Field emission device

A field-emission type display unit essentially consisting of three electrodes, the field-emission type display unit comprising:

• a substrate;
• a cathode layer formed on the substrate;
• an insulation layer formed on the cathode layer, and having a plurality of first openings;
• a gate electrode formed on the insulation layer, and having a plurality of second openings corresponding to the plurality of first openings, each of the second openings having the same aperture diameter as that of each of the first openings;
• an electron emission layer formed on the cathode layer exposed through the first and the second openings;
• a transparent plate disposed to face a surface of the substrate on which the cathode layer is formed, via a frame provided on a periphery of the substrate;
• an anode layer formed on a surface of the transparent plate facing a cathode layer;
• and
• a phosphor layer formed on the anode layer, wherein
• L/S≧1, where S represents the aperture diameter of the plurality of first openings, and L represents a typical shortest passing distance of the electrons emitted from the emissive material to the gate electrode.