Abstract: A method of making polymer-coated pigment particles, involving the steps of providing a plurality of pigment particles, each of which has an outer surface coated with a layer of material that operates as a nucleus for initiating polymerization on the outer surface of each of the pigment particles. The pigment particles are mixed with a reaction mixture containing a solvent and a monomer material, wherein the layer of material coating each of the pigment particles causes the monomer material to polymerize on the outer surface of substantially each of the pigment particles to form a polymer coating thereon.

Abstract: A dielectric dispersion for use in an electrophoretic display includes a dielectric fluid, a first plurality of particles of a first color having a surface charge of a selected polarity dispersed within the dielectric fluid and a second plurality of particles of a second color having a surface charge of opposite polarity to that of the first plurality and a steric repulsion thereto preventing coagulation of the first and second pluralities. In one embodiment, the first and second plurality of particles are each formed by separate two stage dispersion polymerization reactions. Each set of particles is formed with unique secondary and functional monomers. Corresponding charge control agents are added to the dispersion to establish opposite polarities on the respective particles.

Abstract: Initiator-treated pigment particles for use in making polymer coated pigment particles, are made up of a plurality of pigment particles. Each of the pigment particles has an outer surface that is covered with a coating of initiator material. The initiator material operates as a nucleus for initiating polymerization on the surface of the particle. The initiator-treated pigment particles are made by providing a plurality of pigment particles and applying a coating of initiator material to the outer surface of each pigment particle.

Abstract: A method of making polymer-coated pigment particles, involving the steps of providing a plurality of pigment particles, each of which has an outer surface coated with a layer of material that operates as a nucleus for initiating polymerization on the outer surface of each of the pigment particles. The pigment particles are mixed with a reaction mixture containing a solvent and a monomer material, wherein the layer of material coating each of the pigment particles causes the monomer material to polymerize on the outer surface of substantially each of the pigment particles to form a polymer coating thereon.

Abstract: Properly-coated pigment particles for use in an electrophoretic display include pigment particles having a pre-determined density and application of a polymeric coating to the pigment particles, wherein the coating comprises a near fluoropolymer, and wherein the density of the fluoropolymer is substantially the same as the density of the pigment particles. When a polymeric coating is applied having a density that is substantially the same as the density of the pigment particles, even though the particles comprise a distribution of particle sizes, the density of the pigment particles is not significantly altered. In a preferred embodiment, the pigment particle comprises a diarylide yellow pigment, having a density of 1.43 g/ml, coated with a polymer made from the monomer 2,3,4,5,6-Pentafluorostyrene, having a density of 1.41 g/ml.

Abstract: A process for forming dielectric particles includes admixing a vinyl halide monomer and a crosslinker in a liquid dispersion medium to form a first mixture. A second mixture of an initiator and a stabilizer is prepared and added to the first mixture to form a third mixture in which the monomer polymerizes to form white crystalline polymer particles which are sonified for uniformity. The particles may be stained by exposure to a dehydrohalegenation reagent and dispersed in an electrophoretic fluid for use in an electrophoretic display.

Abstract: A dielectric suspension for use in an electrophoretic image display, electrostatic printing or the like, comprising a suspension medium including a dense fluorinated solvent and a less dense hydrocarbon solvent, 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.

Abstract: A process for forming dielectric particles includes admixing a vinyl halide monomer and a crosslinker in a liquid dispersion medium to form a first mixture. A second mixture of an initiator and a stabilizer is prepared and added to the first mixture to form a third mixture in which the monomer polymerizes to form white crystalline polymer particles which are sonified for uniformity. The particles may be stained by exposure to a dehydrohalegenation reagent and dispersed in an electrophoretic fluid for use in an electrophoretic display.

Abstract: An electrophoretic suspension prepared in accordance with the present invention comprises a dielectric fluid having suspended therein a plurality of pigment particles movable between the electrodes of an EPID device in response to an electric potential applied thereto and an effective amount of at least one additive for chemically absorbing at least one gas in the fluid. To absorb hydrogen gas in the dielectric fluid, a hydrogen absorbing additive is dispersed therein. The molecule of the hydrogen absorbing additive has an aromatic C/H ratio of 1/0.8 or less, and preferably between 1/0.67 and 1/0.75. To absorb chlorine gas in the dielectric fluid, an effective amount of an chlorine gas absorbing compound is also preferably added thereto. The chlorine gas absorbing additive comprises a molecule having at least one double bond and may be a sterically strained alkene such 5-ethylidene-2-norbornene.

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.

Abstract: The invention provides a working fluid for an electrophoretic image display device including a dispersion of finely divided diarylide yellow pigment particles each having a charge of a given polarity and acidic hydrogen surface sites in a suspension medium. Each of the pigment particles are transportable within the suspension medium, under the influence of an electric field, toward or away from at least one transparent plate. Adsorbed on the surface of each pigment particle is a thin layer of a charge control agent having a polyisobutylene chain and a basic anchoring group which reacts with the acidic surface sites to form charge pairs therewith. The polyisobutylene chains extend from the pigment surfaces on which the charge control agent is adsorbed, thereby providing a steric barrier between pigments and preventing agglomeration. The specific gravity of the suspension medium is matched with that of the pigment particles by combining effective amounts of secondary butyl benzene and tetrachloroethylene.

Abstract: A process for forming dielectric particles includes admixing a vinyl halide monomer and a crosslinker in a liquid dispersion medium to form a first mixture. A second mixture of an initiator and a stabilizer is prepared and added to the first mixture to form a third mixture in which the monomer polymerizes to form white crystalline polymer particles which are sonified for uniformity. The particles may be stained by exposure to a dehydrohalegenation reagent and dispersed in an electrophoretic fluid for use in an electrophoretic display.

Abstract: A method of manufacturing an improved an electrophoretic display having a cathode/grid/local anode matrix and a remote anode includes forming the local anode lines in the same plane as the grid lines from the same material and in the same fabricating step. The local anode lines are insulated from the grid lines and are interleaved therewith, each being formed on a common layer of photoresist. It is preferred that each grid line be associated with one local anode line, that the grid lines have tines and that the local anode lines be disposed between the tines.

Abstract: An improvement to an electrophoretic display having a cathode/grid/local anode matrix and a remote anode and to the method for making the display includes forming the local anode lines in the same plane as the grid lines from the same material and in the same fabricating step. The local anode lines are insulated from the grid lines and are interleaved therewith, each being formed on a common layer of photoresist. It is preferred that each grid line be associated with one local anode line, that the grid lines have tines and that the local anode lines be disposed between the tines.

Abstract: There is disclosed methods for fabricating electrophoretic displays. Essentially the methods employ selective materials such as different metals which are capable of being etched by different etchants. In this manner, a laminate is provided to form a grid matrix which is insulated from a cathode matrix which grid matrix is also insulated from a second anode matrix. The entire display utilizes a local or second anode and a remote anode to further control pigment particle migration. The display is fabricated by two methods both of which employ selective etching of the parallel line type of display electrodes which constitute a cathode, a grid and a local anode.

Abstract: There is disclosed methods for fabricating electrophoretic displays. Essentially the methods employ selective materials such as different metals which are capable of being etched by different etchants. In this manner, a laminate is provided to form a grid matrix which is insulated from a cathode matrix which grid matrix is also insulated from a second anode matrix. The entire display utilizes a local or second anode and a remote anode to further control pigment particle migration. The display is fabricated by two methods both of which employ selective etching of the parallel line type of display electrodes which constitute a cathode, a grid and a local anode.

Abstract: There is disclosed a method to enable one to deposit a thin layer of chrome to a thicker layer of an organic polymer. The surface of the organic polymer has a thin layer of silicon dioxide deposited thereon and then a thicker layer of chrome is sputtered onto said layer of silicon dioxide. This enables one to pattern and to wire bond to the chrome layer while avoiding stress cracks in the chrome as provided by prior art techniques.

Abstract: There is disclosed a method which minimizes bubble growth during electrophoretic cell operation. The method involves exposing the electrophoretic suspension to an ultrasonic probe at a given frequency and amplitude and for a suitable time period just prior to pouring the suspension into the electrophoretic display. Exposure to the ultrasonic probe minimizes bubble growth during actual cell operation as the probe operates to drive out a significant amount of gas contained in the suspension while further affecting the pigment particle characteristics.