US Patent 9249356 Liquid crystal dye mixture

A guest-host liquid crystal dye mixture comprising a calamatic, thermotropic liquid crystal as host and a dichroic fluorescent dye as guest, characterized in that the dichroic fluorescent dye is a multichromophoric dye containing at least a group with the general formula Ry-X1—C1, wherein Ry is a chromophore from the rylene family, C1 is a second chromophore and X1 is a spacer that interrupts the conjugation between Ry and C1, the spacer X1 is selected such that it introduces rigidity against bending or folding over an axis perpendicular to the length of the molecule.