Light emitting diodes are arranged in a matrix under an incident surface of a light guide panel. The incident surface includes a plurality of incident blocks arranged with each incident block respectively positioned beside a corresponding LED. Each incident block includes a plurality of surfaces having different normal vectors or curvature radiuses for scattering light emitted from the corresponding LED. A reflection film may be used to reflect light generated from the plurality of LEDs and a diffuser sheet may be positioned at one side of a light-exit surface of the light guide panel.