JPS60247184A - Apparatus for preventing dew condensation - Google Patents

Abstract

PURPOSE:To prevent dew condensation, by a method wherein the temp. of the article to be tested at low temp., which is present in the tank of a temp. environment testing apparatus, is raised and, when it is discriminated that the temp. of said article to be tested reached the dew point temp. or more outside the tank, said article to be tested is taken out of the tank. CONSTITUTION:A control part 1 controls each functional part on the basis of the program received in a memory part 2 and a temp. and humidity data memory part 3 stores the data of a temp. and humidity chart. A tank external temp. measuring operation part 8, a tank external humidity measuring operation part 10 and a surface temp. measuring operation part 15 respectivety applying A/D conversion to the outputs of a temp. sensor 7, a humidity sensor 9 and a surface temp. sensor 13 and perform the correction of the converted outputs to store the same temporarily. In a dew point operation part 5, absolute humidity is calculated from relative humidity-absolute humidity data by using the newest tank external temp. measured values stored in the operation parts 8, 10 and a dew point is further calculated from absolute humidity-dew point data and both values are temporarily stored in the dew point operation part 5. A dew condensation judge part 6 compares newest surface temp. with tank external dew point temp. and outputs the compared data to an output part 4, when the surface temp. is higher than the dew point temp., to inform the same to a tester.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to a temperature environment test system, and more particularly to a dew condensation prevention device for preventing dew condensation when a test object at a low temperature is taken out of a temperature environment test apparatus tank. .

(b)'Technical Background and Prior Art Temperature environment testing of electronic devices, especially low temperature testing, is an important and essential part of quality assurance of electronic devices. In this low-temperature test (usually -10 degrees to room temperature), if the test object is taken out of the chamber of the temperature environment test equipment at a low temperature after the test, the ambient temperature will rise rapidly, resulting in condensation and dew droplets on the surface of the test object. may occur.

Condensation and dew droplets must not be generated on electronic equipment, as this can cause problems such as rusting of metal parts, moisture absorption, expansion and deformation of plastic materials, and deterioration of electrical insulation. It is.

Therefore, in the past, the control temperature of the temperature environment test equipment was set to 1, for example.
The temperature was gradually increased at a rate of 5 degrees/hour, and the test object was taken out after waiting for the temperature of the test object to reach a state of thermal equilibrium with the temperature outside the tank. In reality, there is a time delay in temperature rise depending on the test object, and in consideration of safety, the test material is removed after a longer delay than necessary, resulting in a lot of time loss. Therefore, there is a need for the development of a device that can quickly remove the test object from the tank without causing dew condensation.

(C) In view of the drawbacks that exceed the purpose of the invention 1. The purpose of the present invention is to increase the temperature of a low-temperature test object in a tank of a temperature environment test device, while the temperature of the test object exceeds the dew point temperature outside the tank. To provide a dew condensation prevention device that can determine whether condensation has occurred and take it out of the tank.

(d) Structure of the Invention Therefore, the present invention includes a first means for measuring the surface temperature of a test object in a temperature chamber, a second means for measuring the temperature and humidity outside the temperature chamber, and a second means for measuring the temperature and humidity outside the temperature chamber. a dew point temperature obtained by the calculating means from the surface temperature of the test object measured by the first measuring means and the temperature and humidity measured by the second measuring means; It is configured to determine whether the surface temperature of the test object in the tank is above the dew condensation/droplet generation limit temperature and to notify 9 of the comparison result.

That is, with the dew condensation prevention device of the present invention, the test object whose temperature is rising to the outside temperature of the tank can be quickly taken out of the tank without causing dew condensation.

The principle of the present invention will be explained using FIG.

FIG. 1 is a temperature and humidity diagram, which shows the relationship between temperature and absolute humidity using relative humidity as a parameter. The condensation region is on the left side of the 100% relative humidity curve as shown in the figure, assuming the absolute humidity is constant.

As the temperature decreases, the relative humidity increases and eventually condensation occurs. Using the temperature and humidity diagram of FIG. 1, the dew point temperature outside the tank can be estimated by measuring the temperature and relative humidity outside the tank.

That is, in FIG. 1, if the indoor temperature is tl and the relative humidity is Wl, then the absolute humidity is Q kg/kg.

Q Dew point temperature t2 from point A where a certain straight line intersects the dew condensation area
It is possible to put

The present invention is a device that measures the surface temperature T of a test object in an environmental test device, and when T>t2, determines that there is no condensation even if the test object is removed from the test device, and notifies the tester. .

(e) Embodiments of the Invention An embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 2 is a block diagram showing the configuration of the apparatus of this embodiment, and FIG. 3 is a flow chart showing the operation of the embodiment.

The functions of each component will be explained below with reference to FIG.

The control section 1 is like a microcomputer and controls each functional section using a program stored in a storage section 2.

The temperature and humidity data storage unit 3 is a storage unit that stores data of the temperature and humidity diagram shown in FIG. 1, and the temperature and humidity data is created and stored in such a way that the dew point can be easily adjusted when temperature and relative humidity are given. For example, if you create and store relative humidity-absolute humidity data with a constant temperature and absolute humidity-dew point data of a condensation curve, the absolute humidity will be smaller than the temperature and relative humidity.

The dew point corresponds to the absolute humidity. Accurately, these data need to cover the entire area on the right side of the condensation curve, but as will be explained later, in consideration of errors caused by the test object and temperature response, certain stages are set for the parameters, and the measured values are Simplify the data, such as by adopting the safe side. For the above data, a table is created in which the starting address is attached for each group and is indexed by each calculation unit.

The outside temperature measurement calculation unit 8 is connected to a temperature sensor 7 such as a thermocouple installed outside the tank, reads the output of the temperature sensor 7 at regular intervals, performs A/D conversion, and performs necessary corrections and converts the output. Temporarily store the value.

The outside tank humidity measurement calculation unit 10 is connected to the humidity sensor 9 installed outside the tank together with the temperature sensor 7, and reads the output of the humidity sensor 9 at the same time as the temperature measurement, performs A/D conversion, and performs necessary correction. and temporarily store the value.

The surface temperature measurement calculation unit 15 is connected to the surface temperature sensor 13 installed on the surface of the test object in the test apparatus 11, and reads the output of the two surface temperature sensors 13 at the same time as measuring the temperature and humidity outside the tank. D conversion/correction is performed and the value is temporarily stored.

The dew point temperature calculation unit 5 calculates the dew point by referring to the latest temperature and humidity data stored in the tank outside temperature measurement calculation unit 8 and the tank outside humidity measurement calculation unit 10.

The dew condensation determination section 6 compares the surface temperature of the test object stored in the surface temperature measurement calculation section 15 with the dew point temperature, and determines whether the surface temperature is equal to or higher than the fog point.

The output unit 4 is used to alert the tester to the lamp, etc. In addition, the heating/cooling device 12 is the temperature environment test device 11.
It is attached to the tank and controls the temperature inside the tank.

The functions of each of the above parts and the operation of this embodiment will be explained below with reference to FIG. The flow chart shown in FIG. 3 is repeatedly executed at regular intervals of several seconds to several minutes, and the control unit 1 manages each unit, such as starting up each functional unit and transferring data.

As mentioned above, the temperature and humidity data storage section 3 stores a temperature and humidity diagram in advance, and by referring to the temperature table, for example, the leading address of the data storing the relative humidity-absolute humidity data at the temperature can be determined. The absolute humidity is stored in the relative humidity category at this address, and the absolute humidity can be found by specifying the relative humidity.Then, the dew point temperature can be estimated from the absolute humidity by referring to the absolute humidity-dew point temperature data. Rukoto can.

A) Temperature measurement calculation section outside the tank 8. Outside tank humidity measurement calculation unit 102
The surface temperature measurement calculation section 15 reads the temperature and humidity outside the tank and the surface temperature of the test object upon activation of the control section 1, performs A/D conversion and correction, and temporarily stores them in each calculation section.

B) The dew point calculation unit 5 uses the latest temperature and humidity measurement values outside the tank stored in the measurement calculation unit to calculate the temperature and relative humidity by referring to the relative humidity-absolute humidity data from the temperature table as described above. Calculate the absolute humidity that corresponds to the humidity. Next, the dew point calculation unit 5 calculates the dew point from the absolute humidity-dew point data and temporarily stores the value.

This dew point is calculated and updated for measurements at regular intervals.

C) After the above measurements and calculations have been performed, the dew condensation determining section 6 compares the latest surface temperature with the outside dew point temperature, and when surface temperature>dew point temperature, outputs the result to the output section 4 and notifies the tester.

Note that there are various types of electronic devices to be tested, such as printed boards and units, and the thermal conductivity varies depending on the shape and material of the parts that make up these devices, so the surface temperature of each part of the device will not be the same. When carrying out this test, select parts with low thermal conductivity or parts that are most susceptible to damage from condensation, and measure their surface temperatures. Even if the surface temperature is measured at several locations, it is easy to use the lowest measured temperature.

As explained above, according to the present invention, the temperature of the test object in a low temperature state in the temperature chamber of the temperature environment test device is raised by operating the temperature chamber, and when the temperature reaches the dew point temperature outside the chamber, the tester At that point, the test object can be taken out of the tank without condensation.

In FIG. 2, the temperature/humidity data storage section 3 and the temporary storage section in each calculation section can be included in the storage section 2, and the dew point temperature calculation section 5. The dew condensation determination section 6 can be included in the control section 1.

(f) Effect of invention The effects of the present invention are as follows.

B. It is possible to prevent dew condensation and dew droplets on the test object due to the test object being taken out of the temperature chamber too early during low-temperature tests.

B. Time loss due to waiting too long for the temperature of the test object to equilibrate to room temperature can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a temperature and humidity diagram, FIG. 2 is a block diagram showing the configuration of the apparatus of the embodiment, and FIG. 3 is a flow chart showing the operation. 1... Control section 3... Temperature/humidity data storage section 4... Output section 5... Dew point temperature calculation section 6... Condensation determination section 7... Temperature sensor outside the tank 8... Temperature measurement calculation unit outside the tank 9 Temperature sensor outside the tank 10 Humidity measurement calculation unit outside the tank 11 Temperature environment test device 13 Surface temperature sensor 14 Test object 15...Surface temperature measurement calculation section

Claims (1)

[Claims] A dew condensation prevention device used in a temperature environment test system that performs a temperature environment test of electronic devices, which includes a first means for measuring the surface temperature of a test object in a temperature chamber, and a first means for measuring the temperature and humidity outside the temperature chamber. a second means for measuring; a calculating means for calculating the dew point temperature at the measured temperature and humidity; and a surface temperature of the test object measured by the first measuring means and the temperature and humidity measured by the second means. A dew condensation prevention device characterized by comprising: means for reporting a comparison result of the dew point temperature obtained by the calculation means from the dew point temperature obtained by the calculation means.