This 100X Nomarski photo of microelectromechanical (MEMS)
clamped-clamped beams shows that the 800um and 1mm long
are buckled because of excessive compressive stress.
These beams are fabricated using polysilicon micromachining.
The airgap separating the capacitive electrodes formed
by the beams and the substrate narrows with applied voltage,
allowing the beam to deform and pull-in (contact). With
oscillating voltages, the beams can mechanically resonate
at several 10's of kilohertz and higher.
This 150X interferometric black and white image of an
unactuated octagonal mirror shows spherical curvature.
The AVI animation linked to the photo (Real
Audio Player needed, 776k,avi) is a sequence of static images
0 to 100 volts in 5 volt increments. Note: Between a
full-phase of intensity variations, each fringe
measures a surface height difference of 225nm.
The multiple fringes can be deconvolved to give a
precise and continuous elevation plot of the mirror
surface. By using IDEA an FFT-based deconvolver, the
interferometric data produces the following contour plot
This associated animation (1.8M,mpeg)
shows the dual-axis gimbal action of the
micromirror based on 3D FEM results from (CoventorWare).