| 摘要 |
PURPOSE:To discriminate easily a defect of a through-hole by dividing an inspecting surface of a printed board into picture elements being smaller than a diameter of the through-hole, and comparing a picture element signal of a master printed board with a picture element signal of the printed board to be inspected. CONSTITUTION:The whole area of an inspecting surfacing of a printed board 3 having through-holes 4, 5 at prescribed positions is divided into picture elements 6-8, etc. divided small in a shape of a checkerboard, and it is constituted so that a transmission quantity of a light of each picture element 6-8 is converted to a digital signal. Subsequently, optical information of each picture element 6-8 of the master printed board 3 on which all the through-holes 4, 5 have been formed completely is converted to a binary signal and stored, and next, optical information of each picture element 6-8 of the printed board 3 to be inspected is converted to a binary signal and stored, and the respective corresponding picture element signals are compared. In this way, a defect of the through-holes 4, 5 of the printed board 3 to be inspected can be discriminated easily with a high accuracy. |
