it is a project based on ARM , incudes ADC, Sensors,LCD etc.

1. WELCOME

2. Prepared by
Kavita Bansal
U.Roll no. : 12EUCEC027
8th Semester (ECE)-2016 batch
University college of engineering, RTU , KOTA
SEMINAR ON
ARTIFICIAL RETINA
USING THIN FILM
TRANSISTOR
TECHNOLOGY

3. INDEX
 Introduction
 Disease related to eye
 Retinal implantation
 Epiretinal artificial devices
 Subretinal artificial devices
 Working operation
 Wireless power supply using inductive coupling
 Components
 Working
 Detected result of illumination profile
 Demerits
 Current status and future
 Conclusion
 Reference

4. INTRODUCTION
• The Artificial Retina made using Thin-Film Transistors, which can
be fabricated on transparent and flexible substrates.
• Electronic photo devices and circuits are integrated on the artificial
retina.
• Implanted on the inside surface of the living retina at the back part
of the human eyeballs. Moreover, since the human eyeballs are
curved, the flexible substrate is also preferable.
• Wireless power supply is used

5. DISEASE RELATED TO EYE
Age-related macular degeneration (AMD)

6. CONTINUED…..
Four stages of Retinal Pigmentosa

7. RETINAL IMPLANTATION
• A retinal implant is a biomedical implant technology
• The first application of an implantable stimulator for
vision restoration was developed by Drs. Brindley and
Lewin in 1968.
• There are two types of retinal implants namely
epiretinal implant and subretinal implant.

8. Retinal implant
• Electrode implantation is one
of the most critical jobs in this
artificial vision system
• The first step done in this
electrode implantation is
perforating a platinum foil with
each hole having a diameter of
3mm
• 68 flat platinum electrodes of
1mm diameter are pierced
through the holes into the
nucleus of neurons of the
occipital lobe

9. Continued…….
• Each electrode is connected by separate Teflon
insulated wire to a connector contained in the
pedestal
• The group of wires pass the electrical impulses
which are generated by the processor
• When the electrode is stimulated by the processor
by sending an electrical impulse, the electrode
produces closely spaced phosphene (light spots
seen by visual field)
• By sending the electrical impulses in different
combinations and permutations the phosphene can
be created in a regular fashion describing the image
ECE Dept. M.I.T. Manipur
12

11. RETINAL IMPLANT LOCATION:
SUBRETINAL VS. EPIRETINAL

12. EPIRETINAL IMPLANT
 Implanted on the surface of the retina
 The implant converts externally captured data to a
sequence of electrical stimuli
 Stimulates ganglia leading to optic nerve activation

14.  Advantages:-
 Minimizes the amount of microelectronics implanted and
upgrades are easy to do on the wearable portion thus
avoiding future surgery
 Heat can be dissipated into the vitreous humor
 External control over image processing allowing for
customizability, possible better clarity
 Disadvantages:-
 Difficulty attaching the implant to the fragile inner retina
 Complicated processing.

15. EPIRETINAL ARTIFICIAL DEVICES
 Artificial Retina Component Chip (ARCC)
 2 mm by 20 microns
 Placed on retinal surface
 Secondary device attached to a pair of common
eyeglasses directs a laser at the chip's solar
cells to provide power
 Requires small battery pack

16. THE ARCC DEVICE
 ARCC is powered by an external laser aimed at a
photovoltaic cell implanted on the back of the eye
 The laser is mounted on glasses that must be worn
for the chip to function
 The photosensors on the chip convert the light and
images into nerve impulses, much like the normal
human retina

17. THE ARCC DEVICE
 This system is, in essence, a video camera which views
an image, sends the information of the pattern of light in
the image by laser to the photovoltaic cell, which then
stimulates the ganglia of the optical nerve to recreate a
partial image
 Image is a rough pattern of light and dark areas that
provides clues on the shape and size of objects being
viewed
 The electrodes do not pass current to stimulate the
ganglia directly. Instead, the electrodes charge a plate
that then stimulates the ganglia. This step is intended to
reduce the risk of damage to the retinal tissue from the
electrical current

18. THE ARCC DEVICE

19. SUBRETINAL
 A microphotodiode array is placed between the
inner and outer layers of the retina, between the
bipolar cell layer and the retinal pigment epithelium
 Concept is to directly replace native photoreceptors
with artificial silicon-based photodiodes

20. SUBRETINAL
 Advantages
 Utilizes the surviving bipolar cells – the next step in the
pathway –Retinal processing can take place
 Placing the microphotodiodes between layers on the retina
will allow for it to be held in position next to functioning
cells
 Proximity with existing neurons requires less current and
leads to better resolution
 Disadvantages:
 Limited space
 Heat damage due to proximity of device to retinal cells
 Ambient light may not be adequate to generate current in
this array

21. SUBRETINAL ARTIFICIAL DEVICES
 Artificial Silicon Retina (ASR) by
Optiobionics
 2mm by 25 microns (thinner than a human hair)
 3,500 solar cells that convert light into electrical
pulses
 Implanted in the subretinal space
 Powered by ambient light

22. THE ASR DEVICE
 The ASR Device
Placement of the ASR Device in the
subretinal space

23. THE ASR DEVICE
 The ASR device works by producing visual signals
similar to those produced by the photoreceptor
layer
 These artificial “photoelectric” signals from the ASR
microchip induce biological visual signals in the
remaining functional retinal cells which may be
processed and sent via the optic nerve to the brain
 The microchip is designed to interface and function
with a retina that has partial outer retinal
degeneration

24. WORKING OPERATION
• It uses the same fabrication processes as conventional
poly-Si TFTs and encapsulated using SiO2
• The retina array includes matrix-like multiple retina
pixels
• The retina pixel consists of a photo transistor, current
mirror, and load resistance.
• The photosensitivity of the reverse-biased p/i/n poly-Si
phototransistor is 150 pA at 1000 lx for white light.
• The retina pixels irradiated with bright light output a
higher Vout, whereas the retina pixels irradiated with
darker light output a lower Vout.

25. DIAGRAM

27. FABRICATION OF THIN FILM
PHOTOTRANSISTORS
• Low temperature poly-Si TFTs have been developed in
order to fabricate active matrix LCDs with integrated
drivers on large glass substrates.
• For integrated drivers, CMOS configurations are
necessary.
• Ion implantation is one of the key factors in fabricating

29. ION DOPING TECHNIQUE
• The new I/D system which is one of the non mass
separated implanters. 5 percent Phosphane (PH3) or 5
percent Diborane (B2H6) diluted by hydrogen is used for
the doping gas
• Main features of this system are:
1) A large beam area
(over 300 mm square)
2) A high accelerating voltage
(maximum: 110 KeV)

30. WIRELESS POWER SUPPLY USING INDUCTIVE
COUPLING
 For implanted electrical power to function, either an im-
planted battery or via wireless power transmission used.
 For proper retinal functioning, continuous power
transmission is required.
 Inefficient transmission of power is a performance
limiting factor.
 High density electrode array with more than 1000
electrodes will consume about 45 mW of power.

31. CONTINUOUS…
• Chip-25mw
• Neuronal stimulation-20mw
• Based on 64 simultaneously operating electrodes each
requiring a maximum of 0.3 mW at 60 Hz image refresh
rate.

33. DISADVANTAGES OF POWER TRANSMISSION
• Difficulty in placing a large receive coil inside the eye.
• We face are large separation between the coils
• Reduction in power transfer to the device.
Overcome problems:
• Intermediate link between
the primary and secondary coil
• Which are embedded under
the wall of the eye

34. Component
Digital camera
Video-
processing
unit
Radio
transmitter
Radio
receiver
Retinal
implant
ECE Dept. M.I.T. Manipur
8

35. WORKING

36. WORKING DIAGRAM
Video Camera
Video
processing
unit
Receiver
Retinal ImplantNeuronsBrains
ECE Dept. M.I.T. Manipur
14

37. DETECTED RESULT OF ILLUMINATION PROFILE

38. DEMERITS
Surgery is required to implant
the electrode array.
Repairing is difficult if any of
the devices got damaged.
Those who lost their visions due
to other reasons could not use
this device.
The approximated cost of the
device is $70,000

39. CURRENT STATUS AND FUTURE SCOPE

40. CONCLUSION
Revolutionary piece of
technology.
Good news for AMD and
retinal pigmentosa patients

41. REFERENCES
 www.howstuffworks.com
 Chandu Gude,"Bionic Eye", Scribd, 2009.
 www.wikipedia.org
 www.sciencedaily.com
 www.electrooptic.com

42. THANK YOU