Electro-optical inspection

  • US 4,576,482 A
  • Filed: 06/02/1981
  • Issued: 03/18/1986
  • Est. Priority Date: 09/07/1979
  • Status: Expired due to Term
First Claim
Patent Images

1. Apparatus for determining a dimension of an object to an accuracy of at least ±

  • 0.0004 inches comprising;

    an electro-optical sensor unit for sensing the positon of a portion of an object, said sensor unit comprising;

    light source means for illuminating an edge of said portion of an object;

    lens means for forming an image of the illuminated edge of an object;

    a photosensitive array comprising a plurality of light sensitive elements capable of producing a signal in response to light incident thereon, said array being positioned to receive the image of an illuminated edge of an object;

    electronic means for magnifying the resolution provided by said photosensitive array to a fraction of an individual light sensitive element, said electronic means including means for producing a fractional distance signal having a value indicative of the fractional distance between adjacent light sensitive elements; and

    means for analyzing the signals from said light sensitive elements and said fractional distance signal to determine a dimension of said portion of said object to an accuracy of at least 0.0004 inches.

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