Light refracting plates

Claim 1

A LUMINAIRE COMPRISING AN EXTENDED TUBULAR LAMP AND A SUBSTANTIALLY PLANAR REFRACTING PLATE, DISPOSED IN THE PATH OF DIRECT LIGHT FROM SAID LAMP, SAID PLATE HAVING ON THE LIGHT-INCIDENT SURFACE A PLURALITY OF PRISMS ARRANGED IN LATERALLY SPACED AND PARALLEL RELATIONSHIP, AND EXTENDING TRANSVERELY OF SAID LAMP AND TOWARD THE SAME FOR CONTROLLING THE DIVERGENCE OF LIGHT LONGITUDINALLY THEREOF, THE OUTER CONFIGURATION OF EACH OF SAID PRISMS IN TRANSVERSE CROSS-SECTION BEING QUADRILATERAL ABOVE A BASE PLANE THEREOF AND INCLUDING TWO OPPOSING SIDES CONVERGING UPWARDLY FROM THE BASE PLANE AND TERMINATING AT THE EDGES OF A TRUNCATED TOP, SAID OPPOSING SIDES BEING SYMMETRICALLY DISPOSED ON EITHER SIDE OF A PLANE EXTENDING PERPENDICULARLY TO THE BASE PLANE, SAID TRUNCATED TOP OF EACH OF SAID PRISMS INCLUDING A PAIR OF DOWNWARDLY CONVERGING TOP SURFACES EXTENDING IN CONVERGING PATHS FROM THE UPPER EDGES OF SAID OPPOSING SIDES, AND THE SLOPE ANGLE OF SAID OPPOSING SIDES MEASURED WITH RESPECT TO THE VERTICAL IS EQUAL TO THE SLOPE ANGLE OF SAID DOWNWARDLY CONVERGING TOP SURFACES MEASURED WITH RESPECT TO THE HORIZONTAL.