CMOS-based flexible multi-site retinal stimulator toward retinal prosthesis technology

We developed a CMOS LSI stimulator chip for retinal prosthesis technology with features of (1) multi-site stimulation using an on-chip stimulator, (2) light-controlled (image-based) stimulation. The retinal stimulator was configured as an array of small-sized intelligent CMOS stimulators called a ldquounit chip.rdquo We can set different conditions for each unit chip connected to a single set of 5-channel bus wiring and perform multi-site, constant-current biphasic retinal stimulation. We implemented simple binary light-sensing circuitry on the unit chip to realize image-based patterned stimulation on the retina. We verified that all the implemented functionalities correctly work and characterized the performance of the circuitry. A demonstration for image-based patterned current injection using radially aligned unit chips was also performed.