Patent ID: 8896003

Claim:
A separate optical device comprising: an entrance surface to receive light from a light source; an exit interface parallel to the entrance surface, the exit interface having a rectangular shape; and a set of shaped sidewalls, wherein each sidewall has a plurality of sections each section of a sidewall defined by a different contoured surface such that each sidewall comprises a superposition of multiple contoured surfaces, each section adapted to reflect light with a direct transmission path from the entrance surface to that section such that light is reflected through total internal reflection to the exit interface to be incident on the exit interface at less than or equal to a critical angle at the exit interface, and wherein an area of the exit interface, a distance between the entrance surface and exit interface, and sidewall shapes are selected so that the separate optical device is configured to emit at least 65% of light entering the separate optical device through the entrance surface from the exit interface in a selected half angle, wherein the selected half angle is a half angle from 20 to 60 degrees.