Automatic measurement of center deviation of lens of laser differential confocal

To address the problems of low measurement accuracy and significant human interference in lens position adjustment in existing center deviation measurement methods，this paper proposes an auto' matic measurement method for the center deviation of differential confocal lenses. This method uses differ' ential confocal focusing technology to precisely locate the cat's eye and confocal points of the measured lens，based on the fact that the zero point of the differential confocal axial light intensity response curve cor' responds precisely to the characteristic point of the measured lens. The high-precision air-bearing rotating shaft drives the rotation of the measured mirror，while the displacement sensor records the position infor' mation of the measured mirror. In combination with the five-dimensional posture automatic adjustment mechanism，the high-precision correction of the attitude deviation of the measured mirror was realized，the eccentricity error was eliminated，and the measurement accuracy was improved. Finally，a laser differen' tial confocal lens center deviation measurement system was established，which automatically measured the lens center deviation with high precision. The experimental results show that the measurement accuracy of the lens eccentricity can reach 0. 41%，while the measurement repeatability is greater than 100 nm. Com' pared with the existing manual single measurement method，the proposed method has good repeatability，small random error，and high measurement accuracy. It serves as a new technical approach for the auto' matic measurement of lens eccentricity with high precision. © 2023 Chinese Academy of Sciences. All rights reserved.