Through-the-glass spectroscopic ellipsometry for simultaneous mapping of coating properties and stress in the glass

Through-the-glass mapping spectroscopic ellipsometry has been developed for simultaneous determination of the thicknesses and optical properties of thin films coated on glass as well as the optical anisotropy of the glass. The former has been correlated with solar cell performance, and the latter has been used to estimate the stress in the glass. The optical anisotropy has been observed to vary monotonically with externally applied stress over a wide range from zero to the upper limit that the glass can withstand. With this methodology, the stress distribution in full-size panels can be tracked through manufacturing steps and in the field.