(under subclass 686) Subject matter wherein the plus and minus signs indicate convergent and divergent groups, respectively.
(1) Note. The arrangement along the optical axis of the lens is identified by the left most sign representing the group at the entrant face of the lens, i.e., the direction of light travelling through the lens is the same as the reading arrangement of the subclass title.
SEE OR SEARCH THIS CLASS, SUBCLASS:
775, for a +- -+ arrangement in general multiple component lens having four components.