STEMMER IMAGING to sell tunable polymer lenses for machine vision

Tunable focus is achieved by changing the shape of these flexible lenses which feature a container filled with an optical liquid and sealed with a thin, elastic polymer membrane. A circular ring pushes onto the centre of the membrane and the shape of the lens, and hence its focus, can be changed by moving the ring or exerting a pressure on the outer part of the membrane or by pumping liquid into or out of the container. A change in lens radius of several microns can have the same optical effect as moving the entire lens several centimetres. 

The liquid lenses do not replace conventional optics in a machine vision system. However, when being used with the appropriate optics they allow a much faster change of the focus than traditional solid glass or plastic-based optics which need to be moved backwards and forwards to focus or zoom. This means users benefit from smaller, cheaper and faster optical systems. 

Mark Williamson, Director – Corporate Market Development at STEMMER IMAGING said: “This is a very interesting technology which has many potential applications for machine vision. They are particular useful where objects of different height need to be measured, since the use of tunable lenses removes the need for mechanical actuators. This reduces both complexity in the set-up and the amount of space needed for the optics. In addition, lens response times of the order of just milliseconds can accommodate high throughput inspections.”