Laser confocal auto-collimation decentration measurement for spherical lens

A high-precision confocal auto-collimation decentration measurement method (CADM) for spherical lens is proposed. In comparison with the traditional auto-collimation method, this method employs confocal technology to accurately locate the center of the tested lens, which reduces the focusing error. The radius of curvature and center bias measurements are integrated into one measurement system, which eliminates the random errors introduced by multiple installations. This method also enables the measurement of every surface in the lens group. Theoretical analysis and experiments show that the measurement accuracy of this method reaches 0.335 arcsec. CADM effectively improves measurement efficiency and accuracy, providing a reliable and effective method for the decentration measurement of optical systems.