Abstract: Provided are a processing method for forming division originating points in a workpiece and a laser processing apparatus performing the method, which are capable of reducing light absorption in a processing trail, increasing light extraction efficiency from sapphire, and performing high speed processing. A pulsed laser beam is irradiated to a workpiece so that irradiation regions for each of unit pulsed beams of the pulsed laser beam of ultra-short pulse are formed discretely in the workpiece, and cleavage or parting of the workpiece is sequentially generated between the irradiation regions by a shock or a stress when each of unit pulsed beam is irradiated at an irradiation point, to thereby form originating points for division in the workpiece.

Abstract: Provided are a processing method for forming division originating points in a workpiece and a laser processing apparatus performing the method, which are capable of reducing light absorption in a processing trail, increasing light extraction efficiency from sapphire, and performing high speed processing. A pulsed laser beam is irradiated to a workpiece so that irradiation regions for each of unit pulsed beams of the pulsed laser beam of ultra-short pulse are formed discretely in the workpiece, and cleavage or parting of the workpiece is sequentially generated between the irradiation regions by a shock or a stress when each of unit pulsed beam is irradiated at an irradiation point, to thereby form originating points for division in the workpiece.

Abstract: A laser processing method for performing laser processing for reducing light absorption on a processing trail is provided. When an irradiated range on a surface of a workpiece is modulated by modulating an irradiating state of a pulse laser beam from a light source, a processed region which has a continuous portion in a first direction and in which a state of a cross section vertical to the first direction changes in the first direction is formed. Concretely, scanning by means of the pulse laser beam is performed under an irradiating condition that beam spots of the laser beam per unit pulse are discrete along the first direction, or scanning by means of the pulse laser beam in the first direction is performed while the irradiation energy of the pulse laser beam is being modulate, or scanning by means of the pulse laser beam in a second direction and a third direction that have predetermined angles with respect to the first direction are alternatively repeated.

Abstract: A core for magnetic head, which has a surface roughness of not higher than 2 .mu.m in the side wall of a groove for defining the track width of the core, can be obtained by subjecting at least a portion, which defines the track width, of a gapped bar made of ferrite and having a coil turn hole and a magnetic gap, to a laser-induced etching under a condition that a laser light having a power of 50-1,100 mW and a focused beam diameter of not larger than 20 .mu.m is irradiated to at least the track width-defining portion at a scanning speed of 2-110 .mu.m/sec in a halogen gas- or halide gas-containing atmosphere kept to a gas pressure of 10-200 Torr.