A method for preparing a switching element which is operable in and electrically switchable between an optically clear state and a scattering state, wherein one or more polymerisable mesogenic compounds provided in a layer containing a liquid-crystalline medium which comprises one or more mesogenic compounds, one or more chiral compounds and the one or more polymerisable mesogenic compounds are subjected to polymerisation in the presence of a direct current (DC) electric field in the layer. Also, a switching element obtained or respectively obtainable by carrying out the method and to the use of the switching element in a window.

The present invention relates to a liquid-crystalline medium (LC medium), to the use thereof for electro-optical purposes, and to LC displays containing this medium.

The present invention relates to an assembly of switching layers for dimming and scattering of light and to window elements comprising the arrangement of switching layers.

The present invention relates to benzotriazole derivatives selected from the group of compounds of formulae Ia, Ib and Ic as defined in claim 1, to mesogenic media comprising the compounds of formulae Ia, Ib and Ic, and to the use of these compounds and mesogenic media in optical, electronic and electro-optical applications, in particular in devices for regulating the passage of energy from an outside space into an inside space, for example in windows.

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.

The present invention relates to liquid-crystalline media comprising one or more mesogenic compounds, one or more chiral compounds, and one or more polymerisable mesogenic compounds, wherein the media exhibit a pitch of 0.55 μm or more and a clearing point of 80° C. or more and wherein the one or more polymerisable mesogenic compounds are contained in an amount, based on the overall contents of the media, of 5% by weight or less. The present invention further relates to modulation materials obtainable from the media and to switching layers and window elements containing the materials.

A smectic A composition with the positive dielectric anisotropy exhibiting a monolayer smectic A structure (SmA.sub.1), which shows a phase transition from a smectic A phase to an isotropic phase (SmA-Iso) or a phase transition from a smectic A phase through a nematic phase to an isotropic phase (SmA-N-Iso) and includes at least two fluorinated compounds selected from the families of fluorinated derivatives of biphenyls and terphenyls expressed by the general formulae 1-12.

For ensuring of the high level of the conductivity the composition is doped with the ionic amidynium salts and/or the ionic potassium complexes of the crown ethers wherein the charge on the cation is delocalized. Such a structure of the ionic compound ensures the better solubility in the liquid crystalline fluorinated composition in comparison to that observed for quaternary ammonium salts.

For writing of the information the dynamic scattering effect (DS) was used, where the transition from a opaque (milky) state to a clear (transparent) state or reversal process is obtained by the change of the frequency of a driving alternating electric field.

The modification of the properties of the smectic A composition by adding of further components such as fluorinated four ring liquid crystal compounds or pyrimidine compounds or cyanocompounds is described.

The present invention relates to liquid-crystalline media comprising one or more mesogenic compounds of formula I as set forth hereinafter, wherein the one or more compounds of formula I are contained in the medium in an amount, based on the overall contents of the medium, of at least 15% by weight. The present invention further relates to a switching layer, a switching element and a window element containing the liquid-crystalline medium.

The invention relates to a liquid-crystalline medium comprising one or more compounds of the formula CC

##STR00001##

in which the groups occurring have the meanings indicated in Claim 1, and to the use of the liquid-crystalline medium for electro-optical purposes, in particular in liquid-crystal light valves for lighting devices for vehicles, and to liquid-crystal light valves which comprise this medium and lighting devices for vehicles which contain liquid-crystal light valves of this type.

The present invention relates to liquid crystalline media comprising one or more naphthothiadiazol derivatives of formula I, ##STR00001##
in which R.sup.11, R.sup.12, A.sup.11, A.sup.12, A.sup.21, A.sup.22, Z.sup.11, Z.sup.12, Z.sup.21, Z.sup.22, W, X.sup.11, X.sup.12, L, r, s and t have the meanings indicated in claim 1, to the use of such liquid crystal media for optical, electro-optical and electronic purposes, in particular in devices for regulating the passage of energy from an outside space into an inside space, for example in windows.