Researchers at the University of Michigan came up with a tiny camera solution that captures up to 15 frames per second. The camera is under a millimeter wide and is powered by light, a self-powered and microscopic tool.
The team engineered a prototype sensor that is essentially almost invisible that operates with no battery or wireless power. While the construction of the imager leverages CMOS process technology, the pixels are of a different structure than those on a typical imager. With an extra diode–a p-n junction—under the diode that senses the image, energy is able to be captured.
Euisik Yoon, a professor of electrical engineering and computer science led the research, along with postdoctoral researcher Sun-Yun Park. Earlier attempts had drawbacks of too-little light being captured due to photovoltaics taking up space, or too-complex due to alternating the use of the imager between the photodetector and photovoltaic cell. The solution the team came up with avoided both drawbacks by burying a second diode beneath the photodetector to act as a photovoltaic, catching stray photons that pass the first diode. “It’s not really recycling; it’s more like collecting waste,” comments Yoon. “It’s almost free energy.”
Learn more about this project here.