Method and apparatus for examining through holes

摘要

There are provided a method and apparatus for examining through holes, in which determinations as to whether the examined through hole are good or bad can be accurately made at low costs. A light source and a sensor camera having a plurality of imaging elements are disposed with a table on which a work piece having through holes is mounted being interposed between the light source and the sensor camera. Light passing through the through holes is imaged by the sensor camera, wherein the sensor camera is set such that a focal point of the sensor camera is shifted from the surface of the work piece to thereby apparently expand an area of the image of the passing light.