基于偏心抑制的激光差动共焦焦距高精度测量方法

Considering that the eccentricity error in the process of measuring the focal length of spherical lens results in the uncoincident measured optical axis relative to the actual axis of lens, a high-precision measurement method of laser differential confocal length based on eccentric suppression is proposed, where the size and direction of the lens′ center deviation are measured by rotating the table to realize the error acquisition of measured lens. By analyzing the error value and direction driving attitude adjustment motor, the influence of eccentricity error on the accuracy of focal length measurement is eliminated during the measurement process. By constructing the system and optimizing the system parameters, the high-precision measurement of laser differential confocal length is realized. Finally, the high-precision measurement of focal length based on eccentricity suppression is realized, which solves the problem that the measurement results are affected by the uncoincident measured optical axis relative to the actual axis of the lens during focal length measurement. Based on this system, the focal length measurement experiment results show that the relative repeatability measurement accuracy (RMS) can reach 0. 000 503% when the focal length is measured with a 100 mm lens. This method significantly improves the accuracy of focal length measurement and repeated measurement accuracy, which provides an effective way for precision measurement of focal length. At the same time, this method can be utilized for the processing and assembly of the lens group to improve the imaging quality and measurement accuracy of the lens group.