US Patent 10018828 Electrowetting display device with stable display states

An electrowetting display device comprising a first fluid; a second fluid immiscible with the first fluid; a first support plate having: a surface adjoined by at least one of the first or second fluids, and a first electrode. The device further comprises a second support plate; a second electrode in electrical contact with the second fluid; and a third electrode. The device comprises a protrusion formed as part of at least one of the first support plate or the second support plate. The protrusion has an elongate shape extending from one to the other of the first or second support plates. The protrusion comprises a protrusion surface formed of a material which, without a voltage applied, is less wettable for the first fluid than the surface of the first support plate.