Polymer materials are useful as electrode array bodies for neural
stimulation. They are particularly useful for retinal stimulation to
create artificial vision, cochlear stimulation to create artificial
hearing, and cortical stimulation, and many related purposes. The
pressure applied against the retina, or other neural tissue, by an
electrode array is critical. Too little pressure causes increased
electrical resistance, along with electric field dispersion. Too much
pressure may block blood flow. Common flexible circuit fabrication
techniques generally require that a flexible circuit electrode array be
made flat. Since neural tissue is almost never flat, a flat array will
necessarily apply uneven pressure. Further, the edges of a flexible
circuit polymer array may be sharp and cut the delicate neural tissue. By
applying the right amount of heat to a completed array, a curve can be
induced. With a thermoplastic polymer it may be further advantageous to
repeatedly heat the flexible circuit in multiple molds, each with a
decreasing radius. Further, it is advantageous to add material along the
edges. It is further advantageous to provide a fold or twist in the
flexible circuit array. Additional material may be added inside and
outside the fold to promote a good seal with tissue.