Viologen-based electrochromic light scattering display

In conventional viologen-based electrochromic displays, contrast changes are achieved by modulating light using the optical absorbance of the electrodeposited film. A display technique is described which uses instead the light scattering properties of the same film to produce intensity variations. Under practical conditions, contrast ratios of 60:1 can be achieved by electrodepositing 1 mC cm-2 of the n-heptyl viologen cation radical with a 1-ms current pulse. The display also has memory and is compatible with integrated drive schemes.