Method for fabricating nanotube electron emission source by scanning-matrix type electrophoresis deposition

Abstract

A scanning-matrix type electrophoresis deposition method fabricates nanotube electron emission source. During the electrophoresis deposition process, the electrical field is applied to a single pixel to localize the electrophoresis deposition. The cathode strips on the cathode plate are vertical to the anode strips of the anode plate. A sequential pulse voltage signal is applied to the cathode strips and the anode strips. Therefore only one electrical field is present for one pixel defined by the cathode strip cross with the anode strip at one time and nanotube is formed at that pixel.

1 . A method for fabricating nanotube electron emission source by scanning-matrix type electrophoresis deposition, comprising: 
 connecting anode ends of a power source to anode strips of an anode plate, connecting cathode ends of the power source to one input ends of signal amplifiers, connecting output ends of the signal amplifiers to a plurality of cathode strips of a cathode plate, placing the anode strips vertical to the cathode strips, connecting a signal generator to another input ends of the signal amplifiers;    providing an electrophoresis tank with electrophoresis solution therein and placing the anode plate and the cathode plate parallel in the electrophoresis tank;    outputting voltages from anode ends of the power source to the anode strips, the signal generator sending pulse voltage signal to one of the signal amplifiers and amplified by the one of the signal amplifiers such that one of the cathode strip is conducted while the remaining cathode strips are not conducted, whereby only one electrical field is present for one pixel at one time and nanotube is formed at that pixel; and    conducting next cathode strip successively and keeping the remaining cathode strips being non-conducted to fabricate nanotube electron emission source in scanning-matrix manner.    
   
   
       2 . The method as in  claim 1 , wherein the power source is a scanning power source to provide sequential voltage signals to complete global area electrophoresis in a period of time, wherein the pulse voltage provided by anode end is 120V.  
   
   
       3 . The method as in  claim 1 , wherein the anode strips are formed conversely on an insulating plate.  
   
   
       4 . The method as in  claim 3 , wherein the insulating plate is a glass plate and the anode strips are formed by screen-printing or lithography.  
   
   
       5 . The method as in  claim 1 , wherein the cathode strips are formed longitudinally on the cathode plate.  
   
   
       6 . The method as in  claim 1 , wherein the cathode strip is a semi-finished product with gate and sacrifice layer.  
   
   
       7 . The method as in  claim 6 , wherein the sacrifice layer is functioned to prevent unwanted deposition such as gate and dielectric layer.  
   
   
       8 . The method as in  claim 6 , further comprising a step of removing the sacrifice layer.  
   
   
       9 . The method as in  claim 1 , wherein the cathode plate and the anode plate are placed in the electrophoresis tank parallel with 3-5 cm separation therebetween.  
   
   
       10 . The method as in  claim 1 , wherein the electrophoresis solution used alcohol as solution, the electron emission source uses powder material made of nanotube formed by arc discharge, the nanotube has average tube length below 5 μm and average diameter below 100 nm and has multiple wall, the nanotube has an additive concentration of 0.1%˜0.005%.  
   
   
       11 . The method as in  claim 10 , wherein the additive concentration is preferably 0.02%  
   
   
       12 . The method as in  claim 1 , wherein the solution further comprises chargers, the charger uses metal salt being conductive after electrophoresis.  
   
   
       13 . The method as in  claim 12 , wherein the metal salt is one of InCl and indium nitride or other salt with tin.  
   
   
       14 . The method as in  claim 12 , wherein the charger is InCl salt with 0.1-0.005% weight concentration and glass power with at 5% weight concentration to enhance adhesion.  
   
   
       15 . The method as in  claim 14 , wherein the charger is preferably with 0.01% weight concentration  
   
   
       16 . The method as in  claim 1 , wherein the signal generator generates a continuous square wave signal.  
   
   
       17 . A method for fabricating nanotube electron emission source by scanning-matrix type electrophoresis deposition, comprising: 
 connecting anode ends of a power source to anode strips of an anode plate, connecting cathode ends of the power source to one input ends of signal amplifiers, connecting output ends of the signal amplifiers to a plurality of cathode strips of a cathode plate, placing the anode strips vertical to the cathode strips, connecting a signal generator to another input ends of the signal amplifiers;    providing an electrophoresis tank with electrophoresis solution therein and placing the anode plate and the cathode plate parallel in the electrophoresis tank;    outputting voltages from anode ends of the power source to the anode strips, the signal generator sending pulse voltage signal to one of the signal amplifiers and amplified by the one of the signal amplifiers such that one of the signal amplifiers has not amplification and one cathode strip is at high level while the remaining cathode strips are at low level, whereby only one electrical field is present for one pixel defined by the cathode strip with low level and anode strip with high level at one time and nanotube is formed at that pixel; and    biasing next cathode strip successively to be low level and keeping the remaining cathode strips being high level to fabricate nanotube electron emission source in scanning-matrix manner.