A liquid crystal mixture for electro-optical displays without polarising cover discs consists essentially of a nematic liquid crystal mass with positive or negative dielectric anisotropy as host phase, an optically active additive to effect cholesteric orientation of the host phase and, embedded as a guest phase in the host phase, at least one pleochroic anthraquinone dye of the formula (1) IMAGE where R1, R2, R3 and R4 are each hydrogen, hydroxyl, amino or nitro, m is 1 or 2, n is zero, 1 or 2, R5 and R6 are identical or different and each is hydrogen or a radical of the formula (1a) or (1b) IMAGE where a is an integer from 1 to 10, b is zero or an integer from 1 to 6, and X is oxygen, sulphur, a single bond or oxycarbonyl, and R7 is hydrogen, an alkyl or alkoxy group of 1 to 12 carbon atoms or a phenyl or phenoxy group.
展开▼
