| 摘要 |
A holographic scanning system for scanning a bar coded label is disclosed in which the light beams of a laser are directed at a set of holograms located on a rotating disk in which each hologram will generate an individual scan beam having a slightly different focal length and direction angle from that of the other holograms. Each of the scanning beams is directed at a plurality of mirrors which reflect the beams in the form of a scanning pattern on a scanning area through which a coded label on an article will pass. Each of the scanning beams is projected in an overlapping relationship on the scanning area, thereby providing an enhanced depth of focus enabling a more effective reading operation. The light reflected from the bar coded label is collected by the holograms for collimating the reflected light beams. The collimated light beams are directed at a lens member which focuses the received light beams on a photodetector for use in reading the bar coded label. |
