We propose a long-pitch cholesteric liquid crystal (ChLC) device capable of operation in both the dynamic mode and the memory mode. Fast switching between the homeotropic state and the focal conic state allows the display of moving pictures at a low operating voltage. In addition, we can write text messages on the proposed ChLC device by applying an external pressure locally to switch it from the focal conic state to the planar state.

No abstract

We proposed a method to obtain uniformly dispersed liquid crystal (LC) droplets in the polymer matrix. Polymer spacers were formed on the bottom substrate and the LC–reactive monomer (RM) mixture was injected between the substrates in the isotropic phase. After cooling to the room temperature, the RM molecules which have higher chemical affinity to the polymer spacers were diffused to the polymer spacers. Simultaneously, the LC molecules were separated from the RM molecules and formed homogenously dispersed droplets with a uniform size. The phase retardation, mechanical tolerance, and response time of the cell suggested were examined.

부산대학교 전자전기공학부 우 609-735 부산광역시 금정구 장전동 산 30번지 2 호서대학교 디스플레이공학부 우 330-713 충남 아산시 (2010년 11월 22일 받음, 2011년 1월 28일 수정본 받음, 2011년 2월 17일 게재 확정)쌍안정 카이랄 스플레이 네마틱 액정표시소자는 스플레이 상태와 -π 꼬인 상태를 쌍안정 상태로 사용하는 메모리 액정표시소 자이다. 셀 갭/피치의 값이 0.25일 경우 완전한 쌍안정 상태를 갖지만, -π 꼬인 상태에서 스플레이 상태로 전이시키기 위하여 Bistable chiral splay nematic liquid crystal display (BCSN LCD) is a memory type liquid crystal display using splay and -π twist states as two stable states. When the cell thickness to pitch (d/p) ratio is 0.25, splay and -π twist states have permanent memory time. However, when the transition from -π twist state to splay state is caused by a fringe field, pixel regions show that the splay state is not perfect, but rather includes a contribution from the -π twist state. In this paper, we propose a reflective BCSN LCD using -π twist state in which the two stable states do not coexist. The fabricated reflective BCSN LC cell shows a high contrast ratio of over 30:1 and response times of 950 ms and 450 ms in vertical and fringe field switching, respectively. The proposed cell also shows wide viewing angle characteristics of 180° in left-and right directions.