Patent ID: 7690814

Claim:
A luminaire comprising: (a) a light source whose light output is constrained within a first predefined glare-restricted angular extent about an axis; and (b) a transparent optical diffuser spaced at a distance from said light source and having a planar first surface facing said light source and an opposing second surface including a plurality of light altering tracks comprising an alternating series of planar sloped surfaces and cylindrical lens elements, each of the cylindrical lens elements being between and adjacent to two of the planar sloped surfaces, a size of the planar sloped surfaces increasing with distance from a centerline of said diffuser, and a thickness of said diffuser at each of the light altering tracks being substantially uniform, (i) wherein each light altering track receives a limited first solid-angle of said light by virtue of its distance from the light source, and (ii) wherein each light altering track distributes its received light over a larger second solid angle within a second predefined glare-restricted angular extent, the second predefined glare-restricted angular extent being smaller than the first predefined glare-restricted angular extent.