The invention relates to a liquid-crystalline medium, preferably having a nematic phase and dielectric anisotropy of 0.5 or more, which comprises one or more compounds of formula Y ##STR00001##
in which the parameters have the meanings given in the text,
to the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type, and to the use of the compounds of formula Y for the improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.

The invention relates to a liquid-crystalline medium, preferably having a nematic phase and dielectric anisotropy of 0.5 or more, which comprises one or more compounds of formula YX

##STR00001## in which
the parameters have the meanings given in the text,
to the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type, and to the use of the compounds of formula YX for the improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds.

The problem is to provide a polymerizable compound having suitable polymerization reactivity, a high conversion ratio, low polymerization starting temperature, and high solubility in a liquid crystal composition; a liquid crystal composition containing the compound; and a liquid crystal display device including the composition.

A means thereof includes a compound represented by formula (1) and a liquid crystal composition containing the compound.

##STR00001##

In formula (1), R.sup.1, R.sup.2 and R.sup.3 are independently alkyl or the like; n is 0 or the like; ring A.sup.1 is phenyl or the like, and ring A.sup.2 and ring A.sup.3 are independently 1,4-phenylene or the like; Z.sup.1 and Z.sup.2 are independently a single bond or the like; Sp.sup.1 to Sp.sup.4 are a single bond or the like; a is 1 or the like; c, d and e are independently 0 or 1, and a sum of c, d and e is 1 or the like; and P.sup.1 to P.sup.4 are a polymerizable group, and at least one of P.sup.1 to P.sup.4 is a polymerizable group represented by formula (P-1).

##STR00002##

Self-aligned liquid crystal materials and structures are disclosed. The structures can exhibit piezoelectric and flexoelectric properties.

The present invention provides a liquid crystal composition comprising one or more compounds of general formula I and one or more compounds of general formula II; the liquid crystal composition of the present invention can work at very high and very low temperatures, has a very short response time and a better reliability to light and heat, and particularly exhibits no image retention or a significantly reduced image retention after a long time operation.

Provided are a liquid-crystal-medium having stability to heat, light and so forth, a wide liquid-crystal-phase temperature-range and significantly large dielectric-anisotropy and developing an optically isotropic liquid-crystal-phase; and various optical-devices used in a wide temperature-range, having short response-time, a large contrast-ratio and low drive-voltage and suppressing decrease in an effective dielectric-constant in a high-frequency range. A Liquid-crystal composition contains achiral-component T containing at least one compound selected from a first component represented by formula (1) and at least one compound selected from a second component represented by formula (2) or (3) and a chiral-agent to develop optically-isotropic liquid-crystal-phase: ##STR00001##
In formula (1), R.sup.1: alkyl, ring A.sup.1: 1,4-cyclohexylene, ring B.sup.1: 1,4-phenylene, L.sup.11 to L.sup.14: fluorine, Y.sup.1: fluorine, n.sup.1: 1 or 2, R.sup.2: alkyl, Z.sup.21 and Z.sup.22: single-bond or CF.sub.2O, L.sup.21 to L.sup.23: fluorine, Y.sup.2: fluorine, R.sup.3: alkyl, Z.sup.31 and Z.sup.32: single-bond or CF.sub.2O, L.sup.31 to L.sup.34: fluorine, Y.sup.3: fluorine, for example.

The present application relates to a device for regulating the passage of light which is characterised in that it comprises a layer comprising a liquid-crystalline mixture containing a characteristic structural element.

Compounds that have ultraviolet light absorbing properties, and which can also have mesogenic properties. Compositions that include one or more such compounds. Articles of manufacture that include one or more such compounds, such as optical elements that include an optical substrate and a layer that includes at least one such compound.

Self-aligned liquid crystal materials and structures are disclosed. The structures can exhibit piezoelectric and flexoelectric properties.

The present invention provides, by using a photo-alignment film, a liquid crystal display device in which a good voltage holding ratio is retained for a long period of time and occurrence of image sticking and stain in a display screen is prevented. The liquid crystal display device of the present invention includes an active matrix liquid crystal panel and a backlight, the liquid crystal panel including a liquid crystal layer, a pair of substrates that sandwich the liquid crystal layer in between, and an alignment film disposed on a liquid crystal layer side surface of each of the substrates, each alignment film being a photo-alignment film formed from a material that exhibits a photo-alignment characteristic and containing carboxyl groups on the liquid crystal layer side, the liquid crystal layer containing a liquid crystal material and a nitrobenzene derivative.