New reflector materials in SMD-LED package application

In recent years, LED devices have been developed and widely used in display, display backlight module and general lightings. In this study, three unsaturated polyester (UP) polymers were used as LED reflector materials. PLCC-3030 with low power single blue led was designed as a test vehicle to evaluate two new UP type reflectors (UP-A1, UP-A2) and three commercial reflector materials (UP-B, EP, PCT). Commercial transparent encapsulants were used in this package. Red ink soak test for PLCC-3030 package after encapsulation of five reflector materials to check the adhesion between reflectors and lead frames have been evaluated. Optical and electrical performance has been checked after encapsulation, MSL test and reliability test. There is no obvious crack of encapsulant was observed or catastrophic failure was occurred after MSL level 3. The lumen decay of LEDs with UP materials is around 5% after MSL level 3 test. New reflector materials of UP-A1, UP-A2 and commercial materials of UP-B, EP and PCT could be passed the red ink test after MSL level 3 tests. The lumen decay of LEDs with UPs and the other commercial reflector materials is between 4%~7% after 110°C/ 1000 hrs test, and between 10%~18% after 85°C/85% R.H./ 1000 hrs test. The lumen decay of LEDs is only about 1~3% after TCT test. The lumen decay of LEDs with UPs and the other commercial reflector materials is between 9%~13% after HAST for 264 hrs test. The new reflector materials, UP-A1 and UP-A2, show good package performance and show good optical and electrical performance after encapsulation and reliability test.