JP4360232B2 - Capacitive load cell - Google Patents

Description

  The present invention relates to a capacitive load cell.

  In general, as shown in FIG. 5, the capacitance type load cell has a configuration as a so-called capacitor in which electrodes 2 and 3 are opposed to each other with a dielectric 1 interposed therebetween, and changes when a load is applied. The load is obtained by measuring the capacitance.

That is, the capacitance C in the capacitance type load cell is
[Equation 1]
C = ε ₀ · ε _r · S / d
Where ε ₀ : dielectric constant of vacuum ε _r : relative dielectric constant S: area of dielectric d: distance between electrodes, but when a load is applied to a capacitance load meter, the distance between electrodes The capacitance C changes with the change of d.

Here, from the Hooke's law that the strain of the elastic body is proportional to the stress, if the inter-electrode distance d in the equation [1] is eliminated, the capacitance C is given by
[Equation 2]
C = ε ₀ · ε _r · S ² · E / {d ₀ · (S · E + F)}
However, since E: Young's modulus F: Load d ₀ : Distance between electrodes when no load is applied, the capacitance C actually measured when the load is applied to the capacitance load meter [number 2] The load F can be derived by substituting it into the equation.

  By the way, the dielectric constant of the dielectric 1 changes depending on the temperature, and the change of the dielectric constant of the dielectric 1 varies depending on the material. For example, polyphenyl sulfide (PPS) used as the material of the dielectric 1 is used. ) And polyethylene terephthalate (PET), there is a difference as shown in FIG.

  The capacitance C is a function of dielectric constant and has temperature dependence, as is apparent from the equation [2]. Therefore, when the ambient temperature changes, the accurate capacitance C, that is, the load F is measured. become unable.

  For this reason, conventionally, a temperature sensor is installed to measure the ambient temperature, a dielectric constant is obtained based on the measured ambient temperature, and the formula [2] is calculated from the dielectric constant and the measured capacitance. An electrostatic capacity type load cell has been developed in which the load is calculated using the. (For example, refer to Patent Document 1.)

  Also, a temperature-dependent capacitor is installed at a position where no load is applied, and the temperature is obtained from the dielectric constant by measuring the capacitance of the capacitor. In some cases, the dielectric constant of the dielectric 1 in the meter is obtained, and the load is obtained from the dielectric constant and the measured capacitance using the formula [2]. (For example, see Patent Document 2.)

Furthermore, a structure in which dielectrics 1 having opposite temperature characteristics are laminated, that is, a dielectric 1 whose dielectric constant increases with a rise in temperature and a dielectric 1 whose dielectric constant decreases with a rise in temperature. There is also a structure in which temperature dependence is offset by adopting a laminated structure. (For example, refer to Patent Document 3.)
JP 2001-13025 A JP 60-201230 A Japanese Patent Laid-Open No. 7-55615

  However, as described above, when the temperature is measured using a temperature sensor or a reference capacitor, the temperature of the dielectric 1 is set at a position where no load is applied to the temperature sensor, that is, outside or around the capacitive load meter. Could not be measured accurately.

  In addition, since the temperature sensor and the reference capacitor protrude outside the capacitive load cell, it is difficult to achieve a compact size.

  Furthermore, if the structure in which the dielectrics 1 having opposite temperature characteristics are laminated is employed, the material of the dielectrics 1 is limited, and the selection thereof is difficult.

  In view of such circumstances, the present invention can increase the load measurement accuracy without being affected by changes in the ambient temperature, can be made compact, and can easily select a dielectric material. It is an object of the present invention to provide a capacitive load cell to obtain.

The present invention relates to a capacitive load cell in which electrodes are arranged opposite to each other with a dielectric interposed therebetween.
Dielectric materials with different temperature characteristics are stacked between electrodes, the capacitance of each dielectric is measured, multiple expressions of capacitance given as a function of load, and multiple dielectric constants given as a function of temperature The present invention relates to a capacitance type load cell that is configured to obtain a load by simultaneously solving the above equation.

In the capacitance type load cell, a plurality of expressions of capacitance given as a function of load are
[Equation 3]
C ₁ = ε ₀ · ε ₁ · S ² · E ₁ / {d ₀ · (S · E ₁ + F)}
[Equation 4]
C ₂ = ε ₀ · ε ₂ · S ² · E ₂ / {d ₀ · (S · E ₂ + F)}
C ₁ : capacitance of the first dielectric C ₂ : capacitance of the second dielectric ε ₀ : dielectric constant of vacuum ε ₁ : relative dielectric constant of the first dielectric ε ₂ : second S: Dielectric area E ₁ : Young's modulus of the first dielectric E ₂ : Young's modulus of the second dielectric F: Load d ₀ : Distance between electrodes at no load, Several equations for permittivity given as a function of temperature are
[Equation 5]
ε ₁ = f ₁ (T)
[Equation 6]
ε ₂ = f ₂ (T)
And the unknowns can be F, ε ₁ , ε ₂ , T.

The present invention also relates to a capacitance type load cell in which electrodes are arranged opposite to each other with a dielectric interposed therebetween.
A structure in which dielectrics with different areas are sandwiched between electrodes, the capacitance of each dielectric is measured, and the load is obtained by simultaneously solving multiple equations of capacitance given as a function of the load. The present invention relates to a capacitance type load cell.

In the capacitance type load cell, a plurality of expressions of capacitance given as a function of load are
[Equation 7]
C ₁ = ε ₀ · ε · S ₁ ² · E / {d ₀ · (S ₁ · E + F)}
[Equation 8]
C ₂ = ε ₀ · ε · S ₂ ² · E / {d ₀ · (S ₂ · E + F)}
Where C ₁ is the capacitance of the first dielectric C _{2 is the} capacitance of the second dielectric ε _{0 is} the dielectric constant of the vacuum ε is the relative dielectric constant of the first dielectric and the second dielectric S ₁ : Area of the first dielectric S ₂ : Area of the second dielectric E: Young's modulus of the first dielectric and the second dielectric F: Load d ₀ : Distance between electrodes at no load Yes, the unknowns can be F and ε.

Furthermore, the present invention relates to a capacitive load meter in which electrodes are arranged opposite to each other with a dielectric interposed therebetween.
The dielectric is sandwiched between electrodes, the capacitance of each dielectric is measured at different frequencies, and the capacitance obtained as a function of the load is obtained because the dielectric constant changes due to different measurement frequencies. The present invention relates to a capacitive load meter that is configured to obtain a load by simultaneously solving a plurality of equations.

In the capacitance type load cell, there are a plurality of expressions of capacitance obtained as a function of the load obtained because the dielectric constant changes due to different measurement frequencies.
[Equation 9]
C ₁ = ε ₀ · ε ₁ · S ² · E / {d ₀ · (S · E + F)}
[Equation 10]
C ₂ = ε ₀ · ε ₂ · S ² · E / {d ₀ · (S · E + F)}
C ₁ : capacitance of the first dielectric C ₂ : capacitance of the second dielectric ε ₀ : dielectric constant of vacuum ε ₁ : relative dielectric constant of the first dielectric ε ₂ : second S: Area of first dielectric and second dielectric E: Young's modulus of first dielectric and second dielectric F: Load d ₀ : Between no-load electrodes It is the distance, and the ratio of the relative dielectric constant is calculated from the equations [9] and [10].
[Equation 11]
ε ₁ / ε ₂ = C ₁ / C ₂
The temperature is obtained based on the ratio of the relative permittivity, and at least one of the relative permittivity of the first dielectric and the relative permittivity of the second dielectric is determined from the temperature. Using at least one of the relative permittivity of the dielectric and the relative permittivity of the second dielectric, the load as an unknown can be calculated from at least one of the formula [9] and the formula [10]. it can.

  In the capacitance type load cell, when the load calculated from the [Equation 9] and the load calculated from the [Equation 10] are different, the average of both can be calculated as the load.

  According to the above means, the following operation can be obtained.

  When a load is applied to the capacitance type load cell, the capacitance of each laminated dielectric is measured, and various formulas related to the capacitance are solved simultaneously. Unlike temperature measurement using a temperature sensor or a reference capacitor installed outside or around a capacitive load cell, the load is accurately obtained without directly measuring the temperature.

  In addition, structurally, it is only necessary to sandwich the dielectric between the electrodes, and the conventional temperature sensor and reference capacitor need not be installed outside or around the capacitive load cell. Since it does not protrude outside the capacitive load cell, it can be made compact.

  Furthermore, compared to adopting a structure in which dielectrics having opposite temperature characteristics are laminated, the dielectric material is not limited and the selection thereof is facilitated.

  According to the capacitive load cell of the first to seventh aspects of the present invention, the load measurement accuracy can be enhanced without being affected by the change in the ambient temperature, and the size can be reduced. It is possible to achieve an excellent effect that the selection of the dielectric material can be easily performed.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 (a) and 1 (b) show a first example of an embodiment of the present invention. In the figure, parts denoted by the same reference numerals as those in FIG. The bodies 1 and 4 are sandwiched between the electrodes 2 and 3 and the electrodes 3 and 5, the capacitances of the dielectrics 1 and 4 are measured, and a plurality of expressions of capacitance given as a function of the load and the temperature The load is obtained by simultaneously solving a plurality of equations of permittivity given as a function of.

The equations for capacitance given as a function of the load are:
[Equation 12]
C ₁ = ε ₀ · ε ₁ · S ² · E ₁ / {d ₀ · (S · E ₁ + F)}
[Equation 13]
C ₂ = ε ₀ · ε ₂ · S ² · E ₂ / {d ₀ · (S · E ₂ + F)}
However, C ₁ : Capacitance in the first dielectric 1 C ₂ : Capacitance in the second dielectric 4 ε ₀ : Dielectric constant of vacuum ε ₁ : Relative permittivity of the first dielectric 1 ε ₂ : Relative dielectric constant of second dielectric 4 S: area of dielectrics 1 and 4 E ₁ : Young's modulus of first dielectric 1 E ₂ : Young's modulus of second dielectric 4 F: load d ₀ : The distance between the electrodes 2 and 3 at no load and the distance between the electrodes 3 and 5 at no load, and a plurality of expressions of dielectric constant given as a function of temperature are
[Equation 14]
ε ₁ = f ₁ (T)
[Equation 15]
ε ₂ = f ₂ (T)
And the unknowns are F, ε ₁ , ε ₂ , T.

  For example, a resin film such as polyphenyl sulfide (PPS) is used as the material of the dielectric 1, and a resin film such as polyethylene terephthalate (PET) is used as the material of the dielectric 4. The electrodes 2 and 3 and the electrodes 3 and 5 are formed on the surfaces of the dielectrics 1 and 4 by vapor deposition. Examples of the material include gold (Au), chromium (Cr), and chromium-nickel (Cr -Ni) or the like can be used.

  Next, the operation of the illustrated example will be described.

At the time of applying a load to the capacitance type load cell, the capacitances C ₁ and C ₂ of the laminated dielectrics 1 and 4 are measured, and [Equation 12] related to the capacitances C ₁ and C ₂ The following four equations, [Equation 13], [Equation 14], and [Equation 15] are solved simultaneously, and are thus installed outside or around the capacitance load meter as in the past. Unlike measuring a temperature using a temperature sensor or a reference capacitor, the load F can be accurately obtained without directly measuring the temperature.

  In addition, structurally, the dielectrics 1 and 4 need only be sandwiched between the electrodes 2 and 3 and the electrodes 3 and 5, and the temperature sensor and the reference capacitor that have been required in the past have a capacitive load. Since it does not need to be installed outside or around the meter and does not protrude outside the capacitance type load cell, it is possible to reduce the size.

  Furthermore, the material of the dielectrics 1 and 4 is not limited as compared with the case where a structure in which dielectrics having opposite temperature characteristics are stacked is employed, and the selection thereof becomes easy.

  Thus, the load measurement accuracy can be improved without being affected by changes in the ambient temperature, the size can be reduced, and the materials for the dielectrics 1 and 4 can be easily selected.

  In the first example shown in FIGS. 1 (a) and 1 (b), the electrode 3 is commonly used as an electrode sandwiching the dielectrics 1 and 4, but the electrode 3 is divided into two pieces and an insulator is provided between them. Needless to say, it may be possible to intervene.

  2 (a) and 2 (b) show a second embodiment of the present invention. In the figure, the same reference numerals as those in FIGS. 1 (a) and 1 (b) denote the same items. The dielectrics 1 and 6 having different areas are sandwiched between the electrodes 2 and 3 and the electrodes 3 'and 5 and the capacitances of the dielectrics 1 and 6 are measured and given as a function of the load. The load is obtained by simultaneously solving a plurality of equations.

The equations for capacitance given as a function of the load are:
[Equation 16]
C ₁ = ε ₀ · ε · S ₁ ² · E / {d ₀ · (S ₁ · E + F)}
[Equation 17]
C ₂ = ε ₀ · ε · S ₂ ² · E / {d ₀ · (S ₂ · E + F)}
However, C ₁ : Capacitance in the first dielectric 1 C ₂ : Capacitance in the second dielectric 6 ε ₀ : Dielectric constant of vacuum ε: First dielectric 1 and second dielectric 6 Relative dielectric constant S ₁ : area of the first dielectric 1 S ₂ : area of the second dielectric 6 E: Young's modulus of the first dielectric 1 and the second dielectric 6 F: load d ₀ : The distance between the electrodes 2 and 3 when there is no load and the distance between the electrodes 3 'and 5 when there is no load, and the unknowns are F and ε.

  The dielectrics 1 and 6 are made of the same material, and as the material, for example, a resin film such as polyphenyl sulfide (PPS) or polyethylene terephthalate (PET) can be used, and the electrodes 2, 3 and The electrodes 3 ′ and 5 are formed on the surfaces of the dielectrics 1 and 4 by vapor deposition, and as the material thereof, for example, gold (Au), chromium (Cr), chromium-nickel (Cr—Ni), or the like is used. it can.

  In addition, in the second example shown in FIGS. 2A and 2B, the attachments 7 and 9 made of an insulator such as an acrylic plate are arranged so as to cover the outer surfaces of the electrodes 2 and 5, and the electrodes 3 and 3 ′. An attachment 8 made of an insulator such as an acrylic plate is interposed therebetween.

In the second example shown in FIGS. 2A and 2B, the capacitances C ₁ and C ₂ of the stacked dielectrics 1 and 6 are measured when a load is applied to the capacitance type load cell. The _two equations, [Equation 16] and [Equation 17], related to the capacitances C ₁ and C ₂ are solved simultaneously. Unlike measuring the temperature using a temperature sensor or a reference capacitor installed in the vicinity, the load F can be obtained with high accuracy without directly measuring the temperature.

  In addition, structurally, the dielectrics 1 and 6 need only be stacked with the electrodes 2 and 3 and the electrodes 3 'and 5 sandwiched therebetween, and the conventionally required temperature sensor and reference capacitor are capacitive type. Since it does not need to be installed outside or around the load cell and does not protrude outside the capacitance load cell, it is possible to achieve compactness.

  Furthermore, the material of the dielectrics 1 and 6 is not limited as compared with the case where a structure in which dielectrics having opposite temperature characteristics are stacked is employed, and the selection thereof is facilitated.

  Thus, in the case of the second example shown in FIGS. 2 (a) and 2 (b), the load measurement accuracy can be improved without being affected by changes in the ambient temperature, and the size can be reduced. The material for the bodies 1 and 6 can be easily selected.

3 (a) and 3 (b) show a third example of the embodiment of the present invention. In the figure, the same reference numerals as those in FIGS. 2 (a) and 2 (b) denote the same items. The dielectrics 1 and 10 are stacked between the electrodes 2 and 3 and the electrodes 3 'and 5 and the capacitances of the dielectrics 1 and 10 are measured at different frequencies fr ₁ and fr ₂ , and the measurement frequency fr _{1 is} measured. , Fr ₂ , and the dielectric constant changes due to the difference, and the load is obtained by simultaneously solving a plurality of expressions of the capacitance given as a function of the load.

A plurality of expressions of capacitance obtained as a function of load obtained because the dielectric constant changes due to the difference between the measurement frequencies fr ₁ and fr ₂ are as follows:
[Equation 18]
C ₁ = ε ₀ · ε ₁ · S ² · E / {d ₀ · (S · E + F)}
[Equation 19]
C ₂ = ε ₀ · ε ₂ · S ² · E / {d ₀ · (S · E + F)}
C ₁ : capacitance of the first dielectric 1 C ₂ : capacitance of the second dielectric 10 ε ₀ : dielectric constant of vacuum ε ₁ : relative dielectric constant of the first dielectric 1 ε ₂ : Relative dielectric constant of second dielectric 10 S: area of first dielectric 1 and second dielectric 10 E: Young's modulus of first dielectric 1 and second dielectric 10 F: load d ₀ : distance between electrodes 2 and 3 when no load and distance between electrodes 3 ′ and 5 when no load is applied, and the ratio of the relative permittivity is calculated from the equations [18] and [19].
[Equation 20]
ε ₁ / ε ₂ = C ₁ / C ₂
The temperature is obtained based on the relative dielectric constant ratio ε ₁ / ε _2, and the relative dielectric constant ε ₁ of the _first dielectric ₁ and the relative dielectric constant ε _{2 of} the second dielectric 10 are calculated from the temperature. And at least one of the relative dielectric constant ε ₁ of the _first dielectric ₁ and the relative dielectric constant ε ₂ of the _second dielectric 10 is used to obtain the equation [Equation 18] and [Equation 19]. ] The load F as an unknown is calculated from at least one of the equations.

Here, when the dielectrics 1 and 10 are made of the same material, for example, a resin film such as polyphenyl sulfide (PPS) is used, even if the dielectrics 1 and 10 are made of the same material, as shown in FIG. Since the dielectric constants (relative dielectric constants ε ₁ , ε ₂ ) are changed by different fr ₁ (= 1 [kHz]) and fr ₂ (= 100 [kHz]), if the ratio of the dielectric constants is known, And the dielectric constant (relative dielectric constants ε ₁ and ε ₂ ) can be obtained from the data shown in FIG.

  It should be noted that the load F calculated from the above [Equation 18] and the load F calculated from the [Equation 19] do not necessarily coincide with each other, and a slight error may occur. When the load F calculated from the equation [19] and the load F calculated from the equation [19] are different, the average of both may be calculated as the load F.

In the third example shown in FIGS. 3A and 3B, when the load is applied to the capacitive load cell, the frequencies of the capacitances C ₁ and C _{2 in} the laminated dielectrics 1 and 10 are different. The relative dielectric constant ratio ε ₁ / ε ₂ is calculated from the two equations, [Equation 18] and [Equation 19], which are measured by fr ₁ and fr ₂ and related to the capacitances C ₁ and C _2. 20], the temperature is obtained from the data of FIG. 4 based on the ratio ε ₁ / ε ₂ of the relative permittivity, and the relative permittivity ε ₁ of the _first dielectric ₁ and the second are determined from the temperature. of at least one of the dielectric constant epsilon ₂ of the dielectric 10 is determined, at least one of the dielectric constant of the first dielectric 1 epsilon ₁ and the dielectric constant epsilon ₂ of the second dielectric 10 Is used to calculate the load F as an unknown number from at least one of the [Expression 18] and the [Expression 19]. Unlike measuring the temperature using a temperature sensor or a reference capacitor installed outside or around the load cell, the load F can be accurately obtained without directly measuring the temperature.

  Moreover, structurally, it is only necessary to laminate the dielectrics 1 and 10 between the electrodes 2 and 3 and the electrodes 3 'and 5, and a temperature sensor and a reference capacitor which have been conventionally required are electrostatic capacitance type. Since it does not need to be installed outside or around the load cell and does not protrude outside the capacitance load cell, it is possible to achieve compactness.

  Furthermore, the material of the dielectrics 1 and 10 is not limited as compared with the case where a structure in which dielectrics having opposite temperature characteristics are stacked is employed, and the selection thereof becomes easy.

  Thus, in the case of the third example shown in FIGS. 3A and 3B, the load measurement accuracy can be improved without being affected by the change in the ambient temperature, the size can be reduced, and the dielectric can be further reduced. The material for the bodies 1 and 10 can be easily selected.

  The capacitance load meter of the present invention is not limited to the illustrated example described above, and it is needless to say that various changes can be made without departing from the gist of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the 1st example of embodiment which implements this invention, Comprising: (a) is a side view, (b) is a top view. It is a schematic block diagram of the 2nd example of embodiment which implements this invention, Comprising: (a) is a side view, (b) is a top view. It is a general | schematic block diagram of the 3rd example of embodiment which implements this invention, Comprising: (a) is a side view, (b) is a top view. It is a diagram which shows an example of the difference in the temperature characteristic of the dielectric constant by the measurement frequency of a dielectric material. It is a perspective view which shows an example of an electrostatic capacitance type load meter. It is a diagram which shows an example of the difference in the temperature characteristic of the dielectric constant by the material of a dielectric material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dielectric 2 electrode 3 Electrode 3 'electrode 4 Dielectric 5 Electrode 6 Dielectric 7 Attachment 8 Attachment 9 Attachment 10 Dielectric fr ₁ frequency fr ₂ frequency

Claims (7)

In a capacitance type load cell in which electrodes are arranged facing each other across a dielectric,
Dielectric materials with different temperature characteristics are stacked between electrodes, the capacitance of each dielectric is measured, multiple expressions of capacitance given as a function of load, and multiple dielectric constants given as a function of temperature A capacitance type load cell that is configured to obtain a load by simultaneously solving the above equation. Several equations of capacitance given as a function of load are
[Equation 1]
C ₁ = ε ₀ · ε ₁ · S ² · E ₁ / {d ₀ · (S · E ₁ + F)}
[Equation 2]
C ₂ = ε ₀ · ε ₂ · S ² · E ₂ / {d ₀ · (S · E ₂ + F)}
C ₁ : capacitance of the first dielectric C ₂ : capacitance of the second dielectric ε ₀ : dielectric constant of vacuum ε ₁ : relative dielectric constant of the first dielectric ε ₂ : second S: Dielectric area E ₁ : Young's modulus of the first dielectric E ₂ : Young's modulus of the second dielectric F: Load d ₀ : Distance between electrodes at no load, Several equations for permittivity given as a function of temperature are
[Equation 3]
ε ₁ = f ₁ (T)
[Equation 4]
ε ₂ = f ₂ (T)
The capacitance load meter according to claim ₁ , wherein the unknowns are F, ε ₁ , ε ₂ , and T. In a capacitance type load cell in which electrodes are arranged facing each other across a dielectric,
A structure in which dielectrics with different areas are sandwiched between electrodes, the capacitance of each dielectric is measured, and the load is obtained by simultaneously solving multiple equations of capacitance given as a function of the load. Capacitance type load cell characterized by that. Several equations of capacitance given as a function of load are
[Equation 5]
C ₁ = ε ₀ · ε · S ₁ ² · E / {d ₀ · (S ₁ · E + F)}
[Equation 6]
C ₂ = ε ₀ · ε · S ₂ ² · E / {d ₀ · (S ₂ · E + F)}
Where C ₁ is the capacitance of the first dielectric C _{2 is the} capacitance of the second dielectric ε _{0 is} the dielectric constant of the vacuum ε is the relative dielectric constant of the first dielectric and the second dielectric S ₁ : Area of the first dielectric S ₂ : Area of the second dielectric E: Young's modulus of the first dielectric and the second dielectric F: Load d ₀ : Distance between electrodes at no load The capacitance load meter according to claim 3, wherein the unknown number is F or ε. In a capacitance type load cell in which electrodes are arranged facing each other across a dielectric,
The dielectric is sandwiched between electrodes, the capacitance of each dielectric is measured at different frequencies, and the capacitance obtained as a function of the load is obtained because the dielectric constant changes due to different measurement frequencies. A capacitance-type load cell configured to obtain a load by simultaneously solving a plurality of equations. There are several equations for the capacitance obtained as a function of the load, which is obtained because the dielectric constant changes due to different measurement frequencies.
[Equation 7]
C ₁ = ε ₀ · ε ₁ · S ² · E / {d ₀ · (S · E + F)}
[Equation 8]
C ₂ = ε ₀ · ε ₂ · S ² · E / {d ₀ · (S · E + F)}
C ₁ : capacitance of the first dielectric C ₂ : capacitance of the second dielectric ε ₀ : dielectric constant of vacuum ε ₁ : relative dielectric constant of the first dielectric ε ₂ : second S: Area of first dielectric and second dielectric E: Young's modulus of first dielectric and second dielectric F: Load d ₀ : Between no-load electrodes It is the distance, and the ratio of the relative permittivity is calculated from the equations [7] and [8].
[Equation 9]
ε ₁ / ε ₂ = C ₁ / C ₂
The temperature is obtained based on the ratio of the relative permittivity, and at least one of the relative permittivity of the first dielectric and the relative permittivity of the second dielectric is determined from the temperature. The load as an unknown number is calculated from at least one of [Expression 7] and [Expression 8] using at least one of the relative permittivity of the dielectric and the relative permittivity of the second dielectric. 5. The capacitive load cell according to 5.   The capacitance type load cell according to claim 6, wherein when the load calculated from the formula [7] and the load calculated from the formula [8] are different, an average of both is calculated as a load.

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