Optimally designed electrostatic microactuator for hard disk drives

The rotary electrostatic microactuators integrating optimally curved electronics are proposed to enhance the actuating force-generation capability. In most of the conventional type of electrostatic microactuators using rotary mode, the electrodes have not been rigorously evaluated in terms of optimality for the shape, but have simply been adopted in a straight shape. As a result, two neighboring electrodes should be spaced leading to a larger clearance at the outer region from the center of the rotation, hence the force generation capability is inherently limited. To overcome this limitation, the optimally curved electrode shape is introduced by tilting the electrodes in a continuous manner along with the radius. The simulation results show an enhanced capability over the conventional shape for the current application to a hard disk drive. Microactuators were fabricated with the aspect ratio of 4:45 by using the inductively coupled plasma reactive ion etching. Experiments results obtained indicate the increased capability of the proposed type.