Method of producing a bending transducer

Abstract

A bending transducer has a piezoelectret carried on a substrate of electrically insulating material. An electrically conductive coating, such as a foil, a grid foil, a grid mesh, or mutually parallel strips, connects the inner electrode of the piezoelectret to the substrate and forms electrical contact with the inner electrode at a number of points. The bending transducer is particularly suited for driving a drafting, weaving or knitting machine in the textile industry. The bending transducer is produced by connecting a substrate of electrically insulating material with a piezoelectret having an inner electrode facing towards the substrate, and placing an electrically conductive coating between the substrate and the piezoelectret such that electrical contact is made between the conductive coating and an inner electrode of the piezoelectret at a plurality of locations.

We claim:  
     
         1 . A method of producing a bending transducer, which comprises: 
 connecting a substrate of electrically insulating material with a piezoelectret having an inner electrode facing towards the substrate; and    placing an electrically conductive coating between the substrate and the piezoelectret such that electrical contact is made between the conductive coating and an inner electrode of the piezoelectret at a plurality of locations.    
     
     
         2 . The method according to  claim 1 , which comprises placing the substrate, the conductive coating, and the piezoelectret such that the substrate overlaps the conductive coating and the inner electrode at edge regions thereof.  
     
     
         3 . The method according to  claim 1 , which comprises covering exposed portions of the conductive coating and the inner electrode with an electrically insulating lacquer.  
     
     
         4 . The method according to  claim 1 , wherein the placing step comprises placing a mesh grid on a prepreg of a thermosetting plastic forming the substrate, and connecting the prepreg to the piezoelectret by heat treating with the inclusion of the mesh grid.  
     
     
         5 . The method according to  claim 1 , which comprises applying the conductive coating on the substrate in the form of a metal-gauze prepreg, and connecting the metal-gauze prepreg to the piezoelectret by heat treatment.  
     
     
         6 . The method according to  claim 3 , wherein the metal-gauze prepreg is a copper-gauze prepreg.