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Apparatus and method for inspecting soldered portions

  • US 4,772,125 A
  • Filed: 06/19/1986
  • Issued: 09/20/1988
  • Est. Priority Date: 06/19/1985
  • Status: Expired due to Fees
First Claim
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1. An apparatus for inspecting an appearance of a plurality of soldered portions connected between pads formed on a printed circuit board and leads of an electronic body part comprising:

  • irradiating means for irradiating a slit-like X-direciton excitation light onto leads of an electronic body part extending in a Y-direcition and for scanning in the Y-direction for generating fluorescence from a substrate portion of a printed circuit board on a part of the printed circuit board adjacent a plurality of soldered portions connected between pads formed on the printed circuit board and the leads of the electronic body part;

    detecting means for detecting a two-dimensional fluorescent image formed by a light fluorescent image generated from the substance portion of the printed circuit board and a dark fluorescent image generated from said leads, said pads, and said soldered portions, said detecting means including an image detector means for converting said two-dimensional fluorescent image to an image signal;

    binarization circuit means for converting said image signal to a binarized signal corresponding to said light fluorescent image and said dark fluorescent image;

    Ys(x) detecting means for extracting from said binarized signal a function Ys(x) of Y coordinates for x coordinates of the X-direction indicative of the boundary initially detected as said light fluorescent image from an edge line of a body part proximate to a side edge of said pads in the Y-direction, said Ys(x) detecting means including memory means for storing said function Ys(x);

    Q(x) detecting means for extracting a function Q(x) of projection data by adding picture elements corresponding to said dark fluorescent image of said binarized signal detected on an opposite side of said body part for said boundary Ys(x) in the Y-direction for x coordinates of the X-direction, said Q(x) detecting means including memory means for storing said function Q(x);

    Ys1 (x) calculating means for calculating a function Ys1 (x) by removing line coordinates previously determined from said function Ys(x) read out from said memory means of the Ys(x) detecting means without being influenced by a shade effect of said body part or a lead shoulder portion; and

    defect detecting means for detecting at least one defect of a bridge of solder and a lead slide error in accordance with signals B1 (x) and B2 (x) obtained by comparing said function Ys1 (x) obtained by said Ys1 (x) calculating means and said function Q(x) read out from said memory means of the Q(x) detecting means with pad position information B(x). and masking an x-area of said function Ys1 (x) and said function Q(x) by the pad positional information B(x).

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