Hybrid aligned nematics

C.-W. Kuo, S.-C. Jeng, H.-L. Wang, C-.C. Liao, Application of nanoparticle-induced vertical alignment in hybrid-aligned nematic liquid crystal cell. Appl. Phys. Lett. 91, 141103 (2007)... 

It has also been used to study the second sound resonance in smectic A liquid crystals and measure the compression modulus. For measuring the flexocoefficients (ei — 63) and (ei + 63), hybrid-aligned nematic cells have been used extensively. AC techniques avoid problems associated with ionic impurities, but require elaborate numerical fitting of the data. Some observations on the pnblished measurements of flexo-coefHcients are made in Section 2.4, which ends with a few concluding remarks. 

Fig. 2.2. Schematic diagram of a hybrid-aligned nematic cell. The field-free director (shown by the continuous curved line) has a splay-bend curvature distortion in the xz plane. A DC field applied along the y axis rotates the polarization and the director (shown by the curved dashed line) acquires a 4>(z) profile. (Reproduced from Dozov et al. with the permission of EDP Sciences, http //publications.edpsciences.org.)...

N.V. Madhusudana and G. Durand, Linear flexo-electro-optic effect in a hybrid aligned nematic liquid crystal cell, J. Physique Lett. 46(5), L-195-L-200, (1985). doi 10.1051/jphyslet 01985004605019500... 

N.T. Kirkman, T. Stirner and W.E. Hagston, Continuum modelling of hybrid-aligned nematic liquid crystal cells optical response and flexoelectricity-induced voltage shift, Liq. Cryst. 30(9), 1115-1122, (2003). doi 10.1080/02678290310001594562... 

S.A. Jewell and J.R. Sambles, Fully leaky guided mode study of the flexoelectric effect and surface polarization in hybrid aligned nematic cells, J. Appl. Phys. 92(1), 19-24, (2002). doi 10.1063/1.1483392... 

T.S. Taphouse, S.L. Cornford, J.E. Birkett and J.R. Sambles, Time-resolved sign-dependent switching in a hybrid aligned nematic liquid crystal cell. New J. Phys. 10(8), 083045/1-15, (2008). 

P.R. Maheswara Murthy, V.A. Raghunathan and N.V. Madhusudana, An AC electro-optic technique of comparing the two anchoring energies of a hybrid aligned nematic cell, Liq. Cryst. 14(4), 1107-1124, (1993). 

Flexoelectric patterns also exist for nematic layers with asjrmmetric boundary conditions, i.e. with homeotropic anchoring on one surface and planar anchoring on the other one hybrid-aligned nematics).The critical voltage and the critical wave number obtained with the one-elastic-constant approximation are in a good agreement with experimental re-sults. ... 

Fig. 7.15. The vertically aligned nematic-hybrid aligned nematic (VAN-HAN) zenithal bistable device geometry. The homeotropic state (left) is black while the hybrid state (right) is bright.

A. Mazzulla, F. Ciuchi and J.R. Sambles, Optical determination of flexoelectric coefficients and surface polarization in a hybrid aligned nematic cell, Phys. Rev. E 64(2), 021708/1-6, (2001). doi 10.1103/PhysRevE.64.021708... 

Bent-core liquid crystalline elastomer Bent-core nematic swollen in a liquid crystal elastomer Black lipid membranes Direct current Electroconvection Electrohydrodynamic Ferroelectric liquid crystal Hybrid-aligned nematic Human embryonic kidney Isotropic... 

Y. Lu, X. Liang, Y. H. Wu, et al.. Dual-frequency addressed hybrid-aligned nematic liquid crystal, Appl Phys. Lett. 85, 3354 (2004). 

T. Uesaka, E. Yoda, T. Ogasawara, and T. Toyooka, Optieal design for wide-viewing-angfe transflective TFT-LCDs with hybrid aligned nematic compensator, Proc. 9th Int L Display Workshops, pp. 417-420 (2002). 

S. H. Lee, K. H. Park, J. S. Gwag, et al., A multimode-type transfleetive liquid crystal display using the hybrid-aligned nematic and parallel-mbbed vertically aUgned modes, Jpn. J. Appl. Phys., part 1, 42, 5127 (2003). 

Hybrid Aligned Nematics, Appl. Phys. Lett. (19S2) 162... 

Enhanced nonlinear birefringence in hybrid aligned nematics... 

FIG. 1. Schematic representation of the hybrid aligned nematic (HAN) cell with no applied field. The rod lines show the alignment of the director n at different points in the cell. 

The flexoelectric distortion in Hybrid Aligned Nematic (HAN) configuration was studied [190, 191]. In HAN cells the director is homeotropic on one of the substrates and homogeneous on the other. The measme-ments of transmitted intensity in HAN samples allow us to evaluate for MBBA both a nematic anchoring energy W for the homeotropic orientation VF 6 X 10 erg/cm and the sum of the flexoelectric moduli 11 + 33 —4.5 X 10 dyn / [191]- In an electric field normal to the initial director plane, the flexoelectric effect results in the appearance of twist deformation, observed by the rotation of linearly polarized light [190]. 

VA Vertical aligned nematic MVA Multi vertical aligned nematic HAN Hybrid aligned nematic... 

A. Sparavigna, L. Komitov, B. Stebler, and A. Strigazzi, Static splay-stripes in a hybrid aligned nematic layer. Mol. Cryst. Liq. Cryst., 207, 265 [1991]. 

G. Barbero and R. Barberi, Critical thickness of a hybrid aligned nematic liquid crystal cell,/. Phys., 44, 609 [1983]. 

D. Krzyzanski and G. Derfel, Structure of periodic deformations in hybrid aligned nematic layers, Phys. Rev. E, 63, 021702 (2001). 

Guillen, A.D. Mendoza, C.I. (2007). Influence of an electric field on the non-Newtonian response of a hybrid-aligned nematic cell under shear flow. The Journal of Chemical Physics, Vol. 126, pp. 204905-1-204905-9 Guillen, A.D. Mendoza, C.I. (2007). Erratum Influence of an electric field on the non-Newtonian response of a hybrid-aligned nematic cell under shear flow. The Journal of Chemical Physics, Vol. 127, pp. 059901-1-059901-2... 

---