Multimode optical source and image scanning apparatus using the same

摘要

A focused laser beam is provided using a multimode laser of a type that generates a diverging beam with an asymmetric cross section. A collimation lens receives and substantially collimates the diverging asymmetric beam. An anamorphic beam expander enlarges a width of the substantially collimated beam in a first, multimode axis without substantially affecting the width of the beam in a second, single mode axis orthogonal to the first axis. Demagnification optics are arranged to receive and demagnify the enlarged width beam to produce a focused spot. The demagnification optics can include a cylindrical lens ("rod lens") having a longitudinal axis and arranged to receive the enlarged width beam in a direction substantially perpendicular to the axis. The demagnification optics are merged with scanning optics to produce a scanned spot imaging system. The apparatus is particularly useful for exposing images, e.g., in a dye sublimation printer.