Patent ID: 7304265

Claim:
A method for cutting brittle material by irradiating laser light from a laser light source onto a brittle material to generate thermal distortions over a wide range of the brittle material, providing cracks in the interior of the brittle material and moving that irradiating position along a predetermined line of the brittle material to cut the brittle material, the brittle material having a front face surface and an opposite rear face surface, the method comprising: providing a plurality of optical fibers which guide laser lights from a plurality of laser light sources to the brittle material; driving the plurality of laser light sources, with the plurality of optical fibers in a bundled condition such that irradiating spots of the lights irradiating the brittle material are arranged in a matrix arrangement, for irradiating a composite laser light at a selected composite laser light intensity which achieves a predetermined shape onto the front face surface of the brittle material being irradiated; measuring a light intensity distribution of the composite laser light on the irradiated front face surface of the brittle material; measuring a light intensity of the composite laser light transmitted through the brittle material to the rear face surface of the brittle material; and in response to measuring the light intensity distribution, adjusting the light intensity distribution of this composite laser light by controlling respectively the light intensity of the plurality of the laser light sources and, if the light intensity on the rear face surface of the brittle material is not appropriate, controlling the selected composite laser light intensity, wherein individual ones of the irradiated spots of light arranged in the matrix arrangement occupy separate individual locations on the front face surface of the brittle material and individual ones of the guided laser lights are emitted directly from respective ones of the plurality of optical fibers onto the front face surface of the brittle material without any lens or lenses interposed between the optical fibers and the brittle material.