Abstract

A simple method is developed for aligning the laterally difluorinated high birefringence liquid crystal (LC) compounds and mixtures in a homeotropic cell. Adding a few percent positive dielectric anisotropic or nonpolar LC material not only enhances the contrast ratio but also improves the overall figure-of-merit. Several negative LC compounds with a wide variation of birefringence are used to investigate this phenomenon. Molecular modeling and experimentation are demonstrated to support this concept.

© 2005 IEEE

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Appl. Opt. (1)

Other (18)

I. C. Khoo and S. T. Wu, Optics and Nonlinear Optics of Liquid Crystals, Singapore: World Scientific, 1993.

M. G. Clark, E. P. Raynes, R. A. Smith and R. J. A. Tough, "Measurement of the permittivity of nematic liquid crystals in magnetic and electric fields using extrapolation procedures", J. Phys. D: Appl. Phys., vol. 13, pp. 2151-2164, Nov. 1980 .

K. Kim and S. Kim, "Advance of PVA technology for multi-medium applications", in Soc. Inf. Display Tech. Dig., vol. 34, May 2003, pp. 1208 -1211.

K. Okamoto, "Recent development in MVA-LCDs", in Proc. Int. Display Manufacturing Conf., Feb. 2003, pp. 143-146.

M. F. Schiekel and K. Fahrenschon, "Deformation of nematic liquid crystals with vertical orientation in electrical fields", Appl. Phys. Lett. , vol. 19, pp. 391-393, Nov. 1971.

F. J. Kahn, "Orientation of liquid crystals by surface coupling agents", Appl. Phys. Lett., vol. 22, pp. 386-388, Apr. 1973 .

S. T. Wu and D. K. Yang, Reflective Liquid Crystal Displays, Hoboken, NJ: Wiley, 2001.

P. Kirsch and M. Bremer, "Nematic liquid crystals for active matrix displays: Molecular design and synthesis", Angew. Chem. Int. Ed., vol. 39, pp. 4216-4235, Dec. 2000.

D. Pauluth and K. Tarumi, "Advanced liquid crystals for television", J. Mater. Chem., vol. 14, pp. 1219-1227, Mar. 2004.

S. T. Wu, U. Efron and L. D. Hess, "Infrared birefringence of liquid crystals", Appl. Phys. Lett., vol. 44, pp. 1033-1035, June 1984.

S. T. Wu, "Birefringence dispersions of liquid crystals", Phys. Rev. A, vol. 33, pp. 1270-1274, Feb. 1986.

V. Reiffenrath, J. Krause, H. J. Plach and G. Weber, "New liquid crystalline compounds with negative dielectric anisotropy", Liq. Cryst., vol. 5, pp. 159-170, Jan. 1989.

K. Tarumi, M. Bremer and B. Schuler, "Development of new liquid crystal materials for TFT LCDs", IEICE Trans. Electron., vol. E79-C, pp. 1035-1039, Aug. 1996.

M. Klasen, M. Bremer and K. Tarumi, "New liquid-crystal materials for active matrix displays with negative dielectric anisotropy and low rotational viscosity", Jpn. J. Appl. Phys., vol. 39, pp. L1180-L1182, Nov. 2000 .

P. Kirsch and K. Tarumi, "A novel type of liquid crystals based on axially fluorinated cyclohexane units", Angew. Chem. Int. Ed., vol. 37, pp. 484-489, Mar. 1998.

G. W. Gray, M. Hird and K. J. Toyne, "The synthesis of several lateral difluoro-substituted 4, 4' -diakyl-and 4, 4' -alkoxyalkyo-terphenyls and a rationalization of the effect of such substitution on mesophase type and transition temperatures", Mol. Cryst. Liq. Cryst., vol. 204, pp. 43-64, 1991.

S. T. Wu, C. S. Hsu and J. M. Chen, "Room temperature difluoro-tolane and diphenyl-diacetylene liquid crystals with negative dielectric anisotropy", Mol. Cryst. Liq. Cryst. , vol. 304, pp. 441-445, June 1997.

C. H. Wen, S. Gauza, J. Li, H. Wang and S. T. Wu, "High contrast homeotropic alignment of difluoro-tolane liquid crystals", Liq. Cryst., vol. 32, pp. 643 -649, May 2005.

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