US 7,455,422 B2
Light fixture and lens assembly for same
Carl T. Gould, Boulder, Colo. (US); John T. Mayfield, III, Loganville, Ga. (US); Gary D. Trott, Eatonton, Ga. (US); and Christopher L. Sharp, Conyers, Ga. (US)
Assigned to ABL IP Holding LLC, Conyers, Ga. (US)
Filed on Aug. 27, 2007, as Appl. No. 11/845,640.
Application 11/845640 is a division of application No. 10/970625, filed on Oct. 21, 2004, granted, now 7,261,435, filed on Aug. 28, 2007.
Claims priority of provisional application 60/580996, filed on Jun. 18, 2004.
Prior Publication US 2007/0291481 A1, Dec. 20, 2007
This patent is subject to a terminal disclaimer.
Int. Cl. F21S 4/00 (2006.01)
U.S. Cl. 362—223  [362/337; 362/339] 74 Claims
OG exemplary drawing
 
1. A lens assembly for directing light emitted from a light source toward an area to be illuminated, the light source being elongated along a light source longitudinal axis, the lens assembly comprising:
an elongate lens extending along a lens longitudinal axis parallel to said light source longitudinal axis and having a central lens portion curved in a plane transverse to the lens longitudinal axis that defines a prismatic face that is oriented toward and spaced from said light source and an opposed, substantially smooth, exterior surface; and
a means for generating a plurality of spaced elongate stripes of reduced brightness to control high angle glare in the longitudinal direction optically, comprising a plurality of adjoining elongate prismatic elements formed on the prismatic face of the central lens portion that extend parallel to said lens longitudinal axis, wherein each prismatic element has a curved surface facing said light source, wherein at least a section of the plurality of elongate prismatic elements, in a plane transverse to the lens longitudinal axis, has a shape of a continuous wave, wherein each pair of adjoining elongate prismatic elements form a common elongate cusp edge, wherein each elongate prismatic element of the plurality of adjoining elongate prismatic elements is configured such that a reverse ray impacting the elongate prismatic element proximate the common cusp edge at an angle of incidence ω of at least about 40° will undergo total internal reflection and be reflected back into the area to be illuminated to form a stripe of reduced brightness on the exterior surface of the lens, and wherein each stripe of reduced brightness extends substantially parallel to the lens longitudinal axis.