Dielectric dispersion for use in electrophoretic image displays comprises differently colored anionic and cationic particles with polymeric tails

摘要

A dielectric dispersion comprises particles (P1) with covalently bound negatively charged groups and particles (P2) with covalently bound positively charged groups in a liquid medium. P1 and P2 have different colors and P1 and/or P2 have covalently bound polymeric tails to prevent coagulation of oppositely charged particles. Independent claims are also included for the following: (1) the production of a dielectric dispersion by dispersing uncharged particles (P3) with covalently bound chargeable groups in a medium (M1), dispersing uncharged particles (P4) with covalently bound chargeable groups in a medium that is the same as or miscible with M1, where P3 and P4 have different colors and P3 and/or P4 have covalently bound polymeric tails to prevent coagulation of oppositely charged particles, and mixing the dispersions to generate opposite charges on P3 and P4 by charge transfer; (2) a pixel comprising a dielectric dispersion as above between two electrodes; and (3) an electrophoretic image display comprising pixels as above.