Automatic stress double refraction measurement in transparent bodies involves illuminating, converting to linear polarization, measuring light intensities with increasing analyzer angle from null, storing angle for first minimum intensity

摘要

A surface of the transparent body (5) is illuminated with linearly polarized light (L1), and the light emanating from the surface, possibly elliptically polarized, is converted into linearly polarized light (L2). An image of the surface is formed with an interposed analyzer (7) rotatable about an z-axis onto a surface detector (10) in the beam path that is fixed with respect to an x-y plane. Light intensities are measured with each of a number of detection elements starting from a null position with increasing rotation angles of the analyzer, and the rotation angle at which the first minimum intensity is reached is stored. An independent claim is also included for a device for automatic measurement of stress double refraction in transparent bodies.