The researchers deposited layers of metal just a few nanometers thick in a circuit pattern. They also created tiny, round openings on the surface meant eventually to hold nanometer-sized light-emitting diodes. Next, they sprinkled the light-emitting diodes onto the surface. The LEDs are so tiny that they resembled a powder. Like marbles inside a pinball machine, the LED particles roll around until coming to rest inside one of the openings. The researchers then coated the whole device with a harmless material and shaped it to fit the curve of an eye. The lenses were tested on rabbits for up to 20 minutes, and the animals showed no adverse effects. Because of concerns for animal safety, the scientists did not light up the LEDs for display, but they plan to perform this test as soon as they are confident it will be safe. The idea is that the LEDs will create an image on the back of the retina, which the wearer sees overlaid onto their natural view of the world. Or in another application, sensors on the contact lens could be designed to send a signal when they detect a particular molecule. Recently, the researchers demonstrated that they could power the lens using radio signals. These signals would eliminate the need for any embedded power supply, such as batteries that could contain chemicals harmful to the eye. But those signals might not be enough, said George Malliaras, associate professor of materials science and engineering and director of the Cornell NanoScale Science and Technology Facility at Cornell University in Ithaca, NY. "If you use it as a display or as a GPS, you need a computer on the side," said Malliaras. "That will involve a lot of data being transferred, and will take a considerable amount of real estate to deal with this data." But, said Malliaras, "the demonstration shows how promising it is and is a big step toward many more impressive things to come." Related Links: |
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