US Patent 7430073 Electrophoretic display device and method of displaying image

An electrophoretic display device includes a display layer comprised of a multiplicity of individual reservoirs containing a display medium over a conductive substrate, wherein the display medium comprises one or more set of colored particles dispersed in a dielectric fluid, the display medium having an electrical conductivity of about 1031 11 to about 10−15 S/m. The device further includes either or both a color filter layer over the display layer, wherein the color filter layer comprises each of a red tinted transparent portion, a blue tinted transparent portion and a green tinted transparent portion, and a dark colored light absorptive backplane under the display layer.