Abstract: Electroluminescent display with memory effect and half-tones. Each row electrode (L) is subdivided into several subelectrodes (L1,L2) and/or each column electrode (C) is subdivided into several subelectrodes (C1,C2). The row subelectrodes receive different holding voltages (Fe1,Fe2). Thus, each eldim (E) is broken down into subeldims (el1,el2,etc.) whereof the luminance is defined by the surface and the holding frequency. Thus, the juxtaposing of these luminances gives half-tones. Application to displays.

Abstract: A memory effect, monochromatic display of the photoconductor-electroluminescent type, includes on a substrate an electroluminescent layer and a photoconductor layer in stacked relation. The stack is interposed between two electrode systems used for exciting the electroluminescent layer, the latter having an emission spectrum overlapping the sensitivity spectrum of the photoconductor material. An optical filter is located between the electroluminescent layer and the display observer and permits the passage of that part of emission spectrum of the electroluminescent layer most useful for display purposes while blocking a region of the emission spectrum of the ambient illumination, the sensitivity spectrum of the photoconductor layer then being essentially contained in said region.

Abstract: A photoconductive-electroluminescent, memory effect polychromatic display defining a first and second inverted structure. The first structure incorporates a first transparent substrate equipped with a first electroluminescent layer El.sub.1 placed between a first and a second electrode system, which are connected to a first electrical source for exciting certain zones of layer El.sub.1. The second inverted structure incorporates a second substrate equipped with a second electroluminescent layer El.sub.2 and a photoconductive layer stacked on one another. These two layers are inserted between a third and a fourth electrode system which are connected to a second electrical source for exciting certain zones of the layer El.sub.2. The electroluminescent layer El.sub.1 has a monochromatic or dichromatic emission spectrum and the electroluminescent layer El.sub.2 has a monochromatic emission spectrum essentially complementary to layer El.sub.1.

Abstract: Electroluminescent display screen with a memory and a particular configuration of electrodes. The display screen comprises on a nonconducting substrate a stacked electroluminescent film and a photoconductive film, both of these films being inserted between lower transparent electrodes (12) orientated along a first direction (x) and upper electrodes (22) orientated along a second direction (y) perpendicular to the first direction, the upper and lower electrodes defining at their intersection picture elements (26), the upper electrodes (22) comprising blocks (40) of dimension D along the first direction at the display points electrically interconnected by two access strips (42a, 42b) with a width d with d<D/2, the access strips at a given block being connected by a conductive access bridge (46) parallel to the lower electrodes, the edges of these blocks (40) being situated inside the edges of the lower electrodes.

Abstract: A display includes at least one layer having a memory effect electro-optical property and enclosed between first and second families of electrodes. The display also includes a generator suitable for generating a plurality of voltages at different phases. At least one of the families of electrodes is subdivided into at least two subfamilies of parallel electrodes receiving respective different phase sustain voltages. This gives rise to a considerably drop in electrical power consumption, to an improved manufacturing yield, and makes it possible to provide larger-sized displays and/or operation at a higher image-writing speed, etc.

Abstract: An electroluminescent display device uses a photoconductive material which is of hydrogenrated and carbonated amorphous silicon of formula a-Si.sub.x C.sub.1-x ; with 1-x preferably between 0.05 and 0.50 and which has application to display functions.

Abstract: An electroluminescent display with a memory effect. The display includes an electroluminescent layer and a photoconductive layer, both of which are thin films of approximately 1 micron. The two layers are placed between two systems of electrodes which are connected to a power source. Thin dielectric film may also be part of the assembly.