Enhancement of viewing angle properties of a single-domain fringe-field switching mode using zero pretilt alignment. (17th September 2015)

• Record Type: Journal Article
• Authors: Oh, Seong-Woo; Lee, Dong-Jin; Park, Min-Kyu; Park, Kyoung Ho; Lee, Joun-Ho; Kim, Byeong Koo; Kim, Hak-Rin
• Is Part Of: Journal of physics. Volume 48:Number 40(2015)
• Publication Date: 2015-09-17
• Subjects: liquid crystal -- fringe-field switching -- viewing angle -- pretilt angle -- polymer stabilization; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/48/40/405502
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: We demonstrated the effect of the pretilt angle on the viewing angle properties of the single-domain fringe-field switching (FFS) mode, and proposed a method to enhance the viewing angle properties. Firstly, we investigated the origin of the asymmetric viewing angle problems in the field-on and off states by performing a field-induced liquid crystal (LC) reorientation analysis. Because of the asymmetric properties induced by the coupling between the tilting angle of the LC director and the polar component of the electric field, a zero pretilt angle is essential for the symmetric viewing angle properties. Secondly, to eliminate the pretilt angle, which is generally inevitable with the rubbing process, we applied polystyrene (PS) alignment layer which generates an easy axis perpendicular to the rubbing direction. Azimuthal anchoring energy and thermal stability of the PS layer were improved by employing UV-curable reactive mesogen (RM) within the LC cell. The RM-stabilized PS layer preserved the zero pretilt angle with enhanced thermal stability. Finally, by evaluating 2.4 in QVGA single-domain FFS LC cells, we confirmed the improved alignment ability of the RM-stabilized PS layer and the effect of the zero pretilt angle on electro-optical properties such as response time and viewing angle.