Protrusive Detection for Thin Film Transistor-Liquid Crystal Display Using Side-view Illumination

Protrusion adhered onto the glass substrate of the thin-film transistor liquid crystal display (TFT-LCD) is a yield killer to damage the valuable photo-mask frequently. An innovative method using side-view illuminations associated with digital charge couple devices (CCDs) to detect the protrusion for color filter panel of the black matrix (BM) film and photo resistance (PR) red (R), green (G), and blue (B) film balls of TFT-LCD is developed in this study. Between the photo-mask and glass substrate, the gap is 300 mu m; the height of the protrusive of the species at 280 mu m, 277 mu m, 256 mu m and 265 mu m are simulated on the inspection platform. The method indicates the significant detect of the protrusion that reaches to 300um and even lower than 200um. The maximum error of the measurement is within 6% among of species. Furthermore the uncertainty analysis of 3-standard deviation are at 23 mu m, 15 mu m 18 mu m and 20 mu m with respect to BM, R, G and B filmed glass balls. Thus, the method is a cost effective inspection to prevent the damage for valuable photo-mask in TFT-LCD s industry.