Patent attributes
A device for electrically stimulating biological material with an implantable electrode array placed in active contact with the biological material. The array has a two-dimensional arrangement of individual electrodes (Eij) that produce a stimulation field (S1, S2,) for the biological material when a stimulation signal is provided, and an apparatus for providing stimulation signals. Alternating field stimulation signals (Vij) are provided to the individual electrodes (Eij) and the electrode array has at least two tripolar or higher multipolar multipole elementary cells (T1, T2,; Q1, Q2,) from three or more adjacent individual electrodes each, and the stimulation fields (S1, S2,) produced by every multipole elementary cell for the biological material has a rotational component, and at least one of the individual electrodes pertains to at least two multipole elementary cells. Method of use, e.g. with retina implants are also provided.