Patent ID: 7184615

Claim:
An optical device comprising at least a substantially planar waveguiding substrate for guiding a light wave within the substrate in a direction of a substrate plane based substantially on total internal reflections, a preformed, diffractive grating structure carried by the waveguiding substrate and arranged to couple energy of the light wave between the substrate and surroundings thereof, wherein said preformed, diffractive grating structure is a preformed surface relief arranged on an electrically deformable dielectric and viscoelastic layer, and that the device further comprises at least a first substantially transparent_electrode structure arranged between the waveguiding substrate and the viscoelastic layer, a second substantially transparent electrode structure arranged opposite to the viscoelastic layer leaving a dielectric gap towards a free surface of the viscoelastic layer having a surface relief, and control module, for applying a control voltage between the first and second electrode structures to generate an electric field passing through an interface between the viscoelastic layer and the dielectric gap in order to electrically deform the surface relief of the viscoelastic layer.