BEAM TRANSDUCER ELEMENT, ILLUMINATION OPTICAL SYSTEM USING THE BEAM TRANSDUCER ELEMENT, ALIGNER, LASER PROCESSING MACHINE AND PROJECTION DEVICE

摘要

PROBLEM TO BE SOLVED: To transduce a beam with intensity distribution of Gaussian distribution into a uniform and parallel beam by using a hologram element and not using a lens with a special shape of a cross section. SOLUTION: A beam transducer element 1 consists of a first hologram element 2 and a second hologram element 3 placed in parallel with each other. The first hologram element 2 is provided with a function of a concave lens and its focal length gets shorter being the nearer its center and the second hologram element 3 is provided with a function of a convex lens and its focal length gets shorter being the nearer its center. A light ray with significant intensity in the vicinity of a central part of a laser beam 4 is widely diverged by the first hologram element 2 and an angle of divergence caused by the first hologram element 2 gets smaller being the nearer its peripheral part. These light rays become a beam 5 with uniform intensity distribution with the second hologram element 3.