Flexible circuit bearing a trackable low-frequency electromagnetic coil

A method to make a medical device, comprising:

• creating an electromagnet structure by winding a wire-like conductor into a coil around a core, the wire-like conductor having two opposing ends, wherein a first of the two opposing ends is arranged as a first lead of the coil and a second of the two opposing ends is arranged as a second lead of the coil;
• providing a flexible printed circuit structure having patterned therein a first metal trace and a second metal trace running linearly along a substantial length of a flexible substrate to form the flexible printed circuit structure, each of the first and second metal traces having a first end and a second end;
• electrically connecting the first lead of the coil to the first end of the first metal trace;
• electrically connecting the second lead of the coil to the first end of the second metal trace;
• and
• electrically connecting ancillary circuitry to the second end of the first metal trace and to the second end of the second metal trace, the ancillary circuitry positioned on the flexible printed circuit structure at an opposite end from the electromagnet structure.

A method of operating a medical device, comprising:

• passing a first portion of the medical device into a body of a patient while a second portion of the medical device remains outside the body of the patient;
• operating ancillary circuitry arranged at the second portion of the medical device to drive an excitation signal through a conductive coil of an electromagnet structure arranged at the first portion of the medical device, the excitation signal passed via first and second traces running substantially along a length of a flexible printed circuit, wherein the electromagnet structure includes a core and the conductive coil wound around the core, and wherein a first end of the conductive coil is electrically connected to a first end of the first trace and a second end of the conductive coil is electrically connected to a first end of the second trace;
• and
• sensing a magnetic field generated about the electromagnet structure by the excitation signal being driven through the conductive coil.

A method to make a plurality of medical devices, comprising:

• forming a plurality of electromagnet structures by winding a wire-like conductor into a respective coil around each respective core of a plurality of cores, the wire-like conductor of each respective coil having two opposing ends, wherein a first of the two opposing ends is arranged as a first lead of the respective coil and a second of the two opposing ends is arranged as a second lead of the respective coil;
• arranging the plurality of electromagnet structures on an assembly tray;
• forming an assembly panel of a plurality of flexible printed circuit structures, each respective flexible printed circuit structure of the plurality of flexible printed circuit structures having patterned therein a first metal trace and a second metal trace running linearly along a substantial length of a flexible substrate to form the respective flexible printed circuit structure, each of the first and second metal traces having a first end and a second end;
• for each corresponding pair of electromagnet structures of the plurality of electromagnet structures on the assembly tray and flexible printed circuit structure of the plurality of flexible printed circuit structures in the assembly panel:
• removing an electromagnet structure from the assembly tray and aligning the electromagnet structure with a corresponding flexible printed circuit structure with the first lead of the coil of the electromagnet structure positioned with the first end of the first metal trace of the corresponding flexible printed circuit structure and the second lead of the coil of the electromagnet structure positioned with the first end of the second metal trace of the corresponding flexible printed circuit structure;
• electrically connecting the first lead of the coil of the electromagnet structure to the first end of the first metal trace of the corresponding flexible printed circuit structure;
• electrically connecting the second lead of the coil of the electromagnet structure to the first end of the second metal trace of the corresponding flexible printed circuit structure;
• positioning corresponding ancillary circuitry on the corresponding flexible printed circuit structure at an opposite end from the electromagnet structure;
• and
• electrically connecting the corresponding ancillary circuitry to the second end of the first metal trace of the corresponding flexible printed circuit structure and to the second end of the second metal trace of the corresponding flexible printed circuit structure.

A system, comprising:

• a medical instrument having a first portion and a second portion with the first portion configured for insertion into a body of a patient, the medical instrument including:
• a flexible printed circuit having a length, the flexible printed circuit including:
• a first metal trace running substantially along the length of the flexible printed circuit, the first metal trace having a first end in the first portion of the medical instrument and a second end in the second portion of the medical instrument;
• a first contact pad electrically coupled to the first end of the first metal trace;
• a second metal trace running substantially along the length of the flexible printed circuit, the second metal trace having a first end in the first portion of the medical instrument and a second end in the second portion of the medical instrument;
• and
• a second contact pad electrically coupled to the first end of the second metal trace;
• an electromagnet structure in the first portion of the medical instrument, the electromagnet structure including:
• a core;
• a first lead contact electrically coupled to the first contact pad;
• a second lead contact electrically coupled to the second contact pad;
• and
• a conductive coil wound around the core with a first end of the conductive coil electrically coupled to the first lead contact and a second end of the conductive coil electrically coupled to the second lead contact;
• and
• ancillary circuitry arranged in the second portion of the medical instrument and electrically coupled to the second end of the first metal trace and to the second end of the second metal trace, the ancillary circuitry configured to drive an excitation signal through the conductive coil via the first and second metal traces to generate a magnetic field about the electromagnet structure.

A method to make a medical device, comprising:

• forming an electromagnet structure by winding a wire-like conductor around a core to form a first lead contact, a second lead contact, a conductive coil disposed between the first lead contact and the second lead contact, a first gap section disposed between the first lead contact and the conductive coil, and a second gap section disposed between the conductive coil and the second lead contact;
• forming a flexible printed circuit structure having a flexible substrate and patterned therein a first metal trace, a second metal trace, a first contact pad, and a second contact pad, the first and second metal traces having a first end and a second end and running linearly along a length of the flexible substrate, the first end of the first metal trace being electrically coupled to the first contact pad, and the first end of the second metal trace being electrically coupled to the second contact pad;
• aligning the electromagnet structure with the flexible printed circuit structure, the aligning including aligning first lead contact of the electromagnet structure with the first contact pad of the flexible printed circuit structure and aligning the second lead contact of the electromagnet structure with the second contact pad of the flexible printed circuit structure;
• electrically connecting the first lead contact of the electromagnet structure to the first contact pad of the flexible printed circuit structure;
• electrically connecting the second lead contact of the electromagnet structure to the second contact pad of the flexible printed circuit structure;
• positioning ancillary circuitry on the flexible printed circuit structure at an opposite end from the electromagnet structure;
• and
• electrically connecting the ancillary circuitry to the second end of the first metal trace of the flexible printed circuit structure and to the second end of the second metal trace of the flexible printed circuit structure.