Electrostatically driven micro elastic joints

An electrostatic actuator which can be applied to the joints of movable parts in a micro system was developed. An elastic plate (length: 105-520 μm width: 13 μm, thickness: 0.5-1.3 μm) is bent by electrostatic force when a voltage of 40-100 V is applied The required voltage depends mainly on the initial curvature of the elastic plate. This curvature can be controlled by changing the thickness ratio of the Al and Ni layers, which are sandwiched together to comprise the elastic plate. It was found that the radius of curvature is mainly proportional to the thickness ratio (Ni thickness/Al thickness) in the range of 0.1 to 0.4, and that the gradient of its proportion is larger when the Al film is thicker. Control of the elastic film curvature also enables the fabrication of three dimensional mechanisms without handling or assembly