The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Y Hirai - One of the best experts on this subject based on the ideXlab platform.
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a two dimensional Liquid Crystal simulation for thin film transistor Liquid Crystal displays
Liquid Crystals, 1993Co-Authors: Ken Sumiyoshi, K Takatori, N Takahashi, Y HiraiAbstract:Abstract A two-dimensional Liquid Crystal simulation, whose electrode configuration corresponds to that in a thin film transistor Liquid Crystal display (TFT-LCD), was carried out. Simulation results show that the lateral field between buslines and pixel electrode forms a reverse tilt domain. This reverse tilt domain leads to the disclination on the pixel electrode. The distance from the pixel electrode edge to this disclination location depends on the dielectric anisotropy and elastic constant for the Liquid Crystal. A small dielectric anisotropy or large elastic constant makes this distance small.
G Chidichimo - One of the best experts on this subject based on the ideXlab platform.
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reverse mode operation polymer dispersed Liquid Crystal with a positive dielectric anisotropy Liquid Crystal
Journal of Polymer Science Part B, 2011Co-Authors: Daniela Cupelli, Fiore Pasquale Nicoletta, Patrizia Formoso, Giovanni De Filpo, G ChidichimoAbstract:The development of electrically activated chromogenic materials is important for their potential applications in smart windows. Several previous works have reported on reverse mode operation polymer dispersed Liquid Crystals (PDLCs) based on negative dielectric anisotropy Liquid Crystals. They have a transparent OFF state, which turns opaque after the application of a suitable external electric field. Nevertheless, these devices have some limitations such as the use of large amount of expensive Liquid Crystals with peculiar physical-chemical properties. In addition, a good matching between the refractive index of Liquid Crystal and the polymer matrix one is required. The main result of this work is the achievement of reverse mode operation devices prepared with a positive dielectric anisotropy Liquid Crystal and characterized by a high OFF state transmittance obtained by the onset of high intensity built-in DC electric fields in a direct mode operation PDLC, which allows the OFF state homeotropic alignment of Liquid Crystal directors. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
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monomer Liquid Crystal emulsions for switchable films
Journal of Applied Physics, 1998Co-Authors: Giovanni De Filpo, Fiore Pasquale Nicoletta, J Lanzo, G ChidichimoAbstract:We have followed the phase separation process in mixtures of an organic monomer and nematic Liquid Crystals at different cooling rates. Systems form Liquid Crystal droplets in a Liquid Crystal-saturated monomer matrix and in some cases emulsions are stable over several months. Homogeneous droplet size distributions are obtained for faster cooling rates. We report the droplet size distribution, the behavior of the critical solution temperature as a function of Liquid Crystal content, and some electro-optical properties of different emulsions. The long stability and the electro-optical response show that such systems could be used as promising, low voltage, switchable films.
Taehoo Yoo - One of the best experts on this subject based on the ideXlab platform.
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dye doped cholesteric Liquid Crystal light shutter with a polymer dispersed Liquid Crystal film
Dyes and Pigments, 2016Co-Authors: Jongmi Aek, Joo Heo, Taehoo YooAbstract:Abstract A light shutter, which consists of a dye-doped cholesteric Liquid Crystal (ChLC) layer and a polymer-dispersed Liquid Crystal (PDLC) film, for simultaneous control of haze and transmittance is demonstrated. In the opaque state, it can not only provide a black color by using the dye-doped ChLCs but also hide the objects behind the display panel by using the PDLC film. The proposed light shutter shows a high haze value of 90.7% with a low specular transmittance of 1.20%. By switching the proposed light shutter placed at the back of a see-through display, we can choose between the see-through mode and the high-visibility mode in a see-through display.
Boyu Chen - One of the best experts on this subject based on the ideXlab platform.
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electrically tunable Liquid Crystal core optical channel waveguide
Journal of Lightwave Technology, 2013Co-Authors: Tzyyjiann Wang, Chikai Chaung, Tienjung Chen, Boyu ChenAbstract:We report electrically tunable Liquid-Crystal-core channel waveguides, in which the lightwave guiding can be tuned among cut-off, single-mode, and multi-mode. Ultrasonic-assisted chemical etching is used to produce semicircular grooves on the optical glass substrate for encapsulating Liquid Crystal as the waveguide core. The Liquid-Crystal-core waveguide loss is reduced to the lowest value 1.3 dB/cm up to date, which is attributed to the smooth and uniform groove surface. The extinction ratio is >20 dB for optical switching application. The LC director distributions under various voltages are calculated by finite element method and the characteristics of guided modes are simulated by the full-vectorial mode solver considering the full anisotropy. The simulated waveguide characteristics are well consistent with the experimental results. The proposed Liquid-Crystal-core waveguide owns the features: simple and low-cost fabrication process, arbitrary device pattern, and integration with silicon platform.
Taehoon Yoon - One of the best experts on this subject based on the ideXlab platform.
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vertical alignment nematic Liquid Crystal cell controlled by double side in plane switching with positive dielectric anisotropy Liquid Crystal
Journal of Applied Physics, 2008Co-Authors: Hun Ki Shin, Taehoon YoonAbstract:We propose a vertical alignment Liquid Crystal cell controlled by double-side in-plane switching with a positive dielectric anisotropy Liquid Crystal material. In this structure, the pixel electrodes are interdigital electrodes, which are deposited on the bottom and top substrates parallel to each other. In the voltage-off state, the Liquid Crystal molecules are vertically aligned under the crossed polarizers; hence the cell appears to be dark. When an in-plane field is applied, the Liquid Crystal molecules tilt down to the left or right along the field direction, which is at 45° with respect to the input polarizer, giving rise to maximum transmission of the incident light. We fabricated the proposed cells, which show higher transmittance and lower driving voltage compared with the conventional vertical alignment configuration with a positive dielectric anisotropy Liquid Crystal. The improved electro-optical properties are due to the stronger in-plane field compared with the configuration having one-side ...
