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Pattern test apparatus

  • US 4,962,541 A
  • Filed: 02/10/1988
  • Issued: 10/09/1990
  • Est. Priority Date: 02/27/1987
  • Status: Expired due to Term
First Claim
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1. An apparatus for testing a testing circuit pattern, comprising:

  • an imaging means for detecting an image signal by scanning a photo-image of the testing circuit pattern;

    a binary coding circuit for converting said image signal to a binary picture element signal;

    a reference binary pattern generating means for generating a reference binary pattern signal in synchronism with said scanning;

    processing means, including a picture image selecting means for selecting a picture element area having a desired dimension from said reference binary pattern signal, an adding means for calculating a sum of all of binary picture element signals derived from said selected picture element area and a comparing means for comparing the sum with a predetermined reference value and giving a reference binary picture element signal obtained by the comparison to a center picture element of said picture element area so that said center picture element is reformed to be substantially analogous to the binary picture element signal of the testing circuit pattern; and

    means for detecting a defect by comparing said binary picture element signal with said reference binary picture element signal for preventing misjudgment of the corner of said testing circuit pattern.

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