Image Number 11 for United States Patent #6476962.
A multi-beam zoom lens for producing variable spot sizes on a photosensitive medium from a plurality of individually modulated light sources wherein each light source emits a light beam parallel to each of the other light sources and parallel to an optical axis and wherein a numerical aperture of each of said light beams is greater than 0.125, comprising an afocal zoom lens (10). The afocal zoom lens comprises a first moving group of lenses (13), a second group of moving lenses (14), and a third group of moving lenses (15). A constant barrel length of the afocal zoom lens is less than 160 mm and the zoom lens has a constant distance from the light sources to the photosensitive medium of less than 180 mm. The zoom lens has an afocal magnification of at least 45% across a zoom range.