Rapid detecting z-position of moving objects in microchannel utilizing a novel chromatic aberration effect under a dark-field illumination scheme

Detecting the z-position of moving particles in an embedded microchannel is important but challenging in MEMS fields, hence this research describes a novel technique for detecting the z-position of moving objects utilizing chromatic aberration. With this simple and novel approach, the depth of moving object can be measured without delicate optical system. Results show that the developed system gives a large detection range of 30 μm with a high linearity. The resolution for this depth detection is estimated to be 0.136 μm. The developed depth detection scheme provides a simple but high performance way to dynamically identify the z-position of micro moving parts in MEMS application.