Patent ID: 7480101

Claim:
An optical layer comprising a light output side and a light input side having a light input side plane, the optical layer comprising: a plurality of three-dimensional light collimating elements, wherein each light collimating element comprises: a light input end having a predetermined input aperture; a light output end; and, a polygonal horizontal plane cross-section; wherein each light collimating element is tapered to comprise at least one linear section and at least one curved section in a vertical plane cross-section of the light collimating element that is an approximation of a compound parabolic concentrator, wherein the curved section is defined by an arc of a circle, and a slope of the curved section matches a slope of the at least one linear section at an intersection point of the at least one curved section and the at least one linear section, such that uncollimated light entering the predetermined input aperture from multiple angles emerges from the light output end as a substantially collimated uniform sheet of light; and a reflective surface, wherein the reflective surface is on the light input side plane of the optical layer, and is adjacent to the predetermined input aperture of the light input end of each light collimating element, and provides recycling of light for input to the optical layer when the reflective surface of the optical layer faces and is opposite a reflective surface of a light source.