Passive and active diamond-based electron emitters and ionizers

Abstract

A triple-point cathode coating and method wherein electrically conductive NEA diamond particles cast or mixed with the adhesive medium and electrically insulative NEA diamond particles are cast or mixed with the adhesive medium to form a plurality of exposed junctions between electrically conductive diamond particles and electrically insulative diamond particles to reduce any electrical charges on a structure coated with the coating.

What is claimed is: 
     
         1 . A triple-point cathode coating comprising:
 an electrically conductive adhesive medium;   electrically conductive NEA diamond particles cast or mixed with the adhesive medium;   electrically insulative NEA diamond particles cast or mixed with the adhesive medium; and   a plurality of exposed junctions between electrically conductive diamond particles and electrically insulative diamond particles; or   a plurality of exposed junctions between electrically insulative diamond films deposited on top of electrically conductive diamond films (or vice versa), with both deposited on an electrically conductive substrate, where the junctions between conductive and insulative diamonds are formed by etching away portions of one film to reveal portions of the other; and   either coatings or etched film junctions to reduce any electrical charges on a structure coated with the coating or with etched film junctions' adhered to them using an electrically conductive adhesive.   
     
     
         2 . The coating of  claim 1  in which the electrically conductive NEA diamond particles contact electrically insulative NEA diamond particles at locations not submerged in the adhesive medium. 
     
     
         3 . The coating of  claim 1  in which the electrically conductive NEA diamond particles and the electrically insulative particles have a grit size of between 0.5 microns to 150 microns. 
     
     
         4 . The coating of  claim 1  in which the electrically conductive NEA diamond particles and the electrically insulative diamond particles are mixed together before casting or mixing them with the adhesive medium. 
     
     
         5 . The coating or films of  claim 1  in which the adhesive medium includes silver. 
     
     
         6 . The coating of  claim 1  in which the junctions between electrically insulative and electrically conducting diamonds are formed from synthetic diamond films by lithographic methods, in which portions of an electrically insulative diamond film deposited on top of an electrically conducting diamond film are etched away to reveal triple-point junctions between the electrically insulative and conductive diamond films and free space. 
     
     
         7 . A cold cathode field emission electron gun:
 a substrate; and   a cathode coating associated with the substrate, the coating including:
 an electrically conductive adhesive medium; and 
 electrically conductive NEA diamond particles cast or mixed with the adhesive medium or attached on top of the medium. 
   
     
     
         8 . The electron gun of  claim 7  further including:
 a conducting gate electrode supported above the coating; and 
 a voltage source connected between the gate electrode and the coating to produce energetic free electrons by field emission from the diamonds' tips; and to transport a field of emitted electrons through the gate electrode into free space after acceleration by the voltage placed between the gate electrode and conducting diamond particles. 
 
     
     
         9 . The electron gun of  claim 8  further includes a piezoelectric material upon which the coating or the gate electrode is placed. 
     
     
         10 . The electron gun of  claim 9  further including a voltage source for the piezoelectric material to adjust the distance between the gate electrode and the diamond coating to optimize field emission of electrons from the coating. 
     
     
         11 . The electron gun of  claim 7  further including an electrically conducting layer behind the coating. 
     
     
         12 . The electron gun of  claim 7  in which the electrically conductive NEA diamond particles are not submerged in the adhesive medium. 
     
     
         13 . The electron gun of  claim 7  in which the electrically conductive NEA diamond particles have a grit size of between 0.5 microns to 150 microns. 
     
     
         14 . The electron gun of  claim 7  in which the electrically conductive NEA diamond particles are mixed with electrically conducting adhesive before casting or mixing them with the adhesive medium. 
     
     
         15 . The electron gun of  claim 7  in which the adhesive medium includes silver. 
     
     
         16 . A method of producing a cold cathode, the method comprising:
 preparing an electrically conductive adhesive medium; and   casting or mixing electrically conductive NEA diamond particles with the adhesive medium; and   wherein there are a plurality of exposed sharp NEA diamond particle tips.   
     
     
         17 . The method of  claim 16  in which the electrically conductive NEA particles are not submerged in the adhesive medium but are rather exposed to a gate electrode. 
     
     
         18 . The method of  claim 16  in which the electrically conductive NEA diamond particles have a grit size of between 0.5 microns to 150 microns. 
     
     
         19 . The method of  claim 16  in which the electrically conductive NEA diamond particles is mixed with the electrically conducting adhesive medium before casting onto a substrate. 
     
     
         20 . The method of  claim 16  in which the adhesive medium includes silver. 
     
     
         21 . The method of  claim 16  in which preparing the adhesive medium includes mixing a two part epoxy. 
     
     
         22 . The method of  claim 16  in which the electrically conductive NEA diamond particles are mixed with the adhesive medium, and then additional solvent is added to that mixture to produce a low-viscosity final mixture.