Journal ArticleDOI
Temperature independent threshold voltage for an electrooptic effect
TLDR
In this article, the effect of the cholesteric-nematic phase change effect on the helix screw sense was investigated and it was shown that the temperature dependence of the pitch can be compensated by using two chiral compounds, CB 15 and S 811.Abstract:
The threshold voltage of the cholesteric-nematic phase change effect in general decreases considerably with increasing temperature. The temperature dependence for the threshold voltage can be compensated by using an induced cholesteric phase with a helix pitch decreasing sufficiently with increasing temperature. The appropriate temperature dependence of the pitch can be obtained if the nematic phase is doped with two chiral compounds which induce opposite sign of the helix screw sense when used separately. The efficacy of this method was investigated for the two nematic mixtures E 8 and S 1132 to which the two chiral compounds CB 15 and S 811 had been added, the induced pitch values being 3-5 μm. The threshold voltage measured in samples of 23.5 μm and 13 μm thickness using homeotropic boundary conditions are found to be constant within ± 3 % over a temperature range of 50 K.read more
Citations
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Journal ArticleDOI
A new, highly multiplexable liquid crystal display
T. J. Scheffer,J. Nehring +1 more
TL;DR: In this article, a chiral-doped nematic layer with tilted boundaries and a twist angle of ∼270° was used for a 120×240 dot matrix panel multiplexed at a 1/120 duty cycle.
Journal ArticleDOI
Cholesteric liquid Crystals: Physical Properties and Molecular-Statistical Theories
G. S. Chilaya,Longin N. Lisetski +1 more
TL;DR: It seems certain now that cholesteric liquid crystals (cholesterics, or CLC, for short) have been the first examples of mesomorphic state of matter known to humankind.
Book ChapterDOI
Liquid crystals for electro-optic applications
Stephen M. Kelly,Mary O'Neill +1 more
TL;DR: Despite the emergence of competing technologies in flat panel displays, such as light-emitting polymers, LCDs are likely to remain the dominant display devices in the flat panel part of the displays market, at least for the near future and especially for handheld devices as discussed by the authors.
Journal ArticleDOI
Effect of various external factors and pretransitional phenomena on structural transformations in cholesteric liquid crystals
TL;DR: In this article, the effect of an applied electric field on cholesteric structures is studied, and the bistability of the cholesterics-nematic transition, electric field-induced color textures of cholesterol mixtures, and electro-optics of amorphous cholesterolic structures are considered.
References
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Journal ArticleDOI
Effects of electric and magnetic fields on the structure of cholesteric liquid crystals
TL;DR: In this paper, a general method is presented for calculating the structural changes resulting from electric or magnetic fields acting on anisotropy of the anisotropic susceptibility of a liquid crystal.
Journal ArticleDOI
Electric-Field-Induced Phase Change in Cholesteric Liquid Crystals
TL;DR: Optically negative cholesteric liquid-crystal films can be transformed to an optically positive state by applying high d-c electric fields as mentioned in this paper, where the helical structure is converted to either a planar smectic, or a linear nematic, structure.
Journal ArticleDOI
Bistability behavior of texture in cholesteric liquid crystals in an electric field
TL;DR: In this paper, the authors show that the field-induced cholesteric-to-nematic texture transition can show a large hysteresis effect such that at the same field strength, either the Cholesteric or the Nematic texture is stable.
Journal ArticleDOI
Dynamics of liquid‐crystal twist cells
TL;DR: In this paper, the change in molecular orientation with time in liquid-crystal twist cells when the applied field is changed is computed using typical elastic and viscous constants in doped MBBA, without and with a cholesteric twist term.
Journal ArticleDOI
Determination of the Cholesteric Screw Sense
Gerd Heppke,Feodor Oestreicher +1 more
TL;DR: In this article, a cholesteric liquid crystal is placed between a glass plate with planar alignment and a spherical lens with concentric surface alignment, and a double spiral disclination line appears.
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