Reflective Bistable Cholesteric/Polymer Dispersion Display with a Black Polypyrrole Electrode Cast from the Solution

A reflective mode bistable cholesteric/polymer dispersion(CPD) display is proposed in which both the electrode and the light-absorbing layer of the conventional display were substituted with a single polypyrrole(PPy) layer spin-cast from the chloroform solution. Utilization of the black conductive PPy film coated on the inner surface of the rear glass plate not only provided a convenient and economic method of fabricating CPD displays but also improved the contrast ratio by about 20%. By incorporating 20% of polymer into the chiral nematic mixture, the bistabilily and the viewing angle of the display were remarkably enhanced while the reflectance decreased from 89 to 29%.