Jessica Plaßmann, Tim Eis, Ann-Kathrin Molitor, Valentin-Johannes Bastgen, Georg von Freymann, Michael Schuth

• Reliable inspection of micro-scale components is essential in fields such as electronics and medical device manufacturing. To address this, a method combining digital speckle holography with microscopy has been developed. The resulting “Microferoscope” enables precise detection of structural defects in areas of just a few square millimetres. The method identifies minute deformations induced by controlled external stimuli, such as thermal or mechanical loading. Characteristic deformation patterns reveal structural anomalies. A dedicated module with orthogonal illumination allows for high-resolution measurement of deformations perpendicular to the component surface. Additionally, a three-dimensional module using laser diodes of different wavelengths enables the detection of both in-plane and out-of-plane deformations. Although high sensitivity in out-of-plane detection enhances defect recognition, it also increases susceptibility to environmental disturbances. This study compares both modules on micro-components to evaluate their sensitivity, robustness, and practical applicability.