Optimally Designed Electrostatic Microactuators for Hard Disk Drives

The rotary electrostatic microactuators integrating optimally curved electrodes are proposed to enhance the actuating force-generation capability. In most of conventional type of electrostatic microactiators using rotary mode, the electrodes have not been rigorously evaluated in terms of optimality for the shape and simply have been adopted in a straight shape. As a result, two neighboring electrodes should be spaced in the way of leading to larger clearance at the outer region from the center of rotation, hence the force generation capability is inherently limited. To overcome the limitation, the optimally curved electrode shape is introduced by tilting the electrodes in a continuous manner along with the radius. The simulation results show enhanced capability over the conventional shape for the current application to hard disk drive device. Microactuators were fabricated with the aspect ratio of 4:45 by using Inductively Coupled Plasma Reactive Ion etching. Experiments are carried out to measure the performance and the experimental results indicate the increased capability of the proposed type.