Patent ID: 7767112

Claim:
A method for inducing or enhancing the threshold voltage of an electrophoretic display, which method comprises adding a threshold promoter into an electrophoretic fluid which comprises charged pigment particles or pigment-containing microparticles dispersed in a fluorinated dielectric solvent or solvent mixture, wherein said threshold promoter is represented by one of the following formulas: R-[Q-L-X-Q′-(L′-Y) m ] q (T-2) R-[Q-L-(X-Q′-L′-Y) m ] q (T-3) [(X) m -L-Q] q -R-[Q′-L′-(Y) m′ ] q′ (T-4) wherein: m and m′ are independently natural numbers which are ≧1; q and q′ are independently natural numbers which are ≧1; R is a halogenated group, a halogenated polymeric chain, or a halogenated oligomeric chain; Q and L or Q′ and L′ together forming a linking chain; and X and Y are independently functional groups capable of forming hydrogen bonding, acid-base interaction, donor-acceptor interaction, metal-ligand interaction or Coulombic interaction.