Double refraction measurement method - uses electromagnetic wave spectrum in ultra-violet, visible and infra-red ranges

摘要

By this method, and using polarisation optical systems the double refraction in optically active materials can be quickly determined, thus obtaining a test quantity by which the anisotropy produced in the finished transparent or translucent object by the manufacturing processes, and thus the object quality can be judged. An analysis of the transmission or absorption spectrum is used for determination of the propagation difference of the perpendicular to each other light wave component of a linearly polarised input light wave, produced by the existing anisotropy; the test result is used as output signal for control of a manufacturing process, e.g. of a plastic foil, or for continuous or quasi-continuous quality control by computer.