ABSTRACT
The dichroic dyes and liquid crystalline materials possessing the properties required for practical applications are commercially available from quite a number of companies. The Japanese firms, Mitsui Toatsu Dyes and Dichstal, offer dichroic dye of the L-type for guest-host liquid crystal displays (LCDs) of both positive and negative types, as well as for the microcapsulated ones. It should be noted that introduction of anthraquinone dyes in Liquid crystal materials (LCM) leads to better viscosities than in the host. The order parameters of the anthraquinone dyes in E201 at 20°C are about 10% lower than those of the biphenyl host, E63. E208 represents a wide-range, low-birefringent mixture containing cyclohexylcyclohexane compounds, and is recommended for applications in LCDs based on the phase change effect. Hoffmann-La Roche advertises a wide range of LCM with negative contrast providing colorless or weakly colored symbols on a colored background.
