Comparison of Vertically Aligned and In-Plane-Switching Liquid Crystal Operation Modes: Optical Performance and Topological Defects
Shih-Yu Chao1*, Sheng-Kai Yao1, Jing-Kai Chou1, Jieh-Wen Tsung1, Wei-Yuan Chen2, Ting-Mao Fung2, Tsung-Hsien Lin2
1Electrophysic, National Chiao-Tung University, Hsinchu, Taiwan
2Photonics, National Sun Yat-sen University, Kaohsiung, Taiwan
* Presenter:Shih-Yu Chao,
In the research, we analyze and compare the Vertically aligned (VA) and In-Plane-Switching (IPS) liquid crystal (LC) operational modes, which includes the LC director field and optical performance of VA and IPS test cells. We use patterned Indium Tin Oxide (ITO) transparent electrodes to control the LC director and topological defects. We use polarizing optical microscope (POM) with crossed analyzer and polarizer and a lambda-wave plate on the diagonal direction are applied to derive the LC director field by the birefringence colors. In addition, transmittance versus applied voltage (Tr.-V) was directly extracted from the POM image with the help from the analysis software, Image J, which is our special technique. The Tr.-V of the VA and IPS mode cells are directly compared. In case of the VA cell, the topological point defect renders concentric diffraction pattern; The IPS cell, which gives a ripple-like director field, turns into a phase grating. The result are reported in this research.

Keywords: Vertically Aligned Liquid Crystal Operation Modes, In-Plane-Switching Liquid Crystal Operation Modes, Liquid Crystal director field, Topological Defects