US Patent 7411719 Electrophoretic medium and process for the production thereof

A two-phase electrophoretic medium comprises a continuous phase and a discontinuous phase. The discontinuous phase comprises a plurality of droplets, each of which comprises a suspending fluid and at least one particle disposed within the suspending 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. To reduce the humidity sensitivity of the medium, a non-ionizable or crystalline polymer may be used as the continuous phase.