ILLUMINATION SYSTEM WITH REDUCED ENERGY LOADING

PROBLEM TO BE SOLVED: To provide an illumination system in which the energy load on an objective is reduced in the interior of the objective. SOLUTION: The illumination system (1) contains a rod type integrator (3) and a succeeding objective lens (11). The rod type integrator (3) is provided with an entry surface (5), an exit surface (7) and a reflecting side surface (9). The objective (11) is provided with a lens-free interspace (17) at least 30 mm thick (dLF) in the axial direction. The level is present in the interior of this interspace. The level is optically conjugated with the level of the entry surface (5). All beams (21) which are emitted from the central field (19) in the interior of the entry surface (5) of the rod type integrator (3) and not reflected on the side surface (9) has lower heights with respect to the optical axis(OA) than that of a beams (23) which are emitted from the same central field (19) in the lens-free interspace (17) and reflected from the side surface (9).