| 摘要 |
PURPOSE:To inspect exactly a surface state of a material by supplying an electric signal outputted from a photoelectric converter corresponding to a pattern of a surface of a material to be inspected to two detection circuits having different threshold voltages to discriminate a pulse signal outputted from each detection circuit by a discriminating circuit. CONSTITUTION:If a defect 6 exists at wiring part of a printed board to be inspected and an unnecessary wiring material 7 exists at the part where the wiring should not be formed, the output signal of a photoelectric converting element 5 is shown as a figure (b). The output waveform of a detecting circuit A1 is shown as a figure (c) where pulse is generated at the part in which there are no defect 6 and no wiring due to low circuit Vth. Inversely the output waveform of the detecting circuit A2 is shown as a figure (e) where pulse is generated at the part in which there are no wiring and no wiring material 7 due to high Vth of the circuit. The output signal of the detecting circuit and the signal stored in the discriminating circuit are compared in each discriminating circuit B1, B2, and the output is sent to the display part. The output of a discriminating circuit C1 appears as the pulse indicating the existence of the defect 6 caused in the wiring 3 as shown in a figure (g). |
