「Well prepare the tools prior to finish your job」 The critical component to the inspection of LCD Display Panel is the optical light source. An optimum wavelength of the light source, from the CCD or human eye point of view, can improve the astheropia and even result in the upgrade of inspection power. The incandescent light is fit for human eye, however, the yellowish green light is better for the identification of blemish and flaw. This study is based on the spectrum that measured via Monochromator and Optical Microscopic.We try to pursue the most optimum light source through the application of statistical analysis of regression equations.