Molecular Alignment of Ferroelectric Liquid Crystal in Wide-Gap Cell for Liquid Crystal Lens

Abstract

The high-speed response of ferroelectric liquid crystals (FLCs) is advantageous for optical devices such as an electrically controlled lens. We have investigated the molecular alignment structure of FLC in a wide-gap cell for application to the lens. As a result, it has been found that a zigzag defect-free FLC medium can be obtained by utilizing alignment films, which possess a smooth surface and give rise to the defect-free situation in a narrow-gap cell, and by cooling from the nematic to the smectic phase at a low rate of <1 C/min. However, the transformation of the smectic layer structure has been observed under an electric field, particularly under a very low electric field in the wide-gap cell. We have attempted to suppress this transformation, which considerably degrades the optical performance of FLC, by the polymer stabilization technique. #

Effect of Polymer Stabilization on Molecular Alignment of Ferroelectric Liquid Crystal in Wide-Gap Cell

“…For this realization, it is basically most important to obtain a defectfree FLC in a wide-gap cell. In our previous paper, 29) we reported the molecular alignment structure and the technique for obtaining a defect-free alignment of FLCs in a wide-gap cell as follows: a defect-free FLC medium can be obtained even in a wide-gap cell by utilizing alignment films with smooth surfaces and by cooling from the isotropic liquid to the ferroelectric smectic-C Ã (SmC Ã ) liquid crystal phase at a low rate of <1 C/min. Thus, the defect-free FLC was obtained under the quiescent condition even in a wide-gap cell.…”

“…As a result, the structural defects, which considerably degrade the optical performance, occur. 29) In this study, we try to suppress the layer transformation by utilizing the polymer stabilization technique [30][31][32][33][34][35][36][37][38][39][40][41][42] and research the effect of the polymer on the FLC molecular alignment structure.…”