Optimal filling of a polygon facet by beam reprofiling

摘要

A raster scanner system is disclosed which utilizes a pair of binary diffraction optic lenses to correct non-uniformity of the flux of a light beam received by a facet of a rotating polygon. Since the facet is rotating and the direction of the light is constant, the amount of the light (flux) which the facet receives in each position from the start of scan to the end of scan and in any position therebetween is different. Also, the light beam striking the rotating facet has a Gaussian distribution which is a contributor to the non-uniformity of the flux over one scan line. The binary diffraction optic lenses of this invention reprofiles the Gaussian distribution into a profile in which the intensity of the light beam gradually increases as the facet rotates to provide a uniform flux for the entire scan line.