Optical scanning system for bar code - has two laser diodes generating two optical beams, each beam directed to opposite side of rotating polygon mirror and mirror array, scan patterns generated for each are combined to scan object

摘要

The system scanner (10) simultaneously generates two optical beams through lower and upper windows (20,25). They are simultaneously reflected off opposite sides of a polygon mirror (30). The windows are oriented at 150 degrees angle (theta ) to each other. The mirror arrays (60,80) are positioned on opposite sides of the polygon mirror. Hence the scan planes from the mirror array intersect in the scan volume where the objects to be scanned are passed. The lower light source (76) beam is focused and reflected to the polygon mirror (30) which rotates and directs it across the lower mirror array (80). It is reflected through the lower window. Light reflected off the target returns via the same path, is collected (72) and focused onto the detector (79). The upper beam is directed from a light source (56) to the mirror (54). It is focused, reflected and directed across the upper mirror array (60) and reflected through the upper window (25). Light reflected off the target returns by the same path, is collected (52), reflected off the fold mirror (58) and focused onto the detector (59).