Shielded flexible circuits and methods for manufacturing same

Abstract

A shielded flexible cable having a plurality of shielded electronic circuits in close proximity to one another such that signals transmitted on one of said plurality of shielded electronic circuits do not substantially interfere with signals transmitted on the other of said plurality of electronic circuits comprising a polyimide support member supporting a plurality of etched copper traces on a first side of said polyimide support member and a copper layer on a second side of said polyimide support member. Said polyimide support member is flexible along at least one axis, and said plurality of etched copper traces and said copper layer substantially as flexible as said polyimide support member.

1 . A shielded flexible circuit having a plurality of shielded electrical conductors in close proximity to one another such that signals transmitted on one of said plurality of shielded electronic circuits do not substantially interfere with signals transmitted on the other of said plurality of electronic conductors comprising:
 a support member supporting a plurality of etched copper traces on a first side of said support member and a copper layer on a second side of said support member, at least some of said traces serving as said electrical conductors;   said support member flexible along at least one axis;   said plurality of etched copper conductors and said copper layer substantially as flexible as said support member;   an electrically insulative material in substantial proximity to each of said plurality of copper traces serving as electrical conductors so as to electrically insulate each of said electrical conductors;   a conductive shield over said electrical insulation material and surrounding a portion of each of said etched copper conductors along substantially the entire length of each of said plurality of copper traces;   said conductive shield in electrical communication with said copper layer via discontinuities in said support member, said conductive shield and said copper layer providing a substantially 360° electrical shield around each of said etched copper traces serving as electrical conductors;   said electrically insulative material physically located between said conductive shield and each of said plurality of copper traces serving as electrical conductors;   a first dielectric layer covering substantially the entire exposed surface of said conductive shield; and   a second dielectric layer covering substantially the entire exposed surface of said copper layer.   
   
   
       2 . The shielded flexible circuit of  claim 1 , wherein said conductive shield includes:
 alternate etched copper traces not serving as said electrical conductors; and   discontinuities in the electrically insulated material over said alternate etched copper traces so that said conductive shield includes (i) said copper layer, (ii) respective traces located on each side of each trace serving as an electrical conductor, and (iii) conductive material in said discontinuates to provide a 360° conductive shield around each of said etched copper traces serving as electrical conductors.   
   
   
       3 . The shielded flexible circuit of  claim 1 , wherein substantially all of said etched copper traces serve as said electrical conductors, said flexible circuit having
 interstices between each of said plurality of insulated copper traces, and   said conductive shield includes (i) said copper layer, (ii) a layer of conductive material over said copper traces, and (iii) conductive material in said interstices.   
   
   
       4 . The shielded flexible circuit of  claim 3 , wherein said interstices are channels. 
   
   
       5 . The shielded flexible circuit of  claim 4 , wherein said channels are located in said support member. 
   
   
       6 . The shielded flexible circuit of  claim 1 , wherein said support member is formed by a non-conductive flexible material. 
   
   
       7 . The shielded flexible circuit of  claim 1 , wherein said flexible support member is a polyimide film. 
   
   
       8 . The shielded flexible circuit of  claim 1 , wherein said conductor shield includes a silver based material. 
   
   
       9 . A method of forming a shielded flexible circuit, the method comprising:
 forming a first conductor, a second conductor and a third conductor from a conductive material adhered to a first side of a flexible support member, said second conductor located between said first and third conductors and electrically insulated from said first and third conductors;   adhering a first non-conductive layer to the first side of said flexible support member, said first non-conductive layer in contact with said first conductor;   adhering a first conductive layer to said first non-conductive layer, said first conductive layer in communication with said first and third conductors; and   adhering a second conductive layer to a second side of said flexible support member, said second conductive layer in communication with said first and third conductors and electrically insulated from said second conductor.   
   
   
       10 . The method of  claim 9 , wherein forming said first, second, and third conductors comprises etching a copper trace. 
   
   
       11 . The method of  claim 9 , wherein said flexible support member is a polyimide film. 
   
   
       12 . The method of  claim 9 , wherein said first and third conductors are electrically grounded. 
   
   
       13 . The method of  claim 9 , wherein said first conductive layer is a silver based material. 
   
   
       14 . The method of  claim 9 , wherein said first conductive layer comprises a conductive portion and a non-conductive portion. 
   
   
       15 . The method of  claim 9 , wherein said second conductive layer is a silver based material. 
   
   
       16 . The method of  claim 9 , wherein said second conductive layer comprises a conductive portion and a non-conductive portion. 
   
   
       17 . The method of  claim 9 , comprising forming channels in said flexible support member, said channels permitting said first and third conductors and said first and second conductive layers to be in communication with one another. 
   
   
       18 . A method of forming a shielded flexible circuit, the method comprising:
 forming a first conductor and a second conductor from a first conductive material adhered to a first side of a flexible support member, said first and second conductors electrically insulated from one another;   forming a second conductive material co-axially disposed around said first conductor, said second conductive material electrically insulated from said first conductor;   forming a third conductive material co-axially disposed around said second conductor, said third conductive material electrically insulated from said second conductor.   
   
   
       19 . The method of  claim 18 , wherein forming said first and second conductors comprises etching copper traces. 
   
   
       20 . The method of  claim 18 , wherein said flexible support member is a polyimide film.