Asymmetrical light intensity distribution from luminaire

Abstract

In one embodiment, an overhead street light (a luminaire) is formed that has an asymmetric light intensity distribution, where the peak intensity is greatest along the direction of the street, lower directly across the street, and much lower on the house side of the street. Around the edge of a circular transparent light guide are white light LEDs that inject light into the light guide. To help control the asymmetry of the light intensity distribution, sawtooth-shaped grooves are formed in the light guide surface opposite to the light-emission surface and parallel to the street. Gaussian diffusers are used to partially diffuse the light. By proper selection of the grooves, the Gaussian diffuser, and the relative amounts of light emitted by LED segments around the light guide, the desired asymmetrical light intensity distribution is achieved while a direct view of the light exit surface appears as a uniform light.