The one cent coin is slightly smaller than a British 1 penny coin, so this is a very tiny little power chip. A bona fide ocular implant should be able to power itself. An implant without that capability would necessitate surgery to replace batteries or have a wire emerge from the eye to supply electricity. A tiny solar panel solves the problem of supplying energy. Jim Mann, Terry Hernden and Tony Soares at MIT-Lincoln Labs were instrumental in the design, fabrication and testing of the solar panel.
Light striking the panel causes ionization which produces charged ion pairs or current.
Voltage depends on the light's wavelength and intensity. Using near infrared wavelengths at intensities believed to be safe for the eye, the photodiode array delivers approximately seven volts, slightly more than needed to power the circuit chip that will transfer the visual signal to the retina. Both the solar panel and circuit chip will be contained within a capsule. The solar panel measures 2 by 2 millimeters and consists of 12 photodiodes made of silicon connected in series. I wish them and their future patients very good luck with it.