| 摘要 |
An improved method and apparatus for reading optical information over a substantial range of distances provides an optical string, disposed in a housing, for refracting images of optical information of varying wavelengths to different focal points along a longitudinal axis at a predetermined reading position. Adjacent the housing, and directed along the longitudinal axis of a housing opening and the optical string, is an illumination source for illuminating optical information with light. Also included is a reading sensor having a light receiving plane disposed at a predetermined reading position behind the optical string for converting an image of optical information into an electrical signal. A control system is also provided for determining and decoding the reflected light image formed by that wavelength of light received from the illumination source which produces the best focus on the light receiving plane of the reading sensor. Finally, an apparatus is also provided for producing a digital information set corresponding to the image of optical information focused by the optical string onto the receiving plane of the reading sensor.
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