An electro-optical triggerless reader reads indicia having parts of different light reflectivity within a limited working range of distances relative to the reader. A light beam is focused to have its minimum beam cross-section, as considered along a scan direction, or waist situated within a...http://www.google.fr/patents/US5783813?utm_source=gb-gplus-shareBrevet US5783813 - Limited working range scanner having focused light beam waist situated within scanner housing
Limited working range scanner having focused light beam waist situated ...
