Rapid pattern inspection of shadow masks by machine vision integrated with Fourier optics

Sang-Yoon LeeDong-Seon YoonKorea Advanced Institute of Science andTechnologyDepartment of Mechanical EngineeringYusong-gu, Taejon, 305-701KoreaAbstract. We present a machine vision inspection method that is spe-cially devised to detect defects on shadow masks. This method incorpo-rates Fourier optics to capture only irregular defects in real time by block-ing out the periodically repetitive pattern of normal mask holes using apinhole type spatial filter under coherent illumination. In addition, a fastdefect-detection image processing algorithm efficiently suppresses un-desirable background noisy images. Experimental results prove that thismethod provides a detection capability of 500 mm