Visual Prosthesis Based on Optic Nerve Stimulation with Penetrating Electrode Array - Artificial Sight: Basic Research, Biomedical Engineering, and Clinical Advances - page 203

skin

Implantable Neural Stimulator

Processing and
control
Power
management

Stimulus
driver

communication

power

Coding,
decoding,
transmission
and control

Filter and
commutate

Electrode
driver

D/A

Info
data

Electrodes
monitor

Figure 10.15. Schematic of the architecture of the micro-stimulator.

After the important characteristics of a visual object, such as position,
dimension, colour, etc., are extracted from the original image, we can encode
these information into special stimulation patterns.
The implantable micro-stimulator in our project consists of three parts:
communication unit, processing and control unit, and stimulus driver unit.
Figure 10.15 reveals the architecture of the micro-stimulator. The external
part collects the visual information and encodes the information into electrical
stimulation patterns. And then it modulates and transmits the patterns by radio
frequency (RF) telemetry with other important control signals. The implantable
parts exchange information by RF telemetry too. The transmission of power is
also realized by RF telemetry. Once the power and data information are received,
these information will be demodulated and decoded by the processing and control
unit, which also monitors and records the state of electrode arrays.
The Stimulus Driver Unit converts digital signals of stimulation patterns into
analog signals by DAC. The output of DAC is converted to biphasic current
pulses by stimulus driver circuitry and delivered to the penetrating electrode
array.

Implantable Micro-Camera in Model Eye

Design of Implantable Micro-Camera
This micro-camera which will be implanted in the position of the lens of the
blind eye consists of the micro-lens, CMOS and the cable. The raw data of the
image acquired by the micro-camera is then transmitted to the next processing
unit out of the eye through the cable.
According to the dimension of the normal human eye, the distance between
posterior cornea and crystalline lens is about 6mm, and the pupil size in