| 摘要 |
A document scanner includes: a document support for supporting a document in position to be scanned; an illumination system located adjacent to the document support for illuminating at least a portion of a supported document; a photosensitive medium for capturing an image of the document and generating image information; and a retroreflective imaging lens having an F-number between F/3 and F/8. The retroreflective lens comprises at least one lens element with optical power and a reflective surface, and is positioned to (i) receive light emanating from the document and propagated it in a first direction, through the retroreflective lens, (ii) reflect the light off said reflective surface in a second direction, and (iii) propagate the light through the retroreflective lens in the second direction, towards the photosensitive medium. The document support, the photosensitive medium, and the retroreflective lens are in a fixed spatial relationship relative to one another. According to one embodiment of the present invention the illumination system provides less than 1 watt of power.
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