Electrically switchable cholesteric gratings based on slit electrodes.

An electrically switchable diffraction grating (ESDG) based on cholesteric liquid crystal (CLC) filled into the cell with slit electrodes is demonstrated in this study. On one hand, with low voltage, the ESDG has high second order diffraction efficiency because of the alternating planar and fingerprint textures. With high voltage, on the other hand, the ESDG has high first order diffraction efficiency because of the alternating planar and homeotropic textures.

Polarization-independent and fast tunable microlens array based on blue phase liquid crystals.

This work investigates a polarization-independent and fast response microlens array. This array is composed of a concave polymer microlens array and blue phase liquid crystals (BPLCs). The microlens array can be either positive or negative, depending on the birefringence of the BPLCs.

Polarization-independent distortion corrector fabricated using polymer-dispersed liquid crystals.

We demonstrate a polarization-independent distortion corrector fabricated using a polymer-dispersed liquid crystal (PDLC) cell placed on the intermediate image plane of an optical system. At low voltage, a hazy PDLC cell scatters the incident rays and redirects the off-axis propagated chief ray. The chief ray approaches the principal point of the lens element, thereby decreasing image distortion.

Rotatable diffractive gratings based on hybrid-aligned cholesteric liquid crystals.

This work proposes a thermally rotatable grating that is based on hybrid-aligned cholesteric liquid crystals (HBA-cholesteric LCs). Experiments reveal that the HBA-cholesteric texture has a uniformly striped domain, which forms a grating, when the ratio of the cell gap to the helical pitch (d/p) is in the range of 2≤d/p≤3. The stripe direction of the HBA-cholesteric grating is predicted by the proposed vertically aligned LC layer model.

Influence of pretilt angle on disclination lines of liquid crystal lens.

This article investigates the effect of pretilt angle on disclination lines of liquid crystal (LC) lenses. When the pretilt angle of LCs is higher than 7°, the disclination lines are reduced and are moved to the boundary of the LC lens. The disclination lines at the boundary do not influence the focused beam profile of the LC lens.

Dual-view liquid crystal display fabricated by patterned electrodes.

We design a dual-view liquid crystal display (DVLCD) which display two different images in the left and right viewing directions simultaneously. The main-pixel of the DVLCD comprises the right sub-pixels (RSPs) and the left sub-pixels (LSPs). The LCs in the RSPs and the LSPs have the opposite rotation directions, which are controlled by the inclined electric fields provided by the patterned electrodes.

Polarization-independent and high-diffraction-efficiency Fresnel lenses based on blue phase liquid crystals.

A polarization-independent and high-diffraction-efficiency Fresnel lens is developed based on blue phase liquid crystals (BPLCs). The optically isotropic characteristic of BPLCs is used to produce a polarization-independent Fresnel lens. The small optical phase shift of BPLCs that is induced by the Kerr effect is sufficient for the BPLC Fresnel lens to have high theoretical and experimental diffraction efficiencies of 41% and ∼34%, respectively.

Extraordinarily wide-view and wide spectral bandwidth transflective liquid-crystal displays.

This work presents a simple compensation method for widening the viewing angle of transflective liquid-crystal displays (TR-LCDs). For an off-axis light, the slow axis of a biaxial film shifts linearly as the Nz factor is varied. By using this optical characteristic of a biaxial film, the broadband condition of broadband circular polarizers exactly holds over a full 80 degrees viewing cone, thus eliminating the off-axis light leakage to widen the viewing angle of TR-LCDs.

Optically compensated circular polarizers for liquid crystal displays.

An optical compensation principle of the crossed circular polarizers is developed to widen the viewing angle of high-transmittance multi-domain vertical-alignment liquid crystal displays (MVA-LCDs). The optical properties of a biaxial film are analyzed by the Berreman 4x4 matrix method, and the analytical solution for the slow-axis orientation of a biaxial film is calculated to obtain the compensation principle of the crossed circular polarizers. Based on this compensation principle, the high-transmittance MVA-LCD theoretically has a complete 80 degrees viewing cone for contrast ratio (CR)>100:1 and experimental results reveal that the compensated high-transmittance MVA-LCD can achieve a viewing angle of over the entire 80 degrees viewing cone for CR>20:1.

In-plane switching dual-frequency liquid crystal cell.

The electro-optical responses of the in-plane switching (IPS) dual-frequency liquid crystal (LC) cell operated with the amplitude-modulation method and the frequency-modulation method were investigated. The obtained results reveal that the electric torque exerted to the LCs and the strong anchoring energy produced from the rubbed polyimide dominate the reorientation of the LCs. With the frequency-modulation method, the generated electric torque combined with the strong surface anchoring energy give the cell a very short fall time, which is independent of the applied frequency.