(under subclass 642) Subject matter wherein the lens has or produces unequal magnifications in two planes that are at an angle (usually perpendicular) to each other.
(1) Note. These lenses employ at least one element or component having one or more cylindrical surfaces thereupon to produce the unequal magnifications of the lens.
SEE OR SEARCH THIS CLASS, SUBCLASS:
710, for lenses having elements or components with one or more cylindrical surfaces thereon.
