JP2007271551A - Environmental testing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environmental testing device capable of prolonging the time, when there is condensation, or controlling to some extent, the time condensation is generated. <P>SOLUTION: This environmental testing device 1 for generating condensation on a test object 30, by alternately exposing the test object 30 to a low-temperature low-humidity environment and to a high-temperature high-humidity environment, having at least a ventilating means and a ventilation environment control means 10 can change at least one among the ventilation amount, wind velocity and wind direction to change by the ventilation environment control means 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an environmental test apparatus, and more particularly to an environmental test apparatus for investigating the influence of condensation on a test object.

For example, in winter, when an electronic device such as a mobile phone, a digital camera, or a video camera is used outdoors and it is brought indoors or in a car, condensation may occur on the electronic device. In addition, when an electronic device such as that described above is used outdoors during the winter season or the rainy season, condensation may occur on the electronic device.
As described above, electronic devices that are used both indoors and outdoors and electronic devices that are frequently used outdoors are often exposed to dew condensation.
Furthermore, in recent years, usage environments have been diversified, and there are examples in which electronic devices are used in an extremely humid environment such as a bathroom. Equipment used in such an environment is extremely exposed to condensation.

On the other hand, there is a concern that condensation may adversely affect the insulation properties and electrical characteristics of electronic devices. That is, failures due to condensation have been known for a long time.
In particular, in recent years, electronic devices have been miniaturized and high-density mounting has progressed, and the conductors have become finer. For this reason, when condensation occurs in the device, there is a danger that the conductors may be short-circuited due to condensation, or a part of the conductor may be corroded and disconnected.
Therefore, it is important to evaluate the influence of dew condensation as one of the performance evaluation of electronic devices.

As a reliability test of insulation deterioration due to condensation, a condensation cycle test as described in Non-Patent Document 1 is known.
The condensation cycle test is a test method in which changes due to condensation are advanced by rapidly changing the humidity condition and repeating the generation and drying of condensation for a certain amount of time.
As an environmental test apparatus that reproduces the above-described test method, there is an environmental test apparatus as disclosed in Patent Document 1.
The environmental test apparatus described in Patent Document 1 places a test object in a test chamber kept in a dry state, and blows wet air onto the test object.
In the environmental test apparatus described in Patent Document 1, it is not possible to change the air flow rate, wind speed, and wind direction of the humid air. Moreover, in the environmental test apparatus described in Patent Document 1, it is not possible to change the amount of air blown, the wind speed, and the wind direction for blowing the air to maintain the test chamber in a dry state.
JPCA standard JPCA-ET09 JP-A-5-164684

Since the environmental test apparatus disclosed in Patent Document 1 can artificially cause dew condensation on the DUT, it can test the influence of the DUT on the dew condensation.
However, the environmental test apparatus disclosed in Patent Document 1 has a problem that the time from when condensation occurs until the condensation disappears is short. Moreover, in the environmental test apparatus disclosed in Patent Document 1, there is a problem that the time from the occurrence of condensation to the disappearance of condensation is almost constant and cannot be controlled at all.
Accordingly, the present invention pays attention to the above-mentioned problems of the prior art, and an object thereof is to provide an environmental test apparatus capable of prolonging the time during which condensation occurs and controlling the time during which condensation occurs to some extent.

In order to solve the above-mentioned problems, the present inventors have examined a process when condensation can occur and a process when condensation disappears.
In other words, assuming that the test object is placed in a low-temperature and low-humidity environment, the test object is dried at low temperature, and then the high-temperature and high-humidity air is fed, the dew point in the environment where the surface temperature of the test object is placed Condensation is generated when the temperature is below. On the other hand, condensation occurs on the surface of the test object, and when the temperature of the test object reaches the dew point or higher, moisture starts to evaporate. When the temperature becomes the same as the ambient temperature, the condensation completely disappears.
Therefore, the time during which condensation is present depends on the amount of heat exchange from the environment to the DUT and condensed water. For this reason, the wind speed and the air volume have a great influence on the accuracy of repetition of the time when condensation is present and the drying time.

  Accordingly, the invention described in claim 1 is an environmental test apparatus that alternately exposes the DUT to a low-temperature and low-humidity environment and a high-temperature and high-humidity environment to cause dew condensation on the DUT, and at least a blowing means and a blowing environment control. And a configuration capable of changing at least one of the air flow rate, the wind speed, and the wind direction by the air blowing environment control means.

  In the environmental test apparatus of the present invention, at least any one of the air volume, the wind speed, and the wind direction can be changed by the air environment control means, so that the time and amount of condensed water can be controlled to some extent.

  The invention described in claim 2 is in contact with the DUT after satisfying predetermined conditions after changing the environment in which the DUT is placed from a low temperature and low humidity environment to a high temperature and high humidity environment. The environmental test apparatus according to claim 1, wherein the air blowing environment is changed so that the air volume is reduced.

  Here, the “predetermined conditions” may be determined as appropriate. For example, a certain period of time has elapsed since the environment was changed from low temperature and low humidity to high temperature and high humidity, and the temperature of the object under test is constant. (As a specific example, the temperature of the DUT approaches the dew point temperature in the environment, and the difference becomes a certain value or less). Specific values for time and temperature may be determined based on experiments.

  As the “temperature of the DUT” in the present application, it is preferable to take the surface temperature of the DUT from the relationship with the dew point temperature, but the present invention is not necessarily limited to this, and the situation Depending on the case, the internal temperature of the DUT may be taken.

According to the second aspect of the present invention, the dew condensation water can be present for a relatively long time.
That is, the amount of dew condensation increases as the DUT surface temperature is below the dew point temperature of the ambient temperature and the temperature difference increases. As described above, the condensation disappears when the temperature of the DUT becomes the same as the ambient temperature. Therefore, the smaller the amount of heat exchange with respect to the DUT, the longer the condensation is maintained. Therefore, when the air volume in contact with the DUT is small, condensation can exist for a long time.
However, if the wind speed of the environment surrounding the DUT is low, the change rate of the ambient temperature becomes slow, and the time for the DUT to follow the temperature of the surrounding environment decreases, so the time for the dew point or less is shortened. There is a problem that the condensation that occurs is reduced or the condensation does not occur at all.
Therefore, in the invention described in claim 2, after the environment in which the DUT is placed is changed from the low temperature and low humidity environment to the high temperature and high humidity environment, and after satisfying predetermined conditions, the DUT is contacted. The air volume was reduced. In the environmental test apparatus of the present invention, after changing the environment in which the DUT is placed from a low-temperature and low-humidity environment to a high-temperature and high-humidity environment, the air volume contacting the DUT is reduced after satisfying a predetermined condition. Therefore, after sufficient dew condensation has occurred on the DUT, the air volume in contact with the DUT is reduced. Therefore, dew condensation water can exist for a relatively long time.

  The invention described in claim 3 has a DUT temperature measuring means for measuring the temperature of the DUT, and is subject to the condition that the DUT temperature is close to the dew point temperature of the environment in which the DUT is placed. The environmental test apparatus according to claim 1, wherein the air blowing environment is changed so that the air volume in contact with the test object is reduced.

The environmental test apparatus of the present invention has a DUT temperature measuring means for measuring the temperature of the DUT, and the DUT is subject to the condition that the temperature of the DUT is close to the dew point temperature of the environment in which it is placed. Reduce the air volume in contact with
When the temperature of the DUT is close to the dew point temperature of the environment where the DUT is placed, the amount of condensation that adheres to the DUT is maximized. In the environmental test apparatus of the present invention, since the amount of air in contact with the test object is reduced on condition that the temperature of the test object is close to the dew point temperature of the environment where the test object is placed, the amount of condensation that adheres to the test object is reduced. Decrease air volume after maximum. Therefore, dew condensation water can exist for a relatively long time.

  The invention according to claim 4 has an environment change period for changing the environment and a condensation maintenance period for maintaining condensation, and at least one of the air flow rate and the wind speed in the condensation maintenance period is smaller than that in the environment change period. The environmental test apparatus according to any one of claims 1 to 3.

  In the environmental test apparatus of the present invention, at least one of the air flow rate and the wind speed during the dew condensation maintenance period is made smaller than that during the environment change period, so that heat transfer to the DUT after the dew condensation is generated is suppressed. Water can be present for a relatively long time.

  The invention according to claim 5 has a drying period for drying the DUT and a condensation maintaining period for maintaining condensation, and at least one of the air flow rate and the wind speed during the condensation maintaining period is smaller than that during the drying period. An environmental test apparatus according to any one of claims 1 to 4.

  In the environmental test apparatus of the present invention, at least one of the air flow rate and the wind speed during the dew condensation maintenance period is made smaller than the drying period during which the test object is dried, so that the heat transfer to the test object after condensation is generated is suppressed. Therefore, the dew condensation water can exist for a relatively long time.

  The invention described in claim 6 has a low-temperature and low-humidity adjustment tank that creates a low-temperature and low-humidity environment, a high-temperature and high-humidity adjustment tank that creates a high-temperature and high-humidity environment, and a test chamber in which a test object is installed. 6. The environmental test apparatus according to claim 1, wherein air is alternately blown from the low temperature and low humidity adjustment tank and the high temperature and high humidity adjustment tank to the test chamber.

  The environmental test apparatus of the present invention has a low-temperature and low-humidity adjustment tank that creates a low-temperature and low-humidity environment, and a high-temperature and high-humidity adjustment tank that creates a high-temperature and high-humidity environment, and alternately blows air to the test chamber from these. Since it is a structure, the environment of a test room can be changed within a short time.

  Since the environmental test apparatus of the present invention can change at least one of the air flow rate, the wind speed, and the wind direction by the air blowing environment control means, it is possible to lengthen the time that condensation occurs or to control the time when condensation occurs to some extent. Can do. Therefore, the environmental test apparatus according to the present invention has an effect that the dew condensation condition required by the tester can be easily created.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a perspective view showing an internal structure of an environmental test apparatus according to an embodiment of the present invention. 2 and 3 are conceptual diagrams of an environmental test apparatus according to an embodiment of the present invention. FIG. 2 shows a state observed from the front side, and FIG. 3 shows a state observed from the side side including the control means. .

The environmental test apparatus 1 according to the present embodiment alternately exposes a test object to a low temperature and low humidity environment and a high temperature and high humidity environment to generate condensation on the test object.
The environmental test apparatus 1 of the present embodiment includes an entire tank 3 surrounded by a heat insulating material 2, and the inside of the entire tank 3 is a device placement room (test room) 5, a low-temperature and low-humidity adjustment tank 6, and a high-temperature and high-temperature tank. It is divided into a humidity control tank 4.
And the environment in the whole tank 3 is controlled by the control apparatus 10.

  As described above, the entire tank 3 has a function of arbitrarily adjusting the internal environment such as the internal temperature and humidity, as is well known. First, a schematic configuration of the entire tank 3 and means for adjusting the environment in the entire tank 3 will be described.

  The interior of the entire tank 3 is partitioned into at least three chambers by a partition plate 9 and a partition wall 13. That is, there is a DUT placement chamber (test chamber) 5 in which a DUT is placed at the upper part of the whole tank 3, and a low-temperature and low-humidity adjustment tank 6 through the partition plate 9 at the lower part of the whole tank 3. Further, a high-temperature and high-humidity adjusting tank 4 is provided via a partition wall 13 on the back side of the DUT placement chamber (test chamber). A door 14 for taking in and out the DUT is provided on the front surface of the DUT placement chamber (test room) 5.

  A machine room 34 is provided on the back side of the low-temperature and low-humidity adjustment tank 6 through a partition wall 33, and devices (not shown) such as a control device, a refrigerant circulation pump or a compressor are provided. However, the partition wall 33 and the machine room 34 may not be provided.

  In the embodiment shown in FIGS. 1 to 3, a high temperature and high humidity adjustment tank 4 is provided on the back side of the DUT placement chamber (test room) 5, and a low temperature and low humidity adjustment tank is provided below the DUT placement chamber 5. 6 are provided, but these arrangements may be changed as appropriate. For example, the low temperature and low humidity adjustment tank 6 may be provided on the back side of the DUT placement chamber (test room) 5, and the high temperature and high humidity adjustment tank 4 may be provided below the DUT placement room 5.

A room temperature detection sensor 11 and a humidity detection sensor 12 are provided in the DUT placement chamber 5.
The indoor temperature detection sensor 11 is specifically a thermocouple.
The detection signals of the indoor temperature detection sensor 11 and the humidity detection sensor 12 are input to the control device 10 (air blowing environment control means) as shown in FIG.

In the DUT placement chamber 5, a DUT temperature measuring sensor 36 for detecting the temperature of the surface of the DUT is provided.
As the DUT temperature measurement sensor 36, a known sensor such as a thermocouple or a thermistor can be used. The DUT temperature measuring sensor 36 detects the temperature of the DUT as described above, and it is recommended that it be directly attached to the DUT, but the temperature of the DUT is measured in a non-contact state. It may be a thing.
The DUT temperature measurement sensor 36 is connected to the control device 10 by a signal line.

  The low-temperature and low-humidity adjustment tank 6 is separated from the partition plate 9 and is below the DUT placement chamber 5. The partition plate 9 has openings 7 and 8 communicating with the DUT placement chamber 5 on both sides. is there. One opening 7 functions as a suction side opening, and the other opening 8 functions as an opening for ventilation. Dampers 27 and 28 are provided in the openings 7 and 8, respectively. Each of the dampers 27 and 28 is opened and closed by an actuator (not shown).

A humidifier 15, an air cooling heat exchanger 16, a dehumidifying heat exchanger 17, a heater 18, and a blower 20 are disposed in the lower temperature and low humidity adjustment tank 6. The low-temperature and low-humidity adjustment tank 6 is provided with a temperature sensor and a humidity sensor (not shown).
As the humidifier 15, the air cooling heat exchanger 16, the dehumidifying heat exchanger 17 and the heater 18, all known ones can be adopted.

  In the present embodiment, a blower 20 that can arbitrarily change the rotation speed is employed. That is, the motor (not shown) for driving the blower 20 is a DC motor or an AC motor controlled by an inverter, and the rotation speed is variable.

  The humidifier 15, the air cooling heat exchanger 16, the dehumidifying heat exchanger 17, the heater 18, and the blower 20 are each connected to a driving device such as a relay, and a signal from the control device 10 as shown in FIG. 3. To work.

  In the environmental test apparatus 1 of the present embodiment, the inside of the low-temperature and low-humidity adjustment tank 6 is always maintained in a predetermined low-temperature and low-humidity environment. That is, the air in the low-temperature and low-humidity adjustment tank 6 is circulated by the blower 20 and passes through the low-temperature and low-humidity adjustment tank 6 to create a desired environment. That is, the air in the low-temperature and low-humidity adjustment tank 6 is circulated in the low-temperature and low-humidity adjustment tank 6 by the blower 20, and at this time, the air passes through the air cooling heat exchanger 16 and the dehumidifying heat exchanger 17. Further, the heater 18 is touched. Moreover, water vapor | steam is supplied from the humidifier 15 as needed.

  When the dampers 27 and 28 are opened, the air in the low-temperature and low-humidity adjustment tank 6 is introduced into the DUT placement chamber 5. That is, when the dampers 27 and 28 are opened, air in the DUT placement chamber 5 is sucked into the low temperature and low humidity adjustment tank 6 from the suction side opening 7, and the DUT placement chamber 5 contains the air in the low temperature and low humidity adjustment tank 6. The air adjusted to low temperature and low humidity flows from the opening 8 for blowing. That is, the blower 20, the blower opening 8, etc. are blower means for blowing air adjusted to a low temperature and low humidity into the DUT placement chamber 5.

  The high-temperature and high-humidity adjustment tank 4 is on the back side of the DUT placement chamber 5, and has openings 7 ′ and 8 ′ communicating with the DUT placement chamber 5 above and below the partition wall 13. One opening 7 'functions as a suction side opening, and the other opening 8' functions as a blowing opening. Dampers 37 and 38 are provided in the openings 7 'and 8', respectively. Each of the dampers 37 and 38 is opened and closed by an actuator (not shown).

A humidifier 15 ', an air cooling heat exchanger 16', a dehumidifying heat exchanger 17 ', a heater 18' and a blower 20 'are also arranged inside the high temperature and high humidity adjusting tank 4.
The humidifier 15 ′ and other functions are the same as those arranged in the low-temperature and low-humidity adjustment tank 6 described above. The air cooling heat exchanger 16 ′, the dehumidifying heat exchanger 17 ′, and the heater 18 ′ Any known ones can be adopted.
Moreover, what can change rotation speed arbitrarily is employ | adopted for air blower 20 'in this embodiment. The humidifier 15 ′, the air cooling heat exchanger 16 ′, the dehumidifying heat exchanger 17 ′, the heater 18 ′, and the blower 20 ′ are each connected to a drive device such as a relay, and further, as shown in FIG. Operates in response to a signal from.

  In the present embodiment, the inside of the high-temperature and high-humidity adjustment tank 4 is always maintained in a predetermined high-temperature and high-humidity environment.

  When the dampers 37 and 38 are opened, the air in the high-temperature and high-humidity adjustment tank 4 is introduced into the DUT placement chamber 5. That is, when the dampers 37 and 38 are opened, the air in the DUT placement chamber 5 is sucked into the high temperature / high humidity adjustment tank 4 from the suction side opening 7 ′, and the DUT placement chamber 5 has the high temperature / high humidity adjustment tank 4. The air adjusted to high temperature and high humidity flows from the blowing opening 8 '. That is, the blower 20 ′, the blower opening 8 ′, etc. are blower means for blowing air adjusted to high temperature and high humidity to the DUT placement chamber 5.

  A setting input means 22 such as a numeric keypad or a touch panel is connected to the control device 10 of the environmental test apparatus 1 so that a desired environment in the entire tank 3 can be set and input. Moreover, the display means 23 is connected to the control apparatus 10, and the setting content and the environment in the whole whole tank 3 are displayed numerically. Moreover, the control apparatus 10 has a timer (not shown). An independent device may be used as the timer, or the control device 10 itself may have a timer function.

In the environmental test apparatus 1, the temperature and humidity in the DUT placement chamber 5 are monitored by the indoor temperature detection sensor 11 and the humidity detection sensor 12. When the temperature in the DUT placement chamber 5 is lower than the set environment temperature, the heater 18 (or 18 ') is energized to raise the temperature of the air, and the temperature in the DUT placement chamber 5 is set. When the temperature is higher than the environmental temperature, the refrigerant is passed through the air cooling heat exchanger 16 (or 16 ') to lower the temperature of the air cooling heat exchanger 16 (or 16'), and heat is circulated from the circulating air. Take away.
When the humidity in the DUT placement chamber 5 is lower than the humidity of the set environment, steam is injected from the humidifier 15 (or 15 ') and mixed into the passing air.
Conversely, when the humidity in the DUT placement chamber 5 is higher than the humidity in the set environment, the dehumidifying heat exchanger 17 (or 17 ′) condenses the water vapor.

  Next, functions of the environmental test apparatus 1 according to the present embodiment will be described in accordance with actual test procedures with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing the operation of the environmental test apparatus of this embodiment. FIG. 5 is a time chart showing changes in temperature, wind speed, and condensation amount in the environmental test apparatus of the present embodiment. In FIG. 5A, the environmental temperature in the test room is indicated by a broken line, and the temperature of the device under test is indicated by a solid line. FIG. 5B shows the set wind speed in the test room, and FIG. 5C shows the amount of condensation on the surface of the test object.

  The environmental test apparatus 1 of the present embodiment inspects, for example, a substrate 30 of a mobile phone as a device under test, and sets test conditions as a test preparation stage. That is, as described above, the environmental test apparatus according to the present embodiment alternately exposes the test object to a low temperature and low humidity environment and a high temperature and high humidity environment to cause condensation on the test object. Environment and high temperature and high humidity environment.

  Further, since the environment of low temperature and low humidity and the environment of high temperature and high humidity are repeated, the period and the time for keeping the environment constant are set.

  Subsequently, a substrate 30 as a test object is installed in the test object placement chamber 5. Specifically, the substrate 30 is placed in the DUT placement chamber 5. A DUT temperature measuring sensor 36 provided in the DUT placement chamber 5 is attached to the substrate 30.

  When the preparation is completed, the environmental test apparatus 1 is activated and the test is started. Hereinafter, the environmental test apparatus 1 functions like the flowchart of FIG. 4 and the time chart of FIG.

That is, when the environmental test apparatus 1 is activated, the temperature control function and the like of the low temperature and low humidity adjustment tank 6 and the high temperature and high humidity adjustment tank 4 start operation in steps 1 and 2. Specifically, the humidifier 15, the air cooling heat exchanger 16, the dehumidifying heat exchanger 17, and the heater 18 in the low temperature and low humidity adjustment tank 6 are activated and the environment in the low temperature and low humidity adjustment tank 6 is set. Try to get close to low temperature and low humidity. Similarly, the humidifier 15 ′, the air cooling heat exchanger 16 ′, the dehumidifying heat exchanger 17 ′, and the heater 18 ′ of the high-temperature and high-humidity adjustment tank 4 are activated to set the environment in the high-temperature and high-humidity adjustment tank 4. Try to get close to the high temperature and high humidity environment.
At this time, the rotation of the fans 20 and 20 'in each tank is started, and the rotation speed of the fans 20 and 20' at this time is full rotation.

  In step 3, the system waits for the environment in which the high temperature / high humidity adjustment tank 4 and the low temperature / low humidity adjustment tank 6 are set.

Then, in the subsequent step 4, the air adjusted to the low temperature and low humidity in the low temperature and low humidity adjustment tank is introduced into the DUT placement chamber 5.
Specifically, the dampers 27 and 28 provided in the openings 7 and 8 of the low-temperature and low-humidity adjustment tank are opened. At this time, the dampers 37 and 38 provided in the openings 7 'and 8' of the high-temperature and high-humidity adjusting tank are closed. As a result, air in the DUT placement chamber 5 is sucked into the low-temperature and low-humidity adjustment tank 6 from the suction-side opening 7, and air adjusted to low-temperature and low-humidity in the low-temperature and low-humidity adjustment tank 6 passes through the blower opening 8. It flows into the test article arrangement chamber 5. Here, the rotation speed of the blower at this time is full rotation, and air adjusted to low temperature and low humidity flows into the DUT placement chamber 5 with a large air volume and a high wind speed.
Therefore, the environment of the DUT placement chamber 5 rapidly decreases in temperature and humidity. The temperature of the DUT placed in the DUT placement chamber 5 also gradually decreases.

In step 5, it is confirmed that the inside of the DUT placement chamber 5 has become a predetermined low temperature and low humidity environment, and in step 6, the temperature of the DUT becomes a desired low temperature (TL in FIG. 5A). (Specifically, when it is confirmed that the difference between the temperature of the DUT and the ambient temperature in the test room is ± 1.0 ° C. or less), the process proceeds to Step 7 and the DUT High temperature and high humidity air is introduced into the placement chamber 5.
Note that the period from when the openings 7 and 8 of the low-temperature and low-humidity adjustment tank are opened until the temperature of the DUT reaches a desired low temperature is a drying period, during which the DUT is at a low temperature and in a dry state. That is, the condensation has disappeared.

  In this embodiment, the drying period is completed on the condition that the temperature of the DUT is confirmed to be a desired low temperature, but instead of this, or as a condition to be added to this, the low temperature and low humidity adjustment is performed. The time after opening the tank openings 7 and 8 and the time after the DUT placement chamber 5 becomes a predetermined low temperature and low humidity are measured, and the high temperature and the high temperature are set on condition that the predetermined time has passed. Wet air may be introduced.

The process after step 7 is an environment change period.
That is, in step 7, the openings 7 and 8 of the low-temperature and low-humidity adjustment tank are closed, and instead the openings 7 'and 8' of the high-temperature and high-humidity adjustment tank are opened.
As a result, the air adjusted to high temperature and high humidity flows into the DUT placement chamber 5 with a large air volume and high air speed. That is, the rotation speed of the blower at this time is full rotation. (The air volume and speed at this time are referred to as “large air volume” and “large wind speed”.)
Therefore, the environment of the DUT placement chamber 5 rapidly increases in temperature and humidity. In FIG. 5A, the environmental temperature is indicated by a broken line.

Here, since the DUT is cooled by the above-described drying process, the surface of the DUT becomes below the dew point temperature in the environment, and condensation rapidly occurs on the surface of the DUT.
Further, the temperature of the DUT gradually increases as shown by the solid line in FIG.

When it is detected in step 8 that the temperature of the surface of the test object has approached the dew point temperature in the environment (TW in FIG. 5A), the flow proceeds to step 9 to reduce the air flow rate.
Here, the state in which the surface temperature of the DUT is close to the dew point temperature in the environment means, for example, a state in which the difference between the two temperatures is ± 1.0 ° C. or less, and this is a state in which the amount of condensation is close to the maximum. is there.
In this embodiment, since the air flow rate is reduced in this state, the amount of air in contact with the DUT is reduced, and the amount of heat exchange between the DUT and the environment is reduced. Therefore, condensation will remain on the DUT for a long time. In FIG. 5A, the solid line graph is flat near TW. The air volume and speed at this time are referred to as “small air volume” and “small air speed”.

The temperature of the device under test gradually increases thereafter, and the condensation generated on the surface of the device under test gradually evaporates.
In this embodiment, after confirming that the test chamber is in a predetermined high-temperature and high-humidity environment in step 10, in step 11, the temperature of the object to be measured is the environmental temperature (the high-temperature side dry bulb temperature in FIG. 5A). When it is detected that the difference between the two temperatures has become ± 1.0 ° C. or less as the temperature approaches (TH), the process proceeds to step 12 to start the timer. This timer is adjusted to the time when condensation will remain. If it is determined in step 13 that the predetermined time has elapsed, the process proceeds to step 14 where the air flow rate is increased to a large air volume. As a result, the condensation on the surface of the test object disappears completely.

  In this embodiment, a timer is used and the air flow rate is increased on the condition that the timer has finished counting. However, the air flow rate is changed on the condition that the temperature of the DUT rises in place of or in addition to the timer. May be increased.

  In steps 15 and 16, high-temperature and high-humidity air is blown with a large air volume until a predetermined time elapses. When a predetermined time elapses, the one-cycle condensation process is finished. Then, the process proceeds to step 17 and 1 is added to the counter. In step 18, it is determined whether the number of counters has reached a preset number of repetitions. When the predetermined number of repetitions has been reached, the test is terminated. On the other hand, if the number of repetitions is not reached, the process returns to step 3 to repeat the previous process.

  Specific set temperatures, timer times, and the like in the above steps may be determined as appropriate based on experiments. The air volume and the wind speed may be determined appropriately, but the above-mentioned “large wind speed” is recommended to be 1.0 to 3.0 m / s, and the “small wind speed” is recommended to be 0.1 to 1.0 m / s.

  4 and 5 are merely examples, and it is needless to say that steps may be added, changed, or deleted as appropriate in an actual test.

In the embodiment described above, the air flow rate is adjusted by changing the rotation speed of the motors of the blowers 20 and 20 ′. However, a damper or the like may be provided, and the air flow rate may be increased or decreased by adjusting the opening degree of the damper. Is possible.
Further, a wind direction plate or the like for controlling the direction of the wind may be provided, and the actual air volume contacting the DUT (substrate 30 or the like) may be increased or decreased by changing the wind direction.

  Further, a wind speed sensor may be further provided in the DUT placement chamber 5, and the rotational speed of the motor and the opening degree of the damper may be controlled while monitoring the wind speed detected by the wind speed sensor.

  Moreover, it is good also as a structure which detects the wind speed of the wind which contacts the board | substrate 30 directly, the wind speed or the air quantity of the surface direction of the board | substrate 30, by devising the position, direction, and number of a wind speed sensor.

  In the embodiment described above, the air flow rate is changed in two stages, but it may be changed in stages in three or more stages. Moreover, you may increase / decrease ventilation volume not only according to a step change but according to deviation with target quantity. That is, the air flow rate and the wind speed may be proportionally controlled according to the temperature of the substrate 30.

  In addition, the above-described embodiment includes a low-temperature and low-humidity adjustment tank that creates a low-temperature and low-humidity environment, a high-temperature and high-humidity adjustment tank that creates a high-temperature and high-humidity environment, and a test chamber in which a test object is installed. Although the air is alternately blown from the low-humidity adjustment tank and the high-temperature and high-humidity adjustment tank to the test chamber, as another embodiment, the test object is between the low-temperature and low-humidity adjustment tank and the high-temperature and high-humidity adjustment tank. It may be moved.

The test was conducted by the operation method shown in FIGS. 4 and 5 using the environmental test apparatus shown in FIGS. Specifically, a comb substrate (0.3 mm pitch) is used as the DUT, the high-temperature environment temperature is 25 ° C., the high-temperature environment humidity is 90%, the low-temperature environment temperature is 5 ° C., and the low-temperature environment humidity is 60%. The test was conducted by repeatedly exposing the test object to the high temperature side environment and the low temperature side environment for 20 minutes each with the above large wind speed of 1.0 m / s and the small wind speed of 0.5 m / s.
When the voltage (DC5V) is applied and the leakage current during drying is more than twice the initial value, it is judged as a failure, and the cycle number and cumulative failure rate are plotted on the Weibull probability graph. was gotten.
This is thought to be due to the fact that the time when condensation is present and the repetition of the drying time are accurate. Therefore, it is expected that the accuracy of the evaluation of the influence due to condensation is improved.

It is a perspective view which shows the internal structure of the environmental test apparatus of embodiment of this invention. It is front sectional drawing which shows the structure of the environmental test apparatus of embodiment of this invention. It is side surface sectional drawing which shows the structure of the environmental test apparatus of embodiment of this invention. It is a flowchart which shows operation | movement of the environmental test apparatus of this embodiment. It is a time chart which shows the change of the temperature in the environmental test apparatus of this embodiment, a wind speed, and the amount of dew condensation.

Explanation of symbols

1,50 Environmental test equipment 3 Overall tank 4 High-temperature high-humidity adjustment tank 5 DUT placement room (test room)
6 Low-temperature and low-humidity adjustment tank 10 Controller 11 Indoor temperature detection sensor 12 Humidity detection sensor 15, 15 ′ Humidifier 16, 16 ′ Air cooling heat exchanger 17, 17 ′ Dehumidification heat exchanger 18, 18 ′ Heater 20 , 20 'Blower 27, 28 Damper 30 Substrate (DUT)
36 DUT temperature measuring sensor (DUT temperature measuring means)
37, 38 damper

Claims (6)

  In an environmental test apparatus for subjecting a DUT to a low-temperature and low-humidity environment and a high-temperature and high-humidity environment to cause condensation on the DUT, it has at least a blowing means and a blowing environment control means. An environmental test apparatus characterized by being capable of changing at least one of an air flow rate, a wind speed, and a wind direction.   After changing the environment in which the DUT is placed from a low-temperature and low-humidity environment to a high-temperature and high-humidity environment, the air blowing environment is changed so that the air volume in contact with the DUT is reduced after satisfying the prescribed conditions. The environmental test apparatus according to claim 1.   It has a DUT temperature measuring means to measure the temperature of the DUT, and air is blown so that the air volume in contact with the DUT is reduced on condition that the temperature of the DUT is close to the dew point temperature of the environment where the DUT is placed. The environment test apparatus according to claim 1, wherein the environment is changed.   2. An environment change period for changing the environment and a condensation maintenance period for maintaining condensation, wherein at least one of the air volume and the wind speed in the condensation maintenance period is smaller than that in the environment change period. 4. The environmental test apparatus according to any one of 3.   A drying period for drying the test object and a dew condensation maintaining period for maintaining dew condensation, wherein at least one of the air flow rate and the wind speed during the dew condensation maintaining period is smaller than that during the drying period. 4. The environmental test apparatus according to any one of 4 above.   A low-temperature and low-humidity adjustment tank that creates a low-temperature and low-humidity environment, a high-temperature and high-humidity adjustment tank that creates a high-temperature and high-humidity environment, and a test chamber in which the DUT is installed. The environmental test apparatus according to claim 1, wherein the air is alternately blown from the adjustment tank to the test chamber.

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