(under subclass 364) Subject matter including a doubly refractive or birefringent element, that is, an element having the property of dividing a ray of light into two polarized rays (known as the ordinary and extraordinary rays) the directions of polarization being at right angles to each other.
(1) Note. A birefringent material which has been treated with a dichroic dye to absorb the ordinary or extra-ordinary ray is no longer considered to be birefringent within the meaning of this definition. However, a birefringent element in the form, for example, of a Nicol prism where the unwanted ray is deflected would be classified here.
SEE OR SEARCH CLASS
359, Optics: Systems (Including Communication) and Elements, for polarization systems or elements having a birefringent element.
