Compound having branched alkyl or branched alkenyl, optically isotropic liquid crystal medium and optical element

Abstract

The first purpose is to provide a liquid crystal compound which is stable to heat, light and so on, and has a high refractive index anisotropy, a high dielectric anisotropy and a low melting point. The second purpose is to provide a liquid crystal medium having a liquid crystal phase which is stable to heat, light and so on, has a wide liquid crystal phase temperature range, a high refractive index anisotropy and a high dielectric anisotropy, and is optically isotropic. The third purpose is to provide optical elements of various types which comprise the liquid crystal medium, are usable over a wide temperature range and have a short response time, a large contrast and a low drive voltage. Disclosed are a liquid crystal compound having branched alkyl or alkenyl, said liquid crystal compound being represented by formula (1), a liquid crystal medium (a liquid crystal composition or a polymer / liquid crystal complex) containing said liquid crystal compound, optical elements comprising said liquid crystal medium, and so on; in formula (1), R1 represents, for example, branched alkyl or branched alkenyl having 3-20 carbon atoms; the rings A1, A2, A3, A4 and A5 represent, for example, 1,4-phenylene or 1,3-dioxan-2,5-diyl; Z1, Z2, Z3 and Z4 independently represent, for example, a single bond or alkylene having 1 to 4 carbon atoms; Y1 represents, for example, fluorine; and m, n and p independently represent 0 or 1, satisfying the requirement 1<=m+n+p<=3.

Description

technical field

[0001] The present invention relates to a liquid crystal compound and a liquid crystal medium useful as a material for an optical element, in particular to a compound with large dielectric anisotropy, refractive index anisotropy and low melting point, and a wide liquid crystal phase temperature range , Liquid crystal media with large dielectric anisotropy and refractive index anisotropy. Furthermore, the present invention relates to an optical element using the liquid crystal medium, and more particularly relates to an optical element which can be used in a wide temperature range, can be driven at low voltage, and can obtain high-speed electro-optical response. Background technique

[0002] A liquid crystal display device using a liquid crystal composition is widely used in displays of clocks, calculators, word processors, and the like. These liquid crystal display elements utilize the refractive index anisotropy, dielectric anisotropy, etc. of liquid crysta...

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