System for inspecting pattern defects of printed wiring boards

A device for detecting misregistration of printed wiring boards supplied to an inspection system for said printed wiring boards with respect to reference points (X.sub.0, Y.sub.0) of two-dimensional perpendicular coordinates (X--Y) previously defined in said inspection system, said device comprising:

• image input means for sequentially scanning prescribed areas provided with circular marks formed in prescribed positions with respect to wiring patterns of said printed wiring boards and including said reference points (X.sub.0, Y.sub.0) thereby to convert patterns of said prescribed areas into time series signals;
• binarization means for binarizing said time series signals from said image input means along the contents of said prescribed areas;
• counter means for counting numbers of pixel signals concerning said marks outputted from said binarization means with respect to an X-axis direction and a Y-axis direction respectively;
• and
• updown switching control means for switching and controlling respective ones of said counter means from upcount to downcount or from downcount to upcount at points of time corresponding to said reference point (X.sub.0) in said X-axis direction and said reference point (Y.sub.0) in said Y-axis direction,
• amounts of deviation from said reference points (X.sub.0, Y.sub.0) being found on the basis of integrated counter data obtained in respective ones of said counter means.

A device for inspecting pattern defects of printed wiring boards comprising:

• a table for receiving said printed wiring boards having positioning marks being in prescribed positional relation to wiring patterns;
• image pickup means for performing image acquisition of inspected areas of said printed wiring boards positioned on said table;
• binarization means for converting output signals from said image pickup means into binary data;
• storage means for storing pattern data on the basis of said binary data;
• deviation detecting means for reading said positioning marks thereby detecting amounts of deviation from reference coordinates in which said marks are to be positioned;
• misregistration operating means for operating and finding the amount of relative misregistration between a printed wiring board formerly placed on said table and another printed wiring board subsequently placed on said table on the basis of data on said amount of deviation found by said deviation detecting means;
• and
• misregistration correction control means for controlling reading from said storage means storing pattern data of said former printed wiring board on the basis of said data on said amounts of said relative misregistration obtained by said misregistration operating means to be in alignment, when said inspected area of said subsequently placed printed wiring board is subjected to image acquisition by said image pickup means and said binarization means outputs binary data, with said subsequent pattern data concerning said binary data while controlling arrangement of said read pattern data, thereby to compare both pattern data in pixel correspondence by said misregistration correction control means.

A device for inspecting pattern defects of printed wiring boards comprising:

• a table for receiving said printed wiring boards having positioning marks being in prescribed positional relation to wiring patterns;
• image pickup means for performing image acquisition of inspected areas of said printed wiring boards positioned on said table;
• binarization means for converting output signals from said image pickup means into binary data;
• storage means for storing pattern data on the basis of said binary data;
• deviation detecting means for reading said positioning marks thereby detecting amounts of deviation from reference coordinates in which said marks are to be positioned;
• misregistration operating means for operating and finding the amount of relative misregistration between a printed wiring board formerly placed on said table and another printed wiring board subsequently placed on said table on the basis of data on said amount of deviation found by said deviation detecting means;
• misregistration correction control means for controlling reading from said storage means storing pattern data of said former printed wiring board on the basis of said data on said amounts of said relative misregistration obtained by said misregistration operating means to be in alignment, when said inspected area of said subsequently placed printed wiring board is subjected to image acquisition by said image pickup means and binarization means outputs binary data, with said subsequent pattern data concerning said binary data while controlling arrangement of said read pattern data, thereby to control both pattern data in pixel correspondence by said misregistration correction control means;
• and means for data-compressing said binary data outputted from said binarization means and means for restoring said compressed data read from said storage means to said original binary data.