Capacitance measuring device, capacity-type flat sensor device and capacity-type liquid level detection device

Abstract

Capacity measuring device (160, 630), comprising: Input voltage application device for applying a constant voltage input voltage to one of the opposite end sides of a capacitance (Cn) of a device under test; a bridging capacitor (12) which is connected in series with another of the opposite end faces of the device capacitance (Cn) and connects the other of the opposite end faces of the device capacitance (Cn) to a ground potential between the two; a charging / discharging switching element (SW10) which is connected in series with the other of the opposite end sides of the device capacitance (Cn) and in parallel with the bridging capacitor (12), whereby a charge at the other of the opposite end sides of the device capacitance (Cn) is discharged to the ground potential during a closed state of this; a control or regulation (13) that performs the following steps: a step of setting the input voltage application device to a state in which the input voltage is not applied, and setting the charge / discharge switching element (SW10) to the closed state thereof, thereby discharging the charge at the device capacitance (Cn) to the ground potential; and a step of setting the charging / discharging switching element (SW10) to an open state and setting the input voltage application device to a state in which the input voltage is applied, after the discharge step, thereby charging the measured object capacitance (Cn); and a measuring device (14) for determining an equivalent value for the capacitance of the object being measured (Cn) based on a potential between the capacitance of the object being measured (Cn) and the bridging capacitor (12) in the charging step carried out by the control or regulation (13).

Description

Technical field

[0001] The present invention relates to a capacitance measuring device, a capacitance-type flat sensor device, and a capacitance-type liquid level detector device that use the measuring device. background

[0002] A device that assesses whether a change in a measured capacity occurs as a result of an event originating from an object to be detected is described in international publication No. 2011 / 004727 (patent document No. 1).The device is equipped with a first switch that connects a reference capacitance "Cs" in series with respect to a capacitance "Cx1" to be measured to a first potential source "V1" on its own side, wherein one of the opposite ends of this switch is placed between the opposite ends of the reference capacitance connected to the first potential source "V1"; a second switch, one of the opposite ends of which is placed between another of the opposite ends of the capacitance to be measured, connected to a second potential source or free space, and another of the opposite ends of the reference capacitance; and a third switch, which is placed between the opposite ends of the capacitance to be measured.

[0003] Furthermore, the number of repetitions required until the potential between the terminals of the reference capacitance "Cs" changes to a setup potential "Vref" is counted when an operation to set the second switch to the closed state and another operation to set the third switch to the closed state are repeated alternately after an initial switching operation that sets the first switch to the closed state and then to the open state. Additionally, whether a change in the capacitance being measured is caused by an event originating from a measured object is assessed based on the respective number of repetitions ("N1", "N2") with varying times for executing the second switching operation.

[0004] Furthermore, the publication of the unexamined Japanese patent (KOKAI), Official Gazette No. 2005-30901 (Patent Publication No. 2), describes the arrangement of electrodes in multiple rows and those in multiple columns for measuring the respective capacitances at the matrix-arranged measurement object positions. The device measures the capacitances by measuring a current flowing to one of the capacitances at the measurement object positions while outputting a pulsating signal to another of the capacitances there.

[0005] Furthermore, measuring devices for capacitance are described in Japanese Patent Gazette No. 3379388 (Patent Publication No. 3), in Japanese Patent, Official Gazette No. 2561040 (Patent Publication No. 4), in International Publication No. 2011 / 125725 (Patent Publication No. 5), and similar publications. Additionally, devices that use capacitance to detect liquid levels are described in the publication of the unexamined Japanese patent (KOKAI), Official Gazette No. 11-311562 (Patent Publication No. 6), and in the publication of the unexamined Japanese patent (KOKAI), Official Gazette No. 2006-337173 (Patent Publication No. 7).

[0006] The JP S48 - 31 979 A describes a capacitance measurement method suitable for determining the capacitance, thickness and permittivity of a thin film.

[0007] DE 102 31 153 A1 describes a method in which a first and second predetermined charging voltage are applied between the movable and fixed electrodes of a capacitive sensor to measure the first and second capacitances between the movable and fixed electrodes, respectively. The first and second electrostatic capacitances are compared to obtain a characteristic of the sensor from the result of the comparison. When measuring the first and second capacitances, first and second charging voltages are generated, the magnitudes of which are determined according to the first and second capacitances, respectively.A balance is achieved between the first output voltage, when the first charging voltage is applied between the moving and fixed electrodes in a predetermined normal state of the moving electrode, and the second output voltage, which is output when the second charging voltage is applied between the moving and fixed electrodes in a predetermined normal state. Technical literature and patent literature used Patent Publication No. 1: WO 2011 / 004 727 A1 Patent Publication No. 2: JP 2005 - 30 901 A Patent document No. 3: JP 3 379 388 B2 Patent document No. 4: JP 2 561 040 B2 Patent Publication No. 5: WO 2011 / 125 725 A1; Patent Publication No. 6: JP H11 - 311 562 A Patent Publication No. 7: JP 2006 - 337 173 A Summary of the invention; Problems to be solved by the invention

[0008] It was previously known that capacitance is measured by measuring the current flowing to one side of the capacitor opposite the other when an alternating voltage is applied to the opposite side. However, when measuring capacitance based on such a current value, the capacitance cannot be measured with high accuracy due to the fact that the current value is small and therefore affected by noise.

[0009] Furthermore, in a case where another predetermined capacitor is connected in series with the capacitor of the object under test, and a constant voltage is then applied to it, it is conceivable to calculate the capacitance of the object by measuring a potential between the capacitors. This means that the object of test in this case is not a current value, but a voltage value. However, since the potential between the two capacitors is indeterminate, the capacitance measured using the potential between the capacitors is not highly accurate. Moreover, the conventional techniques described above lead to very complex measuring devices.

[0010] Furthermore, with the device described in patent document no. 5, it is not easy to measure a test object's capacitance at a high speed or rate due to the fact that it takes a certain amount of time for electricity to be stored in the capacitor "C1".

[0011] An object of the present invention is to enable, as desired, a higher speed or rate of measurement and improved noise resistance by employing a method for measuring a potential between a capacitor and a further predetermined capacitor, wherein the former represents a test object and the latter is connected in series with the former; and furthermore, by providing a capacitance measuring device that can measure the test object capacitance with high accuracy, even when measuring a potential between the capacitors.

[0012] Furthermore, a further objective is to provide a capacitance-type flat sensor device and a capacitance-type liquid level detector device that utilize the measuring device. In particular, a further objective is to provide a capacitance-type flat sensor device and a capacitance-type liquid level detector device that can measure the capacitance of a target object with a high rate and high accuracy. Means to solve the problem: Capacity measuring device

[0013] In connection with the present invention, the following has been found: Selecting a state in which a potential between two capacitors is discharged to a ground potential as a reference state makes it possible to measure a measured object capacitance by measuring the potential between the two capacitors.

[0014] In particular, a capacity measuring device that relies on one of the present means includes: an input voltage application device for applying a constant voltage input voltage to one of the opposite end faces of a capacitance of a device under test; a capacitor for bridging, wherein the capacitor is connected in series with another of the opposite end faces of the device capacitance and connects the other of the opposite end faces of the device capacitance to a ground potential between the two; a charging / discharging switching element connected in series with the other of the opposite end faces of the device capacitance and connected in parallel with the bypass capacitor, whereby a charge at the other of the opposite end faces of the device capacitance is discharged to ground potential during a closed state; a control system or regulation that performs the following steps: a step of setting the input voltage application device to a state in which the input voltage is not applied, and setting the charge / discharge switching element to a closed state thereof, thereby discharging the charge at the device capacitance to the ground potential; and a step of setting the charging / discharging switching element to an open state and setting the input voltage application device to a state in which the input voltage is applied, after the discharge step, thereby charging the device capacitance; and a measuring device for determining an equivalent value for the capacitance of the object being measured based on a potential between the capacitance of the object being measured and the bridging capacitor in the charging step, with execution by the control or regulation.

[0015] The bypass capacitor is connected in series with the capacitance of the device under test, and the measuring device determines an equivalent value for the capacitance based on the potential (or an intermediate potential) between the capacitance of the device under test and the bypass capacitor, that is, a potential at the other of the opposite ends of the capacitance of the device under test. Note that because an intermediate potential between the two capacitors is indeterminate, the capacitance measured using the intermediate potential is not highly accurate.

[0016] However, setting the charge / discharge switch to the closed position leads to a discharge of the charge at the device under test. Specifically, the aforementioned intermediate potential becomes a ground potential. This state is chosen as the reference state. This means that the intermediate potential in the reference state is equal to the ground potential. In other words, it is possible to calibrate the intermediate potential by setting the charge / discharge switch to the closed position.

[0017] Furthermore, the measuring device measures a potential at the opposite end of the capacitance under test when the charge / discharge switch is set to the open state and the input voltage is set to a state after the charge has been discharged from the capacitance under test. This means that the potential measured by the measuring device is a potential that coincides with the capacitance under test. Therefore, the measuring device can measure the capacitance of the object under test with a high degree of accuracy.

[0018] Furthermore, since the aforementioned method is a technique for measuring capacitance using the intermediate potential, interference from noise is less likely compared to current measurement, thus enabling highly accurate capacitance measurement. Additionally, the fact that the measurement is performed using the intermediate potential allows for high-rate or high-speed measurement. It is also possible to perform a calibration, in which the charge / discharge switching element is in the closed state, within a short timeframe. For this reason as well, high-rate or high-speed capacitance measurement is possible overall.

[0019] The following are explanations of some suitable modes of the capacitance measuring device that refer to the present means.

[0020] The input voltage application device may preferably include: a constant voltage power source with the ability to apply the input voltage; and a first input switching element, which is connected at one of the opposite end sides of this to one of the opposite end sides of the device capacitance, and at the other of the opposite end sides of this to one of the constant voltage power sources and the ground potential, and switches back and forth between a state in which the constant voltage power source applies the input voltage to the device capacitance and another state in which the constant voltage power source does not apply the input voltage to the device capacitance.

[0021] This allows the intermediate potential to be reliably converted to the reference state potential, and the state of the input voltage being applied to the capacitance of the object under test can be reliably established. As a result, a highly accurate equivalent value for the capacitance can be determined.

[0022] Furthermore, the capacitance measuring device may preferably comprise: a second capacitor having an opposite end side to which a second constant voltage input voltage is applied, and another opposite end side connected to the other of the opposite end sides of the capacitance of the object under test.

[0023] This allows for the determination of an equivalent value with higher accuracy for the measurement object capacity.

[0024] Furthermore, the capacitance measuring device can preferably switch between states of this in the following sequence: a first state in which neither the input voltage nor the second input voltage is applied; a second state in which one input voltage and the second input voltage are applied, but the other is not applied; a third state in which both are supplied by the first input voltage and the second input voltage; and a fourth state in which one of the input voltages is not applied and the second input voltage is not applied, but the other is applied; wherein the measuring device determines an equivalent value for the object capacitance based on a potential at the other of the opposite end faces of the object capacitance in the second state, the third state or the fourth state.

[0025] This allows an equivalent value for the measurement object capacity to be determined with much higher accuracy.

[0026] Furthermore, the capacitance of the bridging capacitor is preferably chosen to be larger than the capacitance between the ground potential and the other of the opposite end faces of the device under test.

[0027] This reliably reduces the extent of the capacitance impairment that exists between the ground potential and the other of the opposite ends of the device capacitance. Therefore, an equivalent value for the device capacitance can be determined with much higher accuracy.

[0028] Furthermore, the capacitance measuring device is preferably able to determine each of the equivalent values ​​for several object capacitances in a sensor body; and an equivalent circuit of the sensor body may include: several rows of first electrodes, several columns of second electrodes for placement such that these form a matrix shape with the first electrodes arranged in several rows, and several dielectric layers arranged at several positions where the first electrodes arranged in several rows and the second electrodes arranged in several columns intersect each other three-dimensionally; where the equivalent values ​​for the multiple object capacitances in the sensor body are equivalent values ​​for capacitances between the first electrodes and the second electrodes, corresponding to the respective positions in the multiple dielectric layers.

[0029] This means that in the equivalent circuit, the multiple capacitances under test are arranged in a matrix. Furthermore, the use of the previously described capacitance measuring device allows for highly accurate determination of each of the equivalent values ​​for each of the matrix-arranged capacitances under test.

[0030] Furthermore, the measuring device should preferably be able to solve simultaneous equations, which can be expressed as follows: respective voltages at the second electrodes, which are selected when the input voltage is applied to one of the first electrodes of the first electrodes arranged in multiple rows and the other remaining first electrodes are connected to ground potential; and Capacities that serve as unknown quantities and occur at multiple positions where the selected second electrodes intersect each of the first electrodes arranged in multiple rows in three dimensions; whereby the measuring device determines equivalent values ​​for the respective capacitances, which serve as unknown quantities, in the simultaneous equations.

[0031] When measuring a potential at the opposite end of one of the capacitances being measured, a situation may arise where the measurement is affected by the other capacitances. Therefore, as described above, the measuring device solves the simultaneous equations in which the multiple capacitances serve as unknown quantities and which are expressed in terms of the respective capacitances and the capacitances influencing them. Consequently, the equivalent values ​​for the respective capacitances used as unknown quantities in the simultaneous equations can be determined with a high degree of accuracy. Capacitive flat sensor device

[0032] Next, explanations will follow regarding a capacitance-type flat sensor device that uses the previously described capacitance measuring device.

[0033] A capacitance-type flat sensor device based on the present means comprises: First electrodes arranged in several rows, which are formed in strip form and placed alternately parallel to each other; Second electrodes arranged in several columns, which are formed in strip form and placed alternately parallel to each other, wherein the second electrodes arranged in several columns are arranged in opposite positions to the first electrodes arranged in several rows such that they are opposite to the first electrodes in order to form a matrix shape; a dielectric layer located between each of the first electrodes in the first electrodes arranged in multiple rows and each of the second electrodes in the second electrodes arranged in multiple columns; and the aforementioned capacitance measuring device for determining an equivalent value for a capacitance at each of the matrix-shaped positions corresponding to an opposite position of each of the first electrodes to each of the second electrodes; wherein the first electrodes form one of the opposite end faces of the device capacitance; and The second electrodes form the other of the opposite end faces of the object's capacitance.

[0034] The flat sensor device has several capacitances arranged in a matrix. In this case, using the capacitance measuring device described above allows for the highly accurate determination of an equivalent value for each of the matrix-arranged capacitances.

[0035] The following are explanations of some suitable modes of the capacitance-type flat sensor device, which is based on the present means.

[0036] The capacitance-type flat sensor device may preferably further comprise a third electrode, which is arranged such that it is on an opposite side to the second electrodes with respect to the first electrodes and is connected to the ground potential; and wherein a capacitor formed by the second electrodes and the third electrode forms the bridging capacitor.

[0037] The third electrode can be used as one of the opposite electrodes of the bridging capacitor. Therefore, the construction is simplified.

[0038] The capacitance-type flat sensor device may preferably further comprise: a third electrode arranged such that it is on an opposite side to the second electrodes with respect to the first electrodes; wherein the capacitance measuring device may further comprise a second capacitor having an opposite end face to which a second constant voltage input voltage is applied, and another opposite end face connected to the other of the opposite end faces of the capacitance of the object under test; and a capacitor formed by the second electrodes and the third electrode, forming the second capacitor.

[0039] Since the capacitor formed by the second electrodes and the third electrode constitutes the second capacitor, a dedicated or purpose-built capacitor becomes unnecessary. Capacity-type liquid level detector device

[0040] Next, an explanation of a capacitance-type liquid level sensor device will follow, which uses the previously described capacitance measuring device.

[0041] A capacitance-type liquid level sensor device based on the present means comprises: several electrodes, which are placed in a staggered manner in the vertical direction of this within a liquid-storing tank; the aforementioned capacitance measuring device for determining an equivalent value for a capacitance between two electrodes selected from among the several electrodes, as the equivalent value for the object capacitance; and an evaluation unit for evaluating a liquid level within the tank based on the equivalent value for the object capacitance.

[0042] The use of the aforementioned capacitance measuring device allows for the highly accurate determination of an equivalent value for each of the matrix-arranged measuring object capacitances. Therefore, the liquid level can be determined with high accuracy.

[0043] The following are explanations of some suitable modes of the capacitance-type liquid level detector device based on the present means.

[0044] The assessment unit can preferably assess liquid quality based on the equivalent value for the measuring object capacity.

[0045] This makes capacity a value that coincides with liquid quality. Therefore, the liquid quality within the tank must be determined with a high degree of accuracy.

[0046] The capacitance measuring device may further preferably comprise a second capacitor having an opposite end side to which a second constant voltage input voltage is applied, and another opposite end side which is connected to the other of the opposite end sides of the capacitance of the object being measured; wherein a capacitor formed by the two electrodes of the object being measured, one of which is located on a lower side and the other on a side even further below, forms the second capacitor; and The assessment unit assesses a boundary between different types of liquids based on the equivalent value for the measuring object capacity.

[0047] A comparison of the capacitances between electrodes that are adjacent to each other vertically leads to the conclusion that the same type of liquid is present if the capacitances coincide, and that distinguishable liquids are present if they differ. Therefore, if different types of liquids are present, the boundary between them can be determined with a high degree of accuracy. Brief description of the drawing Fig. Figure 1 shows a circuit diagram of a capacitance measuring device 10 according to a first embodiment. Fig. 2 is a timing diagram for the activation or operating processes of switching devices (SW10, SW11), a potential “Vin1” at one of the opposite end sides of a measured object capacitance “Cn” and an output voltage “Vout” in the first embodiment. Fig. Figure 3 shows a circuit diagram of a capacitance measuring device 20 according to a second embodiment. Fig. Figure 4 shows a circuit diagram of a capacitance measuring device 30 according to a third embodiment. Fig. 5 is a timing diagram for the activation or operating processes of switching devices (SW10, SW11, SW12), a potential “Vin1” at one of the opposite end sides of a measured object capacitance “Cn”, a potential “Vin2” at one of the opposite end sides of a second capacitor and an output voltage “Vout” in the third embodiment. Fig. Figure 6 shows a measuring circuit when SW10 is in the closed state (i.e., "ON") and SW11 and SW12 are connected to a ground potential. Fig. Figure 7 shows a measuring circuit when SW10 is in the open state (i.e., “OFF”), SW11 is connected to ground potential, and SW12 is connected to a power source. Fig. Figure 8 shows a measuring circuit when SW10 is in the open state (i.e., “OFF”) and SW11 and SW12 are connected to the power source. Fig. Figure 9 shows a measuring circuit when SW10 is in the open state (i.e., “OFF”), SW11 is connected to the power source, and SW12 is connected to ground potential. Fig. 10 is a timing diagram for the activation or operating processes of switching devices (SW10, SW11, SW12), a potential “Vin1” at one of the opposite end sides of a measured object capacitance “Cn”, a potential “Vin2” at one of the opposite end sides of a second capacitor and an output voltage “Vout” in the fourth embodiment. Fig. Figure 11 shows a structure of a capacitance-type flat sensor device 100 according to a first embodiment, wherein a sensor body 110 is shown in plan view. Fig. Figure 12 shows a further assembly of the capacitance-type flat sensor device 100 from the illustration in Fig. 11, where the sensor body 110 is shown in a cross-sectional view. Fig. 13 is a circuit diagram, if a part of the in Fig. 11 and in Fig. 12 of the sensor body shown is 110 removed from this. Fig. Figure 14 shows a complete measurement circuit when a capacitance at a measurement object position is labelled "C1". Fig. Figure 15 shows a circuit that works against the one in Fig. The measuring circuit shown in section 14 has been replaced. Fig. Figure 16 shows a structure of a capacitance-type flat sensor device 200 according to a second embodiment, wherein a sensor body 110 is shown in a cross-sectional view. Fig. 17 shows the measuring circuit of Fig. 16, if a capacitance at a measurement object position is designated “C1”. Fig. Figure 18 shows a measuring circuit in a capacitance-type flat sensor device 300 according to a third embodiment, where a capacitance at a measuring object position is designated by “C1”. Fig. Figure 19 shows capacity values ​​for the respective capacities “C1” to “C9” in a sequence to illustrate a capacity-type flat sensor device according to a fourth embodiment. Fig. Figure 20 is a graph to represent a difference between capacities that can be determined using a technique with simultaneous equations in the fourth embodiment and those that can be determined using a different technique with non-simultaneous equations. Fig. Figure 21 shows a structure of a capacitance-type liquid level detector device 600 according to a first embodiment. Fig. Figure 22 shows a detailed structure of a sensor body 621, which is located in Fig. 21 is shown. Fig. Figure 23 shows an equivalent circuit for the sensor body 621 according to the first embodiment. Fig. Figure 24 shows a circuit diagram of the capacitance-type liquid level detector device 600 according to the first embodiment. Fig. Figure 25 shows a detailed structure of a sensor body 721 of a capacitance-type liquid level detector device 700 according to a second embodiment. Fig. Figure 26 shows a circuit diagram of the capacitance-type liquid level detector device 700 according to the second embodiment. Fig. Figure 27 shows a detailed structure of a sensor body 721 of a capacitance-type liquid level detector device 800 according to a third embodiment. Fig. Figure 28 shows a circuit diagram of the capacitance-type liquid level detector device 800 according to a third embodiment. Implementation modes of the invention: Capacitance measuring device according to the first embodiment

[0048] As in Fig. As shown in Figure 1, a capacitance measuring device 10 in a first embodiment is a device that measures an equivalent value for a measured object capacitance “Cn”. The capacitance measuring device 10 comprises a constant voltage power source 11, a switching element SW11 for the first input, a bypass capacitor 12, a charge / discharge switching element SW10, a control or regulation element 13, and a measuring device 14.

[0049] The constant voltage power source 11 (i.e., a component of an input voltage application device) is a power source capable of applying a constant voltage input voltage "Vin". The first input switching element SW11 (i.e., another component of the input voltage application device) has one opposite end connected to one of the opposite ends of a device capacitance "Cn", and another opposite end connected switchably to a potential between the constant voltage power source 11 and ground. This means that when the first input switching element SW11 is connected to one end of the constant voltage power source 11, the input voltage "Vin" is set to a state at one of the opposite ends of the device capacitance "Cn".If, on the other hand, the first input switching element SW1 is connected to one side of the ground potential, the input voltage “Vin” is set to a state of non-applicability at one of the opposite end sides of the object capacitance “Cn”.

[0050] The bridging capacitor 12 is connected in series with the other of the opposite ends of the device capacitance "Cn" (namely, with a different or opposite end to the constant voltage power source 11) and connects the other of the opposite ends of the device capacitance "Cn" to the ground potential between the two. This means that the device capacitance "Cn" and the bridging capacitor 12 form a bridge circuit. Note that the bridging capacitor 12 has the capacitance "Cb".

[0051] The charging / discharging switching element SW10 is connected not only in series with the other of the opposite end faces of the capacitance "Cn" of the device under test, but also in parallel with the bridging capacitor 12. Additionally, the charging / discharging switching element SW10 discharges a charge at the other of the opposite end faces of the capacitance "Cn" to ground potential during the closed state.

[0052] The controller 13 alternately executes a discharge step and a charge step, which are described below. Specifically, the controller 13 sets the first input switching element SW11 to a state where it is connected to ground potential and sets the charge / discharge switching element SW11 to the closed state, thereby discharging the charge at the opposite end of the capacitance "Cn" to ground potential (i.e., the discharge step). Note that the state where the first input switching element SW11 is connected to ground potential is equivalent to the state in which the input voltage "Vin" is not applied to the capacitance "Cn". The discharge step described above adjusts the charge at the capacitance "Cn" to the ground potential, which serves as the reference state, thus enabling calibration.

[0053] Furthermore, after the previously described discharge step, the controller 13 places the first input switching element SW11 in a state of connection with one side of the constant voltage power source 11 and places the charge / discharge switching element SW10 in the open state, thereby charging the device capacitance "Cn" (i.e., charging step). Note that the state of connection of the first input switching element SW11 with the side of the constant voltage power source 11 is equivalent to the state in which the input voltage "Vin" is applied to the device capacitance "Cn".

[0054] When the controller 13 performs the charging step, the measuring device 14 determines an equivalent value for the capacitance of a measured object based on the potential “Vout” (hereinafter also referred to as “output voltage”) between the measured object capacitance “Cn” and the bypass capacitor 12. Note that the output voltage “Vout” is equivalent to a potential at the other of the opposite end faces of the measured object capacitance “Cn”.

[0055] Note that the capacitance of the object being measured, the capacitance of the bridging capacitor 12, the input voltage 'Vin' and the output voltage 'Vout' have a relationship to each other according to equation (1). Mathematical Formula 1 Cn=Cb×VoutVin−Vout

[0056] Furthermore, the capacitance “Cb” of the bridging capacitor 12 and the input voltage “Vin” are known. Therefore, the measuring device 14 can determine an equivalent value for the capacitance of the object under test “Cn” by equation (1) based on the output voltage “Vout”.

[0057] Next, we will follow based on Fig. 2. Explanation of the relationship between the opening / closing time of the charging / discharging switching element SW10, which actuates the control unit 13, the potential "Vin1" at one of the opposite ends of the capacitance "Cn", and the output voltage "Vout". Between "t1" and "t2", the charging / discharging switching element SW10 is switched to "ON" (i.e., closed). Furthermore, the first input switching element SW11 is connected to the side opposite ground potential. Therefore, the potential "Vin1" at one of the opposite ends of the capacitance "Cn" becomes ground potential.

[0058] The aforementioned operating procedures or operations discharge the charge at the measured capacitor "Cn" by means of the charge / discharge switching element SW10. As a result, the potential (or output voltage) "Vout" between the measured capacitor "Cn" and the bypass capacitor 12 becomes the ground potential, serving as the reference state. This means that, regardless of the fact that the output voltage "Vout" was undefined before the aforementioned operations, the aforementioned operations have set the output voltage "Vout" to the ground potential.

[0059] Subsequently, the charging / discharging switching element SW10 between “t2” and “t4” is set to “OFF” (i.e., to the open state), and the first input switching element SW11 is connected to the side of the constant voltage power source 11. Therefore, the potential “Vin1” at one of the opposite ends of the capacitance “Cn” is set to the input voltage “Vin”. The operations described above charge the capacitance “Cn”. After a time period required for charging has elapsed, the measuring device 14 measures the output voltage “Vout”. Fig. 2 The measuring device 14 measures the output voltage “Vout” between “t3” and “t4”.

[0060] Subsequently, between "t4" and "t5", the charging / discharging switching element SW10 is set to "ON" (i.e., closed), and the first input switching element SW11 is connected to the side opposite ground potential. These operations make the potential "Vin1" at one of the opposite ends of the capacitance "Cn" at ground potential, thereby discharging the charge at the capacitance "Cn". In particular, the previously described output voltage "Vout" is set to ground potential. Then, between "t5" and "t9", the same operations as those described between "t1" and "t5" are repeated.

[0061] As explained above, the bypass capacitor 12 is connected in series with the capacitance of the device under test “Cn”, and the measuring device (gauge) 14 determines a capacitance-equivalent value for this based on a potential at the other of the opposite ends of the capacitance of the device under test “Cn”, namely a potential between a device under test and the bypass capacitor 12 (or the output voltage “Vout”). It should be noted that, because an intermediate potential between two capacitors is indeterminate, the capacitance measured using the intermediate potential is not highly accurate.

[0062] As explained above, however, setting the charge / discharge switching element SW10 to the closed state results in the discharge of the charge at the device capacitance "Cn". In particular, the previously described output voltage (or intermediate potential) "Vout" becomes the ground potential serving as the reference state. This means that setting the charge / discharge switching element SW10 to the closed state enables calibration for the output voltage "Vout".

[0063] Furthermore, when the charging / discharging switching element SW10 is set to the open position and the input voltage "Vin" is applied to one of the opposite ends of the capacitance "Cn" after the charge has been discharged, the measuring device 14 measures a potential at the other opposite end of the capacitance "Cn". This means that the potential measured by the measuring device 14 becomes a potential that coincides with or is proportional to the capacitance "Cn". Therefore, the capacitance measuring device 10 can measure the capacitance "Cn" with a high degree of accuracy. Capacitance measuring device according to a second embodiment

[0064] As in Fig. Figure 3 shows a capacity measuring device 20 according to a second embodiment comprising a power source 11, a bridging capacitor 12, a charging / discharging switching element SW10, a control or regulation 13 and a measuring device 14.

[0065] In the capacitance measuring device 20 according to the second embodiment, a capacitance “Cy” is added to the capacitance measuring device 10 according to the first embodiment. The capacitance “Cy” is a capacitance that exists between the other of the opposite end faces of the capacitance “Cn” of the object being measured and the ground potential. For example, the capacitance “Cy” is formed between an electrode at the other of the opposite end faces of the capacitance “Cn” of the object being measured and another electrode that is located close to the first-mentioned electrode.

[0066] This means that the bypass capacitor 12 is connected in parallel with the capacitor "Cy". Note that the capacitance "Cb" of the bypass capacitor 12 is chosen to be larger than the capacitance "Cy". The capacitance "Cy" can be estimated to some extent beforehand. Therefore, the capacitance "Cb" of the bypass capacitor 12 is set accordingly. In particular, the capacitance "Cb" of the bypass capacitor 12 can be satisfactorily set to one hundred times or more the capacitance "Cy".

[0067] Note that the capacitance of the object being measured, the capacitance of the bridging capacitor 12, the input voltage, the output voltage, and the capacitance Cb have a relationship to each other according to equation (2). Mathematical Formula 2 Cn=(Cb+Cy)×VoutVin−Vout

[0068] As can be seen from equation (2), (Cb) + Cy becomes a value that approximates Cb when the capacitance Cb of the bridging capacitor 12 is entirely greater than Cy. Therefore, the capacitance Cn is derived from a relationship similar to equation (1). Thus, the degree of influence resulting from the capacitance Cy between the ground potential and the other of the opposite ends of the capacitance Cn is reliably reduced. Therefore, a highly accurate equivalent value for the capacitance Cn can be determined. Capacitance measuring device according to a third embodiment

[0069] As in Fig. Figure 4 shows a capacitance measuring device 30 corresponding to the third embodiment comprising a constant voltage power source 11, a bridging capacitor 12, a charging / discharging switching element SW10, a control or regulation 13, a measuring device 14, a first input switching element SW11, a second capacitor 31 and a second input switching element SW12.

[0070] In the capacitance measuring device 30 according to the third embodiment, the second capacitor 31 and the second input switching element SW12 are added to the capacitance measuring device 20 according to the second embodiment. The second capacitor 31 has an opposite end face to which a second constant voltage input voltage “Vin” (which is identical to the input voltage “Vin” in the present embodiment) is applied, and another opposite end face which is connected to the other of the opposite end faces of the capacitance “Cn” of the object being measured.

[0071] The second input switching element SW12 has one opposite end connected to one of the opposite ends of the second capacitor 31, and another opposite end connected switchably to one of the constant voltage power source 11 and ground potential. This means that when the second input switching element SW12 is connected to one end of the constant voltage power source 11, the second capacitor 31 is in a state where the second input voltage "Vin" is applied to one of its opposite ends. Conversely, when the second input switching element SW12 is connected to one end of ground potential, the second capacitor 31 is in a different state where the second input voltage "Vin" is not applied to either of its opposite ends.

[0072] Note that a relationship as represented in Fig. 5 is given between the switching time of the respective switching elements (SW10, SW11, SW12) that actuates the control or regulation 13, the potential “Vin1” at one of the opposite end sides of the measured object capacitance “Cn”, the potential “Vin2” at one of the opposite end sides of the second capacitance 31 and the output voltage “Vout”.

[0073] As in Fig. As shown in Figure 5, the charging / discharging switching element SW10 is set to "ON" (i.e., closed) between "t1" and "t2" and between "t5" and "t6", and to "OFF" (i.e., open) between "t2" and "t5" and between "t6" and "t9". The first input switching element SW11 is connected to ground potential between "t1" and "t3" and between "t5" and "t7", and is connected to the constant voltage power source 11 between "t3" and "t5" and between "t7" and "t9". The second input switching element SW12 is connected to ground potential between "t1" and "t2", between "t4" and "t6", and between "t8" and "t9", and is connected to the constant voltage power source 11 between "t2" and "t4" and between "t6" and "t8".

[0074] Note that a state in which the input voltage "Vin" is not applied to either opposite end faces of the capacitance "Cn" under test, and the second input voltage "Vin" is not applied to either opposite end faces of the second capacitor 31, is designated as the "first state." Another state in which the input voltage "Vin" is not applied to either opposite end faces of the capacitance "Cn," but the second input voltage "Vin" is applied to either opposite end faces of the second capacitor 31, is designated as the "second state." A further state in which the input voltage "Vin" is applied to either opposite end faces of the capacitance "Cn" under test, and the second input voltage "Vin" is applied to either opposite end faces of the second capacitor 31, is designated as the "third state."Another state, in which the input voltage “Vin” is applied to one of the opposite end sides of the object capacitance “Cn”, but the second input voltage “Vin” is not applied to one of the opposite end sides of the second capacitor 31, is referred to as the “fourth state”.

[0075] Furthermore, as in Fig. As shown in Figure 5, the states are switched in the order of the first state, the second state, the third state, and the fourth state. In this case, the output voltage "Vout" is, as shown, connected to the lowest line or conductor in the Fig. 5. Furthermore, the measuring device 14 determines an equivalent value for the measured object capacitance “Cn” based on the difference between a potential “Vo2” at the other of the opposite end faces of the measured object capacitance “Cn” in the second state from “t2” to “t3” and another potential “Vo3” at the other of the opposite end faces of the measured object capacitance “Cn” in the third state (i.e., “Vo2” - “Vo3”). Alternatively, the measuring device 14 determines an equivalent value for the measured object capacitance “Cn” based on another potential “Vo4” at the other of the opposite end faces of the measured object capacitance “Cn” in the fourth state from “t4” to “t5”.

[0076] The following are explanations of how to build an equivalent circuit in each of the states from the first state to the fourth state and the output voltage "Vout" using Fig. 6 to Fig. 9.

[0077] In the first state from "t1" to "t2" of Fig. In step 5, the charging / discharging switching element SW10 is in the closed state, and the first and second input switching elements (SW11, SW12) are connected to ground potential. Therefore, the circuit in this state is as described in Fig. 6 is shown. As in Fig. As shown in Figure 6, all capacitors (“Ca”, “Cn”, “Cy”, “Cb”) are connected to ground potential at one of their opposite ends, and these capacitors (“Ca”, “Cn”, “Cy”, “Cb”) are connected to the measuring device 14 at the other of their opposite ends. Since the charge / discharge switching element SW10 is also in the closed state, the potentials at the other of the opposite ends of the capacitors (“Ca”, “Cn”, “Cy”, “Cb”) become ground potential (which in this case is zero). Equation (3) below describes the potential “Vo1” (or an output voltage “Vout”) that the measuring device 14 measures under these conditions. This means that the potential “Vo1” becomes zero and serves as the reference state potential. Mathematical Formula 3 Vo1=0Ca+Cn+(Cy+Cb)×Vin

[0078] In the second state from "t2" to "t3" of Fig. 5. The charging / discharging switching element SW10 is in the open position, the first input switching element SW11 is connected to ground potential, and the second input switching element SW12 is connected to the constant voltage power source 11. Under these conditions, as described in Fig. As shown in Figure 7, the capacitor “Ca” is connected to the constant voltage power source 11 at one of its opposite ends, while the other capacitors (“Cn”, “Cy”, “Cb”) are connected to ground potential at one of their opposite ends. This means that the potential “Vo2” measured by the measuring device 14 becomes an intermediate potential between the capacitor “Ca” and the sum of the capacitances (“Cn”, “Cy”, “Cb”). Equation (4) below describes the potential “Vo2” measured by the measuring device 14 under these conditions. This means that the potential “Vo2” becomes a potential equivalent to the capacitor “Ca” of the second capacitor 31. Mathematical Formula 4 Vo2=CaCa+Cn+(Cy+Cb)×Vin

[0079] In the third state from "t3" to "t4" of Fig. 5. The charging / discharging switching element SW10 is set to the open state, and the first and second input switching elements (SW11, SW12) are connected to the constant voltage power source 11. Under these conditions, as described in Fig. As shown in Figure 8, the capacitors (“Ca”, “Cn”) are connected to the constant voltage power source 11 at one of the opposite ends, while the other capacitors (“Cy”, “Cb”) are connected to ground potential at one of the opposite ends, and these capacitors (“Ca”, “Cn”, “Cy”, “Cb”) are connected to the measuring device 14 at the other of the opposite ends. This means that the potential “Vo3” measured by the measuring device 14 becomes an intermediate potential between a summed value of the capacitors (“Ca”, “Cn”) and another summed value of the capacitors (“Cy”, “Cb”). Equation (5) below describes the potential “Vo3” measured by the measuring device 14 under these conditions. This means that the potential “Vo3” becomes a potential equivalent to the summed value of the capacitors (“Ca”, “Cn”). Mathematical Formula 5 Vo3=Ca+CnCa+Cn+(Cy+Cb)×Vin

[0080] In the fourth state from "t4" to "t5" of Fig. 5. The charging / discharging switching element SW10 is in the open position, the first input switching element SW11 is connected to the constant voltage power source 11, and the second input switching element SW12 is connected to ground potential. Under these conditions, as described in Fig. As shown in Figure 9, the capacitor “Cn” is connected to the constant voltage power source 11 at one of the opposite ends, while the other capacitors (“Ca”, “Cy”, “Cb”) are connected to ground potential at one of the opposite ends, and these capacitors (“Ca”, “Cn”, “Cy”, “Cb”) are connected to the measuring device 14 at the other of the opposite ends. This means that the potential “Vo4” measured by the measuring device 14 results in an intermediate potential between the capacitor “Cn” and a sum of the capacitor values ​​(“Ca”, “Cy”, “Cb”). Equation (6) below describes the potential “Vo4” measured by the measuring device 14 under these conditions. This means that the potential “Vo4” becomes a potential equivalent to the capacitance “Cn”. Mathematical Formula 6 Vo4=CnCa+Cn+(Cy+Cb)×Vin

[0081] Note that the measuring device 14 can determine an equivalent value for the device capacitance "Cn" based on the potential "Vo4" at the other of the opposite end faces of the device capacitance "Cn" in the fourth state from "t4" to "t5", as described above. For a measurement using the potential "Vo4", switching back and forth between the first and fourth states is sufficient. However, since the potential "Vo4" is a value close to ground potential, it may be affected by noise.

[0082] This allows the measuring device 14 to determine a better, highly accurate capacitance-equivalent value by calculating an equivalent value for the capacitance "Cn" based on the difference between the potential "Vo2" at the opposite end of the capacitance "Cn" in the second state from "t2" to "t3" and the potential "Vo3" at the opposite end of the capacitance "Cn" in the third state (i.e., "Vo2" - "Vo3"). This means that the difference between the output voltage "Vo2" associated with the second state and the output voltage "Vo3" associated with the third state can be used by switching the activation time of the first input switching element SW11 and the second input switching element SW12 in the following sequence: first state, second state, third state, fourth state (see diagram). Fig. 5. Capacitance measuring device according to a fourth embodiment

[0083] A capacity measuring device according to a fourth embodiment differs from the capacity measuring device 30 according to the third embodiment only with regard to the switching operations or actions for the charging / discharging switching element SW10. As in Fig. As shown in Figure 10, the charging / discharging switching element SW10 is set to "OFF" (i.e., to the open state) between "t1" and "t2", between "t3" and "t6", and between "t7" and "t9", and to "ON" (i.e., to the closed state) between "t2" and "t3" and between "t6" and "t7". Note that the following description is the same as for the third embodiment, namely the first input and second input switching elements (SW11, SW12), the potential "Vin1" at one of the opposite end faces of the measured object capacitance "Cn", and the potential "Vin2" at one of the opposite end faces of the second capacitor 31.

[0084] While the conditions of the second state, in which the charging / discharging switching element SW10 is in the closed position, are selected as the reference state, a calibration is performed. This means that the output voltage "Vout" has a value resulting from the output voltage "Vo2" being set to 0 under the conditions of the second state between "t2" and "t3" or between "t6" and "t7". Therefore, the measuring device 14 can determine an equivalent value for the measured object capacitance "Cn" simply by measuring the output voltage "Vo3" characteristic of the third state. Capacitance-type flat sensor device according to a first embodiment

[0085] Next, explanations will follow regarding a capacitance-type flat sensor device in which one of the previously described capacitance measuring devices is used. Overall structure of the capacity-type sensor device

[0086] As in Fig. 11 and in Fig. As shown in Figure 12, a capacitance-type flat sensor device 100 comprises a sensor body 110 which is designed in the form of a layer (or in a flat form), whereby a capacitance (that is, a measured object capacitance) between electrodes in the sensor body 110 is measured.

[0087] It should be noted that the sensor body 110 can be implemented as a pressure-sensitive sensor that detects the position and magnitude of given external forces, but also as a touch-sensitive field that detects positions with which a conductor, such as a person's finger, comes into contact or to which it approaches. Furthermore, as described in Fig. 11 and in Fig. Figure 12 shows the capacitance-type flat sensor device 100, the sensor body 110, and a capacitance measuring device 160. Detailed structure of the sensor body 110

[0088] In the present embodiment, the sensor body 110 is formed in the form of a layer, exhibits flexibility, and possesses extensibility properties. The sensor body 110 can be configured not only as a flat shape but also as a shape with a curved surface. However, the sensor 110 with a flat shape is described below as an example. Fig. 11 and Fig. 12 described. Note that if the sensor body 110 is implemented as a touch-sensitive field, as described above, flexibility and stretchability are not necessarily required.

[0089] The sensor body 110 includes first electrodes 120 (for example, 121 to 128) arranged in several rows, second electrodes 130 (for example, 131 to 138) arranged in several columns, a dielectric layer 141, and insulating layers (142, 143). Fig. 12 shown)). The respective first electrode components (121 to 128) in the first electrodes 120 arranged in several rows are formed in the form of a strip and are positioned such that they run in an upward / downward direction in Fig. 11 are elongated and parallel to each other.

[0090] The respective second electrode components (131 to 138) in the second electrodes 130 arranged in several columns are arranged in the form of a strip and positioned such that they run in a right / left direction in Fig. 11 are elongated and parallel to each other. Note that, notwithstanding the fact that the first electrodes 120 are arranged in several rows and the second electrodes 130 are arranged in several columns, Fig. 11 are represented in a sentence of eight rows and eight columns, but this is in no way limited to that.

[0091] The first electrodes 120, arranged in several rows, and the second electrodes 130, arranged in several columns, are arranged such that they are separated from each other by a distance in the surface normal line direction (i.e., in the leaf or layer surface front / back direction). Fig. 11 and in the upward / downward direction in Fig. 12) are separated and are arranged with an orientation relative to each other. Both are positioned such that the orientation positions between the first electrodes 120, arranged in multiple rows, and the second electrodes 130, arranged in multiple columns, form a matrix. This means that each of the first electrode components (121 to 128) is oriented towards each of the second electrode components (131 to 138), so that the orientation positions between them form a matrix with eight rows and eight columns. Each of the positions arranged in the form of an eight-row, eight-column matrix can be a measurement position for a capacitance.

[0092] Furthermore, the respective first electrode components (121 to 128) and the respective second electrode components (131 to 138) are formed by incorporating a conductive filler into an elastomer or resin. Therefore, the first and second electrodes (120, 130) exhibit flexibility and also possess extensibility properties.

[0093] For the elastomer forming the first and second electrodes (120, 130), the following, for example, can be used: silicone rubber, ethylene-propylene copolymerized rubber, natural rubber, styrene-butadiene copolymerized rubber, acrylonitrile-butadiene copolymerized rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, and the like. Furthermore, the conductive filler incorporated into the first and second electrodes (120, 130) can be selected with satisfactory results in the form of conductive particles, and fine particles, such as carbon materials and metals, can be used for this purpose.Furthermore, the following, for example, can be used for the resin that forms the first and second electrodes (120, 130): polyester resin, modified polyester resin, polyether urethane resin, polycarbonate urethane resin, vinyl chloride vinyl acetate copolymer, phenolic resin, acrylic resin, polyamide imide resin, polyamide resin, nitrocellulose, modified nitrocelluloses and the like.

[0094] The dielectric layer 141 is arranged between each of the first electrodes (121 to 128) and each of the second electrodes (131 to 138). If the sensor body 110 is implemented as a pressure-sensitive sensor, the dielectric layer 141 is designed to be compressionally deformable so that its thickness can be varied as a result of external forces.

[0095] The dielectric layer 141 is formed from an elastomer or resin, exhibits flexibility, and possesses extensibility properties in the same way as the first and second electrodes (120, 130). Examples of suitable elastomers for the dielectric layer 141 include silicone rubber, acrylonitrile-butadiene copolymerized rubber, acrylic rubber, epichlorolhydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, and the like. Furthermore, examples of suitable resins for the dielectric layer 141 include polyethylene resin, polypropylene resin, polyurethane resin, polystyrene resin (including cross-linked foamed polystyrene resin), polyvinyl chloride-polyvinylidene chloride copolymer, ethylene acetic acid copolymer, and the like.

[0096] The insulating layers (142, 143) are arranged such that they cover a front surface on one side of the first electrodes 120 and a rear surface on one side of the second electrodes 130, respectively. The insulating layers (142, 143) exhibit flexibility and extensibility properties in the same way as the first and second electrodes (120, 130). The materials described above for the elastomer or resin forming the dielectric layer 141 are suitable for the elastomer or resin forming the insulating layers (142, 143).

[0097] As in Fig. As shown in 12, when an external compression force “F” is applied to the sensor body 110 with the above-described structure in the surface normal line direction of the sensor body 110 (i.e. in the upward / downward direction in Fig. 12) is applied, deforming the dielectric layer 141 in the surface normal direction. As a result, the separation distance between the first electrodes 120 and the second electrodes 130, located on parts subjected to the external force "F", decreases. Under these conditions, the capacitance between the first electrodes 120 and the second electrodes 130 on the parts increases. This makes it possible to measure the positions subjected to the external force "F" by measuring the change in capacitance with respect to each of the matrix-arranged positions where each of the first electrodes (121 to 128) is opposite each of the second electrodes (131 to 138). Additionally, it is possible to measure the magnitude of the external force "F" by measuring each of the absolute values ​​of the capacitances at the matrix-arranged positions. Sensor body circuitry

[0098] Note that the sensor body 110 consists of first electrodes 120 arranged in eight rows and second electrodes 130 arranged in eight columns, as for example in Fig. The structure is shown in Figure 11. However, to simplify the explanations of the capacitance measuring devices presented here, explanations of the first electrodes 120 (for example, 121 to 123) arranged in three rows and the second electrodes 130 (for example, 131 to 133) arranged in three columns follow.

[0099] In this case, a circuit diagram of the sensor body 110 is as shown in Fig. Figure 13 shows that capacitances ("C1" to "C9") exist between the respective first electrodes (121 to 123) and the respective second electrodes (131 to 133). For example, a capacitance between the first electrode 121 and the second electrode 131 is designated "C1", while another capacitance between the first electrode 122 and the second electrode 132 is designated "C2". Note that the terminals of the respective first electrodes 121 to 123 are labeled Pi1 to Pi3, while the terminals of the respective second electrodes 131 to 133 are labeled Po1 to Po3. Construction of the capacitance measuring device

[0100] Next, explanations will follow regarding the construction of a capacity measuring device 160 based on Fig. 14 and Fig. 15. It should be noted that the capacitance measuring device 160, according to the present embodiment, has the same circuit design as the capacitance measuring device 30 according to the third embodiment, which is based on Fig. As explained in section 4, it is used.

[0101] In Fig. Connections to the terminals (Pi1 to Pi3) of the respective first electrodes (121 to 123) are sequentially connected in the sensor body 110. Additionally, connections to the terminals (Po1 to Po3) of the respective second electrodes (131 to 133) are sequentially connected in the sensor body 110. To simplify the explanations, the following are explanations for the case in which the measurement object position is opposite or opposite to that of the first electrode component 121 and the second electrode component 131 for measuring the capacitance "C1". Fig. 14 is designated.

[0102] As in Fig. As shown in Figure 14, the capacitance measuring device 160 comprises a constant voltage power source 11, a bridging capacitor 12, a charging / discharging switching element SW10, and a control or regulation unit (not explicitly shown in Figure 14). Fig. Figure 14 shows a measuring device 14, a first input switching element SW11, a second capacitor 31, a second input switching element SW12, and switches (SW121 to SW123, SW131 to SW132) for changing the object being measured. The same reference numerals or symbols used in the third embodiment are used below for the constituent elements of the capacitance measuring device 160 according to the present embodiment, insofar as they are identical to those of the capacitance measuring device 30 according to the third embodiment.

[0103] The device-of-measurement change switches (SW121 to SW123) connect one of the terminals (Pi1 to Pi3) of the first electrodes (121 to 123) to the constant voltage power source 11 and connect the other two to ground potential. This allows the device-of-measurement change switches (SW121 to SW123) to connect the terminals to the constant voltage power source 11. The device-of-measurement change switches (SW131 to SW133) connect one of the terminals (Po1 to Po3) of the second electrodes (131 to 133) to the measuring device 14 and connect the other two to ground potential. This allows the device-of-measurement change switches (SW131 to SW133) to connect the terminals to the measuring device 14.Note that the object change switch SW121 is connected to the constant voltage power source 11, the switch SW131 is connected to the measuring device 14, and the other switches (SW122, SW123, SW132, SW133) are connected to the ground potential.

[0104] The bypass capacitor 12 has a capacitance "Cb" that is set to a constant value. The bypass capacitor 12 is connected to the respective second electrodes (131 to 133) on opposite sides by means of the respective device-of-measurement change switches (SW121 to SW123). The bypass capacitor 12 is connected to ground potential on the other opposite side. The capacitance "Cb" of the bypass capacitor 12 is set to a constant value that is larger than the capacitances at other positions among the matrix-arranged positions located between ground potential and the second electrode 131 at the device-of-measurement position. The capacitance "Cb" of the bypass capacitor 12 is set to a constant value that is one hundred times or more greater than the capacitances at the aforementioned other device-of-measurement positions.If the capacitance at the measurement position is equal to "C1", then the capacitances at the other positions under the matrix-arranged positions become the sum of "C2" and "C3". This means that the capacitance "Cb" of the bridging capacitor 12 is set such that it is one hundred times or more the sum of "C2" and "C3".

[0105] Note that when measuring the capacitance "C1", the capacitances ("C4", "C7") between the first electrode component 121 and the ground potential have virtually no effect on the potential "Vout" measured by the measuring device 14. Furthermore, the capacitances ("C5", "C6", "C8", "C9") between the other first electrode components (122, 123) connected to the ground potential and the other second electrode components (132, 133) also connected to the ground potential have virtually no effect on the potential "Vout". Therefore, the electrical circuit of the sensor body 110 can be... Fig. 14 by an equivalent circuit diagram, as it appears in Fig. Figure 15 shows how to represent this. For the sake of generalization, the capacitance "C1" is chosen to be equal to "Cn", which describes a measured object capacitance, and the sum of the capacitances "C2" and "C3" is used, as shown in Figure 15. Fig. Figure 15 is labelled “Cy”. The respective symbols are the same as the symbols in the aforementioned capacitance measuring device 30 according to the third embodiment.

[0106] The in Fig. The circuit shown in 15 corresponds to the one in Fig. The circuit shown in section 4 is equivalent. Consequently, actuating or activating the respective switching elements (“SW10”, “SW11”, “SW12”) enables the measuring device 14 to determine the capacitance “C1” at the measuring object position with high accuracy. Capacitance-type flat sensor device according to a second embodiment

[0107] The following are explanations of a capacitance-type flat sensor device 200 according to a second embodiment based on Fig. 16 and Fig. 17. As in Fig. Figure 16 shows a sensor body 210 of the capacitance-type flat sensor device 200, further comprising a third electrode 220, which is connected to the sensor body 110, as shown in Fig. As shown in Figure 12, the third electrode 220 is added. It is positioned such that it faces the second electrodes 130 on the opposite side from the first electrodes 120 and is connected to ground potential. This means that the third electrode 220 is located on a rear surface of the second electrodes 130 (i.e., in Fig. 16 on a lower side) is arranged through the insulating layer 230. The third electrode 220 has a size that is essentially comparable to that of the insulating layer 143. In addition, the third electrode 220 is covered by the insulating layer 143 on its rear surface.

[0108] Fig. Figure 17 shows a circuit diagram for this case. A capacitor formed by the second electrodes 130 and the third electrode 200 acts as a bridging capacitor 12, as shown in Fig. Figure 15 shows that a capacitance between the second electrodes 130 and the third electrodes 220 becomes "Cb". Since the bridge capacitor 12 is formed using the third electrode 220, it is not necessary to provide a dedicated capacitor. Therefore, the resulting setup is simplified. Furthermore, since the electrode elements are designed to integrally represent the capacitances ("Cn", "Cb"), the two capacitances accurately reflect temperature changes. Therefore, even after temperature changes, it is possible to measure the capacitance "Cn" of the object under test with high accuracy. Capacitance-type flat sensor device according to a third embodiment

[0109] The following are based on Fig. 18 Explanations of a capacitance-type flat sensor device 300 according to a third embodiment. As in Fig. Figure 18 shows a sensor body of the capacitance-type flat sensor device 300 in the same way as the sensor body 210 according to the illustration in Fig. 16. However, the third electrode 220 is not connected to the ground potential, but to the second input switching element SW12.

[0110] This means that a capacitor formed by the second electrodes 130 and the third electrode 220 represents the second capacitor 31, as shown in Fig. As shown in Figure 18, this means that the capacitance between the second electrode 130 and the third electrode 220 becomes "Ca". Accordingly, a separate capacitor is unnecessary. Furthermore, since the electrode elements are designed to integrally represent the capacitances ("Cn", "Ca"), the two capacitances accurately reflect temperature changes. Consequently, even after temperature changes, it is possible to measure the capacitance "Cn" of the object under test with high accuracy. Capacitance-type flat sensor device according to a fourth embodiment

[0111] The following are based on Fig. 19 and Fig. 20. Explanations of a capacitance-type flat sensor device according to a fourth embodiment. In the embodiments described above, the measuring device 14 is selected such that it determines an equivalent value for the capacitance "Cn" based on the difference between the potential "Vo2" at the other of the opposite end faces of the capacitance "Cn" in the second state from "t2" to "t3" and the potential "Vo3" at the other of the opposite end faces of the capacitance "Cn" in the third state (that is, ("Vo2" - "Vo3")). Alternatively, the measuring device 14 is set such that it determines an equivalent value for the capacitance "Cn" based on the potential "Vo4" at the other of the opposite end faces of the capacitance "Cn" in the fourth state from "t4" to "t5".

[0112] In contrast to the previously described calculation methods, the measuring device 14 determines the measured object capacitance “Cn” by solving simultaneous equations in the present embodiment. Equation (7) below describes simultaneous equations, where the capacitances (“Cn1”, “Cn2”, “Cn3”) are chosen as unknown quantities. This means that the simultaneous equations according to equation (7) are expressed by the input voltage “Vin”, the respective voltages (“Vout1”, “Vout2”, “Vout3”) at the selected second electrode 131, and the unknown capacitances (“Cn1”, “Cn2”, “Cn3”) at the multiple positions where the second selected electrode 131 intersects each of the first electrodes (121, 122, 123) arranged in multiple rows in three dimensions. Mathematical Formula 7 {(Vin−Vout1)⋅Cn1−Vout1⋅Cn2−Vout1⋅Cn3=Vout1⋅Cb−Vout2⋅Cn1+(Vin−Vout2) ⋅Cn2−Vout2⋅Cn3=Vout2⋅Cb−Vout3⋅Cn1−Vout3⋅Cn2+(Vin−Vout3)⋅Cn3=Vout3⋅Cb

[0113] The capacities (“Cn1”, “Cn2”, “Cn3”) can be determined by solving the simultaneous equations according to equation (7). The other capacities (“Cn4” to “Cn9”) can be determined in the same way by solving the other simultaneous equations.

[0114] Here, the technique for solving simultaneous equations according to the present embodiment is compared with the technique according to the previously described embodiments when the capacitances ("C1 to "C9") are selected from 1 pF to 9 pF. The results are presented in Fig. 20 shown. In Fig. 20 The white circles denote the selected capacities, while the white squares describe the consequences that result from solving the simultaneous equations according to the present embodiment, and the black circles describe the consequences that result from the technique of non-simultaneous equations according to the predetermined embodiments.

[0115] As in Fig. As shown in Figure 20, the technique of solving simultaneous equations yields a highly accurate capacitance compared to the technique using non-simultaneous equations. Note that when measuring a potential at the opposite end of one of the measured object's capacitances, the non-simultaneous equation technique assumes that the potential will be affected by the other capacitances. Since the technique of solving simultaneous equations is a calculation that takes these other capacitances into account, it becomes possible to determine the capacitance with a high degree of accuracy. Alternative to the capacitance-type flat sensor device

[0116] In the sensor devices described above, according to the second and third embodiments, the electrode elements are designed such that they integrally exhibit the capacitances (“Cn”, “Cb”) or (“Cn”, “Ca”). Beyond these configurations, the electrode elements can also be designed with satisfactory results to integrally exhibit the capacitances (“Cn”, “Ca”, “Cb”). This makes it possible to measure the object capacitance (“Cn”) with even greater accuracy, even when temperatures have changed. Note that it is not necessary to overlap all electrodes sequentially. The electrodes provide the aforementioned advantages even when each electrode is formed on an identical substrate. Capacitance-type liquid level detector device according to a first embodiment

[0117] Next, explanations will follow regarding the construction of a capacitance-type liquid level detector device using one of the previously described capacitance measuring devices. Overall structure of the capacity-type liquid level detector device

[0118] Based on Fig. 21. Explanations of the construction of the capacity-type liquid level detector device (hereinafter referred to as the "liquid level detector device") follow. The liquid level detector device detects a liquid level and a liquid property within a fuel tank 610 of a vehicle. As in Fig. As shown in Figure 21, the fuel tank 610 is mounted on a vehicle and stores or holds gasoline that serves as fuel.

[0119] Note that a situation arises in which water or methanol is mixed with the liquid being supplied, in addition to the gasoline. The liquid level detector determines whether the liquid in question is gasoline, water, methanol, or something similar. Furthermore, the liquid level detector assesses the liquid level of the liquid itself, that is, the liquid level of the gasoline, the liquid level of the water, and the liquid level of the methanol. It should be noted that if another liquid is present, or even if, for example, a floating liquid is present, the liquid level detector can also be used to assess this.

[0120] The fuel tank 610 has a depression 611 in the bottom center, aligned with the vehicle's left / right orientation, and a corresponding surface depression 612 on the upper surface. This means that the depression 611 and the surface depression 612 are oriented opposite each other in the upward / downward direction. Furthermore, a hole 613 is formed in a portion of the upper surface of the fuel tank 610. A detachable connector is coupled to the hole 613.

[0121] An electrode unit 620 is arranged inside the fuel tank 610, forming a capacitive liquid level detector device 600. The electrode unit 620 is positioned centrally in the vehicle's right / left direction and is fixed between the lower bottom recess 611 and the upper surface recess 612 in the fuel tank 610.

[0122] The electrode unit 620 comprises a sensor body 621, which is in the form of a rod, and a pressure element 622, which is arranged at an upper end of the sensor body 621 and is designed to extend from an upper end surface of the sensor body 621. The sensor body 621 has a lower end that is positioned in the bottom recess 611 in the base of the fuel tank 610. The pressure element 622 is pressed against the recess 612 in the upper surface of the fuel tank 610 (i.e., against the direction of extension). The electrode unit 620, thus constructed, is fixed between the bottom recess 611 and the surface recess 612 in the fuel tank 610.

[0123] In addition, the sensor body 621 further includes a plurality of electrode pairs (626a to 626i) which are arranged in an offset or staggered manner in the upward / downward direction (i.e., in the vertical direction) within the fuel tank 610. The capacitances between the respective electrode pairs in the multiple electrode pairs (626a to 626i) differ depending on the type of fluid present.

[0124] The liquid level detector device 600 further comprises a capacitance measuring device 630, which is electrically connected to the multiple electrode pairs (626a to 626i) of the electrode unit 620, and an evaluation unit 640.

[0125] The capacity measuring device 630 is located outside the fuel tank 610 and is practically exposed to the influence of one of the previously described capacity measuring devices. The evaluation unit 640 evaluates the liquid level and the liquid properties within the fuel tank 610 based on capacities (“C1” to “C9”) determined by the capacity measuring device 630. Sensor body of the electrode unit

[0126] Next, we will follow based on Fig. 22. Detailed explanations of the sensor body 621 of the electrode unit 620. The several electrode pairs (626a to 626i) are placed in the sensor body 621 in an offset or staggered manner in the vertical direction of a substrate surface. The capacitances of the respective electrode pairs (626a to 626i) are designated as “C1” to “C9” in this order from the bottom up.

[0127] Wiring leads (hereinafter referred to as "application-side wiring leads") (627a to 627c) are provided, which are electrically connected to one of the electrodes of the respective electrode pairs in the multiple electrode pairs (626a to 626i). Furthermore, wiring leads (hereinafter referred to as "output-side wiring leads") (628a to 628c) are provided, which are electrically connected to another of the electrodes of the respective electrode pairs therein.

[0128] The first application-side wiring lead 627a is connected to the electrode pairs (626a, 626d, 626g), the second application-side wiring lead 627b is connected to the electrode pairs (626b, 626e, 626h), and the third application-side wiring lead 627c is connected to the electrode pairs (626c, 626f, 626i). The first output-side wiring lead 628a is connected to the electrode pairs (626a, 626b, 626c), the second output-side wiring lead 628b is connected to the electrode pairs (626d, 626e, 626f), and the third output-side wiring lead 628c is connected to the electrode pairs (626g, 626h, 626i).

[0129] Note that terminals connecting to the application-side wiring lines (627a, 627b, 627c) are designated Pi1, Pi2, and Pi3, respectively. The other terminals connecting to the output-side wiring lines (628a, 628b, 628c) are designated Po1, Po2, and Po3, respectively.

[0130] An equivalent circuit of the sensor body 621 described above is as shown in Fig. Figure 23 shows the circuit of the liquid level detector device 600. Therefore, the circuit is as shown in Figure 600. Fig. Figure 24 illustrates this. This means that the liquid level detector device 600 is equivalent to a matrix-arranged circuit in the same way as the capacitance-type flat sensor device 100. If this is the case with respect to the liquid level detector device 600, then it becomes possible to use the previously described capacitance-type flat sensor device 100 in the same way.

[0131] Furthermore, the assessment unit 640 evaluates the liquid levels at the respective altitudes based on the capacities ("C1" to "C9") determined by the measuring device 14 at those altitudes. Simultaneously, the assessment unit 640 can evaluate the liquid properties at the respective altitudes based on the capacities ("C1" to "C9") at those altitudes. Capacitance-type liquid level detector device according to a second embodiment

[0132] In the liquid level detector device 600 according to the first embodiment, the electrodes forming the respective electrode pairs are selected such that they are each located at the same height. In the liquid level detector device 700 according to the present embodiment, however, the respective electrodes (726a to 726t) are positioned such that they are offset or stacked in the vertical direction, as shown in Fig. Figure 25 shows that the electrodes connected to the application-side wiring lines (727a to 727c) and the electrodes connected to the output-side wiring lines (728a to 728c) are arranged alternately in the vertical direction.

[0133] An equivalent circuit in this case is as shown in Fig. 26 is shown. Fig. 26 is the capacitance of the object being measured, designated “Cn1”, and the capacitance of the second capacitor 31 (equivalent to the reference sign “31” of Fig. 24) is labelled “Ca1”. This means that the previously described second capacitor 31 is formed by a capacitor consisting of electrode 726b (that is, one of the electrodes of the two measuring object electrodes (726b, 726c) arranged on a lower side) and electrode 726a (which is arranged on a further lower side).

[0134] An evaluation unit 740 evaluates boundaries between different types of liquids based on equivalent values ​​for the measured object capacitances (“Cn1” to “Cn8”). For example, if a liquid of the same type is present at one position between electrodes 726b and 726c, which are adjacent vertically, and at another position between electrodes 726a and 726b, which are adjacent vertically, then “Cn1” becomes identical to “Ca1”. In this case, the difference between a potential equivalent to “n1” and another potential equivalent to “Ca1” becomes 0.

[0135] In contrast, liquids of different types are present at one position between electrodes 726b and 726c, which are adjacent in the vertical direction, and at another position between electrodes 726a and 726b, which are adjacent in the vertical direction, where “Cn1” and “Ca1” have different values. In this case, the difference between a potential equivalent to “Cn1” and another potential equivalent to “Ca1” is not zero. The evaluation unit 740 assesses the boundary between the liquids based on this difference. Capacitance-type liquid level detector device according to a third embodiment

[0136] Next, we will follow based on Fig. 27 and Fig. 28 Explanations of a liquid level detector device 800 according to a third embodiment. The liquid level detector device 800 according to the present embodiment differs from the liquid level detector device 700 according to the second embodiment in that output-side wiring lines (828a to 828c) are used as a bridging capacitor 12.

[0137] This means that the output-side wiring lines (828a, 828b, 828c) are sufficiently formed in the vertical direction of the electrode assembly 620. This procedure leads to the construction of the electrodes of the bridging capacitor 12 of the output-side wiring lines (828a, 828b, 828c), as shown in Fig.28 is shown. It is therefore not necessary for the liquid level detector device 800 to be provided with a bypass capacitor 12 that serves only one purpose or is specifically provided or dedicated, according to the present embodiment. Explanation of reference symbols (10, 20, 30, 160, 630) Capacity measuring devices 11 Constant voltage power source 12 Bridging capacitor 13 Control or regulation 14 Measuring device 31 second capacitor (100, 200, 300) capacity-type flat sensor devices (110, 210) Sensor body 120 first electrodes 130 second electrodes 141 dielectric layer (142, 143, 230) insulating layers 220 third electrode (600, 700, 800) capacity-type liquid level detector devices 610 Fuel tank 611 Soil depression 612 Surface depression 613 Hole opening 620 electrode unit (621, 721) Sensor body 622 Pressure element (626a to 626i, 726a to 726t) Electrodes (640, 740) Assessment units SW10 Charging / Discharging Switching Element SW11 first input switch element SW12 second input switch (“Cn”, “Cn1”) Measurement device capacities “Cb” Capacitance of the bridging capacitor 12 ("Ca", "Ca1") Capacitances of the second capacitor

Claims

[1] Capacity measuring device (160, 630), comprising: Input voltage application device for applying a constant voltage input voltage to one of the opposite end sides of a capacitance (Cn) of a device under test; a bridging capacitor (12) which is connected in series with another of the opposite end faces of the device capacitance (Cn) and connects the other of the opposite end faces of the device capacitance (Cn) to a ground potential between the two; a charging / discharging switching element (SW10) which is connected in series with the other of the opposite end sides of the device capacitance (Cn) and is connected in parallel with the bridging capacitor (12), whereby a charge at the other of the opposite end sides of the device capacitance (Cn) is discharged to the ground potential during a closed state of this; a control or regulation (13) that performs the following steps: a step of setting the input voltage application device to a state in which the input voltage is not applied, and setting the charge / discharge switching element (SW10) to the closed state thereof, thereby discharging the charge at the device capacitance (Cn) to the ground potential; and a step of setting the charging / discharging switching element (SW10) to an open state and setting the input voltage application device to a state in which the input voltage is applied, after the discharge step, thereby charging the measured object capacitance (Cn); and a measuring device (14) for determining an equivalent value for the capacitance of the object being measured (Cn) based on a potential between the capacitance of the object being measured (Cn) and the bridging capacitor (12) in the charging step carried out by the control or regulation (13). [2] Capacitance measuring device (160, 630) according to claim 1, wherein the input voltage application means includes: a constant voltage power source (11) with the capability of applying the input voltage; and a first input switching element (SW11) which is connected at one of the opposite end sides of this to one of the opposite end sides of the device capacitance (Cn), and at the other of the opposite end sides of this to one of the constant voltage power source (11) and the ground potential, and switches back and forth between a state in which the constant voltage power source (11) applies the input voltage to the device capacitance (Cn) and another state in which the constant voltage power source (11) does not apply the input voltage to the device capacitance (Cn). [3] Capacitance measuring device (160, 630) according to claim 1 or 2, wherein the capacitance measuring device (160, 630) further comprises: a second capacitor (31) having an opposite end side to which a second constant voltage input voltage is applied, and another opposite end side which is connected to the other of the opposite end sides of the capacitance (Cn) of the object being measured. [4] Capacitance measuring device (160, 630) according to claim 3, wherein states thereof are switched in the following sequence: a first state in which neither the input voltage nor the second input voltage is applied; a second state in which one input voltage and the second input voltage are applied, but the other is not applied; a third state in which both are supplied by the first input voltage and the second input voltage; and a fourth state in which one of the input voltages and the second input voltage is not applied, but the other of these is applied; wherein the measuring device (14) determines an equivalent value for the device capacitance (Cn) based on a potential at the other of the opposite end faces of the device capacitance (Cn) in the second state, the third state or the fourth state. [5] Capacitance measuring device (160, 630) according to one of claims 1 to 4, wherein a capacitance of the bridging capacitor (12) is selected as a larger capacitance compared to a capacitance between the ground potential and the other of the opposite end sides of the object capacitance (Cn). [6] Capacitance measuring device (160, 630) according to any one of claims 1 to 5, wherein the capacitance measuring device (160, 630) determines each of the equivalent values ​​for several object capacitances in a sensor body (110) thereof; and An equivalent circuit of the sensor body (110) includes: several rows of first electrodes (120), several columns of second electrodes (130) for placement such that these form a matrix shape with the first electrodes (120) arranged in several rows, and several dielectric layers (141) arranged at several positions where the first electrodes (120) arranged in several rows and the second electrodes (130) arranged in several columns intersect each other three-dimensionally; wherein the equivalent values ​​for the multiple object capacitances in the sensor body (110) are equivalent values ​​for capacitances between the first electrodes (120) and the second electrodes (130) corresponding to the respective positions in the multiple dielectric layers (141). [7] Capacity measuring device (160, 630) according to claim 6, wherein the measuring device (14) solves simultaneous equations which are expressed by the following: respective voltages (Vout1, Vout2, Vout3) at the second electrodes (130) that are selected when the input voltage is applied to one of the first electrodes (120) of the first electrodes (120) arranged in multiple rows and the other remaining first electrodes (120) are connected to ground potential; and Capacitances (Cn1, Cn2, Cn3) that serve as unknown quantities and occur at several positions where the selected second electrodes (130) intersect each of the first electrodes (120) arranged in multiple rows in three dimensions; whereby the measuring device (14) determines equivalent values ​​for the respective capacities (Cn1, Cn2, Cn3) which serve as unknown quantities in the simultaneous equations. [8] Capacitance-type flat sensor device (100, 200), comprising: First electrodes (120) arranged in several rows, which are formed in strip form and are placed alternately parallel to each other; Second electrodes (130) arranged in several columns, which are formed in strip form and are placed alternately parallel to each other, wherein the second electrodes (130) arranged in several columns are arranged in opposite positions to the first electrodes (120) arranged in several rows such that they are opposite to the first electrodes (120) in order to form a matrix shape; a dielectric layer (141) arranged between each of the first electrodes (120) in the first electrodes (120) arranged in multiple rows and each of the second electrodes (130) in the second electrodes (130) arranged in multiple columns; and the capacitance measuring device (160, 630) according to claim 1 for determining an equivalent value for a capacitance at each of the matrix-shaped positions corresponding to a position opposite to each of the first electrodes (120) to each of the second electrodes (130); wherein the first electrodes (120) form one of the opposite end faces of the device capacitance (Cn); and the second electrodes (130) form the other of the opposite end faces of the object capacitance (Cn). [9] Capacitance-type flat sensor device (100, 200) according to claim 8, wherein the capacitance-type flat sensor device (100, 200) further comprises a third electrode (220) arranged such that it is opposite to the second electrodes (130) on a side with respect to the first electrodes (120) and is connected to ground potential; and a capacitor formed by the second electrodes (130) and the third electrode (220) forms the bridging capacitor (12). [10] Capacitance-type flat sensor device (100, 200) according to claim 8, wherein the capacitance-type flat sensor device (100, 200) further comprises a third electrode (220) which is arranged such that it is opposite to the second electrodes (130) on a side with respect to the first electrodes (120); wherein the capacitance measuring device (160, 630) further comprises a second capacitor (31) having an opposite end face to which a second constant voltage input voltage is applied, and another opposite end face which is connected to the other of the opposite end faces of the capacitance of the object being measured (Cn); and wherein a capacitor formed by the second electrodes (130) and the third electrode (220) forms the second capacitor (31). [11] Capacitance-type liquid level detector device (600, 700, 800), comprising: several electrodes, which are placed in a staggered manner in the vertical direction of this within a liquid-storing tank; the capacitance measuring device (160, 630) according to claim 1 for determining an equivalent value for a capacitance between two electrodes selected from among the several electrodes as an equivalent value for the capacitance of the object being measured (Cn); and an assessment unit (640) for assessing a liquid level inside the tank based on the equivalent value for the measuring object capacity (Cn). [12] Capacitance-type liquid level detector device (600, 700, 800) according to claim 11, wherein the evaluation unit (640) evaluates a liquid quality based on the equivalent value for the measured object capacity (Cn). [13] Capacitance-type liquid level detector device (600, 700, 800) according to claim 11, wherein the capacitance measuring device (160, 630) further comprises a second capacitor (31) having an opposite end side to which a second constant voltage input voltage is applied, and another opposite end side which is connected to the other of the opposite end sides of the object capacitance (Cn); wherein a capacitor formed by the two electrodes of the object (726b, 726c), one of which is located on a lower side and the other on a further lower side, forms the second capacitor (31); and The assessment unit (640) assesses a boundary between different types of liquids based on the equivalent value for the measuring object capacity (Cn).

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