Fluorescent display tube with pulse voltage driving to the cathodes at different times

A fluorescent display tube comprising:

• an envelope allowing an interior thereof to be held in a high-vacuum state;
• an anode in which a phosphor layer is adhered onto an anode conductor provided on an inner surface of the envelope;
• a plurality of filament-shaped cathodes placed above the anode in the envelope by a pair of support bodies supporting both ends of each of the cathodes;
• an anode driving unit for driving the anode;
• and
• a cathode driving unit for driving the cathodes, wherein
• by driving the anode and the cathodes by the anode driving unit and the cathode driving unit, respectively, electrons discharged from the cathodes are made to collide against the anode so as to allow the phosphor layer to emit light, and wherein
• at least one of the pair of support bodies is electrically divided for each of the cathodes, and the cathode driving unit gives pulse voltages to each of the cathodes at different timing.