Design of lens centering error measuring optical system and stray light analysis

To improve current equipments in the market, a lens-eccentricity-measuring optical system that combines the focusing method and lens-switching method is designed in this paper. This optical system can be used to measure lens with curvature radius from -∞ to +∞, as well as maintain the test accuracy. Lighttools software is used to trace the light ray and analyze stray light distribution of this optical system. Results show that the intensity of the stray light after multiple reflection inside the collimated lens is low and negligible. The stray light intensity becomes stronger when the image distances of sphere centers are nearby in the testing lens. So in the later image processing, the contrast of target images must be strengthened. Measurement experiments are done by using the equipment with this optical system. All the experimental results further verify the correctness of stray light analyzing.