US Patent 7307779 Transmissive E-paper display

In accordance with the invention, there are systems for electronic paper, apparatus for electrophoretic display, and methods of making an electrophoretic display. The system for electronic paper can comprise a light transmissive electret substrate comprising a gradient of charges and a plurality of capsules disposed in the light transmissive electret substrate, wherein each of the plurality of capsules can comprise a plurality of charged pigments with a polarity opposite to that of the charges in the light transmissive electret substrate.