Friday, February 10, 2006

Fluid lenses feel the pressure

Physicists have demonstrated a new type of tunable liquid lens whose focus can be changed simply by varying the pressure on it. The lens is formed from the curved interface between a liquid and air at the exit of a small aperture. Such lenses do not require any mechanical parts, are much smaller than traditional lenses and can be focused with high precision. They could be used in web cams, mobile phone cameras and portable medical devices.

The new lens has been designed by Saman Dharmatilleke and colleagues at the Institute of Materials Research and Engineering (IMRE) in Singapore. It was made by housing a tiny drop of water -- or any other liquid with a high surface tension -- in the small aperture of a well. Applying pressure to the drop via an actuator changes the radius of curvature -- and hence the focal length -- of the drop. The focal length can therefore be tuned simply by varying the amount of pressure applied. The lenses can be made either from a liquid-air or a liquid-liquid interface.


No comments: