Vertical-junction photodiodes for smaller pixels in retinal prostheses

Objective.To restore central vision in patients with atrophic age-related macular degeneration, we replace the lost photoreceptors with photovoltaic pixels, which convert light into current and stimulate the secondary retinal neurons. Clinical trials demonstrated prosthetic acuity closely matching the sampling limit of the 100μm pixels, and hence smaller pixels are required for improving visual acuity. However, with smaller flat bipolar pixels,...