Non polarizer guest-host mode based on dyes with negative dichroism

A new configuration of non polarizer "guest-host" mode, based on the liquid crystal mixture doped with black mixtures of dichroic dyes with negative dichroism, is proposed and demonstrated for the first time. Both transmissive and reflective variants are possible with either monochromatic or black/white switching. It is shown that the contrast ratio is not limited in this case. A contrast ratio of more than 5 : 1 for normal incidence and a contrast ratio of more than 3 : 1 for wide viewing angles are demonstrated in an experiment and the electrooptic response is found to be almost independent of the azimuthal angle of light incidence.