A Stanford University research team is using photovoltaic chip implants to give blind people that suffer from degradation in their photoreceptor cells partial vision. So far, the major problem with artificial implants has been how to pass power and image data to a processing retinal chip implanted at the back of the eye, and onward to the brain.
The Stanford device does both, generating power and passing data and works by using a miniature solar cell array in the eye. It is called a sub-retinal implant as it is placed behind the retina, and it generates power and passes the image data across the eyeball for the brain to process.
The system includes a video camera to capture the image, a pocket PC to process the image real time, and a bright near-infrared LCD screen. The LCD screen produces enough light to enter the eye and charge-up the solar cell array.
The tiny 3mm (0.118”) wide chip has 3 layers and is only 0.03mm (about 1 thou) thick. Each layer has 3 photovoltaic cells of three different sizes and is flexibly mounted on the retina using minute 300 nanometre (0.0003mm) thick silicon posts.
The photovoltaic system gives vision of 20/100, which is enough to recognize faces and read large print.
Visit: IEEE Spectrum
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