We demonstrated a polymer-stabilized dual-frequency cholesteric texture (PSDFCT) cell that functions smoothly in both dynamic switch and steady bistable usage, dual mode operation. The PSDFCT cell is a reverse-mode texture device containing a cholesteric liquid crystal (ChLC) and polymeric mixture. As polymer concentration increases, the PSDFCT cell exhibits increasing operational voltage and diminishing contrast ratio, which results from the increasing polymer network anchoring force to firmly stabilize the ChLC texture. Switching from planar texture to focal-conic texture is triggered by applying a threshold alternating current (AC) bias at low frequency (60 Hz). The opposite change, from focal-conic to planar texture, is achieved by varying the AC bias frequency from low (60 Hz) to high (35 kHz). The dual dielectric anisotropies of ChLC allow efficient dynamic switching by varying the bias frequency. Under bistable operation, a larger AC bias voltage generates polymer network distortion, directly affecting the ChLC mixture. The reciprocal switch, between planar texture and focal-conic texture, is performed at the greater AC bias by varying bias frequency.
© 2012 IEEE
Che-Hsyan Wang, Cheng-Che Wu, Ya-Ting Yang, Tien-Lung Chiu, Jiunn-Yih Lee, and Jiun-Haw Lee, "Reverse-Mode Polymer-Stabilized Dual-Frequency Cholesteric Texture Cell for Dual Mode Operations," J. Display Technol. 8, 663-668 (2012)