During quality-assurance procedures in the mass production of
small-sized curved optical lenses, fine defects are usually detected
via manual observation, which is not recommended owing to the
associated drawbacks of high error rate, low efficiency, and
nonamenability to quantitative analysis. To address this concern, this
paper presents a comprehensive defect-detection system based on
transmitted fringe deflectometry, dark-field illumination, and light
transmission. Experimental results obtained in this study reveal that
the proposed method demonstrates efficient and accurate detection of
several microdefects occurring in small-sized optical lenses, thereby
providing valuable insights into the optimization of parameters
concerning the mass production of optical lenses. The proposed system
can be applied to the actual mass production of small-sized curved
optical lenses.