Patent ID: 7050040

Claim:
A method of improving the contrast ratio of an encapsulated electrophoretic display comprising the steps of: a. providing a two-particle electrophoretic display consisting of at least one first particle of a first color and a first electrical charge and at least one second particle of a second color and a second electrical charge; b. suspending said first particles and said second particles in a suspension medium contained in a matrix of cells each having a viewed region and a non-viewed region; c. applying an AC field to said first particles and to said second particles to vibrate and separate both said first and said second particles; d. applying a DC field having a first polarity to said first particles and to said second particles affects a first color state by causing migration of said first particles toward said viewed region and said second particles towards said non-viewed region, wherein steps c) and d) are applied simultaneously for at least a portion of time; e. changing said DC voltage from a first voltage to a second voltage; f. at least once, changing said DC voltage from said second voltage to a third voltage and finally changing back to said second voltage while affecting same said first color state.