GB1252806A - - Google Patents

Abstract

1,252,806. Electroluminescence. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. 3 Feb., 1969 [2 Feb., 1968], No. 5742/69. Heading C4S. [Also in Division H1] A photoconductive layer produced by coating a surface with a mixed suspension of photoconductive particles, binder and a volatile diluent and volatilizing the diluent, is similarly coated with a second photoconductive layer, of the same or different material to the first, and the binders of both layers are then set by a single heat treatment. An image converter, Fig. 3, is produced by applying a transparent electrode 5, an electroluminescent layer 4 and an optical feedback prevention layer 3, which may be of a reflective material, e.g. barium titanate, or an opaque material in a binder, to a transparent substrate 6, e.g. of glass. A spacer frame 7 having an upper section (7<SP>1</SP>), not shown, is adhesively secured to the surface and filled with a mixture comprising photoconductive particles, epoxy resin as a binder, and a volatile diluent, e.g. acetone or alcohol, and levelled with a doctor blade. The layer mixture is then dried so that it shrinks to the level of the lower frame member 7 to form layer 22. The upper frame member (7<SP>1</SP>) is removed and a wire 1 is wound round the structure to form a foraminous electrode. A second layer 21 of photoconductor is applied over the electrode using a similar method and the structure is heated to cure the binders of the layers 21 and 22. A conductive paint, e.g. containing silver, is applied to the ends of the substrate to interconnect the turns of wire 1 and the excess portions of wire 1 are removed. An alternative construction in which the upper photoconductive layer extends between the foraminous electrode and the lower photoconductive layer, Fig. 1 (not shown), is produced by selecting the thicknesses of the spacer members and the dilution of the photoconductive mixture so that the lower photoconductive layer shrinks below the level of the top of the lower spacer frame (7). The upper photoconductive layer is then formed, the upper spacer frame is removed, foraminous electrode is applied a further photoconductive layer is applied over the electrode, and the layers are set by heating. The foraminous electrode 1 may also comprise a grid and the transparent electrode 5 may be a layer of stannic oxide.