PURPOSE: To provide for a through-hole inspection device where a defect of the through-hole including a plating thickness failure of a metal layer which is formed by plating can be detected positively without being affected by a material of an insulation film regarding the through-hole inspection device, especially a device for detecting a defect of a metal layer which is formed by plating within a through-hole which is formed at an insulation film of a printed-wiring board.
CONSTITUTION: A title item consists of a ring-shaped light-emitting means 1 for emitting a ring-shaped light to a side wall of a through-hole 53 which is formed at an insulation film 52, an image pick-up means 2 for picking up an image of a ring-shaped lighting rays 57 which are formed at a side wall of the through-hole 53 by ring-shaped light which is emitted by this ring-shaped light-emitting means 1, and a through-hole judging means 33 for calculating an amount of displacement from a roundness of the ring-shaped lighting rays 57 which are picked up by this image pick-up means 2 and then judging that a defect exists at the through-hole 53 when the amount of displacement exceeds a prescribed value.
NISHIYAMA YOJI
ANDO MORITOSHI
