US Patent 8018640 Particles for use in electrophoretic displays

A particle for use in an electrophoretic display comprises a light-scattering inorganic core and a light-transmissive colored shell of an organic pigment. In preferred particles, the core is titania and the shell is formed of particles having an average particle size less than 700 nm. The particles are produced by treating a light-scattering inorganic pigment with a polymer which adsorbs on both the inorganic pigment and an organic pigment; and adding the organic pigment and allowing the organic pigment to mix with the polymer-coated inorganic pigment.