Thermal resistance of light-emitting diodes

A detailed analysis of the heat flow in a light-emitting diode is carried out in the present paper. In the thermal model of a light-emitting diode, the heat flow from the active region throughout the area between it and the top contact, the nonuniform heat flux density distribution in the active region due to the current-spreading effect as well as the temperature dependence of the thermal conductivity of the semiconductor material, are taken into account. The solutions of the thermal conduction equation for a light-emitting diode are obtained for both the steady-state condition and the transient-state condition. The heat-spreading in the heat-sink is analyzed. The effect of LED construction parameters on its thermal resistance is illustrated in numerous figures.