Patent ID: 8346048

Claim:
An illumination device comprising: a light guide having a first end for receiving light and configured to support propagation of light along the length of the light guide; a turning microstructure disposed on a first side of the light guide configured to turn light incident on the first side and to direct the light out a second opposite side of the light guide, wherein the turning microstructure comprises a plurality of indentations; a cover physically coupled to the light guide and disposed over the turning microstructure; an interlayer between the cover and the light guide, wherein the interlayer physically couples the cover to the light guide, wherein the interlayer comprises a surface energy of less than about 25 dynes/cm; and a plurality of open regions between the interlayer and the plurality of indentations; wherein the light guide has a first index of refraction and the interlayer has a second index of refraction and the second index of refraction is lower than the first index of refraction.