Patent ID: 6249598
Filing Date: 2001-06-19
Classification: G01R

Abstract:
A solder testing apparatus comprising image detecting means for detecting an appearance image of a soldered portion of an electronic component under testing mounted by soldering leads of the electronic component to pads on a printed circuit board; image processing means for performing image processing on said appearance image to identify shape characterizing amounts of said soldered portion; test parameter storing means for storing image processing parameters used in said image processing means and defect determining parameters used for determining whether said soldered portion is good or bad; and defect determining means for determining whether said soldered portion is good or bad from data derived from said image processing means and the defect determining parameters stored in said test parameter storing means;wherein said image processing means calculates shape factors of a lead and a pad for each soldered portion as shape characterizing amounts for the soldered portion, andsaid solder testing apparatus further comprising:tested-object shape accumulating means for storing shape characterizing amounts of soldered portions identified by said image processing means;tested-object standard shape estimating means for identifying design shape factors of leads and pads as standard shape characterizing amounts, and extracting said standard shape characterizing amounts from the accumulated shape characterizing amounts for soldered portions, based on the shape characterizing amounts for soldered portions stored in said tested-object shape accumulating means; andtest parameter updating means for updating the image processing parameters and the defect determining parameters stored in said test parameter storing means based on said standard shape characterizing amounts;wherein said image processing means identifies, for each soldered portion, shape factors of a solder fillet, together with the shape factors of a lead and a pad, as shape characterizing amounts for the soldered portion; andwherein said tested-object standard shape estimating means statistically processes the shape characterizing amounts for the soldered portions stored in said tested-object shape accumulating means for each type of electronic component mounted on the printed circuit board to identify, from said accumulated shape characterizing amounts for the soldered portions, shape characterizing amounts corresponding to shape factors of leads and pads and shape factors of defective solder fillets which exhibit a low detecting frequency or which cannot be normally derived theoretically from a structural viewpoint, as unnecessary shape characterizing amounts, and to identify shape characterizing amounts corresponding to shape factors of leads and pads an shape factors of non-defective solder fillets which exhibit a high detecting frequency as standard shape characterizing amounts, and extracts said standard shape characterizing amounts from said accumulated shape characterizing amount for the soldered portions.