KR20030032874A - Method for determining pass or failure of capacitor - Google Patents

Abstract

PURPOSE: To shorten an examination time for reducing a manufacturing time and a manufacturing cost. CONSTITUTION: An electric current iall generated in a capacitor during charging is divided into a plurality of electric current components icap, iline, and ileak mutually different in an electric current change, and an approximation formula showing their current changes with the lapse of time is formed. The determination reference electric current component ileak serving as a reference of good/ defect determination of the capacitor is extracted from a plurality of the electric current components icap, iline, and ileak, and a good/defect determination condition is set on the basis of the approximation formula. When the determination reference electric current component ileak obtained by measurement and included in electric current during charging the capacitor to be determined is compared with the good/defect determination condition, it is determined the capacitor to be determined is good or defect.

Description

Method for determining pass or failure of capacitor

The present invention relates to a method of determining whether or not a capacitor, particularly a large-capacity ceramic capacitor using a high dielectric constant magnet, can be most suitably carried out.

In a capacitor, while charging is in progress by application of a DC voltage, a large current flows during charging. In an ideal capacitor, no current flows at all when charging is complete. However, in real capacitors, current continues to flow even when charging is completed. This is a phenomenon that occurs because the insulation resistance of the actual capacitor is a finite value. Such a phenomenon is not preferable because of the fact that heat is generated by current flowing through the insulation resistance, which leads to wasteful consumption of electric power, and in the case of a capacitor having a low insulation resistance, a short circuit is expected in the future. There is even a risk associated with the continuous use, such as failure of the back and the like.

As a method of determining the quality of a ceramic capacitor based on the above viewpoint, there exists an insulation resistance test. This test is carried out as follows.

The manufactured capacitor is charged by applying a DC voltage between predetermined chargers. After charging is completed, the leakage current component of the capacitor is also measured while maintaining voltage application. Then, the insulation resistance R (Ω) = E / I is obtained from the applied voltage E (V) and the leakage current component I (A).

Then, the calculated insulation resistance R (Ω) is compared with a predetermined threshold, and when the insulation resistance is higher, the capacitor is judged as good quality, and when it is low, it is judged as defective product. The threshold is defined in advance by the JIS standard or the like for each type of capacitor.

With the recent increase in the capacity of multilayer capacitors, the charging time of the capacitors is prolonged. Therefore, a long time is required from applying a DC voltage to the capacitor until the insulation resistance can be measured. As a result, the number of capacitors that can be inspected per unit time is small.

On the other hand, in the JIS standard etc., the following processes are recognized in order to suppress the decrease of the number of inspections per unit time. The JIS standard and the like permit the measurement of the charging current at the time when 60 seconds have elapsed after the application of the charging DC voltage and the prediction of the above-described insulation resistance R (Ω) based on the measured current value.

However, even if such a process is performed, it requires a long time on the production line of 60 seconds for the inspection time of one capacitor, which shortens the manufacturing time of the capacitor and reduces the manufacturing cost. I was having a hard time doing it.

Accordingly, a main object of the present invention is to provide a method for determining whether the capacitor is capable of shortening the manufacturing time and reducing the manufacturing cost by reducing the inspection time.

BRIEF DESCRIPTION OF THE DRAWINGS It is a graph which shows the time change of the charging characteristic of the capacitor in Embodiment 1 of this invention.

2 is a graph showing an example of the relationship between the applied voltage V and the current rising rate RI.

3 is a simulation result of the charging characteristic in a state in which a rated voltage V _std is applied to a virtual threshold capacitor, and a simulation result of the charging characteristic in a state in which an applied voltage V _a is applied to _a virtual threshold capacitor. A graph representing.

4 is a graph showing an example of charging characteristics of the virtual good capacitors and the virtual threshold capacitors according to the second embodiment.

It is a figure which shows the structure of the quality determination apparatus which implemented the quality determination method of this invention.

<Brief description of the main parts of the drawing>

i _all : Current i _cap : Current component

i _line : current component i _leak : leakage current component

t _cap : first time domain t _line : second time domain

t _leak : 3rd time zone V: applied voltage

RI: Current Rising Rate V _std : Rated Voltage

V _max : Actual maximum applicable voltage

A _std , A _a : second to third time domain transform points

S: threshold

In order to achieve the above object, the method of determining whether the capacitor of the present invention has the following configuration.

According to the present invention, after separating the electrical characteristics generated in the capacitor during charging into a plurality of characteristic components having different characteristic changes over time, an approximate expression representing the time variation of each characteristic component is prepared. An approximate expression creating step; A determination and determination condition setting step of extracting a determination reference characteristic component which is a criterion for the determination of the acceptance of the capacitor from the plurality of characteristic components and setting the acceptance determination condition of the determination reference characteristic component based on the approximation equation; And a judging step of judging the quality of the judgment target capacitor by combining the judgment reference characteristic component included in the electrical characteristics during charging of the judgment subject capacitor obtained by the measurement with the above judgment conditions.

By having such a structure, it has the following effects. That is, the time change of the electrical characteristics used for the acceptance determination can be predicted with high accuracy in advance, whereby the optimum and the fastest conditions can be obtained in the acceptance determination of the capacitor.

In addition, as in the present invention, it is preferable to use a current as the electrical characteristics.

In addition, as in the present invention, the pass / fail condition setting step is a step of setting a decision threshold value of the judging reference characteristic component as the pass / fail decision condition, wherein the judging step is determined by the measurement of the judgment target capacitor. It is preferable that it is a step of determining the quality of a judgment target capacitor based on the comparison of the determination reference characteristic component extracted from the said electrical characteristic obtained and the said determination threshold value.

In addition, as in the present invention, the above approximation formulating step includes a plurality of currents in which charging current generated in the capacitor during charging is different from each other in current change over time, and also including leakage current components of the capacitor as one of them. After separating into components, an approximation equation indicating a time change of each current component is created, and the acceptance judgment condition setting step is performed after extracting the leakage current component as the determination reference characteristic component, and then determining the leakage current component. A threshold value is set based on the above approximation equation, and the determination step is based on a comparison of the leakage current component included in the current during charging of the capacitor to be determined obtained by the measurement with the judgment threshold value. It is preferable that it is a step of determining pass or fail. This is because the leakage current component is suitable as a criterion for determining whether the capacitor is good or bad.

In addition, as in the present invention, the above approximation formulating step includes a plurality of currents in which charging current generated in the capacitor during charging is different from each other in current change over time, and also including leakage current components of the capacitor as one of them. After separating into components, an approximation equation indicating a time change of each current component is generated, and the acceptance determination condition setting step is the determination reference characteristic component, which is a component of the leakage current component generated due to the product quality of the capacitor. After estimating the charging current whose value changes under the influence of the variation, the step of setting the determination threshold of the estimated value of the charging current based on the approximation equation, wherein the determination step is a determination target capacitor obtained by measurement Is a step of determining whether or not the determination target capacitor is based on a comparison of the charging current of It is preferred. By doing so, the time required for the determination can be made shorter than the time required for the determination based on the leakage current time.

In addition, as in the present invention, the approximation formula creation step is a step of preparing the approximation expression in a condition that can shorten the acceptance determination time as much as possible, and the acceptance determination condition setting step is as short as possible. The step of setting the acceptance judgment conditions of the determination reference characteristic component under the conditions that can be performed, and the determination step is a step of measuring the electrical characteristics of the capacitor to be measured under conditions that can shorten the acceptance determination time as much as possible. It is preferable. By doing so, the time required for determination can be further shortened.

In addition, as in the present invention, the approximation equation creating step is a step of preparing the approximation equation in a state in which a substantial maximum voltage that can be applied to the measurement target capacitor is applied. A step of setting the condition for determining the quality of the determination reference characteristic component in a state where a substantial maximum voltage is applied, wherein the determination step is a step of measuring the electrical characteristic in a state where the substantial maximum voltage is applied to a capacitor to be measured. It is preferable. By doing so, the following effects can be obtained. In other words, in the state where the substantial maximum voltage is applied, the time required for charging becomes substantially shortest. In the present invention, the time required for the acceptance determination can be shortened by setting the acceptance determination conditions of the determination reference characteristic component in the state.

Embodiment of the Invention

(Embodiment 1)

First, the charging characteristic of the capacitor focused on this embodiment is demonstrated. The charging characteristic indicates a time change in the amount of current flowing through the capacitor by applying a voltage. Hereinafter, the measurement of this time change is referred to as measurement of the charging characteristic.

Based on the detailed examination of the charging process of the capacitor, the inventors of the present invention show that the current flowing when charging the capacitor (hereinafter referred to as current at charging) (i _all ) is the current component (i _cap ), current component (i _line ), and leakage. At the same time, it was found that the current component i _leak was constituted by a combination of a plurality of current components, i _leak , and at the time of charging, the current i _all was found by the following equation (1).

i _all = i _cap + i _line + i _leak ... (One)

In addition, the current component i _cap is a current component flowing in the capacitor based on the true capacitance component, and the current component i _line is a current component flowing when charged with respect to the dielectric constituting the capacitor, and a leakage current. The component (i _leak ) is a leakage current component generated due to a structural problem of the capacitor.

In addition, it has also been found that the current components i _cap , i _line and i _leak are obtained by an approximation equation shown in the following equations (2) to (4).

i _cap = ae ^-bt . (2)

i _line = ct- ^f . (3)

i _leak = g. (4)

t: elapsed time after the start of current application

e: base of natural logarithm (≒ 2.71828)

a, b, c, f, g: integers determined by the characteristics of each capacitor

The constants a, b, c, f and g can be calculated by measuring the charging characteristics of a large number of samples (capacitors) at short time intervals of 10 ms or less, and then calculating the data repeatedly by computer using an optimization method or the like. Can be.

In the present embodiment, first, an approximation equation of each current component (i _cap , i _line , i _leak ) constituting the charging characteristic is created for the charging characteristic of the capacitor to be measured.

FIG. 1 shows a graph in which the time change of the current i _all during charging, which _prepares an approximation formula for each current component i _cap , i _line , and i _leak , is plotted. FIG. 1 shows the charging characteristics (time change of the current i _all at the time of charging) of a capacitor to which a constant voltage (for example, 16 V) is applied in a constant temperature environment (for example, room temperature). The horizontal axis represents time (log value) t, and the vertical axis represents current (log value).

As shown in FIG. 1, in the charging characteristic of the capacitor, the first time region t _cap , the second time region t _ilne , and the third time region t _leak exist. In these time domains, the first time domain t _cap is the fastest in time, followed by a second time domain t _line , and finally a third time domain t _leak . have.

The first time region t _cap is a time region in which the current component i _cap appears most frequently in comparison with other current components, and the current i _all during charging in this time region t _cap (log) Decreases substantially in a line with the quantitative change of the current component (i _cap ) over time (logarithm) (see equation (2) above).

The second time domain (t _line ) is a time domain in which the current component (i _cap ) is constrained to zero as much as possible, and instead, the current component (i _line ) appears most frequently in comparison with other current components. The current i _all (log) during charging in the time domain t _line is substantially changed according to the quantitative change of the current component (i _line ) with the passage of time (log) (see equation (3) above). Decreases linearly.

The third time region (t _leak ) is a time region in which the current component (i _line ) is constrained to zero as much as possible, and instead, the leakage current component (i _leak ) appears most frequently in comparison with other current components. The current i _all at the time of charging (t _leak ) (log) is the current value because the leakage current component (i _leak ) peculiar to the capacitor flows regardless of the passage of time (see (4) above). Is always substantially constant.

Here, the leak current component (i _leak ) is, as described above, the third time region (i.e., the time domain after the current component (i _cap ) or the current component (i _line ) generated during charging is preferably constrained to zero. t _leak ) to form the main component of the current. Therefore, in the conventional pass / fail determination method, the leakage current component (i _leak ) is measured by waiting for the third time area (t _leak ) to be measured and, therefore, the leakage current component (which is a determination reference characteristic component) i _leak ) measurement (calculation of insulation resistance) required a relatively long time.

In the capacitor having such a charging characteristic, the inventor of the present invention examined the formulas (1) to (4) described above in detail, and found that the first and second characteristics described below exist in the charging characteristic of the capacitor. .

First, the first feature will be described. In the case where the charging characteristics of the virtual good capacitor and the virtual defective capacitor are simulated based on the equations (1) to (4) under the condition that the applied voltage (V) is the same, between the charging properties of both (good / bad) The difference occurs in the value of the leakage current component (i _leak ), but does not occur in the value of the current component (i _cap ) or the current component (i _line ).

Looking at the charging characteristics of the capacitor based on the first feature, it can be seen that: When the value of the leakage current component (i _leak ) serving as the threshold for the acceptance judgment is determined, the capacitor serving as the threshold for the acceptance determination when an arbitrary applied voltage V is applied (hereinafter, referred to as a virtual threshold capacitor) ) Can be simulated based on the formulas (1) to (4) above.

Next, the second feature will be described. The inventor of the present invention approximates the relationship between each current component (i _cap , i _line , i _leak ) and the applied voltage (V) by a method such as least square method. It was found that when V) is increased, the current during charging increases, and at this time, the current rising rate (RI) of each current component (i _cap , i _line , i _leak ) with respect to the voltage is significantly different from each other.

That is, when comparing current component (i _line) current increase rate (RI [i _line]) and the current increase rate (RI [i _leak]) of the leakage current component (i _leak) of, RI [i _line] than RI [i _leak ] is significantly larger (RI [i _line ] <RI [i _leak ]).

In addition, the approximation can be calculated using the exponent (Aexp [BV]), the power (AV ^B ), or the polynomial (A + BV ² + CV ³ +…), but other equations may be used. The calculation of the coefficient may be calculated by a dedicated computer program, or may be calculated using an approximation derivation function such as table calculation software.

This second feature will be described in more detail. The graph of FIG. 2 shows an example of the relationship between the applied voltage V and the current rising rate RI. Fig. 2 shows various applied voltages (16V, 32V, 48V, 64V, ...) at a constant environmental temperature (for example, room temperature) to a good product in a multilayer ceramic capacitor having a rated voltage (here, 16V). The change of the current 1 second value of the current component (i _line ) and the leakage current component (i _leak ) obtained by measuring the charging characteristic when charging is shown. In FIG. 2, the horizontal axis is an applied voltage, and the vertical axis is a one second value (a logarithmic value) of the current.

The data in FIG. 2 is represented by a power approximation equation as follows. When the current 1 second value in the current component i _line is y and the applied voltage V is x, the following equation (5) is a power approximation between them.

y = 6. 1E-11x ^{3.5E + 00} ... (5)

Similarly, when the current 1 second value in the leakage current component i _leak is y and the applied voltage V is x, the following equation (6) is a power approximation between them.

y = 2. 4E-15x ^{5.5E + 00} ... (6)

Thus, by substituting the value of x (applied voltage V) into the above-described formulas (5) and (6), the current component (i _line ) and the leakage current component when the applied voltage (V) is applied. The value of (i _leak ) can be approximated. In other words, using the above-described formulas (5) and (6), it is possible to approximately simulate the current component (i _line ) or the leakage current component (i _leak ) for each applied voltage (V). .

As can be seen from the graph of FIG. 2 and the above-described formulas (5) and (6), the current rising rate (i _leak ) of the leakage current component (i _leak ) is higher than the current rising rate (RI [i _line ]) of the current component (i _line ). RI [i _leak ]) is large. 2, the inclination (direction coefficient in the case of considering it as a straight line) in the characteristic curve of each current component i _line and i _leak shows the current rise rate RI.

Examining the charging characteristics of the capacitor on the basis of the second feature, it can be seen that in determining the capacitor's acceptance, the determination time can be shortened by increasing the applied voltage V. FIG. Hereinafter, the reason will be described in detail.

FIG. 3 shows an example of a result of simulating the charging characteristic of the virtual threshold capacitor at that voltage in the state where the applied voltage V is variously changed. This simulation is carried out as follows. In standards, such as JIS, the threshold value of pass / fail judgment is prescribed | regulated as an insulation resistance in the rated voltage (V _std ). First, the threshold value S _std of the leakage current component i _{leak at the} rated voltage V _std is calculated from the threshold value (insulation resistance), and the calculated threshold value S _std is described above (4). Is substituted into the variable (g) in the equation. Further, variables (a, b, c, f) of formulas (1) to (3) in the rated voltage V _std are obtained. Thus, the charging characteristic of the virtual threshold capacitor at the rated voltage V _std is simulated.

Next, the applied voltage (V) at the same time as set (hereinafter referred to as the voltage (V _a)) in which the voltage increases by a random amount from the rated voltage (V _std), the measurement target capacitor by the measurement and analysis Formulas (5) and (6) above are prepared in advance. Thereafter, the simulation of the current component (i _{line (a))} of the virtual threshold value capacitor in by inputting a voltage (V _a) to create 5 expression, voltage (V _a).

Next, the estimate by inputting a voltage (V _a) to create (6) formula, the voltage (V _a) the leakage current component (i _{leak (a))} of the virtual threshold value capacitors in. Leakage current component _{(i leak (a))} serves as the threshold (S _a), i.e., good or bad determination condition for determining good or bad in the voltage (V _a).

The leakage current component i _{leak (a)} of the virtual threshold capacitor is calculated as follows, for example. Here, a capacitor having a relationship shown in FIG. 2 in the characteristics of the voltage / current 1 second value between the leakage current component i _leak and the current component i _line is taken as an example, and the voltage V _a is set to 80V. The calculation method of the leakage current component i _{leak (a) in a case} is demonstrated.

In the insulation resistance test standardized as a capacitor acceptance criteria, at a rated voltage V _std (= 16 V), an insulation resistance value of 1.6 GΩ is a threshold for determining acceptance. According to this, the leakage current component i _{leak (std)} of the virtual threshold capacitor indicating the threshold value S _{std at the} rated voltage V _std is 10 nA.

On the other hand, in the capacitor which has the characteristic shown in FIG. 2, there exists a relationship shown by Formula (6) mentioned above between the 1 second value y of the leakage current component i _leak , and the applied voltage V. In FIG. According to this equation (6), it can be seen that the leakage current component (i _leak ) is proportional to 5.5 power of the applied voltage (V). Therefore, the voltage (V _a) the leakage current component in the case of a 80V _{(i leak (a))} is

i _{leak (a)} = 10nA × (80/16) ^5.5 = 69.9㎂

Can be calculated. However, in view of the measurement accuracy of the current meter, it is reasonable to set the leakage current component i _{leak (a} ) to 69 mA.

In this way, after calculating the current component (i _{line (a))} and the leakage current component of the virtual threshold value capacitor in the voltage _{(V a) (i leak (} a)) ( good or bad determination condition), these current components synthesized by, simulates the charging characteristics of the virtual threshold value capacitor in the voltage (V _a). In addition, the current component i _{cap (a)} does not need to be calculated because it is not used for acceptance judgment.

In Figure 3, the rated voltage (V _std) this indicates a simulation result of the charge characteristics at applying the rated voltage (V _std) (= 16V) with respect to the virtual threshold value capacitor assuming according to 16V in a multilayer ceramic capacitor state at the same time, it shows a simulation result of the charging characteristic of a state set in the applied voltage (V _a) for the same virtual threshold value capacitor to 80V.

In FIG. 3, the point A _std is a change point (hereinafter, referred to as a change from the second time domain t _line to the third time domain t _leak in the charging characteristic when the rated voltage V _std (= 16V) is applied). and represents the first is referred to as two-third time domain switching level), the points (a _a) is a voltage (V _a) (= 80V), second-third time domain switching level (a) of the charging characteristics at the time of the application It is shown.

Looking at the graph of Figure 3 in detail it can be understood that the following. When comparing the temporal positions of the second to third time domain conversion points A _std and A _a , the conversion point A _a is temporally faster than the conversion point A _std (that is, near the start of voltage application). .

This is based on the following reasons. As described above in the second aspect, the current rise rate RI is RI [i _line ] <RI [i _leak ]. Therefore, when the applied voltage V is raised, the current rise rate RI is increased in the second time region t _line . The degree of increase of current in the third time region t _leak is greater than the amount of rise of current. Therefore, when the applied voltage V is raised, the second-third time domain conversion point A is pushed toward the voltage application start time side. As a result, the conversion point A _a is temporally faster than the conversion point A _std .

After passing through the above-described steps, in this embodiment, by determining the result as follows, the time required for the determination is shortened. That is, in applying the application voltage (V _a) with respect to the measurement target state capacitor, by measuring the electric current immediately after the turning point (A _a) has elapsed, measure the leakage current component _{(i leak (a)).} Then, a leakage current measuring component _{(i leak (a)),} by comparing with a threshold (S _a), to determine acceptability of the object to be measured capacitor. When here, the leakage current component _{(i leak (a))} is less than the threshold (S _a) and is determined to be non-defective, whereas large, it is determined as defective.

In this case, as described above, the time for measuring the leakage current component (i _leak ) of the capacitor to be measured is shortened as the conversion point A _a becomes faster than the conversion point A _std , which is required for good quality judgment. The time to do is shortened. In addition, the conversion point A _a can be found from the charging characteristic of the simulated virtual threshold capacitor and can be calculated by calculation.

The time for measuring the leakage current component (i _leak ) of the capacitor to be measured can be shortened as the voltage (V _a ) is increased. However, there is _a risk that the capacitor will be damaged if the applied voltage Va exceeds the breakdown voltage of the capacitor to be measured. Therefore, the applied voltage (V _a) is preferably set to a value such that the capacitor will not be damaged by the breakdown voltage or less of the object to be measured capacitor.

In this way, the determination is made as necessary to determine whether the second-third time domain change point A _a is faster in time than the second-third time domain change point A _std . The time to do it can be shortened.

(Embodiment 2)

In the first embodiment, by setting the applied voltage (V _a) to as high as possible, a two-third time domain switching level (A _a) the second-time and the third time domain in a more rapid switching level (A _std), this As a result, the time required for the acceptance judgment was shortened. However, in the method of the first embodiment, the leakage current component _{(i leak (a))} with a threshold (S _a) based on the comparison it judges good or bad of the capacitor, in time the leakage current component of (i _{leak (a It is not} possible to determine whether or not until ₎ ) becomes measurable.

However, in the capacitor, the leakage current component (i _leak) is rises, the charging current is a leakage current component (i _leak) current component in the second half period of the second time domain (t _line) received a rise in the (i _line Slightly higher than). Therefore, the charging characteristics of the defective capacitors gradually deviate from the second half of the second time region t _line with respect to the charging characteristics of the good capacitors.

In this embodiment, focusing on such a thing, making a positive judgment is performed by detecting the rise of the current component (i _line ) in the latter half period of a 2nd time area | region t _line , and, thereby, shortening a determination time is aimed at. have.

Hereinafter, the quality determination method of this embodiment is demonstrated in detail. First of all, and at the same time simulating the charging characteristics of the virtual non-defective capacitors in the applied state, the applied voltage (V _b), the leakage current from the applied state component (i _{leak (b} the applied voltage (V _b) a _pre-set) ) Simulates the charging characteristic of the virtual threshold capacitor, which represents the threshold value S _b of the positive judgment. Applied voltage (V _b) the threshold value set in (S _b), the threshold value (S _b) representing the simulation method of the charging characteristics of the virtual threshold value capacitors in, and simulation method of a charging characteristic of a virtual non-defective capacitors embodiment in the first, the same as that described as a simulation method of setting and filling characteristics of the applied voltage (V _a) in the virtual threshold value capacitors, in which a description thereof will be omitted.

An example of the charging characteristic of a virtual good capacitor and a virtual threshold capacitor is shown in FIG. 4 is a charging characteristic of a multilayer ceramic capacitor of the applied voltage (V _b) with a threshold value (S _b) a, V _b = 80V, the threshold value (S _b) = rated voltage (16V) to a 69㎂.

As shown in FIG. 4, the charging characteristic of the virtual threshold capacitor increases in the current value based on the above-described characteristic deviation between the charging characteristic of the virtual good capacitor in the second half of the second time region (t _line ). This is already happening. In this embodiment, good or bad is determined by measuring this current value rise.

In such a good or bad judgment method, it becomes a problem whether a defect can be judged as much as the amount of current difference generate | occur | produces between the charging characteristic of a virtual good capacitor and the charging characteristic of a virtual threshold capacitor. This problem can be solved based on the measurement error of the current meter. In this embodiment, on the basis of such a point of view, it is possible to determine whether the charging characteristic (current value) of the virtual threshold capacitor differs by 10% or more from the charging characteristic (current value) of the virtual good capacitor. However, it goes without saying that depending on the measurement error of the current measuring device, the time point at which the current difference amount other than that differs may be regarded as the time at which the judgment can be made.

The point in time at which a difference of 10% occurs in the charging characteristic of both capacitors in the charging characteristic of the virtual good / virtual threshold capacitor of FIG. 4 is referred to as the time point B, and the virtual threshold capacitor at the time point B. The current value indicated by is taken as the threshold value S _c in the present embodiment. Then, the time point B becomes a time point earlier in time than the second-third time domain change point A _c of the virtual threshold capacitor.

After specifying the time point B and the threshold value S _c , the acceptance judgment is performed by measuring the charging characteristic of each measurement sample. At that time, if the measured current value at the point (B), and the measured current value and the threshold value (S _c) below is determined for the sample with a non-defective product, and conversely more than the threshold value (S _c), the sample Is determined to be a defective product.

In addition, requiring the addition good or bad is determined with a shortening of time required for the good or bad is determined in accordance with the first exemplary embodiment, when a highly configurable, like the applied voltage (V _b), with Embodiment 1 of the present embodiment The time to do it can be shortened.

The quality determination method of Embodiments 1 and 2 described above can be implemented by the quality determination device shown in FIG. 5. This pass / fail determination device includes a sample gripping portion (1) for holding a sample (U) made of a capacitor during measurement, a voltage applying portion (2) for applying an applied voltage (V) to the sample (U), The current measuring unit 3 for measuring the current of the sample U when the applied voltage V is applied, and the controller 4 for controlling the operations of the voltage applying unit 2 and the current measuring unit 3. And a judging section 5 for judging success or failure based on the measured current measured by the current measuring section 3.

This pass / fail determination device determines the pass / fail of the sample U in the determiner 5 based on the pass / fail determination method of the first to second embodiments.

By the way, in Embodiment 1 and 2 mentioned above, the applied voltage V was fluctuate | varied for adjustment of a charging characteristic. However, the charging characteristic can also be adjusted by adjusting the environmental temperature at the time of charging. Therefore, the second-third time-domain conversion point A can be accelerated in time by adjusting the environmental temperature (specifically, raising the temperature).

As described above, according to the present invention, it is possible to determine whether the product is in the shortest time. In addition, it is possible to relatively easily set various conditions that can determine whether or not to be successful in the shortest time. Thereby, for example, an optimal pass / fail determination condition may be set for each product lot. In addition, it is also possible to automatically set the operating conditions of the delivery determination device by providing the set determination condition to the delivery determination device.

Claims (7)

Approximate formulating an approximate expression representing the temporal change of each characteristic component after separating the electrical characteristics generated in the capacitor during charging into a plurality of characteristic components having different characteristic changes over time. An expression creating step; A determination and determination condition setting step of extracting a determination reference characteristic component which is a criterion for the determination of the acceptance of the capacitor from the plurality of characteristic components and setting the acceptance determination condition of the determination reference characteristic component based on the approximation equation; A determination step of determining whether or not the determination target capacitor is judged by combining the determination reference characteristic component included in the electrical characteristic during charging of the determination target capacitor obtained by the measurement with the acceptance determination condition. Way. The method of claim 1, wherein a current is used as the electrical characteristic. 2. The method of claim 1, wherein the setting judgment condition is a step of setting a determination threshold value of the determination reference characteristic component as the acceptance determination condition. The determination step is a step of determining whether or not the determination target capacitor is judged based on a comparison of the determination reference characteristic component extracted from the electrical characteristic obtained by the measurement of the determination target capacitor and the determination threshold value. Acceptance judgment method. The method of claim 3, wherein the approximation formulating step includes a plurality of current components including the leakage current component of the capacitor, which is different from the current change over time for the charging current generated in the capacitor during charging. After separating into steps, it is a step of creating an approximation equation representing the time change of each current component, The acceptance decision condition setting step is a step of setting the determination threshold value of the leakage current component based on the approximation formula after extracting the leakage current component as the determination reference characteristic component. The judgment step is a step of judging whether the capacitor to be judged is good or bad based on a comparison between the leakage current component included in the current at the time of charging the capacitor to be determined obtained by the measurement and the judgment threshold. Way. The method of claim 3, wherein the approximation formulating step includes a plurality of current components including the leakage current component of the capacitor, which is different from the current change over time for the charging current generated in the capacitor during charging. After separating into steps, it is a step of creating an approximation equation representing the time change of each current component, The step of determining whether or not the above-mentioned positive and negative judgment conditions is an estimated value of the charging current after estimating the charging current whose value changes under the influence of the fluctuation of the leakage current component occurring due to the product quality of the capacitor as the judgment reference characteristic component. And setting the determination threshold of based on the approximation equation, And the determination step is a step of determining whether the determination target capacitor is successful based on a comparison between the charging current of the determination target capacitor obtained by the measurement and the determination threshold value. The said approximation formula creation step is a step of preparing the said approximation formula on the conditions which can shorten a judgment determination time as much as possible, The acceptance determination condition setting step is a step of setting the acceptance determination condition of the determination reference characteristic component under the condition that the acceptance determination time can be shortened as much as possible. And the determination step is a step of measuring the electrical characteristics of the capacitor to be measured under conditions that can shorten the acceptance determination time as much as possible. The said approximation preparation step is a step of preparing the said approximation formula in the state which applied the substantial maximum voltage which can be applied to the measurement object capacitor, The pass / fail condition setting step is a step of setting pass / fail conditions of the judgment reference characteristic component in a state in which the substantial maximum voltage is applied to the measurement target capacitor. And the determining step is a step of measuring the electrical characteristics in the state where the substantial maximum voltage is applied to the capacitor to be measured.