ES360366A1 - Dual conductor storage panel - Google Patents

Abstract

A storage panel comprises narrow opaque conductors 11 on one surface of a substrate 12, a conductive strip 13 overlaying each conductor, insulating material 15 between adjacent strips, a layer of field effect semi-conductor material 16 and electroluminescent material 14 between the strips and layer 16, the surface 19 of the panel remote from the substrate constituting a charge retaining surface. The panel is prepared by coating a polymethyl methacrylate polymer substrate with Ag flake in epoxy resin, removing unwanted Ag to form the conductors 11, depositing layers of In 2 O 3 in epoxy resin and ZnS phosphor in an epoxy binder, curing and removing portions of these layers leaving strips 13, 14. The space between the strips is filled with clear epoxy resin and a f.e.s.c. layer of ZnO powder in styrene butadiene copolymer applied. In another example Cu wire or Ag strips on a glass substrate are coated with tin oxide or Au. The conducting strips may be in grooves in the substrate, the strips and substrate may be transparent or opaque. Other f.e.s.c.'s are PbO, CdO, ZnS and CdSe and there may be an insulating layer to form the charge retaining surface if the semi-conductor cannot retain surface charge. Alternatively the s.c. may be doped to form a p-n junction which also prevents the passage of surface charge. An image is formed and stored by applying an A.C. potential between alternate conductors sufficient to produce electroluminescence, then applying an electrostatic charge pattern on the surface 19 which reduces or interrupts the current. Alternatively the surface may be unirformly charged e.g. by corona discharge and a pattern neutralized. If the A.C. potential is insufficient to produce electroluminescence positive or negative charges can be applied to an n-type orp-type s.c. to increase its conductivity and produce e.l. If the s.c. is photoconductive the surface is uniformly charged and a pattern removed by exposure to a light image or by scanning with an intensity modulated light beam. The charge pattern can be produced using recording head, a corona discharge through a mask, a moving corona discharge, a pattern of corona discharges or a scanning electron beam when the panel is used as a target for an evacuated storage tube as disclosed in Specification 1,201,374.