Abstract: The invention relates to an optically biaxial film comprising an anisotropic material with deformed helically twisted structure and locally varying birefringence, to methods and materials for its preparation, to its uses as retardation or compensation film in optical devices like liquid crystal displays, and to compensators and liquid crystal displays comprising such a biaxial film.

Abstract: The invention relates to a polymerised liquid crystal (LC) film comprising at least one photoisomerisable compound and having a pattern of regions with different retardation and/or different orientation of the LC material, to methods of preparing such a film, and to its use as alignment layer, optical retardation film or optical waveguide in liquid crystal displays or other optical or electrooptical components or devices, or for decorative or security applications.

Abstract: The invention relates to new polymerisable mesogenic or liquid crystalline compounds comprising a laterally substituted cinnamate group, to polymerisable mesogenic or liquid crystalline mixtures and anisotropic polymers prepared thereof, and to the use of the new compounds and the mixtures and polymers prepared thereof in optical and electrooptical devices, adhesives, synthetic resins with anisotropic mechanical properties, cosmetics, diagnostics, liquid crystal pigments, decorative and security applications, nonlinear optics, optical information storage, electronic devices like organic field effect transistors (FET or OFET), electroluminescent devices, or as chiral dopants.

Abstract: A liquid crystal display device containing a liquid crystal cell and at least one reflective polarizer or a polarizer combination having at least one reflective polarizer as a means to generate circular polarized light. The reflective polarizer includes an optically active layer of an anisotropic polymer material with a helically twisted planar molecular orientation. The material is oriented so that the axis of the molecular helix extends transversely to the layer, and the pitch of the molecular helix is varied in such a manner that the difference between the maximum pitch and the minimum pitch is at least 100 nm.

Abstract: A liquid crystal display device containing a liquid crystal cell and at least one reflective polarizer or a polarizer combination having at least one reflective polarizer as a means to generate circular polarized light. The reflective polarizer includes an optically active layer of an anisotropic polymer material with a helically twisted planar molecular orientation. The material is oriented so that the axis of the molecular helix extends transversely to the layer, and the pitch of the molecular helix is varied in such a manner that the difference between the maximum pitch and the minimum pitch is at least 100 nm.

Abstract: The invention relates to an electrooptical liquid crystal systemwhich contains a dielectrically positive liquid crystal mixture and a further optically transparent medium between 2 electrodes which are optionally applied to substrate sheets,whose liquid crystal molecules in the switched-off state have an irregular orientation,in which one of the refractive indices of the liquid crystal mixture essentially agrees with the refractive index of the matrix n.sub.M and/or in which the quotient of the mass of the liquid crystal mixture and of the mass of the optically transparent medium is 1.5 or more and,which, independently of the polarization of the incident light, has a reduced transmission in one of the two switch states compared to the other state andwhose liquid crystal mixture contains one or more compounds of the formula I ##STR1## in which Q.sup.1 is ##STR2## are independently of one another trans-1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene and one of A.sup.

Abstract: The invention relates to a liquid-crystalline material in the form of an anisotropic gel consisting of a polymerized liquid-crystalline material and a low-molecular weight liquid-crystalline material, wherein the polymerized material (a) forms a permanently oriented network in the low-molecular liquid-crystalline material (b), characterized in that the low-molecular weight liquid-crystalline material (b) exhibits a cholesteric phase, and to a display cell with such a material.

Abstract: The invention relates to an electrooptical liquid crystal systemwhich between two electrode layers there is contained a liquid crystal mixture and a further optically transparent polymer medium,whose liquid crystal molecules have irregular orientation in the switched-off state,in which one of the refractive indices of the liquid crystal mixture is substantially the same as the refractive index of the medium n.sub.m and/or in which the quotient from the weight of the liquid crystal mixture and the weight of the optically transparent medium is 1.

Abstract: The invention relates to an electrooptical liquid crystal systemwhich contains a dielectrically positive liquid crystal mixture and a further optically transparent medium between 2 electrodes which are optionally applied to substrate sheets,whose liquid crystal molecules in the switched-off state have an irregular orientation,in which one of the refractive indices of the liquid crystal mixture essentially agrees with the refractive index of the matrix n.sub.M and/or in which the quotient of the mass of the liquid crystal mixture and of the mass of the optically transparent medium is 1.5 or more and,which, independently of the polarization of the incident light, has a reduced transmission in one of the two switch states compared to the other state andwhose liquid crystal mixture contains one or more compounds of the formula I ##STR1## in which Q.sup.1 is ##STR2## are independently of one another trans-1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-l,4-phenylene, 3-fluoro-1,4-phenylene and one of A.sup.