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The multitude of lenses that make up an insect’s eye is providing inspiration for a new generation of super-slim camera phone.

Conventional camera lenses cannot be shrunk below a few millimetres in thickness before reducing the field of view. But a compound lens, made from hundreds of tiny “micro lenses”, can be made around one-tenth of the width, while retaining the same field of view and quality of image.

A prototype compound eye, consisting of scores of polymer micro-lenses has now been developed by researchers at the Fraunhofer Institute for Applied Optics and Precision Engineering in Germany, Swiss company SUSS MicroOptics and the University of Neuchâtel in Switzerland.

The 2-millimetre-thick prototype has 21 light-channelling components, each of which contains three separate lenses. Each individual lens points in a slightly different direction and projects part of the image on to a photo sensor. “Each channel is, in effect, a pinhole camera,” says Andreas Bräuer at the Fraunhofer Institute.

Different directions

Bräuer told New ¾«¶«´«Ã½ that in theory it should be possible to make compound lenses just a few hundred micrometres in thickness. This could make it possible to install a camera into a smart card that could then perform simple image recognition tasks, he says.

The image quality of such a small compound lens would be limited to about 250 by 250 pixels, or 0.06 of a megapixel. The lenses should be relatively cheap and simple to manufacture, as micro lenses can be made using existing lithographic techniques, Bräuer adds.

Jim Girkin, at the University of Strathclyde in Glasgow, UK, says micro lenses would be best suited to applications that require only low quality, because they are naturally prone to distortion. “If they can be made reliably and cheaply, then for certain applications they could prove very interesting,” he says.

Nick Jones, a mobile phone expert at analyst firm Gartner, UK, says size of a cell phone camera depends primarily on the mechanism used to focus and zoom. But he says a smaller lens could perhaps be integrated with an optical sensor to make a cheaper overall camera system.

Journal Reference: Optics Express (Vol 13, p 889)