<p class="MsoNormal">This study describes the development of an evaluation method of uncertainty in temperature measurement of surface-mounted components by several types of thermocouples. Due to the miniaturization of electronic devices, temperature measurement techniques for miniaturized electrical components are strongly needed to ensure the operation's guaranteed temperature. Several types of thermocouples are widely used for measuring temperature. However, when the temperature measurement of the surface-mounted components is conducted by thermocouples, the components' temperature may decrease because the thermocouples dissipate heat like a pin fin. Therefore, to improve the miniaturized devices' temperature measurement accuracy by using thermocouples, an evaluation of heat transfer around thermocouples becomes essential.</p><p>In this study, the heat transfer around several thermocouples installed on the printed boards' surface was conducted while changing the thermocouples' operating conditions. As the test thermocouples, T-type and K-type thermocouples, which are widely used in the thermal management of electronic equipment, were evaluated. The diameter of the wire of the thermocouples was 0.1 mm and 0.2 mm. The effects of the surrounding temperature around test thermocouples on the heat leakage through the thermocouples were mainly evaluated. Our investigation found that the thermocouples' apparent net thermal resistance increased when the surrounding temperature was raised. When the surrounding air temperature in the heat dissipation completion distance, which is a distance between the installed point of thermocouples and a point that 90 % of heat through the thermocouples dissipates to the surrounding air, becomes higher, the temperature difference between the surface of the thermocouples and the surrounding air becomes smaller, and the apparent thermal resistance becomes high. We evaluated the relationship between the surrounding temperature and the apparent thermal resistance. From the results of the temperature difference and the results of FEM, the heat leakage to the thermocouples was evaluated, and the correction method of the actual temperature of the components was proposed.</p>

Fundamental Investigation of Effects of Surrounding Conditions on Measurement Uncertainty in Temperature of Surface-Mounted Components by Thermocouples

Paper Proceedings: https://asmedigitalcollection.asme.org/InterPACK/InterPACK2021/volume/85505

ASME 2021 International Electronic Packaging Technical Conference and Exhibition (InterPACK2021)

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