화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Polymer(Korea), Vol.31, No.2, 148-152, March, 2007
Export Citation
반사형 콜레스테릭 칼라필터의 시야각에 따른 광특성 향상에 관한 연구
Improvement of Optical Characteristics in Viewing Directions in a Reflective Cholesteric Liquid Crystal Color Filter
김태현, 임영진, 황성진, 이명훈, 장원근1, 이승희†
  • 전북대학교 신소재개발연구소
  • 1한국광기술원
Tae Hyun Kim, Young Jin Lim, Seong Jin Hwang, Myong-Hoon Lee, Won-gun Jang1, and Seung Hee Lee†
  • Research Center of Advanced Material Development, Chonbuk National University, Jeonju Jeonbuk 561-756, Korea
  • 1Korea Photonics Technology Institute, Wolchul-dong, Buk-gu, Gwangju 500-460, Korea
E-mail:
초록
콜레스테릭 액정모노머를 이용하여 액정표시장치용 선택반사 칼라필터 원형을 개발하였다. 콜레스테릭 액정은 특정한 기판처리 조건에서 나선(helical twist) 구조를 갖는 액정으로서 피치와 비슷한 크기의 입사 파장을 반사시키는 독특한 선택반사의 광특성을 갖는다. 실험결과 R, G, B의 파장영역을 반사시키는 반구형으로 패턴된 콜레스테릭 반사 필름을 개발하여 그 반사파장의 피크 값을 살펴본 바, 시야각 방향 변화에 따라 적색, 녹색필름은 단파장쪽으로 반사파장 피크가 이동하였으며 청색의 경우 별다른 변화가 없었다. 포토리소그래피를 이용하여 포토레지스트(Photo-resist)를 thermal reflow방식으로 마이크로미터 크기의 반구형의 주기적인 패턴을 얻을 수 있었으며 그 위에 형성된 적색, 녹색, 청색의 필름은 패턴이 없는 경우에 비하여 시야각에 따른 반사파장의 변화가 적음을 육안을 통하여, 그리고 Lab좌표를 통해서 각각 정량적으로 확인할 수 있었다.
The prototype of color filters for the liquid crystal displays (LCD) using cholesteric liquid crystal monomers was produced. Cholesteric liquid crystal is characterized by the unique optical features of selective reflection, which is due to the helical twisting structures of LCs comparable to the wavelength of the incident light under certain conditions of substrate treatment. In the results of the experiment, cholesteric films for red, green, and blue light reflections respectively were produced and the viewing angle dependence of these films were investigated. Reflective light of red and green films shifted to shorter wavelength regions as viewing angle becomes greater, but blue one shifted very little. Periodic micrometer-sized half-spherical photoresist formed by thermal reflow method after photo-lithography was patterned on glass substrates. The viewing angle dependence of reflective light colors of red, green, and blue films on the patterned substrates compared with those on no patterned substrates was investigated. We could confirm the dependences were much smaller on the patterned substrates by bare eyes and Lab-color coordination methods qualitatively.
Keywords:color filters;cholesteric liquid crystal;photo-lithography;half spherical pattern;color shift
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