LCD display with brightness enhancement film illuminated from the front

摘要

A line light source comprising a point line source, e.g., a light emitting diode (LED), and a light pipe having a rectangular, e.g., square, cross-section. Light rays from the point light source enter one end of the light pipe and travel along the length of the pipe. The light rays are reflected off notches or step-facets on one of the four sides of the light pipe. The light rays then pass across the light pipe and exit from the side of the light pipe opposite the notched/faceted side. The square cross-section of the light pipe of the present invention preserves the modes emitted from the point light source, i.e., the cone of emission from the light pipe is about the same as that from the light source. The light source converts a point light source to a line light source which emits light rays at a relatively uniform intensity along the length of the light pipe.