| 摘要 |
PURPOSE:To separate bending and missing of individual leads by scanning the sample lead terminals in the pitch direction and comparing a change of transmitted light beam with the reference shape data. CONSTITUTION:An image mark 1a which is the inspection criterion is stacked and the one is shifted to the pitch direction. Thereby, a total amount of light beam transmitted of a light source 3 shows the characteristic indicated by polygonal distribution where it becomes maximum temporarily and becomes minimum at the + or -0.5 pitch. In case total of (n) lead terminals 2 are used, there is no superimposition for the pitches more than (n) pitches and the amount of light becomes maximum. The maximum amount of light beam LSmax and the minimum amount of light beam LSmin resulting from the shift are respectively converted to digital signals 8 and stored in an MPU10. When the leads of sample 2 are arranged normally, a polygonal line similar to that obtained for the mark can also be obtained but leads are bending, LSmax reduces but LSmin increases. But if leads are partly missing, LSmas is not required and a value of LSmin for the pitch of + or -0.5 becomes equal to that obtained when the lead is shifted to the outside pitch by pitch and LSmin value increases. The multi-lead can be inspected effectively by comparing these with a stored value of the MPU10. |
