CUTTER AND METHOD FOR CUTTING BRITTLE MATERIAL SUBSTRATE USING SAME

摘要

A cutter with which a diagonal crack can be created without fail deeply within a brittle material substrate is provided. The cutter has such a form that two cones or truncated cones are joined through the same bottom so as to share the same rotational axis, and the circumference of the above described bottom is used as the blade edge ridge line. In addition, grooves that incline at a predetermined angle relative to the direction of the rotational axis are created around this blade edge ridge line at predetermined intervals. Furthermore, the angles between the sides of the above described two cones or truncated cones and the above described bottom are different from each other.