Abstract: A pixel of an electrophoretic display is driven from one extreme optical state to a second optical state different from the one extreme optical state by applying to the pixel a first drive pulse of one polarity; and thereafter applying to the pixel a second drive pulse of the opposite polarity, the second drive pulse being effective to drive the pixel to the second optical state.

Abstract: A color filter array is provided in an electro-optic display by ink jet printing a plurality of colored areas (22R, 22G, 22B) on one surface of a layer of electro-optic material (12), an adhesive layer or a protective layer. Alternatively, the ink jet printing may be effected on the same layers in various sub-assemblies used to produce electro-optic displays.

Abstract: A coating of an encapsulated electrophoretic medium is formed on a substrate (106) by dispersing in a fluid (104) a plurality of electrophoretic capsules (102), contacting at least a portion of a substrate (106) with the fluid (104); and applying a potential difference between at least a part of the portion of the substrate (106) contacting the fluid (104) and a counter-electrode (110) in electrical contact with the fluid (104), thereby causing capsules (102) to be deposited upon at least part of the portion of the substrate (106) contacting the fluid (102). Patterned coatings of capsules containing different colors may be deposited in registration with electrodes using multiple capsule deposition steps. Alternatively, patterned coatings of capsules may be formed by applying a fluid form of an electrophoretic medium to a substrate, and applying a temporally varying voltage between an electrode and the substrate. The process may be repeated to allow for deposition of full color displays.

Abstract: A flexible electro-optic display comprises a layer of solid electro-optic material; a backplane comprising at least one electrode arranged to apply an electric field to the layer of electro-optic material; and an adhesive layer disposed between the layer of electro-optic material and the backplane and adhesively securing the layer of electro-optic material to the backplane, the adhesive layer having a storage modulus (G?) of at least about 104 Pascals at 10?3 Hz and 70° C.

Abstract: A first electrophoretic medium comprises an electrically charged particle suspended in a suspending fluid, the particle having a polymeric shell having repeating units derived from at least one monomer the homopolymer of which is incompatible with the suspending fluid. A second, similar electrophoretic medium comprises a suspending fluid, and first and second types of electrically charged particle suspended in the suspending fluid, the two types of particle having differing optical characteristics but both having polymeric shells. The polymeric shells are arranged such that homoaggregation of the two types of particles is thermodynamically favored over heteroaggregation.

Abstract: A first electrophoretic medium comprises an electrically charged particle suspended in a suspending fluid, the particle having a polymeric shell having repeating units derived from at least one monomer the homopolymer of which is incompatible with the suspending fluid. A second, similar electrophoretic medium comprises a suspending fluid, and first and second types of electrically charged particle suspended in the suspending fluid, the two types of particle having differing optical characteristics but both having polymeric shells. The polymeric shells are arranged such that homoaggregation of the two types of particles is thermodynamically favored over heteroaggregation.

Abstract: Various types of edge seals for protecting electro-optic displays against environmental contaminants are described. In one type of seal, the electro-optic layer is sandwiched between a backplane and a protective sheet and a sealing material extends between the backplane and the protective sheet. In other seals, the protective sheet is secured to the backplane or to a second protective sheet adjacent the backplane. The electro-optic layer can also be sealed between two layers of adhesive or between one layer of adhesive and the backplane. Other seals make use of flexible tapes extending around the periphery of the display.

Abstract: A laminate comprising a solid electro-optic medium and an electrically conductive layer is tested by passing it over a pair of electrodes at different potentials, with the electrically conductive layer lying on the opposed side of the electro-optic medium from the electrodes. An article which can be tested by this method, and which is useful in the manufacture of electro-optic displays, comprises a layer of a solid electro-optic medium and a release sheet comprising an electrically conductive layer.

Abstract: The image stability of electrophoretic media, comprising a plurality of particles disposed in a fluid and capable of moving through the fluid upon application of an electric field to the medium, can be improved by including in the fluid either a polystyrene or an aggregating diblock copolymer which forms micelle-like structures in the fluid, the diblock copolymer having a first block soluble in the fluid and a second block not swellable by the fluid. In variable transmission electrophoretic media, haze can be reduced by using as the fluid a mixture of a partially hydrogenated aromatic hydrocarbon and a terpene.

Abstract: An electro-optic display comprises, in order, a backplane comprising a plurality of pixel electrodes; a layer of a solid electro-optic medium; a main adhesive layer; and at least one of a light-transmissive protective layer and a light-transmissive electrically-conductive layer. The electro-optic layer may be in direct contact with the backplane or separated therefrom by a thin auxiliary layer of adhesive. The main adhesive layer may be colored to provide a color filter array. An inverted front plane laminate useful in forming such a display comprises the same layers except that the backplane is replaced by a release sheet. The display combines good low temperature performance and good resolution at higher temperatures.

Abstract: An electro-optic display comprises a backplane; a layer of electro-optic material disposed adjacent the backplane; a protective layer; and a sealing layer of a metal or a ceramic extending between the backplane and the protective layer, and thus sealing the layer of electro-optic material from the outside environment.

Abstract: An electrophoretic display comprises an electrophoretic medium having a plurality of charged particles suspended in a suspending fluid, and two electrodes disposed on opposed sides of the electrophoretic medium. At least one of the electrodes is light-transmissive and forming a viewing surface. The display has a closed optical state in which the charged particles are spread over substantially the entire viewing surface so that light cannot pass through the medium, and an open optical state in which the electrophoretic particles form chains extending between the electrodes so that light can pass through the electrophoretic medium. Insulating layers are disposed between the electrodes and the electrophoretic medium. Similarly electrophoretic displays are provided equipped with color filter arrays or reflectors.

Abstract: Various improvements are provided in gas-based electrophoretic displays, including (a) the use of water getters to remove water from the gas; (b) the use of electron accepting or donating gases; (c) the use of electrophoretic polymer particles having high glass transition temperatures; (d) lateral movement of electrophoretic particles within the display; and (e) the use of variable thickness coatings on electrodes to provide for gray scale.

Abstract: An encapsulation material, intended for use in encapsulated electrophoretic displays, comprises the coacervation product of a polyanionic polymer having a vinyl main chain and a plurality of anionic groups bonded to the main chain, with a cationic or zwitterionic water-soluble polymer capable of forming an immiscible second phase on contact with the polyanionic polymer.

Abstract: A dielectrophoretic display has a substrate having walls defining a cavity, the cavity having a viewing surface and a side wall inclined to the viewing surface. A fluid is contained within the cavity; and a plurality of particles are present in the fluid. There is applied to the substrate an electric field effective to cause dielectrophoretic movement of the particles so that the particles occupy only a minor proportion of the viewing surface.

Abstract: Copper chromite particles can advantageously be used as black particles in electrophoretic media and displays. Preferably, the copper chromite particles are coated with a silica coating and a polymer coating.

Abstract: An electrophoretic display comprises an electrophoretic medium having a plurality of charged particles suspended in a suspending fluid, and two electrodes disposed on opposed sides of the electrophoretic medium. At least one of the electrodes is light-transmissive and forming a viewing surface. The display has a closed optical state in which the charged particles are spread over substantially the entire viewing surface so that light cannot pass through the medium, and an open optical state in which the electrophoretic particles form chains extending between the electrodes so that light can pass through the electrophoretic medium. Insulating layers are disposed between the electrodes and the electrophoretic medium. Similarly electrophoretic displays are provided equipped with color filter arrays or reflectors.

Abstract: An encapsulation material, intended for use in encapsulated electrophoretic displays, comprises the coacervation product of a polyanionic polymer having a vinyl main chain and a plurality of anionic groups bonded to the main chain, with a cationic or zwitterionic water-soluble polymer capable of forming an immiscible second phase on contact with the polyanionic polymer.

Abstract: Various improvements in electrophoretic media and displays intended for use in light modulators are described. These improvements include index matching of the suspending fluid to a continuous phase surrounding the fluid, index matching of a capsule wall to a binder, planarization of a layer containing electrophoretic capsules before application of adhesive thereto, methods for concentrating electrophoretic particles into limited areas of sidewalls of electrophoretic capsules or microcells in the light-transmissive state of the display, and, in the case of light modulators comprising an electrophoretic layer sandwiched between two transparent plates, forming at least one of the plates so as to absorb electromagnetic radiation which adversely affects the electrophoretic layer.

Abstract: The invention provides materials and methods (including driving methods) for reducing the effects of remnant voltages in electro-optic displays.