Visual inspection method for part mounted on printed circuit board

摘要

Three different color light beams which are converged to a single light spot on the surface of a circuit board at predetermined incident angles, are irradiated onto the top surface of an electronic part mounted on the circuit board, then distances between the positions of the top surface of the electronic part to which the light beams are irradiated respectively, from the single light spot on the surface of the circuit board are measured, and the height and an inclined angle of the top surface of the electronic part are computed in accordance with the relationship between the measured distances and the incident angles.