Matrix display device

Claim 1

A matrix display device comprising a display cell constituted by two transparent insulating walls and by a material incorporating a plurality of zones distributed in matrix-like manner and having a first group of p rows of parallel electrodes placed on one of said insulating walls and a second group of q columns of parallel electrodes placed on the other of said insulating walls, said p rows and said q columns crossing one another, a zone x i y j being defined by the region of the material covered by row x i in which i is an integer such that 1≦i≦p, and by column y j in which j is an integer such that 1≦j≦q, and means making it possible to supply excitation signals to the electrodes, said material having an optical property dependent on said excitation signals, wherein the device also comprises a third group of p rows of parallel electrodes, whose orientation is identical to that of the first group and placed on the second group of electrodes, whilst being electrically insulated from said second group by an insulating layer, so that the material is inserted between the first group of electrodes and the third group of electrodes and is in contact with said first and third groups of electrodes wherein the third group of electrodes is in the form of a matrix of point electrodes, each of said point electrodes being provided with a switch being operable to join said each point electrode to a constant potential conductor common to all the point electrodes of the same row in the group or to electrically insulate said each point electrode, with the control of each said switch being effected by a control conductor common to all the point electrodes in the same row of said third group.