Maintenance of stable light emission in high power LEDs

• Published in: Microelectronics and reliability 2012-05, Vol.52 (5), p.912-915
• Main Authors: Chou, Hung-Yu, Chen, Cheng-Chien, Yang, Tsung-Hsun
• Format: Article
• Language: English
• Subjects: Driving conditions; Electric current; Electric power generation; Electrical junctions; Emission; Light emission; Maintenance; Robustness
• ISSN: 0026-2714; 1872-941X
• DOI: 10.1016/j.microrel.2012.02.002

As well known, the light emission characteristics of the high power light-emitting diodes (LEDs) are very sensitive to the various driving conditions, especially the injected electric current and the junction temperature in operation. In this work, the dependency of the emission light from high power LEDs upon the driving electric current and the junction temperature will be explored in details. One integrated measurement system is proposed for the study in simultaneously obtaining all the thermal–optic–electric characteristics of LEDs throughout the measuring. Based on the basic feedback control methodology, one simple maintaining procedure is applied for the stable light emission in high power LEDs. It shows the robustness of the maintaining procedure from the environment change with the least heat dissipation in the operation of the high power LEDs. The results imply that all the thermal, the optic, and the electric properties of the high power LEDs should be taken into consideration in the same time rather than separately when maintaining their operation.