Design of projection optical system for 3D defect detection on PCB

Abstract According to the practical experience of PCB defect detection in semiconductor industry, a projection optical system suitable for structured light detection device is designed by using a DMD chip. In order to realize the lateral projection of structured light stripe and improve the quality of system projection, the design of tilt back group of projection lens is adopted and the projection size is 57×32mm.The simulation results show that the illumination uniformity of the projection system on the measured surface is more than 85%, the fringe contrast is larger than 0.5, and the maximum height of the measuring device is 5mm, which provides a guarantee for practical application of structured light fringe for 3D defect detection on PCB.