Electrophoretic media and processes for the production thereof

An active matrix electro-optic display comprising:

• a layer of electro-optic medium, the electro-optic medium comprising a plurality of charged particles disposed in a liquid and capable of moving therethrough on application of an electric field to the electro-optic medium;
• and
• a plurality of pixel electrodes disposed adjacent the layer of electro-optic medium and arranged to apply an electric field thereto,
• the electro-optic medium exhibiting a voltage threshold and the charged particles having polymeric shells having repeating units derived from at least one monomer the homopolymer of which is incompatible with the suspending fluid,
• the electro-optic medium further comprising a second type of electrically charged particle having at least one optical characteristic differing from that of the other electrically charged particle, the second type of electrically charged particle having a polymeric shell.

An active matrix electro-optic display comprising:

• a layer of electro-optic medium, the electro-optic medium comprising a plurality of charged particles disposed in a fluid and capable of moving therethrough on application of an electric field to the electro-optic medium;
• and
• a plurality of pixel electrodes disposed adjacent the layer of electro-optic medium and arranged to apply an electric field thereto,
• wherein the electro-optic medium exhibits a voltage threshold and comprises:
• a first type of electrically charged particle disposed in the fluid, the first type of particle having a first optical characteristic and a polymeric shell;
• and
• a second type of electrically charged particle disposed in the fluid, the second type of particle having a second optical characteristic differing from the first optical characteristic, and a polymeric shell;
• wherein the polymeric shells are arranged such that homoaggregation of the first and second types of particles is thermodynamically favored over heteroaggregation.