| 摘要 |
<p>@ Apparatus for testing a printed wiring board comprising means for optically scanning a board to be tested in two orthogonal, X-Y axes such that for each scan in the Y direction it scans a narrow strip of the board of predetermined width, w in the X direction. The optical scanning means is arranged to provide n.m discrete signals for each scan in the Y direction, wherein n is a predetermined number of signals representative of characteristics of the board across the width w of the strip (typically 1000) and m is a number dependent upon the dimension of the board to be scanned in the Y direction. Processing means is provided for processing the signals in groups of n' x m' where n' is less than or equal to n and m' is less than or equal to m (typically n' and m' are 40) to provide signals representative of the characteristics of the board along said strip and for storing said signals. Control means is arranged to cause the scanning means repeatedly to scan the board in the Y direction and to step it a predetermined amount in the X direction at the end of each scan until a required area of the board has been scanned and the processing means has processed a plurality of said groups of signals. The processing means is further arranged to identify common areas of each conductive track such that at the completion of a test, the storage means contains information representative of the X-Y coordinates of a plurality of datum areas and of the said datum areas which are interconnected. The datum areas may be holes, edge connectors, pads and the like. The processing means also comprises means for comparing the stored signals with a plurality of signals representative of the required interconnections for the board (the required wiring list) thereby to test the quality of the board.</p> |
