Retinal prosthesis device based on pulse-frequency-modulation vision chip

We describe a retinal prosthesis device that uses an image sensor based on a pulse frequency modulation (PFM) photosensor array. A PFM-based photosensor converts light intensity into the frequency of an output electrical pulse stream, and thus is suitable for stimulating retinal cells. We demonstrate various circuit improvements for image preprocessing and packaging techniques and present the results of an electrophysiology experiment.

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