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Compared with the in-plane switching (IPS) mode of the liquid crystal display (LCD), the vertical-alignment (VA) LCD mode provides an excellent contrast ratio and a fast response time, but it still has a relative weakness: image quality deterioration as a function of the viewing direction. In the VA mode, the pixel division method, in which two different gamma curves from the divided pixels are integrated, is generally used to improve the off-axis image quality. Reported herein is the new VA mode for enhancing the off-axis image without decreasing the transmittance. The pixels divided into 12 domains instead of 8 using double electrode layers produce three different gamma curves from the high, middle, and low pixels, which are combined and enhance the image quality. In this pixel structure, the middle pixels are formed by two electrode layers and produce the third gamma curve. The new design of the VA mode shows the best off-axis image quality in the VA mode, which is the most comparable with that in the IPS mode, even with the organic light-emitting diode, and will provide a solution for the heavy competition in the ultrahigh-definition (UHD) and large-LCD-TV-panel market in the very near future. [ABSTRACT FROM AUTHOR]

Using a photo-luminescent cholesteric liquid crystal (PL-CLC) cell, tri-stable electro-optic switching behaviour was demonstrated. Stable planar, uniformly lying helix (ULH), and focal conic states were obtained at an electric field of zero after applying proper electric signals corresponding to each state. When a PL-CLC cell was placed on a ultraviolet (UV) back-light, the cell emitted fluorescent light with different types of polarization corresponding to the liquid crystal (LC) state: the planar, ULH, and focal conic states emitted circularly polarized light, linearly polarized light, and un-polarized light, respectively. Hence, the proposed PL-CLC cell worked as a tri-stable polarization-switching light source. We also demonstrated that the PL-CLC cell can be used to fabricate a bistable fluorescent LC device. [ABSTRACT FROM AUTHOR]

We propose a method for vertical alignment (VA) of liquid crystals (LCs) without alignment layers by mixing only a very low concentration (0.05 wt%) of an organic compound with LCs. The electro-optic characteristics of a VA cell fabricated by the proposed method were almost the same as those of a conventional VA cell with VA layers. Moreover, we used the proposed method to realise a polymer-stabilised VA device with a rapid response time without alignment layers. The proposed method can simplify the fabrication process and reduce the manufacturing cost of LC display devices by removing the need for alignment layers and the alignment process such as coating of polyimide layers and the UV exposure for the photo-alignment. We believe that the proposed method can play an essential role in the fabrication of plastic flexible LC display devices requiring the low-temperature process. [ABSTRACT FROM AUTHOR]

A transflective liquid crystal display using polymer-stabilised vertical alignment mode with fishbone-shaped electrode structure is proposed. Using the polymer stabilisation technique and patterned direction of pixel electrode structure, initial surface tilt angle and azimuthal angle can be well defined such that the liquid crystal is almost vertically aligned in the transmissive part while it has a certain pretilt angle that satisfies effective retardation of λ/4 with azimuthal direction of 45o with respect to the analyser in the reflective part. With optimisation of cell structures and surface tilt angles in the transmissive and reflective parts, a high performance transflective display showing excellent readability in any environment light conditions and single-gamma characteristic without using any retardation film or in-cell retarder can be achieved. [ABSTRACT FROM AUTHOR]

We have studied the lasing characteristics of a dye-doped nematic layer sandwiched by two polymeric cholesteric liquid crystal (CLC) films as photonic band gap (PBG) materials. The nematic layer acts as a defect layer, the anisotropy of which brings about the following remarkable optical characteristics: (1) reflectance in the PBG region exceeds 50% due to the retardation effect, being unpredictable from a single CLC film; (2) efficient lasing occurs either at the defect mode wavelength or at the photonic band edge; and (3) the lasing emission due to both the defect mode and the photonic band edge mode contains both right- and left-circular polarizations, while the lasing emission from a dye-doped single CLC layer with a left-handed helix is left-circularly polarized. [Copyright &y& Elsevier]