| 摘要 |
The invention concerns a method of checking for the presence of component connection balls, in particular of ball grid arrays. With known methods, the light reflex (6) of connection balls (2) which is produced during illumination (5) is evaluated by an image-evaluating unit (15). Metal impurities (3) can likewise produce light reflexes (11) which are then misinterpreted. The novel method is designed to prevent such misinterpretations. According to the invention, the image-evaluating unit additionally detects the lateral shadow (7) cast by the connection balls (2) when illuminated laterally by a light source (5) which differs from the shadow (12) cast by metal impurities (3). By jointly detecting the reflex and shadow, the image-evaluating unit detects both metal impurities (3) and dark impurities (4) of the same size as the shadow of a connection ball. |
