SURFACE-CURVED OPTICAL ELEMENT ADAPTED FOR EMERGENCE AND INCIDENCE OF PARALLEL LIGHT RAYS

摘要

The invention relates to an optical element being conveniently useful, for example as an external cover of transmitter and/or receiver for optical communication and more particularly to a surface-curved optical element comprising a transparent body of a refractive index n having a pair of boundary surfaces defined in their crosssection by the corresponding pair of ellipsoidal curves of an eccentricity l/n. The boundary surfaces of this surfacecurved optical element are configured so that they should have their focal points aligned with one another on a straight line and their focal points which are remote from vertices of the respective ellipsoidal surfaces corresponding to the apsides of the respective ellipsoidal curves should be coincident with each other, whereby parallel light rays entering the surface-curved optical element should emerge from this in the form of the parallel light rays without any disturbance.