US Patent 8198974 Flexible electrostatic actuator

An electrostatic actuator having a base including a first electrode and a flexible membrane including at least two material layers of different materials in contact with each other. At least one of the material layers includes a second electrode electrically isolated from the first electrode. The flexible membrane includes a fixed end connected to the base and a free end opposite the fixed end and spaced apart from the base. The second electrode has at least first and second portions separated by a third portion and in combination defining a first and second step provided in a vicinity of the fixed end.