Light Emitting Diodes
Active packing method for blue light-emitting diodes with photosensitive polymerization: formation of self-focusing encapsulates Hao Wang 1, 2 *, Jae-Hyoung Ryu3, KyuSeung Lee2, Chun Hua Tan1, Lihua Jin2, Songmei Li2, Chang-Hee Hong3, YongHoon Cho2, Songhao Liu1 School for Information and Optoelectronic Science and
Engineering, South China Normal University. Guangzhou 510631, China
2 Nano-Bio- Photonics Laboratory, Department of Physic s
6 and Institute for Basic Science Research, Chungbuk National University, Cheongju
361-763, Korea
1 Opto Electronics Laboratory, Department of Semiconductor Science and Technology,
Chonbuk National University, Jeonju, 561-756, Korea
2 wanghao@scnu.edu.cn 1 3 Abstract: 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.
C2008 Optical Societ y of America OCIS codes: (250.0250 ) Optoelectr onics;
(220.4610) Optical fabrica tion. References and links
5 1. D.A. Steigerwa ld, J.C. Bhat, D. Collins, R.M. Fletcher, M. O. Holcomb, M. J.
Ludowise, P. S. Martin, S. L. Rudaz, " Illumination with solid state lighting technology,"
IEEE
Engineering, South China Normal University. Guangzhou 510631, China
2 Nano-Bio- Photonics Laboratory, Department of Physic s
6 and Institute for Basic Science Research, Chungbuk National University, Cheongju
361-763, Korea
1 Opto Electronics Laboratory, Department of Semiconductor Science and Technology,
Chonbuk National University, Jeonju, 561-756, Korea
2 wanghao@scnu.edu.cn 1 3 Abstract: 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.
C2008 Optical Societ y of America OCIS codes: (250.0250 ) Optoelectr onics;
(220.4610) Optical fabrica tion. References and links
5 1. D.A. Steigerwa ld, J.C. Bhat, D. Collins, R.M. Fletcher, M. O. Holcomb, M. J.
Ludowise, P. S. Martin, S. L. Rudaz, " Illumination with solid state lighting technology,"
IEEE
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