An electrophoretic medium has walls defining a microcavity containing an internal phase. This internal phase comprises electrophoretic particles suspended in a suspending fluid and capable of moving therethrough upon application of an electric field to the electrophoretic medium. The average height of...http://www.google.de/patents/US7848006?utm_source=gb-gplus-sharePatent US7848006 - Electrophoretic displays with controlled amounts of pigment
