Fast, comprehensive and reliable testing of micro-optical elements and systems

In the last years, optics in the millimeter (and below) range found their way into various applications. Due to the large quantities that arise when such components are applied in mass products, a fast, comprehensive and reliable method for testing the sub-components is neccessary before the system is assembled. A Shack-Hartmann sensor based measurement platform has been developed to fulfil the requirements for speed and stability. For testing plano concave micro lenses on wafer level, a high reproducabitily of the measured values could be achieved at a low cycle time (less than 3s). The null testing of a single micro lens allows for contactless characterization of surfaces with high aperture (up to 0.7). The center thickness was measured with a reproducability much better than 1µm, while the mean radius of curvature of lenses with ROC~570µm was reproduced better than 0.5µm. The absolute accuracy of the ROC measurement has been verified by calibration objects. The individual measurement also registers the deviation from the best fitted sphere and thus the complete surface shape. Besides the evaluation for a single element the measured data can also be analyzed statistically.