The present invention relates to the liquid crystal field, and particularly relates to a liquid crystal composition and use thereof in the liquid crystal display field. The liquid crystal composition of the present invention comprises, in percentages by weight, 5-40% of one or more compounds represented by general formula I, 2-30% of one or more compounds represented by general formula II, and 20-70% of one or more compounds represented by general formula III, and may further comprise 4-30% of one or more compounds represented by general formula IV and/or 5-25% of one or more compounds represented by general formulas V to IX. The combined use of the above-mentioned compounds can effectively reduce the rotational viscosity of the liquid crystal composition, improves related properties of the mixed liquid crystal, and thus reduces the response time thereof. The liquid crystal composition of the present invention can be used for a fast-response liquid display in a variety of display modes.

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.

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I,

##STR00001##

in which
R.sup.1, R.sup.1*, Z.sup.1, Z.sup.2 and L.sup.1-3 have the meanings defined herein,
and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, PS-IPS or IPS effect.

To show a liquid crystal compound satisfying at least one of physical properties such as high chemical stability, a high clearing point, a low minimum temperature of a liquid crystal phase, low viscosity, large optical anisotropy, large dielectric anisotropy, a suitable elastic constant and excellent compatibility with other liquid crystal compounds, a liquid crystal composition containing the compound and a liquid crystal display device including the composition. A compound is represented by formula (1). ##STR00001##

Provided is a polar compound that has high chemical stability and high capability of aligning liquid crystal molecules, and has a large voltage holding ratio when used in a liquid crystal display device.

The compound represented by formula (1) is applied.

##STR00001##

For example, R.sup.1 is alkyl having 1 to 15 carbons; rings A.sup.1 to A.sup.5 are 1,4-cyclohexylene or 1,4-phenylene; Z.sup.1 and Z.sup.5 are a single bond or alkylene having 1 to 10 carbons; a and b are 0 to 4, and a sum of a and b is 4 or less; d is 1 to 4; c and e are 0 to 4; P.sup.1 to P.sup.3 are a polymerizable group represented by formulas (P-1) to (P-5):

##STR00002##

in which M.sup.1 to M.sup.3 are hydrogen or alkyl having 1 to 5 carbons; and R.sup.2 is a group represented by formulas (1a) to (1c):

##STR00003##

in which Sp.sup.1 to Sp.sup.5 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 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.

An object of the present invention is to provide a dye compound-containing liquid crystal composition that has high solubility and high solubility retention for the dye compound and has high light resistance and a device including the composition. The use of a combination of one or two or more predetermined alkenyl compounds and a compound including a predetermined difluoro structure can provide a dye compound-containing liquid crystal composition that has high solubility and high solubility retention for the dye compound and has high light resistance, and the dye compound-containing liquid crystal composition is useful for devices, in particular, photochromic devices.

Provided is a compound having an effect on preventing photolysis of a liquid crystal composition and having a high solubility in the liquid crystal composition, a liquid crystal composition containing the compound and a liquid crystal display device including the composition. The compound is represented by formula (1), the liquid crystal composition contains the compound, and the liquid crystal display device uses the composition: ##STR00001##
wherein in formula (1), R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently hydrogen or alkyl having 1 to 4 carbons; R.sup.5 is hydrogen, hydroxy, oxy radical, alkyl having 1 to 10 carbons or alkoxy having 1 to 10 carbons; ring A.sup.1 is 1,4-cyclohexylene, 1,4-cyclohexenylene or the like; Z.sup.1 and Z.sup.2 are independently a single bond or alkylene having 1 to 10 carbons; and a is 0, 1, 2 or 3.

A solution is a compound represented by formula (1), a liquid crystal composition containing the compound and a liquid crystal display device including the composition. ##STR00001## In formula (1), R.sup.a and R.sup.b are independently alkyl having 1 to 30 carbons or the like; and X and Y are independently fluoroalkyl having 1 to 5 carbons, fluoroalkoxy having 1 to 5 carbons or pentafluorosulfanil, and one of X and Y may be fluorine.

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.