Dynamic Optical Probing and Inverses Problem of Liquid Crystal Alignment Structures

• Main Authors: Jien-Hui Li, 李建輝
• Other Authors: Jung Y. Huang
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/57181281680069262491

碩士 === 國立交通大學 === 顯示科技研究所 === 97 === The liquid crystal (LC) director profile is an important property for a variety of LC applications. In this study, we combine simulation and experimental measurement of the optical responses of hybrid alignment liquid crystal cells to demonstrate the functionality of LC director profile retrieval. Our simulation invokes the Q-tensor formalism of liquid crystal director calculation and Berreman matrix method for the optical response of LC. An electron-multiplying charge coupled device and a delay time generator were combined to capture the dynamic optical image of the liquid crystal cells. We discovered that by including a hybrid alignment region into an OCB cell, the warm up time of the LC cell can be effectively eliminated. The relaxation time was unfortunately also increased. We also study the inverse problem of LC to retrieve the director profile of liquid crystal cell directly from the measured optical transmittance data. To retrieve the director profile from the inverse problem technique, we proposed a regularization matrix based on a priori knowledge of LC. We found our method can yield LC director profile reliably from the measured optical data covering a wide range of incident angle and 10% noise level. We further demonstrated the functionality by retrieving the liquid crystal director profiles of LC cells with applied voltage from the experimentally measured data.