| abstract |
A focussing system including an optical element (14, Fig 7 ) which comprises at least one cell (14) having two deformable dielectric layers (4, 5, Fig 1 ) which meet at an interface, at least one of which (5) is a relief forming gel, a first electrode (6) on one side of the layers and a signal electrode (3) on the other side of the layers, the electrodes being provided on dielectric substrates. Means (18) supplies voltage pulses which are applied to the signal electrode in accordance with desired signals. The interface between the deformable layers is curved and at least one of the substrates is transparent and is also curved, so that the optical element (14) focuses light. |