The invention relates to mesogenic media comprising one or more bimesogenic compounds, one or more nematogenic compound, one or more chiral compound and a compound of formula I,
R.sup.11-A.sup.11-(Z.sup.12-A.sup.12).sub.m-AGI
in which, the parameter A.sup.11, A.sup.12, Z.sup.12 and R.sup.11 have one of the meanings as given in claim 1, and to the use of these mesogenic media in liquid crystal devices and in particular in flexoelectric liquid crystal devices, as well as to liquid crystal devices comprising a liquid crystal medium according to the present invention.

The present invention relates to liquid crystal media comprising polymerizable mesogenic compounds with a bent shape, and to electro-optical displays comprising these media as light modulation media. In particular the electro-optical displays according to the present invention are displays, which are operated at a temperature, at which the liquid crystal modulation media are in an optically isotropic phase, preferably in a blue phase.

Disclosed is a polymerizable compound having a structural formula as represented by the following formula I:

##STR00001##

The polymerizable compound disclosed in the present invention has a plurality of ring systems, and the entire molecular structure thereof is curved and twisted. The present invention further discloses a liquid crystal medium comprising the polymerizable compound, the polymerizable compound provided by the present invention has an appropriate polymerization rate in the liquid crystal medium, and the liquid crystal medium can be well applied to a PS-(polymer stabilized)- or PSA-(polymer stabilized alignment)-type liquid crystal display device. Further disclosed is a liquid crystal display device prepared from the liquid crystal medium.

The invention relates to a method of preparing a polymer film and to the use of such polymer film as in liquid crystal displays (LCDs) or other optical or electrooptical devices, for decorative or security applications, as alignment layer or optical retardation film.

The invention relates to chiral compounds of formula I

##STR00001##

wherein the parameters have the meaning given in claim 1, to liquid crystal mixtures comprising at least one chiral compound of formula I, to chiral linear or crosslinked liquid crystal polymers obtainable by polymerizing a polymerizable mixture comprising at least one chiral compound of formula I, to the use of chiral compound of formula I and mixtures and polymers obtained thereof in liquid crystal displays, active and passive optical elements, adhesives, synthetic resins with anisotropic mechanical properties, cosmetic and pharmaceutical compositions, diagnostics, liquid crystal pigments, for decorative and security applications, nonlinear optics, optical information storage or as chiral dopants, and to a liquid crystal display comprising a mixture comprising at least one chiral compound of formula I.

Provided are a cholesteric liquid crystal composition, and a liquid crystal display panel including the composition, and their preparation methods. The cholesteric liquid crystal composition contains a block copolymer and a cholesteric liquid crystal, wherein the block copolymer has a block A including a chiral group M.sub.1 and a block B including a chiral group M.sub.2, and the cholesteric liquid crystal has at least two different pitches. The display panel includes an array substrate and a counter substrate placed by cell assembly, and a liquid crystal layer disposed between the array substrate and the counter substrate, wherein the liquid crystal layer comprises the cholesteric liquid crystal composition. The liquid crystal layer in the planar texture is capable of reflecting light of at least two wavelengths in the visible light region.

The liquid crystal display element uses a liquid crystal composition which has a negative value of dielectric anisotropy () and is designed to improve light transmittance adjusting an elastic constant, and a liquid crystal display including the liquid crystal display element. The liquid crystal display element uses a liquid crystal composition having a dielectric anistropy () of less than 1.5, in which a value of of the liquid crystal composition is 0.3 or less, and the value of is obtained from Equation (2) using measured values of a splay elastic constant (K.sub.11) and a bend elastic constant (K.sub.33) of the liquid crystal composition and a twist elastic constant (K.sub.22) value obtained from Equation (1) using measured values of a threshold voltage (Vth), a bend elastic constant (K.sub.33), vacuum permittivity (.sub.0), a cell gap (d), and a helical pitch (P.sub.0).

[00001]$\begin{array}{cc}{V}_{\mathrm{th}}=.Math.\sqrt{\left\{1-4.Math.{\left(\frac{K_{22}}{K_{33}}\right)}^2.Math.{\left(\frac{d}{P_0}\right)}^2\right\}.Math.\frac{K_{33}}{.Math.{\mathrm{.Math.}}_0.Math.\mathrm{.Math.}.Math.}}& \left(1\right)\\ =\frac{K_{22}}{K_{11}+K_{33}}& \left(2\right)\end{array}$

The invention relates to mesogenic media comprising a first component, component A, consisting of bimesogenic compounds selected from the group of compounds of formulae A-I to A-III ##STR00001## a second component, component B, consisting of nematogenic compounds, preferably selected from the group of compounds of formulae B-I to B-III ##STR00002## and a third component, component C, consisting of one or more chiral molecules, wherein the parameters have the meaning given in claim 1, to the use of mesogenic media in flexoelectric liquid crystal devices and to those devices comprising a liquid crystal medium according to the present invention.

The present invention relates to a liquid crystal composition. The liquid crystal composition comprises four compounds having different structural formulas and a chiral compound. The four compounds having different structural formulas are at least one compound selected from general formula I, at least one compound selected from general formula II, at least one compound selected from general formula III, and at least one compound selected from general formula IV, respectively. By optimizing the content of each component in the liquid crystal composition, a clearing point is improved while reducing a phase transition point of the N-TB. Also provided is a bistable liquid crystal dimming device prepared by applying the liquid crystal composition, which widens the working temperature range of the bistable liquid crystal dimming device, and improves the value of the bistable liquid crystal dimming device in practical applications.

The present invention provides the following: a photo alignment method-use liquid crystal aligning agent used to obtain a photo alignment method-use liquid crystal alignment film that does not cause bright spots even when negative liquid crystals are used, and that is capable of achieving good after-image characteristics; a liquid crystal alignment film obtained from the liquid crystal aligning agent; and a liquid crystal display element provided with the liquid crystal aligning agent. Provided is the liquid crystal aligning agent which contains a polyimide or polyimide precursor obtained from a reaction between: a tetracarboxylic acid dianhydride represented by formula (1) (in the formula, X.sup.1 is as set forth in the present specification) or a derivative thereof; and a diamine component that contains a diamine represented by formula (2) (in the formula, R.sup.1, Z.sup.1 and n are as set forth in the present specification).