Automated shadow mask inspection using DSP

Presents a new shadow mask inspection method which can detect the very small hole defects reliably and rapidly; the shadow mask line image data is periodical. The inspection method mainly depends on the fact that a small defect can be significantly emphasized in terms of the comparison between the image pixels departed by the period. In this paper, this comparison is implemented as the digital filtering algorithms, which can be rapidly processed by a DSP chip. In terms of the high speed line image sensing and fast algorithm by DSP, the whole inspection scheme sufficiently supports the real time shadow mask handing. From the experimental results, this scheme shows a reliable inspection capability for all types of individual hole defects