Tai-Hsiang Huang

Blue-Phase Liquid Crystal Displays With Vertical Field Switching

A low-voltage, high-transmittance, hysteresis-free, and submillisecond-response polymer-stabilized blue-phase liquid crystal (BPLC) display with vertical field switching (VFS) and oblique incident light is demonstrated. In the VFS mode, the electric field is in longitudinal direction and is uniform. By using a thin cell gap and a large oblique incident angle, the operation voltage is significantly reduced which plays a key role to eliminate hysteresis and residual birefringence. The VFS mode is a strong contender for the emerging BPLC display and photonic devices.

Influence of Polymerization Temperature on Hysteresis and Residual Birefringence of Polymer Stabilized Blue Phase LCs

This paper investigates the voltage hysteresis effect and residual birefringence in the polymer-stabilized blue phase I and II, under various phase separation conditions. By irradiating samples with ultraviolet (UV) light and curing the samples at a reduced temperature, the polymer in the blue phase formed a compact network along the direction of the UV light irradiation. The dense polymer network pinned the cubic lattice structure of the blue phase enabling it to return to its original optical isotropic state. In this manner, hysteresis and residual birefringence were suppressed from 4.16% to 1.67% and 0.057% to 0.002%, respectively. Although the driving voltage remained high, the reduction in hysteresis and residual birefringence are precisely the advancements required for the accelerating development of blue-phase liquid crystal displays.

Identification of polymer stabilized blue-phase liquid crystal display by chromaticity diagram

We reported an identification method of blue phase liquid crystal (BPLC) display status by using Commission International de l’Eclairage (CIE) chromaticity diagram. The BPLC was injected into in-plane-switch (IPS) cell, polymer stabilized (PS) by ultraviolet cured process and analyzed by luminance colorimeter. The results of CIE chromaticity diagram showed a remarkable turning point when polymer stabilized blue phase liquid crystal II (PSBPLC-II) formed in the IPS cell. A mechanism of CIE chromaticity diagram identify PSBPLC display status was proposed, and we believe this finding will be useful to application and production of PSBPLC display.

17.3: Hysteresis and Residual Birefringence Free Polymer-stabilized Blue Phase Liquid Crystal

This paper investigates the voltage hysteresis effect and residual birefringence in the polymer-stabilized blue phase PSBP, under various phase separation conditions. By curing the samples at a reduced temperature and controlling the polymeric propagation, the polymer in the blue phase formed a compact network near the surface of the electrode. The dense polymer network pinned the cubic lattice structure of the blue phase enabling it to return to its original optical isotropic state. In this manner, hysteresis and residual birefringence were suppressed from 6.3 % to 0.7 % and 0.33 % to 0.01 %, respectively. Although the driving voltage remained high, the reduction in hysteresis and residual birefringence are precisely the advancements required for the accelerating development of blue-phase LCDs.