JP7118589B2 - Electronic component life prediction device and electronic component life prediction method - Google Patents

Description

TECHNICAL FIELD Embodiments of the present invention relate to an electronic component life prediction apparatus and an electronic component life prediction method.

It is known that electronic components such as electrolytic capacitors and LEDs deteriorate over time in various characteristics such as capacitance. Therefore, techniques have been proposed for predicting the life (service life) of electronic components in a short period of time.

When predicting the life of an electronic component, for example, the useful life and the like are verified by performing an accelerated deterioration test on the electronic component. In general, when performing accelerated deterioration tests in consideration of the warranty period and standards of electronic components, it is important to predict the service life of the electronic components under the actual usage environment.

JP 2013-44714 A JP 2012-132882 A

In recent years, with the extension of the life of electronic components (extension of service life), there is a need to conduct accelerated deterioration tests for thousands to tens of thousands of hours. For this reason, it takes a long time to predict the useful life of electronic components in recent years. In other words, in order to shorten the development period of electronic equipment on which electronic components are mounted, it is required to reduce the time required for predicting the life of electronic components.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electronic component life prediction apparatus and an electronic component life prediction method capable of predicting the life of an electronic component in a short time.

An electronic component lifespan prediction apparatus according to an embodiment includes a storage unit, a variation acquisition unit, and a lifespan calculation unit. The storage unit stores a correlation between variations in characteristic fluctuation amounts of the plurality of first electronic components after performing a combined load test in which a plurality of load factors are applied simultaneously and life spans of the plurality of first electronic components. do. The variation acquisition unit acquires variations in the amount of variation in the characteristics of the plurality of second electronic components after performing the combined load test. The service life calculation unit calculates the service life of the plurality of second electronic components based on the correlation stored in the storage unit and the variation in the obtained variation amount of the characteristics. Variation in the amount of characteristic variation in the plurality of first and second electronic components is a functional margin SN ratio that can be calculated as a desirable or small characteristic among static characteristics in quality engineering . Each of the plurality of first and second electronic components is an electronic component having common product specifications.

According to the present invention, it is possible to provide an electronic component life prediction apparatus and an electronic component life prediction method capable of predicting the life of an electronic component in a short time.

1 is a block diagram functionally showing the configuration of an electronic component life prediction apparatus according to an embodiment; FIG. FIG. 2 is a cross-sectional view of an electrolytic capacitor whose life is to be predicted by the life prediction device of FIG. 1 ; The figure which illustrated the result of the temperature accelerated deterioration test as a comparative example. FIG. 2 is a flow chart for obtaining a correlation approximation line applied by the life prediction device of FIG. 1; FIG. The figure which shows an example of the correlation approximation line of FIG. 2 is a flowchart for selecting load factors for a combined load test used by the life prediction device of FIG. 1; FIG. 3 is a diagram showing an example of test conditions for each load factor applicable to the electrolytic capacitor of FIG. 2; FIG. 3 is a diagram exemplifying the degree of impact on capacitance reduction for each load factor applicable to the electrolytic capacitor of FIG. 2 and usefulness when combined with other load factors; FIG. 3 is a graph showing an example of the influence of a single load factor applicable to the electrolytic capacitor of FIG. 2 on the decrease in capacitance; FIG. FIG. 3 is a graph showing an example of the degree of influence of a composite load factor applicable to the electrolytic capacitor of FIG. 2 on a decrease in capacitance; FIG. The figure which shows an example of the test conditions for every load factor applicable to LED. 2 is a flow chart for predicting the life of an electronic component by the life prediction device of FIG. 1;

Embodiments will be described below with reference to the drawings.
As shown in FIG. 1, an electronic component life prediction device 10 according to the present embodiment includes a correlation storage unit 11, a variation acquisition unit 12, a life calculation unit 13, a database 14, an influence determination unit 15, and the like. .

The correlation storage unit 11 stores the variation in characteristic fluctuation amount (functional margin SN ratio) in the plurality of first electronic components after the combined load test and the service life of the plurality of first electronic components. Store the correlation (correlation approximation line). A compound load test subjects an electronic component under test to multiple load factors simultaneously. On the other hand, the variation acquiring unit 12 acquires variations in characteristic variation amounts of the plurality of second electronic components after the composite load test is performed. Here, each of the plurality of first and second electronic components described above is an electronic component whose product specifications are common to each other. Electronic components with the same specifications (product standards).

A lifespan calculation unit 13 calculates the lifespan of the plurality of second electronic components based on the correlation stored in the correlation storage unit 11 and the variation in characteristic variation acquired by the variation acquisition unit 12. calculate. The database 14 stores various data necessary for predicting the life of electronic components. In order to select a load factor to be applied to the composite load test, the impact determination unit 15 determines the impact of a single load factor (each load factor) on the deterioration over time of the first and second electronic components. do. The configuration of each unit shown in FIG. 1, such as the correlation storage unit 11, the variation acquisition unit 12, and the life calculation unit 13, will be described in detail later.

As shown in FIG. 2, in the present embodiment, a lead-type electrolytic capacitor 20 is exemplified as the first and second electronic components applied to life prediction. The electrolytic capacitor 20 is a finite-life component widely used in industrial equipment for smoothing power supply circuits. The electrolytic capacitor 20 has a sleeve 21 , an aluminum case 22 , an element portion 23 , a sealing rubber 24 , aluminum leads 25 and lead wires 26 . If the electrolytic capacitor is of the surface mount type, the lead wire has a shape different from that shown in FIG.

As shown in FIG. 2, the element portion 23 is composed of an anode foil formed by etching the surface of an aluminum foil to increase the surface area and forming a thin oxide film with a high withstand voltage by chemical conversion treatment, and a cathode foil only by etching treatment. It is manufactured by inserting electrolytic paper between the foil and winding it into a cylindrical element. Further, the element part 23 is impregnated with an electrolytic solution, the element part 23 is placed in the aluminum case 22, and then the sealing rubber 24 is used for packing. After that, the outer surface of the aluminum case 22 is covered with a sleeve 21 with necessary indications such as rated values.

In the electrolytic capacitor 20 having such a structure, the electrolytic solution impregnated inside flows out from the periphery of the sealing rubber 24 due to deterioration over time, and the capacitance and the dielectric, which expresses the degree of electrical energy loss in the dielectric. Various properties such as tangent (tan δ) and leakage current are degraded. Here, FIG. 3 illustrates the results of an accelerated deterioration test (temperature accelerated deterioration test) in which temperature is applied as a single load factor to two types of electrolytic capacitors of different types. Assuming that the product has reached the end of its life when the rate of change in capacitance reaches, for example, -7% to -10%, FIG. ) is required.

Therefore, as described above, the electronic component life prediction apparatus 10 according to the present embodiment has a function capable of quickly predicting the life of an electronic component such as an electrolytic capacitor that deteriorates over time. there is First, with reference to FIGS. 4 to 6, a procedure for obtaining a correlation approximation line necessary for life prediction will be described.

As shown in FIG. 4, a plurality of types of electrolytic capacitors (first electronic components described above) are prepared (S [step] 1). The electrolytic capacitors to be prepared do not have to be limited in terms of model or size, but prepare those with common product specifications. For example, three to five electrolytic capacitors of three or more types are prepared.

Next, for each electrolytic capacitor, capacitance is measured as initial characteristics (S2). The initial properties are the properties before the combined load test. In addition, although the capacitance is exemplified as the characteristic of the electrolytic capacitor, the characteristic to be measured need not be limited to the capacitance. If there are a plurality of characteristics to be degraded, at least one of them should be limited and the initial characteristics of the specified characteristics should be measured. Also, the measurement environment is, for example, a normal temperature and normal humidity environment.

Subsequently, a combined load test is performed on each electrolytic capacitor whose initial characteristics have been measured (S3). A combined load test simultaneously applies multiple types of load factors (factors that cause degradation) to an electrolytic capacitor. This combined load test takes several tens of hours, which is shorter than the accelerated aging test that applies the temperature element as a single load factor (the above-mentioned temperature accelerated aging test, which required thousands of hours or more). Complete in exam time.

Next, after the composite load test is completed, capacitance is measured as various characteristics of each electrolytic capacitor (S4). The measurement environment in this case is, for example, normal temperature and normal humidity as in S2 (step 2). Next, the functional margin SN ratio is calculated for each electrolytic capacitor based on the characteristics measured before the composite load test and the characteristics measured after the composite load test (S5). In other words, the functional margin SN ratio indicating the fluctuation amount (capacitance) of the characteristics of each electrolytic capacitor before and after the composite load test is obtained.

The functional margin SN ratio can be calculated, for example, as a desired small characteristic among static characteristics in quality engineering, and the larger the SN ratio, the smaller the fluctuation amount (capacitance) of the characteristic described above. It is known that the SN ratio of such static characteristics is calculated using Equation 1 below. Here, "y _i0 " in Equation 1 is the initial characteristic, "y _i " is the characteristic after the load test, and "n" is the number of samples.

Finally, as shown in FIGS. 4 and 5, the correlation between the calculated functional margin SN ratio (variation in characteristic fluctuation amount for each electrolytic capacitor) and the life of the electrolytic capacitor (first electronic component) A correlation approximation line representing the relationship is generated with reference to the contents of the database 14 (S6). The correlation storage unit 11 stores the generated correlation approximation line.

The database 14 stores, for example, information on other electrolytic capacitors (other electronic components whose service life has been verified) that are different in model from the electrolytic capacitors prepared in S1 (step 1). However, the other electrolytic capacitor (other electronic component) of the different type is an electronic component having, for example, specifications common to or similar to the prepared electrolytic capacitor. The database 14 pre-stores, for example, the relationship between the service life and functional margin SN ratio of electrolytic capacitors of different types. Therefore, it is possible to obtain the approximate correlation line shown in FIG.

Next, referring to FIGS. 6 to 8, a processing procedure for selecting load factors applied to the composite load test of S3 (step 3) shown in FIG. 4 will be described. Similarly to step Sl shown in FIG. 4, first, as shown in FIG. 6, a plurality of types of electrolytic capacitors (first electronic components described above) are prepared (S11). Next, as in step S2 shown in FIG. 4, the initial characteristics of the plurality of electrolytic capacitors are measured (S12).

Furthermore, as shown in FIG. 7, load factors that affect the characteristics of the measurement object are listed. For each of the listed load factors, single load test conditions are developed based on limit points and specification values. In the composite load test, a load factor is applied within the range of conditions (below the limit points described above) that can maintain the physical properties of the constituent materials in the electrolytic capacitors (first and second electronic components described above). A single load test is performed in which a load corresponding to each load factor is applied to the electrolytic capacitor for, for example, several tens of hours under the above defined single load test conditions (S13). The single load test may be performed on a plurality of electrolytic capacitors or may be performed on one electrolytic capacitor.

Next, after the single load test is completed, capacitance is measured as various characteristics of each electrolytic capacitor (S14). It should be noted that the measurement environment is, for example, normal temperature and normal humidity, as in S2 (step 2). Next, the functional margin SN ratio is calculated for each electrolytic capacitor based on the characteristics measured before the single load test and the characteristics measured after the single load test (S15). In other words, the functional margin SN ratio indicating the fluctuation amount (capacitance) of the characteristics of each electrolytic capacitor before and after the single load test is obtained. The function margin SN ratio in this case is also obtained by calculating the SN ratio of the static characteristic (the SN ratio of the desired small characteristic) in quality engineering, for example, using Equation 1 described above.

Finally, based on the functional margin SN ratio calculated in S15 (step 15), the influence determination unit 15 determines the influence of each load factor on the electrolytic capacitor (S16). In other words, the influence degree determination unit 15 determines the amount of change in the characteristics of a plurality of electrolytic capacitors (first electronic components) after performing a single load test that gives one load factor as the load factor applied in the composite load test. selection based on the variation of Appropriate load factors to be combined and applied at the same time in the composite load test in S3 (step 3) shown in FIG.

FIG. 7 shows an example of test condition proposals drawn up with reference to, for example, the limits of constituent materials and standard values of electrolytic capacitors. Mechanisms of failure that reduce the capacitance of electrolytic capacitors include dry-up of the electrolytic solution, formation and hydration of the dielectric oxide film, and the like. For this reason, for example, temperature, humidity (e.g. 80% humidity for 50 hours), heat cycle, reverse voltage (e.g. -1.5 V to -2 V applied), overvoltage (e.g. 1.5 times the rated voltage applied) and the like are examples of load indexes (extraction factors).

Moreover, in the composite load test, the conditions for applying the load factor are appropriately selected for each electronic component from the environmental load factor and the electrical load factor. FIG. 8 shows the degree of influence of each load factor on the characteristics (capacitance) of the electrolytic capacitor, and the usefulness of combining each load factor with other load factors. Here, for each item (influence, usefulness of combination) in FIG. showing.

Further, FIG. 9 illustrates calculation results of the functional margin SN ratio (for each load factor) when a single load test is performed. FIG. 9 shows functional margin SN ratios calculated by giving load factors of temperature, humidity and reverse voltage to two types of electrolytic capacitors (parts A and B). Based on the results shown in FIG. 9, the influence determination unit 15 selects multiple load factors to be applied in the composite load test. For example, the plurality of selected load factors are selected from environmental load factors or electrical load factors. In FIG. 9, when the load factor is reverse voltage, the functional margin SN ratio is smaller than when the load factor is humidity, so it can be seen that the degree of influence on the decrease in the capacitance of the electrolytic capacitor is large. . Also, for example, reverse voltage is suitable in combination with temperature and can be applied simultaneously. Therefore, it is preferable to select temperature and reverse voltage as load factors to be applied simultaneously in the combined load test.

FIG. 10 shows an example of the results of a combined load test. As shown in FIG. 10, the combined load test with temperature and reverse voltage as load factors has a smaller functional margin SN ratio (gain) than the reliability test with the rated voltage and rated temperature as test conditions. Therefore, it can be judged to be suitable for obtaining the correlation approximation line shown in FIG.

FIG. 11 shows an example of test conditions for each load factor for a light emitting diode (LED). It is assumed that the loading factor selected for the electrolytic capacitor described above is different from the loading factor selected for the light emitting diode. In addition to the load factor selected for the electrolytic capacitor, the load factor selected for the light emitting diode may further include vibration, corrosive gas, light, etc., as shown in FIG.

Next, referring to FIG. 12, a procedure for predicting the life of the electrolytic capacitor (second electronic component) will be described. As shown in FIG. 12, a plurality of types of electrolytic capacitors (second electronic components described above) whose lifetimes are to be predicted are prepared (S21). For the electrolytic capacitors to be prepared, although there is no need to limit the type or size, for example, the specifications of the products should be common to each other. For example, three to five electrolytic capacitors of three or more types are prepared.

Next, in the normal temperature and humidity measurement environment where S2 (step 2) was performed, the capacitance is measured as an initial characteristic for each electrolytic capacitor (S22). The measurement environment in this case is, for example, normal temperature and normal humidity as in S2 (step 2). The initial properties are the properties before the combined load test. Next, a combined load test is performed on each electrolytic capacitor whose initial characteristics have been measured (S23). The combined load test at this time is performed under the same test conditions as S3 (step 3) shown in FIG.

Subsequently, after the composite load test is completed, the characteristics (capacitance) of each electrolytic capacitor are measured (S24). The measurement environment in this case is, for example, normal temperature and normal humidity as in S2 (step 2). Next, the functional margin SN ratio is calculated for each electrolytic capacitor based on the characteristics measured before the composite load test and the characteristics measured after the composite load test (S25). In other words, the variation acquisition unit 12 acquires the functional margin SN ratio representing the variation in the characteristic variation (capacitance) of each electrolytic capacitor (second electronic component) before and after the composite load test.

Finally, the life calculation unit 13, based on the correlation approximation line (correlation) shown in FIG. Lifespans of a plurality of electrolytic capacitors (second electronic components) are calculated.

As described above, in the electronic component life prediction device 10 and the electronic component life prediction method according to the present embodiment, the functional margin SN ratio in the composite load test and quality engineering that simultaneously apply a plurality of load factors is effectively By applying it, the life of electronic parts can be predicted in a short time with high accuracy.

Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and its equivalents.

DESCRIPTION OF SYMBOLS 10... Life prediction apparatus of an electronic component, 11... Correlation storage part, 12... Variation acquisition part, 13... Life calculation part, 20... Electrolytic capacitor.

Claims (8)

a storage unit that stores a correlation between variations in variation in characteristics of a plurality of first electronic components after performing a composite load test in which a plurality of load factors are applied simultaneously and life spans of the plurality of first electronic components; ,
a variation acquisition unit that acquires variations in variation amounts of characteristics of the plurality of second electronic components after the composite load test has been performed;
a lifespan calculation unit that calculates the lifespan of the plurality of second electronic components based on the correlation stored in the storage unit and the variation in the variation amount of the acquired characteristic;
with
Variation in the amount of variation in the characteristics of the plurality of first and second electronic components is a functional margin SN ratio that can be calculated as a desired or small characteristic among static characteristics in quality engineering ,
each of the plurality of first and second electronic components is an electronic component having common product specifications;
A device for predicting the life of electronic components. The load factor to be applied in the composite load test is selected based on variations in the amount of variation in the characteristics of the plurality of first electronic components after performing a single load test that gives one load factor.
The electronic component life prediction device according to claim 1 . In the composite load test, a load factor is applied within a range of conditions that can maintain the physical properties of the constituent materials of the first and second electronic components.
3. The electronic component life prediction device according to claim 1 or 2 . The combined load test is completed in a shorter test time than an accelerated aging test in which the temperature factor is applied as a single loading factor.
4. The electronic component life prediction device according to any one of claims 1 to 3 . A storage unit stores a correlation between variations in characteristic fluctuation amounts in a plurality of first electronic components after performing a composite load test in which a plurality of load factors are applied simultaneously and life spans of the plurality of first electronic components. a step;
a step of obtaining variations in characteristic fluctuation amounts in a plurality of second electronic components after performing the composite load test;
a step of calculating the service life of the plurality of second electronic components based on the correlation stored in the storage unit and the variation in the variation amount of the acquired characteristic;
has
Variation in the amount of variation in the characteristics of the plurality of first and second electronic components is a functional margin SN ratio that can be calculated as a desired or small characteristic among static characteristics in quality engineering ,
each of the plurality of first and second electronic components is an electronic component having common product specifications;
A method for predicting the life of electronic components. A step of selecting a load factor to be applied in the composite load test based on variations in characteristic fluctuation amounts in the plurality of first electronic components after performing a single load test giving one load factor;
The method for predicting the life of an electronic component according to claim 5 , further comprising: In the composite load test, a load factor is applied within a range of conditions that can maintain the physical properties of the constituent materials of the first and second electronic components.
7. The life prediction method for an electronic component according to claim 5 or 6 . The combined load test is completed in a shorter test time than an accelerated aging test in which the temperature factor is applied as a single loading factor.
The life prediction method for an electronic component according to any one of claims 5 to 7 .

Images