Finite Element Modeling of a High Speed Optical Depth Scanner

Abstract

A rotational high-speed depth scanner for an optical low-coherence reflectometer used for 3-D retina scanning has been developed and analyzed. A rotational speed of 427’000 rpm (in the range between the 4th and 5th critical speed) has been reached for the 5 × 5 × 2 mm3 BK7 glass cube, resulting in a record scan rate for this kind of instrument. This paper reports on our experimental results as well as the FE-modeling of the rotor and the internal-reflection glass cube under centrifugal stress, and on the interplay of mechanical deformation and optical performance. The scanner is mounted on air bearings and driven by an air turbine.