Patent ID: 7152796

Claim:
A bar code symbol scanning system for producing a 3-D scanning volume substantially free of spatially and temporally coincident scanning planes, said bar code scanning system comprising: a housing; a plurality of light sources disposed within said housing, for producing a plurality of light beams; light beam scanning disc disposed within said housing, rotating about an axis of rotation, and having a plurality of holographic optical elements for scanning said plurality of light beams and producing within a 3-D scanning volume, a plurality of scanning planes for scanning a code symbol; a plurality of photodetectors disposed within said housing, each said photodetector being associated with one said light source and being capable of detecting light reflected off a code symbol scanned by the light beam produced by said associated light source; and wherein substantially none of said scanning planes within said 3-D scanning volume are spatially and temporally coincident with any other scanning plane in order to ensure that there is substantially zero cross-talk at said plurality of photodetectors.