TY - JOUR
T1 - Polyimide photo-alignment layers for inclined homeotropic alignment of liquid crystal molecules
AU - Usami, Kiyoaki
AU - Sakamoto, Kenji
AU - Yokota, Junichiro
AU - Uehara, Yoichi
AU - Ushioda, Sukekatsu
N1 - Funding Information:
We would like to thank K. Miki and J. H. G. Owen of NIMS for helpful comments on the manuscript. This work was supported in part by a Grant-in-Aid for Scientific Research (B) from Japan Society for the Promotion of Science (No.18360012), by a Grant-in-Aid for Exploratory Research from the Ministry of Education, Culture, Sports, Science and Technology (#17656010), and by a grant from the Iketani Science and Technology Foundation (#0171118-A).
PY - 2008/3/3
Y1 - 2008/3/3
N2 - We have succeeded in realizing an inclined homeotropic alignment of liquid crystal (LC) molecules by using photo-aligned films of a polyimide containing azobenzene in the backbone structure. To induce such an LC alignment, a side chain structure was introduced into the backbone structure. The LC pretilt angle, measured from the surface normal, could be controlled up to 1.75° by varying the light exposure in oblique angle irradiation with unpolarized light. Its thermal stability was examined by annealing the LC cell at 100 °C. No change was observed in the pretilt angle even after annealing for 36 h, indicative of its excellent thermal stability. Since photo-alignment has patterning capability, the photo-aligned polyimide film is expected as a promising alignment film for multi-domain vertical alignment mode LC displays.
AB - We have succeeded in realizing an inclined homeotropic alignment of liquid crystal (LC) molecules by using photo-aligned films of a polyimide containing azobenzene in the backbone structure. To induce such an LC alignment, a side chain structure was introduced into the backbone structure. The LC pretilt angle, measured from the surface normal, could be controlled up to 1.75° by varying the light exposure in oblique angle irradiation with unpolarized light. Its thermal stability was examined by annealing the LC cell at 100 °C. No change was observed in the pretilt angle even after annealing for 36 h, indicative of its excellent thermal stability. Since photo-alignment has patterning capability, the photo-aligned polyimide film is expected as a promising alignment film for multi-domain vertical alignment mode LC displays.
KW - Inclined homeotropic alignment of liquid crystal molecules
KW - Photo-induced alignment method
KW - Polyimide containing azobenzene in the backbone structure
KW - Pretilt angle
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U2 - 10.1016/j.tsf.2007.04.082
DO - 10.1016/j.tsf.2007.04.082
M3 - Article
AN - SCOPUS:39449133683
SN - 0040-6090
VL - 516
SP - 2652
EP - 2655
JO - Thin Solid Films
JF - Thin Solid Films
IS - 9
ER -