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, or cortical stimulation many 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.