away as seen in fig1 and 16 lens blanks 116 with the desired curvature are then cut out from the remaining parent blank 110 by any suitable cutting tools such as a band saw the cylindrical surfaces 118 120 of each lens blank is then ground to an appropriate radius of curvature r 1 r 2 respectively these cylindrical surfaces are then polished to form the tegil with reference to fig1 21 the pre objective scan design in which the scanning mechanism polygon is placed before the objective scan lens 128 comprises three optical elements and a rotational polygon mirror 126 the polygon is 42 1 mm in diameter and has 18 facets an unfolded schematic of the system in the yz plane is shown in fig1 the light enters the first cylindrical corrector lens 122 and is focused onto a facet 126 of the polygon a second field corrector lens 124 is positioned one focal length away from polygon 126 to recollimate the light the collimated beam then enters the objective scan lens 84 and is focused onto a recording medium at the receptor plane 88 the scan of the polygon 126 covers an 8 5 inch page as discussed any cross scan error due to the polygon wobble or facet tilt will be compensated as the light is recollimated after.