A flexible light guide film having a light-adjusting structure in the form of a lenticular-like microstructure on the bottom side of the light guide film. The light guide film has a substrate layer supporting a layer light-adjusting structure, which is in the form of an array of longitudinal lenticular lenses laterally arranged in parallel. A prismatic-like microstructure may be provided on the top light emitting side of the light guide film. The light guide film is fabricated by a process involving coating/embossing of a roll of sheet material, in a roll-to-roll continuous process. Advantages includes significantly reducing the thickness of the light guide film, and the roll-to-roll fabrication process provides for more precise replication of the microstructures on the master mold or drum onto the surface of the light guide film, which in turn reduces the failure rate and manufacturing cost.