Materials scientists working in the U.S. say they’ve designed an electronic camera that can mimic the shape of the human eye. The design is a big step in imaging as it could lead to bionic implants and sensors in humans.
Digital Journal — In the Aug. 7 issue of the journal Nature, John Rogers, a materials scientist at the University of Illinois at Urbana-Champaign, and his colleagues are publishing findings of a new experiment where the team created a working curved camera.
The eye-shaped camera is made from a flexible mesh of silicon light-detectors and it is a big step in the goal to create a bionic eye.
As Nature explains:
Conventional cameras use a curved lens to focus an image onto a flat surface where the light is captured either by film or by digital sensors. However, focusing light from a curved lens onto a flat surface distorts the image, necessitating a series of other lenses that reduce the distortion but tend to increase the bulk and cost of a device.
The human eye uses a single lens, and does not get the same level of distortion commonly found in cameras because an image is focused on a curved surface at the back of the eye, Nature says.
For decades, scientists have wanted to create a curved camera that would work properly, but electronic materials have not been flexible enough and would snap if bent.
Rogers and his team say they’ve developed a way to have a flat sensor adhere to a curved shape, similar to surface of the back of a human eye.
The team used silicon photodetectors (pixels) connected by thin metal wires, supported by a thin film of polyimide plastic that allows the device to bend instead of break. The “scaffold,” Nature reports, “takes up the mechanical stress and protects the pixels as the array takes its hemispherical shape.”
In plain English: Traditional camera makers use multiple lens arrangements to avoid distortion around edges of flat lenses, but they are too big to be practical in smaller applications, according to the CBC. Rogers and his team avoided this issue by building an array of photo sensors that are connected by wires and each sensor (pixel) is incredibly small (0.56 millimetres by 0.56 millimetres). The result is a sensor that can bend into a curved shape.
“The ability to wrap high quality silicon devices onto complex surfaces and biological tissues adds very interesting and powerful capabilities to electronic and optoelectronic device design,” said Rogers. “It allows us to put electronics in places where we couldn’t before.”
Rogers and his team have also gone a step further in improving the camera resolution; mimicking the continuous movement of a human eye, the team took many images with their camera at different angles and combine them with a computer to get a sharper image.
The technology could later be adapted to be used in bionic implants, robotic sensory skins and biomedical monitoring devices. Currently, the camera is limited to 256 pixels but Rogers says this can be scaled up.
According to Nature, Dago de Leeuw, a research fellow with Philips Research Laboratories based in Eindhoven in the Netherlands, described this research as “breakthrough.”
“We believe that some of the most compelling areas of future application involve the intimate, conformal integration of electronics with the human body, in ways that are inconceivable using established technologies,” said Rogers. “This approach allows us to put electronics in places where we couldn’t before. We can now, for the first time, move device design beyond the flatland constraints of conventional systems.”
In March of 2008, DigitalJournal.com covered a report about scientists at Standford University who were working on another camera-related project, where 12,616 lenses were combined to create depth-maps in photography.
