Display bias arrangement

An improved display bias arrangement is provided using a DC filament voltage in conjunction with stepped grid voltages to maintain even illumination. In a VF display there is a directly heated cathode (filament), an anode and a grid. If a DC filament voltage is used, one end of the cathode will be at different potential than the other, thus resulting in a variation in anode-to-cathode potential across the display. This varying potential causes electrons to hit the anode with varying speed, causing a variation in display intensity. In this invention, the cathode (filament) is supplied with a DC voltage and the grid of each segment is supplied with a different voltage, thereby equalizing the anode-to-cathode potential for each display digit. In a first embodiment, resistor networks are used to equalize the anode-to-cathode voltages. In a second embodiment, diode networks are used to equalize the anode-to-cathode voltages.