A multi-color electrophoretic medium contains first, second and third species of particles, the particles having substantially non-overlapping electrophoretic mobilities and bring of three different colors. The particles are dispersed in a fluid having a fourth color. A method for driving such a display...http://www.google.co.uk/patents/US8040594?utm_source=gb-gplus-sharePatent US8040594 - Multi-color electrophoretic displays
