Novel Retinal Prosthesis System with Three Dimensionally Stacked LSI Chip

We have proposed a novel retinal prosthesis system with three-dimensionally stacked retinal prosthesis chip. The retinal prosthesis chip consists of several LSI chips that are vertically stacked and electrically connected using three-dimensional integration technology. We fabricated retinal prosthesis chip including photodetectors and stimulus current generators. We confirmed that current waveform parameters can be varied by bias voltages. Implantable stimulus electrode array was also fabricated for the electrical stimulation of the retina. To evaluate optimal retinal stimulus current, electrically evoked potential (EEP) was recorded in animal experiments. The recorded waveform shows a similar behavior to the visually evoked potential (VEP) waveform, indicating possibilities that the electrical stimulation of the retina can restore visual sensation for the blind patients.