Ultra sensitive displacement detection of micromechanical structures

Recent advances in Micro-Electro-Mechanics have led to the development of many types of microsensors and microactuators. These devices have a typical range of motion from submicrometers to a few micrometers. Compared with macroscopic sensors and actuators, these micromachined devices are light weight, compact and can possess a higher frequency response. Until now, the most common method of visually observing the motion of these micromechanical devices have been using a Scanning Electron Microscope (SEM). There is an increasing need for a simple yet sensitive technique for detecting very fine motions of these devices. In this paper, we propose an optical detection scheme based on the Moire effect to achieve high resolution. Using a simple image processing technique, a resolution of 50 nm has been achieved.