A liquid crystal display device comprises a first substrate, a second substrate which faces the first substrate, an electrode part which is provided on at least one of the first substrate and the second substrate, and a liquid crystal layer which comprises a liquid crystal composition and is provided between the first substrate and the second substrate. The liquid crystal composition includes a liquid crystal compound of Formula 1. ##STR00001##
wherein R.sub.1, R.sub.2, A.sub.11, A.sub.12, A.sub.13, A.sub.21, A.sub.22, Z.sub.11, Z.sub.12, Z.sub.13, Z.sub.21, Z.sub.22, a, b, c, d, and e are as described herein.

The present invention relates to mesogen compounds that include a first mesogen (Mesogen-1) and a second mesogen (Mesogen-2) that are connected by a linking group (-L-), as represented by the following Formula (I):

##STR00001##

Mesogen-1, and optionally Mesogen-2, each independently include the following terminal group,

##STR00002##

where R is hydrogen, alkyl, or alkoxy. Mesogen-2 optionally includes a terminal group P-, which is selected from R, acrylate, methacrylate, trihalomethacrylate, oxirane, hydroxyl, carboxylic acid, and carboxylic acid ester. Mesogen-1 and Mesogen-2 together include a total of at least seven, or at least eight, cyclic groups. In some cases, Mesogen-1 and Mesengen-2 are the same. The present invention also relates to liquid crystal compositions that include such mesogen compounds, and to optical elements that include such mesogen compounds.

The present invention relates to a PSA-mode liquid crystal display device including a polymer produced by polymerizing a polymerizable compound by energy ray irradiation in a state in which a mixture of the polymerizable compound and a liquid crystal composition is held between the first substrate and the second substrate, the polymer having a number-average molecular weight of 50,000 or more in terms of polystyrene. In a PSA-mode display device in which alignment of liquid crystal molecules substantially vertically aligned between the substrates is controlled by applying a voltage, a pre-tilt angle can be properly given without being inhibited. Therefore, the present invention provides a PSA-mode display device with good alignment stability, uniform alignment within the substrates, and no or suppressed display defects and a method for producing the same.

The invention relates to liquid-crystalline mixtures comprising at least one compound of the formula I, ##STR00001##
in which
X, L.sup.1, L.sup.2, L.sup.3, L.sup.4 and alkenyl have the meanings indicated in claim 1,
in order to increase the pretilt at the polyimide surface,
and to
liquid-crystalline media comprising one or more compounds of the formula I in electro-optical liquid-crystal displays and in LC lenses.

The invention relates to liquid-crystalline mixtures comprising at least one compound of the formula I, ##STR00001##
in which
X, L.sup.1, L.sup.2, L.sup.3, L.sup.4 and alkenyl have the meanings indicated in claim 1,
in order to increase the pretilt at the polyimide surface,
and to
liquid-crystalline media comprising one or more compounds of the formula I in electro-optical liquid-crystal displays and in LC lenses.

A compound having a maximum absorption in a wavelength range of 350 nm to 550 nm that functions as a dichroic dye is provided. In particular, a compound represented by formula (1) is provided. In the compound of formula (1), R.sup.1 represents a hydrogen atom or the like; R.sup.2 represents a hydrogen atom or the like; R.sup.3 represents a hydrogen atom or the like; Z represents —CO— or the like; and Y represents a group of formula (Y1). In the group of formula (Y1), * represents a bonding site with N, or a group of formula (Y2); and in the group of formula (Y2), * represents a bonding site with N; P.sup.1 and P.sup.2 each independently represent —S— or the like; and Q.sup.1 and Q.sup.2 each independently represent ═N— or the like.

##STR00001##

A liquid crystal composition is described, containing a chiral agent and achiral component T containing at least one compound 1 having an unsubstituted or methyl group-substituted dioxane ring and having at least one —COO— or —CF.sub.2O— as a connecting group, and exhibiting an optically isotropic liquid crystal phase.

A liquid crystal composition is described, containing a chiral agent and achiral component T containing at least one compound 1 having an unsubstituted or methyl group-substituted dioxane ring and having at least one —COO— or —CF.sub.2O— as a connecting group, and exhibiting an optically isotropic liquid crystal phase.

The disclosure provides a liquid crystal display (LCD) panel, a manufacturing method thereof, and an LCD device. The LCD panel adopts a structure with multiple electrodes and dual-frequency liquid crystals. When a temperature of the LCD panel is low (below 0° C.), the LCD panel is driven at high frequency, so that it emits more heat. Therefore, a working temperature of the LCD panel is increased without adding a heating element. LCD devices using such LCD panels have wide working temperature ranges, and are well suited to be used outdoors.

The present invention discloses a liquid crystal composition, comprising: at least a first compound selected from the group consisting of a compound of general Formula I-1, a compound of general Formula I-2, and a combination thereof, and at least a second compound selected from the group consisting of a compound of general Formula II-1, a compound of general Formula II-2, a compound of general Formula II3, a compound of general Formula II-4 and a combination thereof The liquid crystal composition provided in the present invention has the properties of appropriate optical and dielectric anisotropies, high clearing point, existence of a nematic phase over a wide range of temperature, low viscosity and good high-temperature stability. The liquid crystal composition is applicable to a liquid crystal display (LCD) device, to enable the LCD device to have such properties as short response time, excellent display effect at high temperature, and others.

##STR00001##