Polymer(Korea) (폴리머)

The Polymer Society of Korea (한국고분자학회)
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Improvement of Optical and Thermo-mechanical Properties of Polycarbonate-based Diffusers for LED Backlight Unit by Incorporation of Porous Silica Particles

실리카 다공체에 의한 발광다이오드 백라이트 유닛용 폴리카보네이트계 확산판의 광학 및 열-기계적 물성의 향상 연구

  • Kim, Hyo Jin (Department of Advanced Materials Engineering, Kyonggi University) ;
  • Kim, Dong Won (Department of Advanced Materials Engineering, Kyonggi University) ;
  • Kim, Seong Woo (Department of Chemical Engineering, Kyonggi university)
  • 김효진 (경기대학교 신소재공학과) ;
  • 김동원 (경기대학교 신소재공학과) ;
  • 김성우 (경기대학교 화학공학과)
  • Received : 2012.06.19
  • Accepted : 2012.08.06
  • Published : 2012.11.25
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Abstract

The polycarbonate (PC)-based optical diffusers for direct-lit LED backlight unit were prepared by using extrusion compounding followed by compression molding process. The application of inorganic porous silica particles as a diffusing agent in addition to conventional poly(methyl methacrylate) (PMMA) beads was attempted, and the optical, thermal, and mechanical properties of the prepared diffusers were investigated. The morphological observations revealed that the diffusing agents could be uniformly dispersed in the PC matrix without agglomeration by high shear stress generated during extrusion process. The incorporation of the porous silica particles mixed with PMMA beads remarkably enhanced the luminance uniformity with respect to both location and view angle for the diffuser, while minimizing the reduction in the absolute luminance, as compared with the diffuser containing only PMMA beads. In addition, thermal and mechanical properties of the diffusers were shown to be improved upon addition of the porous silica particles.

본 연구에서는 압출 컴파운딩 공정 및 압축 성형 공정을 이용하여 직하형 LED backlight unit(BLU)용 PC계 확산판을 제조하였다. 광 확산제로 무기 실리카 다공체의 적용을 시도하였으며, 제조된 확산판의 광학 및 열적, 기계적 물성의 변화를 조사하였다. 모폴로지 관찰을 통하여 광 확산제가 압출 공정 중 발생된 높은 전단응력에 의하여 PC 매트릭스 상에서 응집 현상 없이 균일하게 분산되었음을 확인하였다. 실리카 다공체를 보조 확산제로 첨가한 경우 확산판의 위치 및 시야각에 따른 휘도 균일도가 순수 아크릴 비드만을 첨가한 경우에 비해 뚜렷하게 향상되었으며, 반면에 절대휘도의 감소 정도는 매우 낮은 것으로 나타났다. 또한 첨가된 실리카 다공체는 확산판의 열 및 기계적 성질의 개선에도 기여하였다.

Keywords

Acknowledgement

Supported by : 한국산업기술평가관리원

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