Dual particle electrophoretic display and method of manufacturing same

An electrophoretic display device, comprising:

• a back substrate comprising:
• a plurality of second walls extending from said back substrate;
• a substrate, being selected from the group of transparent and opaque materials, positioned substantially opposite from said back substrate forming a substantially hollow container between said back substrate and said substrate, said container being sealed about its perimeter, said substrate comprising:
• a plurality of cathode electrodes supported by said substrate forming a plurality of electronically and selectively addressable pixels;
• a plurality of separation walk extending from said substrate, said separation walls interposed between corresponding cathode electrodes and having a top surface substantially parallel to said substrate;
• said plurality of second walls disposed substantially opposite from corresponding ones of said plurality of separation walls, said second walls having a lower edge, wherein a gap is formed between the lower edge of said plurality of second walls and the top surface of corresponding ones of said plurality of separation walls, said separation walls forming cells;
• a plurality of pigment particles in each of said cells, the pigment particles in each of said cells comprised of light particles and dark particles;
• a substantially clear, substantially particle free, suspension fluid disposed in said container, said suspension fluid being substantially uniformly distributed through said container through said gap, said gap being sized to be less than a size of said light particles and said dark particles within a corresponding cell;
• and
• means for applying a voltage to each of said plurality of cathode electrodes for a selected period of time to achieve a desired level of color, wherein said selected period of time is measured from an end of a display frame.

A display comprising:

• a first substrate, including:
• a TFT layer including a plurality of Thin Film Transistors (TFT) arranged in an array of rows and columns;
• a plurality of first walls extending substantially perpendicular from said first substrate, said plurality of first walls having a top surface substantially parallel to said first substrate, said plurality of first walls creating a plurality of cells corresponding to said array of TFTs;
• an electrically conductive element within each of said cells in electrical contact with a corresponding TFT, said first walls and said electrically conductive element being electrically isolated;
• an insulating layer deposited on said first substrate;
• a second substrate, separated from the first substrate by a known distance to form a cavity between the first substrate and said second substrate,
• a plurality of second walls extending from said second substrate, said plurality of second walls disposed substantially opposite from corresponding ones of said plurality of first walls, said second walls having a lower edge substantially parallel to said second substrates wherein a gap is formed in between said lower edge of said plurality of seconds walls and the top surface of corresponding ones of said plurality of first walls;
• a clear, substantially particle free, suspension fluid contained within said cavity, said suspension fluid being substantially uniformly distributed throughout said cavity by being in fluid communication with each of the cells through said gap;
• a first set and a second set of electrically charged particles contained within each of said cells, said first set of electrically charged particles having a different electrical charge that the second set, said gap being sized to contain said first set and second set of electrically charged particles within corresponding cells;
• and
• means for applying a voltage to selected ones of the TFTs in the TFT array for as selected period of time to achieve a desired level of color, wherein said selected period of time is measured from an end of a display frame.