Design of a precise X-Y-Theta nanopositioning optical sensor

Abstract

A position measurement system was designed to estimate the absolute and relative position of an x-y-[theta] nanopositioning stage for use in the metrology of microfluidic devices during and after manufacturing. The position sensing system consists of a visible-light high-speed area camera, a target pattern, and image processing software. The target pattern consists of a square grid with unique binary codes in each square that identify the square's global position in the grid. In macroscopic-scale testing of the position sensing system, the angular orientation of the target pattern was successfully measured with less than one degree uncertainty. However this uncertainty is several orders of magnitude larger than the target precision of the sensor, and it is still unclear whether sufficient precision is attainable with this system and software. This thesis also describes a previous attempt to perform this metrology using consumer-grade contact image sensor scanners, other elements of the current metrology system design, and the non-orthogonal viewing angle concept, which is the fundamental underpinning of the microfluidic metrology system as a whole.