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Proceedings Paper

Broadening of light reflection in glassy cholesteric materials and switchable polymer-stabilized cholesteric liquid crystals
Author(s): Michel Mitov; Corinne Binet; Christian Bourgerette
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Paper Abstract

A planar oriented cholesteric liquid crystal (CLC) may selectively reflect light. The reflection wavelength is related to the helix pitch and the wavelength bandwidth depends on the birefringence which is typically less than 0.3. In the visible spectrum, the bandwidth is often limited to 100 nm which is not suitable for specific purposes such as white-on-black polarizer-free reflective displays. Here we present two novel designs of CLC materials exhibiting light reflections on several hundreds of nanometers in the visible spectrum. The first type of broadband reflector is a glass non-polymeric CLC with a pitch gradient which developed during a thermal annealing. The second kind of approach leads to a Polymer-Stabilized CLC which is switchable when an electric field is applied. Here the material has been UV-cured under out-of-equilibrium conditions, i.e., when the CLC helicoidal pitch was varying during a thermal process. The elaboration processes are investigated in relationship with the optical properties and the microstructure as observed by transmission electron microscopy.

Paper Details

Date Published: 11 December 2001
PDF: 10 pages
Proc. SPIE 4463, Liquid Crystals V, (11 December 2001); doi: 10.1117/12.449950
Show Author Affiliations
Michel Mitov, CEMES/CNRS (France)
Corinne Binet, CEMES/CNRS (France)
Christian Bourgerette, CEMES/CNRS (France)


Published in SPIE Proceedings Vol. 4463:
Liquid Crystals V
Iam-Choon Khoo, Editor(s)

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