Title :
Reverse-Mode Polymer-Stabilized Dual-Frequency Cholesteric Texture Cell for Dual Mode Operations
Author :
Che-Hsyan Wang ; Cheng-Che Wu ; Ya-Ting Yang ; Tien-Lung Chiu ; Jiunn-Yih Lee ; Jiun-Haw Lee
Author_Institution :
Dept. of Mater. Sci. & Eng., Nat. Taiwan Univ. Sci. & Technol., Taipei, Taiwan
Abstract :
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.
Keywords :
cholesteric liquid crystals; optical polymers; optical switches; alternating current bias; cholesteric liquid crystal; dual dielectric anisotropies; dynamic switch; focal-conic texture; frequency 35 kHz; frequency 60 Hz; planar texture; polymer concentration; polymeric mixture; reverse-mode polymer-stabilized dual-frequency cholesteric texture cell; Anisotropic magnetoresistance; Dielectrics; Force; Optical switches; Polymers; Time factors; Bistable operation; dynamic switch; polymer network distortion; polymer-stabilized dual-frequency cholesteric texture (PSDFCT);
Journal_Title :
Display Technology, Journal of
DOI :
10.1109/JDT.2012.2215838