ASTIGMATIC OPTICAL ELEMENT, ITS MANUFACTURING PROCESS, ILLUMINATING APPARATUS INCLUDING THE SAME AND ARTICLES TREATED BY THE SAME

摘要

An optical element, by example a mirror, has an optically polished surface wnich is far from a plane or spherical surface. According to the invention, a flat member 22 is machined along a second face so that thickness of flat member varies. First face is then optically polished when it is plane. Flat member 22 is then distorted so that polished surface takes a neither plane nor revolution shape, Such mirrors are used for distributing laser beam energy along lines or over extended areas with constant energy density.