We propose an optical configuration of a twisted nematic liquid crystal device driven by a fringe field for a single-cell-gap transflective display. The dark state of the reflective part is realized by a nematic liquid crystal layer with a twist angle of 63.6° and retardation of 194 nm, while a quarter-wave plate is inserted for the dark state of the transmissive part. Wavelength dispersion of the liquid crystal layer is suppressed by introducing a half-wave plate. Different directions of electric fields rotate liquid crystals to 15° for the bright state of the reflective part, but to −30° for that of the transmissive part. With the proposed configuration, we can realize a high-brightness single-gamma transflective display in a single-cell-gap structure without any in-cell retardation layers.
Abstract This paper studies the relationship between the fault modes of hydraulic system and their flying parameters according to the principles of hydraulic systems. Based on the study of the working principle and composition architecture of the hydraulic system, the AMEsim software is used to construct a simulation model of the hydraulic system, to analyse the fault modes and mechanisms of key components in the system and their failure effects, and to establish a link between the fault modes and the flying parameters according to which practical evaluation parameters are provided for the subsequent monitoring and handling of system failures.
Abstract The pretilt angle of nematic liquid crystals on an alignment layer can be controlled from 2 to 89° by ion beam treatment of the alignment layer. Ion beam is used to partially destroy the vertical functional molecules of the vertical alignment materials. We also apply this method to no‐bend‐bias‐voltage optically compensated birefringence (OCB) mode with a pretilt angle of 55°. The OCB cell made by our method is a good candidate for high quality OCB mode because of the merits of uniformity of ion beam alignment and low power consumption of no‐bend‐bias voltage.
Abstract We propose a pixel electrode structure for the multi-domain vertical alignment liquid crystal mode with high optical efficiency. We form a micro-slit electrode structure on the top substrate to reduce the width of disclination lines at domain boundaries. We insert additional electrodes on the bottom substrate to improve the transmittance at the edges of each pixel. We confirm that using both structures, the transmittance can be increased from 22.9% to 27.3% with no change in the operating voltage.
We propose a method for in-plane switching of vertically aligned negative liquid crystals (LCs) for high transmittance and wide viewing angle. By applying an in-plane electric field using a double-layered electrode structure, LC molecules can be rotated by the vertical as well as the in-plane components of the applied field over the entire region so that high transmittance can be achieved. The threshold voltage difference can be obtained simply by varying the electrode structure, which can reduce the off-axis gamma shift in a multidomain vertical alignment LC cell.
We studied two types of bistable liquid crystal devices that can be operated in the memory mode as well as in the dynamic mode. One of them is a pixel-isolated twist-splay nematic LC cell that has two stable states of π- twist and splay. Polymer walls are formed at pixel boundaries by anisotropic phase separation between nematic liquid crystals and reactive mesogens. Operation in the memory mode can be achieved through bistable switching between the splay and π-twisted states. The other one is a bistable twisted-nematic mode that has two stable states of -π/2 and +π/2 twist. Three-terminal electrodes are used to apply both vertical and in-plane electric field to both devices. The proposed bistable modes has an infinite memory time and the fast transition time compared to other bistable liquid crystal modes.
We propose a bistable liquid crystal mode based on switching of the twist direction in a conventional π/2-twisted nematic cell. Switching between the −π/2 and +π/2 twist states can be performed by applying vertical and/or in-plane electric fields. The proposed bistable mode has an infinite memory time because the two stable twist states have the same elastic free energy.
We propose liquid-crystal (LC) devices capable of switching between reflective and transmissive modes using the scattering and transparent states of long-pitch cholesteric LCs (CLCs). Two different device configurations can be realized by changing the location of a CLC layer. Low-power operation without the parallax problem can be achieved using the bistable switching of CLCs. We believe that the proposed devices are potential candidates for highly efficient transflective displays.
Abstract We propose a new electrode structure using three voltage levels instead of two for high transmittance in the in‐plane switching liquid crystal mode. We confirmed that, by using the proposed structure, the transmittance of a LC cell can be increased from 29 % to 35 % at a slightly lower operating voltage. The transmittance of the proposed mode is higher than the conventional FFS mode.
Abstract In this work we propose a liquid crystal mode in which vertically‐aligned negative nematic liquid crystals are switched on by applying a fringe electric field. In the proposed mode, vertically‐aligned negative liquid crystals can be switched on by the vertical as well as in‐plane components of an applied fringe field so that high transmittance can be achieved. By fabricating a test cell, we experimentally obtained a transmittance of 33.7 %, which is 8.7 % higher than a homogeneously‐aligned fringe field switching cell using positive liquid crystals.
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