Panoramic optical system having an annular afocal lens system

Claim 1

A PANORAMIC OPTICAL OBJECTIVE COMPRISING AN ANNULAR AFOCAL LENS SYSTEM, AN AXIALLY SYMMETRICAL REFLECTING ELEMENT ALIGNED WITH SAID LENS SYSTEM AND HAVING AT LEAST ONE SUBSTANTIALLY CONICAL REFLECTING SURFACE SO INCLINED WITH REFERENCE TO THE AXIS OF SAID ELEMENT AS TO REFLECT IN A GENERALLY AXIAL DIRECTION ALL INCIDENT RAYS ARRIVING FROM SAID ANNULAR LENS SYSTEM, AND A LENS MEMBER FOR FOCUSING RAYS REFLECTED FROM SAID SURFACE ONTO AN IMAGE PLANE, SAID ANNULAR LENS SYSTEM INCLUDING AT LEAST ONE ANNULAR COMPONENT OF NEGATIVE REFRACTIVITY IN ALL PLANES CONTAINING SAID AXIS AND BOUNDED BY TWO AIR SPACES AND SPACEDLY SURROUNDING SAID ELEMENT, AND A FURTHER ANNULAR COMPONENT OF POSITIVE REFRACTIVITY BETWEEN SAID ANNULAR COMPONENT OF NEGATIVE REFRACTIVITY AND SAID ELEMENT, SAID COMPONENTS FORMING AN AFOCAL SYSTEM.