Patent ID: 8480276

Claim:
An elongated lighting system, comprising: a) an elongated light pipe having first and second ends; b) at least one light source for supplying light to the light pipe via said first and second ends; c) first and second light couplers interposed between the at least one light source and said first and second ends, respectively; wherein the first and second couplers each have a profile from an inlet end to an outlet end for conditioning the angular distribution of light from an associated light source so that at least 70 percent of the light provided to the light pipe totally internally reflects within the light pipe; d) the light pipe having an indentation formed transverse to a central path of light propagation through the light pipe and having two spaced ends along the central path of light propagation; the primary means for extracting light from a side of the light pipe, along the central path of light propagation between said first end and the indentation, is a light-extraction means on the light pipe situated between said first end and the indentation; a plane, orthogonal to said central path of light propagation through the light pipe, existing in the light pipe at an end of the indentation that is closest to said first end; e) the indentation having a depth and having surfaces oriented with respect to the light pipe so as— i. to redirect at least 25 percent of the light from the first light source that reaches the indentation after passing once through said plane, back through the plane and towards said first end; and ii. to sufficiently increase the average angular distribution of light reflected from the indentation and passing back through the plane as would cause at least 50 percent more total internal reflections of the foregoing light within the light pipe in the absence of said light-extraction means compared to the earlier passage of the light from the first light source through said plane.