A Micromirror Module using a MEMS Digital-to-Analog Converter and its Application for White-Light Interferometry System
Date Issued
2010
Date
2010
Author(s)
Liao, Hsin-Hung
Abstract
In this work, we develop a microelectromechanical digital-to-analog converter mirror module (M-DACMM), and demonstrate its application for non-contact optical surface profiling systems. The proposed device generates nano-scale step motions that are proportional to input digital signals. The M-DACMM device, which consists of a large-area mirror, a digital-to-analog converter and 8 electrostatic parallel-plate actuators, can be monolithically fabricated by using a proposed micromachining process. Also, the process is suitable for releasing a large-area mirror (1mm in diameter) without the need of etching holes on the mirror surface. The transient responses of the mirror module are also measured and discussed. The switching time between two input binary states is less than 80 ms. The measured full-scale displacement is 1050 nm, and the motion step is 72 nm. The M-DACMM device has advantages of high position accuracy, high repeatability, and small size. Also, the device can be easily controlled by a simple actuation circuit. The M-DACMM is successfully installed on a white-light interferometry system as a reference mirror module. The surface-profiling results measured by the system are also presented.
Subjects
digital-to-analog converter
micromirror
MEMS, white-light interferometry
Type
thesis
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