration work itself is the same as described above.

[0030] (6) Furthermore, in the configuration described in claim 3, the physical quantity measuring device (A) when the variable capacitor is newly installed, obtains measurement results from at least three points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and determines the values ​​of the first to third parameters in the second formula that are suitable for the characteristics including the initial characteristics of the variable capacitor by regression analysis based on the second formula on the measurement results, generates the reference data suitable for the characteristics including the initial characteristics of the variable capacitor based on the determined values ​​of the first to third parameters, and uses the generated reference data to measure the load or pressure applied to the first member While measuring the value of (B) if a condition that satisfies predetermined conditions occurs after the installation of the variable capacitor, the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured and the measurement results of at least three points are obtained, and the values ​​of the first to third parameters in the second formula that are suitable for the characteristics of the variable capacitor after the condition occurs are determined by regression analysis based on the second formula on the measurement results, the reference data is calibrated based on the determined values ​​of the first to third parameters to generate calibrated reference data that is suitable for the characteristics of the variable capacitor after the condition occurs, and the value of the load or pressure applied to the first member is measured using the calibrated reference data instead of the reference data generated at the time of initial installation.

[0031] With this configuration, in the present invention, when a variable capacitor is newly installed, the first to third parameters suitable for the actual characteristics of the newly installed variable capacitor can be determined by regression analysis based on the second mathematical formula on at least three measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, for a physical quantity measuring device or external PC. Furthermore, when a condition satisfying the above predetermined conditions occurs, the physical quantity measuring device, etc., which performs calibration of the reference data, can appropriately determine the first to third parameters suitable for the characteristics of the variable capacitor after the characteristic change by regression analysis based on the second mathematical formula on the acquired at least three measurement results. As a result, the physical quantity measuring system of the present invention can appropriately measure the value of the load or pressure applied to the first member based on reference data and detection data suitable for the characteristics of the variable capacitor actually used. Moreover, with this configuration, even if a condition requiring calibration of the reference data occurs after the variable capacitor has been installed and the system has started operation, the physical quantity measuring device, etc., which performs calibration of the reference data can determine the first to third parameters suitable for the characteristics of the variable capacitor after the occurrence of the condition by regression analysis based on the second mathematical formula. Furthermore, the physical quantity measuring device can appropriately calibrate the reference data and generate calibrated reference data, and the physical quantity measuring device can appropriately measure the weight or pressure applied to the first member based on the calibrated reference data and the detected data. In this case as well, the occurrence of a condition that satisfies the conditions may be determined by the user, or the physical quantity measuring device may make an automatic determination, and the calibration work itself is the same as described above.

[0032] (7) Furthermore, in the configuration described in claim 3, the physical quantity measuring device (A) when the variable capacitor is newly installed, obtains measurement results from at least three points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and based on the measurement results, determines the values ​​of the first to third parameters in the second formula that are suitable for the characteristics including the initial characteristics of the variable capacitor based on a predetermined group of formulas, generates the reference data suitable for the characteristics including the initial characteristics of the variable capacitor based on the determined values ​​of the first to third parameters, and uses the reference data to determine the value of the load or pressure applied to the first member While taking measurements, (B) if a condition that satisfies predetermined conditions occurs after the installation of the variable capacitor, the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured and the measurement results of at least three points are obtained, and based on the measurement results, the values ​​of the first to third parameters in the second formula that are suitable for the characteristics of the variable capacitor after the condition occurs are determined based on the predetermined group of formulas, and the reference data is calibrated based on the determined values ​​of the first to third parameters to generate calibrated reference data that is suitable for the characteristics of the variable capacitor after the condition occurs, and the value of the load or pressure applied to the first member is measured using the calibrated reference data instead of the reference data generated at the time of initial installation.

[0033] With this configuration, when a variable capacitor is newly installed in the present invention, a physical quantity measuring device that generates reference data acquires at least three measurement results, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member. The physical quantity measuring device then determines the values ​​of the first to third parameters that are suitable for the actual characteristics of the variable capacitor, including its initial characteristics, based on a predetermined set of mathematical formulas (specifically, formulas 18 to 20 described later), and generates reference data that is suitable for the actual characteristics of the variable capacitor at the time of on-site installation, including its initial characteristics. With this configuration, the physical quantity measuring system of the present invention can appropriately measure the value of the load or pressure applied to the first member based on the generated reference data and the detection data. Furthermore, with this configuration, if a calibration gap in the reference data occurs after the system has started operation, the physical quantity measuring device acquires three measurement results, which are the actual measurement results of the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member. Then, the physical quantity measuring device can determine the values ​​of the first to third parameters that are suitable for the characteristics of the variable capacitor after the occurrence of the condition, based on the predetermined set of mathematical formulas, and appropriately calibrate the reference data based on the determined values ​​of the first to third parameters to generate calibrated reference data. As a result, with this configuration, the physical quantity measuring device can generate reference data suitable for the actual characteristics, including the initial characteristics of a newly installed variable capacitor, through simple calculations, and use it for measurement. Furthermore, it can appropriately calibrate the reference data to match the characteristics of the variable capacitor after the conditions are met, and measure the value of the load or pressure applied to the first member based on the configured reference data to achieve highly accurate physical quantity measurement. In this case as well, the occurrence of a condition that satisfies the conditions may be determined by the user, or it may be determined automatically by the physical quantity measuring device, and the calibration work itself is the same as described above.

[0034] (8) In addition, in the configuration described in any one of claims 1 to 7, a plurality of physical quantity detection devices, each composed of a variable capacitor and a capacitance sensor, are installed at different locations in real space, and the physical quantity measuring device has a storage means that stores the reference data or calibrated reference data corresponding to each of the plurality of physical quantity detection devices in association with identification information for identifying the physical quantity detection device, and a configuration is adopted in which (a1) detection data corresponding to the capacitance value of the variable capacitor constituting the physical quantity detection device, and (a2) the identification information corresponding to the physical quantity detection device are acquired wirelessly from each of the capacitance sensors constituting the plurality of physical quantity detection devices in association with (a1) the detection data, which is the variable capacitor constituting the physical quantity detection device, and (a2) the identification information corresponding to the physical quantity detection device, and (b1) the detection data acquired in association with the identification information, and (b2) the reference data or calibrated reference data stored in the storage means in association with the acquired identification information, the value of the load or pressure applied to the first member of each physical quantity detection device is measured individually, and processing based on the measurement results is performed.

[0035] With this configuration, the physical quantity measurement system of the present invention allows for the individual measurement and centralized management of the weight or pressure applied to the first component constituting the variable capacitor of each physical quantity detection device when multiple physical quantity detection devices, each composed of a variable capacitor and a capacitance sensor, are installed in different locations in a real space such as a warehouse, store, or indoor / outdoor exhibition hall (for example, various locations within a warehouse or various locations within a store). As a result, with this configuration, for example, when multiple physical quantity detection devices are installed in a facility such as a warehouse or store, and each physical quantity detection device manages the inventory status of different products, the inventory of multiple types of products managed by each physical quantity detection device can be centrally managed by a single physical quantity measurement device.

[0036] (9) In addition, in the configuration described in claim 8, the storage means may store product attribute information indicating the attributes of the product whose inventory is managed using the corresponding physical quantity detection device, in association with the identification information and the reference data, and the physical quantity measuring device may, based on the acquired detection data and the reference data or calibrated reference data corresponding to the physical quantity detection device that is the source of the acquisition of the detection data, measure the load applied to the first member as the weight value of the product whose inventory is managed using the physical quantity detection device, and execute a process to manage the inventory of the product which is managed using each physical quantity detection device based on the measured load and the product attribute information of the corresponding product stored in the storage means.

[0037] With this configuration, the physical quantity measurement system of the present invention can accurately and appropriately manage the inventory status of multiple types of products with a single physical quantity measurement device when multiple physical quantity detection devices are installed in a facility such as a warehouse, store, or indoor / outdoor exhibition hall (corresponding to the above-mentioned site), and each physical quantity detection device manages the inventory of different products. For example, it can (a) issue an alert when additional orders are needed, or (b) execute automatic ordering of the necessary products.

[0038] (10) In addition, in the configuration described in any one of claims 1 to 7, the capacitance sensor may be configured as an RFID tag, and may generate an electromotive force based on electromagnetic waves transmitted by the physical quantity measuring device or other device, or a magnetic field generated by the information processing device or other device, and use the electromotive force to detect the capacitance value of the variable capacitor and wirelessly transmit the detection data corresponding to the detection result to the physical quantity measuring device.

[0039] This configuration eliminates the need to provide a power supply for the capacitance sensor in the physical quantity measurement system of the present invention. As a result, the weight or pressure value applied to the first component of the variable capacitor can be monitored for a very long period of time without replacing the capacitance sensor's battery, significantly reducing both the initial cost of system construction and the running cost of system operation.

[0040] (11) In addition, in the configuration described in claim 8, the capacitance sensor may be configured as an RFID tag, and may generate an electromotive force based on electromagnetic waves transmitted by the physical quantity measuring device or other device, or a magnetic field generated by the information processing device or other device, and use the electromotive force to detect the capacitance value of the variable capacitor and wirelessly transmit the detection data corresponding to the detection result to the physical quantity measuring device.

[0041] This configuration can achieve the same effects as those described in claim 10.

[0042] (12) The capacitance sensor described in claim 9 may also be configured as an RFID tag, which generates an electromotive force based on electromagnetic waves transmitted by the physical quantity measuring device or other device, or a magnetic field generated by the information processing device or other device, and uses the electromotive force to detect the capacitance value of the variable capacitor and wirelessly transmit the detection data corresponding to the detection result to the physical quantity measuring device.

[0043] This configuration can achieve the same effects as those described in claim 10.

[0044] (13) Furthermore, the physical quantity detection device of the present invention comprises two members connected opposite to each other by an elastic member, (1) a first member which is installed to be movable when a load or pressure is applied and which has a movable electrode disposed thereon, and (2) a second member which has a fixed electrode disposed at a position opposite to the movable electrode and which does not move even when a load or pressure is applied to the first member and is fixed thereon, and the elastic member elastically deforms according to the applied load or pressure, and a variable capacitor whose capacitance value changes due to the change in the distance between the movable electrode and the fixed electrode when the first member moves, and a device electrically connected to the variable capacitor which detects the capacitance value of the variable capacitor and generates corresponding detection data, and the detection data is ( a) A capacitance sensor wirelessly transmits to a physical quantity measuring device that measures the value of the load or pressure applied to the first member using reference data generated by performing calculations based on a first mathematical formula that includes unknown first and second parameters and defines the relationship between the capacitance value of the variable capacitor and the load or pressure applied to the first member, using reference data that determines the values ​​of the first and second parameters suitable for the characteristics of the variable capacitor, based on measurement results at least two points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member.

[0045] With this configuration, the physical quantity detection device of the present invention can convert the load or pressure applied to the first member of a variable capacitor, which functions as a sensor, into a capacitance value using the variable capacitor, and transmit the corresponding detection data to the physical quantity measuring device. On the other hand, the physical quantity measuring device can measure the value of the load or pressure applied to the first member using (1) reference data suitable for the actual characteristics at the time of on-site installation, including the initial characteristics of the variable capacitor, or (2) calibrated reference data obtained by calibrating this reference data based on the two measurement results described above. This reference data is generated by performing calculations based on a first mathematical formula on the measurement results, which include the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and (2) calibrated reference data obtained by calibrating this reference data based on the two measurement results described above. At this time, the physical quantity measuring device can measure the value of the load or pressure applied to the first member based on the reference data or calibrated reference data and the detection data wirelessly transmitted from the physical quantity detection device. Furthermore, the calculation methods for generating and calibrating the reference data are the same as in the physical quantity measurement system described above. (Calculation Method 1) Similar to the configuration of Claim 2, a method can be adopted in which the values ​​of the first and second parameters are determined by calculation based on a first mathematical formula using at least two measurement results, including the measurement result of the capacitance value when no load or pressure is applied to the first member. Also, (Calculation Method 2) Similar to the configuration of Claim 3, a method can be adopted in which the values ​​of the first to third parameters are determined by calculation based on a second mathematical formula using at least three measurement results, including the measurement result of the capacitance value when no load or pressure is applied to the first member. Furthermore, in the physical quantity measurement device of the present invention, methods similar to those in Claims 4 to 7 can also be adopted, but the specific actions and effects when each method is adopted are the same as in the physical quantity measurement system, so the details are omitted.

[0046] As a result, the physical quantity detection device of the present invention can remotely measure physical quantities such as the weight (load) of an object placed on the first member of a variable capacitor that functions as a load or pressure sensor, or the pressure applied to the first member of the variable capacitor, using a physical quantity measuring device, and the physical quantity measuring device can perform various processes using the measurement results. Furthermore, the variable capacitor that functions as a load or pressure sensor can be constructed very simply and at low cost by connecting a first member on which a movable electrode is provided and a second member on which a fixed electrode is provided with an elastic member so that the movable electrode and the fixed electrode are facing each other. In addition, the capacitance sensor can be configured as, for example, an RFID that can be manufactured at low cost, or as a capacitance tester with wireless communication functionality, so that the capacitance value of the variable capacitor obtained by converting the load or pressure value applied to the first member of the variable capacitor (sensor) can be detected at low cost and transmitted wirelessly to the physical quantity measuring device. Accordingly, the physical quantity detection device of the present invention can measure the load or pressure applied to the first component of a variable capacitor, which functions as a sensor, using a physical quantity measuring device installed at a location distant from the installation location of the variable capacitor, which functions as a sensor, in a very simple configuration and at low cost, and can also perform various processes using the measurement results. The various processes that can be performed by the physical quantity measuring device are the same as those in the case of a physical quantity measuring system.

[0047] The physical quantity measurement system according to the present invention can detect physical quantities such as the weight (load) of an object placed on a sensor or the pressure applied to the sensor with a simple configuration, and measure them remotely.

[0048] This is a system configuration diagram showing an example of the configuration of the weight measurement system of the first embodiment. This is a diagram showing an example of the configuration of the weight detection device of the first embodiment. (A) is a perspective view of the variable capacitor constituting the weight detection device, and (B) is a cross-sectional view of the variable capacitor when no object to be measured is placed on the mounting part provided on the top of the variable capacitor, viewed from the direction of "X" in (A), and shows the connection state of the capacitance sensor tag to the variable capacitor. (C) is an example of a cross-sectional view of the variable capacitor when an object to be measured is placed on the mounting part, viewed from the direction of "X", and shows the connection state of the capacitance sensor tag to the variable capacitor. This is a diagram showing the configuration of the upper plate and lower plate constituting the variable capacitor of the first embodiment, with (A) being a perspective view of the upper plate and (B) being a perspective view of the lower plate. This is a graph showing the measurement results of the average spring length of the coil spring when a weight of known weight is placed on the mounting part of the variable capacitor of the first embodiment. This graph shows the measurement results of the capacitance value of the variable capacitor detected by the capacitance sensor tag when a weight of known weight was placed on the mounting part of the variable capacitor of the first embodiment, and the approximation curve obtained from regression analysis based on the said measurement results. This figure is for explaining the calibration method adopted in the weight measurement system of the first embodiment, with (A) showing the two-point measurement method for calibration and (B) showing the characteristic curve obtained by calibration. This is a table showing the results of a verification experiment to verify whether the calibration was properly performed in the weight measurement system of the first embodiment. This is a system configuration diagram showing an example of the configuration of the weight measurement system of the third embodiment. This figure shows the configuration of the upper plate and lower plate that constitute the variable capacitor of the third embodiment, with (A) showing a perspective view of the upper plate and (B) showing a perspective view of the lower plate. This graph shows the measurement results of the average spring length of the Z-shaped leaf spring when a weight of known weight was placed on the mounting part of the variable capacitor of the third embodiment. This graph shows the measurement results of the capacitance value of the variable capacitor of the third embodiment measured using the same method as in Figure 5. (A) is a scatter plot of the measurement results, and (B) is a graph showing the regression curve obtained by performing curve fitting using the nonlinear least squares method with (Equation 11) along with the measurement results.This graph displays the regression curve obtained by performing curve fitting using the nonlinear least squares method with (Equation 16) on the measurement results (measurement results in Figure 10(A)) of the relationship between the weight and capacitance value when a weight of known weight is placed on the mounting part of the variable capacitor of the third embodiment, along with the measurement results. This figure is for explaining the calibration method adopted in the weight measurement system of the third embodiment. (A) shows the three-point measurement method for calibration, and (B) shows the characteristic curve obtained by calibration. This figure is a diagram showing an example of data storage in the product inventory management DB stored in the storage unit of the information processing device of the fourth embodiment. This is a flowchart showing the processing performed in the information processing device of the fourth embodiment. This shows the approximate curve obtained when two-point calibration is performed using the variable capacitor of Modification 2 according to the present invention. This figure shows the configuration of the upper plate and lower plate constituting the variable capacitor of Modification 5 according to the present invention, where (A) is a perspective view of the lower plate and (B) is a perspective view of the upper plate.

[0049] Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are examples of applying the physical quantity measurement system according to the present invention to a system for measuring the weight (i.e., load) of an object to be measured. However, the embodiments described below are not intended to unduly limit the content of the present invention as described in the claims, and not all of the configurations described in the following embodiments are necessarily essential components of the present invention. Furthermore, the embodiments described below will be explained using the case of measuring the weight of an object to be measured as an example, but the physical quantity measured in the physical quantity measurement system of the present invention is arbitrary and can be applied to measuring physical quantities other than the weight of an object to be measured, such as pressure. Strictly speaking, "weight" and "mass" are fundamentally different concepts. However, mass and weight can be converted by multiplying by or dividing by the acceleration due to gravity. Therefore, in this application, measuring "weight" and measuring "mass" are considered to be equivalent. Furthermore, while the units of weight are originally "N (Newton)," "gf (gram-force)," and "kgf (kilogram-force)," in this specification, for the sake of ease of understanding the invention, they will be simply expressed as "g" and "kg."

[0050] [A] First Embodiment [A1] Overall Configuration and Overview of Weight Measurement System 1 First, the configuration and overview of the weight measurement system 1 of this embodiment will be described using Figure 1. Figure 1 is a system configuration diagram showing an example of the configuration of the weight measurement system 1 of this embodiment.

[0051] As shown in Figure 1, the weight measurement system 1 of this embodiment comprises a weight detection device 10 comprising (a1) a mounting section 111 for placing an object to be measured (hereinafter also referred to as "object to be measured MO"), a variable capacitor 110 whose capacitance changes according to the weight of the object to be measured MO placed on it, and (a2) a capacitance sensor tag 120 electrically connected to the variable capacitor 110 and detecting the capacitance value of the variable capacitor 110, (1b) an RFID reader / writer 20, and (c) an information processing device 30 such as a PC (personal computer), smartphone, or tablet-type information and communication terminal device. The weight measurement system 1 of this embodiment converts the weight (load) of the object to be measured MO placed on the mounting section 111 into a capacitance value using the variable capacitor 110, and measures the weight of the object to be measured MO using the information processing device 30 based on the capacitance value. The weight measurement system 1 of this embodiment notifies the user of the measurement result using at least one of voice and / or images, or performs processing based on the measurement result. For example, the weight detection device 10 and the information processing device 30 of this embodiment constitute the "physical quantity detection device" and the "physical quantity measurement device" of the present invention, respectively.

[0052] In the conventional capacitive electronic scales and sensors described above (for example, in Patent Documents 1 and 2), the weight or pressure detected by a parallel plate capacitor-type sensor, which consists of a fixed electrode and a movable electrode arranged opposite each other, is displayed on a display device electrically connected to the sensor. Therefore, it is difficult to check or manage the weight of the object being measured or the physical quantity such as the pressure applied to the sensor from a location far from where the sensor is installed. On the other hand, according to the configuration described in Patent Document 3, the physical quantity such as the load or pressure applied to the sensor can be displayed, checked, and managed remotely. However, this method involves configuring a sensor by combining multiple RFIDs equipped with switches with different on / off thresholds, and detecting the range of the load or pressure applied to the sensor. Therefore, the method described in Patent Document 3 not only makes the sensor complex and large, but if you want to measure the load or pressure precisely, the number of switches and RFIDs required increases, making the device complex and large, and making it difficult to reduce the cost of the device.

[0053] Therefore, in the weight measurement system 1 of this embodiment, a mounting section 111 is provided, and a single capacitive sensor tag 120, configured as a passive RFID, is electrically connected to a variable capacitor 110 that functions as a load sensor to constitute the weight detection device 10. Then, an RFID reader / writer 20 supplies electromagnetic waves to the capacitive sensor tag 120, and based on these electromagnetic waves, the capacitive sensor tag 120 generates an electromotive force and uses this electromotive force to detect the capacitance value of the variable capacitor 110. The capacitive sensor tag 120 wirelessly transmits detection data corresponding to the capacitance value detected in this way to the RFID reader / writer 20. For example, if the capacitive sensor tag 120 and RFID reader / writer 20 transmit and receive electromagnetic waves in the HF (High Frequency) band, the capacitive sensor tag 120 can generate an electromotive force based on the magnetic field generated by the RFID reader / writer 20, use that electromotive force to measure the capacitance value of the variable capacitor 110, and transmit the detection data to the information processing device 30.

[0054] On the other hand, in this embodiment, the information processing device 30 measures the weight of the object to be measured MO placed on the mounting unit 111 based on (a) detection data acquired from the capacitive sensor tag 120 via the RFID reader / writer 20 and (b) measurement reference data stored in the device beforehand. The information processing device 30 then notifies the user of the measurement result using at least one of voice and / or images, or performs processing based on the measurement result. For example, the measurement reference data in this embodiment corresponds to the "reference data" of the present invention, but this measurement reference data will be described in detail later. With this configuration, the user can confirm the weight of the object to be measured MO using the information processing device 30 which is installed in a location separate from the weight detection device 10. In addition, the information processing device 30 which is installed in a location separate from the weight detection device 10 can manage the weight change of the object to be measured MO placed on the mounting unit 111. As a result, with this configuration, for example, the number of goods in stock placed on storage shelves for inventory management installed in facilities such as warehouses, stores, and indoor and outdoor exhibition halls can be managed by an information processing device 30 installed in a management room or office located inside or outside the warehouse or store. In this embodiment, the explanation will be given as an example in which the information processing device 30 is installed in a management room or office inside or outside the warehouse, and weight detection devices 10 are installed on storage shelves, inventory management pallets, storage boxes, storage baskets, etc., installed in facilities such as warehouses, stores, and exhibition halls, thereby realizing the function of managing the inventory of goods stored and managed within the warehouse or other facilities using the information processing device 30. However, the specific processing content to be executed by the information processing device 30 based on the measurement results is arbitrary. For example, the information processing device 30 may simply display the measurement result of the weight of the object to be measured MO, or it may be configured to notify the user of the measurement result using at least one of voice and images. Also, the number of weight detection devices 10 managed by the information processing device 30 is arbitrary. Therefore, a configuration may be adopted in which multiple weight detection devices 10 are centrally managed by a single information processing device 30, and the inventory of multiple types of products is centrally managed by the information processing device 30. However, in this embodiment, the explanation will be given as an example in which only one weight detection device 10 is managed by the information processing device 30 and only the inventory quantity of one type of product is managed.Furthermore, a method for managing multiple weight detection devices 10 with a single information processing device 30, and for centrally managing the inventory of multiple types of products with a single information processing device 30, will be described in a later embodiment. In addition, the capacitive sensor tag 120 may use any of the following drive methods: active, passive, semi-active, or semi-passive. However, in this embodiment, the explanation will assume the use of a passive drive method, and the cases where active or semi-active drive methods are adopted will be explained in the section on modifications. With this configuration, there is no need to provide a power supply for the capacitive sensor tag 120, so the weight of the object MO placed on the mounting unit 111 can be measured, managed, and monitored for a very long period of time without replacing the battery of the capacitive sensor tag 120. As a result, the weight measurement system 1 of this embodiment can significantly reduce the initial cost of system construction and the running cost of system operation. Furthermore, with this configuration, there is no need to provide a power supply for the capacitive sensor tag 120, so the weight of the object to be measured MO can be measured without being affected by the ambient temperature during use (also called the "operating environment temperature"). As a result, the weight measurement system 1 of this embodiment can manage the inventory of goods in a cold storage warehouse at a very low cost, even in situations such as installing the weight detection device 10 in a cold storage warehouse at around -22°C to manage the inventory of goods in the cold storage warehouse.

[0055] [A2] Specific Configuration of Weight Detection Device 10 and Variable Capacitor 110 Next, the configuration of the weight detection device 10 and variable capacitor 110 of this embodiment will be explained with reference to Figures 2 and 3. Figure 2 is a diagram showing an example of the configuration of the weight detection device 10 of this embodiment. (A) shows a perspective view of the variable capacitor 110 that constitutes the weight detection device 10. (B) shows a cross-sectional view of the variable capacitor 110 when the object to be measured MO is not placed on the mounting part 111 provided on the upper part of the variable capacitor 110, viewed from the direction of "X" in (A), and illustrates the connection state of the capacitance sensor tag 120 to the variable capacitor 110. Furthermore, (C) shows a cross-sectional view of the variable capacitor 110 when the object to be measured MO is placed on the mounting part 111, viewed from the direction of "X" above, and illustrates the connection state of the capacitance sensor tag 120 to the variable capacitor 110. Figure 3 is a diagram showing the configuration of the upper plate 112 and lower plate 115 that constitute the weight detection device 10 and variable capacitor 110 of this embodiment. (A) is a perspective view of the upper plate 112, and (B) is a perspective view of the lower plate 115. In Figure 3, the upper plate 112 and lower plate 115 are shown as viewed from the electrode mounting surfaces 112A and 115A, which will be described later (that is, perspective views of the upper plate 112 and lower plate 115 as viewed from the midpoint between the upper plate 112 and lower plate 115 in the variable capacitor 110).

[0056] As shown in Figures 1 to 3, the variable capacitor 110 constituting the weight detection device 10 of this embodiment has a configuration in which copper foil is provided on an insulating substrate such as FR4 (Flame Retardant Type 4), and has an upper plate 112 on which a mounting portion 111 is installed on one side, and a lower plate 115 made of the same substrate as the upper plate 112 and fixed to a fixed object such as a floor, desk, or shelf side plate, with four metal coil springs CS1 to 4 (hereinafter referred to as "coil spring CS" when it is not necessary to specifically identify each coil spring) which function as an elastic body sandwiched in parallel between the upper plate 112 and the lower plate 115. Furthermore, the type and shape of the elastic body sandwiched between the upper plate 112 and the lower plate 115 are arbitrary; for example, a metal leaf spring, sponge, rubber, etc., may be used. Moreover, even when coil springs are used as the elastic body as in this embodiment, the number of springs sandwiched between the two (i.e., the upper plate 112 and the lower plate 115) is arbitrary. Therefore, a configuration with five coil springs sandwiched between them is possible, or a configuration with four or fewer coil springs sandwiched between them is also possible. However, in this embodiment, in order to make the explanation more concrete, four coil springs CS1 to CS4 are positioned in the four corner areas of the upper plate 112, and the coil springs CS1 to CS4 are sandwiched between the two 112 and 115, and the upper plate 112 and the lower plate 115 are connected by the coil springs CS1 to CS4 (see Figures 2 and 3). Cases using leaf springs and cases in which five coil springs are sandwiched and the two 112 and 115 are connected by the five coil springs will be described in detail in the sections on other embodiments and modifications.

[0057] Furthermore, in this embodiment, on the upper plate 112 opposite to the side on which the mounting portion 111 is installed (hereinafter also referred to as the "electrode installation surface 112A"), a movable electrode 113 made of metal (for example, copper) with an area of ​​"S1" and a thickness of "several tens of micrometers" is provided in a predetermined area including the center of the upper plate 112 (see Figures 2 and 3(A)). In contrast, on one side of the lower plate 115 (hereinafter also referred to as the "electrode installation surface 115A"), (a) a first fixed electrode 114A made of metal (for example, copper) with a thickness of "several tens of micrometers" and an area "S2" equivalent to the area "S1" of the movable electrode 113 is provided in an area including the center of the lower plate 115. Furthermore, (b) in the region of the electrode mounting surface 115A where any of the coil springs CS1 to CS4 make contact (in the example shown in Figure 3, the region where coil spring CS3 makes contact), a second fixed electrode 114B made of metal (for example, copper) is provided, which is electrically insulated from the first fixed electrode 114A, has an area "S3" smaller than area "S2", and has a thickness of "several tens of micrometers" (see Figures 1, 2, and 3(B)). Note that in the configurations shown in Figures 1 to 3, a solder resist film RF (hereinafter referred to as "resist film RF") with a thickness of "10 μm" is provided on the movable electrode 113 and the first fixed electrode 114A as an example for electrode protection. However, when creating the actual device, this resist film RF may be removed (see Figure 3), or the variable capacitor 110 may be configured with the resist film RF remaining for electrode protection. Even if the resist film RF is left intact, the resist film RF is very thin, so its influence on the capacitance value of the variable capacitor 110 can be ignored.

[0058] In the variable capacitor 110 of this embodiment, the positions of the upper plate 112 and the lower plate 115 are adjusted so that (1) the movable electrode 113 and (2) the first and second fixed electrodes 114A and 114B are opposite each other across four coil springs CS1 to 4 which are installed in parallel. In addition, in the variable capacitor 110 of this embodiment, the first and second fixed electrodes 114A and 114B are electrically connected to the first input terminal 120A and the second input terminal 120B of the capacitance sensor tag 120, respectively (see Figures 1 to 3). Note that in Figures 1 and 2, the variable capacitor 110 and the capacitance sensor tag 120 are formally shown as separate components to facilitate understanding of the connection state between the variable capacitor 110 and the capacitance sensor tag 120. However, as illustrated in Figures 2(A) and 3(B), the capacitance sensor tag 120 may be incorporated into the lower plate 115 of the variable capacitor 110 and built into the lower plate 115, or it may be a separate component as illustrated in Figures 1 and 2. In either case, the configuration should be such that the first and second fixed electrodes 114B are electrically connected to the first and second input terminals 120A and 120B of the capacitance sensor tag 120, respectively. In this embodiment, for the purpose of making the explanation more concrete, the explanation will be given assuming that the IC (Integrated Circuit) chip ICC and antenna AN constituting the capacitance sensor tag 120 are incorporated into a part of the lower plate 115 of the variable capacitor 110, and the capacitance sensor tag 120 is built into the lower plate 115 (see Figure 3(B)). That is, in this embodiment, the variable capacitor 110 alone realizes all the functions of the weight detection device 10, and the variable capacitor 110 and the weight detection device 10 are considered to be substantially the same. This configuration allows the variable capacitor 110 to function as a weight detection device 10 on its own, thus enabling miniaturization of the weight detection device 10 and improving the flexibility of installation when installing the weight detection device 10 in facilities such as warehouses and stores. It is also possible to incorporate the IC chip ICC and antenna AN of the capacitive sensor tag 120 into the top plate 112, thereby integrating the capacitive sensor tag 120 into the top plate 112.However, in this case, the configuration of the electrodes and the connection method of the electrodes to the first and second input terminals 120A and 120B of the capacitance sensor tag 120 will change from the configuration shown in Figures 1 to 3, and this will be described in detail in the section on modifications. Furthermore, in the variable capacitor 110 of this embodiment, the movable electrode 113 and the second fixed electrode 114B are electrically connected by a conductive coil spring CCS (see Figures 1, 2(B) and (C)). Note that any of the coil springs CS1 to 4 as elastic members may be used as the conductive coil spring CCS, but Figure 3 shows an example where coil spring CS3 is used as the conductive coil spring CCS. Furthermore, a gold flash GF of approximately 100 nm (nanometers) in thickness is applied to the areas where the conductive coil spring CCS (coil spring CS3 in Figure 3(C)) contacts the movable electrode 113 and the second fixed electrode 114B, in order to protect both electrodes 113 and 114B and to improve conductivity. In Figure 3(A), an example configuration is shown in which a region of gold flash GF is applied to the lower plate 115 at a position slightly away from the movable electrode 113 so as to be opposite the second fixed electrode 114B. However, when setting the area "S1 to S3" of each electrode so that the second fixed electrode 114B and the movable electrode 113 are opposite each other, the gold flash GF on the movable electrode 113 side should be applied to the region of the movable electrode 113 that is opposite the second fixed electrode 114B. Furthermore, in the example shown in Figure 3(A), a region where gold flash GF is applied is formed at a position separate from the movable electrode 113, but it is preferable not to include the area of ​​this region in the area "S1".

[0059] Furthermore, in this embodiment, the upper plate 112 and lower plate 115 are provided with fixing means (not shown) at the contact points of each coil spring CS1 to 4 to fix the corresponding coil spring CS to the upper plate 112 and lower plate 115 and connect them. This fixing means secures the coil spring CS sandwiched between the upper plate 112 and lower plate 115, preventing the coil spring CS from shifting during system operation, which would reduce measurement accuracy, and also prevents rattling of the variable capacitor 110. For example, adhesives or glues can be used for this fixing means, but in this embodiment, double-sided tape with a thickness of approximately 100 μm is used to facilitate the reinstallation of the variable capacitor 110. However, with respect to the conductive coil spring CCS (for example, coil spring CS3), it is necessary for the gold flash GF applied on the movable electrode 113 and the second fixed electrode 114B to be in direct contact with the conductive coil spring CCS and electrically connected. Therefore, the fixing means for the part that fixes the conductive coil spring CCS to the gold flash GF is, for example, to fix the gold flash GF of the movable electrode 113 and the second fixed electrode 114B in a state where both gold flash GF and the conductive coil spring CCS can conduct electricity, by means of conductive adhesive or soldering. When actually constructing the variable capacitor 110, the upper plate 112 is placed on the lower plate 115 while the electrode mounting surfaces 112A and 115A are facing each other so that the gold flash GF of the movable electrode 113 provided on the upper plate 112 shown in Figure 3(A) and the conductive coil spring CCS (coil spring CS3) shown in Figure 3(B) are in contact. At this time, the positions of the upper plate 112 and the lower plate 115 are adjusted so that the movable electrode 113 and the first and second fixed electrodes 114A and 114B are in a position to face each other. Then, the coil springs CS1 to CS4 are placed on the lower plate 115, which is fixed in the aligned position, and the upper plate 112 is placed over it. The upper plate 112 and each coil spring CS1 to CS4 are then fixed together by fixing means to construct the variable capacitor 110 (see Figures 1 and 2). As a result, the coil springs CS1 to CS4 are sandwiched between the upper plate 112 and the lower plate 115, and are fixed (connected) to the upper plate 112 and the lower plate 115 by fixing means provided on the upper plate 112 and the lower plate 115, thereby constructing the variable capacitor 110.

[0060] With this configuration, in the weight detection device 10 of this embodiment, (1) the first fixed electrode 114A is electrically connected to the first input terminal 120A of the capacitance sensor tag 120 built into the lower plate 115. On the other hand, (2) the movable electrode 113 is electrically connected to the second input terminal 120B of the capacitance sensor tag 120 via the second fixed electrode 114B, the conductive coil spring CCS, and the two layers of gold flash GF. As a result, in the weight detection device 10 of this embodiment, the movable electrode 113 on the upper plate 112 side and the first fixed electrode 114A on the lower plate 115 side, which are in opposing positions with the four coil springs CS1 to 4 in between, function as a parallel plate capacitor. The movable electrode 113 and upper plate 112 that constitute this parallel plate capacitor, and the first fixed electrode 114A and lower plate 115 constitute the variable capacitor 110 of this embodiment.

[0061] As a result, in the weight detection device 10 that constitutes the weight measurement system 1 of this embodiment, when the object to be measured MO is placed on the placement section 111, (a) the lower plate 115 fixed to the fixed object does not move. On the other hand, (b) the coil springs CS1 to CS4 sandwiched between the upper plate 112 and the lower plate 115 compress (i.e., elastically deform) in accordance with the weight of the object to be measured MO placed on the placement section 111, and the upper plate 112 moves towards the lower plate 115 side in accordance with the weight of the object to be measured MO placed on it (i.e., sinks to the lower side in the drawings of Figures 1 and 2). As a result, in the variable capacitor 110 of this embodiment, the distance between the electrodes between the movable electrode 113 and the first fixed electrode 114A changes, and the capacitance value changes accordingly. For example, the example shown in Figure 2 illustrates the case when the distance between the electrodes changes from "x1" to "x2" in accordance with the weight of the object to be measured MO. Note that "x1" and "x2" shown in Figure 2 are defined as the distance between the FR4 of the upper plate 112 and the lower plate 115. However, the movable electrode 113, the first and second fixed electrodes 114A and 14B are each about "several tens of micrometers" thick, the resist film RF is about "10 micrometers" thick, and the double gold flash GF is each about "100 nm" thick. Furthermore, the double-sided tape used as a fixing means in the prototype of the actual device is about "100 micrometers" thick, so the influence of these thicknesses on the distance between electrodes is very small and can be ignored. Therefore, in this configuration, the distance between the FR4 of the upper plate 112 and the lower plate 115 can be considered as the distance between electrodes. In this embodiment, the capacitance sensor tag 120 detects the capacitance value of the variable capacitor 110 which changes according to the weight placed on it, generates corresponding detection data, and wirelessly transmits it to the information processing device 30.

[0062] Meanwhile, the information processing device 30 measures the weight of the object to be measured MO placed on the mounting unit 111 based on the detection data and measurement reference data transmitted from the capacitance sensor tag 120 in this manner, and performs processing based on the measurement results. Depending on the setting values ​​of the position and area "S1" of the movable electrode 113 and the arrangement position and area "S3" of the second fixed electrode 114B, the movable electrode 113 and the second fixed electrode 114B may be in positions opposite each other in at least part, as illustrated in Figures 1 to 3. However, the second fixed electrode 114B is configured to be electrically connected (short-circuited) to the movable electrode 113 by a conductive coil spring CCS. Therefore, even in such a case, the movable electrode 113 and the second fixed electrode 114B do not constitute a parallel plate capacitor with the movable electrode 113, and the variable capacitor 110 is constructed only by the movable electrode 113 and the first fixed electrode 114A. As a result, in this embodiment, the first fixed electrode 114A functions as the "fixed electrode" of the present invention. As mentioned above, any of the four coil springs CS1 to CS4 may be used for the conductive coil spring CCS. In this case, the coil spring CS that becomes the conductive coil spring CCS (for example, coil spring CS3) fulfills both the function of (i) an elastic member that supports the upper plate 112 and (ii) a wiring that provides conductivity between the movable electrode 113 and the second fixed electrode 114B. On the other hand, the other coil springs CS (coil springs CS1, 2, and 4 in the case of Figure 3) are electrically insulated from each electrode 113, 114A, and 114B, and simply function as elastic members that support the upper plate 112 while connecting the upper plate 112 and the lower plate 115.

[0063] Furthermore, in this embodiment, in order to simplify the device configuration and reduce the manufacturing cost of the variable capacitor 110, one of the coil springs CS1 to CS4 (coil spring CS3 in the example shown in Figure 3) sandwiched between the upper plate 112 and the lower plate 115 is used as a conductive coil spring CCS. In this configuration, the movable electrode 113 is described as being electrically connected to the second fixed electrode 114B and the second input terminal 120B of the capacitance sensor tag 120. However, the second input terminal 120B may be electrically connected directly to the movable electrode 113 by a conductive wire or the like, or the second fixed electrode 114B, which is electrically connected to the second input terminal 120B, and the movable electrode 113 may be electrically connected by a conductive wire. In this case, it is desirable that the conductive wire be appropriately fixed to the movable electrode 113 and the second fixed electrode 114B or the second input terminal 120B by a method such as soldering. Furthermore, it is possible to replace the coil springs CS1 to CS4 by inserting four metal Z-shaped leaf springs (leaf springs LS1 to LS4, described later) between the upper plate 112 and the lower plate 115. In this case, any of the leaf springs (leaf spring LS3 in the case shown in Figure 9, described later) can be used for conductivity between (1) the movable electrode 113 and (2) the second fixed electrode 114B connected to the second input terminal 120B (i.e., corresponding to the conductive coil spring CCS), but this point will be explained in a later embodiment. Note that in addition to the configuration in which the capacitance sensor tag 120 is incorporated into the lower plate 115 as described above, it may also be provided as a separate unit from the lower plate 115. In this case, as shown in Figures 1 and 2, the first and second fixed electrodes 114B can be electrically connected to the first and second input terminals 120A and 120B of the capacitance sensor tag 120, respectively.

[0064] Furthermore, in this embodiment, in order to facilitate understanding of the invention, examples of using shapes such as those exemplified in Figures 1 to 3 are shown as examples of the shapes of the variable capacitor 110 and the mounting portion 111. However, the specific shapes of the variable capacitor 110 and the mounting portion 111 provided on the upper plate 112 of the variable capacitor 110 are arbitrary. For example, in addition to the shapes shown, the variable capacitor 110 and the mounting portion 111 can be configured as part or all of the shelf board of a storage shelf used for managing product inventory, etc. (Embodiment 1). In this case, the capacitance sensor tag 120 may be incorporated into the lower plate 115 as exemplified in Figure 3. Alternatively, the capacitance sensor tag 120 may be configured separately from the variable capacitor 110, and the first and second fixed electrodes 114A and 114B may be electrically connected to the first and second input terminals 120A and 120B of the capacitance sensor tag 120, respectively, and the movable electrode 113 and the second fixed electrode 114B may be electrically connected by a conductive coil spring CCS. In any configuration, the lower plate 115 is fixed to the side plate of the storage shelf, and the upper plate 112 is connected to the lower plate 115 with coil springs CS1 to CS4 in between. The variable capacitor 110 is configured such that when the object to be measured MO is placed on the placement section 111, the coil springs CS1 to CS4 elastically deform, causing the upper plate 112 to move toward the lower plate 115, and changing the distance between the movable electrode 113 and the first fixed electrode 114A. Alternatively, (Form 2) the placement section 111 can be configured in the shape of a box or basket for managing product inventory, and the variable capacitor 110 can be configured in the shape of a pallet that serves as a base for this box or basket. For example, when the variable capacitor 110 and the placement section 111 are configured in the shape of a shelf of a storage shelf as in (Form 1), the variable capacitor 110 and capacitance sensor tag 120 can be provided for each shelf that makes up the storage shelf, and a weight detection device 10 can be installed for each shelf. Then, as in the configuration examples shown in Figures 1 to 3, when the object to be measured, MO, is placed on the mounting section 111, the lower plates 115 fixed to the side panels of the storage shelf do not move.On the other hand, each upper plate 112, which is connected to the lower plate 115 by coil springs CS1 to 4, moves (sinks down) toward the corresponding lower plate 115 as the coil springs CS1 to 4 compress (elastically deform) in accordance with the weight of the object MO to be measured placed on the mounting section 111, thereby configuring the variable capacitor 110 so that the distance between electrodes between (1) the movable electrode 113 and (2) the first and second fixed electrodes 114A and 114B changes.

[0065] In general, the capacitance "C" of a parallel plate capacitor is calculated using the following equation 1.

[0066]

[0067] In Equation 1, "ε" is the dielectric constant, and in this embodiment, air is interposed between the movable electrode 113 and the first and second fixed electrodes 114A and 114B. Therefore, the dielectric constant "ε" is equal to the dielectric constant of vacuum "ε ０ = 8.85 × 10 －１２ The value is approximately equal to (F / m) (the relative permittivity is "1.0006" and approximately "1"). Also, in (Equation 1), "d" represents the distance between the movable electrode 113 and the first fixed electrode 114A that constitute the variable capacitor 110 as a parallel plate capacitor. In this embodiment, "d" is defined as a variable that changes according to the weight of the object to be measured MO placed on the mounting section 111, as shown in Figures 2(B) and (C) (specifically, a variable that changes from "x1" to "x2"). On the other hand, in (Equation 1), "S" corresponds to the area of ​​the overlapping region of the movable electrode 113 and the first fixed electrode 114A that constitute the parallel plate capacitor, and in this embodiment, it is equal to the area "S2" of the first fixed electrode 114A.

[0068] Therefore, as described above, the upper plate 112 sinks downward in proportion to the weight of the object MO placed on the mounting section 111, and as the distance between the movable electrode 113 and the first fixed electrode 114A changes, the capacitance value "C" of the variable capacitor 110, which is configured as a parallel plate capacitor, changes accordingly (see Equation 1). In this embodiment, the capacitance sensor tag 120 is configured to detect the capacitance value of the variable capacitor 110 at this time and to wirelessly transmit detection data corresponding to the detection result to the information processing device 30 via the RFID reader / writer 20. On the other hand, in this embodiment, the information processing device 30 measures the weight of the object MO placed on the mounting section 111 based on (i) the detection data acquired from the capacitance sensor tag 120 via the RFID reader / writer 20 and (ii) measurement reference data stored in the device in advance, and notifies the user of the measurement result or manages the inventory of goods placed on the mounting section 111. The measurement standards data and inventory management methods will be described in detail later.

[0069] [A3] Characteristics of the Variable Capacitor 110 In order to investigate the characteristics of the variable capacitor 110 having the above configuration, the inventors placed weights with known weights "m" in increments of "approximately 250g" from "0kg (kilograms)" to "approximately 2kg (specifically 1.998kg)" on the mounting portion 111 of the variable capacitor 110 having the above configuration, and (1) measured the average spring length of the coil springs CS1 to 4 at that time. At the same time, the inventors (2) detected and measured the capacitance value "C" of the variable capacitor 110 in each state using the capacitance sensor tag 120. As a result, the measurement results shown in Figures 4 and 5 were obtained. Figure 4 is a graph showing the measurement results of the average spring length of the coil springs CS1 to 4 when weights with known weights "m" are placed on the mounting portion 111 of the variable capacitor 110 of this embodiment. In Figure 4, (a) the horizontal axis shows the weight "m" of the weight placed on the mounting section 111, and (b) the vertical axis shows the measurement results of the average spring length of the coil springs CS1 to 4 when the weight "m" is placed on it. Also, Figure 5 shows the capacitance value of the variable capacitor 110 detected by the capacitance sensor tag 120 when a weight with a known weight "m" is placed on the mounting section 111 of the variable capacitor 110 of this embodiment (capacitance measurement value "C" described later). ｅｘｐ． This is a graph showing the measurement results (corresponding to "). In Figure 5, (a) the horizontal axis shows the weight "m" of the weight placed on the mounting part 111, and (b) the vertical axis shows the measurement result of the capacitance value of the variable capacitor 110 detected at that time.

[0070] (1) Measurement results of the average spring length of coil springs CS1 to 4 constituting the variable capacitor 110 In this experiment, a method was adopted in which the distance between FR4 of the upper plate 112 and the lower plate 115 constituting the variable capacitor 110 was measured using calipers. In the prototype used in this experiment, double-sided tape with a thickness of "100 μm" was used as a means of fixing the coil springs CS1 to 4. In addition, in the variable capacitor 110 of this embodiment, gold flash GF is applied to the movable electrode 113 provided on the upper plate 112 and the second fixed electrode 114B provided on the lower plate 115, and the conductive coil spring CCS is in contact with the gold flash GF portion (see Figures 2 and 3). The thickness of each electrode is "several tens of μm", and the thickness of the gold flash GF is "100 nm (nanometers)". For this reason, the average spring length of coil springs CS1 to 4 can be approximated by measuring the distance between FR4 of the upper plate 112 and the lower plate 115. Furthermore, subtracting "several tens of micrometers" twice from the distance measured by calipers gives the distance between the electrodes, and subtracting "100 micrometers" twice gives the average spring length of coil springs CS1 to CS4. However, the measurement accuracy of calipers is approximately "±0.05 mm" for measurements of "50 mm" or less (JIS (Japanese Industrial Standard) B7507:2016). Considering the errors during manual measurement, the influence of the thickness of electrodes 113, 114A, and 114B, the double-sided tape used as a fixing means, and the gold flash GF on the measurement results is considered to be very small and negligible. For this reason, in this experiment, the distance between the upper plate 112 and the lower plate 115 FR4 measured with calipers is used directly as the average spring length.

[0071] As shown in FIG. 4, when nine weights with different weights “m” were placed on the placement portion 111 of the variable capacitor 110 of the present embodiment, it was found that the respective plots showing the measurement results of the average spring length were arranged substantially linearly, and it was confirmed that they follow Hooke's law shown in (Equation 4) described later. When fitting using the least squares method while using the solver of Microsoft Excel (registered trademark) for the scatter diagram shown by these respective plots, a regression line (y = -2.904x + 9.419) shown by the solid line in the graph of FIG. 4 was obtained. In this regression line, the objective variable “y” corresponds to the average spring length of the coil springs CS1 to CS4, and the explanatory variable “x” corresponds to the weight “m” of the weight placed on the placement portion 111. Also, in order to examine the goodness of fit, or the degree of conformity, of the regression line to the measurement results of the average spring length of the coil springs CS1 to CS4 and the weight “m” of the weight, the coefficient of determination “R ２ ” (also called “contribution rate”). At this time, the following (Equation 2) was used to calculate the coefficient of determination.

[0072]

[0073] In (Equation 2), the average spring length (measured value or observed value) is defined as y = {y １ , y ２ , … y Ｎ} and f = {f １ , f ２ , … f Ｎ}, and the sum of the squares of the residuals is defined as a value obtained by subtracting the sum of the squares of the deviations from the average value of the measured values “y bar” from “1”. In other words, at this time, the coefficient of determination is defined as the sum of the squares of the regression variation divided by the sum of the squares of the total variation, and its value was calculated by the solver. Since the definition of this coefficient of determination itself is the same as the conventional coefficient of determination calculation formula, the details are omitted. As a result, “R ２The results obtained were "0.99902" and "0.999" (hereinafter also referred to as "triple nine") or higher, indicating that the regression line can approximate the relationship between the average spring length "y" of coil springs CS1 to CS4 and the applied weight "m" (i.e., corresponding to the explanatory variable "x" in the regression line) with very high accuracy. In addition, the slope of the first term on the right side of this regression line equation, "-2.904", is the combined spring constant "k" of the four coil springs CS1 to CS4 that constitute the variable capacitor 110. ｔｏｔａｌ (See Equation 4) and gravitational acceleration "g = 9.80665 m / s²" ２ This is a value related to the equivalent spring constant "k". ｔｏｔａｌ This can be calculated based on the slope of the first term on the right side, "-2.904", and the acceleration due to gravity (the calculation method is omitted). Furthermore, the second term on the right side of this regression line (i.e., the intercept), "9.419 mm", represents the value obtained by linear regression analysis of the average spring length of the four coil springs CS1 to CS4 when no weight is placed on the mounting part 111 (i.e., when the mounted weight is "0 kg"). The measured value of the average spring length when the mounted weight is "0 kg", which corresponds to this second term on the right side, is "9.44 mm", and it has been found that the above regression equation can obtain a value close to the measured value with high accuracy. It is thought that the reason why the measured value of the average spring length when the mounted weight "m" is "0 kg" is "9.44 mm" and the value obtained by linear regression analysis (i.e., the second term on the right side) is "9.419 mm" is as follows. (1) In the variable capacitor 110 of this embodiment, coil springs CS1 to CS4, each with an initial length (natural length) of "10 mm", are sandwiched in parallel between a fixed lower plate 115 and an upper plate 112, and both 112 and 115 are connected by the coil springs CS1 to CS4. Therefore, the four coil springs CS1 to CS4 have shortened slightly from their initial length due to the weight of the upper plate 112 on which the mounting portion 111 and movable electrode 113 are provided. (2) Due to individual differences based on manufacturing tolerances of the four coil springs CS1 to CS4, the average spring length of the coil springs CS1 to CS4 has become slightly shorter than its natural length. (3) The natural length has become slightly shorter due to "sagging" (deterioration over time) of the coil springs CS. These factors are thought to have combined to cause the average spring length to become about "0.5 mm" shorter than its initial length.

[0074] As shown in Figure 4, when the applied weight was "0 kg", the average spring length of coil springs CS1 to CS4 was "9.44 mm" as measured, and "9.419 mm" as obtained by linear regression analysis of the measurement results (for example, corresponding to "x1" in the example shown in Figure 2(B)). On the other hand, when the applied weight was approximately "2 kg" (specifically, "1.998 kg"), the measured average spring length (for example, corresponding to "x2" in the example shown in Figure 2(C)) was "3.658 mm". The average spring length obtained by linear regression analysis was "3.618 mm", confirming that the average spring length can be calculated with high accuracy using the regression equation in this case as well. Furthermore, in this experiment, the area "S2" of the first fixed electrode 114A was "0.0128 m²". ２ The variable capacitor 110 was used. Substituting the measured average spring length into the above (Equation 1) to calculate the capacitance value "C" of the variable capacitor 110, the capacitance value is "12.029 pF (picofarads)" when the placed weight is "0 kg", and the capacitance value is "31.043 pF" when it is approximately "2 kg".

[0075] In contrast, the capacitance value of the variable capacitor 110 measured by the capacitance sensor tag 120 at this time (the capacitance measurement value "C" described later) ｅｘｐ． As shown in Figure 5, the capacitance value of the variable capacitor 110 was "19.78 pF" when the applied weight "m" was "0 kg". On the other hand, when the applied weight "m" was approximately "2 kg", the capacitance value of the variable capacitor 110 was "C ｅｘｐ．The result was "42.70 pF," and comparing the calculated capacitance values ​​of the variable capacitor 110, "12.029 pF" and "31.043 pF," calculated based on the measurement results of the average spring length shown in Figure 4 above and (Equation 1), the measured value was about 1.4 to 1.7 times larger. Even when the weight "m" of the weight was changed in the series of measurements, this trend did not change significantly, and the calculated capacitance value according to (Equation 1) and the capacitance value actually measured by the capacitance sensor tag 120 were roughly by this ratio. Therefore, the inventor assumed that some factor was contributing to the discrepancy between the calculated value and the measured value, and considered the cause of the discrepancy. At this time, the inventor calculated the capacitance of the variable capacitor 110 based on (Equation 1) as "C ｃａｌｃ． ", the measured value is "C ｅｘｐ． Set it as " and calculate value "C ｃａｌｃ． The value obtained by multiplying " by a predetermined coefficient "β" is "C ｅｘｐ． Assuming that this is the case, we defined the relationship shown in equation 3 below.

[0076]

[0077] Here, since (Equation 1) does not contain information on the weight "m", it is difficult to directly calculate the applied weight "m" from (Equation 1). Therefore, the inventor calculated the capacitance measurement value "C" using the following method from the spring equilibrium equation using Hooke's Law. ｅｘｐ． This establishes the relationship with the weight "m" that is placed on the support. First, according to Hooke's Law, when the weight placed on the support section 111 is at rest, the force of gravity and the repulsive force of the spring are in equilibrium, and the following relationship (Equation 4) holds true.

[0078]

[0079] In (Equation 4), "m" is the weight of the weight placed on the mounting section 111, "g" is the acceleration due to gravity, and "k" is the acceleration due to gravity. ｔｏｔａｌ" is the combined spring constant of coil springs CS1 to CS4, and "x" is the average compression amount of coil springs CS1 to CS4 (for example, "x1 - x2" in the example shown in Figures 2(B) and (C)). Each coil spring CS1 to CS4 has a different spring constant, but in the variable capacitor 110 system of this embodiment, the four coil springs CS1 to CS4 are connected in parallel. When springs are connected in parallel, the combined spring constant "k" is the sum of the spring constants of each coil spring CS1 to CS4. ｔｏｔａｌ This is the result. Whether or not to put a minus sign on the right side of (Equation 4) is a matter of the direction of the force, etc., so for now we will adopt the equation without a minus sign on the right side of (Equation 4), and "C" in (Equation 3 ｃａｌｃ． By substituting (Equation 1) into the equation, we derived (Equation 5) below.

[0080]

[0081] Here, the electrode distance "d" between the movable electrode 113 and the first fixed electrode 114A is variable depending on the weight "m" of the counterweight. Specifically, when there is no counterweight, the initial distance "d ｉｎｉｔ． (That is, the average spring length measured when the applied weight "m" is "0 kg" is "9.44 mm"), and when a weight is placed on it, it will decrease by "x", which is the average compression amount of coil springs CS1 to CS4. This can be expressed as follows (Equation 6).

[0082]

[0083] Furthermore, from (Equation 4), the average compression amount "x" of coil springs CS1 to CS4 can be expressed as a function of the applied weight "m" as shown in (Equation 7) below.

[0084]

[0085] Furthermore, substituting (Equation 7) into (Equation 6) yields (Equation 8) below.

[0086]

[0087] In the result obtained in (Equation 8), both the numerator and denominator of the right-hand side are set to "d ｉｎｉｔ By dividing by ", equation (8) can be transformed as shown in equation (9) below.

[0088]

[0089] Here, in (Equation 9), the measured capacitance value of the variable capacitor 110 is "C". ｅｘｐ． Since the relationship between " and the applied weight "m" is shown, the inventors have adopted a method of defining parameters "A" and "B" as shown in (Equation 10) below and simplifying the relationship in (Equation 9) to (Equation 11). In this embodiment, parameters "A" and "B" correspond to, for example, the "first and second parameters" of the present invention, and (Equation 11) and its modified form (Equation 13) correspond to, for example, the "first mathematical formula" of the present invention.

[0090]

[0091]

[0092] From this (Equation 11) and the measurement results in Figure 5, the applied weight "m" and the measured capacitance value "C" of the variable capacitor 110 can be determined. ｅｘｐ． The graph is such that the axis of inverse proportion has shifted, and using this (Equation 11), the capacitance value detection result "C ｅｘｐ． It is presumed that the applied weight "m" can be calculated from this. For this reason, the inventor performed curve fitting on the scatter plot of measurement results shown in Figure 5 using a nonlinear least squares method, such as the steepest descent method, iterative method, Newton's method, Gauss-Newton method, or Levenberg-Marguart method. Note that the nonlinear least squares method is the same as conventional methods, so the details are omitted. At this time, the inventor used Microsoft Excel® solver to minimize the sum of squares of residuals (i.e., the coefficient of determination "R" calculated according to (Equation 2)). ２ The values ​​of parameters "A" and "B" were calculated to appropriately approximate the scatter plot shown by each plot in Figure 5 with the regression curve shown by (Equation 11) (so that " approaches "1"). As a result, the results "A = 20.08" and "B = 0.2663" were obtained. Note that the parameter "A" in (Equation 11) is the capacitance measurement value "C" of the variable capacitor 110 when the applied weight is "0 kg" from (Equation 10). ｅｘｐ．This parameter corresponds to "d". This parameter "A" is determined by the shape factor and the natural length of the coil springs CS1 to 4. ｉｎｔ The parameter "A" is defined by the dielectric constant "ε" and the electrode area of ​​the variable capacitor 110 as a parallel plate capacitor (in this embodiment, the area of ​​the first fixed electrode 114A) "S2". From the measurement results of the capacitance of the variable capacitor 110 using an actual device (see Figure 5), it has been found that "A = 19.78". On the other hand, the value of parameter "A" obtained by the curve fitting using (Equation 11) for the measurement results in Figure 5 is "20.08", as shown in Figure 5, and it has been found that the error with respect to the measurement results using an actual device is sufficiently small, at about 1.6%. For this reason, "20.08" obtained by this curve fitting was adopted as parameter "A". In addition, the parameter "B" in (Equation 11) is the combined spring constant "k" of the coil springs CS1 to 4, as can be seen from (Equation 10). ｔｏｔａｌ The parameter includes the acceleration due to gravity and the equivalent spring constant "k" ｔｏｔａｌ " and "d which is determined by the natural length of the coil springs CS1 to 4 ｉｎｔ It is defined by the above method, and it was found that the parameter "B" is "B = 0.2663". As a result, (1) the capacitance measurement value of the variable capacitor 110 "C ｅｘｐ． It was found that the relationship between (2) the weight "m" of the weight (i.e., the object to be measured MO) placed on the mounting section 111 and (3) the relationship (i.e., the regression curve shown by the dashed line in Figure 5) follows the relationship (i.e., Equation 11) (i.e., Equation 12) below) in the case of the actual machine used in this experiment, where parameters "A" and "B" are set to the above values.

[0093]

[0094] The capacitance measurement value "C" shown in Figure 5 ｅｘｐ． To confirm how well the above (Equation 12) fits the scatter plot obtained by plotting 9 points corresponding to the measured values ​​of the placed weight "m", the coefficient of determination "R" is calculated according to (Equation 2). ２ The result was calculated as "R ２The result obtained was "C = 0.99927", which is greater than triple nine, and the regression curve shown by (Equation 12) and the capacitance measurement value of the variable capacitor 110 "C ｅｘｐ． Based on this, it was found that the applied weight "m" can be measured with sufficient accuracy. However, this study is conditional on the coefficient "β" not changing significantly even when the weight "m" is changed, and this study showed that the capacitance measurement value "C" of the parallel plate capacitor can be measured. ｅｘｐ． From the formula, we were able to derive (Equation 11) which is used for fitting. In fact, when calculated from the results of directly measuring the compression of coil springs CS1 to CS4 (see Figure 4), the coefficient "β" does not change significantly with respect to the weight "m", and when the capacitance measurement results (see Figure 5) are applied to the fitting using (Equation 11), the coefficient of determination "R ２ Since the value approaches "1", the mathematical transformation leading to (Equation 11) is considered useful.

[0095] Based on the above considerations and experimental results, the weight measurement system 1 of this embodiment uses a formula (for example, (Equation 14)) obtained by applying the parameters "A and B" obtained by curve fitting to the following (Equation 13), which is a modified version of (Equation 11). Then, the measured capacitance value "C" of the variable capacitor 110 is used in this formula. ｅｘｐ． Based on the detection results of " and , a method was adopted to measure (calculate) the weight "m" of the object MO placed on the mounting section 111. Specifically, data corresponding to a formula (for example, (formula 14)) that applies the values ​​of parameters "A and B" obtained by fitting is stored in advance as measurement reference data in a storage unit (not shown) of the information processing device 30. The information processing device 30 then measures the capacitance measurement value "C" of the variable capacitor 110, which is indicated by the detection data acquired from the capacitance sensor tag 120. ｅｘｐ． The weight "m" of the object MO placed on the mounting section 111 is calculated by substituting this into the formula shown by the measurement reference data (for example, formula 14). For example, the capacitance measurement value "C" shown in Figure 5. ｅｘｐ．When a relationship between " and the weight "m" is obtained, the capacitance value of the variable capacitor 110 detected by the capacitance sensor tag 120 (i.e., the capacitance measurement value "C") is obtained. ｅｘｐ． Let's assume that the detection result of () is "30 pF". In this case, the information processing device 30 of this embodiment calculates that the weight "m" of the object to be measured MO placed on the mounting unit 111 is approximately "1.24 kg (kilograms)" based on (Equation 14), which is obtained by applying the parameters "A and B" obtained by fitting to (Equation 13), and the capacitance measurement value "30 pF" of the variable capacitor 110 detected by the capacitance sensor tag 120 (see Figure 5).

[0096]

[0097]

[0098] This configuration incorporates the influence of the spring constants and natural lengths of the coil springs CS1 to CS4 that constitute the variable capacitor 110 into the parameters "A and B" of (Equation 11) and (Equation 13), while also allowing the measurement of the capacitance value "C" of the variable capacitor 110 to be adjusted. ｅｘｐ． Based on this, the weight "m" of the object MO placed on the mounting section 111 can be calculated.

[0099] On the other hand, the spring constant of a spring, including a coil spring, varies depending on the wire diameter, length, material, shape, etc. Furthermore, since springs are industrial products, it is extremely difficult to manufacture springs with exactly the same characteristics even when manufactured using the same method. Ideally, it would be possible to mass-produce springs with exactly the same natural length and the same spring constant, but this is practically difficult to achieve. For this reason, even when manufacturing variable capacitors 110 to the same specifications, it becomes difficult to construct variable capacitors 110 with exactly the same initial characteristics once a different coil spring is used. As a result, the values ​​of parameters "A and B" in (Equation 11) and (Equation 13) will be different for each variable capacitor 110 that is manufactured. For this reason, when installing a weight detection device 10 including a variable capacitor 110 in a facility such as a warehouse (corresponding to the above-mentioned site), the appropriate values ​​of parameters "A and B" should be determined according to the initial characteristics of the variable capacitor 110. Then, it is necessary to generate measurement reference data corresponding to the formula obtained by applying the determined parameters "A and B" to (Equation 13) (i.e., measurement reference data suitable for the initial characteristics of the variable capacitor 110), store it in the memory unit of the information processing device 30, and make it available for use in measuring the weight of the object to be measured, MO.

[0100] Furthermore, the characteristics of the coil springs CS1 to CS4, such as their spring constant and natural length, change each time one of the following conditions (hereinafter also referred to as "characteristic change conditions") occurs, and consequently, the values ​​of parameters "A and B" in (Equation 11) and (Equation 13) also change each time. <Characteristic change condition a> When the coil springs CS1 to CS4 used in the variable capacitor 110 deteriorate over time, <Characteristic change condition b> When at least a portion of the coil springs CS1 to CS4 are replaced in order to eliminate the effects of deterioration over time, <Characteristic change condition c> When a weight exceeding the predetermined maximum weight that can be measured is applied, <Characteristic change condition d> When the weight detection device 10 is stored in the manufacturer's warehouse for a considerable period of time (for example, several months to about a year) between the time of manufacture and the start of installation and operation of the weight detection device 10, <Characteristic change condition e> When the weight detection device 10 is subjected to strong external forces or impacts during transportation or on-site installation,

[0101] Therefore, when a condition is met after the system has started operation and the characteristics of the variable capacitor 110 change, the values ​​of parameters "A and B" set in (Equation 11) and (Equation 13) are determined each time to suit the characteristics of the variable capacitor 110 of the weight detection device 10 after the characteristic change. Then, it is necessary to apply the determined parameters "A and B" to (Equation 13) to calibrate the measurement reference data. If the calibrated measurement reference data is not used, the capacitance measurement value "C" of the variable capacitor 110 will be ｅｘｐ． Based on this, it may become impossible to properly measure the weight "m" of the object MO placed on the mounting section 111. Note that the "characteristic change conditions a to e" in this embodiment correspond to, for example, the "predetermined conditions" of the present invention. However, "characteristic change conditions d and e" are conditions that correspond to the state that occurs before the weight detection device 10 is installed in a facility such as a warehouse (i.e., the installation site such as a warehouse). For this reason, if measurement reference data is generated once using the above method to match the actual characteristics, including the initial characteristics of the variable capacitor 110 of the weight detection device 10 to be installed, when the weight detection device 10 is newly installed in a facility such as a warehouse, then these "characteristic change conditions d and e" will not occur afterward and will not affect the characteristics of the coil springs CS1 to 4 or the values ​​of parameters "A and B". Accordingly, in practice, "characteristic change conditions a to c" correspond to the "predetermined conditions" of the present invention.

[0102] Here, we consider two scenarios: (a) when a weight detection device 10 including a variable capacitor 110 is newly installed in a facility, measurement reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor 110, is generated; and (b) after the system has started operation, a condition is met that satisfies any of the "characteristic change conditions a to c". In this case, the characteristics of the variable capacitor 110 or the weight detection device 10 change from one individual to another, and also change according to the characteristic change conditions that occur. Therefore, unless the values ​​of parameters "A and B" that match the characteristics of the variable capacitor 110 after the characteristic change are appropriately determined and the measurement reference data is appropriately calibrated, it will not be possible to appropriately measure the weight "m" of the object MO. At this time, it is basically necessary to measure the capacitance value of the variable capacitor 110 while finely changing the weight of the weight placed on it, similar to the method in Figure 5. Then, using this method, measurement results are obtained at multiple points (for example, 9 points in the case shown in Figure 5), and parameters "A and B" are determined by performing a calibration operation in which curve fitting using (Equation 11) is applied to these measurement results. This method allows for extremely accurate determination of the values ​​of parameters "A and B" that are suitable for the actual characteristics, including the initial characteristics, of the variable capacitor 110 that constitutes a weight detection device 10 to be newly installed in a store or other facility. By applying the determined parameters "A and B" to (Equation 13), appropriate measurement reference data suitable for the actual characteristics of the variable capacitor 110 or weight detection device 10 to be installed can be generated. Furthermore, even if a condition is met that satisfies any of the "characteristic change conditions a to c," this method allows for extremely accurate determination of the values ​​of parameters "A and B" that are suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the characteristic change. By applying these parameters "A and B" to (Equation 13), the measurement reference data can be appropriately calibrated to suit the characteristics of the variable capacitor 110 or weight detection device 10 after the characteristic change. On the other hand, performing this series of calibration operations every time a variable capacitor 110 is manufactured and newly installed in a warehouse or other facility, or performing it each time a condition that satisfies any of the above "characteristic change conditions a to c" occurs, in order to calibrate the measurement reference data, would be extremely cumbersome and impractical.

[0103] In particular, in usage scenarios where multiple weight detection devices 10 are used to centrally manage inventory of multiple types of products using an information processing device 30, a state in which any of the "characteristic change conditions a to c" is met may occur for each weight detection device 10. Therefore, each time such a state occurs, it becomes necessary to repeat the same work in order to calibrate the measurement reference data for each weight detection device 10, which may impair user convenience. To address this, in the weight measurement system 1 of this embodiment, calibration is performed using the method described below when (a) a manufactured weight detection device 10 is installed in a facility and new measurement reference data suitable for the actual characteristics of the variable capacitor 110 is generated, or when (b) a state in which any of the "characteristic change conditions a to c" is met and it becomes necessary to calibrate the already generated measurement reference data. With this configuration, the weight measurement system 1 of this embodiment can (i) generate measurement reference data suitable for the actual characteristics of the variable capacitor 110 of the newly installed weight detection device 10, or (ii) reduce the workload of calibration when calibrating the measurement reference data to match the characteristics of the variable capacitor 110 that have changed due to a condition that satisfies any of the "characteristic change conditions a to c".

[0104] [A5] Calibration Method in the Weight Measurement System 1 of This Embodiment Next, the calibration method adopted in the weight measurement system 1 of this embodiment will be explained with reference to Figure 6. Figure 6 is a diagram for explaining the calibration method adopted in the weight measurement system 1 of this embodiment. (A) shows a two-point measurement method for calibration, and (B) shows the characteristic curve of the variable capacitor 110 obtained by this method.

[0105] As shown in Figure 6(A), in the weight measurement system 1 of this embodiment, the capacitance value "C" of the variable capacitor 110 is measured in two states: (a) when the placed weight "m" is "0 kg (kilograms)" and (b) when the weight is approximately "2 kg". ｅｘｐ．The capacitance sensor tag 120 detects the capacitance value at these two points (specifically, 19.90 pF when the weight is 0 kg, and 42.13 pF when the weight is approximately 2 kg). The capacitance measurement value at these two points, "C ｅｘｐ． Using the measurement results of "", a calibration method is employed to generate measurement reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor 110 that constitutes the weight detection device 10 to be newly installed in a warehouse or other facility, or to calibrate the measurement reference data to suit the characteristics of the variable capacitor 110 after a condition occurs that satisfies any of the "characteristic change conditions a to c". Here, in the regression curve of the scatter plot shown in Figure 5, which is shown by (Equation 11), only the two parameters "A and B" change with changes in the configuration of the variable capacitor 110 or the characteristics of the coil spring CS. If there are two unknown parameters, "A and B", then in principle it is possible to determine each parameter if there are two data points on the scatter plot. In this case, the specific weight "m" of the weight placed on the mounting section 111 is arbitrary, but in the example shown in Figure 6(A), the capacitance value "C" of the variable capacitor 110 is measured at two points: (a) the state of "0 kg" (i.e., no weight placed) and (b) the state with a weight of approximately "2 kg" placed. ｅｘｐ． This shows an example of how to measure "".

[0106] Here, the parameter "A" in (Equation 11) is the capacitance measurement value "C" of the variable capacitor 110 when the applied weight is "0 kg". ｅｘｐ． This is equal to (i.e., "19.90 pF"). This is because when we substitute "m = 0" into the right-hand side of (Equation 11), the denominator of the right-hand side becomes "1", and "C ｅｘｐ． This is because it becomes "= A". Also, as mentioned above, the capacitance measurement value when the applied weight is "0 kg" is "C ｅｘｐ． " is approximately equal to the parameter "A" obtained by curve fitting based on (Equation 11), and therefore the capacitance measurement value "C" in the "0 kg" state. ｅｘｐ．Applying this directly to parameter "A" has no effect. Therefore, the value of parameter "A" can be easily determined by this two-point measurement. Furthermore, the following three cases are considered: <Case 1> A case in which the number of coil springs CS constituting the variable capacitor 110 is changed. <Case 2> A case in which coil springs with different characteristics are used, and one of the coil springs CS is used as the conductive coil spring CCS, and the movable electrode 113 and the second fixed electrode 114B are made conductive (i.e., a case in which coil springs CS1 to CS4 with different characteristics are used in the same configuration as in Figures 1 to 3). <Case 3> A case in which the characteristics of coil springs CS1 to CS4 used in the variable capacitor 110 change due to the occurrence of a condition that satisfies any of the above "characteristic change conditions a to c", and the characteristics of the variable capacitor 110 change accordingly.

[0107] In these cases, the inventors' experiments have shown that the shape of the regression curve shown in Figure 5 (i.e., the curve corresponding to (Equation 11) shown by the dashed line in Figure 5) and the mathematical formula of (Equation 11) itself do not change. Therefore, (a) when a weight detection device 10 having the same configuration as in Figures 1 to 3 is manufactured using different coil springs CS1 to 4, and the weight detection device 10 is newly installed in a facility such as a warehouse to generate measurement reference data suitable for the characteristics, or (b) when any of the above "characteristic change conditions a to c" are met, appropriate calibration can be performed in the following manner.

[0108] Specifically, two-point measurements are performed in the same manner as in Figure 6(A). Based on the results of these two-point measurements, curve fitting is performed using the nonlinear least squares method to shift the position of the regression curve shown in Figure 5 (i.e., the curve corresponding to (Equation 11)) on the graph so that it passes through these two points. This determines the values ​​of parameter "A" and parameter "B" (see Figure 6(B)). For example, the results of the two-point measurements shown in Figure 6(A) are the results of a variable capacitor 110 manufactured using the same configuration as in Figures 1 to 3, but at a different time than when the measurement results in Figure 5 were obtained, using four different coil springs CS1 to CS4 than the variable capacitor 110 for which the measurement results in Figure 5 were obtained. Therefore, when the measurement in Figure 6 was performed, the values ​​of parameters "A" and "B" in (Equation 11) changed from those obtained when the measurement results in Figure 5 were obtained. Specifically, as shown in Figure 6(B), the value of parameter "A" became "19.90" and the value of parameter "B" became "0.2641". By applying the determined parameters "A and B" to (Equation 13), which is a modified version of (Equation 11), and using the resulting measurement reference data, the capacitance value "C" of the variable capacitor 110, which is composed of different coil springs CS, can be measured at different times. ｅｘｐ． Based on this, it becomes possible to appropriately measure the applied weight "m". As a result, by adopting this calibration method and determining the values ​​of parameters "A and B" that are suitable for the characteristics of the variable capacitor 110 based on the measurement results of two points, it is possible to generate measurement reference data that is suitable for the actual characteristics, including the initial characteristics of the variable capacitor 110 that constitutes the weight detection device 10 newly installed in a facility such as a warehouse (usage site).

[0109] As described above, this method allows for the generation of appropriate measurement reference data usable for measuring weight "m" without being affected by changes in the characteristics of the variable capacitor 110 or the weight detection device 10 that occur during on-site installation of the weight detection device 10, due to differences in the initial characteristics of the variable capacitor 110 caused by individual differences in the coil springs CS1 to 4 used, or the occurrence of the above-mentioned characteristic change conditions d and e. Furthermore, even if a condition is met that satisfies any of the "characteristic change conditions a to c", the measurement reference data can be calibrated to match the characteristics of the variable capacitor 110 whose characteristics have changed due to the occurrence of the condition using the calibration method based on the two-point measurement described above, and calibrated measurement reference data (hereinafter referred to as "calibrated measurement reference data") can be generated. As a result, this method allows for the generation of calibrated measurement reference data suitable for the characteristics of the variable capacitor 110 after the characteristic change, and can be used for weight measurement. For example, the measurement reference data and calibrated measurement reference data in this embodiment correspond to the "reference data" of the present invention.

[0110] Therefore, the weight measurement system 1 of this embodiment can generate measurement reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor 110 that constitutes the newly installed weight detection device 10, using only two-point measurement. Furthermore, even if a condition is met that satisfies any of the "characteristic change conditions a to c," the measurement reference data can be appropriately calibrated to suit the characteristics of the variable capacitor 110 after the characteristic change using only the two-point measurement results, without using a large number of measurement results, and calibrated measurement reference data can be generated. As a result, the weight measurement system 1 of this embodiment can dramatically simplify the calibration process and improve user convenience. Note that (Equation 11) is optimized for a configuration using multiple coil springs CS as the elastic body, and in the configuration (configuration a) using multiple leaf springs as the elastic body (see Figures 8 and 9 described later), it has been found that the accuracy of the fitting can be further improved by using (Equation 16), described later, which is obtained by adding a predetermined coefficient to (Equation 11). This point will be described in detail in other embodiments. Furthermore, in this embodiment, in order to facilitate the measurement work when generating measurement reference data suitable for the actual characteristics of the newly installed variable capacitor 110 or weight detection device 10 and when calibrating the measurement reference data, a method is adopted in which measurement reference data is generated based on two measurement results, or the measurement reference data is calibrated to generate calibrated measurement reference data. However, the present invention is not limited to this method, and a method of performing curve fitting by the nonlinear least squares method based on two or more measurement results may also be adopted. In this case, the curve fitting method is the same as the conventional curve fitting method, so the details are omitted. Moreover, based on the results of the two-point measurement described above, measurement reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor 110 that constitutes the weight detection device 10 newly installed in a facility such as a warehouse, can be generated. Furthermore, when any of the "characteristic change conditions a to c" are met, the calculation to calibrate the measurement reference data to suit the characteristics of the variable capacitor 110 or weight detection device 10 after the characteristic change may be performed using an external PC (not shown), and the measurement reference data or calibrated measurement reference data obtained by this calculation may be transferred from this PC to the information processing device 30.However, in this embodiment, the information processing device 30 will be described as performing calculations for calibration in the following manner.

[0111] (1) When a newly manufactured weight detection device 10 is installed in a facility such as a warehouse, it is necessary to determine the values ​​of parameters "A and B" in accordance with the actual characteristics, including the initial characteristics of the variable capacitor 110 that constitutes each newly installed weight detection device 10. In addition, in this case, conditions that satisfy the above-mentioned "characteristic change conditions d and e" may occur between the manufacture of the weight detection device 10 and its installation in the warehouse, which may change the characteristics of the coil springs CS1 to CS4 and the appropriate values ​​of parameters "A and B". Therefore, in this case, unless calibration is performed once using the above method after the new installation of the weight detection device 10 to generate and use measurement reference data suitable for the actual characteristics of the variable capacitor 110 of the installed weight detection device 10, it will be difficult to properly measure the weight "m" of the object to be measured MO placed on the mounting section 111 using the weight detection device 10. For this reason, when a weight detection device 10 is newly installed in a facility such as a warehouse, the user (for example, a warehouse manager) performs two-point measurement using the above method while using the weight detection device 10.

[0112] On the other hand, the information processing device 30 obtains (a) the capacitance value "C" of the variable capacitor 110 in the state where no weight is placed on the mounting section 111 (i.e., the state of "0 kg") through the two-point measurement. ｅｘｐ． (b) The capacitance value of the variable capacitor 110 when a weight of a predetermined weight (for example, approximately "2 kg") is placed on the mounting section 111 is "C ｅｘｐ．The capacitance sensor tag 120 detects this and the corresponding detection data is acquired via the RFID reader / writer 20. The information processing device 30 then determines the values ​​of parameters "A and B" that are suitable for the actual characteristics of the variable capacitor 110 that constitutes the newly installed weight detection device 10 (specifically, the initial characteristics of the variable capacitor 110 if a state corresponding to characteristic change condition d or e has not occurred by the time of installation, or the characteristics after the occurrence of the corresponding state if it has occurred) based on the results of the two-point measurement obtained in this way and the fitting data shown in (Equation 11). Then, by applying the parameters "A and B" to (Equation 13), measurement reference data suitable for the actual characteristics of the newly installed variable capacitor 110 or weight detection device 10 is generated. The information processing device 30 stores the measurement reference data generated in this way in a storage unit (not shown) and determines the capacitance measurement value "C" of the variable capacitor 110 shown by the measurement reference data and the detection data acquired from the capacitance sensor tag 120. ｅｘｐ． Based on the above, the weight "m" of the object MO placed on the mounting section 111 is calculated. At this time, the data corresponding to (Equation 11) and (Equation 13) should be stored in advance in the storage unit of the information processing device 30 as data for fitting and generation of measurement reference data, and fitting should be performed using this data to generate measurement reference data.

[0113] (2) When periodic inspections are conducted to calibrate the measurement reference data in order to eliminate the influence of "characteristic change condition a", in this case the user shall perform two-point measurements in the same manner as in Figure 6(A) during the periodic inspection work. Meanwhile, the information processing device 30 acquires the measurement results from the capacitance sensor tag 120 and performs fitting to determine the values ​​of parameters "A and B" in (Equation 11) using the above method. The information processing device 30 then determines the values ​​of parameters "A and B" that are suitable for the characteristics of the variable capacitor 110 or weight detection device 10 that have deteriorated over time in the coil springs CS1 to 4.

[0114] The information processing device 30 then applies these determined parameter "A and B" values ​​to (Equation 13) and calibrates the measurement reference data to generate calibrated measurement reference data (hereinafter also referred to as "post-inspection calibrated measurement reference data") that is suitable for the characteristics of the variable capacitor 110 or weight detection device 10 that have deteriorated over time in the coil springs CS1 to CS4. Next, the information processing device 30 overwrites the measurement reference data that was generated when the variable capacitor 110 was newly installed and stored in the memory unit with the generated post-inspection calibrated measurement reference data. As a result, in the weight measurement system 1 of this embodiment, (1) from the time of new installation of the weight detection device 10 until the periodic inspection is performed, the measurement reference data generated when the device or system was installed and the capacitance measurement value "C" of the variable capacitor 110 are used. ｅｘｐ． Based on this, the weight "m" of the object to be measured MO placed on the mounting section 111 is measured. On the other hand, (2) after periodic inspection, the post-inspection calibrated measurement standard data generated at the time of periodic inspection and the capacitance measurement value "C" of the variable capacitor 110 are used. ｅｘｐ． Based on this, the weight "m" of the object MO placed on the mounting unit 111 is measured. Subsequently, each time a periodic inspection is performed, the post-inspection calibrated measurement reference data stored in the memory unit is overwritten and updated with new post-inspection calibrated measurement reference data obtained through the calibration process. As a result, the memory unit of the information processing device 30 always stores measurement reference data or post-inspection calibrated measurement reference data that is suitable for the current characteristics of the variable capacitor 110. The information processing device 30 then uses the measurement reference data or post-inspection calibrated measurement reference data that is sequentially overwritten in this manner, and the capacitance measurement value "C" of the variable capacitor 110. ｅｘｐ． Based on this, the weight "m" of the object MO placed on the mounting unit 111 is measured. Note that the generation of the post-inspection calibrated measurement standard data may be performed by an external PC, similar to the generation of the measurement standard data. In this case, the post-inspection calibrated measurement standard data generated by the external PC may be supplied to the information processing device 30, and the measurement standard data stored in the storage unit of the information processing device 30, or the post-inspection calibrated measurement standard data, may be overwritten and updated with the post-inspection calibrated measurement standard data for use.

[0115] (3) When at least a portion of the coil springs CS1 to CS4 are replaced, in this case, in order to eliminate the influence of "characteristic change condition b", the user shall perform two-point measurement in the same manner as in Figure 6(A) while using the variable capacitor 110 after the coil springs CS have been replaced. Meanwhile, the information processing device 30 acquires the measurement results from the capacitance sensor tag 120 and performs fitting to determine the values ​​of parameters "A and B" in (Equation 11) using the above method, thereby determining the values ​​of parameters "A and B" that are suitable for the characteristics of the variable capacitor 110 or the weight detection device 10 after the replacement.

[0116] The information processing device 30 then applies the parameters "A and B" whose values ​​were determined to (Equation 13) and generates calibrated measurement reference data suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the condition corresponding to "characteristic change condition c". The information processing device 30 then overwrites and updates (i) the measurement reference data generated at the time of installation of the device or system and stored in the memory unit, (ii) the post-inspection calibrated measurement reference data, or (iii) the post-replacement calibrated measurement reference data with the generated calibrated measurement reference data. The information processing device 30 then applies the parameters "A and B" whose values ​​were determined to (Equation 13) and generates calibrated measurement reference data (hereinafter also referred to as "post-replacement calibrated measurement reference data") while calibrating the measurement reference data to a state suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the coil spring CS has been replaced.

[0117] The information processing device 30 overwrites and updates one of the following data with the post-replacement calibrated reference data generated in this manner: (i) measurement reference data generated when the variable capacitor 110 was newly installed and stored in the memory unit; (ii) post-inspection calibrated measurement reference data; (iii) if at least some of the coil springs CS have already been replaced and post-replacement calibrated measurement reference data is stored in the memory unit of the information processing device 30, then the post-replacement calibrated measurement reference data. As a result, the memory unit of the information processing device 30 is always kept with measurement reference data or calibrated measurement reference data that is suitable for the current characteristics of the variable capacitor 110 (i.e., the characteristics of the coil springs CS1 to 4 after the characteristic change). Furthermore, the information processing device 30 (1) after the installation of the weight detection device 10 until the periodic inspection is performed, uses the measurement reference data generated when the device or system was installed and the capacitance measurement value "C" of the variable capacitor 110. ｅｘｐ． Based on the above, the weight "m" of the object to be measured MO placed on the mounting section 111 is measured. On the other hand, (2) after periodic inspection, the post-inspection calibrated measurement standard data and the capacitance measurement value "C" of the variable capacitor 110 are used. ｅｘｐ． Based on the above, the weight "m" of the object to be measured MO placed on the mounting section 111 is measured. Furthermore, (3) after replacing at least a portion of the coil spring CS, the post-replacement calibrated measurement reference data and the capacitance measurement value "C" of the variable capacitor 110 are used. ｅｘｐ． Based on this, the weight "m" of the object to be measured MO placed on the mounting section 111 is measured. The generation process of the post-replacement calibrated measurement reference data may be performed by an external PC as described above, and the generated post-replacement calibrated measurement reference data may be supplied from the external PC to the information processing device 30, and used while overwriting and updating the measurement reference data etc. stored in the storage section of the information processing device 30. The information processing device 30 then (1) after the installation of the weight detection device 10 until the periodic inspection is performed, uses the measurement reference data generated at the time of installation of the device or system and the capacitance measurement value "C" of the variable capacitor 110. ｅｘｐ． Based on the above, the weight "m" of the object to be measured MO placed on the mounting section 111 is measured. On the other hand, (2) after periodic inspection, the post-inspection calibrated measurement standard data and the capacitance measurement value "C" of the variable capacitor 110 are used.ｅｘｐ． Based on the above, the weight "m" of the object to be measured MO placed on the mounting section 111 is measured, and (3) after replacing at least a part of the coil spring CS, the post-replacement calibrated measurement reference data and the capacitance measurement value "C" of the variable capacitor 110 are used. ｅｘｐ． Based on this, the weight "m" of the object to be measured MO placed on the mounting unit 111 will be measured. The generation process for the post-replacement calibrated measurement reference data may be performed by an external PC as described above, and the generated post-replacement calibrated measurement reference data may be supplied from the external PC to the information processing device 30, where it will be used while overwriting and updating the measurement reference data stored in the information processing device 30's storage unit.

[0118] (4) If a measuring object MO with a weight "m" exceeding the specified weight limit is placed on the mounting section 111, in this case, in order to eliminate the influence of "characteristic change condition c", the user shall perform a two-point measurement similar to that shown in Figure 6(A) either (i) during periodic inspection or (ii) immediately after placing the measuring object MO, in order to generate calibrated measurement reference data suitable for the characteristics of the coil springs CS1 to CS4 that have changed when the measuring object MO was placed. Meanwhile, the information processing device 30 acquires the measurement result from the capacitance sensor tag 120 and performs fitting to determine the values ​​of parameters "A and B" in (Equation 11) using the above method, thereby determining the values ​​of parameters "A and B" that are suitable for the characteristics of the variable capacitor 110 or the weight detection device 10 after the occurrence of the relevant condition.

[0119] The information processing device 30 then applies the parameters "A and B" that determined these values ​​to (Equation 13) and calibrates the measurement reference data to a state suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the state corresponding to "characteristic change condition c," thereby generating calibrated measurement reference data. The generated calibrated measurement reference data is then used to overwrite and update (i) the measurement reference data generated at the time of installation of the device or system and stored in the memory unit, (ii) the calibrated measurement reference data after inspection, or (iii) the calibrated measurement reference data after replacement. As a result, the memory unit of the information processing device 30 is always kept with measurement reference data or calibrated measurement reference data suitable for the current characteristics of the variable capacitor 110 or weight detection device 10.

[0120] As described above, the measurement reference data or calibrated measurement reference data stored in the memory unit of the information processing device 30 is sequentially overwritten and updated with calibrated measurement reference data (including calibrated measurement reference data after inspection, calibrated measurement reference data after replacement, and calibrated measurement reference data generated when a measurement target MO exceeding the weight limit is placed on the placement unit 111; the same applies in this specification) whenever a condition is met that satisfies the conditions for changing the characteristics of the variable capacitor 110. As a result, the information processing device 30 (1) from the time of installation of the weight detection device 10 until the time of periodic inspection, has the measurement reference data generated at the time of installation of the device or system and the capacitance measurement value "C" of the variable capacitor 110. ｅｘｐ． Based on this, the weight "m" of the object to be measured MO placed on the mounting section 111 is measured. On the other hand, (2) after periodic inspection, the post-inspection calibrated measurement standard data and the capacitance measurement value "C" of the variable capacitor 110 are used. ｅｘｐ． Based on the above, the weight "m" of the object to be measured MO placed on the mounting section 111 is measured. Also, (3) after replacing at least a portion of the coil spring CS, the post-replacement calibrated measurement reference data and the capacitance measurement value "C" of the variable capacitor 110 are used. ｅｘｐ．Based on the above, the weight "m" of the object MO placed on the mounting section 111 is measured. Furthermore, even if an object MO with a weight "m" exceeding the specified weight limit is placed on the information processing device 30, thereafter, the calibrated measurement reference data obtained by the above calibration method is used to measure the weight "m" of the object MO placed on the mounting section 111. Note that the occurrence of any of the "characteristic change conditions a to c" can be determined by the user, or the information processing device 30 may be configured to automatically detect the occurrence of each condition. For example, the date and time of the reference data calibration during the previous periodic inspection and the date and time of the replacement of the coil springs CS1 to CS4 are stored in the information processing device 30. Furthermore, the information processing device 30 or an external PC may be configured to notify the user, using at least one of voice and images, that a periodic inspection or replacement should be performed and the reference data calibrated when a predetermined period has elapsed from the date and time (for example, 6 months to 2 years in the case of periodic inspection, or 5 to 10 years from the date of the previous replacement in the case of elastic member replacement), and to encourage the user to perform measurement work for calibration. In this case, the information processing device 30 may acquire detection data corresponding to the two measurement results measured based on the calibration work performed by the user from the capacitance sensor tag 120 and calibrate the reference data. In addition, the information processing device 30 may monitor the detection data to determine whether a load greater than specified has been applied, and if a capacitance value exceeding a predetermined threshold is detected, it may automatically determine that calibration is necessary and prompt the user to perform calibration work. Note that the sanitary processing of the measurement reference data and various calibrated measurement reference data as described above may be performed by an external PC and supplied to the information processing device 30.

[0121] By the method described above, the weight measurement system 1 of this embodiment always uses measurement reference data or various calibrated measurement reference data suitable for the current characteristics of the variable capacitor 110 and the capacitance value "C" of the variable capacitor 110. ｅｘｐ． Based on this, the weight "m" of the object to be measured, MO, will be measured appropriately.

[0122] [A6] Results of Verification Experiment Regarding the Appropriateness of Calibration In order to verify whether appropriate measurement reference data can be generated or whether the measurement reference data can be appropriately calibrated using the calibration method described above, the inventors conducted verification experiments using the following method. (1) First, the measurement reference data or calibrated measurement reference data obtained by substituting "A = 19.90" and "B = 0.2641" obtained by the two-point measurement and calibration work shown in Figure 6 into (Equation 13) is stored in the storage unit of the information processing device 30. (2) "One", "two", and "three" bricks of unknown weight are placed on the mounting part 111 of the variable capacitor 110, and the capacitance value of the variable capacitor 110 at that time "C ｅｘｐ． The capacitance sensor tag 120 detects this and wirelessly transmits detection data corresponding to the detection result to the information processing device 30 via the RFID reader / writer 20. (3) The information processing device 30 receives the capacitance measurement value "C" indicated by the detection data acquired from the capacitance sensor tag 120 in this way. ｅｘｐ． Based on the calibrated measurement standard data stored in the memory unit, the weight "m" of the brick placed on the placement unit 111 is measured. (4) On the other hand, in order to confirm the measurement accuracy of the brick weight measured by the above method, the weight of the same brick is weighed using an electronic scale, and the measurement accuracy of the weight "m" based on the said measurement standard data or calibrated measurement standard data is investigated by comparing the two, and it is verified whether the measurement standard data is appropriately generated by the above method or whether the measurement standard data is calibrated.

[0123] The experimental results of the verification experiment are shown in Figure 7. Figure 7 is a table showing the experimental results of this verification experiment. As shown in Figure 7, (a) when "one" brick is placed on the mounting section 111, the capacitance measurement value of the variable capacitor 110 detected by the capacitance sensor tag 120 is "C ｅｘｐ． " is "23.44 pF", the measured capacitance value "C ｅｘｐ． Based on the measurement standard data or calibrated measurement standard data, the converted weight of "one" brick was "572g (grams)". On the other hand, when this "one" brick was weighed using an electronic scale, the measured value was "554g", and the measured weight by the electronic scale and the capacitance measurement value "Cｅｘｐ． The difference between the weight of the brick measured (converted) from the calibrated measurement standard data and the measured weight was "+18g", and the error was approximately "+3.22%". (b) Also, when "two" bricks were placed on the mounting section 111, the capacitance measurement value of the variable capacitor 110 detected by the capacitance sensor tag 120 was "C ｅｘｐ． " is "28.92 pF", capacitance measurement value "C ｅｘｐ． Based on the measurement reference data or calibrated measurement reference data generated by the above method, the converted weight of "two" bricks was "1181g". On the other hand, when "two" bricks were weighed using an electronic scale, the measured value was "1140g", and the measured weight by the electronic scale and the capacitance measurement value "C ｅｘｐ． The difference between the weight of the brick measured (converted) from the measurement reference data or calibrated measurement reference data generated by the above method and the weight of the brick was "+41g", and the error was approximately "+3.60%". (c) Furthermore, when "3" bricks were placed on the mounting section 111, the capacitance measurement value of the variable capacitor 110 detected by the capacitance sensor tag 120 was "C ｅｘｐ． Based on the capacitance measurement value "Cexp." and the measurement reference data or calibrated measurement reference data generated by the above method, the converted weight of "3 bricks" was "1742g". On the other hand, when the "3 bricks" were weighed using an electronic scale, the measured value was "1718g", and the measured weight using the electronic scale and the capacitance measurement value "C ｅｘｐ．The difference between the weight of "three" bricks measured (converted) from the calibration reference data and the measured weight was "+24g". The error in this case was approximately "+1.41%", and in all cases, the error between the measurement value by the electronic scale and the weight measured by the weight measurement system 1 using the measurement reference data or calibration reference data generated by the above method was at most approximately "±3.5%", indicating that measurement results that are sufficiently practical can be obtained. In particular, in situations such as managing product inventory in facilities such as warehouses, it is sufficient to determine the number of products in stock, and it is not required to obtain strictly accurate weight measurement results. For this reason, an error of this magnitude does not cause any problems in inventory management. Accordingly, it was confirmed from the results of this experiment that the above calibration method can generate sufficiently appropriate measurement reference data or calibrate the measurement reference data.

[0124] [A7] Configuration and operation of each part of the weight measurement system 1. The capacitance sensor tag 120 measures the capacitance value "C" of the variable capacitor 110 connected to the first and second input terminals 120A and 120B. ｅｘｐ．The device incorporates an IC chip ICC that performs processing to detect "weight", and also incorporates an antenna AN for transmitting and receiving electromagnetic waves in the UHF (Ultra High Frequency) band (frequency band of approximately 300 MHz to 3 GHz), such as a dipole antenna or slot antenna, or an antenna AN for transmitting and receiving electromagnetic waves in the HF (High Frequency) band (frequency band of approximately 3 to 30 MHz) or LF band (frequency band of approximately 30 kHz to 300 kHz), such as a loop coil antenna. In this embodiment, as shown in Figure 3(B), the capacitive sensor tag 120 is built into the lower plate 115 of the variable capacitor 110, so that the variable capacitor 110 alone can function as a weight detection device 10. The capacitive sensor tag 120 built into the lower plate 115 has a configuration that generates an electromotive force based on electromagnetic waves supplied from the RFID reader / writer 20 or the magnetic field generated by the RFID reader / writer 20. The shape and arrangement of the antenna AN are arbitrary and are not limited to a symmetrical shape like the one exemplified in Figure 3; an antenna AN with a shape biased to either the left or right side may also be used. By using a symmetrical antenna AN as shown in Figure 3(B), the communication sensitivity of the capacitive sensor tag 120 can be improved, and the communication distance and speed can be improved while ensuring communication stability.

[0125] Furthermore, the capacitive sensor tag 120 uses the generated electromotive force based on the electromagnetic waves received from the RFID reader / writer 20 or the magnetic field generated by the RFID reader / writer 20 to determine the capacitance value "C" of the variable capacitor 110. ｅｘｐ． While performing processing to detect the detection result, detection data indicating the detection result is wirelessly transmitted to the RFID reader / writer 20. The specific configuration of the capacitive sensor tag 120 is the same as that of a conventional RFID tag with a capacitive sensor function (for example, Patent Document 4), so the details are omitted.

[0126] The RFID reader / writer 20 is an RFID reader / writer equipped with a wired interface such as USB (Universal Serial Bus, registered trademark) or a wireless communication interface such as Bluetooth (registered trademark) or Wi-Fi (registered trademark). For example, the RFID reader / writer 20 is fixedly installed in a predetermined location within a facility such as a warehouse where the goods to be managed are stored (a predetermined location within a distance range that allows communication with the weight detection device 10 installed within the facility such as a warehouse), or it is configured as a handheld terminal device. The RFID reader / writer 20 transmits and receives electromagnetic waves under the control of the information processing device 30, or in response to input operations by a user such as a warehouse manager. At this time, the RFID reader / writer 20 transmits and receives electromagnetic waves in one of the frequency bands of the UHF band, HF band, or LF band used to drive the capacitive sensor tag 120 and acquire detection data. With this function, the RFID reader / writer 20 drives the capacitive sensor tag 120 and simultaneously reads the capacitance value "C" of the variable capacitor 110 detected by the capacitive sensor tag 120. ｅｘｐ． The system acquires detection data corresponding to the above and supplies it to the information processing device 30. The configuration of the RFID reader / writer 20 is the same as that of a conventional passive RFID reader / writer.

[0127] The information processing device 30 is a computer system for managing the inventory status of goods stored in a warehouse, and is composed of a display (not shown), keyboard, mouse, touch panel mounted on the display, speaker, HDD (Hard Disk Drive) or SSD (Solid State Drive), or a storage unit composed of these combined with RAM (Random Access Memory). When a user such as a warehouse manager installs the device or system in a facility such as a warehouse or store, they are required to use the information processing device 30 to generate measurement reference data in the information processing device 30 or an external PC using the method described above and store it in the storage unit, and to register product attribute information indicating the attributes of the goods to be managed in inventory using the weight detection device 10. The specific content of the product attribute information is optional. For example, it is sufficient to register information that is necessary for inventory management of the product, such as the product name, GTIN (Global Trade Item Number), weight per unit (hereinafter also referred to as "unit weight"), unit price, quantity of inventory currently stored in the warehouse, and quantity of inventory requiring additional ordering (see Figure 12 below). The data corresponding to (Equation 13) used to generate the measurement standard data and the data corresponding to (Equation 11) used for fitting should be stored in the memory unit in advance. The information processing device 30 then stores the product attribute information registered by the warehouse manager in the memory unit and executes the processing necessary for inventory management of the product.

[0128] Furthermore, the information processing device 30 has an input / output interface that communicates according to the same communication protocol as the input / output interface mounted on the RFID reader / writer 20. The information processing device 30 outputs a control command to the RFID reader / writer 20 at a predetermined timing, causing the RFID reader / writer 20 to transmit and receive electromagnetic waves and acquire detection data from the capacitive sensor tag 120. Based on this detection data, the information processing device 30 measures the total weight "m" (i.e., the weight "m" of the object to be measured) of the goods (i.e., the object to be measured MO) placed on the placement unit 111. Based on the total weight "m" measured in this way, the information processing device 30 manages the inventory of the goods placed on the placement unit 111. Alternatively, the information processing device 30 may be configured to present the measurement result of the total weight "m" of the goods to a user such as a warehouse manager without performing inventory management. In this case, the measurement result in "m" of weight may be displayed on the display, or the measurement result may be announced by voice, or the measurement result may be announced by voice along with the display of the measurement result on the screen. Furthermore, if the RFID reader / writer 20 is a handheld type, when a user such as a warehouse manager receives detection data read from the capacitive sensor tag 120 by the RFID reader / writer 20, the total weight "m" of the goods placed on the placement unit 111 may be measured based on the detection data.

[0129] Here, in order to appropriately measure the weight "m" of the product inventory placed on the mounting section 111 based on the detection results, it is necessary to use measurement reference data that reflects the characteristics of the coil springs CS1 to CS4 that constitute the variable capacitor 110 at that time. In particular, as described above, the characteristics of the coil springs CS1 to CS4 and the characteristics of the variable capacitor 110 or the weight detection device 10 change when any of the above "characteristic change conditions a to e" are met. Consequently, the values ​​of parameters "A and B" in (Equation 11) and (Equation 13) change. As described above, the influence of the initial characteristic change based on "characteristic change conditions d and e" can be excluded by determining the values ​​of parameters "A and B" according to the actual characteristics of the variable capacitor 110 or the weight detection device 10 at the time of new installation of the device or system and generating measurement reference data. On the other hand, regarding characteristic changes caused by any of the "characteristic change conditions a to c," since these occur after installation, it is necessary to generate calibrated measurement reference data while determining parameters "A and B" each time during periodic inspections, etc., to match the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the relevant condition. For this reason, when a state is reached that satisfies any of the "characteristic change conditions a to c" after a new installation of the device or system in a facility such as a warehouse, the information processing device 30 determines the values ​​of parameters "A and B" suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the characteristic change using the above method (i.e., a calibration method that performs fitting using the results of two-point measurements). The information processing device 30 or an external PC then applies the determined parameter values ​​"A and B" to (Equation 13) to generate calibrated measurement reference data suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the state that satisfies the relevant characteristic change condition, and overwrites the measurement reference data generated at the time of installation of the device or system with the calibrated measurement reference data.In this case, the weight placed on the mounting section 111 may be a weight of a known weight. For example, four bottles of soft drinks or alcoholic beverages with a unit weight of 500g each (i.e., approximately 500ml each) may be placed to reach a predetermined weight (e.g., approximately 2kg). Alternatively, ten bags of retort food with a known unit weight (e.g., approximately 200g each) may be placed to create a state of 0kg (i.e., no weight placed) and a state with a predetermined weight (e.g., approximately 2kg) and perform two-point measurements to perform calibration. Furthermore, if a periodic inspection has already been performed at least once after the installation and commencement of operation of the device or system, and at least some of the coil springs CS1 to CS4 have been replaced, or if a measurement target MO with a weight exceeding the predetermined value has been placed, the measurement reference data should be calibrated at least once and stored. Even if calibrated measurement reference data is stored in the memory unit, the characteristics of the variable capacitor 110 or weight detection device 10 will change if any of the above "characteristic change conditions a to c" occur afterward. In such cases, it is necessary to generate new calibrated measurement reference data to match the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the condition, and overwrite the calibrated measurement reference data stored in the memory unit. For this reason, whenever such a condition occurs, the values ​​of parameters "A and B" suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the condition are determined using the above method, calibrated measurement reference data is generated, and the data is overwritten and updated in the memory unit. As a result, the memory unit of the information processing device 30 is always maintained with measurement reference data or calibrated measurement reference data suitable for the current characteristics of the variable capacitor 110 or weight detection device 10 stored in it.

[0130] The information processing device 30 then measures the total weight "m" of the goods stored on the placement unit 111 based on (1) measurement reference data generated when the weight detection device 10 was installed and stored in the memory unit, or (2) calibrated measurement reference data that has been calibrated to suit the characteristics of the variable capacitor 110 or the weight detection device 10 after the characteristics of the coil spring CS have changed and overwritten in the memory unit, and detection data acquired from the capacitance sensor tag 120. The information processing device 30 then executes a process for managing the inventory of the goods based on the measurement result. The specific method for managing the inventory of goods in the warehouse using the information processing device 30 is arbitrary, and for example, the following method can be adopted.

[0131] <Management Method a> This method manages the inventory quantity of products stored on the placement unit 111 based on the total weight "m" of the product (i.e., the weight "m" of the object to be measured MO) measured based on detection data and measurement standard data or calibrated measurement standard data. When this method is adopted, the number of products placed on the placement unit 111 is calculated by dividing the measured total weight "m" by the unit weight of the product included in the product attribute information, and (1) the calculated number of products may be displayed on a display or notified to the warehouse manager by voice, or (2) the inventory information indicating the inventory quantity of the product may be stored in a database for managing product inventory (hereinafter referred to as "DB") in association with the product attribute information (see Figure 14 below). For example, let's assume that the weight measured on the placement unit based on detection data is "1.5 kg" and the unit weight of the product included in the product attribute information is "300 g". In this case, the information processing device 30 calculates that the inventory quantity of the product placed on the placement unit 111 is "5 units," and (1) notifies the warehouse manager of the calculated inventory quantity of the product using at least one of voice and images, or (2) stores the calculated inventory quantity as inventory information in the DB in association with product attribute information, thereby maintaining the inventory quantity of the product in a state that the warehouse manager can later check.

[0132] At this time, it is desirable that the information processing device 30 identifies date and time information indicating the measurement date and time using a timer or the like built into the device, generates inventory history information by linking the inventory information corresponding to the calculated inventory quantity with the said date and time information, and stores it in the DB while associating it with product attribute information. It should be noted that there may be cases where a remainder occurs when the measured weight "m" is divided by the unit weight of the product. In this case, if the product is manufactured and sold in units of one (for example, home appliances), the remainder should be truncated to manage the inventory quantity. Also, for products such as those in which multiple products are packed in one box (for example, soft drinks packed in dozens or retort foods sold in boxes of multiple products), it is acceptable to manage the inventory as if a fractional amount has occurred. For example, for a boxed product containing 12 bottles of 300 ml soft drink each, with a unit weight of 3.6 kg per box, if the measured weight is 6 kg, the inventory quantity can be calculated by considering one box as inventory plus 8 bottles as fractional inventory. In this case, a program for executing this process should be stored in the memory unit beforehand, and a database containing product attribute information registered by the user should be built in the memory unit as well. The information processing device 30 should then execute the process according to the program, and sequentially add inventory information and inventory history information corresponding to the calculated inventory quantity associated with the product attribute information to the database. According to this method, the user can grasp and manage the changes in product inventory quantity (i.e., product shipping frequency, shipping quantity over a predetermined period, sales quantity, etc.). As a result, according to this method, the user can grasp the sales performance of products and the timing of incoming shipments. In this case, the method and timing by which the information processing device 30 acquires detection data from the capacitive sensor tag 120 of the weight detection device 10 should be matched to the format of the RFID reader / writer 20.For example, (a) if the RFID reader / writer 20 is permanently installed in a facility such as a warehouse, the information processing device 30 outputs a control command to the RFID reader / writer 20 at predetermined time intervals (for example, every 5 to 10 minutes), and at those time intervals, the capacitance value "C" of the variable capacitor 110 is sent to the capacitive sensor tag 120. ｅｘｐ． (b) If the RFID reader / writer 20 is a handheld type, the RFID reader / writer 20 may be configured to transmit the detection data to the information processing device 30 when the user reads the detection data from the capacitive sensor tag 120 using the RFID reader / writer 20.

[0133] <Management Method b> This method involves issuing an alert to instruct an additional order for goods when the inventory quantity of goods stored on the storage unit 111 (i.e., the inventory quantity of goods placed on the storage unit 111) falls below a predetermined threshold. When this method is adopted, a program for executing this process is stored in the memory unit in advance. In this case, the information processing device 30 determines the timing of the alert based on the inventory quantity information of goods that requires an additional order, which is included in the product attribute information registered by a user such as a warehouse manager, and issues an alert as necessary. Furthermore, in this case, the information processing device 30 determines the weight "m" threshold for issuing an alert based on the inventory quantity information of goods that requires an additional order, which is included in the product attribute information, and stores it in the memory unit. For example, consider a case where goods with a unit weight of "300g (grams)" are placed on the storage unit 111 and the inventory of those goods is stored and managed, and "30 units" is set as the inventory quantity information that requires an additional order. In this case, the information processing device 30 sets the threshold weight to "9 kg" (i.e., "300 g x 30 pieces") and stores it in the memory unit. The threshold information can be calculated when the product attribute information is registered, and the calculated value can be stored in association with the product attribute information. The information processing device 30 then, in accordance with the format of the RFID reader / writer 20, as in the case of "management method a" described above, (a) outputs a control command to the RFID reader / writer 20 at predetermined time intervals (for example, intervals of about 5 to 10 minutes) to send and receive electromagnetic waves, and the capacitance value "C" of the variable capacitor 110 at that timing is sent to the capacitance sensor tag 120. ｅｘｐ． (b) The system detects the presence of the RFID reader / writer and acquires the corresponding detection data, or (b) the system acquires detection data transmitted from the RFID reader / writer 20 in response to user operation. Based on the detection data acquired in this manner and the measurement reference data or calibrated measurement reference data, the information processing device 30 measures the total weight "m" of the product inventory placed and stored on the placement unit 111 and compares the measurement result with a threshold. As a result of this comparison, the capacitance measurement value "C ｅｘｐ．Based on the above, the information processing device 30 should issue an alert when the total weight "m" of the measured product inventory falls below a threshold. The method of issuing the alert is optional; for example, a string of text such as "The inventory of product XX has fallen below the specified number. Please order additional stock." may be displayed on the display, and the warehouse manager may be notified by voice. According to this method, (a) the total weight "m" of the products placed on the placement unit 111 is measured periodically at regular time intervals, and an alert is issued when the total weight "m" falls below a threshold, or (b) the total weight "m" of the product inventory is measured when the user reads detection data from the capacitive sensor tag 120 using the RFID reader / writer 20, and an alert is issued when it is compared with the threshold for ordering. As a result, according to this method, the loss of sales opportunities due to product shortages can be prevented, thereby facilitating sales activities and preventing a decrease in sales.

[0134] <Management method c> This method is a way to automatically place an order for a corresponding product with the manufacturer that produces the product when the inventory quantity of the product stored in a facility such as a warehouse falls below a predetermined threshold. In this case, the information processing device 30 is communicatively connected to the product order receiving and placing system managed by the product manufacturer via a network not shown in the figure. Then, when the inventory quantity of the product stored in the state of being placed on the placement unit 111 falls below a predetermined threshold, the information processing device 30 automatically performs an order placement process while specifying the GTIN, product name, and order quantity of the ordered product with respect to the product order receiving and placing system of the product manufacturer. Note that the method for determining the execution timing of the automatic order placement process is the same as the method for determining the alert issuance timing in "Management method b", and the automatic order placement process may be executed when the total weight "m" of the product inventory falls below the threshold for placing the above order. Also, the timing and method for the information processing device 30 to acquire the detection data are the same as those in the above "Management method b". Furthermore, the quantity of the product to be ordered at the time of automatic order placement may be specified in advance by a user such as a warehouse manager. According to this method, when the inventory quantity of the product stored in a facility such as a warehouse falls below a predetermined quantity, the product can be automatically ordered. As a result, according to this method, it is possible to prevent out-of-stock situations of products caused by overlooking alerts or order mistakes by users, prevent the loss of sales opportunities for products, and realize the smoothness of business activities and the prevention of a decrease in sales.

[0135] As described above, according to the weighing system 1 of the present embodiment, the weight "m" of the measurement object MO (for example, the total weight "m" of the product inventory) placed on the placement unit 111 is converted into the capacitance value "C ｅｘｐ． " of the variable capacitor 110 while the capacitance value "C ｅｘｐ．Based on this, the weight "m" of the object to be measured MO can be measured and notified to the user, and the inventory of goods stored in facilities such as warehouses can be appropriately managed and replenished. Furthermore, in the weight measurement system 1 of this embodiment, in addition to when the weight detection device 10 is installed, when any of the "characteristic change conditions a to c" are met, calibration based on two-point measurement can be performed to generate measurement reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor 110 that constitutes the weight detection device 10 newly installed in a facility such as a warehouse. Moreover, the weight measurement system 1 of this embodiment generates calibrated measurement reference data in accordance with the changes in the characteristics of the coil springs CS1 to 4 and the characteristics of the variable capacitor 110 or the weight detection device 10, and uses the generated measurement reference data or calibrated measurement reference data to generate the capacitance value "C ｅｘｐ． Weight measurement can be performed based on the above. As a result, the weight measurement system 1 of this embodiment can reliably reduce the influence on the weight measurement result due to individual differences in the manufactured variable capacitor 110, and can also reliably reduce the influence of changes in the characteristics of the variable capacitor 110 due to changes in the characteristics of the coil springs CS1 to 4, as well as the influence when at least a part of the coil springs CS1 to 4 are replaced, thereby enabling appropriate measurement of the weight of the object to be measured MO.

[0136] In this embodiment, examples a to e above were given as examples of the characteristic change conditions for the coil spring CS. However, the user may pre-set the conditions under which calibration should be performed, and perform the calibration based on the two-point measurement when those conditions are met. In this embodiment, the movable electrode 113 and the second fixed electrode 114B are electrically connected by a conductive coil spring CCS (coil spring CS3 in the case of Figure 3), and the movable electrode 113 is connected to the second input terminal 120B of the capacitance sensor tag 120. However, a configuration in which the movable electrode 113 and the second fixed electrode 114B or the second input terminal 120B are electrically connected by a conductive wire may also be used. Even in this case, calibration based on two-point measurement should be performed in the same manner as in the above embodiment to generate measurement reference data. Furthermore, similar to this embodiment, the measurement reference data can be appropriately calibrated to match the characteristics of the variable capacitor 110 after a state satisfying any of the "characteristic change conditions a to c" occurs, and used for weight measurement. In this case, to ensure good conductivity between the conductive wire and the electrode, it is desirable to (a) solder one end of the conductive wire to the area on the movable electrode 113 where gold flash GF is applied, and (b) solder the other end to the gold flash GF applied on the second fixed electrode 114B or to the second input terminal 120B. Furthermore, it is desirable to use a conductive wire with a low resistance value.

[0137] [B] Second Embodiment This embodiment is realized with the same configuration as the weight measurement system 1 of the first embodiment. Therefore, unless otherwise specified, each component shown in Figures 1 to 3 above has the same configuration as the first embodiment and realizes the same function. In the first embodiment, the information processing device 30 performed curve fitting processing based on the measurement results of two-point measurement as shown in Figure 6(A) and (Equation 11) to determine the values ​​of parameters "A and B". In the first embodiment, the determined values ​​of parameters "A and B" were applied to (Equation 11) to obtain the regression curve shown by the dashed line in Figure 6(B). In the first embodiment, the determined parameter values ​​"A and B" were applied to (Equation 13) to generate (a) measurement reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor 110 or weight detection device 10 when the device or system is newly installed, or (b) calibrated measurement reference data suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after any of the "characteristic change conditions a to c" have occurred. In contrast, the weight measurement system 1 of this embodiment employs a configuration in which calibration is performed by the following method.

[0138] [B1] Calibration method in this embodiment First, similar to the calibration method in the first embodiment, the capacitance value "C" of the variable capacitor 110 in each state: (a) when no weight is placed on the mounting part 111 (i.e., when the mounted weight is "0 kg") and (b) when a weight of a predetermined weight (for example, "approximately 2 kg") is placed. ｅｘｐ． The capacitance sensor tag 120 detects this. The capacitance detected and measured when the weight is "0 kg" is equal to parameter "A" as described above, so parameter "A" is the capacitance measurement value of the variable capacitor 110 when the weight is "0 kg". ｅｘｐ． This can be determined by (as illustrated in Figure 6, "19.90 pF"). Next, the capacitance value "C" of the variable capacitor 110 detected with a weight of "approximately 2 kg" placed on the mounting section 111 is determined. ｅｘｐ．"(When illustrated in FIG. 6, "42.13 pF") is used. However, by transforming (Equation 11), it can be transformed into an equation of B = as shown in the following (Equation 15). Note that (Equation 15) of the present embodiment corresponds to, for example, the "third mathematical formula" of the present invention.

[0139]

[0140] The right side of this (Equation 15) is such that the placed weight "m" is "about 2 kg", and the parameter "A" is the capacitance measurement value "C ｅｘｐ． " in the state where no weight is placed as described above (that is, the state of "0 kg"). On the other hand, "C ｅｘｐ． " on the right side is the capacitance measurement value obtained when the weight is "about 2 kg", so all are known quantities. Therefore, by substituting these known values into (Equation 15), the parameter "B" can be calculated. Although the calculation method is omitted here, even when the weights placed on the placement unit 111 are not "0 kg" and "about 2 kg", the parameters "A and B" can be calculated. For example, even when the weights are "1 kg" and "3 kg", although the calculation becomes complicated, the capacitance values "C ｅｘｐ．If the result is obtained, both parameters can be calculated. In this embodiment, the information processing device 30 uses the results of the two-point measurement and (Equation 15) to determine the values ​​of parameters "A and B" that are suitable for the actual characteristics, including the initial characteristics of the variable capacitor 110 or the weight detection device 10, which constitute the weight detection device 10 when the weight detection device 10 is newly installed. The information processing device 30 then generates measurement reference data suitable for the characteristics of the variable capacitor 110 and stores it in the storage unit. At this time, the information processing device 30 generates measurement reference data suitable for the actual characteristics of the variable capacitor 110 or the weight detection device 10 by applying the determined parameters "A and B" to (Equation 13). Furthermore, in this embodiment, in order to respond to cases in which any of the above "characteristic change conditions a to c" are met, the user performs the above two-point measurement when (a) during periodic inspection after the start of operation of the weight detection device 10, (b) when at least a part of the coil springs CS1 to 4 are replaced, or (c) when a product weighing more than the specified limit load is placed on the placement section 111.

[0141] Meanwhile, the information processing device 30 acquires the results of the two-point measurement from the capacitive sensor tag 120 via the RFID reader / writer 20, and uses (Equation 15) to determine the values ​​of parameters "A and B" that are suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the corresponding state. The information processing device 30 then applies (Equation 13) to generate calibrated measurement reference data suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the state. The information processing device 30 overwrites and updates the measurement reference data or calibrated measurement reference data stored in the storage unit with the calibrated measurement reference data generated in this way (for example, calibrated measurement reference data after inspection or calibrated measurement reference data after replacement, etc.). As a result, the storage unit of the information processing device 30 is always maintained with measurement reference data or calibrated measurement reference data suitable for the current characteristics of the current variable capacitor 110 or weight detection device 10. The information processing device 30, in this manner, manages the inventory of goods by measuring the total weight "m" of the goods placed on the placement unit 111 based on the measurement reference data or calibrated measurement reference data that is overwritten and updated in the storage unit as needed, and the detection data acquired from the capacitance sensor tag 120. Other aspects are the same as in the first embodiment. The data corresponding to (Equation 15) used to calculate parameter "B" can be stored in the storage unit of the information processing device 30 in advance.

[0142] With this configuration, the weight measurement system 1 of this embodiment can generate measurement reference data that matches the actual characteristics of the variable capacitor 110 or weight detection device 10 at the time of new installation, including the initial characteristics, without having to install specialized fitting software, such as Microsoft Excel (registered trademark), on the information processing device 30 or other computing devices such as PCs, and without performing regression calculations using the machine power of the information processing device 30. Furthermore, the weight measurement system 1 can calibrate the measurement reference data according to the characteristics of the variable capacitor 110 or weight detection device 10 after a condition that satisfies any of the "characteristic change conditions a to c" occurs, and generate appropriate calibrated measurement reference data. As a result, the weight measurement system 1 of this embodiment can dramatically reduce the processing load on the information processing device 30.

[0143] [C] Third Embodiment Next, a third embodiment of the weight measurement system as a physical quantity measurement system according to the present invention will be described with reference to Figures 8 to 13. This embodiment is basically implemented with the same configuration as the first embodiment, except that it uses a weight detection device 100 in which the variable capacitor 110 in the weight detection device 10 of the first embodiment is replaced with a variable capacitor 1100.

[0144] In the weight detection device 10 of the first embodiment, four coil springs CS1 to CS4 are sandwiched between the upper plate 112 and the lower plate 115, connecting both 112 and 115. An IC chip ICC and an antenna AN are incorporated into the lower plate 115, and a capacitive sensor tag 120 is built into the lower plate 115. In addition, in the weight detection device 10 of the first embodiment, the first fixed electrode 114A is connected to the first input terminal 120A of the capacitive sensor tag 120. On the other hand, one of the coil springs CS1 to CS4 (coil spring CS3 in the case shown in Figure 3) is used as a conductive coil spring CCS, and the movable electrode 113 is electrically connected to the second input terminal 120B via (1) the second fixed electrode 114B, (2) the two-layer gold flash GF, and (3) the conductive coil spring CCS, thereby constructing a variable capacitor 110 between the first and second input terminals 120A and 120B of the capacitance sensor tag 120. Furthermore, in the weight detection device 10 of the first embodiment, the capacitance value "C" of the variable capacitor 110 is measured using the capacitance sensor tag 120 built into the lower plate 115. ｅｘｐ． The system employs a configuration that detects the capacitance measurement value "C". In the first embodiment, the information processing device 30 detects the capacitance measurement value "C". ｅｘｐ． Based on the measurement standard data or calibrated measurement standard data, the total weight "m" of the goods placed on the placement unit 111 (i.e., the weight "m" of the object to be measured MO) was measured. The information processing device 30 then notified the user, such as the warehouse manager, of the measurement result, or adopted a configuration that managed the inventory of goods placed on the weight detection device 10 installed in the warehouse or other facility based on the measurement result.

[0145] In contrast, the weight detection device 100 of this embodiment employs a configuration in which, as shown in Figures 8 and 9, four Z-shaped leaf springs LS1 to 4 are sandwiched between the upper plate 112 and the lower plate 115 instead of coil springs CS1 to 4, and the upper plate 112 and the lower plate 115 are connected by the leaf springs LS1 to 4. Furthermore, the weight detection device 100 of this embodiment is configured to use one of the four leaf springs LS1 to 4 as a conductive leaf spring CLS (leaf spring LS3 in the case shown in Figure 9). In the weight detection device 100 of this embodiment, the movable electrode 113 and the second fixed electrode 114B are electrically connected by this conductive leaf spring CLS, and the movable electrode 113 is electrically connected to the second input terminal 120B of the capacitance sensor tag 120 built into the lower plate 115. Figure 8 is a system configuration diagram showing the configuration of the weight measurement system 1B of this embodiment. Figure 9 is a perspective view of the upper plate 112 and lower plate 115 constituting the variable capacitor 110 of this embodiment, as seen from the electrode mounting surfaces 112A and 115A. Figure 9(A) shows a perspective view of the upper plate 112, and (B) shows a perspective view of the lower plate 115. In addition, the same reference numerals are used in Figures 8 and 9 for components that are the same as those in Figures 1 and 3. Therefore, components that are given the same reference numerals in Figures 8 and 9 as those in Figures 1 and 3 have the same configuration as in the first embodiment and achieve the same function unless otherwise specified.

[0146] With this configuration, in the weight detection device 100 of this embodiment, as shown in Figures 8 and 9, (a) the first input terminal 120A of the capacitance sensor tag 120 built into the lower plate 115 is electrically connected to the first fixed electrode 114A. On the other hand, (b) the second input terminal 120B is electrically connected to the movable electrode 113 via (1) the second fixed electrode 114B, (2) a two-layer gold flash GF, and (3) a conductive plate spring CLS. With this configuration, in this embodiment, a variable capacitor 1100 is electrically connected between the first and second input terminals 120A and 120B of the capacitance sensor tag 120. In this embodiment, the variable capacitor 1100, which functions as part of the weight detection device 100, is constructed by placing an upper plate 112 over a lower plate 115 so that the area of ​​the movable electrode 113 coated with gold flash GF contacts a conductive plate spring CLS fixed to the gold flash GF provided on the second fixed electrode 114B of the lower plate 115, as shown in Figures 8 and 9. In this embodiment as well, the movable electrode 113 and the two gold flash GFs and conductive plate spring CLS provided on the second fixed electrode 114B are fixed by fixing means such as conductive adhesive or soldering (not shown). Furthermore, the leaf springs LS other than the conductive leaf spring CLS (leaf springs LS1, 2, and 4 as exemplified in Figure 9) are fixed to the upper plate 112 and the lower plate 115 by fixing means such as double-sided tape (not shown), and the configuration prevents the leaf springs LS1 to 4 from shifting when the object to be measured MO is placed on the mounting section 111 during system operation, as in the first embodiment.

[0147] In this embodiment, the information processing device 300 then processes the capacitance value "C" of the variable capacitor 1100 detected by the capacitance sensor tag 120. ｅｘｐ．The system acquires detection data corresponding to the above from the capacitive sensor tag 120 via the RFID reader / writer 20. Then, based on the detection data and the measurement reference data or calibrated measurement reference data stored in the memory unit, the system measures the total weight "m" of the goods stored on the placement unit 111 (i.e., the weight "m" of the measurement target MO). The information processing device 300 implements a function to manage the inventory of goods based on the measurement results obtained in this way. The configuration, functions, and inventory management method of the information processing device 300 are basically the same as those of the information processing device 30 in the first embodiment, and any of the above "management methods a to c" may be adopted. In this embodiment as well, the information processing device 300 measures the total weight "m" of the goods placed on the placement unit 111 (i.e., the weight "m" of the measurement target MO) based on the detection data and the measurement reference data or calibrated measurement reference data. Furthermore, the information processing device 300 may display the measurement result, or notify the user, such as a warehouse manager, of the measurement result of the placed weight "m" using at least one of audio and / or images.

[0148] Here, as described above, the regression curve obtained by applying the parameters "A and B" determined by curve fitting using (Equation 11) to (Equation 11) is optimized for a configuration in which, for example, four coil springs CS1 to CS4 are used, with one of the coil springs CS being used as a conductive coil spring CCS, or the movable electrode 113 and the second fixed electrode 114B or the second input terminal 120B are electrically connected by a conductive wire. On the other hand, in this embodiment, instead of coil springs CS1 to CS4, four Z-shaped leaf springs LS1 to CS4 are used, with one of the leaf springs LS being used as a conductive leaf spring CLS (in the case of Figure 9, leaf spring LS3). Therefore, due to the influence of the leaf spring CLS used for conductivity, when performing curve fitting using (Equation 11), a slight influence from using the leaf spring LS for conductivity occurs. Therefore, in this embodiment, a method is adopted to generate measurement reference data and calibrated measurement reference data while adding an additional parameter (i.e., the parameter "P" in (Equation 16)) to (Equation 11), and this point will be explained below.

[0149] [C1] Characteristics and measurement reference data of the variable capacitor 1100 Next, the characteristics and measurement reference data of the variable capacitor 1100 of this embodiment will be described using Figures 10 to 13. Figure 10 is a diagram showing the measurement results of the average spring length of the leaf springs LS1 to 4 when weights of known weights from "0 kg" to approximately "2 kg" in increments of approximately "250 g" were placed on the mounting part 111 of the variable capacitor 1100 which functions as a weight detection device 100 of this embodiment, similar to Figure 4. The horizontal axis shows the weight "m" and the vertical axis shows the average spring length. The measurement in Figure 10 employs the same method as the measurement in Figure 4, by measuring the distance between the upper plate 112 and the lower plate 115 FR4 using calipers.

[0150] As shown in Figure 10, when a weight of known weight was placed on the mounting section 111 of the variable capacitor 1100, which functions as the weight detection device 100 of this embodiment, the measurement results of the average spring lengths of the leaf springs LS1 to 4 were found to be arranged in a nearly straight line, similar to the case of the variable capacitor 110 of the first embodiment. The scatter plots shown by these plots were fitted using the least squares method with Microsoft Excel® solver. As a result, a regression line (y = -4.766x + 12.485) shown by the dashed line in the graph of Figure 10 was obtained. In this regression line, the dependent variable "y" corresponds to the average spring length of the leaf springs LS1 to 4, and the independent variable "x" corresponds to the weight "m" of the weight placed on the mounting section 111. Furthermore, in order to investigate the goodness of fit, or degree of fit, of the regression line to the measurement results of the average spring length of leaf springs LS1 to 4 and the weight "m", the coefficient of determination "R" is calculated using the above (Equation 2). ２ When asked for "R ２The result obtained was "=0.99748". Although the value of the coefficient of determination is slightly below triple nine, the regression line sufficiently approximates the relationship between the average spring length "y" of leaf springs 1 to 4 and the applied weight "m" (i.e., corresponding to the explanatory variable "x" in the regression line), and it was confirmed that the measurement results are almost linear. Therefore, it was found that the relationship (equation 4) corresponding to Hooke's Law can be sufficiently applied to the variable capacitor 1100 of this embodiment as well. In addition, the slope of the first term on the right side of the equation of this regression line, "-4.766", is the combined spring constant "k" of the four leaf springs LS1 to 4 that constitute the variable capacitor 1100, similar to the first embodiment. ｔｏｔａｌ (See Equation 4) This is a value related to gravitational acceleration. Therefore, the equivalent spring constant "k" ｔｏｔａｌ This value can be calculated based on the slope of the first term on the right-hand side, "-4.766", and the acceleration due to gravity (the calculation method is omitted). Furthermore, the second term on the right-hand side of this regression line (i.e., the intercept), "+12.485 mm", represents the value obtained by linear regression analysis of the average spring length of the four leaf springs LS1 to LS4 when no weight is placed on the mounting part 111 (i.e., when the mounted weight is "0 kg"). The measured value of the average spring length when the mounted weight is "0 kg", which corresponds to this second term on the right-hand side, is "12.205 mm", and it has been found that the above regression equation can obtain a value close to the measured value with high accuracy. It should be noted that the reason why the average spring length when the mounted weight "m" is "0 kg" is "12.205 mm" in the measured value and the value obtained by linear regression analysis (i.e., the second term on the right-hand side) is "12.485 mm" is thought to be due to a combination of the following factors. (1) In the variable capacitor 110 of this embodiment, leaf springs LS1 to 4 with an initial length (natural length) of "13.6 mm" were used. (2) The leaf springs LS1 to 4 were sandwiched in parallel between the fixed lower plate 115 and the upper plate 112, and the two plates 112 and 115 were connected by the leaf springs LS1 to 4. As a result, the four leaf springs LS1 to 4 were compressed from their initial length by the weight of the upper plate 112 on which the mounting portion 111 and the movable electrode 113 are provided. (3) As a characteristic of the leaf springs LS1 to 4 used, the leaf springs LS1 to 4 had the characteristic that their natural length changed significantly when first used.

[0151] The inventors initially believed, based on the above measurement results, that, similar to the first embodiment, it would be possible to generate measurement reference data suitable for the actual characteristics of the newly installed variable capacitor 1100 or weight detection device 100, including the initial characteristics of the variable capacitor 1100 or weight detection device 100, by curve fitting (nonlinear least squares method) based on (Equation 11). Furthermore, they assumed that even if any of the "characteristic change conditions a to c" occurred, the measurement reference data could be calibrated to suit the changed characteristics of the variable capacitor 1100 or weight detection device 100, thereby generating calibrated measurement reference data. For this reason, the capacitance value "C" of the variable capacitor 1100 was actually calculated using the same method as in Figure 5. ｅｘｐ． When we measured "", we obtained the measurement results shown in Figure 11. Figure 11(A) shows the capacitance measurement value "C" when a weight with a known weight "m" is actually placed on the mounting part 111. ｅｘｐ． This is a graph showing the measurement results. Figure 11(B) shows the relationship between the measurement results and the regression curve (shown as the dashed line in Figure 11(B)) obtained by performing curve fitting using (Equation 11).

[0152] As shown in Figure 11(B), the capacitance value "C" of the variable capacitor 1100 measured by the weight detection device 100 of this embodiment ｅｘｐ． Applying (Equation 11) to the measurement results of the weight "m" of the weight placed on the mounting section 111, and performing curve fitting using the nonlinear least squares method, the parameter "A" was determined to be "18.47" and the parameter "B" to be "0.3080". In determining the values ​​of these parameters "A and B", the coefficient of determination "R" shown by (Equation 2) was used. ２ The values ​​of parameters "A and B" were determined such that "" approaches "1". To confirm the goodness of fit of the regression curve (i.e., the dashed line in Figure 10(B)) obtained by applying the parameters "A and B" determined in this way to (Equation 11) to the measurement results (i.e., the measurement results shown in Figure 10(A)), the coefficient of determination "R" was calculated according to (Equation 2). ２ The result was calculated as "R ２The result obtained was "0.99290" and "0.99 (double nine)" or higher, but it was below the result of triple nine. The coefficient of determination "R" ２ Since the value is 0.99 or greater, it is considered that no practical problems will occur even if the measurement reference data corresponding to the regression curve obtained by performing curve fitting by (Equation 11) on the measurement result is used to measure the placed weight "m", or if the placed weight "m" is measured using calibrated measurement reference data generated by the same method after a condition satisfying any of the "characteristic change conditions a to c" occurs. However, upon closer examination of Figure 10(B), it was found that the plot at "0 kg" and the regression curve obtained by (Equation 11) are slightly misaligned. The inventors have considered how to correct this misalignment and obtain highly accurate measurement reference data or calibrated measurement reference data even in the configuration of the variable capacitor 1100 of this embodiment, and the contents and results of this consideration will be explained below.

[0153] [C2] Consideration and results for obtaining highly accurate measurement reference data or calibrated measurement reference data using the variable capacitor 1100 Next, the consideration and results will be explained with reference to Figure 12. Figure 12 shows the mounted weight "m" of the variable capacitor 1100 in this embodiment and the capacitance measurement value "C ｅｘｐ． This graph displays the regression curve (shown as the dashed line in Figure 12) obtained by performing curve fitting using the nonlinear least squares method with respect to the measurement results of the relationship between " and (shown as the scatter plot in Figure 11(A)), using the following equation (Equation 16) obtained in this study, along with the measurement results.

[0154] In this study, in order to correct the discrepancy at "0 kg" mentioned above, we decided to use the following equation (Equation 16), which is obtained by adding one parameter to equation (Equation 11).

[0155]

[0156] In (Equation 16), the first term on the right-hand side is the same as in (Equation 11), and (Equation 16) is in the form of (Equation 11) with an additional parameter "P" added to the right-hand side. Furthermore, (Equation 16) in this embodiment corresponds to, for example, the "second formula" of the present invention.

[0157] Using (Equation 16), a curve fitting was performed using the nonlinear least squares method, resulting in the values ​​of parameter "A" (10.97), parameter "B" (0.3781), and parameter "P" (8.431). In determining these parameters "A, B, and P", the coefficient of determination "R" shown in (Equation 2) was used. ２ The values ​​of parameters "A, B, and P" were determined such that "" approaches "1". To confirm the goodness of fit of the regression curve (i.e., the dashed line shown in Figure 12) obtained by applying the parameters "A, B, and P" in this way to (Equation 16) to the measurement results (i.e., the measurement results shown in the scatter plot in Figure 11(A)), the coefficient of determination "R" was calculated using (Equation 2). ２ The result was calculated as "R ２ The result was "0.99948," which is a result of triple nine or higher. This is consistent with the apparent good fit in the graph in Figure 12. The physical significance of parameter "P" has not yet been determined, but it is presumed to be a parameter determined by factors such as the parasitic capacitance due to the conductive leaf spring CLS and structural factors of the leaf spring.

[0158] Regardless of the physical significance of parameter "P", this study shows that when curve fitting is performed using the nonlinear least squares method with (Equation 16), a result of triple nine or better is obtained. Therefore, it has been found that the optimal regression curve can be obtained using this method when the variable capacitor 1100 of this embodiment is used. Furthermore, by applying the parameters "A, B, and P" determined by this method to the following (Equation 17), which is a modified version of (Equation 16), and using the measurement reference data (i.e., measurement reference data suitable for the actual characteristics including the initial characteristics of the variable capacitor 1100 or the weight detection device 100), the capacitance measurement value "C" of the variable capacitor 1100 can be obtained. ｅｘｐ．Based on this, it was found that the applied weight "m" can be measured appropriately. Furthermore, by using the calibrated measurement reference data generated by this method (i.e., calibrated measurement reference data appropriately calibrated according to the characteristics of the variable capacitor 1100 or weight detection device 100 after a state has occurred that satisfies any of the "characteristic change conditions a to c"), the capacitance measurement value "C" of the variable capacitor 1100 can be measured. ｅｘｐ． Based on this, it was found that the applied weight "m" can be measured appropriately. However, when performing calibration using (Equation 16), there are three parameters that must be identified: "A", "B", and "P". For this reason, the calibration method differs from that of the first and second embodiments, so the calibration method when using the variable capacitor 1100 of this embodiment will be described below.

[0159]

[0160] [C3] Calibration Method in this Embodiment Next, the calibration method in the weight detection device 10 using the variable capacitor 1100 of this embodiment will be explained with reference to Figure 13. Figure 13 is a diagram for explaining the calibration method adopted in the weight measurement system of this embodiment. (A) shows the three-point measurement method for calibration, and (B) shows the characteristic curve of the variable capacitor 1100 obtained by calibration. When performing calibration to appropriately determine the three parameters "A, B and P" as shown in (Equation 16), there are three unknown parameters, so at least three measurement points are required. Note that any number of measurement points is acceptable as long as there are three or more. However, in this embodiment, in order to reduce the measurement work during calibration, the capacitance value "C" when the placed weight is "0 kg" is used. ｅｘｐ．Three measurement results, including the measurement result of ", shall be used. For example, as illustrated in Figure 13(A), the capacitance value of the variable capacitor 1100 (i.e., "C") shall be measured in three states: (1) a state with no weight placed (i.e., a "0 kg" state), (2) a state with a weight of approximately "0.75 kg" placed, and (3) a state with a weight of approximately "1.5 kg" placed. ｅｘｐ． It is necessary to measure each of the following and obtain and use the measurement results for at least three points. The information processing device 300 or an external PC (not shown) then determines the parameters "A, B, and P" by performing curve fitting using the nonlinear least squares method based on (Equation 16) on these at least three measurement results. The information processing device 300 can then substitute the values ​​of the determined parameters "A, B, and P" into (Equation 17) to generate measurement reference data suitable for the initial characteristics of the variable capacitor 1100. Furthermore, by adopting this method, it is possible to create a case in which any of the above "characteristic change conditions a to c" are satisfied. However, this method requires machine power for curve fitting, similar to the case of the first embodiment. For this reason, in this embodiment, the following method of calibration based on the measurement results for three points will be used for explanation.

[0161] First, the capacitance value measured with the applied weight at "0 kg" is "C ０ (In the case of Figure 13 (A), "C ０ = 19.29 pF), the mounted weight is "m １ The capacitance value measured in the state of (for example, approximately "0.75 kg") is "C １ (In the case of Figure 13 (A), "C １ = 23.89 pF), the mounted weight is "m ２ The capacitance value measured in the state of (for example, approximately "1.5 kg") is "C ２ (In the case of Figure 13 (A), "C ２ Let it be = 34.36 pF). In this case, the parameters "A, B, and P" will be shown by (Equation 18) to (Equation 20) below, respectively. Note that (Equation 18) to (Equation 20) in this embodiment correspond to the "predetermined group of mathematical formulas" of the present invention.

[0162]

[0163]

[0164]

[0165] Since the right-hand sides of equations (18) to (20) are known, the parameters "A, B, and P" can be calculated using these formulas as "A = 12.04", "B = 0.3706", and "P = 7.253". For this reason, in this embodiment, a method is adopted in which the data corresponding to these equations (18) to (20) is stored in the memory in advance. In this embodiment, when a user such as a warehouse manager newly installs the weight detection device 100, in order to perform the above three-point measurement, (1) when no weight is placed on the placement section 111 (i.e., when the placed weight is "0 kg") and (2) when the known weight "m １ (3) The state with a weight of (e.g., "0.75 kg") placed on it, and the known weight "m ２ The capacitance value of the variable capacitor 1100 in each state, with a weight of (for example, "1.5 kg") placed on it, and in each state, "C ｅｘｐ． (That is, "C ０ , C １ and C ２ The following is measured using the information processing device 300.

[0166] At this time, the information processing device 300 receives each measured value "C" from the capacitive sensor tag 120. ０ , C １ and C ２ The detection data corresponding to the measurement value "C" is acquired, and the measured value "C" is acquired. ０ , C １ and C ２ " and the weight to which it was placed was "0 kg, m １ and m ２The values ​​of "" are substituted into (Equation 18) to (Equation 20) respectively to determine the values ​​of the parameters "A, B, and P". The information processing device 300 then applies the determined parameters "A, B, and P" to (Equation 17) to generate measurement reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor 1100 corresponding to the weight detection device 100 to be newly installed in a facility such as a warehouse, and stores it in the memory unit in advance. In addition, in this embodiment, the user performs the above three-point measurement in order to respond to cases in which any of the above "characteristic change conditions a to c" are met, such as (a) when periodic inspection is performed after the start of operation of the weight detection device 100, (b) when at least a part of the leaf springs LS1 to 4 are replaced, or (c) when a product with a weight "m" exceeding the specified weight limit is placed on the placement unit 111. The information processing device 300 then uses the three capacitance measurement values ​​"C" obtained from the measurement to determine the three capacitance measurement values ​​"C ０ , C １ and C ２ " and the load capacity "m ０ , m １ and m ２ The values ​​of and are substituted into (Equation 18) to (Equation 20), respectively. By this method, the information processing device 300 determines the values ​​of parameters "A, B, and P" that are suitable for the characteristics of the variable capacitor 1100 after the conditions have been met. The information processing device 300 then applies the determined values ​​of parameters "A, B, and P" to (Equation 17) to generate calibrated measurement reference data (for example, calibrated measurement reference data after inspection or calibrated measurement reference data after replacement) that is suitable for the characteristics of the weight detection device 100 or variable capacitor 1100 after the characteristics of the leaf springs LS1 to 4 have changed, and overwrites the measurement reference data or calibrated measurement reference data stored in the memory unit with the calibrated measurement reference data.

[0167] As a result, the storage unit of the information processing device 300 is always maintained with measurement reference data or calibrated measurement reference data suitable for the current characteristics of the variable capacitor 1100 or weight detection device 100. Based on the measurement reference data or calibrated measurement reference data that is overwritten and updated in the storage unit in this manner, and the detection data acquired from the capacitance sensor tag 120, the information processing device 300 measures the total weight "m" of the product placed on the placement unit 111 (i.e., the weight "m" of the object to be measured MO). The information processing device 300 then manages the inventory of the product based on the measurement result. The inventory management method in this case is the same as in the first embodiment, and any of the "management methods a to c" described above may be adopted. In addition to inventory management, the information processing device 300 may also display the measurement result of the placed weight "m", or notify users such as warehouse managers of the measurement result using at least one of voice and / or images. Furthermore, although not shown in the diagram, a verification experiment regarding the suitability of calibration was conducted by actually using the weight detection device 100 configured in this embodiment and performing measurements similar to those in Figure 7. As a result, the measurement error could be reduced to approximately "+1.35%" to "-0.27%" for each case of one to three bricks. Therefore, the calibration method based on three-point measurement can appropriately generate measurement reference data suitable for the actual characteristics, including the initial characteristics of the newly installed variable capacitor 1100 or weight detection device 100. In addition, it was found that the information processing device 30 can generate calibrated measurement reference data suitable for the characteristics of the variable capacitor 1100 or weight detection device 100 after the characteristic change when any of the "characteristic change conditions a to c" occur.

[0168] As explained above, according to this embodiment, even if four leaf springs LS1 to LS4 are used instead of four coil springs CS, and any of them are used as conductive leaf spring CLS, the capacitance measurement value "C" of the variable capacitor 1100 can be measured without being affected by the parasitic capacitance of the conductive leaf spring CLS. ｅｘｐ．Based on the measurement reference data or calibrated measurement reference data, the weight ("m") of the object to be measured MO placed on the mounting section 111 can be appropriately measured. Furthermore, the values ​​of the parameters "A, B, and P" can be determined simply by substituting the measurement results of three points into the pre-stored equations (Equations 18) to (Equations 20), which significantly reduces the processing load on the information processing device 30 compared to the case where curve fitting is performed using the nonlinear least squares method with (Equation 16). In this embodiment, a configuration is adopted in which the movable electrode 113 and the second fixed electrode 114B are electrically connected by a conductive leaf spring CLS (leaf spring LS3 in the case of Figure 9), and the movable electrode 113 is connected to the second input terminal 120B of the capacitance sensor tag 120. However, a configuration in which the movable electrode 113 and the second fixed electrode 114B or the second input terminal 120B are electrically connected by a conductive wire may also be used. Even in this case, calibration based on three-point measurement can be performed in the same manner as in the above embodiment to generate measurement reference data suitable for the actual characteristics of the newly installed variable capacitor 1100 or weight detection device 100. Furthermore, similar to the embodiment, the measurement reference data can be appropriately calibrated to suit the characteristics of the variable capacitor 1100 after a state satisfying any of the "characteristic change conditions a to c" occurs. In this case, in order to ensure good conductivity between the conductive wire and the electrode, it is desirable to (a) solder one end of the conductive wire to the area on the movable electrode 113 where gold flash GF is applied, and (b) solder the other end to the gold flash GF applied on the second fixed electrode 114B or to the second input terminal 120B. Also, it is desirable to use a conductive wire with a low resistance value at this time.

[0169] [D] Fourth Embodiment Next, a fourth embodiment of the weight measurement system as a physical quantity measurement system according to the present invention will be described with reference to Figures 14 and 15. Figure 14 is a diagram showing an example of data storage in the product inventory management DB stored in the storage unit of the information processing device 3000 of this embodiment, and Figure 15 is a flowchart showing the processing performed by the information processing device 3000 of this embodiment.

[0170] [D1] Overview of the Weight Measurement System of This Embodiment Here, in each of the above embodiments, a configuration was adopted in which one information processing device 30 or 300 was used to manage the inventory of one type of product that was placed and stored on the mounting section 111 of one weight detection device 10 or 100. In contrast, in the weight measurement system of this embodiment, one information processing device 3000 is used to manage multiple weight detection devices 10 or 100, and a configuration is adopted in which one information processing device 3000 manages the inventory of multiple types of products. In order to realize this function, this embodiment employs the following general method. Note that this embodiment is the same as the above embodiments except that the number of weight detection devices 10 or 100 managed by the information processing device 3000 is greater than that of the weight measurement systems 1 and 1B of each of the above embodiments, so the system configuration and the configuration of the weight detection device 10 are not shown or described.

[0171] (1) First, a weight detection device 10 or 100 is installed on each of the multiple shelves that make up a storage rack installed in a facility such as a warehouse, or multiple pallets equipped with weight detection devices 10 or 100 are installed in each of the facilities such as a warehouse. (2) The products to be placed and stored on each shelf or pallet are predetermined. (3) Users such as warehouse managers store and manage the inventory of the corresponding products using the predetermined shelves or pallets. (4) A device ID, such as a serial number, is predetermined for each of the multiple weight detection devices 10 or 100 managed by the information processing device 3000. Furthermore, this device ID is stored in advance in a memory (not shown) built into the IC chip ICC of the capacitive sensor tag 120 that makes up the corresponding weight detection device 10 or 100. Note that the device ID in this embodiment corresponds to, for example, the "identification information" of the present invention. In this case, the capacitance sensor tag 120 may be configured to incorporate the IC chip ICC and antenna AN into a part of the lower plate 115 and be built into the variable capacitor 110 or 1100, as in the above embodiments, or it may be configured as a separate unit, as in the above embodiments.

[0172] (5) Furthermore, the information processing device 3000 is provided with a product inventory management DB for product inventory management as illustrated in Figure 14. Specifically, as shown in Figure 14, (a) the following data storage fields are provided in association with a field for storing the device ID assigned to each weight detection device 10 or 100 managed by the information processing device 3000, and the product inventory management DB in which the necessary data is stored in each field is pre-stored in the storage unit of the information processing device 3000. Note that the information processing device 3000 is provided with a DB in the product inventory management DB that is associated with each device ID. (b) A field for storing measurement reference data or calibrated measurement reference data corresponding to the weight detection device 10 or 100; (c) A field for storing product attribute information of products placed on the mounting section 111 of the weight detection device 10 or 100 for inventory management; (d) A field for storing inventory information indicating the inventory quantity of the product; (e) A field for storing inventory history information of the product. A product inventory management DB containing the necessary data for each field is pre-stored in the storage unit of the information processing device 3000. The measurement reference data or calibrated measurement reference data to be stored in the field associated with each device ID in the product inventory management DB may be generated in advance by the information processing device 3000 or an external PC or other computing device using the same method as in the first to third embodiments, according to the characteristics of the weight detection device 10 or 100, and stored in the corresponding field. For example, in the case shown in Figure 14, data named "MRD001" is stored as the measurement reference data or calibrated measurement reference data for the weight detection device 10 or 100 identified by the device ID "WDD01". The weight detection device 10 or 100 stores and manages inventory of a product identified by product attribute information where the GTIN is "JAN001", the product name is "○○ Beer", the unit weight is "2100g per pack, 350g per bottle", the price information is "1200 yen per pack, 200 yen per bottle", and the inventory quantity requiring additional ordering is "10 packs". Currently, "30 packs" of this product are placed and stored in the storage unit 111, and the data storage example shows that inventory history information named "IHI001" is stored.Similarly, for other weight detection devices 10 or 100, product attribute information, inventory information, and inventory history information of products managed using the weight detection device 10 or 100 are stored in association with the device ID, measurement standard data, or calibrated measurement standard data corresponding to the weight detection device 10 or 100. Furthermore, the measurement standard data or calibrated measurement standard data stored in this product inventory management DB is calibrated each time a condition satisfying "characteristic change conditions a to c" occurs in the corresponding weight detection device 10 or 100 using the same calibration method as in the first to third embodiments, and the corresponding field is overwritten and updated with the calibrated measurement standard data generated as needed, thereby maintaining a state in which measurement standard data or calibrated measurement standard data appropriate to the current state of the corresponding weight detection device 10 or 100 is always stored. Moreover, in this embodiment, the product inventory management DB provided in the storage unit of the information processing device 3000 constitutes, for example, the "storage means" of the present invention.

[0173] [D2] As shown in the operation diagram 15 of the information processing device 3000 of this embodiment, in this embodiment, the information processing device 3000 first acquires detection data from each weight detection device 10 or 100 installed in the warehouse (step S1). The acquisition method at this time is the same as in the first embodiment and can be changed according to the configuration of the RFID reader / writer 20. For example, (a) if the RFID reader / writer 20 is a fixed installation type, control commands can be periodically output to the RFID reader / writer 20 to send and receive electromagnetic waves, thereby acquiring detection data in bulk from the capacitive sensor tags 120 of each weight detection device 10 in association with the device ID. Also, (b) if a handheld RFID reader / writer 20 is used, the RFID reader / writer 20 can send and receive electromagnetic waves in response to the operation of a user such as a warehouse manager, and read the detection data in bulk from the capacitive sensor tags 120 of each weight detection device 10 in association with the device ID. The RFID reader / writer 20 may also transmit the read detection data to the information processing device 3000, so that the RFID reader / writer 20 reads the detection data individually from the capacitive sensor tag 120 of each weight detection device 10 while associating it with the device ID. Then, the RFID reader / writer 20 transmits the read detection data to the information processing device 3000 while associating it with the device ID.

[0174] Meanwhile, when the information processing device 3000 acquires detection data associated with the device ID from the capacitance sensor tag 120 of each weight detection device 10 or 100 in this manner, it measures the total weight "m" of the stored goods placed on the placement unit 111 for each weight detection device 10 or 100 based on the detection data (step S2). At this time, the information processing device 3000 searches the product inventory management DB based on the device ID associated with the detection data acquired from the capacitance sensor tag 120 of each weight detection device 10 or 100 and reads the measurement reference data or calibrated measurement reference data corresponding to the weight detection device 10 or 100 from which the detection data was acquired. Then, the information processing device 3000 calculates the capacitance measurement value "C" of the variable capacitor 110 or 1100 indicated by the detection data corresponding to the read measurement reference data or calibrated measurement reference data. ｅｘｐ． Based on this, the total weight "m" of the products placed on the mounting section 111 of each weight detection device 10 or 100 is measured for each weight detection device 10 or 100 (step S2).

[0175] In this way, once the measurement of the total weight "m" of the products placed on the placement section 111 of each weight detection device 10 or 100 is complete, the information processing device 3000 executes an inventory management DB update process (step S3) and terminates the process. At this time, the information processing device 3000 reads the product attribute information stored in the inventory management DB in association with the device ID of each weight detection device 10 or 100, divides the measured weight "m" of the product by the unit weight to calculate the inventory quantity of the corresponding product, and stores it in the inventory information storage field of the inventory management DB. At this time, the information processing device 3000 also identifies the current date and time using a timer (not shown) built into the device, generates inventory history information by associating the current date and time with the calculated inventory quantity, and stores it in the inventory history information storage field. Note that this process is executed for each weight detection device 10 or 100 and is basically the same as "management method a" in the first embodiment, except that it is stored in the corresponding field. In this embodiment as well, the same method as "management method b or c" described above can be adopted. In this case, the information processing device 3000 calculates a threshold for the total weight "m" of goods requiring an additional order for each product whose inventory is stored and managed by each weight detection device 10 or 100, based on the inventory quantity, the quantity of additional inventory required included in the product attribute information, and the unit weight. The information processing device 3000 then compares the calculated threshold with the measured total weight "m" of the goods, and when the total weight "m" falls below the threshold (i.e., when the inventory quantity falls below the quantity required for an additional order), it issues an alert or executes a process to automatically place an order with the producer's order management system for the relevant product.

[0176] The information processing device 3000 repeats the process at predetermined time intervals (for example, every 5 to 10 minutes), or it executes the process when a user reads detection data from the capacitive sensor tag 120 using a handheld RFID reader / writer 20 and the detection data is transmitted to the information processing device 3000.

[0177] As a result, the inventory management DB is sequentially overwritten with information on the inventory quantity of each product whose inventory is being managed by each weight detection device 10 or 100, so that the current inventory quantity of each product whose inventory is being managed by each weight detection device 10 or 100 is always reflected. It is desirable that the inventory history information storage field in the inventory management DB be updated each time the above process is executed, creating additional fields and storing the inventory history information. Furthermore, even when adopting the configuration of each of the above embodiments, it is desirable to build a DB with data storage fields similar to those in Figure 14 in the storage unit of the information processing device 30 or 300 to manage the data. In addition, it is desirable that the information processing device 3000 have a function to analyze the increase or decrease in product inventory (sales, shipping and receiving status, etc.) based on the inventory history information stored in the inventory management DB and present it to the user. Furthermore, by including fractional inventory in the inventory information, more detailed inventory management can be achieved.

[0178] As described above, according to the configuration of this embodiment, multiple weight detection devices 10 or 100 installed in a facility such as a warehouse can manage and store different product inventory, while a single information processing device 3000 can centrally manage multiple weight detection devices 10 or 100. As a result, since the inventory status of multiple types of products can be centrally managed by a single information processing device 3000, the initial cost of system construction can be reduced. In addition, users such as warehouse managers can centrally manage and understand the inventory status of multiple types of products stored and managed in facilities such as warehouses and stores, dramatically reducing the workload during inventory management. Furthermore, since the measurement reference data or calibrated measurement reference data corresponding to each weight detection device 10 or 100 can be generated based on two or three measurement results, as in the above embodiments, the measurement work when generating measurement reference data suitable for newly installed weight detection devices 10 or 100, or when calibrating the measurement reference data when any of the "characteristic change conditions a to c" occur can be simplified, dramatically reducing the burden on the user.

[0179] [E] Modified Example [E1] Modified Example 1 In each of the above embodiments, a configuration was adopted in which passive capacitive sensor tags 120 and RFID reader / writer 20 were used. However, a configuration in which an active or semi-active drive method is adopted by mounting a power supply on the capacitive sensor tag 120 may also be adopted. In this case, an IC chip and antenna that realize the same functions as a normal capacitance tester are mounted inside the capacitive sensor tag 120, and the capacitance value "C" of the variable capacitor 110 or 1100 is measured using the built-in power supply. ｅｘｐ． The configuration should be such that it detects "". With this configuration, a longer communication range (for example, several tens of meters) can be secured compared to when a passive drive method is used. As a result, with this configuration, even when the weight detection device 10 or 100 and the RFID reader / writer 20 are installed at a distance from each other in a facility such as a large warehouse, store, or exhibition hall, the total weight "m" of the goods placed on the mounting section 111 of the weight detection device 10 or 100 (the weight "m" of the object to be measured MO) can be reliably measured by the information processing device 30, 300, or 3000, and product inventory can be managed.

[0180] Furthermore, even when using a handheld RFID reader / writer 20, while ensuring a long communication distance, the capacitance value "C" of the variable capacitor 110 or 1100 can be measured from a location far from the installation location of the weight detection device 10 or 100. ｅｘｐ．The detection result can be read and reliably supplied to the information processing device 30, 300, or 3000, allowing for easy measurement of the total weight "m" of the goods placed on each weight detection device 10 or 100 from a distance, thereby enabling inventory management of the goods. As a result, this modified version improves the flexibility of system installation, allows for remote measurement of the total weight "m" of goods placed on the placement section 111 in various locations, and improves convenience for users such as warehouse managers. In this case, it is necessary to change the communication method of the RFID reader / writer 20 to match the driving method of the capacitive sensor tag 120, which is the same as in conventional RFID systems. Also, the method of detecting capacitance using a power-supplied RFID is the same as in conventional capacitance testers, so the details are omitted. Furthermore, in this case, when installing the weight detection device 10 or 100 in a very low-temperature environment such as a cold storage warehouse, the inventory of goods in the cold storage warehouse can be reliably managed by using a low-temperature operating power supply such as a relatively high-performance lithium polymer battery. In this case as well, the capacitive sensor tag 120 including the power supply may be incorporated into the lower plate 115.

[0181] [E2] Modification 2 In each of the above embodiments, four coil springs CS1 to 4 or leaf springs LS1 to 4 having similar initial lengths and spring constants are provided at the four corners of the upper plate 112 and the lower plate 115, and the upper plate 112 and the lower plate 115 are connected by the coil springs CS1 to 4 or leaf springs LS1 to 4. However, in addition to the coil springs CS1 to 4 or leaf springs LS1 to 4 provided at the four corners, one additional coil spring CS or leaf spring LS having the same initial length as the other springs may be added near the center of the upper plate 112 and the lower plate 115, so that five coil springs CS or leaf springs LS are provided between the upper plate 112 and the lower plate 115, and the two plates 112 and 115 are connected by five springs. In this case, (configuration a) only the additional coil spring CS or leaf spring LS may have a different spring constant than the other coil springs CS or leaf springs LS. Furthermore, (configuration b) all five coil springs CS or leaf springs LS, including the additional coil spring CS or leaf spring LS, may have the same spring constant. By adopting "configuration a," only the coil spring CS or leaf spring LS added to the central part can have its natural frequency changed. As a result, the inventors' experiments have shown that it is possible to prevent resonance from occurring and the upper plate 112 from vibrating when the object to be measured MO is placed on the mounting part 111. Similarly, the inventors' experiments have shown that vibration of the upper plate 112 during measurement can also be prevented when "configuration b" is adopted. Therefore, according to this modification, vibration of the upper plate 112 can be prevented regardless of whether configuration a or b is adopted, thereby improving the measurement accuracy during weight measurement. In this case, when a coil spring CS is used as the elastic member, for example, measurements may be taken at two points, "0 kg" and "approximately 2 kg," as illustrated in Figure 16, and calibration based on the two-point measurements may be performed using the same method as in the second embodiment to generate measurement reference data suitable for the actual characteristics, including the initial characteristics of the newly installed variable capacitor 110 or weight detection device 10. Furthermore, if any of the "characteristic change conditions a to c" occur after the installation of the variable capacitor 110, calibrated measurement reference data suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of the condition may be generated.For example, in the case of a prototype manufactured with the configuration of this modified example, as illustrated in Figure 16, when the mounted weight "m" is "0 kg", the capacitance measurement value "C" is obtained. ｅｘｐ．When the value of the variable capacitor was "19.89 pF" (i.e., "A = 19.89") and the weight was approximately "2 kg", the value of the parameter "B" was "34.42". Substituting the results of these two-point measurements into (Equation 15) using the method of the second embodiment, the value of parameter "B" obtained was "0.2104". Note that the measurement in Figure 16 used a prototype machine with a configuration using five coil springs CS with the same initial length and spring constant. When adopting the configuration of this modified example, the values ​​of parameters "A and B" obtained in this way are substituted into (Equation 13) to generate measurement reference data suitable for the actual characteristics, including the initial characteristics of the newly installed variable capacitor 110 or weight detection device 10. Furthermore, if a state satisfying any of the "characteristic change conditions a to c" occurs after the installation of the variable capacitor 110, calibrated measurement reference data suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after the occurrence of that state should be generated. Note that, as in the first embodiment, curve fitting based on (Equation 11) is performed using the results of the two-point measurements. Then, parameters "A and B" suitable for the actual characteristics, including the initial characteristics of the newly installed variable capacitor 110 or weight detection device 10, are determined, or parameters "A and B" suitable for the characteristics of the variable capacitor 110 or weight detection device 10 after a state has occurred that satisfies any of the "characteristic change conditions a to c" are determined. If this method is adopted, the values ​​of the determined parameters "A and B" are substituted into (Equation 13) to generate the measurement reference data and calibrated measurement reference data, similar to the case where the method of the second embodiment is adopted. However, if five leaf springs LS are used instead of five coil springs, three-point measurement is performed, unlike when coil springs CS are used. Then, the information processing device 300 or 3000 determines the values ​​of parameters "A, B and P" respectively using the same method as in the third embodiment (i.e., curve fitting based on (Equation 16), or calculations based on (Equations 18) to (Equations 20)). Then, the determined value is substituted into (Equation 17) to generate measurement reference data suitable for the actual characteristics, including the initial characteristics of the newly installed variable capacitor 1100 or weight detection device 100.Furthermore, if a condition satisfying "characteristic change conditions a to c" occurs, it is necessary to generate calibrated measurement reference data suitable for the characteristics of the variable capacitor 1100 or weight detection device 100 after the occurrence of the condition, and to measure the total weight "m" of the product using the generated measurement reference data or calibrated measurement reference data. Note that other points are the same as in the first to third embodiments described above, so the details are omitted. However, when adopting a configuration in which one coil spring CS or leaf spring LS is added to the center of the upper plate 112 and lower plate 115 as in this modified example, it is necessary to prevent the movable electrode 113 and the first fixed electrode 114A from becoming electrically connected by the coil spring or leaf spring added to the center. Therefore, in the area where the spring is installed, it is necessary to either insulate the spring from both electrodes by not forming the movable electrode 113 and the first fixed electrode 114A, or to provide an insulating layer in the area where the spring contacts both electrodes 113 and 114A to prevent electrical contact between the two electrodes 113 and 114A.

[0182] [E3] Modification 3 In the above embodiments and modifications, an example was described in which a capacitance sensor tag 120 as an RFID is used as the capacitance sensor. However, instead of the capacitance sensor tag 120 as an RFID, the capacitance sensor may be configured using a capacitance tester equipped with an IC chip that communicates according to a communication protocol such as Bluetooth® or Wi-Fi®, an antenna, and a power supply. In this case, the capacitance sensor is the capacitance value "C" of the variable capacitor 110 or 1100. ｅｘｐ． The system can be configured to detect the presence of a certain value and for the information processing device 30, 300, or 3000 to wirelessly acquire detection data corresponding to the detection result from the capacitance sensor. Other aspects are the same as in the above embodiments.

[0183] [E4] Modification 4 In each of the above embodiments, a mounting portion 111 is provided on the upper plate 112 of the variable capacitor 110 or 1100, and the capacitance measurement value "C ｅｘｐ．Based on the above, the total weight "m" of the product placed on the mounting section 111 (i.e., the weight "m" of the object to be measured) was measured as an example. However, a configuration may be adopted in which a variable capacitor 110 or 1100 is used as a pressure sensor to measure the pressure applied to the upper plate 112, the measurement result is notified to the user, or historical information of the measurement result is generated based on the measurement result to monitor the change in the applied pressure.

[0184] In this case, while applying a known pressure to the upper plate 112 in advance, the capacitance value "C" of the variable capacitor 110 or 1100 at that time is determined. ｅｘｐ． The capacitance value "C" of the variable capacitor 110 or 1100, as indicated by the detection data acquired from the capacitance sensor tag 120, is measured by the capacitance sensor tag 120, and based on the measurement result, measurement reference data or calibrated measurement reference data is generated in the same manner as in each of the embodiments described above and stored in the information processing device 30 or 300 in advance. The information processing device 30 or 300 then uses the detection data acquired from the capacitance sensor tag 120 to determine the capacitance value "C" of the variable capacitor 110 or 1100. ｅｘｐ． The device can then measure the pressure applied to the upper plate 112 based on measurement reference data stored in the device or calibrated measurement reference data. The measurement method in this case is the same as in each of the embodiments described above. In this case, the IC chip ICC and antenna AN may be incorporated into the lower plate 115, and the capacitance sensor tag 120 may be built into the lower plate 115.

[0185] Furthermore, in this case, pressure detection devices (corresponding to the weight detection device 10 in each of the above embodiments) consisting of a variable capacitor 110 or 1100 as a pressure sensor and a capacitance sensor tag 120 may be installed in multiple locations, and the pressure value applied to the upper plate 112 may be measured for each pressure detection device. In this case, similar to the fourth embodiment, a device ID for identifying the pressure detection device is stored in advance on the capacitance sensor tag 120 of each pressure detection device. Also, in this case, the information processing device is configured to store measurement reference data or calibrated measurement reference data corresponding to each pressure detection device in association with the device ID, similar to the information processing device 3000 of the fourth embodiment. The capacitance sensor tag 120 generates an electromotive force based on electromagnetic waves received from the RFID reader / writer 20 or the magnetic field generated by the RFID reader / writer 20, and uses this electromotive force to measure the capacitance value "C" of the variable capacitor 110 or 1100 connected to the device. ｅｘｐ． The system detects the presence of a capacitive sensor tag 120, which then wirelessly transmits the corresponding detection data and the device ID corresponding to the device to the information processing device 30.

[0186] On the other hand, in this case, the information processing device stores measurement reference data or calibrated measurement reference data corresponding to each pressure detection device in association with the corresponding device ID, similar to the information processing device 3000 of the fourth embodiment. The information processing device then identifies the measurement reference data or calibrated measurement reference data corresponding to the relevant pressure detection device based on the device ID acquired wirelessly in association with the detection data. The information processing device then measures the pressure value applied to the upper plate 112 of the variable capacitor 110 or 1100 that constitutes each pressure detection device based on the identified measurement reference data or calibrated measurement reference data and the acquired detection data, and notifies the user of the measurement result, or generates measurement history information for each pressure detection device based on the measurement result for each pressure detection device. The information processing device is configured to monitor the change in the pressure value applied to the upper plate 112 of the variable capacitor 110 or 1100 of each pressure detection device. Other points are the same as in the fourth embodiment, so the explanation is omitted. In this modified example, the number of coil springs CS or leaf springs LS provided between the upper plate 112 and the lower plate 115 is arbitrary. The configuration in this case is the same as in the above-described embodiments and modifications.

[0187] [E5] Modification 5 In the above embodiment, the antenna AN and IC chip ICC of the capacitance sensor tag 120 were incorporated into the lower plate 115, thereby embedding the capacitance sensor tag 120 in the lower plate 115. This describes an example of a configuration in which the variable capacitor 110 and the capacitance sensor tag 120 are integrated, and the variable capacitor 110 alone functions as a weight detection device 10. However, the antenna AN and IC chip ICC of the capacitance sensor tag 120 may be embedded in the upper plate 112 side instead of the lower plate 115 side, so that the variable capacitor alone functions as a weight detection device. When this method is adopted, the configuration of the electrodes and the connection method of the electrodes to the first and second input terminals 120A and 120B of the capacitance sensor tag 120 will be slightly changed from the configuration of each of the above embodiments, so this point will be explained below.

[0188] (1) Configuration of the Weight Detection Device 1000 in this Modified Example Here, the configuration of the weight detection device 1000 and the variable capacitor 11000 in this modified example will be explained with reference to Figure 17. Figure 17 is a perspective view of the upper plate 1120 and lower plate 1150 of the weight detection device 1000 or the variable capacitor 11000 that functions as the weight detection device 1000 in this modified example, with (A) being a perspective view of the lower plate 1150 and (B) being a perspective view of the upper plate 1120.

[0189] As shown in Figure 17(A), in the variable capacitor 11000 that functions as a weight detection device 1000 in this modified example, the electrode mounting surface 1150A of the lower plate 1150 differs from the lower plate 115 in the variable capacitor 110 or 1100 of the above embodiments in that only one fixed electrode 1140 is provided on it, instead of two fixed electrodes (i.e., first and second fixed electrodes 114A and 114B). The area of ​​this fixed electrode 1140 is set to approximately "S1", similar to the movable electrode 113 provided on the upper plate 112 in the variable capacitor 110 or 1100 of the above embodiments. Furthermore, as shown in Figure 17(A), a gold flash GF is provided in a part of the area of ​​this fixed electrode 1140, and the lower plate 1150 as a whole has the same configuration as the movable electrode 113 provided on the upper plate 112 shown in Figures 3(A) and 9(A), but with the fixed electrode 1140 replaced. In other words, in this modified example, the lower plate 1150 is configured to use the movable electrode 113 of the upper plate 112 in the variable capacitor 110 or 1100 of the above embodiments as a fixed electrode 1140. Except for this point, it basically has the same configuration as the upper plate 112 in the variable capacitor 110 or 1100 of the above embodiments. In Figure 17(A), similar to Figure 3(A), a region for applying gold flash GF is provided at a position slightly away from the fixed electrode 1140 in order to align with the position of the second movable electrode 1130B, which will be described later. However, it is preferable that the area of ​​this region is not included in the area "S1", similar to the case of the movable electrode 113.

[0190] On the other hand, as shown in Figure 17(B), in the variable capacitor 11000 of this modified example, the electrode mounting surface 1120A of the upper plate 1120 is provided with two movable electrodes, first and second movable electrodes 1130A and 1130B, instead of one movable electrode 113 as in the upper plate 112 of the variable capacitor 110 or 1100 of the above embodiments. Here, (1) the first movable electrode 1130A has an area of ​​approximately "S2", similar to the first fixed electrode 114A in the above embodiments, and is provided in a region including the vicinity of the center of the upper plate 1120. (2) On the other hand, the second movable electrode 1130B has an area of ​​approximately "S3", similar to the second fixed electrode 114B in the above embodiments, and is provided on the electrode mounting surface 1120A in a state of being electrically insulated from the first movable electrode 1130A. Furthermore, a gold flash GF is formed on the second movable electrode 1130B, similar to the second fixed electrode 114B in the variable capacitor 110 or 1100 of each of the above embodiments. The first and second movable electrodes 1130A and 1130B are electrically connected to the first and second input terminals 120B of the capacitance sensor tag 120 built into the upper plate 1120, respectively.

[0191] As a result, the upper plate 1120 in the variable capacitor 11000 of this modified example has the same configuration as the lower plate 1130A in the variable capacitor 110 or 1100 of the above embodiments, in which (i) the first fixed electrode 114A of the lower plate 115 is changed to the first movable electrode 1130A, and (ii) the second fixed electrode 114B is changed to the second movable electrode 1130B. In other words, in this modified example, the upper plate 1120 is configured to use the first fixed electrode 114A of the lower plate 115 in the variable capacitor 110 or 1100 of the above embodiments as the first movable electrode 1130A, and the second fixed electrode 114B as the second movable electrode 1130B. Except for this point, it basically has the same configuration as the lower plate 115 in the variable capacitor 110 or 1100 of the above embodiments.

[0192] Furthermore, in the variable capacitor 11000 of this modified example, a conductive coil spring CCS (coil spring CS3 in the case shown in Figure 14) is fixed to the gold flash GF provided on the second movable electrode 1130B of the upper plate 1120 by a fixing means (not shown) such as conductive adhesive or soldering.The variable capacitor 11000 as a weight detection device 1000 is constructed by placing the upper plate 1120 on the lower plate 1150 so that the conductive coil spring CCS and the area on the fixed electrode 1140 on the lower plate 1150 where the gold flash GF is applied are in contact.At this time, the position is adjusted so that the first movable electrode 1130A and the fixed electrode 1140 are in opposing positions, and the upper plate 1120 is placed on the lower plate 1150, and the coil springs CS1 to CS4 are fixed to the upper plate 1120 and the lower plate 1150 by fixing means (not shown), thereby constructing the variable capacitor 11000. The means of fixing the device in this case are the same as in each embodiment.

[0193] In this modified variable capacitor 11000, which functions as a weight detection device 1000, the fixed electrode 1140 and the first movable electrode 1130A function as a parallel plate capacitor, and the fixed electrode 1140 and the second movable electrode 1130B are electrically connected by a conductive coil spring CCS. As a result, in this modified variable capacitor 11000, (a) the fixed electrode 1140 is connected to the second input terminal 120B of the capacitance sensor tag 120 built into the upper plate 1120 via (a1) the second movable electrode 1130B, (a2) a two-layer gold flash GF, and (a3) ​​a conductive coil spring CCS. On the other hand, (b) the first movable electrode 1130A is electrically connected to the first input terminal 120A, and the variable capacitor 11000 is connected between the first and second input terminals 120B.

[0194] In this modified example, the variable capacitor 11000 is constructed by fixing the lower plate 1150 to a fixed object while the upper plate 1120 is positioned above the lower plate 1150 with the four coil springs CS1 to 4 sandwiched in between. As a result, when a product as the object to be measured, MO, is placed on the mounting portion 111 (not shown) of the upper plate 1120 (specifically, the mounting portion 111 provided on the back side of the electrode mounting surface 1120A of the upper plate 1120 shown in Figure 17(B)), the lower plate 1150, which is fixed to the fixed object in the same way as the lower plate 115 of the variable capacitor 110 or 1100 in the above embodiments, does not move. On the other hand, when the coil springs CS1 to 4 elastically deform in accordance with the weight "m" of the mounted object, the upper plate 1120 moves toward the lower plate 1150, and the distance between the first movable electrode 1130A and the fixed electrode 1140 changes, and the capacitance value "C" of the variable capacitor 11000 changes. ｅｘｐ． The capacitance value "C" of the variable capacitor 11000 changes. The electromotive force of the capacitive sensor tag 120 is generated based on the electromagnetic waves transmitted from the RFID reader / writer 20 or the magnetic field generated by the RFID reader / writer 20. ｅｘｐ．The system detects the presence of a coil spring and transmits the corresponding detection data to the RFID reader / writer 20. Meanwhile, the information processing device 30 measures the total weight "m" of the product placed on the placement unit 111 (i.e., the weight "m" of the object to be measured MO) based on the detection data and measurement reference data or calibrated measurement reference data stored in the storage unit, and notifies the user of the measurement result or performs processing for managing the inventory of the product. In Figure 17, an example configuration is shown in which four coil springs CS1 to 4 are installed between the upper plate 1120 and the lower plate 1150. However, a configuration in which four leaf springs LS1 to 4 are installed between the upper plate 1120 and the lower plate 1150 may be adopted, similar to the third embodiment, or five coil springs CS or leaf springs LS may be used, similar to the modified example 2. In this case, similar to the modified example 2, the spring constant of only one spring may be changed to prevent the occurrence of resonance, or all five springs may have the same spring constant. Regardless of which configuration is adopted, the method for generating measurement reference data suitable for the actual characteristics, including the initial characteristics of the variable capacitor 1100 or weight detection device 100, in the information processing device 30 when the variable capacitor 1100 or weight detection device 100 is newly installed, or for calibrating the measurement reference data to suit the characteristics of the variable capacitor 1100 or weight detection device 100 after a state satisfying any of the "characteristic change conditions a to c" occurs, is the same as in each of the embodiments described above. For example, if a configuration is adopted in which four coil springs CS1 to CS4 are installed between the upper plate 1120 and the lower plate 1150 as illustrated in Figure 17, the measurement reference data can be generated or the measurement reference data can be calibrated using the method of the first or second embodiment.

[0195] Furthermore, if a configuration is adopted in which four leaf springs LS1 to 4 are installed between the two (i.e., the upper plate 1120 and the lower plate 1150), the same method as in the third embodiment may be used to (a) determine the values ​​of parameters "A, B, and P" that are suitable for the actual characteristics, including the initial characteristics of the newly installed variable capacitor 11000 or weight detection device 1000, and generate measurement reference data suitable for those characteristics, or (b) determine the values ​​of parameters "A, B, and P" that are suitable for the characteristics of the variable capacitor 11000 or weight detection device 1000 after a state satisfying any of the "characteristic change conditions a to c" has occurred, and calibrate the measurement reference data to generate calibrated measurement reference data suitable for those characteristics. In addition, multiple weight detection devices 1000 of this modified example may be installed in a facility such as a warehouse, and the inventory of goods managed by each weight detection device 1000 may be centrally managed by a single information processing device 3000 using the same method as in the fourth embodiment. In this case, the configuration of the weight detection device used is the same as in the fourth embodiment, except that the configuration of the weight detection device used changes, and the configuration of the product inventory management DB provided in the information processing device 3000 and the processing performed by the information processing device 3000 are the same as in the fourth embodiment, so the details are omitted. In this modified example as well, the fixed electrode 1140 may be configured to be electrically connected to the second movable electrode 1130B or the second input terminal 120B by a conductive wire. In this case, the method of measuring the weight "m" of the object to be measured MO using the measurement reference data or calibrated measurement reference data is the same as in the above embodiments, in which measurement reference data that matches the actual characteristics including the initial characteristics of the newly installed variable capacitor 11000 is generated by the same calibration method as in each embodiment as described above, or calibrated measurement reference data that is suitable for the characteristics of the variable capacitor 11000 after a state that satisfies any of the "characteristic change conditions a to c" occurs is generated.

[0196] When actually installing the weight detection devices 10, 100, or 1000 in a facility such as a warehouse, it is conceivable that the weight detection devices 10, 100, or 1000 will be placed on metal shelves. In this case, if the antenna AN is close to the metal, communication by the capacitive sensor tag 120 may be hindered. On the other hand, with the configuration of this modified example, the antenna AN is installed on the top plate 1120 side, ensuring a distance between the shelf and the antenna AN when installed on a metal shelf, thereby ensuring reliable communication while maintaining an appropriate communication distance. Details of other aspects are the same as in the above embodiments, so they are omitted.

[0197] 1, 1B...Weight measurement system, 10, 100, 1000...Weight detection device, 110, 1100, 11000...Variable capacitor, 111...Mounting section, 112, 1120...Upper plate, 112A, 115A, 1120A, 1150A...Electrode mounting surface, 113...Movable electrode, 1130A...First movable electrode, 1130B...Second movable electrode, 114A...First fixed electrode, 114B... Second fixed electrode, 1140... Fixed electrode, 115, 1150... Lower plate, 120... Capacitive sensor tag, 20... RFID reader / writer, 30, 300, 3000... Information processing device, CS1-4... Coil spring, CCS... Conductive coil spring, RF... Resist film, GF... Gold flash, FM... Fixing means, LS1-4... Leaf spring, CLS... Conductive leaf spring, MO... Object to be measured,

Claims

1. A variable capacitor comprising two members connected to each other by an elastic member, (1) a first member that is movable when a load or pressure is applied and has a movable electrode, and (2) a second member that has a fixed electrode positioned opposite to the movable electrode and does not move even when a load or pressure is applied to the first member, wherein the elastic member elastically deforms in accordance with the applied load or pressure, and the capacitance value changes due to the change in the distance between the movable electrode and the fixed electrode when the first member moves, and a capacitance sensor electrically connected to the variable capacitor that detects the capacitance value of the variable capacitor and transmits corresponding detection data wirelessly, A physical quantity measurement system characterized by comprising: (1) data defining the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, which includes the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and reference data obtained by a predetermined calculation based on the result of pre-measurement of the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor; and (2) a physical quantity measurement device that measures the value of the load or pressure applied to the first member based on the detection data wirelessly transmitted by the capacitance sensor, and performs processing based on the measurement result.

2. The physical quantity measuring device generates reference data by determining the values ​​of the first and second parameters suitable for the characteristics of the variable capacitor, by performing calculations based on a first mathematical formula that includes unknown first and second parameters as a predetermined calculation and defines the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor, with respect to the measurement results, which include the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and the values ​​of the first and second parameters suitable for the characteristics of the variable capacitor, respectively; and (b) measuring the value of the load or pressure applied to the first member based on the detection data.

3. The physical quantity measuring device, instead of the reference data generated by calculation based on the first formula, (a) measurement results of at least three points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and a calculation based on a second formula which defines the relationship between the capacitance value of the variable capacitor and the load or pressure applied to the first member, is performed as a predetermined calculation on the measurement results, by adding an unknown third parameter to the first formula, thereby determining the values ​​of the first to third parameters in the second formula that are suitable for the characteristics of the variable capacitor and generating the reference data, and (b) measuring the value of the load or pressure applied to the first member based on the detection data.

4. The physical quantity measuring device (A) when the variable capacitor is newly installed, obtains measurement results from at least two points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and determines the values ​​of the first and second parameters in the first formula that are suitable for the characteristics including the initial characteristics of the variable capacitor by regression analysis based on the first formula on the measurement results, and generates the reference data suitable for the initial characteristics of the variable capacitor based on the determined values ​​of the first and second parameters, and (a) measures the value of the load or pressure applied to the first member using the generated reference data, (B) If a condition is met after the installation of the variable capacitor, the physical quantity measurement system according to claim 2, wherein, while obtaining measurement results from at least two points where the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, the values ​​of the first and second parameters suitable for the characteristics of the variable capacitor after the condition is met are determined by regression analysis based on the first mathematical formula on the measurement results, the reference data is calibrated based on the determined values ​​of the first and second parameters to generate calibrated reference data suitable for the characteristics of the variable capacitor after the condition is met, and the value of the load or pressure applied to the first member is measured using the calibrated reference data instead of the reference data generated at the time of initial installation.

5. The physical quantity measuring device, (A) when the variable capacitor is newly installed, obtains measurement results from at least two points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and determines the values ​​of the first and second parameters in the first formula that are suitable for the characteristics including the initial characteristics of the variable capacitor by calculation based on the third formula calculated based on the first formula on the said measurement results, generates the reference data suitable for the characteristics including the initial characteristics of the variable capacitor based on the determined values ​​of the first and second parameters, and measures the value of the load or pressure applied to the first member using the reference data, (B) If a condition is met after the installation of the variable capacitor, the physical quantity measurement system according to claim 2, wherein, while obtaining measurement results from at least two points where the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, the values ​​of the first and second parameters in the first formula that are suitable for the characteristics of the variable capacitor after the condition is met are determined by calculation based on the third formula, the reference data is calibrated based on the determined values ​​of the first and second parameters to generate calibrated reference data suitable for the characteristics of the variable capacitor after the condition is met, and the value of the load or pressure applied to the first member is measured using the calibrated reference data instead of the reference data generated at the time of initial installation.

6. The physical quantity measuring device, (A) when the variable capacitor is newly installed, obtains measurement results from at least three points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and determines the values ​​of the first to third parameters in the second formula that are suitable for the characteristics including the initial characteristics of the variable capacitor by performing regression analysis based on the second formula on the measurement results, generates the reference data suitable for the characteristics including the initial characteristics of the variable capacitor based on the determined values ​​of the first to third parameters, and measures the value of the load or pressure applied to the first member using the generated reference data, (B) If a condition that satisfies predetermined conditions occurs after the installation of the variable capacitor, the system obtains measurement results from at least three points where the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, and determines the values ​​of the first to third parameters in the second formula that are suitable for the characteristics of the variable capacitor after the condition occurs by performing regression analysis on the measurement results based on the second formula, calibrates the reference data based on the determined values ​​of the first to third parameters to generate calibrated reference data that is suitable for the characteristics of the variable capacitor after the condition occurs, and measures the value of the load or pressure applied to the first member using the calibrated reference data instead of the reference data generated at the time of initial installation, according to claim 3.

7. The physical quantity measuring device, (A) when the variable capacitor is newly installed, obtains measurement results from at least three points in which the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member, and based on said measurement results, determines the values ​​of the first to third parameters in the second formula that are suitable for the characteristics including the initial characteristics of the variable capacitor, based on a predetermined group of formulas, generates the reference data suitable for the characteristics including the initial characteristics of the variable capacitor based on the determined values ​​of the first to third parameters, and measures the value of the load or pressure applied to the first member using said reference data, (B) If a condition that satisfies predetermined conditions occurs after the installation of the variable capacitor, the physical quantity measurement system according to claim 3, wherein the relationship between the value of the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured and measurement results are obtained from at least three points, and based on the measurement results, the values ​​of the first to third parameters in the second formula that are suitable for the characteristics of the variable capacitor after the condition occurs are determined based on the predetermined group of formulas, and the reference data is calibrated based on the determined values ​​of the first to third parameters to generate calibrated reference data that is suitable for the characteristics of the variable capacitor after the condition occurs, and the value of the load or pressure applied to the first member is measured using the calibrated reference data instead of the reference data generated at the time of initial installation.

8. A physical quantity measurement system according to any one of claims 1 to 7, wherein a plurality of physical quantity detection devices, each comprising a variable capacitor and a capacitance sensor, are installed at different locations in real space, and the physical quantity measurement device has a storage means that stores the reference data or calibrated reference data corresponding to each of the plurality of physical quantity detection devices in association with identification information for identifying the physical quantity detection device, and the system wirelessly acquires (a1) the detection data corresponding to the capacitance value of the variable capacitor constituting the physical quantity detection device, and (a2) the identification information corresponding to the physical quantity detection device, from each of the capacitance sensors constituting the plurality of physical quantity detection devices, in association with (a1) the detection data, and (a2) the identification information corresponding to the physical quantity detection device, and individually measures the value of the load or pressure applied to the first member of each physical quantity detection device based on (b1) the detection data acquired in association with the identification information, and (b2) the reference data or calibrated reference data stored in the storage means in association with the acquired identification information, and performs processing based on the measurement results.

9. The physical quantity measurement system according to claim 8, wherein the storage means stores product attribute information indicating the attributes of a product whose inventory is managed using the corresponding physical quantity detection device, in association with the identification information and the reference data, and the physical quantity measuring device measures the load applied to the first member as the weight value of the product whose inventory is managed using the physical quantity detection device, based on the acquired detection data and the reference data or calibrated reference data corresponding to the physical quantity detection device that is the source of the acquisition of the detection data, and performs a process to manage the inventory of the product managed using each physical quantity detection device based on the measured load and the product attribute information of the corresponding product stored in the storage means.

10. The physical quantity measurement system according to any one of claims 1 to 7, wherein the capacitance sensor is configured as an RFID tag, generates an electromotive force based on electromagnetic waves transmitted by the physical quantity measuring device or other device, or a magnetic field generated by the information processing device or other device, detects the capacitance value of the variable capacitor using the electromotive force, and wirelessly transmits the detection data corresponding to the detection result to the physical quantity measuring device.

11. The physical quantity measurement system according to claim 8, wherein the capacitance sensor is configured as an RFID tag, generates an electromotive force based on electromagnetic waves transmitted by the physical quantity measuring device or other device, or a magnetic field generated by the information processing device or other device, detects the capacitance value of the variable capacitor using the electromotive force, and wirelessly transmits the detection data corresponding to the detection result to the physical quantity measuring device.

12. The physical quantity measurement system according to claim 9, wherein the capacitance sensor is configured as an RFID tag, generates an electromotive force based on electromagnetic waves transmitted by the physical quantity measuring device or other device, or a magnetic field generated by the information processing device or other device, detects the capacitance value of the variable capacitor using the electromotive force, and wirelessly transmits the detection data corresponding to the detection result to the physical quantity measuring device.

13. A variable capacitor comprising two members connected opposite to each other by an elastic member, wherein (1) a first member that is movable when a load or pressure is applied and has a movable electrode, and (2) a second member that has a fixed electrode positioned opposite to the movable electrode and does not move even when a load or pressure is applied to the first member, and the capacitance value changes due to the change in the distance between the movable electrode and the fixed electrode when the first member moves, as the elastic member elastically deforms in response to the applied load or pressure, A physical quantity detection device comprising: a capacitance sensor electrically connected to the variable capacitor, which detects the capacitance value of the variable capacitor and generates corresponding detection data, and wirelessly transmits the detection data to a physical quantity measuring device that measures the load or pressure applied to the first member using reference data generated by performing calculations based on a first mathematical formula that includes unknown first and second parameters and defines the relationship between the capacitance value of the variable capacitor and the load or pressure applied to the first member, on at least two measurement results in which the relationship between the load or pressure applied to the first member and the capacitance value of the variable capacitor is actually measured, including the measurement result of the capacitance value of the variable capacitor when no load or pressure is applied to the first member; and determining the values ​​of the first and second parameters suitable for the characteristics of the variable capacitor, respectively, using the generated reference data; and performing processing based on the measurement results.

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