Low-voltage field transmission cathode-ray tube

In the invention, Funicular nano carbon tubes as field emission cathode arranged in array mode are assembled on conducting substrate. Axis direction of carbon tubes is perpendicular to surface of substrate. Anode with voltage applied is fixed on a sustainer arranged above array of nano carbon tubes in parallel. The sustainer is in open-ended tubular structure, and lower end of the tubular structure is installed on edge of a conducting substrate. Upper end as a window for focusing electrons is in bottleneck structure. Leaded from the conducting substrate and tubular structure, poles A, B through wires are connected to external power source. The invention reduces operating voltages of X ray tube so as to realize miniaturization and raise resolution.