OPTICAL INTEGRATOR AND ILLUMINATION DEVICE USING THE SAME

An illumination device is providing a flat top rectangular illumination beam exhibiting a substantially uniform transversal intensity distribution and a specified numerical aperture. A collimated or diverging light beam having a possibly non-uniform transversal intensity distribution is transformed into a rectangular, substantially uniform flat top light beam by homogenizing the light beam with an optical integrator comprising a pair of mutually orthogonal planar light guides and relay optic system that focuses the illumination beam outgoing form the first planar light guide onto a front face of the second planar light guide and images an exit face of the first planar light guide onto a plane of an exit face of the second planar light guide. Said flat top rectangular light pattern at the exit facet of the second planar light guide is relayed onto an illumination target.