Method of checking for the presence of connection balls
AssigneeSiemens Aktiengesellschaft
InventorHans-Horst Grasmüller
Life of this patent
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Abstract
Method of checking for the presence of connection balls of components, in particular of ball grid arrays by projecting light obliquely onto the components to create reflections and shadows at the connection balls and any impurities, detecting the reflections and shadows and evaluating the detected shadows and reflections to determine which are from connection balls and which are from impurities.
Claims1
A method of checking for the presence of connection balls on components, including ball grid arrays by illuminating the connection balls by light which is obliquely incident from one direction, detecting light reflections from the connection balls by an image-evaluating unit connected downstream of an imaging optical arrangement and evaluating a shadow cast laterally with respect to the connection balls and resulting due to the obliquely incident light by the image-evaluating unit the improvement comprising using the size of the shadow to be expected given a specific size of the connection ball, in conjunction with the presence of the associated light reflection from the connection ball as a criterion for automatically checking for the presence of connection balls.
Dependencies are inferred from the claim text.