In the laser scribing of glass a thermal stress is introduced into a glass plate by means of CO2 laser irradiation. The glass plate is rapidly cooled down by water jet immediately after the irradiation. For the purpose of theoretical clarification of the factors ruling the scribable condition & crack depth, scribable conditions were acquired in laser irradiation experiments using a soda-lime glass plate having a thickness of 0.7mm. Furthermore, the crack depth & crack profile were observed for various values of the distance between the heating & cooling area. On the basis of the scribable conditions obtained from the experiments, a three-dimensional thermal stress analysis was conducted by a finite element method. The scribable condition can be estimated from the maximum surface tensile stress in the cooling area & the maximum surface temperature. The crack depth in laser scribing depends on the surface tensile stress in the cooling area and the compressive stress field immediately under that area.
