Digital cameras tend to have two essential parts: a sensor and a lens. You can't do without the sensor, but researchers at Rice University have managed to skip the lens — resulting in a super-thin device they call the FlatCam.
The tiny camera is practically just a bare image sensor, but on top of the light-sensitive surface is a super-thin quartz plate with a special pattern of chrome printed on it. This pattern allows light through in such a way that a picture can be reconstructed from it — no lens necessary to get things into focus.
"The image formed on the sensor can be viewed as a superposition of many pinhole images," write the researchers in the paper describing FlatCam, available on Arxiv (PDF).
It's quite similar to another, even smaller camera built by Rambus in 2014; that one used an etched-glass surface on top of the sensor to split incoming light up predictably.
The resulting images in both cases are nothing any photographer would care to show off, but the point of these super-small cameras isn't quality, it's versatility.
"Moving from a cube design to just a surface without sacrificing performance opens up so many possibilities," said Richard Baraniuk, who led the project with colleague Ashok Veeraraghavan, in a Rice news release. "We can make curved cameras, or wallpaper that's actually a camera. You can have a camera on your credit card or a camera in an ultrathin tablet computer."
Right now FlatCam is just a prototype, but is built with off-the-shelf sensors and fairly easily created custom components. It's not out of the question to think we might see these appear in our electronics (or wallpaper) over the next few years. The research was funded by the National Science Foundation.