Front light module

Abstract

A front light module includes a light guide plate having opposite ends and a front surface and an opposite back surface connected to each other by the ends. The front surface forms sets of raised ridges, each raised ridge having opposite inclined faces. The front surface also forms a recessed trough between adjacent sets of ridges. Each trough has opposite inclined faces. A light source is mounted to each end of the light guide plate for projecting a light into the light guide plate. A reflector is arranged adjacent to and spaced from the back surface of the light guide plate for accommodating a display board between the reflector and the light guide plate. The light from the light source is incident onto the inclined faces of the troughs and reflected thereby toward the reflector. The troughs have different depths whereby the inclined faces thereof are of different surface areas for reflecting different amount of light in order to provide a uniform brightness over the whole module. The light is then reflected by the reflector toward the front surface where the light is refracted by the inclined faces of the ridges to increase the viewing angle of the light guide plate. The ridges may have a triangular cross section or alternatively, the ridges have a trapezoidal cross section having a top face forming ribs. The troughs may have a trapezoidal cross section having a flat bottom face that allows for adjustment of distance between adjacent ridge sets.