A structured mechanism development and experimental parameter selection of laser scattering for the surface inspection of flat-panel glasses

The surface inspection of flat-panel glass is important in manufacturing processes. In this study, an experimental analysis based on dark-field laser scattering was performed to inspect micro-defects in flat-panel glass for infrared cut-off filters. The laser scattering parameters were investigated and scattering light paths analysed. On the basis of these results, a structured mechanism was designed and an experimental inspection system developed using the mechanism. By examining the effect of changing parameter values, it was found that two dark-field laser scattering parametersthe incident angle of the laser and the viewing angle of the cameraare critical for the intensity and distribution of the scattering light for accurate and robust surface inspection. Also, the difference of these angles is very important. Based on the design of experiment, previous experimental results are evaluated and predominant parameters are optimally determined. The results of the experimental inspection system demonstrate the effectiveness of the proposed method.