We have demonstrated using a commercial white light interferometric microscope, a Wyko NT-2000 surface profiler, to visualise the dynamic motion of a micromachined device. This involves the relatively simple modification of replacing the standard halogen bulb with an LED source to operate stroboscopically, synchronised to the drive signal of the micromachined device.
Schematic of experimental setup.
The results shown here are all for a sinusoidal excitation. The devices move at twice the excitation frequency as the electrostatic driving force depends only on the magnitude of the signal.
Example images for 1KHz excitation at 0, 0.2 and 0.3ms after zero crossing of drive signal.