A laser recording apparatus has a laser light source, an acousto-optical element for optically modulating the laser beam from the laser light source, a beam expander scanning optical system for optically scanning a diffracted light emerging from the acousto-optical element toward a recording surface,...http://www.google.com/patents/US4712117?utm_source=gb-gplus-sharePatent US4712117 - Adjusting apparatus for laser scanning system with acousto-optical element
