Hybrid aligned cholesteric: A novel liquid-crystal alignment

Lewis, M. R.; Wiltshire, M. C. K.
October 1987
Applied Physics Letters;10/12/1987, Vol. 51 Issue 15, p1197
Academic Journal
A hybrid aligned cholesteric (HAC) liquid-crystal (LC) structure is reported. The LC director tilt varies from a small angle at one surface to almost 90° at the other, while incorporating a helical twist. Cells having one surface treated with rubbed polyvinyl alcohol and the other with the organosilane octadecyltriethoxysilane, adopt the HAC structure when filled with a long pitch chiral mixture. The presence of the HAC structure was confirmed by studies of the variation of the optical rotation, first with thickness in a wedge cell and second with temperature for a compensated cholesteric mixture. Use of the HAC structure in a wedge cell is characterized by an absence of the pitch breaks seen with conventional alignments.


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