A polarizer-free flexible and reflective electro-optical switch using dye-doped liquid crystal gels

Abstract

A polarizer-free flexible and reflective electro-optical switch using dye-doped liquid crystal (LC) gels is demonstrated. The electro-optical performances of both scattering and absorption based dye-doped LC gels depend on curing temperatures due to domain sizes of polymer networks. Such flexible electro-optical switch is bendable and trim-able because of the vertical polymer networks and gel-like materials. The dye-doped LC gel shows good reflectance ~55%, good contrast ratio~450:1 and fast response~6.4 ms at curing temperature 10 degrees C. The bending curvature is 21 mm. The dye-doped LC gels open a new window for trim-able electronic papers, decorative displays, electrically switchable curtains, and electrically switchable sun control film for the automobiles, homes or commercial buildings.

Fast response wavelength tunable filter using Vertically-Aligned Polymer-Stabilized Liquid Crystals (VA-PSLC) with a curing voltage

“…//I 1 1 / / / [5], this pretilt angle was provided by rubbing alone. We attempted to reproduce their experimental results using rubbing method.…”

“…This strong scattering effect was proposed and developed for potential applications where high light efficiency was required since no polarizers were needed in these devices [4]. However, it has also recently been shown that [5], by adding a pretilt angle to this VA-PSLC mode, e.g. using rubbing method, it is possible to reduce the scattering significantly while fast response time and good contrast ratio can still be obtained.…”

Polarizer-Free Gradient Dye-Doped Liquid Crystal Gels

“…The materials we employed are negative liquid crystal (ZLI-4788, Merck), a diacrylate monomer with a dichroic dye S428 (Mitsui, Japan) at 90:5:5 wt% ratios. The sample preparation process is similar to the previous one [22]. The cell gap was 5 mm.…”

“…Based on the combination of scattering and absorption we have recently developed polarizer-free LCDs using dye-doped dual frequency liquid crystal gels [19,20] and flexible dye-doped LC gels [21,22] with high contrast and fast response.…”

A Polarizer-Free Electro-Optical Switch Using Dye-Doped Liquid Crystal Gels

“…However, the electro-optical performance of dye-doped PDLCs is limited due to the dye molecules entangled in the polymer matrix, the order parameter of the dichroic dye and the dichroic ratio (typically ~10:1) of the dye. To avoid the problem of solubility between dye and polymer matrix, we have developed a polarizer-free electro-optical switch using a dye-doped dual-frequency liquid crystal (DFLC) gel and dye-doped LC gels [6,7,8,9]. Without polarizers, the optical efficiency is high and the viewing angle is wide.…”