An optic film has a surface on which a plurality of rib-like micro light guides is formed. Each light guide includes a plurality of ridges, which are of different height and shows variation of height. Either a high ridge or a low ridge of the light guide is made a continuous left-and-right wavy configuration and/or a continuous up-and-down height-variation configuration. Thus, light transmitting through the optic film and converged by the light guides leaves the optic film in a form that is not very regular so as to facilitate subsequent use of the light in for example a liquid crystal display panel.