Plasma generating electrode assembly

Abstract

A plasma glow discharge and/or dielectric barrier discharge generating assembly ( 1 ) comprising at least one pair of substantially equidistant spaced apart electrodes ( 2 ), the spacing between the electrodes being adapted to form a plasma zone ( 8 ) upon the introduction of a process gas and enabling passage, where required, of gaseous, liquid and/or solid precursor(s) characterized in that at least one of the electrodes ( 2 ) comprises a housing ( 20 ) having an inner ( 5 ) and outer ( 6 ) wall, wherein the inner wall ( 5 ) is formed from a non-porous dielectric material, and which housing ( 20 ) substantially retains an at least substantially non-metallic electrically conductive material.

1 . A plasma discharge generating assembly ( 1 ) comprising at least one pair of substantially equidistant spaced apart electrodes ( 2 ), the spacing between the electrodes being adapted to form a plasma zone ( 8 ) upon the introduction of a process gas and enabling passage, where required, of gaseous, liquid and/or solid precursor(s) characterized in that at least one of the electrodes ( 2 ) comprises a housing ( 20 ) having an inner ( 5 ) and outer ( 6 ) wall, wherein the inner wall ( 5 ) is formed from a non-porous dielectric material, and which housing ( 20 ) substantially retains an at least substantially non-metallic electrically conductive material.  
   
   
       2 . An assembly in accordance with  claim 1  wherein the at least one pair of electrodes ( 2 ) is further defined as a plurality of pairs of electrodes ( 2 ).  
   
   
       3 . An assembly in accordance with  claim 1  wherein the at least substantially non-metallic electrically conductive material is a polar solvent.  
   
   
       4 . An assembly in accordance with  claim 3  wherein the polar solvent is water, an alcohol and/or glycol.  
   
   
       5 . An assembly in accordance with  claim 3  wherein the at least substantially non-metallic electrically conductive material is a salt solution.  
   
   
       6 . An assembly in accordance with  claim 1  wherein the at least substantially non-metallic electrically conductive material is selected from a conductive polymer paste and a conductive adhesive.  
   
   
       7 . An assembly in accordance with  claim 6  wherein the conductive polymer paste and conductive adhesive are curable.  
   
   
       8 . An assembly in accordance with  claim 1  wherein each housing ( 20 ) has an inlet ( 3 ) or an inlet ( 3 ) and outlet ( 4 ) such that the at least substantially non-metallic electrically conductive material may be introduced into and removed from the electrode ( 2 ) by way of the inlet ( 3 ) and/or outlet ( 4 ).  
   
   
       9 . An assembly in accordance with  claim 1  wherein the outer wall ( 6 ) is a heat sink.  
   
   
       10 . An assembly in accordance with  claim 1  wherein the functional size of each electrode ( 2 ) is varied by the introduction and removal of the at least substantially non-metallic electrically conductive material.  
   
   
       11 . An assembly in accordance with  claim 8  wherein one or more cooling coils ( 25 ) or cooling fins ( 30 ) is/are fixed to the outer wall ( 6 , 6   a ) to cool the at least substantially non-metallic electrically conductive material and assembly ( 1 ).  
   
   
       12 . An assembly in accordance with  claim 1  wherein the electrodes ( 2 ) are in the form of concentric cylinders ( 32 ,  34 ).  
   
   
       13 . An assembly in accordance with  claim 1  wherein each electrode ( 2 ) is cuboidal and is made from a single section of dielectric material ( 67 ) apart from the outer wall ( 6 , 6   a ) and each electrode ( 2 ) has a chamber ( 11   b ) defined within the dielectric material ( 67 ) for receiving the at least substantially non-metallic electrically conductive material.  
   
   
       14 . An atmospheric pressure plasma assembly comprising a first and second pair of parallel spaced-apart planar electrodes ( 120   a ,  126   a  and  126   b ,  120   b ), the spacing between each of the first and second pairs of electrodes forming a first and second plasma zones ( 125 , 160 ) characterised in that the assembly further comprises a means of transporting a substrate ( 170 , 171 , 172 ) successively through the first and second plasma zones ( 125 , 160 ) and an atomiser ( 174 ) adapted to introduce gaseous or atomised liquid and/or solid coating making materials into one of the first or second plasma zones.  
   
   
       15 . Use of the assembly ( 1 ) of  claim 1  for the treatment of films, webs, non-woven and woven fabrics and/or metal foils.  
   
   
       16 . Use of the assembly ( 1 ) of  claim 1  for the treatment of powders and particulate materials.  
   
   
       17 . A pair of substantially equidistant spaced apart electrodes ( 2 ), characterized in that at least one of the electrodes ( 2 ) comprises a housing ( 20 ) having an inner ( 5 ) and outer ( 6 ) wall, wherein the inner wall ( 5 ) is formed from a non-porous dielectric material, and which housing ( 20 ) substantially retains an at least substantially non-metallic electrically conductive material.  
   
   
       18 . A method of plasma treating a substrate with the plasma discharge generating assembly of  claim 1  said method comprising passing the substrate through the plasma zone ( 8 ) formed by affecting a plasma between the electrodes ( 2 ).  
   
   
       19 . An assembly in accordance with  claim 1  selected from the group of plasma glow discharge generating assemblies and dielectric barrier generating assemblies.