Electrophoretic display panel with internal mesh background screen

An electrophoretic display comprising:

• (a) a fluid-tight envelope having a portion thereof which is at least partially transparent;
• (b) an electrophoretic fluid contained within said envelope, said fluid having pigmented particles suspended therein;
• (c) a plurality of elongated substantially parallel horizontal conductor members disposed within a first plane and at least partially contained within said envelope;
• (d) a plurality of elongated substantially parallel vertical conductor members at least partially contained within said envelope electrically insulated from said horizontal members and disposed within a second plane, said first and said second planes being substantially parallel and in proximity to each other, said plurality of horizontal members and said plurality of vertical members forming a matrix with a plurality of intersections when viewed along a line perpendicular to said first and said second planes;
• (e) a substantially planar conductor member disposed within a third plane proximate and substantially parallel to said second plane and at least partially contained within said envelope;
• and
• (f) a perforated electrically conductive screen disposed between said vertical members and said planar member, said screen allowing said pigment particles to pass through the perforations thereof and being at least partially opaque when viewed through said transparent portion of said envelope, each of said vertical and said horizontal members in said matrix and said screen being selectively electrically chargeable to induce movement of said particles within said fluid, said particles being visible through said transparent portion of said envelope.

A method for operating an electrophoretic display of the type having a cathode matrix comprising a plurality of parallel lines arranged in a given direction, with a grid matrix insulated from said cathode matrix and comprising a plurality of parallel lines each perpendicular to said cathode lines to form an X-Y addressing matrix with a conventional anode electrode separated from said X-Y matrix with the space between said anode electrode and said X-Y matrix accommodating an electrophoretic dispersion including pigment particles suspended in a fluid, and a screen composed of an electrically conductive material disposed within said space between said anode electrode and said X-Y matrix, said screen allowing said pigment particles to pass therethrough under the control of said anode and said X-Y matrix, said screen being at least partially opaque and providing a contrasting background for said pigment particles includes the steps of;

• (a) electrically connecting said cathode matrix, said grid matrix, said screen and said conventional anode to a source of electrical potential energy, said source providing a range of independent and selectively variable voltages to each of said cathode matrix, said grid matrix, said screen and said anode under the control of control means for controlling the voltage level supplied by said source to each of said cathode matrix, said grid matrix, said screen and said anode;
• and
• (b) controlling said source of electrical potential energy with said control means such that voltage levels are applied to said cathode matrix, said grid matrix, said screen and said anode for performing display operations.