Electron emission device

An electron emission device comprising:

• a first substrate;
• a second substrate facing the first substrate;
• cathode electrodes formed on the first substrate;
• electron emission regions formed on the cathode electrodes;
• an insulating layer and gate electrodes formed on the cathode electrodes and having openings exposing the electron emission regions;
• phosphor layers formed on the second substrate;
• and
• an anode electrode formed on a surface of the phosphor layers;
• wherein the distance z′ between the first and second substrates satisfies the following condition:
• 0.7d((Va−Vc)/Vg)≦z′≦1.4d((Va−Vc)/Vg),
• where Vc indicates the voltage applied to the cathode electrodes, Vg is the voltage applied to the gate electrodes, Va is voltage applied to the anode electrode, and d is the distance between the cathode and the gate electrodes, and wherein
• Vc, Vg, and Va are expressed by the unit of volts (V), and d and z′ by the unit of micrometers (μm).

A method of driving an electron emission device comprising first and second substrates facing each other, cathode electrodes formed on the first substrate, electron emission regions formed on the cathode electrodes, an insulating layer and gate electrodes formed on the cathode electrodes and having openings exposing the electron emission regions, the gate electrodes being spaced apart from the cathode electrodes at a distance d, phosphor layers formed on the second substrate, and an anode electrode formed on a surface of the phosphor layers, the method comprising:

• applying a voltage Vc to the cathode electrodes to emit electrons from the electron emission regions;
• applying a voltage Va to the anode electrodes to accelerate the emitted electrons toward the second substrate;
• and
• applying a voltage Vg to the gate electrodes to focus the emitted electrons, wherein the voltage Vg is between 0.7×(d/z)×(Va−Vc) and 1.4×(d/z)×(Va−Vc), and wherein z is a distance between the anode electrode and the cathode electrodes or a distance between the first and second substrates, and wherein Vc, Vg, and Va are expressed by the unit of volts (V), and d and z by the unit of micrometers (μm).