Patent ID: 7038655

Claim:
An electrophoretic display having a viewing surface, the display comprising: an image pixel comprising: a first plurality of particles having a first mobility, μ 1 (V); and a second plurality of particles having a second mobility, μ 2 (V), at least one of the first and second mobilities varying with the addressing voltage V applied to the pixel such that at a first addressing voltage V 1 : μ 1 ( V 1 )>μ 2 ( V 1 ) whereas at a second addressing voltage V 2 : μ 2 ( V 2 )>μ 1 ( V 2 ) whereby the image pixel can produce a first optical state determined by a motion of the first plurality of particles by application of the first addressing voltage V 1 and a second optical state determined by a motion of the second plurality of particles by application of the second addressing voltage V 2 .