Optical metrology for immersive display components and subsystems

Optical systems for immersive displays incorporate a range of optical components and assemblies that require precision non-contact metrology, including Fizeau interferometry of surface form, new techniques for aspheric microlenses, and interference microscopy for surface structure and texture analysis. Here we consider the problem of evaluating the parallelism and surface form deformation for stacked assemblies of multiple flat glass substrates. Similar structures are common for RGB planar waveguides with slanted sub-wavelength gratings acting as in- and out-couplers. In our experiments, we demonstrate the effectiveness of coherence scanning over a large aperture area using an 100-mm aperture white-light interferometer.