Active packing method for blue light-emitting diodes with photosensitive polymerization: formation of self-focusing encapsulates.
A novel light-emitting diode (LED) packaging method, named the active packaging (AP) method, is presented in this paper. In this method, during the LED packaging process, the light emitted from a GaN LED chip itself is employed to package the LED encapsulant, thereby eliminating the need to utilize a mold. Current injection into a bare LED chip, triggers a photosensitive epoxy to polymerize, leading to the formation of mushroom lamp cap on the LED chip. The emission properties of LEDs fabricated by this method, including their emission beam profiles and light outputs, were characterized. The results showed that a self-focusing effect happened with the addition of an epoxy on the chip. The simulation demonstrated that the geometry the encapsulant controlled the beam pattern of emission. Further, the self-focusing effect was believed to be caused by the combination of the threshold energy of epoxy polymerization, the beam pattern and the power output of the LED chip.
School for Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510631, China. wanghao@scnu.edu.cn
Hao
H
Wang
Jae-Hyoung
JH
Ryu
Kyu-Seung
KS
Lee
Chun Hua
CH
Tan
Lihua
L
Jin
Songmei
S
Li
Chang-Hee
CH
Hong
Yong-Hoon
YH
Cho
Songhao
S
Liu
D003116:Color; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007909:Lenses; D008029:Lighting / Q000295:instrumentation*; D010777:Photochemistry / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D012666:Semiconductors
D011108:Polymers