Ultrathin Lens Could Lead to Cheaper Surveillance Cameras

May-26-14 Researchers have discovered a technique that could allow night-vision camera lenses to be made from silicon, significantly decreasing the cost of the cameras.

Silicon normally cannot be used for thermal infrared cameras because the material absorbs too much light. However, a team of French researchers have proven that by cutting the material very thin they were able to get around that limitation. To build the thinner lens, the team laser-etched a Fresnel-style silicon lens, which is made up of a series of concentric rings. By increasing the depth of the rings while also decreasing their number, the team was able to create a lens only 1 mm thick and 4 mm in diameter that delivered a 130-degree field of view of reasonable quality.

The process used to etch the lens is quite expensive, however, but the team is still researching ways to bring that cost down.

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