Optical system for changing laser beam spot size during scanning of scanning line

摘要

A recording optical system comprises: a laser light source; means for modulating an intensity of a laser beam emitted from the light source; means for shaping a cross sectional shape of the laser beam; means for controlling the modulating means and the shaping means; and deflecting and focusing means for focusing and scanning the shaped laser beam onto the scanning surface. The laser beam size in the direction (sub scanning direction) perpendicular to the scanning direction is varied on the scanning surface by the shaping means, during the recording operation.