| 摘要 |
This invention discloses a narrow field of view scanner (10) incorporating two multi-faceted polygon scanning wheels (12, 16) having a slightly different number of facets (14, 18). Each scanning wheel (12, 16) turns at an angular rate such that a facet (14) on one wheel (12) rotates through a predetermined field of view at the same rate as a facet (18) on the other wheel (16). Further, each of the scanning wheels (12, 16) scan in opposite scanning directions. This does not necessarily mean, however, that the wheels are actually rotating in opposite directions. Because both of the scanning wheels (12, 16) are scanning in opposite directions, the scanning of one scanning wheel (16) substantially cancels the scanning of the other scanning wheel (12). Because of the difference in the number of facets (14, 18) between the two scanning wheels (12, 16), the scanning is not entirely cancel out. By this configuration, a dual multi-faceted scanning wheel can scan a much narrower field of view which could be scanned by a single scanning wheel having the same number of facets. The scanning wheels (42, 44) can be configured relative to each other in a variety of different manners, including rotating about a common axis, to satisfy specific design and space requirements of a scanning system.
|
