An Off-Axis Measuring Method of Structural Parameters for Lenslet Array

Aiming at the problem that the vertex detection method is difficult to deal with the high-efficiency detection of the large-scale spherical lenslet array, a contact off-axis measuring method is proposed and the measurement accuracy and detection efficiency are verified by experiments. Firstly, by analyzing the 3D model of the relationship between a spherical lens and probe of profilometer, the mathematical model of probe trajectory arc is established based on the off-axis trajectory characteristics of the spherical lenslet array. Then, the error mechanism under the off-axis condition is analyzed, and a mathematical algorithm is proposed to restore the structural parameters at the main optical axis of the lens by using the process design value of the unit lens aperture. Finally, a comparative experiment is carried out between the off-axis detection method and vertex detection method. The experimental results demonstrate that: Compared with the coaxial detection method, the relative errors of the measured lens curvature radius R₀ and the lens vector height f₀ under the off-axis detection method are 1.71% and 1.95%, respectively. Under the sampling measurement scale, the detection efficiency of the off-axis detection method is 41 times higher than that of vertex detection method.