Formulations for improved electrophoretic display suspensions and related methods
AssigneeCopytele, Inc.
InventorFrederic E. Schubert
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Abstract
The invention provides an electrophoretic suspension comprising a suspension medium including tetrachloroethylene, 5-ethylidene-2-norbornene and an aromatic solvent including either a mixture of phenyl xylyl ethanes or a mixture of mono and di-benzyl toluene. The suspension further comprises a plurality of pigment particles dispersed in the suspension medium; a fluid dye dissolved in the suspension medium for providing a contrast with the pigment particles; and a charge control agent adsorbed on the pigment particles for preventing the pigment particles from agglomerating.
Claims23
An electrophoretic suspension comprising:
- a suspension medium comprising tetrachloroethylene, 5-ethylidene-2-norbornene and an aromatic solvent;
- a plurality of pigment particles dispersed in said suspension medium;
- a fluid dye dissolved in said suspension medium for providing a contrast with said pigment particles;
- and
- a charge control agent adsorbed on said pigment particles for preventing said pigment particles from agglomerating.
A process for making a suspension for an electrophoretic display, comprising the steps of:
- combining tetrachloroethylene with 5-ethylidene-2-norbornene and an aromatic solvent to form a suspension medium;
- adding pigment particles of a first color to said suspension medium;
- adding a charge control agent to said suspension medium to prevent agglomeration of said plurality of pigment particles;
- dissolving a fluid dye of a second color in said suspension medium;
- and
- ball milling said suspension medium to thoroughly disperse said pigment particles therein.
Dependencies are inferred from the claim text.