Laser scanning based bar code symbol reading system for producing a 3-D scanning volume substantially free of spatially and temporally coincident laser scanning planes

A laser scanning based bar code symbol reading system for producing a 3-D scanning volume substantially free of spatially and temporally coincident laser scanning planes, said laser scanning based bar code symbol reading system comprising:

• a housing;
• a plurality of laser sources disposed within said housing, for producing a plurality of laser beams;
• a plurality of photodetectors disposed within said housing, wherein each said photodetector is assigned to only one of said plurality of laser sources for detecting laser light produced by said laser source;
• and
• a laser beam scanning mechanism disposed within said housing, for scanning said plurality of laser beams and producing a plurality of laser scanning planes within a 3-D scanning volume, for scanning a code symbol on a object as the object is moved through said 3D scanning volume;
• wherein substantially none of said laser scanning planes within said 3-D scanning volume are spatially and temporally coincident with any other laser scanning plane in order to ensure that laser light produced by each said laser source is only detected by its assigned photodetector to ensure that substantially zero cross-talk is generated at said plurality of photodetectors.