Ultrathin Cameras Possible With ‘Folded’ Lens

Engineers at UC San Diego have developed new technology which could lead to lightweight, ultra-thin, high-resolution miniature cameras cell phones and other applications such as unmanned surveillance aircraft.

Researchers have built an ultrathin, powerful digital camera by ‘folding’ up the telephoto lens.

The revolutionary technique produces an imager about seven times more powerful than a conventional lens of the same depth.

The technique produces a miniature camera ideal for applications such as cell phones which require high resolution images and a short exposure time.

Although current cell phones produce good-quality wide angle shots, space constraints mean that the lens has a short focal length. This means that close up shots are blurry and dark.

The new ‘folded’ optical system allows camera thickness to be reduced without compromising light collection and high-resolution capabilities.

The new technique is based on an extension of conventional astronomical telescopes which employed mirrors, such as the Cassegrain telescope, which was developed in 1672.

Instead of using two mirrors, UC San Diego engineers cut all the reflective surfaces from a single component and quadrupled the number of folds.

Instead of bending and focusing light as it passes through a series of separate mirrors and lenses, the new folded system bends and focuses light while it is reflected back and forth inside a single 5 millimeter thick optical crystal.

The research, authored by Eric Tremblay and Joseph Ford, will be published in the February issue of the journal ‘Applied Optics’.