Field emission device

Abstract

Provided is a field emission device using carbon nanotubes. The field emission device includes a substrate, a cathode, a gate insulating layer, an electron emitter, and a gate electrode. The cathode is formed on the substrate. The gate insulating layer is formed on the cathode and has a well exposing a portion of the cathode. The electron emitter is formed on the exposed portion of the cathode. The gate electrode is formed on the gate insulating layer and has a gate hole corresponding to the well. The gate electrode further includes a cylindrical electrode part that forms a focusing electric field from the gate hole toward a proceeding path of an electron beam. Accordingly, a focusing electric field can be formed around an electron beam emitted from the electron emitter so as to converge and focus the electron beam passing through the focusing electric field. As a result, color purity, brightness, and durability can be improved.

1 - 6 . (canceled)  
     
     
         7 . A method of manufacturing a field emission device, the method comprising: 
 (a) sequentially coating a first insulating layer and a second insulating layer having a higher etching rate than the first insulating layer on a substrate on which a cathode is formed, to form a gate insulating layer;    (b) forming a first mask having a window with a predetermined diameter on the gate insulating layer to form a well in the gate insulating layer;    (c) supplying an etchant through the window to form a well that broadens upward in the gate insulating layer beneath the window of the first mask, the well exposing a portion of the cathode;    (d) depositing a gate electrode on the gate insulating layer;    (e) removing a portion of the gate electrode on the bottom and lower inner wall of the well to form a gate hole corresponding to the cathode in the gate electrode; and    (f) forming an electron emitter on the exposed portion of the cathode.    
     
     
         8 . The method of  claim 7 , after step (c), further comprising removing the first mask.  
     
     
         9 . The method of  claim 7 , wherein in step (e), a second mask having a window corresponding to the gate hole is formed, etched, and removed so as to form the gate hole.  
     
     
         10 . The method of  claim 8 , wherein in step (e), a second mask having a window corresponding to the gate hole is formed, etched, and removed so as to form the gate hole.  
     
     
         11 . The method of  claim 7 , wherein step (f) comprises forming a third mask on the gate electrode to expose only a portion of the cathode and cover the remaining area of the cathode so as to form the electron emitter.  
     
     
         12 . The method of  claim 8 , wherein step (f) comprises forming a third mask on the gate electrode to expose only a portion of the cathode and cover the remaining area of the cathode so as to form the electron emitter.  
     
     
         13 . The method of  claim 9 , wherein step (f) comprises forming a third mask on the gate electrode to expose only a portion of the cathode and cover the remaining area of the cathode so as to form the electron emitter.  
     
     
         14 . The method of  claim 11 , wherein in step (f), after forming the third mask, a carbon nanotube paste containing photoresist is coated, and then patterned by photolithography so as to form the electron emitter.  
     
     
         15 . The method of  claim 13 , wherein in step (f), after forming the third mask, a carbon nanotube paste containing photoresist is coated, and then patterned by photolithography so as to form the electron emitter.