抄録
This paper describes a new visual inspection method for grid structure films used for elements of display unit. The main target of inspection is SHADING DEFECT, which is caused by unevenness of grid line width. Degree of shading defects defies measurement in numerical terms, so in many cases SENSORY INSPECTION by human operators are adopted in manufacturing sites. The new method is based on a diffraction effect of laser beam. The diffraction pattern varies due to grid's characteristic. Variations of the diffraction pattern with the defects have been proven by simulations and experiments. The defect detection method by image processing with CCD area sensor is proposed. The method is applied on several defective sample films. The results proved that the defects could be detected by the intensity profiles of the images. The effectiveness of this method at the manufacturing sites is described. Quantitative evaluation of shading defects is proposed.
