The present invention relates to an illumination system for use in a stereolithography apparatus. The illumination system includes a plurality of light-emitting diodes (LEDs), each LED having at least a first light-emitting surface and a second surface, at least one of the first and the second surface being substantially flat. The illumination further includes a plurality of electrical pathways, selectively connected to the respective LEDs, such that each LED can be individually controlled and a leveling surface. The leveling surface is substantially flat and in leveling contact with the at least one substantially flat surface of each LED, such that a two-dimensional array of LEDs extends in a plane parallel to the leveling surface.