Title :
Photo-alignment techniques for liquid crystal alignment on treated orientation films
Author :
Seo, Dae-Shik ; Hwang, Lyul-Yeon
Author_Institution :
Dept. of Electr. Eng., Soong Sil Univ., Seoul, South Korea
Abstract :
We investigated the pretilt angle generation by linearly polarized ultraviolet (UV) irradiation for nematic liquid crystal (NLC) on rubbed polyimide (PI) surfaces. The pretilt angle of 4-n-penty-4-cyanobiphenyl (5CB) increased linearly with the duration of irradiation of UV light polarized parallel to the rubbing direction on rubbed PI surfaces with trifluoromethyl moieties. But, the pretilt angle of 5CB decreased linearly with the duration of UV irradiation polarized parallel to the rubbing direction on standard rubbed PI surfaces with side chains. We obtained infrared (IR) spectra demonstrating clear changes in the PI structure upon irradiation with linearly polarized UV light. Therefore, we conclude that the pretilt angle of NLC is changed by changes in the structure of polymer surface upon irradiation with linearly polarized UV light
Keywords :
abrasion; liquid crystal displays; nematic liquid crystals; polymer films; 4-n-penty-4-cyanobiphenyl; IR spectra; linearly polarized ultraviolet irradiation; liquid crystal alignment; nematic liquid crystal; photo-alignment techniques; pretilt angle generation; rubbed polyimide surfaces; rubbing direction; side chains; treated orientation films; Educational institutions; Flat panel displays; Infrared spectra; Liquid crystal displays; Liquid crystals; Optical polarization; Polyimides; Polymers; Rotation measurement; Surface treatment;
Conference_Titel :
Properties and Applications of Dielectric Materials, 1997., Proceedings of the 5th International Conference on
Conference_Location :
Seoul
Print_ISBN :
0-7803-2651-2
DOI :
10.1109/ICPADM.1997.616598
