Surface deformation actuation structure

A surface deformation actuation structure, comprising:

• a deformable membrane that has a first surface and a second surface opposite said first surface;
• an array of actuators located facing the second surface, each actuator having an actuating surface, each actuator being arranged to actuate displacement of the actuating surface substantially perpendicularly to the second surface;
• and
• an array of actuating connections, each coupled to the actuating surface of a respective one of the actuators in the array and a respective point of the second surface substantially opposite the actuating surface, each actuating connection having anisotropic stiffness, substantially transmitting movement perpendicular to the second surface and leaving planar displacement and/or local rotation of the second surface substantially free, wherein the array of actuators comprises:
• a variably magnetizable base plate,
• an array of variably magnetizable islands on said base plate,
• actuator coils, each running around a respective one of the islands,
• a system of variably magnetizable walls on the base plate, the walls dividing a surface of the base plate into separate cells, each containing a respective one of the islands and coils, and
• a variably magnetizable resilient surface, with surface parts that each rest on at least one of the walls of respective cells, extend over a respective one of the islands and contain a respective one of the actuating surfaces.