| 摘要 |
An autofocus module generates a beam of light that is divergent in the horizontal direction and collimated in the vertical direction. The beam is formed using a laser diode and a diffractively achromatized toroidal lens. A pair of receiver lenses which have focal lengths that are longer and shorter than the distance to a photodetector plane are positioned to receive the beam reflecting from an object. A pair of photodetectors, positioned at the photodetector plane, each providing an output signal that is indicative of the amount of light received by a associated receiving lens. The difference in the output signals is a function of the distance of the object from the detector plane and may be used to drive a camera lens to a desired focus position or to provide an indication of the object from the module.
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