Abstract

A scan lens for a laser printer system consists of an F-θ lens and a scanning element, typically a polygon mirror. Due to mechanical wobble and facet-to-facet misalignment, a polygon mirror tends to steer the focused beam out of the intended scan line and therefore requires some form of optical compensation. The most common method¹ makes use of anamorphic optical elements. Traditionally, lenses based on this approach contain either a toroidal surface or a reflective cylindrical field lens, both of which are relatively expensive. It is possible to use a diffractive surface to replace the need for either of these surface types. Non-toroidal hybrid scan lenses have been discussed previously²,³. These designs were limited to rotationally-symmetric geometries and therefore could not be used with polygon mirrors. This paper discusses the design, fabrication, and testing of a prototype diffractive scan lens for a 600 dpi laser printer system.

© 1998 Optical Society of America