Dielectric composite and a method of manufacturing a dielectric composite

Abstract

A composite for a transducer facilitates an increased actuation force as compared to similar prior art composites for transducers. The composite facilitates increased compliance of the transducer in one direction, an improved reaction time as compared to similar prior art composites for transducers, and provides an increased lifetime of the transducer in which it is applied.

1 . A method of making a polymeric composite, the method comprising:
 providing a shape defining element having a surface pattern of raised and depressed surface portions,   providing a liquid polymer composition onto the surface pattern,   curing the liquid polymer to form a polymeric film having a surface with a replicated pattern of raised and depressed surface portions in such a manner that the raised and depressed surface portions obtain a shape and/or size which varies periodically along at least one direction of the surface, and   depositing a first electrically conductive layer onto the replicated surface pattern so that the electrically conductive layer is shaped by the replicated pattern.   
     
     
         2 . The method according to  claim 1 , wherein the step of coating the film with a first electrically conductive layer comprises the step of using a shape of the polymeric film to shape the electrically conductive layer. 
     
     
         3 . The method according to  claim 1 , wherein the electrically conductive layer is deposited on the film in a physical vapour deposition process. 
     
     
         4 . The method according to  claim 1 , wherein the electrically conductive layer is deposited onto the film in a thickness of 0.1-0.01 micrometer. 
     
     
         5 . The method according to  claim 4 , wherein the thickness is controlled by quartz crystal micro balance. 
     
     
         6 . The method according to  claim 4 , wherein the electrically conductive layer is made in a sputtering process. 
     
     
         7 . The method according to  claim 4 , wherein the electrically conductive layer is made in an electron beam process. 
     
     
         8 . The method according to  claim 1 , wherein the step of depositing an electrically conductive layer comprises depositing a first electrically conductive layer and depositing a second electrically conductive layer on top of the first electrically conductive layer. 
     
     
         9 . The method according to  claim 8 , wherein the step of depositing the first electrically conductive layer and the step of depositing a second electrically conductive layer are performed at different depositing rates. 
     
     
         10 . The method according to  claim 8 , wherein the step of depositing a first electrically conductive layer comprises depositing a first material, and the step of depositing a second electrically conductive layer comprises depositing a second material. 
     
     
         11 . The method according to  claim 1 , wherein the film is provided by use of a liquid polymer and a reverse roll process. 
     
     
         12 . The method according to  claim 1 , wherein the film is provided by use of a liquid polymer and a gravure roll process. 
     
     
         13 . The method according to  claim 1 , wherein the film is provided by use of a liquid polymer and a slot die coating process. 
     
     
         14 . The method according to  claim 11 , wherein the liquid polymer comprises a solvent. 
     
     
         15 . The method according to  claim 1 , wherein the film is exposed to heat or ultraviolet light to initiate cross-linking. 
     
     
         16 . The method according to  claim 1 , wherein the film is treated with a plasma to improve adhesion of the electrically conductive layer. 
     
     
         17 . The method according to  claim 16 , wherein the treatment is conducted with a glow discharge which is known to generate mild plasma. 
     
     
         18 . The method according to  claim 16 , wherein an adhesion promoter is applied to at least said portion of the film after the step of plasma treating and before the step of depositing the electrically conductive layer thereon. 
     
     
         19 . The method according to  claim 18 , wherein the adhesion promoter is provided by applying a layer of chromium or titanium between the film and the electrically conductive layer. 
     
     
         20 . The method according to  claim 18 , wherein the adhesion promoter is applied to the film of the dielectric material in a physical vapour deposition process.