To provide a liquid crystal display device that has a high off-response speed and a good balance between drive voltage and transmittance, is stable over time, and also has a high voltage holding ratio. A liquid crystal display device in which a liquid crystal layer containing a polymer network (A) and a liquid crystal composition (B) is disposed between two substrates having an electrode on at least one side thereof and having transparent properties on at least one side thereof, and the loss factor (tan δ) (loss modulus/storage modulus) of the liquid crystal layer calculated from the storage modulus (Pa) and the loss modulus (Pa) in a sinusoidal vibration measured with a rheometer at 25° C. and at a measurement frequency of 1 Hz ranges from 0.1 to 1.

The invention relates to novel compositions comprising at least two anisotropic compounds of formula

##STR00001##

as well as to liquid crystalline networks, films and electro-optical devices comprising the compositions.

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 the compound is used in a liquid crystal display device; and a composition containing the compound. The compound is represented by formula (1). In formula (1), for example, P.sup.1 is a group represented by any one of formulas (1b) to (1i), P.sup.2 is a group represented by formula (1d), Sp.sup.1 and Sp.sup.2 are a single bond, Z.sup.1, Z.sup.2, Z.sup.3, Z.sup.4 and Z.sup.5 are —COO—, and ring A.sup.1, ring A.sup.2, ring A.sup.3 and ring A.sup.4 are 1,4-phenylene: ##STR00001##

A polymer having excellent liquid crystal alignment and electrical properties and thus is suitable for use as a liquid crystal alignment agent, a liquid crystal alignment agent including the same, a liquid crystal alignment film formed from the liquid crystal alignment agent, and a liquid crystal display device including the liquid crystal alignment film are provided.

The present invention relates to polymers that include residues of at least one monomer represented by the following Formula (I). With reference to Formula (I), at least one of E1 and E2 independently is, or is independently substituted with, at least one reactive group, such as a (meth)acryloyl group. Monomers represented by Formula (I) and monomer residues thereof have alignment properties, such as photoalignment properties. The present invention also relates to alignment layers that include such polymers, and articles of manufacture, such as optical elements, that include one or more such alignment layers. ##STR00001##

A series of 8-(bisphenylethynyl)-ester flexible multiple ring-containing fluoroboron pyrrole liquid crystal dyes are synthesized by introducing a diphenylethynyl rigid structure at position 8 of a boron-dipyrromethene core via a Sonogashira coupling reaction, and a flexible multiple ring such as bicyclohexane, or cholesterol is connected to the biphenylethynyl via an esterification reaction. The dye compounds all have maximum emission wavelengths in methylene chloride concentrated around 525 nm, present green fluorescence, and show good dichroic colour ratios and ordered parameters in E7 liquid crystal. The liquid crystal compounds are in a liquid crystal intermediate phase within the range of 100-280° C., and may be used for manufacturing liquid crystal display products, especially as guest dyes for guest-host mode liquid crystal displays. The response time can be improved and a rapid response effect achieved when the compounds are added to E7 liquid crystal and used for a guest-host display mode.

An optically anisotropic layer is formed by a liquid crystal compound represented by General Formula 1, in which the long axes of the molecules are oriented. ##STR00001##
wherein L.sub.1 and L.sub.2 independently represent a linking group having a carbonyl group; F.sub.1 and F.sub.2 independently represent an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom; n and m independently represent an integer from 0 to 4; a and b independently represent an integer from 1 to 4; T.sub.1 and T.sub.2 independently represent a spacer portion including a straight chain or branched alkylene or alkylene oxide group having 2 to 20 carbon atoms; and Ar represents a divalent group having at least one aromatic ring selected from a group consisting of aromatic hydrocarbon rings and aromatic heterocycles, the number of Π electrons in the Ar group being 8 or greater.

Heterocyclic liquid crystal compositions that can allow for the adjustment of their refractive indices by the application of an electric field, such as those described by the following formula: ##STR00001##
are disclosed. Also disclosed are selectively dimmable reverse-mode polymer dispersed liquid crystal (PDLC) elements and devices using the aforementioned compositions, which are transparent when no voltage is applied and opaque when a voltage is applied.

Described herein are heterocyclic liquid crystal compositions that can allow for the adjustment of their refractive indices by the application of an electric field. In addition, selectively dimmable reverse-mode polymer dispersed liquid crystal (PDLC) elements and devices using these compositions are also described, which are transparent when no voltage is applied and opaque when a voltage is applied.

Disclosed herein is a light emitting device and method of manufacturing such a device comprised of a series of photopolymerizable, chiral liquid crystalline layers that can be solvent cast on a substrate. The mixture of chiral materials in each successive layer may be blended in such a way that each layer has the same chiral pitch. Further the chiral materials in each layer may also be blended so that the ordinary and extraordinary refractive indices in each layer match the other layers such that the complete assembly of layers will optically function as a single relatively thick layer of chiral liquid crystal. The chiral nematic material in each layer can spontaneously adopt a helical structure with a helical pitch. The light emitting layers of the light emitting device can further comprise electroluminescent material that emits light into the band edge light propagation modes of the photonic crystal.