초록 ▼

An implant device uses tantalum and tantalum pentoxide as a complete system for the conveyance of electrical stimulation pulses from stimulus-forming circuitry contained within an hermetic enclosure to the saline fluids of the cochlea (or other tissue to be stimulated). Internal coupling capacitors

An implant device uses tantalum and tantalum pentoxide as a complete system for the conveyance of electrical stimulation pulses from stimulus-forming circuitry contained within an hermetic enclosure to the saline fluids of the cochlea (or other tissue to be stimulated). Internal coupling capacitors are not used, yet the danger of having DC current flow to the saline fluids is eliminated. A preferred embodiment is a cochlear prosthesis comprised of a multiplicity of electrode contacts made from sintered, anodized tantalum, connected via tantalum wire leads to tantalum feedthroughs into the hermetically sealed package containing the stimulus pulse-forming electronic circuitry. One or more counterelectrode contacts (for monopolar or bipolar configurations, respectively) consist of activated iridium, connected via platinum or other noble metal leads to noble metal feedthroughs. When powered-up, the stimulus generating circuit produces a steady polarizing potential of approximately half its maximum output voltage range, which potential is applied as a positive (anodizing) voltage to each tantalum electrode and associated lead and feedthrough, with respect to the activated iridium electrode(s), which act as the reference point for the circuit.

대표청구항 ▼

[ What is claimed is:] [1.] An implantable tissue-stimulating prosthesis comprisingimplantable stimulus-forming electronic circuitry hermetically sealed in a package, said package comprising a tantalum feedthrough which provides an electrical path to the stimulus-forming circuitry hermetically seale

[ What is claimed is:] [1.] An implantable tissue-stimulating prosthesis comprisingimplantable stimulus-forming electronic circuitry hermetically sealed in a package, said package comprising a tantalum feedthrough which provides an electrical path to the stimulus-forming circuitry hermetically sealed within said package, and a noble metal feedthrough that provides a return electrical path to the stimulus-forming circuitry hermetically sealed within said package;at least one electrode contact made from sintered, anodized tantalum;at least one tantalum wire lead connecting a respective at least one electrode contact to the tantalum feedthrough, whereby the electrode contact is electrically connected to the tantalum feedthrough, and hence to the stimulus-forming electronic circuitry;a layer of tantalum pentoxide covering said tantalum electrode contact and at least those portions of said tantalum wire lead that are exposed to body fluids;a counterelectrode contact made from activated iridium; anda noble metal lead connecting the counterelectrode to the noble metal feedthrough;wherein the implanted stimulus-forming electronic circuitry comprisesmeans for deriving a source of operating potential V.sub.s,means for maintaining an anodic voltage +Vp between the tantalum feedthrough and the noble metal feedthrough, with the tantalum feedthrough being positive relative to the noble metal feedthrough, the anodic voltage +Vp being no greater than about 1/2 of the operating potential V.sub.s, andmeans for varying the voltage that is applied between the tantalum feedthrough and the noble metal feedthrough by an amount .+-..increment. so as to cause a balanced biphasic current pulse to flow between the tantalum electrode and the iridium counterelectrode.