A portable laser diode scanning head, aimable at each symbol to be read, emits and receives non-readily-visible laser light, and is equipped with a trigger-actuated aiming light arrangement for visually locating and tracking each symbol. A compact laser diode optical train and an optical folded path...http://www.google.es/patents/US4816660?utm_source=gb-gplus-sharePatente US4816660 - Portable laser diode scanning head
