Abstract: Microelectrodes for use in stimulating and detecting activity in neurons of living organisms, and a method of manufacturing such microelectrodes. An electrically conductive electrode core member is sharpened and coated with a thin layer of a dielectric material. An extremely small area of the core at the sharpened point is exposed by ablating the dielectric material by the use of ultraviolet laser beam scanned over the material. Multiconductor microelectrodes include multiple fine wires which may be arranged in helical strands, optionally supported by a central core member of stiffer material. Multiple conductors may also be supported within a tubular support such as a hollow needle whose distal end is cut at a slant to expose the conductors, or in flat ribbon configuration with openings in dielectric material defining active electrode sites.

Abstract: A miniature, electrically-insulated multi-conductor electrical cable suitable for implantation in living bodies and readily connected to sensors or electrodes, and implantable microelectrodes attached to such cables. Individual electrical conductors are coated with at least one layer of, insulating material and stranded together, or optionally bound together by an additional layer of insulating material which is compatible with implantation in living bodies. The individual conductors are separated from one another in terminal portions of the cable and are held by a ribbonizing resin at a predetermined pitch to facilitate connection of each of the conductors. The terminal portions may define microelectrodes. Another microelectrode includes an electrically conductive electrode core member sharpened and coated with a thin layer of a dielectric material.

Abstract: A miniature, electrically-insulated multi-conductor electrical cable suitable for implantation in living bodies and readily connected to sensors or electrodes with terminal pads or to conductors such as printed flex circuit traces of electrical circuits, and a method for preparing such cables. Individual electrical conductors are coated with at least one layer of insulating material. The insulated individual conductors are stranded together, or optionally bound together by an additional layer of insulating material which is compatible with implantation in living bodies. The individual conductors are separated from one another in terminal portions of the cable and are encapsulated in a ribbonizing resin which is trimmed to expose portions of the individual conductors, held by the ribbonization resin at a predetermined pitch to facilitate connection of each of the conductors to a respective conductor trace of a printed circuit or flex circuit.

Abstract: A miniature controlled-impedance transmission line consists of a flexible cable having side-by-side conductors transmitting high frequency signals. The cable is preferably in the form of a pair of conductors, each surrounded by respective inner and outer dielectric layers of different compositions. The inner and outer dielectric layers are applied to each conductor independently of the other conductor, after which the respective outer dielectric layers of the two conductors are bonded together in side-by-side relationship without altering the inner dielectric layers. The result is a conductor pair having minimum cross-section for high-density applications and uniform capacitance which is also stable in that it will not change with subsequent bending or handling.

Abstract: A yieldably extensible, self-retracting cable comprises a flexible center conductor surrounded by a primary dielectric material with a flexible wire shield exterior thereof and a thermoplastic or thermosetting elastomeric outer jacket formed permanently in a helical shape. The primary dielectric insulation comprises materials such as polymeric fluorocarbon or irradiated polyethylene having an exceptionally low dielectric constant. The low dielectric constant is maintained despite the permanently coiled configuration of the cable by ensuring that the plasticizing or curing temperature of the jacket is less than the melting or other degradation temperature of the dielectric material, and by utilizing unbraided wire shielding comprising a pair of concentric layers of wire wound helically in mutually-opposite directions to avoid mechanical injury of the dielectric material.