Fabrication and characterization of a wireless retinal implant on flexible substrates Fertigung und Charakterisierung eines drahtlosen Retina-Implantats auf flexiblen Substraten

We present the fabrication and characterization of demonstrators of a flexible epiretinal prosthesis for the treatment of retinitis pigmentosa. The prosthesis comprises of a wireless miniaturized electronic system that generates electrostimulation signals from energy and information received optically. The combination of a flexible substrate foil made of polyimide with a mosaic-like array of thinned silicon-based photodiodes enables the production of implants that adapt to the curvature of the eye. The developed manufacturing concept combines the fabrication of silicon photodiodes in bipolar technology with additional manufacturing steps for further microtechnological processing of a pre-structured silicon wafer to obtain flexible substrates with photodiodes in the end. The implants manufactured in this way were tested in a measurement chamber with regard to the potential curve upon exposure to an infrared laser.