Abstract: An apparatus is disclosed for controlling the brightness of a matrix-addressed flat panel CRT display of a type having intersecting column and row conductors forming, respectively, the gate and cathode electrodes of a field electron emission array. The brightness control is effected by controlling the voltages applied to the drive lines of the intersecting conductors. A waveform having progressively increasing voltage steps is sequentially applied to the row conductors. The voltages at each of the steps are preferably selected to enable electron beam currents which provide brightness levels which are twice the brightness of the previous step. Binary-coded brightness control signals are simultaneously applied to all of the column conductors. The voltages of the stepped waveform and the binary-coded signals comprise a combination of video information data and correction data which compensate for irregularities in the current emitting structure at the selected conductors.

Abstract: An apparatus is disposed for controlling the brightness of a matrix-addressed flat panel CRT display of a type having intersecting column and row conductors forming, respectively, the gate and cathode electrodes of a field electron emission array. The brightness control is effected by controlling both the duty cycle and the voltage applied to the drive lines of the intersecting conductors. A periodic staircase waveform having progressively increasing voltage steps is sequentially applied to the row conductors. The voltages at each of the steps are preferably selected to enable electron beam currents which provide brightness levels which are twice the brightness of the previous step. Binary-coded video brightness data are simultaneously applied to all of the column conductors. The combined voltages at the intersections of the selected conductors cause a sequence of electron emissions onto luminescing means which result in a corresponding sequence of illumination intervals.