JP2004177169A - Measuring apparatus for capacitor characteristics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring apparatus for capacitor characteristics capable of preventing variations in measurement values in the temperature differences between a capacitor and measuring terminals and controlling temperature by a simple structure at low costs. <P>SOLUTION: The capacitor characteristics measuring apparatus for measuring electrical characteristics by bringing the measuring terminals 5 and 6 into contact with the capacitor C is provided with a blowing fan (temperature control means) 10 for performing control in such a way that the temperature difference at a contact part at least at contact between the capacitor C and the measuring terminal 6 may lie within a prescribed range. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a characteristic measuring device configured to measure an electric characteristic by bringing a measuring terminal into contact with a capacitor.
[0002]
[Prior art]
Generally, when a good product or a defective product is selected by measuring a leakage current of a capacitor, a DC voltage is applied while a measuring terminal is in contact with each electrode of the capacitor.
[0003]
In the case of such a measuring method, there is a problem that the measured value fluctuates due to, for example, self-heating of the capacitor. Therefore, as a method for preventing fluctuations in measured values, conventionally, for example, a method in which the temperature of an electronic component is adjusted by directly spraying a temperature-regulated gas whose temperature and air volume have been adjusted around the electronic component or on the electronic component has been adjusted. (For example, see Patent Documents 1 and 2).
[0004]
[Patent Document 1]
JP 2000-71746 A [0005]
[Patent Document 2]
JP 2000-171520 A
[Problems to be solved by the invention]
However, a method of simply adjusting the temperature of an electronic component or its surrounding temperature, as in the above-described conventional method, tends to cause a change in the measured value, particularly when measuring the leakage current of a capacitor. There is a problem that cannot be measured accurately.
[0007]
In addition, in the case of the above-described conventional method, equipment for cooling or heating the air based on the temperature data from the temperature sensor and a control mechanism for performing temperature control are required, and there is a problem that the cost is increased. .
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional circumstances, and has as its object to provide a capacitor characteristic measuring device capable of preventing a fluctuation of a measured value when measuring a capacitor leakage current with a low-cost and simple structure. And
[0009]
[Means for Solving the Problems]
The inventors of the present invention have studied the cause of the fluctuation in the measured value of the leakage current of the capacitor, and have found that the temperature difference between the capacitor C and the measurement terminal T is caused as shown in FIG. That is, when the measuring terminal T is brought into contact with the capacitor C in a state where a temperature difference occurs between the capacitor C and the measuring terminal T, heat is transferred between the two. Generally, a capacitor has a capacitance value characteristic according to a temperature, and therefore, the capacitance value also changes according to a temperature change of the capacitor. If a DC voltage is applied while heat transfer occurs between the measurement terminal T and the capacitor C, the leakage current is measured while the capacitance of the capacitor is changing. It is considered that the transfer of the charge of the capacitor occurs at this time, and as a result, the correct leakage current cannot be measured. This tendency is particularly remarkable when measuring a small leakage current of the capacitor at high speed and continuously.
[0010]
Therefore, an invention of claim 1 is a capacitor characteristic measuring device which measures an electrical characteristic by bringing a measuring terminal into contact with a capacitor, wherein a temperature difference at the time of contact between the capacitor and the measuring terminal is measured. It is characterized by comprising a temperature management means for managing the temperature within a predetermined range.
[0011]
Here, performing the temperature control means, as shown in FIG. 8, for example, using a blower mechanism 20 to cool or heat the contact portion between the capacitor C and the measurement terminal T, and to change the contact portion between the two. That is, the temperatures are set to be substantially the same, and a gas, a liquid, or the like can be used as a medium for performing the temperature management.
[0012]
A second aspect of the present invention is characterized in that, in the first aspect, the temperature management means manages the temperature difference by blowing air toward a contact portion between the capacitor and the measurement terminal by a blower fan.
[0013]
The invention of claim 3 is characterized in that, in claim 1 or 2, the temperature management means manages the temperature difference within a range of 0.1 to 3 degrees.
[0014]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the temperature management means manages the air blowing speed at least according to a capacitance value of the capacitor and a contact time. In this case, specifically, as the capacitance value of the capacitor is larger and the contact time is shorter, the blowing speed is increased.
[0015]
Effects of the Invention
According to the characteristic measuring device of the first aspect of the present invention, the temperature is controlled such that the temperature difference between the contact portion of the capacitor and the measuring terminal is within a predetermined range. In addition, a change in the capacity of the capacitor due to heat transfer can be suppressed. As a result, the leakage current of the capacitor can be accurately measured.
[0016]
According to the second aspect of the present invention, the temperature difference is controlled by blowing air to the contact portion by the blower fan. Therefore, the temperature difference between the two can be reduced with a simple structure, and the conventional temperature sensor, cooling, A heating device or a temperature control device can be dispensed with, and the temperature can be controlled with a low-cost and simple structure.
[0017]
According to the third aspect of the present invention, since the temperature difference is controlled to be in the range of 0.1 to 3 degrees, the transfer of heat can be almost eliminated, and the temperature difference between the two can be controlled to be smaller. Even in the case of a capacitor having a large capacity, the leakage current can be managed accurately.
[0018]
According to the fourth aspect of the present invention, since the blowing speed is controlled according to the capacitance value and the contact time of the capacitor, the temperature difference between the two can be controlled to be smaller, and the measurement accuracy can be further improved.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0020]
FIG. 1 and FIG. 2 are schematic configuration diagrams for explaining a capacitor characteristic measuring device according to a first embodiment of the present invention.
[0021]
The characteristic measuring device 1 of the present embodiment transports the capacitor C to the measuring unit 4 by intermittently rotating the four-table multi-purpose transport table 3 disposed on the front surface 2a of the fixed table 2, and transports the capacitor C to the measuring unit 4. The measuring unit 4 measures the leakage current of the capacitor C to select a non-defective product from a non-defective product, and then conveys the capacitor C to the component take-out unit 9 and discharges the capacitor C to the outside. In FIG. 1, reference numeral 11 denotes a work input hopper, 12 denotes a work distribution / transport unit, and 13 denotes a work transfer unit.
[0022]
Storage portions 3a for storing the capacitors C are formed at predetermined intervals in the circumferential direction on the transport table 3, and the capacitors C supplied into the storage portions 3a are positioned and held by vacuum suction (not shown). I have. The capacitor C is a chip type in which electrodes are formed on both end surfaces of a rectangular parallelepiped ceramic body, and is housed and arranged so that the electrodes face forward and backward.
[0023]
A fixed terminal 5 is disposed at a portion of the fixed table 2 facing the measuring section 4, and a movable terminal 6 is disposed in front of the fixed terminal 5 with the transport table 3 interposed therebetween so as to be able to advance and retreat. A DC voltage source 7 and a leakage current detection circuit 8 are connected to the movable terminal 6 and the fixed terminal 5.
[0024]
When the capacitor C is conveyed onto the fixed terminal 5 of the measuring section 4, the movable terminal 6 moves forward and contacts the front electrode of the capacitor C, and presses the rear electrode against the fixed terminal 5. In this state, a DC voltage is applied to measure the leakage current.
[0025]
The measurement unit 4 is provided with a blower fan 10 as a temperature management unit. The blower fan 10 is disposed toward the transfer table 3 on the front side of the transfer table 3, that is, on the side where the movable terminals 6 are installed, and sends cooling air from the blower fan 10 to the condenser C and the movable terminal 3 in particular. Spray toward 6. In this case, the wind speed and air volume are adjusted so that the temperature difference between the contact portion between the capacitor C and the movable terminal 6 is in the range of 0.1 to 3 degrees.
[0026]
Here, the fixed terminal 5 and the rear electrode of the capacitor C come into contact at the same time when the capacitor C is conveyed to the measuring section 4 and the movement of heat starts between the two, so that the movable terminal 6 moves forward. Thus, the temperature difference between the fixed terminal 5 and the capacitor C before contacting the front electrode of the capacitor C becomes so small that it can be almost ignored. That is, the heat transfer due to the temperature difference is greatest at the moment when the measuring terminal comes into contact with the capacitor, and thereafter, the heat transfer decreases with time and decreases. In addition, it is more effective to blow the cooling air to the contact portion between the capacitor C and the fixed terminal 5.
[0027]
In order to measure the leakage current of the capacitor C by the present embodiment, first, the blower fan 10 is driven to rotate to blow cooling air, and in this state, the capacitor C is transported to the measuring unit 4 by the transport table 3. When the rear electrode of the capacitor C contacts the fixed terminal 5, the movable terminal 6 moves forward and contacts the front electrode. In this state, a DC voltage is applied to measure the leakage current. During this series of operations, the contact portion between the capacitor C and the movable terminal 6 is particularly cooled by the cooling air from the blower fan 10, and the temperature difference between the two is reduced.
[0028]
As described above, according to the present embodiment, the temperature of the condenser C and the movable terminal 6 is controlled by the cooling air of the blower fan 10 so that the temperature difference between the two is within the range of 0.1 to 3 degrees. Therefore, the temperature difference between the capacitor C and the movable terminal 6 can be made extremely small, and a change in the capacitance of the capacitor due to transfer of heat can be suppressed. As a result, the measurement accuracy of the leakage current of the capacitor C can be improved.
[0029]
Since the structure in which the cooling fan is blown by the blower fan 10 to minimize the temperature difference between the capacitor C and the movable terminal 6 is adopted, the temperature can be controlled with a simple structure simply by adding the blower fan 10. The cost can be reduced as compared with the case where a conventional temperature sensor, a cooling / heating device, or a temperature control device is used.
[0030]
In the present embodiment, since the temperature difference between the contact portions of the capacitor C and the movable terminal 6 is controlled in the range of 0.1 to 3 degrees, the minute leakage current of the capacitor C is measured at high speed and continuously. It is effective in the case.
[0031]
Further, the blowing speed and the blowing amount may be controlled according to the capacitance value and the contact time of the capacitor C. In this case, the temperature difference between the two can be controlled to be smaller, and the measurement accuracy is further improved. it can.
[0032]
FIG. 3 is a diagram illustrating the results of an experiment performed to confirm the effects of the device according to the present embodiment. In this experiment, a large number of capacitors were measured continuously, cooling air was blown at a predetermined wind speed by a blower fan, and the current value at the start of measurement was measured. Was measured. For comparison, current fluctuations were measured in the same manner when circulating air was cooled to control the temperature around the capacitor and when cooling was not performed.
[0033]
As is apparent from FIG. 6, when the cooling is not performed, the fluctuation of the current value exceeding 40% occurs after 10 minutes. In the case of circulating air cooling, a change in current value of about 15% occurs after 10 minutes. On the other hand, in the present embodiment, the current value fluctuates by about 5% even after 10 minutes have passed, and it can be seen that the accuracy of the measured value is greatly improved by reducing the temperature difference.
[0034]
FIG. 4 is a characteristic diagram showing the relationship between the temperature difference between the capacitor and the measurement terminal and the wind pressure. This is achieved by using a characteristic measuring apparatus equipped with a 3.2 mm × 1.6 mm capacitor and a measuring terminal having a thermal resistance × heat capacity value of about 2, and setting the air flow rate of the blower fan 10 to 1 m ³ / min. In the characteristic measurement, the allowable temperature difference between the capacitor and the measuring terminal was examined. As a result, it was found that the allowable temperature difference was 1 ° C. for the 2.7 μF capacitor and 0.33 ° C. for the 10 μF capacitor.
[0035]
Also, a 10 μF capacitor was measured under the above conditions, and the temperature difference between the capacitor and the measurement terminal was measured by changing the wind pressure of the blower fan 10. As a result, it can be seen from FIG. 4 that the air pressure of the blower fan 10 needs to be about 24 Pa or more in order to measure a 10 μF capacitor without error.
[0036]
In the first embodiment, the case where the blower fan 10 is arranged on the front side of the transfer table 3 has been described. However, the blower fan 10 of the present invention is arranged on the side of the transfer table 3 as shown in FIG. It may be arranged.
[0037]
6 and 7 are views for explaining a characteristic measuring device according to the second embodiment of the present invention.
[0038]
In the characteristic measuring device of the second embodiment, storage recesses 15a for storing the capacitors C are formed at predetermined intervals in the circumferential direction on the outer peripheral edge of the transfer table 15, and a pair of measurement terminals are formed below the measurement unit 4. 16 and 16 are arranged so as to be able to move up and down, and a stopper 17 is arranged on the upper side. Then, each measuring terminal 16 is raised to push up the capacitor C, and at the same time, is pressed against the stopper 17, and in this state, a DC voltage is applied to measure the leakage current.
[0039]
An air pipe 18 is arranged in the measuring section 4. A blower fan (not shown) is connected to the blower tube 18, and by blowing cooling air from the blower tube 18, the contact portion between the condenser C and each of the measurement terminals 16 is simultaneously cooled, and the temperature of both of them is reduced. I try to get rid of the difference.
[0040]
Also in the present embodiment, the temperature difference between the capacitor C and each of the measurement terminals 16 can be made extremely small, and the leakage current of the capacitor can be accurately measured as in the first embodiment.
[Brief description of the drawings]
FIG. 1 is an overall view of a capacitor characteristic measuring device according to a first embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of the characteristic measuring device.
FIG. 3 is a characteristic diagram showing the results of an experiment performed to confirm the effects of the embodiment.
FIG. 4 is a characteristic diagram showing the results of an experiment performed to confirm the effects of the embodiment.
FIG. 5 is a schematic configuration diagram showing a modification of the first embodiment.
FIG. 6 is a schematic configuration diagram of a characteristic measuring device according to a second embodiment of the present invention.
FIG. 7 is a sectional view taken along line IV-IV of the characteristic measuring device.
FIG. 8 is a diagram for explaining the operation and effect of the present invention.
FIG. 9 is a diagram for explaining a process of establishing the present invention.
[Explanation of symbols]
1 Characteristics measuring devices 5, 6 Fixed and movable terminals (measurement terminals)
10. Ventilation fan (temperature management means)
16 Measurement terminal 18 Air piping (Temperature control means)
C capacitor

Claims (4)

In a capacitor characteristic measuring device configured to measure an electrical characteristic by bringing a measuring terminal into contact with a capacitor, a temperature difference of a contact portion between the capacitor and the measuring terminal at least at the time of contact is set within a predetermined range. An apparatus for measuring characteristics of a capacitor, comprising a temperature management means for managing the temperature. 2. The capacitor characteristic measuring device according to claim 1, wherein the temperature management means manages the temperature difference by blowing air toward a contact portion between the capacitor and the measurement terminal by a blower fan. 3. The capacitor characteristic measuring device according to claim 1, wherein the temperature management unit manages the temperature difference within a range of 0.1 to 3 degrees. 4. The capacitor characteristic measuring device according to claim 1, wherein the temperature management means manages the air blowing speed according to at least a capacitance value and a contact time of the capacitor.

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