Controlling engulfing and sequestering magnetic pads

#1. Field of Invention

#The invention relates to the field of visual displays. More particularly, the invention relates to the production of balls used in a gyricon or twisting ball visual display and to the production of gyricon balls having sequestered magnetic pads.

#2. Description of Related Art

#The exemplary embodiments of the invention will be described in detail, with reference to the following figures in which:

#FIG. 1 shows a cross-section of one exemplary embodiment of an electric paper of this invention;

#FIG. 2 shows in greater detail one exemplary embodiment of the gyricon substrate of FIG. 1; and

#The exemplary embodiments of the systems and methods of this invention are directed to addressing gyricon displays in which magnetic materials are added to the composition of the gyricon balls, and magnetic fields are used to augment the usual electrical addressing fields.

#FIG. 1 shows a cross-sectional view of one exemplary embodiment of a sheet 100 of electric paper according to the invention. Specifically, as shown in FIG. 1, a conductive base substrate 130 forms the base substrate of the sheet 100 of electric paper. A gyricon substrate 120 is formed over the conductive base substrate 130. The gyricon substrate 120 includes gyricon balls 200 disposed within the substrate. Each gyricon ball 200 has two distinct hemispheres 220 and 230, one black and the other white, and each hemisphere 220 and 230 has a distinct electrical characteristic, e.g., a zeta potential with respect to a dielectric fluid, so that the gyricon balls 200 are electrically as well as optically anisotropic.

#The gyricon balls 200 are embedded in a sheet of optically transparent material, such as an elastomer layer, that makes up the gyricon substrate 120. The gyricon substrate 120 also contains a multiplicity of spheroidal cavities 122 and is permeated by a transparent dielectric fluid, such as a plasticizer. The fluid-filled spheroidal cavities 122 accommodate the gyricon balls 200. In particular, there is one gyricon ball 200 per cavity 122 in the gyricon substrate 120. The spheroidal cavities prevent the gyricon balls 200 from migrating within the gyricon substrate 120. Each gyricon ball 200 can be selectively rotated within in its respective fluid-filled cavity 122 by applying an electric field to present either the black hemisphere 230 or the white hemisphere 220 to an observer viewing the surface of the sheet 100. Thus, applying an electrical field that is adjustable in two dimensions causes the black and white hemispheres 230 or 220 of the gyricon balls 200 to appear as image elements, i.e., subpixels or pixels of a display.