CHENG Liang-lun, PAN Jian-hua. Research of high precision fast focus method for optical auto-detector[J]. 2011, 30(2): 41-43+46. DOI: 10.13873/j.1000-97872011.02.039.
a novel fast high precision AF technology is proposed.Laser beam is condensed to the working table and then the image of laser pattern is formed at the CCD based on laser trigonometry.So the change of gray spot can be used to realize focusing.Experimental results show that repetition focusing precision can reach 0.1μm
focusing time is less than 200ms
and can meet practical application requirements for the industrial optical inspection systems.