CUTTER AND METHOD FOR CUTTING BRITTLE MATERIAL SUBSTRATE USING SAME

摘要

Provided is a cutter which can reliably form a diagonal crack further in the direction of the thickness of a brittle material substrate. The cutter has a shape wherein the congruent bottom surfaces of the two circular cones or two circular truncated cones sharing a rotating axis (22) are bonded and the circumferential portion of the bottom surfaces is formed as a blade edge ridge line (21). On the blade edge ridge line (21), grooves (23) tilted by a predetermined angle with respect to the rotating axis direction are formed at predetermined intervals in the circumferential direction. Furthermore, angles (blade angle (?1), blade angle (?2)) formed by the side surfaces of the two circular cones or those of the circular truncated cones and the bottom surfaces are different from each other.