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Effect of Curing Method on the Reliability of Silicone Encapsulant for Light Emitting Diode

LED용 실리콘 봉지재의 경화방법이 신뢰성에 미치는 영향

  • Kim, Wan-Ho (New Lighting Solution R&BD Sector, Korea Photonics Technology Institute) ;
  • Jang, Min-Suk (New Lighting Solution R&BD Sector, Korea Photonics Technology Institute) ;
  • Kang, Young-Rae (New Lighting Solution R&BD Sector, Korea Photonics Technology Institute) ;
  • Kim, Ki-Hyun (New Lighting Solution R&BD Sector, Korea Photonics Technology Institute) ;
  • Song, Sang-Bin (New Lighting Solution R&BD Sector, Korea Photonics Technology Institute) ;
  • Yeo, In-Seon (Department of Electrical Engineering, Chonnam National University) ;
  • Kim, Jae-Pil (New Lighting Solution R&BD Sector, Korea Photonics Technology Institute)
  • 김완호 (한국광기술원 신광원조명사업단) ;
  • 장민석 (한국광기술원 신광원조명사업단) ;
  • 강영래 (한국광기술원 신광원조명사업단) ;
  • 김기현 (한국광기술원 신광원조명사업단) ;
  • 송상빈 (한국광기술원 신광원조명사업단) ;
  • 여인선 (전남대학교 전기공학과) ;
  • 김재필 (한국광기술원 신광원조명사업단)
  • Received : 2012.07.30
  • Accepted : 2012.09.22
  • Published : 2012.10.01

Abstract

Encapsulant curing in terms of convection oven leads to thermal induced stress due to nonuniform thermal conductivity in LED package. We have adopted infrared (IR) light for silicone curing in order to release the stress. The light uniformity irradiated on an encapsulant surface is confirmed to be uniform by optical simulation. Shear strength of die paste using IR compared to convection oven is increased 19.2% at the same curing time, which indicates curing time can be shortened. The indentation depth difference between center and edge of silicone encapsulant in terms of convection oven and IR are 14.8% and 3.4%, respectively. Curing by IR also shows 2.3% better radiant flux persistency rate of LED at $85^{\circ}C$ after 1,000 h reliability test compared to convection curing.

Acknowledgement

Grant : 고효율 고신뢰성 LED 패키징 소재 기술 개발

Supported by : 지식경제부

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