Method for producing a miniature electromagnetic coil using flexible printed circuitry

Abstract

An elongate medical device includes a sensor configured to detect one or more characteristics of an electromagnetic field in which the device is disposed. The sensor includes an electrically-insulative substrate, rectangular in shape, and a patterned, conductive trace disposed on the substrate. The patterned trace includes a plurality of diagonal sections parallel to one another, arranged with a relatively low pitch. The substrate is wrapped into a cylindrical shape thereby forming a three-dimensional spiral capable of functioning as a micro-electromagnetic sensor. A medical positioning system is responsive to the signal from the sensor to determine a position and/or orientation of the sensor.

1 .- 20 . (canceled) 
     
     
         21 . An elongate medical device having a body with proximal and distal end portions, comprising:
 an electrically insulative, flexible substrate in a three-dimensional form and having a non-flat, curved surface;   an electrically-conductive trace disposed on said substrate in a pattern, said trace comprising start and end leads, said pattern of said trace comprising at least one of a straight pattern and a spiral pattern, said trace being configured to be electrically connected to an electrical conductor configured to extend through said elongate medical device to said proximal end portion thereof.   
     
     
         22 . The medical device of  claim 21  wherein said substrate is cylindrical and said trace is configured to form a plurality of turns between said start and end leads configured to detect a characteristic of an electromagnetic field and produce a signal indicative of said characteristic to define a sensor, said start lead being at a proximal end of said sensor, said end lead returning from a distal end of said sensor to said proximal end of said sensor and being electrically insulated with respect to said trace such that both of said leads appear at said proximal end of said sensor. 
     
     
         23 . The medical device of  claim 21  wherein said plurality of turns define a plurality of trace sections and wherein a spacing between the trace sections is less than a width of one of said plurality of trace sections of said trace taken into a longitudinal direction and constant across the trace. 
     
     
         24 . The medical device of  claim 22  wherein said electrical conductor is a first electrical conductor further comprising a second electrical conductor, wherein said first and second electrical conductors comprise a cable, said first and second electrical conductors being coupled to said start and end leads. 
     
     
         25 . The medical device of  claim 24  wherein said cable is configured for electrical connection to a positioning system. 
     
     
         26 . The medical device of  claim 21  wherein said substrate comprises a flexible printed circuit board (PCB). 
     
     
         27 . The medical device of  claim 21  wherein said substrate comprises a flexible plastic material selected from the group comprising polyimide, polyetheretherketone (PEEK), polyester, polyethylene terephthalate and a combination thereof. 
     
     
         28 . The medical device of  claim 21  wherein at least a portion of said electrically-conductive trace is disposed on said substrate in a serpentine pattern including advancing and returning sections with intervening bend sections. 
     
     
         29 . The medical device of  claim 28  wherein said serpentine pattern is configured such that said advancing and returning sections are angled with respect to a longitudinal axis of said sensor. 
     
     
         30 . The medical device of  claim 28  wherein said advancing and returning sections are parallel. 
     
     
         31 . The medical device of  claim 21  wherein said substrate includes a plurality of layers, wherein at least a portion of said plurality of layers contains said electrically- conductive trace. 
     
     
         32 . The medical device of  claim 31  wherein at least one of said layers comprises ferromagnetic material configured to increase sensing sensitivity. 
     
     
         33 . The medical device of  claim 21  wherein said trace comprises an electrically-conductive material selected from the group comprising copper, platinum, gold, or a combination thereof. 
     
     
         34 . A method of fabricating an elongate medical device, comprising the steps of:
 providing an electrically-insulative, flexible substrate in a three-dimensional form and having a non-flat, curved surface; and   producing an electrically-conductive trace on said substrate in a pattern, said trace comprising start and end leads, said pattern of said trace comprising at least one of a straight pattern and a spiral pattern, said trace being configured to be electrically connected to an electrical conductor configured to extend through said elongate medical device to said proximal end portion thereof.   
     
     
         35 . The method of  claim 34  wherein providing said substrate comprises providing a flexible printed circuit board (PCB). 
     
     
         36 . The method of  claim 34  wherein providing said substrate comprises selecting, for said substrate, a flexible plastic material from the group comprising polyimide, polyetheretherketone (PEEK), polyester, polyethylene terephthalate and a combination thereof. 
     
     
         37 . The method of  claim 34  wherein said substrate is provided with a plurality of layers, wherein each of said plurality of layers contains said electrically-conductive traces. 
     
     
         38 . The method of  claim 34  wherein said substrate and trace are configured so as to form a plurality of turns between said start and end leads configured to detect a characteristic of an electromagnetic field and produce a signal indicative of said characteristic to define a sensor. 
     
     
         39 . The method of  claim 38  wherein said start lead is at a proximal end of said sensor, said end lead returning from a distal end of said sensor to said proximal end of said sensor and being electrically insulated with respect to said trace such that both of said leads appear at said proximal end of said sensor. 
     
     
         40 . The method of  claim 34  wherein producing said trace comprises selecting an electrically-conductive material for said trace from the group comprising copper, platinum, gold, or a combination thereof.