Helical core ear implant electrode

1. An intracochlear electrode array configured to be implanted within the cochlea of an implanted patient, the electrode array comprising:

an electrode array core comprising a plurality of thin-film layers of a flexible polymer material, the electrode array core having an apical end and a base end and including:

i. a first portion towards the apical end having an elongated helical shape with the plurality of thin-film layers configured to form a plurality of helical turns without residual stress, and

ii. a second portion towards the base end configured to have a straight planar shape;

a plurality of electrode wires embedded within the array core for carrying electrical stimulation signals;

at a terminal end of each electrode wire, an electrode stimulation contact exposed through the array core for applying the electrical stimulation signals to adjacent neural tissue; and

an electrode carrier of resilient material encasing the electrode array and having an outer surface with a plurality of contact openings exposing the stimulation contacts;

wherein the material of the electrode carrier and the helical turns of the first portion of the electrode array core are configured to cooperate to provide flexibility for lateral bending during insertion of the electrode array into the cochlea of the implanted patient; and

wherein he material of the electrode array and the straight planar shape of the second portion of the electrode array core are configured to cooperate to provide rigidity that requires increased lateral bending force for handling by a surgeon implanting the electrode array into the cochlea of the implanted patient.

2. An implantable electrode array according to claim 1 , wherein the helical portion of the array core contains a plurality of smaller recurring waveform shapes in every helical turn in the first portion of the electrode array core.

3. An implantable electrode array according to claim 1 , wherein every helical turn in the first portion of the electrode array core has a stimulation contact.

4. An implantable electrode array according to claim 1 , wherein not every helical turn in the first portion of the electrode array core has a stimulation contact.

5. An implantable electrode array according to claim 4 , wherein every second helical turn in the first portion of the electrode array core has a stimulation contact.

6. An implantable electrode array according to claim 1 , wherein the electrode array has a constant distance between helical turns in the first portion of the electrode array core.

7. An implantable electrode array according to claim 1 , wherein the electrode array has a variable distance between helical turns in the first portion of the electrode array core.

8. An implantable electrode array according to claim 1 , wherein the helical shape has a constant diameter.

9. An implantable electrode array according to claim 1 , wherein the helical shape has a diameter that decreases towards one end.

10. An implantable electrode array according to claim 1 , wherein each stimulation contact is split into a plurality of contact sections electrically connected by a plurality of connecting sections.

11. An implantable electrode array according to claim 1 , wherein the stimulation contacts are formed on contact wings perpendicular to the electrode wires.

12. An implantable electrode array according to claim 11 , wherein the contact wings are supported by the array core.