| Summary: | 碩士 === 華梵大學 === 機電工程研究所 === 93 === The diamond scribing and laser breaking technique for LCD glasses were investigated in this paper. A point diamond or diamond wheel is used to generate a groove-crack along the cutting path in a glass surface. The glass substrate is then separated by applying a defocused CO2 laser beam throughout the scribed line for driving the groove-crack through the glass thickness. The diamond scribing will generate a groove and median crack. The relationships between the scribing force, groove depth, crack depth, and the breaking speed that can be attained were obtained. The scribing can enhance the cutting speed that can be attained during the cutting process, and improve the straightness of the breaking surface. The material separation is similar to crack propagation. For the large laser spot, the extension of the crack tip lags behind the laser spot. On the other hand, the extension of the crack tip overtakes the laser spot for the small laser spot. The crack extends top-down from the groove bottom and will extend throughout the substrate. Because the initiated groove-crack will propagate exactly along the scribed line, the straightness of the breaking trajectory is very good. The SEM photographs of the breaking surface and the acoustic emission data were obtained to analyze the fracture mechanism during the laser cutting process. Finally, the finite element software ANSYS was employed to calculate the temperature and stress distributions.
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