JP7093924B2 - Non-contact measurement system - Google Patents

Description

The present invention relates to a non-contact measurement system, and more particularly to a non-contact measurement system for measuring the presence or absence of conductivity and conductivity of a substance containing a liquid or gel as a measurement target.

Conventionally, when manufacturing liquid foods and chemicals, the fact that the solution concentration of the substance deviates from the desired value means a change in the manufacturing process such as contamination of foreign substances or modulation of the mixing ratio. It is known that the solution concentration needs to be strictly controlled.

As a method for controlling such a solution concentration, for example, a measuring device that measures a solution concentration by immersing a pair of probes made of metal in a solution, measuring the current flowing between the probes, and detecting the conductivity is known. Has been done. In this measuring device, since the metal probe is directly immersed in the liquid, the probe may corrode depending on the liquid to be measured, and accurate measurement may not be possible.

To solve these problems, a conductivity measuring device in which a metal probe is completely coated with a resin has been proposed (see Patent Document 1). According to the proposed conductivity measuring device, the problem of probe corrosion can be avoided because the metal probe portion does not come into direct contact with the liquid to be measured.

Further, in Patent Document 2, two sets of two pairs of measurement electrodes are provided, a correction coefficient is calculated from the conductivity signal of the two sets of measurement electrodes, and the change in the cell constant is calibrated by the correction coefficient. A measuring device for displaying the above is disclosed. According to this configuration, the measurement error due to the dirt on the measuring electrode can be reduced, and the measurement can be performed with high accuracy.

Japanese Unexamined Patent Publication No. 11-304856 Japanese Unexamined Patent Publication No. 07-055744

However, in any of the above configurations, the sensor portion of the measuring device must be brought into contact with the liquid to be measured in the end, and the problem of contamination of the measuring object due to immersion of the sensor has not been solved yet.

Therefore, as a result of diligent studies on such a problem, the present inventors have developed a non-contact measurement system that solves the problem of contamination of the measurement object by measuring the measurement object in a non-contact manner using a capacitance type sensor. I came up with a proposal. Further, in this non-contact measurement system, the present inventors have a capacitance value or a regulation obtained as a result of measurement depending on the measurement frequency of the AC voltage for measuring the capacitance value of the capacitance type sensor. We have found that the region where the difference from the capacitance value (hereinafter referred to as the difference) corresponds to the fluctuation of the observation parameter of the measurement object is different, and arrived at the present invention.

An object of the present invention is to provide a non-contact measurement system capable of high-sensitivity and high-precision measurement by setting an appropriate measurement frequency according to an object of measurement and an observation parameter of an object to be measured.

In order to solve the above-mentioned problems, the non-contact measurement system described in one embodiment is for the object to be measured without contacting the container for the object to be measured containing the object to be measured and the object to be measured. By connecting a capacitance type sensor arranged in a contact state or a non-contact state in the vicinity of the container to the capacitance type sensor and applying an AC voltage to the capacitance type sensor at a predetermined measurement frequency. It is a non-contact measurement system including a measuring device for measuring a capacitance value, and the measuring device is acquired in a preliminary measurement performed by accommodating a solution having a known concentration in the container for an object to be measured. A storage unit that stores the capacitance value, and a measurement unit that acquires the capacitance value by applying an AC voltage of the measurement frequency to a solution of unknown concentration contained in the container for the object to be measured. , A control that calculates the difference between the capacitance value stored in the storage unit and the capacitance value obtained from the solution having an unknown concentration, and determines whether the calculated difference is within the allowable range. A unit and a warning unit that warns when the difference is determined to be out of the allowable range by the control unit are provided, and the measurement frequency is set according to a region of the value of the observation parameter of the measurement object. It is characterized by that.

In the non-contact measurement system described in another embodiment, the container for a measured object containing the object to be measured is in contact with or not in contact with the object to be measured in the vicinity of the container to be measured without contacting the object to be measured. Measurement that measures the capacitance value by connecting the capacitance type sensor arranged in contact state and the capacitance type sensor and applying an AC voltage to the capacitance type sensor at a predetermined measurement frequency. A non-contact measurement system equipped with a device, wherein the measurement device is a reference obtained in a measurement performed in a state where a solution having a known concentration as a reference is contained in the container for an object to be measured. The difference in capacitance obtained in the measurement performed with a plurality of known solutions having different concentrations contained in the container for the object to be measured from the capacitance is calculated for each concentration of the solution used for the measurement. It is characterized in that it is provided with a storage unit for storing as a reference capacitance value difference change model associated with the measurement frequency .

It is a figure which shows the structural example of the non-contact measurement system of this embodiment. It is a figure which shows the schematic structure of the capacitance type sensor part. It is a functional block diagram which shows the structural example of the non-contact measurement system of this embodiment. It is a figure which shows the change of the capacitance value (difference) with respect to the concentration change of the KCl solution at three different measurement frequencies. It is a figure which shows the equivalent circuit of the non-contact measurement system when the electrode connected to the ground is used as an auxiliary electrode 400. It is a figure which shows the state of the change of the difference from the specified capacitance value with respect to the change of frequency in the KCl solution of each different concentration.

Hereinafter, embodiments of the present invention will be described in detail.

FIG. 1 is a diagram showing a configuration example of the non-contact measurement system of the present embodiment, and FIG. 2 is a diagram showing a schematic configuration of a capacitance type sensor unit. In the non-contact measurement system of the present embodiment, the capacitance type sensor unit 100, the measuring device 200 electrically connected to the capacitance type sensor unit 100, the liquid of the object to be measured, and the like are accommodated. It is configured to include a container for measuring objects 300 and an auxiliary electrode 400.

In the non-contact measurement system of the present embodiment, the electrostatic capacity is arranged in contact or non-contact state in the vicinity of the container 300 for measurement while the object to be measured is housed in the container 300 for measurement. An AC voltage can be applied to the type sensor 100 by the measuring device 200 to measure the capacitance value of the entire non-contact measurement system. In the non-contact measurement system of the present embodiment, by appropriately changing the frequency (measurement frequency) of the applied AC voltage according to the purpose of measurement and the object to be measured, measurement with high measurement sensitivity and measurement accuracy becomes possible. ..

The object to be measured may be a substance containing a liquid or a gel, and examples thereof include foods / chemicals, chemically reactive solutions, high-temperature solutions, and emulsion / suspension solutions. The object to be measured is housed in the container 300 for the object to be measured.

The capacitance type sensor unit 100 is housed when a conductive substance is housed in the device to be measured 300 in a state of being arranged in a contact state or a non-contact state in the vicinity of the container for the object to be measured 300. A known capacitance type sensor capable of forming a capacitance with the material can be used. For example, two sensors formed so that the comb teeth face each other on one side of the base material. It can be a mutual capacitance type capacitive sensor formed of a comb tooth type electrode or two asymmetric flat plate electrodes having different areas and formed so as to face each other on both sides of a base material.

The base material used in the capacitance type sensor unit 100 can be, for example, a thin film made of a material such as polyethylene terephthalate, polyethylene naphthalate, or polyimide. Further, the detection electrode used in the capacitance type sensor unit 100 can be made of a conductive material such as copper, silver, gold, aluminum, nickel, tin, or carbon, and a screen using these materials can be used. The sensor can be formed by various methods such as a printing method such as a printing method, a vapor deposition method, and a sputtering method.

The capacitance type sensor unit 100 defines a detection range by using an electric field indicated by electric lines of force from one of the two electrodes to the other. When an object having conductivity enters the detection range of the capacitance type sensor unit 100, a part of the electric lines of force is absorbed by the object and the capacitance value of the capacitance type sensor unit 100 decreases.

Further, in the non-contact measurement system according to the present embodiment, a capacitance type sensor as described in Patent Document 3 is used as the capacitance type sensor unit 100. Specifically, as shown in FIG. 2, the capacitance type sensor unit 100 includes a base material 101, a first electrode 102 ₁ formed on the first surface of the base material 101, and a base material 101. The second electrode 102 ₂ formed on the second surface opposite to the first surface of the first surface, and the first lead-out wiring drawn out on the first surface to apply a voltage to the first electrode 102 ₁ . Includes 103 ₁ and a second lead-out wire 103 ₂ that is drawn out at the second surface and applies a voltage to the second electrode 102 ₂ .

In the capacitance type sensor unit 100 according to the present embodiment, the first electrode 102 ₁ and the second electrode 102 ₂ are via the first lead-out wiring 103 ₁ and the second lead-out wiring 103 ₂ , respectively. It is connected to the measuring unit 200.

The first electrode 102 ₁ and the second electrode 102 ₂ and the first lead wire 103 ₁ and the second lead wire 103 ₂ are conductive materials such as copper, silver, gold, aluminum, nickel, tin, and carbon. It can be formed by using a printing method such as a screen printing method.

For example, when the first electrode 102 ₁ is a signal electrode, the second electrode 102 ₂ is a ground electrode, and the container for the object to be measured 300 is on the side of the first electrode 102 ₁ which is a signal electrode, it functions as a ground electrode. The second electrode 102 ₂ is configured to have a larger area than the first electrode 102 ₁ .

The measuring device 200 applies an AC voltage having a predetermined amplitude at a predetermined frequency to the capacitance type sensor unit 100 to obtain a capacitance value of the entire non-contact measurement system including the capacitance type sensor unit 100. Measure.

In the present embodiment, the capacitance type sensor unit 100 is arranged in the vicinity of the container for the object to be measured 300 in a contact state or a non-contact state. Specifically, the capacitance type sensor unit 100 may be simply placed at a position in the vicinity of the container 300 to be measured, although it does not come into contact with the container 300 to be measured, or the capacitance type sensor unit 100 may be placed with respect to the container 300 to be measured. Then, for example, by a printing method such as affixing or screen printing, a vapor deposition method, a sputtering method, or the like, the capacitance type sensor unit is placed on the surface of the container for the object to be measured 300 on the surface opposite to the surface in contact with the object to be measured. 100 may be provided.

FIG. 3 is a functional block diagram showing a configuration example of the non-contact measurement system of the present embodiment. As shown in FIG. 3, the measuring device 200 obtains the capacitance value of the entire non-contact measurement system including the high-frequency power supply 201 that applies an AC voltage of a predetermined amplitude at a predetermined frequency and the capacitance type sensor unit 100. It is configured to include a measuring unit 202 for measurement, a control unit 203 for appropriately controlling the high frequency power supply 201, the measuring unit 202, and a storage unit 204, and a storage unit 204 for storing the measured capacitance value and the like. The high frequency power supply 201 and the measuring unit 202 of the measuring device 200 are connected to the capacitance type sensor unit 100.

The high-frequency power supply 201 is controlled by the control unit 203 to apply an AC voltage having a predetermined amplitude to the connected capacitance type sensor unit 100 and the measurement unit 202 at a predetermined frequency (measurement frequency). In the non-contact measurement system of the present embodiment, the region (sensitivity threshold) in which the capacitance value (difference) obtained as a result of measurement corresponds to the fluctuation of the observation parameter of the measurement object depending on the measurement frequency applied in the high frequency power supply 201. (Also known as) is different, so it is possible to make settings for high-sensitivity and high-precision measurement by utilizing this characteristic.

FIG. 4 is a diagram showing the results of measuring the capacitance values (differences) of KCl solutions having a plurality of concentrations at three different measurement frequencies. For example, according to FIG. 4, when the measurement frequencies are 10 kHz, 100 kHz, and 1000 kHz, the capacitance values (differences) of the KCl solutions having a plurality of concentrations (that is, the observation parameters are varied) are measured. However, it can be seen that the region where the fluctuation of the capacitance value (difference), which is the measurement result, is large differs depending on the measurement frequency. Specifically, the capacitance value (difference) is in the vicinity of 0.0001 mM to 0.01 mM at 10 kHz, in the vicinity of 0.001 mM to 0.5 mM at 100 kHz, and in the vicinity of 0.1 mM to 1 mM at 1000 kHz. It can be said that it corresponds well to the fluctuation of the observation parameters of the object to be measured.

In the example shown in FIG. 4, the region where the capacitance value (difference), which is the measurement result, fluctuates for each measurement frequency can be set as the detection region. In the detection region, it can be said that the sensitivity is high when the maximum response amount, which is the difference between the response amounts between the upper limit of detection and the lower limit of detection, is large and the slope of fluctuation is large.

In one embodiment, the control unit 203 sets the measurement frequency in the high frequency power supply 201 according to the value region of the observation parameter of the measurement object. The value region of the observation parameter of the measurement target is, for example, a region in which the concentration value is estimated to exist when the concentration of the measurement target is used as the observation parameter. Therefore, a measurement frequency having a detection region can be used in the value region of the observation parameter of the measurement object. Furthermore, it is preferable to adopt a highly sensitive detection region in the value region of the observation parameter of the measurement object in order to realize highly sensitive and accurate measurement.

In another aspect, the control unit 203 can sweep the measured frequency in the high frequency power supply 201. By sweeping, when the value of the observation parameter cannot be estimated, the measurement can be performed in a wider area.

Returning to FIG. 1, when the container 300 for an object to be measured is arranged in a contact state or a non-contact state in the vicinity of the capacitance type sensor unit 100, it is covered so as to be separated from the capacitance type sensor unit 100. It is a means for holding the measured object, and can be made of a non-conductive material such as a transparent styrene case, glass, polyvinyl chloride, or polytetrafluoroethylene. In the present embodiment, the pool type configuration is exemplified as the container 300 for the object to be measured, but various embodiments including the shape and size thereof, for example, a conduit type configured to allow the object to be measured to flow in, etc. Can be taken.

The auxiliary electrode 400 is an electrode arranged adjacent to the object container 300 to be measured, and is arranged sufficiently separated from the capacitance type sensor unit 100 so as not to interfere with the detection space of the capacitance type sensor unit 100. Will be done. The auxiliary electrode 400 may be configured as a ground electrode connected to the ground or as a floating electrode not connected to the ground. Although the auxiliary electrode 400 is not an indispensable configuration, it is effective in that the stability and sensitivity of the measurement in the measuring device 200 can be improved, and the configuration is also configured as a ground electrode rather than as a floating electrode. Is more preferable in exerting these effects.

FIG. 5 is a diagram showing an equivalent circuit of a non-contact measurement system when a ground electrode is used as the auxiliary electrode 400. In the non-contact measurement system of the present embodiment, the capacitance C _m formed in the capacitance type sensor unit 100, each of the two electrodes of the capacitance type sensor unit 100, and the measurement target are measured with respect to the high frequency power supply 201. The capacitances C ₁ and C ₂ formed between the object and the resistance value R of the object to be measured having conductivity and the static electrode 400 formed between the object to be measured and the auxiliary electrode 400 connected to the ground. It is configured to be connected to the electric capacity C ₃ .

As shown in FIG. 5, since the equivalent circuit of the non-contact measurement system of the present embodiment has a configuration in which the CR component formed by the object to be measured is connected to the high frequency power supply 201, the measurement is performed with respect to the frequency of the high frequency power supply 201. It is considered to have dependent characteristics depending on the physical properties of the object. The present inventors have found that this dependent characteristic lies in the solution concentration of the object to be measured, and have proposed the following measurement method for measuring the concentration of the object to be measured with high sensitivity and high accuracy.

The non-contact measurement system of the present embodiment utilizes the characteristic that the sensitivity threshold for the concentration, which is an observation parameter, changes when the measurement frequency in the measuring device 200 is changed, according to the purpose of measurement, the object to be measured, and its concentration. By setting an appropriate frequency, highly sensitive and highly accurate measurement becomes possible. The measurement method of the non-contact measurement system of the present embodiment will be described below.

(First measurement method)
First, the first measurement method in the non-contact measurement system will be described. This measurement method is a method of measuring by fixing the frequency to an appropriate frequency according to the concentration range of the object to be measured for the purpose of qualitatively evaluating changes in the concentration of the object to be measured and contamination of foreign substances.

In this measurement method, before the measurement of the object to be measured, the capacitance value is measured in a state where a solution having a known predetermined concentration is contained in the container 300 for the object to be measured (preliminary measurement). In the preliminary measurement, the control unit 203 stores the capacitance value obtained by measuring the solution of a known concentration as the measurement object by the measurement unit 202 in the storage unit 204 with the measurement frequency of the high frequency power supply 201 fixed. I will do it. A solution having a known predetermined concentration is set as a reference concentration, and is stored in the storage unit 204 together with the capacitance value at that time.

Next, the measurement is performed with the object to be measured having an unknown concentration contained in the container 300 for the object to be measured. The control unit 203 acquires the capacitance value by the measurement unit 202 in a state where the measurement frequency of the high frequency power supply 201 is fixed to the same frequency as before.

The control unit 203 calculates the difference between the capacitance value stored in the storage unit 204 and the acquired capacitance value. It is determined whether or not the calculated difference is within the allowable range.

When the control unit 203 determines that the calculated difference is not within the allowable range, the control unit 203 gives a warning by a warning means (not shown) or the like. The warning may include a warning sound (warning voice) or a warning display (warning lamp).

The notification of the result of the determination may be a mode of warning only when it is not within the permissible range, or may be a mode of displaying that it is normal when it is within the permissible range.

By increasing the frequency of measurement in the control unit 203, it is possible to quickly detect when the detected difference is out of the permissible range, so that the detection accuracy can be improved.

According to this measurement method, qualitative evaluations such as changes in the concentration of the object to be measured and contamination of foreign substances can be performed with high sensitivity and quickly.

(Second measurement method)
The second measurement method in the non-contact measurement system of the present embodiment is fixed at an appropriate frequency according to the concentration range of the measurement target for the purpose of quantitatively evaluating the value of the concentration of the measurement target. It is a method of measuring.

In this measurement method, before the measurement of the object to be measured, two or more kinds of solutions having known concentrations are measured in a state where the solutions of each concentration are housed in the container 300 for the object to be measured, respectively, and the obtained 2 is obtained. Two or more sets of data are stored in the storage unit 204 by combining one or more capacitance values with the concentration of the solution used for the measurement (preliminary measurement). As the measurement frequency in the preliminary measurement, one or more frequencies having detection sensitivity according to the estimated concentration of the object to be measured can be selected. The measurement for two or more kinds of known concentration solutions may be performed for all kinds at the time of actual measurement, or the measurement is performed for the solution excluding one or more predetermined concentrations at the time of shipment from the factory, and the actual measurement is performed. At the time of measurement, the measurement may be performed on the remaining solution having one or more concentrations. For example, if the number of known concentrations is two, one is measured at the time of shipment of the non-contact measurement system, and the remaining one is measured at the time of actual object measurement, or the non-contact measurement system is shipped. Sometimes the measurement is not performed, and all two types may be measured at the time of actual object measurement. For example, when the number of known concentrations is three, one type is measured at the time of shipment of the non-contact measurement system, and the remaining two types are measured at the time of actual object measurement, or the non-contact measurement system is shipped. Sometimes two types are measured and the remaining one is measured when actually measuring the object, or when the non-contact measurement system is shipped, no measurement is performed and all three types are measured when actually measuring the object. You may.

Next, the measurement is performed with the object to be measured having an unknown concentration contained in the container 300 for the object to be measured. The control unit 203 acquires the capacitance value by the measurement unit 202 in a state where the measurement frequency of the high frequency power supply 201 is fixed. The fixed measurement frequency can be selected from one or more frequencies used in the preliminary measurement. In this method, since the measurement is performed with the measurement frequency fixed, it is possible to quickly acquire the capacitance value.

When the acquired capacitance value is a value in the range of two or more capacitance values stored in the preliminary measurement, the concentration corresponding to the acquired capacitance value is obtained by interpolation. If the acquired capacitance value is not within the range of the two or more capacitance values stored in the preliminary measurement, the concentration expected from the two or more capacitance values is obtained by extrapolation.

As described above, in this measurement method, quantitative evaluation such as the value of the concentration of the object to be measured can be performed with high sensitivity and quickly.

(Third measurement method)
The third measurement method in the non-contact measurement system of the present embodiment performs measurement by sweeping without fixing the measurement frequency for the purpose of qualitatively evaluating changes in the concentration of the object to be measured and contamination of foreign matter. It is a method.

In this measurement method, before the measurement of the object to be measured, the capacitance value is measured with a solution having a known concentration contained in the container 300 for the object to be measured (preliminary measurement). In the preliminary measurement, the control unit 203 stores the capacitance value obtained by measuring the solution of a known concentration as the measurement object by the measurement unit 202 in the storage unit 204 while sweeping the measurement frequency of the high frequency power supply 201. Keep it. A solution having a known concentration is set as a reference concentration, and the capacitance value at that time is associated with the measurement frequency and stored in the storage unit 204 as a reference capacitance value change model (frequency characteristic).

Next, the measurement is performed with the object to be measured contained in the container 300 for the object to be measured. The control unit 203 acquires the capacitance value by the measurement unit 202 while sweeping the measurement frequency of the high frequency power supply 201. The acquired capacitance value is stored in the storage unit 204 as a capacitance value change model measured in association with the measurement frequency. In this method, the frequency is swept to acquire the capacitance value, so that a more accurate value can be acquired.

The control unit 203 fits the reference capacitance value change model stored in the preliminary measurement and the measured capacitance value change model, and determines whether or not they match. Whether or not they match is determined by considering some error.

If both match, it can be determined that there is no change in concentration or no foreign matter is mixed. On the other hand, if the two do not match, it can be determined that the concentration has changed or that foreign matter has been mixed.

As a result of the determination, as in the first measurement method, a warning or the like can be given as necessary by a warning means (not shown) or the like.

As described above, in this measurement method, it is possible to perform qualitative evaluation such as change in concentration of the object to be measured and contamination of foreign matter with high sensitivity and high accuracy.

(Fourth measurement method)
The fourth measurement method in the non-contact measurement system of the present embodiment is a method of performing measurement by sweeping without fixing the measurement frequency for the purpose of quantitatively evaluating the value of the concentration of the object to be measured. ..

In this measurement method, before the measurement of the object to be measured, a solution having a known concentration as a reference and a solution having a plurality of known different concentrations are contained in a container 300 for a measured object. For each concentration of the solution used for the measurement, the difference from the reference capacitance value of the acquired capacitance value is associated with the measurement frequency and the reference capacitance value difference change model (frequency). It is stored in the storage unit 204 as a characteristic) (preliminary measurement). Measurements for a plurality of types of known concentrations may be performed for all types during the actual measurement, or may be performed for a solution having a concentration other than one or more predetermined at the time of shipment from the factory, and the actual measurement may be performed. It may be done with the remaining one or more concentrations of solution.

Next, the measurement is performed with the object to be measured contained in the container 300 for the object to be measured. The control unit 203 acquires the capacitance value by the measurement unit 202 while sweeping the measurement frequency of the high frequency power supply 201.

The acquired capacitance value is plotted in association with the frequency and fitted to the reference capacitance value change model stored in the preliminary measurement. As a result of fitting, the concentration of the object to be measured can be estimated based on the concentration of the solution measured by the model that fits best.

FIG. 6 is a diagram showing a model (frequency characteristic) of the change in the difference in capacitance value with respect to the frequency change of the KCl solution having each concentration. For example, as shown in FIG. 6, when a KCl solution is used as a measurement object, the change in the difference in capacitance value with respect to the frequency change has a different shape for each concentration as shown in FIG. In the example of FIG. 6, distilled water before containing KCl is used as a reference solution, and the difference from the capacitance value in the distilled water before containing KCl is shown with respect to the frequency change. Therefore, the control unit 203 of the KCl solution, which is the measurement target, is based on which model the shape of the change in the difference in the capacitance value with respect to the frequency change of the KCl solution, which is the measurement target, is close to. The concentration can be estimated. According to this method, the capacitance value is measured at more measurement points, so that it can be said that the measurement can be performed with higher accuracy.

As described above, in this measurement method, quantitative evaluation such as the value of the concentration of the object to be measured can be performed with high sensitivity and high accuracy.

100 Capacitance type sensor unit 200 Measuring device 201 High frequency power supply 202 Measuring unit 203 Control unit 204 Storage unit 300 Container for measured object 400 Auxiliary electrode

Claims (8)

A container for the object to be measured that houses the object to be measured,
Capacitance type sensors arranged in contact or non-contact near the container for the object to be measured without contacting the object to be measured.
A non-contact measurement system provided with a measuring device connected to the capacitance type sensor and measuring a capacitance value by applying an AC voltage to the capacitance type sensor at a predetermined measurement frequency.
The measuring device includes a storage unit that stores a capacitance value acquired in a preliminary measurement performed by accommodating a solution having a known concentration in the container for an object to be measured.
A measuring unit that obtains a capacitance value by applying an AC voltage at the measurement frequency to a solution of unknown concentration contained in the container for the object to be measured.
A control unit that calculates the difference between the capacitance value stored in the storage unit and the capacitance value obtained from the solution having an unknown concentration, and determines whether the calculated difference is within the allowable range. When,
A warning unit for giving a warning when the control unit determines that the difference is not within the allowable range is provided.
A non-contact measurement system characterized in that the measurement frequency is set according to a region of values of observation parameters of the measurement object. The non-contact measurement system according to claim 1 , wherein the measuring device performs the measurement while sweeping the measurement frequency. A container for the object to be measured that houses the object to be measured,
Capacitance type sensors arranged in contact or non-contact near the container for the object to be measured without contacting the object to be measured.
It is a non-contact measurement system provided with a measuring device connected to the capacitance type sensor and measuring the capacitance value by applying an AC voltage to the capacitance type sensor while sweeping the measurement frequency. ,
The measuring device has a plurality of known different concentrations from the reference capacitance obtained in the measurement performed with the solution of the known concentration as one reference contained in the container for the object to be measured. The difference in capacitance obtained in the measurement performed with the solution contained in the container for the object to be measured is the reference electrostatic associated with the measurement frequency for each concentration of the solution used in the measurement. A non-contact measurement system characterized by having a storage unit for storing as a capacitance value difference change model. A claim characterized by further provided with an auxiliary electrode arranged in the vicinity of the container for the object to be measured without contacting the object to be measured at a position not interfering with the detection space of the capacitance type sensor. The non-contact measurement system according to any one of Items 1 to 3 . The non-contact measurement system according to claim 4 , wherein the auxiliary electrode is a floating electrode. The non-contact measurement system according to claim 4 , wherein the auxiliary electrode is a ground electrode. The non-contact measurement system according to claim 1 or 2 , wherein the measuring device performs a qualitative evaluation of the measurement object based on the measurement result. The non-contact measurement system according to claim 3 , wherein the measuring device quantitatively evaluates the object to be measured based on the result of the measurement.

Images