Patent ID: 6974235

Claim:
In a luminaire for illumination of surfaces within an area within which the luminaire is disposed and having a light-transmissive member for controlling the direction of at least a portion of light emanating from the luminaire, the light-transmissive member having a wall and a multiplicity of prisms formed thereon, at least certain of the prisms being respectively adjacent and forming junctures between adjacent prisms, each prism having an apex defined by the intersection of elongate surfaces defining exteriorly oriented faces of each said prism, a light source disposed in opposed relation to said wall, the improvement comprising at least a portion of at least one face of at least certain of said prisms being non-linear in section, the non-linear portion of the at least one face of the prism being located in proximity to the valley between the prism and an adjacent prism, the non-linear portion of the face being a circular arc, apices of at least adjacent prisms being substantially disposed in alignment along an imaginary curve incongruent with an imaginary circular arc having a radius equal to the distance between a center of the light source and any one of the apices.