| 摘要 |
A scan pattern for a bar code scanner is produced by the combination of a coherent light source, a rotating disc with holographic facets and an array of fixed, beam folding mirrors. Light reflected from a bar code label follows a retroreflective path to a photodetector within the scanner. To reduce variations in the amount of light collected through different facets, the areas of the facets are varied as a function of beam elevation and beam path length.
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