Comparison of thermal characteristics of Light-emitting Diode chips and electrical heating source

Micro heat pipe (MHP) has been an ideal device for heat transfer. With its high thermal conductivity coefficient, high temperature uniformity, a lot of research groups have studied its performance. Some researches just connected it to a metal heating source to study how the MHP dissipated the heat; this procedure is simpler than connected to Light-emitting Diode (LED) chips. However, the thermal characteristics, the interface and the output energy of heating rod are different. Therefore, the heating characteristics of these two heating sources should be carefully studied. In this paper, electrical heating rod installed on copper block as the heat source was attached to a MHP; meanwhile, the same power LED chips were bonded to the same MHP as comparison. The experimental results showed that the time of the MHP to reach the steady working state was shorter as LED chips integrated on the silicon substrate, and the thermal conductivities of MHPs heated by metal heating source and LED were 1256.3 W/ (K·m) and 1276.5 W/ (K·m), respectively. It can be concluded that the MHP was easier to start up after LED chips integrated on the silicon substrate, and the metal heating source´s specific power loss must be considered.