Abstract: The system enables the making of half-tones by using the control circuits of the matrix which are not usually designed for this purpose while producing no flicker effect. The system has a memory image with N (greater than or equal or 2) memory planes to store therein light information relating to each pixel in an N-bit word. The planes are read sequentially and thus make N-1 half-tones. In the simplest case (n=2), two planes are used and a first image is produced where any pixel is formed by a first bit, extracted from a first plane, and is preceded and followed, in rows as well as in columns, by a pixel formed by a first bit extraced from the other plane. The addressing is then determined to produce a second image by extracting, in reverse and respectively by each pixel, the second luminance bit in the other memory plane not used for the first image.

Abstract: The device of the invention comprises mainly a liquid crystal screen illuminated by a light source. An electrically controlled modulating device is placed between the source and the screen. Depending on the desired illuminating intensity, the electrical signal will be adapted to the modulating device. The modulating device may comprise essentially a liquid crystal cell.

Abstract: A method of fabrication of non-linear control elements as applicable to electrooptical displays and in particular to large-area liquid-crystal displays of the flat-panel type, in which the following layers are stacked successively on a substrate: a first layer of metallic material, a first layer of undoped amorphous semiconductor material, a layer of doped amorphous semiconductor material, a second layer of undoped amorphous semiconductor material, and a second layer of metallic material.

Abstract: In a method of fabrication of non-linear control elements for a flat display screen of the liquid crystal type, successive layers of n.sup.30 doped amorphous semiconductor, of undoped amorphous semiconductor and of metal are deposited on a substrate, whereupon the control elements are formed by masking and etching. The flanks of the control elements are then isolated, whereupon the electrodes and control leads are formed by deposition and etching.

Abstract: Diode-type control matrix arrays for electrooptical flat-panel screens which find application in liquid-crystal displays are fabricated by depositing a layer of conductive material on a substrate and etching the control electrodes and control leads in this layer. The entire structure is then coated with an undoped amorphous semiconductor layer, with a doped amorphous semiconductor layer, and with a second layer of conductive material. In these three layers are etched terminal areas (or control elements) for connecting the control electrodes to the control leads.

Abstract: The invention relates to devices by means of which it is possible to cause fluid globules to circulate within a capillary space by means of pairs of electrodes establishing capture sites. The invention provides a device in which the electrodes of two successive pairs have in common at least one indentation comprising a convex part and a concave part. The invention is applicable, in particular, to the visual display and storage of electrical data by means of movable indices in the form of globules.