Autofocus module having a diffractively achromatized toroidal lens
First Claim
1. An autofocus module for determining the distance of an object from a detector plane, comprising:
- means for generating a beam of light that is divergent in the horizontal direction and collimated in the vertical direction said beam of light reflecting from an object in its path;
at least one pair of receiver lenses which have focal lengths that are longer and shorter than the distance to the detector plane positioned to receive the beam of light reflected from the object;
at least one pair of photodetectors each positioned at the detector plane and associated with one of said pair of receiver lenses for providing output signals indicative of the reflected intensity received from the object; and
means for determining the difference in output signals from said at least one pair of photodetectors whereby said difference is a function of the distance of the object from the detector plane.
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Accused Products
Abstract
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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Citations
18 Claims
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1. An autofocus module for determining the distance of an object from a detector plane, comprising:
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means for generating a beam of light that is divergent in the horizontal direction and collimated in the vertical direction said beam of light reflecting from an object in its path; at least one pair of receiver lenses which have focal lengths that are longer and shorter than the distance to the detector plane positioned to receive the beam of light reflected from the object; at least one pair of photodetectors each positioned at the detector plane and associated with one of said pair of receiver lenses for providing output signals indicative of the reflected intensity received from the object; and means for determining the difference in output signals from said at least one pair of photodetectors whereby said difference is a function of the distance of the object from the detector plane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An autofocus module, comprising:
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means for generating a beam of light that is divergent in the horizontal direction and collimated in the vertical direction; at least one pair of receiver lenses each having the same focal lengths; at least one pair of photodetectors each positioned nearer and further than the focal lengths of a respective receiver lens for providing signals indicative of the reflected intensity of the generated beam from an object; and means for determining the difference in output signals from said at least one pair of photodetectors whereby said difference is a function of the distance of the object from the autofocus module. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification