Patent 8446664 was granted and assigned to E Ink Corporation on May, 2013 by the United States Patent and Trademark Office.
An electrophoretic medium comprises a continuous phase and a discontinuous phase. The discontinuous phase comprises a plurality of droplets, each of which comprises a fluid and at least one charged particle disposed within the fluid and capable of moving through the fluid upon application of an electric field to the electrophoretic medium. The continuous phase surrounds and encapsulates the discontinuous phase and comprising a polymeric binder and a salt, the salt having an anion containing at least one fluorine atom and having a water solubility of at least about 0.25 per cent by weight at 25° C.