Light-collimating film

A light-collimating film includes a transparent substrate, multiple reflective elements, and multiple micro structures. The transparent substrate has a light incident surface and a light-emitting surface opposite the light incident surface. The reflective elements are formed on the light incident surface, wherein each two adjacent reflective elements define a longitudinal aperture. The micro structures are arranged on the light-emitting surface in a direction parallel to longitudinal axes of the longitudinal apertures and overlap the longitudinal apertures to form multiple rows of micro structures. The micro structures include a first side portion to deflect a first light beam incident thereon toward a first virtual central plane of the micro structure which equally divides the micro structure, and a second side portion to deflect a second light beam incident thereon toward a second virtual central plane of the micro structure which is substantially perpendicular to the longitudinal axis of the longitudinal aperture.