Opto-Thermal Performances Investigation of High-Power WLEDs With Different Reflective Dams

Abstract

Reflective dam is a common structure in white light-emitting diodes (WLEDs) packaging due to its advantages of light regulation, heat conduction, and enhanced packaging efficiency. In this work, the opto-thermal performances of high-power WLEDs with different reflective dams were investigated. The dichromatic light is closest to the natural white light when the phosphor concentration was set at 7 wt% from 5 to 12 wt%. As the WLED modules with different dam materials (Cu, Al, and Al2O3 ceramic) were fabricated and compared, the results showed that the WLED with Al2O3 reflective dam presents higher luminous efficiency (LE) of 132.37 lm/W and lower correlated color temperature (CCT) of 5633 K at a driving current of 350 mA. Besides, the Al2O3 reflective dam has a high reflectance of 95.2% from 400 to 800 nm. In addition, in the test of thermal performance, the stable temperature of the WLED module packaged with the Cu reflective dam is 162 °C at the current of 2000 mA, which shows lower surface temperature and displays better heat dissipation performance than the Al dam and the Al2O3 ceramic dam.