DOI QR코드

DOI QR Code

Optical Properties of UV LEDs depending on Encapsulate Method using Silicone Encapsulants with Different Refractive Indices

굴절률이 다른 실리콘 봉지재의 봉지 방법에 따른 UV-A LED의 광 특성에 관한 연구

  • Received : 2014.12.10
  • Accepted : 2015.01.08
  • Published : 2015.03.31

Abstract

Optical characteristics including the radiant flux and viewing angle of UV LEDs were investigated according to both silicone encapsulants with different refractive indexes and lens shapes. Lead frame was fabricated using the enhanced heat dissipation characteristics with a heat slug structure and the reflector based on EMC(Epoxy Mold Compound) material. Four types of lens shapes were designed and their optical characteristics depending on the refractive index of silicone encapsulants were evaluated. The maximum radiant flux can be achieved when the height of lens are 1.32mm and 1.08mm for silicone encapsulants with low and high refractive indexes, respectively. Depending on the encapsulating method, the viewing angle changes from $148.9^{\circ}$ to $130.2^{\circ}$ for low refractive index and from $145.3^{\circ}$ to $136.8^{\circ}$ for high refractive index. As a result, it is found that the optical characteristics of UV LEDs can be controled through both encapsulating method and the refractive index of encapsulants.

Keywords

UV LED;Silicone;Refractive index;Radiant flux;Viewing Angle

References

  1. Z. Liu. S. Liu, Kai Wang, and X. Luo, "Status and prospects for phosphor-based white LED packaging," Front. Optoelectron. China, Vol. 2, No. 2, pp. 119-140, 2009. https://doi.org/10.1007/s12200-009-0011-2
  2. D. A. Steigerwald, J. C. Bhat, D. Collins, R. M. Fletcher, M. O. Holcomb, M. J. Ludowise, P. S. Martin, and S. L. Rudaz, "Illumination With Solid State Lighting Technology," IEEE J. Sel. Topics Quantum Electron., Vol. 8, No. 2, pp. 310-320, March/April 2002. https://doi.org/10.1109/2944.999186
  3. Jae-Bum Kim, Seong-Ran Jeon, Jae-Gwang Han, Sung-Ku Knag, Chang-Sub Chung, "Design and Evaluation of an Optical Curing System using UV Light-emitting Diodes" The Korean Physical Society, Vol. 60, No. 3, pp. 300-308, 2010, 3.
  4. Seong-Mo Ku, Jong-min lm, Chin-woo Yi, "Measurement of UV radiation of LED lighting", JIEIE, vol. 25, pp. 7-14, 2011.
  5. E. F. Schubert, Light Emitting Diode, 2nd ed. (Cambridge University Press, Cambridge) pp. 195. 2006.
  6. Heyong-Jin Kim.Jin-Yeol Yoo.Young-Rae Kang.Jae-Pil Kim.Joon-Seop Kwak, "A study of light output characteristics with various refractive indices and geometrical structures of the GaN based light-emitting device encapsulants", JIEIE, Vol. 26, No. 7, p.1-8, 2012, 6.

Acknowledgement

Grant : 유무기 복합소재를 이용한 UV 경화기용 고효율 SMD 구조의 UV A 패키지 및 광원 모듈 개발

Supported by : 산업통상자원부, 한국산업기술진흥원, 호남지역사업평가원