An improved optical system for scanning optical codes is disclosed. A laser beam produced thereby is a diverging, nearly diffraction free beam and may be used to produce an elongated scanning spot. An aperture may be employed such that variation in size of the aperture in one orthogonal dimension varies...http://www.google.com.au/patents/US6540145?utm_source=gb-gplus-sharePatent US6540145 - Aperture controlled laser beam shaping techniques for scanning optical code
