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Design and realization of a simulator of prosthetic vision and inkjet printing of platinum nanoparticles on a ceramic substrate. by Michael Foerster Supervisor at UNSW: Professor Nigel H. Lovell Supervisor at ECL: Professor Ségolène Callard 12 th of September 2008. The human visual system.
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Design and realization of a simulator of prosthetic visionandinkjet printing of platinum nanoparticles on a ceramic substrate by Michael Foerster Supervisor at UNSW: Professor Nigel H. Lovell Supervisor at ECL: Professor Ségolène Callard 12th of September 2008
The human visual system / 24 2
A retinal prosthesis Camera Image processor RF-transmitter Implanted ASIC Electrode array / 24 3
My projects 2 studies: - Development of a tool for psychophysics studies. - Investigation of an alternative fabrication method for the printed circuit board (PCB) of the prosthesis. 10 mm / 24 4
Simulated Prosthetic Vision What can you see with a prosthesis ? How to improve prosthetic vision ? / 24 5
The need of a simulator Understand prosthetic vision Measure scanning patterns Test hardware choices Test image processing algorithms Use for demonstrations / 24 7
Specifications adjustable phosphene number adjustable number of grey levels different modulations (size, intensity, both) different shapes (circles, gaussians) different sampling methods possible overlapping of phosphenes user friendly interface use of camera, eye tracker and head mounted display / 24 8
Global organization of the SPV: Interaction of these boxes via Simulink Structure of the SPV / 24 9
Conclusion Results: Simulator is ready to be used for experiments Has already been used for demonstrations Experiments should be made soon by another student Future developments: increase of frame rate increase of portability / 24 12
Inkjet printing of platinum tracks An alternative fabrication method… / 24 13
Ceramic-Platinum PCB’s / 24 14
Specifications Specifications of the printed tracks: Maximum track width/clearance: 200/200μm Continuity of printed tracks Repeatable printing Printable surface: 3 x 3cm / 24 15
Inkjet technology Piezoelectric inkjet printer:a piezoelectric element induces a change of volume in a cavity and produces the drop emission Each nozzle can be activated separately Drop emission is coordinated with substrate displacement / 24
Design choices • Ink: diluted platinum paste used for screen printing(ethanol, texanol and platinum paste) • Print head • Driving voltage • X-Y displacement • Coordination • Data conversion / 24
Use of a desktop printer Both pressure waves have to be coordinated Existence of a jetting diagram / 24 18
Design choices • Ink: diluted platinum paste used for screen printing(ethanol, texanol and platinum paste) • Print head • Driving voltage • X-Y displacement • Coordination • Data conversion / 24
The X-Y displacement • Coordination through Matlab / 24 Autoscan AS3000i XYZ stageresolution: 250nmrange: 75 x 50 mm 20
The print head MicroFab ABP-30: • Nozzle diameter: 30 µm • Minimum drop diameter: 20 µm • Trapezoidal voltage waveform / 24 21
Driving the print head / 24 Mono- and biphasic waveforms Adjustable slope and dwell time:5-150µs Adjustable amplitude: -90V to +90V Remotely triggered 22
Entire printing station / 24 23
Future of the project / 24 Assemble parts together Write interface programs Test Find optimum parameters 24