Journal of the Korean Ceramic Society (한국세라믹학회지)

The Korean Ceramic Society (한국세라믹학회)
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Effect of Heat Treatment Temperature and Coating Thickness on Conversion Lens for White LED

백색 LED용 색변환 렌즈의 열처리 온도 및 코팅 두께에 따른 영향

  • Lee, Hyo-Sung (Optic & Display Material Team, Korea Institute of Ceramic Engineering and Technology) ;
  • Hwang, Jong Hee (Optic & Display Material Team, Korea Institute of Ceramic Engineering and Technology) ;
  • Lim, Tae-Young (Optic & Display Material Team, Korea Institute of Ceramic Engineering and Technology) ;
  • Kim, Jin-Ho (Optic & Display Material Team, Korea Institute of Ceramic Engineering and Technology) ;
  • Jung, Hyun-Suk (Department of Materials science and Engineering, Sungkyunkwan University) ;
  • Lee, Mi Jai (Optic & Display Material Team, Korea Institute of Ceramic Engineering and Technology)
  • 이효성 (한국세라믹기술원 광디스플레이소재팀) ;
  • 황종희 (한국세라믹기술원 광디스플레이소재팀) ;
  • 임태영 (한국세라믹기술원 광디스플레이소재팀) ;
  • 김진호 (한국세라믹기술원 광디스플레이소재팀) ;
  • 정현석 (성균관대학교 신소재공학과) ;
  • 이미재 (한국세라믹기술원 광디스플레이소재팀)
  • Received : 2014.09.22
  • Accepted : 2014.11.14
  • Published : 2014.11.30
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Abstract

Today, silicon and epoxy resin are used as materials of conversion lenses for white LEDs on the basis of their good bonding and transparency in LED packages. But these materials give rise to long-term performance problems such as reaction with water, yellowing transition, and shrinkage by heat. These problems are major factors underlying performance deterioration of LEDs. In this study, in order to address these problems, we fabricated a conversion lenses using glass, which has good chemical durability and is stable to heat. The fabricated conversion lenses were applied to a remote phosphor type. In this experiment, the conversion lens for white LED was coated on a glass substrate by a screen printing method using paste. The thickness of the coated conversion lens was controlled during 2 or 3 iterations of coating. The conversion lens fabricated under high heat treatment temperature and with a thin coating showed higher luminance efficiency and CCT closer to white light than fabricated lenses under low heat treatment temperature or a thick coating. The conversion lens with $32{\mu}m$ coating thickness showed the best optical properties: the measured values of the CCT, CRI, and luminance efficiency were 4468 K, 68, and 142.22 lm/w in 20 wt% glass frit, 80 wt% phosphor with sintering at $800^{\circ}C$.

Keywords

References

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