Field emission cathode device and field emission display using the same

A field emission cathode device, comprising:

• a cathode substrate;
• a gate electrode located on the cathode substrate;
• a first dielectric layer located on the gate electrode and defining a first opening such that a gate electrode exposed portion is exposed;
• a cathode electrode located on the first dielectric layer and defining a second opening in communication with the first opening;
• and
• an electron emission layer located on the cathode electrode;
• wherein the cathode electrode further defines a sixth opening about the second opening, and the first dielectric layer further defines a seventh opening in communication with the sixth opening and about the first opening, wherein the sixth opening divides the cathode electrode into a first portion, a second portion and at least one connecting portion;
• the second portion is spaced from the first portion and electrically connected to the first portion by the at least one connecting portion;
• the second portion is located between the first dielectric layer and the electron emission layer;
• and the electron emission layer is located only on the second portion.

A field emission display, comprising:

• a cathode substrate;
• a plurality of gate electrodes located on the cathode substrate parallel and spaced from each other;
• a plurality of cathode electrodes located in parallel with and spaced from each other, and vertical to the plurality of gate electrodes, wherein each intersection of the plurality of cathode electrodes and the plurality of gate electrodes defines a pixel unit;
• a first dielectric layer located between the plurality of gate electrodes and the plurality of cathode electrodes, wherein a first opening is defined by the first dielectric layer and the plurality of cathode electrodes corresponding to each pixel unit, wherein in each pixel unit, the cathode electrode further defines a sixth opening about the first opening, the sixth opening divides the cathode electrode into a first portion, a second portion and at least one connecting portion;
• and the second portion is spaced from the first portion and electrically connected to the first portion by the at least one connecting portion;
• a plurality of ring-shaped electron emission layers located on the plurality of cathode electrodes, wherein the second portion is located between the first dielectric layer and the plurality of ring-shaped electron emission layers, and each of the plurality of ring-shaped electron emission layers is located corresponding to each pixel unit and only on the second portion;
• a second dielectric layer located on the plurality of cathode electrodes;
• a focus electrode located on the second dielectric layer, wherein a second opening is defined by the focus electrode and the second dielectric layer corresponding to each pixel unit to expose the plurality of ring-shaped electron emission layers;
• an anode substrate spaced from the cathode substrate to define a vacuum space;
• an anode electrode located on the anode substrate and spaced from the cathode substrate;
• and
• a plurality of fluorescent layers located on the anode electrode, wherein each of the plurality of fluorescent layers corresponds to one of the plurality of ring-shaped electron emission layers.