Runway light with shallow optical system

Claim 1

A SHALLOW OPTICAL SYSTEM ADAPTED TO BE HORIZONTALLY MOUNTED, SAID OPTICAL SYSTEM COMPRISING: A REFRACTING LENS HAVING A FOCAL POINT LOCATED LATERALLY REARWARD OF AND SLIGHTLY BELOW SAID LENS; A LIGHT SOURCE POSITIONED PROXIMATE SAID FOCAL POINT FOR PROVIDING A DIVERGING LIGHT BEAM; A LIGHT ENTRANCE FACE REARWARDLY AND DOWNWARDLY DISPOSED AT THE REARWARD END OF SAID LENS AND DISPOSED TOWARD SAID LIGHT SOURCE, SAID ENTRANCE FACE HAVING SUBSTANTIALLY THE CONTOUR OF A PORTION OF A HYPERBOLOID OF REVOLUTION ABOUT AN AXIS WHICH CONTAINS SAID FOCAL POINT AND WHICH IS DISPLACED FROM THE HORIZONTAL, SAID AXIS OF REVOLUTION TILTED UPWARDS AND TOWARDS THE CENTER OF SAID LENS, SAID ENTRANCE FACE REFRACTING THE PORTION OF SAID DIVERGING LIGHT BEAM WHICH STRIKES THEREON INTO A SUBSTANTIALLY PARALLEL BEAM OF LIGHT WHICH IS SUBSTANTIALLY PARALLEL TO SAID AXIS OF REVOLUTION; AND A FLAT LIGHT EXIT FACE FORWARDLY AND UPWARDLY DISPOSED ON THE FORWARD END OF SAID LENS, SAID LIGHT EXIT FACE SLOPING UPWARDS AND TOWARDS THE CENTER OF SAID LENS, THE PERPENDICULAR TO THE PLANE OF SAID LIGHT EXIT FACE BEING ANGULARLY DISPLACED FURTHER FROM THE HORIZONTAL THAN SAID AXIS OF REVOLUTION, AND SAID EXIT FACE REFRACTING SAID PARALLEL BEAM INTO A HORIZONTAL LIGHT BEAM.