Construction of a time-domain full-field OCT for non-contact volumetric layer thickness measurement

Abstract

In this paper the design of a Time-Domain Full-Field OCT (TD-FF-OCT) setup for non-contact volumetric layer thickness measurement is presented and quantified in terms of achievable accuracy and performance. The capabilities of the instrument regarding its measuring accuracy are verified using foil thickness standards of different strength. Afterwards, a technical application of measuring a thin and rough varnish coated PET foil (foil thickness t f oil ≈ 150 µm, rough varnish layer thickness t varnish ≈ 10 µm) is carried out. Since the device is designed to conduct areal measurements, the thickness can be accurately determined over several measurement points. The results are compared with results achieved by applying an alternative but destructive and more time-consuming measuring method (evaluation of microscopic images of respective foil slices produced by using a microtome). Finally, the achievements are summarized and identified optimization potential is highlighted.