![]() The analysis of the experimental results proves the feasibility of using this method in industrial applications. Preliminary experiments with a 50x objective lens show that the measured values are consistent with the theoretical values, have good linearity and possess a focusing accuracy of 0.2μm within ☓0μm of the focal plane. To control a PZT to achieve real-time auto-focusing, a Gaussian curve fitting method is used to process the spot information with the presented mathematical model giving the relationship between the detection value and the defocus value FES. ![]() The light reflected from the surface of the object reaches a CCD camera and forms a spot via a set of optical devices. The approach combines infrared light at a wavelength of 808nm with visible light. Here, a distance-measuring approach based on the laser triangulation principle is proposed with a corresponding mathematical model to overcome these problems and to satisfy the requirements of an industrial TFT-LCD (thin film transistor liquid crystal display) Inspection Microscope System in active auto-focus applications. Limitations of the pinhole method and astigmatic defocus detection have difficulties in determining the direction of defocus and a restricted linear correction range.
0 Comments
Leave a Reply. |