| 摘要 |
A light extraction overlay for extracting light from a desired location on a light guide includes a substantially optically transparent substrate which has a base surface and a structured surface opposite the base surface. The structured surface includes optical elements which have optically smooth surfaces disposed at an angle relative to the base surface. Preferably, the optical elements are coated with a specularly reflective material. The optical elements may be separated by substantially planar portions of the structured surface. In use, the base surface is optically coupled with a portion of a surface of a light guide such that light may be transmitted from the optical fiber into the substrate. Light rays which strike a planar portion of the structured surface are reflected back into the fiber at an angle which is greater than the critical angle necessary for continued propagation in the light guide and, accordingly, continue to propagate along the optical fiber. Light rays which strike an optical element are reflected into the fiber at an angle less than the critical angle angle necessary for continued propagation in the light guide and, accordingly, are transmitted from the surface of the light guide. |
