Peak reflectance and color gamut of superimposed left- and right-handed cholesteric liquid crystals

Coatings of cholesteric liquid crystals (CLCs) have properties of narrowband optical filters. It has been proposed and tested experimentally that superimposed coatings of left- and right-handed CLCs double the peak reflectance from 0.5 to 1.0. In an alternate method a halfwave plate inserted between two coatings of leftor right-handed CLCs accomplishes the same result. As the spectra of such superimposed coatings resemble those of optimum colors, the color gamut obtained with such liquid crystal coatings approaches that of optimum colors.