Patent ID: 7157661
Filing Date: 2007-01-02
Classification: B23K

Abstract:
1. A laser-machining method, comprising: a first process in which a laser beam whose energy intensity distribution is a Gaussian distribution is generated; a second process in which the laser beam is shaped by applying a phase modulation based on a phase distribution expressed by a first order function having a negative gradient, the position in the direction of the beam diameter being the variable, with respect to the wavefront of the laser beam, so that the phase will relatively lead as coming closer to the center thereof and the phase will relatively lag as coming away from the center; a third process in which the laser beam is shaped by applying a phase modulation based on a phase distribution expressed by an n-th order function having a positive gradient (n is a natural number no less than 2), the position in the direction of the beam diameter being the variable, with respect to the wavefront of the laser beam that has been shaped through the second process, so that the phase will relatively lag as coming closer to the center thereof and the phase will relatively lead as coming away from the center; and a fourth process in which the laser beam, whose energy intensity distribution has been made substantially flat through the second and third process, is led to irradiate a machined body, thereby machining the machined body.