Electrodes designed in accordance with the present invention may selectively employ arc shaped contacts; variations in contact number, positioning, spacing, and/or distribution; variations in contact area, size, or periphery; and/or on-electrode conductive links or interconnections between particular...http://www.google.de/patents/US8126568?utm_source=gb-gplus-sharePatent US8126568 - Electrode geometries for efficient neural stimulation
