Patent ID: 8251527
Filing Date: 2012-08-28
Classification: G02B

Abstract:
1. A light duct bend, comprising: a light duct having an inner sidewall, an outer sidewall, a top, and a bottom, forming an interior cavity having specular reflective surfaces; an input region in the light duct, having a first light propagation direction; an output region in the light duct, having a second light propagation direction forming a bend angle θ with the first light propagation direction; a transition region connecting the input region to the output region, wherein the inner sidewall follows an inner radius, and the outer sidewall follows an outer radius; a plurality of vanes separating the transition region into channels, each of the plurality of vanes following an associated vane radius between the inner radius and the outer radius, wherein a major portion of a partially collimated input light beam having a divergence angle that enters the input region, exits the light duct from the output region within the divergence angle, wherein the divergence angle is less than about 30 degrees.