Author:
Kuang-Yu Hsu, Yi-Jing Chu, Andhi Indira Kusuma, Krishn Patel, Rajveer G. V., and Ming-Hsien Hsiao
Abstract:
Characterization of thin vapor chambers is performed using laser heating and non-contact infra-red pyrometers for temperature measurement. This is found to be a fast and accurate measurement for mass production applications. The temperature measurement at the heater position on the evaporator side is very critical but it is seriously affected by the heat laser light. For accuracy considerations the measurement requires a pulsed heating mode to allow the measurement to be made while the laser is off. The heater operates in an on-off heating mode rather than a continuous heating mode. It is necessary to analyze the deviation from the continuous heating mode. Two methods, including matching the heat and matching the temperature, are proposed and experimentally measured. The temperature accuracy of the on-off laser heating is less than ±1°C. The measurement data also show the transient response of the vapor chamber to a heat surge is temperature stabilizing.
In this study the effective heat capacity is proposed and used for the assessment of temperature stabilization performance. The experimental data also show the effective thermal capacity of the vapor chamber is 2.5 times larger than that of the copper plate.
Keywords:
Thin vapor chamber, vapor chamber characterization, vapor chamber transient analysis
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