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Full-Text Articles in Engineering
Electric Field Induced Biaxiality And The Electro-Optic Effect In A Bent-Core Nematic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, U. Manna, J. K. Vij, C. Keith, C. Tschierske
Electric Field Induced Biaxiality And The Electro-Optic Effect In A Bent-Core Nematic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, U. Manna, J. K. Vij, C. Keith, C. Tschierske
Articles
We report the observation of a biaxial nematic phase in a bent-core molecular system using polarizing microscopy, electro-optics, and dielectric spectroscopy, where we find that the biaxiality exists on a microscopic scale. An application of electric field induces a macroscopic biaxiality and in consequence gives rise to electro-optic switching. This electro-optic effect shows significant potential in applications for displays due to its fast high-contrast response. The observed electro-optic switching is explained in terms of the interaction of the ferroelectric clusters with the electric field. © 2010 American Institute of Physics.
Liquid Crystal Display Modes In A Nontilted Bent-Core Biaxial Smectic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, J. K. Vij, C. Keith, C. Tschierske
Liquid Crystal Display Modes In A Nontilted Bent-Core Biaxial Smectic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, J. K. Vij, C. Keith, C. Tschierske
Articles
Liquid crystal display (LCD) modes associated with the rotation of the secondary director in nontilted, biaxial smectic phase of an achiral bent-core compound are demonstrated. For LCDs, we find that at least four display modes are possible using SmAPA phase of the studied material, in which the minor directors in adjacent layers are aligned antiferroelectrically. The advantages of these modes include low driving field (1–2 V/ µm), high contrast ratio 1000:1, relatively fast switching time of 0.5 ms and continuous gray scale. The molecular short axis or the polar axis in a negative dielectric, biaxial material is oriented by the …
V-Shaped Electro-Optic Response Observed In A Chiral Ferroelectric Smectic Liquid Crystal, V. Manjuladevi, Yuri Panarin, Jang-Kun Song, B. K. Sadashiva
V-Shaped Electro-Optic Response Observed In A Chiral Ferroelectric Smectic Liquid Crystal, V. Manjuladevi, Yuri Panarin, Jang-Kun Song, B. K. Sadashiva
Articles
We report on the observation of V-shaped switching in a ferroelectric liquid crystal cell over a wide range of temperatures. Results of the optical transmittance in the visible region give us the helical pitch for various temperatures of the ferroelectric liquid crystalline compound used. We show that the helical pitch, in addition to the spontaneous polarization (PS) and thickness of the alignment layer of the cell, is an important factor in giving V-shaped switching. A longer or helical compensated mixture gives a better V-shaped switching. © 2008 American Institute of Physics.
Discontinuous Change In The Smectic Layer Thickness In Ferrielectric Liquid Crystals, V. P. Panov, J. K. Vij, Yuri Panarin, C. Blanc, V. Lorman, J. W. Goodby
Discontinuous Change In The Smectic Layer Thickness In Ferrielectric Liquid Crystals, V. P. Panov, J. K. Vij, Yuri Panarin, C. Blanc, V. Lorman, J. W. Goodby
Articles
The temperature dependence of the thickness of thick free-standing films is studied using a high-resolution film thickness measurement technique. A small discontinuity in the temperature dependence of the smectic layer thickness at every phase transition between ferro-, ferri-, and antiferroelectric phases is observed. We show that the major contribution to it arises from a change in the smectic tilt angle.
Experimental Study For The Conditions Of Analog Switching In Ferroelectric Liquid Crystal Cells, V. Manjuladevi, Yuri Panarin, J.K. Vij
Experimental Study For The Conditions Of Analog Switching In Ferroelectric Liquid Crystal Cells, V. Manjuladevi, Yuri Panarin, J.K. Vij
Articles
The authors study the effect of the spontaneous polarization (PS) of a ferroelectric liquid crystal mixture with compensated helix and of the thickness of the alignment layer (da) on the analog switching in a cell. The quality of analog switching is established in terms of its contrast ratio, texture in the dark state, and the electrostatic energy. The latter approximates to PS 2da for da
Observation And Investigation Of The Ferrielectric Subphase With High Qt Parameter, Yuri Panarin, O. Kalinovskaya, J.K. Vij, J.W. Goodby
Observation And Investigation Of The Ferrielectric Subphase With High Qt Parameter, Yuri Panarin, O. Kalinovskaya, J.K. Vij, J.W. Goodby
Articles
Dielectric relaxation processes in an antiferroelectric liquid crystal (AFLC) have been investigated over a wide range of frequencies from 1 Hz to 1 GHz. The AFLC under investigation possesses a variety of different ferrielectric, ferroelectric, and antiferroelectric phases. Dielectric and polarization measurements under direct bias voltage have been made with a view to clarifying the origin of the high-temperature ferrielectric phase, which appears between the AF and smectic-C phases. This phase is assigned to an unstable ferrielectric phase with qT parameter greater than 1/2 (according to the Ising model) or a doubly modulated incommensurate phase (according to the expanded Landau …
Observation And Investigation Of The Ferrielectric Subphase With Qt>1/2, Yuri Panarin, O. Kalinovskaya, J. K. Vij
Observation And Investigation Of The Ferrielectric Subphase With Qt>1/2, Yuri Panarin, O. Kalinovskaya, J. K. Vij
Articles
The high-temperature femelectric phase with qT > 1/2 has been found to exist in a antiferroelectric liquid crystal. This phase has been identified using dielectric spectroscopy and conoscopy.