Disclosed are a liquid crystal composition, a liquid crystal display element, and a liquid crystal display, said liquid crystal composition comprising one or more compounds represented by formula I, one or more compounds represented by formula II, one or more compounds represented by formula III and one or more compounds represented by formula IV,

##STR00001##

The liquid crystal composition of the present invention has a good stability to light and heat and a lower viscosity, and can attain a wider refractive index and a high clearing point (a wide service temperature range), and in particular, the liquid crystal composition has a high light transmittance, thus allowing a display device to have a high brightness or an energy saving effect.

A liquid crystal display including a first substrate, a second substrate disposed opposite the first substrate, and a liquid crystal layer disposed between the first substrate and the second substrate. The liquid crystal layer includes a liquid crystal composition. The liquid crystal composition includes at least one of liquid crystal compounds including a cyclopentadienyl group.

A liquid crystal display device includes a liquid crystal panel that includes a liquid crystal layer containing a liquid crystal composition; and a light source that emits light on the liquid crystal panel, the liquid crystal composition containing at least one of a first liquid crystal compound containing a phenyl group and a conjugated bond group that forms a conjugated system continuous with the phenyl group and a second liquid crystal compound containing an alkenyl group not forming a conjugated system, the light source emitting green light having a half width of less than 50 nm.

A liquid crystal medium containing a compound of formula I ##STR00001## and one or more compounds of the formulae IIA, IIB, IIC and IID, ##STR00002## useable in optical, electro-optical and electronic purposes, in particular in LC displays.

Compounds of formula I, ##STR00001##
in which X.sup.1, X.sup.2, Sp, and R are as defined herein, are suitable for use in liquid-crystal media, such as liquid-crystal media used in liquid-crystal displays.

A liquid crystal composition, including at least one of: a first compound represented by Chemical Formula 1 below, a second compound represented by Chemical Formula 2 below; and a third compound represented by Chemical Formula 2 below: ##STR00001## The definitions of A, Z, n, R, and R are provided herein. Also provided is a liquid crystal display, including: a first display panel including a thin film transistor; a second display panel facing the first display panel; and a liquid crystal layer including at least one of a first compound represented by Chemical Formula 1, a second compound represented by Chemical Formula 2, and a third compound represented by Chemical Formula 2 and a reactive mesogen.

A liquid crystal display includes a first substrate, a second substrate opposing the first substrate, an electrode portion provided on at least one of the first and second substrates, and a liquid crystal layer provided between the first substrate and the second substrate and including a liquid crystal composition. The liquid crystal composition includes a liquid crystal compound including a cyclohexenylene group, and provides the liquid crystal display with low rotary viscosity and high voltage holding ratio.

Provided are a polymerizable composition of a polymerizable compound represented by formula I and a polymerizable compound represented by formula II, a liquid crystal composition formed by combining this polymerizable composition with a specific liquid crystal component, particularly a PSVA liquid crystal composition suitable for display or TV applications, and a PSA-IPS liquid crystal composition for an IPS mode; in particular, the polymerizable liquid crystal composition has a good solubility, and an adjustable rate of polymerization and morphology after polymerization; furthermore, a material system formed from the selected polymerizable component and liquid crystal component has a low rotary viscosity and good photoelectric properties, and has a high VHR after (UV) photoradiation, this avoiding the problems of the occurrence of afterimages in final displays, etc.

A nematic liquid crystal composition has negative dielectric anisotropy and contains at least one polar compound selected from the group of compounds represented by formula (1) as a first additive, and the liquid crystal display device includes the composition. In formula (1), R.sup.1 is hydrogen, halogen, alkyl having 1 to 12 carbons or the like; R.sup.2 is a group represented by OH, OR.sup.0, NH.sub.2, NHR.sup.0 or N(R.sup.0).sub.2, in which R.sup.0 is alkyl having 1 to 5 carbons; ring A and ring B are independently 1,4-cyclohexylene, 1,4-phenylene or the like; Z.sup.1 is a single bond or the like; Sp.sup.1 and Sp.sup.2 are independently a single bond, alkylene having 1 to 7 carbons or the like; and a is 0 to 4. ##STR00001##

The present invention relates to a liquid-crystalline medium based on a mixture of polar compounds having negative dielectric anisotropy (), which is distinguished by the fact that it has a value for the ratio .sub.1/n.sup.2 in the range 6-45 with a clearing point of >60 C. and a of 2.3. Media of this type are particularly suitable for electro-optical displays having active-matrix addressing based on the ECB, PA LCD, FFS or IPS effect.