(under subclass 33) Subject matter wherein the test apparatus utilized in examining articles or materials includes a detector which is naturally birefringent or forced by stress to be birefringent, and means to attach the detector to the articles or materials so that the strain placed on the articles or materials is imparted to the detector so that the modification of the light associated with the detector is indicative of the strain in the stressed article or material.
SEE OR SEARCH THIS CLASS, SUBCLASS:
51, where infrared and ultraviolet light is involved in the test.
364, for polarized light examination apparatus which produces interference patterns created by the interaction of beams of polarized light.
SEE OR SEARCH CLASS
359, Optics: Systems (Including Communication) and Elements,
483+, for polarizing structure generally. See also (1) Note of subclass 33.
