JP5642438B2 - Capacitance measuring apparatus and capacitance measuring method - Google Patents

Description

  The present invention relates to a capacitance measuring device and a capacitance measuring method configured to be able to measure a capacitance between a pair of measurement points of a measurement object.

  As this type of capacitance measuring apparatus, the applicant discloses an LCR tester in Japanese Utility Model Laid-Open No. 6-30779. In this LCR tester disclosed by the applicant, an alternating current flowing through this sample is supplied while supplying an AC voltage for measurement of frequency f introduced from a voltage controlled oscillator (external signal source) outside the apparatus between both ends of the sample to be measured. A configuration is employed in which the current value of the current and the voltage value of the voltage between both ends of the sample are measured, and the capacitance between both ends of the sample is calculated by an arithmetic process using each measured value.

Japanese Utility Model Publication No. 6-30779 (pages 15-19, FIG. 1-5)

  However, the LCR tester disclosed by the applicant has the following problems to be improved. In other words, the LCR tester disclosed by the applicant employs a configuration in which the capacitance of the sample is calculated based on each measurement value measured while supplying a measurement AC voltage across the sample to be measured. . In this case, among the capacitors that are one of the measurement objects of this type of measuring device, capacitors (such as multilayer ceramic capacitors) in which a ferroelectric material is used are stopped when voltage supply is stopped (the electric field is applied). It is known that when the applied electric field is removed later, a so-called polarization history phenomenon occurs in which the charge bias remains.

  Therefore, in this type of measuring apparatus, for example, after measuring the capacitance of the multilayer ceramic capacitor (that is, after supplying the AC voltage for measurement), the capacitance of the measurement object is re-measured. When this is done, a value different from the capacitance value measured during the first measurement process is measured. For this reason, in this type of measuring device, when a capacitor in which a ferroelectric material is used is used as a measuring object, the reproducibility of the measured value is deteriorated. Therefore, it is preferable to improve this point.

  The present invention has been made in view of such a problem to be improved. In a measurement process for a capacitor in which a ferroelectric material is used, a static electricity capable of accurately measuring the capacitance of the measurement object. The main object is to provide a capacitance measuring device and a capacitance measuring method.

In order to achieve the above object, the capacitance measuring apparatus according to claim 1, wherein an AC signal generating unit that generates an AC signal supplied between a pair of measurement points of a measurement object, and the AC signal between the two measurement points. A measurement unit that performs a measurement process for measuring the current of the AC signal flowing between the two measurement points and the voltage between the two measurement points in a state where the current is supplied, the measured current, the voltage, and the A calculation unit that calculates a capacitance between the two measurement points based on a phase difference between a current and the voltage, and a control unit that controls the AC signal generation unit, the measurement unit, and the calculation unit, AC signal generating unit is configured to change the amplitude of the AC signal in accordance with control of the control unit, prior to the start of the measurement process, by controlling the AC signal generating unit, the measurement process Sometimes both measuring points The said while gradually reducing the amplitude from a first larger second amplitude than the amplitude of the AC signal to supply the AC signal between the two measurement points, thereby supplied between the two measurement points supplied to When the amplitude of the AC signal becomes the first amplitude, the measurement unit is controlled to start the measurement process .

Further, in the capacitance measuring method according to claim 2, the current of the AC signal flowing between the two measurement points in a state where the AC signal is supplied between the pair of measurement points of the measurement object, and between the measurement points. A capacitance measurement method that executes a measurement process for measuring a voltage and calculates a capacitance between the two measurement points based on the measured current, the voltage, and the phase difference between the current and the voltage. Prior to the start of the measurement process, the amplitude is gradually decreased from the second amplitude larger than the first amplitude of the AC signal supplied between the measurement points during the measurement process. the AC signal is supplied to, the measurement process starts when the amplitude of the AC signal that is supplied between the two measurement points becomes the first amplitude.

According to the capacitance measuring apparatus according to claim 1 and the capacitance measuring method according to claim 2 , the AC signal supplied between the pair of measurement points of the measurement object at the time of the measurement process prior to the start of the measurement process. Even when the capacitance is measured using a capacitor having a polarization history characteristic as a measurement object by supplying an AC signal between both measurement points while gradually decreasing the amplitude from the first amplitude. The capacitance can be measured in a state where the amount of polarization remaining in the measurement object is sufficiently reduced (or in a state where the polarization history of the measurement object is substantially removed). Therefore, according to the capacitance measuring apparatus and the capacitance measuring method, in the measurement process using a capacitor or the like using a ferroelectric as a measurement object, the capacitance of the measurement object is accurately measured. As a result, the reproducibility of the capacitance measurement can be improved.

Also, by gradually decreasing the amplitude of the measurement process the AC signal supplied between both measuring points prior to the start of the second amplitude, the amplitude of the AC signal supplied across the measured object 1 Capacitance can be measured in a state in which the amount of polarization remaining in the measurement object is further reduced (or in a state in which the polarization history is substantially removed) as compared with a configuration in which the polarization is reduced only once. Therefore, the capacitance of the measurement object can be measured more accurately, and as a result, the reproducibility of the capacitance measurement can be further improved.

Furthermore, the amplitude of the measurement process the AC signal supplied between both measuring points prior to the start of gradually decreasing from the second amplitude, the amplitude of the AC signal being supplied between the two measurement points first By starting the measurement process when the amplitude becomes, the process of supplying an AC signal between the two ends of the measurement object is completed in order to reduce the remaining amount of polarization (or remove the polarization history). Since the measurement process is immediately started at the time point, the time required to measure the capacitance of the measurement object can be shortened accordingly.

1 is a configuration diagram showing a configuration of a capacitance measuring device 1. FIG. 4 is an explanatory diagram for explaining an AC signal Sac supplied to both ends of a measurement object 10. FIG. It is explanatory drawing for demonstrating the relationship between amplitude A1-A7 of alternating current signal Sac, and polarization amount Bx-B7. FIG. 6 is an explanatory diagram for explaining another AC signal Sac supplied to both ends of the measurement object 10.

  Hereinafter, embodiments of a capacitance measuring device will be described with reference to the accompanying drawings.

  A capacitance measuring device 1 shown in FIG. 1 is an example of a measuring device configured to be able to measure a capacitance between a pair of measurement points of a measurement object 10, and includes an AC signal generation unit 2 and a measurement unit 3. , A calculation unit 4 and a control unit 5 are provided. The AC signal generation unit 2 generates an AC signal Sac in accordance with the control signal S1 from the control unit 5 and supplies the AC signal Sac to both ends of the measurement object 10 (an example of “a pair of measurement points of the measurement object”). . In this case, the AC signal generation unit 2 is configured to be able to change the amplitude of the AC signal Sac according to the control of the control unit 5. Specifically, for example, the AC signal generation unit 2 is configured to be able to arbitrarily change the amplitude of the AC signal Sac to be output in multiple stages according to the control signal S1 from the control unit 5.

  The measurement unit 3 follows the control signal S2 from the control unit 5 and the current I flowing between both ends of the measurement object 10 in a state where the AC signal Sac is supplied between both ends of the measurement object 10 by the AC signal generation unit 2. Current value (AC signal current) and the voltage value V of the voltage V generated between both ends (voltage between both measurement points) are measured to generate measurement value data D1, and the generated measurement value data D1 is used as the calculation unit 4 The measurement process to be output to is executed. The calculation unit 4 is based on the measurement value data D1 output from the measurement unit 3 according to the control signal S3 from the control unit 5, specifically, the current value and voltage of the current I specified by the measurement value data D1. Based on the voltage value of V and the phase difference between the current I and the voltage V, the capacitance between both ends of the measurement object 10 is calculated to generate calculation result data D2, and the generated calculation result data D2 is controlled. Output to unit 5.

The control unit 5 comprehensively controls the capacitance measuring device 1. Specifically, the control unit 5 outputs the control signal S <b> 1 to the AC signal generation unit 2 to generate the AC signal Sac and supply the AC signal Sac between both ends of the measurement object 10. In this case, in the capacitance measuring apparatus 1, as shown in FIG. 2, the amplitude A0 (“first amplitude”) of the AC signal Sac supplied between both ends of the measuring object 10 during the measurement process by the measuring unit 3 is performed. The measurement object of the AC signal Sac having an amplitude A1 (an example of “second amplitude”) larger than the AC signal Sac and the AC signal Sac having an amplitude A2 smaller than the amplitude A1 prior to the start of the measurement process. 10 are continuously supplied in this order between both ends.

  More specifically, in this capacitance measuring apparatus 1, the control unit 5 controls the AC signal generation unit 2 to set the amplitude of the AC signal Sac supplied between both ends prior to the start of the measurement process. When the amplitude of the AC signal Sac is gradually decreased from the amplitude A1 and the amplitude of the AC signal Sac is decreased to the amplitude A0 (when the AC signal Sac having the amplitude A0 is supplied between both ends: when the time point t1 arrives), the measuring unit 3 is Control to start the measurement process. In addition, said amplitude A0 shall be about +/- 6V as an example, and said amplitude A1 shall be the largest voltage value in the rated voltage range of the measuring object 10. FIG. As a result, the polarization history of the amount of polarization that may remain in the measurement object 10 by supplying (applying) a voltage within the rated voltage range to the measurement object 10 is sufficient as described later. The amount of polarization can be made small (or the polarization history can be removed).

  In addition, the control unit 5 outputs the control signal S2 to the measurement unit 3 to execute the measurement process of the current value and the voltage value, and outputs the control signal S3 to the calculation unit 4 so that the measurement unit 3 The calculation processing of the capacitance of the measurement object 10 based on the measured value data D1 is executed. Furthermore, the control unit 5 displays a calculation result based on the calculation result data D2 from the calculation unit 4 on a display unit (not shown). In this case, in this capacitance measuring device 1, the first measurement processing mode executed when there is no possibility that the measurement object 10 has the polarization history, and the measurement object 10 has the polarization history. The second measurement processing mode to be executed when there is a possibility of being selected can be selected and executed. Therefore, the control unit 5 controls the AC signal generation unit 2, the measurement unit 3, the calculation unit 4, and the like according to the mode selection by the user using an operation unit (not shown).

  When measuring the capacitance by the capacitance measuring device 1, first, as shown in FIG. 1, the capacitance measuring device 1 is connected to the measurement object 10. Next, an operation unit (not shown) is operated to instruct the start of the measurement process. At this time, polypropylene capacitors, polystyrene capacitors, mica capacitors, etc. (an example of “capacitors having no substantial polarization history characteristics”), unused multilayer ceramic capacitors, etc. (“with polarization history characteristics”) When the measurement object 10 is an example of a “capacitor with no polarization history remaining,” the first measurement mode is selected.

  When this measurement mode is selected, the control unit 5 outputs the control signal S1 to the AC signal generation unit 2, thereby generating the AC signal Sac having the amplitude A0 and supplying the AC signal Sac between both ends of the measurement object 10. Next, the control unit 5 outputs a control signal S2 to the measurement unit 3 to start measurement processing. At this time, the measuring unit 3 determines the current value of the current I (see FIG. 1) flowing between both ends in a state where the AC signal generating unit 2 supplies the AC signal Sac having the amplitude A0 between both ends of the measurement object 10. , And the voltage value of the voltage V between both ends (see FIG. 1), respectively, and the measurement value data D1 is generated based on the measured current value and voltage value, and is output to the calculation unit 4.

  Subsequently, the control unit 5 outputs the control signal S <b> 3 to the calculation unit 4 to calculate the capacitance between both ends of the measurement object 10. At this time, the calculation unit 4 is based on the measurement value data D1 output from the measurement unit 3, the current value of the current I flowing between both ends of the measurement object 10, the voltage value of the voltage V between both ends, and the current I And the phase difference between the voltages V are specified, and the capacitance between both ends of the measurement object 10 is calculated using the specified value. The calculation unit 4 generates calculation result data D2 based on the calculation result and outputs the calculation result data D2 to the control unit 5. The measurement process by the measurement unit 3 and the calculation process by the calculation unit 4 are the same as the known measurement process and calculation process, and thus detailed description thereof is omitted. Thereafter, the control unit 5 specifies the capacitance of the measurement object 10 based on the calculation result data D2 output from the calculation unit 4, and displays the specified result on a display unit (not shown). Thus, the measurement process in the first measurement mode for the measurement object 10 is completed.

  On the other hand, when the object to be measured 10 is a multilayer ceramic capacitor having a voltage supply history (application history) or the like (an example of a “capacitor with polarization history remaining”), the second measurement mode is selected. To do. When this measurement mode is selected, the control unit 5 first executes a process of reducing the polarization amount of the polarization history remaining in the measurement object 10 (or a process of removing the polarization history), and subsequently Then, a measurement process similar to the series of measurement processes executed in the first measurement process mode is executed. Specifically, the control unit 5 first outputs the control signal S1 to the AC signal generation unit 2 to generate the AC signal Sac. At this time, as shown in FIG. 2, the AC signal generation unit 2 receives the AC signal Sac having an amplitude A1 larger than the amplitude A0 of the AC signal Sac supplied between both ends of the measurement object 10 during the measurement process by the measurement unit 3. Is supplied between both ends of the measurement object 10, and the amplitude thereof is gradually reduced in multiple steps to the amplitude A0.

Contact name in the figure, in order to facilitate the understanding of the operating principle of the capacitance measuring device 1, only one cycle of the AC signal Sac of one amplitude are illustrated, in practice, the same amplitude Example of a state in which an AC signal Sac having an amplitude smaller than the AC signal Sac is output for a plurality of cycles after the AC signal Sac is output for a plurality of cycles (“amplitude is gradually reduced in multiple stages”). ).

  In this case, as shown in FIG. 3, when the polarization history of the polarization amount Bx remains in the measurement object 10, the amplitude of the AC signal Sac supplied between both ends gradually decreases from the amplitude A1 to the amplitude A5. As a result, the amount of polarization remaining in the measurement object 10 is decreased stepwise from the polarization amount Bx to the polarization amount B5. Specifically, when the AC signal Sac having the amplitude A2 is supplied after the AC signal Sac having the amplitude A1 is supplied, the polarization amount of the polarization history remaining in the measurement object 10 remains the polarization amount Bx. After that, when the AC signal Sac having the amplitude A3 is supplied after the AC signal Sac having the amplitude A2 is supplied, the polarization amount of the measurement object 10 decreases from the polarization amount Bx to the polarization amount B3.

  When the AC signal Sac having the amplitude A4 is supplied after the AC signal Sac having the amplitude A3 is supplied, the polarization amount of the measurement object 10 decreases from the polarization amount B3 to the polarization amount B4, and the AC signal Sac having the amplitude A4. When the AC signal Sac having the amplitude A5 is supplied after is supplied, the polarization amount of the measuring object 10 decreases from the polarization amount B4 to the polarization amount B5. Furthermore, when the AC signal Sac having the amplitude A0 is supplied after the AC signal Sac having the amplitude A5 is supplied, the polarization amount of the measurement object 10 is further reduced than the polarization amount B5. Therefore, by gradually reducing the amplitude of the AC signal Sac supplied between both ends, the amount of polarization remaining in the measurement object 10 can be sufficiently reduced.

  Next, when the amplitude of the AC signal Sac supplied between both ends of the measurement object 10 reaches the amplitude A0 (when the time point t1 in FIG. 2 arrives), the control unit 5 sends a control signal to the measurement unit 3. S2 is output to start the measurement process. At this time, since the amount of polarization of the measurement object 10 is sufficiently reduced, the current value of the current flowing between both ends of the measurement object 10 and the voltage value of the voltage generated between both ends are accurately measured. The In addition, the control unit 5 outputs the control signal S3 to the calculation unit 4 to calculate the capacitance between both ends of the measurement object 10. At this time, since the capacitance is calculated based on the accurate measurement value, the reproducibility of the capacitance measurement is good. Thereafter, the control unit 5 specifies the capacitance of the measurement object 10 based on the calculation result data D2 output from the calculation unit 4, and displays the specified result on a display unit (not shown). Thus, the measurement process in the second measurement mode for the measurement object 10 is completed.

As described above, according to the capacitance measuring device 1 and the capacitance measuring method by the capacitance measuring device 1, the control unit 5 controls the AC signal generating unit 2 before starting the measurement process. The amplitude is gradually decreased from a second amplitude (amplitude A1 as an example) larger than the first amplitude (in this example, amplitude A0) of the AC signal Sac supplied between the pair of measurement points of the measurement object 10. By supplying the AC signal Sac between the two measurement points while the capacitance is measured using the capacitor having the polarization history characteristic as the measurement object 10, it remains in the measurement object 10. The capacitance can be measured in a state where the amount of polarization is sufficiently reduced (or in a state in which the polarization history of the measuring object 10 is substantially removed). Therefore, according to the capacitance measuring device 1 and the capacitance measuring method using the capacitance measuring device 1, the measurement is performed in the measurement process using the capacitor or the like using the ferroelectric as the measuring object 10. As a result of accurately measuring the capacitance of the target object 10, the reproducibility of the capacitance measurement can be improved.

  In addition, according to the capacitance measuring device 1 and the capacitance measuring method using the capacitance measuring device 1, the control unit 5 controls the AC signal generating unit 2 to perform both before the start of the measurement process. Compared with a configuration in which the amplitude of the AC signal Sac supplied between the measurement object 10 is reduced only once by gradually decreasing the amplitude of the AC signal Sac supplied between the measurement points from the second amplitude. Since the capacitance can be measured in a state where the amount of polarization remaining in the measurement object 10 is further reduced (or in a state where the polarization history is substantially removed), the measurement object As a result of measuring the capacitance of 10 more accurately, the reproducibility of the capacitance measurement can be further improved.

Further, according by the capacitance measuring device 1 and the capacitance measuring device 1, the capacitance measuring method, the control unit 5, and controls the AC signal generating unit 2, prior to the start of the measurement process both The amplitude of the AC signal Sac supplied between the measurement points is gradually decreased from the second amplitude, and the amplitude of the AC signal Sac supplied between the two measurement points is the first amplitude (in this example, the amplitude A0). In this case, the measurement unit 3 is controlled to start the measurement process so that the remaining polarization amount is reduced (or the polarization history is removed). Since the measurement process is started immediately when the process of supplying Sac is completed, the time required to measure the capacitance of the measurement object 10 can be shortened accordingly.

Na us, fed across an AC signal Sac amplitude A0 large amplitude A1 than the AC signal Sac for supplying across the measured object 10 at the time of measurement processing by the measurement tough 3, gradually reducing its amplitude In the above description, the configuration in which the measurement process by the measurement unit 3 is started when the amplitude of the supplied AC signal Sac becomes the amplitude A0 (time point t1 in FIG. 2) is described as an example. After gradually reducing the amplitude of the AC signal Sac to be supplied from A1 to A0, the supply of the AC signal Sac to both ends is stopped at time t1 shown in FIG. In other words, after the supply of the AC signal Sac is stopped for the time T between the time point t1 and the time point t2, the supply of the AC signal Sac having the amplitude A0 is started again at the time point t2, and the measurement by the measuring unit 3 is performed. Configuration and method for starting the process may be employed. Even when such a configuration and method are employed, the same effects as those of the capacitance measuring device 1 and the capacitance measuring method can be obtained.

  Further, with respect to the AC signal Sac supplied between both ends of the measurement object 10 before the measurement process by the measurement unit 3, as shown in FIG. 4, the amplitude A1 larger than the amplitude A0 of the AC signal Sac supplied during the measurement process. May be gradually reduced to an amplitude A7 smaller than the amplitude A0. When such an AC signal Sac is supplied between both ends of the measuring object 10, when the amplitude of the measuring object 10 is reduced as the amplitudes A2, A3, A4,. The amount of polarization is reduced to the amount of polarization Bx, B3, B4,. Therefore, as shown in FIG. 2, the measurement object is more than when the AC signal Sac whose amplitude decreases within the range of the amplitudes A1 to A5 (the amplitude larger than the amplitude A0 of the AC signal Sac supplied during the measurement process) is supplied. The amount of polarization remaining at 10 can be further reduced. As a result, when this configuration and method are adopted, the capacitance of the measuring object 10 can be measured more accurately, and as a result, the reproducibility of the capacitance measurement can be further improved. In this configuration and method as well, after the supply of the AC signal Sac is stopped for the time T between the time point t1 and the time point t2, the supply of the AC signal Sac having the amplitude A0 is started again at the time point t2, and the measurement by the measuring unit 3 is performed. A configuration for starting the processing can also be adopted.

  Furthermore, although the capacitance measuring device 1 having the AC signal generation unit 2 configured to gradually change the amplitude A of the AC signal Sac in multiple steps has been described as an example, the amplitude A of the AC signal Sac is steplessly determined. That is, even in a capacitance measuring device (not shown) having an AC signal generation unit configured to gradually change linearly, the AC signal Sac is performed according to the same procedure as the series of processes by the capacitance measuring device 1 described above. The same effect can be obtained by reducing the amplitude of.

DESCRIPTION OF SYMBOLS 1 Capacitance measuring apparatus 2 AC signal generation part 3 Measurement part 4 Calculation part 5 Control part 10 Measuring object A0-A7 Amplitude B3-B7, Bx Polarization amount D1 Measurement value data D2 Calculation result data I Current V Voltage S1-S3 Control signal Sac AC signal T Time t1, t2

Claims (2)

An AC signal generator that generates an AC signal supplied between a pair of measurement points of the measurement object, and the AC signal that flows between the measurement points in a state where the AC signal is supplied between the measurement points. A measurement unit that executes a measurement process for measuring the current and the voltage between the two measurement points; and the static between the two measurement points based on the measured current, the voltage, and the phase difference between the current and the voltage. A calculation unit that calculates a capacitance; and a control unit that controls the AC signal generation unit, the measurement unit, and the calculation unit,
The AC signal generation unit is configured to change the amplitude of the AC signal according to the control of the control unit,
Wherein, prior to the start of the measurement process, by controlling the AC signal generating unit, the first large second amplitude than the amplitude of the AC signal to be supplied to between both the measuring points during the measurement process The AC signal is supplied between the two measurement points while gradually reducing the amplitude from the measurement point, and the measurement unit receives the amplitude of the AC signal supplied between the two measurement points to the first amplitude. A capacitance measuring device that starts the measurement process by controlling the . In the state in which an AC signal is supplied between a pair of measurement points of the measurement object, a measurement process is performed to measure the current of the AC signal flowing between the measurement points and the voltage between the measurement points, and the measured current A capacitance measuring method for calculating a capacitance between the two measurement points based on the voltage, and the phase difference between the current and the voltage,
Wherein prior to the start of the measurement process, the between the measurement process the first of the two measuring points while gradually reducing the amplitude from a large second amplitude than the amplitude of the AC signal to be supplied to between both the measuring points at A capacitance measuring method for supplying an AC signal and starting the measurement process when the amplitude of the AC signal supplied between the two measurement points becomes the first amplitude .

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