| 摘要 |
A scanner for reading bar codes on labels uses a non-coherent light source 11 below a top window 7 to illuminate a code label passing over the window. A lens system focuses an image of the code label onto a photosensitive diode array 25 and onto a photodetector 37. Signal information from the diode array 25 is provided to a code reading circuit 41 when bars on the code label are aligned substantially perpendicular to the array 25. When the bars are not aligned substantially perpendicular to the array 25, the photodetector 37 provides the code reading circuit 41 with pulse signals, transmitted when successive bars on the label pass into focus over the photodetector 37. The system avoids the use of coherent (laser) light and is suitable for reading UPC labels on packages being passed over the window 7.
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