Abstract: A liquid crystal display cell comprising a chiral ferroelectric smectic liquid crystal layer whose helix structure is influenced by the action of an electric field such that its optical anisotropy alters; a pair of transparent plates between which the liquid crystal is disposed and which have a surface structure for aligning the molecule of the liquid crystal and are provided with electrodes to produce an electric field therein; and one polariser each before and after the liquid crystal: such ratio d/p of the thickness d of the liquid crystal layer to the pitch height p of the helical twisting is greater than 5, the smectic tilt angle .theta..sub.o is being between 22.5.degree. and 50.degree. and the product d.multidot..theta..sub.o.sup.2 .multidot..DELTA.n.multidot.l/.lambda. (phase factor) of the thickness d, the square of the tilt angle .theta..sub.o, the value of the birefringence .DELTA.n and the reciprocal of the wavelength .lambda. of light bedding is greater than 0.45 .mu.m.

Abstract: Optically active compounds of the formula ##STR1## wherein rings A, B and C each independently are unsubstituted or each are 1,4-phenylene substituted with at least one of halogen-, cyano-, methyl- or methoxy in which optionally 1 CH group or 2 CH groups is/are replaced by nitrogen; R.sup.1 is a radical of an optically active terpene alcohol after cleavage of the hydroxy group or a group --(CH.sub.2).sub.m --C*HX.sup.1 --R.sup.3 ; R.sup.2 is a radical of an optically active terpene alcohol after cleavage of the hydroxy group or a group --(CH.sub.2).sub.n --C*HX.sup.2 --R.sup.4 ; m and n each independently stand for the number 0 or 1: C* denotes a chiral carbon atom; X.sup.1 and X.sup.2 each independently are fluorine, chlorine, cyano, methyl or methoxy; R.sup.3 and R.sup.4 each independently denote a group R, phenyl or phenyl substituted with R, with the proviso that R.sup.3 is different from X.sup.1 and R.sup.4 is different from X.sup.

Abstract: An oriented photopolymer is a polymer where photomodification is initiated by irradiation with plane-polarized light and where the molecular configuration has a preferred orientation as a result of linear polarization. These polymers have optically anisotropic and other novel properties.

Abstract: The polarizer comprises a layer of cholesteric liquid crystal with Grandjean structure disposed in the path of the light and in which the light in a given wavelength range is reflected with selective and circular polarization or is transmitted with reversed direction of rotation, and a mirror which reversed the direction of rotation of the circular-polarized light. The component reflected by the mirror is also transmitted. If the liquid crystal layer is concentric with the source of natural light and the mirror is spherical, the result is a source of circular polarized light. A projection system is obtained by a combination of two of the aforementioned polarizers, one serving as a polarizer and one as an analyzer, and an interposed liquid crystal display cell for modulating the intensity of the polarized light.

Abstract: Compounds of the formula ##STR1## wherein R.sup.1 is alkyl or trans-4-alkylcyclohexyl andR.sup.2 is alkyl, alkoxy or trans-4-alkylcyclohexyl their preparation, liquid crystalline mixtures containing these compounds and their use for electro-optical purposes.

Abstract: The polarizer comprises a layer of cholesteric liquid crystal with Grandjean structure disposed in the path of the light and in which the light in a given wavelength range is reflected with selective and circular polarization or is transmitted with reversed direction of rotation, and a mirror which reversed the direction of rotation of the circular- polarized light. The component reflected by the mirror is also transmitted. If the liquid crystal layer is concentric with the source of natural light and the mirror is spherical, the result is a source of circular polarized light. A projection system is obtained by a combination of two of the aforementioned polarizers, one serving as a polarizer and one as an analyzer, and an interposed liquid crystal display cell for modulating the intensity of the polarized light.