Patent ID: 8477156

Claim:
A method to drive a matrix display device capable of displaying grey levels at one or more electron sources, including one or more row electrodes and one or more column electrodes, the electron source being defined at an intersection of a row electrode and a column electrode, the method comprising: for a row selection period, a row select potential is applied to a selected row electrode, during the period a voltage is simultaneously applied to a column electrode, the voltage depending on the grey level to be displayed by the electron source at the intersection of the selected row electrode and the column electrode, wherein the grey levels to be displayed are divided into only first and second grey level families irrespective of a number of grey levels, the first grey level family grouping together a plurality of darkest grey levels, the second grey level family grouping together a plurality of least dark grey levels; for each of the grey levels to be displayed by the electron source that belong to the first family, the voltage of the column electrode, right at the start of the row selection period, is brought from an intermediate potential, lying between a second potential used to display black and a first potential used to display white, to the second potential irrespective of the grey level to be displayed and it is then returned to the intermediate potential after a time equal to or less than the row selection period and which depends on the grey level to be displayed; for each of the grey levels to be displayed that belong to the second family, the voltage of the column electrode is brought from the intermediate potential to the first potential at an instant in the row selection period which depends on the grey level to be displayed, and it is returned to the intermediate potential at the end of the row selection period irrespective of the grey level to be displayed; and wherein, after the row selection period, the row electrode which was selected is brought to a discharge potential and it is then set at high impedance.