Micro-Stimulator Design For Optic Nerve Visual Prosthesis In Artificial Vision

According to the data from the World Health Organization for the year 2002 over 140 million people are visually impaired including 45 million blind. There are 5.5 million blind in China. The causes leading to blindness may be located at any stage(s) along the visual pathway within the central nervous system. And the neural electrical stimulation could be provided at various stages to restore the vision, i.e., cortical, optic nerve, sub-retinal, and epi-retinal visual prostheses. Each of the proposed approaches is expected to artificially generate visual sensations called phosphenes, which convey limited but crucial functional visual information.This paper presents an implanted multi-channel programmable micro-stimulator designed for stimulating electrodes in an optic nerve visual prosthetic device.Main contents of this paper include: theory of neural stimulation, analyse and design parameters for optic nerve stimulation which offer information for micro-stimulator design, and set up optic nerve stimulation model; programmable neuro-stimulator, which is the most important functional part of visual prosthesis, according to different methods, two approaches are suggested for micro-stimulator design, firstly, adopting analog integrated circuits, secondly, adopting discrete components, e.g., digital-analog converter, voltage-current converter, and analog switches.This micro-stimulator is capable of implementing the signal processing procedure from the digital signal mapping from the image captured by CMOS camera to the electrical stimulus delivering the efficient stimulation to the optic nerve, which could generate charge balanced biphasic current...