A positive dielectric anisotropic liquid crystal composition includes one or more compounds of formula I and one or more compounds of formula II: ##STR00001##
wherein R1 represents cyclopropyl, cyclobutyl or cyclopentyl, R2, R3 and R4 are as defined in the specification, and a liquid crystal display device. The liquid crystal composition has positive dielectric properties, a high charge retention ratio, a low rotary viscosity, a fast response time, and especially a high transmittance, and is suitable for manufacturing a TFT-LCD with a high transmittance and a fast response.

A liquid crystal composition includes one or more compounds of general Formula I in an amount of 1%-30% by weight of the total weight of the liquid crystal composition, one or more compounds of general Formula II in an amount of 5%-35% by weight of the total weight of the liquid crystal composition, and one or more compounds of general Formula III in an amount of 1%-35% by weight of the total weight of the liquid crystal composition. The liquid crystal composition has an appropriate clearing point, an appropriate optical anisotropy, an appropriate dielectric anisotropy, as well as a higher voltage holding ratio, a higher transmittance, a good high-temperature resistant performance and a faster response speed, thus being suitable for display modes, such as VA, IPS and FFS. A photoelectric display device includes the liquid crystal composition. ##STR00001##

Aromatic isothiocyanates of formula C

##STR00001##

liquid-crystalline media comprising one or more compounds of formula C, and high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas, e.g. phased array antennas.

A liquid crystal mixture applied in light modulating devices includes at least one compound selected from the group of compounds of formula I, at least one compound selected from the group of compounds of formula II and/or formula III, and at least one chiral compound. A light modulating device includes the liquid crystal mixture, where the light modulating device has reduced haze in the transparent state while increased opacity in the light scattering state.
R.sub.1-MG.sub.1-X-MG.sub.2-R.sub.2  I ##STR00001##

The invention relates to bimesogenic compounds of formula I

##STR00001##

to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.

To provide a liquid crystal composition having at least one or a suitable balance regarding two of characteristics such as high maximum or low minimum temperature of a nematic phase, small viscosity, suitable optical anisotropy, large dielectric anisotropy, large specific resistance, high stability to ultraviolet light or heat and a large elastic constant; and an AM device including the composition and having a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio, a long service life and so forth. The liquid crystal composition contains a quencher as an additive component and a specific compound having large positive dielectric anisotropy as a first component, and a liquid crystal display device includes the composition. The composition may contain a specific compound having high maximum temperature or small viscosity as a second component, or a specific compound having negative dielectric anisotropy as a third component.

To provide a liquid crystal composition having at least one or a suitable balance regarding two of characteristics such as high maximum or low minimum temperature of a nematic phase, small viscosity, suitable optical anisotropy, large dielectric anisotropy, large specific resistance, high stability to ultraviolet light or heat and a large elastic constant; and an AM device including the composition and having a short response time, a large voltage holding ratio, low threshold voltage, a large contrast ratio, a long service life and so forth. The liquid crystal composition contains a quencher as an additive component and a specific compound having large positive dielectric anisotropy as a first component, and a liquid crystal display device includes the composition. The composition may contain a specific compound having high maximum temperature or small viscosity as a second component, or a specific compound having negative dielectric anisotropy as a third component.

Provided is a polar compound having high chemical stability, high capability of aligning liquid crystal molecules, high solubility in a liquid crystal composition, and a large voltage holding ratio when used in a liquid crystal display device. The compound is represented by formula (1):

##STR00001##

in which, for example, R.sup.1 is alkyl having 1 to 15 carbons; MES is a mesogen group having at least one ring; Sp.sup.1 is a single bond or alkylene having 1 to 10 carbons; M.sup.1 and M.sup.2 are hydrogen; and R.sup.2 is a group represented by formulas (1a) to (1c):

##STR00002##

in which, Sp.sup.2 and Sp.sup.a are a single bond or alkylene having 1 to 10 carbons; S.sup.1 is >CH—; S.sup.2 is >C<; and X.sup.1 is —OH.

The present invention relates to a reverse wavelength dispersion compound, a reverse wavelength dispersion composition including the same, and an optically anisotropic body including the same. The reverse wavelength dispersion composition according to the present invention can provide a stronger and more stable reverse wavelength dispersion property, and makes it possible to provide an optically anisotropic body having excellent optical properties.

A polar compound has a high chemical stability, high ability to align liquid crystal molecules and high solubility in a liquid crystal composition, and causes no decrease of liquid crystallinity of the liquid crystal composition, a liquid crystal composition contains the compound, and a liquid crystal display device includes the composition. The compound is represented by formula (1), the composition contains the compound, and the liquid crystal display device uses the composition. ##STR00001## In formula (1), R.sup.1 is alkyl having 3 to 15 carbons, alkenyl having 4 to 15 carbons or the like; a is an integer from 2 to 12; and R.sup.2 is a group represented by formula (1a), formula (1b) or formula (1c). ##STR00002## In the formulas, S.sup.1 and S.sup.2 are independently a single bond, alkylene having 1 to 10 carbons; S.sup.3 is >CH— or >N—; S.sup.4 is >C< or >Si<; and X.sup.1 is —OH, —NH.sub.2 or the like.