Electrical stimulus experiments of the frog retina using a pulse frequency modulation image sensor for retinal prosthesis

We have designed and fabricated a 16 × 16 pixel pulse frequency modulation (PFM) image sensor for retinal prosthesis. This sensor is a prototype for demonstrating application in in vitro electrophysiological experiments. Each pixel has a bonding pad on which a stimulus electrode is formed by a Pt/Au stacked biocompatible bump electrode. We have evaluated the PFM image sensor for retinal prosthesis by in vitro electrophysiological experiments using the detached frog retina, and confirmed that it can electrically stimulate the retinal cells effectively.