Study on the glass defects measurements using the critical angle method and a CCD camera

• Main Authors: Chien-Chen Lee, 李建成
• Other Authors: 邱銘宏
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/2bn5mv

碩士 === 國立虎尾科技大學 === 光電與材料科技研究所在職專班 === 99 === The purpose of this thesis is to combine the critical angle method with CCD image capture technology for measuring the scratches on the LCD glass substrate. The panels of mobile phones, LCD TVs, digital cameras and tablet PCs etc with glass substrates are high-technique produces in modern life. The serious defects in or on the glass, like as, scratches, bubbles, or smudges, etc, will affect the image quality of display. In this method, when the expanded laser beam passes through the transparent component, the surface information is added in it. We use a rotating stage to control the incident angle of a parallelogram prism. Two incident angles, the critical angle and the angle of total internal reflection (TIR), are set to measure the image pattern of the glass using a CCD camera, respectively. Use the data of two patterns to calculate the reflectance profile and use the principle of the first-order geometrical optics to calculate the surface profile using the MATLAB program. From the surface profile results, how the quality of the glass is detected. The method has some merits, such as, simple structure, easy operation, high sensitivity, and it can measure a wide range of transparent surface defects.