| 摘要 |
<p>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.</p> |
