| 摘要 |
PURPOSE:To reduce the whole size of an inspection device by providing an illumination means for illumination in a slanting direction from one end part, a detecting means for scattered light from the other end part, and a means which detects a defect in a through hole according to the intensity of the scattered light in the through hole. CONSTITUTION:The illumination means 10 consists of a semiconductor laser 101, a collimator lens 102, and a focus lens 103 and projects a laser spot 7 slantingly at an angle theta to the axial direction of the internal wall plating layer 2a of the through hole 2 of a printed board 1. The scattered light detecting means 11 consists of an objective 111 and a photodiode 112, and the intensity of the scattered light 8 which is incident on one end part of the internal wall plating layer 2a of the through hole 2 and reflected by the plating layer 2a is detected by the photodiode 112 which slants by an angle phi. If the plating layer 2a has a defect 2b, the intensity of the scattered light 8 decreases, so the intensity of this scattered light 8 is detected to decides whether or not the through hole 2 has a defect. |
