Runway lighting unit

Claim 1

IN AN OPTICAL SYSTEM, THE COMBINATION COMPRISING: (A) A SHALLOW HOUSING ADAPTED TO BE MOUNTED GENERALLY HORIZONTALLY AND HAVING A SHALLOW GENERALLY RADIALLY DISPOSED TROUGH IN THE TOP SURFACE THEREOF, SAID HOUSING PROVIDED WITH AN ELONGATED OPENING TRAVERSING THE INNER END OF SAID TROUGH; (B) ELONGATED LIGHT-REFRACTING MEANS LOCATED IN THE ELONGATED OPENING PROVIDED IN SAID HOUSING, SAID LIGHT-REFRACTING MEANS HAVING A SUBSTANTIALLY FLAT EXTERIOR SURFACE WHICH SLANTS UPWARDLY AND AWAY FROM SAID TROUGH, AND SAID LIGHT-REFRACTING MEANS HAVING AN INTERIOR SURFACE WHICH IS DISPOSED NEARER TO THE VERTICAL THAN THE SLANTING EXTERIOR SURFACE OF SAID LIGHT-REFRACTING MEANS TO CAUSE LIGHT STRIKING SUCH INTERIOR SURFACE AND TRAVERSING SAID LIGHT-REFRACTING MEANS TO BE REFRACTED DOWNWARDLY UPON EXIT FROM THE EXTERIOR SURFACE THEREOF; (C) ELONGATED REFLECTOR MEANS SUPPOTED WITHIN SAID HOUSING AND SPACED A SUBSTANTIAL DISTANCE LATERALLY FROM AND ALSO LOWER THAN SAID LIGHT-REFRACTING MEANS ON THE OPPOSITE SIDE THEREOF FROM SAID TROUGH AND FACING THE INTERIOR SURFACE OF SAID LIGHT-REFRACTING MEANS, SAID ELONGATED REFLECTOR MEANS HAVING A PREDETERMINED CONFIGURATION WITH DEFINES A FOCAL POINT POSITIONED INTERMEDIATE SAID LIGHT-REFRACTING MEANS AND THE BODY OF SAID REFLECTOR MEANS, WITH LIGHT GENERATED PROXIMATE THE FOCAL POINT OF SAID REFLECTOR MEANS AND EMANATED TOWARD SAID REFLECTOR MEANS BEING REFLECTED THEREBY SUBSTANTIALLY UNIFORMLY ONTO THE INTERIOR SURFACE OF SAID LIGNT-REFRACTING MEANS; AND (D) LAMPHOLDER MEANS AFFIXED WITHIN SAID HOUSING AND ADAPTED TO SUPPORT LIGHT SOURCE PROXIMATE THE FOCAL POINT OF SAID REFLECTOR MEANS; WHEREBY LIGHT GENERATED PROXIMATE THE FOCAL POINT OF SAID REFLECTOR MEANS IS REFLECTED THEREBY SUBSTANTIALLY UNIFORMLY ONTO THE INTERIOR SURFACE OF SAID LIGHT-REFRACTING MEANS AND IN TURN IS REFRACTED DOWNWARDLY BY SAID LIGHT-REFRACTING MEANS AS A BEAM WHICH IS GENERALLY HORIZONTAL AND PASSES THROUGH THE TROUGH PROVIDED IN SAID HOUSING.