Patent ID: 6819471
Filing Date: 2004-11-16
Classification: G02F

Abstract:
An image display device comprising:(a) a reflective sheet having a prismatic inward surface and an opposed outward surface; (b) an electrophoretic medium contacting the prismatic surface; (c) a plurality of particles suspended in the electrophoretic medium; and (d) means for applying a voltage across the electrophoretic medium to selectively move the particles closely adjacent the prismatic surface to frustrate total internal reflection at the prismatic surface of light rays passing through the reflective sheet, the electrophoretic medium having an index of refraction sufficiently smaller than the index of refraction of the reflective sheet that most of the light passing through the reflective sheet undergoes total internal reflection at the prismatic surface when the particles are not closely adjacent the prismatic surface, wherein the means for applying a voltage comprises a first electrode substantially conforming to the shape of the prismatic surface and a second electrode substantially conforming to the shape of the first electrode such that the gap between the first and second electrodes is of substantially constant width.