Recent advances on polymer‐stabilized blue phase liquid crystal materials and devices

Abstract

Polymer-stabilized blue phase liquid crystals (PS-BPLC) have become an increasingly important technology trend for information display and photonics applications. BPLCs exhibit several attractive features, such as reasonably wide temperature range, submillisecond gray-to-gray response time, no need for alignment layer, optically isotropic voltage-off state, and large cell gap tolerance. However, some bottlenecks such as high operation voltage, hysteresis, residual birefringence, charging issues due to the large capacitance, and relatively low transmittance remain to be overcome before their widespread applications can be realized. Recent progress on BPLC materials and devices has shown great promise. To realize the electro-optic effect of PS-BPLC, two driving modes: inplane switching and vertical field switching mode, have been developed. The material system of PS-BPLC, including nematic LC host, chiral dopant, and polymer network, are discussed. Each component plays an essential role affecting the stability and electro-optic properties of PS-BPLC.

Anisotropy of the electro-optic Kerr effect in polymer-stabilized blue phases

“…Mainly two approaches are being made in an effort to improve the Kerr coefficient: to improve the material characteristics, and to optimize the blue phase structure. The first approach is mostly chemistry oriented, such as developing liquid crystal molecules with large dielectric anisotropies [7][8][9][10][11][12]. The second approach involves adjusting the lattice parameter * yoshida@eei.eng.osaka-u.ac.jp or changing the structure of blue phases for improved performance [13,14].…”

Phase transitions and separations in a distorted liquid crystalline mixture

“…However, the presence of the guest component reduces the effective value of α as seen in Eq. (14). In order to preserve the validity of the approximation at higher guest component concentrations, σ has therefore been prevented from taking values between 0 and a value σ min .…”

“…12 In particular, polymer stabilization has been used to extend the temperature range over which the liquid crystalline blue phase occurs, with the goal of making its use for optical applications more practical. 13,14 The latter phase is defined by a complex structure involving a network of nematic line defects, and it is thought that the stabilization occurs as this structure drives the polymer, or more generally some other guest component, to separate into the high energy regions around the defects. 13,15 The kinetics of phase separation processes in a liquid crystal have been investigated previously using Landau theory, taking account of the coupling of the nematic order parameter in a mixture with the local concentration.…”

P‐108: WITHDRAWN: P‐109: Distinguished Student Poster: Diluter Effects on Large Dielectric Anisotropy Blue Phase Liquid Crystals

“…Polymer-stabilized blue phase liquid crystal (PS-BPLC) [1,2] is a promising candidate for next-generation transmissive and reflective display [3][4][5][6] and photonic devices [7] because of its attractive features, such as submillisecond response time [8,9], no need for surface alignment layer, and optically isotropic dark state. However, high operation voltage still hinders its widespread applications.…”