US Patent 7524091 Led bulb refractive relector

A light guide may be made from a plurality of substantially planar, light transmissive arms paralleling and radiating from a common axis. The planar arms in combination define a common cavity extending along the axis sufficiently large to envelope a light source. At least one arm has an input window facing the common cavity, a reflective wall aligned with respect to the common cavity and an input window. Light received from the direction of the common cavity through the input window is generally reflected in an axial direction. The light guide has an output window extending from an intersection point with the reflective wall towards the axis. The plurality of arms is preferably supported on a base.