JP3212716B2 - Test sample temperature attainment determination method and exposure mode switching control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mainly used for environmental tests such as a thermal shock test for exposing a specimen such as an electronic component to high and low temperature air to test the reliability of the specimen against a temperature change stress. In particular, the present invention relates to a method for determining a specimen temperature attainment in an environmental test and an exposure mode switching control device.

[0002]

2. Description of the Related Art Conventionally, in order to test the reliability of electronic components and printed circuit boards on which electronic components, etc. are mounted, against the stress caused by temperature changes, the test samples are alternately exposed to high-temperature and low-temperature air. Environmental tests such as impact tests have been conducted.

FIG. 7 is a diagram showing a temperature transition in a conventional thermal shock test. In the figure, T _C is the test tank temperature,
T _T is the specimen temperature, T _H is the set high-temperature exposure temperature, T
_L is the set low temperature exposure temperature.

In a conventional thermal shock test, a user sets a high-temperature exposure time T10 and a low-temperature exposure time T20 to a built-in timer, for example, so that a test sample is exposed to air at each temperature for a set time.

[0005]

However, in the actual thermal shock test, as shown in FIG. 7, the test sample must reach the set exposure temperature before the set exposure time T10 or T20 elapses. There are many. This is because the time setting has a margin. In this case, for example, between time t1 and t2 and between time t3 and t4, no temperature change stress is applied to the test sample, so that useless time is generated, and a long test time is required. Had become.

On the other hand, in order to check whether the specimen has reached the set exposure temperature, it is necessary to attach a temperature sensor directly to the specimen, but the work of attaching and detaching the temperature sensor is performed every test. This is very troublesome and is not preferable in terms of test efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a simple configuration to determine whether a specimen reaches a set temperature and to reduce the time required for an environmental test such as a thermal shock test. It is an object of the present invention to provide a method for determining a temperature attainment of a sample and an exposure mode switching control device.

[0008]

In order to achieve the above object, the present invention provides a test tank capable of accommodating a test sample and having a fluid inlet / outlet sandwiching the test sample; A fluid supply means for flowing a fluid at a predetermined temperature from the inlet to change the temperature to a preset temperature, and for flowing the fluid to the outside from the outlet; a test tank temperature detecting means provided in the test tank; In an environmental test apparatus provided with an outlet temperature detecting means provided, a time change rate of a temperature difference between both temperatures detected by each of the temperature detecting means is obtained, and the time change rate is compared with a predetermined value, and When the time change rate is equal to or less than the predetermined value, it is determined that the sample has reached the preset temperature (claim 1).

An environmental test apparatus capable of accommodating a test sample, having a test tank having a fluid inlet / outlet across the test sample, and performing an environmental test in a plurality of exposure modes.
A test tank temperature detecting means provided in the test tank, an outlet temperature detecting means provided at the outlet, and a temperature difference calculating means for calculating a temperature difference between both temperatures detected by the respective temperature detecting means, Rate-of-change calculating means for calculating the time rate of change of the calculated temperature difference; determining means for determining whether the calculated time rate of change is equal to or less than a predetermined value; and exposing mode when the time rate of change is equal to or less than the predetermined value. And switching means for switching between (1) and (2).

[0010]

According to the present invention, the temperature of the outlet of the test tank and the temperature of the test tank are detected. Then, when the time rate of change of the detected temperature difference between the two temperatures becomes equal to or less than a predetermined value, it is determined that the sample has reached the preset temperature.

According to the second aspect of the present invention, the temperature at the outlet of the test tank and the temperature in the test tank are detected, and the difference between the detected temperature at the outlet of the test tank and the temperature of the test tank is detected. The time rate of change is calculated. When the time rate of change becomes equal to or less than a predetermined value, the exposure mode is switched.

[0012]

FIG. 2 is a schematic configuration diagram of a thermal shock device as an example of an environmental test device to which the present invention is applied. The thermal shock device includes a high-temperature tank 1, a low-temperature tank 2, and a test tank 3 which are adiabatically partitioned, and a high-temperature tank partition 6a, a high-temperature inlet 6b, and a high-temperature outlet are provided between the high-temperature tank 1 and the test tank 3. 6c,
The low-temperature tank 2 and the test tank 3 can communicate with each other through a low-temperature inlet 6d and a low-temperature outlet 6e. The outside air inlet 6g and the outside air outlet 6f circulate air outside the apparatus in the normal temperature exposure mode. The shelf 4 is provided in the test tank 3, on which the specimen 5 is placed, and a thermal shock test is performed.

The high temperature bath heater 11 raises the temperature of the air in the high temperature bath 1. The fan 12 a
It stirs the air inside, and is always activated. As the fan 12b, a multi-blade fan or the like is used. The fan 12b sucks air in front (left side in the figure) and blows out the air toward the high-temperature inlet 6, so that it operates in the high-temperature exposure mode and the normal-temperature exposure mode. It has become.

The refrigerator 13 lowers the temperature of the air in the low-temperature tank 2. The low-temperature tank heater 14 is used for temperature control.
Is turned on and off to accurately and stably control the air temperature. In addition, low temperature bath heater 1
4 is also for defrosting the refrigerator 13. The regenerator 15 reduces the load on the refrigerator 13. As the fan 12c, a multi-blade fan or the like is used,
Suction of air in front (left side in the figure) and low-temperature inlet 6d
It blows out toward, and it is designed to operate constantly.

The dampers 16a to 16f have respective openings 6a to 6f.
The open / close state of g is switched to control the circulation of air in the thermal shock device. The damper 16a switches between opening and closing the high-temperature tank partition 6a and the outside air inlet 6g. In the high-temperature exposure mode, the high-temperature tank partition 6a is "open" (the outside air inlet 6g is "closed"), and the normal-temperature exposure mode. Alternatively, in the low-temperature exposure mode, the high-temperature tank partition 6a is closed (the outside air inlet 6g is open).

The damper 16b switches the opening and closing of the high-temperature inlet 6b. The damper 16b is "open" in the normal-temperature exposure mode or the high-temperature exposure mode, and is "closed" in the low-temperature exposure mode. The damper 16c switches the opening and closing of the high-temperature outlet 6c, and is configured to be "open" in the high-temperature exposure mode and "closed" in the normal-temperature exposure mode or the low-temperature exposure mode.

The damper 16d switches the opening and closing of the low-temperature inlet 6d. The damper 16d is "closed" in the normal-temperature exposure mode or the high-temperature exposure mode, and is "open" in the low-temperature exposure mode. The damper 16e switches the opening and closing of the low-temperature outlet 6e. The damper 16e is "closed" in the normal temperature exposure mode or the high-temperature exposure mode, and is "open" in the low-temperature exposure mode.

The damper 16f switches the opening and closing of the outside air outlet 6f, and is "open" in the normal temperature exposure mode.
In the low-temperature exposure mode or the high-temperature exposure mode, "close" is set.

FIG. 2 shows the state of each of the dampers 16a to 16f in the normal temperature exposure mode.

The high-temperature chamber temperature sensor 21 is disposed in the high-temperature chamber 1 and near the high-temperature outlet 6c, and detects the temperature of air circulating from the test chamber 3 in the high-temperature exposure mode. The high-temperature tank temperature sensor 21 detects the air temperature in the high-temperature tank 1 during the normal-temperature exposure mode or the low-temperature exposure mode so as to preheat the air.

The low temperature chamber temperature sensor 22 is disposed in the low temperature chamber 2 and near the low temperature outlet 6e, and detects the temperature of the air flowing out of the test chamber 3 in the low temperature exposure mode. Further, the low-temperature tank temperature sensor 22 detects the air temperature in the low-temperature tank 2 during the normal-temperature exposure mode or the high-temperature exposure mode in order to perform pre-cooling adjustment.

The test tank leeward temperature sensor 23 is disposed on the windward side (right side in the figure) of the air circulation in the test tank 3, and the test tank leeward temperature sensor 24 is leeward of the air circulation in the test tank 3. (In the figure, on the left side), each of which detects the air temperature in the test tank 3.

The leeward temperature sensor 23 of the test tank indicates a temperature comparable to the outlet temperature of the high temperature tank 1 or the low temperature tank 2, and the leeward temperature sensor 24 of the test tank rises and falls from that temperature by the amount of heat transferred to and from the specimen 5. Indicates temperature. Therefore, the test tank leeward temperature sensor 24 should indicate a temperature closer to the specimen 5 than the test tank leeward temperature sensor 23. Therefore, when controlling the temperature in the test tank 3, the test tank upstream temperature sensor 23 or the test tank downstream temperature sensor 24 is selected and used according to the purpose.

At an appropriate position on the surface of the thermal shock device, there is provided a display section for numerically or graphically displaying the conditions set by input, the temperatures of the tanks detected by the temperature sensors 21 to 24, the current cycle number, and the like. Is provided.

FIGS. 3A and 3B are schematic structural views of the thermal shock device showing the state of each of the dampers 16a to 16f and the direction of air circulation in the apparatus. FIG. 3A shows a high-temperature exposure mode state, and FIG. Is shown.

FIG. 1 is a block diagram showing a control structure of a thermal shock device as an example of an environmental test device to which the present invention is applied. The input means 31 is composed of ten keys and the like, and is used to set and input test conditions and the like for a thermal shock test. The thermal exposure temperature, the low temperature exposure temperature, the preheating (precooling) temperature of the high temperature chamber 1 (low temperature chamber 2), the thermal shock The number of cycles, 2 zones (high temperature exposure mode → low temperature exposure mode → high temperature exposure mode) or 3 zones selection (high temperature exposure mode → normal temperature exposure mode → low temperature exposure mode → normal temperature exposure mode → high temperature exposure mode) The selection of a sensor for detecting the temperature of the test tank 3 (the test tank windward temperature sensor 23 or the test tank windward temperature sensor 24), the time of each exposure mode, and the like are set.

The preheating (pre-cooling) temperature is slightly higher (lower temperature) than the set high-temperature exposure (low-temperature exposure) temperature in order to rapidly raise (fall) the temperature of the test tank 3 when the exposure mode is switched. I am trying to set it.

The sequence controller 33 receives a signal input from the discriminating means 326 described later, and
2a to 12c, dampers 16a to 16f, high temperature bath heater 1
1, to control the operation of the refrigerator 13, the low-temperature bath heater 14, and the like. Further, the sequence controller 33 operates the selecting means 321 and 322 described later according to the test mode to select a temperature sensor to be used.

The control section 32 is composed of a microcomputer or the like and controls the operation of the entire apparatus. The control section 32 has selection means 321 and 322, temperature difference calculation means 323, and storage means 3.
24, a change rate calculating unit 325, a determining unit 326, and the like.

The selecting means 321 outputs the output of the high temperature bath temperature sensor 21 in the high temperature exposure mode and the output of the low temperature bath temperature sensor 22 in the low temperature exposure mode to the temperature difference calculating means 323 according to the operation signal from the sequence controller 33. Is what you do.

The selecting means 322 outputs the output of the test tank windward temperature sensor 23 or the test tank leeward temperature sensor 24 selected by the input means 31 to the temperature difference calculating means 323 in response to an operation signal from the sequence controller 33. It is.

The temperature difference calculating means 323 is connected to the selecting means 32
The temperature difference between the temperatures input from the first and the second temperatures 322 is calculated for each sampling time. The calculated temperature difference is stored in the storage unit 324.

The change rate calculating means 325 includes a storage means 324
Is calculated from the temperature difference for each sampling time stored in.

The discriminating means 326 discriminates the magnitude of the time change rate from a predetermined value. When the time change rate becomes equal to or less than the predetermined value, a signal to that effect is sent to the sequence controller 33.
Output.

Next, the principle of determining that the temperature of the specimen 5 has reached the set exposure temperature will be described. 4A and 4B are diagrams showing the transition of the temperature change. FIG. 4A shows the high-temperature exposure mode state, and FIG. 4B shows the low-temperature exposure mode state. Here, T _C is selected test chamber 3 of the temperature sensor (test chamber windward temperature sensor 23 or the test chamber downstream temperature sensor 24) detected by the temperature of the test chamber 3, T _T is the thermal shock test carried out The sample temperature, T _HS is the temperature detected by the high temperature bath temperature sensor 21, T _H is the high temperature exposure temperature set as the test condition, T _LS is the temperature detected by the low temperature bath temperature sensor 22,
_TL is a low temperature exposure temperature set as a test condition.

Normally, the temperature sensor used in the thermal shock test is the temperature sensor of the test tank 3, but since it takes time to exchange heat with the specimen 5, FIGS. 4 (a) and 4 (b) As shown in the figure, the specimen temperature T _T rises or falls with a delay with respect to the temperature T _C of the test tank 3.

After the temperature T _C of the test tank 3 reaches the set exposure temperature _TH (or T _L ), the specimen temperature T _T is changed from the set exposure temperature _TH (or T _L ) to a temperature range ΔT. Have stable.

Here, the following contents have been clarified by experiments of the inventor. That is, the detected temperature _THS of the high-temperature tank temperature sensor 21 that has detected the temperature of the high-temperature tank 1 during the low-temperature exposure mode becomes the temperature shown in FIG.
As shown in (a), the temperature change is similar to the sample temperature T _T , and the detected temperature T _{LS of} the low-temperature tank temperature sensor 22 that has detected the temperature of the low-temperature tank 2 during the high-temperature exposure mode.
, When the cold exposure mode, as shown in FIG. 4 (b), is to show the same temperature transition and specimen temperature T _T.

This is because the high-temperature tank temperature sensor 21 and the low-temperature tank temperature sensor 22 are connected to the high-temperature outlet 6c and the low-temperature outlet 6e.
It is considered that the temperature of the air after the heat exchange with the sample 5 is detected, respectively, because the temperature is set in the vicinity of the sample.

Therefore, the detected temperatures T _HS and T _{LS of} the high temperature tank temperature sensor 21 and the low temperature tank temperature sensor 22 and the temperature T
The temperature difference ΔT between _C was made to determined to have reached a stable in time, the specimen temperature T _T is set exposure temperature T _H (or T _L).

Next, the procedure for determining that the temperature of the sample 5 has reached the set exposure temperature will be described with reference to the flowchart of FIG.

[0042] Once in the high temperature exposure mode, first, the temperature T _C of the test chamber 3, waits for reaching the set exposure temperature T _H (step S1). Then, at T _C = T _H, then
Last, the temperature difference [Delta] T ₂ of the temperature T _C of the detected temperature T _HS and test chamber 3 hot bath temperature sensor 21 at the time of current sampling, delta
The T ₁ is reset to 0 (step S2).

[0043] Then, the temperature sensor of the high temperature chamber temperature sensor 21 and the test chamber 3, the temperature T _HS, detects T _C (step S3), and calculates the temperature difference [Delta] T ₁ (step S
4).

Next, the temperature difference ΔT ₂ at the previous sampling
Is obtained from | (ΔT ₂ −ΔT ₁ ) / Δt | = A (step S5), and the time change rate A is compared with a predetermined small value ε (step S6). A ≦
If it is not ε, it is determined whether or not it is within the high-temperature exposure set time set by the user with the input means 31 (step S7).

If it is not within the set time, the high temperature exposure mode is ended. If it is within the set time, the temperature difference data is moved to the previous data (step S8), and after waiting for the sampling time Δt (step S9). , Step S
3 and the above operation is repeated. And step S
If NO in 7, the process ends.

On the other hand, if A ≦ ε in step S6, after waiting for a predetermined period of time to stabilize (step S10), it is determined whether or not the temperature of the low-temperature bath 2 is equal to or lower than the pre-cooling set temperature (step S11). If the temperature is below the pre-cooling temperature,
On the other hand, if the temperature is not equal to or less than the pre-cooling set temperature, as long as the temperature is within the high-temperature exposure set time set by the user with the input means 31, it waits until the low-temperature bath 2 becomes equal to or lower than the pre-cool set temperature. The process ends (step S12).

Upon completion, the low-temperature exposure mode is immediately entered, and the low-temperature exposure mode is controlled in the same manner as described above. Thereafter, the high-temperature and low-temperature exposure modes are repeated for the set cycle.

As described above, since the specimen 5 is determined to be stable near the set exposure temperature by the high temperature tank temperature sensor 21 or the low temperature tank temperature sensor 22, the temperature sensor is directly connected to the specimen 5. No need to install.

When it is determined that the specimen 5 has reached the set exposure temperature, the process shifts to the next exposure mode. Therefore, only the temperature change stress is applied to the specimen 5, and FIG. As shown, the test time can be reduced.

As shown in FIG. 4 (a), the high temperature bath temperature _THS once decreases from the preheating temperature and then increases again. _{Therefore, ΔT (= T C -T HS} ) , after once increased from [Delta] T = 0, stably decreased again. The same applies to the case of FIG. Therefore, the determination is made not based on the value of ΔT but on the time change rate.

In the low-temperature exposure mode, it is possible to determine in the same procedure that the specimen 5 has reached the set exposure temperature.

[0052]

As described above, according to the present invention, when the time rate of change of the temperature difference between the outlet temperature of the test chamber and the test chamber temperature becomes equal to or less than a predetermined value, the specimen reaches the preset temperature. Since it is determined that the temperature has reached the set temperature of the test sample, it can be detected with a simple configuration.

The temperature of the outlet of the test tank and the temperature in the test tank are detected, and the time change rate of the temperature difference between the temperature of the test tank outlet and the temperature of the test tank is calculated. In this case, the test mode is switched, so that the test time for environmental tests such as a thermal shock test can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control configuration of a thermal shock device as an example of an environmental test device to which the present invention is applied.

FIG. 2 is a schematic configuration diagram of a thermal shock device as an example of an environmental test device to which the present invention is applied.

FIG. 3 is a schematic configuration diagram of a thermal shock device showing a state of each of dampers 16a to 16f and a circulation direction of air in the device.
(A) shows a high-temperature exposure mode state, and (b) shows a low-temperature exposure mode state.

4A and 4B are diagrams showing transition of a temperature change. FIG. 4A shows a high-temperature exposure mode state, and FIG. 4B shows a low-temperature exposure mode state.

FIG. 5 is a flowchart illustrating a procedure for determining that the temperature of a test sample has reached a set exposure temperature, which is an example of a high-temperature exposure mode.

FIG. 6 is a diagram showing a temperature transition in a thermal shock test by a thermal shock device to which the present invention is applied.

FIG. 7 is a diagram showing a temperature transition in a conventional thermal shock test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-temperature tank 2 Low-temperature tank 3 Test tank 5 Specimen 6a High-temperature tank partition 6b High-temperature inlet 6c High-temperature outlet 6d Low-temperature inlet 6e Low-temperature outlet 6f External air outlet 6g External-air inlet 11 High-temperature tank heater 12a-12c Fan DESCRIPTION OF SYMBOLS 13 Refrigerator 14 Low temperature tank heater 16a-16f Damper 21 High temperature tank temperature sensor (outlet temperature detection means) 22 Low temperature tank temperature sensor (outlet temperature detection means) 23 Test tank windward temperature sensor (test tank temperature detection means) 24 Test tank Downwind temperature sensor (test tank temperature detection means) 31 input means 32 control unit 33 sequence controller 321, 322 selection means 323 temperature difference calculation means 324 storage means 325 change rate calculation means 326 determination means

────────────────────────────────────────────────── ─── Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 3/60 G01N 17/00 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. A test tank capable of accommodating a specimen, having a fluid inlet / outlet sandwiching the specimen, and a fluid having a predetermined temperature from the inlet for changing the specimen to a preset temperature. And a fluid supply means for causing the fluid to flow out from the outlet, a test vessel temperature detecting means provided in the test vessel, and an environmental test device comprising an outlet temperature detecting means provided at the outlet. The time rate of change of the temperature difference between the two temperatures detected by each temperature detecting means is obtained, and the time rate of change is compared with a predetermined value. A method for determining a specimen temperature attainment, wherein it is determined that the temperature has reached the preset temperature. 2. An environmental test apparatus capable of accommodating a sample, having a test chamber having a fluid inlet / outlet sandwiching the sample, and performing an environmental test in a plurality of exposure modes. A test tank temperature detecting means provided, an outlet temperature detecting means provided at the outlet, a temperature difference calculating means for obtaining a temperature difference between both temperatures detected by the respective temperature detecting means, and a calculated temperature difference Rate-of-change calculating means for calculating the rate of change of time, determining means for determining whether the calculated rate of time change is equal to or less than a predetermined value, and switching means for switching the exposure mode when the time rate of change is equal to or less than the predetermined value. An exposure mode switching control device, comprising: