The measurement of the misalignment induced aberration of a miniature lens

The manufacturing errors of an optical system are in different types of tolerance categories. Among these tolerance categories, the optical surface figure error and the surface / element alignment errors are the two most important factors in determining the optical system performance. In the large optics, the optical surface figure error is typically the dominating factor while the alignment are, for most of time, the most critical factor in the miniature optics. However, the optical testing of the miniature optics alignment is difficult and sometimes nearly impossible to be achieved properly. The misaligned lens element induce the unsymmetrical optical aberration spanning throughout the optical field. This type of aberrations usually dominates near the edge of the field if the misalignment is near its tolerance limit. We proposed a novel method utilizing an ultra-high dynamic range wavefront sensor (UHDR-WFS) to measure the off-axis aberrations of a miniature lens near its field edge. The unsymmetrical aberration is measured by spin-scanning the optical field of the tested miniature lens along the azimuthal direction. A F/2.0 optical beam out of a miniature lens is measured directly without using any collimator. The preliminary test result showing that the constant coma aberration are the dominating aberration of a misaligned miniature lens. The measurement result does matches our expectation from the simulation in the ray tracing software.