Automatic measurement system for junction temperature of light emitting diodes

In this paper, we present a PC-based automatic measurement system for measuring the junction temperatures of light-emitting diodes (LEDs) operated at different forward currents. This system is described in three major parts: (1) screen panel and function design of control software (2) data acquisition and heating hardware (3) system integration and function test. In order to check and demonstrate its performance, the junction temperatures of three InGaN/GaN multiquantum well (MQW) LEDs have been performed by this system. The operating currents are reported in the range of 10-300 mA and the measured junction temperatures are obtained from 30 to 200°C.