Dyestuffs and Liquid Crystals

Abstract

This review paper surveys the various modes whereby electro-optical displays using liquid crystals may be operated, and concentrates attention upon those displays in which dichroic dyes can be incorporated advantageously in the liquid crystal. The problems of finding dyes with suitable order parameters, solubilities, and photochemical stabilities are discussed in the context of extensive experimental work on azo dyes and anthraquinone dyes. Although very good displays can now be made using the best of such dyes, further research is needed before completely satisfactory dyes covering the yellow, the red and the blue colour ranges can be considered to be available.