ILLUMINATING OPTICAL SYSTEM AND OPTICAL DEVICE USING THE SAME SYSTEM, AND MANUFACTURE OF DEVICE USING THE SAME OPTICAL DEVICE

摘要

PURPOSE:To provide an illuminating optical system whose energy loss is small. CONSTITUTION:The system and device are provided with a prism unit 2 splitting a radial beam to plural illuminating beams, a cylindrical lens 4 bringing the respective plural illuminating beams into focus in terms of a splitting direction by means of the prism unit 2, and a convex lens 5 bringing the respective plural illuminating beams from the lens 4 into focus on a mask 6 in a direction orthogonally crossing with the splitting direction by means of the prism unit 2 and bringing it out of focus in the splitting direction. The respective plural illuminating beams are superposed on the mask 6 to form a linear illumination area.